BACKGROUND:Senescent cells (SCs) are involved in proliferative disorders, but their role in pulmonary hypertension remains undefined. We investigated SCs in patients with pulmonary arterial hypertension and the role of SCs in animal pulmonary hypertension models.METHODS:We investigated senescence (p16, p21) and DNA damage (γ-H2AX, 53BP1) markers in patients with pulmonary arterial hypertension and murine models. We monitored p16 activation by luminescence imaging in p16-luciferase (p16^LUC/+) knock-in mice. SC clearance was obtained by a suicide gene (p16 promoter–driven killer gene construct in p16-ATTAC mice), senolytic drugs (ABT263 and cell-permeable FOXO4-p53 interfering peptide [FOXO4-DRI]), and p16 inactivation in p16^LUC/LUC mice. We investigated pulmonary hypertension in mice exposed to normoxia, chronic hypoxia, or hypoxia+Sugen, mice overexpressing the serotonin transporter (SM22-5-HTT⁺), and rats given monocrotaline.RESULTS:Patients with pulmonary arterial hypertension compared with controls exhibited high lung p16, p21, and γ-H2AX protein levels, with abundant vascular cells costained for p16, γ-H2AX, and 53BP1. Hypoxia increased thoracic bioluminescence in p16^LUC/+ mice. In wild-type mice, hypoxia increased lung levels of senescence and DNA-damage markers, senescence-associated secretory phenotype components, and p16 staining of pulmonary endothelial cells (P-ECs, 30% of lung SCs in normoxia), and pulmonary artery smooth muscle cells. SC elimination by suicide gene or ABT263 increased the right ventricular systolic pressure and hypertrophy index, increased vessel remodeling (higher dividing proliferating cell nuclear antigen–stained vascular cell counts during both normoxia and hypoxia), and markedly decreased lung P-ECs. Pulmonary hemodynamic alterations and lung P-EC loss occurred in older p16^LUC/LUC mice, wild-type mice exposed to Sugen or hypoxia+Sugen, and SM22-5-HTT⁺ mice given either ABT263 or FOXO4-DRI, compared with relevant controls. The severity of monocrotaline-induced pulmonary hypertension in rats was decreased slightly by ABT263 for 1 week but was aggravated at 3 weeks, with loss of P-ECs.CONCLUSION:Elimination of senescent P-ECs by senolytic interventions may worsen pulmonary hemodynamics. These results invite consideration of the potential impact on pulmonary vessels of strategies aimed at controlling cell senescence in various contexts.

中文翻译：

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消除衰老细胞可促进肺动脉高压的发生和发展

背景：衰老细胞 (SCs) 参与增殖性疾病，但它们在肺动脉高压中的作用仍未明确。我们调查了肺动脉高压患者的 SCs 以及 SCs 在动物肺动脉高压模型中的作用。 . 我们通过 p16-荧光素酶 (p16 ^LUC/+ ) 敲入小鼠的发光成像监测 p16 激活。^{SC 清除是通过自杀基因（p16-ATTAC 小鼠中 p16 启动子驱动的杀伤基因构建体）、衰老药物（ABT263 和细胞渗透性 FOXO4-p53 干扰肽 [FOXO4-DRI]）和 p16 LUC/} p16 失活获得的^卢克老鼠。我们调查了暴露于常氧、慢性缺氧或缺氧+Sugen 的小鼠、过表达血清素转运体 (SM22-5-HTT ⁺ ) 的小鼠以及给予野百合碱的大鼠的肺动脉高压。结果：与对照组相比，肺动脉高压患者表现出高肺动脉压p16、p21 和 γ-H2AX 蛋白水平，丰富的血管细胞与 p16、γ-H2AX 和 53BP1 共染色。缺氧增加了 p16 ^{LUC/+的胸部生物发光}老鼠。在野生型小鼠中，缺氧会增加衰老和 DNA 损伤标志物的肺水平、衰老相关分泌表型成分和肺内皮细胞的 p16 染色（P-EC，正常氧中 30% 的肺 SC）和肺动脉平滑肌肌肉细胞。通过自杀基因或 ABT263 消除 SC 增加了右心室收缩压和肥大指数，增加了血管重塑（在常氧和缺氧期间更高的分裂增殖细胞核抗原染色的血管细胞计数），并显着降低了肺 P-EC。肺血流动力学改变和肺 P-EC 损失发生在较老的 p16 ^LUC/LUC小鼠、暴露于 Sugen 或缺氧 + Sugen 的野生型小鼠和 SM22-5-HTT ⁺与相关对照相比，给予 ABT263 或 FOXO4-DRI 的小鼠。野百合碱诱导的大鼠肺动脉高压的严重程度在 1 周内被 ABT263 轻微降低，但在 3 周时加重，并伴有 P-ECs 丢失。结论：通过 senolytic 干预消除衰老的 P-ECs 可能会恶化肺血流动力学。这些结果需要考虑旨在控制各种情况下细胞衰老的策略对肺血管的潜在影响。