Department of Cardiology, The First Affiliated Hospital of Soochow University.
Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University.
Chem Pharm Bull (Tokyo). 2021;69(6):529-536. doi: 10.1248/cpb.c20-01003.
Emerging evidence highlights the importance of microRNAs (miRNAs) as functional regulators in cardiovascular disease. This study aimed to investigate the functional significance of miR-135a in the regulation of cardiac injury after isoprenaline (ISO) stimulation and the underlying mechanisms of its effects. Murine models with cardiac-specific overexpression of miR-135a were constructed with an adeno-associated virus expression system. The cardiac injury model was induced by ISO injection (60 mg/kg per day for 14 d). In vitro, we used H9c2 cells to establish a cell injury model by ISO stimulation (10 µM). The results indicated that miR-135a was increased during days 0-6 of ISO injection and was then downregulated during days 8-14 of ISO injection. The expression of miR-135a was consistent with the in vivo findings. Moreover, mice with cardiac overexpression of miR-135a exhibited reduced cardiac fibrosis, lactate dehydrogenase levels, Troponin I, inflammatory response and apoptosis. Overexpression of miR-135a also ameliorated cardiac dysfunction induced by ISO. MiR-135 overexpression in H9c2 cells increased cell viability and decreased cell apoptosis and inflammation in response to ISO. Conversely, miR-135 silencing in H9c2 cells decreased cell viability and increased cell apoptosis and inflammation in response to ISO. Mechanistically, we found that miR-135a negatively regulated toll-like receptor 4 (TLR4), which was confirmed by luciferase assay. Furthermore, the TLR4 inhibitor eritoran abolished the adverse effect of miR-135 silencing. Overall, miR-135a promotes ISO-induced cardiac injury by inhibiting the TLR4 pathway. MiR-135a may be a therapeutic agent for cardiac injury.
新出现的证据强调了 microRNAs（miRNAs）作为心血管疾病功能调节剂的重要性。本研究旨在探讨 miR-135a 在异丙肾上腺素（ISO）刺激后心脏损伤调节中的功能意义及其作用机制。使用腺相关病毒表达系统构建了心脏特异性过表达 miR-135a 的小鼠模型。通过 ISO 注射（每天 60mg/kg，持续 14 天）诱导心脏损伤模型。在体外，我们使用 H9c2 细胞通过 ISO 刺激（10μM）建立细胞损伤模型。结果表明，在 ISO 注射的第 0-6 天，miR-135a 增加，然后在 ISO 注射的第 8-14 天下调。miR-135a 的表达与体内发现一致。此外，心脏过表达 miR-135a 的小鼠表现出减少的心脏纤维化、乳酸脱氢酶水平、肌钙蛋白 I、炎症反应和细胞凋亡。ISO 诱导的心脏功能障碍也得到改善。在 H9c2 细胞中过表达 miR-135a 增加了细胞活力，降低了 ISO 诱导的细胞凋亡和炎症。相反，在 H9c2 细胞中沉默 miR-135a 降低了细胞活力，增加了 ISO 诱导的细胞凋亡和炎症。在机制上，我们发现 miR-135a 通过负调控 Toll 样受体 4（TLR4），这通过荧光素酶测定得到证实。此外，TLR4 抑制剂 eritoran 消除了 miR-135 沉默的不良影响。总之，miR-135a 通过抑制 TLR4 通路促进 ISO 诱导的心脏损伤。miR-135a 可能是心脏损伤的治疗剂。
