This proposal is Project 1 within a P01 renewal, entitled "Intracellular pathogens and innate immunity." Listeria monocytogenes is a highly amenable model intracellular pathogen that induces robust and long-lived cell mediated immunity. The goal of the previous proposal was to identify L. monocytogenes determinants that activate a host cytosolic surveillance pathway (CSP) of innate immunity that leads to the expression of IFNB and co-regulated genes. We hypothesize that this pathway contributes significantly to the potent and long-lived cell-mediated immunity induced by L. monocytogenes. Using a genetic screen and subsequent biochemistry, we identified c-di-AMP as the listerial ligand that is secreted through a multidrug efflux pump and activates the CSP. Thus, c-di-AMP is a newly discovered PAMP. C-di-AMP is also a novel and conserved small bacterial signaling molecule that appears essential for bacterial growth. We have identified the di-adenylate cyclase (DacA) and c-di-AMP phosphodiesterase (Pde).
In Aim 1, we propose to further characterize the molecular determinants that lead to expression of c-di-AMP and generate a panel of well-characterized strains that express either enhanced or diminished levels of c-di-AMP. We will also address the following questions: What are the bacterial components that regulate c-di-AMP production? Does c-di- AMP act from the inside and/or the outside of bacteria? What is the physiologic role of c-di-AMP? In Aim 2, we will use the strains constructed above to determine the role of c-di-AMP during infection of macrophages and dendritic cells in vitro. We will also evaluate the effects of purified c-di-AMP on dendritic cell activation. In collaboration with the Vance Lab (Project 3), we will use ENU mutagenesis to identify novel host factors that control the CSP. In preliminary data, we identified Sting (Stimulator of interferon genes) as a critical host component necessary for response to L. monocytogenes, M. tuberculosis, and c-di-AMP. In the final Aim, we will test the hypothesis that c-di-AMP production is essential for the full expression of L. monocytogenes pathogenesis, and importantly, contributes to the induction of cell-mediated immunity. We will examine the role of c-di-AMP as an adjuvant.
We recently discovered that the intracellular bacterial pathogen, Listeria monocytogenes, secretes a novel small di-cyclic molecule that is essential for bacterial growth and stimulates a robust host response leading to the production of interferon. These studies may impact the development of vaccines and therapeutics that protect against infectious disease agents.
|Kranzusch, Philip J; Lee, Amy S Y; Wilson, Stephen C et al. (2014) Structure-guided reprogramming of human cGAS dinucleotide linkage specificity. Cell 158:1011-21|
|Burke, Thomas P; Loukitcheva, Anastasia; Zemansky, Jason et al. (2014) Listeria monocytogenes is resistant to lysozyme through the regulation, not the acquisition, of cell wall-modifying enzymes. J Bacteriol 196:3756-67|
|Bécavin, Christophe; Bouchier, Christiane; Lechat, Pierre et al. (2014) Comparison of widely used Listeria monocytogenes strains EGD, 10403S, and EGD-e highlights genomic variations underlying differences in pathogenicity. MBio 5:e00969-14|
|Tenthorey, Jeannette L; Kofoed, Eric M; Daugherty, Matthew D et al. (2014) Molecular basis for specific recognition of bacterial ligands by NAIP/NLRC4 inflammasomes. Mol Cell 54:17-29|
|Lee, Bettina L; Barton, Gregory M (2014) Trafficking of endosomal Toll-like receptors. Trends Cell Biol 24:360-9|
|Sivick, Kelsey E; Arpaia, Nicholas; Reiner, Gabrielle L et al. (2014) Toll-like receptor-deficient mice reveal how innate immune signaling influences Salmonella virulence strategies. Cell Host Microbe 15:203-13|
|Archer, Kristina A; Durack, Juliana; Portnoy, Daniel A (2014) STING-dependent type I IFN production inhibits cell-mediated immunity to Listeria monocytogenes. PLoS Pathog 10:e1003861|
|Arpaia, Nicholas; Barton, Gregory M (2013) The impact of Toll-like receptors on bacterial virulence strategies. Curr Opin Microbiol 16:17-22|
|Isaac, Dervla T; Coady, Alison; Van Prooyen, Nancy et al. (2013) The 3-hydroxy-methylglutaryl coenzyme A lyase HCL1 is required for macrophage colonization by human fungal pathogen Histoplasma capsulatum. Infect Immun 81:411-20|
|Aachoui, Youssef; Leaf, Irina A; Hagar, Jon A et al. (2013) Caspase-11 protects against bacteria that escape the vacuole. Science 339:975-8|
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