CHEMOKINE RECEPTOR EXPRESSION IN THE CNS

描述(摘自申请者的摘要)：项目的长期目标 旨在确定趋化因子及其受体在体内的基础作用 中枢神经系统(CNS)功能。趋化因子在结构上是一组 对多种细胞表现出多效性的相关细胞因子 但其功能在很大程度上被描述为外周神经调节 白细胞的运动(即趋化)和激活。趋化因子受体 已经描述了多肽，它们是七种跨膜蛋白的成员 跨越，G蛋白偶联受体超家族。趋化因子的表达 外周血白细胞上的受体已有很好的文献记载；其中一些受体 用CD4介导HIV-1的进入。最近，趋化因子及其 受体已被证明由中枢神经系统的细胞表达，尽管 这种表达通常只有在神经病理情况下才明显。论 另一方面，一种独特的细胞表面表达的趋化因子配体，术语Fractalkine， 及其受体CX3CR1在非病理性中枢神经系统中有结构性表达。 利用原位杂交分析，已经确定小胶质细胞 表达CX3CR1 mRNA，而神经元是Fractalkine mRNA的主要来源 在大鼠中枢神经系统。此外，这个配体：受体对的表达是 大鼠面神经运动核损伤后的动态调节 周围神经横断术。这些数据促使人们做出总体假设： 趋化因子依赖的信号机制介导独特的神经胶质细胞 中枢神经系统正常和损伤/修复状态下的相互作用。实验 在此提出的建议将最终提供对Fractalkine的作用的见解 和中枢神经系统功能中的CX3CR1。具体目标包括： 1.定位Fractalkine和CX3CR1蛋白在中枢神经系统和 确定它们在神经元不能表达的神经病理中的表达情况 再生，例如新生儿面神经切断术和红脊髓束切断术。 2.评估小胶质细胞的反应和神经元再生的程度。 成年FMN和红核，神经切断后(面神经切断或 红核脊髓束切开术)，在任何一种Fractalkine缺陷的小鼠中 或CX3CR1。 3.确定所需的碎裂因子的结构特征 CX3CR1激活。 该研究计划将利用跨越体外和体内的广泛方法。 实验范式。这些研究旨在填补在以下方面的巨大空白 关于趋化因子，特别是分裂因子的作用的知识， 中枢神经系统功能的依赖机制。

DESCRIPTION (From the applicant's abstract): The long term goals of the project are aimed at determining fundamental roles of chemokines and their receptors in central nervous system (CNS) function. Chemokines are a group of structurally related cytokines that exhibit pleiotropic actions on a wide variety of cells but whose function has been largely characterized as regulators of peripheral leukocyte movement (i.e, chemotaxis) and activation. Receptors for chemokine peptides have been described and they are members of the seven transmembrane spanning, G-protein coupled receptor superfamily. Expression of chemokine receptors on pheripheral leukocytes is well documented; some of these receptors mediate, with CD4, entry of HIV-1. More recently, chemokines and their receptors have been demonstrated to be expressed by cells in the CNS, although this expression is often evident only in neuropathological situations. On the other hand, a unique cell surface-expressed chemokine ligand, term fractalkine, and its receptor CX3CR1, are constitutively expressed in non-pathological CNS. Utilizing in situ hybridization analysis, it has been determined that microglia express CX3CR1 mRNA, while neurons are the principle source of fractalkine mRNA in the rat CNS. In addition, the expression of this ligand:receptor pair is dynamically regulated in the injured rat facial motor nucleus (FMN) after peripheral nerve transection. These data prompt the overall hypothesis that chemokine-dependent signaling mechanisms mediate unique neuronal-glial cells interactions under normal and injury/repair states of the CNS. Experiments proposed herein will ultimately provide insights into the role of fractalkine and CX3CR1 in CNS function. The specific aims will: 1. map sites of expression of fractalkine and CX3CR1 protein in the CNS and determine their expression profiles in neuropathologies where neurons do NOT regenerate, e.g. neonatal facial nerve axotomy and rubrospinal tractotomy. 2. evaluate the microglial response and extent of neuronal regeneration in the adult FMN and red nucleus, after nerve transection (facial nerve axotomy or rubrospinal tractotomy, respectively), in mice deficient in either fractalkine or CX3CR1. 3. determine structural characteristics of fractalkine that are necessary for CX3CR1 activation. The research plan will utilize broad approaches that span in vitro and in vivo experimental paradigms. These studies are designed to fill large gaps in knowledge regarding the role of chemokine, and specfically fractalkine, dependent mechanisms in CNS function.