PMID- 24899179 OWN - NLM STAT- MEDLINE DCOM- 20140925 LR - 20230207 IS - 1098-5514 (Electronic) IS - 0022-538X (Print) IS - 0022-538X (Linking) VI - 88 IP - 16 DP - 2014 Aug TI - The gammaherpesviruses Kaposi's sarcoma-associated herpesvirus and murine gammaherpesvirus 68 modulate the Toll-like receptor-induced proinflammatory cytokine response. PG - 9245-59 LID - 10.1128/JVI.00841-14 [doi] AB - The human pathogen Kaposi's sarcoma-associated herpesvirus (KSHV), the etiological agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease, establishes lifelong latency upon infection. Murine gammaherpesvirus 68 (MHV68) is a well-established model for KSHV. Toll-like receptors (TLRs) play a crucial role for the innate immune response to pathogens. Although KSHV and MHV68 are detected by TLRs, studies suggest they modulate TLR4 and TLR9 signaling, respectively. In this study, we show that in bone marrow-derived macrophages (BMDMs), MHV68 did not induce a detectable proinflammatory cytokine response. Furthermore, MHV68 abrogated the response to TLR2, -4, -7, and -9 agonists in BMDMs. Similarly to observations with MHV68, infection with KSHV efficiently inhibited TLR2 signaling in THP-1 monocytes. Using a KSHV open reading frame (ORF) library, we found that K4.2, ORF21, ORF31, and the replication and transcription activator protein (RTA)/ORF50 inhibited TLR2-dependent nuclear factor kappa B (NF-kappaB) activation in HEK293 TLR2-yellow fluorescent protein (YFP)- and Flag-TLR2-transfected HEK293T cells. Of the identified ORFs, RTA/ORF50 strongly downregulated TLR2 and TLR4 signaling by reducing TLR2 and TLR4 protein expression. Confocal microscopy revealed that TLR2 and TLR4 were no longer localized to the plasma membrane in cells expressing RTA/ORF50. In this study, we have shown that the gammaherpesviruses MHV68 and KSHV efficiently downmodulate TLR signaling in macrophages and have identified a novel function of RTA/ORF50 in modulation of the innate immune response. IMPORTANCE: The Toll-like receptors (TLRs) are an important class of pattern recognition receptors of the innate immune system. They induce a potent proinflammatory cytokine response upon detection of a variety of pathogens. In this study, we found that the gammaherpesviruses murine gammaherpesvirus 68 (MHV68) and Kaposi's sarcoma-associated herpesvirus (KSHV) efficiently inhibit the TLR-mediated innate immune response. We further identified the KSHV-encoded replication and transcription activator protein (RTA) as a novel modulator of TLR signaling. Our data suggest that the gammaherpesviruses MHV68 and KSHV prevent activation of the innate immune response by targeting TLR signaling. CI - Copyright (c) 2014, American Society for Microbiology. All Rights Reserved. FAU - Bussey, Kendra A AU - Bussey KA AD - Helmholtz Centre for Infection Research, Braunschweig, Germany. FAU - Reimer, Elisa AU - Reimer E AD - Helmholtz Centre for Infection Research, Braunschweig, Germany. FAU - Todt, Helene AU - Todt H AD - Helmholtz Centre for Infection Research, Braunschweig, Germany. FAU - Denker, Brigitte AU - Denker B AD - Helmholtz Centre for Infection Research, Braunschweig, Germany. FAU - Gallo, Antonio AU - Gallo A AD - Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany. FAU - Konrad, Andreas AU - Konrad A AD - Division of Molecular and Experimental Surgery, Department of Surgery, Universitatsklinikum Erlangen, Erlangen, Germany. FAU - Ottinger, Matthias AU - Ottinger M AD - Helmholtz Centre for Infection Research, Braunschweig, Germany Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany. FAU - Adler, Heiko AU - Adler H AD - Research Unit Gene Vectors, Helmholtz Zentrum Munchen-German Research Center for Environmental Health (GmbH), Munich, Germany. FAU - Sturzl, Michael AU - Sturzl M AD - Division of Molecular and Experimental Surgery, Department of Surgery, Universitatsklinikum Erlangen, Erlangen, Germany. FAU - Brune, Wolfram AU - Brune W AD - Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany. FAU - Brinkmann, Melanie M AU - Brinkmann MM AD - Helmholtz Centre for Infection Research, Braunschweig, Germany Institute of Virology, Hannover Medical School, Hannover, Germany Melanie.Brinkmann@helmholtz-hzi.de. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20140604 PL - United States TA - J Virol JT - Journal of virology JID - 0113724 RN - 0 (Cytokines) RN - 0 (NF-kappa B) RN - 0 (Toll-Like Receptors) RN - 0 (Trans-Activators) RN - 0 (Tumor Necrosis Factor-alpha) RN - 0 (Viral Proteins) SB - IM MH - Animals MH - Bone Marrow/metabolism/virology MH - Cell Line MH - Cytokines/genetics/*metabolism MH - Down-Regulation/genetics MH - Gammaherpesvirinae/*pathogenicity MH - Gene Expression Regulation, Viral/genetics MH - HEK293 Cells MH - Herpesviridae Infections/genetics/*metabolism/virology MH - Herpesvirus 8, Human/*pathogenicity MH - Humans MH - Inflammation/genetics/*metabolism/*virology MH - Macrophages/metabolism/virology MH - Mice MH - Mice, Inbred C57BL MH - Monocytes/metabolism/virology MH - NF-kappa B/genetics/metabolism MH - Open Reading Frames/genetics MH - Signal Transduction/genetics MH - Toll-Like Receptors/genetics/*metabolism MH - Trans-Activators/genetics/metabolism MH - Tumor Necrosis Factor-alpha/genetics/metabolism MH - Viral Proteins/genetics/metabolism MH - Virus Activation/genetics MH - Virus Latency/genetics PMC - PMC4136288 EDAT- 2014/06/06 06:00 MHDA- 2014/09/26 06:00 PMCR- 2015/02/01 CRDT- 2014/06/06 06:00 PHST- 2014/06/06 06:00 [entrez] PHST- 2014/06/06 06:00 [pubmed] PHST- 2014/09/26 06:00 [medline] PHST- 2015/02/01 00:00 [pmc-release] AID - JVI.00841-14 [pii] AID - 00841-14 [pii] AID - 10.1128/JVI.00841-14 [doi] PST - ppublish SO - J Virol. 2014 Aug;88(16):9245-59. doi: 10.1128/JVI.00841-14. Epub 2014 Jun 4.