Transcriptional regulation of genes encoding the acute-phase proteins CRP, SAA, and C3.

Inflammation or acute tissue injury results in a programmed change in the concentration of several plasma proteins. Among these proteins, two--C-reactive protein (CRP) and serum amyloid A protein (SAA)--increase up to 1000-fold after an acute-phase stimulus in humans and rabbits. To determine the mechanism for regulation of acute-phase gene expression, we examined changes in the rates of transcription and specific hepatic mRNA content for rabbit CRP, SAA, and some complement protein mRNA during an acute-phase response. Induction of a sterile inflammatory reaction with intramuscular injection of turpentine resulted in an increase in the hepatocellular content of CRP, SAA, C3, and factor B mRNA and the transcription of CRP, SAA, and C3 genes. These data suggest that the increase in CRP, SAA, and C3 serum concentrations observed during an acute-phase reaction is due to an increase in biosynthesis and is, at least in part, under transcriptional control.