title: Hypomethylation and Genetic Instability in Monosomy Blastocysts May Contribute to Decreased Implantation Potential.
abstract: DNA methylation is a key epigenetic mechanism responsible for gene regulation, chromatin remodeling, and genome stability, playing a fundamental role during embryonic development. The aim of this study was to determine if these epigenetic marks are associated with chromosomal aneuploidy in human blastocysts. Surplus, cryopreserved blastocysts that were donated to research with IRB consent were chosen with varying chromosomal aneuploidies and respective implantation potential: monosomies and trisomies 7, 11, 15, 21, and 22. DNA methylation analysis was performed using the Illumina Infinium HumanMethylation450 BeadChip (~485,000 CpG sites). The methylation profiles of these human blastocysts were found to be similar across all samples, independent of chromosome constitution; however, more detailed examination identified significant hypomethylation in the chromosome involved in the monosomy. Real-time PCR was also performed to determine if downstream messenger RNA (mRNA) was affected for genes on the monosomy chromosome. Gene dysregulation was observed for monosomy blastocysts within significant regions of hypo-methylation (AVEN, CYFIP1, FAM189A1, MYO9A, ADM2, PACSIN2, PARVB, and PIWIL3) (P < 0.05). Additional analysis was performed to examine the gene expression profiles of associated methylation regulators including: DNA methyltransferases (DNMT1, DNMT3A, DNMT3B, DNMT3L), chromatin modifying regulators (CSNK1E, KDM1, PRKCA), and a post-translational modifier (PRMT5). Decreased RNA transcription was confirmed for each DNMT, and the regulators that impact DNMT activity, for only monosomy blastocysts (P < 0.05). In summary, monosomy blastocysts displayed hypomethylation for the chromosome involved in the error, as well as transcription alterations of associated developmental genes. Together, these modifications may be contributing to genetic instability and therefore be responsible for the limited implantation potential observed for full monosomy blastocysts.
authors.affiliation: National Foundation for Fertility Research, Lone Tree, Colorado, 80124, United States of America.|School of Biosciences, University of Kent, Canterbury, CT2 7NJ, United Kingdom.
authors.forename: Blair R
authors.initials: BR
authors.lastname: McCallie
authors.affiliation: National Foundation for Fertility Research, Lone Tree, Colorado, 80124, United States of America.|School of Biosciences, University of Kent, Canterbury, CT2 7NJ, United Kingdom.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Parks
authors.affiliation: National Foundation for Fertility Research, Lone Tree, Colorado, 80124, United States of America.
authors.forename: Alyssa L
authors.initials: AL
authors.lastname: Patton
authors.affiliation: School of Biosciences, University of Kent, Canterbury, CT2 7NJ, United Kingdom.
authors.forename: Darren K
authors.initials: DK
authors.lastname: Griffin
authors.affiliation: Colorado Center for Reproductive Medicine, Lone Tree, Colorado, 80124, United States of America.
authors.forename: William B
authors.initials: WB
authors.lastname: Schoolcraft
authors.affiliation: National Foundation for Fertility Research, Lone Tree, Colorado, 80124, United States of America.|Colorado Center for Reproductive Medicine, Lone Tree, Colorado, 80124, United States of America.
authors.forename: Mandy G
authors.initials: MG
authors.lastname: Katz-Jaffe
mesh_terms: D000782:Aneuploidy; D001755:Blastocyst / Q000473:pathology; D025063:Chromosome Disorders / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation / Q000235:genetics*; D010064:Embryo Implantation / Q000235:genetics*; D044127:Epigenesis, Genetic; D005260:Female; D015870:Gene Expression; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D042822:Genomic Instability / Q000235:genetics; D006801:Humans; D009006:Monosomy / Q000235:genetics / Q000473:pathology; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D014314:Trisomy / Q000235:genetics / Q000473:pathology