Regulation of STAT signaling in mouse bone marrow derived dendritic cells by respiratory syncytial virus.
OBJECTIVE
Dendritic cells (DCs) act as a portal for virus invasion as well as potent antigen-presenting cells (APCs) involved in the antiviral host response. Interferons (IFNs) are produced in response to bacterial and viral infection and activate innate immune responses to efficiently counteract and remove pathogenic invaders. Respiratory syncytial virus (RSV) could inhibit IFN-mediated signaling pathway in epithelial cells; however, the effects of RSV on IFN signaling in the dendritic cells (DCs) are still unknown.


METHODS
Mouse bone marrow derived DCs (BMDCs) were mock or infected with RSV at different multiplicity of infection (MOI) for 24h, and then treated with different cytokines such as interferon-β (IFN-β), IFN-γ or interleukin-10 (IL-10). The mRNA expression of RSV nonstructural protein-1 (NS-1) and NS-2 was detected by RT-PCR. The expression of Janus family kinase-signal transducer and activator of transcription (JAK/STAT) signaling proteins was assessed by immunoblotting assays. The nuclear localization of specific signaling proteins was determined by immunofluorescence assay.


RESULTS
Increasing amounts of NS-1 or NS-2 mRNA expression in BMDCs were observed with infected RSV at increasing MOI, suggesting BMDCs were permissive for viral gene expression. Further examination of the IFN-β signaling cascade showed RSV infection increased the total cellular levels of STAT1 and STAT2 in BMDCs, but impaired the IFN-β-dependent phosphorylation and nuclear localization of STAT1 and STAT2. The inhibitory effects of RSV on STAT1 and STAT2 phosphorylation and translocation were abolished by UV inactivation. In contrast, RSV did not inhibit the IFN-γ-stimulated STAT1 phosphorylation and nuclear localization. IL-10-stimulated STAT3 phosphorylation was also unaffected by RSV.


CONCLUSIONS
As well as RSV inhibiting STAT protein levels through degradation mechanisms in epithelial cells, these findings demonstrate that RSV also can specifically inhibit the type I interferon response in BMDCs through regulation of STAT1 and STAT2 phosphorylation and nuclear translocation.
Infectious Diseases Program, Lovelace Respiratory Research Institute, Albuquerque, NM 87108, USA. jiezjlxh@gmail.com
Zhijun
Z
Jie
Darrell L
DL
Dinwiddie
Albert P
AP
Senft
Kevin S
KS
Harrod
D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism* / Q000821:virology; D007372:Interferons / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D012136:Respiratory Syncytial Viruses / Q000276:immunology*; D050791:STAT Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction; D014779:Virus Replication / Q000235:genetics
D050791:STAT Transcription Factors; D016753:Interleukin-10; D007372:Interferons
J Virol. 2008 Sep;82(17):8780-96
18562519
J Virol. 2005 Jul;79(14):9315-9
15994826
J Virol. 1999 Dec;73(12):9928-33
10559305
Am J Respir Cell Mol Biol. 2008 Jun;38(6):661-70
18218993
Cell Microbiol. 2006 Jun;8(6):907-22
16681834
J Virol. 2003 Jul;77(13):7635-44
12805463
J Virol. 2007 Apr;81(7):3428-36
17251292
EMBO J. 1997 Oct 1;16(19):5894-903
9312047
J Virol. 2002 Nov;76(22):11476-83
12388709
Trends Microbiol. 2004 Jul;12(7):337-45
15223061
J Immunol. 2002 Sep 1;169(5):2253-63
12193690
J Biol Chem. 1992 Feb 5;267(4):2802-9
1370833
Virology. 2006 Jan 20;344(2):328-39
16216295
Pediatr Infect Dis J. 2003 Feb;22(2 Suppl):S6-10; discussion S10-2
12671447
Genes Cells. 2001 Jun;6(6):545-57
11442634
J Exp Med. 1992 Dec 1;176(6):1693-702
1460426
J Virol. 2003 Nov;77(21):11842-5
14557668
Biochem Biophys Res Commun. 2001 Apr 27;283(1):255-9
11322797
J Virol. 2003 Feb;77(4):2321-9
12551969
J Leukoc Biol. 2004 Feb;75(2):163-89
14525967
Semin Respir Crit Care Med. 2007 Apr;28(2):171-81
17458771
Pediatr Infect Dis J. 2003 Feb;22(2 Suppl):S58-64; discussion S64-5
12671454
J Gen Virol. 2000 Oct;81(Pt 10):2341-2364
10993923
J Immunol. 1995 Aug 1;155(3):1079-90
7543512
J Interferon Cytokine Res. 2005 Dec;25(12):733-44
16375601
Immunity. 2007 Aug;27(2):240-52
17723216
Nat Med. 1999 Aug;5(8):919-23
10426316
Am J Respir Cell Mol Biol. 2010 Apr;42(4):404-14
19502390
APMIS. 2003 Jul-Aug;111(7-8):741-55
12974776
J Allergy Clin Immunol. 2004 Jan;113(1):127-33
14713917
Am J Respir Cell Mol Biol. 2004 Jun;30(6):893-900
14722224
FEBS Lett. 2003 Jun 19;545(2-3):177-82
12804771
J Virol. 2008 Mar;82(5):2040-55
17928346
Virology. 2001 May 10;283(2):230-9
11336548
J Immunol. 2004 Jan 1;172(1):567-76
14688368