Comparative analysis of cathepsin L, cathepsin D, and collagenase messenger RNA expression in synovial tissues of patients with rheumatoid arthritis and osteoarthritis, by in situ hybridization.
OBJECTIVE
To compare the expression of cathepsin L, cathepsin D, and collagenase messenger RNA (mRNA) in synovial specimens from patients with rheumatoid arthritis (RA) and osteoarthritis (OA).


METHODS
The expression of cathepsins L and D as well as collagenase mRNA in synovial tissues from 8 patients with RA, 6 patients with OA, and 2 patients with noninflamed joints was evaluated using in situ hybridization with digoxigenin-labeled RNA probes.


RESULTS
Both RA and OA synovial tissue expressed cathepsins L and D as well as collagenase mRNA. The expression of the cathepsins was markedly higher in interstitial regions and, to some extent, in perivascular infiltrates of RA synovial tissue compared with OA specimens.


CONCLUSIONS
Cathepsins L and D mRNA are expressed differently in RA and OA synovial tissues, supporting the concept that these enzymes may contribute to the influx of mononuclear cells into RA synovium. Moreover, the data reveal that the expression of collagenase and cathepsins in RA and OA synovial lining is otherwise largely similar, and suggest that the adhesion of synovial cells to cartilage mediates the invasive destructive process in RA.
Keyszer
G M
GM
University of Alabama, Department of Medicine, Birmingham 35294-0006, USA.
Heer
A H
AH
Kriegsmann
J
J
Geiler
T
T
Trabandt
A
A
Keysser
M
M
Gay
R E
RE
Gay
S
S
D001172:Arthritis, Rheumatoid / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology; D002402:Cathepsin D / Q000096:biosynthesis / Q000235:genetics; D056668:Cathepsin L; D002403:Cathepsins / Q000096:biosynthesis / Q000235:genetics*; D002448:Cell Adhesion; D017364:Collagenases / Q000096:biosynthesis / Q000235:genetics*; D003546:Cysteine Endopeptidases / Q000096:biosynthesis / Q000235:genetics; D010450:Endopeptidases; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D017403:In Situ Hybridization; D010003:Osteoarthritis / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D013583:Synovial Membrane / Q000201:enzymology* / Q000473:pathology / Q000502:physiology
D012333:RNA, Messenger; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L; D002402:Cathepsin D; D017364:Collagenases