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Urokinase‐type plasminogen activator and its inhibitor secreted by cultured human monocyte‐macrophages
Author(s) -
Saksela Olli,
Hovi Tapani,
Vaheri Antti
Publication year - 1985
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041220119
Subject(s) - plasminogen activator , monocyte , plasmin , urokinase , microbiology and biotechnology , cell culture , secretion , chemistry , biochemistry , biology , endocrinology , medicine , immunology , enzyme , genetics
Human blood monocytes 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 (α 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 α 2 M, 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 α 2 M or the PA inhibitor. Dexamethasone also inhibited the morphological differentiation of the cells when added to the monocyte‐phase cells.