Melanoma Differentiation-Associated Gene 5 Positively Modulates TNF- α-Induced CXCL10 Expression in Cultured HuH-7 and HLE Cells

AbstractThe molecular mechanisms of innate immunity are closely associated with the development of non-alcoholic fatty liver disease (NAFLD). TNF- α is a key cytokine involved in the pathogenesis of metabolic inflammation like NAFLD. Melanoma differentiation-associated gene 5 (MDA5) is a member of the intracellular RNA helicase family proteins that play a pivotal role in an antiviral immune response. Previous studies have demonstrated that TN F-α induces the expression of MDA5 in some types of cells. However, the correlation between TNF-α and the expression of MDA5 in hepatocytes remains unknown. In the present study, we used two human hepatocellular carcinoma cell lines, HuH-7 and HLE, and examined the expression of MDA5 in these cell s upon stimulation with TNF-α. The expression of MDA5 induced by TNF-α was analyzed by quantitative real-time RT-PCR and western blotting. Next, RNA interference against MDA5 was performed and the expressions of CXCL10 and STAT1 were examined. We found that the expression of MDA5 had increased upo n stimulation with TNF-α in a concentration-dependent manner. Gene silencing against MDA5 suppressed the expression of TNF-α-induced CXCL10 in both cells. In HLE cells, gene silencing of MDA5 impaired STAT1 phosphorylation 24 h after stimulation with TNF-α. On the other hand, TNF-α-induced STAT 1 phosphorylation was not detected in HuH-7 cells. These results indicated that MDA5 positively modulated the TNF-α-induced expression of CXCL10 in ...
Source: Inflammation - Category: Allergy & Immunology Source Type: research