Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1094948 | ENA |
REPOSITORIES: ENA
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Project description:Commensal bacteria are crucial in maintaining host physiological homeostasis, immune system development, and protection against pathogens. Despite their significance, the factors influencing persistent bacterial colonization and their impact on the host still need to be fully understood. Animal models have served as valuable tools to investigate these interactions, but most have limitations. The bacterial genus Neisseria, which includes both commensal and pathogenic species, has been studied from a pathogenicity to humans’ perspective, but lacks models that study immune responses in the context of long-term persistence. Neisseria musculi, a recently described natural commensal of mice, offers a unique opportunity to study long-term host-commensal interactions. In this study, for the first time we have used this model to study the transcriptional, phenotypic, and functional dynamics of immune cell signatures in the mucosal and systemic tissue of mice in response to Neisseria musculi colonization. We found key genes and pathways vital for immune homeostasis in palate tissue, validated by flow cytometry of immune cells from lung, blood and spleen. This study offers a novel avenue for advancing our understanding of host-bacteria dynamics and may provide a platform for developing efficacious interventions against mucosal persistence by pathogenic Neisseria.
2024-05-16 | GSE267528 | GEO
Project description:The microbiome is an important immune regulator, but the mechanisms by which commensal microbes shape systemic host defense during bloodstream infection remain poorly defined and commonly used pre-clinical models have practical, ethical and scientific limitations. Here, we establish a gnotobiotic zebrafish larval model to investigate microbiome-dependent protection against systemic blood infection by E. coli bacteria, an important cause of early onset neonatal sepsis and nontuberculous mycobacteria to investigate the contribution of Toll-like receptor 2 (TLR2) in the defense responses. Germ-free (GF) and conventionalized (CONVD) larvae derived from the same clutches were systemically infected with E. coli, revealing that microbiome colonization significantly reduces early mortality. RNA-seq revealed a conserved core immune activation program in both GF and CONVD larvae, but the absence of a microbiome was associated with a broader transcriptional response and stronger repression of metabolic pathways, suggesting that commensal microbes buffer infection-induced metabolic suppression. Extending this framework to nontuberculous mycobacteria, we performed systemic infections with fluorescent Mycobacterium marinum and M. avium in tlr2 wild-type and mutant larvae under GF and CONVD conditions. While survival was largely unchanged, imaging-based quantification demonstrated increased bacterial proliferation in tlr2 mutants and in GF larvae, with microbiome-mediated restriction of bacterial burden evident in wild-type but not tlr2-deficient hosts. Together, these data show that microbiome colonization buffers septic outcomes by reshaping systemic inflammatory and metabolic programs, and identify TLR2 as a key node linking microbial colonization to effective host defense during nontuberculous mycobacterial infection
2026-03-24 | GSE325739 | GEO
Project description:Here we directly compare for the first time how the longstanding static model of mouse Dentate Gyrus (DG) development compares with a comprehensive high-resolution live-cell multiphoton (live-MPM) imaging approach. We took advantage of multiple fluorescent protein-based cell-type specific reporters to identify Neural Stem Cells (NSC), Intermediate Neurogenic Progenitors (INPs), and Granule Neurons (GNs) to generate live 4D cellular datasets across embryonic, postnatal and adult ages. Live-MPM revealed that INPs and NSCs migrated long distances along multiple routes to seed the SGZ from multiple directions, and from mosaic progenitor zones along the septo-temporal axis of the hippocampus. We found that dynamic INPs processes and interactions contributed to the architecture of both transient and permanent NSC niches during embryonic development, and that INP cellular plasticity is maintained in the adult SGZ NSC niche. We also used a Molecular Systems (MS) approach to determine the basis for maintained INP cellular plasticity that revealed an overlapping signaling network infrastructure based largely on Rho-family mediated regulation of cytoskeletal dynamics. Our combined strategies revealed that dynamic INPs are a major molecular signaling transition state in the adult SGZ, and that Tbr2 expression defines the initial stage of GN commitment. Our novel findings reveal fundamental new insight into one of the most well studied brain regions key for normal cognitive function, and the importance of analyzing the development of live stem cell niches in vivo. In concert with live-cell imaging, we used microarray analysis to identify genes that may be involved in the development of the Dentate Gyrus NSC niche.
2014-08-01 | E-GEOD-50148 | biostudies-arrayexpress
Project description:The gastrointestinal tract of mammals is inhabited by hundreds of distinct species of commensal microorganisms that exist in a mutualistic relationship with the host. The process by which the commensal microbiota influence the host immune system is poorly understood. We show here that colonization of the small intestine of mice with a single commensal microbe, segmented filamentous bacterium (SFB), is sufficient to induce the appearance of CD4+ T helper cells that produce IL-17 and IL-22 (Th17 cells) in the lamina propria. SFB adhere tightly to the surface of epithelial cells in the terminal ileum of mice with Th17 cells but are absent from mice that have few Th17 cells. Colonization with SFB was correlated with increased expression of genes associated with inflammation, anti-microbial defenses, and tissue repair, and resulted in enhanced resistance to the intestinal pathogen Citrobacter rodentium. Control of Th17 cell differentiation by SFB may thus establish a balance between optimal host defense preparedness and potentially damaging T cell responses. Manipulation of this commensal-regulated pathway may provide new opportunities for enhancing mucosal immunity and treating autoimmune disease. Experiment Overall Design: We compared the gene expression profiles in the terminal ileum of Swiss-Webster GF mice before and after colonization with SFB, which induced robust Th17 cell differentiation. To sieve out host effects, the role of other microbiota, as well as other factors, we also evaluated the transcriptional program induced in Jackson C57BL/6 mice after co-housing with Taconic B6 animals, which also induces Th17 cell differentiation. 0.5 cm of the most distal part of the small intestine was dissected. Total RNA was extracted with TRIzol. RNA was labeled and hybridized to GeneChip Mouse Genome 430 2.0 arrays following the Affymetrix protocols. Data were analyzed in GeneSpring GX10.
2009-11-10 | E-GEOD-18348 | biostudies-arrayexpress
Project description:The gastrointestinal tract of mammals is inhabited by hundreds of distinct species of commensal microorganisms that exist in a mutualistic relationship with the host. The process by which the commensal microbiota influence the host immune system is poorly understood. We show here that colonization of the small intestine of mice with a single commensal microbe, segmented filamentous bacterium (SFB), is sufficient to induce the appearance of CD4+ T helper cells that produce IL-17 and IL-22 (Th17 cells) in the lamina propria. SFB adhere tightly to the surface of epithelial cells in the terminal ileum of mice with Th17 cells but are absent from mice that have few Th17 cells. Colonization with SFB was correlated with increased expression of genes associated with inflammation, anti-microbial defenses, and tissue repair, and resulted in enhanced resistance to the intestinal pathogen Citrobacter rodentium. Control of Th17 cell differentiation by SFB may thus establish a balance between optimal host defense preparedness and potentially damaging T cell responses. Manipulation of this commensal-regulated pathway may provide new opportunities for enhancing mucosal immunity and treating autoimmune disease.
2009-10-22 | GSE18348 | GEO
Project description:Host pathways mediating changes in immune states elicited by intestinal microbial colonization are incompletely characterized. Here we describe alterations of the host immune state induced by colonization of germ-free zebrafish larvae with an intestinal microbial community or single bacterial species. We show that microbiota-induced changes in intestinal leukocyte subsets and whole-body host gene expression are dependent on the innate immune adaptor gene myd88. Similar patterns of gene expression are elicited by colonization with conventional microbiome, as well as mono-colonization with two different zebrafish commensal bacterial strains. By studying loss-of-function myd88 mutants, we find that colonization suppresses Myd88 at the mRNA level. Tlr2 is essential for microbiota-induced effects on myd88 transcription and intestinal immune cell composition.
2018-10-05 | GSE82200 | GEO