Department of Pharmacology, and Cardiac & Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China.
Acta Pharmacol Sin. 2021 Apr;42(4):550-559. doi: 10.1038/s41401-020-0440-4. Epub 2020 Jul 21.
The excessive proliferation and migration of smooth muscle cells (SMCs) play an important role in restenosis following percutaneous coronary interventions. MicroRNAs are able to target various genes and involved in the regulation of diverse cellular processes including cell growth and proliferation. In this study we investigated whether and how MicroRNAs regulated vascular SMC proliferation and vascular remodeling following carotid artery injury in mice. We showed that carotid artery injury-induced neointimal formation was remarkably ameliorated in microRNA (miR)-302 heterozygous mice and SMC-specific miR-302 knockout mice. In contrast, delivery of miR-302a adenovirus to the injured carotid artery enhanced neointimal formation. Upregulation of miR-302a enhanced the proliferation and migration of mouse aorta SMC (MASMC) in vitro by promoting cell cycle transition, whereas miR-302a inhibition caused the opposite results. Moreover, miR-302a promoted Akt activation by corporately decreasing Akt expression and increasing Akt phosphorylation in MASMCs. Application of the Akt inhibitor GSK690693 (5 μmol/L) counteracted the functions of miR-302a in promoting MASMC proliferation and migration. We further revealed that miR-302a directly targeted at the 3' untranslated region of PH domain and leucine rich repeat protein phosphatase 2 (PHLPP2) and negatively regulated PHLPP2 expression. Restoration of PHLPP2 abrogated the effects of miR-302a on Akt activation and MASMC motility. Furthermore, knockdown of PHLPP2 largely abolished the inhibition of neointimal formation that was observed in miR-302 heterozygous mice. Our data demonstrate that miR-302a exacerbates SMC proliferation and restenosis through increasing Akt signaling by targeting PHLPP2.
平滑肌细胞（SMC）的过度增殖和迁移在经皮冠状动脉介入治疗后的再狭窄中起着重要作用。microRNAs 能够靶向各种基因，并参与调节包括细胞生长和增殖在内的多种细胞过程。在这项研究中，我们研究了 microRNAs 是否以及如何调节小鼠颈动脉损伤后的血管 SMC 增殖和血管重塑。我们发现，miR-302 杂合子小鼠和 SMC 特异性 miR-302 敲除小鼠的颈动脉损伤诱导的新生内膜形成明显改善。相比之下，向损伤的颈动脉递送 miR-302a 腺病毒增强了新生内膜的形成。miR-302a 的上调通过促进细胞周期转变增强了体外培养的小鼠主动脉平滑肌细胞（MASMC）的增殖和迁移，而 miR-302a 的抑制则产生了相反的结果。此外，miR-302a 通过共同降低 MASMC 中的 Akt 表达和增加 Akt 磷酸化来促进 Akt 激活。应用 Akt 抑制剂 GSK690693（5μmol/L）可抵消 miR-302a 促进 MASMC 增殖和迁移的作用。我们进一步揭示了 miR-302a 直接靶向 PH 结构域和富含亮氨酸重复蛋白磷酸酶 2（PHLPP2）的 3'非翻译区，并负调控 PHLPP2 的表达。PHLPP2 的恢复消除了 miR-302a 对 Akt 激活和 MASMC 迁移的影响。此外，PHLPP2 的敲低大大消除了在 miR-302 杂合子小鼠中观察到的新生内膜形成的抑制作用。我们的数据表明，miR-302a 通过靶向 PHLPP2 增加 Akt 信号来加剧 SMC 增殖和再狭窄。
