Affiliated Eye Hospital, Nanjing Medical University, Nanjing, China; The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing, China.
Affiliated Eye Hospital, Nanjing Medical University, Nanjing, China; The Fourth School of Clinical Medicine, Nanjing Medical University, Nanjing, China.
Exp Cell Res. 2024 Nov 1;443(1):114291. doi: 10.1016/j.yexcr.2024.114291. Epub 2024 Oct 24.
Pathological retinal neovascularization (RNV) is a prevalent characteristic of various ocular diseases, including proliferative diabetic retinopathy (PDR), retinopathy of prematurity (ROP), and retinal vein occlusion (RVO). While the importance of N6-methyladenosine (m6A) modification in diverse disease contexts is well-established, its functional role in pathological RNV remains unclear. Herein, we investigated the involvement of m6A modification and its core methyltransferase, METTL14, in a model of oxygen-induced retinopathy (OIR) to elucidate their contribution to retinal angiogenesis. In this study, we observed heightened levels of m6A modification and elevated expression of METTL14 in the OIR model, suggesting their potential implication in pathological RNV. Employing targeted knockdown of METTL14, we revealed that its depletion activated autophagy flux in human retinal vascular endothelial cells (HRVECs), consequently inhibiting the angiogenic capacity of endothelial cells. Mechanistically, we demonstrated that METTL14 exerts its regulatory influence on autophagy flux by modulating the stability of ATG7, a pivotal protein involved in autophagy. Specifically, METTL14 knockdown led to increased ATG7 expression at both mRNA and protein levels, accompanied by reduced m6A methylation of ATG7 mRNA and enhanced mRNA stability. Moreover, silencing of ATG7 counteracted the effects of METTL14 knockdown on endothelial cell functions, emphasizing ATG7 as a downstream target of METTL14-mediated autophagy in HRVECs. After all, our findings provide valuable insights into the pathogenesis of retinal pathological angiogenesis and potential therapeutic targets for the treatment of ocular neovascular diseases.
病理性视网膜新生血管（RNV）是多种眼病的普遍特征，包括增生性糖尿病视网膜病变（PDR）、早产儿视网膜病变（ROP）和视网膜静脉阻塞（RVO）。虽然 N6-甲基腺苷（m6A）修饰在各种疾病中的重要性已得到充分证实，但它在病理性 RNV 中的功能作用尚不清楚。在此，我们研究了 m6A 修饰及其核心甲基转移酶 METTL14 在氧诱导的视网膜病变（OIR）模型中的作用，以阐明其在视网膜血管生成中的作用。在这项研究中，我们观察到 OIR 模型中 m6A 修饰水平升高和 METTL14 表达升高，表明它们可能参与病理性 RNV。通过靶向敲低 METTL14，我们发现其耗竭可激活人视网膜血管内皮细胞（HRVEC）中的自噬流，从而抑制内皮细胞的血管生成能力。从机制上讲，我们证明 METTL14 通过调节自噬关键蛋白 ATG7 的稳定性来发挥对自噬流的调节作用。具体来说，METTL14 敲低导致 ATG7 的 mRNA 和蛋白水平表达增加，同时 ATG7 mRNA 的 m6A 甲基化减少和 mRNA 稳定性增强。此外，沉默 ATG7 可逆转 METTL14 敲低对内皮细胞功能的影响，强调了 ATG7 作为 METTL14 介导的 HRVEC 自噬下游靶点的作用。总之，我们的研究结果为视网膜病理性血管生成的发病机制提供了有价值的见解，并为眼部新生血管疾病的治疗提供了潜在的治疗靶点。
