Perfluorooctane sulfonate (PFOS), a persistent organic pollutant, is blamed to be associated with the incidence of insulin resistance in the general human population. In this study, the authors found that PFOS inhibited the phosphorylation and activation of protein kinase B (AKT), a key mediator of cellular insulin sensitivity, in human hepatoma HepG2 cells. The mRNA level of the gluconeogenic gene PEPCK, a downstream target gene of AKT, was increased in PFOS-treated cells. Due to stimulated gluconeogenesis, insulin-stimulated glucose uptake was decreased in HepG2 cells. In our previous study, we found that PFOS disturbed autophagy in HepG2 cells. The authors proposed that PFOS could inhibit the activation of AKT through inhibiting mTORC2, a key regulator of autophagy. In this study, levels of triglyceride were found to be increased in HepG2 cells. PFOS-induced accumulation of hepatic lipids also contributed to the inhibition of AKT. Eventually, the inhibition of AKT led to insulin resistance in PFOS-treated cells. The authors concluded that the findings would provide new mechanistic insights into PFOS-induced hepatic insulin resistance.
Authors: Qiu T, Chen M, Sun X, Cao J, Feng C, Li D, Wu W, Jiang L, Yao X. ;Full Source: Biochemical and Biophysical Research Communications. 2016 Jun 27. pii: S0006-291X(16)31062-2. doi: 10.1016/j.bbrc.2016.06.135. [Epub ahead of print] ;