title: Perinatal programming of adult rat germ cell death after exposure to xenoestrogens: role of microRNA miR-29 family in the down-regulation of DNA methyltransferases and Mcl-1.
abstract: Different studies have pointed out that developmental exposure to environmental endocrine disruptors can induce long-term testicular germ cell death probably through epigenetic mechanisms. By using a model of early neonatal post-natal day (PND) 1 to 5 exposure of male rats to a xenoestrogen, estradiol benzoate (EB), we investigated the role of microRNA and DNA methyltransferases (DNMT) on the developmental effects of EB on the adult germ cell death process. Neonatal exposure to EB induced adult germ cell apoptosis together with a dose-dependent increase in miR-29a, miR-29b, and miR-29c expression. Increased miR-29 expression resulted in a decrease in DNMT1, DNMT3a, and DNMT3b and antiapoptotic myeloid cell leukemia sequence 1 (Mcl-1) protein levels as shown in 1) germ cells of adult rats exposed neonatally to EB and 2) in spermatogonial GC-1 transfected with miR-29. The DNMT decrease was associated with a concomitant increase in transcript levels of DNA methylation target genes, such as L1td1-1 ORF1 and ORF2, Cdkn2a, and Gstp1, in correlation with their pattern of methylation. Finally, GC-1 cell lines transfection with miR-29a, miR-29b, or miR-29c undergo apoptosis evidenced by Annexin-V expression. Together, the increased miR-29 with a subsequent reduction in DNMT and Mcl-1 protein levels may represent a basis of explanation for the adult expression of the germ cell apoptosis phenotype. These observations suggest that the increased expression of the "apoptomir" miR-29 family represents the upstream mechanism identified until now that is involved in adult germ cell apoptosis induced by a neonatal hormonal disruption.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, Unité 1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Team 5, Nice F-06204, France.
authors.forename: Léo
authors.initials: L
authors.lastname: Meunier
authors.forename: Bénazir
authors.initials: B
authors.lastname: Siddeek
authors.forename: Aurélie
authors.initials: A
authors.lastname: Vega
authors.forename: Nadjem
authors.initials: N
authors.lastname: Lakhdari
authors.forename: Lilia
authors.initials: L
authors.lastname: Inoubli
authors.forename: Rachel Paul
authors.initials: RP
authors.lastname: Bellon
authors.forename: Géraldine
authors.initials: G
authors.lastname: Lemaire
authors.forename: Claire
authors.initials: C
authors.lastname: Mauduit
authors.forename: Mohamed
authors.initials: M
authors.lastname: Benahmed
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D000090205:DNA Methyltransferase 3A; D015536:Down-Regulation / Q000502:physiology*; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D008297:Male; D008780:Methyltransferases / Q000378:metabolism*; D035683:MicroRNAs / Q000502:physiology*; D023421:Models, Animal; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D010641:Phenotype; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000503:physiopathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013090:Spermatocytes / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D000097584:DNA Methyltransferase 3B
chemical_list: D017304:Annexin A5; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; D004958:Estradiol; D008780:Methyltransferases; D035683:MicroRNAs; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D000097584:DNA Methyltransferase 3B; C526366:MIRN29 microRNA, rat; C579093:Mcl1 protein, rat; C074283:estradiol 3-benzoate; C000619382:Dnmt1 protein, rat