Synoviocytes from osteoarthritis and rheumatoid arthritis produce plasminogen activators and plasminogen activator inhibitor-1 and display u-PA receptors on their surface

• Published in: Life sciences (1973) Vol. 63; no. 6; pp. 441 - 453
• Main Authors: Cerinic, Marco Matucci, Generini, Sergio, Partsch, Gerald, Pignone, Alberto, Dini, Germana, Konttinen, Yrjo T., Del Rosso, Mario
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 1998
• Subjects: Arthritis, Rheumatoid - metabolism; Arthritis, Rheumatoid - pathology; Cells, Cultured; Humans; Microscopy, Electron; osteoarthritis; Osteoarthritis - metabolism; Osteoarthritis - pathology; plasminogen activator inhibitor; Plasminogen Activator Inhibitor 1 - biosynthesis; plasminogen activators; Plasminogen Activators - biosynthesis; Receptors, Cell Surface - metabolism; Receptors, Urokinase Plasminogen Activator; rheumatoid arthritis; Surface Properties; Synovial Membrane - metabolism; Synovial Membrane - ultrastructure; synoviocytes; synoviocytes; plasminogen activators; plasminogen activator inhibitor; rheumatoid arthritis; osteoarthritis
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/S0024-3205(98)00293-8

The production of plasminogen activators and their inhibitors was studied
in vitro in osteoarthritic (OA) and rheumatoid arthritic (RA) synovial fibroblasts (SF), obtained from RA and OA patients undergoing joint surgery. Subcultured SF were cultivated for 2,4, 6, 8, 10 and 13 days and the medium assayed for the presence of both plasminogen activators (PAs) and plasminogen activator inhibitor-1 (PAI-1). The presence of urokinase-Plasminogen Activator (u-PA) receptors (u-PAR) on the surface of synovial cells was investigated by radio-ligand binding assay and crosslinking and by transmission electron microscopy (TEM) of a gold-u-PA complex. Our results showed a low production of tissue-type- Plasminogen Activator (t-PA) in both OA and RA SF, but relatively high levels of u-PA, untill confluence, both in OA and in RA. SF were also able to produce plasminogen activator inhibitor in large amounts, in particular in RA since the very beginning of the culture. Receptors for u-PA were evident on both RA and OA SF. Our data show that SF
in vitro produce mainly u-PA, the most important plasminogen activator involved in tissue modifications. The demonstration of u-PA receptors on the surface of OA and RA SF represents a step forward in the understanding of the possible role of fibrinolytic and tissue destructive proteinase cascade in joint inflammation.