Summary
Protein C is a precursor of the anticoagulant serine protease, activated protein C,
which inhibits coagulation factors Va and VIIIa. Although the liver appears to be
the primary site of protein C synthesis, we previously demonstrated that the kidney
and male reproductive organs also expressed abundant protein C mRNA in the mouse.
In the present study, we further investigated the effects of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and transforming growth factor-β (TGF-β) on the expression
of protein C mRNA in the principal producing organs, i.e., the liver, kidney, and
testis. Both quantitative reverse transcription-PCR assay and in situ hybridization
analysis revealed that TNF-α decreased protein C mRNA expression in the liver, kidney, and testis. IL-1 also down-regulated
protein C mRNA expression in the liver and testis, but not in the kidney. In contrast,
TGF-β unchanged the expression level of protein C mRNA in these three organs. These
observations suggest that TNF-α and IL-1 may contribute to an increase in the procoagulant potential by down-regulation
of protein C synthesis in the tissues during inflammatory processes.