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Advanced glycation endproducts induce fibrogenic activity in nonalcoholic steatohepatitis by modulating TNF-?-converting enzyme activity in mice.

ABSTRACT: Advanced glycation endproducts (AGEs) accumulate in patients with diabetes, yet the link between AGEs and inflammatory and fibrogenic activity in nonalcoholic steatohepatitis (NASH) has not been explored. Tumor necrosis factor alpha (TNF-?)-converting enzyme (TACE) is at the center of inflammatory processes. Because the main natural regulator of TACE activity is the tissue inhibitor of metalloproteinase 3 (Timp3), we hypothesized that AGEs induce TACE through nicotinamide adenine dinucleotide phosphate reduced oxidase 2 (NOX2); and the down-regulation of Sirtuin 1 (Sirt1)/Timp3 pathways mediate fibrogenic activity in NASH. The role of NOX2, Sirt1, Timp3, and TACE was evaluated in choline-deficient L-amino acid defined (CDAA) or Western diet (WD)-fed wild-type (WT) and NOX2(-/-) mice. To restore Timp3, mice were injected with adenovirus (Ad)-Timp3. Sirt1 and Timp3 expressions were studied in livers from NASH patients, and we found that their levels were significantly lower than in healthy controls. In WT mice on the CDAA or WD, Sirt1 and Timp3 expressions were lower, whereas production of reactive oxidative species and TACE activity significantly increased with an increase in active TNF-? production as well as induction of fibrogenic transcripts. Ad-Timp3 injection resulted in a significant decline in TACE activity, procollagen ?1 (I), alpha smooth muscle actin (?-SMA) and transforming growth factor beta (TGF-?) expression. NOX2(-/-) mice on the CDAA or WD had no significant change in Sirt1, Timp3, and TACE activity or the fibrosis markers assessed. In vitro, AGE exposure decreased Sirt1 and Timp3 in hepatic stellate cells by a NOX2-dependent pathway, and TACE was induced after exposure to AGEs.TACE activation is central to the pathogenesis of NASH and is mediated by AGEs through NOX2 induction and down-regulation of Sirt1/Timp3 pathways.

SUBMITTER: Jiang JX

PROVIDER: S-EPMC3897213 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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Advanced glycation endproducts induce fibrogenic activity in nonalcoholic steatohepatitis by modulating TNF-α-converting enzyme activity in mice.

Jiang Joy X JX Chen Xiangling X Fukada Hiroo H Serizawa Nobuko N Devaraj Sridevi S Török Natalie J NJ

Hepatology (Baltimore, Md.) 20130806 4

<h4>Unlabelled</h4>Advanced glycation endproducts (AGEs) accumulate in patients with diabetes, yet the link between AGEs and inflammatory and fibrogenic activity in nonalcoholic steatohepatitis (NASH) has not been explored. Tumor necrosis factor alpha (TNF-α)-converting enzyme (TACE) is at the center of inflammatory processes. Because the main natural regulator of TACE activity is the tissue inhibitor of metalloproteinase 3 (Timp3), we hypothesized that AGEs induce TACE through nicotinamide aden ...[more]

PMID: 23703665

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Project description:BackgroundThe traditional Chinese medicine prescription, Qianggan formula have been confirmed to be effective on non-alcoholic steatohepatitis (NASH), however, the underlying molecular mechanisms remain obscure.MethodsThirty-six male C57BL/6 mice were randomly divided into three groups: normal chow diet group; methionine-and-choline-deficient diet (MCD) group, and Qianggan extract (QG) intervention group (0.4 g/kg daily) that fed with MCD. The efficacy of QG was biochemically and histologically evaluated. The expression profiles of messenger ribonucleic acids (mRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) were examined using microarray and verified by RT-qPCR.ResultsQG significantly improved the phenotypic characteristics of NASH, as serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) levels and liver inflammatory cytokines were significantly decreased. By the cutoff of a 1.5-fold change and P < 0.05, 6193 mRNAs, 5692 lncRNAs and 4843 circRNAs were identified as differentially expressed between the MCD and normal groups, and 514 mRNAs, 1182 lncRNAs and 443 circRNAs were identified as differentially expressed between the QG and MCD groups. The intersections (244 mRNAs, 259 lncRNAs and 98 circRNAs) among the three groups were chosen for analysis. Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment revealed that most overlapping mRNAs were related to immune functions such as natural-killer-cell-mediated cytotoxicity, intestinal immune network for IgA production, and T cell receptor signaling pathway. Pathway interactions, protein-protein interactions and molecular complex detection (MCODE) analysis identified numerous immune-related hub genes e.g. natural cytotoxicity triggering receptor 1(Ncr1), C-X-C motif chemokine ligand 9 (Cxcl9), Klra1, and Cd28. Finally, two lncRNAs (Sngh1 and Slc36a3os) and four circRNAs (circ_0009029, circ_0004572, circ_0009212 and circ_0009453) in competing endogenous RNA (ceRNA) networks were constructed by Cytoscape, and immune-related mRNAs (e.g., Cd28, Cd8a, Il15, and Klrk1) were involved in the ceRNA networks.ConclusionsLncRNA and circRNA-associated immune ceRNA networks might be the targets of QG in alleviating NASH, and our work may provide valuable clues for exploring the mechanisms underlying the effect of QG.

Project description:The pathological progression of nonalcoholic fatty liver disease (NAFLD) is driven by multiple factors, and nonalcoholic steatohepatitis (NASH) represents its progressive form. In our previous studies, we found that bicyclol had beneficial effects on NAFLD/NASH. Here we aim to investigate the underlying molecular mechanisms of the bicyclol effect on NAFLD/NASH induced by high-fat diet (HFD) feeding. A mice model of NAFLD/NASH induced by HFD-feeding for 8 weeks was used. As a pretreatment, bicyclol (200 mg/kg) was given to mice by oral gavage twice daily. Hematoxylin and eosin (H&E) stains were processed to evaluate hepatic steatosis, and hepatic fibrous hyperplasia was assessed by Masson staining. Biochemistry analyses were used to measure serum aminotransferase, serum lipids, and lipids in liver tissues. Proteomics and bioinformatics analyses were performed to identify the signaling pathways and target proteins. The real-time RT-PCR and Western blot analyses were performed to verify the proteomics data. As a result, bicyclol had a markedly protective effect against NAFLD/NASH by suppressing the increase of serum aminotransferase, hepatic lipid accumulation and alleviating histopathological changes in liver tissues. Proteomics analyses showed that bicyclol remarkably restored major pathways related to immunological responses and metabolic processes altered by HFD feeding. Consistent with our previous results, bicyclol significantly inhibited inflammation and oxidative stress pathway related indexes (SAA1, GSTM1 and RDH11). Furthermore, the beneficial effects of bicyclol were closely associated with the signaling pathways of bile acid metabolism (NPC1, SLCOLA4 and UGT1A1), cytochrome P450-mediated metabolism (CYP2C54, CYP2C70 and CYP3A25), biological processes such as metal ion metabolism (Ceruloplasmin and Metallothionein-1), angiogenesis (ALDH1A1) and immunological responses (IFI204 and IFIT3). These findings suggested that bicyclol is a potential preventive agent for NAFLD/NASH by targeting multiple mechanisms in future clinical investigations.

Dataset Information

Advanced glycation endproducts induce fibrogenic activity in nonalcoholic steatohepatitis by modulating TNF-?-converting enzyme activity in mice.

Publications

Advanced glycation endproducts induce fibrogenic activity in nonalcoholic steatohepatitis by modulating TNF-α-converting enzyme activity in mice.

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