ABSTRACT
A sedentary lifestyle and physical inactivity leads to metabolic syndrome-associated comorbidities involving abdominal obesity, type 2 diabetes, hyperlipidaemia associated Cardiovascular Diseases (CVDs), and Metabolic dysfunction-associated fatty liver disease (MAFLD). In this study, we evaluated the novel hepato/cardio/adipo-protective role of Quercetin via Vitamin D Receptor, and elucidated its underlying mechanisms in reducing lipotoxicity, inflammation and fibrosis in high calorie diet induced metabolic syndrome. Male Swiss albino mice were fed with western diet and sugar water for multiple time intervals. Anti-lipotoxicity, anti-inflammatory, and anti-fibrotic effect of Quercetin was assessed by Oil Red O, H&E and TMS staining at different time points. The lipid profile, mRNA expression of inflammatory markers (TNF- α, IL-1ß, IL-6 and MCP-1), fibrotic markers (α-SMA, COL1A1, COL1A2), adiponectin, AdipoR2, and VDR expression levels were measured from RNA pools of adipose, liver and heart tissues. Also, lipid-lowering and anti-steatohepatitic effects of Quercetin was assessed using mouse 3T3-L1 adipocytes, rat H9c2 cardiac cells, and human HepG2 hepatocytes. Our results indicate that, western diet fed mice with Quercetin ameliorated lipid profile and lipotoxicity. Histopathological examination and gene expression data revealed that Quercetin reduced hepatic and cardiac inflammation and fibrosis-associated markers. Interestingly, Quercetin treatment increased the serum levels of adiponectin and mRNA expressions of AdipoR2 and VDR. In-vitro experiments revealed the reduction in lipid accumulation of 3T3-L1 and fatty-acid-treated hepatic and cardiac cells following Quercetin treatment. These findings indicate that Quercetin exhibits a protective role on multiple organs through VDR activation and subsequent Adipo/AdipoR2 signaling in metabolic syndrome associated obesity, hepatic injury, and cardiac dysfunction.
ABSTRACT
Metabolic dysfunction-associated steatohepatitis-driven hepatocellular carcinoma (MASH-HCC) is a global clinical challenge for which there is a limited understanding of disease pathogenesis and a subsequent lack of therapeutic interventions. We previously identified that tumor necrosis factor-alpha (TNF-α) upregulated apoptosis antagonizing transcription factor (AATF) in MASH. Here, we investigated the effect of TNF-α converting enzyme (TACE) inhibition as a promising targeted therapy against AATF-mediated steatohepatitis to hepatocarcinogenesis. A preclinical murine model that recapitulates human MASH-HCC was used in the study. C57Bl/6 mice were fed with chow diet normal water (CD) or western diet sugar water (WD) along with a low dose of carbon tetrachloride (CCl4; 0.2 µL·g-1, weekly) for 24 weeks. TACE activity, TNF-α levels, and AATF expression were measured. The mice were treated with the TACE inhibitor Marimastat for 12 weeks, followed by analyses of liver injury, fibrosis, inflammation, and oncogenic signaling. In vitro experiments using stable clones of AATF control and AATF knockdown were also conducted. We found that AATF expression was upregulated in WD/CCl4 mice, which developed severe MASH at 12 weeks and advanced fibrosis with HCC at 24 weeks. WD/CCl4 mice showed increased TACE activity with reduced hepatic expression of sirtuin 1 (Sirt1) and tissue inhibitor of metalloproteinase 3 (Timp3). The involvement of the SIRT1/TIMP3/TACE axis was confirmed by the release of TNF-α, which upregulated AATF, a key molecular driver of MASH-HCC. Interestingly, TACE inhibition by Marimastat reduced liver injury, dyslipidemia, AATF expression, and oncogenic signaling, effectively preventing hepatocarcinogenesis. Furthermore, Marimastat inhibited the activation of JNK, ERK1/2, and AKT, which are key regulators of tumorigenesis in WD/CCl4 mice and in AATF control cells, but had no effect on AATF knockdown cells. This study shows that TACE inhibition prevents AATF-mediated inflammation, fibrosis, and oncogenesis in MASH-HCC, offering a potential target for therapeutic intervention.