TLR3 and pulmonary hypertension: Consistent with a protective role of TLR3 against PH development, TLR3−/− mice exhibited more severe pulmonary hypertension upon exposure to chronic hypoxia/SU5416 while TLR3 activation using a high-dose synthetic ligand of dsRNA, polyinosinic:polycytidylic acid (poly[I:C]), reduced established experimental PH in two rat models [71,72].