Cartilage degradation and invasion by rheumatoid synovial fibroblasts is inhibited by gene transfer of a cell surface-targeted plasmin inhibitor.
OBJECTIVE
Joint destruction in rheumatoid arthritis (RA) is a result of degradation and invasion of the articular cartilage by the pannus tissue. The present study was undertaken to examine the role of the plasminogen activation system in cartilage degradation and invasion by synovial fibroblasts and investigate a novel gene therapeutic approach using a cell surface-targeted plasmin inhibitor (ATF.BPTI).


METHODS
Adenoviral vectors were used for gene transfer. The effects of ATF.BPTI gene transfer on RA synovial fibroblast-dependent cartilage degradation were studied in vitro, and cartilage invasion was studied in vivo in the SCID mouse coimplantation model.


RESULTS
The results indicate that cartilage matrix degradation by rheumatoid synovial fibroblasts is plasmin mediated and depends on urokinase-type plasminogen activator for activation. Targeting plasmin inhibition to the cell surface of the fibroblasts by gene transfer of a cell surface-binding plasmin inhibitor resulted in a significant reduction of cartilage matrix degradation in vitro and of cartilage invasion in vivo. Compared with uninfected rheumatoid synovial fibroblasts, the mean +/-SEM cartilage degradation in vitro was reduced to 87.9+/-0.9% after LacZ gene transfer versus a reduction to 24.0+/-1.6% after ATF.BPTI gene transfer (P<0.0001). The mean +/- SEM in vivo cartilage invasion score was 3.1+/-0.4 in the control-transduced fibroblasts and 1.8+/-0.4 in the ATF.BPTI-transduced fibroblasts (P<0.05).


CONCLUSIONS
These results indicate a role of the plasminogen activation system in synovial fibroblast-dependent cartilage degradation and invasion in RA, and demonstrate an effective way to inhibit this by gene transfer of a cell surface-targeted plasmin inhibitor.
van der Laan
W H
WH
Gaubius Laboratory, The Netherlands Organization for Applied Scientific Research, Prevention and Health, and Leiden University Medical Center.
Pap
T
T
Ronday
H K
HK
Grimbergen
J M
JM
Huisman
L G
LG
TeKoppele
J M
JM
Breedveld
F C
FC
Gay
R E
RE
Gay
S
S
Huizinga
T W
TW
Verheijen
J H
JH
Quax
P H
PH
D051696:Activating Transcription Factors; D000257:Adenoviridae Infections; D000818:Animals; D000933:Antifibrinolytic Agents / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000473:pathology*; D001798:Blood Proteins / Q000235:genetics; D002358:Cartilage, Articular / Q000378:metabolism*; D005341:Fibrinolysin / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000821:virology; D015870:Gene Expression; D018014:Gene Transfer Techniques; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D013583:Synovial Membrane / Q000473:pathology; D014157:Transcription Factors / Q000235:genetics; D014162:Transfection; D014568:Urokinase-Type Plasminogen Activator / Q000494:pharmacology
D051696:Activating Transcription Factors; D000933:Antifibrinolytic Agents; D001798:Blood Proteins; D014157:Transcription Factors; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator