COMPLEMENT MECHANISMS IN AMYLOID BETA PEPTIDE CLEARANCE

描述(申请人提供)：炎症是破坏性和重建性力量的混合体，两者的平衡决定了有机体的整体效用或损失。通过了解哪些炎症机制在阿尔茨海默病(AD)中是有用的，哪些是有害的，我们可能会得出更好的治疗这种疾病的方法。我们先前在目前RO1下的AD炎症研究强调了毒性机制。在这里，我们集中在AD炎症的潜在有益机制，淀粉样β蛋白(Abeta)的补体调理，以及它如何在中枢神经系统和Abeta的外周加工中发挥关键作用。特定目的1将利用AD小胶质细胞的培养来研究补充机制在清除脑Abeta中的作用，并将过表达Happ的转基因小鼠与C3基因敲除小鼠杂交，以评估这些机制在体内的操作。我们将展示补体调理素和过敏性毒素有助于推动小胶质细胞对Abeta的趋化和吞噬，并且在缺乏它们的情况下，大脑中Abeta的积聚增加。由于补体调理是抗体介导的抗原清除的正常特征，该研究还将研究补体与Abeta免疫的相互作用。特殊目标2将把研究结果扩展到外周Abeta清除。最近的研究表明，外周存在Abeta池，并且抗Abeta抗体不能实质性地穿透脑隔离物或清除循环中的Abeta，导致脑Abeta沉积减少。那么关键的问题就变成了，Abeta会发生什么？补体清除循环免疫复合体的机制是众所周知的，我们希望证明它们在外周Abeta清除方面是有效的。Happ过表达与C3基因敲除小鼠的杂交应该显示出外周和中枢神经系统在清除Abeta方面的缺陷。在我们的小鼠模型中，由于缺乏补体机制而导致的Aβ积聚可能会导致神经退行性变的加剧。或者，抑制补体溶解机制可能具有神经保护作用。我们将比较外周补体和Abeta指标与神经退行性变的指标，以评估总的来说，补体机制在AD中最终是否更有帮助而不是更有害。这些研究还将检查补体缺乏与Abeta免疫的相互作用，这可能会导致免疫复合物沉积问题，这可能与当前的临床试验有关。

DESCRIPTION (provided by applicant): Inflammation is a mixture of destructive and rebuilding forces, the balance of which dictates the overall utility or loss to the organism. By understanding which inflammatory mechanisms are useful in Alzheimer's disease (AD) and which are detrimental, we may arrive at better ways of treating the disorder. Our previous AD inflammation research under the present RO1 has emphasized toxicity mechanisms. Here, we focus on a potentially beneficial mechanism of AD inflammation, complement opsonization of amyloid beta peptide (Abeta), and how it may play a critical role in both CNS and peripheral processing of Abeta. Specific Aim 1 will use cultures of AD microglia to investigate complement mechanisms in the clearance of brain Abeta, and hAPP overexpressing transgenic mice crossed with C3-knockout mice to evaluate the operation of those mechanisms in vivo. We will show that complement opsonins and anaphylatoxins help drive microglial chemotaxis to and phagocytosis of Abeta, and that, in their absence, brain accumulation of Abeta increases. Since complement opsonization is a normal feature of antibody-mediated clearance of antigens, the studies will also investigate complement interactions with Abeta immunization. Specific Aim 2 will extend the findings to peripheral Abeta clearance. Recent studies have shown that peripheral pools of Abeta exist, and that an anti-Abeta antibody that does not materially penetrate the brain sequesters or removes circulating Abeta, resulting in decreased brain Abeta deposition. The critical question then becomes, what happens to the Abeta? Complement mechanisms in clearance of circulating immune complexes are well known, and we expect to demonstrate that they are operative in the context of peripheral Abeta clearance. Crosses of hAPP-overexpressing with C3- knockout mice should show peripheral as well as CNS deficits in Abeta removal. Abeta accumulation due to deficient complement mechanisms could engender enhanced neurodegeneration in our mouse model. Alternatively, the inhibition of complement lytic mechanisms could be neuroprotective. We will compare peripheral complement and Abeta measures with measures of neurodegeneration to evaluate whether, on balance, complement mechanisms are ultimately more helpful than harmful in AD. The studies will also examine interactions of complement deficiency with Abeta immunization, which could cause immune complex deposition problems that may be relevant to current clinical trials.