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。

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.