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晚期糖基化终产物受体（flRAGE）全长膜结合异构体，通过增加脑组织中β -淀粉样蛋白(2)的积累、增加炎症和升高氧化应激，促进阿尔茨海默病（AD）的发生和进展。尽管通过拮抗flRAGE与许多配体的结合来阻止其活化是一种很有吸引力的AD治疗策略，但毒性、低疗效和血脑屏障穿透性差限制了rage靶向治疗试验对一个小分子的应用，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抗体（CatAbs），每个CatAb能够使数千个flRAGE分子失活，作为一类新的“催化优势”治疗药物，有可能成为AD的第一个有效的疾病改善治疗方法。之前用于开发抗原结合抗体（BindAbs）以治疗一系列疾病的酵母表面展示平台将用于创建催化flRAGE特异性水解的人CatAbs。与其他flRAGE结合药物相比，catab能够催化数千个周期的短寿命flRAGE结合、flRAGE水解、产物释放和与另一种flRAGE分子的相互作用，这使得catab具有许多“催化优势”。如上述flRAGE拮抗剂试验所示，CatAbs的特异性和高剂量有效性降低了副作用的可能性。此外，CatAbs与BindAbs的特异性相匹配，每个Ab的失活靶标数量要高得多，这是考虑到血脑屏障对蛋白质药物的低渗透性的一个关键优势。此外，CatAbs的快速水解和释放flRAGE分子将允许在给药后表达的flRAGE靶点失活，这使CatAbs具有独特的能力来解释flRAGE的周转。最后，与flage拮抗剂不同，CatAbs不会与flage的循环异构体sRAGE进行长期结合，因此不太可能阻碍sRAGE促进的血浆中Ab的清除。我们将使用一种新颖的库设计方法来构建一个酵母显示的CatAb库，该库将作为多个flRAGE CatAb的来源。荧光活化细胞分选（FACS）将使先导flRAGE CatAb的分离和后续CatAb工程增强催化性能成为可能。CatAb水解小鼠细胞膜上表达的flRAGE将在体外验证。这项工作将导致与太阳健康研究所神经炎症实验室（太阳城，AZ）合作进行的CatAb工程和AD小鼠模型研究的后续建议。我们对这些首次“催化优势”的阿尔茨海默病治疗方法的潜在影响感到兴奋，并渴望启动这项研究。

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.