Department of Pulmonary and Critical Care Medicine, The First Hospital of Lanzhou University, Lanzhou 730000, China.
The First School of Clinical Medicine, Lanzhou University, Lanzhou 730000, China.
Oxid Med Cell Longev. 2021 Aug 30;2021:9360339. doi: 10.1155/2021/9360339. eCollection 2021.
Although chronic intermittent hypoxia- (IH-) induced myocardial apoptosis is an established pathophysiological process resulting in a poor prognosis for patients with obstructive sleep apnea syndrome, its underlying mechanism remains unclear. This study is aimed at exploring the role of makorin ring finger protein 1 (MKRN1) in IH-induced myocardial apoptosis and elucidating its molecular activity. First, the GSE2271 dataset was downloaded from the Gene Expression Omnibus database to identify the differentially expressed genes. Then, an SD rat model of IH, together with rat cardiomyocyte H9C2 and human cardiomyocyte AC16 IH models, was constructed. TUNEL, Western blot, and immunohistochemistry assays were used to detect cell apoptosis. Dihydroethidium staining was conducted to analyze the concentration of reactive oxygen species. In addition, RT-qPCR, Western blot, and immunohistochemistry were performed to measure the expression levels of MKRN1 and p21. The direct interaction between MKRN1 and p21 was determined using coimmunoprecipitation and ubiquitination analysis. MKRN1 expression was found to be downregulated in IH rat myocardial tissues as well as in H9C2 and AC16 cells. Upregulated expression of MKRN1 in H9C2 and AC16 cells alleviated the IH-induced reactive oxygen species production and cell apoptosis. Mechanistically, MKRN1 promoted p21 protein ubiquitination and the proteasome pathway degradation to negatively regulate p21 expression. Thus, MKRN1 regulates p21 ubiquitination to prevent IH-induced myocardial apoptosis.
虽然慢性间歇性低氧诱导的心肌细胞凋亡是阻塞性睡眠呼吸暂停综合征患者预后不良的既定病理生理过程，但其潜在机制尚不清楚。本研究旨在探讨 makorin 环指蛋白 1 (MKRN1) 在 IH 诱导的心肌细胞凋亡中的作用，并阐明其分子活性。首先，从基因表达综合数据库中下载 GSE2271 数据集，以鉴定差异表达基因。然后，构建 IH 大鼠模型、大鼠心肌细胞 H9C2 和人心肌细胞 AC16 IH 模型。TUNEL、Western blot 和免疫组织化学检测细胞凋亡。二氢乙啶染色分析活性氧浓度。此外，进行 RT-qPCR、Western blot 和免疫组织化学检测 MKRN1 和 p21 的表达水平。通过共免疫沉淀和泛素化分析确定 MKRN1 和 p21 之间的直接相互作用。IH 大鼠心肌组织以及 H9C2 和 AC16 细胞中 MKRN1 的表达下调。H9C2 和 AC16 细胞中 MKRN1 的上调表达减轻了 IH 诱导的活性氧产生和细胞凋亡。在机制上，MKRN1 促进 p21 蛋白泛素化和蛋白酶体途径降解，从而负调控 p21 的表达。因此，MKRN1 通过调节 p21 的泛素化来防止 IH 诱导的心肌细胞凋亡。
