Antiviral Response Independent of IFN Regulatory Factor 3, IFN-Β Promoter Stimulator 1, and IFN This Information Is Current As of September 27, 2021
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Long Double-Stranded RNA Induces an Antiviral Response Independent of IFN Regulatory Factor 3, IFN-β Promoter Stimulator 1, and IFN This information is current as of September 27, 2021. Stephanie J. DeWitte-Orr, Devangi R. Mehta, Susan E. Collins, Mehul S. Suthar, Michael Gale, Jr. and Karen L. Mossman J Immunol 2009; 183:6545-6553; Prepublished online 28 October 2009; Downloaded from doi: 10.4049/jimmunol.0900867 http://www.jimmunol.org/content/183/10/6545 http://www.jimmunol.org/ Supplementary http://www.jimmunol.org/content/suppl/2009/10/28/jimmunol.090086 Material 7.DC1 References This article cites 39 articles, 20 of which you can access for free at: http://www.jimmunol.org/content/183/10/6545.full#ref-list-1 Why The JI? Submit online. by guest on September 27, 2021 • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2009 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Long Double-Stranded RNA Induces an Antiviral Response Independent of IFN Regulatory Factor 3, IFN- Promoter Stimulator 1, and IFN1 Stephanie J. DeWitte-Orr,* Devangi R. Mehta,* Susan E. Collins,* Mehul S. Suthar,† Michael Gale, Jr.,† and Karen L. Mossman2* Virus infection elicits a robust innate antiviral response dominated by the production of type 1 IFN. In nonprofessional innate immune cells such as fibroblasts, type 1 IFN is rapidly produced following the recognition of viral dsRNA and the subsequent activation of the constitutively expressed transcription factor IFN regulatory factor 3 (IRF3). Although origin, localization, and length are factors in mediating dsRNA recognition and binding by cellular dsRNA-binding proteins, the biological significance of differential dsRNA binding is unclear, since the subsequent signaling pathways converge on IRF3. In this study, we show a dsRNA Downloaded from length-dependent activation of IRFs, IFNs, and IFN-stimulated genes in mouse fibroblasts. The length dependence was exacer- bated in fibroblasts deficient in the mitochondria-associated adaptor IFN- promoter stimulator 1 and IRF3, suggesting that antiviral gene induction mediated by short and long dsRNA molecules is predominantly IFN- promoter stimulator 1 and IRF3 dependent and independent, respectively. Furthermore, we provide evidence of an innate antiviral response in fibroblasts in the absence of both IRF3 and type 1 IFN induction. Even with these key modulators missing, a 60–90% inhibition of virus replication was observed following 24-h treatment with short or long dsRNA molecules, respectively. These data provide evidence of a novel http://www.jimmunol.org/ antiviral pathway that is dependent on dsRNA length, but independent of the type 1 IFN system. The Journal of Immunology, 2009, 183: 6545–6553. iral infection of susceptible cells leads to the induction melanoma differentiation-associated gene 5 (MDA-5) bind dsRNA of a cellular antiviral response aimed at limiting virus and mediate antiviral signaling through the adaptors Toll/IL-1R V replication and spread. dsRNA, a byproduct in the rep- domain-containing adaptor inducing IFN- (TRIF) and IFN- pro- lication cycle of virtually all viruses (1), is a potent inducer of moter stimulator 1(IPS-1), respectively (2). Both adaptors subse- innate and adaptive immune responses. Three different families of quently activate the cellular transcription factors NF-B and IFN by guest on September 27, 2021 pattern recognition receptors, the TLRs, the retinoic acid-inducible regulatory factor (IRF) 3, leading to IFN- and cytokine produc- 3 gene I (RIG-I) -like receptors (RLRs) and the nucleotide oli- tion. Similar to the cytoplasmic RLRs, protein kinase regulated by gomerization domain-like receptors (NLRs) bind dsRNA and ini- RNA (PKR) also binds dsRNA and activates IRF3 through IPS-1 tiate cellular signaling pathways (2). The TLRs and RLRs elicit (3). IFN- signaling through the JAK-STAT pathway, which in-  type 1 IFN and cytokine production while NLRs promote IL-1 cludes IRF9 as an essential component, leads to the induction of maturation through caspase 1 activation. In nonprofessional innate IRF7 and amplification of the cellular antiviral response through immune cells such as fibroblasts, TLR3 and the RLRs RIG-I and the induction of IFN-␣ species and IFN-stimulated genes (ISGs) (4). *Department of Pathology & Molecular Medicine, Michael DeGroote Institute for Recent studies have begun to characterize the dsRNA-binding Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada; properties of TLR3, PKR, MDA-5, and RIG-I. Binding of dsRNA and †Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98195 to TLR3 depends strongly on pH and dsRNA length, suggesting that TLR3 signaling initiates within an endosome through a pH- Received for publication March 18, 2009. Accepted for publication September 8, 2009. dependent binding mechanism and that sufficient dsRNA length The costs of publication of this article were defrayed in part by the payment of page (ϳ45 bp) is required to bind to both the N-terminal and C-terminal charges. This article must therefore be hereby marked advertisement in accordance regions of the TLR3 ectodomain (5–8). A similar minimal length with 18 U.S.C. Section 1734 solely to indicate this fact. dependence was observed for dsRNA to bind two PKR monomers 1 This study was funded by the National Institutes of Health and the Canadian Insti- tute for Health Research (MOP-57669). and elicit PKR autophosphorylation and activation (9, 10). With the cytosolic RLRs RIG-I and MDA-5, both dsRNA origin and 2 Address correspondence and reprint requests to Dr. Karen L. Mossman, Department of Pathology & Molecular Medicine, McMaster University, 1200 Main Street West, length influence recognition and binding. RIG-I preferentially rec- MDCL 5026, Hamilton, Ontario, Canada, L8N 3Z5. E-mail address: mossk@ ognizes RNA from a variety of RNA viruses while MDA-5 binds mcmaster.ca the dsRNA mimic polyinosinic:polycytidylic acid (poly (I:C)) and 3 Abbreviations used in this paper: RIG-I, retinoic acid-inducible gene I; IPS-1, IFN- promoter stimulator 1; IRF, IFN regulatory factor; ISG, IFN-stimulated gene; picornavirus RNA (11). Furthermore, RIG-I and MDA-5 were MDA-5, melanoma differentiation-associated gene 5; MEF, mouse embryo fibroblast; shown to preferentially bind to short and long dsRNA molecules, NLR, nucleotide oligomerization domain-like receptor; poly(I:C), polyinosinic:poly- respectively (12). Regardless of which cellular protein senses the cytidylic acid; PKR, protein kinase regulated by RNA; TRIF, Toll/IL-1 receptor do- main-containing adaptor inducing IFN-; VSV, vesicular stomatitis virus; VSVgfp, dsRNA, current models suggest that activation of all sensors leads VSV expressing GFP; HSV-1gfp, HSV-1 expressing GFP; WNv, West Nile virus; to IRF3 activation and subsequent ISG and type 1 IFN induction. WT, wild type; MOI, multiplicity of infection; C , threshold cycle. t The importance of IRF3 in the early and late phases of type 1 Copyright © 2009 by The American Association of Immunologists, Inc. 0022-1767/09/$2.00 IFN expression and antiviral immunity was demonstrated through www.jimmunol.org/cgi/doi/10.4049/jimmunol.0900867 6546 dsRNA LENGTH-DEPENDENT, IFN-INDEPENDENT ANTIVIRAL RESPONSE Table I. Details of in vitro transcribed dsRNA generation from the cloned WNv genomea dsRNA Source Gene Length (bp) Primersb v200 WNv E 200 Sense: TCCTCCAACTGCGAGAAACGTG Antisense: AAAGGAGCGCAGAGACTAGCCG v500 WNv E 500 Sense: TCCTCCAACTGCGAGAAACGTG Antisense: TGGCACGGATGGACCTTG v1000 WNv E 1000 Sense: TCCTCCAACTGCGAGAAACGTG Antisense: ACACATGCGCCAAATTTGCC v3000 NS3-NS4B 3000 Sense: CATGACAACCAACCCCCACGCATGATG Antisense: GCGGGCGTGATGGTTGAAGGTGT a Primer sequences used for amplifying PCR product templates for dsRNA in vitro transcription. b All primers included a T7 sequence tag (5Ј-taatacgactcactataggg-3Ј) used by the T7 polymerase during dsRNA synthesis. the generation of IRF3Ϫ/Ϫ and IRF3Ϫ/Ϫ9Ϫ/Ϫ mice (4). Mice de- viral dsRNA is length dependent in WT mouse fibroblasts and that ficient for IRF3 were more vulnerable to viral infection and IFN the length dependence is exacerbated in the absence of IRF3. Fur- production was reduced 20- to 50-fold. In the absence of both IRF3 thermore, we provide evidence of an IRF3- and type 1 IFN- inde- and IRF9, type 1 IFN production was completely ablated (4). Since pendent antiviral response that is more robustly activated by longer IRF7 gene expression is dependent on type 1 IFN signaling, levels dsRNA molecules. Downloaded from of this transcription factor were significantly diminished in cells lacking IRF3 and absent in cells lacking IRF3 and IRF9 following Materials and Methods viral infection. These studies led to a model in which constitutive Cells and viruses expression of low levels of type 1 IFN in uninfected cells supports Ϫ Ϫ Ϫ Ϫ basal expression of equally low levels of IRF7. Upon viral infec- MEFs were derived from WT C57BL/6, IRF3 / (4), IRF3 / and IRF9Ϫ/Ϫ (4), IPS-1Ϫ/Ϫ and IPS-1ϩ/ϩ littermate control mice and were tion, activation of IRF3 initiates a positive feedback loop resulting http://www.jimmunol.org/ maintained in ␣-MEM supplemented with 10% FBS, 100 U ⅐ mlϪ1 peni-  ␣ Ϫ1 in robust IFN- , IRF7, IFN- , and ISG induction (13). Subsequent cillin, 100 g ⅐ ml streptomycin, and 2 mM L-glutamine. Experiments Ϫ/Ϫ Ϫ/Ϫ Ϫ/Ϫ studies in IRF7 and IRF3 7 mice confirmed the require- were performed with cells at passages three to eight.