Bacterial surface layer-specific immune protection against gut microbial infection

针对肠道微生物感染的细菌表面层特异性免疫保护

基本信息

批准号：
9119312
负责人：
Mansour M Zadeh
金额：
$ 35.07万
依托单位：
UNIVERSITY OF FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-05-01 至 2020-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9119312
关键词：
Ablation Acyltransferase Affect Affinity Amino Acids Animal Model Antigens Bacteria Bacterial Proteins Binding Butyrates C-Type Lectins Catabolism Cell Differentiation process Cells Chronic Disease Colitis Communities Data Dendritic Cells Development Disease Progression Equilibrium Exhibits Feces Genes Germ-Free Health Heat shock proteins Homeostasis Human Human Milk Immune Immune response Immunity Infection Inflammation Inflammatory Interleukin-1 beta Intestinal Diseases Intestinal Mucosa Intestines Invaded Kynurenine Laboratories Lymphocyte antigen CD50 Maintenance Mediating Microbe Modeling Mono-S Mus Newborn Infant Nutritional Outcome Pathologic Pathology Peptides Peripheral Physiological Play Premature Infant Probiotics Propionibacterium Protein S Proteins Regulation Regulatory T-Lymphocyte Research Proposals Role Sequence Analysis Sequence Homology Shapes Signal Transduction Surface T-Lymphocyte Subsets Testing Tissues Tryptophan adaptive immunity cell mediated immune response cytokine feeding fitness gastrointestinal infection gene product genome sequencing gut microbiota improved insight microbial microbiota mouse model novel pathogen pathogenic bacteria prevent public health relevance receptor response

项目摘要

DESCRIPTION (provided by applicant): Efficacious protective and controlled immunity against gastrointestinal (GI) infection requires critical regulatory signals induced by a balanced gut microbiota and associated metabolites resulting in functional homeostasis that prevents the manifestation of pathologic intestinal disorders. We demonstrated that human breast milk, when compared to formula given to preterm infants, critically reshapes the gut microbial composition and increases beneficial bacteria genera (e.g., Propionibacterium). First draft genome-sequence analysis of one of these newly identified probiotic strains, tentatively designated, P. UF1, is closely related to, and yet distinct, (85% sequence homology) from known Propionibacterium species, including P. freudenreichii. Obtained data demonstrate that P. UF1 significantly governs the regulation of induced inflammatory cytokines (e.g., IL-1β) in germ-free (GF) mice transfaunated with imbalanced microbiota derived from the feces of formula-fed preterm infants. P. UF1 not only regulated Th17 responses against pathogen infection, but also fortified the intestinal mucosal barrier function. Such immune regulation is tightly controlled by the surface layer (S-layer) of the bacterium binding to specific intercellular adhesion molecule-3-grabbing nonintegrin-related 1 (SIGNR1) expressed by colonic dendritic cells (DCs), resulting in S-layer-specific Th17 differentiation. This homeostasis significantly deteriorated in Signr1-/- mice, further emphasizing the crucial role of this molecular interaction in protective gut immunity. Th17 formation was significantly ablated in H2-Ab1-/- (MHC II-/) mice, suggesting S- layer-dependent Th17 differentiation. Mono-associated GF-mice given P. UF1 exhibited specifically Th17 differentiation and key metabolites (e.g., kynurenine) involved in tryptophan catabolism that regulates Th17 function. Additionally, the dihydrolipoamide acyltransferase (dlaT) gene was deleted in P. UF1 designated, ΔdlaT P. UF1, to elucidate the role of this critically important S-layer component in S-layer-specific Th17 differentiation, intestinal microbial composition, and related induced metabolites. Preliminary data strongly indicate that ablation of the dlaT gene in P. UF1 fundamentally diminishes the regulatory function of this bacterium to control induced gut proinflammation (e.g., IL-1β). The objective of this research proposal is to clearly delineate the role of the S-layer of P. UF1 in the induction of regulated protective S-layer-specific Th17 responses against intestinal infection. Thus, we hypothesize that the newly identified P. UF1 species not only induces S-layer-specific Th17 differentiation upon interaction with SIGNR1 to confer protection against pathogens, but that the bacterial S-layer dlaT gene is significantly involved in these antigen-specific Th17 responses. The Specific Aims are: 1) Elucidate S-layer-specific Th17 differentiation and its regulation by SIGNR1 signaling, and 2) Delineate the critical involvement of bacterial dihydrolipoamide acyltransferase (DlaT) in S-layer-specific Th17 differentiation. Such mechanistic insights will unravel integral mechanisms involved in the regulation of induced protective S-layer-specific immune responses against pathogen infection.

描述（由申请人提供）：针对胃肠道（GI）感染的有效保护性和受控免疫力需要由平衡的肠道微生物群和相关代谢物诱导的关键调节信号，从而产生功能性稳态，从而防止病理性肠道疾病的表现。与早产儿配方奶粉相比，它显着重塑了肠道微生物组成并增加了有益菌属（例如丙酸杆菌）。对这些新鉴定的益生菌菌株之一（暂定名为 P. UF1）的基因组序列分析与已知的丙酸杆菌属物种（包括费氏丙酸杆菌）密切相关，但又不同（85% 序列同源性）。在无菌 (GF) 小鼠中，UF1 显着控制诱导炎症细胞因子（例如 IL-1β）的调节，这些小鼠的微生物群不平衡配方奶喂养的早产儿的粪便中，P. UF1不仅调节Th17针对病原体感染的反应，而且还增强了肠粘膜屏障功能，这种免疫调节受到与细菌结合的表面层（S层）的严格控制。结肠树突状细胞 (DC) 表达的特异性细胞间粘附分子 3 抓取非整合素相关 1 (SIGNR1)，导致 S 层特异性Signr1-/- 小鼠中的 Th17 分化显着恶化，进一步强调了这种分子相互作用在保护性肠道免疫中的关键作用。 H2-Ab1-/- (MHC II-/) 小鼠中的形成显着消除，表明给予 P 的 Mono 相关 GF 小鼠出现 S 层依赖性 Th17 分化。UF1 显示 Th17 分化，特别是关键代谢物（例如犬尿氨酸）。参与调节 Th17 功能的色氨酸分解代谢此外，二氢硫辛酰胺酰基转移酶 (dlaT) 基因在 P. UF1 命名为 ΔdlaT P. UF1，以有力地阐明这一至关重要的 S 层成分在 S 层特异性 Th17 分化、肠道微生物组成和相关诱导代谢物中的作用。初步数据表明，P 中 dlaT 基因的消除。 UF1 从根本上削弱了这种细菌控制诱导的肠道促炎症（例如 IL-1β）的调节功能。是为了明确界定 P. UF1 的 S 层在诱导针对肠道感染的受调节的 S 层特异性 Th17 反应中的作用因此，我们发现新鉴定的 P. UF1 物种不仅诱导 S 层特异性 Th17 分化。与 SIGNR1 相互作用以提供针对病原体的保护，但细菌 S 层 dlaT 基因显着参与这些抗原特异性 Th17 反应。具体目标是：1) 阐明 S 层特异性。 Th17 分化及其通过 SIGNR1 信号传导的调节，以及 2) 描绘关键细菌二氢硫辛酰胺酰基转移酶 (DlaT) 参与 S 层特异性 Th17 分化，这种机制见解将揭示参与调节诱导的 S 层特异性免疫应答以抵抗病原体感染的整体机制。