Altered nociception and neuronal migration

“该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。“Reelin是reeler小鼠中缺失的蛋白质，与脂蛋白受体（VLDL/ApoE 2）结合，并导致细胞内蛋白Disabled-1（Dab 1）磷酸化。 在Reelin，VLDLR和ApoER 2或Dab 1中突变的小鼠在脊髓的浅层背角中具有类似的迁移错误，脊髓的浅层背角是将疼痛信息传递到中枢神经系统的初级感觉神经元的终止位点。 首席研究员实验室先前的研究发现了这些发育缺陷的功能相关性：对热的敏感性增加，对机械疼痛的敏感性降低。 在这些疼痛模式上观察到的差异效应表明，Reelin信号传导途径突变体自然地分离了热和机械疼痛传递的生物学基础。该项目的第一个目的是使用在Dab 1位点插入蓝色报告基因（β-半乳糖苷酶）的“敲入”小鼠系来鉴定Reelin信号通路突变体背角中的错位神经元。 一旦reeler和dab 1突变背角的定位错误被确定，他们将使用胚胎切片培养来研究突变背角的迁移缺陷。 第二个目标是将迁移错误与热伤害性加工联系起来。 解剖，行为和扰动实验将确定突变体中发现的热超敏反应是否是由浅背角中携带神经激肽1（NK 1）受体的错误定位神经元引起的。 由于NK 1受体是P物质释放伤害感受器的靶点，因此预期浅表背角内的异位NK 1表达细胞可能是导致Reelin信号通路突变体中的热超敏反应的原因。两名本科生研究员和一名博士后研究员将在进行与该项目相关的实验时接受指导和研究培训。 更广泛的影响将是促进发展神经生物学的研究和教学活动的整合，并支持本科生和少数民族的教育和研究生涯的培训。

"This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5)."Reelin, the protein missing in reeler mice, binds to lipoprotein receptors (VLDL/ApoE2) and causes phosphorylation of the intracellular protein Disabled-1 (Dab1). Mice with mutations in Reelin, VLDLR and ApoER2, or Dab1 have similar migratory errors in the superficial dorsal horn of the spinal cord, the termination site for primary sensory neurons that convey pain information into the central nervous system. Previous studies by the principal investigator's laboratory found a functional correlate of these developmental defects: an increased sensitivity to heat and a decreased sensitivity to mechanical pain. The differential effects observed on these pain modalities suggested that Reelin-signaling pathway mutants naturally segregate the biological basis of thermal and mechanical pain transmission. The first aim of this project is to identify the mis-positioned neurons in the dorsal horn of Reelin-signaling pathway mutants using a "knock-in" mouse line with a blue reporter gene (beta-galactosidase) inserted in the Dab1 locus. Once the positioning errors in reeler and dab1 mutant dorsal horns are identified, they will use embryonic slice cultures to study the migratory defects in the mutant dorsal horn. The second aim will link the migratory errors to thermal nociceptive processing. Anatomical, behavioral, and perturbation experiments will determine if the heat hypersensitivity found in mutants is caused by mis-positioned neurons in the superficial dorsal horn that bear Neurokinin1 (NK1) receptors. Because the NK1 receptor is the target of the substance P-releasing nociceptors, it is expected that the ectopic NK1-expressing cells within the superficial dorsal horn are likely responsible for the heat hypersensitivity in Reelin-signaling pathway mutants. Two undergraduate student researchers and a post-doctoral fellow will receive mentoring and research training as they conduct experiments related to this project. The broader impact will be to facilitate integration of research and teaching activities in developmental neurobiology and to support undergraduate and minority education and training in research careers.