Modulations of functional activity in differentiated macrophages are accompanied by early and transient increase or...

Area of Science:

• Immunology
• Molecular Biology
• Oncogenes

Background:

• Macrophage activation involves complex gene expression changes.
• The c-fos proto-oncogene is rapidly induced by various stimuli.
• Understanding c-fos regulation is key to macrophage function.

Purpose of the Study:

• To investigate the role of c-fos gene expression in modulating macrophage activity.
• To determine how different immune modulators affect c-fos mRNA and transcription.
• To explore the regulatory mechanisms controlling c-fos gene transcription.

Main Methods:

• Cultured mouse peritoneal macrophages were treated with various agents (CT, dex, IFN-gamma, Con A, LPS).
• mRNA levels and transcription rates of c-fos, urokinase-type plasminogen activator, and tumor necrosis factor/cachectin were measured.
• Protein synthesis inhibition was used to study transcriptional control.

Main Results:

• Cholera toxin, dexamethasone, and LPS enhanced c-fos gene expression.
• Interferon-gamma and concanavalin A decreased c-fos gene expression.
• Inhibition of protein synthesis led to a transient increase in c-fos gene transcription, suggesting repressor control.

Conclusions:

• The c-fos gene product may play a role in regulating differentiated macrophage functional activity.
• c-fos gene expression is rapidly and transiently modulated by immune stimuli.
• Labile protein repressors likely control c-fos gene transcription.