RELM-β Augmented Hypoxia-Induced Pulmonary Hypertension Through Interacting with GIPC1, OR1N1 and CLIC4

Pulmonary hypertension (PH) is a clinicopathological syndrome characterized by structural and functional alterations in the pulmonary vasculature arising from heterogeneous etiologies (including hypoxia) and diverse pathogenic mechanisms. These changes elevate pulmonary vascular resistance and increase pulmonary arterial pressure, ultimately progressing to right heart failure and potential fatality. Resistin-like molecule (RELM)-β activates multiple signaling pathways. This study aimed to explore the role of RELM-β in the development of chronic hypoxia-induced PH and its potential mechanisms.

Exogenous human RELM-β was injected into a mouse model of hypoxia for 3 weeks, followed by histological and hemodynamic analyses. The relationship between RELM-β and membrane proteins or receptors (OR1N1, GIPC1 and CLIC4) was determined by affinity purification-mass spectrometry (AP-MS) and co-immunoprecipitation. At the same time, in vitro cell culture experiments were carried out.

Cell membrane proteins or receptors (OR1N1, GIPC1, and CLIC4) were identified as proteins interacting with RELM-β and potentially involving in the development of PH. Compared with the RELM-β overexpression group, siRNA-mediated silencing of OR1N1, GIPC1, or CLIC4 resulted in significant reduction of cell viability in both human pulmonary artery smooth muscle cells (PASMCs) and human pulmonary arterial endothelial cells (PAECs). Moreover, augmenting effect of exogenous RELM-ß on the hypoxia-induced PH was remarkably reduced in the mice with genetic deficiency of GIPC1 (GIPC1 CKO) or CLIC4 (CLIC4 CKO) compared to the wild type mice.

Findings of the current study suggested that RELM-β may play an important role in the development of hypoxia-induced PH through interacting with membrane proteins or receptors, including GIPC1, OR1N1, and CLIC4.