Histone demethylase JARID1B regulates proliferation and migration of pulmonary arterial smooth muscle cells in mice with chronic hypoxia-induced pulmonary hypertension via nuclear factor-kappa B (NFkB)

Chronic hypoxia-induced pulmonary hypertension (PH) is a disorder that is characterized by increased pulmonary arterial pressure resulting from lung diseases or shortage of oxygen in the body. Excess proliferation of pulmonary vascular cells such as pulmonary artery endothelial cells (PAECs) and pulmonary artery smooth muscle cells (PASMCs) plays a critical role in the pathogenesis of PH. Recent evidence indicates that, in addition to genetic predisposition and environmental factors, epigenetic mechanisms play a pivotal role in etiology of PH. In this study, we investigated the possible role played by jumonji AT-rich interactive domain 1B (JARID1B), a histone demethylase, in regulating the proliferation of vascular smooth muscle cells in chronic hypoxia-induced PH condition. Quantitative polymerase chain reaction analysis of samples from rats with PH showed an elevated expression of JARID1B in their PASMCs, positively correlating with increased nuclear factor-kappa B (NFkB) expression. Further functional studies in vitro indicated that overexpression of JARID1B increased the proliferation and migration of PASMCs, which were inhibited by depletion of NFkB. Genomewide transcriptional analysis revealed that the JARID1B regulated NFkB signaling pathway by directly binding to its promoter. We have also shown that JARID1B indirectly regulates the expression of vascular endothelial growth factor via NFkB signaling and hence may also play a crucial role in controlling PAECs, leading to changes in vascular architecture in PH. Our findings could lead to further studies on the role of JARID1B in PH etiology and therefore could lead to a potential therapeutic target for chronic hypoxia induced pulmonary hypertension.