Heterogeneous requirement of IkappaB kinase 2 for inflammatory cytokine and matrix metalloproteinase production in rheumatoid arthritis: implications for therapy.
OBJECTIVE
To investigate the potential role of IkappaB kinase 1 (IKK-1) and IKK-2 in the regulation of nuclear factor kappaB (NF-kappaB) activation and the expression of tumor necrosis factor alpha (TNFalpha), as well as interleukin-1beta (IL-1beta), IL-6, IL-8, vascular endothelial growth factor (VEGF), and matrix metalloproteinases (MMPs), in rheumatoid arthritis (RA).


METHODS
Recombinant adenoviruses expressing beta-galactosidase, dominant-negative IKK-1 and IKK-2, or IkappaBalpha were used to infect ex vivo RA synovial membrane cultures and synovial fibroblasts obtained from patients with RA undergoing joint replacement surgery, or human dermal fibroblasts, human umbilical vein endothelial cells (HUVECs), and monocyte-derived macrophages from healthy volunteers. Then, their effect on the spontaneous or stimulus-induced release of inflammatory cytokines, VEGF, and MMPs from RA synovial membrane cells was examined.


RESULTS
IKK-2 was not required for lipopolysaccharide (LPS)-induced NF-kappaB activation or TNFalpha, IL-6, or IL-8 production in macrophages, but was essential for this process in response to CD40 ligand, TNFalpha, and IL-1. In synovial fibroblasts, dermal fibroblasts, and HUVECs, IKK-2 was also required for LPS-induced NF-kappaB activation and IL-6 or IL-8 production. In RA synovial membrane cells, IKK-2 inhibition had no effect on spontaneous TNFalpha production but significantly reduced IL-1beta, IL-6, IL-8, VEGF, and MMPs 1, 2, 3, and 13.


CONCLUSIONS
Our study demonstrates that IKK-2 is not essential for TNFalpha production in RA. However, because IKK-2 regulates the expression of other inflammatory cytokines (IL-1beta, IL-6, and IL-8), VEGF, and MMPs 1, 2, 3, and 13, which are involved in the inflammatory, angiogenic, and destructive processes in the RA joint, it may still be a good therapeutic target.
Andreakos
Evangelos
E
Kennedy Institute of Rheumatology, Imperial College of Science, Technology and Medicine, London, UK.
Smith
Clive
C
Kiriakidis
Serafim
S
Monaco
Claudia
C
de Martin
Rainer
R
Brennan
Fionula M
FM
Paleolog
Ewa
E
Feldmann
Marc
M
Foxwell
Brian M
BM
D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism* / Q000628:therapy; D002478:Cells, Cultured; D017364:Collagenases / Q000096:biosynthesis / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis* / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000096:biosynthesis / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D051550:I-kappa B Kinase; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000378:metabolism; D007375:Interleukin-1 / Q000096:biosynthesis / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008222:Lymphokines / Q000096:biosynthesis / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis / Q000378:metabolism; D053509:Matrix Metalloproteinase 13; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000096:biosynthesis* / Q000378:metabolism; D009000:Monocytes / Q000166:cytology; D016328:NF-kappa B / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012867:Skin / Q000166:cytology; D013583:Synovial Membrane / Q000166:cytology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016207:Cytokines; D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D008222:Lymphokines; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1