AcuteandchronicQfeverinfectionsinhumansarecausedbyCoxiellaburnetii,whichtrafficsto and replicates in Coxiella-containing vacuoles (CCV). Infection suppresses macrophage activation in a type 4 secretion system-dependent manner, hence our central hypothesis is characterizationofT4SS-dependenteffectormoleculesinvitroandinvivowilldefine?stealthy? virulence genes. This application will identify T4SS-dependent virulence determinants that modulate macrophage signaling pathways using pathogen effector mutants and host signaling mutants that are essential for restricting replication or modulating response to infection.
Aim 1. IdentifytherangeofT4SSdependentmanipulationofmacrophage.Theworkinghypothesis ismultipleT4SSeffectorsmanipulatetheresponsetoinfectioninmacrophages.Usingaprimary bonemarrowderivedmacrophage(BMDM)cellculturethatenablesC.burnetii,RSA439(NMII) to replicate. We will extensively characterize BMDM using transcriptomic (including single cell analysis),metabolomicsandflowcytometricanalysistocomprehensivelymapT4SSdependent pathway modulation of macrophage activation.
Aim 2. Identify T4SS effectors which manipulate immune signaling. The working hypothesis is T4SS effectors target specific activation signaling pathways. To identify this broad class of T4SS effectors, tagged C. burnetii T4SS substrates will be transfected into macrophages in the context of signaling agonists. A complementary approach will use T4SS mutants to identify infection that does not modulate innateactivation.
Aim3. EstablishmechanisticbasisforT4SSeffectormodulation.Current candidatesderivedfrompreliminarydatainclude;?a)2Ankyrinrepeat-containingproteinswhich dampenagonistdrivenNF-?b?;?b)5T4SSeffectorsthatareessentialforreplicationinBMDM;?and c) 3 T4SS effectors which traffic to the nucleus (nucleomodulins). We will identify host binding partners using pull-down methods and define their role in disease using host knock-down or knock-outapproaches.EacheffectorwillbeanalyzedwitheitherTnorsite-specificmutants.

Public Health Relevance

Coxiellaburnetii,theintracellularbacterialpathogenthecausesQfever,expressavarietyofeffector proteinsviatype4secretionthatmodulatehostfunctiontoenablereplicationinmacrophage/monocytic cells.ThisapplicationwillidentifyT4SS-dependentvirulencedeterminantsthatmodulate macrophagesignalingpathwaysusingpathogeneffectormutantsandhostsignalingmutants thatareessentialforrestrictingreplicationormodulatingresponsetoinfection.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Study Section
Special Emphasis Panel (ZRG1)
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Perdue, Samuel S
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Texas A&M University
Schools of Medicine
College Station
United States
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Weber, Mary M; Faris, Robert; van Schaik, Erin J et al. (2018) Identification and characterization of arginine finger-like motifs, and endosome-lysosome basolateral sorting signals within the Coxiella burnetii type IV secreted effector protein CirA. Microbes Infect 20:302-307
Patrick, Kristin L; Wojcechowskyj, Jason A; Bell, Samantha L et al. (2018) Quantitative Yeast Genetic Interaction Profiling of Bacterial Effector Proteins Uncovers a Role for the Human Retromer in Salmonella Infection. Cell Syst 7:323-338.e6
Pandey, Aseem; Ding, Sheng Li; Qin, Qing-Ming et al. (2017) Global Reprogramming of Host Kinase Signaling in Response to Fungal Infection. Cell Host Microbe 21:637-649.e6
Weber, Mary M; Faris, Robert; van Schaik, Erin J et al. (2016) The Type IV Secretion System Effector Protein CirA Stimulates the GTPase Activity of RhoA and Is Required for Virulence in a Mouse Model of Coxiella burnetii Infection. Infect Immun 84:2524-33
Di Russo Case, Elizabeth; Samuel, James E (2016) Contrasting Lifestyles Within the Host Cell. Microbiol Spectr 4:
Weber, Mary M; Faris, Robert; McLachlan, Juanita et al. (2016) Modulation of the host transcriptome by Coxiella burnetii nuclear effector Cbu1314. Microbes Infect 18:336-45
Case, Elizabeth Di Russo; Smith, Judith A; Ficht, Thomas A et al. (2016) Space: A Final Frontier for Vacuolar Pathogens. Traffic 17:461-74
Soltysiak, Kelly A; van Schaik, Erin J; Samuel, James E (2015) Surfactant Protein D Binds to Coxiella burnetii and Results in a Decrease in Interactions with Murine Alveolar Macrophages. PLoS One 10:e0136699
van Schaik, Erin J; Chen, Chen; Mertens, Katja et al. (2013) Molecular pathogenesis of the obligate intracellular bacterium Coxiella burnetii. Nat Rev Microbiol 11:561-73
Weber, Mary M; Chen, Chen; Rowin, Kristina et al. (2013) Identification of Coxiella burnetii type IV secretion substrates required for intracellular replication and Coxiella-containing vacuole formation. J Bacteriol 195:3914-24

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