Integrative DNA Methylation and Gene Expression Analyses Identify DNA Packaging and Epigenetic Regulatory Genes Associated with Low Motility Sperm

In previous studies using candidate gene approaches, low sperm count (oligospermia) has been associated with altered sperm mRNA content and DNA methylation in both imprinted and non-imprinted genes. We performed a genome-wide analysis of sperm DNA methylation and mRNA content to test for associations with sperm function. (NCBI 1788). There was a trend among altered expression of these epigenetic regulatory genes and RPMM DNA methylation class.Using integrative genome-wide approaches we identified CpG methylation profiles and mRNA alterations associated with low sperm motility

Assisted reproduction treatment and epigenetic inheritance

Background: The subject of epigenetic risk of assisted reproduction treatment (ART), initiated by reports on an increase of children with the Beckwith–Wiedemann imprinting disorder, is very topical. Hence, there is a growing literature, including mouse studies. Methods: In order to gain information on transgenerational epigenetic inheritance and epigenetic effects induced by ART, literature databases were searched for papers on this topic using relevant keywords. Results: At the level of genomic imprinting involving CpG methylation, ART-induced epigenetic defects are convincingly observed in mice, especially for placenta, and seem more frequent than in humans. Data generally provide a warning as to the use of ovulation induction and in vitro culture. In human sperm from compromised spermatogenesis, sequence-specific DNA hypomethylation is observed repeatedly. Transmittance of sperm and oocyte DNA methylation defects is possible but, as deduced from the limited data available, largely prevented by selection of gametes for ART and/or non-viability of the resulting embryos. Some evidence indicates that subfertility itself is a risk factor for imprinting diseases. As in mouse, physiological effects from ART are observed in humans. In the human, indications for a broader target for changes in CpG methylation than imprinted DNA sequences alone have been found. In the mouse, a broader range of CpG sequences has not yet been studied. Also, a multigeneration study of systematic ART on epigenetic parameters is lacking. Conclusions: The field of epigenetic inheritance within the lifespan of an individual and between generations (via mitosis and meiosis, respectively) is growing, driven by the expansion of chromatin research. ART can induce epigenetic variation that might be transmitted to the next generation

Male 41, XXY* mice as a model for Klinefelter syndrome: Hyperactivation of Leydig cells

Sex chromosome imbalance in males is linked to a supernumerary X chromosome, a condition resulting in Klinefelter syndrome (KS; 47, XXY). KS patients suffer from infertility, hypergonadotropic hypogonadism, and cognitive impairments. Mechanisms of KS pathophysiology are poorly understood and require further exploration using animal models. Therefore, we phenotypically characterized 41, XX(Y)* mice of different ages, evaluated observed germ cell loss, studied X-inactivation, and focused on the previously postulated impaired Leydig cell maturation and function as a possible cause of the underandrogenization seen in KS. Xist methylation analysis revealed normal X-chromosome inactivation similar to that seen in females. Germ cell loss was found to be complete and to occur during the peripubertal phase. Significantly elevated FSH and LH levels were persistent in 41, XX(Y)* mice of different ages. Although Leydig cell hyperplasia was prominent, isolated XX(Y)* Leydig cells showed a mature mRNA expression profile and a significantly higher transcriptional activity compared with controls. Stimulation of XX(Y)* Leydig cells in vitro by human chorionic gonadotropin indicated a mature LH receptor whose maximal response exceeded that of control Leydig cells. The hyperactivity of Leydig cells seen in XX(Y)* mice suggests that the changes in the endocrine milieu observed in KS is not due to impaired Leydig cell function. We suggest that the embedding of Leydig cells into the changed testicular environment in 41 XX(Y)* males as such influences their endocrine function