CHEMOKINE RECEPTOR EXPRESSION IN THE CNS

描述（来自申请人的摘要）：项目的长期目标 旨在确定趋化因子及其受体在 中枢神经系统（CNS）功能。趋化因子是一组结构上 对多种细胞表现出多效性作用的相关细胞因子 但其功能主要是调节外周血 白细胞运动（即趋化性）和活化。趋化因子受体 已经描述了肽，它们是七种跨膜蛋白的成员。 G蛋白偶联受体超家族。表达趋化因子 外周血白细胞上的受体是有据可查的;这些受体中的一些 用CD 4介导HIV-1进入。最近，趋化因子及其 已经证明受体由CNS中的细胞表达，尽管 这种表达通常仅在神经病理学情况下是明显的。上 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CX 3CR 1在非病理性CNS中组成型表达。 利用原位杂交分析，已经确定小胶质细胞 表达CX 3CR 1 mRNA，而神经元是Fractalkine mRNA的主要来源 在大鼠中枢神经系统中。此外，这种配体：受体对的表达是 面神经运动核（FMN）损伤后的动态调节 周围神经横断这些数据提示了一个总体假设， 趋化因子依赖的信号传导机制介导独特的神经胶质细胞 在CNS的正常和损伤/修复状态下的相互作用。实验 本文提出的将最终提供对fractalkine的作用的见解 和CX 3CR 1在CNS功能中的作用。具体目标是： 1. CNS中fractalkine和CX 3CR 1蛋白表达的定位， 确定它们在神经元不表达的神经病理学中的表达谱 再生，例如新生儿面神经轴突切断术和红核脊髓束切断术。 2.评估小胶质细胞反应和神经元再生的程度， 成人FMN和红核，神经横断后（面神经轴突切断术或 红核脊髓束切断术），在缺乏fractalkine 或CX 3CR 1。 3.确定fractalkine的结构特征， CX 3CR 1激活。 该研究计划将利用广泛的方法，跨越体外和体内 实验范例这些研究旨在填补 关于趋化因子和特异性fractalkine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.