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，我们发现军团疾病的肺炎军团菌的分泌几丁质酶促进了细菌在实验感染小鼠的肺中的持久性。然后，体外实验证明了肺炎乳杆菌（CHIA）促进肺上皮细胞的生长，但不能促进巨噬细胞的生长。综上所述，这些数据是几丁质酶的第一个证明，这种酶是一种传统上仅与含丁丁蛋白的环境壁ni相关的酶，其作用像是一种毒力因子。因此，我们假设细菌几丁质酶代表了一种新的毒力因子。为了探讨这一假设，我们将进一步研究几丁质酶在肺细胞内感染肺细胞内感染中的作用，并首次检验几丁质酶在第二种细胞内病原体李斯特菌单核细胞增生中的毒力中的重要性。更具体地说，我们将确定受CHIA影响的细胞内位置和运输模式的细胞内位置，并开始确定CHIA对肺部炎症反应的影响。对于李斯特菌实验，将构建新的几丁质酶突变体，然后在确认了几丁质酶活性损失及其体外生长特征后，在李斯特氏菌病模型中进行了测试。拟议的研究将i）提高我们对LP发病机理的理解，这是美国内部和世界范围内的重要公共卫生问题，ii）首次研究几核细胞增生李斯特氏菌的作用，这是一种有机体的作用，这是一种有机体，这是一种重要的公共卫生，这是一个重要的公共卫生，iii涉及我们对细菌内造成的互联症的意识，可以扩大奇特的依据。也表达几丁质酶的病原体，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，肺炎军团菌的分泌几丁质酶促进了实验感染小鼠的肺中的细菌持久性。从这个新颖的发现中，我们假设微生物几丁质酶通常被视为仅在环境壁ches中相关，实际上是一种新的毒力因子，因此是抗菌治疗的潜在新靶标。为了探讨这一假设，我们将进一步研究几丁质酶在肺细胞内感染肺细胞内感染中的作用，并首次检验几丁质酶在第二种细胞内病原体单细胞增生单细胞增生中的毒力中的重要性。