Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University; Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215123, China.
Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, United States.
Theranostics. 2022 May 16;12(9):4288-4309. doi: 10.7150/thno.70929. eCollection 2022.
Grafted astroglia/astrocytes exhibit neuroprotective effects and improve functional recovery after injury to the central nervous system. This study sought to elucidate their ability to repair spinal cord lesions and the underlying mechanisms. Complete spinal transection, transplantation of astroglia generated from human ESC-derived neural progenitor cells (NPC-Astros) or Olig2-GFP knock-in progenitors (Olig2PC-Astros), and immunostaining were used to determine the survival of astroglia. CUBIC tissue-clearing, immunostaining, electromyography, and functional tests such as the Basso Mouse Scale score and gait analysis were applied to analyze the recovery of the lesion area, axon regeneration, synapse formation, and motor function. Sholl analysis, immunostaining, depletion of anti-inflammatory microglia, and western blotting were employed to explore the cellular and molecular mechanisms underlying spinal cord repair. Grafted NPC- or Olig2PC-Astros survived in the lesion area and assisted wound healing by reducing scar formation and promoting regrowth of descending serotonergic axons and synapse reformation beyond the lesion area. These positive effects resulted in increased Basso Mouse Scale scores and improved hindlimb function as determined by electromyography and gait analysis. Activated microglia in the lesion area were shifted towards an anti-inflammatory phenotype after transplantation of NPC- or Olig2PC-Astros, and depletion of anti-inflammatory microglia reversed the observed improvements in the lesion area and axon regeneration. Transplantation of NPC- or Olig2PC-Astros elevated the expression of interleukin-4 and promoted the phenotypic shift of microglial via interleukin-4 downstream signaling. Our findings indicate that grafted human ESC-derived NPC- or Olig2PC-Astros promote recovery of the injured spinal cord by shifting microglia towards an anti-inflammatory state in the lesion area and activating interleukin-4 signaling.
移植的星形胶质细胞/星形细胞具有神经保护作用，并改善中枢神经系统损伤后的功能恢复。本研究旨在阐明其修复脊髓损伤的能力及其潜在机制。采用完全性脊髓横断、人 ESC 来源的神经前体细胞（NPC-Astros）或 Olig2-GFP 敲入祖细胞（Olig2PC-Astros）生成的星形胶质细胞移植、免疫染色，以确定星形胶质细胞的存活情况。采用 CUBIC 组织清除、免疫染色、肌电图和功能测试，如 Basso 小鼠评分和步态分析，以分析损伤区域的恢复、轴突再生、突触形成和运动功能。Sholl 分析、免疫染色、抗炎性小胶质细胞耗竭和 Western blot 分析用于探讨脊髓修复的细胞和分子机制。移植的 NPC 或 Olig2PC-Astros 存活在损伤区域，通过减少疤痕形成和促进下行 5-羟色胺能轴突的再生和突触再形成超过损伤区域，有助于伤口愈合。这些积极作用导致 Basso 小鼠评分增加，电生理和步态分析显示后肢功能改善。移植 NPC 或 Olig2PC-Astros 后，损伤区域的激活小胶质细胞向抗炎表型转变，而抗炎性小胶质细胞耗竭则逆转了损伤区域和轴突再生观察到的改善。移植 NPC 或 Olig2PC-Astros 可上调白细胞介素 4 的表达，并通过白细胞介素 4 下游信号通路促进小胶质细胞的表型转变。我们的研究结果表明，移植的人 ESC 来源的 NPC 或 Olig2PC-Astros 通过在损伤区域将小胶质细胞向抗炎状态转变并激活白细胞介素 4 信号通路，促进损伤脊髓的恢复。
