Chemoproteomic profiling of host and pathogen enzymes active in cholera.
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ABSTRACT:
SUBMITTER: Hatzios SK
PROVIDER: S-EPMC4765928 | biostudies-literature | 2016 Apr
REPOSITORIES: biostudies-literature
Publications
Chemoproteomic profiling of host and pathogen enzymes active in cholera.
Hatzios Stavroula K SK Abel Sören S Martell Julianne J Hubbard Troy T Sasabe Jumpei J Munera Diana D Clark Lars L Bachovchin Daniel A DA Qadri Firdausi F Ryan Edward T ET Davis Brigid M BM Weerapana Eranthie E Waldor Matthew K MK
Nature chemical biology 20160222 4
Activity-based protein profiling (ABPP) is a chemoproteomic tool for detecting active enzymes in complex biological systems. We used ABPP to identify secreted bacterial and host serine hydrolases that are active in animals infected with the cholera pathogen Vibrio cholerae. Four V. cholerae proteases were consistently active in infected rabbits, and one, VC0157 (renamed IvaP), was also active in human choleric stool. Inactivation of IvaP influenced the activity of other secreted V. cholerae and ...[more]
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Project description:Activity-based protein profiling (ABPP) is a chemoproteomic tool for detecting active enzymes in complex biological systems. We used ABPP to identify secreted bacterial and host serine hydrolases that are active in animals infected with the cholera pathogen Vibrio cholerae. Four V. cholerae proteases were consistently active in infected rabbits, and one, VC0157 (renamed IvaP), was also active in human cholera stool. Inactivation of IvaP influenced the activity of other secreted V. cholerae and rabbit enzymes in vivo, while genetic disruption of all four proteases increased the abundance and binding of an intestinal lectin—intelectin—to V. cholerae in infected rabbits. Intelectin also bound to other enteric bacterial pathogens, suggesting it may constitute a previously unrecognized mechanism of bacterial surveillance in the intestine that is inhibited by pathogen-secreted proteases. Our work demonstrates the power of activity-based proteomics to reveal host-pathogen enzymatic dialogue in an animal model of infection.
2016-02-22 | PXD003000 | Pride
Project description:Vibrio cholerae is the causative agent of cholera, a potentially lethal enteric bacterial infection1. Cholera toxin (CTX), a protein complex that is secreted by V. cholerae, is required for V. cholerae to cause severe disease. CTX is also thought to promote transmission of the organism, as infected individuals shed many litres of diarrhoeal fluid that typically contains in excess of 1011 organisms per litre. How the pathogen is able to reach such high concentrations in the intestine during infection remains poorly understood. Here we show that CTX increases pathogen growth and induces a distinct V. cholerae transcriptomic signature that is indicative of an iron-depleted gut niche. During infection, bacterial pathogens need to acquire iron, which is an essential nutrient for growth2. Most iron in the mammalian host is found in a chelated form within the porphyrin structure of haem, and the ability to use haem as a source of iron is genetically encoded by V. cholerae3. We show that the genes that enable V. cholerae to obtain iron via haem and vibriobactin confer a growth advantage to the pathogen only when CTX is produced. Furthermore, we found that CTX-induced congestion of capillaries in the terminal ileum correlated with an increased bioavailability of luminal haem. CTX-induced disease in the ileum also led to increased concentrations of long-chain fatty acids and L-lactate metabolites in the lumen, as well as the upregulation of V. cholerae genes that encode enzymes of the tricarboxylic acid (TCA) cycle that contain iron-sulfur clusters. Genetic analysis of V. cholerae suggested that pathogen growth was dependent on the uptake of haem and long-chain fatty acids during infection, but only in a strain capable of producing CTX in vivo. We conclude that CTX-induced disease creates an iron-depleted metabolic niche in the gut, which selectively promotes the growth of V. cholerae through the acquisition of host-derived haem and fatty acids.
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Project description:Itaconate is an immunoregulatory and anti-bacterial metabolite, and plays important roles in host-pathogen interactions. Chemoproteomic strategies have been used to explore the anti-inflammatory effects of itaconate on activated macrophages and it has been found that many key proteins in immune pathways were modified; however, how itaconate modulates pathogens was not fully understood. Here, we have designed and synthesized a series of itaconate-based bioorthogonal probes, which enable quantitative and site-specific profiling of itaconated proteins and sites in Salmonella. Among many proteins related to energy metabolism, we identified a key enzyme involved in the glyoxylate cycle, isocitrate lyase (ICL), as the most prominent target. Covalent modification of the active-site cysteine in ICL by itaconate abolishes the enzyme activity and suppresses bacterial growth. Our chemoproteomic study has uncovered the wide array of itaconation targets in Salmonella and provided a comprehensive resource for understanding the anti-bacterial function of this intriguing metabolite.
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Project description:MotivationCarbohydrate Active enzyme (CAZyme) families, encoded by human gut microflora, play a crucial role in breakdown of complex dietary carbohydrates into components that can be absorbed by our intestinal epithelium. Since nutritional wellbeing of an individual is dependent on the nutrient harvesting capability of the gut microbiome, it is important to understand how CAZyme repertoire in the gut is influenced by factors like age, geography and food habits.ResultsThis study reports a comprehensive in-silico analysis of CAZyme profiles in the gut microbiomes of 448 individuals belonging to different geographies, using similarity searches of the corresponding gut metagenomic contigs against the carbohydrate active enzymes database. The study identifies a core group of 89 CAZyme families that are present across 85% of the gut microbiomes. The study detects several geography/age-specific trends in gut CAZyme repertoires of the individuals. Notably, a group of CAZymes having a positive correlation with BMI has been identified. Further this group of BMI-associated CAZymes is observed to be specifically abundant in the Firmicutes phyla. One of the major findings from this study is identification of three distinct groups of individuals, referred to as 'CAZotypes', having similar CAZyme profiles. Distinct taxonomic drivers for these CAZotypes as well as the probable dietary basis for such trends have also been elucidated. The results of this study provide a global view of CAZyme profiles across individuals of various geographies and age-groups. These results reiterate the need of a more precise understanding of the role of carbohydrate active enzymes in human nutrition.
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