Biochemical Modulation of Nociceptive Circuits

描述(申请人提供)：神经性疼痛是一种慢性和衰弱的疾病，很难用现有的止痛药治疗。最近的研究表明，溶血磷脂酸(LPA)受体激活在引起神经病理性疼痛中起着关键作用。我们发现许多直径较小的、可能是伤害性感受的背根神经节(DRG)和三叉神经节神经元表达一种跨膜定位的磷酸酶，该酶能使LPA去磷酸化。基于这些观察，我们的长期研究目标是证明这种磷酸酶在体外、使用培养的感觉神经元和在体内使用小鼠神经病理性疼痛模型来调节LPA受体信号。为了做到这一点，我们将首先使用免疫组织化学来表征表达这种磷酸酶的感觉神经元，并识别由含有磷酸酶的传入神经支配的外周组织。接下来，我们将使用钙成像和荧光素酶报告基因分析来验证这种磷酸酶调节细胞系和分离的小鼠DRG神经元中的LPA受体信号的假设。我们将使用表达绿色荧光蛋白的转基因小鼠来鉴定表达这种磷酸酶的DRG神经元。最后，我们将在野生型和磷酸酶基因敲除小鼠中测试这种磷酸酶调节神经病理性疼痛行为的假设。

DESCRIPTION (provided by applicant): Neuropathic pain is a chronic and debilitating disease that is difficult to treat with existing analgesics. Recent studies reveal a critical role for lysophosphatidic acid (LPA) receptor activation in causing neuropathic pain. We found that many small diameter, presumably nociceptive, dorsal root ganglia (DRG) and trigeminal neurons express a transmembrane-localized phosphatase that dephosphorylates LPA. Based on these observations, our long term research objectives are to demonstrate that this phosphatase modulates LPA receptor signaling in vitro, using cultured sensory neurons, and in vivo, using mouse neuropathic pain models. To accomplish this, we will first use immunohistochemistry to characterize the sensory neurons that express this phosphatase and identify the peripheral tissues that are innervated by phosphatase-containing afferents. Next, we will test the hypothesis that this phosphatase modulates LPA receptor signaling in cell lines and in dissociated mouse DRG neurons using calcium imaging and luciferase reporter gene assays. We will use genetically modified mice expressing Green Fluorescent Protein to identify the DRG neurons that express this phosphatase. Finally, we will test the hypothesis that this phosphatase modulates neuropathic pain behaviors in wild-type and phosphatase knockout mice.