title: Exposure of preimplantation embryos to insulin alters expression of imprinted genes.
abstract: Insulin promotes early embryonic development, but whether this action affects postimplantation fetal development and alters the expression of imprinted genes remain to be determined. This study analyzed the expression and methylation levels of the growth-related imprinted genes H19 and insulin-like growth factor 2 (Igf2) in fetuses exposed to insulin before implantation. We cultured 2-cell embryos in either 0 or 0.25 microg/ml insulin until the blastocyst stage and then transferred them into pseudopregnant recipient mice. The number of embryos developing to blastocysts after insulin exposure was 16.4% higher than that of the control, and the birth body weight of the insulin-exposed group was 17.8% higher than that of the control group. Real-time reverse transcription-polymerase chain reaction analysis revealed that exposure of preimplantation embryos to insulin increased the mRNA expression of both Igf2 and H19 in embryonic day (E) 14 fetuses. Bisulfite genomic sequencing demonstrated that the methylation level of the H19-Igf2 imprint control region was 19.3% lower in insulin-exposed E14 fetuses than in controls. The present study indicates that insulin exposure during the preimplantation stage alters the expression of imprinted genes and affects fetal development.
authors.affiliation: Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Wei-Juan
authors.initials: WJ
authors.lastname: Shao
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Tao
authors.forename: Jian-Yun
authors.initials: JY
authors.lastname: Xie
authors.forename: Cheng
authors.initials: C
authors.lastname: Gao
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Hu
authors.forename: Ru-Qian
authors.initials: RQ
authors.lastname: Zhao
mesh_terms: D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000187:drug effects*; D018899:CpG Islands; D019175:DNA Methylation / Q000187:drug effects; D010064:Embryo Implantation; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D018392:Genomic Imprinting / Q000187:drug effects*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000737:chemistry / Q000235:genetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000378:metabolism; D022661:RNA, Untranslated / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: C094335:H19 long non-coding RNA; D007004:Hypoglycemic Agents; C513121:IGF2 protein, mouse; D007328:Insulin; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D022661:RNA, Untranslated; D007335:Insulin-Like Growth Factor II