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  • 1.
    Ahlen, K.
    et al.
    Åhlén, K., Dept. Med. Biochem. and Microbiol., University of Uppsala, Biomedical Center, SE-751 23 Uppsala, Sweden.
    Ring, P.
    Dept. Med. Biochem. and Microbiol., University of Uppsala, Biomedical Center, SE-751 23 Uppsala, Sweden.
    Tomasini-Johansson, B.
    Dept. Med. Biochem. and Microbiol., University of Uppsala, Biomedical Center, SE-751 23 Uppsala, Sweden, Department of Medicine, University of Wisconsin-Madison, 4285 MSC, 1300 University Ave, Madison, WI 53706, United States.
    Holmqvist, K.
    Dept. Med. Biochem. and Microbiol., University of Uppsala, Biomedical Center, SE-751 23 Uppsala, Sweden, Department of Medical Cell Biology, University of Uppsala, Biomedical Center, SE-751 23 Uppsala, Sweden.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Rubin, K.
    Dept. Med. Biochem. and Microbiol., University of Uppsala, Biomedical Center, SE-751 23 Uppsala, Sweden.
    Platelet-derived growth factor-BB modulates membrane mobility of ß1 integrins2004In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, Vol. 314, no 1, 89-96 p.Article in journal (Refereed)
    Abstract [en]

    Platelet-derived growth factor (PDGF)-BB elicits a migratory response including reorganization of the actin cytoskeleton in different cell types. Here we have investigated the effects of PDGF-BB stimulation on ß 1 integrin containing focal adhesions in human diploid fibroblasts adhered to collagen type I. Stimulation with PDGF-BB dissociated focal adhesions and relocated ß1 integrins from focal adhesions to the periphery of the cells. These changes were rapid and transient in character. Relocation of ß1 integrins was prevented by inhibitors of phosphoinositide-3-kinase and protein kinase C. PDGF-BB stimulated fibroblasts exhibited an increased diffusion coefficient of cell surface ß1 integrins as determined by fluorescence recovery of photobleaching. The cell surface expression of ß1 integrins was not changed after stimulation with PDGF-BB. Our data suggest that PDGF-BB increases the dynamic properties of cell-surface ß1 integrins, which most likely are important for the migratory response elicited by PDGF-BB. © 2003 Elsevier Inc. All rights reserved.

  • 2.
    Aksenova, Vasilisa
    et al.
    Russian Academy of Sciences, St. Petersburg, Russia.
    Turoverova, Lidia
    Russian Academy of Sciences, St. Petersburg, Russia.
    Khotin, Mikhail
    Russian Academy of Sciences, St. Petersburg, Russia.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tulchinsky, Eugene
    University of Leicester, UK.
    Melino, Gerry
    Saint-Petersburg Technological Institute, Russia.
    Pinaev, George P.
    Russian Academy of Sciences, St. Petersburg, Russia.
    Barlev, Nicolai
    Russian Academy of Sciences, St. Petersburg, Russia.
    Tentler, Dmitri
    Russian Academy of Sciences, St. Petersburg, Russia.
    Actin-binding protein alpha-actinin 4 (ACTN4) is a transcriptional co-activator of RelA/p65 sub-unit of NF-kB2013In: OncoTarget, ISSN 1949-2553, Vol. 4, no 2, 362-372 p.Article in journal (Refereed)
    Abstract [en]

    ACTN4 is an actin-binding protein that participates in cytoskeleton organisation. It resides both in the cytoplasm and nucleus and physically associates with various transcription factors. Here, we describe an effect of ACTN4 expression on transcriptional activity of the RelA/p65 subunit of NF-kB. We demonstrate that ACTN4 enhances RelA/p65-dependant expression of c-fos, MMP-3 and MMP-1 genes, but it does not affect TNC, ICAM1 and FN1 expression. Importantly, actin-binding domains of ACTN4 are not critical for the nuclear translocation and co-activation of RelA/p65-dependent transcription. Collectively, our data suggest that in the nucleus, ACTN4 functions as a selective transcriptional co-activator of RelA/p65.

  • 3.
    Aldonyte, R
    et al.
    Vilnius University, Zygimantu 9, Vilnius LT-01102, Lithuania.
    Tunaitis, V
    Vilnius University, Zygimantu 9, Vilnius LT-01102, Lithuania.
    Surovas, A
    Vilnius University, Zygimantu 9, Vilnius LT-01102, Lithuania.
    Suriakaite, K
    Vilnius University, Zygimantu 9, Vilnius LT-01102, Lithuania.
    Jarmalaviciute, A
    Vilnius University, Zygimantu 9, Vilnius LT-01102, Lithuania.
    Magnusson, Karl-Erik
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Pivoriunas, A
    Vilnius University, Zygimantu 9, Vilnius LT-01102, Lithuania.
    Effects of major human antiprotease alpha-1-antitrypsin on the motility and proliferation of stromal cells from human exfoliated deciduous teeth2010In: e-biomed: Journal of Regenerating Medicine, ISSN 1524-8909, Vol. 5, no 4, 633-643 p.Article in journal (Refereed)
    Abstract [en]

    AIM: Intrinsic tissue regeneration mechanisms are still not fully understood. The destruction/reconstruction processes are usually in fine balance; however, this can be easily destroyed, for example in the environment of chronic inflammation. One of the major proteins present at the inflammatory sites is the multifunctional protein alpha-1-antitrypsin (AAT). In this study, potential therapeutic effects of this major human antiprotease on progenitor cells are assessed.

    MATERIALS & METHODS: Stromal cells from human exfoliated deciduous teeth (SHEDs) were used, which are similar to the mesenchymal stromal cells isolated from other tissues. SHEDs were cultivated in the presence of subphysiological, physiological and inflammatory concentrations of AAT, and their proliferation and motility traits were assayed. Some intracellular signaling pathways, AAT internalization by SHEDs and their matrix metalloprotease profile were studied in parallel.

    RESULTS: Physiologic and inflammatory concentrations of AAT significantly increased the cell proliferation rate, induced phosphorylation of several key protein kinases and increased the amount of secreted active gelatinases. Moreover, cells exposed to physiologic and inflammatory levels of AAT were able to invade and migrate more efficiently. Subphysiologic AAT levels did not change cell behavior significantly.

    CONCLUSION: AAT at physiologic and inflammatory concentrations positively modulates the proliferation and motility of SHEDs in vitro. These results suggest the importance of AAT in the maintenance and regulation of tissue progenitor cells in vivo.

  • 4.
    Amin, M.
    et al.
    CIHR Group in Matrix Dynamics and Dental Research Institute, University of Toronto, Toronto, ON, Canada.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Kapus, A.
    Department of Surgery, St. Michael's Hospital Research Institute, Toronto, ON, Canada.
    Glogauer, M.
    CIHR Group in Matrix Dynamics and Dental Research Institute, University of Toronto, Toronto, ON, Canada.
    Ellen, R.P.
    CIHR Group in Matrix Dynamics and Dental Research Institute, University of Toronto, Toronto, ON, Canada, CIHR Group in Matrix Dynamics, University of Toronto, Faculty of Dentistry, 124 Edward Street, Toronto, ON M5G 1G6, Canada.
    Treponema denticola Msp-deduced peptide conjugate, P34BSA, promotes RhoA-dependent actin stress fiber formation independent of its internalization by fibroblasts2008In: Cell Motility and the Cytoskeleton, ISSN 0886-1544, Vol. 65, no 5, 406-421 p.Article in journal (Refereed)
    Abstract [en]

    P34BSA, a BSA conjugate of a synthetic 10-mer peptide deduced from Treponema denticola major outer sheath protein (Msp), stabilizes actin filaments in fibroblasts and retards cell motility. We reported previously that it is internalized by cells, binds and bundles actin filaments in vitro, and activates RhoA, yet, its site and mechanism of action were not defined. We have assessed P34BSA's modes of interaction with and signaling to fibroblasts. At 4°C, P34BSA was not internalized, but it bound to the plasma membrane and promoted actin stress fiber formation at ~80% capacity compared with 37°C controls, casting doubt that cellular uptake is a critical step for its cytoskeleton-stabilizing property. In Rho G-LISA™ and co-immunoprecipitation assays, P34BSA was found to activate RhoA, even at 4°C, to promote its interaction with guanosine nucleotide exchange factor p114RhoGEF. It also caused phosphorylation of cofilin. Upon RhoA inhibition, either by C3 transferase RhoA inhibitor or by transfection with a dominant negative RhoA construct, P34BSA did not achieve the stress fiber formation seen with P34BSA alone. By inhibiting phosphatidylinositol-3 kinase (PI 3-K) with LY294002, the P34BSA effects were completely blocked. Depletion of cholesterol with methyl-ß-cyclodextrin (MßCD) partially inhibited P34BSA signaling via the plasma membrane to the cytoskeleton. This suggests that multivalent P34BSA activation of lipid raft components requires active PI 3-K, and initiates the pathway through a RhoGEF and RhoA, which mediates stress fiber formation in fibroblasts. Hence, P34BSA may represent a novel tool to investigate RhoA-dependent processes, such as remodeling filamentous actin in eukaryotic cells. © 2008 Wiley-Liss, Inc.

  • 5.
    Andersson, Cecilia
    et al.
    Swedish Institute Communicable Disease Control.
    Henriksson, Sara
    Uppsala University.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nilsson, Mats
    Uppsala University.
    Mirazimi, Ali
    Swedish Institute Communicable Disease Control.
    In situ rolling circle amplification detection of Crimean Congo hemorrhagic fever virus (CCHFV) complementary and viral RNA2012In: Virology, ISSN 0042-6822, E-ISSN 1096-0341, Vol. 426, no 2, 87-92 p.Article in journal (Refereed)
    Abstract [en]

    Crimean Congo hemorrhagic fever virus (CCHFV) is a human pathogen that causes a severe disease with high fatality rate for which there is currently no specific treatment. Knowledge regarding its replication cycle is also highly limited. In this study we developed an in situ technique for studying the different stages during the replication of CCHFV. By integrating reverse transcription, padlock probes, and rolling circle amplification, we were able to detect and differentiate between viral RNA (vRNA) and complementary RNA (cRNA) molecules, and to detect viral protein within the same cell. These data demonstrate that CCHFV nucleocapsid protein (NP) is detectable already at 6 hours post infection in vRNA- and cRNA-positive cells. Confocal microscopy showed that cRNA is enriched and co-localized to a large extent with NP in the perinuclear area, while vRNA has a more random distribution in the cytoplasm with only some co-localize with NP. However, vRNA and cRNA did not appear to co-localize directly.

  • 6.
    Andersson, I.
    et al.
    Ctr. Microbiological Preparedness, Swed. Inst. for Infect. Dis. Control, SE-171 82 Solna, Sweden.
    Bladh, L.
    Ctr. Microbiological Preparedness, Swed. Inst. for Infect. Dis. Control, SE-171 82 Solna, Sweden.
    Mousavi-Jazi, M.
    Ctr. Microbiological Preparedness, Swed. Inst. for Infect. Dis. Control, SE-171 82 Solna, Sweden.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Lundkvist, A.
    Lundkvist, Å., Ctr. Microbiological Preparedness, Swed. Inst. for Infect. Dis. Control, SE-171 82 Solna, Sweden, MTC/Karolinska Institutet, SE-171 77 Stockholm, Sweden.
    Haller, O.
    Department of Virology, University of Freiburg, D-79008 Freiburg, Germany.
    Mirazimi, A.
    Ctr. Microbiological Preparedness, Swed. Inst. for Infect. Dis. Control, SE-171 82 Solna, Sweden.
    Human MxA Protein Inhibits the Replication of Crimean-Congo Hemorrhagic Fever Virus2004In: Journal of Virology, ISSN 0022-538X, Vol. 78, no 8, 4323-4329 p.Article in journal (Refereed)
    Abstract [en]

    Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the genus Nairovirus within the family Bunyaviridae and is the causative agent of severe hemorrhagic fever. Despite increasing knowledge about hemorrhagic fever viruses, the factors determining their pathogenicity are still poorly understood. The interferon-induced MxA protein has been shown to have an inhibitory effect on several members of the Bunyaviridae family, but the effect of MxA against CCHFV has not previously been studied. Here, we report that human MxA has antiviral activity against CCHFV. The yield of progeny virus in cells constitutively expressing MxA was reduced up to 1,000-fold compared with control cells, and accumulation of viral genomes was blocked. Confocal microscopy revealed that MxA colocalizes with the nucleocapsid protein (NP) of CCHFV in the perinuclear regions of infected cells. Furthermore, we found that MxA interacted with NP by using a coimmunoprecipitation assay. We also found that an amino acid substitution (E645R) within the C-terminal domain of MxA resulted in a loss of MxA antiviral activity and, concomitantly, in the capacity to interact with CCHFV NP. These results suggest that MxA, by interacting with a component of the nucleocapsid, prevents replication of CCHFV viral RNA and thereby inhibits the production of new infectious virus particles.

  • 7.
    Andersson, Kerstin
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Majeed, Meytham
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Stendahl, Olle
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Fällman, Maria
    Department of Cell and Molecular Biology, University of Umeå, Umeå, Sweden.
    Yersinia pseudotuberculosis-induced calcium signaling in neutrophils is blocked by the virulence effector YopH1999In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 67, no 5, 2567-2574 p.Article in journal (Refereed)
    Abstract [en]

    Pathogenic species of the genus Yersinia evade the bactericidal functions of phagocytes. This evasion is mediated through their virulence effectors, Yops, which act within target cells. In this study we investigated the effect of Yersinia pseudotuberculosis on Ca 2+ signaling in polymorphonuclear neutrophils. The intracellular free calcium concentration in single adherent human neutrophils was monitored during bacterial infection and, in parallel, the encounter between the bacteria and cells was observed. When a plasmid-cured strain was used for infection, adherence of a single bacterium to the cellular surface induced a β 1 integrin-dependent transient increase in the intracellular concentration of free calcium. This was, however, not seen with Yop-expressing wild-type bacteria, which adhered to the cell surface without generating any Ca 2+ signal. Importantly, the overall Ca 2+ homeostasis was not affected by the wild-type strain; the Ca 2+ signal mediated by the G-protein-coupled formyl-methionyl-leucyl- phenylalanine receptor was still functioning. Hence, the blocking effect was restricted to certain receptors and their signaling pathways. The use of different Yop mutant strains revealed that the protein tyrosine phosphatase YopH was responsible for the inhibition. This virulence determinant has previously been implicated in very rapid Yersinia-mediated effects on target cells as the key effector in the blockage of phagocytic uptake. The present finding, that Y. pseudotuberculosis, via YopH, specifically inhibits a self- induced immediate-early Ca 2+ signal in neutrophils, offers more-detailed information concerning the effectiveness of this virulence effector and implies an effect on Ca 2+-dependent, downstream signals.

  • 8.
    Babakov, V.N.
    et al.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Petukhova, O.A.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Turoverova, L.V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Kropacheva, I.V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Tentler, D.G.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Bolshakova, A.V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    Podolskaya, E.P.
    Laboratory of Environmental and Biomedical Mass Spectrometry, Institute for Analytical Instrumentation, St. Petersburg, 198103, Russian Federation.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Pinaev, G.P.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russian Federation.
    RelA/NF-?B transcription factor associates with a-actinin-42008In: Experimental Cell Research, ISSN 0014-4827, Vol. 314, no 5, 1030-1038 p.Article in journal (Refereed)
    Abstract [en]

    The NF-?B/RelA family of transcription factors regulates inducible transcription of a large number of genes in response to diverse stimuli. Little is known, however, about the location of NF-?B in the cytoplasm and the transport mechanism to the nucleus. We found that NF-?B is associated with the actin-binding protein a-actinin-4. NF-?B and a-actinin-4 co-localized along actin stress fibers and in membrane lamellae in A431 cells. After a 30-min stimulation with EGF or TNF-a, a-actinin-4 and p65 were found in the nucleus. Disruption of cytoskeleton by cytochalasin D prior to treatment with TNF-a led to increase of p65 nuclear translocation. Antibodies to p65 subunit of NF-?B co-immunoprecipitated a-actinin-4 from A431 cell lysates and nuclear extracts, but a-actinin-1 and ß-actin were not found in the precipitates. Affinity chromatography experiments displayed that p65 and p50 subunits of NF-?B can bind to matrix-bound chicken gizzard a-actinin. We suggest that the a-actinin-4 is important for the NF-?B nuclear translocation and its functions inside the nucleus. © 2007 Elsevier Inc. All rights reserved.

  • 9. Baniulis, Danas
    et al.
    Burritt, James B
    Taylor, Ross M
    Dinauer, Mary C
    Heyworth, Paul G
    Parkos, Charles A
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Jesaitis, Algirdas J
    Monoclonal antibody CL5 recognizes the amino terminal domain of human phagocyte flavocytochrome b558 large subunit, gp91phox2005In: European Journal of Haematology, ISSN 0902-4441, Vol. 74, no 4, 337-347 p.Article in journal (Refereed)
    Abstract [en]

    Human phagocyte flavocytochrome b558 (Cytb) is a heterodimeric integral membrane protein that serves as the electron transferase of the β-nicotinamide adenine dinucleotidephosphate, reduced (NADPH)-oxidase, an enzyme complex important in the host defense function of phagocytic cells. In this study, we report the characterization of monoclonal antibody (mAb) CL5 that is specific for the large subunit, gp91phox, of the oxidase protein. This antibody recognizes gp91phox by immunoblot analysis of membrane extracts and samples of the immunopurified gp91phox/p22 phox heterodimer, prepared on anti-p22phox affinity matrices. Phage display analysis confirmed this specificity, indicating that the CL5 epitope contains the region 135-DPYSVALSELGDR of gp91phox. The antibody was used to probe for the presence of gp91phox in membrane preparations from neutrophils of patients with nine genetically distinct forms of X-linked chronic granulomatous disease (CGD). The causative mutations included missense errors as well as nonsense errors that result in premature termination of gp91phox synthesis. Analysis of the CGD samples by immunoblotting indicated that CL5 recognizes only the full-length wild-type and two missense mutations, consistent with the absence of stable short gp91 phox peptide expression in CGD neutrophils. Interestingly, CL5 was also shown to be cross-reactive with cytosolic and membrane-bound gelsolin, identified by purification, mass spectrometry and immunoblot analysis. CL5 probably cross-reacts with the sequence 771-DPLDRAMAEL in the C-terminus of gelsolin. We conclude that mAb CL5 is a useful probe for detection of full length and possibly truncated N-terminal fragments of gp91phox from membranes of Cytb-producing cells. © Blackwell Munksgaard 2005.

  • 10. Baniulis, Danas
    et al.
    Nauseef, William M
    Burritt, James B
    Taylor, Ross M
    Heyworth, Paul G
    Dinauer, Mary C
    Bumelis, Vladas A
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Jesaitis, Algirdas J
    Unusual polyclonal anti-gp91phox peptide antibody interactions with X-linked chronic granulomatous disease-derived human neutrophils are not from compensatory expression of Nox proteins 1, 3, or 42005In: European Journal of Haematology, ISSN 0902-4441, Vol. 74, no 3, 241-249 p.Article in journal (Refereed)
    Abstract [en]

    To obtain topological information about human phagocyte flavocytochrome b558 (Cytb), rabbit anti-peptide antibodies were raised against synthetic peptides mimicking gp91phox regions: 1-9 (MGN), 30-44 (YRV), 150-159 (ESY), 156-166 (ARK), 247-257 (KIS-1, KIS-2). Following affinity purification on immobilized peptide matrices, all antibodies but not prebleed controls recognized purified detergent-solubilized Cytb by enzyme-linked immunosorbent assay (ELISA). Affinity-purified antibodies recognizing KIS, ARK and ESY but not YRV, MGN or prebleed IgG specifically detected gp91phox in immunoblot analysis. Antibodies recognizing MGN, ESY, ARK and KIS but not YRV or the prebleed IgG fraction labeled intact normal neutrophils. Surprisingly, all antibodies, with the exception of YRV and pre-immune IgG controls, bound both normal and Cytb-negative neutrophils from the obligate heterozygous mother of a patient with X-linked chronic granulomatous disease (X-CGD) and all neutrophils from another patient lacking the gp91phox gene. Further immunochemical examination of membrane fractions derived from nine genetically unrelated patients with X-CGD, using an antibody that recognizes other Nox protein family members, suggests that the unusual reactivity observed does not reflect the compensatory expression of gp91phox homologs Nox1, 3 or 4. These results suggest that an unusual surface reactivity exists on neutrophils derived from X-linked chronic granulomatous disease patients that most likely extends to normal neutrophils as well. The study highlights the need for caution in interpreting the binding of rabbit polyclonal antipeptide antibodies to human neutrophils in general and, in the specific case of antibodies directed against Cytb, the need for Cytb-negative controls.

  • 11. Bengtsson, T.
    et al.
    Jaconi, ME
    Gustafsson, Mikael
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Theler, JM
    Lew, DP
    Stendahl, Olle
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Actin dynamics in human neutrophils during adhesion and phagocytosis is controlled by changes in intracellular free calcium1993In: European Journal of Cell Biology, ISSN 0171-9335, E-ISSN 1618-1298, Vol. 62, no 1, 19-58 p.Article in journal (Refereed)
    Abstract [en]

    The role of changes in cytosolic free calcium concentration ([Ca2+]i) in the assembly and disassembly of actin during adhesion and phagocytosis was evaluated. Rhodamine-phalloidin staining combined with quantitative fluorescence and confocal laser scanning microscopy was used to measure local F-actin changes in single adherent human neutrophils phagocytosing yeast particles on different surfaces and under different calcium conditions. Cells were suspended in a) calcium-containing medium (CCM) or b) calcium-free medium (CFM) or c) were first depleted of calcium (i.e., MAPT/AM-loaded in CFM) and then suspended in CFM (MAPT). In parallel, local [Ca2+]i changes were monitored using a fura-2 ratio imaging system. In CCM or CFM, attachment to the substrate and formation of pseudopods around a yeast particle generated, within a few seconds, rises in [Ca2+]i, both around the phagosome and in the cell body. During continued phagocytosis, [Ca2+]i was more elevated around the phagosome compared to the rest of the cell. No [Ca2+]i fluctuations were observed in MAPT cells. Adhesion and phagocytosis led to a several-fold increase in F-actin. The increase was transient in cells in CCM and CFM, but remained high in Ca-depleted neutrophils. A distinct ring of F-actin was formed around a phagosome with a yeast particle. Twenty min after ingestion the amount of this actin decreased more than 50% in CCM and CFM cells but increased by 40 to 100% in MAPT cells. The accumulation of F-actin in MAPT cells was reduced to resting levels by adding Ca2+ and ionomycin after ingestion. This treatment reestablished the periphagosomal [Ca2+]i rises, as observed in CCM cells. In conclusion, the present study shows that the actin polymerization, occurring in human neutrophils during adhesion and phagocytosis, is not influenced by changes in [Ca2+]i, whereas the subsequent depolymerization is. The accumulation of actin filaments around the phagosome in calcium-depleted cells could be involved in the inhibition of phagolysosome fusion seen in the absence of [Ca2+]i changes (Jaconi et al., J. Cell Biol. 110, 1555-1564 (1990)). This suggests that the actin network, controlled by [Ca2+]i, regulates the movement of granules during phagocytosis.

  • 12.
    Bertilsson, PM
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Olsson, P
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Cytokines influence mRNA expression of cytochrome P450 3A4 and MDRI in intestinal cells.2001In: Journal of Pharmaceutical Sciences, ISSN 0022-3549, Vol. 90, 638-646 p.Article in journal (Refereed)
  • 13.
    Bialowas, Sonja
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Hagbom, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Karlsson, Thommie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-­Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Intracellularly expressed rotavirus NSP4 stimulates release of serotonin (5-HT) from human enterochromaffin cellsManuscript (preprint) (Other academic)
    Abstract [en]

    Rotavirus (RV) is associated with diarrhoea and vomiting, but the mechanisms behind these symptoms remain unresolved. While RV have been shown to infect and stimulate secretion of serotonin (5-hydroxytryptamine; 5-HT) from human enterochromaffin (EC) cells and to infect EC cells in the small intestine of mice, it remains to identify which intracellularly expressed viral protein (VP) being responsible for this novel property.

    To address this issue, human EC cells were transfected with small interfering RNA (siRNA) targeting the structural (VP4, VP6 and VP7) and the non-structural protein 4 (NSP4) followed by infection with Rhesus rotavirus (RRV). siRNA specific to NSP4 (siRNANSP4) significantly attenuated secretion of 5-HT compared to siRNAVP4, siRNAVP6 , siRNAVP7 and non-targeting (Nt) siRNAnt. Intracellular calcium clamping with BABTA/AM showed that intracellularly expressed NSP4-stimulated secretion of 5-HT from EC cells was calcium-dependent. Furthermore RV down-regulated the 5-HT transporter (SERT) mRNA in ileum but not tryptophan hydroxylase 1 (TPH1) mRNA the rate-limiting enzyme for 5-HT synthesis. The unaffected expression of TPH1 mRNA in the intestinal segments suggests that release of 5- HT primarily originates from pre-made 5-HT rather than from newly synthesised 5-HT mRNA. Moreover, down-regulation of SERT mRNA in ileum presumably resulted in reduced re- uptake of 5-HT by SERT to EC cells and thus increased extracellular 5-HT in the small intestine. Moreover, 7/7 infant mice responded following intraperitoneal administration of 5-HT with rapid (<30 min) diarrhoea in dose-dependent manner. In the light of these results and the fact that both 5-HT and NSP4 can induce diarrhoea in mice, a disease mechanism to RV diarrhoea is proposed.

  • 14.
    Bialowas, Sonja
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Hagbom, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Karlsson, Thommie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Rotavirus and Serotonin Cross-Talk in Diarrhoea2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 7, e0159660- p.Article in journal (Refereed)
    Abstract [en]

    Rotavirus (RV) has been shown to infect and stimulate secretion of serotonin from human enterochromaffin (EC) cells and to infect EC cells in the small intestine of mice. It remains to identify which intracellularly expressed viral protein(s) is responsible for this novel property and to further establish the clinical role of serotonin in RV infection. First, we found that siRNA specifically silencing NSP4 (siRNA(NSP4)) significantly attenuated secretion of serotonin from Rhesus rotavirus (RRV) infected EC tumor cells compared to siRNA(VP4), siRNA(VP6) and siRNA(VP7). Second, intracellular calcium mobilization and diarrhoeal capacity from virulent and avirulent porcine viruses correlated with the capacity to release serotonin from EC tumor cells. Third, following administration of serotonin, all (10/10) infants, but no (0/8) adult mice, responded with diarrhoea. Finally, blocking of serotonin receptors using Ondansetron significantly attenuated murine RV (strain EDIM) diarrhoea in infant mice (2.9 vs 4.5 days). Ondansetron-treated mice (n = 11) had significantly (p amp;lt; 0.05) less diarrhoea, lower diarrhoea severity score and lower total diarrhoea output as compared to mock-treated mice (n = 9). Similarly, Ondansetron-treated mice had better weight gain than mock-treated animals (p amp;lt; 0.05). A most surprising finding was that the serotonin receptor antagonist significantly (p amp;lt; 0.05) also attenuated total viral shedding. In summary, we show that intracellularly expressed NSP4 stimulates release of serotonin from human EC tumor cells and that serotonin participates in RV diarrhoea, which can be attenuated by Ondansetron.

  • 15.
    Bolshakova, A.
    et al.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg, 194064, Russian Federation.
    Petukhova, O.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg, 194064, Russian Federation.
    Turoverova, L.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg, 194064, Russian Federation.
    Tentler, D.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg, 194064, Russian Federation.
    Babakov, V.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg, 194064, Russian Federation.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Pinaev, G.
    Department of Cell Cultures, Institute of Cytology, Tikhoretsky Avenue 4, St. Petersburg, 194064, Russian Federation.
    Extra-cellular matrix proteins induce re-distribution of a-actinin-1 and a-actinin-4 in A431 cells2007In: Cell Biology International, ISSN 1065-6995, Vol. 31, no 4 SPEC. ISS., 360-365 p.Article in journal (Refereed)
    Abstract [en]

    Alpha-actinins are actin-binding proteins of non-muscle cells, which can participate in the regulation of transcription factor activity. We describe the distribution of a-actinin-1 and -4 depending on different actin cytoskeleton formed as a result of cell adhesion to extracellular matrix proteins, such as fibronectin and laminin 2/4. Immunofluorescent studies show a difference in the distribution of a-actinin and -4. Both isoforms localise along stress-fibres, but a-actinin-1 localises in the perinuclear region more abundantly than a-actinin-4. Western blot analysis demonstrated existence of truncated forms of both isoforms. Truncated a-actinin-1 appears in cells spread on fibronectin or laminin. Cell spreading also correlated with more tight association of a-actinin-4 with chromatin. Basing on our previous finding of an interaction of a-actinin-4 with p65 subunit of the NF-?B, we checked the possible influence of immobilised ligands on its redistribution in nuclear complexes containing p65. a-Actinin-4 seems to be present in some but not all nuclear complexes containing p65. Immobilised ligands may affect the interaction of a-actinin-4/p65 complexes with chromatin. The data suggest that adhesion to extra-cellular matrix may interfere in cellular reactions mediated by a-actinin-1 and -4. © 2007 International Federation for Cell Biology.

  • 16.
    Bolshakova, Anastasia
    et al.
    Russian Academic Science, Russia .
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Pinaev, George
    Russian Academic Science, Russia .
    Petukhova, Olga
    Russian Academic Science, Russia .
    Functional compartmentalisation of NF-B-associated proteins in A431 cells2013In: Cell Biology International, ISSN 1065-6995, E-ISSN 1095-8355, Vol. 37, no 4, 387-396 p.Article in journal (Refereed)
    Abstract [en]

    NF-B proteins belong to a family of ubiquitous transcription factors involved in a number of cellular responses. While the pathways of NF-B activation and input into the regulation of gene activity have been comprehensively investigated, its cytoplasmic functions are poorly understood. In this study we addressed effects of the compartmentalisation of NF-B proteins RelA/p65 and p50 in relation to the inhibitor IB-, using fibronectin (FN) and epidermal growth factor (EGF) for environmental stimulation of epidermoid carcinoma A431 cells. We thus assessed the presence of NF-B family proteins in the cytosol, membrane, nuclear and cytoskeletal fractions with a special attention to the cytoskeletal fraction to define whether NF-B was active or not. Sub-cellular fractionation demonstrated that the proportion of RelA/p65 differed in diverse sub-cellular fractions, and that the cytoskeleton harboured about 7% thereof. Neither the nuclear nor the cytoskeleton fraction did contain IB-. The cytoskeleton binding of RelA/p65 and p50 was further confirmed by co-localisation and electron microscopy data. During 30-min EGF stimulation similar dynamics were found for RelA/p65 and IB- in the cytosol, RelA/p65 and p50 in the nucleus and p50 and IB- in the membrane. Furthermore, EGF stimulation for 30min resulted in a threefold accumulation of RelA/p65 in cytoskeletal fraction. Our results suggest that nuclear-, membrane- and cytoskeleton-associated NF-B are dynamic and comprise active pools, whereas the cytoplasmic is more constant and likely non-active due to the presence of IB-. Moreover, we discovered the existence of a dynamic, IB--free pool of RelA/p65 associated with cytoskeletal fraction, what argues for a special regulatory role of the cytoskeleton in NF-B stimulation.

  • 17.
    Bolshakova, Anastayia
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Russian Academic Science, Russia; St Petersburg State Polytech University, Russia.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Pinaev, George
    Russian Academic Science, Russia.
    Petukhova, Olga
    Russian Academic Science, Russia.
    EGF-induced dynamics of NF-kappa B and F-actin in A431 cells spread on fibronectin2015In: Histochemistry and Cell Biology, ISSN 0948-6143, E-ISSN 1432-119X, Vol. 144, no 3, 223-235 p.Article in journal (Refereed)
    Abstract [en]

    To evaluate the role of actin cytoskeleton in the regulation of NF-kappa B transcription factor, we analyzed its involvement in the intracellular transport and nuclear translocation of the NF-kappa B RelA/p65 subunit in A431 epithelial cells stimulated with fibronectin and EGF. Live cell imaging and confocal microscopy showed that EGF activated the movement of RelA/p65 in the cytoplasm. Upon cell adhesion to fibronectin, RelA/p65 concentrated onto stress fibers, and EGF stimulated its subsequent allocation to membrane ruffles, newly organized stress fibers, and discrete cytoplasmic actin-rich patches. These patches also contained alpha-actinin-1 and alpha-actinin-4, vinculin, paxillin, alpha-tubulin, and PI3-kinase. Cytochalasin D treatment resulted in RelA/p65 redistribution to actin-containing aggregates, with the number of cells with RelA/p65-containing clusters in the cytoplasm increasing under the effect of EGF. Furthermore, EGF proved to induce RelA/p65 accumulation in the nucleus after cell pretreatment with actin-stabilizing and actin-destabilizing agents, which was accompanied by changes in its DNA-binding activity after either EGF stimulation or cytochalasin D treatment. Thus, EGF treatment of A431 cells results in simultaneous nuclear RelA/p65 translocation and cytoplasmic redistribution, with part of RelA/p65 pool forming a very tight association with actin-rich structures. Apparently, nuclear transport is independent on drug stabilization or destabilization of the actin.

  • 18.
    Bolshakova, A.V.
    et al.
    Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
    Petukhova, O.A.
    Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
    Pinaev, G.P.
    Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russia.
    Magnusson, Karl-Erik
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Comparative analysis of subcellular fractionation methods for revealing a-actinin 1 and a-actinin 4 in A431 cells2009In: Cell and Tissue Biology, ISSN 1990-519X, Vol. 3, no 2, 188-197 p.Article in journal (Refereed)
    Abstract [en]

    a-Actinin 1 and a-actinin 4 are actin-binding proteins with shared structural functions that are responsible for the regulation of several processes in the cell. Based on previous data on the different distribution of these proteins in the nucleus and cytoplasm, we have studied in detail the presence of a-actinin 1 and a-actinin 4 in subcellular fractions in the A431 cells spread on fibronectin. The detection of a-actinins in some particular fractions has been shown to depend on the method of lysis, as well as whether the preliminary low-temperature freezing of cells was used. The application of various fractionation methods has allowed us to conclude that a-actinin 4 is present in all cytoplasmic and nuclear subfractions, whereas, in addition to in the cytoplasm, a-actinin 1 can also be revealed in the nuclear envelope fraction.

  • 19.
    Bolshakova, A.V.
    et al.
    Institute of Cytology RAS, St. Petersburg, Russian Federation.
    Petukhova, O.A.
    Institute of Cytology RAS, St. Petersburg, Russian Federation.
    Pinaev, G.P.
    Institute of Cytology RAS, St. Petersburg, Russian Federation.
    Magnusson, Karl-Erik
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    The comparative analysis of subcellular fractionation methods for revealing of a-actinin 1 and a-actinin 4 in A431 cells2009In: Tsitologiya, ISSN 0041-3771, Vol. 51, no 2, 122-129 p.Article in journal (Refereed)
    Abstract [en]

    a-Actinin 1 and a-actinin 4 belong to a family of actin-binding proteins with shared structural function and regulation of several processes in a cell. Based on previous data on different distribution of these proteins in the nucleus and cytoplasm, we have explored in detail the distribution of a-actinin 1 and a-actinin 4 in subcellular fractions in A431 cells spread on fibronectin. Several methods of subcellular fractionation were used. Complex approach allowed resuming that revealing of a-actinin isoforms in fractions depended on the composition of lysis buffer and preliminary low-temperature freezing of the cells. We have drawn a conclusion that a-actinin 4 can be found in all cytoplasmic and nuclear subfractions, while a-actinin 1 is characterized by cytoplasmic and membrane localization with specificity of its distribution tightly to the nuclear membrane.

  • 20.
    Borutinskaite, Veronica
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Navakauskiene, Ruta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Effects of retinoic acid and histone deacetylase inhibitor Bml-210 on protein expression in NB4 cells2005In: Biologija, ISSN 1392-0146, Vol. 4, 88-93 p.Article in journal (Refereed)
  • 21.
    Borutinskaite, Veronica
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Navakauskiene, Ruta
    Department of Developmental Biology, Institute of Biochemistry, Vilnius, Lithuania .
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Retinoic acid and histone deacelytase inhibitor BML-210 inhibit proliferation of human cervical cancer HeLa cells2006In: Annals of the New York Academy of Sciences, ISSN 0077-8923, Vol. 1091, 346-355 p.Article in journal (Refereed)
    Abstract [en]

    Human papillomavirus (HPV) infection is believed to be the central cause of cervical cancer. The viral proteins E6 and E7 from high-risk HPV types prevent cells from differentiating apoptosis and inducing hyperproliferative lesions. Human cervical carcinoma HeLa cells contain integrated human papillomavirus type 18 (HPV-18). Retinoic acid (RA) is a key regulator of epithelial cell differentiation and a growth inhibitor in vitro of HeLa cervical carcinoma cells. Cellular responses to RA are mediated by nuclear retinoic acid receptors (RARs) and retinoid X receptors. On the other hand, histone deacetylase inhibitors have been shown to be chemopreventive agents for the treatment of cancer cells. In this article, we have examined the antiproliferative effect of RA and histone deacetylase inhibitor BML-210 on HeLa cells, and particularly the effects on protein expression that may be involved in the cell cycle control and apoptosis. Our data suggest that a combination of RA and BML-210 leads to cell growth inhibition with subsequent apoptosis in a treatment time-dependent manner. We confirm that BML-210 alone or in combination with RA causes a marked increase in the level of p21. The changes in the p53 level are under the influence of p38 phosphorylation. We also discovered that the histone deacetylase inhibitor BML-210 causes increased levels of anti-apoptotic protein Bcl-2 and phosphorylated p38 MAP Kinase; the latter link in cell cycle arrest with response to extracellular stimuli. Our results suggest that RA and BML-210 are involved in different signaling pathways that regulate cell cycle arrest and lead to apoptosis of HeLa cells.

  • 22.
    Borutinskaite, Veronika V
    et al.
    Vilnius State University, Lithuania .
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Navakauskiene, Ruta
    Vilnius State University, Lithuania .
    Histone deacetylase inhibitor BML-210 induces growth inhibition and apoptosis and regulates HDAC and DAPC complex expression levels in cervical cancer cells2012In: Molecular Biology Reports, ISSN 0301-4851, E-ISSN 1573-4978, Vol. 39, no 12, 10179-10186 p.Article in journal (Refereed)
    Abstract [en]

    Histone deacetylase inhibitors (HDACIs) represent a new class of targeted anti-cancer agents and different other diseases, like muscular disorders. A number of studies have shown that extracellular signal-activated kinases can target chromatin-modifying complexes directly and regulate their function. The molecular connection between the dystrophin-associated protein complex (DAPC) and chromatin has been described, by showing that NO signaling regulates histone deacetylase (HDAC) activity and influences gene expression in different cell types. In present study, we investigated HDACs changes in HeLa cells undergoing growth inhibition and apoptosis, caused by HDACI BML-210 and retinoic acid (ATRA). Cell cycle analysis indicated that HeLa cell treatment with 20 and 30 mu M concentration of BML-210 increased the proportion of cells in G0/G1 phase, and caused accumulation in subG1, indicating that the cells are undergoing apoptosis. We determined down-regulation of HDAC 1-5 and 7 after treatment with BML-210. Also, we demonstrated expression of different isoforms of alpha-dystrobrevin (alpha-DB) and other components of DAPC such as syntrophin, dystrophin, beta-dystrobrevin (beta-DB) and NOS in HeLa cells after treatments. We determined changes in protein expression level of dystrophin, NOS1, alpha- and beta-DB and in subcellular localization of alpha-DB after treatments with BML-210 and ATRA. In conclusion, these results suggest that HDACI BML-210 can inhibit cell growth and induce apoptosis in cervical cancer cells, what correlates with down-regulation of HDAC class I and II and changes in the DAPC expression levels. This can be important for identifying target proteins in DAPC signaling to HDACs, as a target of pharmacological intervention for treatment of muscular dystrophies and other diseases.

  • 23.
    Borutinskaité, Veronika
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Navakauskiene, R
    Institute for Biochemistry, Vilnius.
    alpha-Dystrobrevin distribution and association with other proteins in human promyelocytic NB4 cells treated for granulocytic differentiation2011In: MOLECULAR BIOLOGY REPORTS, ISSN 0301-4851, Vol. 38, no 5, 3001-3011 p.Article in journal (Refereed)
    Abstract [en]

    Dystrobrevins (DBs) bind directly to dystrophin and are prominent components of the dystrophin-associated protein complex (DAPC) that links the cytoskeleton to the extracellular matrix. They are involved in brain development, synapse formation and plasticity, as well as water and ion homeostasis. However, the role of DB in non-muscular cells is not clear. In this study, we show that different alpha-dystrobrevin isoforms are present in promyelocytic leukemia (NB4) cells. Only the biggest alpha-dystrobrevin isoform (DB-alpha), which can be important for its function, was expressed in the membrane fraction of NB4 cells; the other alpha-DB isoforms were found in the hydrophilic cell fractions. Employing the immunoprecipitation and mass spectrometry, we identified novel alpha-DB-interacting proteins involved in cytoskeleton reorganization (actin, tropomyosin, gelsolin, tubulin) and signal transduction process (stathmin, prohibitin, RIBA) during proliferation and differentiation of NB4 cells. Our results suggest that alpha-DB isoforms play a central role in cytoskeleton reorganization via their multiple interactions with actin and actin-associating proteins and may participate in signal transduction process during NB4 cell granulocytic differentiation via directly and non directly associated proteins.

  • 24. Connolly-Andersen, AM
    et al.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Mirazimi, A
    Basolateral entry and release of Crimean-Congo hemorrhagic fever virus in polarized MDCK-1 cells2007In: Journal of Virology, ISSN 0022-538X, Vol. 81, no 5, 2158-2164 p.Article in journal (Refereed)
    Abstract [en]

    Crimean-Congo hemorrhagic fever virus (CCHFV) is an etiological agent of a disease with mortality rates in patients averaging 30%. The disease is characterized by fever, myalgia, and hemorrhage. Mechanisms underlying the hemorrhage have to our knowledge not been elucidated for CCHFV. Possibly, a direct or indirect viral effect on tight junctions (TJ) could cause the hemorrhage observed in patients, as TJ play a crucial role in vascular homeostasis and can cause leakage upon deregulation. Moreover, there is no knowledge regarding the site of entry and release of CCHFV in polarized epithelial cells. Such cells represent a barrier to virus dissemination within the host, and as a site of viral entry and release, they could play a key role in further spread. For the first time, we have shown preferential basolateral entry of CCHFV in Madin-Darby canine kidney 1 (MDCK-1) epithelial cells. Furthermore, we demonstrated basolateral release of CCHFV in polarized epithelial cells. Interestingly, by measuring transepithelial electrical resistance, we found no effect of CCHFV replication on the function of TJ in this study. Neither did we observe any difference in the localization of the TJ proteins ZO-1 and occludin in CCHFV-infected cells compared to mock-infected cells. Copyright © 2007, American Society for Microbiology. All Rights Reserved.

  • 25. Grdic, D
    et al.
    Ekman, L
    Schon, K
    Lindgren, K
    Mattsson, J
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Ricciardi-Castagnoli, P
    Lycke, N
    Splenic marginal zone dendritic cells mediate the cholera toxin adjuvant effect: Dependence on the ADP-ribosyltransferase activity of the holotoxin2005In: Journal of Immunology, ISSN 0022-1767, Vol. 175, no 8, 5192-5202 p.Article in journal (Refereed)
    Abstract [en]

    The in vivo mechanisms of action of most vaccine adjuvants are poorly understood. In this study, we present data in mice that reveal a series of critical interactions between the cholera toxin (CT) adjuvant and the dendritic cells (DC) of the splenic marginal zone (MZ) that lead to effective priming of an immune response. For the first time, we have followed adjuvant targeting of MZ DC in vivo. We used CT-conjugated OVA and found that the Ag selectively accumulated in MZ DC following i.v. injections. The uptake of Ag into DC was GM1 ganglioside receptor dependent and mediated by the B subunit of CT (CTB). The targeted MZ DC were quite unique in their phenotype: CD11c(+), CD8 alpha(-), CD11b(-), B220(-), and expressing intermediate or low levels of MHC class II and DEC205. Whereas CTB only delivered the Ag to MZ DC, the ADP-ribosyltransferase activity of CT was required for the maturation and migration of DC to the T cell zone, where these cells distinctly up-regulated CD86, but not CD80. This interaction appeared to instruct Ag-specific CD4(+) T cells to move into the B cell follicle and strongly support germinal center formations. These events may explain why CT-conjugated Ag is substantially more immunogenic than Ag admixed with soluble CT and why CTB-conjugated Ag can tolerize immune responses when given orally or at other mucosal sites.

  • 26.
    Gustafsson, Mikael
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    A distributed image-processing system for measurements of intracellular calcium in living cells1991In: Computer Methods and Programs in Biomedicine, ISSN 0169-2607, E-ISSN 1872-7565, Vol. 36, no 4, 199-221 p.Article in journal (Refereed)
    Abstract [en]

    During the last decade, image-processing techniques have been introduced as a valuable tool in biologically oriented research. In combination with novel fluorescent probes, these techniques permit assessment of subcellular distributions of several intracellularly important cations, such as free calcium ions and protons. Typically, systems used for image processing are located centrally around the experimental setup. This configuration has drawbacks, mainly because the laborious extraction and processing of data that generally follow an experimental session limits the access to the system for other investigators. We describe here the principles of a distributed image processing system, based on IBM-compatible personal computers (PCs), that without extra hardware can cope with all the necessary image processing involved in imaging of intracellular cations. The potential of the PC as an image processor, however, reaches beyond this specific application and many image processing tasks can be carried out successfully on a standard PC. Thus, the centrally located dedicated image processor is used only for image acquisition in the experimental situation. This in turn optimizes the utilization of expensive resources and increases efficiency. The mouse-operated software is described in detail, so that interested investigators can extract useful parts for integration into their own applications and experimental environment.

  • 27.
    Gustafsson, Mikael
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    A novel principle for quantitation of fast intracellular calcium changes using Fura-2 and a modified image processing system: applications in studies of neutrophil motility and phagocytosis1992In: Cell Calcium, ISSN 0143-4160, E-ISSN 1532-1991, Vol. 13, no 8, 473-486 p.Article in journal (Refereed)
    Abstract [en]

    A new principle is described for imaging intracellular free calcium [Ca2+]i changes in single, living cells utilizing the fluorescent probe Fura-2. It is based upon video color mixing in real time and allows high-speed visualization, at maximum image resolution, of [Ca2+]i changes without digital image ratioing. The epifluorescence images produced by 340 and 380 nm excitations are stored in two memory buffers of a personal computer-based image processing system. Two video signals are generated independently from each buffer and connected to the red and green inputs of a video display. An image is this way created, in which [Ca2+]i shows up as a specific hue, whereas changes in dye concentration, light intensity, cell thickness show up as variations in brightness of the imaged cells. The method has advantages over conventional ratio imaging, notably simplicity and speed, since no calculations are made. Yet it can be combined with traditional digital image processing. The imaging technique allows monitoring of [Ca2+]i changes in rapidly moving cells, like neutrophils. It is demonstrated that during random locomotion on serum-coated glass surfaces, [Ca2+]i levels appeared to oscillate and that the frequency of the oscillations are related to locomotive activity. Furthermore, in Ca2+ free medium, the cells continue to move and phagocytose in the presence of Ca2+ ionophore (ionomycin) and 2 mM EGTA. In the presence of 1 mM extracellular Ca2+, ionomycin-treated cells were not able to move or phagocytose.

  • 28.
    Gustafsson, Mikael
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lateral diffusion of the secretory component (SC) in the basolateral membrane of the human colon carcinoma cell line HT29 assessed with fluorescence recovery after photobleaching1988In: Journal of Cellular Physiology, ISSN 0021-9541, E-ISSN 1097-4652, Vol. 137, no 3, 608-611 p.Article in journal (Refereed)
    Abstract [en]

    The lateral diffusion of the secretory component (SC), acting as a receptor for dimeric IgA in the basolateral side of intestinal epithelial cells, was studied in the human colonic carcinoma cell line HT29. The HT29 cells were grown in Dulbecco's modified Eagle's medium in which galactose had been substituted for glucose to promote development of small intestine-like cells, with a distinct separation of the basolateral side from the apical surface. The SC was stained with rhodamine-labeled polyclonal anti-human SC rabbit antibodies (Ig) or Fab fragments, and the lateral mobility was assessed with the fluorescence recovery after photobleaching technique. The average lateral diffusion was consistent with a diffusion constant of 7.7 ± 2.0 (mean value ± SD; n = 29) and 7.1 ± 2.3 (n = 30) × 10−10 cm2s−1 for Ig-and Fab-labeled receptors, respectively, which is slower than lipid diffusion but is similar to that found for other membrane receptors. The corresponding values for the fraction of mobile receptors were 66 ± 13% and 71 ± 12%, respectively. Cells were labeled from the top of the culture plate, and cells adjacent to a mechanically made rift or a natural opening in the cell monolayer were labeled more strongly, confirming the microscope-based impression that the basolateral surface primarily harboured the SC receptor.

  • 29.
    Gustavsson, Johanna
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Parpal, Santiago
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Margareta
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Ramsing, Cecilia
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Thorn, Hans
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Borg, Marie
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Lindroth, Margaretha
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Strålfors, Peter
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Localization of the insulin receptor in caveolae of adipocyte plasma membrane1999In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 13, no 14, 1961-1971 p.Article in journal (Refereed)
    Abstract [en]

    The insulin receptor is a transmembrane protein of the plasma membrane, where it recognizes extracellular insulin and transmits signals into the cellular signaling network. We report that insulin receptors are localized and signal in caveolae microdomains of adipocyte plasma membrane. Immunogold electron microscopy and immunofluorescence microscopy show that insulin receptors are restricted to caveolae and are colocalized with caveolin over the plasma membrane. Insulin receptor was enriched in a caveolae-enriched fraction of plasma membrane. By extraction with β-cyclodextrin or destruction with cholesterol oxidase, cholesterol reduction attenuated insulin receptor signaling to protein phosphorylation or glucose transport. Insulin signaling was regained by spontaneous recovery or by exogenous replenishment of cholesterol. β-Cyclodextrin treatment caused a nearly complete annihilation of caveolae invaginations as examined by electron microscopy. This suggests that the receptor is dependent on the caveolae environment for signaling. Insulin stimulation of cells prior to isolation of caveolae or insulin stimulation of the isolated caveolae fraction increased tyrosine phosphorylation of the insulin receptor in caveolae, demonstrating that insulin receptors in caveolae are functional. Our results indicate that insulin receptors are localized to caveolae in the plasma membrane of adipocytes, are signaling in caveolae, and are dependent on caveolae for signaling.

  • 30.
    Hagbom, Marie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Istrate, Claudia
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology.
    Engblom, David
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Thommie
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology.
    Rodriguez-Diaz, Jesus
    University of Valencia.
    Buesa, Javier
    University of Valencia.
    Taylor, John A
    University of Auckland.
    Loitto, Vesa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Ahlman, Hakan
    University of Gothenburg.
    Lundgren, Ove
    University of Gothenburg.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Rotavirus Stimulates Release of Serotonin (5-HT) from Human Enterochromaffin Cells and Activates Brain Structures Involved in Nausea and Vomiting2011In: PLOS PATHOGENS, ISSN 1553-7366, Vol. 7, no 7Article in journal (Refereed)
    Abstract [en]

    otavirus (RV) is the major cause of severe gastroenteritis in young children. A virus-encoded enterotoxin, NSP4 is proposed to play a major role in causing RV diarrhoea but how RV can induce emesis, a hallmark of the illness, remains unresolved. In this study we have addressed the hypothesis that RV-induced secretion of serotonin (5-hydroxytryptamine, 5-HT) by enterochromaffin (EC) cells plays a key role in the emetic reflex during RV infection resulting in activation of vagal afferent nerves connected to nucleus of the solitary tract (NTS) and area postrema in the brain stem, structures associated with nausea and vomiting. Our experiments revealed that RV can infect and replicate in human EC tumor cells ex vivo and in vitro and are localized to both EC cells and infected enterocytes in the close vicinity of EC cells in the jejunum of infected mice. Purified NSP4, but not purified virus particles, evoked release of 5-HT within 60 minutes and increased the intracellular Ca(2+) concentration in a human midgut carcinoid EC cell line (GOT1) and ex vivo in human primary carcinoid EC cells concomitant with the release of 5-HT. Furthermore, NSP4 stimulated a modest production of inositol 1,4,5-triphosphate (IP(3)), but not of cAMP. RV infection in mice induced Fos expression in the NTS, as seen in animals which vomit after administration of chemotherapeutic drugs. The demonstration that RV can stimulate EC cells leads us to propose that RV disease includes participation of 5-HT, EC cells, the enteric nervous system and activation of vagal afferent nerves to brain structures associated with nausea and vomiting. This hypothesis is supported by treating vomiting in children with acute gastroenteritis with 5-HT(3) receptor antagonists.

  • 31.
    Hollén, Elisabet
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Högberg, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Laurin, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Urinary nitric oxide during one year of gluten-free diet with or without oats in children with coeliac disease2006In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 41, no 11, 1272-1278 p.Article in journal (Refereed)
    Abstract [en]

    Objective. Although in both adults and children with coeliac disease (CD) it is now recommended that oats be added to their gluten-free diet, there is still some controversy concerning the possible harmful effects of oats in some individuals. In this study concentrations of nitric oxide metabolites were repeatedly measured in the urine of children under investigation for CD, when on a gluten-free diet with or without oats.

    Material and methods. The study included 116 children, randomized to a standard gluten-free diet (GFD-std) or a gluten-free diet supplemented with wheat-free oat products (GFD-oats), over a one-year period. Small-bowel biopsy was performed at the beginning and end of the study. Morning urine samples were collected from 87 children and urinary nitrite/nitrate concentrations were monitored at 0, 3, 6, 9 and 12 months.

    Results. All patients were in clinical remission after the study period. There was a rapid decline in urinary nitrite/nitrate concentrations in both groups as early as after 3 months. No differences were seen between the study groups at any of the checkpoints. However, at the end of the study, the nitrite/nitrate values of 9 children in the GFD-oats group and 8 children in the GFD-std group had not normalized.

    Conclusions. Children with CD on a gluten-free diet with oats display a similar reduction in urinary nitrite/nitrate as those on a traditional gluten-free diet. Some children, however, still demonstrate high nitrite/nitrate excretion after one year on either diet, indicating that long-term follow-up studies of children on an oats-containing diet are needed.

  • 32.
    Hollén, Elisabet
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Grodzinsky, Ewa
    Högberg, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Laurin, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Coeliac children on a gluten-free diet with or without oats display equal anti-avenin antibody titres2006In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 41, no 1, 42-47 p.Article in journal (Refereed)
    Abstract [en]

    Objective. Recent studies report negligible toxicity of oats in the majority of coeliac disease (CD) patients. It has previously been shown that children with untreated CD have circulating antibodies to oats avenin. In this study we performed serial assessments of anti-avenin antibodies in children under investigation for CD on a gluten-free diet with or without oats.

    Material and methods. The study involved 116 children, randomized to a standard gluten-free diet or a gluten-free diet supplemented with oats. Sera were obtained from 86 children, 48 in the standard gluten-free group and 38 in the gluten-free oats group, of which 33 consumed at least 10 g of oats daily. IgA and IgG anti-avenin antibodies were monitored at 0, 3, 6 and 12 months. Nitric oxide metabolites were measured in 7 patients, with deviating antibody results.

    Results. There was a significant decrease in anti-avenin antibodies in both groups at the end as compared to the beginning of the study, (p<0.001), but no difference was found between the two groups. IgA titres already declined after 3 months. IgG titres, although significantly decreased, remained high in the majority of patients in both groups. Nitric oxide levels were high in four of the analysed samples.

    Conclusions. Oats per se, do not seem to produce a humoral immune reaction in children with CD when given in an otherwise gluten-free diet, indicating that the reaction requires gluten challenge. Anti-avenin antibodies were equal in the two study groups, and these findings strengthen the clinical impression that oats can be tolerated by the majority of patients with CD.

  • 33.
    Hollén, Elisabet
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Högberg, Lotta
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Stenhammar, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Antibodies to oat prolamines (avenins) in children with coeliac disease2003In: Scandinavian Journal of Gastroenterology, ISSN 0036-5521, Vol. 38, no 7, 742-746 p.Article in journal (Refereed)
    Abstract [en]

    Background: The use of oats in a gluten-free diet for children with coeliac disease is presently under investigation. In this study we measured the content of antibodies to oat prolamines (avenin) in sera from coeliac children and reference children.

    Methods: Crude avenin was prepared by extraction with ethanol and salt-solution and used as antigen in a three-step ELISA. Sera from 81 children, including 34 children with verified coeliac disease, were analysed for both IgA and IgG antibodies to avenin and gliadin. Sera were also incubated with gliadin before exposure to avenin, and vice versa, to assess a possible cross-reaction between the species. Keyhole limpet hemocyanin (KLH) was used as a negative control.

    Results: Children with coeliac disease on a normal diet had significantly higher levels of antibodies to avenin, both IgG and IgA, than reference children ( P < 0.001) and the levels correlated positively with gliadin antibodies, especially of IgA-type ( r = 0.798). Both anti-avenin and anti-gliadin antibodies were only absorbed by the corresponding protein.

    Conclusions: Children with coeliac disease have antibodies to oat proteins at significantly higher levels than reference children. The absorption test did not indicate a cross-reactivity between the prolamines of wheat and oats. The method will be employed for repeated sampling of anti-avenin antibodies during a prospective interventional study with a gluten-free diet supplemented with oats.

  • 34.
    Holm, Angelika
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Vikström, Elena
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Pseudomonas aeruginosa N-3-oxo-dodecanoyl-homoserine Lactone Elicits Changes in Cell Volume, Morphology, and AQP9 Characteristics in Macrophages2016In: Frontiers in Cellular and Infection Microbiology, E-ISSN 2235-2988, Vol. 6, no 32Article in journal (Refereed)
    Abstract [en]

    Quorum sensing (QS) communication allows Pseudomonas aeruginosa to collectively control its population density and the production of biofilms and virulence factors. QS signal molecules, like N-3-oxo-dodecanoyl-L-homoserine lactone (30-C-12-HSL), can also affect the behavior of host cells, e.g., by modulating the chemotaxis, migration, and phagocytosis of human leukocytes. Moreover, host water homeostasis and water channels aquaporins (AQP) are critical for cell morphology and functions as AQP interact indirectly with the cell cytoskeleton and signaling cascades. Here, we investigated how P aeruginosa 30-C-12-HSL affects cell morphology, area, volume and AQP9 expression and distribution in human primary macrophages, using quantitative PCR, immunoblotting, two- and three-dimensional live imaging, confocal and nanoscale imaging. Thus, 30-C-12-HSL enhanced cell volume and area and induced cell shape and protrusion fluctuations in macrophages, processes tentatively driven by fluxes of water across cell membrane through AQP9, the predominant AQP in macrophages. Moreover, 30-C-12-HSL upregulated the expression of AQP9 at both the protein and mRNA levels. This was accompanied with enhanced whole cell AQP9 fluorescent intensity and redistribution of AQP9 to the leading and trailing regions, in parallel with increased cell area in the macrophages. Finally, nanoscopy imaging provided details on AQP9 dynamics and architecture within the lamellipodial area of 30-C-12-HSL-stimulated cells. We suggest that these novel events in the interaction between P aeruginosa and macrophage may have an impact on the effectiveness of innate immune cells to fight bacteria, and thereby resolve the early stages of infections and inflammations.

  • 35.
    Holm, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Mechanical manipulation of polymorphonuclear leukocyte plasma membranes with optical tweezers causes influx of extracellular calcium through membrane channels1999In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 37, no 3, 410-412 p.Article in journal (Refereed)
    Abstract [en]

    Optical tweezers are used mechanically to manipulate the plasma membrane of polymophonuclear leukocytes attached to the bottom of a glass manipulation chamber. The laser trapping beam is dragged across the membrane of cells in calcium-containing and calcium-depleted extracellular medium. This treatment causes a significant rise in the intracellular calcium concentration compared with controls, in cells in calcium-containing medium (239.8±49.0% against 75.4±16.4%, respectively), but not in cells in calcium-depeleted medium (69.1±9.6% against 83.4±18.5%, respectively), indicating that the calcium rise is caused by an influx of calcium from the environment. The rise in calcium concentration is blocked (23.5±7.1% against 17.1±4.1%, respectively) by the addition of lansoprazole, indicating that the influx is not due to unspecific membrane damage caused by the mechanical manipulation of the cell. It can therefore be concluded that mechanical manipulation of the neutrophil membrane, in the piconewton force range exerted by the optical tweezer, does not damage the plasma membrane but stimulates a mechanically inducible, membrane channel-mediated influx of extracellular calcium.

  • 36.
    Holm, Åsa
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tejle, Katarina
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, T.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS - Institut Armand-Frappier, Université du Québec.
    Rasmusson, Birgitta
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Protein C α regulates phagocytosis actin dynamics and phagosomal maturation in macrophagesManuscript (preprint) (Other academic)
    Abstract [en]

    Protein kinase C α (PKCα) participates in F-actin remodeling during phagocytosis and phagosomal maturation in macrophages. Promastigotes of the protozoan parasite Leishmania donovani cause an accumulation of periphagosomal F-actin instead of the normal decrease seen with other prey [1]. This accumulation is dependent on promastigote lipophosphoglycan (LPG), which has several detrimental effects on the cell including inhibition of PKCα activity.

    To directly address the role of PKCα and LPG for actin remodeling in macrophages, we investigated F-actin dynamics in RAW 264.7 macrophages overexpressing a dominant-negative mutant of PKCα (DN PKCα). We found that DN PKCα-overexpressing cells displayed increased levels of cortical F-actin and decreased phagocytic capacity, which was augmented when the cells were subjected to LPG-coated prey. The DN PKCα-overexpressing cells also showed defective breakdown of periphagosomal F-actin and inhibition of phagosomal maturation. The level of periphagosomal F-actin was similar to that of controls subjected to LPG-coated prey. Our results show that PKCα regulates phagocytosis and F-actin turnover in macrophages, and that PKCα-dependent breakdown of periphagosomal F-actin is required for normal phagosomal maturation.

  • 37.
    Holm, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tejle, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Gunnarsson, T.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS—Institut Armand-Frappier, Université du Québec, Laval, Qué., Canada.
    Rasmusson, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Role of protein kinase C α for uptake of unopsonized prey and phagosomal maturation in macrophages2003In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 302, no 4, 653-658 p.Article in journal (Refereed)
    Abstract [en]

    Protein kinase C α (PKCα) participates in F-actin remodeling during phagocytosis and phagosomal maturation in macrophages. Leishmania donovani promastigotes, which inhibit phagosomal maturation, cause accumulation of periphagosomal F-actin instead of the dissassembly observed around other prey [Cell. Microbiol. 7 (2001) 439]. This accumulation is induced by promastigote lipophosphoglycan (LPG), which has several effects on macrophages including inhibition of PKCα. To investigate a possible connection between PKCα and LPG’s effects on actin dynamics, we utilized RAW264.7 macrophages overexpressing dominant-negative PKCα (DN PKCα). We found increased cortical F-actin and decreased phagocytic capacity, as well as defective periphagosomal F-actin breakdown and inhibited phagosomal maturation in the DN PKCα-overexpressing cells, effects similar to those seen in controls subjected to LPG-coated prey. The results indicate that PKCα is involved in F-actin turnover in macrophages and that PKCα-dependent breakdown of periphagosomal F-actin is required for phagosomal maturation, and endorse the hypothesis that intracellular survival of L. donovani involves inhibition of PKCα by LPG.

  • 38.
    Holm, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tejle, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, Canada.
    Rasmusson, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Leishmania donovani lipophosphoglycan causes periphagosomal actin accumulation: correlation with impaired translocation of PKCα and defective phagosome maturation2001In: Cellular Microbiology, ISSN 1462-5814, E-ISSN 1462-5822, Vol. 3, no 7, 439-447 p.Article in journal (Refereed)
    Abstract [en]

    Lipophosphoglycan (LPG) is the major surface glycoconjugate of Leishmania donovani promastigotes. The repeating disaccharide–phosphate units of LPG are crucial for promastigote survival inside macrophages and establishment of infection. LPG has a number of effects on the host cell, including inhibition of PKC activity, inhibition of nitric oxide production and altered expression of cytokines. LPG also inhibits phagosomal maturation, a process requiring depolymerization of periphagosomal F-actin. In the present study, we have characterized the dynamics of F-actin during the phagocytosis of L. donovani promastigotes in J774 macrophages. We observed that F-actin accumulated progressively around phagosomes containing wild-type L. donovani promastigotes during the first hour of phagocytosis. Using LPG-defective mutants and yeast particles coated with purified LPG, we obtained evidence that this effect could be attributed to the repeating units of LPG. LPG also disturbed cortical actin turnover during phagocytosis. The LPG-dependent accumulation of periphagosomal F-actin correlated with an impaired recruitment of the lysosomal marker LAMP1 and PKCα to the phagosome. Accumulation of periphagosomal F-actin during phagocytosis of L. donovani promastigotes may contribute to the inhibition of phagosomal maturation by physically preventing vesicular trafficking to and from the phagosome.

  • 39.
    Holm, Åsa
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Winberg, M. E.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Särndahl, E.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Descoteaux, A.
    INRS- lnstitut Annand-Frappier, Université du Quebec, Laval, Québéc, Canada.
    Rasmusson, Birgitta
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lipid rafts are required for the effects of Leishmania donovani lipophosphoglycan on periphagosomal F-actin and phagosomal maturationManuscript (preprint) (Other academic)
    Abstract [en]

    Lipophosphoglycan (LPG) is the major surface glycoconjugate on Leishmania donovani promastigotes, and is cmcial for pro mastigote survival following phagocytosis by macrophages. LPG consists of a chain of repeating phosphodisaccharides anchored to the parasite membrane by a lysophosphatidylinositol lipid anchor with an unusually long saturated fatty acid residue. During phagocytosis, LPG transfers from the parasite surface to the plasma membrane of the host macrophage. The presence of LPG alters the biophysical properties of the host cell membrane and the signaling capacity of the macrophage. LPG induces accumulation ofF-actin around the phagosome, and inhibits phagosome maturation. The effects of LPG on the host ce!l include inhibition of PKCα, a PKC isoenzyme involved in F-actin tumover.

    The biophysical properties of the LPG lipid anchor suggest that it partitions into caveolae or lipid rafts, which are cholesterol-rich plasma membrane microdomains central for signal transduction. Since PKCa is enriched in caveolae/lipid rafts in other cell types, we investigated if lipid rafts constitute a platform for the interaction of LPG and PKCα. We found that the plasma membrane of human monocyte-derived macrophages were rich in lipid rafts, but did not contain caveolae. LPG colocalized with lipid raft markers after interaction with WT L. donovani promastigotes. The presence of LPG inhibited the translocation of PKCα to the plasma membrane. Destruction of lipid rafts by cholesterol depletion lead to a complete eradication of LPG's effects on periphagosomal F-actin and phagosomal maturation. We also found that cholesterol depletion reduced uptake of WT L. donovani promastigotes, while uptake of an LPG-defective mutant was not affected.

    We conclude that LPG partitions to lipid rafts in the plasma membrane of human macrophages and inhibits the translocation of PKCα to the membrane. The presence of lipid rafts is a prerequisite for LPG to exert its effects on host cell actin and phagosomal maturation.

  • 40.
    Holmström, Anna
    et al.
    Department of Microbiology, National Defence Research Establishment, Umeå, Sweden and the Department of Cell and Molecular Biology, Umeå University, Umeå, Sweden.
    Pettersson, Jonas
    Department of Cell and Molecular Biology, Umeå University, Umeå, Sweden.
    Rosqvist, Roland
    Department of Cell and Molecular Biology, Umeå University, Umeå, Sweden.
    Håkansson, Sebastian
    Department of Cell and Molecular Biology, Umeå University, Umeå, Sweden.
    Tafazoli, Farideh
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Fällman, Maria
    Department of Cell and Molecular Biology, Umeå University, Umeå, Sweden.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Wolf-Wats, Hans
    Department of Cell and Molecular Biology, Umeå University, Umeå, Sweden.
    Forsberg, Åke
    Department of Microbiology, National Defence Research Establishment, Umeå, Sweden.
    YopK of Yersinia pseudotuberculosis controls translocation of Yop effectors across the eukaryotic cell membrane1997In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 24, no 1, 73-91 p.Article in journal (Refereed)
    Abstract [en]

    Introduction of anti-host factors into eukaryotic cells by extracellular bacteria is a strategy evolved by several Gram-negative pathogens. In these pathogens, the transport of virulence proteins across the bacterial membranes is governed by closely related type III secretion systems. For pathogenic Yersinia, the protein transport across the eukaryotic cell membrane occurs by a polarized mechanism requiring two secreted proteins, YopB and YopD. YopB was recently shown to induce the formation of a pore in the eukaryotic cell membrane, and through this pore, translocation of Yop effectors is believed to occur (Håkansson et al., 1996b). We have previously shown that YopK of Yersinia pseudotuberculosis is required for the development of a systemic infection in mice. Here, we have analysed the role of YopK in the virulence process in more detail. A yopK-mutant strain was found to induce a more rapid YopE-mediated cytotoxic response in HeLa cells as well as in MDCK-1 cells compared to the wild-type strain. We found that this was the result of a cell-contact-dependent increase in translocation of YopE into HeLa cells. In contrast, overexpression of YopK resulted in impaired translocation. In addition, we found that YopK also influenced the YopB-dependent lytic effect on sheep erythrocytes as well as on HeLa cells. A yopK-mutant strain showed a higher lytic activity and the induced pore was larger compared to the corresponding wild-type strain, whereas a strain overexpressing YopK reduced the lytic activity and the apparent pore size was smaller. The secreted YopK protein was found not to be translocated but, similar to YopB, localized to cell-associated bacteria during infection of HeLa cells. Based on these results, we propose a model where YopK controls the translocation of Yop effectors into eukaryotic cells.

  • 41.
    Höddelius, Pia
    et al.
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Lirvall, Margareta
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Wasteson, Åke
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Loitto, Vesa
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Both Intra- and Extracellular Ca2 Participate in the Regulation of the Lateral Diffusion of the PDGF-β2 Receptor2000In: Bioscience Reports, ISSN 0144-8463, E-ISSN 1573-4935, Vol. 20, no 2, 119-127 p.Article in journal (Refereed)
    Abstract [en]

    When the receptors for platelet-derived growth factor (PDGF) are activatedthey aggregate, become tyrosine-phosphorylated and elicit a cascade ofdown-stream signals, including mobilization of Ca2+ from intra- andextracellular stores. Receptor mobility in the plane of the membrane isa prerequisite for receptor aggregation and further signalling. Using humanforeskin fibroblasts (AG 1523) and fluorescence recovery afterphotobleaching (FRAP), we therefore assessed the lateral mobilitycharacteristics of PDGF-β2 receptors by their diffusioncoefficient (D), and fraction of mobile receptors (R). This was done oncells stimulated with either normal human serum (NHS) or PDGF underdifferent Ca2+-conditions.

    The results suggest that both intra- and extracellular free Ca2+influence the mobility characteristics of the PDGF-β2receptor. Interestingly, the extracellular Ca2+ seems to imposegeneral restrictions on the mobility of receptors, since R increased whenextracellular Ca2+ was quenched with EGTA, whereas intracellularclamping of Ca2+ transients with MABTAM (BAPT/AM) primarily affectedD. When both intra- and extracellular Ca2+ were quenced, D remainedlow and R high, further supporting the proposition that they achievedistinct effects. Inhibition of tyrosine phosphorylation with Erbstatin,partly inhibited the NHS effects and released PDGF-induced receptorimmobilization. Ratio imaging with Fura-2 displayed that both NHS and PDGFinduced changes in intracellular free [Ca2+]. In view of the presentdata it might have important effects on the state of the receptor in themembrane, for instance by regulating its lateral mobility, communicationwith other receptors and signalling functions in the membrane.

  • 42.
    Högberg, Lotta
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Norrköping.
    Webb, C
    Lund University.
    Fälth-Magnusson, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Pediatrics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Paediatrics in Linköping.
    Forslund, Tony
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Danielsson, L
    Norrtalje Hospital.
    Ivarsson, A
    Umea University.
    Sandstrom, O
    Umea University.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Children with screening-detected coeliac disease show increased levels of nitric oxide products in urine2011In: ACTA PAEDIATRICA, ISSN 0803-5253, Vol. 100, no 7, 1023-1027 p.Article in journal (Refereed)
    Abstract [en]

    Aim: Increased concentration of nitric oxide (NO) metabolites, nitrite and nitrate, in the urine is a strong indication of ongoing small intestinal inflammation, which is a hallmark of the enteropathy of coeliac disease (CD). It has previously been shown that children with symptomatic, untreated CD have increased levels of NO oxidation products in their urine. The aim of this study was to investigate whether screening-detected, asymptomatic coeliac children display the same urinary nitrite/nitrate pattern. Methods: In a multicenter screening study, serum samples were collected from 7208 12-year-old children without previously diagnosed CD. Sera were analysed for anti-human tissue transglutaminase (tTG) of isotype IgA. Small bowel biopsy was performed in antibody-positive children, yielding 153 new cases of CD. In the screening-detected individuals, the sum of nitrite and nitrate concentrations in the urine was analysed and used as an indicator of NO production. For comparison, 73 children with untreated, symptomatic CD were studied. Results: The nitrite/nitrate levels in children with screening-detected CD and those with untreated symptomatic CD did not differ significantly. Both groups had significantly increased urinary nitrite/nitrate concentrations compared to the children with normal small bowel biopsy (p andlt; 0.001). Conclusion: Children with screening-detected CD have increased production of NO just as children with untreated symptomatic CD. High NO metabolite levels in the urine may indicate a pathogenetic feature of CD and be a marker of major clinical importance.

  • 43. Immerstrand, C
    et al.
    Nilsson, H
    Lindroth, Margaretha
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Sundqvist, Tommy
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Peterson, KH
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Confocal and electron microscopy of melanosome aggregation in Xenopus laevis melanophores2002In: Molecular Biology of the Cell, ISSN 1059-1524, Vol. 13, 2664- p.Conference paper (Other academic)
  • 44.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Hedlund, Joel
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Image correlation spectroscopy for quantification of pigment aggregationManuscript (preprint) (Other academic)
    Abstract [en]

    In the skin of amphibia, fish, and other organisms, the distribution of the pigment granules within melanophores regulates skin colour. In this study we have applied Image Correlation Spectroscopy (ICS; Petersen et al. 1998; Petersen et al. 1993) to monitor the aggregation of pigment granules. Normally in ICS, images from confocallaser scanning rnicroscopy are used to calculate autocorrelation functions from which the density of fluorescent particles in the image, like membrane receptors, can be obtained. The present study differs from traditional ICS in that the images are obtained by light microscopy and then Gaussian filtered to give the particles the appropriate intensity profile required for ICS analysis. ICS appears to be more sensitive than particle counting and image mean intensity for quantification of the degree of pigment aggregation. This study demonstrates for the first time that ICS can be used to analyse the aggregation of non-fluorescent particles, such as pigment granules in Xenopus laevis melanophores.

  • 45.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Hedlund, Joel
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, The Institute of Technology.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren-Peterson, Kajsa
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Organelle transport in melanophores analyzed by white light image correlation spectroscopy2007In: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 225, no 3, 275-282 p.Article in journal (Refereed)
    Abstract [en]

    Intracellular transport of organelles, vesicles and proteins is crucial in all eukaryotic cells, and is accomplished by motor proteins that move along cytoskeletal filaments. A widely used model of intracellular transport is Xenopus laevis melanophores. These cells help the frog to change color by redistributing melanin-containing organelles in the cytoplasm. The high contrast of the pigment organelles permits changes in distribution to be observed by ordinary light microscopy; other intracellular transport systems often require fluorescence labeling. Here we have developed white light Image Correlation Spectroscopy (ICS) to monitor aggregation and dispersion of pigment. Hitherto in ICS, images of fluorescent particles from Confocal Laser Scanning Microscopy (CLSM) have been used to calculate autocorrelation functions from which the density can be obtained. In the present study we show that ICS can be modified to enable analysis of light-microscopy images; it can be used to monitor pigment aggregation and dispersion, and distinguish between different stimuli. This new approach makes ICS applicable not only to fluorescent but also to black-and-white images from light or electron microscopy, and is thus very versatile in different studies of movement of particles on the membrane or in the cytoplasm of cells without potentially harmful fluorescence labeling and activation.

  • 46.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren Peterson, Kajsa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Krogh, Magnus
    Micromuscle AB, Linköping.
    Skoglund, Mia
    Micromuscle AB, Linköping.
    Selbing, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Conjugated-polymer micro- and milliactuators for biological applications2002In: MRS bulletin, ISSN 0883-7694, Vol. 27, no 6, 461-464 p.Article in journal (Refereed)
    Abstract [en]

    The development of new conjugated-polymer tools for the study of the biological realm, and for use in a clinical setting, is reviewed in this article. Conjugated-polymer actuators, based on the changes of volume of the active conjugated polymer during redox transformation, can be used in electrolytes employed in cell-culture media and in biological fluids such as blood, plasma, and urine. Actuators ranging in size from 10 μm to 100 μm suitable for building structures to manipulate single cells are produced with photolithographic techniques. Larger actuators may be used for the manipulation of blood vessels and biological tissue.

  • 47.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Jager, Edwin W.H.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Peterson, K.H.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Altered impedance during pigment aggregation in Xenopus laevis melanophores2003In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 41, no 3, 357-364 p.Article in journal (Refereed)
    Abstract [en]

    Melanophores are dark-brown pigment cells located in the skin of amphibia, fish and many invertebrates. The skin colour of these organisms is regulated by the translocation of pigment organelles, and the pigment distribution can be altered by external stimuli. The ability to change colour in response to stimuli makes these cells of interest for biosensing applications. It was investigated whether pigment aggregation in Xenopus laevis melanophores can be detected by impedance measurements performed in transparent microvials. The results show that cell attachment, cell spreading and pigment aggregation all resulted in impedance changes, seen particularly at the highest frequency tested (10 kHz). The mechanisms behind the impedance changes were investigated by the addition of latrunculin or melatonin, both of which cause pigment aggregation. The latrunculin-induced aggregation was associated with cell area decrease and filamentous actin (F-actin) breakdown, processes that can influence the impedance. Lack of F-actin breakdown and an increase in cell area during melatonin-induced aggregation suggest that some other intracellular process also contributes to the impedance decrease seen for melatonin. It was shown that impedance measurements reflect not only cell attachment and cell spreading, but also intracellular events.

  • 48.
    Immerstrand, Charlotte
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nilsson, Harriet
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lindroth, Margaretha
    Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Holmgren-Peterson, Kajsa
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Height changes associated with pigment aggregation in Xenopus laevis melanophores2004In: Bioscience Reports, ISSN 0144-8463, E-ISSN 1573-4935, Vol. 24, no 3, 203-214 p.Article in journal (Refereed)
    Abstract [en]

    Melanophores are pigment cells found in the skin of lower vertebrates. The brownish-black pigment melanin is stored in organelles called melanosomes. In response to different stimuli, the cells can redistribute the melanosomes, and thereby change colour. During melanosome aggregation, a height increase has been observed in fish and frog melanophores across the cell centre. The mechanism by which the cell increases its height is unknown. Changes in cell shape can alter the electrical properties of the cell, and thereby be detected in impedance measurements. We have in earlier studies of Xenopus laevis melanophores shown that pigment aggregation can be revealed as impedance changes, and therefore we were interested in investigating the height changes associated with pigment aggregation further. Accordingly, we quantified the changes in cell height by performing vertical sectioning with confocal microscopy. In analogy with theories explaining the leading edge of migrating cells, we investigated the possibility that the elevation of plasma membrane is caused by local swelling due to influx of water through HgC12-sensitive aquaporins. We also measured the height of the microtubule structures to assess whether they are involved in the height increase. Our results show that pigment aggregation in X. laevis melanophores resulted in a significant height increase, which was substantially larger when aggregation was induced by latrunculin than with melatonin. Moreover, the elevation of the plasma membrane did not correlate with influx of water through aquaporins or formation of new microtubules, Rather, the accumulation of granules seemed to drive the change in cell height.

  • 49. Istrate, C
    et al.
    Douagi, I
    Charpilienne, A
    McInnerney, GM
    Hidmark, Å
    Johansen, K
    Larsson, Marie
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Molecular Virology.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Poncet, D
    Svensson, Lennart
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Molecular Virology.
    Hinkula, Jorma
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Molecular Virology.
    Bone marrow dendritic cells internalize live RF-81 bovine rotavirus and rotavirus-like particles (RF 2/6-GFP-VLP and RF 8*2/6/7-VLP) but are only activated by live bovine rotavirus2007In: Scandinavian Journal of Immunology, ISSN 0300-9475, Vol. 65, no 6, 494-502 p.Article in journal (Refereed)
    Abstract [en]

    Dendritic cells (DC) represent the link between innate and adaptive immunity. They are classified as antigen-presenting cells (APC) and can initiate and modulate the immune response. To investigate the interaction with DCs, live RF-81 bovine rotavirus strain (RFV) and rotavirus-like particles (rota-VLP), RF 2/6-GFP-VLP and rota RF 8*2/6/7-VLP, were added in vitro to murine bone marrow-derived DCs (bmDCs). Live RFV, RF 2/6-GFP-VLP and RF 8*2/6/7-VLP all bound to bmDC and were internalized but only live RFV stimulated phenotypic maturation of the bmDCs as shown by the upregulation of the co-stimulatory molecule CD86. Even though bmDCs internalized RF 2/6-GFP-VLP and RF 8*2/6/7-VLP as efficiently as live RFV, these rota-VLP were not able to activate the cells. Supernatants derived from bmDC cultures treated with live RFV, RF 2/6-GFP-VLP or RF 8*2/6/7-VLP were examined for TNF-α production. At 6, 18 and 24 h post-infection, TNF-α concentrations were significantly increased in cultures treated with live RFV and rota-VLP compared with untreated cultures. In conclusion, this study showed that live RF-81 bovine rotavirus strain was internalized and induced bmDCs activation, whereas both RF 2/6-GFP-VLP and RF 8*2/6/7-VLP were internalized by bmDCs without triggering their activation. © 2007 The Authors.

  • 50.
    Istrate, Claudia
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Hagbom, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Vikström, Elena
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Rotavirus Infection Increases Intestinal Motility but Not Permeability at the Onset of Diarrhea2014In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 88, no 6, 3161-3169 p.Article in journal (Refereed)
    Abstract [en]

    The disease mechanisms associated with onset and secondary effects of rotavirus (RV) diarrhea remain to be determined and may not be identical. In this study, we investigated whether onset of RV diarrhea is associated with increased intestinal permeability and/or motility. To study the transit time, fluorescent fluorescein isothiocyanate (FITC)-dextran was given to RV-infected adult and infant mice. Intestinal motility was also studied with an opioid receptor agonist (loperamide) and a muscarinic receptor antagonist (atropine). To investigate whether RV increases permeability at the onset of diarrhea, fluorescent 4- and 10-kDa dextran doses were given to infected and noninfected mice, and fluorescence intensity was measured subsequently in serum. RV increased transit time in infant mice. Increased motility was detected at 24 h postinfection (h p.i.) and persisted up to 72 h p.i in pups. Both loperamide and atropine decreased intestinal motility and attenuated diarrhea. Analysis of passage of fluorescent dextran from the intestine into serum indicated unaffected intestinal permeability at the onset of diarrhea (24 to 48 h p.i.). We show that RV-induced diarrhea is associated with increased intestinal motility via an activation of the myenteric nerve plexus, which in turn stimulates muscarinic receptors on intestinal smooth muscles.

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