Netrin-1调控AMPK-ULK1通路诱导自噬对周围神经病理性疼痛的作用

Neuropathic pain (NP) severely affects life quality, and the underlying mechanisms remain unclear. Our preliminary data show for the first time that the knockdown of Unc5H2 (the receptor of netrin-1, an axon growth guidance factor) exaggerated allodynia induced by chronic constrictive injury (CCI) of sciatic nerve in rats. We also found that netrin-1 can rescue the survival of Schwann cells by activating autophagy, and the inhibition of autophagy aggravated NP. It is known that netrin-1 is genetically related to ULK1 (autophagy related gene 1), and can activate AMPK which is an upstream activator of autophagy. Therefore, we raised our hypothesis: netrin-1 ameliorates NP by enhancing neural regeneration and inhibiting inflammation, mediated by AMPK-ULK1 regulated autophagic activation. First, adenovirus-associated virus transfection, siRNA and neutralizing antibodies will be applied in CCI model, neuroplasticity, inflammation, behavior and neuroelectrophysiological tests will be performed, in order to investigate the effects of netrin-1 induced autophagy on NP. Second, Schwann cells will be cultured, different interfering methods will be used to detect the regulating pathway of netrin-1 in the activation of autophagy. The proposed study will reveal the underlying mechanism of netrin-1 and its receptors in the regulation of NP, thus reveal a potential new target for the management of NP.

神经病理性疼痛（NP）严重影响生活质量。我们发现，轴索导向因子netrin-1受体Unc5H2基因沉默可抑制自噬，降低损伤后施万细胞存活，并加重坐骨神经慢性压迫所致NP，提示netrin-1可能通过自噬参与NP的发生，其机制尚不清楚。已经证实，自噬相关基因ULK1参与Unc5H2的胞内定位，并受AMPK调控，后者可被netrin-1激活并参与一系列炎性反应，影响细胞存活。我们假设netrin-1可通过AMPK-ULK1途径调控自噬，促进神经修复和抑制炎症而改善NP。本研究将建立坐骨神经慢性压迫NP模型，以病毒转染补充netrin-1，同时以siRNA干扰其受体，以及自噬相关因子，明确netrin-1在不同受体介导下对NP的作用及途径，探讨netrin-1对自噬的调控机制；同时，应用抗体中和炎性细胞因子，阐明自噬介导抗炎机制在NP形成中的作用。研究结果对发现治疗新靶点、改善NP有重要意义。

神经病理性疼痛严重影响生活质量。轴索导向因子netrin-1与其受体结合，影响神经修复过程。在前期研究基础上，我们已提出假设：周围神经netrin-1可通过Unc5H2-ULK1途径调控自噬，促进神经修复而改善神经病理性疼痛。本研究建立了坐骨神经慢性压迫大鼠模型，及培养的施万细胞糖氧剥夺模型，体内外干预Unc5H2，检测动物的行为学评分、坐骨神经形态学变化、细胞自噬及凋亡等。我们发现，敲低Unc5H2加重机械性触诱发痛，反之表达Unc5H2减轻机械性触诱发痛并促进神经修复；坐骨神经损伤后自噬被激活但自噬流受阻，Unc5H2参与促进自噬流，可能与其促进ULK1磷酸化有关；体外培养施万细胞的糖氧剥夺模型中也揭示了Unc5H2促进自噬流、抑制细胞凋亡的作用。本研究首次揭示了调控周围神经Unc5H2通过自噬对于NP的影响，有助于探讨新的治疗靶点，具有重要的科研和临床价值。