Farkas and colleagues [71] demonstrated that TLR3 expression is significantly decreased in pulmonary artery endothelial cells (PAECs), remodeled pulmonary arteries, and lung tissue of patients with PH and show that TLR3 deficiency increases susceptibility to apoptosis and pulmonary hypertension in vitro and in vivo. This evidence concerns the gene TLR3 and pulmonary arterial hypertension.