Miao Li, Qing Sun Wan, Tao Lu
Department of Orthopedics, Hunan Children's Hospital, Changsha, China.
The School of Pediatrics, Hengyang Medical School, University of South China, Changsha, China.
Front Mol Neurosci. 2023 Aug 7;16:1214150. doi: 10.3389/fnmol.2023.1214150. eCollection 2023.
Huntingtin-associated protein 1 (HAP1) is a neuronal protein closely associated with microtubules and might facilitate neurological function rehabilitation. This study aimed to investigate the effects of HAP1 on SCI and the underlying mechanisms.
the spinal cord injury (SCI) mouse model was induced by Allen's method. Then recombinant-HAP1 (r-HAP1) was administrated by intrathecal injection, and the BMS, Thermal nociceptive thresholds, tactile nociceptive thresholds, and neurofibrillary regeneration were identified to inspect the therapy outcome. Then NSCs were isolated from mice on embryonic day 14.5 and induced to differentiate into neurons. The efficiency of axon growth was calculated. Signaling pathway array was conducted to examine the signaling pathways in NSCs treated with r-HAP1. Antagonists and activators of TrkA were used to confirm the role of TrkA of HAP1 intervention both and .
r-HAP1 ameliorates the neurological function rehabilitation after SCI, and benefits the regain of Tuj in injury spinal cord. Also significantly enhances neurite growth during neuronal differentiation of NSCs; Signaling pathway array and Western blot revealed that r-HAP1 significantly activates the phosphorylation of TrkA-MAPK/ERK in NSCs. TrkA selective inhibitor GW441756 blocks r-HAP1 on TrkA-MAPK/ERK signaling pathway and detracts from axonal growth after neuronal differentiation. TrkA selective activator gambogic amide can mimic the function of r-HAP1 by activating the foregoing pathway. ERK activator U-46619 reverses the blocking effect of GW441756 on r-HAP1.
HAP1 activates the TrkA-MAPK signaling pathway and is conducive to neurite elongation during NSC neuronal differentiation; by which to improve the prognosis of spinal cord injury in mice.
亨廷顿蛋白相关蛋白1（HAP1）是一种与微管密切相关的神经元蛋白，可能促进神经功能恢复。本研究旨在探讨HAP1对脊髓损伤（SCI）的影响及其潜在机制。
采用Allen法建立脊髓损伤小鼠模型。然后通过鞘内注射给予重组HAP1（r-HAP1），并通过BMS、热痛觉阈值、触觉痛觉阈值和神经纤维再生来评估治疗效果。然后从胚胎第14.5天的小鼠中分离神经干细胞（NSCs）并诱导其分化为神经元。计算轴突生长效率。进行信号通路阵列检测用r-HAP1处理的NSCs中的信号通路。使用TrkA的拮抗剂和激活剂来确认HAP1干预的TrkA在体内和体外的作用。
r-HAP1改善SCI后的神经功能恢复，并有利于损伤脊髓中Tuj的恢复。还显著增强了NSCs神经元分化过程中的神经突生长；信号通路阵列和蛋白质免疫印迹显示，r-HAP1显著激活NSCs中TrkA-MAPK/ERK的磷酸化。TrkA选择性抑制剂GW441756阻断r-HAP1对TrkA-MAPK/ERK信号通路的作用，并降低神经元分化后的轴突生长。TrkA选择性激活剂藤黄酰胺可通过激活上述通路模拟r-HAP1的功能。ERK激活剂U-46619可逆转GW441756对r-HAP1的阻断作用。
HAP激活TrkA-MAPK信号通路，有利于NSCs神经元分化过程中的神经突伸长；从而改善小鼠脊髓损伤的预后。
