Project description:Instability in the composition of gut bacterial communities, referred as dysbiosis, has been associated with important human intestinal disorders such as Crohn’s disease and colorectal cancer. Our data showed that Nod2-mediated risk of intestinal inflammation in colitis model is communicable to WT mice by cohousing. Here, we investigated if Nod2-deficient mice microbiota is able to change transcript profiles in Nod2-immunocompetent mice (C57Bl6/J mice) independently of colitis.
Project description:Instability in the composition of gut bacterial communities, referred as dysbiosis, has been associated with important human intestinal disorders such as Crohn’s disease and colorectal cancer. Our data showed that Nod2-mediated risk of intestinal inflammation in colitis model is communicable to WT mice by cohousing. Here, we investigated if Nod2-deficient mice microbiota is able to change transcript profiles in Nod2-immunocompetent mice (C57Bl6/J mice) independently of colitis. Analysis used RNA extracted from colonic mucosa of C57Bl/6J mice co-housed with Nod2-deficient mice and C57Bl/6J mice alone. Direct comparisons of 4 biologicals replicates of C57Bl/6J mice cohoused with Nod2-deficient mice vs C57Bl/6J mice were performed.
Project description:We found that mainstream cigarette smoking (4 cigarettes/day, 5 days/week for 2 weeks using Kentucky Research Cigarettes 3R4F) resulted in >20% decrease in the percentage of normal Paneth cell population in Atg16l1 T300A mice but showed minimal effect in wildtype littermate control mice, indicating that Atg16l1 T300A polymorphism confers sensitivity to cigarette smoking-induced Paneth cell damage. We performed cohousing experiments to test if Paneth cell phenotype is horizontally transmissible as is microbiota. Atg16l1 T300A and littermate controls that were exposed to cigarette smoking were used as microbiota donors, and these donor mice were exposed to smoking for 2 weeks prior to cohousing. Separate groups of Atg16l1 T300A and littermate controls that were not exposed to cigarette smoking were used as microbiota recipients. The microbiota recipients were co-housed with microbiota donors of the same genotype for 4 weeks, during this period the donors continued to be exposed to cigarette smoking. Cigarette smoking was performed using smoking chamber with the dosage and schedule as described above. At the end of the experiment, the fecal microbiota composition was analyzed by 16S rRNA sequencing.
Project description:Besides promoting inflammation by mobilizing lipid mediators, secreted phospholipase A2 group IIA (sPLA2-IIA) prevents bacterial infection by degrading bacterial membranes. Here we show that despite the restricted intestinal expression of sPLA2-IIA in BALB/c mice, its genetic deletion leads to amelioration of cancer and exacerbation of psoriasis in distal skin. Intestinal expression of sPLA2-IIA is reduced after antibiotics treatment or under germ-free conditions, suggesting its upregulation by gut microbiota. Metagenome, transcriptome and metabolome analyses have revealed that sPLA2-IIA deficiency alters the gut microbiota, accompanied by notable changes in the intestinal expression of genes related to immunity and metabolism as well as the levels of various blood metabolites and fecal bacterial lipids, suggesting that sPLA2-IIA contributes to shaping of the gut microbiota. The skin phenotypes in Pla2g2a–/– mice are lost when they are co-housed with littermate wild-type mice, resulting in mixing of the microbiota between the genotypes, or when they are housed in a more stringent pathogen-free facility, where Pla2g2a expression in wild-type mice is low and the gut microbial compositions in both genotypes are nearly identical. Thus, our results highlight a new aspect of sPLA2-IIA as a modulator of gut microbiota, perturbation of which affects distal skin responses.
Project description:Transcriptional analysis of immunological characteristics of petstore mice, C57Bl/6 laboratory mice, and C57Bl/6 laboratory mice cohoused with petstore. We hypothesized that cohousing would confer a basal transcriptional signature of immune activation to laboratory mice from petstore mice. Comparison of these data with existing human adult vs. neonatal PBMC expression profiling data (GSE27272) revealed close concordance of laboratory mice with human neonates, and of cohoused or petstore mice with human adults. Results highlight the impact of environment on the basal immune state and suggest that restoring physiological microbial exposure in laboratory mice could provide a relevant tool for modeling immunological events in free-living organisms, including humans. Total RNA was isolated from PBMC of C57Bl/6 laboratory mice, petstore mice and C57Bl/6 laboratory mice cohoused with petstore mice (at least after 60 days post-cohousing)and transcriptional comparison among 3 groups were performed.
Project description:Background and Aims Interoceptive impacts on the brain triggered by changes in the intestinal microbial ecosystem influence mood-related behaviors such as anxiety and depression. Although changes in the gut microbiome can be driven by genetic mutations in the host, how alterations in the gut microbiome caused by host genetic variations affect behavioral outcomes is not fully understood. To investigate how host genetic variation affects interoceptive responses, we analyzed the gut microbiota and investigated gut–brain interactions in sirtuin 3 (Sirt3)-knockout (KO) mice. Methods We evaluated the composition of the gut microbiome and behavior in Sirt3-KO and wild-type (WT) mice. To distinguish microbiome-driven effects from genetic influences, we conducted cohousing experiments and compared results with heterozygous littermates. Region-specific changes in gene expression in the brain were identified by transcriptomic profiling of the limbic system. We also analyzed metabolites in the nucleus of the solitary tract (NTS) generated by gut microbiome–vagal signaling. The role of the vagus nerve in the gut-brain axis was further examined through vagotomy, alongside comparative choline analysis in both mood disorder patients and mice. Results Mood-related neurobehavioral changes and alterations in synaptic plasticity-related genes in the amygdala and bed nucleus of the stria terminalis (BNST) of Sirt3-KO mice appeared to be dependent on gut microbiome composition. Elevated plasma choline levels in both mood disorder patients and Sirt3-KO mice, together with reduced neurotransmitter-related metabolites (e.g., -aminobutyric acid [GABA] in the NTS), suggested that externalizing behaviors in Sirt3-KO mice are mediated by vagus nerve-dependent gut–brain axis signaling. Consistent with this, vagotomy abolished these changes, including GABA in the NTS, as well as alterations in synaptic plasticity in the amygdala and BNST. Conclusions Our findings suggest the novel finding that an altered gut microbiome caused by a host genetic change, namely a Sirt3 deficiency, is sensed in the NTS of the brain via the vagus nerve, leading to externalizing behaviors.
Project description:Laboratory mice comprise an inexpensive and expeditious model organism for preclinical vaccine testing; however, vaccine immunogenicity often fails to adequately translate to humans. Recent reports indicate that reconstituting physiologic microbial experience to specific pathogen free (SPF) mice induces durable immunological changes that better recapitulate the human immune system. We examined the impact of microbial experience on responses to vaccination after cohousing laboratory mice with pet store mice. We demonstrate that human transcriptional responses to influenza vaccination are better recapitulated in cohoused mice. Induction of humoral responses by vaccination was dampened in cohoused mice and resulted in poor control upon challenge. Additionally, the establishment of protective heterosubtypic T cell immunity was compromised in cohoused mice. In summary, SPF mice exaggerated both humoral and T cell protection induced by influenza vaccines compared to cohoused mice, suggesting that reconstituting microbial experience in laboratory mice through cohousing may better inform preclinical vaccine testing.