RESUMEN

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.

Asunto(s)

Azoospermia , Secuenciación del Exoma , Homocigoto , Mutación Missense , Linaje , Hermanos , Adulto , Animales , Humanos , Masculino , Ratones , Azoospermia/genética , Azoospermia/patología , Consanguinidad , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Pakistán , ARN Helicasas/genética

RESUMEN

Male infertility due to asthenozoospermia is quite frequent, but its etiology is poorly understood. We recruited two infertile brothers, born to first-cousin parents from Pakistan, displaying idiopathic asthenozoospermia with mild stuttering disorder but no ciliary-related symptoms. Whole-exome sequencing identified a splicing variant (c.916+1G>A) in ARMC3, recessively co-segregating with asthenozoospermia in the family. The ARMC3 protein is evolutionarily highly conserved and is mostly expressed in the brain and testicular tissue of human. The ARMC3 splicing mutation leads to the exclusion of exon 8, resulting in a predicted truncated protein (p.Glu245_Asp305delfs*16). Quantitative real-time PCR revealed a significant decrease at mRNA level for ARMC3 and Western blot analysis did not detect ARMC3 protein in the patient's sperm. Individuals homozygous for the ARMC3 splicing variant displayed reduced sperm motility with frequent morphological abnormalities of sperm flagella. Transmission electron microscopy of the affected individual IV: 2 revealed vacuolation in sperm mitochondria at the midpiece and disrupted flagellar ultrastructure in the principal and end piece. Altogether, our results indicate that this novel homozygous ARMC3 splicing mutation destabilizes sperm flagella and leads to asthenozoospermia in our patients, providing a novel marker for genetic counseling and diagnosis of male infertility.

Asunto(s)

Astenozoospermia , Consanguinidad , Homocigoto , Linaje , Empalme del ARN , Cola del Espermatozoide , Adulto , Humanos , Masculino , Astenozoospermia/genética , Astenozoospermia/patología , Secuenciación del Exoma , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Mutación , Empalme del ARN/genética , Motilidad Espermática/genética , Cola del Espermatozoide/patología , Cola del Espermatozoide/ultraestructura , Cola del Espermatozoide/metabolismo , Espermatozoides/ultraestructura , Espermatozoides/patología

RESUMEN

BACKGROUND: Bi-allelic variants in DNAH11 have been identified as causative factors in Primary Ciliary Dyskinesia, leading to abnormal respiratory cilia. Nonetheless, the specific impact of these variants on human sperm flagellar and their involvement in male infertility remain largely unknown. METHODS: A collaborative effort involving two Chinese reproductive centers conducted a study with 975 unrelated infertile men. Whole-exome sequencing was employed for variant screening, and Sanger sequencing confirmed the identified variants. Morphological and ultrastructural analyses of sperm were conducted using Scanning Electron Microscopy and Transmission Electron Microscopy. Western Blot Analysis and Immunofluorescence Analysis were utilized to assess protein levels and localization. ICSI was performed to evaluate its efficacy in achieving favorable pregnancy outcomes for individuals with DNAH11 variants. RESULTS: In this study, we identified seven novel variants in the DNAH11 gene in four asthenoteratozoospermia subjects. These variants led the absence of DNAH11 proteins and ultrastructure defects in sperm flagella, particularly affecting the outer dynein arms (ODAs) and adjacent structures. The levels of ODA protein DNAI2 and axoneme related proteins were down regulated, instead of inner dynein arms (IDA) proteins DNAH1 and DNAH6. Two out of four individuals with DNAH11 variants achieved clinical pregnancies through ICSI. The findings confirm the association between male infertility and bi-allelic deleterious variants in DNAH11, resulting in the aberrant assembly of sperm flagella and contributing to asthenoteratozoospermia. Importantly, ICSI emerges as an effective intervention for overcoming reproductive challenges caused by DNAH11 gene variants.

Asunto(s)

Astenozoospermia , Dineínas Axonemales , Secuenciación del Exoma , Infertilidad Masculina , Humanos , Masculino , Astenozoospermia/genética , Astenozoospermia/patología , Dineínas Axonemales/genética , Femenino , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Adulto , Cola del Espermatozoide/patología , Cola del Espermatozoide/ultraestructura , Cola del Espermatozoide/metabolismo , Inyecciones de Esperma Intracitoplasmáticas , Embarazo , Espermatozoides/ultraestructura , Espermatozoides/patología , Dineínas/genética

RESUMEN

Microtubules, polymers of αß-tubulin heterodimers, are essential for various cellular processes. The incorporation of different tubulin isotypes, each encoded by distinct genes, is proposed to contribute to the functional diversity observed in microtubules. However, the functional roles of each tubulin isotype are not completely understood. In this study, we investigated the role of the ß4B-tubulin isotype (Tubb4b) in spermatogenesis, utilizing a Tubb4b knockout mouse model. We showed that ß4B-tubulin is expressed in the germ cells throughout spermatogenesis. ß4B-tubulin was localized to cytoplasmic microtubules, mitotic spindles, manchette, and axonemes of sperm flagella. We found that the absence of ß4B-tubulin resulted in male infertility and failure to produce sperm cells. Our findings demonstrate that a lack of ß4B-tubulin leads to defects in the initial stages of spermatogenesis. Specifically, ß4B-tubulin is needed for the expansion of differentiating spermatogonia, which is essential for the subsequent progression of spermatogenesis.

Asunto(s)

Diferenciación Celular , Ratones Noqueados , Microtúbulos , Espermatogénesis , Espermatogonias , Tubulina (Proteína) , Animales , Masculino , Tubulina (Proteína)/metabolismo , Tubulina (Proteína)/genética , Espermatogonias/metabolismo , Espermatogonias/citología , Espermatogénesis/genética , Ratones , Microtúbulos/metabolismo , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología

RESUMEN

This study aims to investigate the role of ferroptosis, an iron-dependent form of regulated cell death, in male infertility. The motivation behind this research stems from the increasing recognition of oxidative stress and iron metabolism dysregulation as critical factors in male reproductive health. In this study, 28 infertile patients (grouped by the presence of urogenital infections or varicocele) and 19 fertile men were selected. Spermiograms were performed by light microscopy (WHO, 2021). Testosterone, ferritin, transferrin-bound iron, transferrin, and F2-isoprostanes (F2-IsoPs) were detected in seminal plasma. Glutathione peroxidase 4 (GPX4) and acyl coenzyme A synthetase long chain family member 4 (ACSL4) were also assessed in sperm cells using enzyme-linked immunosorbent assays (ELISA). All the variables were correlated (statistically significant Spearman's rank correlations) in the whole population, and then the comparison between variables of the different groups of men were carried out. Seminal ferritin and transferrin positively correlated with seminal F2-IsoPs, which had positive correlations with ACSL4 detected in sperm cells. Ferritin and ACSL4 negatively correlated with the seminal parameters. No correlation was detected for GPX4. Comparing the variables in the three examined groups, elevated levels of ACSL4 were observed in infertile patients with urogenital infections and varicocele; GPX4 levels were similar in the three groups. These results suggested a mechanism of ferroptosis, identified by increased ACSL4 levels and the occurrence of lipid peroxidation. Such events appear to be GPX4-independent in reproductive pathologies such as varicocele and urogenital infections.

Asunto(s)

Biomarcadores , Ferroptosis , Infertilidad Masculina , Semen , Humanos , Masculino , Semen/metabolismo , Adulto , Biomarcadores/metabolismo , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , Coenzima A Ligasas/metabolismo , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Fertilidad , Espermatozoides/metabolismo , Espermatozoides/patología

RESUMEN

piRNAs are crucial for transposon silencing, germ cell maturation, and fertility in male mice. Here, we report on the genetic landscape of piRNA dysfunction in humans and present 39 infertile men carrying biallelic variants in 14 different piRNA pathway genes, including PIWIL1, GTSF1, GPAT2, MAEL, TDRD1, and DDX4. In some affected men, the testicular phenotypes differ from those of the respective knockout mice and range from complete germ cell loss to the production of a few morphologically abnormal sperm. A reduced number of pachytene piRNAs was detected in the testicular tissue of variant carriers, demonstrating impaired piRNA biogenesis. Furthermore, LINE1 expression in spermatogonia links impaired piRNA biogenesis to transposon de-silencing and serves to classify variants as functionally relevant. These results establish the disrupted piRNA pathway as a major cause of human spermatogenic failure and provide insights into transposon silencing in human male germ cells.

Asunto(s)

Elementos Transponibles de ADN , Infertilidad Masculina , ARN Interferente Pequeño , Espermatogénesis , Testículo , Masculino , Humanos , Espermatogénesis/genética , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , ARN Interferente Pequeño/metabolismo , ARN Interferente Pequeño/genética , Elementos Transponibles de ADN/genética , Animales , Testículo/metabolismo , Ratones , Adulto , Silenciador del Gen , Ratones Noqueados , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Elementos de Nucleótido Esparcido Largo/genética , Espermatogonias/metabolismo , ARN Helicasas DEAD-box/genética , ARN Helicasas DEAD-box/metabolismo , ARN de Interacción con Piwi

RESUMEN

Ciliary beat and intraflagellar transport depend on dynein and kinesin motors. The kinesin-9 family members Kif6 and Kif9 are implicated in motile cilia motilities across protists and mammals. How they function and whether they act redundantly, however, remain unclear. Here, we show that Kif6 and Kif9 play distinct roles in mammals. Kif6 forms puncta that move bidirectionally along axonemes, whereas Kif9 appears to oscillate regionally on the ciliary central apparatus. Consistently, only Kif6 displays microtubule-based motor activity in vitro, and its ciliary localization requires its ATPase activity. Kif6 deficiency in mice disrupts coordinated ciliary beat across ependymal tissues and impairs cerebrospinal fluid flow, resulting in severe hydrocephalus and high mortality. Kif9 deficiency causes mild hydrocephalus without obviously affecting the ciliary beat or the lifespan. Kif6-/- and Kif9-/- males are infertile but exhibit oligozoospermia with poor sperm motility and defective forward motion of sperms, respectively. These results suggest Kif6 as a motor for cargo transport and Kif9 as a central apparatus regulator.

Asunto(s)

Cilios , Cinesinas , Ratones Noqueados , Animales , Cinesinas/metabolismo , Cinesinas/genética , Cilios/metabolismo , Masculino , Ratones , Transporte de Proteínas , Motilidad Espermática/genética , Hidrocefalia/metabolismo , Hidrocefalia/genética , Hidrocefalia/patología , Ratones Endogámicos C57BL , Axonema/metabolismo , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , Humanos , Microtúbulos/metabolismo

RESUMEN

The Vps13a gene encodes a lipid transfer protein called VPS13A, or chorein, associated with mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs), mitochondria-endosomes, and lipid droplets. This protein plays a crucial role in inter-organelle communication and lipid transport. Mutations in the VPS13A gene are implicated in the pathogenesis of chorea-acanthocytosis (ChAc), a rare autosomal recessive neurodegenerative disorder characterized by chorea, orofacial dyskinesias, hyperkinetic movements, seizures, cognitive impairment, and acanthocytosis. Previous mouse models of ChAc have shown variable disease phenotypes depending on the genetic background. In this study, we report the generation of a Vps13a flox allele in a pure C57BL/6N mouse background and the subsequent creation of Vps13a knockout (KO) mice via Cre-recombination. Our Vps13a KO mice exhibited increased reticulocytes but not acanthocytes in peripheral blood smears. Additionally, there were no significant differences in the GFAP- and Iba1-positive cells in the striatum, the basal ganglia of the central nervous system. Interestingly, we observed abnormal spermatogenesis leading to male infertility. These findings indicate that Vps13a KO mice are valuable models for studying male infertility and some hematological aspects of ChAc.

Asunto(s)

Encéfalo , Ratones Endogámicos C57BL , Ratones Noqueados , Neuroacantocitosis , Fenotipo , Testículo , Proteínas de Transporte Vesicular , Animales , Masculino , Proteínas de Transporte Vesicular/genética , Ratones , Testículo/metabolismo , Testículo/patología , Encéfalo/metabolismo , Encéfalo/patología , Neuroacantocitosis/genética , Neuroacantocitosis/patología , Modelos Animales de Enfermedad , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Espermatogénesis/genética

RESUMEN

PURPOSE: To identify novel variants in ACTL9 and new phenotypes responsible for male infertility. METHODS: Genomic DNA was extracted from peripheral blood samples for whole-exome sequencing (WES). Computer-assisted sperm analysis (CASA) was used to test the motility of spermatozoa. The ultrastructure of flagella and the mitochondrial sheath were assessed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Immunostaining was used to validate the localization and expression of ACTL9 and ACTL7A. An Actl9-mutated mouse model was used to validate the phenotypes by CASA and TEM. RESULTS: We identified novel homozygous variants in ACTL9 in two independent Chinese families. Spermatozoa with ACTL9 mutations showed decreased CASA parameters and a higher proportion of spermatozoa with abnormal morphology, exhibiting coiled flagella and a thickened midpiece. The spermatozoa were characterized by chaotic or irregular '9+2' structures and irregular mitochondrial sheath arrangements in the flagellum. Actl9 knock-in mice also showed abnormal CASA parameters and irregular '9+2' structures in flagella. CONCLUSIONS: Our study expands the mutation spectrum and phenotypic spectrum of ACTL9.

Asunto(s)

Flagelos , Homocigoto , Infertilidad Masculina , Mitocondrias , Mutación , Motilidad Espermática , Cola del Espermatozoide , Espermatozoides , Masculino , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Humanos , Ratones , Espermatozoides/patología , Espermatozoides/ultraestructura , Espermatozoides/metabolismo , Animales , Mitocondrias/genética , Mitocondrias/ultraestructura , Mitocondrias/patología , Mitocondrias/metabolismo , Mutación/genética , Cola del Espermatozoide/patología , Cola del Espermatozoide/metabolismo , Cola del Espermatozoide/ultraestructura , Flagelos/genética , Flagelos/ultraestructura , Flagelos/metabolismo , Motilidad Espermática/genética , Secuenciación del Exoma , Linaje , Adulto , Análisis de Semen

RESUMEN

PURPOSE: To investigate whether the DNA methylation profiles of GNAS(20q13.32), MEST(7q32.2), MESTIT1(7q32.2), IGF2(11p15.5), H19 (7q32.2), and CEP41(7q32.2) genes are related to the transcriptomic and epigenomic etiology of male infertility. METHODS: The DNA methylation levels of spermatozoa were obtained from fertile (n = 30), oligozoospermic (n = 30), and men with normal sperm count (n = 30). The methylation status of each CpG site was categorized as hypermethylated or hypomethylated. Expression levels of target gene transcripts were determined using real-time PCR. RESULTS: The oligozoospermia showed a higher frequency of hypermethylation at GNASAS 1st, 3rd, and 5th CpG dinucleotides (66.7%, 73.3%, 73.3%) compared to the fertile group (33.3%, 33.3%, 40%, respectively). The normal sperm count exhibited a higher frequency of hypermethylation at the 3rd CpG of CEP41 (46.7%) than the fertile group (16.7%). Normal sperm count was predicted by CEP41 hypermethylation (OR = 1.750, 95%CI 1.038-2.950) and hypermethylation of both CEP41 and GNASAS (OR = 2.389, 95%CI 1.137-5.021). Oligozoospermia was predicted solely by GNASAS hypermethylation (OR = 2.460, 95%CI 1.315-4.603). In sperms with decreased IGF2 expression in the fertile group, we observed hypomethylation in the 2nd CpG of IGF2 antisense (IFG2AS), and hypermethylation in the 1st, 2nd, and 4th CpGs of H19. No significant relationship was found between IGF2 expression and methylation status of IGF2AS and H19 in infertile groups. CONCLUSION: The disappearance of the relationship between IGF2 expression and IGF2AS and H19 methylations in the infertile group provides new information regarding the disruption of epigenetic programming during spermatogenesis. A better understanding of sperm GNASAS and CEP41 hypermethylation could advance innovative diagnostic markers for male infertility.

Asunto(s)

Cromograninas , Metilación de ADN , Subunidades alfa de la Proteína de Unión al GTP Gs , Impresión Genómica , Infertilidad Masculina , Oligospermia , Masculino , Humanos , Metilación de ADN/genética , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Cromograninas/genética , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Impresión Genómica/genética , Adulto , Oligospermia/genética , Oligospermia/patología , Espermatozoides/patología , Espermatozoides/metabolismo , Factor II del Crecimiento Similar a la Insulina/genética , Epigénesis Genética/genética , Islas de CpG/genética , ARN Largo no Codificante/genética , Recuento de Espermatozoides

RESUMEN

Inner dynein arms (IDAs) are formed from a protein complex that is essential for appropriate flagellar bending and beating. IDA defects have previously been linked to the incidence of asthenozoospermia (AZS) and male infertility. The testes-enriched ZMYND12 protein is homologous with an IDA component identified in Chlamydomonas. ZMYND12 deficiency has previously been tied to infertility in males, yet the underlying mechanism remains uncertain. Here, a CRISPR/Cas9 approach was employed to generate Zmynd12 knockout (Zmynd12-/-) mice. These Zmynd12-/- mice exhibited significant male subfertility, reduced sperm motile velocity, and impaired capacitation. Through a combination of co-immunoprecipitation and mass spectrometry, ZMYND12 was found to interact with TTC29 and PRKACA. Decreases in the levels of PRKACA were evident in the sperm of these Zmynd12-/- mice, suggesting that this change may account for the observed drop in male fertility. Moreover, in a cohort of patients with AZS, one patient carrying a ZMYND12 variant was identified, expanding the known AZS-related variant spectrum. Together, these findings demonstrate that ZMYND12 is essential for flagellar beating, capacitation, and male fertility.

Asunto(s)

Infertilidad Masculina , Ratones Noqueados , Motilidad Espermática , Animales , Humanos , Masculino , Ratones , Astenozoospermia/genética , Astenozoospermia/metabolismo , Astenozoospermia/patología , Sistemas CRISPR-Cas , Dineínas/metabolismo , Dineínas/genética , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , Ratones Endogámicos C57BL , Capacitación Espermática/genética , Motilidad Espermática/genética , Espermatozoides/metabolismo , Contactina 2/genética , Contactina 2/metabolismo

RESUMEN

Male infertility arises from a complex interplay of factors affecting reproductive organs and various physiological pathways. Among these, erectile dysfunction (ED), a widespread global issue, plays a key role. While existing ED treatments address some aspects, achieving complete reversibility and avoiding side effects remains a challenge. In this context, stem cell therapy emerges as a promising, potentially transformative approach. Preliminary evidence from preclinical animal models and clinical trials highlights stem cell therapy's remarkable efficacy and effectiveness for ED. This novel strategy offers several advantages, including enhanced effectiveness and a reported absence of adverse side effects. This review delves into the causes of male infertility, with a particular focus on ED and its pathophysiology. We explore the current treatment landscape, highlighting therapy's existing strategies' limitations and stem cell therapy's unique potential. By examining relevant preclinical and clinical studies, we provide a comprehensive picture of this innovative approach and its promising future in restoring men's fertility and quality of life.

Asunto(s)

Disfunción Eréctil , Infertilidad Masculina , Trasplante de Células Madre , Humanos , Masculino , Disfunción Eréctil/terapia , Trasplante de Células Madre/métodos , Animales , Infertilidad Masculina/terapia , Infertilidad Masculina/patología , Calidad de Vida , Células Madre

RESUMEN

TTC12 is a cytoplasmic and centromere-localized protein that plays a role in the proper assembly of dynein arm complexes in motile cilia in both respiratory cells and sperm flagella. This finding underscores its significance in cellular motility and function. However, the wide role of TTC12 in human spermatogenesis-associated primary ciliary dyskinesia (PCD) still needs to be elucidated. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify potentially pathogenic variants causing PCD and multiple morphological abnormalities of sperm flagella (MMAF) in an infertile Pakistani man. Diagnostic imaging techniques were used for PCD screening in the patient. Real-time polymerase chain reaction (RT‒PCR) was performed to detect the effect of mutations on the mRNA abundance of the affected genes. Papanicolaou staining and scanning electron microscopy (SEM) were carried out to examine sperm morphology. Transmission electron microscopy (TEM) was performed to examine the ultrastructure of the sperm flagella, and the results were confirmed by immunofluorescence staining. Using WES and Sanger sequencing, a novel homozygous missense variant (c.C1069T; p.Arg357Trp) in TTC12 was identified in a patient from a consanguineous family. A computed tomography scan of the paranasal sinuses confirmed the symptoms of the PCD. RT-PCR showed a decrease in TTC12 mRNA in the patient's sperm sample. Papanicolaou staining, SEM, and TEM analysis revealed a significant change in shape and a disorganized axonemal structure in the sperm flagella of the patient. Immunostaining assays revealed that TTC12 is distributed throughout the flagella and is predominantly concentrated in the midpiece in normal spermatozoa. In contrast, spermatozoa from patient deficient in TTC12 showed minimal staining intensity for TTC12 or DNAH17 (outer dynein arms components). This could lead to MMAF and result in male infertility. This novel TTC12 variant not only illuminates the underlying genetic causes of male infertility but also paves the way for potential treatments targeting these genetic factors. This study represents a significant advancement in understanding the genetic basis of PCD-related infertility.

Asunto(s)

Homocigoto , Infertilidad Masculina , Mutación Missense , Cola del Espermatozoide , Humanos , Masculino , Mutación Missense/genética , Pakistán , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Cola del Espermatozoide/patología , Cola del Espermatozoide/ultraestructura , Cola del Espermatozoide/metabolismo , Adulto , Linaje , Astenozoospermia/genética , Astenozoospermia/patología , Trastornos de la Motilidad Ciliar/genética , Trastornos de la Motilidad Ciliar/patología , Secuenciación del Exoma , Oligospermia/genética , Oligospermia/patología , Síndrome de Kartagener/genética , Síndrome de Kartagener/patología

RESUMEN

Spermatogenesis is a multi-step biological process where mitotically active diploid (2n) spermatogonia differentiate into haploid (n) spermatozoa via regulated meiotic programming. The alarming rise in male infertility has become a global concern during the past decade thereby demanding an extensive profiling of testicular gene expression. Advancements in Next-Generation Sequencing (NGS) technologies have revolutionized our empathy towards complex biological events including spermatogenesis. However, despite multiple attempts made in the past to reveal the testicular transcriptional signature(s) either with bulk tissues or at the single-cell, level, comprehensive reviews on testicular transcriptomics and associated disorders are limited. Notably, technologies explicating the genome-wide gene expression patterns during various stages of spermatogenic progression provide the dynamic molecular landscape of testicular transcription. Our review discusses the advantages of single-cell RNA-sequencing (Sc-RNA-seq) over bulk RNA-seq concerning testicular tissues. Additionally, we highlight the cellular heterogeneity, spatial transcriptomics, dynamic gene expression and cell-to-cell interactions with distinct cell populations within the testes including germ cells (Gc), Sertoli cells (Sc), Peritubular cells (PTc), Leydig cells (Lc), etc. Furthermore, we provide a summary of key finding of single-cell transcriptomic studies that have shed light on developmental mechanisms implicated in testicular disorders and male infertility. These insights emphasize the pivotal roles of Sc-RNA-seq in advancing our knowledge regarding testicular transcriptional landscape and may serve as a potential resource to formulate future clinical interventions for male reproductive health.

Asunto(s)

Infertilidad Masculina , Análisis de la Célula Individual , Testículo , Transcriptoma , Masculino , Humanos , Testículo/metabolismo , Testículo/patología , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Infertilidad Masculina/metabolismo , Animales , Espermatogénesis/genética , Perfilación de la Expresión Génica

RESUMEN

Dynein complexes are large, multi-unit assemblies involved in many biological processes via their critical roles in protein transport and axoneme motility. Using next-generation sequencing of infertile men presenting with low or no sperm in their ejaculates, we identified damaging variants in the dynein-related gene AXDND1. We thus hypothesised that AXDND1 is a critical regulator of male fertility. To test this hypothesis, we produced a knockout mouse model. Axdnd1-/- males were sterile at all ages but presented with an evolving testis phenotype wherein they could undergo one round of histologically replete spermatogenesis followed by a rapid depletion of the seminiferous epithelium. Marker experiments identified a role for AXDND1 in maintaining the balance between differentiation-committed and self-renewing spermatogonial populations, resulting in disproportionate production of differentiating cells in the absence of AXDND1 and increased sperm production during initial spermatogenic waves. Moreover, long-term spermatogonial maintenance in the Axdnd1 knockout was compromised, ultimately leading to catastrophic germ cell loss, destruction of blood-testis barrier integrity and immune cell infiltration. In addition, sperm produced during the first wave of spermatogenesis were immotile due to abnormal axoneme structure, including the presence of ectopic vesicles and abnormalities in outer dense fibres and microtubule doublet structures. Sperm output was additionally compromised by a severe spermiation defect and abnormal sperm individualisation. Collectively these data identify AXDND1 as an atypical dynein complex-related protein with a role in protein/vesicle transport of relevance to spermatogonial function and sperm tail formation in mice and humans. This study underscores the importance of studying the consequences of gene loss-of-function on both the establishment and maintenance of male fertility.

Asunto(s)

Ratones Noqueados , Cola del Espermatozoide , Espermatogénesis , Espermatogonias , Animales , Humanos , Masculino , Ratones , Diferenciación Celular , Dineínas/metabolismo , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , Ratones Endogámicos C57BL , Cola del Espermatozoide/metabolismo , Espermatogénesis/genética , Espermatogonias/metabolismo , Testículo/metabolismo , Dineínas Axonemales/genética , Dineínas Axonemales/metabolismo

RESUMEN

OBJECTIVES: To investigate the distribution of sperm DNA fragmentation (SDF) values and their association with clinical and seminal parameters in idiopathic infertile men. DESIGN, PATIENTS, MEASUREMENTS: Data from 3224 primary infertile men (belonging to couples having failed to conceive a pregnancy within 12 months) who underwent a thorough diagnostic work-up were analysed. A SDF value ≥ 30% (according to Sperm Chromatin Structure Assay) was considered pathologic. We excluded: (1) men with genetic abnormalities; (2) men with history of cryptorchidism; (3) men with biochemical hypogonadism; (4) men with clinical varicocele; and (5) men with other possible known aetiological factors. Descriptive statistics and logistic regression analyses were used to describe the whole cohort. RESULTS: Of all, 792 (23%) men with at least one abnormal WHO semen parameter but without any identified aetiologic factor for infertility, were considered as idiopathic infertile men. Of 792, 418 (52.7%) men had SDF ≥30%. Men with pathologic SDF were older (p = .02), had higher Follicle-stimulating hormone (FSH) (p = .04) but lower total testosterone (p = .03) values than those with SDF <30%. The homoeostatic model assessment index for insulin resistance (HOMA-IR) was higher in men with SDF ≥30% (p = .01). Idiopathic infertile men with SDF ≥30% presented with lower sperm concentration (p < .001) and lower progressive sperm motility (p < .01) than those with SDF < 30%. Logistic regression analysis revealed that older age (OR: 1.1, p = .02) and higher HOMA-IR score (OR: 1.8, p = .03) were associated with SDF ≥ 30%, after accounting for FSH and sperm concentration values. CONCLUSIONS: Approximately half of infertile men categorized as idiopathic had pathologic SDF values. Idiopathic infertile men with pathologic SDF showed worse clinical, hormonal and semen parameters than those with normal SDF values. These results suggest that including SDF testing could be clinically relevant over the real-life management work-up of infertile men.

Asunto(s)

Fragmentación del ADN , Hormona Folículo Estimulante , Infertilidad Masculina , Espermatozoides , Humanos , Masculino , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Adulto , Espermatozoides/patología , Espermatozoides/metabolismo , Hormona Folículo Estimulante/sangre , Testosterona/sangre , Análisis de Semen , Persona de Mediana Edad , Resistencia a la Insulina

RESUMEN

Spermatogenesis requires precise posttranslational control in the endoplasmic reticulum (ER), but the mechanism remains largely unknown. The protein disulfide isomerase (PDI) family is a group of thiol oxidoreductases responsible for catalyzing the disulfide bond formation of nascent proteins. In this study, we generated 14 strains of KO mice lacking the PDI family enzymes and found that only PDI deficiency caused spermatogenesis defects. Both inducible whole-body PDI-KO (UBC-Cre/Pdifl/fl) mice and premeiotic PDI-KO (Stra8-Cre/Pdifl/fl) mice experienced a significant decrease in germ cells, testicular atrophy, oligospermia, and complete male infertility. Stra8-Cre/Pdifl/fl spermatocytes had significantly upregulated ER stress-related proteins (GRP78 and XBP1) and apoptosis-related proteins (Cleaved caspase-3 and BAX), together with cell apoptosis. PDI deletion led to delayed DNA double-strand break repair and improper crossover at the pachytene spermatocytes. Quantitative mass spectrometry indicated that PDI deficiency downregulated vital proteins in spermatogenesis such as HSPA4L, SHCBP1L, and DDX4, consistent with the proteins' physical association with PDI in normal testes tissue. Furthermore, PDI served as a thiol oxidase for disulfide bond formation of SHCBP1L. Thus, PDI plays an essential role in protein quality control for spermatogenesis in mice.

Asunto(s)

Chaperón BiP del Retículo Endoplásmico , Ratones Noqueados , Proteína Disulfuro Isomerasas , Espermatogénesis , Testículo , Animales , Masculino , Espermatogénesis/genética , Proteína Disulfuro Isomerasas/metabolismo , Proteína Disulfuro Isomerasas/genética , Ratones , Testículo/metabolismo , Chaperón BiP del Retículo Endoplásmico/metabolismo , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Infertilidad Masculina/patología , Apoptosis , Espermatocitos/metabolismo , Estrés del Retículo Endoplásmico , Oligospermia/genética , Oligospermia/metabolismo , Oligospermia/patología

RESUMEN

Odad3 gene loss-of-function mutation leads to Primary Ciliary Dyskinesia (PCD), a disease caused by motile cilia dysfunction. Previously, we demonstrated that knockout of the Odad3 gene in mice replicates several features of PCD, such as hydrocephalus, defects in left-right body symmetry, and male infertility, with a complete absence of sperm in the reproductive tract. The majority of Odad3 knockout animals die before sexual maturation due to severe hydrocephalus and failure to thrive, which precludes fertility studies. Here, we performed the expression analysis of the Odad3 gene during gonad development and in adult testes. We showed that Odad3 starts its expression during the first wave of spermatogenesis, specifically at the meiotic stage, and that its expression is restricted to the germ cells in the adult testes, suggesting that Odad3 plays a role in spermatozoa formation. Subsequently, we conditionally deleted the Odad3 gene in adult males and demonstrated that even partial ablation of the Odad3 gene leads to asthenoteratozoospermia with multiple morphological abnormalities of sperm flagella (MMAF) in mice. The analysis of the seminiferous tubules in Odad3-deficient mice revealed defects in spermatogenesis with accumulation of seminiferous tubules at the spermiogenesis and spermiation phases. Furthermore, analysis of fertility in heterozygous Odad3+/- knockout mice revealed a reduction in sperm count and motility as well as abnormal sperm morphology. Additionally, Odad3+/- males exhibited a shorter fertile lifespan. Overall, these results suggest the important role of Odad3 and Odad3 gene dosage in male fertility. These findings may have an impact on the genetic and fertility counseling practice of PCD patients carrying Odad3 loss-of-function mutations.

Asunto(s)

Fertilidad , Ratones Noqueados , Espermatogénesis , Espermatozoides , Animales , Masculino , Espermatogénesis/genética , Fertilidad/genética , Ratones , Espermatozoides/metabolismo , Testículo/metabolismo , Testículo/patología , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Ratones Endogámicos C57BL

RESUMEN

BACKGROUND: The prevalence of infertility among couples is estimated to range from 8 to 12%. A paradigm shift has occurred in understanding of infertility, challenging the notion that it predominantly affects women. It is now acknowledged that a significant proportion, if not the majority, of infertility cases can be attributed to male-related factors. Various elements contribute to male reproductive impairments, including aberrant sperm production caused by pituitary malfunction, testicular malignancies, aplastic germ cells, varicocele, and environmental factors. MAIN BODY: The epigenetic profile of mammalian sperm is distinctive and specialized. Various epigenetic factors regulate genes across different levels in sperm, thereby affecting its function. Changes in sperm epigenetics, potentially influenced by factors such as environmental exposures, could contribute to the development of male infertility. CONCLUSION: In conclusion, this review investigates the latest studies pertaining to the mechanisms of epigenetic changes that occur in sperm cells and their association with male reproductive issues.

Asunto(s)

Metilación de ADN , Epigénesis Genética , Infertilidad Masculina , Espermatozoides , Humanos , Masculino , Epigénesis Genética/genética , Infertilidad Masculina/genética , Infertilidad Masculina/patología , Espermatozoides/metabolismo , Espermatozoides/patología , Metilación de ADN/genética , Animales

RESUMEN

PURPOSE: To investigate the occurrence of idiopathic secondary azoospermia (ISA) in men with oligospermia over time and identify risk factors for ISA in this population. METHODS: This was a retrospective cohort study conducted in a university-affiliated male infertility clinic. A total of 1056 oligospermic men (concentration < 15 million/ml (M/ml) and no azoospermia) with at least two SA done between 2000 and 2019 were included. The primary outcome was the occurrence of ISA by oligospermia severity. RESULTS: In the entire cohort, 31 patients (2.9%) eventually became azoospermic with time. The ≤ 1 M/ml extremely severe oligospermia (ESO) group (283 patients) had significantly higher rates of ISA in each time period compared to the 1-5 M/ml severe oligospermia (SO) (310 patients) and 5-15 M/ml mild oligospermia (MO) (463 patients) groups (p < 0.05 for all comparisons), with rates of 21.1% in the ESO, 4.8% in the SO, and 0% in the MO group (p = 0.02) after 3-5 years, reaching 32% after 5 years in the ESO group compared to no cases in the other two groups (p = 0.006). Parameters shown to predict ISA were initial concentration < 1 M/ml (OR 22.12, p < 0.001) and time interval of > 3 and 5 years (OR 4.83 and 6.84, p = 0.009 and < 0.001, respectively), whereas testosterone levels were negatively associated with ISA (OR 0.88, p = 0.03). CONCLUSIONS: Men with ≤ 1 M/ml, especially those with low testosterone levels, have a dramatically increased chance of becoming azoospermic with time. Therefore, sperm banking should be recommended in these cases. Men with a sperm concentration above 1 M/ml have low chances of becoming azoospermic, even after 3 or more years.

Asunto(s)

Azoospermia , Oligospermia , Humanos , Masculino , Oligospermia/patología , Oligospermia/epidemiología , Azoospermia/patología , Azoospermia/epidemiología , Adulto , Estudios Retrospectivos , Recuento de Espermatozoides , Infertilidad Masculina/patología , Infertilidad Masculina/epidemiología , Factores de Riesgo , Análisis de Semen , Testosterona/sangre