SMAD1 and pulmonary arterial hypertension: Having not detected any differences in the transcriptomic nor in the early p-Smad1/5 response to BMP9 or BMP10 in newborn-derived ALK1-mutated ECFCs, we investigated the transcriptomic response in HMVECs carrying ALK1-mutations derived from transplanted sick lungs of two PAH patients (MUT-P1 and -P2, Table 3).