Specific transgenerational imprinting effects of the endocrine disruptor methoxychlor on male gametes.
Endocrine-disrupting chemicals (EDCs), among which methoxychlor (MXC), have been reported to affect the male reproductive system. This study evaluates the possible deleterious effects of MXC on imprinted genes. After administration of the chemical in adult male mice or in pregnant mice we analyzed by pyrosequencing possible methylation defects in two paternally imprinted (H19 and Meg3 (Gtl2)) and three maternally imprinted (Mest (Peg1), Snrpn, and Peg3) genes in the sperm and in the tail, liver, and skeletal muscle DNAs of the adult male mice and of the male offspring. MXC treatment of adult mice decreased the percentages of methylated CpGs of Meg3 and increased those of Mest, Snrpn, and Peg3 in the sperm DNA. MXC treatment of pregnant mice decreased the mean sperm concentrations by 30% and altered the methylation pattern of all the imprinted genes tested in the F1 offspring. In the latter case, MXC effects were transgenerational but disappeared gradually from F1 to F3. MXC did not affect imprinting in the somatic cells, suggesting that it exerts its damaging effects via the process of reprogramming that is unique to gamete development. A systematic analysis at the CpG level showed a heterogeneity in the CpG sensitivity to MXC. This observation suggests that not only DNA methylation but also other epigenetic modifications can explain the transgenerational effects of MXC. The reported effects of EDCs on human male spermatogenesis might be mediated by complex imprinting alterations analogous to those described in this study.
Department of Genetic and Laboratory Medicine, Geneva University Hospital, 1211 Geneva 14, Switzerland.
Christelle
C
Stouder
Ariane
A
Paoloni-Giacobino
D000818:Animals; D018899:CpG Islands / Q000235:genetics; D004247:DNA / Q000235:genetics; D019175:DNA Methylation / Q000187:drug effects*; D052244:Endocrine Disruptors / Q000633:toxicity*; D057890:Epigenomics; D005260:Female; D018392:Genomic Imprinting / Q000187:drug effects*; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D008297:Male; D008731:Methoxychlor / Q000633:toxicity*; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011506:Proteins / Q000235:genetics; D062085:RNA, Long Noncoding; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism
D052244:Endocrine Disruptors; D051741:Kruppel-Like Transcription Factors; C422882:MEG3 non-coding RNA, mouse; D009687:Nuclear Proteins; C097901:Peg3 protein, mouse; D011506:Proteins; D062085:RNA, Long Noncoding; C486713:SNURF protein, mouse; C103637:mesoderm specific transcript protein; D004247:DNA; D008731:Methoxychlor