Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response.
Bisphenol-A (BPA) is a nonsteroidal estrogen that is ubiquitous in the environment. The homeobox gene Hoxa10 controls uterine organogenesis, and its expression is affected by in utero BPA exposure. We hypothesized that an epigenetic mechanism underlies BPA-mediated alterations in Hoxa10 expression. We analyzed the expression pattern and methylation profile of Hoxa10 after in utero BPA exposure. Pregnant CD-1 mice were treated with BPA (5 mg/kg IP) or vehicle control on d 9-16 of pregnancy. Hoxa10 mRNA and protein expression were increased by 25% in the reproductive tract of mice exposed in utero. Bisulfite sequencing revealed that cytosine-guanine dinucleotide methylation was decreased from 67 to 14% in the promoter and from 71 to 3% in the intron of Hoxa10 after in utero BPA exposure. Decreased DNA methylation led to an increase in binding of ER-alpha to the Hoxa10 ERE both in vitro as and in vivo as determined by EMSA and chromatin immunoprecipitation, respectively. Diminished methylation of the ERE-containing promoter sequence resulted in an increase in ERE-driven gene expression in reporter assays. We identify altered methylation as a novel mechanism of BPA-induced altered developmental programming. Permanent epigenetic alteration of ERE sensitivity to estrogen may be a general mechanism through which endocrine disruptors exert their action.
Bromer
Jason G
JG
Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA.
Zhou
Yuping
Y
Taylor
Melissa B
MB
Doherty
Leo
L
Taylor
Hugh S
HS
D000818:Animals; D001559:Benzhydryl Compounds; D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000187:drug effects*; D004968:Estrogens, Non-Steroidal / Q000494:pharmacology*; D005260:Female; D020869:Gene Expression Profiling; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D038081:Organogenesis; D010636:Phenols / Q000494:pharmacology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D014599:Uterus / Q000187:drug effects* / Q000254:growth & development; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D004968:Estrogens, Non-Steroidal; D000080905:Homeobox A10 Proteins; D018398:Homeodomain Proteins; D010636:Phenols; D012333:RNA, Messenger; C092119:Hoxa10 protein, mouse; C006780:bisphenol A; D000098826:Bisphenol A Compounds