Chloride channel-dependent mechanisms of opiate and HIV-induced synaptodendritic injury

感染HIV-1(PWH)患者的阿片类药物使用障碍(OUD)加剧了神经HIV和 HIV相关神经认知障碍(手)通过涉及直接外周的复杂机制(例如， 免疫抑制)和中枢神经系统(如神经炎、血脑屏障损伤和神经元损伤) 效果。虽然谷氨酸能兴奋毒性仍然是HIV依赖性神经元损伤的主要驱动力， 来自我们实验室的新证据表明，失去抑制性GABA能控制和[Cl−]i稳态 不仅有助于失去抑制，而且还增加了谷氨酸的兴奋/神经毒性作用 NMDA和AMPA受体。这一建议直接检验了假设[Cl−]i依赖于净亏损 神经元抑制会增加兴奋性，促进兴奋性毒性。在成熟神经元中，细胞内的Cl− 浓度([Cl−]i)由膜离子通道(GAAA和甘氨酸受体)动态调节，并 CL−通道和转运体。通过控制[Cl−]i，这些通道和转运体调节Cl− 平衡电位(ECL)和神经元抑制，我们已经展示了KCC2功能丧失在 OUD/神经HIV模型导致[Cl−]i升高，ECL升高，并具有兴奋性毒性。我们发现了一个以前的 一种未知的ClC-1样电压依赖性氯−通道，对多巴胺的兴奋性有不同的调节作用 纹状体中棘神经元(MSN)和IS分别表达受体D_1和D_2 被阿片类药物和HIV TAT扰乱。我们假设阿片类药物和HIV-1破坏了[Cl−]i，通过 电压门控性ClC CL−通道导致突触树突起损伤。这一假设将在 遵循特定的目标，如果得到证实，将是我们对阿片类药物和艾滋病毒如何 会导致兴奋性毒性。目标1将确定阿片类药物和艾滋病毒失调电压的机制- 依赖ClC-1通道与体外Cl-−动态平衡我们的初步研究结果表明，ClC-1 显著影响D1MSN和D2MSN的电压依赖的CL−电流。ClC-1在多大程度上调节 艾滋病毒和阿片类药物诱导的病理将使用功能获得、功能丧失和 在体外和体内/体外使用电生理学、药理学和遗传学方法在 细胞和分子水平。目的2.确定ClC-1在多大程度上对突触树突起起作用 阿片类药物损伤和HIV诱导的Cl-−动态平衡失调我们预测，监管失衡 在OUD/神经HIV模型中，[Cl−]i的动态平衡放大MSN中的突触树突触损伤。由于CLC-1可以是 活性依赖的Cl-−进入的新来源，我们还预测阿片类药物和HIVTat通过 一种复杂的机制，涉及ClC-1的调节，从而导致突触去抑制。该项目将测试 阿片类药物和艾滋病病毒是否通过ClC-1调节[ClClC]i动态平衡并导致神经元损伤。如果CLC-1是 被确认为该目标，正如初步证据表明，这将是我们 了解阿片类药物和艾滋病毒如何导致兴奋性毒性。

Opioid use disorder (OUD) in people infected with HIV-1 (PWH) exacerbates the pathobiology of neuroHIV and HIV-associated neurocognitive disorder (HAND) via complex mechanisms involving direct peripheral (e.g., immune suppression) and CNS (e.g., neuroinflammation, blood-brain barrier damage, and neuronal injury) effects. Although glutamatergic excitotoxicity remains the major driving force in HIV-dependent neuronal injury, emerging evidence from our lab indicates that the loss of inhibitory GABAergic control and [Cl−]i homeostasis not only contributes to a loss of inhibition, but also increases the excitatory/neurotoxic effects of glutamate at NMDA and AMPA receptors. This proposal directly tests the assumption that [Cl−]i-dependent net losses of neuronal inhibition will increase excitation and promote excitotoxic. In mature neurons, intracellular Cl− concentration ([Cl−]i) is dynamically regulated by membrane ion channels (GABAA and glycine receptors) and Cl− channels and transporters. By controlling [Cl−]i, these channels and transporters regulate the Cl− equilibrium potential (ECl) and neuronal inhibition and we have already shown the KCC2 loss-of-function in OUD/neuroHIV models leads to [Cl−]i increases, elevated ECl, and excitotoxicity. We discovered a previously unidentified a ClC-1-like voltage-dependent Cl− channel that differentially regulates the excitability of dopamine receptor D1- and D2- expressing (D1 and D2, respectively) striatal medium spiny neurons (MSNs) and is disrupted by opioids and HIV Tat. We hypothesize that opioids and HIV-1 disrupt [Cl−]i, homeostasis via a voltage-gated ClC Cl− channel resulting in synaptodendritic injury. This hypothesis will be tested in the following specific aims and if confirmed will be a conceptual shift in our understanding of how opioids and HIV contribute to excitotoxicity. Aim 1 will identify the mechanisms by which opioids and HIV dysregulate voltage- dependent ClC-1 channels and Cl− homeostasis in vitro. Our preliminary findings suggest that ClC-1 significantly affects voltage-dependent Cl− currents in D1 and D2 MSNs. The extent to which ClC-1 mediates the HIV and opioid-induced pathology will be explored using gain-of-function, loss-of-function strategies, and confirmed in vitro and in vivo/ex vivo using electrophysiologic, pharmacologic, and genetic approaches at the cell and molecular levels. Aim 2. Establish to what extent ClC-1 modulation contributes to the synaptodendritic injury caused by opioids and HIV-induced dysregulation of Cl− homeostasis. We predict that the dysregulation of [Cl−]i homeostasis amplifies synaptodendritic injury in MSNs in OUD/neuroHIV models. Since ClC-1 can be a novel source of activity-dependent Cl− entry, we also predict that opioids and HIV Tat cause neuronal injury via a complex mechanism involving ClC-1 modulation and, thus, synaptic disinhibition. This project will test whether opioids and HIV dysregulate [Cl−]i homeostasis and cause neuronal injury via ClC-1. If ClC-1 is confirmed to be that target, as preliminary evidence indicates, this will be a conceptual shift in our understanding of how opioids and HIV contribute to excitotoxicity.