MicroRNA-135a-5p Promotes the Functional Recovery of Spinal Cord Injury by Targeting SP1 and ROCK

• Published in: Molecular therapy. Nucleic acids Vol. 22; pp. 1063 - 1077
• Main Authors: Wang, Nanxiang, Yang, Yang, Pang, Mao, Du, Cong, Chen, Yuyong, Li, Simin, Tian, Zhenming, Feng, Feng, Wang, Yang, Chen, Zhenxiang, Liu, Bin, Rong, Limin
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 04.12.2020; American Society of Gene & Cell Therapy; Elsevier
• Subjects: microRNA-135a-5p; Original; PC12 cell; ROCK; SP1; spinal cord injury; spinal cord injury; PC12 cell; ROCK; microRNA-135a-5p; SP1
• ISSN: 2162-2531; 2162-2531
• DOI: 10.1016/j.omtn.2020.08.035

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 H2O2-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. [Display omitted] Wang et al. demonstrate that upregulating miR-135a-5p can promote axon outgrowth by modulating the ROCK-AKT/GSK3β pathway and suppress neural apoptosis by inhibiting the SP1-Bcl-2/Bax/caspase-3 pathway. These findings provide two novel signaling axes (miR-135a-5p-ROCK-AKT/GSK3β and miR-135a-5p-SP1-Bcl-2/Bax/caspase-3) that may be potential therapeutic targets in promoting functional recovery following spinal cord injury.