The Role of Presenilins in HIV Associated Dementia

描述（由申请人提供）：HIV相关性痴呆（HAD）是认知能力下降的一个重要和潜在的可治疗原因。尽管随着高效抗逆转录病毒疗法（HAART）的出现，艾滋病死亡率有所下降，但HAD的流行率仍在上升。对患有HAD和其他神经退行性疾病（如阿尔茨海默病（AD））的患者的脑组织的神经病理学研究揭示了显著的神经炎性变化的证据，包括小胶质细胞（常驻脑免疫细胞）的激活。早老素蛋白（PS）、早老素1（PS1）和早老素2（PS2）的基因编码突变导致家族性AD，因此PS是神经退行性疾病研究的自然焦点。PS是γ-分泌酶复合物的催化组分，γ-分泌酶复合物是一种膜蛋白酶，其加工淀粉样肽蛋白以形成淀粉样β肽，在AD斑块中发现。PS γ-分泌酶复合物还切割许多底物，如ErbB 4、Notch、p75，这些底物与炎症过程有关。以前的工作表明PS在中枢神经系统炎症中的作用，我们的初步数据表明，PS2蛋白在HAD脑中以及在HIV外壳蛋白gp 120刺激的小胶质细胞中增加。在这个K 08职业发展建议中，我们假设PS是HAD神经炎症过程的组成部分。在授予期间，研究者将研究药理学γ-分泌酶抑制和PS的shRNA敲低在由HIV外壳蛋白gp 120激活的小胶质细胞中的作用。将测定来自PS2敲除小鼠的原代小胶质细胞的gp 120诱导的活化。使用免疫组化，我们将调查细胞类型和亚细胞表达HAD脑中的两个Y-分泌酶底物牵连的小胶质细胞炎症反应，ErbB 4和p75 NTR。我们将确定是否已知的γ-分泌酶组件组装在小胶质细胞使用免疫共沉淀和测量小胶质细胞γ-分泌酶活性的炎症刺激。已知PS介导的细胞功能独立的γ-分泌酶复合物，因此，我们将采用蛋白质组学技术，以确定新的PS结合伙伴在静止和gp 120刺激的小胶质细胞。一个多学科的方法，包括指导实验室研究，教学法，研讨会和专业会议将提供必要的培训环境，以促进这一年轻的研究人员发展成为一个独立的临床医生，科学家。HAD对个人、家庭和医疗系统来说都是一个昂贵的负担。这一建议将有助于从根本上了解艾滋病毒诱导的神经炎症机制，这将可能导致更有效的治疗HAD的治疗。

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.