NF-kappa B mediates the stimulation of cytokine and chemokine expression by human articular chondrocytes in response to fibronectin fragments.
Fibronectin fragments (FN-f) that bind to the alpha(5)beta(1) integrin stimulate chondrocyte-mediated cartilage destruction and could play an important role in the progression of arthritis. The objective of this study was to identify potential cytokine mediators of cartilage inflammation and destruction induced by FN-f and to investigate the mechanism of their stimulation. Human articular chondrocytes, isolated from normal ankle cartilage obtained from tissue donors, were treated with a 110-kDa FN-f in serum-free culture, and expression of various cytokine genes was analyzed by cDNA microarray and by a cytokine protein array. Compared with untreated control cultures, stimulation by FN-f resulted in a >2-fold increase in IL-6, IL-8, MCP-1, and growth-related oncogene beta (GRO-beta). Constitutive and FN-f-inducible expression of GRO-alpha and GRO-gamma were also noted by RT-PCR and confirmed by immunoblotting. Previous reports of IL-1beta expression induced by FN-f were also confirmed, while TNF expression was found to be very low. Inhibitor studies revealed that FN-f-induced stimulation of chondrocyte chemokine expression was dependent on NF-kappaB activity, but independent of IL-1 autocrine signaling. The ability of FN-f to stimulate chondrocyte expression of multiple proinflammatory cytokines and chemokines suggests that damage to the cartilage matrix is capable of inducing a proinflammatory state responsible for further progressive matrix destruction, which also includes the chemoattraction of inflammatory cells. Targeting the signaling pathways activated by FN-f may be an effective means of inhibiting production of multiple mediators of cartilage destruction.
Pulai
Judit I
JI
Department of Internal Medicine, Section of Rheumatology, Rush Medical College, Chicago, IL 60612, USA.
Chen
Hong
H
Im
Hee-Jeong
HJ
Kumar
Sanjay
S
Hanning
Charles
C
Hegde
Priti S
PS
Loeser
Richard F
RF
D002358:Cartilage, Articular / Q000166:cytology / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D002478:Cells, Cultured; D018925:Chemokines / Q000096:biosynthesis* / Q000235:genetics; D019902:Chondrocytes / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D005353:Fibronectins / Q000502:physiology*; D020869:Gene Expression Profiling; D006801:Humans; D039081:Integrin alpha5beta1 / Q000502:physiology; D007375:Interleukin-1 / Q000502:physiology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D009842:Oligopeptides / Q000502:physiology; D010446:Peptide Fragments / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018925:Chemokines; D016207:Cytokines; D005353:Fibronectins; D039081:Integrin alpha5beta1; D007375:Interleukin-1; D016328:NF-kappa B; D009842:Oligopeptides; D010446:Peptide Fragments; C047981:arginyl-glycyl-aspartic acid; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases