Determinants of bacterial biofilm formation at the intestinal mucosal interface and their roles in pathogen exclusion

肠粘膜界面细菌生物膜形成的决定因素及其在病原体排除中的作用

• 批准号: 10598410
• 负责人: Josephine Ni
• 金额: $ 16.04万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10598410
• 关键词: Address; Anabolism; Animal Model; Bacteria; Bacterial Infections; Biologic Characteristic; Biological; Biological Assay; Biological Models; Body Weight decreased; Cell Adhesion; Characteristics; Chelating Agents; Chemicals; Citrobacter rodentium; Colitis; Colon; Colonic Diseases; Colorectal Cancer; Communities; Complement; Complex; Confocal Microscopy; Data; Dental caries; Dietary Iron; Disease; Engineered Gene; Engineering; Enterobactin; Environment; Escherichia coli; Exclusion; Genes; Goals; Growth; Harvest; Image; Immunofluorescence Immunologic; In Vitro; Inductively Coupled Plasma Mass Spectrometry; Infection; Infectious colitis; Inflammatory Bowel Diseases; Intestinal Diseases; Intestinal Mucosa; Intestines; Investigation; Iron; Knowledge; Length; Link; Microbial Biofilms; Microbiology; Modeling; Mucins; Mucous Membrane; Mucous body substance; Mus; Mutation; Nitrogen Fixation Genes; Nutrient; Pathogenesis; Pathway interactions; Pattern; Pennsylvania; Pentetic Acid; Physiological; Pilum; Play; Proteins; Proteomics; Radial; Research; Research Personnel; Role; Small Intestines; Specificity; Study models; Surface; Techniques; Testing; Universities; Urinary tract; career development; experience; experimental study; fitness; gain of function; gut colonization; gut microbiome; in vivo; inhibitor; innovation; iron supplementation; knowledge base; loss of function; microbial; microbiome analysis; microbiota; mucosal microbiota; murine colitis; mutant; pathogen; rRNA Genes; skills

Project Summary It is well established that biofilms are critical for the pathogenesis of many bacterial infections. More recently, biofilms have also been implicated in the pathogenesis of intestinal diseases such as colorectal cancer and inflammatory bowel disease, where mucosal-associated polymicrobial communities harvested from diseased colon exacerbates disease in animal models. Despite these studies, the presence of biofilms in the intestinal tract has been controversial. Since the mucus that lines the intestinal tract is constantly shed, the ability of this layer to provide a stable surface for biofilm formation has been questioned. There are currently no tractable models to understand or explore biofilm formation in the intestinal environment. As a result, evidence supporting a role for biofilm formation in colonization of the mucosal surface is lacking. In preliminary data, we show that deletion of the E. coli gene ntrC (∆ntrC), which encodes a regulator for nitrogen utilization, results in increased biofilm formation in vitro and confers a 2-3 log competitive advantage over wild-type (WT) E. coli in vivo in mice (despite reduced growth rate in vitro). These results are consistent with a role for biofilm formation in intestinal colonization. I therefore hypothesize that competitive fitness of ∆ntrC E. coli is a reflection of biofilm formation at the mucosal surface of the intestinal tract. The objective is to further characterize the role of biofilm formation in E. coli colonization of the intestinal tract and to use this model system to understand more generally the role of biofilms in disease pathogenesis at the intestinal mucosal interface. This hypothesis will be tested through three inter-related specific aims that will determine the relationship behind biofilm formation in vitro and spatially-localized colonization throughout the murine small intestine and colon (Aim 1), determine the role of iron in E. coli biofilm formation and intestinal colonization (Aim 2), and characterize the biological impact of bacterial biofilm formation in disease pathogenesis using a murine model of colitis (Aim 3). The experiments will use various innovative approaches including the creation and inoculation of genetically- modified E. coli strains, quantification of iron via ICP-MS in the intestinal mucus and lumen, and 16S rRNA gene microbiota sequencing to address these physiologically-relevant mechanisms. The proposed research is significant because it will provide new information about the bacterial determinants of biofilm formation in the intestinal tract, with the rationale of using them for competitive niche exclusion in models of colitis. University of Pennsylvania provides the perfect research environment to conduct this investigation given local expertise in the inter-related fields of gut microbiome and basic microbiology. The candidate will gain experience in compositional and functional analysis of the microbiome, acquire fundamental skills in microbial gene engineering techniques, and broaden her knowledge base of microbiology. These skill sets will greatly enhance the candidate's career development into an independent scientific investigator, with the long-term goal of enabling us to better understand and modulate the effects of the gut microbiome in disease states.

项目总结