Other prostaglandin receptors are also altered in PAH [55] and we noted that in both CECs and LECs there was increased expression of the PGE2 receptor, EP4 (PTGER4) in CECs (log2FC = 1.43, pAdj = 0.02) and LECs (log2 FC = 1.30, pAdj = 0.005). Here, PTGER4 is linked to pulmonary arterial hypertension.