KLF5 inhibition promotes apoptosis. A) Mitochondrial membrane potential was measured by TMRM in confocal microscopy. PAH- PASMC are more hyperpolarized than control (more red) and KLF5 inhibition (siRNA) depolarized PAH-PASMC. B&C) Apoptosis was also evaluated by TUNEL and Annexin V staining in PASMC. PAH-PASMC are more resistant to starvation induced apoptosis (0, 1%FBS) than control PASMC. KLF5 inhibition in PAH-PASMC promotes apoptosis. D) Survivin expression (measured by Western blot) is increased in PAH-PASMC compared to control cells and KLF5 inhibition (siRNA) decreased survivin expression. Western blot were normalized to SM-actin (*, P < 0.05; ***, P < 0.001).