liu.seSearch for publications in DiVA
Change search
Refine search result
1234 1 - 50 of 166
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Adolfsson, Per
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Regulatory importance of cyclic nucleotides in smooth muscle growth of the urogenital tract2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Smooth muscle hyperplasia/hypertrophy is, if not responsible for, so at least involved in those diseases, which impair life quality for most people in today's society.

    This thesis, presents a pharmacological investigation, related to the regulatory role of cyclic nucleotides, of smooth muscle hyperplasia/hypeitrophy in human uterine leiomyoma and benign prostate hyperplasia (BPH).

    Four main aspects, with cAMP as a connecting thought, have been analyzed, namely expression and characterization of the adrenergic receptors (AR), determination of adenylyl cyclase (AC)- and phosphodiesterase (PDE)-activity, and finally the connection between mentioned issues and proliferation of cultured smooth muscle cells (smc).

    In the frrst paper, characterization of the a 2-adrenergic receptor (az-AR) subtypes in human myometrium at term pregnancy was examined by combining radioligand binding-studies with reverse transcriptase-polymerase chain reaction (RT-PCR). Results demonstrated a significant eo-expression of α2A and α2B, and a weak indication of the α2C-AR, which however was identified at the mRNA level by the RT-PCR analysis.

    In the next investigatio~ smooth muscle tissue of human uterine leiomyoma (benign smooth muscle tumor) was compared with surrounding myometrial tissue (control). The expression of AR, AC- and PDE-activity was analyzed, as well as the effect of cAMP with respect to growth regulation of cultured leiomyoma smc. Primarily, a significantly reduced ß2-AR expression and AC-activity was detected in leiomyoma compared to control tissue, whereas the PDE-activity was approximately 100% higher. In addition, the α2-AR population in leiomyoma was slightly increased. When cultured leiomyoma smc was treated with cAMP increasing agents as forskolin, an AC stimulating agent, or papaverin, a general PDE inhibitor, a considerable inhibition of DNA replication and protein synthesis was obtained.

    In the thh·d paper, a proliferation study was made on cultured benign prostate hyperplasia smc, were the mitogen effect of lysophosphatidic acid (LPA) and cAMP/cGMP increasing agents was investigated. LPA generated a dose-dependent mitogen response, which was efficiently inhibited, both by forskolin, and by papaverin. In addition, sildenafil (Viagra®), which serve as a potent and selective PDE5 inhibitor, also decreased the LPA mediated growth promotion in a dose dependent manner.

    The last study, demonstrate primarily the expression pattem of LPA receptors (Edg) in BPH smc. Further, the intracellular cAMP changes in LPA stimulated BPH smc and the proliferative effect of the LPA analogue sphingosine 1-phosphate (SIP) was considered. First, all Edg was identified with exception of Edg6. Moreover, the cAMP level was unchanged by LPA per se, whereas co-incubation with forskolin generated a rapid and transient response. Further, SIP generated a divergent response including a LPA equivalent mitogen effect at low concentrations whereas inhibition of DNA replication was obtained at higher concentrations.

    In summary, this project demonstrates that cyclic nucleotides inhibit smooth muscle hyperplasia/hypertrophy in the luogenital tract. These results also suggest that manipulation of cyclic nucleotide level using tissue specific PDE inhibitors might constitute a new therapeutic approach for hyperplasia/hypertrophy related diseases in the urogenital tract.

    List of papers
    1. Characterization of α2-Adrenoceptor Subtypes in Pregnant Human Myometrium
    Open this publication in new window or tab >>Characterization of α2-Adrenoceptor Subtypes in Pregnant Human Myometrium
    1998 (English)In: Gynecologic and Obstetric Investigation, ISSN 0378-7346, E-ISSN 1423-002X, Vol. 45, no 3, p. 145-150Article in journal (Refereed) Published
    Abstract [en]

    The aim of the present investigation was to determine which subtypes of the α2-adrenoceptors are being expressed in the human pregnant myometrium at term pregnancy. In radioligand binding studies, the specific binding of [3H]rauwolscine to human myometrial membranes was specific and of high affinity with Kd of 2.8 ± 0.6 nM and Bmax of 95 ± 5 fmol/mg protein. Results from competition for the binding of [3H]rauwolscine using subtype-selective ligands, oxymetazoline (α2A-subptype), chlorpromazine (α2B-subtype) and prazosin (α2B-α2C-subtype), suggested that the α2A- and α2B-subtypes are being co-expressed. In order to examine if also the α2C-subtype is being expressed we used an optimal concentration of oxymetazoline or chlorpromazine which would block the high-affinity site, equivalent to the α2A- and α2B-subtype respectively. Competition curves of both oxymetazoline and chlorpromazine still showed a significantly better fit using a two-site model, suggesting that the α2C-subtype also is being expressed. The expression of α2C-subtype mRNA was confirmed using reverse transcription-polymerase chain reaction on mRNA isolated from myometrial biopsies.

    In conclusion, our results suggest that all three subtypes of α2-adrenoceptors are being coexpressed in the human myometrium at term pregnancy and that α2-expression is dominated by the α2A-subtype.

    Keywords
    α2-Adrenergic receptors, Subtype, Myometrium, Human, Pregnancy, [3H]rauwolscine, Reverse transcription-polymerase chain reaction
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-80081 (URN)10.1159/000009944 (DOI)
    Available from: 2012-08-20 Created: 2012-08-20 Last updated: 2017-12-07Bibliographically approved
    2. Changes in β2-adrenoceptor expression and in adenylyl cyclase and phosphodiesterase activity in human uterine leiomyomas
    Open this publication in new window or tab >>Changes in β2-adrenoceptor expression and in adenylyl cyclase and phosphodiesterase activity in human uterine leiomyomas
    2000 (English)In: Molecular human reproduction, ISSN 1360-9947, E-ISSN 1460-2407, Vol. 6, no 9, p. 835-842Article in journal (Refereed) Published
    Abstract [en]

    Uterine leiomyoma is a very common benign tumour with unclear pathophysiology in adult women. In the present study we have investigated the expression level of α2- and β2-adrenoceptors, and the adenylyl cyclase and phosphodiesterase activity in leiomyoma tissue compared with adjacent myometrium. Our results show that the α22-adrenoceptor ratio is increased in leiomyoma, due to a significant decrease in β2-adrenoceptor expression. These changes were not due to an increased innervation, as the tumour tissue was completely devoid of nerve fibres. Moreover, the adenylyl cyclase activity of leiomyoma membranes was found to be ~50% lower, whereas the phosphodiesterase activity was significantly increased (by ~100%). We found that stimulating an increase in intracellular cyclic AMP, by adenylyl cyclase activity through β2-adrenoceptors (isoprenaline), by direct enzyme activation (forskolin), or by inhibition of phosphodiesterase activity (papaverine), potently blocked both protein and DNA synthesis in cultured leiomyoma smooth muscle cells. Our results imply the adrenoceptors might be involved in, or a consequence of, leiomyoma growth. The results also suggest a new interesting approach for leiomyoma pharmacotherapy.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-25070 (URN)10.1093/molehr/6.9.835 (DOI)9500 (Local ID)9500 (Archive number)9500 (OAI)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13Bibliographically approved
    3. Lysophosphatidic acid stimulates proliferation of cultured smooth muscle cells from human BPH tissue: Sildenafil and papaverin generate inhibition
    Open this publication in new window or tab >>Lysophosphatidic acid stimulates proliferation of cultured smooth muscle cells from human BPH tissue: Sildenafil and papaverin generate inhibition
    2002 (English)In: The Prostate, ISSN 0270-4137, E-ISSN 1097-0045, Vol. 51, no 1, p. 50-58Article in journal (Refereed) Published
    Abstract [en]

    Background The endogenous substance lysophosphatidic acid (LPA) has been found to generate proliferation of cultured smooth muscle cells (SMC). Therefore, the effect of LPA on human benign prostate hyperplasia (BPH) could be of interest.

    Methods The proliferative effect of LPA on cultured human prostatic SMC from specimens obtained at trans-urethral resection of the prostate (TURP) because of BPH, was analyzed by [3H]-thymidine and [35S]-methionine incorporation. In addition, LPA stimulated BPH SMC were treated with papaverin, forskolin, sildenafil or zaprinast, well known to increase the intracellular level of cAMP or cGMP.

    Results LPA produced a dose-dependent increase in BPH SMC, both regarding DNA- and protein-synthesis with EC50 values of 3 and 10 μM, respectively. Furthermore, both papaverin, a general phosphodiesterase inhibitor regarding cAMP hydrolyzes, and forskolin, an adenylyl cyclase stimulating agent, inhibited the LPA-stimulated DNA replication in a dose dependent manner with IC50  = 2.5, and 0.35 μM, respectively. cGMP increasing agents, such as the NO-donors SIN-1 and SNAP, produced a weak anti-proliferative response. However, both phosphodiesterase 5 inhibitors sildenafil (Viagra®) and zaprinast efficiently blocked DNA replication. In addition, when the protein synthesis was examined, we found that the LPA response was significantly inhibited by forskolin and papaverin.

    Conclusions The major conclusion of this investigation is that the endogenous serum component LPA, is able to promote human BPH SMC growth. In addition, our study indicates that cyclic nucleotides can inhibit this effect. Future clinical studies will be needed to determine if different specific phosphodiesterase inhibitors per se or in combination could represent a new therapeutic possibility for the treatment of BPH.

    Keywords
    BPH, SMC, hyperplastic, PDE, AC, cAMP, cGMP, [H-3]-thymidine, [S-35]-methionine, proliferation
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-47887 (URN)10.1002/pros.10077 (DOI)
    Note
    On the day of the defence day the status of this article was submitted.Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13Bibliographically approved
    4. Characterization of EDG receptor expression and proliferative response in cultured human BPH smooth muscle cells
    Open this publication in new window or tab >>Characterization of EDG receptor expression and proliferative response in cultured human BPH smooth muscle cells
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The endogenous phospholipids, lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are both known to generate a Vvide variety of effects in various cell systems by the endothelial differentiation gene (Edg) receptor family, including 7 different G-protein coupled Edg receptors.

    In this study, expression of LPA- and SlP Edg receptors was examined, and so was the effect with respect to proliferation on cultured BPH smooth muscle cells smc. Mmeover, theresponse on cAMP levels was examined. Finally, a potential link between activation of the MAP kinase cascade and the LPA stimulated proliferation was investigated.

    First, the RT-PCR analysis of the Edg receptors in BPH smc, demonstrated a heterogeneous expression including all receptors except the Edg6 subtype. Further, in contrast to LPA, the mitogen effect of SIP, demonstrated a concentration-dependent biphasic response, including stimulation below 1μM, whereas inhibition was obtained at higher concentrations. Forskolin induced a rapid and transient cAMP response in LPA stimulated cells, with a peak-value after 3 minutes. After 15 minutes the cAMP level had retmned to base-line level. However a gradual increase to 15% of maximum value was obtained after additional 30 minutes, and thereafter a gradual reduction was observed. The mentioned antiproliferative response generated by SIP could not be conelated to an intracellular cAMP increase. Finally, when the LPA treated smc was co-incubated with the MAPK kinase inhibitor PD98059 (10 μM) the mitogen response was eliminated.

    The cAIVIP increase, which was induced by forskolin, corresponds with mentioned antiproliferative effect whereas a similar con-elation was not obtained regarding SIP. The intracellular signal mechanisms triggered by LPA and S1P in BPH smc remain to be further investigated.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-80084 (URN)
    Available from: 2012-08-20 Created: 2012-08-20 Last updated: 2012-08-20Bibliographically approved
  • 2.
    Adolfsson, Per
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Ahlstrand, Christer
    Linköping University, Department of Clinical and Experimental Medicine, Urology. Linköping University, Faculty of Health Sciences.
    Varenhorst, Eberhard
    Linköping University, Department of Clinical and Experimental Medicine, Urology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lysophosphatidic acid stimulates proliferation of cultured smooth muscle cells from human BPH tissue: Sildenafil and papaverin generate inhibition2002In: The Prostate, ISSN 0270-4137, E-ISSN 1097-0045, Vol. 51, no 1, p. 50-58Article in journal (Refereed)
    Abstract [en]

    Background The endogenous substance lysophosphatidic acid (LPA) has been found to generate proliferation of cultured smooth muscle cells (SMC). Therefore, the effect of LPA on human benign prostate hyperplasia (BPH) could be of interest.

    Methods The proliferative effect of LPA on cultured human prostatic SMC from specimens obtained at trans-urethral resection of the prostate (TURP) because of BPH, was analyzed by [3H]-thymidine and [35S]-methionine incorporation. In addition, LPA stimulated BPH SMC were treated with papaverin, forskolin, sildenafil or zaprinast, well known to increase the intracellular level of cAMP or cGMP.

    Results LPA produced a dose-dependent increase in BPH SMC, both regarding DNA- and protein-synthesis with EC50 values of 3 and 10 μM, respectively. Furthermore, both papaverin, a general phosphodiesterase inhibitor regarding cAMP hydrolyzes, and forskolin, an adenylyl cyclase stimulating agent, inhibited the LPA-stimulated DNA replication in a dose dependent manner with IC50  = 2.5, and 0.35 μM, respectively. cGMP increasing agents, such as the NO-donors SIN-1 and SNAP, produced a weak anti-proliferative response. However, both phosphodiesterase 5 inhibitors sildenafil (Viagra®) and zaprinast efficiently blocked DNA replication. In addition, when the protein synthesis was examined, we found that the LPA response was significantly inhibited by forskolin and papaverin.

    Conclusions The major conclusion of this investigation is that the endogenous serum component LPA, is able to promote human BPH SMC growth. In addition, our study indicates that cyclic nucleotides can inhibit this effect. Future clinical studies will be needed to determine if different specific phosphodiesterase inhibitors per se or in combination could represent a new therapeutic possibility for the treatment of BPH.

  • 3.
    Adolfsson, Per
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Haug, Ingrid
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Berg, Göran
    Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Changes in β2-adrenoceptor expression and in adenylyl cyclase and phosphodiesterase activity in human uterine leiomyomas2000In: Molecular human reproduction, ISSN 1360-9947, E-ISSN 1460-2407, Vol. 6, no 9, p. 835-842Article in journal (Refereed)
    Abstract [en]

    Uterine leiomyoma is a very common benign tumour with unclear pathophysiology in adult women. In the present study we have investigated the expression level of α2- and β2-adrenoceptors, and the adenylyl cyclase and phosphodiesterase activity in leiomyoma tissue compared with adjacent myometrium. Our results show that the α22-adrenoceptor ratio is increased in leiomyoma, due to a significant decrease in β2-adrenoceptor expression. These changes were not due to an increased innervation, as the tumour tissue was completely devoid of nerve fibres. Moreover, the adenylyl cyclase activity of leiomyoma membranes was found to be ~50% lower, whereas the phosphodiesterase activity was significantly increased (by ~100%). We found that stimulating an increase in intracellular cyclic AMP, by adenylyl cyclase activity through β2-adrenoceptors (isoprenaline), by direct enzyme activation (forskolin), or by inhibition of phosphodiesterase activity (papaverine), potently blocked both protein and DNA synthesis in cultured leiomyoma smooth muscle cells. Our results imply the adrenoceptors might be involved in, or a consequence of, leiomyoma growth. The results also suggest a new interesting approach for leiomyoma pharmacotherapy.

  • 4.
    Adolfsson, Per I.
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Ahlstrand, Christer
    Linköping University, Department of Biomedicine and Surgery, Urology. Linköping University, Faculty of Health Sciences.
    Varenhorst, Eberhard
    Linköping University, Department of Biomedicine and Surgery, Urology. Linköping University, Faculty of Health Sciences.
    Hultgren, Sitti
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel P. S.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Characterization of EDG receptor expression and proliferative response in cultured human BPH smooth muscle cellsManuscript (preprint) (Other academic)
    Abstract [en]

    The endogenous phospholipids, lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are both known to generate a Vvide variety of effects in various cell systems by the endothelial differentiation gene (Edg) receptor family, including 7 different G-protein coupled Edg receptors.

    In this study, expression of LPA- and SlP Edg receptors was examined, and so was the effect with respect to proliferation on cultured BPH smooth muscle cells smc. Mmeover, theresponse on cAMP levels was examined. Finally, a potential link between activation of the MAP kinase cascade and the LPA stimulated proliferation was investigated.

    First, the RT-PCR analysis of the Edg receptors in BPH smc, demonstrated a heterogeneous expression including all receptors except the Edg6 subtype. Further, in contrast to LPA, the mitogen effect of SIP, demonstrated a concentration-dependent biphasic response, including stimulation below 1μM, whereas inhibition was obtained at higher concentrations. Forskolin induced a rapid and transient cAMP response in LPA stimulated cells, with a peak-value after 3 minutes. After 15 minutes the cAMP level had retmned to base-line level. However a gradual increase to 15% of maximum value was obtained after additional 30 minutes, and thereafter a gradual reduction was observed. The mentioned antiproliferative response generated by SIP could not be conelated to an intracellular cAMP increase. Finally, when the LPA treated smc was co-incubated with the MAPK kinase inhibitor PD98059 (10 μM) the mitogen response was eliminated.

    The cAIVIP increase, which was induced by forskolin, corresponds with mentioned antiproliferative effect whereas a similar con-elation was not obtained regarding SIP. The intracellular signal mechanisms triggered by LPA and S1P in BPH smc remain to be further investigated.

  • 5.
    Adolfsson, Per I.
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Dahle, Lars Olav
    Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Berg, Göran
    Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel P. S.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Characterization of α2-Adrenoceptor Subtypes in Pregnant Human Myometrium1998In: Gynecologic and Obstetric Investigation, ISSN 0378-7346, E-ISSN 1423-002X, Vol. 45, no 3, p. 145-150Article in journal (Refereed)
    Abstract [en]

    The aim of the present investigation was to determine which subtypes of the α2-adrenoceptors are being expressed in the human pregnant myometrium at term pregnancy. In radioligand binding studies, the specific binding of [3H]rauwolscine to human myometrial membranes was specific and of high affinity with Kd of 2.8 ± 0.6 nM and Bmax of 95 ± 5 fmol/mg protein. Results from competition for the binding of [3H]rauwolscine using subtype-selective ligands, oxymetazoline (α2A-subptype), chlorpromazine (α2B-subtype) and prazosin (α2B-α2C-subtype), suggested that the α2A- and α2B-subtypes are being co-expressed. In order to examine if also the α2C-subtype is being expressed we used an optimal concentration of oxymetazoline or chlorpromazine which would block the high-affinity site, equivalent to the α2A- and α2B-subtype respectively. Competition curves of both oxymetazoline and chlorpromazine still showed a significantly better fit using a two-site model, suggesting that the α2C-subtype also is being expressed. The expression of α2C-subtype mRNA was confirmed using reverse transcription-polymerase chain reaction on mRNA isolated from myometrial biopsies.

    In conclusion, our results suggest that all three subtypes of α2-adrenoceptors are being coexpressed in the human myometrium at term pregnancy and that α2-expression is dominated by the α2A-subtype.

  • 6.
    Aifa, Sami
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Aydin, J
    Nordvall, G
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Svensson, Samuel
    Hermanson, O
    A basic peptide within the juxtamembrane region is required for EGF receptor dimerization2005In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 302, no 1, p. 108-114Article in journal (Refereed)
    Abstract [en]

    The epidermal growth factor receptor (EGFR) is fundamental for normal cell growth and organ development, but has also been implicated in various pathologies, notably tumors of epithelial origin. We have previously shown that the initial 13 amino acids (P13) within the intracellular juxtamembrane region (R645-R657) are involved in the interaction with calmodulin, thus indicating an important role for this region in EGFR function. Here we show that P13 is required for proper dimerization of the receptor. We expressed either the intracellular domain of EGFR (TKJM) or the intracellular domain lacking P13 (ΔTKJM) in COS-7 cells that express endogenous EGFR. Only TKJM was immunoprecipitated with an antibody directed against the extracellular part of EGFR, and only TKJM was tyrosine phosphorylated by endogenous EGFR. Using SK-N-MC cells, which do not express endogenous EGFR, that were stably transfected with either wild-type EGFR or recombinant full-length EGFR lacking P13 demonstrated that P13 is required for appropriate receptor dimerization. Furthermore, mutant EGFR lacking P13 failed to be autophosphorylated. P13 is rich in basic amino acids and in silico modeling of the EGFR in conjunction with our results suggests a novel role for the juxtamembrane domain (JM) of EGFR in mediating intracellular dimerization and thus receptor kinase activation and function. © 2004 Elsevier Inc. All rights reserved.

  • 7. Aifa, Sami
    et al.
    Johansen, Knut
    Nilsson, Ulrica K
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Svensson, Samuel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Interactions between the juxtamembrane domain of the EGFR and calmodulin measured by surface plasmon resonance2002In: Cellular Signalling, ISSN 0898-6568, E-ISSN 1873-3913, Vol. 14, no 12, p. 1005-1013Article in journal (Refereed)
    Abstract [en]

    One early response to epidermal growth factor receptor (EGFR) activation is an increase in intracellular calcium. We have used surface plasmon resonance (SPR) to study real-time interactions between the intracellular juxtamembrane (JM) region of EGFR and calmodulin. The EGFR-JM (Met644-Phe688) was expressed as a GST fusion protein and immobilised on a sensor chip surface. Calmodulin specifically interacts with EGFR-JM in a calcium-dependent manner with a high on and high off rate. Chemical modification of EGFR-JM by using arginine-selective phenylglyoxal or deletion of the basic segment Arg645-Arg657 inhibits the interaction. Phosphorylation of EGFR-JM by protein kinase C (PKC) or glutamate substitution of Thr654 inhibits the interaction, suggesting that PKC phosphorylation electrostatically interferes with calmodulin binding to basic arginine residues. Calmodulin binding was also inhibited by suramin. Our results suggest that EGFR-JM is essential for epidermal growth factor (EGF)-mediated calcium-calmodulin signalling and for signal integration between other signalling pathways.

  • 8.
    Aifa, Sami
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Miled, N
    Frikha, F
    Aniba, MR
    Svensson, Samuel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Rebai, A
    Electrostatic interactions of peptides flanking the tyrosine kinase domain in the epidermal growth factor receptor provides a model for intracellular dimerization and autophosphorylation2006In: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 62, no 4, p. 1036-1043Article in journal (Refereed)
    Abstract [en]

    The mechanism by which ligand-activated EGFR induces autophosphorylation via dimerization is not fully understood. Structural studies have revealed an extracellular loop mediated receptor dimerization. We have previously presented experimental data showing the involvement of a positive 13 amino acid peptide (R645-R657, P13+) from the intracellular juxtamembrane domain (JM) of EGFR important for intracellular dimerization and autophosphorylation. A model was presented that suggest that P13+ interacts with a negative peptide (D979-E991, P13-) positioned distal to the tyrosine kinase domain in the opposite EGFR monomer. The present work shows additional data strengthening this model. In fact, by analyzing protein sequences of 21 annotated ErbB proteins from 9 vertebrate genomes, we reveal the high conservation of peptides P13+ and P13- with regard to their sequence as well as their position relative to the tyrosine kinase (TK) domain. Moreover in silico structure modeling of these ErbB intracellular domains supports a general electrostatic P13+/P13- interaction, implying that the C-terminal of one receptor monomer is facing the TK domain of the other monomer in the receptor dimer and vice versa. This model provides new insights into the molecular mechanism of ErbB receptor activation and suggests a new strategy to pharmacologically interfering with ErbB receptor activity. © 2005 Wiley-Liss, Inc.

  • 9.
    Anderson, Tony
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Filippini, Daniel
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Suska, Anke
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Johansson, Therese
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Svensson, Samuel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Frog melanophores cultured on fluorescent microbeads: Biomimic-based biosensing2005In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 21, no 1, p. 111-120Article in journal (Refereed)
    Abstract [en]

    Melanophores are pigmented cells in lower vertebrates capable of quick color changes and thereby suitable as whole cell biosensors. In the frog dermis skin layer, the large and dark pigmented melanophore surrounds a core of other pigmented cells. Upon hormonal stimulation the black-brown pigment organelles will redistribute within the melanophore, and thereby cover or uncover the core, making complex color changes possible in the dermis. Previously, melanophores have only been cultured on flat surfaces. Here we mimic the three dimensional biological geometry in the frog dermis by culturing melanophores on fluorescent plastic microbeads. To demonstrate biosensing we use the hormones melatonin and α-melanocyte stimulating hormone (α-MSH) as lightening or darkening stimuli, respectively. Cellular responses were successfully demonstrated on single cell level by fluorescence microscopy, and in cell suspension by a fluorescence microplate reader and a previously demonstrated computer screen photo-assisted technique. The demonstrated principle is the first step towards "single well/multiple read-out" biosensor arrays based on suspensions of different selective-responding melanophores, each cultured on microbeads with distinctive spectral characteristics. By applying small amount of a clinical sample, or a candidate substance in early drug screening, to a single well containing combinations of melanophores on beads, multiple parameter read-outs will be possible. © 2004 Elsevier B.V. All rights reserved.

  • 10.
    Andersson, Rolf G
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Bartonek, M
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lindström, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lindström, I M
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Toll, Johan B
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Studies of the mechanism of desensitization of anti-IgE-mediated histamine release from human basophils1989In: Agents and actions, ISSN 0065-4299, Vol. 27, no 1-2, p. 25-28Article in journal (Refereed)
    Abstract [en]

    Human basophils became hyporesponsive to anti-IgE when exposed to this agent in the absence of Ca2+ for more than 10 min. The desensitization process proceeded in parallel to the releasing-process. The mechanism of desensitization seems to involve a very early step in the release-reaction, since the response to phospholipase A2 and diolein, agents involved in the release-reaction, was not affected by the desensitization.

  • 11.
    Andersson, Tony
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Nilsson Sköld, Helén
    Kristineberg Marine Research Station,Fiskebäckskil, Sweden.
    Svensson, Samuel
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Phosphoinositide 3-kinase is involved in Xenopus and Labrus melanophore aggregation2003In: Cellular Signalling, ISSN 0898-6568, E-ISSN 1873-3913, Vol. 15, no 12, p. 1119-1127Article in journal (Refereed)
    Abstract [en]

    Melanophores are pigmented cells capable of quick colour changes through coordinated transport of their intracellular pigment granules. We demonstrate the involvement of phosphoinositide 3-kinase (PI3-K) in Xenopus and Labrus aggregation by the use of the PI3-K inhibitor, LY-294002. In Xenopus, wortmannin-insensitive PI3-K was found to be essential for the aggregation, mitogen-activated protein kinase (MAPK) activation and tyrosine phosphorylation of a 280-kDa protein, and for the maintenance of low cyclic adenosine 3′:5′-monophosphate (cAMP) during the aggregated state. Pre-aggregated cells disperse completely to LY-294002 at 50–100 μM, involving a transient elevation in cAMP due to adenylate cyclase (AC) stimulation or to inhibition of cyclic nucleotide phosphodiesterase (PDE). The inactive analogue LY-303511 did not induce dispersion at the same concentrations. PDE4 and/or PDE2 was found to be involved in melanosome aggregation. The similar kinetics of LY-294002 and various PDE inhibitors indicates that the elevation of cAMP might be due to inhibition of PDE. In Labrus melanophores, LY-294002 had a less dramatic effect, probably due to less dependence on PDE in regulation of cAMP levels. In Xenopus aggregation, we suggest that melatonin stimulation of the Mel1c receptor via Gβγ activates PI3-K that, directly or indirectly via MAPK, activates PDE.

  • 12.
    Andersson, Tony P. M.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Melanophore signaling: regulation and application2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Melanophores are pigment-containing cells responsible for quick physiological color changes in lower vertebrates due to redistribution of melanosomes, pigment granules. We have studied melanophores from African clawed frog, Xenopus laevis. Classically, melanosomes can be stimulated to aggregate in the cell center by the hormone melatonin via a process involving activation of the inhibitory Gi/o protein and inhibition of adenylate cyclase/cAMP/protein kinase A pathway. In addition, tyrosine phosphorylations have been shown to be crucial for aggregation. In this thesis, we demonstrate that mitogen-activated protein kinase (MAPK) are activated and phosphoinositol 3-kinase (PI3-K) are involved in melatonininduced aggregation. Inhibition of MAPK kinase or PI3-K inhibits MAPK activation, tyrosine phosphorylation of a 280-kDa protein and aggregation. Further, PI3-K inhibition is less dramatic in fish Labrus melanophores. Together with findings that phosphodiesterase (PDE) 4 and/or PDE2 are involved in keeping the aggregated state in Xenopus, we suggest that active PI3-K via MAPK stimulates PDE, thus lowering cAMP. We also use latrunculin A to induce aggregation via disruption of actin filaments. Kinetic studies indicate that melatonin and latrunculin share final downstream target, possibly inactivate myosin-V leading to melanosome aggregation. As biosensor application, a new computer screen assisted technique suitable for bioassays is demonstrated using melanophores to monitor kinetic responses of melanosome movement and blood plasma sample detection of the asthma drug and ß2 adrenergic agonist formoterol. We also used melanophores to examine the efficacy of enantiomers of formoterol. We confirm that (R;R)-formoterol is more potent than (S;S)-formoterol, in guinea pig tracheal ring preparations, cultured melanophores, and radioligand binding on COS-7 cells, but demonstrate and calculate that (S;S)-formoterol has more efficacy than previously described. Characterization of melanophores are important for biosensor applications, i e to understand mechanisms of drugs, and will probably also increase the knowledge of cell signaling in other cell systems.

    List of papers
    1. Regulation of melanosome movement by MAP kinase
    Open this publication in new window or tab >>Regulation of melanosome movement by MAP kinase
    2003 (English)In: Pigment Cell Research, ISSN 1755-1471, E-ISSN 1755-148X, Vol. 16, no 3, p. 215-221Article in journal (Refereed) Published
    Abstract [en]

    Our objectives were to further characterize the signaling pathways in melatonin-induced aggregation in Xenopus melanophores, specifically to investigate a possible role of mitogen-activated protein kinase (MAPK). By Western blotting we found that melatonin activates MAPK, which precedes melanosome aggregation measured in a microplate reader. Activation of MAPK, tyrosine phosphorylation of a previously described 280-kDa protein, and melanosome aggregation are sensitive to PD98059, a selective inhibitor of MAPK kinase. The MAPK activation is also decreased by the adenylate cyclase stimulant forskolin. In summary, we found that MAPK is activated during melatonin-induced melanosome aggregation. Activation was decreased by an inhibitor of MAPK kinase, and by forskolin. In addition to inhibition of cyclic adenosine 3′,5′-monophosphate (cAMP), reduction in protein kinase A activity (PKA), and activation of protein phosphatase 2A, we suggest that melatonin receptors activate the MAPK cascade and tyrosine phosphorylation of the 280-kDa protein. Although the cAMP/PKA signaling pathway is the most prominent, our data suggest that simultaneous activation of the MAPK cascade is of importance to obtain a completely aggregated state. This new regulatory mechanism of organelle transport by the MAPK cascade might be important in other eukaryotic cells.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26778 (URN)10.1034/j.1600-0749.2003.00048.x (DOI)11383 (Local ID)11383 (Archive number)11383 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2018-08-02Bibliographically approved
    2. Phosphoinositide 3-kinase is involved in Xenopus and Labrus melanophore aggregation
    Open this publication in new window or tab >>Phosphoinositide 3-kinase is involved in Xenopus and Labrus melanophore aggregation
    2003 (English)In: Cellular Signalling, ISSN 0898-6568, E-ISSN 1873-3913, Vol. 15, no 12, p. 1119-1127Article in journal (Refereed) Published
    Abstract [en]

    Melanophores are pigmented cells capable of quick colour changes through coordinated transport of their intracellular pigment granules. We demonstrate the involvement of phosphoinositide 3-kinase (PI3-K) in Xenopus and Labrus aggregation by the use of the PI3-K inhibitor, LY-294002. In Xenopus, wortmannin-insensitive PI3-K was found to be essential for the aggregation, mitogen-activated protein kinase (MAPK) activation and tyrosine phosphorylation of a 280-kDa protein, and for the maintenance of low cyclic adenosine 3′:5′-monophosphate (cAMP) during the aggregated state. Pre-aggregated cells disperse completely to LY-294002 at 50–100 μM, involving a transient elevation in cAMP due to adenylate cyclase (AC) stimulation or to inhibition of cyclic nucleotide phosphodiesterase (PDE). The inactive analogue LY-303511 did not induce dispersion at the same concentrations. PDE4 and/or PDE2 was found to be involved in melanosome aggregation. The similar kinetics of LY-294002 and various PDE inhibitors indicates that the elevation of cAMP might be due to inhibition of PDE. In Labrus melanophores, LY-294002 had a less dramatic effect, probably due to less dependence on PDE in regulation of cAMP levels. In Xenopus aggregation, we suggest that melatonin stimulation of the Mel1c receptor via Gβγ activates PI3-K that, directly or indirectly via MAPK, activates PDE.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26779 (URN)10.1016/S0898-6568(03)00111-6 (DOI)11384 (Local ID)11384 (Archive number)11384 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    3. Myosin V is the rate-determinative step in Xenopus melanophore aggregation
    Open this publication in new window or tab >>Myosin V is the rate-determinative step in Xenopus melanophore aggregation
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    In Xenopus melanophores, melatonin induce melanosome aggregation via activation of its receptor Mel1c, coupled to inhibitory G proteins, adenylate cyclase deactivation, cyclic adenosine 3':5'-monophosphate (cAMP) decrease, protein kinase A inhibition, protein phophatase 2A activation, and serine/threonine dephosphorylations. Myosin V is the motor protein responsible for transporting melanosomes along actin filaments. Myosin V has been demonstrated to be necessary for melanosome dispersion and to keep the dispersed state. We have previously shown that melatonin induce activation of phosphoinositide-3 kinase, mitogen-activated protein kinase and tyrosine phosphorylation of a 280-kDa protein. Here we characterize the kinetics of latrunculin A-induced aggregation, and show that latrunculin A aggregate melanophores with the same kinetics as melatonin. This indicates that the downstream mechanisms might be similar although their primary targets in the cells are totally different. We suggest that both drugs act by inhibiting myosin V, the rate-determinative step for melanosome aggregation. Our data suggest that dynein is not up regulated during aggregation, as previously suggested by others,

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-84527 (URN)
    Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2012-10-12Bibliographically approved
    4. Microplate based biosensing with a computer screen aided technique
    Open this publication in new window or tab >>Microplate based biosensing with a computer screen aided technique
    2003 (English)In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 19, no 1, p. 35-41Article in journal (Refereed) Published
    Abstract [en]

    Melanophores, dark pigment cells from the frog Xenopus laevis, have the ability to change light absorbance upon stimulation by different biological agents. Hormone exposure (e.g. melatonin or α-melanocyte stimulating hormone) has been used here as a reversible stimulus to test a new compact microplate reading platform. As an application, the detection of the asthma drug formoterol in blood plasma samples is demonstrated. The present system utilizes a computer screen as a (programmable) large area light source, and a standard web camera as recording media enabling even kinetic microplate reading with a versatile and broadly available platform, which suffices to evaluate numerous bioassays. Especially in the context of point of care testing or self testing applications these possibilities become advantageous compared with highly dedicated comparatively expensive commercial systems.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-26777 (URN)10.1016/S0956-5663(03)00132-5 (DOI)11382 (Local ID)11382 (Archive number)11382 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
    5. Is effect of (S;S)-formoterol due to contamination of (R;R)-formoterol?
    Open this publication in new window or tab >>Is effect of (S;S)-formoterol due to contamination of (R;R)-formoterol?
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Formoterol is a long acting selective ß2-adrenoceptor (ß2-AR) agonist of the so-called third generation of ß-adrenoceptor agonists. lt also has an onset action comparable to most short acting ß2-AR agonists. Formoterol has two chiral centres making four enantiomers possible. In this study we have examined (R;R)- and (S;S)-formoterol relaxing effect on guinea pig tracheal ring preparations, affinity to human ß2-AR in transfected COS-7 cells and the ability to influence pigment movement in frog melanophores with stable expression of human ß2AR. We also compared single concentration curves versus cumulative concentration curves on guinea pig tracheal preparations. In all three systems the (R;R)-formoterol is the most potent ß2AR agonist compered to (S;S)-formoterol with eudismic ratios ranging from 11 to 75. We also measure and theoretically calculated the effect of (S;S)-formoterol. VVhen the contamination of (R;R)-formoterol was subtracted the (S;S)-formoterol had effect, although approximately 72 times less then (R;R)-formoterol. We conclude that (R;R)-formoterol is the most potent ß2-AR agonist in three different systems and that (S;S)-formoterol posses an ß2-AR effect. We also show that cumulative concentration curves have higher EC50 values compered to single concentration curves and that this might be a consequence of recaptor desensitisation.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-84528 (URN)
    Available from: 2012-10-12 Created: 2012-10-11 Last updated: 2012-10-12Bibliographically approved
  • 13.
    Andersson, Tony P. M.
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Svensson, Samuel P. S.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Myosin V is the rate-determinative step in Xenopus melanophore aggregationManuscript (preprint) (Other academic)
    Abstract [en]

    In Xenopus melanophores, melatonin induce melanosome aggregation via activation of its receptor Mel1c, coupled to inhibitory G proteins, adenylate cyclase deactivation, cyclic adenosine 3':5'-monophosphate (cAMP) decrease, protein kinase A inhibition, protein phophatase 2A activation, and serine/threonine dephosphorylations. Myosin V is the motor protein responsible for transporting melanosomes along actin filaments. Myosin V has been demonstrated to be necessary for melanosome dispersion and to keep the dispersed state. We have previously shown that melatonin induce activation of phosphoinositide-3 kinase, mitogen-activated protein kinase and tyrosine phosphorylation of a 280-kDa protein. Here we characterize the kinetics of latrunculin A-induced aggregation, and show that latrunculin A aggregate melanophores with the same kinetics as melatonin. This indicates that the downstream mechanisms might be similar although their primary targets in the cells are totally different. We suggest that both drugs act by inhibiting myosin V, the rate-determinative step for melanosome aggregation. Our data suggest that dynein is not up regulated during aggregation, as previously suggested by others,

  • 14.
    Andersson, Tony
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Karlsson, Annika M.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Regulation of melanosome movement by MAP kinase2003In: Pigment Cell Research, ISSN 1755-1471, E-ISSN 1755-148X, Vol. 16, no 3, p. 215-221Article in journal (Refereed)
    Abstract [en]

    Our objectives were to further characterize the signaling pathways in melatonin-induced aggregation in Xenopus melanophores, specifically to investigate a possible role of mitogen-activated protein kinase (MAPK). By Western blotting we found that melatonin activates MAPK, which precedes melanosome aggregation measured in a microplate reader. Activation of MAPK, tyrosine phosphorylation of a previously described 280-kDa protein, and melanosome aggregation are sensitive to PD98059, a selective inhibitor of MAPK kinase. The MAPK activation is also decreased by the adenylate cyclase stimulant forskolin. In summary, we found that MAPK is activated during melatonin-induced melanosome aggregation. Activation was decreased by an inhibitor of MAPK kinase, and by forskolin. In addition to inhibition of cyclic adenosine 3′,5′-monophosphate (cAMP), reduction in protein kinase A activity (PKA), and activation of protein phosphatase 2A, we suggest that melatonin receptors activate the MAPK cascade and tyrosine phosphorylation of the 280-kDa protein. Although the cAMP/PKA signaling pathway is the most prominent, our data suggest that simultaneous activation of the MAPK cascade is of importance to obtain a completely aggregated state. This new regulatory mechanism of organelle transport by the MAPK cascade might be important in other eukaryotic cells.

  • 15.
    Aspegren Kendall, Sally
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Pain and Occupational Centre, Pain and Rehabilitation Centre. Linköping University, Faculty of Health Sciences.
    Henriksson, Karl-Gösta
    Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre. Linköping University, Faculty of Health Sciences.
    Hurtig, Ingrid
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Raak, Ragnhild
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Ann
    Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Sören, Birgitta
    Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Wahren, Lis Karin
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre. Linköping University, Faculty of Health Sciences.
    Differences in sensory thresholds in the skin of women with fibromyalgia syndrome: A comparison between ketamine responders and ketamine non-responders2003In: Journal of Musculoskeletal Pain, ISSN 1058-2452, E-ISSN 1540-7012, Vol. 11, no 2, p. 3-9Article in journal (Refereed)
    Abstract [en]

    Objectives: To compare detection and pain thresholds in the skin of female fibromyalgia patients who were either ketamine responders or ketamine nonresponders.

    Methods: Detection thresholds to innocuous warmth, of cold, heat or cold pain, and touch and dynamic touch sensation were determined in the skin. Pressure pain thresholds, local and widespread pain intensity, and pain duration were also registered.

    Results: Ketamine nonresponse was associated with more pronounced hypersensitivity for thermal pain [especially cold pain] than ketamine response.

    Conclusions: Blockade of N-metyl-D-aspartic acid receptors by ketamine and the recording of pain thresholds in the skin, especially for cold pain, might reveal different mechanisms of allodynia.

  • 16.
    Asplund Persson, Anna
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Pharmacological evaluation of the NO/cGMP signalling system2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Platelet activation and inhibition are tightly balanced processes, regulated by various endogenous molecules. In this regard, the endothelium plays a key role in mediating inhibition of platelets by releasing nitric oxide (NO) and cAMP-elevating prostaglandins.

    The present study put emphasis on drugs that activate directly or modulate the NO/cGMP signalling pathway.

    The specific aims were i) to compare two different NO-containing compounds; namely the S-nitrosothiol SNAP and the oxatriazole derivative GEA 3175; ii) to evaluate the mechanism of drug action of the nitrosoamine dephostatin; iii) to investigate cross-talk mechanisms between the NO/cGMP and the cAMP signalling pathways. These studies were perfom1ed using human blood platelets and iliac arteries obtained from pigs.

    The present data revealed that SNAP but not GEA 3175 released detectable amounts of NO. Despite that, both compounds elevated cGMP, inhibited rises in [Ca2+]i and stimulated phosphorylation of vasodilator stimulated phosphoprotein (VASP). Moreover, the results showed that NO/cGMP-induced inhibition of Ca2+ responses, but not NO/cGMP-mediated V ASP phosphorylation, was rapidly desensitised. The results showed that an unstable NO-donor more effectively induced desensitisation.

    Dephostatin, originally characterised as a protein tyrosine phosphatase (PTP) inhibitor, was found to modulate the NO/cGMP signalling in a complex way. More specifically, dephostatin is an effective NO-scavenger and surprisingly, it also serves as a source of NO and thereby induces cGMPmediated vasorelaxation. In platelets, dephostatin abolished NO/cGMP-mediated inhibition of cytosolic Ca2+, but augmented NO/cGMP-induced VASP phosphorylation.

    cGMP-induced inhibition of type 3 phosphodiesterases (PDE3) enhanced adenosine-mediated inhibition of platelets. This effect was of main importance for the suppression of several platelet responses. However, inhibition of Ca2+ influx was another cGMP-specific mechanism contributing to a powerful inhibition of the platelets.

    In conclusion: The present results show that release of NO from drug molecules is not a prerequisite for NO/cGMP-mediated cellular and intracellular responses. On the contrary, drug stability in terms of NO-release appears to be crucial in platelet desensitisation to NO. Therefore it is important to gain more knowledge about the NO/cGMP-signalling pathway regarding future drug design of NO-containing drugs. The findings presented in this thesis suggest that dephostatin can prove to be a very useful tool in this area of research.

    List of papers
    1. Characterisation of GEA 3175 on human platelets: comparison with S-nitroso-N-acetyl-D,L-penicillamine
    Open this publication in new window or tab >>Characterisation of GEA 3175 on human platelets: comparison with S-nitroso-N-acetyl-D,L-penicillamine
    2004 (English)In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 496, no 1-3, p. 1-9Article in journal (Refereed) Published
    Abstract [en]

    By comparing the effect of two nitric oxide (NO)-containing compounds, we found that S-nitroso-N-acetyl-d,l-penicillamine (SNAP), but not GEA 3175 (1,2,3,4-Oxatriazolium,3-(3-chloro-2-metylphenyl)-5-[[(4-methylphenyl)sulfonyl]amino]-, hydroxide inner salt), released NO. Despite this, both drugs elevated cyclic guanosine 3′,5′-monophosphate (cGMP) levels in human platelets. However, SNAP was more effective after short exposure times (5 and 20 s). The compounds also inhibited thrombin-induced rises in cytosolic Ca2+. Time studies revealed that the action of SNAP rapidly declined by increasing the length of incubation (from 5 s to 30 min). This desensibilisation phenomenon mainly involved the release of Ca2+ from intracellular stores. In comparison, GEA 3175-induced inhibition of cytosolic Ca2+ signalling was much more long-lasting. The soluble guanylyl cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reversed the effect of GEA 3175 on cytosolic Ca2+. Consequently, this inhibition depends solely on the increase in cGMP. In summary, differences between GEA 3175 and SNAP were observed in NO releasing, cGMP elevating and Ca2+ suppressive properties.

    Keywords
    NO (Nitric Oxide), cGMP (cyclic guanosine 3′, 5′-monophosphate), Calcium, Aggregation, Platelet, SNAP (S-nitroso-N-acetyl-d, l-penicillamine), GEA 3175
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-20473 (URN)10.1016/j.ejphar.2004.06.002 (DOI)15288569 (PubMedID)
    Available from: 2009-09-09 Created: 2009-09-09 Last updated: 2017-12-13Bibliographically approved
    2. The nitrosoamine dephostatin interacts with nitric oxide/cGMP signalling and modulates cytosolic calcium responses in human platelets
    Open this publication in new window or tab >>The nitrosoamine dephostatin interacts with nitric oxide/cGMP signalling and modulates cytosolic calcium responses in human platelets
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    1 The effects of the nitrosoamine dephostatin on cytosolic Ca2+ and nitric oxide (NO)/cGMP signallings in human platelets were investigated.

    2 Dephostatin has been characterised as a protein tyrosine phosphatase (PTP) inhibitor, and may on that account affect platelet responses. However, western blot analysis revealed that dephostatin (1-100 µM) did not increase tyrosine-specific protein phosphorylation.

    3 Dephostatin dose-dependently (0.003-3 µM) inhibited thrombin-, thrombin-receptor activating peptide-, and ADP-stimulated rises in cytosolic free Ca2+ concentration, [Ca2+]i. in fura-2-loaded platelets. Surprisingly, higher doses of dephostatin (10-30 µM) augmented thrombin-triggered Ca2+ response. This dual action of dephostatin mainly involved modulation of Ca2+ influx.

    4 The results revealed that dephostatin antagonised NO/cGMP- and prostaglandin E1/cAMP-mediated inhibition of [Ca2+]1. The action of the thrornbin-neutralising peptide hirudin was, however, unaffected.

    5 Dephostatin did not affect basal or NO-mediated rises in platelet cGMP content. On the other hand, dephostatin alone directly increased the phosphorylation of ser239 on vasodilator-stimulated phosphoprotein (VASP) and markedly enhanced NO/cGMP-dependent VASP phosphorylation.

    6 Cell functional studies revealed that dephostatin amplified NO-induced inhibition of platelet aggregation. Opposite to that, dephostatin diminished the inhibitory action of NO on phosphatidylserine exposure.

    7 In conclusion, the results revealed that dephostatin affects a wide range of mechanisms involved in Ca2+ homeostasis in platelets. These effects are apparently not due to inhibition of PTPs. However, enhancement of VASP phosphorylation represents another important molecular mechanism of dephostatin. Considering NO signalling, the results indicate that dephostatin may be an excellent tool when elucidating the relative importance of inhibition of Ca2+ versus VASP phosphorylation.

    Keywords
    calcium, cGMP, dephostatin, nitric oxide, platelets, vasodilator-stimulated phosphoprotein
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-82119 (URN)
    Available from: 2012-10-01 Created: 2012-10-01 Last updated: 2012-10-01Bibliographically approved
    3. Dual actions of dephostatin on the nitric oxide/cGMP-signalling pathway in porcine iliac arteries
    Open this publication in new window or tab >>Dual actions of dephostatin on the nitric oxide/cGMP-signalling pathway in porcine iliac arteries
    2005 (English)In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 521, no 1-3, p. 124-132Article in journal (Refereed) Published
    Abstract [en]

    We examined the effects of the nitrosoamine dephostatin on the nitric oxide (NO)/cyclic guanosine 3′,5′-monophosphate (cGMP)-signalling in porcine iliac arteries. Dephostatin has been characterised as a tyrosine phosphatase inhibitor, but Western blot analyses showed that dephostatin did not augment tyrosine phosphorylation of arterial proteins. However, dephostatin relaxed pre-contracted arteries, and this effect was antagonised by the soluble guanylyl cyclase inhibitor 1H[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Furthermore, dephostatin increased the cGMP content and the serine phosphorylation of vasodilator-stimulated phosphoprotein. Dephostatin also inhibited the relaxation induced by acetylcholine and the NO-donor S-nitroso-N-acetyl-penicillamine (SNAP). In contrast, dephostatin did not affect the NO-dependent actions of 1,2,3,4-Oxatriazolium, 3-(3-chloro-2-metylphenyl)-5-[[(4methylphenyl)sulfonyl]amino]-hydroxide inner salt (GEA 3175). Measurement of NO revealed that dephostatin accelerated the consumption of NO. In conclusion, dephostatin exerts dual effects on the NO/cGMP-signalling pathway in iliac arteries. The drug actions included scavenging of NO, but also stimulation of cGMP production. These effects were not related to inhibition of tyrosine phosphatases.

    Keywords
    Dephostatin, GEA 3175, Nitric oxide, Protein phosphorylation, Relaxation, SNAP
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-30909 (URN)10.1016/j.ejphar.2005.08.023 (DOI)16577 (Local ID)16577 (Archive number)16577 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13Bibliographically approved
    4. Cross-talk between adenosine and the oxatriazole derivative GEA 3175 in platelets
    Open this publication in new window or tab >>Cross-talk between adenosine and the oxatriazole derivative GEA 3175 in platelets
    Show others...
    2005 (English)In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 517, no 3, p. 149-157Article in journal (Refereed) Published
    Abstract [en]

    We examined the interplay between adenosine and the nitric oxide (NO)-containing oxatriazole derivative GEA 3175 in human platelets. The importance of cyclic guanosine 3′5′-monophosphate (cGMP)-inhibited phosphodiesterases (PDEs) was elucidated by treating the platelets with adenosine combined with either GEA 3175 or the PDE3-inhibitor milrinone. The drug combinations provoked similar cyclic adenosine 3′5′-monophosphate (cAMP) responses. On the contrary, cGMP levels were increased only in GEA 3175-treated platelets. Both drug combinations reduced P-selectin exposure, platelet adhesion and fibrinogen-binding. However, adenosine together with GEA 3175 was more effective in inhibiting platelet aggregation and ATP release. Thrombin-induced rises in cytosolic Ca2+ were suppressed by the two drug combinations. Adenosine administered with GEA 3175 was, however, more effective in reducing Ca2+ influx.

    In conclusion, the interaction between adenosine and GEA 3175 involves cGMP-mediated inhibition of PDE3. The results also imply that inhibition of Ca2+ influx represent another cGMP-specific mechanism that enhances the effect of adenosine.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-30677 (URN)10.1016/j.ejphar.2005.05.019 (DOI)16282 (Local ID)16282 (Archive number)16282 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13Bibliographically approved
  • 17.
    Asplund Persson, Anna
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, Peter
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Larsson, Jenny
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    The nitrosoamine dephostatin interacts with nitric oxide/cGMP signalling and modulates cytosolic calcium responses in human plateletsManuscript (preprint) (Other academic)
    Abstract [en]

    1 The effects of the nitrosoamine dephostatin on cytosolic Ca2+ and nitric oxide (NO)/cGMP signallings in human platelets were investigated.

    2 Dephostatin has been characterised as a protein tyrosine phosphatase (PTP) inhibitor, and may on that account affect platelet responses. However, western blot analysis revealed that dephostatin (1-100 µM) did not increase tyrosine-specific protein phosphorylation.

    3 Dephostatin dose-dependently (0.003-3 µM) inhibited thrombin-, thrombin-receptor activating peptide-, and ADP-stimulated rises in cytosolic free Ca2+ concentration, [Ca2+]i. in fura-2-loaded platelets. Surprisingly, higher doses of dephostatin (10-30 µM) augmented thrombin-triggered Ca2+ response. This dual action of dephostatin mainly involved modulation of Ca2+ influx.

    4 The results revealed that dephostatin antagonised NO/cGMP- and prostaglandin E1/cAMP-mediated inhibition of [Ca2+]1. The action of the thrornbin-neutralising peptide hirudin was, however, unaffected.

    5 Dephostatin did not affect basal or NO-mediated rises in platelet cGMP content. On the other hand, dephostatin alone directly increased the phosphorylation of ser239 on vasodilator-stimulated phosphoprotein (VASP) and markedly enhanced NO/cGMP-dependent VASP phosphorylation.

    6 Cell functional studies revealed that dephostatin amplified NO-induced inhibition of platelet aggregation. Opposite to that, dephostatin diminished the inhibitory action of NO on phosphatidylserine exposure.

    7 In conclusion, the results revealed that dephostatin affects a wide range of mechanisms involved in Ca2+ homeostasis in platelets. These effects are apparently not due to inhibition of PTPs. However, enhancement of VASP phosphorylation represents another important molecular mechanism of dephostatin. Considering NO signalling, the results indicate that dephostatin may be an excellent tool when elucidating the relative importance of inhibition of Ca2+ versus VASP phosphorylation.

  • 18.
    Asplund Persson, Anna
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, Peter
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lindström, Eva
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Dual actions of dephostatin on the nitric oxide/cGMP-signalling pathway in porcine iliac arteries2005In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 521, no 1-3, p. 124-132Article in journal (Refereed)
    Abstract [en]

    We examined the effects of the nitrosoamine dephostatin on the nitric oxide (NO)/cyclic guanosine 3′,5′-monophosphate (cGMP)-signalling in porcine iliac arteries. Dephostatin has been characterised as a tyrosine phosphatase inhibitor, but Western blot analyses showed that dephostatin did not augment tyrosine phosphorylation of arterial proteins. However, dephostatin relaxed pre-contracted arteries, and this effect was antagonised by the soluble guanylyl cyclase inhibitor 1H[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Furthermore, dephostatin increased the cGMP content and the serine phosphorylation of vasodilator-stimulated phosphoprotein. Dephostatin also inhibited the relaxation induced by acetylcholine and the NO-donor S-nitroso-N-acetyl-penicillamine (SNAP). In contrast, dephostatin did not affect the NO-dependent actions of 1,2,3,4-Oxatriazolium, 3-(3-chloro-2-metylphenyl)-5-[[(4methylphenyl)sulfonyl]amino]-hydroxide inner salt (GEA 3175). Measurement of NO revealed that dephostatin accelerated the consumption of NO. In conclusion, dephostatin exerts dual effects on the NO/cGMP-signalling pathway in iliac arteries. The drug actions included scavenging of NO, but also stimulation of cGMP production. These effects were not related to inhibition of tyrosine phosphatases.

  • 19.
    Asplund Persson, Anna K
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Palmér, Louise
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, Peter
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Characterisation of GEA 3175 on human platelets: comparison with S-nitroso-N-acetyl-D,L-penicillamine2004In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 496, no 1-3, p. 1-9Article in journal (Refereed)
    Abstract [en]

    By comparing the effect of two nitric oxide (NO)-containing compounds, we found that S-nitroso-N-acetyl-d,l-penicillamine (SNAP), but not GEA 3175 (1,2,3,4-Oxatriazolium,3-(3-chloro-2-metylphenyl)-5-[[(4-methylphenyl)sulfonyl]amino]-, hydroxide inner salt), released NO. Despite this, both drugs elevated cyclic guanosine 3′,5′-monophosphate (cGMP) levels in human platelets. However, SNAP was more effective after short exposure times (5 and 20 s). The compounds also inhibited thrombin-induced rises in cytosolic Ca2+. Time studies revealed that the action of SNAP rapidly declined by increasing the length of incubation (from 5 s to 30 min). This desensibilisation phenomenon mainly involved the release of Ca2+ from intracellular stores. In comparison, GEA 3175-induced inhibition of cytosolic Ca2+ signalling was much more long-lasting. The soluble guanylyl cyclase (sGC) inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reversed the effect of GEA 3175 on cytosolic Ca2+. Consequently, this inhibition depends solely on the increase in cGMP. In summary, differences between GEA 3175 and SNAP were observed in NO releasing, cGMP elevating and Ca2+ suppressive properties.

  • 20.
    Asplund Persson, Anna
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Zalavary, Stefan
    Linköping University, Faculty of Health Sciences.
    Lindström, Eva
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Whiss, Per A
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Cross-talk between adenosine and the oxatriazole derivative GEA 3175 in platelets2005In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 517, no 3, p. 149-157Article in journal (Refereed)
    Abstract [en]

    We examined the interplay between adenosine and the nitric oxide (NO)-containing oxatriazole derivative GEA 3175 in human platelets. The importance of cyclic guanosine 3′5′-monophosphate (cGMP)-inhibited phosphodiesterases (PDEs) was elucidated by treating the platelets with adenosine combined with either GEA 3175 or the PDE3-inhibitor milrinone. The drug combinations provoked similar cyclic adenosine 3′5′-monophosphate (cAMP) responses. On the contrary, cGMP levels were increased only in GEA 3175-treated platelets. Both drug combinations reduced P-selectin exposure, platelet adhesion and fibrinogen-binding. However, adenosine together with GEA 3175 was more effective in inhibiting platelet aggregation and ATP release. Thrombin-induced rises in cytosolic Ca2+ were suppressed by the two drug combinations. Adenosine administered with GEA 3175 was, however, more effective in reducing Ca2+ influx.

    In conclusion, the interaction between adenosine and GEA 3175 involves cGMP-mediated inhibition of PDE3. The results also imply that inhibition of Ca2+ influx represent another cGMP-specific mechanism that enhances the effect of adenosine.

  • 21.
    Autelli, Riccardo
    et al.
    Department of Experimental Medicine and Oncology, University of Turin, Italy.
    Ullio, Chiara
    Department of Experimental Medicine and Oncology, University of Turin, Italy.
    Prigione, Elisa
    Department of Experimental Medicine and Oncology, University of Turin, Italy.
    Schiavone, Nicola
    Department of Experimental Medicine and Oncology, University of Florence, Italy.
    Brunk, Ulf
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Capaccioli, Sergio
    Department of Experimental Medicine and Oncology, University of Florence, Italy.
    Baccino, Francesco
    Department of Experimental Medicine and Oncology, University of Turin, Italy.
    Bonelli, Gabriella
    Department of Experimental Medicine and Oncology, University of Turin, Italy.
    Divergent pathways for TNF and C₂-ceramide toxicity in HTC hematoma cells2009In: Biochimica et Biophysica Acta, ISSN 0006-3002, E-ISSN 1878-2434, Vol. 1793, p. 1182-1190Article in journal (Refereed)
    Abstract [en]

    We previously showed that, in the rat hepatoma cell line HTC, TNF brings about a non-caspase-dependent, apoptosis-like process requiring NADPH oxidase activity, an iron-mediated pro-oxidant status, and a functional acidic vacuolar compartment. This process may thus involve mechanisms such as autophagy or relocation of lysosomal enzymes, perhaps secondary to the formation of ceramide by acidic sphingomyelinase. Here we investigated whether ceramide formation contributes to the apoptogenic process. HTC cells were found to be sensitive to exogenous ceramide and significantly protected against TNF by desipramine, an inhibitor of lysosomal acid sphingomyelinase. However, Bcl-2 transfection and Bcl-x(L) upregulation by dexamethasone significantly diminished the apoptogenic effect of ceramide but not that of TNF, suggesting that ceramide is not directly involved in TNF toxicity. Moreover, Bcl-x(L) silencing precluded dexamethasone-induced protection against ceramide and, by itself, induced massive death, demonstrating the strict dependence of HTC cells on Bcl-x(L) for survival also under standard culture conditions.

  • 22. Avliakulov, NK
    et al.
    Lukes, J
    Kajava, AV
    Liedberg, B
    Lundström, I
    Svensson, Samuel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Suramin blocks nucleotide triphosphate binding to ribosomal protein L3 from Trypanoplasma borreli2000In: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 267, no 6, p. 1723-1731Article in journal (Refereed)
    Abstract [en]

    Ribosomal protein L3 (L3) has been demonstrated to participate in formation of the peptidyltransferase center and is essential for its catalytic activity. In the present study we show that L3 is able to bind nucleotide triphosphates with high and specific affinity in vitro. L3 was serendipitously identified by screening of a genomic phage library from a primitive kinetoplastid flagellate Trypanoplasma borreli with the ATPase domain of the topoisomerase II gene as a probe. The cloned gene was overexpressed and purified as a his-tag fusion protein in E. coli. Radioligand binding experiments, using [?-35S]ATP, showed that L3 is able to bind ATP but also GTP and UTP with similar high affinity (IC50 50-100 nM), while it has no ATPase activity. Furthermore, we showed that L3 has more than 500-fold higher affinity for nucleotide triphosphates compared to the corresponding nucleotide monophosphates and diphosphates. Molecular genetic and biochemical analyses allowed us to localize the NTP binding domain of L3 to the N-terminal 296 residues. Suramin, a polysulfonated naphthylamine derivative of urea, known for its chemotherapeutic effects completely inhibited the binding of [?-35S]ATP at subclinical levels. Results obtained with surface plasmon resonance technology showed that suramin both forms weak multimolecular complexes with L3 and bind strongly to L3 in nearly stoichiometric amounts.

  • 23. Axelsson Rosén, Stina
    et al.
    Hägg, Staffan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Eriksson, Andreas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    In vitro effects of antipsychotics on human platelet adhesion and aggregation and plasma coagulation2007In: Clinical and experimental pharmacology & physiology, ISSN 0305-1870, E-ISSN 1440-1681, Vol. 34, no 8, p. 775-780Article in journal (Refereed)
    Abstract [en]

    1. Several studies suggest an association between venous thromboembolism and the use of antipsychotic drugs, especially clozapine, but the biological mechanisms are unknown. It has been suggested that antipsychotic drugs enhance aggregation of platelets and thereby increase the risk of venous thrombosis. The purpose of the present study was to examine the effects of clozapine and its main metabolite, N-desmethyl clozapine, as well as olanzapine, risperidone and haloperidol, on platelet adhesion and aggregation and on plasma coagulation in vitro. 2. Blood was collected from healthy subjects free of medication. Platelet adhesion to different protein surfaces and aggregation were measured in microplates. The coagulation methods of activated partial thromboplastin time (APTT) and prothrombin time were performed in platelet-poor plasma. 3. Clozapine was the only compound that increased platelet adhesion and aggregation and shortened APTT. The effect appeared at therapeutic concentrations and was significant but weak. 4. This weak effect of clozapine on haemostasis may explain, in part, the association of this compound and venous thromboembolism. © 2007 The Authors.

  • 24. Baird, Sarah K
    et al.
    Kurz, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Brunk, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Metallothionein protects against oxidative stress-induced lysosomal destabilization2006In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 394, no 1, p. 275-283Article in journal (Refereed)
    Abstract [en]

    The introduction of apo-ferritin or the iron chelator DFO (desferrioxamine) conjugated to starch into the lysosomal compartment protects cells against oxidative stress, lysosomal rupture and ensuing apoptosis/necrosis by binding intralysosomal redox-active iron, thus preventing Fenton-type reactions and ensuing peroxidation of lysosomal membranes. Because up-regulation of MTs (metallothioneins) also generates enhanced cellular resistance to oxidative stress, including X-irradiation, and MTs were found to be capable of iron binding in an acidic and reducing lysosomal-like environment, we propose that these proteins might similarly stabilize lysosomes following autophagocytotic delivery to the lysosomal compartment. Here, we report that Zn-mediated MT up-regulation, assayed by Western blotting and immunocytochemistry, results in lysosomal stabilization and decreased apoptosis following oxidative stress, similar to the protection afforded by fluid-phase endocytosis of apo-ferritin or DFO. In contrast, the endocytotic uptake of an iron phosphate complex destabilized lysosomes against oxidative stress, but this was suppressed in cells with up-regulated MT. It is suggested that the resistance against oxidative stress, known to occur in MT-rich cells, may be a consequence of autophagic turnover of MT, resulting in reduced iron-catalysed intralysosomal peroxidative reactions. © 2006 Biochemical Society.

  • 25.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Frydén, A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Zalavary, S
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Orselius, Kristina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Platelets enhence neutrophil locomotion: evidence for a role of P-selectin1999In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 59, p. 439-450Article in journal (Refereed)
  • 26.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Grenegård, M
    Leucocyte activation by collagen-stimulated platelets in whole blood2002In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 62, no 6, p. 451-462Article in journal (Refereed)
    Abstract [en]

    Interaction between vascular cells plays an important role in the initial phases of the inflammatory process, but the mechanisms responsible for cell-cell communication are not fully understood. In this study, activation of leucocytes and platelets in heparinized whole blood was assessed using lumi-aggregometry. This technique enables simultaneous measurement of aggregation and oxygen radical production by monitoring impedance and luminol-amplified chemiluminescence (CL), respectively. Collagen induced aggregation and CL, depending on dose, and markedly enhanced subsequent aggregation and CL-response triggered by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe). Collagen stimulation of whole blood down- and upregulated the expression of L-selectin and CD11b, respectively. Monoclonal antibodies against sialyl LewisX and P-selectin caused a pronounced inhibition of the oxidative burst, triggered by collagen itself or by a combination of collagen and fMet-Leu-Phe. Furthermore, the Arg-Gly-Asp-Ser(RGDS)-peptide effectively inhibited collagentriggered aggregation and CL, and the subsequent enhancement of the fMet-Leu-Phe-induced responses. This suggests that fibrinogen plays a part in linking platelet GpIIb/IIIa with CD11b on the leucocyte surface. However, neither anti-CD11b nor the PI-peptide (containing the ?-chain motif in fibrinogen that interacts with CD11b) counteracted the stimulatory effects of activated platelets on leucocyte functions. The selectin- and integrin-antagonizing substances were ineffective on the CL-responses induced by fMet-Leu-Phe itself. This study suggests that, through selectin- and integrin-dependent interaction, activated platelets potentiate leucocyte aggregation and oxygen radical production, which might be important for the outcome of inflammatory reactions.

  • 27.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Orselius, Kristina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology.
    Role of the actin cytoskeleton during respiratory burst in chemoattractant-stimulated neutrophils2006In: Cell Biology International, ISSN 1065-6995, E-ISSN 1095-8355, Vol. 30, no 2, p. 154-163Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to clarify the role of the actin cytoskeleton during chemotactic peptide fMet-Leu-Phe (fMLF)-stimulated respiratory burst in human neutrophil granulocytes. Reactive oxygen species (ROS) was measured as luminol-amplified chemiluminescence (CL) and F-actin content as bodipy phallacidin fluorescence in neutrophils treated with latrunculin B or jasplakinolide, an inhibitor and activator of actin polymerization, respectively. Latrunculin B markedly decreased, whereas jasplakinolide increased, the F-actin content in neutrophils, unstimulated or stimulated with fMLF. Latrunculin B enhanced the fMLF-triggered ROS-production more than tenfold. Jasplakinolide initially inhibited the fMLF-induced CL-response, however, caused a potent second sustained phase (>400% of control). Both actin drugs triggered a substantial CL-response when added 5-25 min after fMLF. This was also valid for chemotactic doses of fMLF, where latrunculin B and jasplakinolide amplified the ROS-production 5-10 times. By using specific signal transduction inhibitors, we found that the NADPH oxidase activation triggered by destabilization of the actin cytoskeleton occurs downstream of phospholipase C and protein kinase C but is mediated by Rho GTPases and tyrosine phosphorylation. In conclusion, rearrangements of the actin cytoskeleton are a prerequisite in connecting ligand/receptor activation, generation of second messengers and assembly of the NADPH oxidase in neutrophil granulocytes. © 2005 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

  • 28.
    Berg, Anna
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Redéen, Stefan
    Linköping University, Department of Biomedicine and Surgery, Surgery. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Ericson, Ann-Charlott
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Sjöstrand, Sven-Erik
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Nitric oxide inhibits gastric acid secretion by increasing intraparietal cell levels of cGMP in isolated human gastric glands2005In: American Journal of Physiology - Gastrointestinal and Liver Physiology, ISSN 0193-1857, E-ISSN 1522-1547, Vol. 289, no 6, p. G1061-G1066Article in journal (Refereed)
    Abstract [en]

    We have previously identified cells containing the enzyme nitric oxide (NO) synthase (NOS) in the human gastric mucosa. Moreover, we have demonstrated that endogenous and exogenous NO has been shown to decrease histamine-stimulated acid secretion in isolated human gastric glands. The present investigation aimed to further determine whether this action of NO was mediated by the activation of guanylyl cyclase (GC) and subsequent production of cGMP. Isolated gastric glands were obtained after enzymatic digestion of biopsies taken from the oxyntic mucosa of healthy volunteers. Acid secretion was assessed by measuring [14C]aminopyrine accumulation, and the concentration of cGMP was determined by radioimmunoassay. In addition, immunohistochemistry was used to examine the localization of cGMP in mucosal preparations after stimulation with the NO donor S-nitroso-N-acetylpenicillamine (SNAP). SNAP (0.1 mM) was shown to decrease acid secretion stimulated by histamine (50 μM); this effect was accompanied by an increase in cGMP production, which was histologically localized to parietal cells. The membrane-permeable cGMP analog dibuturyl-cGMP (db-cGMP; 0.1–1 mM) dose dependently inhibited acid secretion. Additionally, the effect of SNAP was prevented by preincubating the glands with the GC inhibitor 4H-8-bromo-1,2,4-oxadiazolo[3,4-d]benz[b][1,4]oxazin-1-one (10 μM). We therefore suggest that NO in the human gastric mucosa is of physiological importance in regulating acid secretion. Furthermore, the results show that NO-induced inhibition of gastric acid secretion is a cGMP-dependent mechanism in the parietal cell involving the activation of GC.

  • 29.
    Berg, Anna
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Redéen, Stefan
    Linköping University, Department of Biomedicine and Surgery, Surgery. Linköping University, Faculty of Health Sciences.
    Sjöstrand, Sven-Erik
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Ericson, Ann-Charlott
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Effect of nitric oxide on histamine-induced cytological transformations in parietal cells in isolated human gastric glands2007In: Digestive Diseases and Sciences, ISSN 0163-2116, E-ISSN 1573-2568, Vol. 52, no 1, p. 126-136Article in journal (Refereed)
    Abstract [en]

    Previous studies have shown that nitric oxide (NO) inhibits histamine-induced gastric acid secretion in isolated human gastric glands. NO synthase has been found to be present in the human oxyntic mucosa and has been suggested to serve as a paracrine regulator of gastric acid secretion. Histamine stimulation of parietal cells induces cytoskeletal rearrangements, recruitment of H +/K +-ATPase-rich tubulovesicles to the apical membrane and expansion of intracellular canaliculi. The aim of the present study was thus to investigate (i) the effect of an NO donor on histamine-induced cytological transformations and (ii) the influence of increased [Ca 2+] i on NO-induced morphological changes in human parietal cells. Human gastric glands were isolated and subjected to the NO donor SNAP prior to histamine administration. [Ca 2+] i was increased by photolysis of the caged Ca 2+ compound NP-EGTA. The distribution of F-actin, ezrin, and H +/K +-ATPase was assessed by confocal microscopy. Ultrastructural analysis was performed using transmission electron microscopy. SNAP did not influence the histamine-induced translocation of F-actin, ezrin, and H +/K +-ATPase but prevented an increase in the canalicular size. Elevation of [Ca 2+] i in resting cells was found to mimic histamine-induced intraparietal cell transformations; however, NO-induced parietal cell morphology was unaffected by a rise in [Ca 2+] i. These results indicate that NO inhibits secretion of fluid into the canalicular lumen without affecting membrane recruitment and that this effect is Ca 2+-insensitive. © 2006 Springer Science+Business Media, Inc.

  • 30.
    Berg, Cecilia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hammarström, Sven
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Herbertsson, Helena
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lindström, Eva
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Ann-Charlotte
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Söderström, Mats
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Platelet-induced growth of human fibroblasts is associated with an increased expression of 5-lipoxygenase2006In: Thrombosis and Haemostasis, ISSN 0340-6245, Vol. 96, no 5, p. 652-659Article in journal (Refereed)
    Abstract [en]

    Proliferation of fibroblasts is vital for adequate wound healing but is probably also involved in different hyperproliferative disorders such as atherosclerosis and cancer. The regeneration of tissue usually starts with coagulation, involving release of mitogenic and inflammatory factors from activated platelets. This study focuses on the role of eicosanoids in the proliferative effects of platelets on human fibroblasts. We show that the phospholipase A2 inhibitor 7,7-dimethyl-5,8-eicosadienoic acid (DMDA), the combined cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor 5,8,11,14-eicosatetraynoic acid (ETYA) and the LOX inhibitor 5,8,11-eicosatriynoic acid (ETI) block the platelet-induced proliferation of serum starved subconfluent human fibroblasts. Anti-proliferative effects were also obtained by specific inhibition of 5-LOX with 5,6-dehydro arachidonic acid (5,6-dAA), whereas the 12-LOX inhibitor cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) did not affect the platelet-stimulated growth of fibroblasts. The expression of 5-LOX was analyzed by reverse-transcriptase-mediated PCR (RT-PCR), Western blotting and HPLC. 5-LOX message and protein was detected in fibroblasts but not in platelets. Incubation with platelets markedly increased, already after one hour, the expression of 5-LOX in the fibroblast culture. The increased 5-LOX activity was associated with an elevated level of the 5-LOX metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) reaching its maximum after 1-2 hours of co-incubation of fibroblasts and platelets. The 5-HETE production was reduced by the inhibitors DMDA, ETYA and ETI. In conclusion, this study suggests that platelet-stimulated proliferation of fibroblasts is mediated by an increased 5-LOX activity, which supports recent findings indicating a crucial role for this enzyme in proliferative disorders such as atherosclerosis. © 2006 Schattauer GmbH, Stuttgart.

  • 31.
    Björnström, Karin
    et al.
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Eintrei, Christina
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    The difference between sleep and anaesthesia is in the intracellular signal: propofol and GABA use different subtypes of the GABAA receptor β subunit and vary in their interaction with actin2003In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 47, no 2, p. 157-164Article in journal (Refereed)
    Abstract [en]

    Background: Propofol is known to interact with the γ-aminobutyric acidA (GABAA) receptor, however, activating the receptor alone is not sufficient for producing anaesthesia.

    Methods: To compare propofol and GABA, their interaction with the GABAA receptor β subunit and actin were studied in three cellular fractions of cultured rat neurons using Western blot technique.

    Results: Propofol tyrosine phosphorylated the GABAA receptor β2 (MW 54 and 56 kDa) and β3 (MW 57 kDa) subtypes. The increase was shown in both the cytoskeleton (β2(54) and β2(56) subtypes) and the cell membrane (β2(54) and β3 subtypes). Concurrently the 56 kDa β2 subtype was reduced in the cytosol. Propofol, but not GABA, also tyrosine phosphorylated actin in the cell membrane and cytoskeletal fraction. Without extracellular calcium available, the amount of actin decreased in the cytoskeleton, but tyrosine phosphorylation was unchanged. GABA caused increased tyrosine phosphorylation of β2(56) and β3 subtypes in the membrane and both β2 subtypes in the cytoskeleton but no cytosolic tyrosine phosphorylation.

    Conclusion: The difference between propofol and GABA at the GABAA receptor was shown to take place in the membrane, where the β2(54) was increased by propofol and instead the β2(56) subtype was increased by GABA. Only propofol also tyrosine phosphorylated actin in the cell membrane and cytoskeletal fraction. This interaction between the GABAA receptor and actin might explain the difference between anaesthesia and physiological neuronal inhibition.

  • 32.
    Björnström, Karin
    et al.
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Eintrei, Christina
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Volatile anesthetics cause changes in intracellular calcium, tyrosine phosphorylation and actin morphologyManuscript (preprint) (Other academic)
    Abstract [en]

    Background: The cellular effects of anesthetics is poorly known. The GABAA receptor has been suggested as the main target for most anesthetics. In previous studies we have shown that propofol tyresine phosphorylates the GABAA receptor ß subunit, increases intracellular calcium and changes the actin morphology of neurons.

    Aim: To investigate the effects of the volatile anesthetics sevoflurane, isoflurane and nitmus oxide on changes in [Ca2+]i tyrosine phosphorylation and actin morphology in cultured rat neurons.

    Methods: Western blotting (WB) was used to visualize tyrosine phosphorylated proteins. Fluorescence microscopy after rhodamine-phalloidin labelling of actin was used to calculate the number of actin ring structures eaused by sevoflurane. Intracellular calcium was measured with the calcium-binding probe Fura-2 on single cells.

    Results: A protein of approx. 60 kDa increased dose-dependently in tyresine phosphorylation by sevoflurane in the membrane and cytoskeletal fractions, and was simultaneausly reduced in the cytosol. Isoflurane instead increased the tyresine phosphorylation of the same protein in the cytosol with only a slight increase in the membrane and no changes in the cytoskeletal fraction. Nitrous oxide did not cause any changes campared to air in the cytosol and was not detectable in the membrane. However, in the cytoskeletal fraction, the increase in tyrosine phosphorylation was high compared to air. Sevoflurane but not nitrous oxide or air increased the [Ca2+]i· Sevoflurane also eaused actin ring structures with a maximum after 20 minutes.

    Conclusion: Sevoflurane, isoflurane and nitrous oxide all have different signal pathways. The 60 kDa protein is probably the GABAA receptor ß subunit. According to the changes in tyrosine phosphorylation, changes in actin morphology and intracellular calcium, sevoflurane behaves most like the intravenous anesthetic propofol.

  • 33.
    Björnström, Karin
    et al.
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Sjölander, Anita
    Division of Experimental Pathology, Lund University, Malmö, Sweden.
    Schippert, Åsa
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Eintrei, Christina
    Linköping University, Department of Medicine and Care, Anaesthesiology. Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    A tyrosine kinase regulates propofol-induced modulation of the β-subunit of the GABAA receptor and release of intracellular calcium in cortical rat neurones2002In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 175, no 3, p. 227-235Article in journal (Refereed)
    Abstract [en]

    Propofol, an intravenous anaesthetic, has been shown to interact with the β-subunit of the γ-amino butyric acidA (GABAA) receptor and also to cause changes in [Ca2+]i. The GABAA receptor, a suggested target for anaesthetics, is known to be regulated by kinases. We have investigated if tyrosine kinase is involved in the intracellular signal system used by propofol to cause anaesthesia. We used primary cell cultured neurones from newborn rats, pre-incubated with or without a tyrosine kinase inhibitor before propofol stimulation. The effect of propofol on tyrosine phosphorylation and changes in [Ca2+]i were investigated. Propofol (3 μg mL−1, 16.8 μM) increased intracellular calcium levels by 122 ± 34% (mean ± SEM) when applied to neurones in calcium free medium. This rise in [Ca2+]i was lowered by 68% when the cells were pre-incubated with the tyrosine kinase inhibitor herbimycin A before exposure to propofol (P < 0.05). Propofol caused an increase (33 ± 10%) in tyrosine phosphorylation, with maximum at 120 s, of the β-subunit of the GABAA-receptor. This tyrosine phosphorylation was decreased after pre-treatment with herbimycin A (44 ± 7%, P < 0.05), and was not affected by the absence of exogenous calcium in the medium. Tyrosine kinase participates in the propofol signalling system by inducing the release of calcium from intracellular stores and by modulating the β-subunit of the GABAA-receptor.

  • 34.
    Brunk, Ulf
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Growing cells at 40% ambient oxygen conditions them to subsequent oxidative stress2007In: Biogerontology (Dordrecht), ISSN 1389-5729, E-ISSN 1573-6768, Vol. 8, no 5, p. 619-620Article in journal (Other academic)
  • 35.
    Brunk, Ulf
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Eaton, John W
    Molecular Targets Program, James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA.
    Commentary: Peroxide hormesis? A commentary on "Hydrogen peroxide inhibits caspase-dependent apoptosis by inactivating procaspase-9 in an iron-dependent manner": Refers to: Alexandra Barbouti, Christos Amorgianiotis, Evangelos Kolettas, Panagiotis Kanavaros, Dimitrios Galaris Hydrogen peroxide inhibits caspase-dependent apoptosis by inactivating procaspase-9 in an iron-dependent mannerFree Radical Biology and Medicine, Volume 43, Issue 10, 15 November 2007, Pages 1377-13872007In: Free Radical Biology and Medicine, ISSN 0891-5849, Vol. 43, no 10, p. 1372-1373Article in journal (Other academic)
    Abstract [en]

    [No abstract available]

  • 36. Brurok, H
    et al.
    Ardenkjaer-Larsen, J-H
    Hansson, G
    Skarra,
    Berg, K
    Karlsson, I
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Manganese Dipyridoxyl Diphosphate: MRI Contrast Agent with antioxidative and cardioprotective properties.1999In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 254, p. 768-772Article in journal (Refereed)
  • 37.
    Douoalis, Paschalis-Thomas
    et al.
    Ioannina Greece.
    Kotoglou, Plychronis
    Ioannina Greece.
    Tenopoulou, Margarita
    Ioannina Greece.
    Keramisanou, Dimitra
    Ioannina Greece.
    Tzavaras, Theodore
    Ioannina Greece.
    Brunk, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Galaris, Dimitrios
    Ioannina Greece.
    Angelidis, Charalampos
    Ioannina Greece.
    Involvement of heat shock protein-70 in the mechanism of hydrogen peroxide-induced DNA damage: The role of lysosomes and iron2007In: Free Radical Biology & Medicine, ISSN 0891-5849, E-ISSN 1873-4596, Vol. 42, no 4, p. 567-577Article in journal (Refereed)
    Abstract [en]

    Heat shock protein-70 (Hsp70) is the main heat-inducible member of the 70-kDa family of chaperones that assist cells in maintaining proteins functional under stressful conditions. In the present investigation, the role of Hsp70 in the molecular mechanism of hydrogen peroxide-induced DNA damage to HeLa cells in culture was examined. Stably transfected HeLa cell lines, overexpressing or lacking Hsp70, were created by utilizing constitutive expression of plasmids containing the functional hsp70 gene or hsp70-siRNA, respectively. Compared to control cells, the Hsp70-overexpressing ones were significantly resistant to hydrogen peroxide-induced DNA damage, while Hsp70-depleted cells showed an enhanced sensitivity. In addition, the "intracellular calcein-chelatable iron pool" was determined in the presence or absence of Hsp70 and found to be related to the sensitivity of nuclear DNA to H2O2. It seems likely that the main action of Hsp70, at least in this system, is exerted at the lysosomal level, by protecting the membranes of these organelles against oxidative stress-induced destabilization. Apart from shedding additional light on the mechanistic details behind the action of Hsp70 during oxidative stress, our results indicate that modulation of cellular Hsp70 may represent a way to make cancer cells more sensitive to normal host defense mechanisms or chemotherapeutic drug treatment. © 2006 Elsevier Inc. All rights reserved.

  • 38.
    Désilets, Stéphanie
    et al.
    Linköping University, Department of Medicine and Care.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Eriksson, Andreas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Nilsson, Ulrika
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lysophosphatidic acid inhibits ADP-activated platelets2004In: 10th Annual Scandinavian Atherosclerosis Conference and International Meeting,2004, 2004Conference paper (Other academic)
  • 39.
    Edoff, Karin
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Hildebrand, Claes
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Retrograde tracing and neuropeptide immunohistochemistry of sensory neurones projecting to the cartilaginous distal femoral epiphysis of young rats2000In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 299, no 2, p. 193-200Article in journal (Refereed)
    Abstract [en]

    Although cartilage is considered to be devoid of innervation, axons occur in the perichondrium and during development in cartilage canals, thereby having a relatively close spatial relationship to chondroblasts and chondrocytes. The present study locates the source of the sensory innervation of the femoral cartilaginous epiphyses of young rats and investigates whether the neuropeptide calcitonin gene-related peptide (CGRP) can influence chondrocytes. Retrograde tracing from the distal femoral epiphysis of young rats with Fast Blue (FB) showed labelled neuronal profiles in the L2-L5 dorsal root ganglia. Sample countings indicated that 50% of the FB-labelled neuronal profiles were located at the L3 level and 25% at the L4 level. The labelled neurones had diameters of 15-40 µm, with a peak at 25-30 µm. Immunohistochemistry showed that about 50% of the FB-labelled profiles contained CGRP. Together with the finding that CGRP influences bone cells to generate the second messenger cAMP, this result suggested the hypothesis that chondrocytes might be similarly influenced by CGRP. However, stimulation of cartilage slices with CGRP in vitro followed by an assay of the cAMP content did not provide support for this hypothesis. We conclude that primary sensory neurones containing CGRP project to the perichondrium and to cartilage canals of growing cartilage, and that exogenous CGRP does not elevate the cAMP content of cartilage slices in vitro.

  • 40.
    Ekstam Ljusegren, Marie
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    ANP protects myocardium exposed to hypoxia1994Doctoral thesis, comprehensive summary (Other academic)
  • 41. Erdal, H
    et al.
    Berndtsson, M
    Castro, J
    Brunk, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Shoshan, M C
    Linder, S
    Induction of lysosomal membrane permeabilization by compounds that activate p53-independent apoptosis2005In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 102, no 1, p. 192-197Article in journal (Refereed)
    Abstract [en]

    The p53 protein activates cellular death programs through multiple pathways. Because the high frequency of p53 mutations in human tumors is believed to contribute to resistance to commonly used chemotherapeutic agents, it is important to identify drugs that induce p53-independent cell death and to define the mechanisms of action of such drugs. Here we screened a drug library (the National Cancer Institute mechanistic set, 879 compounds with diverse mechanisms of actions) and identified 175 compounds that induced caspase cleavage of cytokeratin-18 in cultured HCT116 colon cancer cells at ≤5 μM. Interestingly, whereas most compounds elicited a stronger apoptotic response in cells with functional p53, significant apoptosis was observed also in p53-null cells. A subset of 15 compounds showing weak or no dependence on p53 for induction of apoptosis was examined in detail. Of these compounds, 11 were capable of activating caspase-3 in enucleated cells. Seven such compounds with nonnuclear targets were found to induce lysosomal membrane permeabilization (LMP). Translocation of the lysosomal proteases cathepsin B and cathepsin D into the cytosol was observed after treatment with these drugs, and apoptosis was inhibited by pepstatin A, an inhibitor of cathepsin D. Apoptosis depended on Bax, suggesting that LMP induced a mitochondrial apoptotic pathway. We conclude that a large number of potential anticancer drugs induce p53-independent apoptosis and that LMP is a mediator of many such responses.

  • 42.
    Eriksson, Andreas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lotfi, Kourosh
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pharmacology.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Enhanced platelet adhesion in essential thrombocythemia assessed by a novel platelet function assay2005In: Congress of the European hematology association,2005, 2005Conference paper (Other academic)
  • 43.
    Eriksson, Andreas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Nilsson, Ulrika
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Adrenaline and lysophosphatidic acid acts synergistically to increase platelet adhesion to Albumin2004In: Annual Scandinavian atherosclerosis conference,2004, 2004Conference paper (Other academic)
  • 44.
    Eriksson, Andreas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Nilsson, Ulrika
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Adrenaline and lysophosphatidic acid acts synergistically to increase platelet adhesion to Albumin2004In: Congress of the European hematology association,2004, 2004Conference paper (Other academic)
  • 45.
    Eriksson, Andreas
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Nilsson, Ulrika
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    The extra cellular ion environment modulates platelet adhesion after lysophosphatidic acid treatment in vitro2006In: XIV International symposium on atherosclerosis,2006, 2006Conference paper (Other academic)
  • 46.
    Eriksson, Therese
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Andersson, Rolf
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Role of ginsenosides and quercetin in anterograde transport of melanosomesManuscript (preprint) (Other academic)
    Abstract [en]

    Panax ginseng is a traditional herb that has been used in the Orient for several thousands of years as a tonic and restorative. Active components of ginseng include ginsenosides, polysaccharides, flavonoids, polyacetylenes, peptides, vitamins, phenols and enzymes, of which the ginsenosides are considered to be the major bioactive constituents. In spite of extensive use, the exact mechanisms of ginseng and its components are still unknown. In the present study we use melanophores from Xenopus laevis to investigate the effects of Panax ginseng extract G115, ginsenosides and the flavonoid quercetin on pigment organelle transport and signalling. Through coordinated transport of their black pigmented granules (melanosomes), melanophores are capable of fast colour changes. The movement is regulated by changes in cyclic adenosine 3’:5’-monophosphate (cAMP) concentration, where a high or low level induce anterograde (dispersion) or retrograde (aggregation) transport respectively, leaving a dark or light cell. Previously we have shown that Panax ginseng induces dispersion of melanosomes. Here, ginsenoside Rc and Rd and the flavonoid quercetin are shown to stimulate an anterograde transport of pigment organelles. When Rc or Rd and quercetin were combined, a significant synergistic increase in dispersion could be seen. Protein kinase C (PKC) inhibitor Myristoylated EGF-R Fragment (651-658) (M-EGF) decreased the anterograde movement stimulated by ginseng and ginsenoside Rc and Rd. We also demonstrate that ginseng, but not ginsenosides or quercetin, induce a concentration-dependent activation of 44/42-mitogen activated protein kinase (MAPK). PKC-inhibition did not affect the MAPK-activation, suggesting a role for PKC in the ginseng- and ginsenoside-induced anterograde transport but not in the activation of MAPK.

  • 47.
    Eriksson, Therese
    et al.
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Svensson, Samuel
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Persson, Karin
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Andersson, Tony
    Landstinget i Kronoberg.
    Andersson, Rolf
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Panax ginseng induces anterograde transport of pigment organelles in Xenopus melanophores2008In: Journal of Ethnopharmacology, ISSN 0378-8741, E-ISSN 1872-7573, Vol. 119, no 1, p. 17-23Article in journal (Refereed)
    Abstract [en]

    Melanophores from Xenopus laevis are pigmented cells, capable of quick colour changes through cyclic adenosine 3':5'-monophosphate (cAMP) coordinated transport of their intracellular pigment granules, melanosomes. In this study we use the melanophore cell line to evaluate the effects of Panax ginseng extract G115 on organelle transport. Absorbance readings of melanophore-coated microplates, Correlate-EIA direct cAMP enzyme immunoassay kit, and western blot were used to measure the melanosome movement and changes in intracellular signalling. We show that Panax ginseng induces a fast concentration-dependent anterograde transport of the melanosomes. No significant increase in the cAMP level was seen and pre-incubation of melanophores with the protein kinase C (PKC) inhibitor EGF-R Fragment 651-658 (M-EGF) only partly decreased the ginseng-induced dispersion. We also demonstrate that Panax ginseng, endothelin-3 (ET-3) and alpha-melanocyte stimulating hormone (MSH) stimulate an activation of mitogen activated protein kinase (MAPK). Pre-incubation with M-EGF decreased the MAPK activity induced by ET-3 and MSH, but again only marginally affected the response of Panax ginseng. Thus, in melanophores we suggest that Panax ginseng stimulates an anterograde transport of pigment organelles via a non-cAMP and mainly PKC-independent pathway.

  • 48. Filippini, D
    et al.
    Svensson, Samuel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lundström, I
    Computer screen as a programmable light source for visible absorption characterization of (bio)chemical assays2003Article in journal (Refereed)
    Abstract [en]

    Visible absorption features suitable for color recognition and micro-plate reading of a standard bioassay are performed by the combination of a computer screen used as a programmable light source and a web camera as detector. The method provides in this way a highly available platform for 'home tests' or 'self-tests', where the requirement is to monitor well defined assays and the use of economical instrumentation is advantageous.

  • 49.
    Filippini, Daniel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Andersson, Tony
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Health Sciences.
    Microplate based biosensing with a computer screen aided technique2003In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 19, no 1, p. 35-41Article in journal (Refereed)
    Abstract [en]

    Melanophores, dark pigment cells from the frog Xenopus laevis, have the ability to change light absorbance upon stimulation by different biological agents. Hormone exposure (e.g. melatonin or α-melanocyte stimulating hormone) has been used here as a reversible stimulus to test a new compact microplate reading platform. As an application, the detection of the asthma drug formoterol in blood plasma samples is demonstrated. The present system utilizes a computer screen as a (programmable) large area light source, and a standard web camera as recording media enabling even kinetic microplate reading with a versatile and broadly available platform, which suffices to evaluate numerous bioassays. Especially in the context of point of care testing or self testing applications these possibilities become advantageous compared with highly dedicated comparatively expensive commercial systems.

  • 50.
    Fägerstam, JP
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Whiss, PA
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Ström, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Gastroenterology and Hepatology. Östergötlands Läns Landsting, MKC - Medicin och kirurgicentrum, GE: gastromed.
    Andersson, RGG
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Expression of platelet P-selectin and detection of soluble P-selectin, NPY and RANTES in patients with inflammatory bowel disease2000In: Inflammation Research, ISSN 1023-3830, E-ISSN 1420-908X, Vol. 49, no 9, p. 466-472Article in journal (Refereed)
    Abstract [en]

    Objective and Design: P-selectin, a membrane glycoprotein which is expressed on activated platelets and endothelial cells, plays a crucial role in the inflammatory response. The main action is adhesion of leukocytes, facilitation of diapedesis and induction of cytokine production from monocytes (MCP-1 and IL-8), mediated via RANTES released from activated platelets. An abnormal platelet activity has been reported in patients with ulcerative colitis (uc) and Crohn's disease (CD), jointly referred to as inflammatory bowel disease (IBD), which could have an aggravating influence on the inflammatory response. In addition, an up-regulation of platelet IL-8 receptors among patients with IBD has been reported. To reveal a presumptuous platelet dysfunction we analysed the expression of platelet surface P-selectin at resting state and after stimulation with thrombin, collagen, epinephrine and interleukin 8 (IL-8), and plasma levels of soluble P-selectin, neuropeptide Y (NPY) and RANTES in patients with IBD. Subjects: Blood from twelve healthy subjects (control group) and twenty-one patients with IBD who had not taken any anti-platelet drugs or steroids were analysed. Methods: Patients were sub-grouped according to disease entity, disease activity and 5ASA medication. Surface P-selectin expression on isolated human platelets and plasma P-selectin, NPY and RANTES were analysed with ELISA. All values are presented as mean ▒ standard error of the mean (SEM). Mann-Whitney U test and Wilcoxon matched rank test were used for statistical analyses. Results: Patients with IBD in remission (n = 9) had higher basal P-selectin expression, 0.38 ▒ 0.04, compared to the control group (n = 12), 0.22 ▒ 0.03, p < 0.01. UC patients (n = 16) showed down-regulation of P-selectin expression after stimulation with IL-8, 0.26 ▒ 0.03 to 0.22 ▒ 0.02, p < 0.05. No significant differences could be observed concerning soluble P-selectin and NPY in plasma. Patients with 5ASA (n = 12) had lower levels of plasma RANTES, 2.39 ▒ 0.06 ╡g/l, compared to the control group (n = 12), 3.29 ▒ 0.19 ╡g/l, p < 0.01, and patients without 5ASA (n = 9), 2.90 ▒ 0.17 ╡g/l, p < 0.05. Conclusions: Patients with IBD in remission have higher basal platelet surface P-selectin expression. An exaggerated platelet activity with increased expression of platelet P-selectin and release of inflammatory mediators such as RANTES, which is chemotactic and induce chemokine production, could have a reinforcing and aggravating influence on the inflammatory response and increase the susceptibility to IBD. In addition IL-8 has a down-regulating effect on platelet surface P-selectin expression and 5ASA medication seems to lower plasma RANTES. If 5ASA is responsible for lowering the concentration of RANTES this could be one of the beneficial outcomes of 5ASA medication.

1234 1 - 50 of 166
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf