Rheb调控的施旺细胞乳酸代谢参与外周神经损伤后轴突再生

Rheb-regulated lactate metabolism in Schwann cells implicates in axonal regeneration after peripheral nerve injury

  • 摘要: 外周神经损伤十分常见,但神经修复的治疗效果却不尽人意.施旺细胞作为外周神经系统主要的胶质细胞,会响应外周神经损伤参与轴突再生的全过程,但其在再生过程中的作用及机制仍有待进一步研究.本研究旨在探究施旺细胞中重要的能量调控因子Rheb对外周神经损伤后再生过程的影响,并分析可能的作用机制.利用施旺细胞特异性敲除Rheb转基因小鼠,构建坐骨神经压迫损伤模型,通过免疫荧光染色检测早期小鼠坐骨神经再生情况.通过对原代培养的DRG神经元添加乳酸或等量葡萄糖、添加乳酸转运蛋白抑制剂,检测并比较各组神经元突起再生情况.利用蛋白免疫印迹法检测体内外模型中p-AKT的表达水平.特异性敲除施旺细胞Rheb的小鼠外周神经轴突再生能力更强;敲除Rheb的施旺细胞乳酸产生增加,用乳酸处理DRG神经元后神经再生能力增加;Rheb缺失小鼠及乳酸处理的DRG神经元中p-AKT表达增加.Rheb缺失后,施旺细胞能够产生更多乳酸供给神经元,施旺细胞来源的乳酸会作为胞内信号分子通过调控PI3K-AKT通路参与到轴突再生的过程中.

     

    Abstract: Peripheral nerve injuries are prevalent; however, the efficacy of its repairment is often suboptimal. Schwann cells, the principal glial cells in the peripheral nervous system, play a critical role in the process of axon regeneration following peripheral nerve injury. Nevertheless, their specific role and underlying mechanisms in this regenerative process remain inadequately understood. This study aims to investigate the influence of Rheb, a significant energy regulator in Schwann cells, on axonal regeneration following peripheral nerve injury, as well as to analyze the potential mechanisms involved. Immunostaining using anti-SCG10 was employed to assess the regeneration length in Schwann cell-specific Rheb knockout mice (Rheb cKO) after sciatic nerve crush injury. The regeneration length of neurites was compared among groups after the administration of lactic acid or equivalent amounts of glucose and lactate transporter inhibitors to primary cultured dorsal root ganglion (DRG) neurons. Western blot analysis was conducted to measure the levels of phosphorylated AKT (p-AKT) in Rheb cKO mice and cultured DRG neurons. The findings indicated that axonal regeneration was enhanced in Rheb cKO mice. Additionally, the content and release of lactate were significantly elevated in Rheb knockout Schwann cells. Treatment with lactate promoted longer neurite regeneration in cultured DRG neurons. Furthermore, the expression of p-AKT in Rheb cKO mice and lactate-treated DRG neurons was found to be increased. The ablation of Rheb in Schwann cells leads to increased lactate production, providing essential support to neurons. The lactate derived from Schwann cells participates in the axonal regeneration process by modulating the PI3K-AKT signaling pathway, functioning as an intracellular signaling molecule.

     

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