Inhibition of PCSK9 improves the development of pulmonary arterial hypertension via down-regulating Notch3 expression

Abstract

Abstract Background: Pulmonary arterial hypertension (PAH) is a fatal disease characterized by continuous constriction and occlusion of small pulmonary arteries (PA), leading to the development of right ventricular failure and death. PCSK9(Proprotein convertase subtilisin/kexin type 9) is a kind of serine protease enzyme that increases low-density lipoprotein cholesterol (LDLC) levels through degrading low-density lipoprotein cholesterol receptors (LDLr). However, whether inhibition of PCSK9 can alleviate PAH has not been reported. Methods and results: We reported that PCSK9 expression was up-regulated in lung tissues of PAH patients. In addition, we used PCSK9 monoclonal antibody subcutaneously to inhibit PCSK9 expression in mice exposed to chronic hypoxia (10%) in combination with SU5416, a VEGF receptor inhibitor. Hypoxia plus SU5416-induced PAH was attenuated in PCSK9 monoclonal antibody-treated mice compared with wild-type mice. PSCK9 inhibited pulmonary vascular remodeling in mice. Moreover, PCSK9 knockdown significantly altered the proliferation and migration of hypoxia-induced PASMCs. We also found that PCSK9 monoclonal antibody inhibited Notch3 expression in vivo and in vitro experiments. Conclusion: Our results suggest that the PCSK9-Notch3 signaling pathway is critical for the proliferation and migration of PASMCs and provides a potential drug target for the treatment of PAH.