HIV ENV & MACROPHAGE CHEMOKINE RECEPTOR IONIC SIGNALING

描述：趋化因子受体CCR 5和CXCR 4作为共受体， HIV-1进入。因为它们的正常功能是响应于 趋化因子HIV-1 gp 12 O也可以激活细胞内信号， 通过改变病毒进入、进入后步骤或 细胞功能除了感染。Ca+2升高或蛋白磷酸化 在淋巴样细胞中已经报道了通过CCR 5或CXCR 4对gp 12 O的应答 在一些但不是所有的研究中。虽然共受体信号传导结构域是 对于转染细胞系中的进入，最近的研究表明， 信号传导可影响某些原代细胞中的进入或进入后感染步骤。 巨噬细胞表达CD 4、CCR 5和CXCR 4，是HIV-1的重要靶点， 体内，但gp 120/趋化因子受体信号转导尚未在它们中得到解决。 事实上，对于趋化因子的作用机制， 受体信号传导。在初步研究中， 发现gp 12 O在原代人类巨噬细胞中启动细胞内信号 通过CCR 5和CXCR 4激活K+、Cr和非选择性阳离子通道， 升高细胞内Ca +。R5和X5 gp 12 O在定性上相似，但 数量上不同的反应，出乎意料的是，离子的模式 由gp 120引起的通道信号传导不同于由gp 120引起的通道信号传导。 受体的天然趋化因子配体。我们的假设是HIV-1 Env 在巨噬细胞中通过共受体启动细胞内信号， 导致细胞功能、病毒进入和/或 进入后的感染步骤。 为了更好地理解趋化因子受体信号转导机制， gp 120（以及趋化因子）激活巨噬细胞中的通道，以及 gp 120介导的巨噬细胞功能和感染信号的结果，我们 将（a）定义原代巨噬细胞中激活的离子信号传导途径 通过gp 120使用原代和原型HIV- 1和SIV毒株以及 利用巨噬细胞趋化因子受体和趋化因子的能力不同; (b)确定趋化因子受体离子信号传导的机制， 通过定义CCR 5和CXCR 4与K+、Cl-和非选择性阳离子的偶联， 通道，CD 4共同参与的作用，Ca 2升高的来源和耦合，以及 CCR 5中涉及的结构元件;（c）确定Env信号传导的作用 在巨噬细胞中的进入、感染和复制，包括形成和 gp 12 O诱导的加帽以及进入后事件的意义，以及;（d） 确定gp 120信号传导对巨噬细胞功能的影响， 介质的异常分泌、吞噬作用和杀伤作用。

DESCRIPTION: The chemokine receptors CCR5 & CXCR4 serve as co-receptors for HIV-1 entry. Since their normal function is to transduce signals in response to chemokines, HIV-1 gp12O could also activate intracellular signals, with consequences for pathogenesis by modifying viral entry, post-entry steps or cell functions apart from infection. Ca+2 elevations or protein phosphorylation responses to gp12O through CCR5 or CXCR4 have been reported in lymphoid cells in some but not all studies. While co-receptor signaling domains are dispensable for entry in transfected cell lines, recent studies suggest that signaling may affect entry or post-entry infection steps in some primary cells. Macrophages express CD4, CCR5 & CXCR4, and are important targets of HIV-1 in vivo but gpl2O/chemokine receptor signaling has not been addressed in them. Indeed, relatively little is known in general about mechanisms of chemokine receptor signaling in primary macrophages. In preliminary studies, we have found that gp12O initiates intracellular signals in primary human macrophages through CCR5 & CXCR4, activates K+, Cr, & non-selective cation channels, and elevates intracellular Ca +. R5 and X5 gp12O elicited qualitatively similar but quantitatively different responses and, unexpectedly, the patterns of ion channel signaling elicited by gp120 differed from those elicited by the receptors' natural chemokine ligands. Our hypothesis is that HIV-1 Env initiates intracellular signals in macrophages through the co-receptors that lead to critical alterations in cellular function, virus entry, and/or post-entry steps of infection. To better understand the mechanisms of chemokine receptor signaling & ion channel activation in macrophages by gp120 (as well as chemokines), and consequences of gp120-mediated signals for macrophage function & infection, we will (a) Define the ionic signaling pathways activated in primary macrophages by gp 120 using primary & prototype HIV- 1 & SIV strains and strains that differ in ability to utilize macrophage chemokine receptors, and chemokines; (b) Identify the mechanisms of chemokine receptor ionic signaling in macrophages by defining CCR5 & CXCR4 coupling to K+, Cl- & non-selective cation channels, role of CD4 co-engagement, source & coupling for Ca2 elevations, and structural elements in CCR5 involved; (c) Determine the role of Env signaling in entry, infection & replication in macrophages, including the formation & significance of gp12O-induced capping as well as post-entry events, and; (d) Determine the effects of gp120 signaling on macrophage function such as aberrant secretion of mediators, phagocytosis, and killing.