Interleukin (IL)-23 p19 expression induced by IL-1beta in human fibroblast-like synoviocytes with rheumatoid arthritis via active nuclear factor-kappaB and AP-1 dependent pathway.
OBJECTIVE
To explore the source of the p19 subunit of interleukin-23 (IL-23) in joints with rheumatoid arthritis (RA), the effects of IL-1beta and tumour necrosis factor (TNF)-alpha on IL-23 gene expression in RA fibroblast-like synoviocytes and the effect of IL-23 on proinflammatory cytokines.


METHODS
Expression of IL-23 p19 in joints was examined by immunohistochemical analysis of patients with RA and osteoarthritis (OA). The effects of IL-1beta and TNF-alpha on the expression, of IL-23 p19 and IL-12 p35 subunits in human fibroblast-like synoviocytes from RA patients (HFLS-RA) were determined by reverse transcriptase polymerase chain reaction (RT-PCR), quantitative PCR and western blotting assay. Blockade of nuclear factor kappaB (NF-kappaB) or AP-1 activation was used to verify the involvement of intracellular signal pathways of the induction of p19. IL-23-induced IL-8 and IL-6 productions were determined in HFLS-RA by RT-PCR and enzyme-linked immunosorbent assay.


RESULTS
IL-23 p19 was expressed in the synovium from RA, but not from OA patients. Similar to the protein expression, IL-23 p19 mRNA could be detected by RT-PCR in four of five RA synovial fluid mononuclear cells (SFMC). IL-1beta and TNF-alpha could induce RA fibroblast-like synoviocytes to produce the IL-23 p19 subunit. The effects of IL-1beta were much stronger than TNF-alpha. These responses were observed in both a dose-responsive and time-dependent manner. IL-1beta produced weakly enhanced gene expression of the p35 subunits of IL-12. IL-1beta also promotes the p35 expression, a subunit of IL-12, but weakly. In addition, the NF-kappaB and the AP-1 inhibitors down-regulated the expression of IL-23 p19 mRNA induced by IL-1beta. IL-23 receptor (IL-23R) was of constitutive expression in HFLS-RA. Moreover, IL-23 up-regulated the IL-8 and IL-6 mRNA and protein levels in a dose-dependent manner in HFLS-RA.


CONCLUSIONS
Our results demonstrate that IL-23, produced by mononuclear cells in synovial fluid with RA and HFLS-RA, promotes inflammatory responses in RA by inducing IL-8 and IL-6 production from HFLS. IL-1beta regulates IL-23 p19 expression via NF-kappaB and AP-1 pathways. This report also demonstrates that IL-23 could promote inflammatory responses in HFLS-RA by stimulating IL-8 and IL-6 production.
Liu
F-L
FL
Graduate Institute of Medical Sciences, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Chen
C-H
CH
Chu
S-J
SJ
Chen
J-H
JH
Lai
J-H
JH
Sytwu
H-K
HK
Chang
D-M
DM
D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000473:pathology; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D020381:Interleukin-17 / Q000096:biosynthesis; D053583:Interleukin-1beta / Q000276:immunology*; D053760:Interleukin-23 Subunit p19 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D016328:NF-kappa B / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D018123:Receptors, Interleukin / Q000378:metabolism; D013582:Synovial Fluid / Q000276:immunology; D013583:Synovial Membrane / Q000276:immunology / Q000473:pathology*; D018808:Transcription Factor AP-1 / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
C515500:IL23R protein, human; D020381:Interleukin-17; D053583:Interleukin-1beta; D053760:Interleukin-23 Subunit p19; D015850:Interleukin-6; D016209:Interleukin-8; D016328:NF-kappa B; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha