Fertility Relevance Probability Analysis Shortlists Genetic Markers for Male Fertility Impairment

The Application of Ejaculate-Based Shotgun Proteomics for Male Infertility Screening

Problems with the male reproductive system are of both medical and social significance. As a rule, spermatozoa and seminal plasma proteomes are investigated separately to assess sperm quality. The current study aimed to compare ejaculate proteomes with spermatozoa and seminal plasma protein profiles regarding the identification of proteins related to fertility scores. A total of 1779, 715, and 2163 proteins were identified in the ejaculate, seminal plasma, and spermatozoa, respectively. Among these datasets, 472 proteins were shared. GO enrichment analysis of the common proteins enabled us to distinguish biological processes such as single fertilization (GO:0007338), spermatid development (GO:0007286), and cell motility (GO:0048870). Among the abundant terms for GO cellular components, zona pellucida receptor complex, sperm fibrous sheath, and outer dense fiber were revealed. Overall, we identified 139 testis-specific proteins. For these proteins, PPI networks that are common in ejaculate, spermatozoa, and seminal plasma were related to the following GO biological processes: cilium movement (GO:0003341), microtubule-based movement (GO:0007018), and sperm motility (GO:0097722). For ejaculate and spermatozoa, they shared 15 common testis-specific proteins with spermatogenesis (GO:0007283) and male gamete generation (GO:0048232). Therefore, we speculated that ejaculate-based proteomics could yield new insights into the peculiar reproductive physiology and spermatozoa function of men and potentially serve as an explanation for male infertility screening.

The human sperm proteome-Toward a panel for male fertility testing

BACKGROUND

Although male factor accounts for 40%-50% of unintended childlessness, we are far from fully understanding the detailed causes. Usually, affected men cannot even be provided with a molecular diagnosis.

OBJECTIVES

We aimed at a higher resolution of the human sperm proteome for better understanding of the molecular causes of male infertility. We were particularly interested in why reduced sperm count decreases fertility despite many normal-looking spermatozoa and which proteins might be involved.

MATERIAL AND METHODS

Applying mass spectrometry analysis, we qualitatively and quantitatively examined the proteomic profiles of spermatozoa from 76 men differing in fertility. Infertile men had abnormal semen parameters and were involuntarily childless. Fertile subjects exhibited normozoospermia and had fathered children without medical assistance.

RESULTS

We discovered proteins from about 7000 coding genes in the human sperm proteome. These were mainly known for involvements in cellular motility, response to stimuli, adhesion, and reproduction. Numbers of sperm proteins showing at least threefold deviating abundances increased from oligozoospermia (N = 153) and oligoasthenozoospermia (N = 154) to oligoasthenoteratozoospermia (N = 368). Deregulated sperm proteins primarily engaged in flagellar assembly and sperm motility, fertilization, and male gametogenesis. Most of these participated in a larger network of male infertility genes and proteins.

DISCUSSION

We expose 31 sperm proteins displaying deviant abundances under infertility, which already were known before to have fertility relevance, including ACTL9, CCIN, CFAP47, CFAP65, CFAP251 (WDR66), DNAH1, and SPEM1. We propose 18 additional sperm proteins with at least eightfold differential abundance for further testing of their diagnostic potential, such as C2orf16, CYLC1, SPATA31E1, SPATA31D1, SPATA48, EFHB (CFAP21), and FAM161A.

CONCLUSION

Our results shed light on the molecular background of the dysfunctionality of the fewer spermatozoa produced in oligozoospermia and syndromes including it. The male infertility network presented may prove useful in further elucidating the molecular mechanism of male infertility.

Genetic variants underlying spermatogenic arrests in men with non-obstructive azoospermia

Spermatogenic arrest is a severe form of non-obstructive azoospermia (NOA), which occurs in 10-15% of infertile men. Interruption in spermatogenic progression at premeiotic, meiotic, or postmeiotic stage can lead to arrest in men with NOA. Recent studies have intensively focused on defining genetic variants underlying these spermatogenic arrests by making genome/exome sequencing. A number of variants were discovered in the genes involving in mitosis, meiosis, germline differentiation and other basic cellular events. Herein, defined variants in NOA cases with spermatogenic arrests and created knockout mouse models for the related genes are comprehensively reviewed. Also, importance of gene panel-based screening for NOA cases was discussed. Screening common variants in these infertile men with spermatogenic arrests may contribute to elucidating the molecular background and designing novel treatment strategies.

Expression profiles of meiotic genes in male vs. female gonads and gametes: Insights into fertility issues

Gametes are specialized cells that, at fertilization, give rise to a totipotent zygote capable of generating an entire organism. Female and male germ cells undergo meiosis to produce mature gametes; however, sex-specific events of oogenesis and spermatogenesis contribute to specific roles of gametes in reproductive issues. We investigate the differential gene expression (DGE) of meiosis-related genes in human female and male gonads and gametes in normal and pathological conditions. The transcriptome data for the DGE analysis was obtained through the Gene Expression Omnibus repository, comprising human ovary and testicle samples of the prenatal period and adulthood, additionally to male (non-obstructive azoospermia (NOA) and teratozoospermia), and female (polycystic ovary syndrome (PCOS) and advanced maternal age) reproductive conditions. Gene ontology terms related to meiosis were associated with 678 genes, of which 17 genes in common were differentially expressed between the testicle and ovary during the prenatal period and adulthood. Except for SERPINA5 and SOX9, the 17 meiosis-related genes were downregulated in the testicle during the prenatal period and upregulated in adulthood compared to the ovary. No differences were observed in the oocytes of PCOS patients; however, meiosis-related genes were differentially expressed according to the patient’s age and maturity of the oocyte. In NOA and teratozoospermia, 145 meiosis-related genes were differentially expressed in comparison to the control, including OOEP; despite no recognized role in male reproduction, OOEP was co-expressed with genes related to male fertility. Taking together, these results shed light on potential genes that might be relevant to comprehend human fertility disorders.

Motility Assessment of Ram Spermatozoa

For successful fertilisation to occur, spermatozoa need to successfully migrate through the female reproductive tract and penetrate the oocyte. Predictably, poor sperm motility has been associated with low rates of fertilisation in many mammalian species, including the ram. As such, motility is one of the most important parameters used for in vitro evaluation of ram sperm quality and function. This review aims to outline the mechanical and energetic processes which underpin sperm motility, describe changes in motility which occur as a result of differences in sperm structure and the surrounding microenvironment, and assess the effectiveness of the various methods used to assess sperm motility in rams. Methods of subjective motility estimation are convenient, inexpensive methods widely used in the livestock industries, however, the subjective nature of these methods can make them unreliable. Computer-assisted sperm analysis (CASA) technology accurately and objectively measures sperm motility via two-dimensional tracing of sperm head motion, making it a popular method for sperm quality assurance in domesticated animal production laboratories. Newly developed methods of motility assessment including flagellar tracing, three-dimensional sperm tracing, in vivo motility assessment, and molecular assays which quantify motility-associated biomarkers, enable analysis of a new range of sperm motion parameters with the potential to reveal new mechanistic insights and improve ram semen assessment. Experimental application of these technologies is required to fully understand their potential to improve semen quality assessment and prediction of reproductive success in ovine artificial breeding programs.

Evaluation of sperm integrin α5β1 as a potential marker of fertility in humans

Sperm selection for assisted reproduction techniques is generally based on basic parameters, while key aspects of sperm competence and its journey from the deposition site to the fertilization site are overlooked. Consequently, identifying molecular markers in spermatozoa that can efficiently predict the fertility of a semen sample could be of great interest, particularly in cases of idiopathic male infertility. When spermatozoa reach the female reproductive tract, it provides to them the cellular and molecular microenvironment needed to acquire fertilizing ability. In this sense, considering the role that integrin α5β1 of spermatozoa plays in reproduction-related events, we investigated the correlation between the subcellular localization of sperm integrin α5β1 and early embryo development outcome after in vitro fertilization (IVF) procedures in human. Twenty-four semen samples from normozoospermic men and metaphase II (MII) oocytes from healthy women aged under 38 years, from couples who underwent IVF cycles, were used in this work. Sperm α5β1 localization was evaluated by immunofluorescence assay using an antibody against integrin α5 subunit. Integrin α5β1 was mainly localized in the sperm acrosomal region (45.33±7.89%) or the equatorial segment (30.12±7.43%). The early embryo development rate (data obtained from the Fertility Center) correlated positively with the localization of α5β1 in the acrosomal region (number of usable embryos / inseminated oocytes: ρ = 0.75; p<0.01 and number of usable embryos/total number of two pronuclear zygotes: ρ = 0.80; p<0.01). However, this correlation was not significant when the equatorial segment mark was evaluated. In addition, human sperm released from co-culture with bovine oviductal epithelial cells (BOEC) showed a significant enrichment in the acrosomal localization pattern of α5β1 compared to those sperm that were not co-cultured with BOEC (85.20±5.35% vs 35.00±17.09%, respectively, p<0.05). In conclusion, the evaluation of sperm integrin α5β1 immunolocalization could be a useful tool to select sperm with fertilizing ability from human semen samples before IVF procedures.

White paper: Onco-fertility in pediatric patients with Wilms tumor

The survival of childhood Wilms tumor is currently around 90%, with many survivors reaching reproductive age. Chemotherapy and radiotherapy are established risk factors for gonadal damage and are used in both COG and SIOP Wilms tumor treatment protocols. The risk of infertility in Wilms tumor patients is low but increases with intensification of treatment including the use of alkylating agents, whole abdominal radiation or radiotherapy to the pelvis. Both COG and SIOP protocols aim to limit the use of gonadotoxic treatment, but unfortunately this cannot be avoided in all patients. Infertility is considered one of the most important late effects of childhood cancer treatment by patients and their families. Thus, timely discussion of gonadal damage risk and fertility preservation options is important. Additionally, irrespective of the choice for preservation, consultation with a fertility preservation (FP) team is associated with decreased patient and family regret and better quality of life. Current guidelines recommend early discussion of the impact of therapy on potential fertility. Since most patients with Wilms tumors are prepubertal, potential FP methods for this group are still considered experimental. There are no proven methods for FP for prepubertal males (testicular biopsy for cryopreservation is experimental), and there is just a single option for prepubertal females (ovarian tissue cryopreservation), posing both technical and ethical challenges. Identification of genetic markers of susceptibility to gonadotoxic therapy may help to stratify patient risk of gonadal damage and identify patients most likely to benefit from FP methods.

Mutations in Hsp90 Cochaperones Result in a Wide Variety of Human Disorders

The Hsp90 molecular chaperone, along with a set of approximately 50 cochaperones, mediates the folding and activation of hundreds of cellular proteins in an ATP-dependent cycle. Cochaperones differ in how they interact with Hsp90 and their ability to modulate ATPase activity of Hsp90. Cochaperones often compete for the same binding site on Hsp90, and changes in levels of cochaperone expression that occur during neurodegeneration, cancer, or aging may result in altered Hsp90-cochaperone complexes and client activity. This review summarizes information about loss-of-function mutations of individual cochaperones and discusses the overall association of cochaperone alterations with a broad range of diseases. Cochaperone mutations result in ciliary or muscle defects, neurological development or degeneration disorders, and other disorders. In many cases, diseases were linked to defects in established cochaperone-client interactions. A better understanding of the functional consequences of defective cochaperones will provide new insights into their functions and may lead to specialized approaches to modulate Hsp90 functions and treat some of these human disorders.

Recent Progress in Spermatology Contributing to the Knowledge and Conservation of Rare and Endangered Species

There is a remarkable diversity in the animal kingdom regarding mechanisms underlying the production, maturation, structure, and function of sperm cells. Spermatology studies contribute to the knowledge of species diversity and also provide information about individual or population fitness. Furthermore, this fundamental research is required before collected spermatozoa can be used for conservation breeding, including assisted reproduction and cryobanking. This article aims to (a) review the most recent knowledge on sperm morphology and function in wild animal species, (b) analyze how this knowledge can be used to save species in their natural habitat or ex situ, and (c) propose future scientific directions in wildlife spermatology that could positively impact animal conservation. Variations in sperm structure and performance within and between species have multiple origins and significance. This collective body of knowledge enables the design and implementation of conservation strategies and action plans that integrate several disciplines. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 10 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A rare Y-autosome translocation found in a patient with nonobstructive azoospermia: Case report

Y‑autosome translocations are relatively uncommon in humans, with t(Y;1) stated to be even rarer. On the contrary, pericentric inversion 9 is the most commonly seen inversion  of chromosome . Although considered to have no significant effect on male fertility, the literature reporting on reproductive risks for both aberrations remains controversial. We report here, as far as we know, the first case of a unique combination of balanced reciprocal translocation t(Y;1) with pericentric inversion of chromosome 9 in a patient with nonobstructive azoospermia (NOA) and an otherwise normal phenotype. Our patient was a 37-year-old Caucasian male sent to our Department due to azoospermia reported by semen analysis. The cytogenetic analysis revealed a balanced reciprocal translocation including chromosomes Y and 1 in all observed metaphases: 46, X,t(Y;1)(q12;q21) and a pericentric inversion of chromosome 9: inv(9)(p12q13). By performing metaphase FISH, the t(Y;1) translocation was confirmed. By means of multiplex-PCR, no Y-chromosome microdeletions were detected in the AZF regions. This report demonstrates a unique karyotype showing balanced reciprocal translocation t(Y;1)(q12;q21) with pericentric inversion 9: inv(9)(p12q13), in a patient with NOA, and highlights the importance of appropriate genetic counseling for patients with regard to the medical management of balanced chromosomal aberrations.