Interleukin-1beta stimulates placental leucine aminopeptidase/oxytocinase expression in BeWo choriocarcinoma cells.
In addition to prostaglandins, inflammatory cytokines induce uterine contraction via oxytocin (OT). Placental leucine aminopeptidase (P-LAP), an oxytocinase that is identical to cystine aminopeptidase, destroys OT activity. Patients with spontaneous preterm delivery have higher concentrations of inflammatory cytokines and lower P-LAP activities than those with normal delivery. In addition, the P-LAP promoter region contains putative binding sites for cytokine-induced transcription factors. We therefore postulated that inflammatory cytokines suppress P-LAP expression and examined this notion using BeWo choriocarcinoma cells cultured in the presence of cytokines. However, interleukin-1beta (IL-1beta) increased P-LAP activity in a time- and dose-dependent manner. Furthermore, Western blot analysis showed a dose-dependent increase of P-LAP proteins. We also detected IL-1 type I receptor mRNA in BeWo cells by RT-PCR. Semi-quantitative RT-PCR and Southern blot analysis showed that IL-1beta also increased P-LAP mRNA, which was abrogated by prior exposure to cycloheximide. Luciferase assays did not reveal any regulatory regions that could explain IL-1beta-induced P-LAP mRNA accumulation within 1.1 kb upstream of the P-LAP gene. Immunohistochemical analysis of human placenta with chorioamnionitis demonstrated prominent P-LAP staining at sites of abundant inflammatory cell infiltration. These findings indicated that prolonged exposure to IL-1beta induces P-LAP in the trophoblasts, possibly via other de-novo protein synthesis, which contradicted our initial hypothesis.
Ikoma
Yoko
Y
Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Japan.
Nomura
Seiji
S
Ito
Tomomi
T
Katsumata
Yoshinari
Y
Nakata
Masayuki
M
Iwanaga
Kumi
K
Okada
Mayumi
M
Kikkawa
Fumitaka
F
Tamakoshi
Koji
K
Nagasaka
Tetsuo
T
Tsujimoto
Masafumi
M
Mizutani
Shigehiko
S
D002822:Choriocarcinoma; D003513:Cycloheximide / Q000494:pharmacology; D010122:Cystinyl Aminopeptidase / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D017930:Genes, Reporter; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008156:Luciferases / Q000235:genetics; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics; D017472:Receptors, Interleukin-1 / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms
D007375:Interleukin-1; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D011993:Recombinant Fusion Proteins; D003513:Cycloheximide; D008156:Luciferases; D010122:Cystinyl Aminopeptidase; C105964:leucyl-cystinyl aminopeptidase