Exposure to Succinate Leads to Steatosis in Non-Obese Non-Alcoholic Fatty Liver Disease by Inhibiting AMPK/PPARα/FGF21-Dependent Fatty Acid Oxidation.

Succinate is an important metabolite and a critical chemical with diverse applications in the food, pharmaceutical, and agriculture industries. Recent studies have demonstrated several protective or detrimental functions of succinate in diseases; however, the effect of succinate on lipid metabolism is still unclear. Here, we identified a role of succinate in nonobese nonalcoholic fatty liver disease (NAFLD). Specifically, the level of succinate is increased in the livers and serum of mice with hepatic steatosis. The administration of succinate promotes triglyceride (TG) deposition and hepatic steatosis by suppressing fatty acid oxidation (FAO) in nonobese NAFLD mouse models. RNA-Seq revealed that succinate suppressed fibroblast growth factor 21 (FGF21) expression. Then, the restoration of FGF21 was sufficient to alleviate hepatic steatosis and FAO inhibition induced by succinate treatment in vitro and in vivo. Furthermore, the inhibition of FGF21 expression and FAO mediated by succinate was dependent on the AMPK/PPARα axis. This study provides evidence linking succinate exposure to abnormal hepatic lipid metabolism and the progression of nonobese NAFLD.

Piperine alleviates nonalcoholic steatohepatitis by inhibiting NF-κB-mediated hepatocyte pyroptosis.

PURPOSE: Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD), which has a high risk of cirrhosis, liver failure, and hepatocellular carcinoma. Piperine (Pip) is an extract of plants with powerful anti-inflammatory effects, however, the function of Pip in NASH remains elusive. Here, we aim to explore the role of Pip in NASH and to find the possible mechanisms. METHODS: Methionine and choline-deficient (MCD) diets were used to induce steatohepatitis, methionine- and choline-sufficient (MCS) diets were used as the control. After Pip treatment, H&E staining, Oil Red O staining, hepatic triglyceride (TG) content and F4/80 expression were performed to analysis liver steatosis and inflammation; Masson's staining, COL1A1 and α-SMA were detected liver fibrosis. Lipopolysaccharide (LPS) -treated AML12 cells were used to as the cell model to induce pyroptosis. Then, pyroptosis-related proteins, IL-1ß and LDH release were detected in vivo and in vitro. Finally, NF-κB inhibitor, BAY11-7082, was used to further demonstrate the mechanism of Pip in NASH. RESULTS: The study found that Pip alleviated liver steatosis, inflammation, hepatocyte injury, and fibrosis in mice fed with MCD diets. Moreover, the pyroptosis markers (NLRP3, ASC, caspase-1 p20, and GSDMD), IL-1ß and LDH release were decreased by Pip treatment. NF-κB activation was suppressed by Pip treatment and pyroptosis-related proteins were down regulated by BAY11-7082. CONCLUSION: Pip ameliorates NASH progression, and the therapeutical effect was associated with inhibition of hepatocyte pyroptosis induced by NF-κB.

Effect and potential mechanism of oncometabolite succinate promotes distant metastasis of colorectal cancer by activating STAT3.

To investigate the effect of Oncometabolite succinate on colorectal cancer migration and invasion and to initially explore the underlying mechanism.Succinate acid detection kit detected the succinate content in tissues. The growth of colorectal cancer cells was measured by cck-8 assay, wound-healing migration assay and transwell migration and invasion assays, and then explored the level of epithelial-mesenchymal transition (EMT) and STAT3/ p-STAT3 expression by western blot analysis and quantitative real-time PCR for mRNA expression. We found that succinate levels were significantly higher in carcinoma tissues than paracancerous tissues. After succinate treatment, the colorectal cancer cell lines SW480 and HCT116 had enhanced migration and invasion, the expression of biomarkers of EMT was promoted, and significantly increased phosphorylation of STAT3. In vivo experiments also showed that succinate can increase p-STAT3 expression, promote the EMT process, and promote the distant metastasis of colorectal cancer in mice.Succinate promotes EMT through the activation of the transcription factor STAT3, thus promoting the migration and invasion of colorectal cancer.