Differential expression of cathepsins B and L compared with matrix metalloproteinases and their respective inhibitors in rheumatoid arthritis and osteoarthritis: a parallel investigation by semiquantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry.
OBJECTIVE
To study the expression of the cysteine proteinases cathepsin B and L and their most potent inhibitor cystatin C in the synovial membrane of patients with rheumatoid arthritis (RA) and osteoarthritis (OA) on both the messenger RNA (mRNA) level and the protein level.


METHODS
The expression of both cysteine proteinases and cystatin C was investigated in synovial tissue from 15 RA and 11 OA patients and compared with the expression of matrix metalloproteinase 1 (MMP-1; collagenase), MMP-3 (stromelysin), and tissue inhibitor of metalloproteinases 1 (TIMP-1). Expression of mRNA was analyzed by semiquantitative reverse transcriptase-polymerase chain reaction. Protein expression was evaluated by immunohistochemistry. The results were correlated with the histologic evidence of inflammatory activity.


RESULTS
A significantly more pronounced expression of MMP mRNA was observed in RA synovium compared with OA. In contrast, the mRNA expression of cysteine proteinases, as well as TIMP-1 and cystatin C, did not differ between the patient groups. However, the protein expression of both MMP and cysteine proteinases was significantly more prominent in RA synovial lining compared with OA, whereas cystatin C and TIMP-1 protein were expressed equally.


CONCLUSIONS
The data indicate a more pronounced expression of MMP mRNA compared with cysteine proteinases in RA. The higher levels of cathepsin B and L proteins in RA synovial lining cells compared with OA are consistent with previous studies that assert a post-transcriptional up-regulation of these enzymes in RA.
Keyszer
G
G
Charité University Hospital, Berlin, Germany.
Redlich
A
A
Häupl
T
T
Zacher
J
J
Sparmann
M
M
Engethüm
U
U
Gay
S
S
Burmester
G R
GR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002401:Cathepsin B / Q000378:metabolism*; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D055316:Cystatin C; D015891:Cystatins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism; D010450:Endopeptidases; D004791:Enzyme Inhibitors / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D011480:Protease Inhibitors / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D011480:Protease Inhibitors; D019715:Tissue Inhibitor of Metalloproteinase-1; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C534281:CTSL protein, human; D056668:Cathepsin L; D008666:Metalloendopeptidases