Department of Respiratory Medicine, Hunan Provincial People's Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, China.
Department of Cardiovascular Medicine, Hunan Provincial People's Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, China.
FASEB J. 2024 Feb 15;38(3):e23452. doi: 10.1096/fj.202301563R.
Autophagy is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). We aimed to investigate whether the p62-Keap1-Nrf2 pathway affects the development of PAH by mediating autophagy. A PAH rat model was established using monocrotaline (MCT). Pulmonary artery smooth muscle cells (PASMCs) were extracted, and the changes in proliferation, migration, autophagy, and oxidative stress were analyzed following overexpression or knockdown of p62. The impact of p62 on the symptoms of PAH rats was assessed by the injection of an adenovirus overexpressing p62. We found that the knockdown of p62 increased the proliferation and migration of PASMCs, elevating the oxidative stress of PASMCs and upregulating gene expression of NADPH oxidases. Co-IP assay results demonstrated that p62 interacted with Keap1. p62 knockdown enhanced Keap1 protein stability and Nrf2 ubiquitination. LC3II/I and ATG5 were expressed more often when p62 was knocked down. Treating with an inhibitor of autophagy reversed the impact of p62 knockdown on PASMCs. Nrf2 inhibitor treatment reduced the expression of Nrf2 and p62, while increasing the expression of Keap1, LC3II/I, and ATG5 in PASMCs. However, overexpressing p62 diminished mRVP, SPAP, and Fulton index in PAH rats and attenuated pulmonary vascular wall thickening. Overexpression of p62 also decreased the expression of Keap1, LC3II/I, and ATG5 and increased the nuclear expression of Nrf2 in PAH rats. Importantly, overexpression of p62 reduced oxidative stress and the NADPH oxidase expression in PAH rats. Overall, activation of the p62-Keap1-Nrf2 positive feedback signaling axis reduces the proliferation and migration of PASMCs and alleviates PAH by inhibiting autophagy and oxidative stress.
自噬参与肺动脉高压（PAH）的发病机制。我们旨在研究 p62-Keap1-Nrf2 通路是否通过介导自噬影响 PAH 的发展。使用单环素来建立 PAH 大鼠模型（MCT）。提取肺动脉平滑肌细胞（PASMC），并在过表达或敲低 p62 后分析其增殖、迁移、自噬和氧化应激的变化。通过注射过表达 p62 的腺病毒来评估 p62 对 PAH 大鼠症状的影响。我们发现，敲低 p62 增加了 PASMC 的增殖和迁移，增加了 PASMC 的氧化应激并上调了 NADPH 氧化酶的基因表达。Co-IP 检测结果表明 p62 与 Keap1 相互作用。p62 敲低增强了 Keap1 蛋白稳定性和 Nrf2 泛素化。当 p62 被敲低时，LC3II/I 和 ATG5 的表达更为频繁。用自噬抑制剂处理逆转了 p62 敲低对 PASMC 的影响。Nrf2 抑制剂处理降低了 PASMC 中 Nrf2 和 p62 的表达，而增加了 Keap1、LC3II/I 和 ATG5 的表达。然而，过表达 p62 减少了 PAH 大鼠的 mRVP、SPAP 和 Fulton 指数，并减轻了肺血管壁增厚。过表达 p62 还降低了 Keap1、LC3II/I 和 ATG5 的表达，增加了 PAH 大鼠中 Nrf2 的核表达。重要的是，过表达 p62 减少了 PAH 大鼠的氧化应激和 NADPH 氧化酶表达。总之，激活 p62-Keap1-Nrf2 正反馈信号通路通过抑制自噬和氧化应激减少 PASMC 的增殖和迁移，并缓解 PAH。
