title: Epigenetic heterogeneity of developmentally important genes in human sperm: implications for assisted reproduction outcome.
abstract: The molecular basis of male infertility is poorly understood, the majority of cases remaining unsolved. The association of aberrant sperm DNA methylation patterns and compromised semen parameters suggests that disturbances in male germline epigenetic reprogramming contribute to this problem. So far there are only few data on the epigenetic heterogeneity of sperm within a given sample and how to select the best sperm for successful infertility treatment. Limiting dilution bisulfite sequencing of small pools of sperm from fertile donors did not reveal significant differences in the occurrence of abnormal methylation imprints between sperm with and without morphological abnormalities. Intracytoplasmic morphologically selected sperm injection was not associated with an improved epigenetic quality, compared to standard intracytoplasmatic sperm injection. Deep bisulfite sequencing (DBS) of 2 imprinted and 2 pluripotency genes in sperm from men attending a fertility center showed that in both samples with normozoospermia and oligoasthenoteratozoospermia (OAT) the vast majority of sperm alleles was normally (de)methylated and the percentage of epimutations (allele methylation errors) was generally low (<1%). However, DBS allowed one to identify and quantify these rare epimutations with high accuracy. Sperm samples not leading to a pregnancy, in particular in the OAT group, had significantly more epimutations in the paternally methylated GTL2 gene than samples leading to a live birth. All 13 normozoospermic and 13 OAT samples leading to a child had <1% GTL2 epimutations, whereas one (7%) of 14 normozoospermic and 7 (50%) of 14 OAT samples without pregnancy displayed 1-14% GTL2 epimutations.
authors.affiliation: a Institute of Human Genetics ; Julius Maximilians University ; Würzburg , Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Kuhtz
authors.forename: Eberhard
authors.initials: E
authors.lastname: Schneider
authors.forename: Nady
authors.initials: N
authors.lastname: El Hajj
authors.forename: Lena
authors.initials: L
authors.lastname: Zimmermann
authors.forename: Olga
authors.initials: O
authors.lastname: Fust
authors.forename: Bartosz
authors.initials: B
authors.lastname: Linek
authors.forename: Rudolf
authors.initials: R
authors.lastname: Seufert
authors.forename: Thomas
authors.initials: T
authors.lastname: Hahn
authors.forename: Martin
authors.initials: M
authors.lastname: Schorsch
authors.forename: Thomas
authors.initials: T
authors.lastname: Haaf
mesh_terms: D053627:Asthenozoospermia / Q000235:genetics*; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D018392:Genomic Imprinting; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D008297:Male; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D062085:RNA, Long Noncoding / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D012016:Reference Values; D059010:Single-Cell Analysis; D013091:Spermatogenesis / Q000235:genetics; D013094:Spermatozoa / Q000502:physiology*; D013447:Sulfites
chemical_list: C481351:BOLL protein, human; D018398:Homeodomain Proteins; C485621:KCNQ1OT1 long non-coding RNA, human; D051741:Kruppel-Like Transcription Factors; C498907:MEG3 non-coding RNA, human; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3; C490820:PEG3 protein, human; C494173:POU5F1 protein, human; D024642:Potassium Channels, Voltage-Gated; D062085:RNA, Long Noncoding; D016601:RNA-Binding Proteins; D013447:Sulfites; C042345:hydrogen sulfite
keywords: ART outcome; ART, assisted reproductive technology; DBS, deep bisulfite sequencing; GTL2; ICSI; ICSI, intracytoplasmatic sperm injection; IMSI; IMSI, intracytoplasmic morphologically selected sperm injection; LD, limiting dilution; OAT, oligoasthenoteratozoospermia; PCR, polymerase chain reaction; SNP, single nucleotide polymorphism; deep bisulfite sequencing; epigenetic heterogeneity; sperm DNA methylation