Interleukin-1alpha treatment of meniscal explants stimulates the production and release of aggrecanase-generated, GAG-substituted aggrecan products and also the release of pre-formed, aggrecanase-generated G1 and m-calpain-generated G1-G2.
Pro-inflammatory cytokines induce meniscal matrix degradation and inhibition of endogenous repair mechanisms, but the pathogenic mechanisms behind this are mostly unknown. Therefore, we investigated details of interleukin-1 (IL-1alpha)-induced aggrecan turnover in mature meniscal tissue explants. Fibro-cartilagenous disks (3 mm diameter x 1 mm thickness) were isolated from the central, weight-bearing region of menisci from 2-year-old cattle. After 3 or 6 days of IL-1alpha-treatment, GAG loss (DMMB assay), biosynthetic activity ([(35)SO(4)]-sulfate and [(3)H]-proline incorporation), gene expression (quantitative RT-PCR) and the abundance (zymography, Western blot) of matrix-degrading enzymes and specific aggrecan products were determined. Meniscal fibrocartilage had a 4-fold lower GAG content (per wet weight) than adjacent articular cartilage, and expressed MMPs-1, -2, -3 and ADAMTS4 constitutively, whereas ADAMTS5 m-RNA was essentially undetectable. Significant IL-1 effects were a decrease in biosynthetic activity, an increase in GAG release and in the expression/abundance of MMP-2, MMP-3 and ADAMTS4. Fresh tissue contained aggrecan core protein products similar to those previously described for bovine articular cartilage of this age. IL-1 induced the release of aggrecanase-generated CS-substituted products including both high (>250 kDa) and low molecular weight (about 75 kDa) species. TIMP-3 (but not TIMP-1 and -2 or a broad spectrum MMP inhibitor) inhibited IL-1-dependent GAG loss. In addition, IL-1 induced the release of preformed pools of three known G1-bearing products. We conclude that aggrecanases are responsible for IL-1-stimulated GAG release from meniscal explants, and that IL-1 also stimulates release of G1-bearing products, by a process possibly involving hyaluronan fragmentation.
Lemke
Angelika K
AK
Institute of Anatomy, Christian-Albrechts-Universität Kiel, Kiel, Germany.
Sandy
John D
JD
Voigt
Henning
H
Dreier
Rita
R
Lee
Jennifer H
JH
Grodzinsky
Alan J
AJ
Mentlein
Rolf
R
Fay
Jakob
J
Schünke
Michael
M
Kurz
Bodo
B
D051722:ADAM Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D000071121:ADAMTS4 Protein; D053674:Aggrecans / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001168:Arthritis / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology; D002154:Calpain / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D010450:Endopeptidases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism* / Q000494:pharmacology; D053582:Interleukin-1alpha / Q000378:metabolism* / Q000494:pharmacology; D020782:Matrix Metalloproteinases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008592:Menisci, Tibial / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D008954:Models, Biological; D011348:Procollagen N-Endopeptidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
D053674:Aggrecans; D006025:Glycosaminoglycans; D018836:Inflammation Mediators; D053582:Interleukin-1alpha; D012333:RNA, Messenger; D019717:Tissue Inhibitor of Metalloproteinase-3; D006820:Hyaluronic Acid; D010450:Endopeptidases; D002154:Calpain; C449000:m-calpain; D051722:ADAM Proteins; D020782:Matrix Metalloproteinases; D011348:Procollagen N-Endopeptidase; D000071121:ADAMTS4 Protein; C083641:aggrecanase