Project description:Early life exposure to antibiotics alters the gut microbiome. These alterations lead to changes in metabolic homeostasis and an increase in host adiposity. We used microarrays to identify metabolic genes that may be up- or down-regulated secondary to antibiotic exposure. Low dose antibiotics have been widely used as growth promoters in the agricultural industry since the 1950’s, yet the mechanisms for this effect are unclear. Because antimicrobial agents of different classes and varying activity are effective across several vertebrate species, we hypothesized that such subtherapeutic administration alters the population structure of the gut microbiome as well as its metabolic capabilities. We generated a model of adiposity by giving subtherapeutic antibiotic therapy (STAT) to young mice and evaluated changes in the composition and capabilities of the gut microbiome. STAT administration increased adiposity in young mice and altered hormones related to metabolism. We observed substantial taxonomic changes in the microbiome, changes in copies of key genes involved in the metabolism of carbohydrates to short-chain fatty acids (SCFA), increases in colonic SCFA levels, and alterations in the regulation of hepatic metabolism of lipids and cholesterol. In this model, we demonstrate the alteration of early life murine metabolic homeostasis through antibiotic manipulation. C57BL6 mice were divided into low-dose penicillin or control groups. Given antibiotics via drinking water after weaning. Sacrificed and liver sections collected for RNA extraction.
Project description:The human gut is colonized by trillions of microorganisms that influence human health and disease through the metabolism of xenobiotics, including therapeutic drugs and antibiotics. The diversity and metabolic potential of the human gut microbiome have been extensively characterized, but it remains unclear which microorganisms are active and which perturbations can influence this activity. Here, we use flow cytometry, 16S rRNA gene sequencing, and metatranscriptomics to demonstrate that the human gut contains distinctive subsets of active and damaged microorganisms, primarily composed of Firmicutes, which display marked temporal variation. Short-term exposure to a panel of xenobiotics resulted in significant changes in the physiology and gene expression of this active microbiome. Xenobiotic-responsive genes were found across multiple bacterial phyla, encoding novel candidate proteins for antibiotic resistance, drug metabolism, and stress response. These results demonstrate the power of moving beyond DNA-based measurements of microbial communities to better understand their physiology and metabolism. RNA-Seq analysis of the human gut microbiome during exposure to antibiotics and therapeutic drugs.
Project description:We used microarrays to investigate gene expression changes in leukemic cells from Pax5+/- mice treated with antibiotics. Precursor B cell acute lymphoblastic leukemia (pB-ALL), the most common type of childhood leukemia, is frequently characterized by the cooperation of a genetic predisposition acquired in utero and secondary oncogenic events taking place only in a fraction of predisposed children after birth. Although predisposition can be detected at birth, it is currently unknown which factors determine the development of overt leukemia in genetic carriers and how this can be potentially prevented. Experimental studies have shown that infectious stimuli promote disease onset in genetically predisposed mice. Here, we analyzed the impact of the microbiome on leukemogenesis in a mouse model (Pax5+/- mice) that faithfully mimicks genetic predisposition and leukemogenesis of human pB-ALL related to the synergy of genetic predisposition and exposure to a natural infectious environment. Employing 16S rRNA sequencing and machine learning we can accurately predict a distinct gut microbiome which is determined by a specific constitutional genetic variant. Deprivation of the gut microbiome by antibiotic treatment enhanced pB-ALL development in Pax5+/- predisposed (63% vs. 22%) but not in wildtype mice (0%). This finding was observed in the presence but also -to a lesser extent- in the absence of a natural, infectious environment (48%). The composition of the gut microbiome constitutes a biomarker signature and allows to identify specifically those Pax5+/- mice that developed leukemia. This indicates that the gut microbiome can be used to identify carriers at risk to develop leukemia and to reduce this risk by early-life interventions.
Project description:Exposure to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development and dog-ownership is associated with a distinct house dust microbial exposure. Here we demonstrate, using murine models, that exposure of mice toM-BM- dog-associated house dust protects against ovalbumin or cockroach allergen mediated airway pathology. Protected animals exhibited significant reductions in the total number of airway T cells, down-regulation of Th2-related airway responses as well as mucin secretion. Following house dust exposure, the cecal microbiome of protected animals was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. Supplementation of wild type animals with L. johnsonii protected them against both airway allergen challenge or infection with respiratory syncytial virus. L. johnsonii mediated protection wasM-BM- associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells, as well as significantly reduced airway Th2 cytokine expression. Our results reveal that exposure to dog-associated household dust results in protection against airway allergen challenge and a distinct GI microbiome composition. Moreover the study identifies L. johnsonii as a pivotal species within the gastrointestinal tract capable of influencing adaptive immunity at remote mucosal surfaces in a manner that is protective against a variety of respiratory insults. The G2 PhyloChip microarray platform (commercially available from Second Genome, Inc.) was used to profile cecal gut bacteria from 29 mice: 7 controls, 5 gavaged with dust from homes with pets, 5 gavaged with dust from homes with no pets, 4 CRA-challenged, 4 gavaged with L. johnsonii, and 4 gavaged with L. johnsonii prior to CRA challenge. The PhyloChip was also used to profile 1 house dust sample collected from a home with dogs
Project description:Exposure to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development and dog-ownership is associated with a distinct house dust microbial exposure. Here we demonstrate, using murine models, that exposure of mice toM-BM- dog-associated house dust protects against ovalbumin or cockroach allergen mediated airway pathology. Protected animals exhibited significant reductions in the total number of airway T cells, down-regulation of Th2-related airway responses as well as mucin secretion. Following house dust exposure, the cecal microbiome of protected animals was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. Supplementation of wild type animals with L. johnsonii protected them against both airway allergen challenge or infection with respiratory syncytial virus. L. johnsonii mediated protection wasM-BM- associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells, as well as significantly reduced airway Th2 cytokine expression. Our results reveal that exposure to dog-associated household dust results in protection against airway allergen challenge and a distinct GI microbiome composition. Moreover the study identifies L. johnsonii as a pivotal species within the gastrointestinal tract capable of influencing adaptive immunity at remote mucosal surfaces in a manner that is protective against a variety of respiratory insults. The G2 PhyloChip microarray platform (commercially available from Second Genome, Inc.) was used to profile cecal gut bacteria from 29 mice: 7 controls, 5 gavaged with dust from homes with pets, 5 gavaged with dust from homes with no pets, 4 CRA-challenged, 4 gavaged with L. johnsonii, and 4 gavaged with L. johnsonii prior to CRA challenge. The PhyloChip was also used to profile 1 house dust sample collected from a home with dogs
Project description:Exposure to dogs in early infancy has been shown to reduce the risk of childhood allergic disease development and dog-ownership is associated with a distinct house dust microbial exposure. Here we demonstrate, using murine models, that exposure of mice toM-BM- dog-associated house dust protects against ovalbumin or cockroach allergen mediated airway pathology. Protected animals exhibited significant reductions in the total number of airway T cells, down-regulation of Th2-related airway responses as well as mucin secretion. Following house dust exposure, the cecal microbiome of protected animals was extensively restructured with significant enrichment of, amongst others, Lactobacillus johnsonii. Supplementation of wild type animals with L. johnsonii protected them against both airway allergen challenge or infection with respiratory syncytial virus. L. johnsonii mediated protection wasM-BM- associated with significant reductions in the total number and proportion of activated CD11c+/CD11b+ and CD11c+/CD8+ cells, as well as significantly reduced airway Th2 cytokine expression. Our results reveal that exposure to dog-associated household dust results in protection against airway allergen challenge and a distinct GI microbiome composition. Moreover the study identifies L. johnsonii as a pivotal species within the gastrointestinal tract capable of influencing adaptive immunity at remote mucosal surfaces in a manner that is protective against a variety of respiratory insults. The G2 PhyloChip microarray platform (commercially available from Second Genome, Inc.) was used to profile cecal gut bacteria from 29 mice: 7 controls, 5 gavaged with dust from homes with pets, 5 gavaged with dust from homes with no pets, 4 CRA-challenged, 4 gavaged with L. johnsonii, and 4 gavaged with L. johnsonii prior to CRA challenge. The PhyloChip was also used to profile 1 house dust sample collected from a home with dogs
Project description:Early life exposure to antibiotics alters the gut microbiome. These alterations lead to changes in metabolic homeostasis and an increase in host adiposity. We used microarrays to identify metabolic genes that may be up- or down-regulated secondary to antibiotic exposure. Low dose antibiotics have been widely used as growth promoters in the agricultural industry since the 1950’s, yet the mechanisms for this effect are unclear. Because antimicrobial agents of different classes and varying activity are effective across several vertebrate species, we hypothesized that such subtherapeutic administration alters the population structure of the gut microbiome as well as its metabolic capabilities. We generated a model of adiposity by giving subtherapeutic antibiotic therapy (STAT) to young mice and evaluated changes in the composition and capabilities of the gut microbiome. STAT administration increased adiposity in young mice and altered hormones related to metabolism. We observed substantial taxonomic changes in the microbiome, changes in copies of key genes involved in the metabolism of carbohydrates to short-chain fatty acids (SCFA), increases in colonic SCFA levels, and alterations in the regulation of hepatic metabolism of lipids and cholesterol. In this model, we demonstrate the alteration of early life murine metabolic homeostasis through antibiotic manipulation.
Project description:The gut microbiome is a malleable microbial community that can remodel in response to various factors, including diet, and contribute to the development of several chronic diseases, including atherosclerosis. We devised an in vitro screening protocol of the mouse gut microbiome to discover molecules that can selectively modify bacterial growth. This approach was used to identify cyclic D,L-α-peptides that remodeled the Western diet (WD) gut microbiome toward the low-fat-diet microbiome state. Daily oral administration of the peptides in WD-fed LDLr-/- mice reduced plasma total cholesterol levels and atherosclerotic plaques. Depletion of the microbiome with antibiotics abrogated these effects. Peptide treatment reprogrammed the microbiome transcriptome, suppressed the production of pro-inflammatory cytokines (including interleukin-6, tumor necrosis factor-α and interleukin-1β), rebalanced levels of short-chain fatty acids and bile acids, improved gut barrier integrity and increased intestinal T regulatory cells. Directed chemical manipulation provides an additional tool for deciphering the chemical biology of the gut microbiome and might advance microbiome-targeted therapeutics.
Project description:Erythromycin (ERY) is a commonly used antibiotic that can be found in wastewater effluents globally. Due to the mechanisms by which they kill and prevent bacterial growth, antibiotics can have significant unwanted impacts on the fish gut microbiome. The overall objective of this project was to assess the effects of erythromycin and an antibiotic mixture on fish gut microbiomes. The project was split into two experiments to assess gut microbiome in response to exposure with ERY alone or in mixture with other common antibiotics. The objectives of experiment 1 were to understand uptake and depuration of ERY in juvenile rainbow trout (RBT) over a 7 d uptake followed by a 7 d depuration period using three concentrations of ERY. Furthermore, throughout the study changes in gut microbiome response were assessed. In experiment 2, a follow-up study was conducted using an identical experimental design to assess the impacts of an antibiotic-mixture (ERY, ampicillin, metronidazole, and ciprofloxacin at 100 µg/g each). Here, three matrices were analyzed, with gut collected for 16s metabarcoding, plasma for untargeted metabolomics, and brain for mRNA-seq analysis. ERY was depurated from the fish relatively quickly and gut microbiome dysbiosis was observed at 7 d after exposure, with a slight recovery after the 7 d depuration period. A greater number of plasma metabolites was dysregulated at 14 d compared to 7 d revealing temporality compared to gut microbiome dysbiosis. Furthermore, several transformation products of antibiotics and biomarker metabolites were observed in plasma due to antibiotic exposure. Brain transcriptome revealed only slight alterations due to antibiotic exposure. The results of these studies will help inform aquaculture practitioners and risk assessors when assessing the potential impacts of antibiotics in fish feed and the environment, with implications for host health.
Project description:The gut microbiome is a malleable microbial community that can remodel in response to various factors, including diet, and contribute to the development of several chronic diseases, including atherosclerosis. We devised an in vitro screening protocol of the mouse gut microbiome to discover molecules that can selectively modify bacterial growth. This approach was used to identify cyclic D,L-α-peptides that remodeled the Western diet (WD) gut microbiome toward the low-fat-diet microbiome state. Daily oral administration of the peptides in WD-fed LDLr-/- mice reduced plasma total cholesterol levels and atherosclerotic plaques. Depletion of the microbiome with antibiotics abrogated these effects. Peptide treatment reprogrammed the microbiome transcriptome, suppressed the production of pro-inflammatory cytokines (including interleukin-6, tumor necrosis factor-α and interleukin-1β), rebalanced levels of short-chain fatty acids and bile acids, improved gut barrier integrity and increased intestinal T regulatory cells. Directed chemical manipulation provides an additional tool for deciphering the chemical biology of the gut microbiome and might advance microbiome-targeted therapeutics.