-
International Journal of Molecular... Feb 2022Globozoospermia is a rare and severe type of teratozoospermia characterized by the presence of round-headed, acrosomeless spermatozoa with cytoskeleton defects. Current...
Globozoospermia is a rare and severe type of teratozoospermia characterized by the presence of round-headed, acrosomeless spermatozoa with cytoskeleton defects. Current data support a negative relationship between globozoospermia and intracytoplasmic sperm injection (ICSI) outcomes, revealing the need to perform exhaustive studies on this type of sperm disorder. The aim of this study was to evaluate different structural, functional and molecular sperm biomarkers in total globozoospermia with proper embryo development after ICSI. The combination of field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) allowed us to identify and correlate eight morphological patterns with both types of microscopy. Additionally, results reported a high percentage of coiled forms, with cytoplasmic retentions around the head and midpiece. By fluorescent microscopy, we detected that most of the sperm showed tubulin in the terminal piece of the flagellum and less than 1% displayed tyrosine phosphorylation in the flagellum. Moreover, we did not detect chaperone Heat shock-related 70 kDa protein 2 (HSPA2) in 85% of the cells. Overall, these findings provide new insights into globozoospermia, which could have potential implications in improving sperm selection methods for assisted reproductive techniques.
Topics: Adult; Fluorescent Antibody Technique; Humans; Male; Microscopy, Electron, Scanning; Spermatozoa; Teratozoospermia
PubMed: 35163651
DOI: 10.3390/ijms23031729 -
Biology of Reproduction Apr 2022Sperm structural and functi onal defects are leading causes of male infertility. Patients with immotile sperm disorders suffer from axoneme failure and show a...
Sperm structural and functi onal defects are leading causes of male infertility. Patients with immotile sperm disorders suffer from axoneme failure and show a significant reduction in sperm count. The kinesin family member 3B (KIF3B) is one of the genes involved in the proper formation of sperm with a critical role in intraflagellar and intramanchette transport. A part of exon 2 and exons 3-5 of the KIF3B encodes a protein coiled-coil domain that interacts with intraflagellar transport 20 (IFT20) from the intraflagellar transport protein complex. In the present study, the coding region of KIF3B coiled-coil domain was assessed in 88 oligoasthenoteratozoospermic (OAT) patients, and the protein expression was evaluated in the mature spermatozoa of the case and control groups using immunocytochemistry and western blotting. According to the results, there was no genetic variation in the exons 3-5 of the KIF3B, but a new A>T variant was identified within the exon 2 in 30 patients, where nothing was detected in the control group. In contrast to healthy individuals, significantly reduced protein expression was observable in oligoasthenoteratozoospermic patients carrying variation where protein organization was disarranged, especially in the principal piece and midpiece of the sperm tail. Besides, the protein expression level was lower in the patients' samples compared to that of the control group. According to the results of the present study the KIF3B gene variation as well as lower protein expression leads to defects in sperm morphology and motility and consequently to male infertility.
Topics: Humans; Infertility, Male; Kinesins; Male; Proteins; Sperm Tail; Spermatogenesis; Spermatozoa
PubMed: 34918036
DOI: 10.1093/biolre/ioab226 -
Animal Reproduction Science Sep 2020Ultrastructural studies of the male gamete provide relevant complementary data of value for the clinical assessment of semen quality and assist in determining... (Review)
Review
Ultrastructural studies of the male gamete provide relevant complementary data of value for the clinical assessment of semen quality and assist in determining phylogenetic and structural/functional relationships. This is illustrated using semen samples and testicular material from vulnerable wild animals (cheetah and rhinoceros), commercially exploited exotic birds (ratites and tinamou) and poultry (chicken and duck). Transmission electron microscopy (TEM) was employed to record sperm and spermatid ultrastructural detail on a comparative basis. The power of the technique was demonstrated using normal and abnormal (the knobbed acrosome defect) formation of the acrosome in the cheetah and rhinoceros. The structural similarities of the defect across species was apparent. The determination of phylogenetic associations was illustrated by comparing structural characteristics between ratites (ostrich, emu and rhea), the tinamou and poultry (chicken and duck), highlighting the morphological peculiarities evident in the midpiece and proximal principal piece of the sperm tail. A clear distinction was obvious between the ratites and tinamou on the one hand and the Galliform and Anseriform birds on the other. The potential power of using molecular techniques in conjunction with ultrastructural studies to explain structural/functional relationships was demonstrated by describing a transient elaboration of the perinuclear theca that occurs during a specific stage of spermiogenesis in ratites, and which can only be imaged using TEM. The inherent aesthetic appeal of the structurally complex normal and defective male gamete was also emphasised.
Topics: Animals; Birds; Humans; Male; Mammals; Microscopy, Electron, Transmission; Phylogeny; Spermatozoa
PubMed: 32085922
DOI: 10.1016/j.anireprosci.2020.106306 -
Microscopy Research and Technique Dec 2023Sperm morphology is considered a species-specific character and has been used as a tool in the classification of numerous mammalian taxa. Neotropical bats have been...
Sperm morphology is considered a species-specific character and has been used as a tool in the classification of numerous mammalian taxa. Neotropical bats have been poorly studied, and important aspects on sperm morphology have not been elucidated. The aim of the present study was to describe and compare the sperm morphology and morphometry of Molossus molossus and Molossops temminckii. A total of 14 adults specimens were analyzed from the Colección Mamíferos Lillo, Universidad Nacional de Tucumán: five M. molossus and nine M. temminckii. The epididymis were extracted and macerated in Farmer's solution, followed by a coloration with different stains. To carry out the description and morphometric analysis, microphotographs were taken under an optical, epifluorescence, and scanning electron microscope (SEM). A total of 50 sperm from each individual were measured for morphometric analysis. The length and width of the head, midpiece and tail were taken as variables. Sperm from M. molossus and M. temminckii were practically identical, both morphologically and morphometrically. In both species, a distal bulge was observed at the end of the intermediate piece in a percentage greater than 85%. The main characteristics shared between the species were: presence of acrosomal blebs in the upper half of the head of the spermatozoa; cephalic equatorial segment with filiform ornamentations; intermembrane space of head apex wedge-shaped; helical middle piece and annulus at the end of middle piece. In the present study, SEM allowed us to visualize structures, such as acrosomal vesicles, that were not detected with other types of microscopy. RESEARCH HIGHLIGHTS: The similarities in the sperm morphology between M. molossus and M. temminckii were observed with three types of microscopy: optical, epifluorescence and scanning electron, and supported by morphometric and statistical analyses.
Topics: Animals; Male; Chiroptera; Semen; Spermatozoa; Epididymis; Acrosome
PubMed: 37572016
DOI: 10.1002/jemt.24396 -
Proceedings of the National Academy of... Nov 2021Efficient and targeted sperm motility is essential for animal reproductive success. Sperm from mammals and echinoderms utilize a highly conserved signaling mechanism in...
Efficient and targeted sperm motility is essential for animal reproductive success. Sperm from mammals and echinoderms utilize a highly conserved signaling mechanism in which sperm motility is stimulated by pH-dependent activation of the cAMP-producing enzyme soluble adenylyl cyclase (sAC). However, the presence of this pathway in early-branching metazoans has remained unexplored. Here, we found that elevating cytoplasmic pH induced a rapid burst of cAMP signaling and triggered the onset of motility in sperm from the reef-building coral in a sAC-dependent manner. Expression of sAC in the mitochondrial-rich midpiece and flagellum of coral sperm support a dual role for this molecular pH sensor in regulating mitochondrial respiration and flagellar beating and thus motility. In addition, we found that additional members of the homologous signaling pathway described in echinoderms, both upstream and downstream of sAC, are expressed in coral sperm. These include the Na/H exchanger SLC9C1, protein kinase A, and the CatSper Ca channel conserved even in mammalian sperm. Indeed, the onset of motility corresponded with increased protein kinase A activity. Our discovery of this pathway in an early-branching metazoan species highlights the ancient origin of the pH-sAC-cAMP signaling node in sperm physiology and suggests that it may be present in many other marine invertebrate taxa for which sperm motility mechanisms remain unexplored. These results emphasize the need to better understand the role of pH-dependent signaling in the reproductive success of marine animals, particularly as climate change stressors continue to alter the physiology of corals and other marine invertebrates.
Topics: Adenylyl Cyclases; Animals; Anthozoa; Biodiversity; Calcium; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Flagella; Homeostasis; Hydrogen-Ion Concentration; Male; Phosphorylation; Phylogeny; Reproduction; Sperm Motility; Spermatozoa
PubMed: 34810263
DOI: 10.1073/pnas.2109993118 -
Theriogenology Sep 2023Computer-assisted sperm morphometry analysis is an advanced tool which allows to precise measure sperm head parameters like length, width, area, and perimeter. On the...
Computer-assisted sperm morphometry analysis is an advanced tool which allows to precise measure sperm head parameters like length, width, area, and perimeter. On the basis of these and calculated parameters, morphometric subpopulations of spermatozoa can be distinguished. In many species, the distribution of subpopulation within the ejaculate is related to male fertility. There is no information about such a relation for domestic cats; therefore, the aim of this study was to evaluate whether spermatozoa from non-pedigree and purebred domestic cats differ in morphometric parameters. The second aim was to check if there is a relationship between sperm morphometry and fertility. Urethral semen was collected from 27 tomcats, divided into three study groups: non-pedigree cats of unknown fertility, purebred infertile cats and purebred fertile cats. The morphometric assessment was performed by CASMA, followed by principal component analysis and clustering. The results revealed huge intra- and inter-individual variation in sperm head morphometric parameters and three sperm-head morphometric subpopulations were identified in feline semen. Neither mean values of morphometric parameters nor the distribution of spermatozoa between morphometric subpopulations differ between non-pedigree cats of unknown fertility and purebred infertile and fertile cats. We hypothesize that other factors, especially abnormalities of the midpiece and tail, and overall worse quality of the semen of infertile males could have masked the effect of subtle changes in the sperm head morphometry.
PubMed: 37311263
DOI: 10.1016/j.theriogenology.2023.06.006 -
Journal of Evolutionary Biology Oct 2019Post-copulatory sexual selection, and sperm competition in particular, is a powerful selective force shaping the evolution of sperm morphology. Although mounting...
Post-copulatory sexual selection, and sperm competition in particular, is a powerful selective force shaping the evolution of sperm morphology. Although mounting evidence suggests that post-copulatory sexual selection influences the evolution of sperm morphology among species, recent evidence also suggests that sperm competition influences variation in sperm morphology at the intraspecific level. However, contradictory empirical results and limited taxonomic scope have led to difficulty in assessing the generality of sperm morphological responses to variation in the strength of sperm competition. Here, we use phylogenetically controlled analyses to explore the effects of sperm competition on sperm morphology and variance in sharks, a basal vertebrate group characterized by wide variation in rates of multiple mating by females, and consequently sperm competition risk. Our analyses reveal that shark species experiencing greater levels of sperm competition produce sperm with longer flagella and that sperm flagellum length is less variable in species under higher sperm competition risk. In contrast, neither the length of the sperm head and midpiece nor variation in sperm head and midpiece length was associated with sperm competition risk. Our findings demonstrate that selection influences both the inter- and intraspecific variation in sperm morphology and suggest that the flagellum is an important target of sexual selection in sharks. These findings provide important insight into patterns of selection on the ejaculate in a basal vertebrate lineage.
Topics: Animals; Biological Evolution; Female; Male; Models, Genetic; Phylogeny; Sex Determination Processes; Sharks; Spermatozoa
PubMed: 31250483
DOI: 10.1111/jeb.13501 -
Biomolecules Mar 2023Proteasomes are highly sophisticated protease complexes that degrade non-lysosomal proteins, and their proper regulation ensures various biological functions such as...
Proteasomes are highly sophisticated protease complexes that degrade non-lysosomal proteins, and their proper regulation ensures various biological functions such as spermatogenesis. The proteasome-associated proteins, PA200 and ECPAS, are predicted to function during spermatogenesis; however, male mice lacking each of these genes sustain fertility, raising the possibility that these proteins complement each other. To address this issue, we explored these possible roles during spermatogenesis by producing mice lacking these genes (double-knockout mice; dKO mice). Expression patterns and quantities were similar throughout spermatogenesis in the testes. In epididymal sperm, PA200 and ECPAS were expressed but were differentially localized to the midpiece and acrosome, respectively. Proteasome activity was considerably reduced in both the testes and epididymides of dKO male mice, resulting in infertility. Mass spectrometric analysis revealed LPIN1 as a target protein for PA200 and ECPAS, which was confirmed via immunoblotting and immunostaining. Furthermore, ultrastructural and microscopic analyses demonstrated that the dKO sperm displayed disorganization of the mitochondrial sheath. Our results indicate that PA200 and ECPAS work cooperatively during spermatogenesis and are essential for male fertility.
Topics: Male; Animals; Mice; Proteasome Endopeptidase Complex; Semen; Spermatogenesis; Spermatozoa; Mice, Knockout; Phosphatidate Phosphatase; Nuclear Proteins
PubMed: 37189334
DOI: 10.3390/biom13040586 -
Poultry Science Apr 2021In birds, sperm storage tubules (SST) located in the utero-vaginal junction are thought to be a site of sperm selection; however, the exact mechanism of sperm selection...
In birds, sperm storage tubules (SST) located in the utero-vaginal junction are thought to be a site of sperm selection; however, the exact mechanism of sperm selection is poorly understood. Here, we investigated sperm entry into the SST and subsequent fertilization success under a competitive situation created by artificial insemination of a sperm mixture obtained from 2 males. We employed 2 quail strains, a wild-type and a dominant black (DB) type, as this allows easy assessment of paternity by feather coloration. We found paternity of embryos was biased toward DB males when a sperm mix with similar sperm numbers from the 2 males strains was artificially inseminated into females. Our novel sperm staining method with 2 different fluorescent dyes showed that the DB-biased fertilization was because of the better ability of DB sperm to enter the SST. Moreover, we found that DB sperm had a longer flagellum and midpiece. These characteristics probably allow sperm to swim faster in a high viscosity medium, which may be a similar environment to the lumen of the female reproductive tract. Our results indicated that sperm competition occurs to win a place in the SST and that filling the SST with their own spermatozoa is a critical step to achieve better fertilization success for the male Japanese quail.
Topics: Animals; Chickens; Coturnix; Female; Fertilization; Insemination, Artificial; Male; Spermatozoa
PubMed: 33610899
DOI: 10.1016/j.psj.2021.01.003 -
Frontiers in Cell and Developmental... 2022Chemotaxis is a highly conserved physiological event required for directed sperm movement during fertilization. Recently, studies from our laboratory have identified...
Chemotaxis is a highly conserved physiological event required for directed sperm movement during fertilization. Recently, studies from our laboratory have identified N-formyl-L-aspartate (NFA) as a sperm chemoattractant. NFA is a known agonist for the beta-2-adrenergic receptor (β-2-AR) that regulates cAMP production and Ca mobilization in somatic cells. As these downstream signaling molecules are also reported to be involved in sperm chemotaxis, in the present study we investigated the putative mechanism/s by which NFA may mediate chemotaxis. Toward this, the expression and localization of β-2-AR in sperm were studied by Western blot and indirect immunofluorescence, respectively. The responses of sperm to various concentration gradients of NFA and ICI-118,551, a β-2-AR specific antagonist, were evaluated using the microfluidics device-based chemotaxis assay. The intracellular concentration of Ca, on exposure to NFA, was analyzed using FURA-2 AM-based fluorimetric assay. Furthermore, the effect of NFA on sperm capacitation and acrosome reaction was evaluated using Western blot and immunofluorescence. NFA exhibited a bell-shaped dose-response curve typical of chemotaxis, with maximum response observed at 0.01M NFA, beyond which it was inhibitory; β-2-AR localization was seen on the sperm head and the mid-piece region of the flagella. Inhibition of sperm chemotaxis by ICI-118,551 confirms that sperm respond chemotactically to NFA β-2-AR. Interestingly, at the concentration used for chemotaxis, NFA induced an increase in the intracellular Ca but decreased cAMP in capacitating sperm. However, NFA did not induce capacitation as seen from the lack of effect on tyrosine phosphorylation and membrane potential of uncapacitated sperm. Acrosome evaluation of NFA-treated sperm using PSA-FITC staining showed no effect on the acrosome structure. Our data thus provide evidence indicating that NFA induces sperm chemotaxis and the chemotactic response of sperm to NFA from the ovulatory phase of oviductal fluid is mediated through the β-2-AR on sperm possibly via non-canonical signaling.
PubMed: 36211455
DOI: 10.3389/fcell.2022.959094