Alterations in sperm DNA methylation patterns at imprinted loci in two classes of infertility.
OBJECTIVE
To evaluate the associations between proper protamine incorporation and DNA methylation at imprinted loci.


METHODS
Experimental research study.


METHODS
Research laboratory.


METHODS
Three populations were tested-abnormal protamine patients, oligozoospermic patients, and fertile donors.


METHODS
The CpG methylation patterns were examined at seven imprinted loci sequenced: LIT1, MEST, SNRPN, PLAGL1, PEG3, H19, and IGF2.


METHODS
The DNA methylation patterns were analyzed using bisulfite sequencing. The percentage of methylation was compared between fertile and infertile patients displaying abnormal protamination.


RESULTS
At six of the seven imprinted genes, the overall DNA methylation patterns at their respective differentially methylated regions were significantly altered in both infertile patient populations. When comparing the severity of methylation alterations among infertile patients, the oligozoospermic patients were significantly affected at mesoderm-specific transcript (MEST), whereas abnormal protamine patients were affected at KCNQ1, overlapping transcript 1 (LIT1), and at small nuclear ribonucleoprotein polypeptide N (SNRPN).


CONCLUSIONS
Patients with male factor infertility had significantly increased methylation alteration at six of seven imprinted loci tested, with differences in significance observed between oligozoospermic and abnormal protamine patients. This could suggest that risk of transmission of epigenetic alterations may be different with diagnoses. However, this study does not provide a causal link for epigenetic inheritance of imprinting diseases, but does show significant association between male factor infertility and alterations in sperm DNA methylation at imprinted loci.
Hammoud
Saher Sue
SS
Andrology and IVF Laboratories, Division of Urology, Department of Surgery, School of Medicine, University of Utah, Salt Lake City, Utah 84108, USA.
Purwar
Jahnvi
J
Pflueger
Christian
C
Cairns
Bradley R
BR
Carrell
Douglas T
DT
D018899:CpG Islands / Q000235:genetics; D004247:DNA / Q000032:analysis / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics*; D056426:Genetic Loci / Q000235:genetics*; D018392:Genomic Imprinting / Q000235:genetics*; D006801:Humans; D007248:Infertility, Male / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D008297:Male; D009845:Oligospermia / Q000235:genetics / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics; D011479:Protamines / Q000378:metabolism; D011506:Proteins / Q000235:genetics; D013094:Spermatozoa / Q000737:chemistry; D055517:snRNP Core Proteins / Q000235:genetics
C035170:IGF2 protein, human; C485621:KCNQ1OT1 long non-coding RNA, human; D051741:Kruppel-Like Transcription Factors; C490820:PEG3 protein, human; D024642:Potassium Channels, Voltage-Gated; D011479:Protamines; D011506:Proteins; C526417:SNRPN protein, human; C103637:mesoderm specific transcript protein; D055517:snRNP Core Proteins; D007335:Insulin-Like Growth Factor II; D004247:DNA