Effects of interleukin-1beta and tumor necrosis factor-alpha on expression of matrix-related genes by cultured equine articular chondrocytes.
OBJECTIVE
To determine the effects of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) on expression and regulation of several matrix-related genes by equine articular chondrocytes.


METHODS
Articular cartilage harvested from grossly normal joints of 8 foals, 6 yearling horses, and 8 adult horses.


METHODS
Chondrocytes maintained in suspension cultures were treated with various doses of human recombinant IL-1beta or TNF-alpha. Northern blots of total RNA from untreated and treated chondrocytes were probed with equine complementary DNA (cDNA) probes for cartilage matrix-related genes. Incorporation of 35S-sulfate, fluorography of 14C-proline labeled medium, zymography, and western blotting were used to confirm effects on protein synthesis.


RESULTS
IL-1beta and TNF-alpha increased steady-state amounts of mRNA of matrix metalloproteinases 1, 3, and 13 by up to 100-fold. Amount of mRNA of tissue inhibitor of metalloproteinase-1 also increased but to a lesser extent (1.5- to 2-fold). Amounts of mRNA of type-II collagen and link protein were consistently decreased in a dose-dependent manner. Amount of aggrecan mRNA was decreased slightly; amounts of biglycan and decorin mRNA were minimally affected.


CONCLUSIONS
Treatment of cultured equine chondrocytes with IL-1beta or TNF-alpha resulted in marked alterations in expression of various matrix and matrix-related genes consistent with the implicated involvement of these genes in arthritis. Expression of matrix metalloproteinases was increased far more than expression of their putative endogenous inhibitor. Results support the suggestion that IL-1beta and TNF-alpha play a role in the degradation of articular cartilage in arthritis.
Richardson
D W
DW
Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square 19348-1692, USA.
Dodge
G R
GR
D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D015153:Blotting, Western / Q000662:veterinary; D002358:Cartilage, Articular / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D019902:Chondrocytes / Q000737:chemistry / Q000502:physiology; D017364:Collagenases / Q000235:genetics / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D005470:Fluorometry / Q000662:veterinary; D015971:Gene Expression Regulation, Enzymologic; D006025:Glycosaminoglycans / Q000032:analysis; D006736:Horses / Q000235:genetics / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D007375:Interleukin-1 / Q000235:genetics / Q000502:physiology*; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000502:physiology; D053509:Matrix Metalloproteinase 13; D019278:Matrix Metalloproteinase 3 / Q000235:genetics / Q000502:physiology; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism*; D012588:Scintillation Counting; D018709:Statistics, Nonparametric; D013431:Sulfates / Q000737:chemistry; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000502:physiology*
D006025:Glycosaminoglycans; D007375:Interleukin-1; D013431:Sulfates; D014409:Tumor Necrosis Factor-alpha; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3; D020781:Matrix Metalloproteinase 1