Division of Cardiac Surgery, Cardiovascular Diseases Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510080, China.
National-Guangdong Joint Engineering Laboratory for Diagnosis and Treatment of Vascular Diseases, Guangzhou, 510080, China.
Sci China Life Sci. 2024 Feb;67(2):286-300. doi: 10.1007/s11427-022-2381-7. Epub 2023 Oct 25.
We previously demonstrated that normal high-density lipoprotein (nHDL) can promote angiogenesis, whereas HDL from patients with coronary artery disease (dHDL) is dysfunctional and impairs angiogenesis. Autophagy plays a critical role in angiogenesis, and HDL regulates autophagy. However, it is unclear whether nHDL and dHDL regulate angiogenesis by affecting autophagy. Endothelial cells (ECs) were treated with nHDL and dHDL with or without an autophagy inhibitor. Autophagy, endothelial nitric oxide synthase (eNOS) expression, miRNA expression, nitric oxide (NO) production, superoxide anion (O) generation, EC migration, and tube formation were evaluated. nHDL suppressed the expression of miR-181a-5p, which promotes autophagy and the expression of eNOS, resulting in NO production and the inhibition of O generation, and ultimately increasing in EC migration and tube formation. dHDL showed opposite effects compared to nHDL and ultimately inhibited EC migration and tube formation. We found that autophagy-related protein 5 (ATG5) was a direct target of miR-181a-5p. ATG5 silencing or miR-181a-5p mimic inhibited nHDL-induced autophagy, eNOS expression, NO production, EC migration, tube formation, and enhanced O generation, whereas overexpression of ATG5 or miR-181a-5p inhibitor reversed the above effects of dHDL. ATG5 expression and angiogenesis were decreased in the ischemic lower limbs of hypercholesterolemic low-density lipoprotein receptor null (LDLr) mice when compared to C57BL/6 mice. ATG5 overexpression improved angiogenesis in ischemic hypercholesterolemic LDLr mice. Taken together, nHDL was able to stimulate autophagy by suppressing miR-181a-5p, subsequently increasing eNOS expression, which generated NO and promoted angiogenesis. In contrast, dHDL inhibited angiogenesis, at least partially, by increasing miR-181a-5p expression, which decreased autophagy and eNOS expression, resulting in a decrease in NO production and an increase in O generation. Our findings reveal a novel mechanism by which HDL affects angiogenesis by regulating autophagy and provide a therapeutic target for dHDL-impaired angiogenesis.
我们之前的研究表明，正常的高密度脂蛋白（nHDL）可以促进血管生成，而冠心病患者的 HDL（dHDL）则功能失调，会损害血管生成。自噬在血管生成中起着关键作用，而 HDL 可以调节自噬。然而，nHDL 和 dHDL 是否通过影响自噬来调节血管生成尚不清楚。用 nHDL 和 dHDL 处理内皮细胞（EC），有或没有自噬抑制剂。评估自噬、内皮型一氧化氮合酶（eNOS）表达、miRNA 表达、一氧化氮（NO）产生、超氧阴离子（O）生成、EC 迁移和管形成。nHDL 抑制 miR-181a-5p 的表达，促进自噬和 eNOS 的表达，导致 NO 产生和 O 生成的抑制，最终增加 EC 迁移和管形成。dHDL 与 nHDL 表现出相反的作用，最终抑制 EC 迁移和管形成。我们发现自噬相关蛋白 5（ATG5）是 miR-181a-5p 的直接靶标。ATG5 沉默或 miR-181a-5p 模拟抑制 nHDL 诱导的自噬、eNOS 表达、NO 产生、EC 迁移、管形成和增强 O 生成，而过表达 ATG5 或 miR-181a-5p 抑制剂则逆转了 dHDL 的上述作用。与 C57BL/6 小鼠相比，高脂血症低密度脂蛋白受体缺失（LDLr）小鼠缺血下肢的 ATG5 表达和血管生成减少。ATG5 过表达改善了缺血性高脂血症 LDLr 小鼠的血管生成。总之，nHDL 通过抑制 miR-181a-5p 刺激自噬，随后增加 eNOS 表达，产生 NO 并促进血管生成。相反，dHDL 通过增加 miR-181a-5p 的表达抑制血管生成，至少部分地，这降低了自噬和 eNOS 的表达，导致 NO 生成减少和 O 生成增加。我们的研究结果揭示了 HDL 通过调节自噬影响血管生成的新机制，并为 dHDL 损害的血管生成提供了治疗靶点。
