Polarized epithelium-sperm co-culture system reveals stimulatory factors for the secretion of mouse epididymal quiescin sulfhydryl oxidase 1.

Spermatozoa acquire fertilization ability through post-translational modifications. These membrane surface alterations occur in various segments of the epididymis. Quiescin sulfhydryl oxidases, which catalyze thiol-oxidation reactions, are involved in disulfide bond formation, which is essential for sperm maturation, upon transition and migration in the epididymis. Using castration and azoospermia transgenic mouse models, in the present study, we showed that quiescin sulfhydryl oxidase 1 (QSOX1) protein expression and secretion are positively correlated with the presence of testosterone and sperm cells. A two-dimensional in vitro epithelium-sperm co-culture system provided further evidence in support of the notion that both testosterone and its dominant metabolite, 5α-dihydrotestosterone, promote epididymal QSOX1 secretion. We also demonstrated that immature caput spermatozoa, but not mature cauda sperm cells, exhibited great potential to stimulate QSOX1 secretion in vitro, suggesting that sperm maturation is a key regulatory factor for mouse epididymal QSOX1 secretion. Proteomic analysis identified 582 secretory proteins from the co-culture supernatant, of which 258 were sperm-specific and 154 were of epididymal epithelium-origin. Gene Ontology analysis indicated that these secreted proteins exhibit functions known to facilitate sperm membrane organization, cellular activity, and sperm-egg recognition. Taken together, our data demonstrated that testosterone and sperm maturation status are key regulators of mouse epididymal QSOX1 protein expression and secretion.

A mouse seminal vesicle-secreted lysozyme c-like protein modulates sperm capacitation.

Lysozyme (LYZ) c-like proteins are primarily present in the testis and epididymis of male reproductive tissues. Here, we report a novel member of the c-type LYZ family, the seminal vesicle-secreted LYZ c-like protein (SVLLP). Three forms of SVLLP were purified from mouse seminal vesicle secretions and characterized as glycoproteins with the same protein core but different N-linked glycans. SVLLP is structurally similar to c-type LYZ proteins. Only one of the 20 invariant residues was altered in the consensus sequence of c-type LYZs; however, the changed residue (N53S) is one of two essential catalytic residues. LYZ activity assays demonstrated that the three glycoforms of SVLLP lacked enzyme activity. SVLLP is primarily expressed in seminal vesicles. Immunohistochemistry revealed that it occurs in the luminal fluid and mucosal epithelium of the seminal vesicles. Testosterone is not the primary regulator for its expression in the seminal vesicle. SVLLP binds to sperm and suppresses bovine serum albumin-induced sperm capacitation, inhibits the acrosome reaction, and blocks sperm-oocyte interactions in vitro, suggesting that SVLLP is a sperm capacitation inhibitor.

Testosterone regulation on quiescin sulfhydryl oxidase 2 synthesis in the epididymis.

The epididymis is an androgen-responsive organ, whose structure and functions are modulated by the coordination between androgen and epididymal cues. Highly regulated molecular interaction within the epididymis is required to support viable sperm development necessary for subsequent fertilization. In the present study, we extended our earlier findings on a promising epididymal protein, quiescin sulfhydryl oxidase 2 (QSOX2), and demonstrated a positive correlation between testosterone and QSOX2 protein synthesis through the use of loss- and restore-of-function animal models. Moreover, based on transcriptomic analyses and 2D culture system, we determined that an additional polarized effect of glutamate is indispensable for the regulatory action of testosterone on QSOX2 synthesis. In conclusion, we propose noncanonical testosterone signaling supports epididymal QSOX2 protein synthesis, providing a novel perspective on the regulation of sperm maturation within the epididymis.

Identification of urine neutrophil gelatinase-associated lipocalin molecular forms and their association with different urinary diseases in cats.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL), a promising renal biomarker, can exists as a monomer, a dimer and/or in a NGAL/matrix metalloproteinase-9 (MMP-9) complex form when associated with different urinary diseases in humans and dogs. In this study, the presence of the various different molecular forms of NGAL in cat urine (uNGAL) was examined and whether these forms are correlated with different urinary diseases was explored. RESULTS: One hundred and fifty-nine urine samples from cats with various different diseases, including acute kidney injury (AKI, 22 cats), chronic kidney disease (CKD, 55 cats), pyuria (44 cats) and other non-renal and non-pyuria diseases (non-RP, 26 cats), as well as healthy animals (12 cats), were collected. The molecular forms of and concentrations of urinary NGAL in these cats were analyzed, and their uNGAL-to-creatinine ratio (UNCR) were determined. The cats with AKI had the highest UNCR (median: 2.92 × 10- 6), which was followed by pyuria (median: 1.43 × 10- 6) and CKD (median: 0.56 × 10- 6); all of the above were significantly higher than the healthy controls (median: 0.17 × 10- 6) (p < 0.05). Three different NGAL molecular forms as well as the MMP-9 monomer were able to be detected in the cat urine samples. Moreover, the cases where urine NGAL monomer were present also had significantly higher levels of BUN (median: 18.9 vs 9.6 mmol/L) and creatinine (327.1 vs 168 umol/L). The presence of dimeric NGAL was found to be associated with urinary tract infections. Most cats in the present study (126/159, 79.2%) and more than half of healthy cats (7/12, 58.3%) had detectable NGAL/MMP-9 complex present in their urine. CONCLUSIONS: The monomeric and dimeric molecular forms of uNGAL suggest upper and lower urinary tract origins of disease, respectively, whereas the presence of the uNGAL/MMP-9 complex is able to be detected in most cats, including seemingly healthy ones.

Development and comparison of enzyme-linked immunosorbent assays based on recombinant trimeric full-length and truncated spike proteins for detecting antibodies against porcine epidemic diarrhea virus.

BACKGROUND: Since 2010, outbreaks of genotype 2 (G2) porcine epidemic diarrhea virus (PEDV) have caused high mortality in neonatal piglets and have had devastating impacts on the swine industry in many countries. A reliable serological assay for evaluating the PEDV-specific humoral and mucosal immune response is important for disease survey, monitoring the efficacy of immunization, and designing strategies for the prevention and control of PED. Two PEDV spike (S) glycoprotein-based indirect enzyme-linked immunosorbent assays (ELISAs) were developed using G2b PEDV-Pintung 52 (PEDV-PT) trimeric full-length S and truncated S1-501 proteins derived from the human embryonic kidney (HEK)-293 cell expression system. The truncated S1-501 protein was selected from a superior expressed stable cell line. The sensitivity and specificity of these two ELISAs were compared to immunostaining of G2b PEDV-PT infected cells and to a commercial nucleocapsid (N)-based indirect ELISA kit using a panel of PEDV negative and hyperimmune sera. RESULTS: The commercial N-based ELISA exhibited a sensitivity of 37%, a specificity of 100%, and a fair agreement (kappa = 0.37) with the immunostaining result. In comparison, the full-length S-based ELISA showed a sensitivity of 97.8%, a specificity of 94%, and an almost perfect agreement (kappa = 0.90) with the immunostaining result. Interestingly, the S1-501-based ELISA had even higher sensitivity of 98.9% and specificity of 99.1%, and an almost perfect agreement (kappa = 0.97) with the immunostaining result. A fair agreement (kappa< 0.4) was seen between the commercial N-based ELISA and either of our S-based ELISAs. However, the results of the full-length S-based ELISA shared an almost perfect agreement (kappa = 0.92) with that of S1-501-based ELISA. CONCLUSIONS: Both full-length S-based and S1-501-based ELISAs exhibit high sensitivity and high specificity for detecting antibodies against PEDVs. Considering the high protein yield and cost-effectiveness, the S1-501-based ELISA could be used as a reliable, sensitive, specific, and economic serological test for PEDV.

Mouse quiescin sulfhydryl oxidases exhibit distinct epididymal luminal distribution with segment-specific sperm surface associations.

Sulfhydryl oxidation is part of the sperm maturation process essential for the acquisition of sperm fertilization competency and its structural stabilization; however, the specific sulfhydryl oxidases that fulfill these roles have yet to be identified. In this study, we investigate the potential involvement of one atypical thiol oxidase family called quiescin Q6/sulfhydryl oxidase (QSOX) using the mouse epididymis as our model system. With multidisciplinary approaches, we show that QSOX isoform 1 and 2 exhibit complementary distribution throughout the epididymal duct, but that each variant possesses distinct subcellular localization within the epididymal principal cells. While QSOX2 was exclusively present in the Golgi apparatus of the caput and corpus epididymis, QSOX1c, the most profusely express QSOX1 variant, was abundantly present in the cauda luminal fluids. Moreover, immunohistochemistry studies together with proteomic identification in isolated epididymosomes provided evidence substantiating the release of QSOX2, but not QSOX1c, via an apocrine secretory pathway. Furthermore, we demonstrate for the first time, distinct association of QSOX1c and QSOX2 with the sperm acrosome and implantation fossa, during different stages of their epididymal maturation. In conclusion, our study provides the first comprehensive comparisons between QSOX1 and QSOX2 in the mouse epididymis, revealing their distinct epididymal distribution, cellular localization, mechanisms of secretion and sperm membrane association. Together, these data suggest that QSOX1 and QSOX2 have discrete biological functions in male germ cell development.

Efficacy of heat-labile enterotoxin B subunit-adjuvanted parenteral porcine epidemic diarrhea virus trimeric spike subunit vaccine in piglets.

Devastating outbreaks of porcine epidemic diarrhea (PED) started in China in late 2010 and rapidly spread to North America and Asia causing severe diarrhea and high mortality in neonatal piglets, indicating that a new generation of vaccine against porcine epidemic diarrhea virus (PEDV) is urgently needed. In the present study, to mimic the native spike (S) glycoprotein, a stable cell line producing the trimeric ectodomain of S glycoprotein of the PEDV Pintung-52 (PEDV-PT) strain was successfully established by incorporating T4 bacteriophage foldon sequence of fibritin trimerization domains at the C-terminal end and replacing the signal peptide of S protein with the tissue plasminogen activator signal peptide sequence at the N terminal end. The trimeric structure, bio-reactivity to PEDV-specific antibodies, and the N-glycosylation level of the recombinant S protein were characterized. To induce systemic and mucosal immunity, conventional 5-week-old piglets were immunized with the trimeric S glycoprotein combined with the B subunit of Escherichia coli heat-labile enterotoxin (LTB) by the intramuscular (IM) route. As compared with the control group, all piglets in the S protein-LTB immunized (IM PEDV S-LTB) group generated systemic PEDV S-specific IgG and neutralizing antibody in blood but a low level of fecal PEDV-specific IgA and limited protection against challenge of PEDV-PT strain. Our results suggest that the recombinant PEDV trimeric S glycoprotein could be a potential subunit vaccine candidate against PEDV, but IM immunization with LTB as the adjuvant provided insufficient protection. The development of a vaccine regimen for inducing mucosal immunity is an important task for generating a successful subunit vaccine against PEDVs.

The effects of type I collagenase on the degelification of chimpanzee (Pan troglodytes) semen plug and sperm quality.

BACKGROUND: Semen from the chimpanzee species becomes a colloidal solid after ejaculation. The formation of this copulatory plug is believed to prevent additional spermatozoa of subsequent mating events from accessing the ova. However, this naturally preserved strategy hampers the processes for sperm preparation. In this study, we investigated whether collagenase can be used to degelify the semen plug and accelerate the semen liquefaction process in zoo captive chimpanzee species (Pan troglodytes). RESULTS: We showed that incubation of chimpanzee ejaculates with 0.1% type I collagenase efficiently and significantly (p < 0.05) releases 2.7-fold more spermatozoa from the coagulated ejaculates, and this degelification process did not alter sperm morphology or viability; nor did it stimulate spontaneous capacitation or an acrosome reaction as assessed by tyrosine phosphorylation and peanut agglutinin stains; moreover, based on computer assisted sperm analysis assay, motility-related parameters remained similar to those of untreated spermatozoa. When collagenase effects were evaluated on cryopreserved sperm samples, we observed post collagenase treatment in which 2.5% glycerol, as a cryoprotectant, preserved sperm acrosome integrity better than 7.8%; however, 7.8% glycerol, as a cryoprotectant, maintained sperm motility better than that of 2.5% glycerol. CONCLUSIONS: Our results demonstrated for the first time that type I collagenase can be used to obtain a significantly higher number of spermatozoa from colloid chimpanzee semen ejaculate without affecting the physiological properties of spermatozoa, and these results are critical for the subsequent gamete development. Our results would benefit sperm preparation processes and cryopreservation efficiency per ejaculate, as more unaffected spermatozoa can be released from the semen plug within a shorter period of time. These results would also benefit the genetic diversity of the chimpanzee species, using sperm cells from less dominant individuals, and for achieving better pregnancy success in primates with significantly higher amounts of sperm for artificial insemination.

Determination of the cell tropism of serotype 1 feline infectious peritonitis virus using the spike affinity histochemistry in paraffin-embedded tissues.

Unlike for serotype II feline coronaviruses (FCoV II), the cellular receptor for serotype I FCoV (FCoV I), the most prevalent FCoV serotype, is unknown. To provide a platform for assessing the pattern by which FCoV I attaches to its host receptor(s), HEK293 cell lines that stably express the ectodomains of the spike (S) proteins derived from a FCoV I feline enteric coronavirus strain UU7 (FECV UU7) and a feline infectious peritonitis virus strain UU4 (FIPV UU4) were established. Using the recombinant S proteins as probes to perform S protein affinity histochemistry in paraffin-embedded tissues, although no tissue or enteric binding of FECV UU7 S protein was detected, it was found that by immunohistochemistry that the tissue distribution of FIPV UU4 S protein-bound cells correlated with that of FIPV antigen-positive cells and lesions associated with FIP and that the affinity binding of FIPV UU4 S protein on macrophages was not affected by enzymatic removal of host cell-surface sialic acid with neuraminidase. These findings suggest that a factor(s) other than sialic acid contribute(s) to the macrophage tropism of FIPV strain UU4. This approach allowed obtaining more information about both virus-host cell interactions and the biological characteristics of the unidentified cellular receptor for FCoV I.

Identification, characterization and purification of porcine Quiescin Q6-Sulfydryl Oxidase 2 protein.

BACKGROUND: Post-spermiogenesis membrane surface modifications rely on molecules present in the reproductive tracts. Two isoforms (isoform 1 and 2) from Quiescin Q6-Sulfydryl Oxidase protein family have been identified in the male reproductive tract of rodent species. However, unlike isoform 1, scarce information is available for isoform 2, likely due to its lower expression level and lack of proper purification methods to obtain sufficient protein quantity for further assays. RESULTS: This study demonstrated the presence of short and long forms of Quiescin Q6-Sulfydryl Oxidase 2 in boar, likely representing the secretory (short form) and transmembrane (long form) forms of Quiescin Q6-Sulfydryl Oxidase 2. Immunohistochemistry studies revealed the presence of Quiescin Q6-Sulfydryl Oxidase 2 in a broad range of porcine tissues; the pronounced vesicle-contained Quiescin Q6-Sulfydryl Oxidase 2 at the apical region of epididymis and seminal vesicles epithelium suggested its involvement in sperm physiology and its participation in semen formation. The majority of porcine Quiescin Q6-Sulfydryl Oxidase 2 could be purified via either antibody affinity column or be salted out using 10%-40% ammonium sulfate. Higher amount of low molecular weight Quiescin Q6-Sulfydryl Oxidase 2 observed in the seminal vesicle likely represents the secretory form of Quiescin Q6-Sulfydryl Oxidase 2 and reflects an exuberant secretory activity in this organ. CONCLUSIONS: We demonstrated for the first time, the presence of Quiescin Q6-Sulfydryl Oxidase 2 in porcine species; moreover, two forms of Quiescin Q6-Sulfydryl Oxidase 2 were identified and exhibited distinct molecular weights and properties during protein purification processes. This study also provided feasible Quiescin Q6-Sulfydryl Oxidase 2 purification methods from slaughterhouse materials that could potentially allow obtaining sufficient amount of Quiescin Q6-Sulfydryl Oxidase 2 for future functional investigations.

Roles of the reproductive tract in modifications of the sperm membrane surface.

Successful fertilization requires viable and functional spermatozoa to recognize and fuse with the oocyte. In most mammalian species, mature spermatozoa are not capable of fertilizing the oocytes immediately after ejaculation. However, unlike somatic cells, spermatozoa, after leaving the testis, are transcriptionally and translationally silent; therefore, upon completion of spermiogenesis, spermatozoa carry only a minimal amount of essential proteins on their membranes as well as within their restricted volume of cytoplasm. To develop into a fully functional and competent sperm that is capable of successful fertilization, modifications of the sperm membrane surface during its transit in the reproductive tracts is critical. These post-spermatogenesis modifications advance the maturation of epididymal spermatozoa. In addition, components secreted into the lumen of the reproductive tracts that are later added onto the sperm membrane surface also regulate (inhibit or activate) the functions of the spermatozoa. This acquisition of additional proteins from the reproductive tracts may compensate for the inactivity of morphologically mature spermatozoa. In this review, we discuss the contributions of the male and female genital tracts to modifications of the sperm membrane surface at different stages of fertilization.

Selective therapeutic efficacy of tyrosine kinase inhibitor sorafenib on the restoration of methylglyoxal-induced peritoneal fibrosis.

Peritoneal fibrosis, a common complication observed in long-term peritoneal dialysis patients, can gradually lead to ultrafiltration failure and the development of encapsulating peritoneal sclerosis. Although mechanisms of peritoneal fibrosis have been proposed, effective therapeutic options are unsatisfactory. Recently, several tyrosine kinase inhibitors have proven to be anti-fibrosis in rodent models. To assess the potential therapeutic effects of tyrosine kinase inhibitors on peritoneal fibrosis in the larger animal model, a novel porcine model of peritoneal fibrosis induced by 40 mM methylglyoxal in 2.5 % dialysate was established, and two different doses (20 mg/kg and 30 mg/kg) of sorafenib were given orally to evaluate their therapeutic efficacy in this study. Our results showed that sorafenib effectively reduced adhesions between peritoneal organs and significantly diminished the thickening of both the parietal and visceral peritoneum. Angiogenesis, vascular endothelial growth factor A production, myofibroblast infiltration, and decreased endothelial glycocalyx resulting from dialysate and methylglyoxal stimulations were also alleviated with sorafenib. However, therapeutic efficacy in ameliorating loss of mesothelial cells, restoring decreased ultrafiltration volume, and improving elevated small solutes transport rates was limited. In conclusion, this study demonstrated that sorafenib could potentially be used for peritoneal fibrosis treatment, but applying sorafenib alone might not be sufficient to fully rescue methylglyoxal-induced peritoneal defects.

Urinary angiotensin-converting enzyme 2 and its activity in cats with chronic kidney disease.

Introduction: Angiotensin-converting enzyme 2 (ACE2) played an important role in the renin-angiotensin-aldosterone system (RAAS) and it was proved to be renoprotective in renal disease. Urinary angiotensin-converting enzyme 2 (uACE2) has been shown to reflect renal injury in human and experimental studies, but its role in feline kidney disease remains unknown. Aims: Our objectives involve comparing uACE2 concentrations and activities in cats across CKD stages with healthy controls, investigating the relationship between uACE2 concentrations, activities, and clinicopathological data in feline CKD patients, and assessing the predictive abilities of both for CKD progression. Methods: A retrospective, case-control study. The concentration and activity of uACE2 were measured by commercial ELISA and fluorometric assay kits, respectively. The concentration was adjusted to give uACE2 concentration-to-creatinine ratios (UACCRs). Results: In total, 67 cats consisting of 24 control and 43 chronic kidney disease (CKD), including 24 early-stage CKD and 19 late-stage CKD, were enrolled in this study. UACCR values were significantly higher in both early-stage (2.100 [1.142-4.242] x 10-6) and late-stage feline CKD (4.343 [2.992-5.0.71] x 10-6) compared to healthy controls (0.894 [0.610-1.076] x 10-6; p < 0.001), and there was also significant difference between-early stage group and late-stage group (p = 0.026). Urinary ACE2 activity (UAA) was significantly lower in CKD cats (1.338 [0.644-2.755] x pmol/min/ml) compared to the healthy cats (7.989 [3.711-15.903] x pmol/min/ml; p < 0.001). UACCR demonstrated an independent, positive correlation with BUN (p < 0.001), and UAA exhibited an independent, negative correlation with plasma creatinine (p < 0.001). Both UACCR and UAA did not yield significant results in predicting CKD progression based on the ROC curve analysis. Conclusion and clinical importance: uACE2 concentration and activity exhibit varying changes as renal function declines, particularly in advanced CKD cats.

Cre-LoxP and tamoxifen-induced deletion of ovarian quiescin sulfhydryl oxidase 2 showed disruption of ovulatory activity in mice.

BACKGROUND: Quiescin sulfhydryl oxidase 2 (QSOX2) is a flavin adenine dinucleotide-dependent sulfhydryl oxidase that is known to be involved in protein folding, cell growth regulation, and redox state modification through oxidative activities. Earlier studies demonstrated the tissue and cellular localization of QSOX2 in the male reproductive tract, as well as the highly-regulated mechanism of QSOX2 protein synthesis and expression through the coordinated action of testosterone and epididymal-enriched amino acid, glutamate. However, the presence and the functions of QSOX2 in female reproduction are unknown. In this study, we applied the Cre-loxP gene manipulation system to generate the heterozygous and homozygous Qsox2 knockout mice and examined its effects on ovarian function. RESULTS: We demonstrated that QSOX2 was detected in the follicle-supporting cells (granulosa and cumulus cells) of ovarian follicles of all stages but was absent in the corpus luteum, suggesting its supportive role in folliculogenesis. In comparison with reproductive organogenesis in wild-type mice, there was no difference in testicular and epididymal structure in male Qsox2 knockout; however, Qsox2 knockout disrupted the regular ovulation process in female mice as a drastic decrease in the formation of the corpus luteum was detected, and no pregnancy was achieved when mating males with homozygous Qsox2 knockout females. RNAseq analyses further revealed that Qsox2 knockout altered critical signaling pathways and genes that are responsible for maintaining ovarian functions. CONCLUSION: Our data demonstrated for the first time that Qsox2 is critical for ovarian function in mice.

L1cam alternative shorter transcripts encoding the extracellular domains were overexpressed in the intestine of L1cam knockdown mice.

Hirschsprung disease (HSCR) is a congenital disorder of functional bowel obstruction due to the absence of enteric ganglia in distal bowel. Different L1cam variants were reportedly associated with L1cam syndrome and HSCR, whose phenotypes lacked predictable relevance to their genotypes. Using next-generation sequencing (NGS), we found an L1CAM de novo frameshift mutation in a female with mild hydrocephalus and skip-type HSCR. A nearly identical L1cam variant was introduced into FVB/NJ mice via the CRISPR-EZ method. A silent mutation was created via ssODN to gain an artificial Ncol restriction enzyme site for easier genotyping. Six L1cam protein-coding alternative transcripts were quantitatively measured. Immunofluorescence staining with polyclonal and monoclonal L1cam antibodies was used to characterize L1cam isoform proteins in enteric ganglia. Fifteen mice, seven males and eight females, generated via CRISPR-EZ, were confirmed to carry the L1cam frameshift variant, resulting in a premature stop codon. There was no prominent hydrocephalus nor HSCR-like presentation in these mice, but male infertility was noticed after observation for three generations in a total of 176 mice. Full-length L1cam transcripts were detected at a very low level in the intestinal tissues and almost none in the brain of these mice. Alternative shorter transcripts encoding the extracellular domains were overexpressed in the intestine of L1cam knockdown mice. Immunofluorescence confirmed no fulllength L1cam protein in enteric ganglia. These shorter L1cam isoform proteins might play a role in protecting L1cam knockdown mice from HSCR.

Antioxidant Nanoparticles Restore Cisplatin-Induced Male Fertility Defects by Promoting MDC1-53bp1-Associated Non-Homologous DNA Repair Mechanism and Sperm Intracellular Calcium Influx.

Introduction: Cisplatin, a commonly used anticancer compound, exhibits severe off-target organ toxicity. Due to its wide application in cancer treatment, the reduction of its damage to normal tissue is an imminent clinical need. Cisplatin-induced testicular oxidative stress and damage lead to male sub- or infertility. Despite earlier studies showing that the natural polyphenol extracts honokiol serve as the free radical scavenger that reduces the accumulation of intracellular free radicals, whether honokiol exhibits direct effects on the testis and sperm is unclear. Thus, the aim of the current study is to investigate the direct effects of honokiol on testicular recovery and sperm physiology. Methods: We encapsulated this polyphenol antioxidation compound into liposome-based nanoparticles (nHNK) and gave intraperitoneally to mice at a dosage of 5 mg/kg body mass every other day for consecutive 6 weeks. Results: We showed that nHNK promotes MDC1-53bp1-associated non-homologous DNA double-strand break repair signaling pathway that minimizes cisplatin-induced DNA damage. This positive effect restores spermatogenesis and allows the restructuring of the multi-spermatogenic layers in the testis. By reducing mitochondrial oxidative damage, nHNK also protects sperm mitochondrial structure and maintains both testicular and sperm ATP production. By a yet-to-identify mechanism, nHNK restores sperm calcium influx at the sperm midpiece and tail, which is essential for sperm hypermotility and their interaction with the oocyte. Discussion: Taken together, the nanoparticulated antioxidant counteracts cisplatin-induced male fertility defects and benefits patients undertaking cisplatin-based chemotherapy. These data may allow the reintroduction of cisplatin for systemic applications in patients at clinics with reduced testicular toxicity.

Oxidative Stress-Induced Alterations of Cellular Localization and Expression of Aquaporin 1 Lead to Defected Water Transport upon Peritoneal Fibrosis.

Being one of the renal replacement therapies, peritoneal dialysis (PD) maintains around 15% of end-stage kidney disease patients' lives; however, complications such as peritoneal fibrosis and ultrafiltration failure during long-term PD compromise its application. Previously, we established a sodium hypochlorite (NaClO)-induced peritoneal fibrosis porcine model, which helped to bridge the rodent model toward pre-clinical human peritoneal fibrosis research. In this study, the peritoneal equilibration test (PET) was established to evaluate instant functional changes in the peritoneum in the pig model. Similar to observations from long-term PD patients, increasing small solutes transport and loss of sodium sieving were observed. Mechanistic investigation from both in vivo and in vitro data suggested that disruption of cytoskeleton induced by excessive reactive oxygen species defected intracellular transport of aquaporin 1, this likely resulted in the disappearance of sodium sieving upon PET. Functional interference of aquaporin 1 on free water transport would result in PD failure in patients.

Preparation of the cortical reaction: maturation-dependent migration of SNARE proteins, clathrin, and complexin to the porcine oocyte's surface blocks membrane traffic until fertilization.

The cortical reaction is a calcium-dependent exocytotic process in which the content of secretory granules is released into the perivitellin space immediately after fertilization, which serves to prevent polyspermic fertilization. In this study, we investigated the involvement and the organization of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins in the docking and fusion of the cortical granule membrane with the oolemma in porcine oocytes. During meiotic maturation, secretory vesicles that were labeled with a granule-specific binding lectin, peanut agglutinin (PNA), migrated toward the oocyte's surface. This surface-orientated redistribution behavior was also observed for the oocyte-specific SNARE proteins SNAP23 and VAMP1 that colocalized with the PNA-labeled structures in the cortex area just under the oolemma and with the exclusive localization area of complexin (a trans-SNARE complex-stabilizing protein). The coming together of these proteins serves to prevent the spontaneous secretion of the docked cortical granules and to prepare the oocyte's surface for the cortical reaction, which should probably be immediately compensated for by a clathrin-mediated endocytosis. In vitro fertilization resulted in the secretion of the cortical granule content and the concomitant release of complexin and clathrin into the oocyte's cytosol, and this is considered to stimulate the observed endocytosis of SNARE-containing membrane vesicles.

Secretory mouse quiescin sulfhydryl oxidase 1 aggregates defected human and mouse spermatozoa in vitro and in vivo.

A flavin-dependent enzyme quiescin Q6 sulfhydryl oxidase 1 (QSOX1) catalyzes the oxidation of thiol groups into disulfide bonds. QSOX1 is prominently expressed in the seminal plasma. However, its role in male reproduction is elusive. Here, we purified the secreted form of QSOX1, i.e., QSOX1c, from mouse seminal vesicle secretions and revealed for the first time its function involved in sperm physiology. Exogenous addition of QSOX1c time-dependently promoted the in vitro aggregation of thiol-rich, oxidative stressed, and apoptotic mouse and human sperm cells. Also, in vivo aggregated sperm cells collected from mouse uterine and human ejaculates also showed high levels of QSOX1c, intracellular reactive oxygen species, annexin V, and free thiols. In summary, our studies demonstrated that QSOX1c could agglutinate spermatozoa susceptible to free radical attack and apoptosis. This characteristic may provide an opportunity to separate defective sperm cells and improve sperm quality before artificial insemination in humans and animals.

Counteracting Cisplatin-Induced Testicular Damages by Natural Polyphenol Constituent Honokiol.

Cisplatin, despite its anti-cancer ability, exhibits severe testicular toxicities when applied systemically. Due to its wide application in cancer treatment, reduction of its damages to normal tissue is an imminent clinical need. Here we evaluated the effects of honokiol, a natural lipophilic polyphenol compound, on cisplatin-induced testicular injury. We showed in-vitro and in-vivo that nanosome-encapsulated honokiol attenuated cisplatin-induced DNA oxidative stress by suppressing intracellular reactive oxygen species production and elevating gene expressions of mitochondrial antioxidation enzymes. Nanosome honokiol also mitigated endoplasmic reticulum stress through down regulation of Bip-ATF4-CHOP signaling pathway. Additionally, this natural polyphenol compound diminished cisplatin-induced DNA breaks and cellular apoptosis. The reduced type I collagen accumulation in the testis likely attributed from inhibition of TGFß1, αSMA and ER protein TXNDC5 protein expression. The combinatorial beneficial effects better preserve spermatogenic layers and facilitate repopulation of sperm cells. Our study renders opportunity for re-introducing cisplatin to systemic anti-cancer therapy with reduced testicular toxicity and restored fertility.