F. Bigonnesse et al., Interleukin-1 receptor accessory protein is constitutively expressed in human endometrium throughout the menstrual cycle, MOL HUM REP, 7(4), 2001, pp. 333-339
Interleukin-1 (IL-1) is one of the principal cytokines that participate in
endocrine and local regulation of many endometrial and reproductive functio
ns. The cellular response to IL-1 principally implicates receptor type 1 (I
L-1R tI) and, according to recent data, an accessory protein (IL-1R-AcP) th
at seems to play an essential function in signal transduction, In the prese
nt study, we examined the expression of IL-1R-AcP in the endometrium of 39
normal fertile women throughout the menstrual cycle. As studied by immunohi
stochemistry, IL-1R-AcP was detected across endometrial tissue, but more no
ticeably in the glands and luminal epithelium. The intensity of IL-1R-AcP i
mmunostaining was consistently high throughout the menstrual cycle, and thi
s was confirmed by Western blot analysis of the protein and corroborated by
reverse transcription-polymerase chain reaction analysis of the mRNA. To o
ur knowledge, this is the first report showing that IL-1R-AcP is expressed
in endometrial tissue, and without any noticeable variation throughout the
menstrual cycle. This suggests that the accessory protein, whose co-express
ion is critical for IL-1R tI-mediated cell activation, is, in contrast to t
he functional receptor, constitutively expressed and not subject to similar
cycle-dependent regulation.