College of Medicine, Soochow University, Suzhou, China; Department of Cardiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.
Department of Cardiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.
J Mol Cell Cardiol. 2024 Sep;194:16-31. doi: 10.1016/j.yjmcc.2024.05.013. Epub 2024 May 29.
Hypoxia-induced pulmonary artery hypertension (HPH) is a complication of chronic hypoxic lung disease and the third most common type of pulmonary artery hypertension (PAH). Epigenetic mechanisms play essential roles in the pathogenesis of HPH. N6-methyladenosine (m6A) is an important modified RNA nucleotide involved in a variety of biological processes and an important regulator of epigenetic processes. To date, the precise role of m6A and regulatory molecules in HPH remains unclear.
HPH model and pulmonary artery smooth muscle cells (PASMCs) were constructed from which m6A changes were observed and screened for AlkB homolog 5 (Alkbh5). Alkbh5 knock-in (KI) and knock-out (KO) mice were constructed to observe the effects on m6A and evaluate right ventricular systolic pressure (RVSP), left ventricular and septal weight [RV/(LV + S)], and pulmonary vascular remodeling in the context of HPH. Additionally, the effects of Alkbh5 knockdown using adenovirus were examined in vitro on m6A, specifically in PASMCs with regard to proliferation, migration and cytochrome P450 1A1 (Cyp1a1) mRNA stability.
In both HPH mice lung tissues and hypoxic PASMCs, a decrease in m6A was observed, accompanied by a significant up-regulation of Alkbh5 expression. Loss of Alkbh5 attenuated the proliferation and migration of hypoxic PASMCs in vitro, with an associated increase in m6A modification. Furthermore, Alkbh5 KO mice exhibited reduced RVSP, RV/(LV + S), and attenuated vascular remodeling in HPH mice. Mechanistically, loss of Alkbh5 inhibited Cyp1a1 mRNA decay and increased its expression through an m6A-dependent post-transcriptional mechanism, which hindered the proliferation and migration of hypoxic PASMCs.
The current study highlights the loss of Alkbh5 impedes the proliferation and migration of PASMCs by inhibiting post-transcriptional Cyp1a1 mRNA decay in an m6A-dependent manner.
低氧诱导性肺动脉高压（HPH）是慢性低氧性肺部疾病的并发症，也是第三大常见的肺动脉高压（PAH）类型。表观遗传机制在 HPH 的发病机制中发挥着重要作用。N6-甲基腺苷（m6A）是一种重要的修饰 RNA 核苷酸，参与多种生物学过程，是表观遗传过程的重要调节剂。迄今为止，m6A 及其调节分子在 HPH 中的确切作用仍不清楚。
构建 HPH 模型和肺动脉平滑肌细胞（PASMCs），观察 m6A 的变化，并筛选 AlkB 同源物 5（Alkbh5）。构建 Alkbh5 敲入（KI）和敲除（KO）小鼠，观察 m6A 的影响，并评估 HPH 背景下的右心室收缩压（RVSP）、左心室和室间隔重量[RV/（LV+S）]以及肺血管重构。此外，还在体外使用腺病毒观察 Alkbh5 敲低对 m6A 的影响，特别是在 PASMCs 中对增殖、迁移和细胞色素 P450 1A1（Cyp1a1）mRNA 稳定性的影响。
在 HPH 小鼠肺组织和低氧 PASMCs 中，观察到 m6A 减少，同时 Alkbh5 表达显著上调。体外缺失 Alkbh5 可减弱低氧 PASMC 的增殖和迁移，同时 m6A 修饰增加。此外，Alkbh5 KO 小鼠在 HPH 小鼠中表现出 RVSP、RV/（LV+S）降低和血管重构减弱。机制上，Alkbh5 缺失通过 m6A 依赖性转录后机制抑制 Cyp1a1 mRNA 降解并增加其表达，从而抑制低氧 PASMC 的增殖和迁移。
本研究强调了 Alkbh5 缺失通过 m6A 依赖性方式抑制 Cyp1a1 mRNA 的转录后降解，从而阻碍 PASMC 的增殖和迁移。
