PPARGC1A and endothelial dysfunction: As expected, we showed that knockdown of PGC1-α (Figure 6A,C) or inhibition of AMPK (Figure 6B,D) counteracted CTRP9-mediated antioxidant enzymes inductions including HO-1, NQO-1, GCLC, and GCLM, indicating that antioxidant-dependent mechanisms were involved in the beneficial effects of CTRP9 against endothelial dysfunction with regard to ox-LDL stimulation.