Epigenetic Dysregulation Observed in Monosomy Blastocysts Further Compromises Developmental Potential.
Epigenetic mechanisms such as DNA methylation regulate genomic imprinting and account for the distinct non-equivalence of the parental genomes in the embryo. Chromosomal aneuploidy, a major cause of infertility, distorts this highly regulated disparity by the presence or absence of chromosomes. The implantation potential of monosomy embryos is negligible compared to their trisomy counterparts, yet the cause for this is unknown. This study investigated the impact of chromosomal aneuploidy on strict epigenetically regulated domains, specifically imprinting control regions present on aneuploid chromosomes. Donated cryopreserved human IVF blastocysts of transferable quality, including trisomy 15, trisomy 11, monosomy 15, monosomy 11, and donor oocyte control blastocysts were examined individually for DNA methylation profiles by bisulfite mutagenesis and sequencing analysis of two maternally methylated imprinting control regions (ICRs), SNRPN (15q11.2) and KCNQ1OT1 (11p15.5), and one paternally methylated imprinting control region, H19 (11p15.5). Imprinted genes within the regions were also evaluated for transcript abundance by RT-qPCR. Overall, statistically significant hypermethylated and hypomethylated ICRs were found in both the trisomy and monosomy blastocysts compared to controls, restricted only to the chromosome affected by the aneuploidy. Increased expression was observed for maternally-expressed imprinted genes in trisomy blastocysts, while a decreased expression was observed for both maternally- and paternally-expressed imprinted genes in monosomy blastocysts. This epigenetic dysregulation and altered monoallelic expression observed at imprinting control regions in aneuploid IVF embryos supports euploid embryo transfer during infertility treatments, and may specifically highlight an explanation for the compromised implantation potential in monosomy embryos.
Fertility Labs of Colorado, Lone Tree, Colorado, United States of America.
Michelle M
MM
Denomme
Fertility Labs of Colorado, Lone Tree, Colorado, United States of America.
Blair R
BR
McCallie
Fertility Labs of Colorado, Lone Tree, Colorado, United States of America.
Jason C
JC
Parks
Colorado Center for Reproductive Medicine, Lone Tree, Colorado, United States of America.
William B
WB
Schoolcraft
Fertility Labs of Colorado, Lone Tree, Colorado, United States of America.|Colorado Center for Reproductive Medicine, Lone Tree, Colorado, United States of America.
Mandy G
MG
Katz-Jaffe
D000328:Adult; D001755:Blastocyst / Q000378:metabolism*; D019175:DNA Methylation; D047108:Embryonic Development; D044127:Epigenesis, Genetic; D005260:Female; D018392:Genomic Imprinting; D006801:Humans; D008423:Maternal Age; D009006:Monosomy; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D062085:RNA, Long Noncoding / Q000235:genetics*; D055517:snRNP Core Proteins / Q000235:genetics*
C094335:H19 long non-coding RNA; C485621:KCNQ1OT1 long non-coding RNA, human; D024642:Potassium Channels, Voltage-Gated; D062085:RNA, Long Noncoding; C526417:SNRPN protein, human; D055517:snRNP Core Proteins