Sperm are a highly specialized cell type derived to deliver the paternal haploid genome to the oocyte. The epigenetic, or gene regulatory, properties and mechanisms of the sperm assist in preparation of the paternal genome to contribute to embryogenesis and the genome of the zygote. Many recent studies have addressed the issue of altered epigenetic processes in the sperm. This review evaluates the current understanding of DNA damage, chromosome aneuploidy, reduced telomere length, malformations of the centrosome, genomic imprinting errors, altered mRNA profiles, and abnormal nuclear packaging in the sperm prior to fertilization and the observed effects on embryogenesis. Attention has also been given to understanding the underlying etiology of sperm with altered epigenetic mechanisms in humans.
Aneuploidy ; Animals ; Cell Nucleus ; physiology ; Centrosome ; pathology ; DNA Damage ; physiology ; Embryonic Development ; physiology ; Epigenesis, Genetic ; Genomic Imprinting ; physiology ; Humans ; Infertility, Male ; genetics ; Male ; RNA, Messenger ; physiology ; Spermatozoa ; abnormalities ; physiology ; Telomere ; genetics

Animals ; Disease Models, Animal ; Humans ; Infertility, Male ; genetics ; physiopathology ; Male ; Mice ; Mice, Knockout

During spermiogenesis, the protamine proteins play an integral role in spermatid chromatin compaction. Recent research has focused on many facets of protamine biology, including protamine gene and protein structure/function relationships, mechanisms of protamine expression regulation and involvement of the protamines in male fertility. In this paper, we review our current understanding of the structure and function of the protamine-1 (P1) and protamine-2 (P2) proteins and genes, the expression and regulation of these genes and the relationship between the protamines and male fertility. In addition, we offer a brief outlook on future investigation into protamine proteins.
Amino Acid Sequence ; Gene Expression Regulation ; Humans ; Infertility, Male ; Male ; Molecular Sequence Data ; Protamines ; chemistry ; genetics ; metabolism ; Spermatids ; physiology ; ultrastructure

AIMTo assess whether abnormalities exist in the UBE2B gene in a population of infertile human males, and to establish biologic plausibility of any discovered mutations.

METHODSWe carried out polymerase chain reaction (PCR) amplification and sequence analysis of the 5'-untranslated region and six exons of the UBE2B gene, including flanking intronic regions, in a group of fertile and infertile men. Following the identification of a putative promoter region that contained single or dual triplet deletions within a 10-CGG repeat island, we evaluated the binding affinity of these identified polymorphisms as compared to the wild-type sequence to transcription factor SP1 using a DNA-protein gel shift assay.

RESULTSThere was a novel exonic single nucleotide polymorphism (SNP) noted in exon 4 in 5% of infertile men. In silico 3D modeling of the altered protein showed an innocuous isoleucine for valine substitution. There were no mutations noted within any of the other exons. Three novel intronic SNPs were identified within the fertile group, and seven novel intronic SNPs identified in the infertile group. The DNA-protein gel shift assay noted that both single CGG deletion and double CGG deletion bands had approximately twice the binding affinity compared to the wild-type for SP1. The negative control confirmed no non-specific protein binding.

CONCLUSIONBy themselves, a single or double CGG deletion is unlikely to pose biologic significance. However, such deletions in this suspected promoter region are associated with increased binding affinity for SP1, and might represent one of several factors required for alteration of UBE2B gene expression.

5' Untranslated Regions ; Azoospermia ; genetics ; Base Sequence ; DNA Primers ; Humans ; Male ; Mutation ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Ubiquitin-Conjugating Enzymes ; genetics

This was a cohort study of in vitro fertilization (IVF) subjects at the University of Utah, Salt Lake City (UT, USA) utilizing partner sperm. Cycles where both the hamster egg penetration test (HEPT) and semen analysis were performed within 2 years prior to IVF cycles were stratified into four groups based on a normal or an abnormal HEPT and morphology. The mean conventional and intracytoplasmic sperm injection (ICSI) fertilization rates were calculated in each group. We performed a univariate analysis on the primary outcome comparing clinically interesting subjects. We performed a cost-effectiveness analysis of a policy of HEPT versus universal ICSI in couples with an abnormal morphology. Among patients with a normal HEPT, there was no difference in the mean conventional fertilization rates between those with a normal and an abnormal morphology. There was no difference in the mean conventional fertilization rates between subjects with a normal morphology without a hamster test and those with a normal HEPT without a morphology assessment. In 1000 simulated cycles with an abnormal morphology, a policy of HEPT was cost saving compared to universal ICSI, yet produced similar fertilization rates. The HEPT is similar to the World Health Organization edition 5 (WHO-5) morphology in predicting successful conventional fertilization while allowing decreased utilization of ICSI. A policy of HEPT for males with abnormal morphology saves cost in selecting couples for a fertilization method.

Proton-pump inhibitors (PPIs) are among the most widely used drugs worldwide. PPI use has recently been linked to adverse changes in semen quality in healthy men; however, the effects of PPI use on semen parameters remain largely unknown specifically in cases with male factor infertility. We examined whether PPI use was associated with detrimental effects on semen parameters in a large population of subfertile men. We retrospectively reviewed data from 12 257 subfertile men who had visited our fertility clinic from 2003 to 2013. Patients who reported using any PPIs for >3 months before semen sample collection were included; 7698 subfertile men taking no medication served as controls. Data were gathered on patient age, medication use, and conventional semen parameters; patients taking any known spermatotoxic medication were excluded. Linear mixed-effect regression models were used to test the effect of PPI use on semen parameters adjusting for age. A total of 248 patients (258 samples) used PPIs for at least 3 months before semen collection. In regression models, PPI use (either as the only medication or when used in combination with other nonspermatotoxic medications) was not associated with statistically significant changes in semen parameters. To our knowledge, this is the largest study to compare PPI use with semen parameters in subfertile men. Using PPIs was not associated with detrimental effects on semen quality in this retrospective study.
Adult ; Case-Control Studies ; Humans ; Infertility, Male/epidemiology* ; Male ; Proton Pump Inhibitors/therapeutic use* ; Retrospective Studies ; Semen Analysis ; Sperm Count ; Sperm Motility/drug effects* ; Spermatozoa/drug effects*