203 research outputs found

    Tissue Localization and Extracellular Matrix Degradation by PI, PII and PIII Snake Venom Metalloproteinases: Clues on the Mechanisms of Venom-Induced Hemorrhage

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    20 páginas, 4 figuras, 3 tablas y 7 tablas en material suplementario.Snake venom hemorrhagic metalloproteinases (SVMPs) of the PI, PII and PIII classes were compared in terms of tissue localization and their ability to hydrolyze basement membrane components in vivo, as well as by a proteomics analysis of exudates collected in tissue injected with these enzymes. Immunohistochemical analyses of co-localization of these SVMPs with type IV collagen revealed that PII and PIII enzymes co-localized with type IV collagen in capillaries, arterioles and post-capillary venules to a higher extent than PI SVMP, which showed a more widespread distribution in the tissue. The patterns of hydrolysis by these three SVMPs of laminin, type VI collagen and nidogen in vivo greatly differ, whereas the three enzymes showed a similar pattern of degradation of type IV collagen, supporting the concept that hydrolysis of this component is critical for the destabilization of microvessel structure leading to hemorrhage. Proteomic analysis of wound exudate revealed similarities and differences between the action of the three SVMPs. Higher extent of proteolysis was observed for the PI enzyme regarding several extracellular matrix components and fibrinogen, whereas exudates from mice injected with PII and PIII SVMPs had higher amounts of some intracellular proteins. Our results provide novel clues for understanding the mechanisms by which SVMPs induce damage to the microvasculature and generate hemorrhage.This work was performed in partial fulfillment of the requirements for the PhD degree for Cristina Herrera at Universidad de Costa Rica.Peer reviewe

    A fractal nature for polymerized laminin

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    Polylaminin (polyLM) is a non-covalent acid-induced nano- and micro-structured polymer of the protein laminin displaying distinguished biological properties. Polylaminin stimulates neuritogenesis beyond the levels achieved by ordinary laminin and has been shown to promote axonal regeneration in animal models of spinal cord injury. Here we used confocal fluorescence microscopy (CFM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) to characterize its three-dimensional structure. Renderization of confocal optical slices of immunostained polyLM revealed the aspect of a loose flocculated meshwork, which was homogeneously stained by the antibody. On the other hand, an ordinary matrix obtained upon adsorption of laminin in neutral pH (LM) was constituted of bulky protein aggregates whose interior was not accessible to the same anti-laminin antibody. SEM and AFM analyses revealed that the seed unit of polyLM was a flat polygon formed in solution whereas the seed structure of LM was highly heterogeneous, intercalating rod-like, spherical and thin spread lamellar deposits. As polyLM was visualized at progressively increasing magnifications, we observed that the morphology of the polymer was alike independently of the magnification used for the observation. A search for the Hausdorff dimension in images of the two matrices showed that polyLM, but not LM, presented fractal dimensions of 1.55, 1.62 and 1.70 after 1, 8 and 12 hours of adsorption, respectively. Data in the present work suggest that the intrinsic fractal nature of polymerized laminin can be the structural basis for the fractal-like organization of basement membranes in the neurogenic niches of the central nervous system.This work was supported by a grant from the Brazilian National Research Council (CNPq; 476772/2008-7) to TCS. MSS acknowledges support from the European Research Council through ERC - 306990. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Hochman Méndez, C.; Cantini ., M.; Moratal Pérez, D.; Salmerón Sánchez, M.; Coelho-Sampaio, T. (2014). A fractal nature for polymerized laminin. PLoS ONE. 9(10):109388-1-109388-11. https://doi.org/10.1371/journal.pone.0109388S109388-1109388-11910Durbeej, M. (2009). Laminins. Cell and Tissue Research, 339(1), 259-268. doi:10.1007/s00441-009-0838-2Miner, J. H., & Yurchenco, P. D. (2004). LAMININ FUNCTIONS IN TISSUE MORPHOGENESIS. Annual Review of Cell and Developmental Biology, 20(1), 255-284. doi:10.1146/annurev.cellbio.20.010403.094555Yurchenco, P. D. (2010). Basement Membranes: Cell Scaffoldings and Signaling Platforms. Cold Spring Harbor Perspectives in Biology, 3(2), a004911-a004911. doi:10.1101/cshperspect.a004911Hohenester, E., & Yurchenco, P. D. (2013). Laminins in basement membrane assembly. Cell Adhesion & Migration, 7(1), 56-63. doi:10.4161/cam.21831Freire, E., & Coelho-Sampaio, T. (2000). Self-assembly of Laminin Induced by Acidic pH. Journal of Biological Chemistry, 275(2), 817-822. doi:10.1074/jbc.275.2.817Freire, E., Sant’Ana Barroso, M. M., Klier, R. N., & Coelho-Sampaio, T. (2011). Biocompatibility and Structural Stability of a Laminin Biopolymer. Macromolecular Bioscience, 12(1), 67-74. doi:10.1002/mabi.201100125Freire, E. (2002). Structure of laminin substrate modulates cellular signaling for neuritogenesis. Journal of Cell Science, 115(24), 4867-4876. doi:10.1242/jcs.00173Hochman-Mendez, C., Lacerda de Menezes, J. R., Sholl-Franco, A., & Coelho-Sampaio, T. (2013). Polylaminin recognition by retinal cells. Journal of Neuroscience Research, 92(1), 24-34. doi:10.1002/jnr.23298Menezes, K., Ricardo Lacerda de Menezes, J., Assis Nascimento, M., de Siqueira Santos, R., & Coelho-Sampaio, T. (2010). Polylaminin, a polymeric form of laminin, promotes regeneration after spinal cord injury. The FASEB Journal, 24(11), 4513-4522. doi:10.1096/fj.10-157628Barroso, M. M. S., Freire, E., Limaverde, G. S. C. S., Rocha, G. M., Batista, E. J. O., Weissmüller, G., … Coelho-Sampaio, T. (2008). Artificial Laminin Polymers Assembled in Acidic pH Mimic Basement Membrane Organization. Journal of Biological Chemistry, 283(17), 11714-11720. doi:10.1074/jbc.m709301200Freire, E. (2004). Sialic acid residues on astrocytes regulate neuritogenesis by controlling the assembly of laminin matrices. Journal of Cell Science, 117(18), 4067-4076. doi:10.1242/jcs.01276Hausdorff, F. (1918). Dimension und �u�eres Ma�. Mathematische Annalen, 79(1-2), 157-179. doi:10.1007/bf01457179Soille, P., & Rivest, J.-F. (1996). On the Validity of Fractal Dimension Measurements in Image Analysis. Journal of Visual Communication and Image Representation, 7(3), 217-229. doi:10.1006/jvci.1996.0020Theiler, J. (1990). Estimating fractal dimension. Journal of the Optical Society of America A, 7(6), 1055. doi:10.1364/josaa.7.001055Otsu, N. (1979). A Threshold Selection Method from Gray-Level Histograms. IEEE Transactions on Systems, Man, and Cybernetics, 9(1), 62-66. doi:10.1109/tsmc.1979.4310076Iranfar, H., Rajabi, O., Salari, R., & Chamani, J. (2012). Probing the Interaction of Human Serum Albumin with Ciprofloxacin in the Presence of Silver Nanoparticles of Three Sizes: Multispectroscopic and ζ Potential Investigation. The Journal of Physical Chemistry B, 116(6), 1951-1964. doi:10.1021/jp210685qPalmero, C. Y., Miranda-Alves, L., Sant’Ana Barroso, M. M., Souza, E. C. L., Machado, D. E., Palumbo-Junior, A., … Nasciutti, L. E. (2013). The follicular thyroid cell line PCCL3 responds differently to laminin and to polylaminin, a polymer of laminin assembled in acidic pH. Molecular and Cellular Endocrinology, 376(1-2), 12-22. doi:10.1016/j.mce.2013.05.020Behrens, D. T., Villone, D., Koch, M., Brunner, G., Sorokin, L., Robenek, H., … Hansen, U. (2012). The Epidermal Basement Membrane Is a Composite of Separate Laminin- or Collagen IV-containing Networks Connected by Aggregated Perlecan, but Not by Nidogens. Journal of Biological Chemistry, 287(22), 18700-18709. doi:10.1074/jbc.m111.336073Colognato, H., Winkelmann, D. A., & Yurchenco, P. D. (1999). Laminin Polymerization Induces a Receptor–Cytoskeleton Network. The Journal of Cell Biology, 145(3), 619-631. doi:10.1083/jcb.145.3.619Liesi, P., & Silver, J. (1988). Is astrocyte laminin involved in axon guidance in the mammalian CNS? Developmental Biology, 130(2), 774-785. doi:10.1016/0012-1606(88)90366-1Zhou, F. C. (1990). Four patterns of laminin-immunoreactive structure in developing rat brain. Developmental Brain Research, 55(2), 191-201. doi:10.1016/0165-3806(90)90200-iGarcia-Abreu, J., Cavalcante, L. A., & Neto, V. M. (1995). Differential patterns of laminin expression in lateral and medial midbrain glia. NeuroReport, 6(5), 761-764. doi:10.1097/00001756-199503270-00014Kazanis, I., & ffrench-Constant, C. (2011). Extracellular matrix and the neural stem cell niche. Developmental Neurobiology, 71(11), 1006-1017. doi:10.1002/dneu.20970Mercier F, Schnack J, Chaumet MSG (2011) Chapter 4 Fractones: home and conductors of the neural stem cell niche. In: Seki, T., Sawamoto, K., Parent, J. M., Alvarez-Buylla, A., (Eds.) Neurogenesis in the adult brain I: neurobiology. Springer. pp 109–133.CAVALCANTIADAM, E., MICOULET, A., BLUMMEL, J., AUERNHEIMER, J., KESSLER, H., & SPATZ, J. (2006). Lateral spacing of integrin ligands influences cell spreading and focal adhesion assembly. European Journal of Cell Biology, 85(3-4), 219-224. doi:10.1016/j.ejcb.2005.09.011Frith, J. E., Mills, R. J., & Cooper-White, J. J. (2012). Lateral spacing of adhesion peptides influences human mesenchymal stem cell behaviour. Journal of Cell Science, 125(2), 317-327. doi:10.1242/jcs.087916Hernández, J. C. R., Salmerón Sánchez, M., Soria, J. M., Gómez Ribelles, J. L., & Monleón Pradas, M. (2007). Substrate Chemistry-Dependent Conformations of Single Laminin Molecules on Polymer Surfaces are Revealed by the Phase Signal of Atomic Force Microscopy. Biophysical Journal, 93(1), 202-207. doi:10.1529/biophysj.106.102491Douet, V., Kerever, A., Arikawa-Hirasawa, E., & Mercier, F. (2013). Fractone-heparan sulphates mediate FGF-2 stimulation of cell proliferation in the adult subventricular zone. Cell Proliferation, 46(2), 137-145. doi:10.1111/cpr.12023Nikolova, G., Strilic, B., & Lammert, E. (2007). The vascular niche and its basement membrane. Trends in Cell Biology, 17(1), 19-25. doi:10.1016/j.tcb.2006.11.005Yurchenco, P. D., Amenta, P. S., & Patton, B. L. (2004). Basement membrane assembly, stability and activities observed through a developmental lens. Matrix Biology, 22(7), 521-538. doi:10.1016/j.matbio.2003.10.006Nikolova, G., Jabs, N., Konstantinova, I., Domogatskaya, A., Tryggvason, K., Sorokin, L., … Lammert, E. (2006). The Vascular Basement Membrane: A Niche for Insulin Gene Expression and β Cell Proliferation. Developmental Cell, 10(3), 397-405. doi:10.1016/j.devcel.2006.01.015Qu, H., Liu, X., Ni, Y., Jiang, Y., Feng, X., Xiao, J., … Zheng, C. (2014). Laminin 411 acts as a potent inducer of umbilical cord mesenchymal stem cell differentiation into insulin-producing cells. Journal of Translational Medicine, 12(1), 135. doi:10.1186/1479-5876-12-135Kanatsu-Shinohara, M., & Shinohara, T. (2013). Spermatogonial Stem Cell Self-Renewal and Development. Annual Review of Cell and Developmental Biology, 29(1), 163-187. doi:10.1146/annurev-cellbio-101512-122353Lander, A. D., Kimble, J., Clevers, H., Fuchs, E., Montarras, D., Buckingham, M., … Oskarsson, T. (2012). What does the concept of the stem cell niche really mean today? 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    The Heterotrimeric Laminin Coiled-Coil Domain Exerts Anti-Adhesive Effects and Induces a Pro-Invasive Phenotype

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    Laminins are large heterotrimeric cross-shaped extracellular matrix glycoproteins with terminal globular domains and a coiled-coil region through which the three chains are assembled and covalently linked. Laminins are key components of basement membranes, and they serve as attachment sites for cell adhesion, migration and proliferation. In this work, we produced a recombinant fragment comprising the entire laminin coiled-coil of the α1-, β1-, and γ1-chains that assemble into a stable heterotrimeric coiled-coil structure independently of the rest of the molecule. This domain was biologically active and not only failed to serve as a substrate for cell attachment, spreading and focal adhesion formation but also inhibited cell adhesion to laminin when added to cells in a soluble form at the time of seeding. Furthermore, gene array expression profiling in cells cultured in the presence of the laminin coiled-coil domain revealed up-regulation of genes involved in cell motility and invasion. These findings were confirmed by real-time quantitative PCR and zymography assays. In conclusion, this study shows for the first time that the laminin coiled-coil domain displays anti-adhesive functions and has potential implications for cell migration during matrix remodeling

    Effects of PI and PIII Snake Venom Haemorrhagic Metalloproteinases on the Microvasculature: A Confocal Microscopy Study on the Mouse Cremaster Muscle

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    The precise mechanisms by which Snake Venom Metalloproteinases (SVMPs) disrupt the microvasculature and cause haemorrhage have not been completely elucidated, and novel in vivo models are needed. In the present study, we compared the effects induced by BaP1, a PI SVMP isolated from Bothrops asper venom, and CsH1, a PIII SVMP from Crotalus simus venom, on cremaster muscle microvasculature by topical application of the toxins on isolated tissue (i.e., ex vivo model), and by intra-scrotal administration of the toxins (i.e., in vivo model). The whole tissue was fixed and immunostained to visualize the three components of blood vessels by confocal microscopy. In the ex vivo model, BaP1 was able to degrade type IV collagen and laminin from the BM of microvessels. Moreover, both SVMPs degraded type IV collagen from the BM in capillaries to a higher extent than in PCV and arterioles. CsH1 had a stronger effect on type IV collagen than BaP1. In the in vivo model, the effect of BaP1 on type IV collagen was widespread to the BM of arterioles and PCV. On the other hand, BaP1 was able to disrupt the endothelial barrier in PCV and to increase vascular permeability. Moreover, this toxin increased the size of gaps between pericytes in PCV and created new gaps between smooth muscle cells in arterioles in ex vivo conditions. These effects were not observed in the case of CsH1. In conclusion, our findings demonstrate that both SVMPs degrade type IV collagen from the BM in capillaries in vivo. Moreover, while the action of CsH1 is more directed to the BM of microvessels, the effects of BaP1 are widespread to other microvascular components. This study provides new insights in the mechanism of haemorrhage and other pathological effects induced by these toxins

    Coronary-Heart-Disease-Associated Genetic Variant at the COL4A1/COL4A2 Locus Affects COL4A1/COL4A2 Expression, Vascular Cell Survival, Atherosclerotic Plaque Stability and Risk of Myocardial Infarction.

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    Genome-wide association studies have revealed an association between coronary heart disease (CHD) and genetic variation on chromosome 13q34, with the lead single nucleotide polymorphism rs4773144 residing in the COL4A2 gene in this genomic region. We investigated the functional effects of this genetic variant. Analyses of primary cultures of vascular smooth muscle cells (SMCs) and endothelial cells (ECs) from different individuals showed a difference between rs4773144 genotypes in COL4A2 and COL4A1 expression levels, being lowest in the G/G genotype, intermediate in A/G and highest in A/A. Chromatin immunoprecipitation followed by allelic imbalance assays of primary cultures of SMCs and ECs that were of the A/G genotype revealed that the G allele had lower transcriptional activity than the A allele. Electrophoretic mobility shift assays and luciferase reporter gene assays showed that a short DNA sequence encompassing the rs4773144 site interacted with a nuclear protein, with lower efficiency for the G allele, and that the G allele sequence had lower activity in driving reporter gene expression. Analyses of cultured SMCs from different individuals demonstrated that cells of the G/G genotype had higher apoptosis rates. Immunohistochemical and histological examinations of ex vivo atherosclerotic coronary arteries from different individuals disclosed that atherosclerotic plaques with the G/G genotype had lower collagen IV abundance and thinner fibrous cap, a hallmark of unstable, rupture-prone plaques. A study of a cohort of patients with angiographically documented coronary artery disease showed that patients of the G/G genotype had higher rates of myocardial infarction, a phenotype often caused by plaque rupture. These results indicate that the CHD-related genetic variant at the COL4A2 locus affects COL4A2/COL4A1 expression, SMC survival, and atherosclerotic plaque stability, providing a mechanistic explanation for the association between the genetic variant and CHD risk

    Molecular composition of the peri-islet basement membrane in NOD mice: a barrier against destructive insulitis

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    Aims/hypothesisThis study examined whether the capsule which encases islets of Langerhans in the NOD mouse pancreas represents a specialised extracellular matrix (ECM) or basement membrane that protects islets from autoimmune attack.MethodsImmunofluorescence microscopy using a panel of antibodies to collagens type IV, laminins, nidogens and perlecan was performed to localise matrix components in NOD mouse pancreas before diabetes onset, at onset of diabetes and after clinical diabetes was established (2-8.5 weeks post-onset).ResultsPerlecan, a heparan sulphate proteoglycan that is characteristic of basement membranes and has not previously been investigated in islets, was localised in the peri-islet capsule and surrounding intra-islet capillaries. Other components present in the peri-islet capsule included laminin chains alpha2, beta1 and gamma1, collagen type IV alpha1 and alpha2, and nidogen 1 and 2. Collagen type IV alpha3-alpha6 were not detected. These findings confirm that the peri-islet capsule represents a specialised ECM or conventional basement membrane. The islet basement membrane was destroyed in islets where intra-islet infiltration of leucocytes marked the progression from non-destructive to destructive insulitis. No changes in basement membrane composition were observed before leucocyte infiltration.Conclusions/interpretationThese findings suggest that the islet basement membrane functions as a physical barrier to leucocyte migration into islets and that degradation of the islet basement membrane marks the onset of destructive autoimmune insulitis and diabetes development in NOD mice. The components of the islet basement membrane that we identified predict that specialised degradative enzymes are likely to function in autoimmune islet damage.H. F. Irving-Rodgers, A. F. Ziolkowski, C. R. Parish, Y. Sado, Y. Ninomiya, C. J. Simeonovic, R. J. Rodger

    In Vitro Study of the Effects of Angiostrongylus cantonensis Larvae Extracts on Apoptosis and Dysfunction in the Blood-Brain Barrier (BBB)

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    It has been hypothesized that blood-brain barrier (BBB) dysfunction in Angiostrongylus cantonensis infection might be due to the apoptosis of the hosts' BBB cells. Here, we evaluated this hypothesis through several methods, all based on an in vitro mouse BBB model consisting of primary culture brain microvascular endothelial cells (BMECs) and brain astrocytic cells (BACs). In the present study, a four-hour percolation and HRP permeability experiment showed that A. cantonensis larvae extracts can increase the permeability of the BBB. Apoptosis among BMECs and BACs after exposure to larvae extracts was monitored by TUNEL and annexin-V-FITC/PI double staining. A. cantonensis larvae extracts were found to induce apoptosis in both BMECs and BACs. For this reason, we concluded that the induction of apoptosis might participate in the BBB dysfunction observed during angiostrongyliasis. Improved fundamental understanding of how A. cantonensis induces apoptosis may lead to new approaches to the treatment or prevention of this parasitic disease

    Genetic Deletion of Laminin Isoforms β2 and γ3 Induces a Reduction in Kir4.1 and Aquaporin-4 Expression and Function in the Retina

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    Glial cells such as retinal Müller glial cells are involved in potassium ion and water homeostasis of the neural tissue. In these cells, inwardly rectifying potassium (Kir) channels and aquaporin-4 water channels play an important role in the process of spatial potassium buffering and water drainage. Moreover, Kir4.1 channels are involved in the maintenance of the negative Müller cell membrane potential. The subcellular distribution of Kir4.1 and aquaporin-4 channels appears to be maintained by interactions with extracellular and intracellular molecules. Laminins in the extracellular matrix, dystroglycan in the membrane, and dystrophins in the cytomatrix form a complex mediating the polarized expression of Kir4.1 and aquaporin-4 in Müller cells.The aim of the present study was to test the function of the β2 and γ3 containing laminins in murine Müller cells. We used knockout mice with genetic deletion of both β2 and γ3 laminin genes to assay the effects on Kir4.1 and aquaporin-4. We studied protein and mRNA expression by immunohistochemistry, Western Blot, and quantitative RT-PCR, respectively, and membrane currents of isolated cells by patch-clamp experiments. We found a down-regulation of mRNA and protein of Kir4.1 as well as of aquaporin-4 protein in laminin knockout mice. Moreover, Müller cells from laminin β2 and γ3 knockout mice had reduced Kir-mediated inward currents and their membrane potentials were more positive than those in age-matched wild-type mice.These findings demonstrate a strong impact of laminin β2 and γ3 subunits on the expression and function of both aquaporin-4 and Kir4.1, two important membrane proteins in Müller cells
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