Wang Nanxiang, Yang Yang, Pang Mao, Du Cong, Chen Yuyong, Li Simin, Tian Zhenming, Feng Feng, Wang Yang, Chen Zhenxiang, Liu Bin, Rong Limin
Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, No. 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China.
Cell-Gene Therapy Translational Medicine Research Center, The Third Affiliated Hospital of Sun Yat-Sen University, No. 600 Tianhe Road, Tianhe District, Guangzhou, Guangdong Province, People's Republic of China.
Mol Ther Nucleic Acids. 2020 Sep 3;22:1063-1077. doi: 10.1016/j.omtn.2020.08.035. eCollection 2020 Dec 4.
Emerging evidence indicates that microRNAs play a pivotal role in neural remodeling after spinal cord injury (SCI). This study aimed to investigate the mechanisms of miR-135a-5p in regulating the functional recovery of SCI by impacting its target genes and downstream signaling. The gene transfection assay and luciferase reporter assay confirmed the target relationship between miR-135a-5p and its target genes (specificity protein 1 [SP1] and Rho-associated kinase [ROCK]1/2). By establishing the HO-induced injury model, miR-135a-5p transfection was found to inhibit the apoptosis of PC12 cells by downregulating the SP1 gene, which subsequently induced downregulation of pro-apoptotic proteins (Bax, cleaved caspase-3) and upregulation of anti-apoptotic protein Bcl-2. By measuring the neurite lengths of PC12 cells, miR-135a-5p transfection was found to promote axon outgrowth by downregulating the ROCK1/2 gene, which subsequently caused upregulation of phosphate protein kinase B (AKT) and phosphate glycogen synthase kinase 3β (GSK3β). Use of the rat SCI models showed that miR-135a-5p could increase the Basso, Beattie, and Bresnahan (BBB) scores, indicating neurological function recovery. In conclusion, the miR-135a-5p-SP1-Bax/Bcl-2/caspase-3 and miR-135a-5p-ROCK-AKT/GSK3β axes are involved in functional recovery of SCI by regulating neural apoptosis and axon regeneration, respectively, and thus can be promising effective therapeutic strategies in SCI.
新出现的证据表明，微小RNA在脊髓损伤（SCI）后的神经重塑中起关键作用。本研究旨在通过影响其靶基因和下游信号来探究miR-135a-5p调节SCI功能恢复的机制。基因转染实验和荧光素酶报告基因检测证实了miR-135a-5p与其靶基因（特异性蛋白1 [SP1]和Rho相关激酶[ROCK]1/2）之间的靶向关系。通过建立过氧化氢诱导的损伤模型，发现miR-135a-5p转染可通过下调SP1基因抑制PC12细胞凋亡，随后诱导促凋亡蛋白（Bax、裂解的半胱天冬酶-3）下调和抗凋亡蛋白Bcl-2上调。通过测量PC12细胞的神经突长度，发现miR-135a-5p转染可通过下调ROCK1/2基因促进轴突生长，随后导致磷酸化蛋白激酶B（AKT）和磷酸化糖原合酶激酶3β（GSK3β）上调。使用大鼠SCI模型表明，miR-135a-5p可提高Basso、Beattie和Bresnahan（BBB）评分，表明神经功能恢复。总之，miR-135a-5p-SP1-Bax/Bcl-2/半胱天冬酶-3和miR-135a-5p-ROCK-AKT/GSK3β轴分别通过调节神经细胞凋亡和轴突再生参与SCI的功能恢复，因此有望成为SCI有效的治疗策略。
