Insights into the genetic influences of the microbiota on the life span of a host
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ABSTRACT: To investigate the effect of mutant E. coli on Caenorhabditis elegans, we performed gene expression profiling of RNA-seq data from Caenorhabditis elegans fed with different E. coli mutants.
Project description:Escherichia coli (E. coli) mutant strains have been reported to extend the life span of Caenorhabditis elegans (C. elegans). However, the specific mechanisms through which the genes and pathways affect aging are not yet clear. In this study, we fed Drosophila melanogaster (fruit fly) various E. coli single-gene knockout strains to screen mutant strains with an extended lifespan. The results showed that D. melanogaster fed with E. coli purE had the longest mean lifespan, which was verified by C. elegans. We conducted RNA-sequencing and analysis of C. elegans fed with E. coli purE (a single-gene knockout mutant) to further explore the underlying molecular mechanism. We used differential gene expression (DGE) analysis, enrichment analysis, and gene set enrichment analysis (GSEA) to screen vital genes and modules with significant changes in overall expression. Our results suggest that E. coli mutant strains may affect the host lifespan by regulating the protein synthesis rate (cfz-2) and ATP level (catp-4). To conclude, our study could provide new insights into the genetic influences of the microbiota on the life span of a host and a basis for developing anti-aging probiotics and drugs.
Project description:To better understand how associated microorganisms ("microbiota") influence organismal aging, we focused on the model organism Drosophila melanogaster We conducted a metagenome-wide association (MGWA) as a screen to identify bacterial genes associated with variation in the D. melanogaster life span. The results of the MGWA predicted that bacterial cysteine and methionine metabolism genes influence fruit fly longevity. A mutant analysis, in which flies were inoculated with Escherichia coli strains bearing mutations in various methionine cycle genes, confirmed a role for some methionine cycle genes in extending or shortening fruit fly life span. Initially, we predicted these genes might influence longevity by mimicking or opposing methionine restriction, an established mechanism for life span extension in fruit flies. However, follow-up transcriptome sequencing (RNA-seq) and metabolomic experiments were generally inconsistent with this conclusion and instead implicated glucose and vitamin B6 metabolism in these influences. We then tested if bacteria could influence life span through methionine restriction using a different set of bacterial strains. Flies reared with a bacterial strain that ectopically expressed bacterial transsulfuration genes and lowered the methionine content of the fly diet also extended female D. melanogaster life span. Taken together, the microbial influences shown here overlap with established host genetic mechanisms for aging and therefore suggest overlapping roles for host and microbial metabolism genes in organismal aging.IMPORTANCE Associated microorganisms ("microbiota") are intimately connected to the behavior and physiology of their animal hosts, and defining the mechanisms of these interactions is an urgent imperative. This study focuses on how microorganisms influence the life span of a model host, the fruit fly Drosophila melanogaster First, we performed a screen that suggested a strong influence of bacterial methionine metabolism on host life span. Follow-up analyses of gene expression and metabolite abundance identified stronger roles for vitamin B6 and glucose than methionine metabolism among the tested mutants, possibly suggesting a more limited role for bacterial methionine metabolism genes in host life span effects. In a parallel set of experiments, we created a distinct bacterial strain that expressed life span-extending methionine metabolism genes and showed that this strain can extend fly life span. Therefore, this work identifies specific bacterial genes that influence host life span, including in ways that are consistent with the expectations of methionine restriction.
Project description:Comparison of gene expression profiles of Caenorhabditis elegans fed a complex microbiota (either a synthetic community or in soil) or a standard Escherichia coli diet. We find that immune and digestion genes are up-regulated in C. elegans that were fed a complex microbiota.
Project description:Transcriptome profiling of three models with impaired insulin/IGF1 signaling. 1. Deep sequencing of endogenous mRNA from Caenorhabditis elegans N2 var. Bristol (wildtype) and daf-2(e1370) mutant; 2. Deep sequencing of endogenous mRNA from murine embryonic fibroblasts (MEF) wildtype and irs1-/- knockout; 3. Deep sequencing of endogenous mRNA from murine embryoinic fibroblast (MEF) insr+/- -lox and insr+/- knockout 14 samples examined: C. elegans N2 var. Bristol (wildtype) vs. daf-2(e1370) mutant; MEF wildtype vs. irs1-/- knockout; MEF insr+/- -lox vs. insr +/- knockout
Project description:Transcriptional profiling of Caenorhabditis elegans comparing control E. coli OP50-fed C. elegans with L. sphaericus-fed C. elegans
Project description:Transcriptome profiling of three models with impaired insulin/IGF1 signaling. 1. Deep sequencing of endogenous mRNA from Caenorhabditis elegans N2 var. Bristol (wildtype) and daf-2(e1370) mutant; 2. Deep sequencing of endogenous mRNA from murine embryonic fibroblasts (MEF) wildtype and irs1-/- knockout; 3. Deep sequencing of endogenous mRNA from murine embryoinic fibroblast (MEF) insr+/- -lox and insr+/- knockout Jena Centre for Systems Biology of Ageing - JenAge (www.jenage.de)
Project description:Transcriptional profiling of Caenorhabditis elegans comparing control E. coli OP50-fed C. elegans with L. sphaericus-fed C. elegans Two-condition experiment, E. coli OP50-fed C. elegans vs. L. sphaericus-fed C. elegans
Project description:We utilized a Caenorhabditis elegans (C. elegans) model of human tauopathy to investigate the role of DNA glycosylases (Ung-1 and Nth-1 knockout worms) in disease development and progression. We then performed gene expression profiling analysis using data obtained from RNA-seq of 12 different genotypes grown under normal conditions.
Project description:One of the most important issues in the study of aging is to discover compounds with longevity-promoting activity and to unravel their underlying mechanisms. Queen honey bees are continuously fed royal jelly (RJ), and they live more than 10 times longer than hive workers, derived from the same diploid genome, which are fed it only for a short period of time during their larval stages. Therefore, RJ is likely to contain longevity-promoting agents for queens. RJ has been reported to possess diverse pharmacological properties. Furthermore, protease-treated RJ (pRJ) has additional beneficial activities. How RJ and pRJ exert these effects and which components in them play a critical role is largely unknown. The evolutionally conserved mechanisms that control lifespan have been indicated. The nematode Caenorhabditis elegans has been widely used for study of aging and longevity, due to its relatively short lifespan and well-established genetic pathways. The purpose of the present study was to elucidate whether RJ and its related substances contain the life span-extending activity in C. elegans and to obtain some insight into the active agents and their mechanisms. We found that both RJ and pRJ extended the lifespan of C. elegans. The life span-extending activity of pRJ was enriched by ODS column chromatography (pRJ-Fraction 5). pRJ-Fr. 5 extended the life span partly by acting through the FOXO transcription factor DAF-16, the activation of which is known to promote longevity in C. elegans by reducing insulin/IGF-1 signaling (IIS). pRJ-Fr. 5 induced changes in the expression of 3 genes encoding insulin-like peptides. Moreover, pRJ-Fr. 5 and reduced IIS shared some common features in terms of their effect on gene expression, such as up-regulation of dod-3 and down-regulation of dod-19, dao-4 and fkb-4. The dod-19 is a previously identified life span determinant in C. elegans, and the fkb-4 encodes a homologue of the mammalian FK506-binding protein. 10-Hydroxy-2-decenoic acid (10-HDA), which was present in high concentration in pRJ-Fr. 5, increased the lifespan independently of DAF-16 activity.These results demonstrate that RJ and its related substances extended the life span in C. elegans, suggesting that RJ may contain longevity-promoting factors common to diverse species across phyla. pRJ-Fr. 5 had higher life span-extending activity than either RJ or pRJ and extended the life span in part through the IIS-DAF-16 pathway. We provide the first evidence that 10-HDA, a defined natural product in RJ, extended organismal lifespan. It is noteworthy that 10-HDA performed its lifespan-extending function through a mechanism totally different from the IIS-DAF-16 pathway. Further search and characterization of the lifespan-extending agents in RJ and pRJ may broaden our understanding of the gene network of longevity regulation in diverse species and provide the possibility for nutraceutical interventions in the aging process. C. elegans N2 hermaphrodites were untreated or treated with pRJ-Fr. 5 (25mg/ml) for 24 h starting at the larval 4 (L4) stage.