Novel Mutations in X-Linked, USP26-Induced Asthenoteratozoospermia and Male Infertility

The Effect of Edaravone Supplementation Prior to Cryopreservation on Sperm Parameters, DNA Integrity, Apoptosis, Lipid Peroxidation, and Mitochondrial Membrane Potential in Infertile Men with Asthenoteratozoospermia

Male infertility is a worldwide problem, and many couples have suffered from it. Although cryopreservation is widely used for the long-term preservation of human sperm, sperm survival, and function post-thawing procedure may be strongly impaired and thus decrease the reproductive performance. This study examined whether adding Edaravone before cryopreservation could improve the post-thaw parameters (especially sperm motility) of cryopreserved spermatozoa in patients with asthenoteratozoospermia (AT). Semen samples were collected by masturbation from 25 men with AT and assessed following WHO standards. Samples were divided into three aliquots. The first aliquot remained untreated and freshly assessed (fresh group). The second aliquot was untreated, mixed with a cryopreservation medium, and cryopreserved (freeze group). The third aliquot was treated with ten µM Edaravone, mixed with cryopreservation medium, and cryopreserved (freeze + Edaravone group). The groups were assessed for motility, morphology, viability, apoptosis, lipid peroxidation, Mitochondrial Membrane Potential (MMP), DNA Fragmentation Index (DFI), glutathione (GSH), ATP, and ROS production. The freeze + Edaravone group significantly improved total sperm motility (P < 0.0001), progressive and non-progressive sperm motility (P < 0.01), viability (P < 0.0001), morphology (P < 0.001), DFI (P < 0.0001) and live sperm cells (P < 0.0001) post-thawing compared to freeze group. Additionally, the freeze + Edaravone group significantly decreased necrotic sperm cells (P < 0.0001), lipid peroxidation (P < 0.0001), and intracellular ROS production (P < 0.0001) post-thawing procedure. Furthermore, the freeze + Edaravone group significantly enhanced MMP jc-1 orange and green (P < 0.0001 and P < 0.01, respectively), ATP production (P < 0.0001), and GSH levels (P < 0.0001) post-thawing procedure compared to freeze group. Our findings proved that the freeze + Edaravone group of men with AT improved sperm survival and functions post-thawing procedure.

EP300-interacting inhibitor of differentiation 3 is required for spermatogenesis in mice

BACKGROUND

Mammalian spermatogenesis is a highly complex process of cell proliferation, meiosis, and differentiation. A series of genes are expressed in an orderly and precise manner to ensure spermatogenesis, with chromatin undergoing intricate changes throughout. EP300-interacting inhibitor of differentiation 3 (Eid3) is a testis-enriched gene, but its role in male reproduction remains unclear.

OBJECTIVE

To investigate the role of EID3 in male spermatogenesis and explore the potential underlying mechanism.

MATERIALS AND METHODS

We generated Eid3 knockout mouse model using the CRISPR-Cas9 system. We measured the expression of EID3 in mouse tissues and testicular cell populations by qRT-PCR and western blot. Histological analysis, including hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining, together with computer-assisted sperm analysis (CASA), were performed to evaluate the effect of EID3 on spermatogenesis in mice. Light and ultrastructural microscopy were used to evaluate the morphology and structure of the Eid3-/- spermatozoa. We used western blot and immunofluorescence to further analyze the function of EID3 in spermiogenesis.

RESULTS

Eid3-/- mouse showed a significant decrease in sperm count, motility, and morphology. Loss of EID3 impaired the normal meiotic process and induced apoptosis of abnormally developing spermatocytes, ultimately resulting in the decrease of sperm cell number. Additionally, EID3 deficiency led to a decrease in histone acetylation levels in spermatids, impaired histone-to-protamine transition and chromatin condensation process, and ultimately resulted in abnormal sperm morphology.

DISCUSSION AND CONCLUSIONS

This study confirms for the first time that EID3 is crucial for meiosis and chromatin condensation during spermatogenesis, and EID3 deficiency leads to a significant decrease in sperm parameters. Given the high expression paradigm of Eid3 in human testis, EID3 likely plays a role in human reproduction. Future research could provide a new target for the clinical diagnosis and treatment of male infertility.

A homozygous missense variant in YTHDC2 induces azoospermia in two siblings

Male infertility is a complex multifactorial reproductive disorder with highly heterogeneous phenotypic presentations. Azoospermia is a medically non-manageable cause of male infertility affecting ∼1% of men. Precise etiology of azoospermia is not known in approximately three-fourth of the cases. To explore the genetic basis of azoospermia, we performed whole exome sequencing in two non-obstructive azoospermia affected siblings from a consanguineous Pakistani family. Bioinformatic filtering and segregation analysis of whole exome sequencing data resulted in the identification of a rare homozygous missense variant (c.962G>C, p. Arg321Thr) in YTHDC2, segregating with disease in the family. Structural analysis of the missense variant identified in our study and two previously reported functionally characterized missense changes (p. Glu332Gln and p. His327Arg) in mice showed that all these three variants may affect Mg2+ binding ability and helicase activity of YTHDC2. Collectively, our genetic analyses and experimental observations revealed that missense variant of YTHDC2 can induce azoospermia in humans. These findings indicate the important role of YTHDC2 deficiency for azoospermia and will provide important guidance for genetic counseling of male infertility.

Genetic Risk Loci and Familial Associations in Migraine: A Genome-Wide Association Study in the Han Chinese Population of Taiwan

BACKGROUND AND PURPOSE

Migraine is a condition that is often observed to run in families, but its complex genetic background remains unclear. This study aimed to identify the genetic factors influencing migraines and their potential association with the family medical history.

METHODS

We performed a comprehensive genome-wide association study of a cohort of 1,561 outpatients with migraine and 473 individuals without migraine in Taiwan, including Han Chinese individuals with or without a family history of migraine. By analyzing the detailed headache history of the patients and their relatives we aimed to isolate potential genetic markers associated with migraine while considering factors such as sex, episodic vs. chronic migraine, and the presence of aura.

RESULTS

We revealed novel genetic risk loci, including rs2287637 in DEAD-Box helicase 1 and long intergenic non-protein coding RNA 1804 and rs12055943 in engulfment and cell motility 1, that were correlated with the family history of migraine. We also found a genetic location downstream of mesoderm posterior BHLH transcription factor 2 associated with episodic migraine, whereas loci within the ubiquitin-specific peptidase 26 exonic region, dual specificity phosphatase 9 and pregnancy-upregulated non-ubiquitous CaM kinase intergenic regions, and poly (ADP-ribose) polymerase 1 and STUM were linked to chronic migraine. We additionally identified genetic regionsassociated with the presence or absence of aura. A locus between LINC02561 and urocortin 3 was predominantly observed in female patients. Moreover, three different single-nucleotide polymorphisms were associated with the family history of migraine in the control group.

CONCLUSIONS

This study has identified new genetic locations associated with migraine and its family history in a Han Chinese population, reinforcing the genetic background of migraine. The findings point to potential candidate genes that should be investigated further.

Deleterious variants in X-linked RHOXF1 cause male infertility with oligo- and azoospermia

Oligozoospermia and azoospermia are two common phenotypes of male infertility characterized by massive sperm defects owing to failure of spermatogenesis. The deleterious impact of candidate variants with male infertility is to be explored. In our study, we identified three hemizygous missense variants (c.388G>A: p.V130M, c.272C>T: p.A91V, and c.467C>T: p.A156V) and one hemizygous nonsense variant (c.478C>T: p.R160X) in the Rhox homeobox family member 1 gene (RHOXF1) in four unrelated cases from a cohort of 1201 infertile Chinese men with oligo- and azoospermia using whole-exome sequencing and Sanger sequencing. RHOXF1 was absent in the testicular biopsy of one patient (c.388G>A: p.V130M) whose histological analysis showed a phenotype of Sertoli cell-only syndrome. In vitro experiments indicated that RHOXF1 mutations significantly reduced the content of RHOXF1 protein in HEK293T cells. Specifically, the p.V130M, p.A156V, and p.R160X mutants of RHOXF1 also led to increased RHOXF1 accumulation in cytoplasmic particles. Luciferase assays revealed that p.V130M and p.R160X mutants may disrupt downstream spermatogenesis by perturbing the regulation of doublesex and mab-3 related transcription factor 1 (DMRT1) promoter activity. Furthermore, ICSI treatment could be beneficial in the context of oligozoospermia caused by RHOXF1 mutations. In conclusion, our findings collectively identified mutated RHOXF1 to be a disease-causing X-linked gene in human oligo- and azoospermia.

CCDC146 is required for sperm flagellum biogenesis and male fertility in mice

Multiple morphological abnormalities of the flagella (MMAF) is a severe disease of male infertility, while the pathogenetic mechanisms of MMAF are still incompletely understood. Previously, we found that the deficiency of Ccdc38 might be associated with MMAF. To understand the underlying mechanism of this disease, we identified the potential partner of this protein and found that the coiled-coil domain containing 146 (CCDC146) can interact with CCDC38. It is predominantly expressed in the testes, and the knockout of this gene resulted in complete infertility in male mice but not in females. The knockout of Ccdc146 impaired spermiogenesis, mainly due to flagellum and manchette organization defects, finally led to MMAF-like phenotype. Furthermore, we demonstrated that CCDC146 could interact with both CCDC38 and CCDC42. It also interacts with intraflagellar transport (IFT) complexes IFT88 and IFT20. The knockout of this gene led to the decrease of ODF2, IFT88, and IFT20 protein levels, but did not affect CCDC38, CCDC42, or ODF1 expression. Additionally, we predicted and validated the detailed interactions between CCDC146 and CCDC38 or CCDC42, and built the interaction models at the atomic level. Our results suggest that the testis predominantly expressed gene Ccdc146 is essential for sperm flagellum biogenesis and male fertility, and its mutations might be associated with MMAF in some patients.

Ubiquitin-specific peptidases: Players in bone metabolism

Osteoporosis is an ageing-related disease, that has become a major public health problem and its pathogenesis has not yet been fully elucidated. Substantial evidence suggests a strong link between overall age-related disease progression and epigenetic modifications throughout the life cycle. As an important epigenetic modification, ubiquitination is extensively involved in various physiological processes, and its role in bone metabolism has attracted increasing attention. Ubiquitination can be reversed by deubiquitinases, which counteract protein ubiquitination degradation. As the largest and most structurally diverse cysteinase family of deubiquitinating enzymes, ubiquitin-specific proteases (USPs), comprising the largest and most structurally diverse cysteine kinase family of deubiquitinating enzymes, have been found to be important players in maintaining the balance between bone formation and resorption. The aim of this review is to explore recent findings highlighting the regulatory functions of USPs in bone metabolism and provide insight into the molecular mechanisms governing their actions during bone loss. An in-deep understanding of USPs-mediated regulation of bone formation and bone resorption will provide a scientific rationale for the discovery and development of novel USP-targeted therapeutic strategies for osteoporosis.

Clinical detection, diagnosis and treatment of morphological abnormalities of sperm flagella: A review of literature

Sperm carries male genetic information, and flagella help move the sperm to reach oocytes. When the ultrastructure of the flagella is abnormal, the sperm is unable to reach the oocyte and achieve insemination. Multiple morphological abnormalities of sperm flagella (MMAF) is a relatively rare idiopathic condition that is mainly characterized by multiple defects in sperm flagella. In the last decade, with the development of high-throughput DNA sequencing approaches, many genes have been revealed to be related to MMAF. However, the differences in sperm phenotypes and reproductive outcomes in many cases are attributed to different pathogenic genes or different pathogenic mutations in the same gene. Here, we will review information about the various phenotypes resulting from different pathogenic genes, including sperm ultrastructure and encoding proteins with their location and functions as well as assisted reproductive technology (ART) outcomes. We will share our clinical detection and diagnosis experience to provide additional clinical views and broaden the understanding of this disease.

Successful Results of Intracytoplasmic Sperm Injection of a Chinese Patient With Multiple Morphological Abnormalities of Sperm Flagella Caused by a Novel Splicing Mutation in CFAP251

Asthenospermia is one of the most important causes of male infertility. Among asthenospermia, multiple morphological abnormalities of sperm flagella (MMAF) are relatively rare idiopathic conditions characterized by multiple defects in sperm flagella. Although many studies focusing on the genetic factors of MMAF have been conducted, its pathogenesis and treatment effect remain largely unknown. Here, we report a male patient from a nonconsanguineous Chinese family who exhibited a typical MMAF phenotype revealed by morphological analysis. We identified splicing mutations in CFAP251 (c.1192-3C>G), and the mutation was proven to cause exon skipping. In addition, western blotting and immunofluorescence analysis of the spermatozoa from the proband and a control subject revealed a significantly lower expression of CFAP251 protein due to pathogenic mutation. Interestingly, the patient’s mother was a heterozygous carrier for the mutation, but his father was not, and finally, the inheritance pattern was proven to be maternal uniparental disomy. We applied an intracytoplasmic sperm injection and achieved a successful pregnancy. Above all, our findings expand the spectrum of CFAP251 pathogenic mutations and provide more indications for clinical genetic counseling and assisted reproductive treatment for such patients.

Bi-allelic variants in DNHD1 cause flagellar axoneme defects and asthenoteratozoospermia in humans and mice

Asthenoteratozoospermia, defined as reduced sperm motility and abnormal sperm morphology, is a disorder with considerable genetic heterogeneity. Although previous studies have identified several asthenoteratozoospermia-associated genes, the etiology remains unknown for the majority of affected men. Here, we performed whole-exome sequencing on 497 unrelated men with asthenoteratozoospermia and identified DNHD1 bi-allelic variants from eight families (1.6%). All detected variants were predicted to be deleterious via multiple bioinformatics tools. Hematoxylin and eosin (H&E) staining revealed that individuals with bi-allelic DNHD1 variants presented striking abnormalities of the flagella; transmission electron microscopy (TEM) further showed flagellar axoneme defects, including central pair microtubule (CP) deficiency and mitochondrial sheath (MS) malformations. In sperm from fertile men, DNHD1 was localized to the entire flagella of the normal sperm; however, it was nearly absent in the flagella of men with bi-allelic DNHD1 variants. Moreover, abundance of the CP markers SPAG6 and SPEF2 was significantly reduced in spermatozoa from men harboring bi-allelic DNHD1 variants. In addition, Dnhd1 knockout male mice (Dnhd1^‒/‒) exhibited asthenoteratozoospermia and infertility, a finding consistent with the sperm phenotypes present in human subjects with DNHD1 variants. The female partners of four out of seven men who underwent intracytoplasmic sperm injection therapy subsequently became pregnant. In conclusion, our study showed that bi-allelic DNHD1 variants cause asthenoteratozoospermia, a finding that provides crucial insights into the biological underpinnings of this disorder and should assist with counseling of affected individuals.