The interleukin-1 (IL-1) system plays an integral role in local intercellul
ar interactions during implantation. In addition, the plasminogen activator
system, especially urokinase plasminogen activator (u-PA), plasminogen act
ivator inhibitor (PAI-1), and u-PA receptor (u-PAR), are crucial during emb
ryo implantation. Decidualization and implantation are complex processes de
pendent upon several proteases, including u-PA, and IL-1 is known to affect
PA activity in several cell types. We investigated the role of IL-1 beta i
n regulating u-PA, PAI-1, u-PAR, and soluble u-PAR messenger ribonucleic ac
id (mRNA) expression in cultured human endometrial stromal cells using quan
titative competitive PCR. For confirmation of the mRNA data, we measured PA
I-1 and u-PAR protein by enzyme-linked immunosorbent assay. Confluent strom
al cell cultures treated with progesterone and estradiol for 9 days were st
imulated with IL-1 beta, and IL-1 beta plus IL-1 beta antibody for an addit
ional 24 h. Total RNA was extracted, reverse transcribed, and coamplified u
sing quantitative and competitive PCR with internal standards. IL-1 beta in
creased PAI-1, u-PAR, and soluble u-PAR expression in a dose-dependent mann
er, and this result was reversed by anti-IL-l beta antibody treatment. u-PA
mRNA expression was not dependent on IL-1 beta. These results suggest that
IL-1 may be important in regulating PAI-1 and u-PAR during stromal cell de
cidualization before implantation.