Altered nociception and neuronal migration

该奖项是根据2009年《美国复苏和再投资法案》(Public Law 111-5)资助的。Reelin是一种在卷轴小鼠中缺失的蛋白质，它与脂蛋白受体(VLDL/APOE2)结合，导致细胞内蛋白失活-1(Dab1)的磷酸化。带有Reelin、VLDLR和ApoER2或Dab1突变的小鼠在脊髓浅背角也有类似的迁移错误，脊髓浅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部位。首席研究员的实验室之前的研究发现了这些发育缺陷的功能相关性：对热的敏感度增加，对机械疼痛的敏感度降低。在这些疼痛模式上观察到的不同效果表明，Reelin信号通路突变自然地分离了热痛和机械性疼痛传递的生物学基础。这个项目的第一个目标是利用一个插入了蓝色报告基因(β-半乳糖苷酶)的“敲入”小鼠品系来鉴定Reelin信号通路突变体背角中错误定位的神经元。一旦确定了Reeler和dab1突变背角的定位错误，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误差与热伤害感受过程联系起来。解剖学、行为学和微扰实验将确定突变体中发现的热过敏是否是由背角浅层神经元错位引起的，这些神经元承载着神经激动素1(NK1)受体。由于NK1受体是P物质释放的伤害性感受器的靶标，推测浅背角内表达NK1的异位细胞可能与Reelin信号通路突变体的热敏感有关。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育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群体在研究职业中的教育和培训。

"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.