Induction of microRNA-1 by myocardin in smooth muscle cells inhibits cell proliferation.
Induction of microRNA-1 by myocardin in smooth muscle cells inhibits cell proliferation.
复制标题
DOI：
10.1161/atvbaha.110.218149
复制
发表时间：
2011-02
期刊：
影响因子：
--
通讯作者：
Zheng XL
中科院分区：
文献类型：
--
作者：
Chen J;Yin H;Jiang Y;Radhakrishnan SK;Huang ZP;Li J;Shi Z;Kilsdonk EP;Gui Y;Wang DZ;Zheng XL
心肌素是一种心脏和平滑肌特异性转录因子，可有效激活下游靶基因的表达。此前，我们证明心肌素的过度表达会抑制平滑肌细胞（SMC）的增殖。最近，据报道，myocardin 可诱导心肌细胞中 microRNA-1 (miR-1) 的表达。在本研究中，我们研究心肌素是否通过诱导 miR-1 表达来介导其对 SMC 增殖的抑制作用。使用在人血管 SMC 中表达心肌素的 T-REx 诱导系统，我们发现心肌素的过度表达导致 miR-1 表达显着诱导并抑制 SMC 增殖，而 miR-1 抑制剂可逆转这一现象。一致的是，将 miR-1 引入 SMC 会显着抑制其增殖。我们分离了纺锤形和上皮样人类 SMC，并证明纺锤形 SMC 分化程度更高，增殖能力更差。相应地，纺锤形 SMC 的心肌素和 miR-1 表达水平显着高于上皮样 SMC。我们确定 Pim-1（一种丝氨酸/苏氨酸激酶）作为 SMC 中 miR-1 的靶基因。 Western blot 和荧光素酶报告基因检测进一步证实 miR-1 直接靶向 Pim-1。此外，小鼠颈动脉的新生内膜损伤显示心肌素和 miR-1 下调，而 Pim-1 上调。我们的数据表明 miR-1 参与心肌素依赖性 SMC 增殖抑制。
Myocardin is a cardiac- and smooth muscle-specific transcription factor that potently activates the expression of downstream target genes. Previously, we demonstrated that overexpression of myocardin inhibited the proliferation of smooth muscle cells (SMCs). Recently, myocardin was reported to induce the expression of microRNA-1 (miR-1) in cardiomyocytes. In this study, we investigate whether myocardin induces miR-1 expression to mediate its inhibitory effects on SMC proliferation. Using T-REx inducible system expressing myocardin in human vascular SMCs, we found that overexpression of myocardin resulted in significant induction of miR-1 expression and inhibition of SMC proliferation, which was reversed by miR-1 inhibitors. Consistently, introduction of miR-1 into SMCs dramatically inhibited their proliferation. We have isolated spindle-shaped and epithelioid human SMCs and demonstrated that spindle-shaped SMCs were more differentiated and less proliferative. Correspondingly, spindle-shaped SMCs had significantly higher expression levels of both myocardin and miR-1 than epithelioid SMCs. We identified Pim-1, a serine/threonine kinase, as a target gene for miR-1 in SMCs. Western blot and luciferase reporter assays further confirmed that miR-1 targets Pim-1 directly. Furthermore, neointimal lesions of mouse carotid arteries display down-regulation of myocardin and miR-1 with up-regulation of Pim-1. Our data demonstrate that miR-1 participates myocardin-dependent SMC proliferation inhibition.