Project description:Recent studies in both mice and human have suggested that the gut microbiota could modulate tumor response to chemotherapeutic agents or immunotherapies. However, the underlying mechanism has not been well characterized. Here, we found that disruption of the intestinal microbiota with antibiotics impaired the anti-cancer efficacy of oxaliplatin, which was correlated with the reduction of lots of the intestinal microbial metabolites including butyrate, one of the short chain fatty acids. Re-supplementation of either the whole intestinal microbial metabolites or butyrate could rescue the therapeutic responses of oxaliplatin in the microbiota-destroyed tumor-bearing mice by modulating CD8+ T cell function in the tumor microenvironment. Further experiments showed butyrate boosted the anti-tumor cytotoxic CD8+ T cell responses through ID2, a key transcription regulator highly expressed by tumor-infiltrating CD8+ T cells. Butyrate induced ID2 expression in CD8+ T cells, while ID2 further promoted the proliferation and function of CD8+ T cells through IL-12 signaling. Together, our findings suggest that gut microbial metabolite butyrate could promote the anti-tumor therapeutic efficacy through the ID2-dependent regulation of CD8+ T cell immunity.
Project description:Recent studies in both mice and human have suggested that the gut microbiota could modulate tumor response to chemotherapeutic agents or immunotherapies. However, the underlying mechanism has not been well characterized. Here, we found that disruption of the intestinal microbiota with antibiotics impaired the anti-cancer efficacy of oxaliplatin, which was correlated with the reduction of lots of the intestinal microbial metabolites including butyrate, one of the short chain fatty acids. Re-supplementation of either the whole intestinal microbial metabolites or butyrate could rescue the therapeutic responses of oxaliplatin in the microbiota-destroyed tumor-bearing mice by modulating CD8+ T cell function in the tumor microenvironment. Further experiments showed butyrate boosted the anti-tumor cytotoxic CD8+ T cell responses through ID2, a key transcription regulator highly expressed by tumor-infiltrating CD8+ T cells. Butyrate induced ID2 expression in CD8+ T cells, while ID2 further promoted the proliferation and function of CD8+ T cells through IL-12 signaling. Together, our findings suggest that gut microbial metabolite butyrate could promote the anti-tumor therapeutic efficacy through the ID2-dependent regulation of CD8+ T cell immunity.
Project description:Alterations in intestinal microbiota and intestinal short chain fatty acids profiles have been associated with the pathophysiology of obesity and insulin resistance. Whether intestinal microbiota dysbiosis is a causative factor in humans remains to be clarified We examined the effect of fecal microbial infusion from lean donors on the intestinal microbiota composition, glucose metabolism and small intestinal gene expression. Male subjects with metabolic syndrome underwent bowel lavage and were randomised to allogenic (from male lean donors with BMI<23 kg/m2, n=9) or autologous (reinfusion of own feces, n=9) fecal microbial transplant. Insulin sensitivity and fecal short chain fatty acid harvest were measured at baseline and 6 weeks after infusion. Intestinal microbiota composition was determined in fecal samples and jejunal mucosal biopsies were also analyzed for the host transcriptional response. Insulin sensitivity significantly improved six weeks after allogenic fecal microbial infusion (median Rd: from 26.2 to 45.3 μmol/kg.min, p<0.05). Allogenic fecal microbial infusion increased the overall amount of intestinal butyrate producing microbiota and enhanced fecal harvest of butyrate. Moreover, the transcriptome analysis of jejunal mucosal samples revealed an increased expression of genes involved in a G-protein receptor signalling cascade and subsequently in glucose homeostasis. Lean donor microbial infusion improves insulin sensitivity and levels of butyrate-producing and other intestinal microbiota in subjects with the metabolic syndrome. We propose a model wherein these bacteria provide an attractive therapeutic target for insulin resistance in humans. (Netherlands Trial Register NTR1776).
Project description:Intestinal epithelial cells and the intestinal microbiota are in a mutualistic relationship that is dependent on communication. This communication is multifaceted, but one aspect is communication through compounds produced by the microbiota such as the short-chain fatty acids (SCFAs) butyrate, propionate and acetate. Studying the effects of SCFAs and especially butyrate in intestinal epithelial cell lines like Caco-2 cells has been proven problematic. In contrast to the in vivo intestinal epithelium, Caco-2 cells do not use butyrate as an energy source, leading to a build-up of butyrate. Therefore, we used human induced pluripotent stem cell derived intestinal epithelial cells, grown as a cell layer, to study the effects of butyrate, propionate and acetate on whole genome gene expression in the cells. For this, cells were exposed to concentrations of 1 and 10 mM of the individual short-chain fatty acids for 24 hours. Unique gene expression profiles were observed for each of the SCFAs in a concentration-dependent manner. Evaluation on both an individual gene level and pathway level showed that butyrate induced the biggest effects followed by propionate and then acetate. Several known effects of SCFAs on intestinal cells were confirmed, such as effects on metabolism and immune responses. The changes in metabolic pathways in the intestinal epithelial cell layers in this study demonstrate that there is a switch in energy source from glucose to SCFAs, thus induced pluripotent stem cell derived intestinal epithelial cell are responding in a similar manner to SCFAs as in vivo intestinal tissues.
Project description:Intestinal macrophages were isolated from the intestine of mice that had been administered antibiotics for 7 days, prior to 7 days or re-exposure to the microbiota (recolonisation). In some experiments, the short-chain fatty acid butyrate was administered alongside antibiotics prior to recolonisation.
Project description:Dry eye is a common ocular inflammatory disorder characterized by tear film instability and reduced tear production. There is increasing evidence that homeostasis of the ocular surface is impacted by the intestinal microbiome. We are interested in investigating the potential role of microbially produced small molecules in mediating the interaction between the intestinal microbiota and the ocular surface. One such molecule is butyrate, a short-chain fatty acid (SCFA) produced by certain members of the gut microbiota through fermentation of dietary fiber. We have shown that oral administration of tributyrin, a prodrug form of butyrate, is protective of the ocular surface in mice undergoing desiccating stress. To gain insight into the mechanism, we analyzed gene expression in conjunctival tissue from mice treated with either tributyrgn or vehicle control.
Project description:Background: Humans with metabolic and inflammatory diseases frequently harbor lower levels of butyrate-producing bacteria in their gut. However, it is not known whether variation in the levels of these organisms is causally linked with disease development and whether diet modifies the impact of these bacteria on health. Results: We use germ-free apolipoprotein E-deficient mice colonized with synthetic microbial communities that differ in their capacity to generate butyrate to demonstrate that Roseburia intestinalis interacts with dietary components to (i) impact gene expression in the intestine, directing metabolism away from glycolysis and toward fatty acid utilization, (ii) improve intestinal barrier function, (iii) lower systemic inflammation and (iv) ameliorate atherosclerosis. Furthermore, intestinal administration of butyrate improves gut barrier function and reduces atherosclerosis development. Conclusions: Altogether, our results illustrate how modifiable diet-by-microbiota interactions impact cardiovascular disease, and suggest that interventions aimed at increasing the representation of butyrate-producing bacteria may provide protection against atherosclerosis.
Project description:Several aspects common to a Western lifestyle, including obesity and decreased physical activity, are known risks for gastrointestinal cancers. There is an increasing amount of evidence suggesting that diet profoundly affects the composition of the intestinal microbiota. Moreover, there is now unequivocal evidence linking a dysbiotic gut to cancer development. Yet, the mechanisms through which high-fat diet (HFD)-mediated changes in the microbial community impact the severity of tumorigenesis in the gut, remain to be determined. Here we demonstrate that HFD promotes tumor progression in the small intestine of genetically susceptible K-rasG12Dint mice independent of obesity. HFD consumption in conjunction with K-Ras mutation mediates a shift in the composition of gut microbiota, which is associated with a decrease in Paneth cell antimicrobial host defense that compromises dendritic cell (DC) recruitment and MHC-II presentation in the gut-associated lymphoid tissues (GALTs). DC recruitment in GALTs can be normalized, and tumor progression attenuated completely, when K-rasG12Dint mice are supplemented with the short-chain fatty acid butyrate, a bacterial fermentation endproduct. Importantly, Myd88-deficiency completely blocks tumor progression in K-rasG12Dint mice. Transfer of fecal samples from diseased donors into healthy adult K-rasG12Dint mice is sufficient to transmit disease in the absence of HFD. Furthermore, treatment with antibiotics completely blocks HFD-induced tumor progression, suggesting a pivotal role for distinct microbial shifts in aggravating disease in the small intestine. Collectively, these data underscore the importance of the reciprocal interaction between host and environmental factors in selecting intestinal microbiota that favor carcinogenesis, and suggest tumorigenesis may be transmissible among genetically predisposed individuals. 3 mice each for each treatment.
Project description:Early-life antibiotic exposure perturbs the intestinal microbiota, alters innate intestinal immunity, and accelerates type 1 diabetes development in the NOD mouse model. Here we found that maternal cecal microbiota transfer (CMT) to NOD mice with early-life antibiotic perturbation partially rescued the induced T1D acceleration. The restoration effects on the intestinal microbiome were substantial and persistent, remediating the antibiotic-depleted diversity, relative abundance of particular taxa, and metabolic pathways. CMT also protected against perturbed cecal and serum metabolites and normalized innate and adaptive immune effectors. CMT restored patterns of ileal microRNA and histone regulation of gene expression and exon-splicing. Based on the analyses of experimental data, we propose an innate intestinal immune network involving CD44, TLR2, and Reg3g, as well as their multiple microRNA and epigenetic regulators that sense intestinal signaling by the gut microbiota. This regulation affects downstream immunological tone, leading to protection against the tissue-specific T1D injury.
Project description:Upon tamoxifen induced recombination, Villin-CreERT2+ Lsd1fl/fl (icKO) mice develop an immature intestinal epithelium characterized by an incomplete differentiation of enterocytes and secretory lineages, reduced number of goblet cells and a complete loss of Paneth cells. The main goal of this experiment was to test whether maturation of intestinal epithelium affects microbiota establishment and development. In addition, this loss of differentiated cell types after Lsd1 recombination is gradual and dependent on renewal times of each specific cell type (i.e. enterocytes take less than a week to be fully replenished while Paneth cells cycle around every 4 weeks). Hence by collecting stool from the same mouse at different time points after tamoxifen induced recombination a relationship between loss of particular cell types and changes in bacterial populations can be established. In addition, we wanted to test whether maturation of intestinal epithelium affects microbiota establishment and development