Highly specific anti-toxin therapies for severe bacterial gut infections

针对严重细菌性肠道感染的高度特异性抗毒素疗法

• 批准号: 9055644
• 负责人: Brett D Welch
• 金额: $ 29.74万
• 依托单位: NAVIGEN, INC.
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2017-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9055644
• 关键词: Acute; Affinity; Amino Acids; Antibiotics; Antibodies; Applications Grants; Avidity; Bacteriophages; Binding; Biochemical; Bioinformatics; Biological Assay; Blood Circulation; Categories; Cell Surface Proteins; Cells; Centers for Disease Control and Prevention (U.S.); Child; Childhood; Circular Dichroism; Clinic; Communicable Diseases; Complication; Consensus; Consensus Sequence; Coupled; Developing Countries; Disease Outbreaks; Diversity Library; Drug Design; Ebola virus; Endocytosis; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli EHEC; Escherichia coli Infections; Escherichia coli O157:H7; Escherichia coli Vaccines; Face; Food; Food Contamination; Food Poisoning; Fruit or Vegetable; Grant; HIV; Health; Hemolytic-Uremic Syndrome; Hemorrhagic colitis; Image; In Vitro; Individual; Infection; Kidney Failure; L Forms; Lead; Libraries; Life; Measures; Membrane Glycoproteins; Molecular Conformation; Pain; Peptide Hydrolases; Peptides; Phage Display; Phase; Positioning Attribute; Preclinical Drug Evaluation; Production; Protein Engineering; Proteins; Random Peptide Libraries; Resolution; Risk; Route; Sampling; Severities; Shiga Toxin; Shiga-Like Toxin I; Shigella dysenteriae; Source; Specificity; Structure; Supportive care; Surface Plasmon Resonance; Technology; Therapeutic Uses; Toxicology; Toxin; Viral; Virulence Factors; Virulent; Water; X-Ray Crystallography; animal efficacy; base; combat; contaminated water; cross reactivity; deep sequencing; design; drug discovery; effective therapy; env Gene Products; foodborne; global health; immunogenicity; in vitro activity; in vivo; inhibitor/antagonist; innovation; mutant; novel; pathogen; pathogenic bacteria; peptide L; peptide drug; preclinical trial; prevent; public health priorities; receptor binding; screening; small molecule; success; waterborne

 DESCRIPTION (provided by applicant): Shiga toxins 1 and 2 (Stx1/2) are the primary virulence factors of Shiga toxin-producing E. coli (STEC), which are major food-, and waterborne pathogens afflicting both developed and developing countries. An estimated 265,000 STEC infections occur annually in the US. In addition to severe and often bloody diarrhea, the life-threatening complication hemolytic uremic syndrome (HUS) occurs in 2-7% of victims (primarily children). No STEC vaccines or therapies beyond supportive care are available. Antibiotics are not used since they can increase toxin production and risk of HUS. The severity of STEC infection, propensity for outbreaks, and lack of effective treatments make STEC concerning potential bioterror agents and a public health priority. Here, we describe an innovative strategy to discover D-peptide inhibitors of Stx1/2 to combat STEC infection. D-peptides, the mirror images of natural L-peptides, cannot be digested by proteases and, therefore, have the potential for long in vivo half-lives and low immunogenicity. They can readily disrupt protein interfaces with high potency and specificity compared to small molecules and are much less expensive to produce than antibodies. D-peptides are ideal candidates for Stx1/2 neutralization in the gut and/or systemic circulation. Navigen's drug discovery platform employs an enantiomeric screening technology (mirror-image phage display) coupled with protein design. We have successfully validated this platform technology by identifying D- peptide inhibitors of HIV, RSV, and Ebola. Our anti-HIV D-peptide was the first potent and specific D-peptide inhibitor to be discovered and is in advanced preclinical trials. It binds a functionally critical and conserved hydrophobic "pocket" on HIV's trimeric surface glycoprotein, gp41. A trimeric version of this D-peptide binds to all three gp41 pockets, providing a strong avidity boost. Stx1/2 is each composed of a single enzymatically active A subunit and five receptor-binding B subunits that form a pentameric ring. Each of the B pentamer subunits contains a vulnerable pocket analogous to those of our viral targets. The Stx1/2 B subunit pockets are excellent targets for us to next apply our expertise in D- peptide drug design given 1) our success in targeting analogous pockets at functionally critical interfaces, 2) the pentameric Stx1/2 target, which inspires design of pentameric D-peptides with strong avidity, and 3) the likelihood of D-peptide stability and activity in the gut without disturbing native flora. Furthermore, the B subunits of Stx1 and Stx from Shigella dysenteriae are identical, enabling dual therapeutic use for an anti- Stx1B D-peptide. These benefits have generated strong enthusiasm for this project from GI infectious disease clinicians, who understand the dramatic potential impact an anti-Stx1/2 D-peptide would have in the clinic. In this two-year grant, we propose to discover, structurally characterize, and optimize pentameric D-peptide inhibitors that will neutralize Stx1/2 with high potency. Success in this project will launch a new class of inhibitors against pathogenic bacteria important to global health.

 描述（由申请人提供）：志贺毒素 1 和 2 (Stx1/2) 是产生志贺毒素的大肠杆菌 (STEC) 的主要毒力因子，它们是困扰发达国家和发展中国家的主要食品和水传播病原体。据估计，美国每年发生 265,000 例 STEC 感染，除了严重的血性腹泻外，还有危及生命的并发症溶血性尿毒症综合征。 (HUS) 发生于 2-7% 的受害者（主要是儿童）。除了支持性治疗外，没有可用的抗生素，因为它们会增加毒素的产生和 HUS 的风险。爆发和缺乏有效的治疗方法使 STEC 成为潜在的生物恐怖剂和公共卫生优先事项，在此，我们描述了一种发现 Stx1/2 的 D 肽抑制剂来对抗 STEC 感染的创新策略。天然L-肽不能被蛋白酶消化，因此具有长体内半衰期和低免疫原性的潜力，与小分子相比，它们可以以高效和特异性轻松破坏蛋白质界面，并且成本低得多。 D-肽是肠道和/或全身循环中 Stx1/2 中和的理想候选者，Navigen 的药物发现平台采用对映体筛选技术（镜像噬菌体展示）。我们通过识别 HIV、RSV 和埃博拉病毒的 D-肽抑制剂，成功验证了该平台技术。我们的抗 HIV D-肽是第一个被发现的有效且特异性的 D-肽抑制剂，并且处于高级临床前阶段。它与 HIV 三聚体表面糖蛋白 gp41 上的功能关键且保守的疏水“口袋”结合，该 D 肽的三聚体版本与所有三个 gp41 口袋结合，提供了强大的功能。 Stx1/2 均由一个酶活性 A 亚基和五个受体结合 B 亚基组成，形成五聚体环。每个 B 五聚体亚基都包含一个与我们的病毒靶点类似的脆弱口袋。 2 B 亚基口袋是我们接下来应用我们在 D-肽药物设计方面的专业知识的绝佳目标，因为 1) 我们成功地在功能关键的界面上靶向类似的口袋，2) 五聚体Stx1/2 靶点，激发了具有强亲合力的五聚体 D 肽的设计，3) D 肽在肠道中稳定性和活性而不干扰天然菌群的可能性此外，来自志贺氏菌的 Stx1 和 Stx 的 B 亚基是这些优点引起了胃肠道传染病爱好者对这个项目的强烈热情，他们了解抗 Stx1/2 的巨大潜在影响。 D-肽将进入临床。在这项为期两年的资助中，我们建议发现、结构表征和优化五聚体 D-肽抑制剂，该抑制剂将高效中和 Stx1/2。该项目的成功将推出一个新的类别。对全球健康重要的病原菌抑制剂。