Effect of inhibiting PDHα1 gene expression on the metabolism of fatty liver cells

PDHα1 gene encodes catalytic subunit PDHE1α of pyruvate dehydrogenase (PDH) complex. Based on previous studies, it is hypothesized that inhibition of PDH activity prevents the entry of glycolytic pyruvate into TCA cycle, while promotes fatty acid oxidation and reduces liver triglyceride (TG) level, thereby alleviating nonalcoholic fatty liver disease (NAFLD). In this study, an in vitro model for NAFLD was established with medical fat emulsion; the most effective siRNA for PDHα1 gene was screened out by qPCR technology; the alterations in metabolism of glucose and lipid, and structure & function of mitochondria in the NAFLD cells were primarily evaluated after transfecting PDHα1 siRNA. As the results showed, after inhibiting the expression of PDHα1 gene, glucose level in culture medium was time-dependently increased, and LDH activity in the cells was moderately elevated after 24 h of transfection and then returned to the normal level after 48 h; intracellular TG level was decreased while LPS activity was increased in a time-dependent manner; no significant change in mitochondrial structure was observed with or without siRNA transfection, and ATP content was obviously reduced after 24 h of transfection, followed by restoration after 48 h. It can be concluded that inhibiting PDHα1 gene in fatty liver cells enhances lipid degradation, and represses the utilization of glucose to an extent, thus reducing TG level without impacting energy generation required for cell survival.