Effects of Fatty Acids on CYP2A5 and Nrf2 Expression in Mouse Primary Hepatocytes

Abnormal fatty acid metabolism is observed throughout nonalcoholic fatty liver disease (NAFLD) pathogenesis, and fatty acid storage is an important inducing factor in insulin resistance, lipid oxidation, hepatic cell damage, and inflammation. During NAFLD pathogenesis, changes in blood and liver contents of different fatty acid types also vary. Cytochrome P450 2A5 (CYP2A5), an important enzyme in mouse liver, metabolizes many drugs and activates multiple pro-carcinogens with widely varying structures. According to the changes in liver fatty acid profiles observed in NAFLD animal models developed in our laboratory and others, saturated (PA/palmitic, and SA/stearic acids) and unsaturated (OA/oleic, LA/linoleic, ALA/α-linolenic and AA/arachidonic acids) fatty acids were selected to induce mouse primary hepatocytes, at concentrations under 1 mM, as detected by MTT assay. After 24 h treatment with various fatty acid concentrations and types, CYP2A5 mRNA and protein amounts, and enzyme activity were determined by real-time PCR, Western blot, and Coumarin 7-hydroxylation, respectively. Meanwhile, Nrf2 mRNA and protein levels were evaluated by real-time PCR and Western blot. The results indicated that saturated fatty acids are more potent in inducing CYP2A5 than unsaturated ones, except arachidonic acid. In addition, the changes in CYP2A5 expression were consistent with the alterations observed in Nrf2 expression, indicating that Nrf2 might play a regulatory role in CYP2A5 expression.