Fig. 6

PGC-1β knockdown blocked PPARα transcriptional activity in diabetic heart. a Immunoprecipitation with the anti-PPARα (left) or anti-PGC-1β antibody (right) in H9c2 cells, followed by Western blotting with antibodies for anti-PPARα and anti-PGC-1β. b ChIP PCR for analysis of PGC-1β binding activity on the CD36 and PDK4 promoter in H9c2 cells treated with PPARα siRNA or siRNA control. Primers were designed according to PPARα/RXR binding site. c Effect of PGC-1β or miR-30c on PPARα transcriptional activity was evaluated by luciferase reporter assays in H9c2 cells. Cells were first transfected with PGC-1β or miR-30c, and then transfected with pTK-PPREx3-Luc plasmid. d Effect of miR-30c on PPARα transcriptional activity after PGC-1β inhibition was determined by luciferase reporter assays in H9c2 cells. Cells were transfected with miR-30c after PGC-1β inhibition by siRNA, and then transfected pTK-PPREx3-Luc plasmid. e Schematic representation of the association among miR-30c, PGC1β, and abnormality in diabetic heart. In cardiomyocyte of diabetic heart, miR-30c was decreased due to high fatty acid (FA). The loss of miR-30c resulted in PGC1β activation, which enhanced the PPARα transcriptional activity. Upregulated PPARα target genes leaded to glucose-FA use shift, oxidative stress, lipid accumulation, ATP production abnormality and apoptosis, which contributed to the pathologic process of diabetic cardiomyopathy. For c, d, data are representative of three independent experiments and expressed as mean ± SEM, *p < 0.05. ChIP chromatin immunoprecipitation assay, PPRE peroxisome proliferator response element