Although clinical treatment has significant progress, acute pulmonary embolism is still a common disease with high morbidity and mortality. Janus Kinase 3, a member of JAK family, has been demonstrated to promote smooth muscle cell proliferation through STAT3. In this work, we explored the effect of JANEX-1 (a specific Janus Kinase 3 inhibitor) on platelet-derived growth factor (PDGF)-induced proliferation-related molecules in pulmonary artery smooth muscle cells (PVSMCs) in vitro and assessed the therapeutic potential of Janus Kinase 3 for vascular remodeling in acute pulmonary embolism mice. The results revealed that Janus Kinase 3 was overexpressed and active in PDGF-induced PVSMCs and acute pulmonary embolism mice, compared to a low expression in normal conditions. JANEX-1, blocking Janus Kinase 3 expression or activity, reduced Janus Kinase 3/STAT3 signaling pathway, VEGF expression, FAK activation, and PDGF-induced proliferation of PVSMCs, while overexpression of VEGF or FAK induced PVSMCs proliferation and resisted the negative effects of JANEX-1. Moreover, JANEX-1 improved right ventricular systolic pressure, survival and lung damage in acute pulmonary embolism-mice, and inhibited the thrombus-induced intimal hyperplasia and the expression of α-SMA, VEGF, and FAK activation under neointimal smooth muscle cells of acute pulmonary embolism mice. In conclusion, the data suggest that JANEX-1 exerts protective effects by inhibiting PVSMCs proliferation and vascular remodeling post-acute pulmonary embolism, in part through Janus Kinase 3/STAT3 signaling pathway-mediated VEGF expression and FAK activation. The data are helpful to elucidate the pharmacological mechanism and potential therapeutic effect of JANEX-1 in APE. Impact statement Accumulating evidence suggests that vascular remodeling due to immoderate proliferation and migration of SMCs is a common process occurring in APE. In this work, we tried to find a breakthrough in the pathological mechanism to alleviate the prognosis of APE by improving SMCs proliferation and explored the effect of JANEX-1 on PDGF-induced proliferation-related molecules in PVSMCs and assessed the therapeutic potential of JAK3 for vascular remodeling in APE mice. We demonstrated that JANEX-1, blocking JAK3 expression or activity, reduced JAK3/STAT3 signaling pathway, VEGF expression and FAK activation, and PDGF-induced proliferation of PVSMCs. Moreover, JANEX-1 inhibited the thrombus-induced intimal hyperplasia and the expression of VEGF and FAK activation in neointimal SMCs of APE mice. The data are helpful to elucidate the pharmacological mechanism and potential therapeutic effect of JANEX-1 in APE.
Targeting Janus kinase 3 in mast cells prevents immediate hypersensitivity reactions and anaphylaxis.