title: The DNA sensor, cyclic GMP-AMP synthase, is essential for induction of IFN-β during Chlamydia trachomatis infection.
abstract: IFN-β has been implicated as an effector of oviduct pathology resulting from genital chlamydial infection in the mouse model. In this study, we investigated the role of cytosolic DNA and engagement of DNA sensors in IFN-β expression during chlamydial infection. We determined that three-prime repair exonuclease-1, a host 3' to 5' exonuclease, reduced IFN-β expression significantly during chlamydial infection using small interfering RNA and gene knockout fibroblasts, implicating cytosolic DNA as a ligand for this response. The DNA sensor cyclic GMP-AMP synthase (cGAS) has been shown to bind cytosolic DNA to generate cyclic GMP-AMP, which binds to the signaling adaptor stimulator of IFN genes (STING) to induce IFN-β expression. We determined that cGAS is required for IFN-β expression during chlamydial infection in multiple cell types. Interestingly, although infected cells deficient for STING or cGAS alone failed to induce IFN-β, coculture of cells depleted for either STING or cGAS rescued IFN-β expression. These data demonstrate that cyclic GMP-AMP produced in infected cGAS(+)STING(-) cells can migrate into adjacent cells via gap junctions to function in trans in cGAS(-)STING(+) cells. Furthermore, we observed cGAS localized in punctate regions on the cytosolic side of the chlamydial inclusion membrane in association with STING, indicating that chlamydial DNA is most likely recognized outside the inclusion as infection progresses. These novel findings provide evidence that cGAS-mediated DNA sensing directs IFN-β expression during Chlamydia trachomatis infection and suggest that effectors from infected cells can directly upregulate IFN-β expression in adjacent uninfected cells during in vivo infection, contributing to pathogenesis.
authors: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
authors: Yugen
authors: Y
authors: Zhang
authors: Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202;
authors: Laxmi
authors: L
authors: Yeruva
authors: Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261;
authors: Anthony
authors: A
authors: Marinov
authors: Department of Microbiology and Immunology, University of Maryland, Baltimore, MD 21201; and.
authors: Daniel
authors: D
authors: Prantner
authors: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
authors: Priscilla B
authors: PB
authors: Wyrick
authors: Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205.
authors: Vladimir
authors: V
authors: Lupashin
authors: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; nagaraja@email.unc.edu.
authors: Uma M
authors: UM
authors: Nagarajan
mesh_terms: D000818:Animals; D002690:Chlamydia Infections / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D002692:Chlamydia trachomatis / Q000235:genetics / Q000276:immunology*; D003600:Cytosol / Q000276:immunology; D004269:DNA, Bacterial / Q000235:genetics / Q000276:immunology*; D017629:Gap Junctions / Q000235:genetics / Q000276:immunology; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D016899:Interferon-beta / Q000235:genetics / Q000276:immunology*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D051379:Mice; D009712:Nucleotides, Cyclic / Q000235:genetics / Q000276:immunology; D009713:Nucleotidyltransferases / Q000235:genetics / Q000276:immunology*; D000099197:STING Protein; D000099235:Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase
chemical_list: D004269:DNA, Bacterial; D016899:Interferon-beta; D008565:Membrane Proteins; D009712:Nucleotides, Cyclic; D009713:Nucleotidyltransferases; C532857:STING1 protein, human; D000099197:STING Protein; C584311:cyclic guanosine monophosphate-adenosine monophosphate; C578390:cGAS protein, human; D000099235:Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase