TY - JOUR
T1 - Prolonged tumor necrosis factor α primes fibroblast-like synoviocytes in a gene-specific manner by altering chromatin
AU - Sohn, Christopher
AU - Lee, Angela
AU - Qiao, Yu
AU - Loupasakis, Konstantinos
AU - Ivashkiv, Lionel B.
AU - Kalliolias, George D.
N1 - Publisher Copyright:
Copyright © 2015 by the American College of Rheumatology.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - Objective During the course of rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) are chronically exposed to an inflammatory milieu.Methods FLS obtained from RA patients were exposed to TNFα for 3 days and were then stimulated with interferons (IFNs). Expression of IFN target genes was measured by real-time quantitative reverse transcription-polymerase chain reaction analysis and enzyme-linked immunosorbent assay. Total STAT-1 protein and IFN-mediated STAT-1 activation were evaluated by Western blotting. Total histone levels, histone acetylation, and NF-κB p65 and RNA polymerase II (Pol II) recruitment were measured at the CXCL10 promoter (encodes IFNγ-inducible 10-kd protein [IP-10]) by chromatin immunoprecipitation assays.Results Prolonged pre-exposure of FLS to TNFα enhanced the magnitude and extended the kinetics of CXCL10/IP-10, CXCL9, and CXCL11 production upon subsequent IFN stimulation. This phenotype was retained over a period of days, even after the removal of TNFα. Prolonged TNFα exposure decreased histone levels, increased acetylation of the remaining histones, and heightened recruitment of NF-κB p65 and Pol II to the CXCL10 promoter. In parallel, an increase in intracellular STAT-1 led to amplification of IFN-induced STAT-1 activation.Conclusion Our study reveals a novel pathogenic function of TNFα, namely, prolonged and gene-specific priming of FLS for enhanced transcription of inflammatory chemokine genes due to the priming of chromatin, the sustained activation of NF-κB, and the amplification of STAT-1 activation downstream of IFNs. These data also suggest that FLS gain an "inflammatory memory" upon prolonged exposure to TNFα.
AB - Objective During the course of rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) are chronically exposed to an inflammatory milieu.Methods FLS obtained from RA patients were exposed to TNFα for 3 days and were then stimulated with interferons (IFNs). Expression of IFN target genes was measured by real-time quantitative reverse transcription-polymerase chain reaction analysis and enzyme-linked immunosorbent assay. Total STAT-1 protein and IFN-mediated STAT-1 activation were evaluated by Western blotting. Total histone levels, histone acetylation, and NF-κB p65 and RNA polymerase II (Pol II) recruitment were measured at the CXCL10 promoter (encodes IFNγ-inducible 10-kd protein [IP-10]) by chromatin immunoprecipitation assays.Results Prolonged pre-exposure of FLS to TNFα enhanced the magnitude and extended the kinetics of CXCL10/IP-10, CXCL9, and CXCL11 production upon subsequent IFN stimulation. This phenotype was retained over a period of days, even after the removal of TNFα. Prolonged TNFα exposure decreased histone levels, increased acetylation of the remaining histones, and heightened recruitment of NF-κB p65 and Pol II to the CXCL10 promoter. In parallel, an increase in intracellular STAT-1 led to amplification of IFN-induced STAT-1 activation.Conclusion Our study reveals a novel pathogenic function of TNFα, namely, prolonged and gene-specific priming of FLS for enhanced transcription of inflammatory chemokine genes due to the priming of chromatin, the sustained activation of NF-κB, and the amplification of STAT-1 activation downstream of IFNs. These data also suggest that FLS gain an "inflammatory memory" upon prolonged exposure to TNFα.
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U2 - 10.1002/art.38871
DO - 10.1002/art.38871
M3 - Article
C2 - 25199798
AN - SCOPUS:84919940967
SN - 2326-5191
VL - 67
SP - 86
EP - 95
JO - Arthritis and Rheumatology
JF - Arthritis and Rheumatology
IS - 1
ER -