Project description:Advanced age is associated with chronic low-grade inflammation, which is usually referred to as inflammaging. Elderly are also known to have an altered gut microbiota composition. However, whether inflammaging is a cause or consequence of an altered gut microbiota composition is not clear. In this study gut microbiota from young or old conventional mice was transferred to young germ-free mice. Four weeks after gut microbiota transfer immune cell populations in spleen, Peyer’s patches, and mesenteric lymph nodes from conventionalized germ-free mice were analyzed by flow cytometry. In addition, whole-genome gene expression in the ileum was analyzed by microarray. Gut microbiota composition of donor and recipient mice was analyzed with 16S rDNA sequencing. Here we show by transferring aged microbiota to young germ-free mice that certain bacterial species within the aged microbiota promote inflammaging. This effect was associated with lower levels of Akkermansia and higher levels of TM7 bacteria and Proteobacteria in the aged microbiota after transfer. The aged microbiota promoted inflammation in the small intestine in the germ-free mice and enhanced leakage of inflammatory bacterial components into the circulation was observed. Moreover, the aged microbiota promoted increased T cell activation in the systemic compartment. In conclusion, these data indicate that the gut microbiota from old mice contributes to inflammaging after transfer to young germ-free mice.
Project description:Maternal secretor status is one of the determinants of human milk oligosaccharides (HMOs) composition, which in turn changes the gut microbiota composition of infants. To understand if this change in gut microbiota impacts immune cell composition, intestinal morphology and gene expression, day 21-old germ-free mice were transplanted with fecal microbiota from infants whose mothers were either secretors (SMM) or non-secretors (NSM) or from infants consuming dairy-based formula (MFM). For each group, one set of mice was supplemented with HMOs. HMO supplementation did not significantly impact the microbiota diversity however, SMM mice had higher abundance of genus Bacteroides, Bifidobacterium, and Blautia, whereas, in the NSM group, there were higher abundance of Akkermansia, Enterocloster, and Klebsiella. In MFM, gut microbiota was represented mainly by Parabacteroides, Ruminococcaceae_unclassified, and Clostrodium_sensu_stricto. In mesenteric lymph node, Foxp3+ T cells and innate lymphoid cells type 2 (ILC2) were increased in MFM mice supplemented with HMOs while in the spleen, they were increased in SMM+HMOs mice. Similarly, serum immunoglobulin A (IgA) was also elevated in MFM+HMOs group. Distinct global gene expression of the gut was observed in each microbiota group, which was enhanced with HMOs supplementation. Overall, our data shows that distinct infant gut microbiota due to maternal secretor status or consumption of dairy-based formula and HMO supplementation impacts immune cell composition, antibody response and intestinal gene expression in a mouse model.
Project description:The aim of this study was to test the hypothesis that replenishing the microbiota with a fecal microbiota transplant (FMT) can rescue a host from an advanced stage of sepsis. We developed a clinically-relevant mouse model of lethal polymicrobial gut-derived sepsis in mice using a 4-member pathogen community (Candida albicans, Klebsiella oxytoca, Serratia marcescens, Enterococcus faecalis) isolated from a critically ill patient. In order to mimic pre-operative surgical patient condition mice were exposed to food restriction and antibiotics. Approximately 18 hours prior to surgery food was removed from the cages and the mice were allowed only tap water. Each mouse received an intramuscular Cefoxitin injection 30 minutes prior to the incision at a concentration of 25 mg/kg into the left thigh. Mice were then subjected to a midline laparotomy, 30% hepatectomy of the left lateral lobe of the liver and a direct cecal inoculation of 200 µL of the four pathogen community. On postoperative day one, the mice were administered rectal enema. Mice were given either 1 ml of fecal microbiota transplant (FMT) or an autoclaved control (AC). This was again repeated on postoperative day two. Mice were then followed for mortality. Chow was restored to the cages on postoperative day two, approximately 45 hours after the operation. The injection of fecal microbiota transplant by enema significantly protected mice survival, reversed the composition of gut microflora and down-regulated the host inflammatory response. The cecum, left lobe of the liver, and spleen were isolated from mice for microarray processing with three or more replicates for six expermental conditions: non-treated control, SAHC POD1, SAHC.AC POD2, SAHC.FMT POD2, SAHC.AC POD7, SAHC.FMT POD7
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:The gut microbiota exerts profound influence on poultry immunity and metabolism through mechanisms that yet need to be elucidated. Here we used conventional and germ-free chickens to explore the influence of the gut microbiota on transcriptomic along the gut-lung axis in poultry. Our results demonstrated a differential regulation of genes associated with innate immunity and metabolism in the spleen of germ-free birds.
Project description:We profiled transcriptome and accessible chromatin landscapes in intestinal epithelial cells (IECs) from mice reared in the presence or absence of microbiota. We show that regional differences in gene transcription along the intestinal tract were accompanied by major alterations in chromatin organization. Surprisingly, we discovered that microbiota modify host gene transcription in IECs without significantly impacting the accessible chromatin landscape. Instead, microbiota regulation of host gene transcription might be achieved by differential expression of specific TFs and enrichment of their binding sites in nucleosome depleted CRRs near target genes. Our results suggest that the chromatin landscape in IECs is pre-programmed by the host in a region-specific manner to permit responses to microbiota through binding of open CRRs by specific TFs. mRNA and accessible chromatin (DNase-seq) profiles from colonic and ileal IECs were compared between conventionally-raised (CR), germ-free (GF), and conventionalized (CV) C57BL/6 mice.
Project description:Gut microbiota comparation of Young mice (n=10), Old mice, Young_yFMT (Young mice 14 days after transplant feces from young mice, n=10) and Young_oFMT (Young mice 14 days after transplant feces from old mice, n=10), Antibiotic group (Cefazolin, n=8).