Department of Spine Surgery, Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, No. 555, Youyi East Road, Beilin District, Xi'an, 710054, China.
Mol Neurobiol. 2022 Aug;59(8):4854-4868. doi: 10.1007/s12035-022-02896-2. Epub 2022 May 31.
LncRNA myocardial infarction-associated transcript (MIAT) alleviates acute spinal cord injury (ASCI)-induced neuronal cell apoptosis, but the specific mechanism of it involved in regulating SCI progression needs further exploration. Here, a SCI rat model was established, followed by administration with adenovirus-mediated MIAT overexpression vector (Ad-MIAT) alone or together with Ad-RBFOX2 (RNA binding fox-1 homolog 2). The data indicated that MIAT overexpression promoted motor function recovery, improved morphology of injured tissues, and restrained neuron loss and cell apoptosis in SCI rats. Then, PC-12 cells were treated with HO to induce cell injury. And highly expressed MIAT suppressed HO-caused decrease in cell viability and increase in cell apoptosis. MIAT stabilized RBFOX2 protein expression by binding to RBFOX2, thereby promoting RBFOX2-induced upregulation of anti-apoptotic MCL-1L (myeloid cell leukemia sequence 1) and reduction of pro-apoptotic MCL-1S. And silencing RBFOX2 in vitro blocked the inhibitory effect of MIAT on cell apoptosis. Moreover, MCL-1-specific steric-blocking oligonucleotides (SBOs) were used to transfer the MCL-1 pre-mRNA splicing pattern from MCL-1L to MCL-1S. SBOs reversed the protection effect of RBFOX2 overexpression on HO-induced cell injury. Furthermore, overexpression of MCL-1L instead of MCL-1S facilitated autophagy activation in HO-stimulated cells. Interestingly, co-overexpression of MIAT and RBFOX2 had a better promoting effect on SCI recovery. In conclusion, MIAT mitigated SCI by promoting RBFOX2-mediated alternative splicing of MCL-1. Our findings might provide a promising therapeutic target for SCI.
长链非编码 RNA 心肌梗塞相关转录物（MIAT）减轻急性脊髓损伤（ASCI）诱导的神经元细胞凋亡，但它调节 SCI 进展的具体机制需要进一步探索。在这里，建立了 SCI 大鼠模型，然后单独或与 RNA 结合 Fox-1 同源物 2（RBFOX2）的腺病毒介导的 MIAT 过表达载体（Ad-MIAT）一起给药。数据表明，MIAT 过表达促进运动功能恢复，改善损伤组织形态，抑制 SCI 大鼠神经元丢失和细胞凋亡。然后，用 HO 处理 PC-12 细胞诱导细胞损伤。并且高表达的 MIAT 抑制了 HO 引起的细胞活力下降和细胞凋亡增加。MIAT 通过与 RBFOX2 结合稳定 RBFOX2 蛋白表达，从而促进 RBFOX2 诱导的抗凋亡 MCL-1L（髓样细胞白血病序列 1）上调和促凋亡 MCL-1S 下调。并且体外沉默 RBFOX2 阻断了 MIAT 对细胞凋亡的抑制作用。此外，使用 MCL-1 特异性立体阻碍寡核苷酸（SBOs）将 MCL-1 前体 mRNA 的剪接模式从 MCL-1L 转移到 MCL-1S。SBOs 逆转了 RBFOX2 过表达对 HO 诱导的细胞损伤的保护作用。此外，MCL-1L 而不是 MCL-1S 的过表达促进了 HO 刺激细胞中的自噬激活。有趣的是，MIAT 和 RBFOX2 的共过表达对 SCI 恢复有更好的促进作用。总之，MIAT 通过促进 RBFOX2 介导的 MCL-1 的可变剪接减轻 SCI。我们的研究结果可能为 SCI 提供有前途的治疗靶点。
