Inhibition of Anthrax Lethal Factor by alpha-defensins

α-防御素对炭疽致死因子的抑制

• 批准号: 8134677
• 负责人: WUYUAN LU
• 金额: $ 16.01万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-07 至 2011-09-06
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8134677
• 关键词: Affinity Labels; Alanine; Algorithms; Amino Acids; Animals; Anthrax antitoxin; Anthrax disease; Antigens; Antimicrobial Cationic Peptides; Antitoxins; Bacillus anthracis; Bacillus anthracis spore; Bacteria; Binding; Cell Culture Techniques; Cell membrane; Cessation of life; Cleaved cell; Complex; Cytolysis; Cytosol; Defensins; Dissociation; Doctor of Philosophy; Enzyme Kinetics; Enzymes; Epitopes; Equilibrium; Family; Generations; Human; Immune; Inbred BALB C Mice; Infection; MAP Kinase Gene; MAPK Signaling Pathway Pathway; Maps; Mass Spectrum Analysis; Metalloproteases; Microbe; Mitogen-Activated Protein Kinase Kinases; Molecular; Mus; Mutagenesis; Mutation; Pathogenesis; Phagocytes; Play; Positioning Attribute; Proteins; Reporting; Research Personnel; Role; Scanning; Signal Pathway; Signal Transduction; Spectrum Analysis; Surface Plasmon Resonance; Symptoms; Techniques; Testing; Therapeutic; Thermodynamics; Virulence Factors; Virus; affinity labeling; alpha-Defensins; analog; anthrax lethal factor; anthrax protective factor; anthrax toxin; base; cell killing; combat; cytotoxicity; design; drug development; edema factor; fungus; improved; in vivo; inhibitor/antagonist; killings; macrophage; member; neutrophil; novel; pathogen; prevent; programs; small molecule; therapeutic target; uptake

Anthrax toxin consists of three proteins secreted by Bacillus anthracis - protective antigen (PA), edema factor (EF) and lethal factor (LF). LF is a Zn2+-dependent metalloprotease that cleaves members of the mitogen-activated protein kinase kinase (MAPKK) family, blocking the MARK signaling pathway in professional phagocytes. The binary complex of PA and LF alone, termed lethal toxin or LeTx, is sufficient to nduce death of target cells and kill experimental animals, manifesting the symptoms associated with anthrax. As one of the primary virulence factors in the pathogenesis of anthrax, LF has become an important therapeutic target for drug development. A number of small-molecule-based inhibitors of LF have been shown to be able to neutralize cytotoxicityof LeTx in cell cultures and lethality of LeTx in animal trials, promising potential therapeutic value in the treatment of anthrax infection. Human neutrophil a-defensins (HNPs) are members of a growing family of small cationic antimicrobial peptides that kill a broad range of microbes such as bacteria, fungi and viruses, playing an important role in the innate immune defense against infectious pathogens. Kaufmann and colleagues recently discovered that HNP1 non-competitively inhibits LF, preventing cleavage of a MAPKK and restoring impaired MAPK signaling in LeTx-treated macrophages (Kim et al., 2005). Further, HNP1 rescued murine macrophages from B. a/tfftrac/s-induced cytotoxicity, and in wVo treatment with HNP1-3 protected mice against the fatal consequences of LeTx (Kim et al 2005). In a subsequent report, Mayer-Scholl et al. (2005) demonstrated that B. anthracis spores engulfed by human neutrophils and germinated intracellularly can be effectively killed by HNPs. These findings raise the possibility that a-defensins may be developed as a novel class of antitoxins to combat anthrax infection. Despite the therapeutic potential of a-defensin-based antitoxins for anthrax treatment, the molecular basis for the inhibition of LF by a-defensins remains poorly understood. In this proposal, we seek to decipher the sequence rules and structural determinants that dictate the inhibition of LF by a-defensins, and to design second-generation defensin molecules with significantly improved inhibitory activity.

炭疽毒素由三种由炭疽芽孢杆菌分泌的三种蛋白质 - 保护性抗原（PA），水肿 因子（EF）和致死因子（LF）。 LF是Zn2+依赖性的金属蛋白酶，裂解 有丝分裂原活化的蛋白激酶激酶（MAPKK）家族，阻止了标记信号通路 专业的吞噬细胞。单独使用PA和LF的二进制复合物称为致命的毒素或Letx，足以足以 靶细胞死亡并杀死实验动物，表现出与 炭疽病。作为炭疽病发病机理中的主要毒力因素之一，LF已成为重要 药物开发的治疗靶标。 LF的许多基于小分子的抑制剂已经 证明能够在细胞培养物中中和letx的细胞毒性和在动物试验中的杀伤力， 有望在治疗炭疽感染的治疗中潜在的治疗价值。 人类嗜中性粒细胞A-防御素（HNP）是不断增长的小阳离子抗菌家族的成员 杀死细菌，真菌和病毒等广泛微生物的肽，在 对感染性病原体的先天免疫防御。 Kaufmann及其同事最近发现 HNP1非竞争性抑制LF，防止MAPKK的裂解并恢复MAPK受损 LETX处理的​​巨噬细胞中的信号传导（Kim等，2005）。此外，HNP1从 B. A/TFFTRAC/S诱导的细胞毒性，在用HNP1-3保护的小鼠治疗中，针对致命的小鼠 LETX的后果（Kim等，2005）。在随后的报告中，Mayer-Scholl等人。 （2005）证明了 可以有效地有效地，可以有效地 被HNP杀死。这些发现提出了可以发展为新颖类的A-defensin的可能性 抗毒素以对抗炭疽感染。 尽管基于a-二弱的抗毒素用于炭疽治疗的治疗潜力，但分子的基础 为了抑制A-防御素的LF，对LF的理解仍然很少。在此提案中，我们试图破译 序列规则和结构决定因素决定了A-防御素对LF的抑制，并设计 第二代防御素分子具有显着改善的抑制活性。