Ampetoids as Biostable Functional Mimics of Antimicrobial Peptides

描述(申请人提供)：我们建议创建和研究一种新的用于抗菌应用的仿生低聚物家族。特别是，我们的目标是创造生物稳定的、具有功能的天然抗菌肽(AMPs)的模拟物，AMP是从人类到细菌的无数生物宿主防御系统中不可或缺的有效组成部分。通过优先与细菌细胞膜结合、破坏或透过细菌细胞膜，这些表面活性多肽能够杀死广泛的微生物。许多药物也是有选择性的，不会对哺乳动物细胞造成伤害。这种杀死机制虽然不完全清楚，但已经足够普遍，以至于细菌在数百万年的时间里一直无法进化出对AMPS的抵抗力。因此，AMPs良好的功能模拟物有望成为一类新的抗生素化合物，这些化合物可以直接在溶液中作用，或者被绑在生物医学设备的表面上，以防止感染。我们建议创建非天然的AMP模拟物，因为多肽本身容易蛋白质分解，因此在体内降解太快，而且因为多肽在体内通常具有免疫原性。特别是，我们的新型模拟物将基于两亲性、序列特异性的寡聚-N-取代甘氨酸(“类肽”)。类肽在结构上与多肽非常相似，但对蛋白酶具有抵抗力。它们很容易通过高产率的固相协议合成，允许容易地加入仿生侧链。此外，类肽可以被设计成形成稳定的仿生螺旋，在水和生物膜环境中都保持其折叠结构，并且高度抵抗变性。在前期工作中，我们已经证明了某些模拟抗菌肽的两亲性序列模式和螺旋结构的类肽序列(9-17mer)是有效的和选择性的抗菌药物(对大肠杆菌的MIC~4M和对枯草杆菌的MIC~820 nm，对E.ColiMIC的溶血可以忽略不计)。我们建议进一步研究和开发这些化合物，方法是：(1)通过详细的生物物理研究，探索结构-功能关系和作用机制(S)，通过详细的生物物理研究具有不同效力/选择性轮廓的密切相关的肽类化合物；(2)创造模仿天然AMP的结构基序的新型肽类化合物，包括脂化、环化和缠结的肽类化合物；(3)测试它们对抗生素耐药细菌的抗生素活性以及对人类细胞的早期毒性研究。

DESCRIPTION (provided by applicant): We propose to create and study a new family of biomimetic oligomers for antibacterial applications. In particular, we aim to create biostable, functional mimics of natural antimicrobial peptides (AMPs), which are an integral and effective part of the host-defense systems of myriad organisms ranging from humans to bacteria. By preferentially binding to and disrupting or permeating bacterial cell membranes, these surface- active peptides are able to kill a broad spectrum of microorganisms. Many are also selective, causing no harm to mammalian cells. The killing mechanism, while imperfectly understood, is sufficiently general that bacteria have been unable to evolve resistance to AMPs over millions of years. Thus, good functional mimics of AMPs hold forth the promise of serving as a new class of antibiotic compounds, which could act in solution directly or be tethered to the surfaces of biomedical devices to stave off infection. We propose to create non-natural mimics of AMPs, since peptides themselves are vulnerable to proteolysis and hence degrade too rapidly in the body, and moreover because peptides are often immunogenic in vivo. In particular, our novel mimics will be based on amphipathic, sequence-specific oligo-N-substituted glycines ("peptoids"). Peptoids are quite similar in structure to peptides, yet are protease-resistant. They are easily synthesized by a high-yielding, solid-phase protocol that allows the easy incorporation of biomimetic side chains. Moreover, peptoids can be designed to form stable, biomimetic helices that keep their folded structure in both aqueous and biomembrane environments, and which are highly resistant to denaturation. In preliminary work, we have shown that certain peptoid sequences (9-17mers) designed to mimic the amphipathic sequence patterning and helical structure of antimicrobial peptides are potent and selective antibacterials (MIC ~ 4 ¿M against E. coli and 820 nM against B. subtilis, with negligible hemolysis at the E. coli MIC). We propose to further study and develop these compounds, by (1) exploring structure-function relationships and mechanism(s) of action through detailed biophysical studies of a "basis set" of closely related peptoids with differing potency/selectivity profiles, (2) creating novel peptoids that mimic structural motifs of natural AMPs, including peptoids that are lipidated, cyclized, and kinked; (3) testing their antibiotic activity against antibiotic-resistant bacteria as well as early-stage investigation of their toxicity to human cells.