FIGURE 6.

Impact of PCSK9 on CTPR9-induced mitochondrial effects. Adult rat cardiomyocytes were incubated in the presence of LacZ-containing supernatant (control), murine wild-type PCSK9 or GOF PCSK9 (each 0.5 μg/ml) in serum-free medium for 24 h and subsequently treated with CTRP9 (4 μg/ml) for 24 h. (A) Changes in PGC1alpha, Tfam, and ND1 mRNA expression were analyzed by Real-time PCR. (B) Genomic DNA was isolated from the cells and afterward analyzed by Real-time PCR for the expression of a mitochondrial transcript and a nuclear transcript in order to estimate mtDNA content. (C) Citrate synthase (CS) activity and the activity of complex I, complex II and complex IV of the respiratory chain were measured in cardiomyocyte lysates. All values were normalized to total protein content of the samples. All data are mean ± SEM, 4 independent experiments, n = 8 per group, *p < 0.05, **p < 0.01.