Figure 4. Over-expression of PP4 induces insulin resistance in hepatocytes.
By transfecting the PCMV5-HA-PP4 expression vector into HepG2 cells, we obtained several clonal cell lines (a). PP4 over-expression resulted in reduced glycogen levels (b) and impaired activation of the AKT/GSK3β pathway (c). Similar results were obtained from AD-mediated PP4 over-expression in mouse primary hepatocytes (d). Data represent means ± S.D. (n = 3 independent experiments). #P < 0.05 and ##P < 0.01; the 2 groups are as indicated by the line. T, TNF-α; Con, control; Con AD, control AD.