Neuroprotective roles for apelin in HIV-associated excitotoxic injury

描述(由申请人提供)：通过激活N-甲基-D-天冬氨酸受体(NMDAR)造成的兴奋毒性神经元损伤与多种神经退行性疾病有关，包括人类免疫缺陷病毒(HIV)相关的神经认知障碍(IHand)。这项建议的广泛目标是提高我们对促进神经元存活的信号通路的理解，从而提高我们开发治疗手部和相关神经退行性疾病的方法的能力。HIV诱导的神经毒性的体外模拟表明，某些神经元G蛋白偶联受体(GPCRs)的激活，如趋化因子受体，可以通过调节细胞生存信号通路来对抗兴奋性毒性神经元损伤。APJ受体是最近被描述的一种GPCR，与趋化因子受体一样，可以作为HIV进入某些细胞的辅助受体。此外，APJ及其配体apelin在中枢神经系统(CNS)中高度表达，提示Apelin/APJ信号可能在调节中枢神经系统对HIV诱导的神经毒性的反应中发挥核心作用。我们的初步研究表明，炎症和/或NMDAR介导的神经元激活后apelin的释放通过激活细胞生存激酶来抵消HIV诱导的神经毒性。基于这些发现，我们假设apelin作为一种通过APJ的可溶性神经肽，在HIV感染期间通过炎症和/或NMDAR介导的神经元激活之后，激活了一种新的内源性神经元生存反应，该反应整合了几个细胞生存信号通路。因此，在这项建议中，我们将确定APELIN介导的神经保护的机制(S)。具体目标1将使用ELISA和基于抗体的微阵列来定义由apelin/APJ相互作用调节的细胞生存信号通路。具体目标2将确定apelin功能阻断抗体，并使用ELISA、聚合酶链式反应和免疫荧光神经毒性试验来确定在HIV诱导的神经毒性过程中apelin表达和释放的功能变化。具体目标3将使用钙成像和Western blotting来确定apelin在调节NMDAR介导的兴奋性毒性细胞信号中的潜在作用。公共卫生相关性：兴奋毒性神经元损伤与多种神经退行性疾病有关，包括缺氧/缺血、癫痫、亨廷顿病、帕金森病、阿尔茨海默病和艾滋病毒相关神经认知障碍(手)。通过提高我们对促进神经元存活的信号转导途径的了解，我们希望提高我们开发治疗手部和相关神经退行性疾病的药物的能力。

DESCRIPTION (provided by applicant): Excitotoxic neuronal injury via activation of the N-methyl-D-aspartate receptor (NMDAR) has been implicated in a variety of neurodegenerative disorders, including human immunodeficiency virus (HIV)-associated neurocognitive disorders (IHAND). The broad objective of this proposal is to improve our understanding of signaling pathways that promote neuronal survival against HIV-induced neurotoxicity, thereby enhancing our ability to develop therapeutics for HAND and related neurodegenerative disorders. In vitro modeling of HIV-induced neurotoxicity demonstrates that activation of certain neuronal G-protein coupled receptors (GPCRs), such as chemokine receptors, can counteract excitotoxic neuronal injury through modulation of cell survival signaling pathways. The APJ receptor is a recently described GPCR that, like chemokine receptors, can serve as a co-receptor for HIV entry in certain cells. Furthermore, APJ and its ligand apelin are highly expressed in the central nervous system (CNS), suggesting that apelin/APJ signaling could play a central role in modulating CNS responses to HIV-induced neurotoxicity. Our preliminary investigations suggest that apelin release following inflammatory- and/or NMDAR-mediated neuronal activation counteracts HIV-induced neurotoxicity via activation of cell survival kinases. Based on these findings, we hypothesize that apelin, acting as a soluble neuropeptide through APJ, activates a novel, endogenous neuronal survival response that integrates several cell survival signaling pathways following inflammatory- and/or NMDAR-mediated neuronal activation during HIV infection. Therefore, in this proposal, we will determine the mechanism(s) of apelin-mediated neuroprotection. Specific Aim 1 will use ELISAs and an antibody-based microarray to define the cell survival signaling pathways modulated by apelin/APJ interactions. Specific Aim 2 will identify an apelin function blocking antibody and use ELISAs, PCR, and an immunofluorescent neurotoxicity assay to identify functional changes in apelin expression and release during HIV-induced neurotoxicity. Specific Aim 3 will use calcium imaging and Western blotting to identify potential roles for apelin in modulating NMDAR-mediated excitotoxic cell signaling. PUBLIC HEALTH RELEVANCE: Excitotoxic neuronal injury has been implicated in a variety of neurodegenerative disorders, including hypoxia/ischemia, epilepsy, Huntington's Disease, Parkinson's Disease, Alzheimer's Disease, and HIV-associated neurocognitive disorders (HAND). By improving our understanding of signal transduction pathways that promote neuronal survival against HIV-induced toxicity, we hope to enhance our ability to develop therapeutics for HAND and related neurodegenerative disorders.