Project description:The interplay between pathogens and hosts has been studied for decades using targeted approaches such as the analysis of mutants and host immunological responses. Although much has been learned from such studies, they focus on individual pathways and fail to reveal the global effects of infection on the host. To alleviate this issue, high-throughput methods such as transcriptomics and proteomics have been used to study host-pathogen interactions. Recently, metabolomics was established as a new method to study changes in the biochemical composition of host tissues. We report a metabolomics study of Salmonella enterica serovar Typhimurium infection. We used Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Direct Infusion to reveal that dozens of host metabolic pathways are affected by Salmonella in a murine infection model. In particular, multiple host hormone pathways are disrupted. Our results identify unappreciated effects of infection on host metabolism and shed light on mechanisms used by Salmonella to cause disease, and by the host to counter infection. Female C57BL/6 mice were infected with Salmonella enterica serovar Typhimurium SL1344 cells by oral gavage. Feces and livers were collected and metabolites extracted using acetonitrile. For experiments with feces, samples were collected from 4 mice before and after infection. For liver experiments, 11 uninfected and 11 infected mice were used. Samples were combined into 3 groups of 3-4 mice each, resulting in the analysis of 3 group samples of uninfected and 3 of infected mice. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140 [PMID 19081807]). To identify differences in metabolite composition between uninfected and infected samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from uninfected and infected mice. To assign possible metabolite identities, monoisotopic neutral masses of interest were queried against MassTrix (http://masstrix.org). Masses were searched against the Mus musculus database within a mass error of 3 ppm. Data were analyzed by unpaired t tests with 95% confidence intervals.

Project description:Background: Arachidonic acid (AA) metabolism pathway is dominant in metabolic programming after hypoxia exposure, but its biological function is disputed and require in-depth studies. In this research, we aimed at integrating plasma metabolomics and transcriptomics approaches to systematically explore its roles in response to acute hypoxia based on model of acute high-altitude exposure. Methods: Blood samples were taken from 53 enrolled subjects before and after their exposure to high altitude. Ultra-performance liquid chromatography- quadrupole time-of-flight mass spectrometry and RNA sequencing were performed to acquire corresponding metabolomic and transcriptomic profiling along with hypoxia exposure, separately. Influential modules comprising essential metabolites and genes were identified by weighted gene co-expression network analysis (WGCNA) after integrating metabolic information with phenotypic and transcriptomic datasets, respectively. Results: Enrolled individuals showed significant alterations in heart rate, SpO2, hemoglobin and Lake Louise Score (LLS) in response to hypoxia. Metabolomics profiling demonstrated that AA metabolism pathway was remarkable in these metabolic alterations. Integrated analysis of metabolomic and transcriptomic data revealed that increasing AA metabolism pathway might count for gas transport incapacitation and disorders in hemoglobin metabolism under hypoxia stimuli. Moreover, identified in further analysis and another cohort, excessively elevated AA metabolism pathway was involved in poor response to hypoxia. Conclusion: Our study, for the first time, constructed the maps of AA metabolism pathway in response to hypoxia; and revealed the crosstalk between phenotypic variation to hypoxia and AA metabolism pathway. These findings will not only advanced pathophysiological mechanisms for acute hypoxic diseases, but provided new insights into critical roles of AA metabolism pathway in development and prevention of these diseases.

Project description:To cause disease, Salmonella enterica serovar Typhimurium requires two type-III secretion systems, encoded on Salmonella Pathogenicity Islands 1 and 2 (SPI-1 and -2). These secretion systems serve to deliver virulence proteins, termed effectors, into the host cell cytosol. While the importance of these effector proteins to promote colonization and replication within the host has been established, the specific roles of individual secreted effectors in the disease process are not well understood. In this study, we used an in vivo gallbladder epithelial cell infection model to study the function of the SPI-2-encoded effector, SseL. Deletion of the sseL gene resulted in bacterial filamentation and elongation and unusual localization of Salmonella within infected epithelial cells. Infection with the ?sseL strain also caused dramatic changes in lipid metabolism and led to massive accumulation of lipid droplets in infected cells. Some of these changes were investigated through metabolomics of gallbladder tissue. This phenotype was directly attributed to the deubiquitinase activity of SseL, as a Salmonella strain carrying a single point mutation in the catalytic cysteine resulted in the same phenotype as the deletion mutant. Excessive buildup of lipids due to the absence of a functional sseL gene was also observed in S. Typhimurium-infected livers. These results demonstrate that SseL alters host lipid metabolism in infected epithelial cells by modifying ubiquitination patterns of cellular targets. Female C57BL/6 mice were infected with the indicated strain of Salmonella enterica serovar Typhimurium by oral gavage. Four gallbladders were collected and pooled per sample group and metabolites extracted using a mixture of methanol and chloroform. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140). To identify differences in metabolite composition between different groups of samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from each group of mice. To assign possible metabolite identities, monoisotopic neutral masses of interest were queried against MassTrix (http://masstrix.org). Masses were searched against the Mus musculus database within a mass error of 3 ppm.

Project description:<div>BACKGROUND: Epidemiological evidence suggests a link between pesticide exposure and the development of metabolic diseases. However, most experimental studies have evaluated the metabolic effects of pesticides using individual molecules, often at non relevant doses or in combination with other risk factors such as high fat diets.<br></div><div>OBJECTIVES: We aimed to evaluate, in mice, the metabolic consequences of chronic dietary exposure to a pesticide mixture at non-toxic doses, relevant to consumers’ risk assessment.<br></div> METHODS: A mixture of six pesticides commonly used in France i.e. boscalid, captan, chlorpyrifos, thiofanate, thiacloprid, and ziram was incorporated in a standard chow diet, at doses exposing mice to the acceptable daily intake (ADI) of each pesticide. Wild-type (WT) and Constitutive Androstane Receptor knock-out (CAR-/-) C57Bl6/J male and female mice were exposed for 52 weeks. We assessed metabolic parameters (body-weight, food and water consumption, glucose tolerance, urinary metabolome) throughout the experiment. At the end of the experiment, we evaluated liver metabolism (histology, transcriptomics, metabolomics) and pesticide detoxification using LC/MS.<br>RESULTS: In males, pesticide exposure increased body weight and adiposity and induced hepatic steatosis and glucose intolerance. Exposed females exhibited fasted hyperglycaemia, hepatic oxidative stress and perturbations of gut microbiota-related urinary metabolites. The Constitutive Androstane Receptor is involved in the sexually dimorphic response to pesticide exposure.<br><div> CONCLUSIONS: We show for the first time the sexually dimorphic obesogen and diabetogen effects of a chronic dietary exposure to a realistic mixture of pesticides, which are partially mediated through CAR. This raises questions about the relevance of ADI for individual pesticides when present in a mixture.</div><div><br></div><div><b>Untargeted urine UPLC-MS assay</b> protocols and data are reported in the current study <b>MTBLS596</b>.</div><div><br><b>Untargeted urine, plasma and liver NMR assay</b> protocols and data associated to this study are reported in <a href=https://www.ebi.ac.uk/metabolights/mtbls602><b>MTBLS602</b></a>.<br></div>

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Metabolomics analysis for gut bacteria after pesticide exposure

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