Glial Signaling:Interplay of Connexins and P2 Receptors

描述(申请人提供)：星形胶质细胞相互通讯 通过传播的Ca+2波。信号既协调它们自己 并与神经元相互作用。负责该事件的机制 星形胶质细胞之间细胞间钙波的传播涉及两个 平行路径，一条依赖于缝隙连接，另一条依赖于缝隙 与结点无关。对于缝隙连接介导的钙波传播， 第二信使的扩散，如1P3、钙离子和/或环状ADP-核糖 跨越细胞边界是维持再生事件的关键。通过 相比之下，缝隙连接非依赖性机制依赖于细胞外 从一个细胞释放的嘌呤和嘧啶的扩散，然后激活 邻近细胞膜上的P2受体。我们最近获得了 Cx43基因缺失小鼠星形胶质细胞显示不同功能的P2Y的证据 与野生型小鼠星形胶质细胞亚型表达的比较表明 切换嘌呤受体亚型表达可显著影响 其中的钙波通过细胞外间隙传播。这些结果 从而得出总的假设，即嘌呤受体和缝隙连接 通道在功能上是相关的，Cx43通过这两种模式来调节 星形胶质细胞之间相互通信。有可能是不同的 不同连接蛋白形成的缝隙连接的选择性通透性 某些结构域介导的连接复合体的重塑 连接蛋白参与了连接蛋白和P2Y受体之间的相互作用。至 验证这些假设，我们将上调和下调Cx43的表达水平 和其他缝隙连接蛋白，并测量功能和表达的变化 缝隙连接通道存在与否对P2Y受体亚型的影响 拦截者。评估缝隙连接蛋白与血管内皮细胞生长因子表达的相互作用 P2Y受体是由Corinexin的特定结构域介导的，我们将表达 Cx43缺乏SH2/SH3或PDZ序列，并检测功能和 P2Y受体亚型的表达这种修饰的后果 将通过测量以下属性来评估细胞间通信 钙波传播与强度的耦合。预计到2010年， 星形细胞病中缝隙连接与P2受体相互作用的研究 细胞间通信，将揭示潜在的机制 规定远距离信元间信令可以传播的程度 在中枢神经系统内。

DESCRIPTION (provided by applicant): Astrocytes communicate with one another through propagated waves of Ca+2 .signaling both to coordinate their own activity and to interact with neurons. The mechanism responsible for the propagation of intercellular calcium waves between astrocytes involved two parallel pathways, one dependent on gap junctions and one that is gap junction-independent. For gap junction-mediated calcium wave propagation, diffusion of second messengers, such as 1P3, Ca2+, and/or cyclic ADP-ribose across cell boundaries is critical to sustain the regenerative event. By contrast, the gap junction-independent mechanism relies on the extracellular diffusion ofpurines and pyrimidmes released from one cell which then activates P2 receptors on the membranes of nearby cells. We have recently obtained evidence that astrocytes from Cx43 null mice display a different functional P2Y subtype expression compared to astrocytes from wildtype mice aTrd that this switch in purinoceptor subtype expression can markedly affect the extent to which calcium waves propagate through the extracellular space. These results thus lead to the overall hypothesis that purinoceptors and gap junction channels are functionally related, and that Cx43 regulates both modes by which astrocytes communicate with one another. It is possible that different selective permeabilities of gap junctions formed by different connexins or that remodeling of junctional complexes mediated through certain domains of connexins are involved in the interplay between connexins and P2Y receptors. To test these hypotheses we will up- and down-regulate expression levels of Cx43 and other gap junction proteins and measure changes in function and expression of P2Y receptor subtypes in the absence and presence of gap junction channel blockers. To evaluate whether the interplay between connexins and expression of P2Y receptors is mediated by specific domains of corinexins, we will express Cx43 lacking SH2/SH3 or PDZ sequences and test for changes in function and expression of P2Y receptor subtypes The consequences of such modification for cell-cell communication will be evaluated by measuring the properties of calcium wave spread and the strength of coupling. It is expected that by elucidating the interplay between gap junctions and P2 receptors in astrocytic intercellular communication, underlying mechanisms will be disclosed that dictate the extent to which long distance cell-to-cell signaling can propagate within the CNS.