Of distinctively important finding in the present study was that the underlying mechanism of PTU therapy attenuated the MCT‐induced PAH was clearly clarified due to inhibiting the endMT processing up‐regulators (i.e. Jagged1/Jagged2 and Notch1/Notch2) and endMT transcriptional regulators (i.e. GATAs [3, 4, 6]), and upregulating the miR‐200a‐3p/miR‐200c‐3p (i.e. transcriptional repressor), resulting in suppression of the initiation and propagation of endMT and PAH. The gene discussed is NOTCH1; the disease is pulmonary arterial hypertension.