Ozkocer Suheyla Esra, Guler Ismail, Ugras Dikmen Asiye, Bozkurt Nuray, Varol Nuray, Konac Ece
Department of Medical Biology and Genetics, Institute of Health Sciences, Gazi University, Kavaklıdere Çankaya, 06540, Ankara, Turkey.
Department of Histology and Embryology, Faculty of Medicine, Gazi University, Besevler, 06500, Ankara, Turkey.
J Assist Reprod Genet. 2024 Sep;41(9):2289-2300. doi: 10.1007/s10815-024-03202-w. Epub 2024 Jul 17.
To investigate whether the DNA methylation profiles of GNAS(20q13.32), MEST(7q32.2), MESTIT1(7q32.2), IGF2(11p15.5), H19 (7q32.2), and CEP41(7q32.2) genes are related to the transcriptomic and epigenomic etiology of male infertility.
The DNA methylation levels of spermatozoa were obtained from fertile (n = 30), oligozoospermic (n = 30), and men with normal sperm count (n = 30). The methylation status of each CpG site was categorized as hypermethylated or hypomethylated. Expression levels of target gene transcripts were determined using real-time PCR.
The oligozoospermia showed a higher frequency of hypermethylation at GNASAS 1st, 3rd, and 5th CpG dinucleotides (66.7%, 73.3%, 73.3%) compared to the fertile group (33.3%, 33.3%, 40%, respectively). The normal sperm count exhibited a higher frequency of hypermethylation at the 3rd CpG of CEP41 (46.7%) than the fertile group (16.7%). Normal sperm count was predicted by CEP41 hypermethylation (OR = 1.750, 95%CI 1.038-2.950) and hypermethylation of both CEP41 and GNASAS (OR = 2.389, 95%CI 1.137-5.021). Oligozoospermia was predicted solely by GNASAS hypermethylation (OR = 2.460, 95%CI 1.315-4.603). In sperms with decreased IGF2 expression in the fertile group, we observed hypomethylation in the 2nd CpG of IGF2 antisense (IFG2AS), and hypermethylation in the 1st, 2nd, and 4th CpGs of H19. No significant relationship was found between IGF2 expression and methylation status of IGF2AS and H19 in infertile groups.
The disappearance of the relationship between IGF2 expression and IGF2AS and H19 methylations in the infertile group provides new information regarding the disruption of epigenetic programming during spermatogenesis. A better understanding of sperm GNASAS and CEP41 hypermethylation could advance innovative diagnostic markers for male infertility.
研究GNAS（20q13.32）、MEST（7q32.2）、MESTIT1（7q32.2）、IGF2（11p15.5）、H19（7q32.2）和CEP41（7q32.2）基因的DNA甲基化谱是否与男性不育的转录组学和表观基因组学病因相关。
从生育能力正常者（n = 30）、少精子症患者（n = 30）和精子计数正常的男性（n = 30）中获取精子的DNA甲基化水平。每个CpG位点的甲基化状态分为高甲基化或低甲基化。使用实时PCR测定靶基因转录本的表达水平。
与生育能力正常组相比，少精子症患者在GNASAS的第1、3和5个CpG二核苷酸处高甲基化的频率更高（分别为66.7%、73.3%、73.3%），而生育能力正常组分别为33.3%、33.3%、40%。精子计数正常者在CEP41的第3个CpG处高甲基化的频率（46.7%）高于生育能力正常组（16.7%）。通过CEP41高甲基化（OR = 1.750，95%CI 1.038 - 2.950）以及CEP41和GNASAS两者的高甲基化（OR = 2.389，95%CI 1.137 - 5.021）可预测精子计数正常。仅通过GNASAS高甲基化可预测少精子症（OR = 2.460，95%CI 1.315 - 4.603）。在生育能力正常组中IGF2表达降低的精子中，我们观察到IGF2反义链（IFG2AS）的第2个CpG处低甲基化，以及H19的第1、2和4个CpG处高甲基化。在不育组中未发现IGF2表达与IGF2AS和H19甲基化状态之间存在显著关系。
不育组中IGF2表达与IGF2AS和H19甲基化之间关系的消失为精子发生过程中表观遗传编程的破坏提供了新信息。更好地理解精子GNASAS和CEP41高甲基化可为男性不育的创新诊断标志物研究提供帮助。
