Transcriptional regulation of oxytocin receptor by interleukin-1beta and interleukin-6.
The up-regulation of oxytocin (OT) receptors in late pregnancy results principally from increased synthesis of messenger RNA. The 5'-flanking region of the human OT receptor gene contains several putative binding sites for nuclear factor-interleukin-6 (NF-IL6), also known as CAAT/enhancer binding protein-beta. This trans-acting factor modulates the expression of genes involved in acute inflammatory responses. Proinflammatory cytokines, such as IL-1beta or IL-6, have been implicated as mediators in both preterm and term labor, particularly in association with intrauterine infection. We hypothesized that IL-1beta and IL-6 induce OT receptor gene expression in human myometrial cells, and this is mediated by NF-IL6 and cognate response elements in the 5'-flanking region of the OT receptor gene. Contrary to the hypothesis, both IL-1beta and IL-6 treatment resulted in a significant decrease in OT receptor messenger RNA measured by ribonuclease protection analysis. Using electrophoretic mobility shift assay, we have shown that NF-IL6 is present at low levels that appear to be increased after treatment with either IL-1beta or IL-6. Using deletion analysis and functional transfection studies in HeLa cells, we demonstrated that the OT receptor gene promoter displays constitutive basal activity and is negatively regulated by both IL-1beta and IL-6. This suppressive ability of IL-1beta and IL-6 depends on the -1203/-722 region of the OT receptor promoter, which contains binding sites for NF-IL6, acute phase response element, and NF-kappaB. Our findings suggest a role for IL-1beta and IL-6 in the transcriptional regulation of the human OT receptor gene.
Perinatal Research Center, Department of Obstetrics and Gynecology, HMRC 220, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
B
B
Schmid
S
S
Wong
B F
BF
Mitchell
D020121:5' Untranslated Regions / Q000096:biosynthesis; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D017248:Enzyme Multiplied Immunoassay Technique; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology*; D015850:Interleukin-6 / Q000502:physiology*; D009215:Myometrium / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D018045:Receptors, Oxytocin / Q000096:biosynthesis* / Q000235:genetics*; D014162:Transfection
D020121:5' Untranslated Regions; D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D018045:Receptors, Oxytocin