STING Contributes to Pulmonary Hypertension by Targeting IFN and BMPR2 Signaling through Regulating of F2RL3.

Pulmonary hypertension (PH) is an incurable disease characterized by pulmonary vascular remodeling. Endothelial injury and inflammation are the key triggers of disease initiation. Recent findings suggest that STING (stimulator of IFN genes) activation plays a critical role in endothelial dysfunction and IFN signaling. Here, we investigated the involvement of STING in the pathogenesis of PH. Patients with PH and rodent PH model samples, a Sugen 5416/hypoxia PH model, and pulmonary artery endothelial cells (PAECs) were used to evaluate the hypothesis. We found that the cyclic guanosine monophosphate-AMP synthase-STING signaling pathway was activated in lung tissues from rodent PH models and patients with PH and in TNF-α-induced PAECs in vitro. Specifically, STING expression was significantly elevated in the endothelial cells in PH disease settings. In the Sugen 5416/hypoxia mouse model, genetic knockout or pharmacological inhibition of STING prevented the progression of PH. Functionally, knockdown of STING reduced the proliferation and migration of PAECs. Mechanistically, STING transcriptionally regulates its binding partner F2RL3 (F2R-like thrombin or trypsin receptor 3) through the STING-NF-κB axis, which activated IFN signaling and repressed BMPR2 (bone morphogenetic protein receptor 2) signaling both in vitro and in vivo. Further analysis revealed that F2RL3 expression was increased in PH settings and identified negative feedback regulation of F2RL3/BMPR2 signaling. Accordingly, a positive correlation of expression amounts between STING and F2RL3/IFN-stimulated genes was observed in vivo. Our findings suggest that STING activation in PAECs plays a critical role in the pathobiology of PH. Targeting STING may be a promising therapeutic strategy for preventing the development of PH.