Mechanosensitive Ca ²⁺ signaling-mediated lung endothelial cell senescence in pulmonary hypertension

Endothelial dysfunction, driven by cellular senescence and apoptosis, contributes to the development and progression of vascular disease. Cellular senescence is also a hallmark of aging, while the prevalence of pulmonary hypertension (PH) rises with age. Senescent cells acquire the senescence-associated secretory phenotype (SASP) and secrete SASP factors (e.g., pro-inflammatory cytokines, growth factors, and ECM proteases) that stimulate adjacent cells. Elevated cytosolic free Ca 2+ concentration ([Ca 2+ ]cyt) due to augmented Ca 2+ influx and release is implicated in cellular senescence. We previously showed that the mechanosensitive cation channel Piezo1 was upregulated in lung peripheral tissues from animals with experimental PH and in lung vascular endothelial cells (LVECs) from patients with pulmonary arterial hypertension (PAH). Cellular senescence in ECs, determined by upregulation of p53 (TP53), p21WAF1/Cip1 (CDKN1A) and p16INK4A (CDKN2A) as well as activation of senescence-associated β-galactosidase (SA-β-gal), was inhibited by removal of extracellular Ca 2+ and blockade of mechanosensitive cation channels. In this study, we aim to further examine whether Piezo1-mediated Ca 2+ influx contributes to cellular senescence in LVEC. Treatment of human LVECs with doxorubicin (Dox), an inhibitor of DNA replication and repair, increased p53, p21 and p16 as well as pAKT (S473). Prolonged Dox treatment increased the expression of SNAI1, an inducer of endothelial-to-mesenchymal transition (EndMT). Interestingly, Dox also markedly enhanced non-selective cation currents and voltage-gated K+ currents in LVEC. Chelation of intracellular Ca 2+ with BAPTA-AM, a membrane-permeant BAPTA that accumulates in the cytosol and in intracellular Ca 2+ stores and organelles, significantly inhibited Dox-induced increases in p53, p21, p16, and pAKT, while downregulation of Piezo1 by siRNA attenuated Dox-mediated increases in p53 and p21 in LVEC. To examine the effects of SASP factors, we collected conditioned media (CM) from control (vehicle-treated) and senescent (Dox-treated for 24 hrs) LVECs. CM from senescent cells were sufficient to increase p53, p21, p16 and SNAI1 in fresh LVEC. These data indicate that i) Ca 2+ influx through Piezo1 participates in the induction of Dox-mediated LVEC senescence; ii) SASP factors secreted from senescent ECs cause secondary senescence and EndMT in neighboring ECs and proliferation of smooth muscle cells and fibroblasts; and iii) Ca 2+ influx-associated activation of pAKT or AKT/mTORC1 signaling is likely involved in cellular senescence and EndMT in LVEC. Combination therapy targeting endothelial cation channels and EC senescence would be a novel therapeutic strategy for the treatment of PH/PAH and age-associated vascular disease. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.