Bacterial chitinases as new virulence factors

细菌几丁质酶作为新的毒力因子

• 批准号: 7754036
• 负责人: NICHOLAS P CIANCIOTTO
• 金额: $ 18.98万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7754036
• 关键词: Address; Applications Grants; Area; Bacteria; Cells; Characteristics; Chitin; Chitinase; Data; Development; Disease; Enzymes; Epithelial Cells; Event; Family; Growth; Human; In Vitro; Infection; Inflammation; Inflammatory Response; Intestines; Laboratories; Lead; Legionella pneumophila; Legionnaires' Disease; Listeria; Listeria monocytogenes; Listeriosis; Location; Lung; Lung Inflammation; Microscopic; Modeling; Mus; Organism; Outcome; Pathogenesis; Pattern; Prevention; Protein Secretion; Proteins; Public Health; Research Personnel; Research Project Grants; Risk; Role; Septicemia; Staging; Techniques; Testing; Time; Tissues; United States National Institutes of Health; Virulence; Virulence Factors; Work; antimicrobial; disease diagnosis; macrophage; microbial; mutant; novel; pathogen; programs; public health relevance; research study; trafficking

DESCRIPTION (provided by applicant): Recently, we discovered that a secreted chitinase of Legionella pneumophila, the agent of Legionnaires' disease, promotes the persistence of the bacterium in the lungs of experimentally infected mice. In vitro experiments then documented that the L. pneumophila chitinase (ChiA) promotes growth in lung epithelial cells but not in macrophages. Taken together, these data are the first demonstration of a chitinase, a type of enzyme that is traditionally viewed as only being relevant in chitin-containing environmental niches, acting like a virulence factor. Thus, we hypothesize that bacterial chitinases represent a new class of virulence factor. To explore this hypothesis, we will further investigate the role of chitinase in L. pneumophila intracellular infection of lung cells as well as test for the first time the importance of a chitinase in the virulence of a second intracellular pathogen, Listeria monocytogenes. More specifically, we will determine the intracellular location of and trafficking patterns influenced by ChiA and begin to ascertain the effects of ChiA on the lung inflammatory response. For the Listeria experiments, new chitinase mutants will be constructed and then, after confirmation of their loss of chitinase activity and their in vitro growth characteristics, tested in murine models of listeriosis. The proposed studies will i) increase our understanding of the pathogenesis of Lp, which is an important public health concern within the US and throughout the world, ii) examine for the first time the role of chitinase in the pathogenesis of L. monocytogenes, an organism that is also an important public health concern, iii) expand our appreciation of bacterial intracellular infection and the novel role that a chitinase can have in it, iv) have implications for numerous other environmental pathogens that also express chitinases, and iv) offer potential new targets for disease diagnosis, treatment, or prevention. PUBLIC HEALTH RELEVANCE: We recently discovered that the secreted chitinase of Legionella pneumophila promotes bacterial persistence in the lungs of experimentally infected mice. From this novel finding, we hypothesize that microbial chitinases, which have traditionally been viewed as being relevant only in environmental niches, actually represent a new class of virulence factor and therefore are potential new targets for antimicrobial therapy. To explore this hypothesis, we will further investigate the role of chitinase in L. pneumophila intracellular infection of lung cells as well as test for the first time the importance of chitinases in the virulence of a second intracellular pathogen, Listeria monocytogenes.

描述（由申请人提供）：最近，我们发现嗜肺军团菌分泌的几丁质酶（军团病的病原体）促进细菌在实验感染小鼠的肺中的持久存在。体外实验证明L。嗜肺菌几丁质酶（ChiA）促进肺上皮细胞的生长，但不促进巨噬细胞的生长。总之，这些数据是第一次证明几丁质酶，一种酶，传统上被视为只在含几丁质的环境生态位相关，像一个毒力因子。因此，我们假设细菌几丁质酶代表一类新的毒力因子。为了进一步证实这一假说，我们将进一步研究几丁质酶在L.本研究首次证实了嗜肺菌胞内感染肺细胞的重要性，并首次测试了几丁质酶在第二种胞内病原体单核细胞增生李斯特菌毒力中的重要性。更具体地说，我们将确定细胞内的位置和运输模式的影响，ChiA和开始，以确定影响ChiA对肺部炎症反应。对于李斯特菌实验，将构建新的几丁质酶突变体，然后在确认其几丁质酶活性丧失及其体外生长特征后，在鼠的大肠杆菌病模型中进行测试。拟开展的研究将i）增加我们对Lp发病机制的理解，这是美国和全世界重要的公共卫生问题，ii）首次研究几丁质酶在Lp发病机制中的作用。单核细胞增多症，一种也是重要的公共卫生问题的生物体，iii）扩大了我们对细菌细胞内感染和几丁质酶在其中可能具有的新作用的认识，iv）对也表达几丁质酶的许多其他环境病原体具有意义，以及iv）为疾病诊断、治疗或预防提供了潜在的新靶标。公共卫生相关性：我们最近发现，嗜肺军团菌分泌的几丁质酶促进实验感染小鼠肺部的细菌持久性。从这一新的发现，我们假设，微生物几丁质酶，传统上被认为是相关的，只有在环境中的小生境，实际上代表了一类新的毒力因子，因此是潜在的新目标，抗菌治疗。为了进一步证实这一假说，我们将进一步研究几丁质酶在L.本研究首次证实了嗜肺菌胞内感染肺细胞的重要性，并首次测试了几丁质酶在第二种胞内病原体单核细胞增生李斯特菌毒力中的重要性。