The Nutritional Regulation of the AKR1B10 gene in liver fibrosis
Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease associated with obesity and type 2 diabetes mellitus in Western countries. NAFLD is characterized by the accumulation of fat in hepatocytes in the absence of excessive alcohol intake, viral hepatitis, medications or other etiologies for hepatic steatosis leaving the increased risk of NAFLD to high fat and sugar intake. Preliminary RNA sequencing results showed a 10-fold induction of AKR1B10 in fibrotic human liver samples when compared to normal liver samples. AKR1B10 has been shown to be overexpressed in human liver cancer, however, its role in the disease onset of fibrosis or cirrhosis, advanced disease stages of NAFLD, is not known. Our goal was to assess the nutritional regulation of AKR1B10 in liver cells. Active LX-2 cells were treated with either 1% BSA, 0.2, 0.5, or 1 mM palmitate or 5.5, 15, 25 mM glucose for 6, 24, or 48 hours or 0, 5, 10, 20 fructose. RNA and protein isolation techniques followed by real-time PCR and western blotting were used to measure AKR1B10 mRNA and protein expression in the various treatments. AKR1B10 expression had a 50-fold induction in human liver fibrotic samples when compared to normal liver cells. AKR1B10 showed a significant induction of glucose at 15 and 25 mM for 24 hour. Along with an induction of AKR1B10 palmiatte at 1 mM at 6 hour. However, collectively these results show a reduction in AKR1B10 expression in response to exposure to fructose, glucose, and palmitate. Future studies will be needed to optimize the sugar and fat concentrations for induction of AKR1B10 and longer exposure time frame.