DEVELOPMENT OF MULTIVALENT ANTHRAX TOXIN INHIBITORS

描述（由申请人提供）：最近发生的事件可怕地证明，炭疽作为恐怖主义和战争的生物武器，构成了致命的威胁。炭疽毒素的全身性中毒几乎总是致命的，但没有有效的治疗方法。这一应用的目标是开发有效的抑制剂，以防止炭疽毒素复合物的组装。炭疽毒素是造成这种疾病主要症状的原因。毒素包括一种宿主受体结合蛋白，称为保护性抗原（PA）和两种酶，称为致死因子（LF）和水肿因子（EF）。这些蛋白质作为无毒单体从炭疽芽孢杆菌中释放出来。它们扩散到宿主细胞表面并聚集成两种毒性蛋白复合物：致死毒素（LF+PA）和水肿毒素（EF+PA）。PA是将LF和EF从细胞表面转运到胞浆的必要载体，在胞浆中LF和EF发挥其细胞毒性作用。因此，阻止LF或EF与PA结合的抑制剂应该是一种有效的抗炭疽治疗方法。

DESCRIPTION (provided by applicant): As demonstrated so terribly by recent events, anthrax poses a deadly threat as a biological weapon of terrorism and warfare. Systemic intoxication by anthrax toxins is virtually always fatal but effective treatment is not available. The goal of this application is the development of potent inhibitors that prevent the assembly of anthrax toxin complexes. Anthrax toxins are responsible for the major symptoms of the disease. The toxins consist of a host receptor-binding protein termed protective antigen (PA) and two enzymes termed lethal factor (LF) and edema factor (EF). These proteins are released from Bacillus anthracis as nontoxic monomers. They diffuse to the surface of host cells and assemble into two types of toxic protein complexes, lethal toxin (LF+PA) and edema toxin (EF+PA). PA is the necessary vehicle that transports LF and EF from the cell surface to the cytosol where LF and EF exert their cytotoxic effects. Hence, inhibitors that prevent the binding of LF or EF to PA should provide an effective antitoxic therapy against anthrax. Previously, we have identified several peptides that bind PA weakly and inhibit the interactions of LF or EF with PA. We hypothesize that, through cooperative interactions, multivalent inhibitors (MVIs), in which multiple copies of a peptide are coupled to a carrier molecule, will display significantly enhanced inhibitory effects. In our preliminary study, we have synthesized several dextran-based MVIs that show higher inhibitory activities than peptides alone. We propose to develop optimized MVIs based on biocompatible, nontoxic, linear polymers and cyclic oligomers as carriers. Aim 1. To optimize MVIs based on dextran and pectin carriers. Aim 2. To explore MVIs based on polyglutamate backbones. Aim 3. To design and develop heptavalent "crown" MVIs based on (-cyclodextrin cores. In Aims 1 and 2, we plan to synthesize a series of peptide-polymer conjugates in which the peptide-to-backbone ratio and the molecular size of the backbone are systematically varied. In Aim 3, we will assist the design of crown inhibitors by computational modeling. We will test all MVIs in our established inhibition assays and the most active MVIs in two rat intoxication models. Potent inhibitors developed in this study can help to protect us from deadly anthrax disease and fight the threat of anthrax bioterrorism.