Testicular ACE regulates sperm metabolism and fertilization through the transcription factor PPARγ.

Testis angiotensin-converting enzyme (tACE) plays a critical role in male fertility, but the mechanism is unknown. By using ACE C-domain KO (CKO) mice which lack tACE activity, we found that ATP in CKO sperm was 9.4-fold lower than WT sperm. Similarly, an ACE inhibitor (ACEi) reduced ATP production in mouse sperm by 72%. Metabolic profiling showed that tACE inactivation severely affects oxidative metabolism with decreases in several Krebs cycle intermediates including citric acid, cis-aconitic acid, NAD, α-ketoglutaric acid, succinate, and L-malic acid. We found that sperms lacking tACE activity displayed lower levels of oxidative enzymes (CISY, ODO1, MDHM, QCR2, SDHA, FUMH, CPT2, and ATPA) leading to a decreased mitochondrial respiration rate. The reduced energy production in CKO sperms leads to defects in their physiological functions including motility, acrosine activity, and fertilization in vitro and in vivo. Male mice treated with ACEi show severe impairment in reproductive capacity when mated with female mice. In contrast, an angiotensin II receptor blocker (ARB) had no effect. CKO sperms express significantly less peroxisome proliferators-activated receptor gamma (PPARγ) transcription factor, and its blockade eliminates the functional differences between CKO and WT sperms, indicating PPARγ might mediate the effects of tACE on sperm metabolism. Finally, in a cohort of human volunteers, in vitro treatment with the ramipril or a PPARγ inhibitor reduced ATP production in human sperm and hence its motility and acrosine activity. These findings may have clinical significance since millions of people take ACEi daily, including men who are reproductively active.

Gss deficiency causes age-related fertility impairment via ROS-triggered ferroptosis in the testes of mice.

Glutathione synthetase (GSS) catalyzes the final step in the synthesis of glutathione (GSH), a well-established antioxidant. Research on the specific roles of the Gss gene during spermatogenesis remains limited due to the intricate structure of testis. In this study, we identified pachytene spermatocytes as the primary site of GSS expression and generated a mouse model with postnatal deletion of Gss using Stra8-Cre (S8) to investigate the role of GSS in germ cells. The impact of Gss knockout on reducing male fertility is age-dependent and caused by ferroptosis in the testis. The 2-month-old S8/Gss-/- male mice exhibited normal fertility, due to a compensatory increase in GPX4, which prevented the accumulation of ROS. With aging, there was a decline in GPX4 and an increase in ALOX15 levels observed in 8-month-old S8/Gss-/- mice, resulting in the accumulation of ROS, lipid peroxidation, and ultimately testicular ferroptosis. We found that testicular ferroptosis did not affect spermatogonia, but caused meiosis disruption and acrosome heterotopia. Then the resulting aberrant sperm showed lower concentration and abnormal morphology, leading to reduced fertility. Furthermore, these injuries could be functionally rescued by inhibiting ferroptosis through intraperitoneal injection of GSH or Fer-1. In summary, Gss in germ cells play a crucial role in the resistance to oxidative stress injury in aged mice. Our findings deepen the understanding of ferroptosis during spermatogenesis and suggest that inhibiting ferroptosis may be a potential strategy for the treatment of male infertility.

Localization and Distribution of Testicular Angiotensin I Converting Enzyme (ACE) in Neck and Mid-Piece of Spermatozoa from Infertile Men in Relation to Sperm Motility.

Testicular angiotensin converting enzyme (ACE) is known to play an essential role in the male reproduction and fertility. Data about tACE in cases of male infertility are quite scarce, and in this respect we aimed to study localization and distribution of tACE protein in the neck and mid-piece of spermatozoa from pathological samples in relation to sperm motility. The enzyme expression during capacitation and acrosome reaction was quantitatively assessed. In human ejaculated spermatozoa tACE is localized on sperm plasma membrane of the head, the neck and mid-piece of the tail. The immunoreactivity becomes stronger in capacitated spermatozoa followed by a decrease in acrosome reacted sperm. In different cases of semen pathology (oligozoospermia, asthenozoospermia and teratozoospermia) fluorescent signals in the neck and mid-piece are in punctate manner whereas in normozoospermia they were uniformly distributed. The expression area of tACE the neck and mid-piece was decreased in ejaculated and capacitated sperm from pathological semen samples compared to normospermia. Significant positive correlation was established between tACE area and progressive sperm motility, whereas with immotile sperm the correlation was negative. Our data suggest that proper distribution of tACE in the neck and mid-piece is required for normal sperm motility that could be used as a novel biomarker for male infertility.

Identification and Characterization of the Pyruvate Dehydrogenase E1 Gene in the Oriental River Prawn, Macrobrachium nipponense.

Pyruvate dehydrogenase E1 (PDHE1) is thought to play essential roles in energy metabolism, and a previous study suggested that it also has potential regulatory roles in male sexual development in the oriental river prawn, Macrobrachium nipponense. In this study, we used rapid amplification of cDNA ends, quantitative polymerase chain reaction (qPCR), in situ hybridization, western blotting, RNA interference (RNAi), and histological analyses to assess the potential functions of Mn-PDHE1 in the sexual development of male M. nipponense. The full cDNA sequence of Mn-PDHE1 was 1,614 base pairs long, including a 1,077 base pair open reading frame that encodes 358 amino acids. qPCR analysis revealed the regulatory functions of PDHE1 in male sexual development in M. nipponense and in the metamorphosis process. In situ hybridization and western blot results indicated that PDHE1 was involved in testis development, and RNAi analysis showed that PDHE1 positively regulated the expression of insulin-like androgenic gland factor in M. nipponense. Compared with the cell types in the testes of control prawns, histological analysis showed that the number of sperm was dramatically lower after test subjects were injected with Mn-PDHE1 dsRNA, whereas the numbers of spermatogonia and spermatocytes were higher. Sperm constituted only 1% of cells at 14 days after injection in the RNAi group. This indicated that knockdown of the expression of PDHE1 delayed testis development. Thus, PDHE1 has positive effects on male sexual development in M. nipponense. This study highlights the functions of PDHE1 in M. nipponense and its essential roles in the regulation of testis development.

Circadian effects of ionizing radiation on reproductive function and clock genes expression in male mouse.

BACKGROUND: Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far. METHODS: Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-ß, or Ror-γ. RESULTS: Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-ß, or Ror-γ) in testis, with alteration in the rhythm parameters. CONCLUSION: These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.

The protective effect of crocin on cisplatin-induced testicular impairment in rats.

BACKGROUND: Side effects of cisplatin (CIS) such as testicular toxicity restrict its clinical use. Instead, evidence indicates that crocin (CR) has synergistic anti-cancer potential with CIS and exhibited beneficial effects on CIS-induced hepatorenal damage. The aim of this study was to investigate the protective potential of CR against CIS-induced testicular toxicity in rats. METHODS: Fifty adult male Wistar rats randomly assigned to five equal groups including control, CIS, and CIS plus CR at doses of 6.25 mg/kg (CIS + CR6.25), 25 mg/kg (CIS + CR25), and 100 mg/kg (CIS + CR100). CIS and CIS + CR groups received a single intraperitoneally (i.p.) injection of CIS (7 mg/kg). CR (6.25-100 mg/kg i.p.) injections were started three days before the CIS injection and continued once a day for up to 13 days. On the 14th day, all animals were sacrificed and their blood samples and testes were removed for biochemical and histological analyses. RESULTS: Compared to the control group, CIS significantly decreased relative testis weight (0.28 vs. 0.39, p < 0.001), testosterone level (0.3 vs. 2.31 ng/mL, p < 0.001), germinal layer area (25,886 vs. 35,320 µm2, p < 0.001), superoxide dismutase (SOD) (0.9 vs.1.73 U/mg, p < 0.001) and increased testicular lipid peroxidation (3.05 vs. 15.35 nmol/mg, p < 0.001). CR at 25 mg/kg ameliorated testicular lipid peroxidation and enhanced SOD activity compared to CIS group (p < 0.05). Besides, CR treatment at the maximum dose (100 mg/kg) resulted in reversing CIS effects on testis weight, testosterone level, SOD, lipid peroxidation, and germinal layer area. CONCLUSIONS: These findings demonstrated that CR co-treatment could prevent CIS-induced testicular toxicity in rats.

A Chemoproteomics Approach to Determine the Mechanism of Testicular Toxicity for the Bruton's Tyrosine Kinase Inhibitor CC-292.

During drug development, potential safety issues can occur at any time. Understanding the cause of a toxicity can help with deciding on how to advance the drug development program. Chemoproteomics provides a way to help understand the cause of a toxicity wherein the affected tissue is accessible and can be probed with a covalently binding compound that is analogous to the offending drug. In this case, N-(3-(5-fluoro-2-(4-(2-methoxyethoxy)phenylamino)pyrimidin-4-ylamino)phenyl)acrylamide (CC-292), a covalently binding Bruton's tyrosine kinase inhibitor, had produced testicular toxicity in rodents. Experiments were conducted using a CC-292 analog that could be chemically modified with biotin to probe rodent testes homogenates for potential binding sites that were subsequently recovered with avidin beads. These biotin-tagged proteins undergo trypsin digest on the avidin beads to yield peptides that are identified using mass spectrometry. Two proteins were identified from the testicular homogenates of both rats and mice, namely retinal dehydrogenase 1 (ALDH1A1) and retinal dehydrogenase 2 (ALDH1A2). Literature confirmed a link between inhibition of these enzymes and testicular toxicity. Subsequently, molecular modeling was used to demonstrate that CC-292 can be docked into both the nicotinamide adenine dinucleotide and retinal binding pockets of the analogous human ALDH1A2 enzyme. These data suggest that the off-target binding site for CC-292 on retinal dehydrogenase enzymes may provide a mechanistic explanation to the testicular toxicity observed in rodents and that there may be a potential concern for human male fertility. SIGNIFICANCE STATEMENT: Biotinylated covalently binding drug analogues are used to enrich bound proteins from tissue homogenates wherein toxicity was observed in rodents. Bound proteins were subsequently identified by mass spectroscopy. Competition of the analog binding with the parent inhibitor itself and three-dimensional molecular modeling were used to establish a likely link between the off-targets of CC-292, ALDH1A1, and ALDH1A2 with potential testicular toxicity.

3D structure prediction, dynamic investigation and rational construction of an epitope-masked thermostable bovine hyaluronidase.

Hyaluronidase (HAase) from bovine testes (BTH) has long been used in broad pharmaceutical areas, while it is associated with drawbacks in aspects of solubility, immunogenicity and pharmacokinetics. These issues can be addressed by gaining structural insights and designing rational modifications to the enzyme structure, as proposed in this study. A 3D structural model was built for HAase and underwent 40 ns of molecular dynamic simulation to examine its thermostability under normal, melting, and extreme conditions. The enzyme activity of BTH was measured against temperature and pH by kinetic assays. The interaction of bovine HAase with HA and chondroitin was defined by molecular docking. Furthermore, immunogenic properties of the enzyme were explored by immunoinformatics. Thermal effects on bovine HAase structural model and the HAase interactions with its substrates were described. We identified some B- and T-cell epitopes and showed that the protein could be recognized by human immune receptor molecules. Epitope masking by adding polyethylene glycol (PEG) to amine groups of residues presenting on the surface of the protein structure was adopted as a surface modification to enhance pharmacological properties of BTH. Assays showed that PEGylated BTH had higher thermostability and similar activity compared to the native enzyme.

Riboflavin recovery of spermatogenic dysfunction via a dual inhibition of oxidative changes and regulation of the PINK1-mediated pathway in arsenic-injured rat model.

Arsenic trioxide (As2O3) poisoning and associated potential lesions are of a global concern. Inversely, riboflavin (vitamin B2, VB2) as a component of flavoproteins could play a vital role in the spermatogenic enzymatic reactions. Thus, this research aimed to explore potential beneficial roles of VB2 during As2O3-injured-toxicity. Rats were randomly allocated into 4 groups (n=8/group) and challenged as follows (for 30 days continuously): Group 1 received normal saline; Group 2 was treated with 3 mg As2O3/L; Group 3 received 40 mg VB2/L; Group 4 received 3 mg As2O3/L + 40 mg VB2/L. Both As2O3 and VB2 were dissolved in deionized water. Malondialdehyde (MDA), Glutathione Peroxidase (GSH-Px), Superoxide dismutase (SOD), and Catalase (CAT) were assessed for the oxidative profile, while TAS (Total Antioxidative Status) levels were evaluated for the antioxidant system, in both serum and testicular tissue. P<0.05 was considered statistically significant. The results show that As2O3 significantly decreased the body weight, testicular weight and testis volume, semen quality and testicular cell count (p<0.05). Furthermore, MDA content in the testicular tissue of the As2O3 group rats was significantly higher in comparison to the vehicle group (p<0.05). Likewise, TAS and the activities of GSH-Px, CAT and SOD were reduced (p<0.05) when compared to the control. As(2)O(3) induced testicular damage and seminiferous tubular atrophy. Monodansylcadaverine assays mirrored the histopathology observations. Meanwhile, As2O3 upregulated the expression of mitophagy-related genes including PINK1, Parkin, USP8, LC3-I, Fis1 and Mfn2. The p38 gene, responsible to stress stimuli, was also upregulated by As2O3 administration. Meanwhile, exposure to VB2 led to a significant decrease of the expression levels of mitophagy related genes. Our study revealed that VB2 supplementation protected testicular structures against As2O3-induced injury via a dual inhibition of oxidative changes and a regulation of the PINK1-mediated pathway.

Phosphatidylinositol 3-Kinase δ-Specific Inhibitor-Induced Changes in the Ovary and Testis in the Sprague Dawley Rat and Cynomolgus Monkey.

Phosphatidylinositol 3-kinase (PI3K) δ is a lipid kinase primarily found in leukocytes, which regulates important cell functions. AMG2519493 was a PI3K δ-specific inhibitor in development for treatment of various inflammatory diseases. AMG2519493-related changes in the male and/or female reproductive organs were observed in the 1- and 3-month oral repeat dose toxicology studies in the rat and cynomolgus monkey. Hemorrhagic corpora lutea cysts and increased incidence of corpora lutea cysts without hemorrhage were observed in the ovaries at supra pharmacological doses in the rat. A decrease in seminiferous germ cells in the testis, indicative of spermatogenesis maturation arrest, was observed in both the rat and cynomolgus monkey. Although the characteristics were comparable, the drug systemic exposures associated with the testicular changes were very different between the 2 species. In the rat, the testicular change was only observed at supra pharmacologic exposure. Isotype assessment of PI3K signaling in rat spermatogonia in vitro indicated a role for PI3K ß, but not δ, in the c Kit/PI3K/protein kinase B signaling pathway. Therefore, changes in both the ovary and testis of the rat were considered due to off target effect as they only occurred at suprapharmacologic exposure. In contrast, the testicular changes in the cynomolgus monkey (decrease in seminiferous germ cells) occurred at very low doses associated with PI3K δ-specific inhibition, indicating that the PI3K δ isoform may be important in spermatogenesis maturation in the cynomolgus monkey. Our results suggest species-related differences in PI3K isoform-specific control on reproductive organs.

PRSS50 is a testis protease responsible for proper sperm tail formation and function.

Multiple morphological abnormalities of the sperm flagella (MMAF) are a major cause of asthenoteratozoospermia. We have identified protease serine 50 (PRSS50) as having a crucial role in sperm development, because Prss50-null mice presented with impaired fertility and sperm tail abnormalities. PRSS50 could also be involved in centrosome function because these mice showed a threefold increase in acephalic sperm (head-tail junction defect), sperm with multiple heads (spermatid division defect) and sperm with multiple tails, including novel two conjoined sperm (complete or partial parts of several flagellum on the same plasma membrane). Our data support that, in the testis, as in tumorigenesis, PRSS50 activates NFκB target genes, such as the centromere protein leucine-rich repeats and WD repeat domain-containing protein 1 (LRWD1), which is required for heterochromatin maintenance. Prss50-null testes have increased IκκB, and reduced LRWD1 and histone expression. Low levels of de-repressed histone markers, such as H3K9me3, in the Prss50-null mouse testis may cause increases in post-meiosis proteins, such as AKAP4, affecting sperm formation. We provide important insights into the complex mechanisms of sperm development, the importance of testis proteases in fertility and a novel mechanism for MMAF.

The protein phosphatase with EF-hand domain 1 is a calmodulin-binding protein that interacts with proteins involved in sperm capacitation, binding to the zona pellucida, and motility.

Spermatozoa are highly specialized cells whose fertilizing and motility functions highly depend on intracellular Ca2+ -mediated events and protein posttranslational modifications like phosphorylation. Our group previously identified PPEF1, the Ser/Thr phosphatase with EF-hand domain 1, among calmodulin-affinity pulled down sperm proteins. As the mammalian ortholog of the Drosophila phosphatase rdgC that dephosphorylates rhodopsin, PPEF1 has been studied mostly in the retina. The presence and importance of this Ca2+ /calmodulin-binding protein phosphatase has not been studied in sperm or testicular functions despite its high expression level. In this study, we show that PPEF1 is present in testicular germ cells, and in mouse, human and bull spermatozoa where it is localized predominantly in the neck and acrosome areas. Different transcript variants encoding four predicted isoforms were detected by reverse transcription polymerase chain reaction in bull testis, spermatocytes and spermatids. Phosphatase activity of immunoprecipitated sperm PPEF1 was detected using the substrate pNPP and analysis of the coimmunoprecipitated proteins reveal an enrichment in the biological processes of sperm capacitation, binding to the zona pellucida and motility. Although this is the first demonstration of the presence of PPEF1 in sperm and testicular germ cells, its involvement in sperm fertilizing ability and motility, and the mechanisms regulating its activity remain to be further investigated.

Modulatory Role of Vitamin E on Proton Pump (ATPase) Activity of Cadmium Chloride-Induced Testicular Damage in Wistar Rats.

Proton pumps are membrane-bound enzymes important in generating gradients that help in maintaining cellular ion homeostasis, cell membrane potential, water, and solute transport across the cell surface. This study investigated the modulatory role of vitamin E on proton pump activity and reproductive parameters in cadmium-induced testicular damage. Twenty (20) male Wistar rats weighing between 180 and 200 g were sorted into 4 groups of five rats each. Group I served as the control and was given normal saline orally, Group II rats were treated with a single dose of 2 mg/kg BW cadmium chloride (CdCl2) intraperitoneally, Group III rats were given 100 mg/kg BW of vitamin E orally, and Group IV rats were given 100 mg/kg BW of vitamin E orally for 30 days prior to intraperitoneal administration of single dose of 2 mg/kg BW of cadmium chloride. The rats were anaesthetized with diethyl ether, and blood samples were obtained for sex hormonal analysis; caudal epididymis was dissected for sperm count, motility, and viability, and the testis were homogenized for lipid peroxidation and proton pump (Na+/K+ ATPase, Ca2+ ATPase, and Mg2+ ATPase) activity. Proton pump activity was assayed spectrophotometrically using the Stewart method to determine the inorganic phosphate level. Histopathological changes of the testis were also studied. The group treated with CdCl2 showed a significant (p < 0.05) decrease in proton pump activity, sperm count, and motility and a significant (p < 0.05) increase in malondialdehyde level when compared with the control group. The CdCl2-treated group also showed decrease reproductive organ weights and hormonal levels and cause necrosis of spermatogonia lining the seminiferous tubules. Rats treated with vitamin E orally for 30 days prior to CdCl2 exposure showed improvement in proton pump activity, a significant (p < 0.05) increase in sperm parameters and luteinizing hormonal level, and a decrease in the lipid peroxidation level as compared with the CdCl2 group. This study showed that vitamin E ameliorated the toxic effect of CdCl2 on proton pump activity in the testes, hence improving testicular integrity, structures, and functions.

Rescue effect of sodium acetate in diabetes mellitus-associated testicular dysfunction is accompanied by PCSK9 modulation.

Diabetes mellitus (DM) is a global health burden, affecting about 463 million of the adult population worldwide. Approximately 94% of diabetic male individuals develop varying degrees of testicular disorders (TDs), which usually result in hypogonadism, hypotestosteronemia and defective spermatogenesis and steroidogenesis. Short chain fatty acids (SCFAs) have shown potential benefits in metabolic health. However, its effect on TD associated with DM is not clear. Howbeit, the present study investigated the hypothesis that SCFAs, acetate would ameliorate TD accompanying DM, possibly by suppressing proprotein convertase subtilisin/kexin type 9 (PCSK9). Male Wistar rats (210-240 g) were allotted into groups (n = 6/group): control (vehicle; po), DM with/without 200 mg/kg (po) of sodium acetate (SAc). Diabetes was induced by streptozotocin 65 mg/kg (iv) after a dose of nicotinamide (110 mg/kg). Semen/biochemical and histological analyses were performed with appropriate methods. In addition to hyperglycemia, hyperinsulinemia and reduced insulin sensitivity, DM led to increased serum and testicular triglyceride or total cholesterol/high-density lipoprotein cholesterol ratio, low-density lipoprotein cholesterol, malondialdehyde, TNF-α, IL-6 and PCSK9 as well as reduced high-density lipoprotein cholesterol and glutathione. Moreover, DM caused TD which is characterized by altered sperm parameters, disrupted tissue architecture, atrophied seminiferous tubules, deleterious spermatogonia, disappearance of lumen and cellular degeneration as well as decreased luteinizing hormone and testosterone. However, the administration of SAc attenuated these alterations. The study demonstrates that DM-induced TD is accompanied by elevated PCSK9. The results however suggest that SAc rescues testicular disorder/dysfunction associated with DM by suppression of PCSK9 and improvement of insulin sensitivity.

Low-Se Diet Can Affect Sperm Quality and Testicular Glutathione Peroxidase-4 activity in Rats.

This study aimed to observe the influence of selenium (Se) deficiency on sperm quality and selenoprotein expression in rats. Four-week male Wista rats were randomly divided into three groups: Se-A, Se-L, and Se-D (respectively for Se- adequate, low, and deficient group). After 9 weeks, the rats were sacrificed by anesthesia, with the cauda epididymidis quickly fetched for sperm count, motility, and deformity. Meanwhile the blood, liver, brain, heart, and testis were collected for Se and biochemical analysis. It was found that the rats in Se-D had poor growth, while the Se concentrations in blood, liver, and heart for Se-D decreased significantly, compared with Se-A and Se-L (p < 0.01). But no significant difference was observed in testis and brain and also no statistical significance for sperm count. The sperm motility for Se-A (63.07%) was significantly higher than Se-L (53.91%) and Se-D (54.15%). Deformities were observed in both Se-L and Se-D. Both glutathione peroxidases (GPxs) and selenoprotein-P (SEPP1) levels in plasma and tissues of Se-D were significantly lower than those of Se-A and Se-L (p < 0.01). The SEPP1 levels in heart and brain of Se-L were lower than Se-A (p < 0.01). There was no statistical difference for GPx1 between Se-A and Se-L. The GPx4 level in testis of Se-L was lower than Se-A (p < 0.05). However, the SEPP1 in plasma, liver, testis, and the GPx3 level in plasma of Se-L were higher than those of Se-A (p < 0.05 or p < 0.01). Our results show that dietary Se deficiency could reduce GPx4 and SEPP1 expression in testis, which further influence sperm motility and may cause sperm deformity. Selenoprotein expression in some tissues of Se-L was higher than that of Se-A, but sperm quality and GPx4 expression in testis were not improved for Se-L. Low active pseudoselenoproteins might be synthesized in low-Se condition. The underlying mechanism needs to be further investigated.

Role of AURKA in the hypothalamus-pituitary-testicular axis in Tibetan sheep from Tianzhu.

The mitosis-associated protein aurora kinase A (AURKA) regulates the maturation of germ cells. We have previously reported using transcriptome analysis that AURKA is expressed in yak testes. Although Tibetan sheep possess an immense economic value, their reproductive rate is low. Herein, the expression and functions of AURKA in the hypothalamus-pituitary-testicular (HPT) axis in Tibetan sheep from Tianzhu were investigated. The cDNA sequence of sheep AURKA was cloned and bioinformatics techniques were used to predict its structure. Tissue expression of AURKA was determined by qPCR, immunoblotting, immunostaining, and immunohistochemistry. The AURKA coding sequence was found to be 1218 bp in length, encoding a 405-amino acid polypeptide chain. Furthermore, the highest sequence similarity of AURKA with the corresponding sequence in other species was seen in goat and cattle; the least degree of similarity was seen in the domestic cat. In addition, AURKA expression was elevated in the testes compared to that in the hypothalamus and pituitary (p < 0.01). Moreover, AURKA was mainly localized in the hypothalamic paraventricular nucleus (magnocellular), chromophobe cells of the pituitary, and spermatogenic cells of the testis. These results indicated that AURKA might participate in sheep reproductive regulation, thus providing a reference for the study of AURKA function in the reproductive process of Tibetan sheep from Tianzhu.

Addressing male sexual and reproductive health in the wake of COVID-19 outbreak.

PURPOSE: The COVID-19 pandemic, caused by the SARS-CoV-2, represents an unprecedented challenge for healthcare. COVID-19 features a state of hyperinflammation resulting in a "cytokine storm", which leads to severe complications, such as the development of micro-thrombosis and disseminated intravascular coagulation (DIC). Despite isolation measures, the number of affected patients is growing daily: as of June 12th, over 7.5 million cases have been confirmed worldwide, with more than 420,000 global deaths. Over 3.5 million patients have recovered from COVID-19; although this number is increasing by the day, great attention should be directed towards the possible long-term outcomes of the disease. Despite being a trivial matter for patients in intensive care units (ICUs), erectile dysfunction (ED) is a likely consequence of COVID-19 for survivors, and considering the high transmissibility of the infection and the higher contagion rates among elderly men, a worrying phenomenon for a large part of affected patients. METHODS: A literature research on the possible mechanisms involved in the development of ED in COVID-19 survivors was performed. RESULTS: Endothelial dysfunction, subclinical hypogonadism, psychological distress and impaired pulmonary hemodynamics all contribute to the potential onset of ED. Additionally, COVID-19 might exacerbate cardiovascular conditions; therefore, further increasing the risk of ED. Testicular function in COVID-19 patients requires careful investigation for the unclear association with testosterone deficiency and the possible consequences for reproductive health. Treatment with phosphodiesterase-5 (PDE5) inhibitors might be beneficial for both COVID-19 and ED. CONCLUSION: COVID-19 survivors might develop sexual and reproductive health issues. Andrological assessment and tailored treatments should be considered in the follow-up.

Topiramate: A novel protective agent against ischemia reperfusion-induced oxidative injury after testicular torsion/detorsion.

Testicular torsion is a common urologic emergency and one of the causes of genital injury in males. Hence, early diagnosis and treatment are necessary to prevent testicular damage and infertility. It has been proved that topiramate (TPM) a medication used to treat epilepsy and prevent migraines has anti-inflammatory and anti-oxidative effects. Therefore, this study was designed to determine the influence of TPM on ischemia/reperfusion injury following testicular torsion/detorsion (T/D). Thirty-six male Wistar rats were divided into three groups (n = 12 for each group) including sham operated, T/D + vehicle, T/D + TPM(100 mg/kg, 30 min before detorsion). Testicular torsion was induced for 1 h by rotating right testis 7200 in the clockwise direction. After 5 h of reperfusion the testis was removed and histological changes and biochemical markers such as superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and levels of malondialdehyde (MDA) and reduced glutathione (GSH) were evaluated. MDA level significantly increased and GSH level significantly decreased after T/D compared to the sham group (p < 0.001). Moreover, after inducing testicular T/D, GPx, CAT and SOD activity were decreased, whereas administration of TPM significantly increased GSH level and GPx, CAT and SOD activities and decreased MDA level in testis tissue as compared to T/D group. After induction of T/D, histopathological evaluations also revealed severe testicular damages which were improved by TPM administration. Our results indicate that TPM had an ameliorating impact on ischemia/reperfusion injury in the rat model of testicular T/D. This protective effect was most likely induced by anti-oxidative properties of this drug.

The role of miR-128-3p through MAPK14 activation in the apoptosis of GC2 spermatocyte cell line following heat stress.

BACKGROUND: MicroRNAs play a crucial role in the regulation of spermatogenesis. For example, miR-128-3p expression is known to decrease significantly after testicular hyperthermia, but the regulatory effect of this change on the spermatogenesis damage caused by heat stress remains unclear. OBJECTIVES: This study aimed to verify whether the target gene of miR-128-3p is MAPK14, which affects spermatogenic cell proliferation and apoptosis under testicular hyperthermia. MATERIALS AND METHODS: Mouse testis and GC2 spermatocyte cell line heat stress models were established. miR-128-3p expression before and after heat stress was analyzed by reverse transcription polymerase chain reaction. MAPK14 and p-MAPK14 expression was detected by Western blot, and cell apoptosis was analyzed by Annexin V-FITC/PI. Subsequently, miR-128-3p inhibitors and mimics were used to interfere with spermatocytes before and after heat stress, respectively, for correlation detection. RESULTS: Compared with the control group, the heat stress group showed decreased miR-128-3p expression, increased p-MAPK14 expression, and decreased cell proliferation activity. In the GC2-spd cell line in vitro, miR-128-3p inhibitors were found to upregulate p-MAPK14 expression, reduce cell proliferation activity, and increase apoptosis, consistent with the results obtained in the heat treatment alone. Furthermore, miR-128-3p mimics transfected in the GC2 cells after heat stress reduced p-MAPK14 expression, alleviated the decrease in cell proliferation, and decreased the apoptosis level. CONCLUSIONS: The downregulation of miR-128-3p expression plays an important role in spermatogenesis damages after testicular hyperthermia, which is probably attributable to the activation of the MAPK signaling pathway. Downregulated miR-128-3p expression induces the apoptosis and inhibits the proliferation of spermatogenic cells by promoting MAPK14 phosphorylation.

Potential mechanisms of SARS-CoV-2 action on male gonadal function and fertility: Current status and future prospects.

The novel coronavirus was recognised in December 2019 and caught humanity off guard. The virus employs the angiotensin-converting enzyme 2 (ACE2) receptor for entry into human cells. ACE2 is expressed on different organs, which is raising concern as to whether these organs can be infected by the virus or not. The testis appears to be an organ enriched with levels of ACE2, while the possible mechanisms of involvement of the male reproductive system by SARS-CoV-2 are not fully elucidated. The major focus of the present studies is on the short-term complications of the coronavirus and gains importance on studying the long-term effects, including the possible effects of the virus on the male reproductive system. The aim of this review was to provide new insights into different possible mechanisms of involvement of male gonads with SARS-CoV-2 including investigating the ACE2 axis in testis, hormonal alterations in patients with COVID-19, possible formation of anti-sperm antibodies (ASA) and subsequently immunological infertility as a complication of SARS-CoV-2 infection. Finally, we suggest measuring the sperm DNA fragmentation index (DFI) as a determiner of male fertility impairment in patients with COVID-19 along with other options such as sex-related hormones and semen analysis. Invasion of SARS-CoV-2 to the spermatogonia, Leydig cells and Sertoli cells can lead to sex hormonal alteration and impaired gonadal function. Once infected, changes in ACE2 signalling pathways followed by oxidative stress and inflammation could cause spermatogenesis failure, abnormal sperm motility, DNA fragmentation and male infertility.