One study shows that H19 is downregulated in MCT‐induced PAH rats, and melatonin can upregulate it, leading to the binding of H19 with miR‐200a, which subsequently upregulates programmed cell death 4 (PDCD4) and promotes apoptosis of PAMSCs [287]. This evidence concerns the gene PDCD4 and pulmonary arterial hypertension.