PDK1 and pulmonary arterial hypertension: Studies show that in PAH PAECs, both HIF-1α and HIF-2α contribute to modify the metabolic phenotypes by regulating the expression of mitochondrial enzymes such as pyruvate dehydrogenase kinase 1 (PDK1), lactate dehydrogenase A (LDHA), Hexokinase 1,2 (HK1,2) and Glucose transporter 1,3 (GLUT1,3) to regulate Warburg effect (aerobic glycolysis) and anerobic glycolysis (33, 34).