Li Zhijun, Yu Yifei, Kang Juanjuan, Zheng Yangyang, Xu Jinying, Xu Kan, Hou Kun, Hou Yi, Chi Guangfan
The Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, China.
Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China.
Front Cell Neurosci. 2020 Jul 2;14:144. doi: 10.3389/fncel.2020.00144. eCollection 2020.
Schwann cell (SC) transplantation is a promising approach for the treatment of spinal cord injury (SCI); however, SC grafts show a low migratory capacity within the astrocytic environment, which inevitably hampers their therapeutic efficacy. The purpose of this study was to explore mechanisms to modify the characteristics of SCs and astrocytes (ASs), as well as to adjust the SC-AS interface to break the SC-AS boundary, thus improving the benefits of SCI treatment. We observed that the expression levels of miR-124 in SCs and ASs were significantly lower than those in the normal spinal cord. Furthermore, overexpressing miR-124 in SCs (miR-124-SCs) significantly inhibited gene and protein expression levels of SC-specific markers, such as GFAP and Krox20. The expression of neurotrophic factors, and , was up-regulated in miR-124-SCs without affecting their proliferation. Further, the boundary assay showed an increased number of miR-124-SCs that had actively migrated and entered the astrocytic region to intermingle with ASs, compared with normal SCs. In addition, although Krox20 protein expression was down-regulated in miR-124-SCs, the luciferase assay showed that is not a direct target of miR-124. RNA sequencing of miR-124-SCs revealed seven upregulated and eleven downregulated genes involved in cell migration and motility. Based on KEGG pathway and KOG functional analyses, changes in these genes corresponded to the activation of Hippo, FoxO, and TGF-beta signaling pathways, cytokine-cytokine receptor interactions, and the cell cycle. Finally, co-culturing of miR-124-SCs and ASs in a transwell system revealed that GFAP and p-STAT3 protein expression in ASs was significantly reduced. Collectively, these results show that overexpression of miR-124 in SCs promotes SC-AS integration and may attenuate the capacity of ASs to form glial scars. Thus, this study provides novel insights into modifying SCs by overexpressing miR-124 to improve their therapeutic potential in SCI.
施万细胞（SC）移植是治疗脊髓损伤（SCI）的一种有前景的方法；然而，SC移植物在星形胶质细胞环境中的迁移能力较低，这不可避免地阻碍了它们的治疗效果。本研究的目的是探索改变SC和星形胶质细胞（AS）特性的机制，以及调整SC-AS界面以打破SC-AS边界，从而提高SCI治疗的益处。我们观察到SC和AS中miR-124的表达水平显著低于正常脊髓中的表达水平。此外，在SC中过表达miR-124（miR-124-SCs）显著抑制了SC特异性标志物（如GFAP和Krox20）的基因和蛋白表达水平。神经营养因子 和 的表达在miR-124-SCs中上调，且不影响其增殖。此外，边界试验表明，与正常SC相比，主动迁移并进入星形胶质细胞区域与AS混合的miR-124-SCs数量增加。此外，虽然miR-124-SCs中Krox20蛋白表达下调，但荧光素酶试验表明 不是miR-124的直接靶点。对miR-124-SCs的RNA测序揭示了7个上调和11个下调的基因，这些基因参与细胞迁移和运动。基于KEGG通路和KOG功能分析，这些基因的变化对应于Hippo、FoxO和TGF-β信号通路的激活、细胞因子-细胞因子受体相互作用以及细胞周期。最后，在transwell系统中共培养miR-124-SCs和AS，结果显示AS中GFAP和p-STAT3蛋白表达显著降低。总体而言，这些结果表明，SC中miR-124的过表达促进了SC-AS整合，并可能减弱AS形成胶质瘢痕的能力。因此，本研究为通过过表达miR-124修饰SC以提高其在SCI中的治疗潜力提供了新的见解。
