Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins

The GgcxK325Q Mutation Does Not Affect the Calcium Homeostasis of the Epididymis and Male Fertility in Mice

A low-calcium microenvironment is imperative for spermatozoa maturation within the epididymis. Our previous work has shown that γ-glutamyl carboxylase (GGCX), the carboxylation enzyme of the matrix Gla protein (MGP), plays an essential role in epididymal calcium homeostasis and sperm maturation in rats and that the GGCX SNP mutation rs699664 was associated with asthenozoospermia (AZS) in humans. Here, we investigated the expression patterns of GGCX and MGP in the mouse epididymis and generated GgcxK325Q knock-in (KI) mice. We also tested the effects of this mutation on epididymal calcium homeostasis, sperm function, and male fertility in GgcxK325Q-/- mice. The results showed that both GGCX and MGP were enriched in all regions of the mouse epididymis, especially in the initial segment of the epididymis. Double immunofluorescence staining revealed that GGCX colocalized with MGP in the epithelial cells of the initial segment and caput regions as well as in the lumen of the corpus and cauda regions of the mouse epididymis. However, the GgcxK325Q-/- mice were fertile with normal epididymal morphology, sperm functions, and epididymal calcium concentration. Overall, our findings revealed that the GgcxK325Q mutation does not exert any discernible effect on male fertility in mice.

Identification of testis development-related genes by combining Iso-Seq and RNA-Seq in Zeugodacus tau

Introduction: Zeugodacus tau (Walker) is an invasive pest. An effective method to control this pest is the sterile insect technique (SIT). To better apply this technique, it is necessary to understand testis development progression. Methods: Differentially expressed genes (DEGs) during testis development were analyzed by PacBio Iso-Seq and RNA-seq. Results: RNA-Seq library of Z. tau testes on day 1, 6, and 11 post eclosion were constructed. We identified 755 and 865 differentially expressed genes in the comparisons of T6 (testes on day 6) vs. T1 and T11 vs. T1, respectively. The KEGG pathway analysis showed that the DEGs were significantly enriched in retinol metabolism, vitamin B6 metabolism, and ascorbate and aldarate metabolism pathways. Knockdown of retinol dehydrogenase 12-like (rdh12-like), pyridoxal kinase (pdxk) and regucalcin (rgn), the representative gene in each of the above 3 pathways, reduced the hatching rate of Z. tau offspring. In addition, we identified 107 Drosophila spermatogenesis-related orthologous genes in Z. tau, of which innexin 2 (inx2) exhibited significantly up-regulated expression throughout testis development, and the knockdown of this gene reduced offspring hatching rate. Discussion: Our data indicated that rdh12-like, pdxk, rgn, and inx2 genes were related to testis development, and they were conserved in tephritid species. These results suggested that this gene might have the same function in tephritid. The findings provide an insight into testis development and spermatogenesis in tephritid species.

Metastasis-associated protein 1 participates in regulating luminal acidification of the epididymis via repressing estrogen receptor alpha transcription

BACKGROUND

As a component of the nucleosome remodeling and deacetylating (NuRD) complex, metastasis-associated protein 1 (MTA1) has been reported to be abundant in male reproductive system and might participate in spermatogenesis and sperm maturation, whereas the precise functional role of MTA1 in these processes is still undetermined.

OBJECTIVE

To investigate the effect and potential function of MTA1 in male fertility.

MATERIALS AND METHODS

Mta1 knockout mice (Mta1-/- ) were employed to detect their reproductive phenotype. The pH value of Mta1-/- epididymal luminal fluid was measured, and the potential mechanism of MTA1 involved in regulating luminal acidification was detected in vivo and in vitro. A vasectomy model with abnormal pH of epididymal lumen was established to further detect the effect of MTA1 on epididymal luminal microenvironment.

RESULTS

Mta1-/- mice were fertile without any detectable defects in spermatogenesis or sperm motility while the deficiency of MTA1 could acidify the initial segment of epididymis to a certain extent. MTA1 could interact with estrogen receptor alpha (ERα) and inhibit the transcription of ERα target gene, hydrogen exchanger 3 (NHE3), and ultimately affect the epididymal luminal milieu. After vasectomy, the Mta1-/- mice presented a more acidic epididymal lumen which was closer to the normal state compared to the wild-type model.

DISCUSSION AND CONCLUSION

MTA1 is dispensable for male fertility in mice, but plays a potentially important function in regulating luminal acidification of the epididymis.

Analysis of the Growth and Development of Children Born with ICSI of Epididymal and Testicular Spermatozoa: A Propensity Matching Study

OBJECTIVE

The study aimed to evaluate whether singleton live births (at 0, 1, 6, 12, and 24 months) following intracytoplasmic sperm injection (ICSI) using sperm of different origins (ejaculated or non-ejaculated sperm) are associated with the growth and development of children born.

METHODS

This was a retrospective cohort study conducted at a single center from January 2016 to December 2019. Follow-up data of the children were obtained from the Jiangsu Province Maternal and Child database. A total of 350 singleton live births after fresh embryo transfer (ET) with ICSI were included. Based on the origin of the sperm, the patients were divided into two groups: the ejaculated group (n = 310) and the non-ejaculated group (n = 40). Propensity score matching was used to control for multiple baseline covariates, resulting in 80 singleton live births (ejaculated sperm) matched to 40 singleton live births (non-ejaculated). The non-ejaculated group was further divided into two subgroups: the PESA group (n = 23) and the TESA group (n = 17). The primary outcome of the study was the growth and development of children. Secondary outcomes included the 2PN rate, high-cleavage embryo rate, blastocyst formation rate, and others.

RESULTS

After matching parental age, BMI, occupation, and maternal serum AMH level, there was no significant difference found in the growth and development of children between the non-ejaculated and ejaculated group or the PESA group and TESA group, respectively. However, the 2PN rate and the blastocyst formation rate were higher in the ejaculated group compared to the non-ejaculated group (91.02 and 85.45, P = 0.002) and (67.37 and 56.06, P = 0.019), respectively. The high-quality cleavage embryo rate was also higher in the TESA group compared to the PESA group (85.06 and 65.63, P = 0.001).

CONCLUSION

This study suggests that there are no significant differences in the growth and development of children born following ICSI using sperm of different origins (ejaculated or non-ejaculated). For nonobstructive azoospermia (OA) patients, sperm derived from the testis may be more effective than derived from the epididymis. However, due to the limited sample size of the non-ejaculated group in this study, further investigations with larger sample sizes are needed to validate these findings.

Shenjing Guben Wan promotes sperm development by increasing the activity of seminiferous epithelium Sertoli cells

Background

Infertility is an important social problem. Asthenozoospermia (AZS) is a common pathological cause of male infertility, but its pathogenesis is unclear. Shenjing Guben Wan (SJGBW), a traditional Chinese medicine, has shown remarkable effects during the clinical treatment of oligozoospermia or AZS.

Methods

In this study, clinical evaluations were carried out on 184 AZS patients receiving SJGBW treatment, including sperm count, sperm quality, and pregnancy rate. Also, ornidazole was used to build an AZS mouse model, and SJGBW treatment was administered. The sperm quantity and fertility of mice in different groups were evaluated; a cholecystokinin octapeptide-8 (CCK-8) experiment was carried out to test the activity of seminiferous epithelium Sertoli cells, and immunohistochemistry and the Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick-End Labeling (TUNEL) method were employed to test the pathological information and expression of the Sertoli cell surface marker in the testicular tissues of mice in each group.

Results

The sperm vitality, progressive sperm motility, and sperm morphology of patients who received SJGBW treatment were all improved (P<0.05). In the AZS group, the average sperm count, sperm vitality, pregnancy rate, and female mouse litters were all lower relative to mice in the control group. Following SJGBW treatment, the average sperm count, sperm vitality, pregnancy rate, and female mouse litters of mice in the AZS group were all significantly improved. The cytobiological experimental results showed that compared with the serum of normal male mice in the control group, the drug serum containing SJGBW could improve the cell vitality and proliferative ability of seminiferous epithelium Sertoli cells in AZS mice. Furthermore, the TUNEL results showed that the seminiferous tubule Sertoli cells and mesenchymal cells of the AZS mice exhibited the most significant apoptosis, which was alleviated following SJGBW treatment. Moreover, the levels of Sertoli cell marker, SOX9, and anti-apoptosis protein, Bcl2, in SJGBW-treated mice were both higher than that in AZS mice.

Conclusions

SJGBW can promote the development and maturation of germ cells by facilitating the proliferation of Sertoli cells in AZS patients, thereby improving the fertility of these patients.

Epididymal epithelial degeneration and lipid metabolism impairment account for male infertility in occludin knockout mice

Occludin (OCLN) is a tight junction protein and Ocln deletion mutation causes male infertility in mice. However, the role of OCLN in male reproductive system remains unknown. In this study, we used an interdisciplinary approach to elucidate the underlying mechanism of male infertility in related to OCLN function, including Ocln knockout mice as well as a combined omics analysis and immunofluorescent labelling. Our results showed that the epididymis of Ocln-null mice displayed a phenomenon resembling epididymal sperm granuloma, which occurred especially in the junctional region between caput and corpus epididymidis. Sperm motility and fertilisation capacity were also impaired in these Ocln-null mice, accompanied by enlarged tubules in the proximal regions and degeneration in the distal regions of epididymis. Cellular localization analysis showed that OCLN immunofluorescence was enriched only in the apical junction of epithelial principal cells in the proximal regions of epididymis. Integrative omics analysis revealed the downregulation of gene clusters enriched in acid secretion and fatty acid metabolism in the Ocln-null epididymis, especially the enzymes related to the unsaturated arachidonic acid pathway. The number of proton-pump V-ATPase-expression clear cells, a key player of luminal acidification in the epididymis, declined drastically from prepubertal age before sperm arrival but not in the early postnatal age. This was accompanied by programmed cell death of clear cells and increased pH in the epididymal fluid of OCLN-deficient mice. The lipidomics results showed significantly increased levels of specific DAGs conjugated to unsaturated fatty acids in the Ocln-mutant. Immunofluorescent labelling showed that the arachidonic acid converting enzyme PTGDS and phospholipase PLA2g12a were prominently altered in the principal cells and luminal contents of the Ocln-mutant epididymis. Whereas the carboxylate ester lipase CES1, originally enriched in the WT basal cells, was found upregulated in the Ocln-mutant principal cells. Overall, this study demonstrates that OCLN is essential for maintaining caput-to-corpus epithelial integrity, survival of acid-secreting clear cells, and unsaturated fatty acid catabolism in the mouse epididymis, thereby ensuring sperm maturation and male fertility.