Sperm imprinting integrity in seminoma patients?

Abstract

BackgroundTesticular germ cell tumor such as seminoma is strongly associated with male reproductive problems commonly associated with the alteration of sperm parameters as described in testicular dysgenesis syndrome. Interestingly, numerous studies have reported that the precursor of germ cell cancer, germ cell neoplasia in situ (GCNIS), present similarities to fetal gonocytes, specifically characterized by global DNA hypomethylation particularly on imprinting sequences. These disorders may have a common origin derived from perturbations of embryonal programming during fetal development. Presently, there is no available information concerning the sperm DNA methylation patterns of testicular cancer patients. For the first time, we evaluated the sperm imprinting of seminoma patients.A total of 92 cryopreserved sperm samples were included, 31 before seminoma treatment (S): 23 normozoospermic (SN) and 8 oligozoospermic (SO) and 61 sperm controls samples: 31 normozoospermic (N) and 30 oligozoospermic (O). DNA methylation levels of seven differentially methylated regions (DMRs) of imprinted genes [H19/IGF2: IG-DMR (CTCF3 and CTCF6 of H19 gene); IGF2-DMRs (DMR0 and DMR2); MEG3/DLK1:IG-DMR; SNURF:TSS-DMR; KCNQ1OT1:TSS-DMR] were assessed by pyrosequencing. All comparative analyses were adjusted for age.ResultsComparisons of sperm DNA methylation levels between seminoma (S) and normozoospermic (N) samples showed a significant difference for the SNURF sequence (p = 0.017), but after taking into account the sperm parameters, no difference was observed. However, we confirmed a significant association between oligozoospermia (O) and imprinting defects for H19/IGF2-CTCF6 (p = 0.001), MEG3/DLK1 (p = 0.017), IGF2-DMR2 (p = 0.022), and SNURF (p = 0.032) in comparison with control groups (N).ConclusionsThis study highlights the high risk of sperm imprinting defects in cases of oligozoospermia and shows for the first time that seminoma patients with normal spermatogenesis present sperm imprinting integrity. These data suggest a low probability of the involvement of a common imprinting defect in fetal cells leading to both TGCT and subfertility.Electronic supplementary materialThe online version of this article (10.1186/s13148-018-0559-z) contains supplementary material, which is available to authorized users.

Epigenetics of Male Infertility: The Role of DNA Methylation

“…Contrariwise, the lack of altered methylation has been reported for PEG1, ZAC, and GTL2 in the sperm of male partners from recurrent spontaneous miscarriages (Ankolkar et al, 2013). Lastly, the maternally imprinted gene SNRPN upstream reading frame protein, which is related to the SNRPN pathway, has been detected as hypermethylated in association with oligozoospermia (Bruno et al, 2018).…”

“…(SNRPN) (Mayer et al, 2000;Higashimoto et al, 2003;Broad et al, 2009;Hammoud et al, 2010;Zheng et al, 2011;Zhao et al, 2015;Bruno et al, 2018). However, failure in the maintenance of imprinted gene methylation patterns in the germline might occur, and this has been associated with low sperm quality and pregnancy rate and impaired post-fertilization development (Rotondo et al, 2013;Kitamura et al, 2015;McSwiggin and O'Doherty, 2018).…”

“…Altered methylation in H19 has been broadly documented to be associated with infertile males affected by oligozoospermia, asthenozoospermia, teratozoospermia, OA, AT, and OAT (Marques et al, 2004(Marques et al, , 2008(Marques et al, , 2010Kobayashi et al, 2007;Boissonnas et al, 2010;Minor et al, 2011;Rotondo et al, 2013;Li et al, 2016;Dong et al, 2017;Bruno et al, 2018;Peng et al, 2018). Idiopathic infertile males with normal semen parameters have also been found to carry methylation defects at H19 in their sperm (Poplinski et al, 2010;Ankolkar et al, 2013;Tang et al, 2018).…”

“…In addition, abnormal methylation at H19 has been shown at the regulatory region CTCF-binding site 6 (CTCF6), located within the DMR of IGF2-H19, in sperm DNA from infertile males (Rotondo et al, 2013). Therefore, sperm cells carrying methylation defects at the IGF2-H19 CTCF6 region are at a high risk of causing biallelic inactivation of the IGF2 gene, which, in turn, could negatively impact embryo development and/or pregnancy outcome (Boissonnas et al, 2010;Santi et al, 2017;Bruno et al, 2018). Similarly, methylation defects at IGF2-H19 have been detected in placenta tissues from offspring conceived by assisted reproductive technologies (ART) (Pinborg et al, 2016;Hattori et al, 2019;Lou et al, 2019).…”

Minor DNA methylation changes are observed in spermatozoa prepared using different protocols

“…Additionally, ROS levels were positively correlated with the DNA fragmentation index 46 . Furthermore, alterations in IGF2 methylation were associated with sperm concentration, 47 but it was also suggested that alterations in IGF2 methylation are caused by ART and can be detected in fetuses 48 . The transgenerational impact of rearranged IGF2 methylation was studied in animal models after paternal exposure to different environmental pollutants, and it was suggested that endocrine disruptor (TCDD) exposure can cause changes in sperm IGF2 methylation, which are detected even in offspring, 49 while benzo[a]pyrene exposure did not cause such effects 50 .…”