Dataset Information

Hepatocyte-specific deletion of BAP31 promotes SREBP1C activation, promotes hepatic lipid accumulation, and worsens IR in mice.

ABSTRACT: Conditional knockout mice with targeted disruption of B-cell associated protein (BAP)31 in adult mouse liver were generated and challenged with a high-fat diet (HFD) for 36 or 96 days and markers of obesity, diabetes, and hepatic steatosis were determined. Mutant mice were indistinguishable from WT littermates, but exhibited increased HFD-induced obesity. BAP31-deletion in hepatocytes increased the expression of SREBP1C and the target genes, including acetyl-CoA carboxylase 1 and stearoyl-CoA desaturase-1, and increased hepatic lipid accumulation and HFD-induced liver steatosis. Immunoprecipitation assay showed that BAP31 interacts with SREBP1C and insulin-induced gene 1 (INSIG1), and BAP31-deletion reduces INSIG1 expression, suggesting that BAP31 may regulate SREBP1C activity by modulating INSIG1 protein levels. Additionally, BAP31-deletion induced glucose and insulin intolerance, decreased Akt and glycogen synthase kinase 3? phosphorylation, and enhanced hepatic glucose production in mice. Expression of endoplasmic reticulum (ER) stress markers was significantly induced in BAP31-mutant mice. HFD-induced inflammation was aggravated in mutant mice, along with increased c-Jun N-terminal kinase and nuclear factor-?B activation. These findings demonstrate that BAP31-deletion induces SREBP activation and promotes hepatic lipid accumulation, reduces insulin signaling, impairs glucose/insulin tolerance, and increases ER stress and hepatic inflammation, explaining the protective roles of BAP31 in the development of liver steatosis and insulin resistance in HFD-induced obesity in animal models.

SUBMITTER: Xu JL

PROVIDER: S-EPMC5748495 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Hepatocyte-specific deletion of BAP31 promotes SREBP1C activation, promotes hepatic lipid accumulation, and worsens IR in mice.

Xu Jia-Lin JL Li Li-Ya LY Wang Yan-Qing YQ Li Ya-Qi YQ Shan Mu M Sun Shi-Zhuo SZ Yu Yang Y Wang Bing B

Journal of lipid research 20171107 1

Conditional knockout mice with targeted disruption of B-cell associated protein (BAP)31 in adult mouse liver were generated and challenged with a high-fat diet (HFD) for 36 or 96 days and markers of obesity, diabetes, and hepatic steatosis were determined. Mutant mice were indistinguishable from WT littermates, but exhibited increased HFD-induced obesity. BAP31-deletion in hepatocytes increased the expression of SREBP1C and the target genes, including acetyl-CoA carboxylase 1 and stearoyl-CoA de ...[more]

PMID: 29113994

Similar Datasets

Project description:Background & aimsThere are no studies investigating the direct effects of elevated xanthine oxidase (XO) on lipid metabolism disorders. Here, we aimed to clarify the role of XO in lipid metabolism in a prospective cohort study and elucidate the underlying mechanisms.MethodsThe association between serum XO activity and metabolic associated steatotic liver disease (MASLD) was examined in Cox proportional hazard models in a population-based cohort of 3,358 participants (20-75 years) at baseline. In addition, mouse models were used to investigate the underlying mechanism for the association between overexpression of XO and the lipid metabolism disorders.ResultsAfter an average 5.8 years of follow up, we found elevated serum XO activity was associated with an increased risk of developing MASLD (hazard ratio [HR]: 2.08; 95% CI: 1.44-3.01; p-trend <0.001). Moreover, serum XO activity was significantly associated with serum triglyceride levels (r = 0.68, p <0.001). We demonstrated that hepatic XO expression increased in liver samples from patients with MASLD. Using tissue-specific Xdh knockin mice, we observed rapid lipid metabolism disorders under a high-fat diet rather than a normal chow diet. We found that XO overexpression promotes the absorption of excess dietary fat in the small intestine. Inhibition of XO also significantly reduced the absorption of fat in mice fed a high-fat diet.ConclusionsOur study clarified the association between serum XO activity levels and the development of MASLD in a large population-based prospective cohort study. Furthermore, our mouse models demonstrated that XO overexpression promotes lipid accumulation through mechanisms involving excessive fat absorption by the small intestine.Impact and implicationsUsing a prospective population-based cohort and various animal models, we have identified novel mechanisms by which xanthine oxidase regulates lipid metabolism. Our findings indicate that xanthine oxidase overexpression promotes lipid accumulation by increasing the absorption of excess dietary fat and possibly facilitating lipid transport in vivo. These results could be important for the development of therapies to treat diseases associated with lipid metabolism disorders.

Project description:Background & aimsExploiting key regulators responsible for hepatocarcinogenesis is of great importance for the prevention and treatment of hepatocellular carcinoma (HCC). However, the key players contributing to hepatocarcinogenesis remain poorly understood. We explored the molecular mechanisms underlying the carcinogenesis and progression of HCC for the development of potential new therapeutic targets.MethodsThe Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) and Genotype-Tissue Expression (GTEx) databases were used to identify genes with enhanced expression in the liver associated with HCC progression. A murine liver-specific Ftcd knockout (Ftcd-LKO) model was generated to investigate the role of formimidoyltransferase cyclodeaminase (FTCD) in HCC. Multi-omics analysis of transcriptomics, metabolomics, and proteomics data were applied to further analyse the molecular effects of FTCD expression on hepatocarcinogenesis. Functional and biochemical studies were performed to determine the significance of loss of FTCD expression and the therapeutic potential of Akt inhibitors in FTCD-deficient cancer cells.ResultsFTCD is highly expressed in the liver but significantly downregulated in HCC. Patients with HCC and low levels of FTCD exhibited worse prognosis, and patients with liver cirrhosis and low FTCD levels exhibited a notable higher probability of developing HCC. Hepatocyte-specific knockout of FTCD promoted both chronic diethylnitrosamine-induced and spontaneous hepatocarcinogenesis in mice. Multi-omics analysis showed that loss of FTCD affected fatty acid and cholesterol metabolism in hepatocarcinogenesis. Mechanistically, loss of FTCD upregulated peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element-binding protein 2 (SREBP2) by regulating the PTEN/Akt/mTOR signalling axis, leading to lipid accumulation and hepatocarcinogenesis.ConclusionsTaken together, we identified a FTCD-regulated lipid metabolic mechanism involving PPARγ and SREBP2 signaling in hepatocarcinogenesis and provide a rationale for therapeutically targeting of HCC driven by downregulation of FTCD.Impact and implicationsExploiting key molecules responsible for hepatocarcinogenesis is significant for the prevention and treatment of HCC. Herein, we identified formimidoyltransferase cyclodeaminase (FTCD) as the top enhanced gene, which could serve as a predictive and prognostic marker for patients with HCC. We generated and characterised the first Ftcd liver-specific knockout murine model. We found loss of FTCD expression upregulated peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element-binding protein 2 (SREBP2) by regulating the PTEN/Akt/mTOR signalling axis, leading to lipid accumulation and hepatocarcinogenesis, and provided a rationale for therapeutic targeting of HCC driven by downregulation of FTCD.

Dataset Information

Hepatocyte-specific deletion of BAP31 promotes SREBP1C activation, promotes hepatic lipid accumulation, and worsens IR in mice.

Publications

Hepatocyte-specific deletion of BAP31 promotes SREBP1C activation, promotes hepatic lipid accumulation, and worsens IR in mice.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets