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Cartilage synthesizes the serine protease inhibitor PAI‐1: Support for the involvement of serine proteases in cartilage remodeling
Author(s) -
Treadwell Benjamin V.,
Pavia Michele,
Towle Christine A.,
Cooley Ver J.,
Mankin Henry J.
Publication year - 1991
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100090302
Subject(s) - proteases , serine protease , serine , plasminogen activator , cartilage , plasminogen activator inhibitor 1 , messenger rna , northern blot , chemistry , tissue plasminogen activator , activator (genetics) , microbiology and biotechnology , biochemistry , protease , biology , endocrinology , enzyme , gene , anatomy
The work described here demonstrates the synthesis by human articular cartilage of plasminogen activator inhibitor‐1 (PAI‐1), a potent inhibitor of the serine protease tissue plasminogen activator (tPA). We also present data demonstrating an increase in PAI‐1 messenger ribonucleic acid (mRNA) in chondrocytes exposed to the cytokine interleukin‐1 (IL‐1). Interestingly, this elevation of steady‐state mRNA levels does not appear to result in an increase in synthesis of PAI‐1 protein. Northern blot analysis reveals that of the two mRNA species (3.4 kb, 2.4 kb) previously reported for PAI‐1, only the larger species (3.4 kb) appears to be synthesized by chrondrocytes. Our data demonstrate the IL‐1‐stimulated production by cartilage of tissue plasminogen activator. We also show evidence for the presence of plasminogen in cartilage. A scheme is presented indicating the probable importance of the serine proteases (tPA and plasminogen) and PAI‐1 in cartilage degradation.