Aberrant DNA methylation at imprinted genes in testicular sperm retrieved from men with obstructive azoospermia and undergoing vasectomy reversal

Abstract

Male factor infertility has been associated with abnormal DNA methylation at imprinted genes. Little information is available on the status of imprinting in the sperm of men with azoospermia, including the association between aberrant imprinting and obstructive azoospermia (OA) or non-OA (NOA). Analysis of DNA methylation at imprinted genes in the sperm of men undergoing vasectomy reversal would aid determination of whether aberrant imprinting is associated with obstruction. Testicular sperm was retrieved from testicular biopsies obtained from men with azoospermia (NZ18), including OA (NZ10), NOA (NZ5), and unknown pathology (NZ3), and from men undergoing vasectomy reversal (NZ17). Sperm was also obtained from proven fertile men (NZ9). DNA methylation was investigated at multiple CpG sites within the differentially methylated regions (DMRs) of three imprinted genes, H19, IG-GTL2 and MEST, using bisulphite sequencing. Unique clones representative of single cells were analyzed. We found a significant decrease in DNA methylation at the H19 DMR in testicular sperm of azoospermic men compared with proven fertile men. The decrease was also significant between OA and proven fertile men, and between men undergoing vasectomy reversal and proven fertile men, suggesting that aberrant DNA methylation may be associated with obstruction. Changes in DNA methylation at IG-GTL2 and MEST DMRs among groups were not significant. Our data suggest that imprinting abnormalities may be associated with obstruction and may occur in response to changes in testicular environment and not only spermatogenesis failure, as previously reported. Methylation at the H19 DMR was particularly prone to modification in testicular sperm.

Genomic imprinting and its relevance to congenital disease, infertility, molar pregnancy and induced pluripotent stem cell

“…[79][80][81][82][83][84][85][86] Abnormal methylation was observed in not only paternally methylated ICRs but also maternally methylated ICRs. At present, it is unclear how defects in methylation imprints are brought about in these patients, but one explanation could be aminoacid sequence variations in DNMT3L.…”

The role of epigenetics in idiopathic male infertility

“…Methylated region of long QT intronic transcript 1 (DMR-LIT1) is an imprinting control region, and its demethylation is associated with Beckwith-Wiedemann Syndrome [45]. Several studies have demonstrated a significant association between methylation statuses of both maternally and paternally imprinted genes and sperm abnormalities and are summarized in Table 1 [22,38,57,58,[62][63][64][65] (Table 1).…”

Guidance and Self‐Sorting of Active Swimmers: 3D Periodic Arrays Increase Persistence Length of Human Sperm Selecting for the Fittest

“…Even where the seminal parameters are normal, ejaculates showing sperm with high DNA damage have been reported 10, 11. Moreover, various epidemiological studies reporting the methylation status of imprinted genes of sperm from severely infertile men show a significant risk of imprinting disorders in offspring conceived by IVF and ICSI 18, 19, 20, 21, 22, 23, 24, 25, 26. These observations strongly argue that the sperm genome provides an epigenetically poised set of developmental genes that potentially have a crucial effect on embryological growth and development.…”