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Context The swim bladder of the croceine croaker is believed to have a therapeutic effect on various diseases. However, there is no research about its effect on mammalian spermatogenesis. Objective We investigated the swim bladder peptides (SBPs) effect on busulfan-induced oligoasthenospermia in mice. Materials and methods We first extracted SBP from protein hydrolysate of the croceine croaker swim bladder, and then five groups of ICR male mice were randomly assigned: control, control + SBP 60 mg/kg, busulfan, busulfan + SBP 30 mg/kg and busulfan + SBP 60 mg/kg. Mice received bilateral intratesticular injections of busulfan to establish oligoasthenospermia model. After treatment with SBP for 4 weeks, testis and epididymis were collected from all mice for further analysis. Results After treatment with SBP 30–60 mg/kg for 4 weeks, epididymal sperm concentration and motility increased by 3.9–9.6- and 1.9–2.4-fold than those of oligoasthenospermia mice induced by busulfan. Meanwhile, histology showed that spermatogenic cells decreased, leading to increased lumen diameters and vacuolization in the busulfan group. These features were reversed by SBP treatment. RNA-sequencing analysis revealed that, compared with the busulfan group, Lin28b and Igf2bp1 expression related to germ cell proliferation, increased with a >1.5-fold change after SBP treatment. Additionally, PGK2 and Cfap69 mRNAs associated with sperm motility, also increased with a >1.5-fold change. Furthermore, these findings were validated by quantitative real-time PCR and Western blotting. Discussion and conclusions This is the first reported evidence for the therapeutic effect of SBP on oligoasthenospermia. SBP may be a promising drug for oligoasthenospermia in humans.

To assess the role of three testis-specific genes including ZPBP2, PGK2, and ACRV1 in the prediction of sperm retrieval result and quality of retrieved sperm by microdissection testicular sperm extraction (micro-TESE) in non-obstructive azoospermia (NOA) patients. This was a case-control study including 57 testicular samples of NOA patients including 32 patients with successful sperm retrieval (NOA+) and 25 patients with failed sperm retrieval (NOA-), and 9 samples of men with normal spermatogenesis in the testes as the positive control (OA). We investigated the expression of candidate genes by RT-qPCR and germ cell population patterns by DNA flow cytometry in testicular biopsy samples. The association between PGK2 expressions with the quality of retrieved spermatozoa was also evaluated. The RT-qPCR data revealed a significantly higher expression of ZPBP2 and PGK2 in the NOA+ in comparison to NOA- group (P = 0.002, and P = 0.002, respectively). Flow cytometry results revealed that the haploid cell percentage was significantly higher in NOA+ vs. NOA- group (P = 0.0001). In samples with a higher percentage of haploid cells, expression levels of ZPBP2 and PGK2 were higher (P = 0.001). The PGK2 expression was significantly associated with retrieved sperm quality (P = 0.01). Our results contribute to the search for the biomarkers for predicting the presence of testicular sperm and would be useful to avoid unnecessary multiple micro-TESE. Overall, the expression pattern of the ZPBP2 and PGK2 may be useful in predicting sperm recovery success and quality of retrieved sperm in NOA patients. [ABSTRACT FROM AUTHOR]

This study aimed to assess the role of testis-specific proteins, PGK2 and ACR, in the prediction of sperm retrieval results by microdissection testicular sperm extraction (micro-TESE) in men with non-obstructive azoospermia (NOA). This was a case-control study including 48 semen samples of NOA patients undergoing the micro-TESE procedure, 15 semen samples from normozoospermic men as the positive control, and 12 semen samples from obstructive azoospermia/post-vasectomy (OA/PV) as negative controls. We investigated the levels of PGK2 and ACR proteins by ELISA tests in seminal plasma samples. The ELISA results revealed a significantly higher concentration of PGK2 and ACR in the NOA patients with successful sperm retrieval (NOA+) in comparison to NOA patients with failed sperm retrieval (NOA-) group ( p  = 0.0001 in both cases). For the first time, the data from this study suggests that a seminal PGK2 concentration of 136.3 pg/ml and ACR concentration of 21.75 mIU/ml can be used as cut-off values for the prediction of micro-TESE outcomes in NOA patients. These findings may be useful to avoid unnecessary micro-TESE operations. Overall, the seminal levels of the PGK2 and ACR proteins may be useful in predicting sperm retrieval success by micro-TESE in NOA patients.

Study Question: Is there an association between the expression of phosphoglycerate kinase (PGK) 2 in spermatozoa and sperm quality in both elderly men and young asthenozoospermia patients?Summary Answer: Spermatozoa from elderly men and young asthenozoospermia patients show decreased expression of PGK2, which has a close positive relationship with sperm quality.What Is Known Already: PGK1 and PGK2 are involved in spermatogenesis and thought to be related to sperm motility. However, limited information is known about their temporal-spatial expression in human spermatogenesis and their relationship with sperm quality.Study Design, Size, Duration: This was a case-control study including 30 healthy young males (aged 28-31 years), 30 elderly men (aged 68-70 years), and 30 asthenozoospermic patients (aged 25-40 years, progressive motility <32%) who donated semen samples. Furthermore, young testes samples were obtained from five fathers (27-33 years old) who had died in car accidents, while aged testes samples were obtained from five elderly fathers (78-82 years old) who were prostate cancer patients.Participants/materials, Setting, Methods: Semen samples from young adults, elderly men and asthenozoospermic patients were prepared, and their parameters were assessed by Computer-Aided Sperm Analysis (CASA). Sperm proteins were extracted for western blot analysis. Immunohistochemistry was used to characterize the cellular localization of PGK1 and PGK2 in testes samples. Sperm immunofluorescence quantification experiments identified the differential expression of PGK1 and PGK2 in sperm from young adults, elderly men and asthenozoospermic patients. Antibodies against PGK1 and PGK2 were used to test their influence on sperm motility and penetration into viscous media. A modified Kremer test using methyl cellulose was adopted to assess sperm function via penetration into viscous media.Main Results and the Role Of Chance: Cellular localization analysis showed that PGK1 was mainly expressed in spermatogonia whereas PGK2 was mainly expressed in round spermatids. Expression levels of both PGKs were significantly decreased in the testis with ageing (P < 0.05). Western blot and immunofluorescence quantification showed markedly lower expression of PGK2 (P < 0.05) in sperm from elderly men or asthenozoospermic patients compared sperm from with healthy young men. Sperm functional analysis validated the close relationship between expression of PGK2 and sperm motility (staining percentage, r = 0.60, P < 0.05; intensity, r = 0.59, P < 0.05). Use of an anti-PGK2 antibody on sperm significantly decreased their ability to penetrate into a cervical mucus substitute (P < 0.05).Limitations, Reasons For Caution: Before any clinical applications using PGK2 to assess sperm quality can be developed, more cases should be used to evaluate this approach.Wider Implications Of the Findings: The study provides new insights into the role of PGKs in male reproduction. The results also indicate that PGK2 is a promising molecular candidate for the assessment of sperm quality and the screening of male contraceptive targets.Study Funding/competing Interests: This work was supported by grants from the National Natural Science Foundation of China (no. 81300533, 81370013 and 81000277) and Shandong Provincial Natural Science Foundation, China (ZR2013HQ002). The authors declare no competing financial interests. [ABSTRACT FROM AUTHOR]

Context: The swim bladder of the croceine croaker is believed to have a therapeutic effect on various diseases. However, there is no research about its effect on mammalian spermatogenesis., Objective: We investigated the swim bladder peptides (SBPs) effect on busulfan-induced oligoasthenospermia in mice., Materials and Methods: We first extracted SBP from protein hydrolysate of the croceine croaker swim bladder, and then five groups of ICR male mice were randomly assigned: control, control + SBP 60 mg/kg, busulfan, busulfan + SBP 30 mg/kg and busulfan + SBP 60 mg/kg. Mice received bilateral intratesticular injections of busulfan to establish oligoasthenospermia model. After treatment with SBP for 4 weeks, testis and epididymis were collected from all mice for further analysis., Results: After treatment with SBP 30-60 mg/kg for 4 weeks, epididymal sperm concentration and motility increased by 3.9-9.6- and 1.9-2.4-fold than those of oligoasthenospermia mice induced by busulfan. Meanwhile, histology showed that spermatogenic cells decreased, leading to increased lumen diameters and vacuolization in the busulfan group. These features were reversed by SBP treatment. RNA-sequencing analysis revealed that, compared with the busulfan group, Lin28b and Igf2bp1 expression related to germ cell proliferation, increased with a >1.5-fold change after SBP treatment. Additionally, PGK2 and Cfap69 mRNAs associated with sperm motility, also increased with a >1.5-fold change. Furthermore, these findings were validated by quantitative real-time PCR and Western blotting., Discussion and Conclusions: This is the first reported evidence for the therapeutic effect of SBP on oligoasthenospermia. SBP may be a promising drug for oligoasthenospermia in humans.

We isolated and characterized the highly polymorphic tetra-nucleotide microsatellite S0719 on SSC7q14-q15 adjacent to the porcine testis-specific phosphoglycerate kinase 2 ( PGK2 ) gene and assigned it to the USDA-MARC linkage map on SSC7 position 77.5 cM closely linked to markers SW859 (76.3 cM) and SWR2036 (79.0 cM). In a panel of 344 individuals representing 11 pig breeds (European, Chinese, and North American), a total of 32 alleles were observed, and the overall breeds' calculated PIC (polymorphism information content), H E (heterozygosity), and N E (effective allele number) were 0.94, 0.94, and 16.41. Breed-specific PIC and H E ranged from 0.66 to 0.87, whereas N E was as low as 2.95 and as high as 7.96. Considering the high allelic variation of S0719 within and among pig breeds (79% of the genotyped animals were heterozygous), the marker is useful for individual animal identification and parentage determination. Finally, S0719 is also a valuable STS marker for fine-mapping QTL on SSC7 as position 77.5 cM is located in 25 QTL intervals ( http://www.animalgenome.org/QTLdb/ ). [ABSTRACT FROM AUTHOR]

Cellular differentiation is mediated by differential gene expression. The cells of the testis are no exception. Indeed, recent studies based on microarray and expressed sequence tag analyses have revealed dynamic changes in gene expression during spermatogenesis. The autosomal phosphoglycerate kinase gene Pgk2 is an example of a gene that is tightly regulated during spermatogenesis, with transcription initiating in primary spermatocytes and ceasing in postmeiotic spermatids. Our studies show that this tissue-specific transcription is regulated at multiple levels, including binding of ubiquitous and testis-specific transcription factors, reconfiguration of nucleosomes, decondensation of chromatin, modifications of specific residues in histones, and demethylation of DNA. Our ability to isolate relatively pure populations of different spermatogenic cell types has allowed us to determine the order of these events that lead up to initiation of transcription of the Pgk2 gene. By examining similar parameters in transgenic mice carrying various portions of Pgk2 regulatory sequence, we have localized specific signals responsible for each of these regulatory events. Together these results demonstrate that activation of testis- specific transcription of the Pgk2 gene involves a multifaceted, ordered cascade of epigenetic events that potentiates this locus in preparation for the initiation of transcription. [ABSTRACT FROM AUTHOR]

Study Question: Is there an association between the expression of phosphoglycerate kinase (PGK) 2 in spermatozoa and sperm quality in both elderly men and young asthenozoospermia patients?, Summary Answer: Spermatozoa from elderly men and young asthenozoospermia patients show decreased expression of PGK2, which has a close positive relationship with sperm quality., What Is Known Already: PGK1 and PGK2 are involved in spermatogenesis and thought to be related to sperm motility. However, limited information is known about their temporal-spatial expression in human spermatogenesis and their relationship with sperm quality., Study Design, Size, Duration: This was a case-control study including 30 healthy young males (aged 28-31 years), 30 elderly men (aged 68-70 years), and 30 asthenozoospermic patients (aged 25-40 years, progressive motility <32%) who donated semen samples. Furthermore, young testes samples were obtained from five fathers (27-33 years old) who had died in car accidents, while aged testes samples were obtained from five elderly fathers (78-82 years old) who were prostate cancer patients., Participants/materials, Setting, Methods: Semen samples from young adults, elderly men and asthenozoospermic patients were prepared, and their parameters were assessed by Computer-Aided Sperm Analysis (CASA). Sperm proteins were extracted for western blot analysis. Immunohistochemistry was used to characterize the cellular localization of PGK1 and PGK2 in testes samples. Sperm immunofluorescence quantification experiments identified the differential expression of PGK1 and PGK2 in sperm from young adults, elderly men and asthenozoospermic patients. Antibodies against PGK1 and PGK2 were used to test their influence on sperm motility and penetration into viscous media. A modified Kremer test using methyl cellulose was adopted to assess sperm function via penetration into viscous media., Main Results and the Role of Chance: Cellular localization analysis showed that PGK1 was mainly expressed in spermatogonia whereas PGK2 was mainly expressed in round spermatids. Expression levels of both PGKs were significantly decreased in the testis with ageing (P < 0.05). Western blot and immunofluorescence quantification showed markedly lower expression of PGK2 (P < 0.05) in sperm from elderly men or asthenozoospermic patients compared sperm from with healthy young men. Sperm functional analysis validated the close relationship between expression of PGK2 and sperm motility (staining percentage, r = 0.60, P < 0.05; intensity, r = 0.59, P < 0.05). Use of an anti-PGK2 antibody on sperm significantly decreased their ability to penetrate into a cervical mucus substitute (P < 0.05)., Limitations, Reasons for Caution: Before any clinical applications using PGK2 to assess sperm quality can be developed, more cases should be used to evaluate this approach., Wider Implications of the Findings: The study provides new insights into the role of PGKs in male reproduction. The results also indicate that PGK2 is a promising molecular candidate for the assessment of sperm quality and the screening of male contraceptive targets., Study Funding/competing Interests: This work was supported by grants from the National Natural Science Foundation of China (no. 81300533, 81370013 and 81000277) and Shandong Provincial Natural Science Foundation, China (ZR2013HQ002). The authors declare no competing financial interests., (© The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)