The role of novel endolysosome-dependent calcium regulatory mechanisms in HIV-1 T

描述(申请人提供)：联合抗逆转录病毒疗法显著延长了HIV-1感染者的寿命，但HIV-1的破坏性影响持续存在于整个神经系统，在美国HIV-1感染者中，HIV-1相关神经认知障碍(HAND)的患病率超过50%。我们的长期目标是了解手部疾病的发病机制，并开发治疗干预措施。这些研究集中于确定HIV-1反式转录激活蛋白(HIV-1 Tat)促进手部发育的新的内溶酶体依赖机制。我们的中心假设是，HIV-1Tat通过升高内溶酶体的pH并激活一种新的内溶酶体依赖的钙调节机制来诱导突触破坏和神经元损伤。在我们的初步发现的指导下，这一新的假设将通过追求三个具体目标来检验。(1)在体外确定HIV-1 TAT激活 新的内溶酶体依赖性钙调节机制。(2)体外测定上述内溶酶体依赖性钙调节机制在HIV-1Tat诱导的神经元损伤中的作用。(3)在体内确定上述内溶酶体机制在多大程度上破坏了HIV-1Tat转基因小鼠的突触完整性。我们的结果有望证明内溶酶体在HIV-1TAT诱导的突触破坏和神经细胞死亡中发挥关键作用，这是通过一种新的内溶酶体依赖的钙调节机制来实现的，该机制是先前描述的HIV-1TAT效应的上游。这些结果有望将导致手部早期病理特征的统一机制联系在一起。这项工作的结果将有助于更好地理解手部的发病机制，并可能开发新的治疗方法。

DESCRIPTION (provided by applicant): Combined antiretroviral therapy has increased dramatically the life span of HIV-1 infected individuals, but damaging effects of HIV-1 persist throughout the nervous system, and the prevalence of HIV-1 associated neurocognitive disorder (HAND) is greater than 50% of HIV-1 infected people in the USA. Our long-term goal is to understand the pathogenesis of HAND and develop therapeutic interventions. The proposed studies are focused to determine the novel endolysosome-dependent mechanisms whereby HIV-1 transactivator of transcription protein (HIV-1 Tat) contributes to the development of HAND. Our central hypothesis is that HIV-1 Tat induces synaptic disruption and neuronal injury by elevating endolysosome pH and activating a novel endolysosome-dependent calcium regulatory mechanism. Guided by our preliminary findings, this novel hypothesis will be tested by pursuing three specific aims. (1) Determine, in vitro, the extent to which HIV-1 Tat activates a novel endolysosome-dependent calcium regulatory mechanism. (2) Determine, in vitro, the extent to which the above endolysosome-dependent calcium regulatory mechanism underlies HIV-1 Tat-induced neuronal injury. (3) Determine, in vivo, the extent to which the above endolysosome mechanism contributes to disrupted synaptic integrity in HIV-1 Tat transgenic mice. Our results are expected to demonstrate that endolysosomes play a critical role in HIV-1 Tat-induced synaptic disruption and neuronal cell death through a novel endolysosome-dependent calcium regulatory mechanism that is upstream of previously described effects of HIV-1 Tat. Such results are expected to link together unified mechanisms causing early pathological features of HAND. Results from this work will lead to a greater understanding of HAND pathogenesis and the possible development of new therapeutics.