中国神经再生研究(英文版)

中国神经再生研究(英文版) ›› 2022, Vol. 17 ›› Issue (5): 1072-1079.doi: 10.4103/1673-5374.324858

• 原著:神经损伤修复保护与再生 • 上一篇    下一篇

脊髓损伤后M1型小胶质细胞可促进星形胶质细胞中硫酸软骨素蛋白多糖沉积

  

  • 出版日期:2022-05-15 发布日期:2021-11-22

M1-type microglia can induce astrocytes to deposit chondroitin sulfate proteoglycan after spinal cord injury

Shui-Sheng Yu#, Zi-Yu Li#, Xin-Zhong Xu, Fei Yao, Yang Luo, Yan-Chang Liu, Li Cheng*, Mei-Ge Zheng*, Jue-Hua Jing*   

  1. Department of Orthopedics, The Second Hospital of Anhui Medical University, Hefei, Anhui Province, China
  • Online:2022-05-15 Published:2021-11-22
  • Contact: Jue-Hua Jing, MD, PhD, jjhhu@sina.com; Mei-Ge Zheng, PhD, zhengmg113@126.com; Li Cheng, MS, chengli7788@163.com.
  • Supported by:
    This work was supported by the National Natural Science Foundation of China, Nos. 81801220 (to MGZ), 81671204 (to JHJ); and Key Research and Development Projects of Anhui Province of China, No. 202004j07020042 (to JHJ). 

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摘要：

脊髓损伤后，星形胶质细胞逐渐迁移并包围损伤核心，沉积以硫酸软骨素蛋白多糖为主的细胞外基质，继而形成星形胶质瘢痕，从而限制炎症的扩散并阻碍轴突的再生。同时，小胶质细胞也在病变边缘逐渐聚集并形成小胶质瘢痕，并在极化成促炎M1表型或抗炎M2表型。但是脊髓损伤后小胶质细胞极化对星形胶质细胞的影响尚不清楚。实验发现（1）小胶质细胞(CX3C趋化因子受体1阳性细胞)和星形胶质细胞(胶质纤维酸性蛋白阳性细胞)在损伤后14d均都聚集在损伤边缘，其中小胶质细胞与星形胶质细胞内侧相邻，因而提示2种细胞间存在直接接触。（2）M1型小胶质细胞（诱导型一氧化氮合酶/CX3C趋化因子受体1双阳性细胞）主要于损伤后3和7d时可见，而M2型小胶质细胞（精氨酸酶1/CX3C趋化因子受体1双阳性细胞）则在7和14d时增加。（3）转化生长因子β1在体外M1型小胶质细胞中高表达，且在体内模型中也可见小胶质细胞在脊髓损伤后3和7 d时高表达转化生长因子β1。（4）M1型小胶质细胞培养基上清液在体外可促进星形胶质细胞分泌硫酸软骨素蛋白多糖，其作用可通过敲低星形胶质细胞中Y染色体性别决定区盒转录因子9而消除，且消除作用无法通过添加转化生长因子β1逆转。（5）结果说明，小胶质细胞可在脊髓损伤后3和7d时呈M1极化并高表达转化生长因子β1，且M1型小胶质细胞可能通过转化生长因子β1/ Y染色体性别决定区盒转录因子9通路促进脊髓损伤后星形胶质细胞中硫酸软骨素蛋白多糖的沉积。实验于2016年3月1日经安徽医科大学动物伦理委员会批准（批准号LLSC20160052）。

https://orcid.org/0000-0001-5599-5672 (Jue-Hua Jing); https://orcid.org/0000-0002-1071-9903 (Shui-Sheng Yu)

关键词: 脊髓损伤, 小胶质细胞, M1极化, M2极化, 星形胶质细胞, 转化生长因子β1, Y染色体性别决定区盒转录因子9, 星形胶质细胞瘢痕, 硫酸软骨素蛋白多糖

Abstract: After spinal cord injury (SCI), astrocytes gradually migrate to and surround the lesion, depositing chondroitin sulfate proteoglycan-rich extracellular matrix and forming astrocytic scar, which limits the spread of inflammation but hinders axon regeneration. Meanwhile, microglia gradually accumulate at the lesion border to form microglial scar and can polarize to generate a pro-inflammatory M1 phenotype or an anti-inflammatory M2 phenotype. However, the effect of microglia polarization on astrocytes is unclear. Here, we found that both microglia (CX3CR1+) and astrocytes (GFAP+) gathered at the lesion border at 14 days post-injury (dpi). The microglia accumulated along the inner border of and in direct contact with the astrocytes. M1-type microglia (iNOS+CX3CR1+) were primarily observed at 3 and 7 dpi, while M2-type microglia (Arg1+CX3CR1+) were present at larger numbers at 7 and 14 dpi. Transforming growth factor-β1 (TGFβ1) was highly expressed in M1 microglia in vitro, consistent with strong expression of TGFβ1 by microglia in vivo at 3 and 7 dpi, when they primarily exhibited an M1 phenotype. Furthermore, conditioned media from M1-type microglia induced astrocytes to secrete chondroitin sulfate proteoglycan in vitro. This effect was eliminated by knocking down sex-determining region Y-box 9 (SOX9) in astrocytes and could not be reversed by treatment with TGFβ1. Taken together, our results suggest that microglia undergo M1 polarization and express high levels of TGFβ1 at 3 and 7 dpi, and that M1-type microglia induce astrocytes to deposit chondroitin sulfate proteoglycan via the TGFβ1/SOX9 pathway. The study was approved by the Institutional Animal Care and Use Committee of Anhui Medical University, China (approval No. LLSC20160052) on March 1, 2016.

Key words: astrocytes, astrocytic scar, chondroitin sulfate proteoglycan, M1/M2 polarization, microglia, sex-determining region Y-box 9, spinal cord injury, transforming growth factor-β1

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