Molecular mechanisms and novel biological-based therapies for anthrax lethal toxin-induced mortality

炭疽致命毒素引起的死亡的分子机制和新型生物疗法

• 批准号: 10246693
• 负责人: Shihui Liu
• 金额: $ 51.75万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10246693
• 关键词: Acute; Affect; Alleles; Animals; Anthrax Attack; Anthrax disease; Antibiotics; Antibodies; Bacillus anthracis; Bacterial Infections; Bioenergetics; Biological; Biological Process; Bioterrorism; Cardiac Myocytes; Caring; Cell Proliferation; Cell Survival; Cells; Cessation of life; Clinical; Clinical Management; Communicable Diseases; Complement; Data; Defense Mechanisms; Disease; Epidermal Growth Factor; Goals; Human; Impairment; Infection; Inhalation; MAP Kinase Gene; MAP2K1 gene; MAPK8 gene; MEKs; Medical; Medical Assistance; Metabolism; Metalloproteases; Mitogens; Molecular; Molecular Target; Organ; Pathogenesis; Pathway interactions; Patients; Play; Public Health; Research; Resistance; Role; Septic Toxemia; Stress; Symptoms; Testing; Therapeutic; Time; Tissues; Toxic effect; Toxin; Virulence Factors; anthrax lethal factor; antitoxin; base; c-myc Genes; cardiovascular collapse; evidence base; expectation; flu; in vivo; mortality; mouse model; novel; p38 Mitogen Activated Protein Kinase; pathogen; prevent; repaired; targeted treatment

Abstract Bacillus anthracis, the causative agent of anthrax disease, has remained as a top bioterrorism concern since the 2001 anthrax attack. B. anthracis causes anthrax through a combination of bacterial infection and toxemia. As a major virulence factor, the anthrax lethal toxin (LT) plays an essential role during multiple steps of the disease. Due to the rapid course of anthrax disease, in particular, the non-specific, flu-like symptoms of inhalational anthrax, patients usually seek medical assistance when the disease is already in the middle/late stages, making the clinical management of anthrax patients an extremely challenging task. Current treatments include antibiotics and anti-toxin antibodies that respectively eliminate the pathogen and neutralize the toxin. However, there is no therapy available to deal with the cellular/tissue damage caused by LT already having reached its molecular targets inside cells. Mortality usually follows when the host fails to repair this damage, the so called “point-of-no- return” for current therapy. Thus, even with intensive medical care, the mortality rate of systemic anthrax is high, reaching > 50%. Therefore, there is an urgent unmet clinical need to develop better targeted therapies to avert anthrax -induced mortality. Our goal in this application is to discover the molecular mechanisms underlying LT- induced lethality and to develop potential targeted therapeutics to treat patients beyond the “point-of-no-return”. Here, we set out to determine the specific roles of disrupting each of the ERK, p38, and JNK pathways in anthrax- induced lethality, discover the underlying molecular mechanisms, and develop the concept of reactivation /mobilization of these pathways as a targeted therapy for anthrax-induced mortality. In Aim 1, we will determine the role of specifically disrupting the ERK pathway in anthrax-induced lethality and explore ERK pathway reactivation as a targeted therapy. Among the three core MAPK pathways targeted by LT, the ERK pathway is fundamental to many biological processes, including cell proliferation and survival. Thus, we hypothesize that disrupting the ERK pathway is the major cause of anthrax-induced lethality. We will generate and use novel mouse models containing MEK1 and MEK2 alleles that are resistant to LT-cleavage to understand the precise role of ERK pathway inactivation in anthrax pathogenesis. We will further test this hypothesis and explore ERK pathway reactivation as a targeted therapy for anthrax-induced tissue damage. Importantly, our preliminary data demonstrate that the LT-disrupted ERK pathway can be reactivated by the addition of potent mitogens, such as epidermal growth factor. In Aim 2, we will further determine the roles of disrupting the p38 and JNK pathways in anthrax pathogenesis and explore the feasibility of mobilizing these pathways in anthrax-targeted therapy. Upon completion of these studies, it is our expectation that we will provide significant conceptual advances in our understanding of the underlying molecular mechanisms of anthrax LT and offer an evidence-based framework for developing anthrax-targeted therapies, which will complement the current therapies with antibiotics and anti-toxin antibodies, to prevent anthrax mortality, even at advanced stages of anthrax infection.

抽象的 自炭疽病爆发以来，炭疽杆菌一直是最令人担忧的生物恐怖主义问题。 2001年炭疽袭击。炭疽芽孢杆菌通过细菌感染和毒血症的结合引起炭疽。作为一个 作为主要毒力因子，炭疽致死毒素（LT）在疾病的多个阶段中发挥着重要作用。 由于炭疽病的病程迅速，特别是吸入性炭疽病的非特异性、类似流感的症状 炭疽病患者通常在疾病已处于中晚期时就医，这使得 炭疽患者的临床管理是一项极具挑战性的任务。目前的治疗方法包括抗生素 和抗毒素抗体，分别消除病原体和中和毒素。然而，没有 可用于处理已达到其分子水平的 LT 引起的细胞/组织损伤的疗法 细胞内的目标。当宿主无法修复这种损伤时，通常就会死亡，即所谓的“无法修复的点” 目前的治疗“回报”。因此，即使有重症监护，系统性炭疽的死亡率仍然很高， 达到>50%。因此，迫切需要开发更好的靶向治疗来避免 炭疽引起的死亡。我们在此应用中的目标是发现 LT- 的分子机制 诱导致死率并开发潜在的靶向治疗方法来治疗“不归路”的患者。 在这里，我们着手确定破坏炭疽病中 ERK、p38 和 JNK 通路的具体作用- 诱导致死，发现潜在的分子机制，并发展重新激活的概念 /动员这些途径作为炭疽引起的死亡率的靶向治疗。在目标 1 中，我们将确定 特异性破坏 ERK 通路在炭疽致死中的作用并探索 ERK 通路 重新激活作为靶向治疗。 LT 靶向的三个核心 MAPK 通路中，ERK 通路是 对许多生物过程至关重要，包括细胞增殖和生存。因此，我们假设 破坏 ERK 通路是炭疽致死的主要原因。我们将生成并使用小说 含有可抵抗 LT 裂解的 MEK1 和 MEK2 等位基因的小鼠模型，以了解精确的 ERK 通路失活在炭疽发病机制中的作用。我们将进一步检验这个假设并探索 ERK 通路再激活作为炭疽引起的组织损伤的靶向治疗。重要的是，我们的初步数据 证明 LT 破坏的 ERK 通路可以通过添加有效的有丝分裂原重新激活，例如 表皮生长因子。在目标 2 中，我们将进一步确定破坏 p38 和 JNK 通路在 炭疽发病机制并探索在炭疽靶向治疗中调动这些途径的可行性。 完成这些研究后，我们期望我们将在以下方面提供重大的概念进展： 我们对炭疽 LT 的潜在分子机制的理解并提供了基于证据的 开发炭疽靶向疗法的框架，这将补充当前的疗法 抗生素和抗毒素抗体，以预防炭疽死亡，即使是在炭疽感染的晚期。