Finally, either 24 h or 48 h exposure to Sm-p40 was unable to induce apoptosis in HMVEC-L compared to the positive control staurosporine in vitro (Figures 4E, F), suggesting that S. mansoni egg-derived p40 activates TLR4/CD14/py14-Cav-1 signaling pathway, but additional host factors might be required for lung endothelial injury and expansion of the abnormal vascular phenotype observed in PAH. Here, TLR4 is linked to pulmonary arterial hypertension.