Department of Cardiology, Zhongda Hospital, Southeast University, Dingjiaqiao Road, Nanjing, 210009, China.
Mol Biol Rep. 2023 Dec 28;51(1):32. doi: 10.1007/s11033-023-08932-1.
Current studies have suggested that miRNA is beneficial in inhibiting myocardial remodeling after myocardial infarction (AMI), however, its underlying mechanism is unclear.
We aimed to investigate whether miR-150 can inhibit myocardial remodeling after myocardial infarction and whether this process is regulated by the miR-150/TET3 pathway.
On the first day, C57BL/6 AMI mice(n = 15) were administrated with miR-150, and another 15 AMI mice were administrated with the same volume of control Agomir. Left ventricular ejection fraction (LVEF%) and myocardial remodeling were compared after one week; TET3 (ten-eleven translocation 3) and VEGF-α (vascular endothelial growth factor-α) were also determined in the infracted heart simultaneously. The neovascularization in the infarcted area at day 21 was compared through CD31 using fluorescence microscopy; Activated monocytes stimulated with LPS were transfected with miR-150. Laser scanning confocal microscopy was used to detect the intracytoplasmic imaging of miR-150 in Ly6C monocytes. Expression of the miR-150 in the monocytes was measured using Q-PCR. After 48 h, the proportion of Ly6C monocytes was determined using flow cytometry. Expression of TET3 in Ly6C monocytes was measured using Q-PCR and Western blot. After the downregulation of TET3 specifically, the levels of Ly6C monocytes were further determined.
We first observed an increased trend of mice survival rate in the miR-150 injection group, but it didn't reach a statistical difference (66.7% vs. 40.0%, p = 0.272). However, AMI mice administrated with miR-150 displayed better LVEF% (51.78%±2.90% vs. 40.28%±4.20%, p<0.001) and decreased infarct size% (25.47 ± 7.75 vs. 50.39 ± 16.91, p = 0.002). After miR-150 was transfected into monocytes, the percentage of Ly6C monocytes increased significantly after 48 h (48.5%±10.1% vs. 42.5%±8.3%, p < 0.001). Finally, Western blot analysis (0.56 ± 0.10/β-actin vs. 0.99 ± 0.12/β-actin, p < 0.001) and real-time PCR (1.09 ± 0.09/GAPDH vs. 2.53 ± 0.15/GAPDH, p < 0.001, p < 0.001) both confirmed decreased expression of TET3 in monocytes after transfection with miR-150. After the downregulation of TET3 specifically, Ly6C monocytes showed a significant increase (16.73%±6.45% vs. 6.94%±2.99%, p<0.001, p < 0.001).
miR-150 alleviated myocardial remodeling after AMI. Possible mechanisms are ascribed to the regulating of TET3 and VEGF-α in inflammatory monocytes.
目前的研究表明，miRNA 有益于抑制心肌梗死后的心肌重构，但其中的具体机制仍不清楚。
本研究旨在探讨 miR-150 是否能抑制心肌梗死后的心肌重构，以及这一过程是否受到 miR-150/TET3 通路的调控。
在第 1 天，15 只 C57BL/6 AMI 小鼠给予 miR-150，另外 15 只 AMI 小鼠给予相同体积的对照 Agomir。1 周后比较左心室射血分数（LVEF%）和心肌重构；同时在梗死心脏中检测 TET3（ten-eleven translocation 3）和 VEGF-α（血管内皮生长因子-α）。通过荧光显微镜观察 CD31 比较梗死区第 21 天的新生血管；用 LPS 刺激激活的单核细胞转染 miR-150。用激光共聚焦显微镜检测 Ly6C 单核细胞胞质内 miR-150 的成像。用 Q-PCR 检测单核细胞中 miR-150 的表达。48 小时后，用流式细胞术检测 Ly6C 单核细胞的比例。用 Q-PCR 和 Western blot 检测 Ly6C 单核细胞中 TET3 的表达。在特异性下调 TET3 后，进一步检测 Ly6C 单核细胞的水平。
我们首先观察到 miR-150 注射组小鼠的存活率有增加趋势，但未达到统计学差异（66.7% vs. 40.0%，p=0.272）。然而，给予 miR-150 的 AMI 小鼠的 LVEF%（51.78%±2.90% vs. 40.28%±4.20%，p<0.001）更高，梗死面积百分比（25.47 ± 7.75 vs. 50.39 ± 16.91，p=0.002）更低。miR-150 转染单核细胞后，48 小时后 Ly6C 单核细胞的比例显著增加（48.5%±10.1% vs. 42.5%±8.3%，p<0.001）。最后，Western blot 分析（0.56 ± 0.10/β-actin vs. 0.99 ± 0.12/β-actin，p<0.001）和实时 PCR（1.09 ± 0.09/GAPDH vs. 2.53 ± 0.15/GAPDH，p<0.001，p<0.001）均证实 miR-150 转染后单核细胞中 TET3 的表达降低。特异性下调 TET3 后，Ly6C 单核细胞显著增加（16.73%±6.45% vs. 6.94%±2.99%，p<0.001，p<0.001）。
miR-150 减轻了 AMI 后的心肌重构。可能的机制归因于炎症单核细胞中 TET3 和 VEGF-α 的调节。
