Figure 5

Pioglitazone (PGZ) upregulated mitochondrial respiratory chain (MRC) subunit gene expression in C57BL/6J mice and HepG2 cells. (A) Gene expression of representative subunits of complex I (MTND1, MTND2, MTND4, MTND4L, NDUFA9, NDUFS3, NDUFB6), complex II (SDHA), complex III (UQCRC1, UQCRC2, UQCRF1), complex IV (COX4) subunits, and β-actin was measured by quantitative real-time polymerase chain reaction (RT-PCR) in the liver from ten PGZ-treated and ten untreated C57BL/6J mice. The subunit mRNA/β-actin mRNA ratio was calculated. Data are expressed as fold change over control mice. NS, not significant. (B) Gene expression of subunits of complex I (NDUFA9, NDUFS3, NDUFB6), II (SDHA), III (UQCRC1, UQCRC2, UQCRF1), and IV (COX4) was measured in HepG2 cells treated with 10 μM PGZ for 5 days. Messenger RNA (mRNA) of subunits was analyzed by RT-PCR following the procedure described in the Methods section. The subunit/β-actin mRNA ratio was calculated. Data are expressed as fold change over control cells. NS, not significant. (C) ATP content in HepG2 cells treated with 10 μM PGZ for 5 days. Data are representative of one experiment that was repeated by quintuplicate four times with similar results. (D,E) Effects of PGZ on estrogen-related receptor α (ERRα), specific protein 1 (Sp1) and peroxisome-proliferator activated receptor (PPAR)γ coactivator 1α (PGC-1α) gene expression in HepG2 cells and mice. (D) HepG2 cells were treated with 10 μM PGZ for 5 days. Messenger RNAs of ERRα, Sp1, and PGC1α were analyzed by RT-PCR following the procedure described in the Methods section. The subunit/β-actin mRNA ratio was calculated. Data are expressed as fold change over control cells. NS, not significant. (E) ERRα, Sp1, and PGC1α gene expression was analyzed by RT-PCR in the liver of mice treated with 10 mg/kg/day PGZ for 12 weeks. NS, not significant.