RAGE-Proteolyzing Antibodies for Alzheimer's Disease Therapy

描述(由申请人提供)：激活血脑屏障(BBB)内皮、神经元和小胶质细胞上的全长、膜结合的晚期糖基化终产物受体(FlRAGE)亚型，通过增加脑组织中β-淀粉样蛋白(2)的积聚，增加炎症和氧化应激，促进阿尔茨海默病(AD)的发生和发展。尽管通过拮抗FRAGE与其多个配体的结合来防止FRAGE的激活是一种有吸引力的治疗策略，但毒性、低疗效和较差的BBB渗透性使RAGE靶向治疗试验仅限于一个小分子，甚至这种单独的候选药物也会产生副作用。我们将开发蛋白水解性抗体(CatAbbs)，能够使每个CatAb灭活数千个flrage分子，作为一种新的“催化优势”疗法，有可能成为AD的第一个有效的疾病修改治疗方法。一个酵母表面展示平台，以前用于开发抗原结合抗体(BindAbbs)来治疗一系列疾病，将被用来创造催化flRAGE特异性水解的人CatAbs。FRAGE CatAbs能够催化数千个循环的短命FRAGE结合、FRAGE水解、产物释放以及与另一FRAGE分子的相互作用，这给了CatAbs许多优于FRAGE结合药物的“催化优势”。CatAbbs的特异性和高剂量疗效减少了上面FRAGE拮抗剂试验中看到的副作用的机会。此外，CatAbbs将结合抗体的特异性与每个抗体更多的灭活靶标结合在一起，这是一个关键的好处，因为BBB对蛋白质药物的渗透性很低。此外，CatAbbs对flge分子的快速水解和释放将使给药后表达的flRAGE靶标失活，使CatAbbs具有独特的能力来解释flRAGE的周转。最后，与FRAGE拮抗剂不同，CatAbbs不会与FRAGE的循环亚型SRAGE发生长期结合，因此不太可能阻碍SRAGE促进的抗体从血浆中清除。我们将使用一种新的文库设计方法来构建一个酵母展示的CatAb文库，该文库将作为多种FlRAGE CatAb的来源。荧光激活细胞分选(FACS)将使铅FRAGE CatAb的分离和随后的CatAb工程得以增强催化性能。表达在小鼠细胞膜上的FRAGE的CatAb水解性将在体外得到验证。这项工作将导致与Sun Health Research Institute神经炎症实验室(太阳城，亚利桑那州)合作进行的后续CatAb工程和AD小鼠模型研究的建议。我们对这些首次“催化优势”的AD疗法的潜在影响感到兴奋，并渴望启动这项研究。 与公共卫生相关：目前还没有令人满意的有效治疗阿尔茨海默病(AD)的方法。阿尔茨海默病是一种折磨着超过450万美国人的疾病，每年产生的经济影响超过1000亿美元。尽管已知晚期糖基化终产物受体(RAGE)在AD发生和发展的多个方面发挥作用，但针对这种不良蛋白的靶向治疗的挑战导致临床试验中只有一种RAGE靶向治疗得到评估。我们将开发一种新的RAGE靶向疗法，能够在每个单一治疗分子中摧毁数千份RAGE蛋白，并具有成为第一个真正有效的AD疗法的令人兴奋的潜力。

DESCRIPTION (provided by applicant): Activation of the full length, membrane bound isoform of the Receptor for Advanced Glycation End Products (flRAGE) on blood brain barrier (BBB) endothelium, neurons and microglia promotes the onset and progression of Alzheimer's Disease (AD) by increasing accumulation of beta-amyloid ( 2) in brain tissue, raising inflammation and elevating oxidative stress. Although preventing activation of flRAGE by antagonizing binding to its many ligands is an attractive AD treatment strategy, toxicity, low efficacy and poor BBB penetration have limited RAGE-targeted therapeutic testing to one small molecule and even this lone drug candidate caused side effects. Wewill develop proteolytic antibodies (CatAbs), able to inactivate thousands of flRAGE molecules per CatAb, as a new class of "catalytically advantaged" therapeutics with the potential to serve as the first effective disease-modifying treatments for AD. A yeast surface display platform, previously used to develop antigen-binding Abs (BindAbs) to treat a range of diseases, will be employed to create human CatAbs catalyzing specific hydrolysis of flRAGE. flRAGE CatAbs' ability to catalyze thousands of cycles of short-lived flRAGE binding, flRAGE hydrolysis, product release and interaction with another flRAGE molecule give CatAbs many "catalytic advantages" over flRAGE-binding drugs. CatAbs' specificity and high dose efficacy reduces the chances of side effects as seen in the flRAGE antagonist trial above. Also, CatAbs pair BindAbs' specificity with a much higher number of targets inactivated per Ab, a key benefit given the BBB's low permeability to protein drugs. Furthermore, CatAbs' rapid hydrolysis and release of flRAGE molecules will allow inactivation of flRAGE targets expressed after drug administration, giving CatAbs a unique ability to account for flRAGE turnover. Finally, unlike flRAGE antagonists, CatAbs will not undergo long-lived binding to flRAGE's circulating isoform, sRAGE, and thus be unlikely to impede sRAGE-promoted clearance of Ab from plasma. We will use a novel library design approach to construct a yeast-displayed CatAb library that will serve as a source of multiple flRAGE CatAbs. Fluorescence Activated Cell Sorting (FACS) will enable both isolation of lead flRAGE CatAbs and subsequent CatAb engineering for enhanced catalytic properties. CatAb hydrolysis of flRAGE expressed on murine cell membranes will be validated in vitro. This work will lead to proposals for follow on CatAb engineering and AD mouse model studies performed in collaboration with the Sun Health Research Institute Neuroinflammation Laboratory (Sun City, AZ). We are excited about the potential impact of these first-ever "catalytically advantaged" AD therapeutics and are eager to initiate this research. PUBLIC HEALTH RELEVANCE: No satisfactorily effective treatment for Alzheimer's Disease (AD), a malady that afflicts more than 4.5 million Americans and has an economic impact exceeding $100 billion/yr, currently exists. Although the Receptor for Advanced Glycation End Products (RAGE) is known to play roles in multiple aspects of AD onset and progression, challenges in targeting therapies to this undesirable protein have led to only a single RAGE-targeted therapeutic being evaluated in clinical trials. We will develop a new class of RAGE-targeted therapeutics that are capable of destroying thousands of copies of the RAGE protein per single therapeutic molecule and hold the exciting potential to be the first truly efficacious AD therapeutics.