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WIREs Mechanisms of Disease Sep 2022Mammalian sperm, the only cells that achieve their purpose outside their organism of origin, have to swim vigorously within the female reproductive tract to reach an...
Mammalian sperm, the only cells that achieve their purpose outside their organism of origin, have to swim vigorously within the female reproductive tract to reach an oocyte. Flagellar dyneins drive sperm motility, which accounts for the consumption of high amounts of ATP. The two main ATP-producing metabolic pathways are compartmentalized in sperm: oxidative phosphorylation in the midpiece and glycolysis in the principal piece. The relative preponderance of these pathways has been discussed for decades (the so-called sperm energy debate). The debate has been muddled by species-specific variances and by technical constraints. But recent findings suggest that sperm from most mammalian species employ a versatile metabolic strategy to maintain motility according to the physiological environment. Different metabolic pathways likely coordinate by using exogenous and/or endogenous substrates in order to produce ATP efficiently. Defects in any of these pathways (glycolysis, mitochondrial oxidative phosphorylation, Krebs cycle, fatty acids oxidation, and ketone bodies oxidation, among others) may disturb sperm motility and be at the origin of male infertility. Understanding sperm bioenergetics is thus crucial for building new diagnostic tools, and for the development of treatments for patients presenting with low sperm motility. Some of these patients may benefit from personalized metabolic supplementations and dietary interventions. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology.
Topics: Adenosine Triphosphate; Animals; Energy Metabolism; Female; Male; Mammals; Oxidative Phosphorylation; Semen; Sperm Motility
PubMed: 35680646
DOI: 10.1002/wsbm.1569 -
International Journal of Molecular... Jan 2023Swim-up selected human sperm were incubated with 7 ng F-neuroprostanes (F-NeuroPs) for 2 and 4 h. Sperm motility and membrane mitochondrial potential (MMP) were...
Swim-up selected human sperm were incubated with 7 ng F-neuroprostanes (F-NeuroPs) for 2 and 4 h. Sperm motility and membrane mitochondrial potential (MMP) were evaluated. The percentage of reacted acrosome was assessed by pisum sativum agglutinin (PSA). Chromatin integrity was detected using the acridine orange (AO) assay and localization of the ryanodine receptor was performed by immunofluorescence analysis. Sperm progressive motility ( = 0.02) and the percentage of sperm showing a strong MMP signal ( = 0.012) significantly increased after 2 h F-NeuroP incubation compared to control samples. The AO assay did not show differences in the percentage of sperm with dsDNA between treated or control samples. Meanwhile, a significantly higher number of sperm with reacted acrosomes was highlighted by PSA localization after 4 h F-NeuroP incubation. Finally, using an anti-ryanodine antibody, the immunofluorescence signal was differentially distributed at 2 and 4 h: a strong signal was evident in the midpiece and postacrosomal sheath (70% of sperm) at 2 h, whereas a dotted one appeared at 4 h (53% of sperm). A defined concentration of F-NeuroPs in seminal fluid may induce sperm capacitation via channel ions present in sperm cells, representing an aid during in vitro sperm preparation that may increase the positive outcome of assisted fertilization.
Topics: Humans; Male; Neuroprostanes; Sperm Motility; Seeds; Spermatozoa; Acrosome; Acridine Orange
PubMed: 36674450
DOI: 10.3390/ijms24020935 -
JBRA Assisted Reproduction Jul 2021Lyophilization is potentially more practical and cost-effective alternative for sperm preservation. However, there are no studies that evaluate the ultrastructure of...
OBJECTIVE
Lyophilization is potentially more practical and cost-effective alternative for sperm preservation. However, there are no studies that evaluate the ultrastructure of human spermatozoa after lyophilization. Therefore, the aim of our study was to evaluate the ultrasctructure of lyophilized spermatozoa using Transmission Electron Microscopy.
METHODS
From a total of 21 donated seminal samples, 30 aliquots were originated and divided into two aliquots so that one could have been submitted to cryopreservation/thaw and the other for lyophilization/rehydration. The liquefied aliquots were homogenized at room temperature. Samples assigned for cryopreservation were placed in straws and samples assigned for lyophilization were placed in the appropriate vials. Cryopreservation samples were placed at -30oC for 30 minutes subsequently for 30 minutes at vapour phase and then plunged into liquid nitrogen. Lately, were warmed in water bath at 37oC for 10 minutes followed by 10 minutes centrifugation. The pellet was resuspended and analysed in a Makler chamber. The semen vials assigned for lyophilization were loaded into a pre-fixed freeze-drying chamber. Following lyophilization, vials were removed from the freeze-drying chamber and kept at 4oC until rehydration. TEM was performed after rehydration and thawing. Sperm samples were fixed, rinsed in buffer, post fixed and dehydration was carried out in escalating concentrations of alcohol solution, acetone and then, embedding in Epon resin. Ultrathin sections were stained and examined in a Transmission Electron Microscope.
RESULTS
Analysis of sperm after freezing/thawing using Transmission Electron Microscopy showed lesions to the midpiece, with some mitochondria degeneration and random rupture of plasma membrane. In the head, we identified intact plasma membrane, nucleus and acrosome, as in the flagellum all main structures remained intact including the plasma membrane, the longitudinal columns of dense fibers and the semicircular fibers. Analysis by Transmission Electron Microscopy showed that spermatozoa heads had ruptured plasma membranes, absence of acrosomes, nuclei with heterogeneous and decompressed chromatin. Mitochondria were deteriorated in the midpiece. Longitudinal columns of dense fibers were absent in the flagellum. Axonemes, in cross-sections, were disrupted with disorganized structures.
CONCLUSIONS
To our knowledge, our study demonstrated, for the first time, the structure of the human spermatozoa after lyophilization using Transmission Electron Microscopy. The use of a fixed lyophilization protocol with media containing cryoprotectants might explain the damage to the structures. More studies are necessary to improve the results of sperm lyophilization. In the future, the use of lyophilization of spermatozoa might reduce the costs of fertility preservation, since there will be no need for storage space and transportation is simpler.
Topics: Acrosome; Cryopreservation; Humans; Male; Semen; Semen Preservation; Sperm Motility; Spermatozoa
PubMed: 34286941
DOI: 10.5935/1518-0557.20210028 -
International Journal of Molecular... Jul 2022The sperm flagellum is essential for male fertility. Multiple morphological abnormalities of the sperm flagella (MMAF) is a severe form of asthenoteratozoospermia. MMAF...
The sperm flagellum is essential for male fertility. Multiple morphological abnormalities of the sperm flagella (MMAF) is a severe form of asthenoteratozoospermia. MMAF phenotypes are understood to result from pathogenic variants of genes from multiple families including AKAP, DANI, DNAH, RSPH, CCDC, CFAP, TTC, and LRRC, among others. The Leucine-rich repeat protein (LRRC) family includes two members reported to cause MMAF phenotypes: and . Despite vigorous research towards understanding the pathogenesis of MMAF-related diseases, many genes remain unknown underlying the flagellum biogenesis. Here, we found that Leucine-rich repeat containing 46 (LRRC46) is specifically expressed in the testes of adult mice, and show that LRRC46 is essential for sperm flagellum biogenesis. Both scanning electron microscopy (SEM) and Papanicolaou staining (PS) presents that the knockout of in mice resulted in typical MMAF phenotypes, including sperm with short, coiled, and irregular flagella. The male KO mice had reduced total sperm counts, impaired sperm motility, and were completely infertile. No reproductive phenotypes were detected in female mice. Immunofluorescence (IF) assays showed that LRRC46 was present throughout the entire flagella of control sperm, albeit with evident concentration at the mid-piece. Transmission electron microscopy (TEM) demonstrated striking flagellar defects with axonemal and mitochondrial sheath malformations. About the important part of the Materials and Methods, SEM and PS were used to observe the typical MMAF-related irregular flagella morphological phenotypes, TEM was used to further inspect the sperm flagellum defects in ultrastructure, and IF was chosen to confirm the location of protein. Our study suggests that LRRC46 is an essential protein for sperm flagellum biogenesis, and its mutations might be associated with MMAF that causes male infertility. Thus, our study provides insights for understanding developmental processes underlying sperm flagellum formation and contribute to further observe the pathogenic genes that cause male infertility.
Topics: Abnormalities, Multiple; Animals; Female; Fertility; Flagella; Humans; Infertility, Male; Male; Mice; Mutation; Proteins; Semen; Sperm Motility; Sperm Tail; Spermatogenesis; Spermatozoa; Exome Sequencing
PubMed: 35955660
DOI: 10.3390/ijms23158525 -
Journal of Medical Genetics Feb 2023Asthenozoospermia is a major factor contributing to male infertility. The mitochondrial sheath (MS), an important organelle in the midpiece of spermatozoa, is crucial to...
BACKGROUND
Asthenozoospermia is a major factor contributing to male infertility. The mitochondrial sheath (MS), an important organelle in the midpiece of spermatozoa, is crucial to sperm motility. ARMC12 is a mitochondrial peripheral membrane protein. Deletion of impairs the arrangement of MS and causes infertility in mice. However, the role of in human asthenozoospermia remains unknown.
OBJECTIVE
To study the genetic defects in patients with asthenozoospermia.
METHODS
A total of 125 patients with asthenozoospermia and 120 men with proven fertility were recruited. Whole-exome sequencing and Sanger sequencing were performed for genetic analysis. Papanicolaou staining, HE staining, immunofluorescent staining, transmission electron microscopy and field emission scanning electron microscopy were employed to observe the morphological and structural defects of the spermatozoa and testes. -knockout mice were generated using the CRISPR-Cas9 system. Intracytoplasmic sperm injection was used to treat the patients.
RESULTS
Biallelic mutations were identified in three patients, including homozygous mutations in two siblings from a consanguineous family and compound heterozygous mutations in one sporadic patient. ARMC12 is mainly expressed in the midpiece of elongated and late spermatids in the human testis. The patients' spermatozoa displayed multiple midpiece defects, including absent MS and central pair, scattered or forked axoneme and incomplete plasma membrane. Spermatozoa from mice showed parallel defects in the midpiece. Moreover, two patients were treated with intracytoplasmic sperm injection and achieved good outcomes.
CONCLUSION
Our findings prove for the first time that defects in cause asthenozoospermia and multiple midpiece defects in humans.
Topics: Animals; Humans; Male; Mice; Asthenozoospermia; Infertility, Male; Mice, Knockout; Mutation; Semen; Sperm Motility; Spermatozoa; Testis; Armadillo Domain Proteins
PubMed: 35534203
DOI: 10.1136/jmedgenet-2021-108137 -
Animals : An Open Access Journal From... Oct 2019The morphological and morphometric characterization of spermatozoa has been used as a taxonomic and phylogenetic tool for different species of mammals. We evaluated and...
The morphological and morphometric characterization of spermatozoa has been used as a taxonomic and phylogenetic tool for different species of mammals. We evaluated and compared the sperm morphometry of five neotropical primate species: , and of family Atelidae; and (=) and (=) of family Cebidae. After the collection of semen samples, the following parameters were measured on 100 spermatozoa from each specimen: Head Length, Head Width, Acrosome Length, Midpiece Length, Midpiece Width and Tail Length. Considering the available literature on sperm morphometry, we gathered data of 75 individuals, from 20 species, 8 genera and 2 families. These data were superimposed on a phylogeny to infer the possible direction of evolutionary changes. Narrower and shorter spermatozoa seem to be the ancestral form for Cebidae, with a trend toward wider and larger heads in derived groups. The spermatozoa of Atelidae may show an increase in total length and midpiece length. Sperm heads would have become narrower in the more derived groups of . Sperm length may increase in the more derived species in both families. Our results are discussed in the context of sperm competition and sexual selection.
PubMed: 31640171
DOI: 10.3390/ani9100839 -
Life (Basel, Switzerland) Jul 2021F-neuroprostanes (F-NeuroPs), derived from the oxidative metabolization of docosahexaenoic acid (DHA), are considered biomarkers of oxidative stress in neurodegenerative...
F-neuroprostanes (F-NeuroPs), derived from the oxidative metabolization of docosahexaenoic acid (DHA), are considered biomarkers of oxidative stress in neurodegenerative diseases. Neurons and spermatozoa display a high DHA content. NeuroPs might possess biological activities. The aim of this in vitro study was to investigate the biological effects of chemically synthetized 4-F-NeuroP and 10-F-NeuroP in human sperm. Total progressive sperm motility ( < 0.05) and linearity ( = 0.016), evaluated by a computer-assisted sperm analyzer, were significantly increased in samples incubated with 7 ng F-NeuroPs compared to non-supplemented controls. Sperm capacitation was tested in rabbit and swim-up-selected human sperm by chlortetracycline fluorescence assay. A higher percentage of capacitated sperm ( < 0.01) was observed in samples incubated in F-NeuroPs than in the controls. However, the percentage of capacitated sperm was not different in F-NeuroPs and calcium ionophore treatments at 2 h incubation. The phosphorylated form of AMPKα was detected by immunofluorescence analysis; after 2 h F-NeuroP incubation, a dotted signal appeared in the entire sperm tail, and in controls, sperm were labeled in the mid-piece. A defined level of seminal F-NeuroPs (7 ng) showed a biological activity in sperm function; its addition in sperm suspensions stimulated capacitation, increasing the number of sperm able to fertilize.
PubMed: 34357027
DOI: 10.3390/life11070655 -
Theriogenology Jul 2020The nerve growth factor (NGF), a member of the neurotrophins family, plays an important role in the nervous system but also in the reproductive apparatus and in sperm... (Review)
Review
The nerve growth factor (NGF), a member of the neurotrophins family, plays an important role in the nervous system but also in the reproductive apparatus and in sperm traits. The aim of this review is to summarize the effect of NGF on sperm functions of mammals. NGF was detected in seminal plasma of many animal species and its receptors, TrkA and p75NTR, are present in both epididymal and ejaculated sperm. The NGF, either endogenous or exogenous, may affects the kinetics and other sperm traits (e.g. capacitation, apoptosis, necrosis and acrosome reaction) and these effects appear modulated by the different receptors involved (TrkA or p75NTR). Although the animal species can affect the localization of receptors, TrkA seems mainly to be confined in the head and p75NTR in the midpiece and tail. Considering that some seminal disorders and sperm traits have been correlated with a lower NGF concentration, this review provides recent insights on the role of NGF on sperm cells and the possible mechanism implicated.
Topics: Animals; Fertility; Gene Expression Regulation; Humans; Male; Mammals; Nerve Growth Factor; Species Specificity; Spermatozoa
PubMed: 32000995
DOI: 10.1016/j.theriogenology.2020.01.039 -
Science Bulletin May 2020Impaired flagellar development and impaired motility of sperm is a cause of infertility in males. Several genes, including those of the AKAP, CCDC, CFAP, and DNAH...
Impaired flagellar development and impaired motility of sperm is a cause of infertility in males. Several genes, including those of the AKAP, CCDC, CFAP, and DNAH families, among others, are involved in the "multiple morphological abnormalities of the flagella" (MMAF) phenotype; these are the most common causes of male infertility. The Cilia-and flagella-associated protein (CFAP) family includes six members reported to cause MMAF phenotypes: CFAP43, CFAP44, CFAP69, CFAP65, CFAP70, and CFAP251. Here, we found that cilia-and flagella-associated protein 61 (Cfap61) is highly expressed specifically in murine testes and show that the Cfap61-knockout male mice demonstrate MMAF phenotype, including sperm with short, coiled, and irregular flagella. Deletion of Cfap61 resulted in severe morphological and behavior abnormalities in sperm, reduced total sperm counts, impaired sperm motility, and led to male infertility. Notably, absence of Cfap61 impaired sperm flagella ultrastructural abnormalities on account of numerous distortions in multiple flagellum components. Immunostaining experiments in wild-type mice and healthy adult humans indicated that Cfap61 is initially localized at the neck of sperm, where it potentially functions in flagellum formation, and is later localized to the midpiece of the sperm. Thus, our study provides compelling evidence that dysregulation of Cfap61 affects sperm flagellum development and induces male infertility in mice. Further investigations of the CFAP61 gene in humans alongside clinical evidence showing MMAF phenotype in humans should contribute to our understanding of developmental processes underlying sperm flagellum formation and the pathogenic mechanisms that cause male infertility.
PubMed: 36659204
DOI: 10.1016/j.scib.2020.01.023 -
Translational Andrology and Urology Apr 2020The pathogenesis of teratozoospermia (<4% morphologically normal sperm cells) and the relationship between sperm morphological abnormalities and abnormal sperm nuclear...
BACKGROUND
The pathogenesis of teratozoospermia (<4% morphologically normal sperm cells) and the relationship between sperm morphological abnormalities and abnormal sperm nuclear DNA fragmentation, which are considered indicators of male fertility, have not been elucidated. Our research was designed to determine the prevalence of different sperm DNA fragmentation (SDF) levels in men with teratozoospermia and to establish a discriminating threshold value for SDF in assessing sperm morphology.
METHODS
Basic semen characteristics and detailed sperm morphological analysis (head, neck, midpiece, and tail defects and excess residual cytoplasm) (WHO, 2010), and the nuclear sperm DNA dispersion test were performed on semen samples obtained from 523 men with teratozoospermia (n=296) and those without teratozoospermia (n=227).
RESULTS
Subjects with abnormal sperm morphology had not only lower results for standard sperm characteristics, including detailed sperm morphological abnormalities, but also a higher proportion of sperm cells with SDF men with normal sperm morphology. Moreover, significantly fewer subjects with low SDF levels (≤15%), more subjects with high SDF levels (>30%) and a higher odds ratio (OR) for having high SDF levels were found in the group of men with teratozoospermia men without teratozoospermia. However, the receiving operating characteristic (ROC) curve analysis indicated that a SDF >18% was a significant negative predictive value to distinguish between men with normal sperm morphology or men with abnormal sperm morphology. The optimal area under the ROC curve (AUC) was 0.746. In the group of men with teratozoospermia, a higher incidence of men with >18% SDF and a higher OR for having >18% SDF were observed. SDF negatively correlated with sperm number, morphologically normal sperm cells, sperm motility and sperm vitality but positively correlated with the teratozoospermia index (TZI) and detailed sperm morphological abnormalities.
CONCLUSIONS
The obtained findings demonstrated that: (I) detailed sperm structural defects coexist with abnormal nuclear sperm DNA dispersion, (II) men with teratozoospermia may have a higher risk for sperm DNA damage, (III) the calculated optimal SDF value of 18% measured by the DNA sperm dispersion test is the best criterion to predict normal and abnormal sperm morphology.
PubMed: 32420146
DOI: 10.21037/tau.2020.01.31