MEF2A and pulmonary arterial hypertension: Especially, miR-424 and 503 have been revealed as key miRNAs in maintaining homeostasis, the disruption of which lead to the pathogenesis of PAH.43 The authors also demonstrated that selective, pharmacological inhibition of class IIa HDACs using MC1568 restored the impaired MEF2 activity in PAH PAECs and rescued the experimental monocrotaline and SU-5416/hypoxia (SUGEN) PH models, while restoring targets such as miR-424 and 503 (Kim et al.9).