Periodontal ligaments enhance neurite outgrowth in trigeminal ganglion neurons through Wnt5a production induced by mechanical stimulation
Periodontal ligaments enhance neurite outgrowth in trigeminal ganglion neurons through Wnt5a production induced by mechanical stimulation
复制标题
牙周膜通过机械刺激诱导 Wnt5a 的产生增强三叉神经节神经元的神经突生长
DOI：
10.1152/ajpcell.00302.2022
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发表时间：
2022
影响因子：
5.5
通讯作者：
Wakamori Minoru
中科院分区：
文献类型：
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作者：
Takahashi Kaori;Yoshida Takashi;Wakamori Minoru
必须维持外周感觉神经以感知环境变化。日常生理机械刺激，如重力、地板反作用力和咬合力，直接或间接地影响神经内稳态。虽然直接轴突膜拉伸通过机械敏感通道激活促进轴突生长，但间接机制仍有待阐明。在这项研究中，我们确定了间接途径，其中Wnt 5a是由机械刺激大鼠牙周膜（rPDL）细胞释放的分子线索。qRT-PCR和ELISA结果显示，机械刺激可促进rPDL细胞Wnt 5a的表达和Wnt 5a蛋白的表达，且呈Ca 2+依赖性。Western blotting结果显示，PI 3 K（LY 294002）和MEK 1/2（U 0126）抑制剂分别抑制Akt/PKB和ERK 1/2磷酸化，从而抑制Wnt 5a表达的增加。类似地，一种粘着斑激酶抑制剂PF 573228减弱Akt-和ERK 1/2-磷酸化和Wnt 5a表达。重要的是，拉伸PDL细胞的培养基增强了三叉神经节神经元投射到PDL的神经突伸长、发芽和分支。此外，用抗Wnt 5a抗体（中和Wnt 5a活性）、AP 7677 a（抗Ryk抗体，阻断Ryk受体活性）或strictinin（Ror 1抑制剂）处理抑制了形态学变化。这些发现揭示了Wnt 5a的间接机制，响应于机械刺激从结缔组织释放，增强周围神经的生长。我们的研究表明，周围结缔组织调节周围神经的稳态和Wnt 5a信号转导可以靶向周围神经疾病的治疗。
The peripheral sensory nerve must be maintained to perceive environmental changes. Daily physiological mechanical stimulations, like gravity, floor reaction force, and occlusal force, influence the nerve homeostasis directly or indirectly. Although the direct axonal membrane stretch enhances axon outgrowth via mechanosensitive channel activation, the indirect mechanisms remain to be elucidated. In this study, we identified the indirect pathways where Wnt5a was a molecular cue released by mechanically stimulated rat periodontal ligament (rPDL) cells. qRT-PCR and ELISA showed that mechanically stimulated rPDL cells enhancedWnt5aexpression level and Wnt5a protein in a Ca2+-dependent manner. The inhibitors of PI3K (LY294002) and MEK1/2 (U0126) suppressed the Akt/PKB and ERK1/2 phosphorylation, respectively, in Western blotting analysis and consequently abolished the increase inWnt5aexpression. Similarly, PF573228, a focal adhesion kinase inhibitor, attenuated Akt- and ERK1/2-phosphorylation andWnt5aexpression. Importantly, the culture medium of stretched PDL cells enhanced neurite elongation, sprouting, and branching in trigeminal ganglion neurons that project to PDL. Moreover, treatment with an anti-Wnt5a antibody (to neutralize Wnt5a activity), AP7677a (anti-Ryk antibody, to block Ryk receptor activity), or strictinin (Ror1 inhibitor) suppressed the morphological changes. These findings reveal the indirect mechanisms that Wnt5a, released from the connective tissues in response to mechanical stimulation, enhances the outgrowth of the peripheral nerves. Our study suggests that the peripheral connective tissues regulate peripheral nerve homeostasis and that Wnt5a signaling could be targeted for the treatment of peripheral nerve disorders.