Mechanism of Calcium Channel Cava2d1 Protein Mediated Neuropathic Pain

描述（由申请人提供）：神经损伤引起的疼痛或神经性疼痛是一种常见的疾病，由于对潜在机制了解甚少，因此缺乏特异性治疗药物。周围神经损伤诱导背根神经节和脊髓中与神经性疼痛发展和维持相关的电压门控钙通道a2 d-1亚基（Cava 2d 1）表达，并且阻断这种增加导致神经性疼痛逆转。这表明Cava 2d 1在神经性疼痛的脊髓致敏中起着关键作用。为了进一步探讨损伤诱导Cava 2d 1上调介导的脊髓致敏和神经病理性疼痛的机制，我们计划验证以下假设：（1）损伤诱导的Cava 2d 1上调与损伤诱导的突触诱导剂血小板反应蛋白4（TSP 4）在背根神经节和脊髓中相互作用;（2）损伤诱导的Cava 2d 1和TSP 4均通过（3）促进脊髓突触发生而参与神经病理性疼痛的启动和维持。首先，我们将研究Cava 2d 1和TSP 4之间的空间和时间的相互作用，在背侧脊髓和背根神经节的神经病理性伤害感受，使用蛋白质印迹和免疫组织化学技术。第二，我们将比较TSP 4对在过度表达Cava 2d 1的转基因小鼠或Cava 2d 1表达升高的脊神经损伤大鼠中观察到的行为超敏反应的贡献。最后，我们将确定是否共同上调Cava 2d 1和TSP 4的神经损伤导致脊髓背角突触的增强，有助于神经病理性疼痛。这些研究的完成将使我们能够扩展我们目前对损伤诱导的Cava 2d 1上调机制及其对神经性疼痛的诱导和维持的贡献的认识。 公共卫生相关性：神经损伤引起的慢性疼痛或神经病理性疼痛是一种常见的临床综合征，由于其细胞机制知之甚少，缺乏特异性和有效的治疗药物。现有资料表明，损伤诱导的背根神经节和脊髓中的电压门控性钙通道a2 d-1亚基（Cava 2d 1）参与了神经病理性疼痛的发生。然而，损伤诱导Cava 2d 1在神经性疼痛中的潜在机制尚不清楚。我们推测，Cava 2d 1的升高与血小板反应蛋白-4（TSP-4）在促进突触形成中的损伤后相互作用，而异常的突触形成在神经病理性疼痛中起着因果作用。我们将使用转基因小鼠、神经损伤模型、生物化学、电生理学和行为药理学方法来验证这一假设。本研究的完成将为神经病理性疼痛机制的理解和下一代神经病理性疼痛药物的开发提供重要信息。

DESCRIPTION (provided by applicant): Nerve injury-induced pain, or neuropathic pain, is a common disorder lacking specific therapeutic agents due to the fact that underlying mechanisms are poorly understood. Peripheral nerve injury induces voltage-gated calcium channel a2d-1 subunit (Cava2d1) expression in dorsal root ganglia and spinal cord that correlates with neuropathic pain development and maintenance, and blocking such an increase results in neuropathic pain reversal. These suggest that Cava2d1 plays a critical role in spinal sensitization that underlies neuropathic pain. To further explore the mechanism underlying spinal sensitization and neuropathic pain mediated by injury-induced Cava2d1 upregulation, we plan to test the hypotheses that (1) injury-induced upregulation of the Cava2d1 interacts with injury-induced synapse inducer, thrombospondin-4 (TSP4) in dorsal root ganglia and spinal cord; (2) Both injury-induced Cava2d1 and TSP4 contribute to initiation and maintenance of neuropathic pain by (3) promoting spinal synaptogenesis. First, we will examine the spatial and temporal interactions between Cava2d1 and TSP4 in dorsal spinal cord and DRG in relation to neuropathic nociception using Western blots and immunohistochemical techniques. Second, we will compare the contribution of TSP4 to behavioral hypersensitivity observed in transgenic mice overexpressing the Cava2d1 or spinal nerve injured rats with elevated Cava2d1 expression. Finally, we will determine if co-upregulation of Cava2d1and TSP4 by nerve injury leads to enhanced synaptogenesis in the spinal dorsal horn that contributes to neuropathic pain. Completion of these studies will allow us to extend our current knowledge about the mechanisms of injury-induced Cava2d1 upregulation and its contribution to the induction and maintenance of neuropathic pain. PUBLIC HEALTH RELEVANCE: Chronic pain derived from nerve injury, or neuropathic pain, is a common clinical syndrome lacking specific and effective therapeutic agents due to the fact that its cellular mechanisms are poorly understood. Existing data indicate that injury-induced voltage-gated calcium channel a2d-1 subunit (Cava2d1) in dorsal root ganglia and spinal cord contributes to the development of neuropathic pain. However, mechanisms underlying injury-induced Cava2d1 in neuropathic pain are not known. We hypothesize that elevated Cava2d1 interacts with thrombospondin-4 (TSP4) post injury in promoting synapse formation, and abnormal synapse formation plays a causal role in neuropathic pain. We will test this hypothesis using genetically modified mice, nerve injury models, biochemical, electrophysiological, and behavioral pharmacology approaches. Completion of this study will provide important information for the understanding of neuropathic pain mechanisms and the development of next generation of neuropathic pain medications.