Activation of the Wnt/β-catenin signaling cascade after traumatic nerve injury.
Activation of the Wnt/β-catenin signaling cascade after traumatic nerve injury.
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DOI：
10.1016/j.neuroscience.2015.02.049
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发表时间：
2015-05-21
期刊：
影响因子：
3.3
通讯作者：
Gupta R
中科院分区：
文献类型：
--
作者：
Kurimoto S;Jung J;Tapadia M;Lengfeld J;Agalliu D;Waterman M;Mozaffar T;Gupta R
最近的数据表明，创伤神经损伤后保留神经肌肉接头(NMJ)有助于通过阻断基质金属蛋白酶-3(MMP3)的手术修复来促进功能恢复。因此，我们试图探索可能增强这种反应的其他途径。WNT3a已被证明在NMJ的发展中通过β依赖的连环蛋白信号通路抑制乙酰胆碱受体(AChR)的聚集。因此，我们假设WNT3a和β-连环蛋白与创伤性失神经后的NMJ失稳有关。通过切除一段10毫米长的小鼠坐骨神经，造成了一个临界大小的神经缺损。然后在多个时间点采集失神经肌肉，进行免疫荧光染色、实时定量聚合酶链式反应和蛋白质印迹分析WNT3a和β-catenin水平。此外，一个新的Wnt/β-catenin转基因报告鼠系被用来支持我们的假设，即创伤神经损伤后Wnt被激活。Wnt3a基因的表达在伤后2周显著升高，并持续表达2个月。此外，与对照组相比，β-连环蛋白在损伤后2个月被激活。相应地，失神经转基因小鼠系TCF/Lef：H_2B-GFP肌肉的免疫组织化学分析表明，运动终板带的GFP阳性细胞数量增加。这些集体数据支持突触后AChRs在失神经后通过涉及Wnt/β-Catenin途径的过程而不稳定。因此，该通路可作为预防创伤性神经损伤后发生的运动终板变性的潜在治疗靶点。
Recent data have shown that preservation of the neuromuscular junction (NMJ) after traumatic nerve injury helps to improve functional recovery with surgical repair via matrix metalloproteinase-3 (MMP3) blockade. As such, we sought to explore additional pathways that may augment this response. Wnt3a has been shown to inhibit acetylcholine receptor (AChR) clustering via β-catenin-dependent signaling in the development of the NMJ. Therefore, we hypothesized that Wnt3a and β-catenin are associated with NMJ destabilization following traumatic denervation. A critical size nerve defect was created by excising a 10-mm segment of the sciatic nerve in mice. Denervated muscles were then harvested at multiple time points for immunofluorescence staining, quantitative real-time PCR, and western blot analysis for Wnt3a and β-catenin levels. Moreover, a novel Wnt/β-catenin transgenic reporter mouse line was utilized to support our hypothesis of Wnt activation after traumatic nerve injury. The expression of Wnt3a mRNA was significantly increased by 2 weeks post-injury and remained upregulated for 2 months. Additionally, β-catenin was activated at 2 months post-injury relative to controls. Correspondingly, immunohistochemical analysis of denervated transgenic mouse line TCF/Lef:H2B-GFP muscles demonstrated that the number of GFP-positive cells was increased at the motor endplate band. These collective data support that post-synaptic AChRs destabilize after denervation by a process that involves the Wnt/β-catenin pathway. As such, this pathway serves as a potential therapeutic target to prevent the motor endplate degeneration that occurs following traumatic nerve injury.