Department of Immunology, College of Basic Medical Sciences, Jilin University, Changchun 130021, PR China.
Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore, MD 21201, USA.
J Neuroimmunol. 2022 Oct 15;371:577929. doi: 10.1016/j.jneuroim.2022.577929. Epub 2022 Jul 22.
Microglia are involved in many neurodegenerative diseases and repairment of traumatic injury to the CNS. Activin A is a neurotrophic and neuroprotective factor that can regulate the activities of macrophages/microglia. However, the effects of activin A on the migration of microglia are still unclear. In this study, the role of activin A in regulation of the microglia migration was investigated with the murine microglial BV2 cell.
The levels of cytokines were detected by enzyme-linked immunosorbent assay (ELISA). The protein expression was examined by Western blotting. The adhesion of BV2 cells was assayed by real-time cell analysis (RTCA). The migration of BV2 cells was determined by transwell chamber and microfluidics device. Smad3 was overexpressed or knocked down in BV2 cells by transfection of Smad3 or Smad3 shRNA-expressing plasmids.
Activin A inhibited the release of nitric oxide (NO) and inflammatory cytokines of TNF-α and IL-6 and the expression of TNF-α and IL-6 mRNA by BV2 cells. In contrast, activin A promoted the production of TGF-β1. Activin A inhibited adhesion, promoted wound healing and migration which is related to the expression of N-cadherin and E-cadherin expression. Additionally, Smad3 overexpression in BV2 cells decreased the levels of TNF-α and IL-6, and promoted the wound healing, whereas Smad3 knockdown showed the opposite effects.
These findings revealed that activin A regulated the biological behavior of BV2 cells via Smad3 signaling, suggesting that activin A may serve as a potential treatment target for neuroinflammation and glia scar formation in nervous system.
小胶质细胞参与许多神经退行性疾病和中枢神经系统创伤的修复。激活素 A 是一种神经营养和神经保护因子，可调节巨噬细胞/小胶质细胞的活性。然而，激活素 A 对小胶质细胞迁移的影响尚不清楚。在这项研究中，使用鼠小胶质细胞 BV2 细胞研究了激活素 A 调节小胶质细胞迁移的作用。
通过酶联免疫吸附试验（ELISA）检测细胞因子水平。通过 Western blot 检测蛋白表达。通过实时细胞分析（RTCA）检测 BV2 细胞的黏附。通过 Transwell 室和微流控装置测定 BV2 细胞的迁移。通过转染 Smad3 或 Smad3 shRNA 表达质粒在 BV2 细胞中转染 Smad3 过表达或敲低。
激活素 A 抑制 BV2 细胞释放一氧化氮（NO）和促炎细胞因子 TNF-α和 IL-6，并抑制 TNF-α和 IL-6 mRNA 的表达。相反，激活素 A 促进 TGF-β1 的产生。激活素 A 抑制黏附，促进伤口愈合和迁移，这与 N-钙黏蛋白和 E-钙黏蛋白表达有关。此外，BV2 细胞中 Smad3 的过表达降低了 TNF-α和 IL-6 的水平，并促进了伤口愈合，而 Smad3 的敲低则显示出相反的效果。
这些发现表明，激活素 A 通过 Smad3 信号通路调节 BV2 细胞的生物学行为，提示激活素 A 可能成为神经系统中神经炎症和神经胶质瘢痕形成的潜在治疗靶点。
