TENT5D disruption causes oligoasthenoteratozoospermia and male infertility

Molecular insights into sperm head shaping and its role in human male fertility

BACKGROUND

Sperm head shaping, controlled by the acrosome-acroplaxome-manchette complex, represents a significant morphological change during spermiogenesis and involves numerous proteins expressed in a spatially and temporally specific manner. Defects in sperm head shaping frequently lead to teratozoospermia concomitant with oligozoospermia and asthenozoospermia, but the pathogenic mechanism underlying sperm head shaping, and its role in male infertility, remain poorly understood.

OBJECTIVE AND RATIONALE

This review aims to summarize the mechanism underlying sperm head shaping, reveal the relationship between gene defects associated with sperm head shaping and male infertility in humans and mice, and explore potential clinical improvements in ICSI treatment.

SEARCH METHODS

We searched the PubMed database for articles published in English using the keyword 'sperm head shaping' in combination with the following terms: 'acrosome formation', 'proacrosomal vesicles (PAVs)', 'manchette', 'perinuclear theca (PT)', 'chromatin condensation', 'linker of nucleoskeleton and cytoskeleton (LINC) complex', 'histone-to-protamine (HTP) transition', 'male infertility', 'ICSI', and 'artificial oocyte activation (AOA)'. The selected publications until 1 August 2024 were critically summarized, integrated, and thoroughly discussed, and the irrelevant literature were excluded.

OUTCOMES

A total of 6823 records were retrieved. After careful screening, integrating relevant literature, and excluding articles unrelated to the topic of this review, 240 articles were ultimately included in the analysis. Firstly, we reviewed the important molecular events and structures integral to sperm head shaping, including PAV formation to fusion, acrosome attachment to the nucleus, structure and function of the manchette, PT, chromatin condensation, and HTP transition. Then, we set forth human male infertility associated with sperm head shaping and identified genes related to sperm head shaping resulting in teratozoospermia concomitant with oligozoospermia and asthenozoospermia. Finally, we summarized the outcomes of ICSI in cases of male infertility resulting from mutations in the genes associated with sperm head shaping, as well as the ICSI outcomes through AOA for infertile men with impaired sperm head.

WIDER IMPLICATIONS

Understanding the molecular mechanisms of sperm head shaping and its relationship with human male infertility holds profound clinical implications, which may contribute to risk prediction, genetic diagnosis, and the potential treatment of human male infertility.

Genetic Underpinnings of Oligoasthenoteratozoospermia

Oligoasthenoteratozoospermia (OAT) is a frequent but severe type of male infertility. As one of the most multifaceted male infertility resulting from sperm problems, its genetic etiology remains unknown in most cases. In this review, we systematically sort out the latest literature on clinical reports and animal models leading to OAT, summarise the expression profiles of causative genes for OAT, and highlight the important role of the protein transport system during spermiogenesis, spermatid cell-specific genes, Golgi and acrosome-related genes, manchette-related genes, HTCA-related genes, and axoneme-related genes in OAT development. These causative genes would be instrumental in genetic etiological screening, genetic counseling, and pre-implantation genetic testing of patients with clinical OAT.

Comprehensive analysis of poly(A) tails in mouse testes and ovaries using Nanopore Direct RNA Sequencing

Gametogenesis is a process in which dysfunctions lead to infertility, a growing health and social problem worldwide. In both spermatogenesis and oogenesis, post-transcriptional gene expression regulation is crucial. Essentially, all mRNAs possess non-templated poly(A) tails, whose composition and dynamics (elongation, shortening, and modifications) determine the fate of mRNA. Moreover, gametogenesis, especially oogenesis, represents a unique instance of the complexity of poly(A) tails metabolism, with oocyte-specific waves of cytoplasmic polyadenylation. In this context, we provide a comprehensive transcriptomic dataset focusing on mRNA poly(A) tail composition and dynamics in murine testes and ovaries. It consists of RNA samples isolated from wild-type and transgenic mice lacking TENT5 polymerases, which can extend poly(A) tails in the cytoplasm. TENT5 deficiencies have serious consequences. For instance, the defect of TENT5D causes infertility in humans. The data described here are generated mainly using the Oxford Nanopore Direct RNA Sequencing (DRS) method, which provides ground-truth information about mRNA molecules, including poly(A) tail length and nucleotide content. For instance, we show the prevalence of uridilated tails in testicular mRNAs.

Cep78 knockout causes sterility and oligoasthenoteratozoospermia in male mice

Oligoasthenoteratozoospermia (OAT) is a common cause of infertility among males, and the majority of cases of idiopathic OAT are thought to be attributed to genetic defects. In this study, the role of the CEP78 protein in spermatogenesis was initially investigated using Cep78 knockout (Cep78-/-) mice. Notably, the male Cep78-/- mice exhibited the OAT phenotype and sterility. To elucidate the mechanisms underlying the functions of the Cep78 gene in spermatogenesis, the histomorphology of germ cells was investigated during different stages of mitosis, meiosis, and spermiogenesis. Apoptotic assays and RNA-sequencing analyses were additionally performed using the testicular tissue samples of control and Cep78-/- mice. The findings strongly suggested that defects in the Cep78 gene can lead to male infertility with OAT and that the CEP78 protein is essential for acrosomal biogenesis, sperm head shaping, and formation of flagella during spermiogenesis. The findings are expected to expand the spectrum of genetic defects in OAT and enhance the accuracy of genetic screening and clinical diagnosis.

Human asthenozoospermia: Update on genetic causes, patient management, and clinical strategies

BACKGROUND

In mammals, sperm fertilization potential relies on efficient progression within the female genital tract to reach and fertilize the oocyte. This fundamental property is supported by the flagellum, an evolutionarily conserved organelle, which contains dynein motor proteins that provide the mechanical force for sperm propulsion and motility. Primary motility of the sperm cells is acquired during their transit through the epididymis and hyperactivated motility is acquired throughout the journey in the female genital tract by a process called capacitation. These activation processes rely on the micro-environment of the genital tracts. In particular, during capacitation, a panoply of ion transporters located at the surface of the sperm cells mediate complex ion exchanges, which induce an increase in plasma membrane fluidity, the alkalinization of the cytoplasm and protein phosphorylation cascades that are compulsory for sperm hyperactivation and fertilization potential. As a consequence, both structural and functional defects of the sperm flagellum can affect sperm motility, resulting in asthenozoospermia, which constitutes the most predominant pathological condition associated with human male infertility.

OBJECTIVES

Herein, we have performed a literature review to provide a comprehensive description of the recent advances in the genetics of human asthenozoospermia.

RESULTS AND DISCUSSION

We describe the currently knowledge on gene mutations that affect sperm morphology and motility, namely, asthenoteratozoospermia; we also specify the gene mutations that exclusively affect sperm function and activation, resulting in functional asthenozoospermia. We discuss the benefit of this knowledge for patient and couple management, in terms of genetic counselling and diagnosis of male infertility as a sole phenotype or in association with ciliary defects. Last, we discuss the current strategies that have been initiated for the development of potential therapeutical and contraceptive strategies targeting genes that are essential for sperm function and activation.

Genetic etiological spectrum of sperm morphological abnormalities

PURPOSE

Male infertility manifests in the form of a reduction in sperm count, sperm motility, or the loss of fertilizing ability. While the loss of sperm production can have mixed reasons, sperm structural defects, cumulatively known as teratozoospermia, have predominantly genetic bases. The aim of the present review is to undertake a comprehensive analysis of the genetic mutations leading to sperm morphological deformities/teratozoospermia.

METHODS

We undertook literature review for genes involved in sperm morphological abnormalities. The genes were classified according to the type of sperm defects they cause and on the basis of the level of evidence determined by the number of human studies and the availability of a mouse knockout.

RESULTS

Mutations in the SUN5, CEP112, BRDT, DNAH6, PMFBP1, TSGA10, and SPATA20 genes result in acephalic sperm; mutations in the DPY19L2, SPATA16, PICK1, CCNB3, CHPT1, PIWIL4, and TDRD9 genes cause globozoospermia; mutations in the AURKC gene cause macrozoospermia; mutations in the WDR12 gene cause tapered sperm head; mutations in the RNF220 and ADCY10 genes result in small sperm head; mutations in the AMZ2 gene lead to vacuolated head formation; mutations in the CC2D1B and KIAA1210 genes lead to pyriform head formation; mutations in the SEPT14, ZPBP1, FBXO43, ZCWPW1, KATNAL2, PNLDC1, and CCIN genes cause amorphous head; mutations in the SEPT12, RBMX, and ACTL7A genes cause deformed acrosome formation; mutations in the DNAH1, DNAH2, DNAH6, DNAH17, FSIP2, CFAP43, AK7, CHAP251, CFAP65, ARMC2 and several other genes result in multiple morphological abnormalities of sperm flagella (MMAF).

CONCLUSIONS

Altogether, mutations in 31 genes have been reported to cause head defects and mutations in 62 genes are known to cause sperm tail defects.

Varicocele repair for severe oligoasthenoteratozoospermia: Scoping review of published guidelines, and systematic review of the literature

Background

The outcomes of varicocele repair (VR) for severe oligozooasthenoteratozoospermia (OAT) have not been widely examined.

Methods

Assessment of outcomes of VR after severe OAT, employing scoping review of published guidelines, and systematic review of literature. The Newcastle-Ottawa scale appraised the quality of included studies. Findings from both reviews were used to identify knowledge gaps and ways to enhance the evidence base.

Results

No published guidelines exist specifically on VR for severe OAT. Of 731 articles retrieved, 15 were included, indicating a scarcity of studies appraising the topic. Most included studies exhibited high risk of bias and low-level evidence. Studies focused on basic sperm parameters; fewer examined hormonal/testicular volume changes, or pregnancy/live births. Studies suggested some post-VR sperm parameters improvements but mostly no changes in hormone levels/testicular volume. We identified four knowledge gaps: methodological issues; narrow scope of research and measurement aspects; lack of genetic considerations; and scarce economic/cost-effectiveness appraisals. We propose some precautions, remedies, and research questions to enhance the thin evidence base.

Conclusions

VR for severe OAT has potential to improve sperm parameters. Scarcity of studies, high risk of bias, low-level evidence, and other limitations mitigate against drawing solid conclusions. Future research is required.

Novel variations in TENT5D lead to teratozoospermia in infertile patients

PURPOSE

Teratozoospermia is the main pathogenic factor of male infertility. However, the genetic etiology of teratozoospermia is largely unknown. This study aims to clarify the relationship between novel variations in TENT5D and teratozoospermia in infertile patients.

MATERIALS AND METHODS

Two infertile patients were enrolled. Routine semen analysis of patients and normal controls was conducted with the WHO guidelines. Whole-exome sequencing (WES) was conducted to identify pathogenic variants in the two patients. Morphology and ultrastructure analysis of spermatozoa in the two patients was determined by Papanicolaou staining, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The functional effect of the identified variants was analyzed by immunofluorescence staining and western blotting. The expression of TENT5D in different germ cells was detected by immunofluorescence staining.

RESULTS

Two new hemizygous variations, c.101C > T (p.P34L) and c.125A > T (p.D42V), in TENT5D were detected in two patients with male infertility. Morphology analysis showed abnormalities in spermatozoa morphology in the two patients, including multiple heads, headless, multiple tails, coiled, and/or bent flagella. Ultrastructure analysis showed that most of the spermatozoa exhibited missing or irregularly arranged '9+2' structures. Further functional experiments confirmed the abrogated TENT5D protein expression in patients. In addition, both p.P34L and p.D42V substitutions resulted in a conformational change of the TENT5D protein. We precisely analyzed the subcellular localization of TENT5D in germ cells in humans and mice. And we found that TENT5D was predominantly detected in the head and flagellum of elongating spermatids and epididymal spermatozoa.

CONCLUSIONS

Our results showed further evidence of a relationship between TENT5D mutation and human male infertility, providing new genetic insight for use in the diagnosis and treatment of male infertility.

A hemizygous loss-of-function variant in BCORL1 is associated with male infertility and oligoasthenoteratozoospermia

Oligoasthenoteratozoospermia (OAT) is a common type of male infertility; however, its genetic causes remain largely unknown. Some of the genetic determinants of OAT are gene defects affecting spermatogenesis. BCORL1 (BCL6 corepressor like 1) is a transcriptional corepressor that exhibits the OAT phenotype in a knockout mouse model. A hemizygous missense variant of BCORL1 (c.2615T > G:p.Val872Gly) was reported in an infertile male patient with non-obstructive azoospermia (NOA). Nevertheless, the correlation between BCORL1 variants and OAT in humans remains unknown. In this study, we used whole-exome sequencing to identify a novel hemizygous nonsense variant of BCORL1 (c.1564G > T:p.Glu522*) in a male patient with OAT from a Han Chinese family. Functional analysis showed that the variant produced a truncated protein with altered cellular localization and a dysfunctional interaction with SKP1 (S-phase kinase-associated protein 1). Further population screening identified four BCORL1 missense variants in subjects with both OAT (1 of 325, 0.31%) and NOA (4 of 355, 1.13%), but no pathogenic BCORL1 variants among 362 fertile subjects. In conclusion, our findings indicate that BCORL1 is a potential candidate gene in the pathogenesis of OAT and NOA, expanded its disease spectrum and suggested that BCORL1 may play a role in spermatogenesis by interacting with SKP1.

TENT5-mediated polyadenylation of mRNAs encoding secreted proteins is essential for gametogenesis in mice

Cytoplasmic polyadenylation plays a vital role in gametogenesis; however, the participating enzymes and substrates in mammals remain unclear. Using knockout and knock-in mouse models, we describe the essential role of four TENT5 poly(A) polymerases in mouse fertility and gametogenesis. TENT5B and TENT5C play crucial yet redundant roles in oogenesis, with the double knockout of both genes leading to oocyte degeneration. Additionally, TENT5B-GFP knock-in females display a gain-of-function infertility effect, with multiple chromosomal aberrations in ovulated oocytes. TENT5C and TENT5D both regulate different stages of spermatogenesis, as shown by the sterility in males following the knockout of either gene. Finally, Tent5a knockout substantially lowers fertility, although the underlying mechanism is not directly related to gametogenesis. Through direct RNA sequencing, we discovered that TENT5s polyadenylate mRNAs encoding endoplasmic reticulum-targeted proteins essential for gametogenesis. Sequence motif analysis and reporter mRNA assays reveal that the presence of an endoplasmic reticulum-leader sequence represents the primary determinant of TENT5-mediated regulation.

Exploring the Mechanism of Yiwei Decoction in the Intervention of a Premature Ovarian Insufficiency Rat Based on Network Pharmacology and the miRNA-mRNA Regulatory Network

OBJECTIVE

our aim is to explore the mechanism of action of Yiwei decoction (YWD) in addressing premature ovarian insufficiency (POI) through a combination of transcriptomics and network pharmacology. By doing so, we hope to identify important pathways of action, key targets, and active components that contribute to the efficacy of YWD.

MATERIALS AND METHODS

group A comprised of the model + traditional Chinese medicine group, while group B was the model control group and group C was the normal control group. After gavage, serum AMH and E2 levels were measured by using ELISA. HE staining was used to study the impact of YWD on ovarian follicle recovery in POI rats. Additionally, RNA-seq sequencing technology was employed to analyze the transcription levels of mRNAs and miRNAs in the ovarian tissues of each group, and the resulting data were examined using R. YWD used UPLC-Q-TOF-HRMS to analyze its active ingredients. Upon obtaining the sequencing results, the miRWalk database was utilized to forecast the targets of DEmiRNAs. Network pharmacology was then applied to predict the targets of active ingredients present in YWD, ultimately constructing a regulatory network consisting of active ingredients-mRNA-miRNA. The coexpression relationship between mRNAs and miRNAs was calculated using the Pearson correlation coefficient, and high correlation coefficients between miRNA-mRNA were confirmed through miRanda sequence combination.

RESULTS

the application of YWD resulted in improved serum levels of AMH and E2, as well as an increased number of ovarian follicles in rats with POI. However, there was a minimal impact on the infiltration of ovarian lymphocytes. Through GSEA pathway enrichment analysis, we found that YWD may have a regulatory effect on PI3K-Akt, ovarian steroidogenesis, and protein digestion and absorption, which could aid in the treatment of POI. Additionally, our research discovered a total of 6 DEmiRNAs between groups A and B, including 2 new DEmiRNAs. YWD contains 111 active compounds, and our analysis of the active component-mRNA regulatory network revealed 27 active components and 73 mRNAs. Furthermore, the coexpression network included 5 miRNAs and 18 mRNAs. Our verification of MiRanda binding demonstrated that 12 of the sequence binding sites were stable.

CONCLUSIONS

our research has uncovered the regulatory network mechanism of active ingredients, mRNA, and miRNA in YWD POI treatment. However, further research is needed to determine the effect of the active ingredients on key miRNAs and mRNAs.

Deficiency in AK9 causes asthenozoospermia and male infertility by destabilising sperm nucleotide homeostasis

BACKGROUND

Asthenozoospermia is the primary cause of male infertility; however, its genetic aetiology remains poorly understood. Adenylate kinase 9 (AK9) is highly expressed in the testes of humans and mice and encodes a type of adenosine kinase that is functionally involved in cellular nucleotide homeostasis and energy metabolism. We aimed to assess whether AK9 is involved in asthenozoospermia.

METHODS

One-hundred-and-sixty-five Chinese men with idiopathic asthenozoospermia were recruited. Whole-exome sequencing (WES) and Sanger sequencing were performed for genetic analyses. Papanicolaou staining, Haematoxylin and eosin staining, scanning electron microscopy, and transmission electron microscopy were used to observe the sperm morphology and structure. Ak9-knockout mice were generated using CRISPR-Cas9. Sperm adenosine was detected by liquid chromatography-mass spectrometry. Targeted sperm metabolomics was performed. Intracytoplasmic sperm injection (ICSI) was used to treat patients.

FINDINGS

We identified five patients harbouring bi-allelic AK9 mutations. Spermatozoa from men harbouring bi-allelic AK9 mutations have a decreased ability to sustain nucleotide homeostasis. Moreover, bi-allelic AK9 mutations inhibit glycolysis in sperm. Ak9-knockout male mice also presented similar phenotypes of asthenozoospermia. Interestingly, ICSI was effective in bi-allelic AK9 mutant patients in achieving good pregnancy outcomes.

INTERPRETATION

Defects in AK9 induce asthenozoospermia with defects in nucleotide homeostasis and energy metabolism. This sterile phenotype could be rescued by ICSI.

FUNDING

The National Natural Science Foundation of China (82071697), Medical Innovation Project of Fujian Province (2020-CXB-051), open project of the NHC Key Laboratory of Male Reproduction and Genetics in Guangzhou (KF202004), Medical Research Foundation of Guangdong Province (A2021269), Guangdong Provincial Reproductive Science Institute Innovation Team grants (C-03), and Outstanding Young Talents Program of Capital Medical University (B2205).

Adverse effects of microcystins on sperm: A systematic review

Eutrophication of water bodies can lead to cyanobacterial blooms, with the resultant release of microcystins (MCs), posing a threat to the ecosystem and human health. MCs are environmental toxins with male reproductive toxicity. However, there is a dearth of reviews focusing on sperm or spermatogenesis. In this paper, studies on sperm toxicity caused by MCs in recent 20 years were collected and summarized, aiming at revealing the toxic effects and potential mechanisms of MCs on sperm. Based on the previous findings, MCs can decline sperm quality and count, and cause malformation in vertebrates and invertebrates. The reason might be that MCs cause indirect damage to sperm through impairing the structure and function of the testis. The mechanisms of MCs-induced sperm toxicity mainly result from alterations in genetic material, abnormalities in the structure and function of sperm. The epigenetic modifications such as miRNA and piRNA were also involved in MC-LR-induced sperm damage. In conclusion, MCs exposure is harmful to sperm, but its direct effects and mechanisms on sperm are still not known, which remains a significant research direction. Our review will provide a basis for the protection of male reproductive health damage caused by microcystins.