Threshold of Cognitive Impairment after HIV Infection: Effect of Morphine

描述（由申请人提供）：目前，抗逆转录病毒疗法可以保护或恢复HIV感染者的免疫功能，但其中约50%的人死于轻度亚痴呆形式的HAND，这些HAND在很大程度上难以治疗。我们提出了创新的研究来测试新的假设，即在病毒传播后早期发生HAND的致病过程，尽管后来对病毒进行了抗病毒或免疫控制，但它们仍然存在，并且它们可能因阿片类药物的使用而加剧。这一假设的可检验的翻译含义是，针对早期神经发病机制的关键决定因素的治疗可以预防HAND。该假设将在已建立的HIV感染和免疫活性小鼠接种嗜鼠性HIV（EcoHIV）的早期认知障碍系统中进行测试。这些小鼠认知疾病的自然史与HIV感染者的轻度HAND密切相关。HIV在全身感染后5天内进入小鼠大脑，4-5周后出现认知障碍，尽管有适应性抗病毒免疫和病毒抑制，但仍持续存在。脑病理学正常，但认知功能障碍与突触可塑性基因（包括CaMKII和SYN 2）的抑制相关;染色质免疫沉淀法测定，这两种基因的启动子上的组蛋白3也具有基因沉默表观遗传修饰，表明HAND中某些突触功能的稳定破坏。慢性吗啡暴露和艾滋病毒协同作用导致小鼠认知障碍。我们推测，小鼠感染后不久，在建立适应性免疫反应之前，脑损伤在很大程度上是不可逆的，并启动了导致认知障碍的神经致病程序。本申请的总体目标是测试这一命题，探索所涉及的选定机制，并将研究结果应用于确定预防HAND的疗法。目标是：1）确定亚临床HAND的病毒学和突触决定因素及其向临床疾病的进展; 2）确定吗啡在亚临床和临床HAND中的作用; 3）通过染色质重塑和达特的潜在作用来测试小鼠HAND中突触可塑性基因的泛失调的新机制; 4）探索干扰临床前HAND以防止向临床疾病的进展的干预措施。我们相信，使用认知障碍作为相关疾病的读出，结合小鼠实验的多功能性，将有助于识别参与HAND的关键生理和分子过程。研究将仅在小鼠中进行，包括常规和特异性敲除品系，主要通过EcoHIV全身感染，通过植入定时释放颗粒进行慢性吗啡治疗/不进行慢性吗啡治疗。在小鼠中鉴定的选定疾病标志物将在按阿片类药物分层的MND患者的存档脑组织中得到证实 成瘾定时干预将包括染色质重塑抑制剂。

DESCRIPTION (provided by applicant): Presently antiretroviral therapies can preserve or restore immune function in HIV-infected people, but roughly 50% of them succumb to mild sub-dementia forms of HAND that are largely refractory to treatment. We propose innovative research to test the new hypothesis that the pathogenic processes responsible for HAND ensue early after virus transmission, they persist despite later antiviral or immune control of virus, an they may be exacerbated by opiate use. The testable translational implication of this hypothesis is that therapies targeting key determinants of the early neuropathogenesis may prevent HAND. The hypothesis will be tested in an established system of HIV infection and early cognitive impairment in immunocompetent mice inoculated with mouse-tropic HIV, EcoHIV. The natural history of cognitive disease in these mice closely models mild HAND in HIV-infected humans. HIV enters the mouse brain within 5 days of systemic infection with cognitive impairments developing 4-5 weeks later and persisting despite adaptive antiviral immunity and virus suppression. Brain pathology was normal but cognitive dysfunction correlated with suppression of synaptic plasticity genes including CaMKII and SYN2; both genes also had gene-silencing epigenetic modifications of histone 3 on their promoters as determined by chromatin immunoprecipitation, suggesting stable disruption of some synaptic functions in HAND. Chronic morphine exposure and HIV synergized in causing cognitive impairment in mice. We postulate that the brain injury inflicted soon after infection of mice, before establishment of adaptive immune responses, is largely irreversible and initiates a neuropathogenic program leading to cognitive impairment. The overall goals of this application are to test this proposition, explore selected mechanisms involved, and apply the findings to identify therapies to prevent HAND. The Aims are: 1) To define virological and synaptic determinants of subclinical HAND and its progression to clinical disease; 2) To determine morphine effects in subclinical and clinical HAND; 3) To test a novel mechanism of pan- dysregulation of synaptic plasticity genes in murine HAND by chromatin remodeling and the potential role of Tat; 4) To explore interventions disrupting preclinical HAND to prevent progression to clinical disease. We believe that use of cognitive impairment as a relevant disease readout, combined with versatility of mouse experimentation, will facilitate identification of key physiological and molecular processes involved in HAND. Studies will be conducted exclusively in mice, both conventional and specific knock-out strains, principally through systemic infection with EcoHIV, with/without chronic morphine treatment through implantation of timed- release pellets. Selected disease markers identified in mice will be confirmed in archival brain tissues of MND patients stratified by opiate addiction. Timed interventions will include inhibitors of chromatin remodeling.