Sensing adenovirus infection: activation of interferon regulatory factor 3 in RAW 264.7 cells.

TitleSensing adenovirus infection: activation of interferon regulatory factor 3 in RAW 264.7 cells.
Publication TypeJournal Article
Year of Publication2012
AuthorsStein SC, Falck-Pedersen E
JournalJ Virol
Date Published2012 Apr
KeywordsAdenoviridae, Adenoviruses, Human, Animals, Cell Line, DEAD-box RNA Helicases, DNA Helicases, DNA-Binding Proteins, Enzyme Inhibitors, Gene Silencing, Genome, Viral, Glycoproteins, Humans, Interferon Regulatory Factor-3, Macrophages, Membrane Proteins, Mice, Models, Biological, Nuclear Proteins, Phosphoproteins, Phosphorylation, Protein-Serine-Threonine Kinases, RNA Polymerase III, RNA, Small Interfering, RNA-Binding Proteins, Signal Transduction, Transcription, Genetic

We have used the RAW 264.7 murine macrophage-like cell line as a platform to characterize the recognition and early signaling response to recombinant adenoviral vectors (rAdV). Infection of RAW 264.7 cells triggers an early response (2 to 6 h postinfection) that includes phosphorylation of the interferon (IFN) response factor 3 (IRF3) transcription factor, upregulation of IRF3 primary response genes (interferon-stimulated gene 56 [ISG56], beta IFN [IFN-β]), and subsequent type I IFN secondary signaling (STAT1/2 phosphorylation). Using short hairpin RNA (shRNA) lentiviral vectors, we show an essential role for Tank binding kinase 1 (TBK1) in this pathway. Data also support a role for STING (MITA) as an adaptor functioning in response to rAdV infection. Using UV/psoralen (Ps)-inactivated virus to block viral transcription, Ps-inactivated virus stimulated primary (IRF3) and secondary (STAT1/2) activation events to the same degree as untreated virus. IRF3 phosphorylation was not blocked in RAW 264.7 cells pretreated with the RNA polymerase III inhibitor ML60218. However, they were compromised in the type I IFN-dependent secondary response (phosphorylation of STAT1/STAT2). At 24 h postinfection, ML60218-treated cells were compromised in the overall antiviral response. Therefore, initial sensing of rAdV or viral DNA (vDNA) does not depend on viral template transcription, but ML60218 treatment influences cellular cascades required for an antiviral response to rAdV. Using overexpression or knockdown assays, we examined how four DNA sensors influence the antiviral response. Knockdown of DNA Activator of Interferon (DAI) and p204, the murine ortholog to IFI16, had minimal influence on IRF3 phosphorylation. However, knockdown of absent in melanoma 2 (AIM2) and the helicase DDX41 resulted in diminished levels of (pser388)IRF3 following rAdV infection. Based on these data, multiple DNA sensors contribute to an antiviral DNA recognition response, leading to TBK1-dependent IRF3 phosphorylation in RAW 264.7 cells.

Alternate JournalJ Virol
PubMed ID22345436
PubMed Central IDPMC3318612
Grant ListR01 AI094050 / AI / NIAID NIH HHS / United States
R56 AI063142 / AI / NIAID NIH HHS / United States

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