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

• 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
• 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

 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（由申请方提供）：针对胃肠道（GI）感染的有效保护性和受控免疫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，从而导致功能性稳态，防止病理性肠道疾病的表现。我们证明，与给予早产儿的配方奶粉相比，人类母乳严重重塑了肠道微生物组成，并增加了有益细菌属（例如，丙酸杆菌属）。这些新鉴定的益生菌菌株之一的基因组序列分析的第一个草案，暂时命名为P.UF1，与已知的丙酸杆菌属物种密切相关，但又不同（85%序列同源性），包括费氏丙酸杆菌。获得的数据表明，P.UF1显著地支配诱导的炎性细胞因子（例如，IL-1β）在无菌（GF）小鼠中的作用，这些小鼠的菌群来自配方奶粉喂养的早产儿的粪便。UF 1不仅调节Th 17细胞对病原体感染的应答，而且还增强了肠粘膜屏障功能。这种免疫调节是由细菌的表面层（S层）与结肠树突状细胞（DC）表达的特异性细胞间粘附分子-3-抓取非整联蛋白相关1（SIGNR 1）结合而紧密控制的，从而导致S层特异性Th 17分化。这种稳态在Signr 1-/-小鼠中显著恶化，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。Th17 在H2-Ab 1-/-（MHCII-/）小鼠中，Th 17的形成被显著消除，表明S层依赖性Th 17分化。给予P.UF1的单一相关GF-小鼠特异性地表现出Th 17分化和关键代谢物（例如，犬尿氨酸）参与色氨酸催化剂，调节Th 17功能。此外，在P. UF 1中删除了二氢硫辛酰胺酰基转移酶（dlaT）基因，命名为ΔdlaT P. UF 1，以阐明这种至关重要的S层组分在S层特异性Th 17分化、肠道微生物组成和相关诱导代谢物中的作用。初步数据强烈表明，P.UF1中dlaT基因的消除从根本上减少了该细菌控制诱导的肠道促炎症的调节功能（例如，IL-1β）。本研究建议的目的是明确界定 P.UF1的S层在诱导调节的保护性S层特异性Th 17应答对抗肠道感染中的作用。因此，我们假设新鉴定的P.UF1物种不仅在与SIGNR 1相互作用后诱导S层特异性Th 17分化以提供针对病原体的保护，而且细菌S层dlaT基因显著参与这些抗原特异性Th 17应答。具体目的是：1）阐明S层特异性Th 17分化及其通过SIGNR 1信号传导的调节，和2）描绘关键的Th 17分化。 细菌二氢硫辛酰胺酰基转移酶（DlaT）参与S层特异性Th 17分化。这种机制的见解将解开整体机制参与的诱导保护性S-层特异性免疫反应对病原体感染的调节。