To further confirm the functional role of BMPER in vivo, we investigated whether human recombinant BMPER (hrBMPER) incubation could rescue endoglin deficiency in vitro. Previous reports showed that ECs differentiated from iPSCs derived from patients could be applied to study the molecular pathology of pulmonary arterial hypertension [38]. Here, BMPER is linked to pulmonary arterial hypertension.