Objective: To investigate the regulatory effect of miR-132-3p on calmodulin-binding transcription activator 1 (CAMTA1) and Schwann cell activity in rats with facial nerve injury (FNI) treated with I-125 seeds.
Methods: Rat Schwann cells were irradiated with I-125 seeds and transfected with miR-132-3p mimic, miR-132-3p inhibitor or sh-CAMTA1. The expressions of S100B and β-tubulin Ⅲ in the cells were detected with immunofluorescence assay, and the expressions of miR-132-3p and CAMTA1 protein were determined using RT-qPCR and Western blotting, respectively. EdU staining and Transwell assay were used to evaluate the changes in cell proliferation and migration ability. In a rat model of FNI, I-125 seeds were implanted into the facial tissues near the facial nerve 2 weeks before modeling, and miR-132-3p mimic was injected subcutaneously in the face after modeling. The pathologies of the facial nerve was assessed by HE, LFB and immunofluorescence staining. The targeting relationship between miR-132-3p and CAMTA1 was verified using StarBase v2.0 database and dual-luciferase reporter assay.
Results: Rat Schwann cells showed high expressions of S100B and β-tubulin Ⅲ. I-125 seeds radiation significantly decreased miR-132-3p expression and repressed proliferation and migration of the cells (P < 0.001). Overexpression of miR-132-3p or CAMTA1 knockdown obviously enhanced proliferation and migration of the Schwann cells, while miR-132-3p knockdown produced the opposite effect. MiR-132-3p negatively regulated CAMTA1 expression. In the rat models of FNI, miR-132-3p injection significantly inhibited CAMTA1 expression and attenuated I-125 seeds-induced exacerbation of FNI.
Conclusion: Overexpression of miR-132-3p suppresses CAMTA1 expression and promotes Schwann cell proliferation and migration to alleviate I-125 seeds-induced exacerbation of FNI in rats.
目的: 探讨miR-132-3p通过钙调素结合转录因子1（CAMTA1）对I-125粒子处理的面神经损伤大鼠（FNI）中施万细胞的调控作用。
方法: 用I-125粒子辐射大鼠施万细胞，并在细胞中转染miR-132-3p mimic、miR-132-3p inhibitor以及sh-CAMTA1。免疫荧光检测S100B和β-Tubulin Ⅲ荧光强度。RT-qPCR检测miR-132-3p的表达，Western blot检测CAMTA1蛋白表达。EdU染色评估细胞增殖，Transwell检测细胞迁移。同时，构建FNI大鼠模型并在大鼠面部植入I-125粒子，HE、LFB染色以及IF染色评估大鼠面神经组织的病理损伤。StarBase v2.0数据库和双荧光素酶报告实验验证miR-132-3p和CAMTA1的靶向关系。
结果: S100B和β-Tubulin Ⅲ在大鼠施万细胞中显著表达。I-125粒子辐射组中miR-132-3p表达降低（P < 0.001），抑制细胞的增殖（P < 0.001）和迁移（P < 0.001）。过表达miR-132-3p或敲降CAMTA1显著促进施万细胞的增殖（P < 0.001）和迁移（P < 0.05），敲降miR-132-3p则具有相反的作用。机制研究显示，miR-132-3p靶向负调控CAMTA1。体内实验结果显示，过表达miR-132-3p通过抑制CAMTA1的蛋白表达，减弱I-125粒子对FNI大鼠面神经损伤的促进作用。
结论: 过表达miR-132-3p抑制CAMTA1的表达，促进施万细胞的增殖和迁移，抑制I-125对FNI大鼠面神经损伤的促进作用。
Keywords: calmodulin binding transcription activator 1; facial nerve injury; miR-132-3p; migration; proliferation; schwann cells.