Department of Cardiology, The First Affiliated Hospital of ZhengzhouUniversity, Zhengzhou 450052, Henan, China; Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, Henan, China.
Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan, China.
Int J Cardiol. 2021 Sep 1;338:14-23. doi: 10.1016/j.ijcard.2021.05.053. Epub 2021 Jun 2.
As a dominant cardiovascular disease, myocardial infarction (MI) causes a considerable mortality globally. KCNQ1 overlapping transcript 1 (KCNQ1OT1) was reported to be overexpressed in MI patients. However, the detailed mechanisms remain unclear.
We analyzed the expression of KCNQ1OT1 in the serum of MI patients, and built ischemia/reperfusion (I/R) mouse and H/R-induced cell model. TTC staining was used to evaluate infarct size in mice. TUNEL was employed to assess cell apoptosis. QRT-PCR was performed to detect the expression of KCNQ1OT1 and miR-26a-5p. The formation of autophagosomes in cells was detected by immunofluorescence. Caspase3 activity was detected by the Caspase-3 Assay Kit. Autophagy and apoptosis-related proteins were assessed by western blotting. Luciferase reporter assay was used to assess the binding relationship of KCNQ1OT1 and miR-26a-5p and miR-20a-5p/ATG12.
KCNQ1OT1 was up-regulated while miR-26a-5p was decreased in MI patients, I/R mouse and H/R-induced cell model. KCNQ1OT1 knockdown inhibited cell autophagy and protected cardiomyocytes from apoptosis by up-regulating miR-26a-5p. Either KCNQ1OT1 knockdown or miR-26a-5p mimics caused inhibition of autophagy related 12 homolog (ATG12), which was the direct target of miR-26a-5p. In vivo, KCNQ1OT1 promoted cardiomyocytes apoptosis via miR-26a-5p/ATG12 pathway.
KCNQ1OT1/miR-26a-5p/ATG12 axis regulated cardiomyocyte autophagy and apoptosis, both in vivo and in vitro. These data supported that KCNQ1OT1 inhibition might be a promising therapeutic option for protection after MI.
心肌梗死（MI）作为一种主要的心血管疾病，在全球范围内导致了相当高的死亡率。已有报道称，KCNQ1 重叠转录本 1（KCNQ1OT1）在 MI 患者中过表达。然而，其详细的机制仍不清楚。
我们分析了 MI 患者血清中的 KCNQ1OT1 表达，并构建了缺血/再灌注（I/R）小鼠和 H/R 诱导的细胞模型。TTC 染色用于评估小鼠的梗死面积。TUNEL 用于评估细胞凋亡。QRT-PCR 用于检测 KCNQ1OT1 和 miR-26a-5p 的表达。通过免疫荧光检测细胞自噬体的形成。通过 Caspase-3 测定试剂盒检测 caspase3 活性。通过 Western blot 检测自噬和凋亡相关蛋白。通过荧光素酶报告实验评估 KCNQ1OT1 与 miR-26a-5p 和 miR-20a-5p/ATG12 的结合关系。
在 MI 患者、I/R 小鼠和 H/R 诱导的细胞模型中，KCNQ1OT1 上调，而 miR-26a-5p 下调。KCNQ1OT1 敲低通过上调 miR-26a-5p 抑制细胞自噬并保护心肌细胞免于凋亡。KCNQ1OT1 敲低或 miR-26a-5p 模拟物均导致自噬相关 12 同源物（ATG12）的抑制，而 ATG12 是 miR-26a-5p 的直接靶标。在体内，KCNQ1OT1 通过 miR-26a-5p/ATG12 通路促进心肌细胞凋亡。
KCNQ1OT1/miR-26a-5p/ATG12 轴在体内和体外调节心肌细胞自噬和凋亡。这些数据支持抑制 KCNQ1OT1 可能是 MI 后保护的一种有前途的治疗选择。
