Cytotoxic mechanisms of Aggregatibacter actinomycetemcomitans leukotoxin

放线菌白毒素聚集杆菌的细胞毒机制

• 批准号: 8787939
• 负责人: Angela C. Brown
• 金额: $ 24.67万
• 依托单位: LEHIGH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8787939
• 关键词: Actinobacillus actinomycetemcomitans; Affect; Area; Bacteria; Bacterial Proteins; Behavior; Binding; Biological; Cell membrane; Cells; Cercopithecidae; Child; Cholesterol; Clinical Data; Complex; Cosmetics; Cytosol; Defect; Deformity; Development; Devices; Disease; Disease Progression; Drug Delivery Systems; Elements; Engineering; Environment; Faculty; Family; Grant; Host Defense Mechanism; Human; Immune; Immune response; Infection; Infective endocarditis; Intervention; Lead; Leukocytes; Lipids; Literature; Membrane; Membrane Microdomains; Mentors; Pathogenesis; Peptides; Periodontal Diseases; Periodontal Ligament; Periodontitis; Pharmaceutical Preparations; Phase; Play; Pongidae; Positioning Attribute; Primates; Process; Proteins; Research; Research Personnel; Role; Structure; Systemic infection; Tail; Targeted Toxins; Techniques; Therapeutic; Therapeutic Agents; Tooth Loss; Tooth structure; Toxic effect; Toxin; Training; United States; Virulence Factors; Work; Writing; alveolar bone; base; career; cellular targeting; cytolethal distending toxin; cytotoxic; cytotoxicity; design; killings; leukotoxin; man; medically underserved; member; microbial; novel therapeutics; pathogen; phase change; porin; prevent; receptor; response; Actinobacillus actinomycetemcomitans; Affect; Area; Bacteria; Bacterial Proteins; Behavior; Binding; Biological; Cell membrane; Cells; Cercopithecidae; Child; Cholesterol; Clinical Data; Complex; Cosmetics; Cytosol; Defect; Deformity; Development; Devices; Disease; Disease Progression; Drug Delivery Systems; Elements; Engineering; Environment; Faculty; Family; Grant; Host Defense Mechanism; Human; Immune; Immune response; Infection; Infective endocarditis; Intervention; Lead; Leukocytes; Lipids; Literature; Membrane; Membrane Microdomains; Mentors; Pathogenesis; Peptides; Periodontal Diseases; Periodontal Ligament; Periodontitis; Pharmaceutical Preparations; Phase; Play; Pongidae; Positioning Attribute; Primates; Process; Proteins; Research; Research Personnel; Role; Structure; Systemic infection; Tail; Targeted Toxins; Techniques; Therapeutic; Therapeutic Agents; Tooth Loss; Tooth structure; Toxic effect; Toxin; Training; United States; Virulence Factors; Work; Writing; alveolar bone; base; career; cellular targeting; cytolethal distending toxin; cytotoxic; cytotoxicity; design; killings; leukotoxin; man; medically underserved; member; microbial; novel therapeutics; pathogen; phase change; porin; prevent; receptor; response

4.4.7 Project Summary Aggregatibacter actinomycetemcomitans is a Gram-negative pathogen that is the etiologic agent of localized aggressive periodontitis (LAP) and other systemic infections, including infective endocarditis. LAP, which affects medically-underserved children in both the United States and throughout the world, is characterized by a breakdown of the periodontal ligament and alveolar bone structure that holds the teeth in place. Without intervention, loss of teeth occurs, causing both a cosmetic deformity and a functional defect. The manner in which A. actinomycetemcomitans causes LAP is not known; however, it is known that it produces several putative virulence factors, including a leukotoxin (LtxA), a member of the repeats-in-toxin (RTX) family. Based on experimental and clinical data, LtxA is believed to be a primary virulence factor for the bacterium. Thus, preventing or interfering with LtxA activity may be one option for treatment of disease. The toxin kills human and primate white blood cells and likely plays a role in A. actinomycetemcomitans evasion of the immune response during infection. It has been demonstrated that in its initial response with the host cell membrane, LtxA does not form a pore, but rather destabilizes the membrane. Additionally, LtxA is internalized within the cell, where it binds to the intracellular region of its receptor. In the mentored phase of this study, we will investigate the mechanisms of these two findings. In our first aim, we will identify the structural domains of LtxA that are responsible for membrane destabilization. The second aim will allow us to define the mechanism of internalization and determine the structural domains of LtxA that are responsible for internalization. In the independent phase of the study, these mechanisms and structural domains will be exploited in the design of therapeutic devices. In the third aim, a device to block LtxA activity by interfering with the cellular targets of the toxin will be developed. In the fourth aim, the internalization mechanism of LtxA will be utilized in the design of a drug-delivery device to carry a drug directly to the cytosol of a cell. The research will answer vital questions about the mechanisms by which LtxA kills host cells. In addition, the work will lead to the development of therapeutic agents, one with specific activity against LtxA and RTX toxicity and another with more general applications. During this work, the PI will be trained in the necessary biological techniques during the mentored phase of the research that will be vital to her planned career as an independent investigator in microbial pathogenesis. Other elements of the proposed training plan, such as coursework, grant-writing, and a mentored faculty position search, will allow the PI to transition to an independent career in which she applies her engineering background to the study of microbial pathogenesis.

4.4.7项目摘要 聚集放线菌的聚集术是一种革兰氏阴性病原体，是局部化的病因学药 侵略性牙周炎（LAP）和其他全身感染，包括感染性心内膜炎。圈，哪个 在美国和世界各地影响医学表现的儿童的特点是 将牙齿固定在适当的牙周韧带和肺泡骨结构的分解。没有 干预，牙齿丧失发生，既导致美容畸形又导致功能缺陷。方式 A.放线菌的症状导致膝盖尚不清楚；但是，众所周知，它产生了几个 推定的毒力因子，包括白细胞毒素（LTXA），是重复毒素（RTX）家族的成员。基于 在实验和临床数据上，LTXA被认为是细菌的主要毒力因子。因此， 预防或干扰LTXA活性可能是治疗疾病的一种选择。毒素杀死人 和灵长类动物白细胞，并可能在A.放线菌逃避免疫的曲霉中发挥作用 感染期间的反应。 已经证明，在其对宿主细胞膜的初始响应中，LTXA不会形成孔， 而是使膜不稳定。另外，LTXA在细胞内被内化，在该单元中结合到 其受体的细胞内区域。 在这项研究的指导阶段，我们将研究这两个发现的机制。在我们的第一个目标中 我们将确定负责膜不稳定的LTXA的结构域。第二个 目的将使我们能够定义内在化的机制，并确定LTXA的结构域 负责内在化。在研究的独立阶段，这些机制和结构 在治疗设备的设计中将利用域。在第三个目标中，一种阻止LTXA活动的设备 通过干扰毒素的细胞靶标。在第四个目标中，内在化 LTXA的机制将用于设计药物送达装置的设计，直接将药物携带到细胞质上 细胞。 该研究将回答有关LTXA杀死宿主细胞的机制的重要问题。另外， 工作将导致治疗剂的发展，一种具有针对LTXA和RTX毒性的特定活性 另一个具有更通用的应用程序。 在这项工作中，PI将在指导阶段进行必要的生物技术培训 对于她作为微生物发病机理独立研究者计划的职业至关重要的研究。 拟议的培训计划的其他要素，例如课程，赠款写作和指导的教师 位置搜索，将允许PI过渡到她应用工程的独立职业 微生物发病机理研究的背景。