Project description:Indole is an intercellular and interkingdom signaling molecule, which is widespread in diverse ecological niches. Caenorhabditis elegans is a bacterivorous nematode living in soil and compost environments and a useful model host for the study of host-microbe interactions. While various bacteria and some plants produce a large quantity of extracellular indole, little is known about the effects of indole, its derivatives, and indole-producing bacteria on behaviors in C. elegans and animals. Here, we show that C. elegans senses and moves toward indole and indole-producing bacteria, such as Escherichia coli, Shigella boydii, Providencia stuartii, and Klebsiella oxytoca, while avoids non-indole producing pathogenic bacteria. It was also found that indole-producing bacteria and non-indole-producing bacteria exert divergent effects on egg-laying behavior of C. elegans via indole. In addition, various indole derivatives also modulate chemotaxis, egg-laying behavior, and survival of C. elegans. In contrast, indole at a high concentration to kill C. elegans that has the ability to detoxify indole via oxidation and glucosylation, indicating predator-prey interactions via a double-edged molecule indole. Transcriptional analysis showed that indole markedly up-regulated gene expression of cytochrome P450 family, UDP-glucuronosyltransferase, glutathione S-transferase, which explained well the modification of indole in C. elegans, while down-regulated expression of collagen genes and F-box genes. Our findings suggest that indole and its derivatives are important interkingdom signaling molecules in bacteria-nematode interactions.
Project description:Background: Probiotic-like bacteria treatment has been described to be associated with gut microbiota modifications. Goal: To decipher if the effects of the tested probiotic-like bacteria are due to the bacteria itself or due to the effects of the bacteria on the gut microbiota. Methodology: In this study, gut microbiota has been analyzed from feces samples of subjects with metabolic syndrome and treated with one of the 2 tested probiotic-like bacteria or with the placebo during 3months.
Project description:This SuperSeries is composed of the following subset Series: GSE25572: Depolymerization of plant cell wall glycans by symbiotic human gut bacteria (Bacteroides thetaiotaomicron) GSE25575: Depolymerization of plant cell wall glycans by symbiotic human gut bacteria (Bacteroides ovatus) Refer to individual Series
Project description:We report the application of next generation RNA sequencing to analyze the transcriptional response of Drosophila adult flies to infection by the insect pathogenic nematodes Heterorhabditis bacteriophora and their mutualistic bacteria Photorhabdus luminescens, either separately or together. We find that Heterorhabditis and Photorhabdus differentially modulate a large number of genes, many of which participate in metabolic functions, stress responses, repression of gene transcription and neuronal activities. We have also identified Drosophila genes with potential role in nematode recognition and others with putative anti-nematode properties. These findings generate novel insights into how the host immune function is shaped to respond against nematode parasites and their associated bacteria.
Project description:The gut microbiota promotes immune system development in early life, but the interactions between the gut metabolome and immune cells in the neonatal gut remains largely undefined. Here, we demonstrate that the neonatal gut is uniquely enriched with neurotransmitters, including serotonin; specific gut bacteria produce serotonin directly while downregulating monoamine oxidase A to limit serotonin breakdown. Serotonin directly signals to T cells to increase intracellular indole-3-acetaldehdye to inhibit mTOR activation and thereby promotes the differentiation of regulatory T cells, both ex vivo and in vivo in the neonatal intestine. Oral gavage of serotonin into neonatal mice leads to long-term T cell-mediated antigen-specific immune tolerance towards both dietary antigens and commensal bacteria. Together, our study has uncovered an important role for unique gut bacteria to increase serotonin availability in the neonatal gut and a novel function of gut serotonin to shape T cell response to dietary antigens and commensal bacteria to promote immune tolerance in early life.
Project description:The gut microbiota promotes immune system development in early life, but the interactions between the gut metabolome and immune cells in the neonatal gut remains largely undefined. Here, we demonstrate that the neonatal gut is uniquely enriched with neurotransmitters, including serotonin; specific gut bacteria produce serotonin directly while downregulating monoamine oxidase A to limit serotonin breakdown. Serotonin directly signals to T cells to increase intracellular indole-3-acetaldehdye to inhibit mTOR activation and thereby promotes the differentiation of regulatory T cells, both ex vivo and in vivo in the neonatal intestine. Oral gavage of serotonin into neonatal mice leads to long-term T cell-mediated antigen-specific immune tolerance towards both dietary antigens and commensal bacteria. Together, our study has uncovered an important role for unique gut bacteria to increase serotonin availability in the neonatal gut and a novel function of gut serotonin to shape T cell response to dietary antigens and commensal bacteria to promote immune tolerance in early life.
Project description:The gut microbiota promotes immune system development in early life, but the interactions between the gut metabolome and immune cells in the neonatal gut remains largely undefined. Here, we demonstrate that the neonatal gut is uniquely enriched with neurotransmitters, including serotonin; specific gut bacteria produce serotonin directly while downregulating monoamine oxidase A to limit serotonin breakdown. Serotonin directly signals to T cells to increase intracellular indole-3-acetaldehdye to inhibit mTOR activation and thereby promotes the differentiation of regulatory T cells, both ex vivo and in vivo in the neonatal intestine. Oral gavage of serotonin into neonatal mice leads to long-term T cell-mediated antigen-specific immune tolerance towards both dietary antigens and commensal bacteria. Together, our study has uncovered an important role for unique gut bacteria to increase serotonin availability in the neonatal gut and a novel function of gut serotonin to shape T cell response to dietary antigens and commensal bacteria to promote immune tolerance in early life.
Project description:Type 1 diabetes (T1D) is a chronic autoimmune disease that results from destruction of pancreatic β-cells. T1D subjects were recently shown to harbor distinct intestinal microbiome profiles. Based on these findings, the role of gut bacteria in T1D is being intensively investigated. The mechanism connecting intestinal microbial homeostasis with the development of T1D is unknown. Specific gut bacteria such as Bacteroides dorei (BD) and Ruminococcus gnavus (RG) show markedly increased abundance prior to the development of autoimmunity. One hypothesis is that these bacteria might traverse the damaged gut barrier, and their constituents elicit a response from human islets that causes metabolic abnormalities and inflammation. We have tested this hypothesis by exposing human islets to BD and RG in vitro, after which RNA-Seq analysis was performed. The bacteria altered expression of many islet genes. The commonly upregulated genes by these bacteria were cytokines, chemokines and enzymes, suggesting a significant effect of gut bacteria on islet antimicrobial and biosynthetic pathways. Additionally, each bacteria displayed a unique set of differentially expressed genes (DEGs). Ingenuity pathway analysis of DEGs revealed that top activated pathways and diseases included TREM1 Signaling and Inflammatory Response, illustrating the ability of bacteria to induce islet inflammation. The increased levels of selected factors were confirmed using immunoblotting and ELISA methods. Our data demonstrate that islets produce a complex anti-bacterial response. The response includes both symbiotic and pathogenic aspects. Both oxidative damage and leukocyte recruitment factors were prominent, which could induce beta cell damage and subsequent autoimmunity.