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Regulation of the plasminogen activator activity of macrophage tumor cell lines
Abstract:
Four murine monocyte-macrophage cell lines, WEHI-3, J774, RAW 264.10 and PU5-1.8, synthesize and secrete the proteolytic enzyme, plasminogen activator. Lymphocyte conditioned medium, 12-0-tetradecanoyl-phorbol-13-acetate and Concanavalin A enhance the enzyme activity of these lines, while low concentrations of anti-inflammatory glucocorticoids and also cholera toxin reduce the enzyme activity. These observations are similar to those found for mouse peritoneal exudate macrophages. It is suggested, therefore, that these cell lines might be useful models to delineate the cellular mechanisms involved in the control of the synthesis and secretion of macrophage plasminogen activator and of other macrophage secretory products, particularly those resulting from lymphocyte-macrophage interaction.
Insights
Murine macrophage cell lines secrete plasminogen activator, an enzyme whose activity is modulated by various factors. These cell lines serve as valuable models for studying macrophage secretory functions and lymphocyte-macrophage interactions.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Monocyte-macrophage cell lines are crucial for studying immune responses.
- Plasminogen activator is a key enzyme secreted by macrophages.
- Understanding macrophage secretory products is vital for immunology.
Purpose of the Study:
- To investigate the synthesis and secretion of plasminogen activator by murine macrophage cell lines.
- To explore factors influencing macrophage plasminogen activator activity.
- To establish cell line models for studying macrophage secretory mechanisms.
Main Methods:
- Utilized four murine monocyte-macrophage cell lines (WEHI-3, J774, RAW 264.10, PU5-1.8).
- Assessed plasminogen activator synthesis and secretion.
- Investigated the effects of lymphocyte conditioned medium, phorbol ester, Concanavalin A, glucocorticoids, and cholera toxin on enzyme activity.
Main Results:
- All four cell lines synthesized and secreted plasminogen activator.
- Lymphocyte conditioned medium, 12-0-tetradecanoyl-phorbol-13-acetate, and Concanavalin A enhanced enzyme activity.
- Low concentrations of glucocorticoids and cholera toxin reduced enzyme activity.
Conclusions:
- Murine macrophage cell lines mimic peritoneal exudate macrophages in plasminogen activator secretion.
- These cell lines are suitable models for dissecting cellular control of macrophage secretory products.
- The findings provide insights into lymphocyte-macrophage interactions influencing secretion.