Potential role of cellular senescence in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare and chronic lung vasculature disease characterised by pulmonary vasculature remodelling, including abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) and dysfunctional endothelial cells (ECs). Remodelling of the pulmonary vasculature occurs from maturity to senescence, and it has become apparent that cellular senescence plays a central role in the pathogenesis of various degenerative vascular diseases and pulmonary pathologies. Cellular senescence represents a state of stable proliferative arrest accompanied by the senescence-associated secretory phenotype (SASP), which entails the copious secretion of proinflammatory signals in the tissue microenvironment. Evidence shows that in PAH patients, higher levels of cytokines, chemokines and inflammatory mediators can be detected and correlate with clinical outcome. Moreover, senescent cells accrue with age in epithelial, endothelial, fibroblastic and immunological compartments within human lungs, and evidence has shown that ECs and PASMCs in lungs from patients with chronic obstructive pulmonary disease were characterised by a higher number of senescent cells. However, there is little evidence uncovering the molecular pulmonary vasculature senescence in PAH. Herein, we review the cellular senescence in pulmonary vascular remodelling, and emphasise its importance in PAH. We further introduce some signalling pathways which might be involved in vasculature senescence and PAH, with the intent to discuss the possibility of the PAH therapy via targeting cellular senescence and reduce PAH progression and mortality.