Expression of AhR and ARNT mRNA in cultured human endometrial explants exposed to TCDD.
Endometriosis is a debilitating disease found in 10-15% of reproductive-age women and is characterized by the presence of endometrial tissue outside of the uterus. The present study characterizes the expression of AhR and ARNT mRNA in a human endometrial explant culture model in the absence and presence of TCDD exposure. In a parallel, companion study using this model, TCDD exposure was shown to induce CYP1A1 mRNA, CYP1B1 mRNA, EROD (7-ethoxyresorufin-O-deethylase) activity, and CYP1B1 protein in human endometrial explants. Explants were prepared from specimens obtained at laparoscopy or laparotomy from women undergoing surgery for tubal ligation, endometriosis, or pelvic pain unrelated to endometriosis. These specimens were a subset of the specimens used in the parallel study. The explants were cultured in medium containing 10 nM estradiol (E(2)) or 1 nM estradiol plus 500 nM progesterone (E(2) + P(4)) with or without TCDD (first 24 h). After culture, AhR and ARNT mRNA expression were quantified by RT-PCR. TCDD treatment significantly increased the expression of AhR mRNA, but not ARNT mRNA. The expression of both genes was similar for all individual explants and the ratio of AhR:ARNT mRNA expression across all samples was 1.7 to 1.8. Constitutive AhR mRNA expression was donor age dependent (increasing with age), while ARNT mRNA expression was donor age and tissue phase dependent (increased in older and proliferative phase specimens). Similar to results in the parallel study on expression of CYP1A1 mRNA, CYP1B1 mRNA, EROD activity, and CYP1B1 protein, the presence of endometriosis did not affect the expression of AhR or ARNT mRNA, either constitutively or following TCDD exposure. However, the detection of disease-specific change was limited by small sample size and variability in tissue cycle phase. The human endometrial explant culture model will be useful for future studies of the effects of dioxin-like compounds on human endometrium in relationship to cycle phase, hormonal exposure, and donor age.
Pitt
J A
JA
Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC 27599, USA.
Feng
L
L
Abbott
B D
BD
Schmid
J
J
Batt
R E
RE
Costich
T G
TG
Koury
S T
ST
Bofinger
D P
DP
D001189:Aryl Hydrocarbon Hydroxylases; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D002478:Cells, Cultured; D046508:Culture Techniques; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics; D065633:Cytochrome P-450 CYP1B1; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D004268:DNA-Binding Proteins; D004717:Endometrium / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D005260:Female; D006801:Humans; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics*; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*
C497396:ARNT protein, human; D004268:DNA-Binding Proteins; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D014157:Transcription Factors; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1