Virulence Mechanisms of the Emerging Pathogen Stenotrophomonas maltophilia

新兴病原体嗜麦芽寡养单胞菌的毒力机制

• 批准号: 8867607
• 负责人: NICHOLAS P CIANCIOTTO
• 金额: $ 22.47万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-08 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8867607
• 关键词: A549; Actins; Address; Antibiotics; Area; Bacteremia; Bacteria; Blood Circulation; Cell Death; Cell Line; Cells; Cessation of life; Clinical; Data; Databases; Development; Disease; Disease model; Enzymes; Epithelial Cells; Experimental Designs; Eye; Foundations; Future; Genomics; Gram-Negative Bacteria; Grant; Human; Infection; Inflammation; Inflammatory Response; Lead; Lung; Mediating; Methods; Modeling; Molecular; Multi-Drug Resistance; Mus; Nature; Outcome; Pathogenesis; Peptide Hydrolases; Pneumonia; Prevention; Protein Export Pathway; Protein Secretion; Proteins; Publishing; Relative (related person); Research; Research Project Grants; Resistance; Respiratory System; Respiratory tract structure; Risk; Role; Sepsis; Serine Protease; Skin; Soft Tissue Infections; Staging; Stenotrophomonas maltophilia; System; Testing; Tissues; Toxin; United States National Institutes of Health; Urinary tract; Virulence; Virulence Factors; Work; base; disease diagnosis; disorder prevention; genome sequencing; in vivo; insight; multi-drug resistant pathogen; mutant; pathogen; programs; public health relevance

 DESCRIPTION (provided by applicant): Stenotrophomonas maltophilia (Sm) is an environmental, Gram-negative bacterium that has recently emerged as an important opportunistic and nosocomial pathogen, particularly of the respiratory tract and bloodstream. Infection with S. maltophilia is often very difficult to treat because of the resistance that S. maltophilia strains have toward multiple types of antibiotics. Despite the role of Sm in pneumonia, bloodstream infections, and various other diseases, including urinary tract, CNS, eye, skin, and soft tissue infections, the pathogenesis of Sm has been grossly understudied. With the aid of a small NIH R03 grant, we previously embarked upon research aimed at developing methods to study Sm. After having established a murine model for Sm pneumonia and developed means for mutagenizing the sequenced Sm strain K279a, we investigated the functioning of type II protein secretion (T2S) in Sm. Previous work from our lab and others had shown that T2S systems are major facilitators of virulence in various pathogens, including other agents of pneumonia and bloodstream infection. Proteins secreted via T2S typically include a wide variety of degradative and tissue- destructive enzymes. We documented that the Xps T2S system is functional in strain K279a, secreting at least seven protein species. Importantly, we determined that Xps mediates the export of two serine proteases (StmPr1 and StmPr2) that cause a human lung epithelial cell line (i.e., type I A549 cells) to undergo rounding, actin-rearrangement, detachment, and death. Thus, we hypothesize that Xps T2S and its substrates, including StmPr1 and StmPr2, are critical in the pathogenesis of S. maltophilia. Genomic data further indicate that Sm possesses a second T2S system (Gsp) as well as type IV (T4S) and type I (T1S) protein secretion systems. We hypothesize that proteins secreted by these other systems also represent virulence factors of Sm. To address these hypotheses, we propose to i) test the Xps mutant in two different murine models of disease, the published pneumonia model and a new bacteremia model (Aim 1), ii) test a stmPr1 stmPr2 mutant in the pneumonia and bacteremia models, and with confirmation of the importance of StmPr1 and/or StmPr2 begin to determine how the proteases mediate host cell death (Aim 2), and iii) test Gsp, T4S, and T1S mutants in the two disease models. From the results of this exploratory R21 grant, we will establish a working foundation for the nascent Sm pathogenesis field such that future efforts will be able to focus on characterizing the secretion system(s) and secreted proteins that are most important. In addition to providing much-needed insight into Sm pathogenesis, the data obtained have the potential to both uncover new types of virulence determinants and lead to new forms of disease diagnosis, treatment, or prevention. .

 描述（由适用提供）：促嗜性嗜性嗜性菌（SM）是一种环境，革兰氏阴性细菌，最近已成为一种重要的机会性和医疗性病原体，尤其是呼吸道和血液。由于麦芽链球菌菌株对多种类型的抗生素具有抗性，因此通常很难治疗麦芽葡萄球菌的感染。尽管SM在肺炎，血液感染和其他各种疾病中的作用，包括尿路，中枢神经系统，眼睛，皮肤和软组织感染，但SM的发病机理已被深知。借助小型NIH R03赠款，我们以前开始研究旨在开发研究SM的方法的研究。在建立了用于SM肺炎的鼠模型并开发了诱变的诱变方法K279a之后，我们研究了SM中II型蛋白质分泌（T2S）的功能。我们实验室和其他实验室的先前工作表明，T2S系统是各种病原体中病毒的主要促进因子，包括其他肺炎和血液感染的药物。通过T2S分泌的蛋白质通常包括多种降解和组织破坏性酶。我们记录了XPS T2S系统在K279a菌株中起作用，至少分泌七个蛋白质。重要的是，我们确定XPS介导了两种丝氨酸蛋白（STMPR1和STMPR2）的导出，这些丝氨酸蛋白（STMPR1和STMPR2）导致人类肺上皮细胞系（即I型A549型细胞）下线，肌动蛋白 - 重素，分离，脱离和死亡。这是我们假设XPS T2S及其底物（包括STMPR1和STMPR2）在麦芽链球菌的发病机理中至关重要。基因组数据进一步表明SM具有第二个T2S系统（GSP）以及IV型（T4S）和I型（T1S）蛋白质分泌系统。我们假设这些其他系统分泌的蛋白质也代表了SM的病毒因子。为了解决这些假设，我们建议i）在两个不同的鼠类疾病模型中测试XPS突变体，已发表的肺炎模型和一个新的细菌模型（AIM 1），ii）在肺炎和细菌中测试STMPR1 STMPR1 STMPR2突变体，并确认了STMPR1和STMPR 2的重要性，并确认了两种蛋白质的蛋白质。 iii）在两个疾病模型中测试GSP，T4S和T1S突变体。根据这项探索性R21赠款的结果，我们将为新生的SM发病机理建立一个工作基础，以便未来的努力将能够专注于表征最重要的分泌系统和分泌的蛋白质。除了提供对SM发病机理的急需的见解之外，获得的数据还具有发现新型病毒确定剂的潜力，并导致新形式的疾病诊断，治疗或预防。