The Role of Presenilins in HIV Associated Dementia

描述(由申请人提供)：艾滋病毒相关性痴呆(HAD)是一个重要的和潜在的可治疗的认知能力下降的原因。尽管随着高效抗逆转录病毒疗法(HAART)的出现，艾滋病死亡率有所提高，但HAD的患病率正在上升。对HAD和阿尔茨海默病(AD)等其他神经退行性疾病患者脑组织的神经病理学研究显示，有证据表明存在显著的神经炎性变化，包括常驻大脑免疫细胞的小胶质细胞的激活。早老素蛋白(PS)、早老素1(PS1)和早老素2(PS2)基因突变导致家族性AD，因此PS是神经退行性疾病研究的自然热点。PS是Y-分泌酶复合体的催化成分，Y-分泌酶复合体是一种膜蛋白酶，可以处理淀粉样多肽蛋白形成淀粉样β蛋白，发现于AD斑块中。PS-y-分泌酶复合体还裂解许多与炎症过程有关的底物，如ErbB4、Notch、p75。以前的工作表明PS在中枢神经系统炎症中起作用，我们的初步数据表明，在HIV外壳蛋白gp120刺激的HAD脑和小胶质细胞中，PS2蛋白增加。在这份K08职业发展建议中，我们假设PS是HAD神经炎症过程中不可或缺的一部分。在获奖期间，研究人员将研究由HIV外壳蛋白gp120激活的小胶质细胞中药理上的y-分泌酶抑制和PS的shRNA击倒的效果。来自PS2基因敲除小鼠的原代小胶质细胞将被检测gp120诱导的激活。利用免疫组织化学方法，我们将研究与小胶质细胞炎症反应有关的两种Y-分泌酶底物ErbB4和p75NTR在HAD脑内的细胞类型和亚细胞表达。我们将使用免疫共沉淀法确定已知的y-分泌酶组件是否在小胶质细胞中组装，并测量小胶质细胞y-分泌酶对炎症刺激的反应活性。已知PS可独立于γ-分泌酶复合体调节细胞功能，因此我们将利用蛋白质组学技术在静止和gp120刺激的小胶质细胞中鉴定新的PS结合伙伴。多学科方法将提供必要的培训环境，促进这位年轻的研究人员发展成为一名独立的临床医生-科学家。HAD对个人、家庭和医疗保健系统来说是一个代价高昂的负担。这一建议将有助于从根本上理解艾滋病毒引起的神经炎症的机制，这可能会导致治疗HAD的更有效的疗法。

DESCRIPTION (provided by applicant): HIV associated dementia (HAD) is a significant and potentially treatable cause of cognitive decline. Despite improved AIDS mortality rates with the advent of highly active anti-retroviral therapy (HAART), the prevalence of HAD is increasing. Neuropathological studies of brain tissue from patients with HAD and other neurodegenerative diseases such as Alzheimer's disease (AD), reveal evidence of prominent neuroinflammatory changes including activation of microglia, the resident brain immune cells. Mutations in the genes coding for the presenilin proteins (PS), presenilin 1 (PS1) and presenilin 2 (PS2) cause familial AD, and thus PS are a natural focus of study in neurodegenerative disease. PS are the catalytic component of the y-secretase complex, a membrane protease that processes amyloid peptide protein to form amyloid beta peptide, found in AD plaques. The PS y-secretase complex also cleaves numerous substrates such as ErbB4, Notch, p75 that have been implicated in inflammatory processes. Previous work suggests a role for PS in central nervous system inflammation and our preliminary data demonstrate that PS2 protein is increased in HAD brain as well as in microglia stimulated by the HIV coat protein, gp120. In this K08 career development proposal, we hypothesize that PS are integral to the neuroinflammatory processes in HAD. During the award period the investigator will study the effects of pharmacological y-secretase inhibition and shRNA knock down of PS in microglia activated by the HIV coat protein, gp120. Primary microglia from PS2 knockout mice will be assayed for gp120 induced activation. Using immunohistochemistry we will investigate cell type and sub-cellular expression in HAD brain of two Y-secretase substrates implicated in the microglia inflammatory response, ErbB4 and p75NTR. We will determine if the known y-secretase components assemble in microglia using co-immunoprecipitation and measure microglia y-secretase activity in response to inflammatory stimuli. PS are known to mediate cellular functions independent of the y-secretase complex, and therefore we will employ proteomic techniques to identify novel PS binding partners in quiescent and gp120 stimulated microglia. A multidisciplinary approach including mentored bench research, didactics, seminars and professional conferences will provide the necessary training environment to promote the development of this young investigator into an independent clinician-scientist. HAD is a costly burden to individuals, families and the health care system. This proposal will contribute to the fundamental understanding of mechanisms in HIV induced neuroinflammation that will potentially lead to more effective therapeutics in the treatment of HAD.