Liver-specific deletion of Ppp2cα enhances glucose metabolism and insulin sensitivity

Protein phosphatase 2A (PP2A) is a key negative regulator of phosphatidylinositol 3-kinase/Akt pathway. Previous study showed that, in the liver, the catalytic subunit of PP2A (PP2Ac) is closely associated with insulin resistance syndrome, which is characterized by glucose intolerance and dyslipidemia. Here we studied the role of liver PP2Ac in glucose metabolism and evaluated whether PP2Ac is a suitable therapeutic target for treating insulin resistance syndrome. Liver-specific Ppp2cα knockout mice (Ppp2cα^loxp/loxp: Alb) exhibited improved glucose homeostasis compared with littermate controls in both normal and high-fat diet conditions, despite no significant changes in body weight and liver weight under chow diet. Ppp2cα^loxp/loxp: Alb mice showed enhanced glycogen deposition, serum triglyceride, cholesterol, low density lipoprotein and high density lipoprotein, activated insulin signaling, decreased expressions of gluconeogenic genes G₆P and PEPCK, and lower liver triglyceride. Liver-specific Ppp2cα knockout mice showed enhanced glucose homeostasis and increased insulin sensitivity by activation of insulin signaling through Akt. These findings suggest that inhibition of hepatic Ppp2cα may be a useful strategy for the treatment of insulin resistance syndrome.