Department of Cardiology, Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin 300121, P.R. China.
School of Graduate Studies, Tianjin Medical University, Tianjin 300070, P.R. China.
Int J Mol Med. 2019 Nov;44(5):1899-1907. doi: 10.3892/ijmm.2019.4330. Epub 2019 Sep 4.
Patients with ischemic hearts who have refused coronary vascular reconstruction may exhibit dynamic myocardial remodeling and cardiac dysfunction. In the present study, the role of miRNA‑1 and its association with the ubiquitin‑proteasome system (UPS) in regulating myocardial remodeling was investigated. A myocardial infarction (MI) model was constructed and the hearts were treated with miRNA‑1 antagomir, miRNA‑1 lentiviral vectors and the UPS proteasome blocker bortezomib. The expression levels of miRNA‑1 were evaluated using reverse transcription PCR and the abundance of the ubiquitin‑proteasome protein and caspase‑3 were evaluated via western blot analysis. Furthermore, the collagen volume fraction was calculated using Masson's trichrome staining, and the apoptosis index was detected via terminal deoxynucleotidyl transferase dUTP‑biotin nick end labeling staining. Transforming growth factor (TGF)‑β expression was assessed via immunohistochemical staining. Echocardiographic characteristics and myocardial infarct size were analyzed. miRNA‑1 expression levels were found to be increased following MI. miRNA‑1 antagomir administration clearly inhibited miRNA‑1 expression, whereas the miRNA‑1 lentiviral vector exerted the opposite effect. The levels of 19s proteasome, 20S proteasome and ubiquitin ligase E3 were decreased in the miRNA‑1 antagomir group, but were significantly increased in the miRNA‑1 lentiviral group; however, only 20S proteasome expression was decreased in the bortezomib group. Collagen hyperplasia and TGF‑β expression were decreased in both the miRNA‑1 antagomir and bortezomib groups, although the effects of the miRNA‑1 antagomir were more noticeable. The miRNA‑1 antagomir and the UPS proteasome blocker both alleviated the ultrastructural impairments, demonstrated by a decreased left ventricular (LV) end‑diastolic diameter and LV mass, but the miRNA‑1 antagomir was also able to increase LV ejection fraction and LV fractional shortening. miRNA‑1 regulated UPS‑associated mRNA expression and affected the majority of the UPS components in the myocardium, thereby leading to increased myocardial cell apoptosis, myocardial fibrosis and remodeling. The miRNA‑1 antagomir exerted a more prominent cardioprotective effect compared with the UPS proteasome blocker bortezomib.
患有缺血性心脏病并拒绝进行冠状血管重建的患者可能会出现心肌动态重构和心功能障碍。在本研究中，研究了 miRNA-1 及其与泛素-蛋白酶体系统（UPS）在调节心肌重构中的作用。构建心肌梗死（MI）模型，并使用 miRNA-1 拮抗剂、miRNA-1 慢病毒载体和 UPS 蛋白酶体抑制剂硼替佐米进行心脏治疗。采用逆转录 PCR 评估 miRNA-1 的表达水平，采用 Western blot 分析评估泛素-蛋白酶体蛋白和半胱天冬酶-3 的丰度。此外，通过 Masson 三色染色计算胶原体积分数，并通过末端脱氧核苷酸转移酶 dUTP-生物素缺口末端标记染色检测细胞凋亡指数。通过免疫组织化学染色评估转化生长因子（TGF）-β的表达。分析超声心动图特征和心肌梗死面积。结果发现，MI 后 miRNA-1 的表达水平增加。miRNA-1 拮抗剂给药可明显抑制 miRNA-1 的表达，而 miRNA-1 慢病毒载体则产生相反的效果。miRNA-1 拮抗剂组 19s 蛋白酶体、20S 蛋白酶体和泛素连接酶 E3 的水平降低，但 miRNA-1 慢病毒组显著增加；然而，只有硼替佐米组的 20S 蛋白酶体表达降低。miRNA-1 拮抗剂和硼替佐米组的胶原增生和 TGF-β表达均减少，但 miRNA-1 拮抗剂的作用更为明显。miRNA-1 拮抗剂和 UPS 蛋白酶体抑制剂均可减轻超微结构损伤，表现为左心室（LV）舒张末期直径和 LV 质量减小，但 miRNA-1 拮抗剂还可以增加 LV 射血分数和 LV 缩短分数。miRNA-1 调节 UPS 相关 mRNA 表达，并影响心肌中的大多数 UPS 成分，从而导致心肌细胞凋亡、心肌纤维化和重构增加。与 UPS 蛋白酶体抑制剂硼替佐米相比，miRNA-1 拮抗剂表现出更显著的心脏保护作用。
