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: 8475589
• 负责人: Angela C. Brown
• 金额: $ 7.76万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8475589
• 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; Principal Investigator; 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

DESCRIPTION (provided by applicant): Aggregatibacter ctinomycetemcomitans 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, on with specific activity against LtxA and RTX toxicity and another with more general applications. During this work, the principal investigator 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 principal investigator to transition to an independent career in which she applies her engineering background to the study of microbial pathogenesis.

描述（由申请人提供）：聚集的ctinomycetemcomitans是一种革兰氏阴性病原体，是局部侵袭性牙周炎（LAP）和其他全身感染（包括感染性心内膜炎）的病因。在美国和全世界都影响医学表现的儿童的膝盖的特征是牙周韧带和牙槽骨结构的分解。如果不干预，就会发生牙齿损失，从而导致美容畸形和功能缺陷。未所知的曲霉叶霉菌引起膝盖的方式；但是，众所周知，它产生了几种推定的毒力因子，包括白细胞毒素（LTXA），这是重复毒素（RTX）家族的成员。根据实验和临床数据，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。毒素杀死了人类和灵长类动物白细胞，并可能在感染过程中逃避放线菌对免疫反应的作用。已经证明，在其对宿主单元的初始响应中 膜，LTXA不会形成毛孔，而是破坏膜的稳定性。另外，LTXA在细胞中内部化，并在其受体的细胞内区域结合。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。第二个目标将使我们能够定义内在化的机制，并确定负责内在化的LTXA的结构域。在研究的独立阶段，这些机制和结构结构域将在治疗设备的设计中得到利用。在第三个目标中，通过干扰LTXA活动的设备 随着毒素的细胞靶标，将开发出来。在第四个目标中，LTXA的内部化机制将用于设计药物的设计直接携带药物 到细胞的细胞质。该研究将回答有关LTXA杀死宿主细胞的机制的重要问题。此外，这项工作将导致治疗剂的发展，具有针对LTXA和RTX毒性的特定活性，而另一种则具有更一般的应用。在这项工作中，首席研究人员将接受必要的生物学技术培训 在研究的指导阶段，这对于她作为微生物发病机理独立研究者的计划职业至关重要。拟议的培训计划的其他要素，例如课程，授予写作和指导的教师职位搜索，将使首席研究人员能够过渡到独立的职业，在该职业中，她将工程背景应用于微生物发病机理的研究。

项目成果

Association of Vibrio cholerae 569B outer membrane vesicles with host cells occurs in a GM1-independent manner.

• DOI: 10.1111/cmi.12828
• 发表时间: 2018-06
• 期刊: Cellular microbiology
• 影响因子: 3.4
• 作者: Rasti ES;Schappert ML;Brown AC
• 通讯作者: Brown AC

Receptor-Based Peptides for Inhibition of Leukotoxin Activity.

• DOI: 10.1021/acsinfecdis.7b00230
• 发表时间: 2018-07-13
• 期刊: ACS infectious diseases
• 影响因子: 5.3
• 作者: Krueger E;Hayes S;Chang EH;Yutuc S;Brown AC
• 通讯作者: Brown AC