Urokinase-type plasminogen activator and its inhibitor secreted by cultured human monocyte-macrophages

✍ Scribed by Olli Saksela; Tapani Hovi; Antti Vaheri

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 872 KB
• Volume: 122
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041220119

✦ Synopsis

Human blood rnonocytes in culture differentiate to macrophagelike cells within 1 week. Coinciding with this morphological transition the cells started releasing increasing amounts of the serine proteinase plasminogen activator (PA; Mr 56,000) of the urokinase (u-PA) type and the proteinase inhibitor alpha-2-macroglobulin ( a 2 M ) . Unlike the cell-associated PA activity, which was also readily detected in fresh monocytes, the activity secreted into the serum-free culture medium could be measured only after treatment of the samples with sodium dodecyl sulphate. Heat or acid treatment of the medium was not sufficient to reveal the PA activity, suggesting that, apart from azM, another PA-inhibiting substance was present in the culture medium. The inhibitor (Mr 65,000) was found to be synthesized by macrophages and specifically inhibited u-PA activity but not tissue-type PA (t-PA) or plasmin activity. Dexamethasone decreased the secretion of PA by differentiated macrophages without affecting the production of aZM or the PA inhibitor. Dexarnethasone also inhibited the morphological differentiation of the cells when added to the rnonocyte-phase cells.