FIGURE 2.

Hepatic overexpression of PIAS1 attenuates LXR agonist-induced fatty acid synthesis and up-regulation of lipogenic genes. Primary hepatocytes were infected for 48 h with recombinant adenoviruses encoding EGFP (Ad-EGFP) or FLAG-tagged PIAS1 (Ad-FLAG-PIAS1). Cells were subsequently incubated with DMSO or LXR agonist T0901317 (T0) at 5 μm for 12 h. A, Western immunoblot analysis of PIAS1, LXRα, and LXRβ proteins using the indicated antibodies. α-Tubulin was used as a loading control. B, hepatocytes were cultured in the presence of [¹⁴C]acetate for 17 h. Fatty acid synthesis was measured by the level of conversion of [¹⁴C]acetate into ¹⁴C-labeled intracellular fatty acids (n = 3 independent experiments). C and D, mRNA abundance of Lxrα and Lxrβ (C) or Srebp1c, Acc1, Fas, and Scd1 (D) was analyzed by quantitative RT-PCR using cyclophilin as an internal control (n >3 independent experiments). Data in B–D are shown as means ± S.E. *, p < 0.05 versus T0901317-treated Ad-EGFP-infected cells; #, p < 0.05 versus DMSO-treated Ad-EGFP-infected cells by two-way ANOVA.