Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, 250021, Jinan, Shandong, China.
Department of Nephrology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, 250021, Jinan, Shandong, China.
Cell Death Dis. 2022 Jul 29;13(7):661. doi: 10.1038/s41419-022-05068-1.
Endothelial dysfunction is common in patients with chronic kidney disease (CKD), but the mechanism is unknown. In this study, we found that the circulating ANRIL level was increased and correlated with vascular endothelial dysfunction in patients with CKD, also negatively correlated with plasma brain-derived neurotrophic factor (BDNF) concentration. We constructed the ANRIL knockout mice model, and found that ANRIL deficiency reversed the abnormal expression of BDNF, along with endothelial nitric oxide synthase (eNOS), vascular adhesion molecule 1 (VCAM-1) and Von Willebrand factor (vWF). Meanwhile, mitochondrial dynamics-related proteins, Dynamin-related protein 1 (Drp1) and mitofusins (Mfn2) level were also recovered. In addition, in vitro, serum derived from CKD patients and uremia toxins induced abnormal expression of ANRIL. By making use of the gain- and loss-of-function approaches, we observed that ANRIL mediated endothelial dysfunction through BDNF downregulation. To explore the specific mechanism, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) were used to explore the binding of ANRIL to histone methyltransferase Enhancer of zeste homolog 2 (EZH2). Further experiments found increased EZH2 and histone H3 lysine 27 trimethylation (H3K27me3) levels at the BDNF promoter region. Collectively, we demonstrated that ANRIL mediate BDNF transcriptional suppression through recruitment of EZH2 to the BDNF promoter region, then regulated the proteins expression related to endothelial function and mitochondrial dynamics. This study provides new insights for the study of endothelial dysfunction in CKD.
内皮功能障碍在慢性肾脏病（CKD）患者中很常见，但机制尚不清楚。在这项研究中，我们发现循环 ANRIL 水平升高，并与 CKD 患者的血管内皮功能障碍相关，也与血浆脑源性神经营养因子（BDNF）浓度呈负相关。我们构建了 ANRIL 敲除小鼠模型，发现 ANRIL 缺乏可逆转 BDNF、内皮型一氧化氮合酶（eNOS）、血管细胞黏附分子 1（VCAM-1）和血管性血友病因子（vWF）的异常表达。同时，线粒体动力学相关蛋白，如动力相关蛋白 1（Drp1）和融合蛋白（Mfn2）的水平也得到了恢复。此外，在体外，CKD 患者的血清和尿毒症毒素诱导 ANRIL 的异常表达。通过使用增益和缺失功能的方法，我们观察到 ANRIL 通过下调 BDNF 引起内皮功能障碍。为了探索具体的机制，我们利用 RNA 下拉和 RNA 结合蛋白免疫沉淀（RIP）实验来探索 ANRIL 与组蛋白甲基转移酶 Enhancer of zeste 同源物 2（EZH2）的结合。进一步的实验发现，BDNF 启动子区域的 EZH2 和组蛋白 H3 赖氨酸 27 三甲基化（H3K27me3）水平升高。总之，我们证明了 ANRIL 通过招募 EZH2 到 BDNF 启动子区域来介导 BDNF 的转录抑制，从而调节与内皮功能和线粒体动力学相关的蛋白质表达。这项研究为研究 CKD 中的内皮功能障碍提供了新的见解。
