Screening of Combinatorial Libraries for Complement C5 Inhibitors

描述(申请人提供)：补体是存在于血液中的一种免疫效应系统，其功能是保护身体免受微生物的侵袭，但在调节失调的情况下，补体参与各种病理，包括老年性黄斑变性、多发性硬化症、格林-巴氏综合征、关节炎和溶血性贫血。然而，到目前为止，只有一种补体疗法Eculizumab，一种针对C5的单抗，已获得FDA批准用于治疗溶血性贫血。因此，迫切需要有效的治疗方法来驯服各种疾病中的异常补体炎症和膜溶解。鉴于补体介导的病理的多样性，治疗策略的武器库需要开发。目前正在开发的控制多余补体激活的分子靶点包括C3和C5，它们在途径中起关键作用。C5是我们特别感兴趣的，因为激活会导致炎症性多肽C5a和更大的片段C5b的释放，C5b启动膜攻击复合体的形成，从而破坏靶膜。此外，我们有研究C5的许多功能和结构方面的经验；因此，我们处于有利地位，专注于C5发现特定的抑制剂。为此，正在开发适合于筛选化学文库的分析方法，以便识别拮抗C5相互作用的探针。这包括三套测定C5相互作用的结合试验，即与C3b的可逆相互作用，与C6和C7的可逆相互作用，以及与C6的不可逆结合。这些检测方法适用于中等(目标1)和高通量筛选(目标2)。该计划是从Torrey Pines分子研究所(目标3)初步筛选组合肽文库。这些是该研究所开发的独特资源，由数百万个条目组成。如果筛选成功并产生特异的抑制性多肽，这将构成一个长期项目的第一步，该项目旨在发现能够在发生不受控制的补体激活的病理情况下进行治疗干预的新药物。

DESCRIPTION (provided by applicant): Complement is an immune effector system present in blood that functions to protect the body against microorganisms, but in situations of dysregulation, complement participates in a variety of pathologies inclusive of age-related macular degeneration, multiple sclerosis, Guillain-Barr syndrome, arthritis, and hemolytic anemias. However, to date only one complement therapeutic, Eculizumab, a mAb directed against C5, has attained FDA approval to treat hemolytic anemias. Accordingly, there is a pressing need for effective therapeutics that can tame aberrant complement inflammation and membranolysis in a variety of disorders. Given the diversity of complement mediated pathologies, an arsenal of therapeutic strategies requires development. Molecular targets to control unwanted complement activation currently under development include those to C3 and C5, which act pivotally in the pathways. C5 is of particular interest to us because activation results in the release of the inflammatory peptide C5a, and a larger fragment C5b that initiates the formation of the Membrane Attack Complex, which damages target membranes. Furthermore, we have experience investigating many functional and structural aspects of C5; therefore, we are well positioned to focus at C5 for discovery of specific inhibitors. For this purpose, assays are being developed that are suitable for screening chemical libraries in order to identify probes that antagonize C5 interactions. These include three sets of binding assays to measure C5 interactions, namely the reversible interaction with C3b, the reversible interaction with C6 and C7, and the irreversible binding to C6. These assays are suitable for medium (Aim 1) and high throughput screening (Aim 2). The plan is to screen initially combinatorial peptide libraries from the Torrey Pines Institute for Molecular Studies (Aim 3). These are a unique resource that were developed at this Institute, and are constituted by millions of entries. If the screening succeeds and yields inhibitory peptides that are specific, this would constitute the initial step of a long range project to discover new agents that can therapeutically intervene in pathological situations in which uncontrolled complement activation occurs.