HIV-1 NEUROTOXICITY--MECHANISM AND MODULATION BY OPIOIDS

HIV-1包膜蛋白gp 120是一种有效的神经毒素， 突触网络中的神经元能活动的异常模式， 在大鼠海马神经元的原代培养物中形成。HIV-1释放的gpl 20 受感染的细胞可能会导致神经损伤， 经常伴随艾滋病。不同的嗜神经性差异 人类HIV-1病毒株及gp 12 O的神经毒性观察 在啮齿类动物模型中，表明 神经毒性与感染所需的毒性不同。的 引起神经毒性所需的gp 120的结构元件将 测定HeLa细胞将用各种菌株和突变体转染 gp 120基因，并与大鼠海马神经元共培养，以评估 释放的GP 120的神经毒性。已经开发了一个模型来测试 假设突触活动的特定模式导致 神经毒性因此，异常的电活动模式将被 用膜片钳技术记录并与神经元活力相关。 该兴奋性毒性模型提供了适合于评价神经毒性的测定法。 滥用药物对神经元能突触传递的影响， 神经毒性初步研究结果表明，大麻素可以减少这种情况。 突触活动将评估该传感器作为潜在的 谷氨酸诱导钙负荷的靶点。海马神经元会 用线粒体定向的脱辅基水母发光蛋白基因转染。钙 水母发光蛋白的依赖性发光将用于特异性测量 线粒体钙浓度线粒体损伤在 将探索谷氨酸诱导的细胞死亡。在感觉神经元中， 抗HIV药物双脱氧胞苷（ddC）减少线粒体DNA（mtDNA） 并改变钙缓冲。这一观察可能与 周围神经病变是使用ddC治疗的限制性副作用， 艾滋病的治疗。一系列新型核苷类似物将被测试 对大鼠线粒体DNA含量的影响和对钙缓冲的影响 感觉神经元这些研究可以鉴定出具有抗HIV的化合物 没有表现出神经性副作用的活性。这项建议 描述了实验，将提供更好的理解 gp 120诱导神经毒性的机制。分子定义 gp 120的神经毒性特征将有助于在CNN中识别其靶标。的 gp 120在突触网络上的作用将决定 神经毒性的电生理机制和突触效应 滥用和潜在的神经保护药物。细胞研究将 直接寻址，作为谷氨酸的潜在目标， 和核苷诱导的神经元死亡。

The HIV-1 envelope protein, gpl20, is a potent neurotoxin that evokes an aberrant pattern of glutamatergic activity in the synaptic network that forms in primary cultures of rat hippocampal neurons. gpl20 shed by HIV-l infected cells may contribute to the neurological impairment that frequently accompanies AIDS. Differences in the neurotropism of various HIV-1 strains in man and the observation that gpl2O elicits neurotoxicity in rodent models, suggest that the structural requirements for neurotoxicity are distinct from those required for infection. The structural elements of gp120 required to elicit neurotoxicity will be determined. HeLa cells will be transfected with various strain and mutant gpl20 genes and co-cultured with rat hippocampal neurons to assess the neurotoxicity of released gpl20. A model has been developed to test the hypothesis that specific patterns of synaptic activity result in neurotoxicity. Thus, aberrant patterns of electrical activity will be recorded with the patch-clamp technique and related to neuronal viability. This excitotoxicity model provides an assay suitable for evaluating the effects of drugs of abuse on glutamatergic synaptic transmission and neurotoxicity. Preliminary findings indicate that cannabinoids reduce this synaptic activity. The mitochondrion will be evaluated as a potential target for glutamate-induced calcium loads. Hippocampal neurons will be transfected with a mitochondrial directed apoaequorin gene. The calcium dependent luminescence of aequorin will be used to specifically measure mitochondrial calcium concentration. The role of mitochondrial damage in glutamate-induced cell death will be explored. In sensory neurons, the anti-HIV drug dideoxycytidine (ddC) decreases mitochondrial DNA (mtDNA) and alters calcium buffering. This observation may be relevant to the peripheral neuropathy that is a limiting side effect in the use of ddC for the treatment of AIDS. A series of novel nucleoside analogs will be tested for effects on mtDNA content and effects on calcium buffering in rat sensory neurons. These studies may identify compounds with anti-HlV activity that fail to exhibit neuropathic side effects. This proposal describes experiments that will provide a better understanding of the mechanism of gpl20-induced neurotoxicity. Molecular definition of the neurotoxic features of gpl20 will help identify its target in the CNN. The actions of gp120 on the synaptic network will determine the electrophysiological mechanism of neurotoxicity and the synaptic effects of abused and potentially neuroprotective drugs. Cellular studies will address directly, the mitochondrion as a potential target for glutamate and nucleoside-induced neuronal death.