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  • 1.
    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.

  • 2.
    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, p. 119-127Article 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.

  • 3.
    Ingelsson, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Söderberg, Daniel
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Strid, Tobias
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Söderberg, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Bergh, Ann-Charlotte
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Loitto, Vesa-Matti
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Lotfi, Kourosh
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Haematology.
    Segelmark, Mårten
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Nephrology.
    Spyrou, Giannis
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Rosén, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Lymphocytes eject interferogenic mitochondrial DNA webs in response to CpG and non-CpG oligodeoxynucleotides of class C2018In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 115, no 3, p. E478-E487Article in journal (Refereed)
    Abstract [en]

    Circulating mitochondrial DNA (mtDNA) is receiving increasing attention as a danger-associated molecular pattern in conditions such as autoimmunity, cancer, and trauma. We report here that human lymphocytes [B cells, T cells, natural killer (NK) cells], monocytes, and neutrophils derived from healthy blood donors, as well as B cells from chronic lymphocytic leukemia patients, rapidly eject mtDNA as web filament structures upon recognition of CpG and non-CpG oligodeoxynucleotides of class C. The release was quenched by ZnCl2, independent of cell death (apoptosis, necrosis, necroptosis, autophagy), and continued in the presence of TLR9 signaling inhibitors. B-cell mtDNA webs were distinct from neutrophil extracellular traps concerning structure, reactive oxygen species (ROS) dependence, and were devoid of antibacterial proteins. mtDNA webs acted as rapid (within minutes) messengers, priming antiviral type I IFN production. In summary, our findings point at a previously unrecognized role for lymphocytes in antimicrobial defense, utilizing mtDNA webs as signals in synergy with cytokines and natural antibodies, and cast light on the interplay between mitochondria and the immune system.

  • 4.
    Karlsson, Thommie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Bolshakova, Anastasia
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magalhães, Marco A.O
    Faculty of Dentistry, University of Toronto, Toronto, Canada.
    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.
    Fluxes of Water through Aquaporin 9 Weaken Membrane-Cytoskeleton Anchorage and Promote Formation of Membrane Protrusions2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 4, p. e59901-Article in journal (Refereed)
    Abstract [en]

    All modes of cell migration require rapid rearrangements of cell shape, allowing the cell to navigate within narrow spaces in an extracellular matrix. Thus, a highly flexible membrane and a dynamic cytoskeleton are crucial for rapid cell migration. Cytoskeleton dynamics and tension also play instrumental roles in the formation of different specialized cell membrane protrusions, viz. lamellipodia, filopodia and membrane blebs. The flux of water through membrane-anchored water channels, known as aquaporins (AQPs) has recently been implicated in the regulation of cell motility, and here we provide novel evidence for the role of AQP9 in the development of various forms of membrane protrusion. Using multiple imaging techniques and cellular models we show that: (i) AQP9 induced and accumulated in filopodia, (ii) AQP9-associated filopodial extensions preceded actin polymerization, which was in turn crucial for their stability and dynamics, and (iii) minute, local reductions in osmolarity immediately initiated small dynamic bleb-like protrusions, the size of which correlated with the reduction in osmotic pressure. Based on this, we present a model for AQP9-induced membrane protrusion, where the interplay of water fluxes through AQP9 and actin dynamics regulate the cellular protrusive and motile activity of cells.

  • 5.
    Karlsson, Thommie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Glogauer, Michael
    University of Toronto.
    Ellen, Richard P
    University of Toronto.
    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.
    Magalhaes, Marco A O
    University of Toronto.
    Aquaporin 9 phosphorylation mediates membrane localization and neutrophil polarization2011In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673, Vol. 90, no 5, p. 963-973Article in journal (Refereed)
    Abstract [en]

    Neutrophils are of prime importance in the host innate defense against invading microorganisms by using two primary mechanisms-locomotion toward and phagocytosis of the prey. Recent research points to pivotal roles for water channels known as AQPs in cell motility. Here, we focused on the role of AQP9 in chemoattractant-induced polarization and migration of primary mouse neutrophils and neutrophil-like HL60 cells. We found that AQP9 is phosphorylated downstream of fMLFR or PMA stimulation in primary human neutrophils. The dynamics of AQP9 were assessed using GFP-tagged AQP9 constructs and other fluorescent markers through various live-cell imaging techniques. Expression of WT or the phosphomimic S11D AQP9 changed cell volume regulation as a response to hyperosmotic changes and enhanced neutrophil polarization and chemotaxis. WT AQP9 and S11D AQP9 displayed a very dynamic distribution at the cell membrane, whereas the phosphorylation-deficient S11A AQP9 failed to localize to the plasma membrane. Furthermore, we found that Rac1 regulated the translocation of AQP9 to the plasma membrane. Our results show that AQP9 plays an active role in neutrophil volume regulation and migration. The display of AQP9 at the plasma membrane depends on AQP9 phosphorylation, which appeared to be regulated through a Rac1-dependent pathway.

  • 6.
    Karlsson, Thommie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lagerholm, Christoffer B.
    University of So Denmark, Denmark .
    Vikström, Elena
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    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.
    Water fluxes through aquaporin-9 prime epithelial cells for rapid wound healing2013In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 430, no 3, p. 993-998Article in journal (Refereed)
    Abstract [en]

    Cells move along surfaces both as single cells and multi-cellular units. Recent research points toward pivotal roles for water flux through aquaporins (AQPs) in single cell migration. Their expression is known to facilitate this process by promoting rapid shape changes. However, little is known about the impact on migrating epithelial sheets during wound healing and epithelial renewal. Here, we investigate and compare the effects of AQP9 on single cell and epithelial sheet migration. To achieve this, MDCK-1 cells stably expressing AQP9 were subjected to migration assessment. We found that AQP9 facilitated cell locomotion at both the single and multi-cellular level. Furthermore, we identified major differences in the monolayer integrity and cell size upon expression of AQP9 during epithelial sheet migration, indicating a rapid volume-regulatory mechanism. We suggest a novel mechanism for epithelial wound healing based on AQP-induced swelling and expansion of the monolayer.

  • 7.
    Loitto, Vesa
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Huang, C
    University of North Carolina.
    Jacobson, K A
    University of North Carolina.
    Phosphorylation appears to regulate AQP9-induced filopodium formation in MOLECULAR BIOLOGY OF THE CELL, vol 15, issue S.2004In: MOLECULAR BIOLOGY OF THE CELL, American Society for Cell Biology , 2004, Vol. 15, p. 41A-41AConference paper (Refereed)
    Abstract [en]

    n/a

  • 8.
    Loitto, Vesa
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Huang, Cai
    Sigal, Yury J
    Jacobson, Ken
    Filopodia are induced by aquaporin-9 expression.2007In: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 313, p. 1295-1306Article in journal (Refereed)
    Abstract [en]

      

  • 9.
    Loitto, Vesa
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Karlsson, Thommie
    Linköping University, Department of Clinical and Experimental Medicine. 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.
    Water Flux in Cell Motility: Expanding the Mechanisms of Membrane Protrusion2009In: CELL MOTILITY AND THE CYTOSKELETON, ISSN 0886-1544, Vol. 66, no 5, p. 237-247Article, review/survey (Refereed)
    Abstract [en]

    Transmembrane water fluxes through aquaporins (AQPs) are suggested to play, pivotal roles in cell polarization and directional cell motility. Local dilution by W water influences the dynamics of the subcortical actin polymerization and directs the formation of nascent membrane protrusions. In this paper. recent evidence is discussed in support of such a central role of AQP in membrane protrusion formation, and cell migration as a basis for our Understanding AQP9 Underlying molecular mechanisms of directional motility. Specifically. AQP9 in a physiological context controls transmembrane water fluxes driving, membrane protrusion formation, as an initial cellular response to a chemoattractant or other migratory signals. The importance of AQP-facilitated water fluxes in directional cell motility is underscored the observation that blocking or modifying specific sites in AQP9 also interferes with the molecular machinery that govern actin-mediated cellular shape changes. Cell Motil.

  • 10.
    Loitto, Vesa
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology .
    Dysregulation of aquaporins impairs neutrophil leukocyte motility2003In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 84, no 2, p. 519A-519AConference paper (Other academic)
  • 11.
    Loitto, Vesa
    et al.
    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.
    Hg2+ and small-sized polyethylene glycols have inverse effects on membrane permeability, while both impair neutrophil cell motility2004In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 316, no 2, p. 370-378Article in journal (Refereed)
    Abstract [en]

    Toxic effects after exposure to mercury are well documented in human. Little is, however, known about how Hg2+ affect host defense in general and neutrophil functions in particular. We show here that exposure of human neutrophils to HgCl2 dose-dependently impairs chemoattractant-stimulated motility. Long-term exposure (5-10min) to Hg 2+ yields a rapid influx of extracellular Ca2+ followed by leakage of cytosolic fluorophores, as assessed using fura-2 and ratio imaging microscopy. The inhibition on motility was partly reversible, since pre-treated neutrophils placed in an Hg2+-free environment displayed higher migration rates. The Hg2+-induced fluxes were prevented by addition of small-sized polyethylene glycols (PEG 200-400), which also dose-dependently inhibited neutrophil transmigration. Localized, minute micropipette additions of Hg2+ or PEG caused retraction of the leading edge and redirection of cell migration. Since Hg2+ increases and PEGs decrease membrane permeability in a partially competitive manner, we suggest that the known aquaporin-inhibitor Hg2+ alters membrane permeability by affecting the bidirectional flux through the leukocyte aquaporin-9 (AQP9) while small-sized PEGs yield decreased membrane permeability by becoming trapped in the promiscuous channel. The local additions of Hg 2+ or PEG probably force other cell regions to take over from those with blocked AQPs. Hence, the cells turn direction of motility away from the micromanipulator needle.

  • 12.
    Loitto, Vesa
    et al.
    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.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nitric oxide induces dose-dependent changes in [Ca2+](i), morphology and migration of human neutrophils. in MOLECULAR BIOLOGY OF THE CELL, vol 9, issue , pp 290A-290A1998In: MOLECULAR BIOLOGY OF THE CELL, American Society for Cell Biology , 1998, Vol. 9, p. 290A-290AConference paper (Refereed)
    Abstract [en]

    n/a

  • 13.
    Loitto, Vesa-Matti
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Towards a Refined Model of Neutrophil Motility2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The ability of human polymorphonuclear leukocytes (PMNL; neutrophils), to sense and move to sites of infection is essential for our defense against pathogens. Cell motility is critically dependent on a dynamic remodeling of morphology. The morphological polarization toward chemoattractants, such as N-formyl-Met-Leu-Phe (fMLF), is associated with temporary extension and stabilization of lamellipodia in the direction of movement. The underlying mechanisms of cell motility are, however, still not entirely elucidated. It is therefore an urgent task to extend the present experimental evidence to give solid basis for a comprehensive model. Here it is shown that nitric oxide (NO) stimulates the morphological response of neutrophils, most likely due to transient increases in [Ca2+]i, following addition of NO-donors. This will, hypothetically, activate gelsolin and other actin filament severing proteins, leading to a subsequent decrease in filamentous actin. The incapability to efficiently turnover the actin filament network then blocks all motile activity. It is also shown that N-formyl peptide receptors on polarized neutrophils accumulate non-uniformly towards regions involved in motility. It is suggested that neutrophils use the asymmetric receptor distribution for directional sensing and sustained migration. A model for lamellipodium extension, where water fluxes play a pivotal role is presented. It is suggested that water fluxes through water-selective aquaporin (AQP) channels, contribute to the propulsive force for formation of various membrane protrusions and, thus, cell motility. It is well known that small G proteins of the Rho family GTPases play important roles in the intracellular signaling underlying cell motility. In morphologically polarized neutrophils it is shown that Cdc42, Rac2 and RhoA display spatially distinct distributions, which allows for sequential chemoattractant stimulation of neutrophil motility. The specific localizations of Rac2, Cdc42 and RhoA relative to each other and filamentous actin and fMLF receptors support the hypothesized order of activation and regulation of neutrophil cell motility. In conclusion, the detailed analysis of motility-related issues presented here provide new data allowing further refinement of previous models of neutrophil motility.

    List of papers
    1. Nitric oxide induces dose-dependent CA2+ transients and causes temporal morphological hyperpolarization in human neutrophils
    Open this publication in new window or tab >>Nitric oxide induces dose-dependent CA2+ transients and causes temporal morphological hyperpolarization in human neutrophils
    2000 (English)In: Journal of cellular physiology, ISSN 0021-9541, Vol. 182, no 3, p. 402-413Article in journal (Refereed) Published
    Abstract [en]

    We exposed adherent neutrophils to the nitric oxide (NO)-radical donors S-nitroso-N-acetylpenicillamine (SNAP), S-nitrosoglutathione (GSNO), and sodium nitroprusside (SNP) to study the role of NO in morphology and Ca(2+) signaling. Parallel to video imaging of cell morphology and migration in neutrophils, changes in intracellular free Ca(2+) ([Ca(2+)](i)) were assessed by ratio imaging of Fura-2. NO induced a rapid and persistent morphological hyperpolarization followed by migrational arrest that usually lasted throughout the 10-min experiments. Addition of 0.5-800 microM SNAP caused concentration-dependent elevation of [Ca(2+)](i) with an optimal effect at 50 microM. This was probably induced by NO itself, because no change in [Ca(2+)](i) was observed after treatment with NO donor byproducts, i.e. D-penicillamine, glutathione, or potassium cyanide. Increasing doses of SNAP (>/=200 microM) attenuated the Ca(2+) response to the soluble chemotactic stimulus formyl-methionyl-leucyl-phenylalanine (fMLP), and both NO- and fMLP-induced Ca(2+) transients were abolished at 800 microM SNAP or more. In kinetic studies of fluorescently labeled actin cytoskeleton, NO markedly reduced the F-actin content and profoundly increased cell area. Immunoblotting to investigate the formation of nitrotyrosine residues in cells exposed to NO donors did not imply nitrosylation, nor could we mimic the effects of NO with the cell permeant form of cGMP, i.e., 8-Br-cGMP. Hence these processes were probably not the principal NO targets. In summary, NO donors initially increased neutrophil morphological alterations, presumably due to an increase in [Ca(2+)](i), and thereafter inhibited such shape changes. Our observations demonstrate that the effects of NO donors are important for regulation of cellular signaling, i.e., Ca(2+) homeostasis, and also affect cell migration, e.g., through effects on F-actin turnover. Our results are discussed in relation to the complex mechanisms that govern basic cell shape changes, required for migration.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13604 (URN)10.1002/(SICI)1097-4652(200003)182:3<402::AID-JCP11>3.0.CO;2-D (DOI)
    Available from: 2001-05-25 Created: 2001-05-25 Last updated: 2015-09-18
    2. Assessment of neutrophil N-formyl peptide receptors by using antibodies and fluorescent peptides
    Open this publication in new window or tab >>Assessment of neutrophil N-formyl peptide receptors by using antibodies and fluorescent peptides
    2001 (English)In: Journal of Leukocyte biology, ISSN 0741-5400, Vol. 69, no 5, p. 762-771Article in journal (Refereed) Published
    Abstract [en]

    Enrichment of chemoattractant receptors on the neutrophil surface has been difficult to assess, primarily because of limitations in sensitivity of visualization. Using an ultrasensitive, cooled charge-coupled device camera, we investigated spatial-temporal relationships between N-formyl peptide receptor distribution and directional motility of human neutrophils. Live cells were labeled with fluorescent receptor ligands, i.e., fluoresceinated tert-butyl-oxycarbonyl-Phe-(D)-Leu-Phe-(D)-Leu-Phe-OH (Boc-FLFLF) and formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK), while fixed cells were labeled with either fluorescent peptides or monoclonal antibodies. Double labeling of receptors and filamentous actin (F-actin) was done to investigate possible colocalization. N-Formyl peptide receptors on unstimulated cells were randomly distributed. However, on polarized neutrophils, the receptors accumulated toward regions involved in motility and distributed nonuniformly. In fixed neutrophils, antibody-labeled receptors colocalized with the F-actin-rich leading edge whereas peptide-labeled receptors lagged behind this region. We suggest that neutrophils use an asymmetric receptor distribution for directional sensing and sustained migration. A separation between receptors labeled with peptides and those labeled with antibodies reflects two functionally distinct receptor populations at the membrane of motile neutrophils.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13605 (URN)
    Available from: 2001-05-25 Created: 2001-05-25
    3. Neutrophil leukocyte motility requires directed water influx
    Open this publication in new window or tab >>Neutrophil leukocyte motility requires directed water influx
    Show others...
    2002 (English)In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673, Vol. 71, no 2, p. 212-222Article in journal (Refereed) Published
    Abstract [en]

    The ability of neutrophils to sense and move to sites of infection is essential for our defense against pathogens. For motility, lamellipodium extension and stabilization are prerequisites, but how cells form such membrane protrusions is still obscure. Using contrast-enhanced video microscopy and Transwell® assays, we show that water-selective aquaporin channels regulate lamellipodium formation and neutrophil motility. Addition of anti-aquaporin-9 antibodies, HgCl2, or tetraethyl ammonium inhibited the function(s) of the channels and blocked motility-related shape changes. On human neutrophils, aquaporin-9 preferentially localized to the cell edges, where N-formyl peptide receptors also accumulated, as assessed with fluorescence microscopy. To directly visualize water fluxes at cell edges, cells were loaded with high dilution-sensitive, self-quenching concentrations of fluorophore. In these cells, motile regions always displayed increased fluorescence compared with perinuclear regions. Our observations provide the first experimental support for motility models where water fluxes play a pivotal role in cell-volume increases accompanying membrane extensions.

    Keywords
    aquaporins, anti-aquaporin antibodies, microscopy, HgCl2
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13606 (URN)
    Available from: 2001-05-25 Created: 2001-05-25 Last updated: 2017-12-13
    4. The spatial distribution of RhoA, Rac2 and Cdc42 in human neutrophils allows for sequential chemoattractant stimulation
    Open this publication in new window or tab >>The spatial distribution of RhoA, Rac2 and Cdc42 in human neutrophils allows for sequential chemoattractant stimulation
    2001 (English)In: FEBS Letters, ISSN 0014-5793Article in journal (Refereed) Submitted
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13607 (URN)
    Available from: 2001-05-25 Created: 2001-05-25 Last updated: 2009-04-14
  • 14.
    Loitto, Vesa-Matti
    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.
    Sundqvist, Tommy
    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.
    Gustafsson, Mikael
    Linköping University, Department of Medicine and Care. Linköping University, Faculty of Health Sciences.
    Neutrophil leukocyte motility requires directed water influx2002In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673, Vol. 71, no 2, p. 212-222Article in journal (Refereed)
    Abstract [en]

    The ability of neutrophils to sense and move to sites of infection is essential for our defense against pathogens. For motility, lamellipodium extension and stabilization are prerequisites, but how cells form such membrane protrusions is still obscure. Using contrast-enhanced video microscopy and Transwell® assays, we show that water-selective aquaporin channels regulate lamellipodium formation and neutrophil motility. Addition of anti-aquaporin-9 antibodies, HgCl2, or tetraethyl ammonium inhibited the function(s) of the channels and blocked motility-related shape changes. On human neutrophils, aquaporin-9 preferentially localized to the cell edges, where N-formyl peptide receptors also accumulated, as assessed with fluorescence microscopy. To directly visualize water fluxes at cell edges, cells were loaded with high dilution-sensitive, self-quenching concentrations of fluorophore. In these cells, motile regions always displayed increased fluorescence compared with perinuclear regions. Our observations provide the first experimental support for motility models where water fluxes play a pivotal role in cell-volume increases accompanying membrane extensions.

  • 15.
    Loitto, Vesa-Matti
    et al.
    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.
    The spatial distribution of RhoA, Rac2 and Cdc42 in human neutrophils allows for sequential chemoattractant stimulation2001In: FEBS Letters, ISSN 0014-5793Article in journal (Refereed)
  • 16.
    Loitto, Vesa-Matti
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nilsson, Harriet
    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.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nitric oxide induces dose-dependent CA2+ transients and causes temporal morphological hyperpolarization in human neutrophils2000In: Journal of cellular physiology, ISSN 0021-9541, Vol. 182, no 3, p. 402-413Article in journal (Refereed)
    Abstract [en]

    We exposed adherent neutrophils to the nitric oxide (NO)-radical donors S-nitroso-N-acetylpenicillamine (SNAP), S-nitrosoglutathione (GSNO), and sodium nitroprusside (SNP) to study the role of NO in morphology and Ca(2+) signaling. Parallel to video imaging of cell morphology and migration in neutrophils, changes in intracellular free Ca(2+) ([Ca(2+)](i)) were assessed by ratio imaging of Fura-2. NO induced a rapid and persistent morphological hyperpolarization followed by migrational arrest that usually lasted throughout the 10-min experiments. Addition of 0.5-800 microM SNAP caused concentration-dependent elevation of [Ca(2+)](i) with an optimal effect at 50 microM. This was probably induced by NO itself, because no change in [Ca(2+)](i) was observed after treatment with NO donor byproducts, i.e. D-penicillamine, glutathione, or potassium cyanide. Increasing doses of SNAP (>/=200 microM) attenuated the Ca(2+) response to the soluble chemotactic stimulus formyl-methionyl-leucyl-phenylalanine (fMLP), and both NO- and fMLP-induced Ca(2+) transients were abolished at 800 microM SNAP or more. In kinetic studies of fluorescently labeled actin cytoskeleton, NO markedly reduced the F-actin content and profoundly increased cell area. Immunoblotting to investigate the formation of nitrotyrosine residues in cells exposed to NO donors did not imply nitrosylation, nor could we mimic the effects of NO with the cell permeant form of cGMP, i.e., 8-Br-cGMP. Hence these processes were probably not the principal NO targets. In summary, NO donors initially increased neutrophil morphological alterations, presumably due to an increase in [Ca(2+)](i), and thereafter inhibited such shape changes. Our observations demonstrate that the effects of NO donors are important for regulation of cellular signaling, i.e., Ca(2+) homeostasis, and also affect cell migration, e.g., through effects on F-actin turnover. Our results are discussed in relation to the complex mechanisms that govern basic cell shape changes, required for migration.

  • 17.
    Loitto, Vesa-Matti
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Rasmusson, Birgitta
    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.
    Assessment of neutrophil N-formyl peptide receptors by using antibodies and fluorescent peptides2001In: Journal of Leukocyte biology, ISSN 0741-5400, Vol. 69, no 5, p. 762-771Article in journal (Refereed)
    Abstract [en]

    Enrichment of chemoattractant receptors on the neutrophil surface has been difficult to assess, primarily because of limitations in sensitivity of visualization. Using an ultrasensitive, cooled charge-coupled device camera, we investigated spatial-temporal relationships between N-formyl peptide receptor distribution and directional motility of human neutrophils. Live cells were labeled with fluorescent receptor ligands, i.e., fluoresceinated tert-butyl-oxycarbonyl-Phe-(D)-Leu-Phe-(D)-Leu-Phe-OH (Boc-FLFLF) and formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK), while fixed cells were labeled with either fluorescent peptides or monoclonal antibodies. Double labeling of receptors and filamentous actin (F-actin) was done to investigate possible colocalization. N-Formyl peptide receptors on unstimulated cells were randomly distributed. However, on polarized neutrophils, the receptors accumulated toward regions involved in motility and distributed nonuniformly. In fixed neutrophils, antibody-labeled receptors colocalized with the F-actin-rich leading edge whereas peptide-labeled receptors lagged behind this region. We suggest that neutrophils use an asymmetric receptor distribution for directional sensing and sustained migration. A separation between receptors labeled with peptides and those labeled with antibodies reflects two functionally distinct receptor populations at the membrane of motile neutrophils.

  • 18.
    Lopes, Viviana R
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Loitto, Vesa
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Audinot, Jean‑Nicolas
    Luxembourg Institute of Science and Technology, Luxembourg.
    Bayat, Narges
    Stockholm University, Sweden.
    Gutleb, Arno C.
    Luxembourg Institute of Science and Technology, Luxembourg.
    Cristobal, Susana
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Dose‑dependent autophagic effectof titanium dioxide nanoparticles in humanHaCaT cells at non‑cytotoxic levels2016In: Journal of Nanobiotechnology, ISSN 1477-3155, E-ISSN 1477-3155, Vol. 14, no 22, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Background: Interactions between nanoparticles and cells are now the focus of a fast-growing area of research.Though many nanoparticles interact with cells without any acute toxic responses, metal oxide nanoparticles includingthose composed of titanium dioxide (TiO2-NPs) may disrupt the intracellular process of macroautophagy.Autophagy plays a key role in human health and disease, particularly in cancer and neurodegenerative diseases. Weherein investigated the in vitro biological effects of TiO2-NPs (18 nm) on autophagy in human keratinocytes (HaCaT)cells at non-cytotoxic levels.Results: TiO2-NPs were characterized by transmission electron microscopy (TEM) and dynamic light scatteringtechniques. Cellular uptake, as evaluated by TEM and NanoSIMS revealed that NPs internalization led to the formationof autophagosomes. TiO2-NPs treatment did not reduce cell viability of HaCaT cells nor increased oxidative stress. Cellularautophagy was additionally evaluated by confocal microscopy using eGFP-LC3 keratinocytes, western blottingof autophagy marker LC3I/II, immunodetection of p62 and NBR1 proteins, and gene expression of LC3II, p62, NBR1,beclin1 and ATG5 by RT-qPCR. We also confirmed the formation and accumulation of autophagosomes in NPs treatedcells with LC3-II upregulation. Based on the lack of degradation of p62 and NBR1 proteins, autophagosomes accumulationat a high dose (25.0 μg/ml) is due to blockage while a low dose (0.16 μg/ml) promoted autophagy. Cellularviability was not affected in either case.Conclusions: The uptake of TiO2-NPs led to a dose-dependent increase in autophagic effect under non-cytotoxicconditions. Our results suggest dose-dependent autophagic effect over time as a cellular response to TiO2-NPs. Mostimportantly, these findings suggest that simple toxicity data are not enough to understand the full impact of TiO2-NPsand their effects on cellular pathways or function.

  • 19.
    Molinas, Andrea
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Mirazimi, Ali
    Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden.
    Holm, Angelika
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Loitto, Vesa M.
    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.
    Vikström, Elena
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Protective role of host aquaporin 6 against Hazara virus, a model for Crimean–Congo hemorrhagic fever virus infection2016In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 363, no 8, article id fnw058Article in journal (Refereed)
    Abstract [en]

    Crimean–Congo hemorrhagic fever virus (CCHFV) is an arthropod-borne pathogen that causes infectious disease with severe hemorrhagic manifestations in vascular system in humans. The proper function of the cells in the vascular system is critically regulated by aquaporins (AQP), water channels that facilitate fluxes of water and small solutes across membranes. With Hazara virus as a model for CCHFV, we investigated the effects of viruses on AQP6 and the impact of AQP6 on virus infectivity in host cells, using transiently expressed GFP-AQP6 cells, immunofluorescent assay for virus detection, epifluorescent imaging of living cells and confocal microscopy. In GFP-AQP6 expressing cells, Hazara virus reduced both the cellular and perinuclear AQP6 distribution and changed the cell area. Infection of human cell with CCHFV strain IbAR 10200 downregulated AQP6 expression at mRNA level. Interestingly, the overexpression of AQP6 in host cells decreased the infectivity of Hazara virus, speaking for a protective role of AQP6. We suggest the possibility for AQP6 being a novel player in the virus–host interactions, which may lead to less severe outcomes of an infection.

  • 20.
    Nilsson, Harriet M.
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Annika M.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Loitto, Vesa-Matti
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Svensson, Samuel P.S.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nitric oxide modulates intracellular translocation of pigment organelles in Xenopus laevis melanophores2000In: Cell Motility and the Cytoskeleton, ISSN 0886-1544, E-ISSN 1097-0169, Vol. 47, no 3, p. 209-218Article in journal (Refereed)
    Abstract [en]

    Pigment organelles in Xenopus laevis melanophores are used by the animal to change skin color, and they provide a good model for studying intracellular organelle transport. Movement of organelles and vesicles along the cytoskeleton is essential for many processes, such as axonal transport, endocytosis, and intercompartmental trafficking. Nitric oxide (NO) is a signaling molecule that plays a role in, among other things, relaxation of blood vessels, sperm motility, and polymerization of actin. Our study focused on the effect NO exerts on cytoskeleton-mediated transport, which has previously received little attention. We found that an inhibitor of NO synthesis, N-nitro-L-arginine methyl ester (L-NAME), reduced the melatonin-induced aggregation of the pigment organelles, melanosomes. Preaggregated melanosomes dispersed after treatment with L-NAME but not after exposure to the inactive stereoisomer (D-NAME) or the substrate for NO synthesis (L-arginine). Signal transduction by NO can be mediated through the activation of soluble guanylate cyclase (sGC), which leads to increased production of cGMP and activation of cGMP-dependent kinases (PKG). We found that both the sGC inhibitor 1H-(1,2,4) oxadiazolo(4,3-a)quinoxalin-1-one (ODQ) and the cGMP analogue 8-bromoguanosine 3′:5′-cyclic monophosphate (8-Br-cGMP) reduced melanosome aggregation, whereas the PKG inhibitor KT582 did not. Our results demonstrate that melanosome aggregation depends on synthesis of NO, and NO deprivation causes dispersion. It seems, thus, as if NO and cGMP are essential and can regulate melanosome translocation.

  • 21.
    Turina, Dean
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Loitto, Vesa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Björnström, Karin
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Eintrei, Christina
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Propofol causes neurite retraction in neurons2008Conference paper (Refereed)
  • 22.
    Turina, Dean
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Loitto, Vesa
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Björnström, Karin
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Sundqvist, Tommy
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Eintrei, Christina
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Propofol causes neurite retraction in neurons2008In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 101, no 3, p. 374-379Article in journal (Refereed)
    Abstract [en]

    Background The mechanism by which anaesthetic agents produce general anaesthesia is not yet fully understood. Retraction of neurites is an important function of individual neurones and neural plexuses during normal and pathological conditions, and it has been shown that such a retraction pathway exists in developing and mature neurones. We hypothesized that propofol decreases neuronal activity by causing retraction of neuronal neurites.

    Methods Primary cultures of rat cortical neurones were exposed in concentration– and time–response experiments to 0.02, 0.2, 2, and 20 µM propofol or lipid vehicle. Neurones were pretreated with the GABAA receptor (GABAAR) antagonist, bicuculline, the myosin II ATPase activity inhibitor, blebbistatin, and the F-actin stabilizing agent, phalloidin, followed by administration of propofol (20 µM). Changes in neurite retraction were evaluated using time-lapse light microscopy.

    Results Propofol caused a concentration- and time-dependent reversible retraction of cultured cortical neurone neurites. Bicuculline, blebbistatin, and phalloidin completely inhibited propofol-induced neurite retraction. Images of retracted neurites were characterized by a retraction bulb and a thin trailing membrane remnant.

    Conclusions Cultured cortical rat neurones retract their neurites after exposure to propofol in a concentration- and time-dependent manner. This retraction is GABAAR mediated, reversible, and dependent on actin and myosin II. Furthermore, the concentrations and times to full retraction and recovery correspond to those observed during propofol anaesthesia.

  • 23.
    Vicente Carrillo, Alejandro
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Edebert, I.
    Karlbergsvägen 83 B, Stockholm, Sweden.
    Garside, H.
    AstraZeneca Research and Dev, England.
    Cotgreave, I.
    Karolinska Institute, Sweden; Karolinska Institute, Sweden.
    Rigler, R.
    Karolinska Institute, Sweden.
    Loitto, Vesa
    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.
    Rodriguez-Martinez, Heriberto
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Boar spermatozoa successfully predict mitochondrial modes of toxicity: Implications for drug toxicity testing and the 3R principles2015In: Toxicology in Vitro, ISSN 0887-2333, E-ISSN 1879-3177, Vol. 29, no 3, p. 582-591Article in journal (Refereed)
    Abstract [en]

    Replacement of animal testing by in vitro methods (3-R principles) requires validation of suitable cell models, preferably obtained non-invasively, defying traditional use of explants. Ejaculated spermatozoa are highly dependent on mitochondrial production and consumption of ATP for their metabolism, including motility display, thus becoming a suitable model for capturing multiple modes of action of drugs and other chemicals acting via mitochondrial disturbance. In this study, a hypothesis was tested that the boar spermatozoon is a suitable cell type for toxicity assessment, providing a protocol for 3R-replacement of animals for research and drug-testing. Boar sperm kinetics was challenged with a wide variety of known frank mito-toxic chemicals with previously shown mitochondrial effects, using a semi-automated motility analyser allied with real-time fluorescent probing of mitochondrial potential (MitoTracker and JC-1). Output of this sperm assay (obtained after 30 min) was compared to cell viability (ATP-content, data obtained after 24-48 h) of a hepatome-cell line (HepG2). Results of compound effects significantly correlated (P less than 0.01) for all sperm variables and for most variables in (HepG2). Dose-dependent decreases of relative ATP content in HepG2 cells correlated to sperm speed (r= 0.559) and proportions of motile (r = 0.55) or progressively motile (r = 0.53) spermatozoa. The significance of the study relies on the objectivity of computerized testing of sperm motility inhibition which is comparable albeit of faster output than somatic cell culture models. Sperm suspensions, easily and painlessly obtained from breeding boars, are confirmed as suitable biosensors for preclinical toxicology screening and ranking of lead compounds in the drug development processes.

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