Project description:We generate B-cell-specific Tlr9-deficient (Tlr9fl/fl/Cd19Cre+/-, KO) B6 mice and model obesity using a high-fat diet. Compared with control mice, B cell Tlr9-deficient mice exhibited increased weight gain, impaired glucose and insulin tolerance, reduced IL-10-producing B cells and increased inflammation in fat tissues. Tlr9 deficiency affected B cell differentiation, immunoglobulin levels, and T cell subsets. Furthermore, altered gut microbiota in B-cell-specific Tlr9-deficient mice led to a pro-inflammatory status in gut associated lymphoid tissues and glucose metabolism dysregulation. Using 16S rRNA sequencing we report altered gut microbial communities in the KO mice. Indeed, a reduction in Lachnospiraceae, may play a key role in the observed metabolic phenotypes in KO mice. Also, We identify an important network involving Tlr9, Irf4 and Il-10.
Project description:The mammalian gut is inhabited by a large and complex microbial community that lives in a mutualistic relationship with its host. Innate and adaptive mucosal defense mechanisms ensure a homeostatic relationship with this commensal microbiota. Secretory antibodies are generated from the active polymeric Ig receptor (pIgR)-mediated transport of IgA and IgM antibodies to the gut lumen and form the first line of adaptive immune defense of the intestinal mucosa. We probed mucosal homeostasis in pIgR knockout (KO) mice, which lack secretory antibodies. We found that in pIgR KO mice, colonic epithelial cells, the cell type most closely in contact with intestinal microbes, differentially expressed (>2-fold change) more than 200 genes compared with wild type mice, and upregulated the expression of anti-microbial peptides in a commensal-dependent manner. Detailed profiling of microbial communities based on 16S rRNA genes revealed differences in the commensal microbiota between pIgR KO and wild type mice. Furthermore, we found that pIgR KO mice showed increased susceptibility to dextran sulfate sodium (DSS)-induced colitis, and that this was driven by their conventional intestinal microbiota. In conclusion, secretory antibodies or the pIgR itself are required to maintain a stable commensal microbiota. In the absence of these humoral effector components, gut homeostasis is disturbed and the outcome of colitis significantly worsened. 4 groups: wild type mice treated with antibiotic (5 replicates), wild type mice left untreated (5 replicates), pIgR KO mice treated with antibiotic (6 replicates), and pIgR KO mice left untreated (6 replicates).
Project description:This experiment was investigating how gut commensal bacteria and intestinal inflammation affect miRNA expression. We analyzed miRNA expression of spleen and intestine from specific pathogen free (SPF) B6 mice, germ-free (GF) B6 mice, and IL-10 knockout mice which have severe colitis by microarray. Thus we have total 6 samples: GF spleen; GF intestines; SPF spleen; SPF intestine; IL-10 KO spleen and IL-10 KO intestine. We directly isolated RNA from whole spleens or intestines without any treatments, and then did microarray analysis.
Project description:Abstract. Background: The cause of ulcerative colitis (UC) is not yet fully understood. Previous research has pointed towards a potential role for mutations in NOD2 in promoting the onset and progression of inflammatory bowel disease (IBD) by altering the microbiota of the gut. However, the relationship between toll-like receptor 4 (TLR4) and gut microbiota in IBD is not well understood. To shed light on this, the interaction between TLR4 and gut microbiota was studied using a mouse model of IBD. Methods: To examine the function of TLR4 signaling in intestinal injury repair, researchers developed Dextran Sulfate Sodium Salt (DSS)-induced colitis and injury models in both wild-type (WT) mice and TLR4 knockout (TLR4-KO) mice. To assess changes in the gut microbiota, 16S rRNA sequencing was conducted on fecal samples from both the TLR4-KO and WT enteritis mouse models. Results: The data obtained depicted a protective function of TLR4 against DSS-induced colitis. The gut microbiota composition was found to vary considerably between the WT and TLR4-KO mice groups as indicated by β-diversity analysis and operational taxonomic units (OTUs) cluster. Statistical analysis of microbial multivariate variables depicted an elevated abundance of Escherichia coli/Shigella, Gammaproteobacteria, Tenerlcutes, Deferribacteres, Enterobacteria, Rikenellaceae, and Proteobacteria in the gut microbiota of TLR4-KO mice, whereas there was a considerable reduction in Bacteroidetes at five different levels of the phylogenetic hierarchy including phylum, class, order, family, and genus in comparison with the WT control. Conclusion: TLR4 may protect intestinal epithelial cells from damage in response to DSS-induced injury by controlling the microbiota in the gut.
Project description:The mammalian gut is inhabited by a large and complex microbial community that lives in a mutualistic relationship with its host. Innate and adaptive mucosal defense mechanisms ensure a homeostatic relationship with this commensal microbiota. Secretory antibodies are generated from the active polymeric Ig receptor (pIgR)-mediated transport of IgA and IgM antibodies to the gut lumen and form the first line of adaptive immune defense of the intestinal mucosa. We probed mucosal homeostasis in pIgR knockout (KO) mice, which lack secretory antibodies. We found that in pIgR KO mice, colonic epithelial cells, the cell type most closely in contact with intestinal microbes, differentially expressed (>2-fold change) more than 200 genes compared with wild type mice, and upregulated the expression of anti-microbial peptides in a commensal-dependent manner. Detailed profiling of microbial communities based on 16S rRNA genes revealed differences in the commensal microbiota between pIgR KO and wild type mice. Furthermore, we found that pIgR KO mice showed increased susceptibility to dextran sulfate sodium (DSS)-induced colitis, and that this was driven by their conventional intestinal microbiota. In conclusion, secretory antibodies or the pIgR itself are required to maintain a stable commensal microbiota. In the absence of these humoral effector components, gut homeostasis is disturbed and the outcome of colitis significantly worsened.
Project description:In this study, we transferred gut microbiota of SS-like autoimmune dry eye disease model mice to conventional B6 mice (NOD-FMT). After the transfer, NOD-FMT mice experienced a dramatic change in the gut microbiomes and showed clinicopathological features of SS, including increased corneal fluorescein staining score, decreased tear production, elevated levels of IL-6 mRNA, decreased levels of MUC5AC mRNA encoding mucin. Additionally, we observed that NOD-FMT mice shared stereotypic B cell receptor (BCR) clonotypes with a much higher frequency compared to control group. B cell clones encoding these stereotypic BCR clonotypes developed and expanded locally in the lacrimal gland, and achieved systemic presence in certain clonotypes.
Project description:L-amino acid oxidase 1 (LAO1) is an enzyme that catalyzes the conversion of L-amino acids to α-keto acids, ammonia, and hydrogen peroxide. Previous studies have shown that offspring fed breast milk from LAO1 knockout (KO) mice show clear differences in gut microbiota composition compared to both wild-type (WT) and LAO1 KO mice. LAO1 KO mice also show impaired hippocampal memory function. The primary objective of this study is to determine how changes in the gut microbiota induced by breast milk in LAO1 KO mice affect the brain development of their offspring. To account for potential effects of endogenous LAO1, foster parents were switched on the day the pups were born, with the mother mice being either WT or LAO1 KO and the pups themselves being LAO1 KO. Hippocampi were collected from these mice at postnatal 10 days of age and microarray analysis was performed to reveal altered gene expression associated with the myelin.
Project description:The mammalian gut harbors a diverse microbial community (gut microbiota) that mainly consists of bacteria. Their combined genomes (the microbiome) provide biochemical and metabolic functions that complement host physiology. Maintaining symbiosis seems to be a key requirement for health as dysbiosis is associated with the development of common diseases. Previous studies indicated that the microbiota and the hostM-bM-^@M-^Ys epithelium signal bidirectional inducing transcriptional responses to fine-tune and maintain symbiosis. However, little is known about the hostM-bM-^@M-^Ys responses to the microbiota along the length of the gut as earlier studies of gut microbial ecology mostly used either colonic or fecal samples. This is of importance as not only function and architecture of the gut varies along its length but also microbial distribution and diversity. Few recent studies have begun to investigate microbiota-induced host responses along the length of the gut. However, these reports used whole tissue samples and therefore do not allow drawing conclusions about specificity of the observed responses. Which cells in the intestinal tissue are responsible for the microbially induced response: epithelial, mesenchymal or immune cells? Where are the responding cells located? Furthermore, the gut microbiota has been implicated in epigenetic regulation of the hostM-bM-^@M-^Ys transcriptional profile. We used using extensive microarray analysis of laser capture microdissection (LCM) harvested ileal and colonic tip and crypt fractions from germ-free mice before and during the time course of colonization with a normal microbiota (on days 1, 3, 5 and 7) to investigate the microbiota-induced transcriptional responses and their kinetics in specific and well-defined cell populations of the hostM-bM-^@M-^Ys epithelium. Ileum and colon segments were dissected from germ-free 10-12 weeks old female C57Bl/6 mice and on day 1, 3, 5 and 7 after colonization, washed and frozen as OCT blocks. Cryosections were prepared from these OCT blocks and tip/crypt fractions isolated using laser capture microdissection. To investigate the microbiota-induced transcriptional responses specific for specific subpopulations of intestinal epithelial cells and their kinetics, tip and crypt fractions of ileal and colonic epithelium of germ-free 10-12 weeks old female C57Bl/6 mice before and during the time course of colonization with a normal microbiota (on days 1, 3, 5 and 7) were harvested using laser capture microdissection and probed in an extensive microarray analysis.
Project description:The mammalian gut harbors a diverse microbial community (gut microbiota) that mainly consists of bacteria. Their combined genomes (the microbiome) provide biochemical and metabolic functions that complement host physiology. Maintaining symbiosis seems to be a key requirement for health as dysbiosis is associated with the development of common diseases. Previous studies indicated that the microbiota and the hostM-bM-^@M-^Ys epithelium signal bidirectional inducing transcriptional responses to fine-tune and maintain symbiosis. However, little is known about the hostM-bM-^@M-^Ys responses to the microbiota along the length of the gut as earlier studies of gut microbial ecology mostly used either colonic or fecal samples. This is of importance as not only function and architecture of the gut varies along its length but also microbial distribution and diversity. Few recent studies have begun to investigate microbiota-induced host responses along the length of the gut. However, these reports used whole tissue samples and therefore do not allow drawing conclusions about specificity of the observed responses. Which cells in the intestinal tissue are responsible for the microbially induced response: epithelial, mesenchymal or immune cells? Where are the responding cells located? We used using extensive microarray analysis of laser capture microdissection (LCM) harvested ileal and colonic tip and crypt fractions from germ-free and conventionally-raised mice to investigate the microbiota-induced transcriptional responses in specific and well-defined cell populations of the hostM-bM-^@M-^Ys epithelium. Ileum and colon segments were dissected from germ-free and conventionally-raised 10-12 weeks old female C57Bl/6 mice, washed and frozen as OCT blocks. Cryosections were prepared from these OCT blocks and tip/crypt fractions isolated using laser capture microdissection. To investigate the microbiota-induced transcriptional responses specific for specific subpopulations of intestinal epithelial cells, tip and crypt fractions of ileal and colonic epithelium of germ-free and conventionally-raised 10-12 weeks old female C57Bl/6 mice were harvested using laser capture microdissection and probed in an extensive microarray analysis.
Project description:We here demonstrate that adiponectin in Paneth cells can suppress renewal and differentiation of gut stem cells through adiponectin receptor 1 (AdipR1). Crypt cells (mainly stem and transit amplifying (TA) cells) in Adipfl/flpVilli-CreT (gut epithelial cell adiponectin conditioned knockout) mice exhibited stronger ability of renewal and differentiation. ScRNA-seq found that there had much more enrichment intestinal stem and TA cells in Adipfl/flpVilli-CreT mice. The renewal and development of gut epithelial cells in irradiated or DSS (dextran sulfate sodium) treated Adipfl/flpVilli-CreT mice was faster than control Adipfl/flp mice. In vitro culture gut organoid of Adipfl/flpVilli-CreT mice exhibited faster growth than those from Adipfl/flp mice. The gut epithelial cells in AdipR1 knockout (KO) mice had much longer crypts than control mice. Interestingly, indole-3-acetic acid (IAA) from gut microbiota could control the expression of adiponectin to promote the renewal and proliferation of gut stem cells. In vitro culture organoid also showed faster development after exposing to IAA. Thus, adiponectin, which is regulated by gut microbiota derived IAA controls the renewal and differentiation of gut stem cells to maintain the homeostasis of epithelial cells.