Exploring the Vestibulocerebellum- Vestibular Nuclei - Spinal Trigeminal Nucleus Causals communication and TRPV2 ion channel in vestibular migraine pathogenesis

Background Vestibular migraine (VM) is a disorder characterized by recurrent episodes of dizziness or vertigo and is often accompanied by headache. The mechanisms underlying vestibular dysfunction and pain in VM remain unclear. Methods Chronic migraine (CM) and VM models were induced by NTG and kainic acid, respectively. Behavioral assessments were conducted to evaluate vestibular dysfunction and pain in the VM and CM models. Transmission electron microscopy (TEM) was used to examine peripheral receptor impairment. Immunofluorescence, including staining for Cellular Proto-oncogene (c-Fos), Neuronal Nuclei (NeuN), and calcitonin gene-related peptide (CGRP), identified activated brain regions such as the cortex, midbrain, and cerebellum. Multiplex immunohistochemistry and cholera toxin subunit B (CTB) tracing were performed to analyze nuclear heterogeneity and neural communication. Additionally, RNA sequencing (RNA-Seq) and Ionized calcium-binding adapter molecule 1 (IBA1) immunostaining were used to investigate ion channel expression in the spinal trigeminal nucleus caudalis (Sp5c). Results CM and VM-related behaviors, such as allodynia and balance disturbance, were successfully reproduced in mouse model. TEM revealed significant damage to peripheral sensory receptors, particularly in the trigeminal ganglion and cochlear cells. Distinct activation patterns of c-Fos and CGRP were observed in VMs and CMs. CTB tracing confirmed that signals are transmitted from the vestibulocerebellum (VbC) to the Sp5c via the vestibular nuclei (VN). Furthermore, RNA-Seq combined with coimmunostaining revealed an increased expression of transient receptor potential vanilloid 2 (TRPV2) ion channels in microglia within Sp5c, indicating their potential role in VM pathology. Conclusions This study preliminarily explored VbC-VN-Sp5c communication and identified TRPV2 ion channels in microglia as key players in neuron-glia crosstalk in VM. These findings provide new insights into the mechanisms underlying vestibular migraine and suggest potential therapeutic targets. Overall design: Total RNA from the Sp5C nucleus was extracted to identify the most differentially expressed ion channels by comparing the data with the ion channel database.

背景 前庭性偏头痛（Vestibular Migraine, VM）是一种以反复发作性眩晕或头晕为特征，常伴随头痛的疾病，目前其前庭功能障碍与疼痛的潜在发病机制仍未明确。
方法 慢性偏头痛（Chronic Migraine, CM）与VM模型分别由硝酸甘油（NTG, Nitroglycerin）与红藻氨酸诱导构建。通过行为学评估检测VM与CM模型的前庭功能障碍及疼痛情况；采用透射电子显微镜（Transmission Electron Microscopy, TEM）观察外周感受器损伤情况；通过免疫荧光染色（包括细胞原癌基因（Cellular Proto-oncogene, c-Fos）、神经元核抗原（Neuronal Nuclei, NeuN）及降钙素基因相关肽（Calcitonin Gene-related Peptide, CGRP）染色），鉴定皮层、中脑及小脑等被激活的脑区；采用多重免疫组化及霍乱毒素B亚基（Cholera Toxin Subunit B, CTB）逆行追踪技术，分析核团异质性与神经通讯模式。此外，通过RNA测序（RNA Sequencing, RNA-Seq）及离子钙结合衔接分子1（Ionized calcium-binding adapter molecule 1, IBA1）免疫染色，探究三叉神经脊束核尾侧亚核（Spinal Trigeminal Nucleus Caudalis, Sp5c）内的离子通道表达情况。
结果 本研究成功在小鼠模型中复现了CM与VM相关的行为学表型，包括痛觉异常与平衡障碍。TEM观察显示，外周感觉感受器存在显著损伤，尤以三叉神经节与耳蜗细胞为甚。VM与CM模型中，c-Fos与CGRP呈现出截然不同的激活模式。CTB追踪实验证实，信号可通过前庭神经核（Vestibular Nuclei, VN）从前庭小脑（Vestibulocerebellum, VbC）传递至Sp5c。此外，RNA-Seq联合免疫共染色结果显示，Sp5c内小胶质细胞中的瞬时受体电位香草酸亚型2（Transient Receptor Potential Vanilloid 2, TRPV2）离子通道表达上调，提示其在VM病理进程中发挥潜在作用。
结论 本研究初步揭示了VbC-VN-Sp5c神经通路的通讯机制，并明确了小胶质细胞内的TRPV2离子通道作为VM神经元-胶质细胞交互的关键调控因子。本研究结果为阐明前庭性偏头痛的发病机制提供了新视角，并提示了潜在的治疗靶点。
整体实验设计：提取Sp5c核团的总RNA，通过与离子通道数据库比对，筛选差异表达最为显著的离子通道。