130 research outputs found

    Assessment of proteolytic degradation of the basement membrane: a fragment of type IV collagen as a biochemical marker for liver fibrosis

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    <p>Abstract</p> <p>Background</p> <p>Collagen deposition and an altered matrix metalloproteinase (MMP) expression profile are hallmarks of fibrosis. Type IV collagen is the most abundant structural basement membrane component of tissue, which increases 14-fold during fibrogenesis in the liver. Proteolytic degradation of collagens by proteases produces small fragments, so-called neoepitopes, which are released systemically. Technologies investigating MMP-generated fragments of collagens may provide more useful information than traditional serological assays that crudely measure total protein. In the present study, we developed an ELISA for the quantification of a neoepitope generated by MMP degradation of type IV collagen and evaluated the association of this neoepitope with liver fibrosis in two animal models.</p> <p>Methods</p> <p>Type IV collagen was degraded <it>in vitro </it>by a variety of proteases. Mass spectrometric analysis revealed more than 200 different degradation fragments. A specific peptide sequence, 1438'GTPSVDHGFL'1447 (CO4-MMP), in the α1 chain of type IV collagen generated by MMP-9 was selected for ELISA development. ELISA was used to determine serum levels of the CO4-MMP neoepitope in two rat models of liver fibrosis: inhalation of carbon tetrachloride (CCl<sub>4</sub>) and bile duct ligation (BDL). The levels were correlated to histological findings using Sirius red staining.</p> <p>Results</p> <p>A technically robust assay was produced that is specific to the type IV degradation fragment, GTPSVDHGFL. CO4-MMP serum levels increased significantly in all BDL groups compared to baseline, with a maximum increase of 248% seen two weeks after BDL. There were no changes in CO4-MMP levels in sham-operated rats. In the CCl<sub>4 </sub>model, levels of CO4-MMP were significantly elevated at weeks 12, 16 and 20 compared to baseline levels, with a maximum increase of 88% after 20 weeks. CO4-MMP levels correlated to Sirius red staining results.</p> <p>Conclusion</p> <p>This ELISA is the first assay developed for assessment of proteolytic degraded type IV collagen, which, by enabling quantification of basement membrane degradation, could be relevant in investigating various fibrogenic pathologies. The CO4-MMP degradation fragment was highly associated with liver fibrosis in the two animal models studied.</p

    Human cytomegalovirus immediate-early 1 protein rewires upstream STAT3 to downstream STAT1 signaling switching an IL6-type to an IFNγ-like response

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    MN and CP were supported by the Wellcome Trust (www.wellcome.ac.uk) Institutional Strategic Support Fund and CP was supported by the Deutsche Forschungsgemeinschaft (PA 815/2-1; www.dfg.de).The human cytomegalovirus (hCMV) major immediate-early 1 protein (IE1) is best known for activating transcription to facilitate viral replication. Here we present transcriptome data indicating that IE1 is as significant a repressor as it is an activator of host gene expression. Human cells induced to express IE1 exhibit global repression of IL6- and oncostatin M-responsive STAT3 target genes. This repression is followed by STAT1 phosphorylation and activation of STAT1 target genes normally induced by IFNγ. The observed repression and subsequent activation are both mediated through the same region (amino acids 410 to 445) in the C-terminal domain of IE1, and this region serves as a binding site for STAT3. Depletion of STAT3 phenocopies the STAT1-dependent IFNγ-like response to IE1. In contrast, depletion of the IL6 receptor (IL6ST) or the STAT kinase JAK1 prevents this response. Accordingly, treatment with IL6 leads to prolonged STAT1 instead of STAT3 activation in wild-type IE1 expressing cells, but not in cells expressing a mutant protein (IE1dl410-420) deficient for STAT3 binding. A very similar STAT1-directed response to IL6 is also present in cells infected with a wild-type or revertant hCMV, but not an IE1dl410-420 mutant virus, and this response results in restricted viral replication. We conclude that IE1 is sufficient and necessary to rewire upstream IL6-type to downstream IFNγ-like signaling, two pathways linked to opposing actions, resulting in repressed STAT3- and activated STAT1-responsive genes. These findings relate transcriptional repressor and activator functions of IE1 and suggest unexpected outcomes relevant to viral pathogenesis in response to cytokines or growth factors that signal through the IL6ST-JAK1-STAT3 axis in hCMV-infected cells. Our results also reveal that IE1, a protein considered to be a key activator of the hCMV productive cycle, has an unanticipated role in tempering viral replication.Publisher PDFPeer reviewe

    New Insight into the Antifibrotic Effects of Praziquantel on Mice in Infection with Schistosoma japonicum

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    Schistosomiasis is a parasitic disease infecting more than 200 million people in the world. Although chemotherapy targeting on killing schistosomes is one of the main strategies in the disease control, there are few effective ways of dealing with liver fibrosis caused by the parasite infection in the chronic and advanced stages of schistosomiasis. For this reason, new strategies and prospective drugs, which exert antifibrotic effects, are urgently required.-induced liver fibrosis was inhibited by PZQ treatment for 30 days. Furthermore, we analyzed the effects of praziquantel on mouse primary hepatic stellate cells (HSCs). It is indicated that mRNA expressions of Col1α1, Col3α1, α-SMA, TGF-β, MMP9 and TIMP1 of HSCs were all inhibited after praziquantel anti-parasite treatments.The significant amelioration of hepatic fibrosis by praziquantel treatment validates it as a promising drug of anti-fibrosis and offers potential of a new chemotherapy for hepatic fibrosis resulting from schistosomiasis

    Role of host genetics in fibrosis

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    Fibrosis can occur in tissues in response to a variety of stimuli. Following tissue injury, cells undergo transformation or activation from a quiescent to an activated state resulting in tissue remodelling. The fibrogenic process creates a tissue environment that allows inflammatory and matrix-producing cells to invade and proliferate. While this process is important for normal wound healing, chronicity can lead to impaired tissue structure and function
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