Project description:To investigate the role of hepatic CYP2B in diet-induced nonalcoholic steatohepatitis (NASH), a Cyp2b triple knockout mouse lacking Cyp2b9, Cyp2b10, and Cyp2b13 was developed using CRISPER/Cas9. Wildtype (WT) and Cyp2b-null mice were fed a normal diet (ND) or a choline-deficient, L-amino acid-defined high-fat diet (CDAHFD), containing 0.1% methionine and 62% fat for 8 weeks. RNA was extracted from the livers of female and male mice from all treatment groups and used for RNA seqencing. RNAseq data demonstrated that a lack of Cyp2b was protective in female but more harmful in male mice. Hepatic gene expression revealed a higher number of phase I-III xenobiotic metabolism and inflammatory response genes were down-regulated in CDAHFD-fed WT female and Cyp2b-null male mice.
Project description:Non-alcoholic fatty liver disease (NAFLD) is the number one cause of chronic liver disease worldwide, with 25% of these patients developing nonalcoholic steatohepatitis (NASH). NASH significantly increases the risk of cirrhosis and decompensated liver failure. Past studies in rodent models have shown the knockout of glycine-N-methyltransferase (GNMT) results in rapid pro-gression of steatosis, fibrosis, and hepatocellular carcinoma. However, the attenuation of GNMT in subjects with NASH and the molecular basis for its impact on the disease process are still unclear. To address this knowledge gap, we show the reduction of GNMT protein levels in the liver of NASH subjects compared to healthy controls. To gain insight into the impact of decreased GNMT in the disease process, we performed global label-free proteome studies on the livers from a murine Western diet-based model of NASH. Histological and molecular characterization of the animal model demonstrate high resemblance to the human disease.
Project description:To investigate the effect of aerobic exercise on liver injury in nonalcoholic steatohepatitis (NASH), we established a NASH model induced by atherosclerotic (Ath) diet and intervened with aerobic exercise training.
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.
Project description:Nonalcoholic steatohepatitis (NASH), characterized by hepatic steatosis, inflammation, and liver injury, has become a leading cause of end-stage liver diseases and liver transplantation. Krüppel-like factors 10 (KLF10) is a Cys2/His2 zinc finger transcription factor that regulates cell growth, apoptosis, and differentiation. However, whether it plays a role in the development and progression of chronic liver diseases like NASH remains poorly understood. In the present study, we found that KLF10 expression was selectively upregulated in the mouse models and human patients with NASH, compared with simple steatosis (NAFL). Gain- and loss-of function studies demonstrated that hepatocyte-specific overexpression of KLF10 aggravated, whereas its depletion alleviated diet-induced NASH pathogenesis in mice. Mechanistically, transcriptomic analysis and subsequent functional experiments showed that KLF10 promotes hepatic lipid accumulation and inflammation through the palmitoylation and plasma membrane localization of fatty acid translocase CD36 via transcriptionally activation of zDHHC7. Indeed, both expression of zDHHC7 and palmitoylation of CD36 are required for the pathogenic roles of KLF10 in NASH progression. Thus, our results identify an important role for KLF10 in NAFL-to-NASH development through zDHHC7-mediated CD36 palmitoylation.
Project description:The genomic landscape of hepatic tissue affected by nonalcoholic steatohepatitis (NASH) in severely obese adolescents undergoing bariatric surgery is unknown. Our purpose here was to uncover genomic profiles of obese controls, and obese cases with nonalcoholic fatty liver disease (NAFLD), borderline nonalcoholic steatohepatitis, and definite nonalcoholic steatohepatitis, in order to clarify molecular functions, biological processes, and pathways that are dysregulated in nonalcoholic steatohepatitis in the severely obese adolescent. In a prospective observational cohort study, we have intra-operatively obtained 165 liver samples; of these 67 were submited for microarray analysis. Through ANOVA, we found 8648 genes with differential regulation between the four histologies; from these, we uncovered gene signatures shared between borderline and definite nonalcoholic steatohepatitis, and gene sets with differential effects between borderline and definite.
Project description:Our objective is to determine the role of myeloid FoxO1 in regulating hepatic lipid metabolism and its contribution to nonalcoholic steatohepatitis (NASH) in mice. We generated mice with conditional FoxO1 depletion in myeloid cells, using the FoxO1-LoxP/LysM-Cre system. We then fed myeloid cell-conditional FoxO1-knockout and wild-type male mice a NASH-inducing diet for 25 weeks. Then mice in both groups were euthanized and the liver tissues were procured for the preparation of total RNAs, which were subjected to RNA-seq assay. While myeloid FoxO1 was upregulated in animal models and human subjects with NASH, the underlying mechanism is poorly understood. We found that myeloid cell conditional FoxO1-knockout mice were protected from developing NASH, culminating in the reduction of hepatic inflammation, steatosis and fibrosis. Mechanistically, FoxO1 counteracts Stat6 to skew macrophage polarization from M2 toward M1 signatures to perpetuate hepatic inflammation in NASH. FoxO1 appears as a pivotal mediator of macrophage activation in response to overnutrition and a therapeutic target for ameliorating hepatic inflammation to stem the disease progression from benign steatosis to NASH.
Project description:The mechanisms underlying the progression of non-alcoholic steatohepatitis (NASH) are not completely elucidated. In this study we have integrated gene expression profiling of liver biopsies of NASH patients with translational studies in a mouse model of steatohepatitis and with pharmacological interventions in isolated hepatocytes to identify a novel mechanism implicated in the pathogenesis of NASH. By using high-density oligonucleotide microarray analysis we identified a significant enrichment of known genes involved in the multi-step catalysis of long chain polyunsaturated fatty acids, including delta-5 and 6 desaturases. A combined inhibitor of delta-5 and delta-6 desaturases significantly reduced intracellular lipid accumulation and inflammatory gene expression in isolated hepatocytes. Gas chromatography analysis revealed impaired delta-5 desaturase activity toward the omega-3 pathway in livers from mice with high-fat diet (HFD)-induced NASH. Consistently, restoration of omega-3 index in transgenic fat-1 mice expressing an omega-3 desaturase, which allows the endogenous conversion of omega-6 into omega-3 fatty acids, produced a significant reduction in hepatic insulin resistance, hepatic steatosis, macrophage infiltration and necroinflammatory liver injury, accompanied by attenuated expression of genes involved in inflammation, fatty acid uptake and lipogenesis. These results were comparable to those obtained in a group of mice receiving a HFD supplemented with EPA/DHA. Of interest, hepatocytes from fat-1 mice or supplemented with EPA exhibited synergistic anti-steatotic and anti-inflammatory actions with the delta-5/ delta-6 inhibitor. Conclusion: These findings indicate that both endogenous and exogenous restoration of the hepatic balance between omega-6 and omega-3 fatty acids and/or modulation of desaturase activities exert preventive actions in NASH. The complete database comprised the expression measurements of 18185 genes for liver sample groups: 8 non-alcoholic steatohepatitis (NASH ) and 7 control samples. This dataset is part of the TransQST collection.
Project description:Nonalcoholic steatohepatitis (NASH) is a progressive disorder with aberrant lipid accumulation and subsequent inflammatory and profibrotic response. Lipid reduction through cytoplasmic lipolysis might adversely worsen steatohepatitis, however, the effect of autophagic lipolysis, lipophagy, remains obscure. We engineered the adaptor protein to induce lipophagy with lipid droplet targeting signal and modified LC3 interacting region. Activating hepatocyte lipophagy obviously mitigated both steatosis and NASH pathology. Mechanistically, lipophagy promoted the excretion of lipid from liver via lysosomal exocytosis and attenuated harmful accumulation of nonesterified fatty acid. This exocytosis was dependent on Ca2+ signal unlike the lysosomal dysfunction-related exocytosis. High content compound screening identified alpelisib and digoxin, clinically-approved compounds, as effective activators of lipophagy. Administration of alpelisib or digoxin inhibited the transition to steatohepatitis in mice fed high fat with low methionine low choline diet. Given all these data, activating lipophagy may be a promising therapeutic approach to prevent NASH progression.
Project description:Here, we found that microRNA-223 (miR-223) was highly elevated in hepatocytes after high fat diet (HFD) feeding in mice and in human nonalcoholic steatohepatitis (NASH) samples. Genetic deletion of the miR-223 induced a full spectrum of nonalcoholic fatty liver disease (NAFLD) in mice after long-term (up to one year) HFD feeding including NASH-related steatosis, inflammation, fibrosis and HCC. To better explore the mechanisms underlying the abnormalities observed in HFD-fed miR-223KO mice, we examined hepatic gene expression in 3-month-HFD-fed WT and miR-223KO mice by microarray analysis. Finally, we revealed that miR-223 plays a key role in controlling steatosis-to-NASH progression by inhibiting hepatic Cxcl10 and Taz expression.