Increased sperm aneuploidy in two male carriers of germline TP53 mutations

Dapagliflozin Mitigated Elevated Disomic and Diploid Sperm in a Mouse Model of Diabetes and Recover the Disrupted Ogg1, Parp1, and P53 Gene Expression

Increases in numerical chromosomal syndromes were observed in children of diabetic mothers. However, the effects of diabetes on male reproduction, specifically numerical chromosomal aberrations (aneuploidy), have not been studied. Furthermore, despite the increasing use of dapagliflozin for diabetes treatment, no data exists on its ability to affect aneuploidy levels in germ cells. Thus, our investigation aimed to evaluate the effects of diabetes on spontaneous sperm aneuploidy and whether treatment with dapagliflozin influences the frequency of aneuploidy in the sperm of an experimental diabetic animal model. Our findings show that dapagliflozin has no aneugenic effects on the meiotic stages of spermatogenesis. In contrast, diabetes raised the frequency of aneuploidy, and dapagliflozin administration decreased the elevated levels of disomic and diploid sperm. The level of oxidative stress was markedly increased in diabetic mice, but were reduced by dapagliflozin treatment. Furthermore, the expression of some of DNA repair genes was disrupted in diabetic animals, whereas dapagliflozin therapy restored these disruptions and significantly enhanced DNA repair. Thus, dapagliflozin may effectively ameliorate diabetes-induced aneugenic effects on male meiosis and treating diabetic patients with dapagliflozin may effectively mitigate the transmission of diabetes-induced chromosomal defects to offspring.

Could exposure to spaceflight cause mutations in genes that affect male fertility?

Recently, a study reported that upon analyzing blood samples from 14 astronauts that flew Space Transportation System missions between 1998 and 2001, 34 somatic nonsynonymous single nucleotide variants were detected in 17 CH-driver genes. Of interest is that the cohort consisted of relatively young astronauts, 85% of which were males of reproductive age. Having investigated the genes with nonsynonymous substitutes from the literature, it was found that twelve of these 17 genes appear to play essential roles in male reproduction. Changes in telomere length and gene regulation were also reported in another study conducted on an astronaut during a long duration stay on the International Space Station. Realizing the impact of spaceflight on gene sequence with potential influence on male fertility, it is important that more studies are conducted in this field. Specifically, in light of ultimately colonizing space, multi-generational survival is crucial and strategies to mitigate or counteract such effects should be explored.

Chromothripsis: potential origin in gametogenesis and preimplantation cell divisions. A review

OBJECTIVE

To review the discovery of chromothripsis and analyze its impact on human reproduction.

DESIGN

Database and literature analysis.

SETTING

University hospital.

PATIENT(S)

Carriers of massive and complex chromosomal rearrangements.

INTERVENTION(S)

Cytogenetic analysis and molecular testing (fluorescence in situ hybridization, microarray, whole-genome sequencing).

MAIN OUTCOME MEASURE(S)

Chromothripsis occurrence in human gametes and preimplantation embryos, with regard to the potential causative mechanisms described in literature.

RESULT(S)

Databases were searched for the literature published up to March 2014. Chromothripsis is characterized by the shattering of one (or a few) chromosome segments followed by a haphazard reassembly of the fragments generated, arising through a single initial catastrophic event. Several mechanisms involving abortive apoptosis, telomere erosion, mitotic errors, micronuclei formation, and p53 inactivation might cause chromothripsis. The remarkable point is that all these plausible mechanisms have been identified in the field of human reproduction as causal factors for reproductive failures and the genesis of chromosomal abnormalities. Specific features of gametogenesis and early embryonic development such as the weakness of cell cycle and mitosis checkpoints and the rapid kinetics of division in germ cells and early cleavage embryos may contribute to the emergence of chromothripsis.

CONCLUSION(S)

The discovery of this new class of massive chromosomal rearrangement has deeply modified our understanding on the genesis of complex genomic rearrangements. Data presented in this review support the assumption that chromothripsis could operate in human germlines and during early embryonic development. Chromothripsis might arise more frequently than previously thought in both gametogenesis and early human embryogenesis.