Protein Phosphatase 4 Promotes Hepatocyte Lipoapoptosis by Regulating RAC1/MLK3/JNK Pathway

Figure 1

PP4 expression level was upregulated in palmitate-treated hepatocytes. After treatment with 600 μM palmitate for 48 h, oil red O staining showed lipid accumulation and TUNEL staining showed apoptotic cells in murine primary hepatocytes (a) and HepG2 cells (f) (scale bar: 20 μM). TUNEL-positive dots were measured by the ImageJ software in murine primary hepatocytes (b) and HepG2 cells (g) ( images per group). Apoptosis of murine primary hepatocytes (c) and HepG2 cells (h) was detected by DNA laddering in palmitate-treated cells. Protein levels of PP4, PUMA, Bim, c-caspase 3, and JNK activation were measured by western blot in murine primary hepatocytes (d) and HepG2 cells (i). Relative protein levels were quantified by densitometry using the ImageJ software and normalized to GAPDH in murine primary hepatocytes (e) and HepG2 cells (j). Data are expressed as (), and statistical significance for protein levels was determined by Student’s -test (.