Investigating the relationship between BRCA1 and BRCA2 genes methylation profile and sperm DNA fragmentation in infertile men

Abstract

The purpose of the study was to investigate whether the promoter methylation status of BRCA1 and BRCA2 DNA repair genes is associated with sperm DNA fragmentation (sDF) in infertile men with oligoasthenoteratozoospermia (OAT) which emerges due to various reasons and is effective in male infertility. Seventy‐three infertile men with OAT and 20 normozoospermic volunteers participated in the study. To investigate sDF and methylation patterns of BRCA1 and BRCA2 gene promoters, TUNEL assay and methylation‐specific PCR (MS‐PCR) were used. The mean sDF ratio for the patients was calculated as 22.50%. The calculated cut‐off value for sDF ratio was 17.0% in ROC curve analysis. Regarding sDF, a significant difference between the normozoospermic group and the OAT group with abnormal semen parameters (p < 0.001) was found. sDF demonstrated a significant effect on the semen parameters and negative correlations on sDF ratios and sperm motility, concentration and morphology. There was no statistically significant association between sDF and the methylation status of the promoter of either BRCA1 or BRCA2 genes. In routine clinical practice, sperm DNA integrity should be investigated before applying assisted reproductive techniques. To understand better the relationship between epigenetic regulation of DNA repair genes and male infertility, additional studies are required.

Epigenetics of Male Infertility: The Role of DNA Methylation

“…High methylation levels of the DNA repair X-ray repair cross-complementing protein 1 gene have been found in OAT males, thereby suggesting that the improper methylation of this gene may have a role in sperm chromatin condensation and OAT (Metin Mahmutoglu et al, 2021). Contrariwise, two additional well-known DNA repair genes, i.e., breast cancer type 1 susceptibility protein (BRCA1) and BRCA2, did not show defective methylation in infertile men with OAT (Kabartan et al, 2019). Several other genes found aberrantly methylated in altered sperm samples from infertile males have been investigated at a single-study level (Table 1).…”

Association of XRCC1 and ERCC2 promoters’ methylation with chromatin condensation and sperm DNA fragmentation in idiopathic oligoasthenoteratozoospermic men

“…ling step, terminal deoxynucleotidyl transferase (TdT) enzyme was utilised for adding fluorescein isothiocyanate-deoxyuridine triphosphate (FITC-dUTP) to 3'-hydroxyl (OH) ss-and dsDNA break sites. In the last step of the TUNEL assay, spermatozoa were counterstained with an anti-fade including DAPI(Kabartan et al, 2019). A negative control without TdT enzyme and a positive control pre-treated with 200 mM H 2 O 2 for an hour were employed in each run.Slides were immediately visualised under a fluorescent microscope at 400X magnification (Olympus BX-51).…”

“…DNA fragmentation may result from various exogenous factors including cigarette smoking, varicocele, cancer, irradiation and advanced age Kabartan et al, 2019) and has been proposed to be specifically associated with elevated levels of male infertility and pregnancy loss (Zini et al, 2001). Germ cells have various DNA repair mechanisms to protect the genomic integrity and to provide the full transmission of genetic information to the next generations properly (González-Marín et al, 2012;Gunes et al, 2015).…”

DNA methylation in human sperm: a systematic review

“…Other studies, in contrast, found no association between aberrant DNA methylation of PEG1/MESTand oligozoospermia (Marques et al, 2004). Kabartan et al (2019) found no association between oligozoospermia and DNA methylation of breast cancer gene 1 and 2 (BRCA1 and BRCA2). Tang et al (2018) found that male subfertility, whether or not semen samples were oligozoospermic, was associated with DNA methylation defects in imprinted genes, including H19.…”