Shasha Zou

Derivation of male germ cells from induced pluripotent stem cells in vitro and in reconstituted seminiferous tubules.

Previous studies have demonstrated that mouse‐ and human‐induced pluripotent stem (iPS) cells can differentiate into primordial germ cells in vitro. However, up to now it is not known whether iPS cells would be able to differentiate into male germ cells in vivo. The aim of this study was to explore differentiation potential of iPS cells to male germ cells in vitro and in vivo.

Mesenchymal stem cells overexpressing Ihh promote bone repair

BackgroundIndian hedgehog (Ihh) signaling pathway is known to play key roles in various aspects of normal endochondral bone development. This study tested the potential roles of high Ihh signaling in the context of injury-induced bone regeneration.MethodsA rabbit tibia defect model was established to test the effects of the implant of Ihh/mesenchymal stem cells (MSCs)/scaffold complex. Computed tomography (CT), gross observation, and standard histological and immunohistological techniques were used to evaluate the effectiveness of the treatment. In vitro studies with MSCs and C3H10T1/2 cells were also employed to further understand the cellular and molecular mechanisms.ResultsWe found that the implanted Ihh/MSCs/scaffold complex promoted bone repair. Consistently, in vitro study found that Ihh induced the upregulation of chondrocytic, osteogenic, and vascular cell markers, both in C3H10T1/2 cells and MSCs.ConclusionsOur study has demonstrated that high Ihh signaling in a complex with MSCs enhanced bone regeneration effectively in a clinically relevant acute injury model. Even though the exact underlying mechanisms are still far from clear, our primary data suggested that enhanced chondrogenesis, osteogenesis, and angiogenesis of MSCs at least partially contribute to the process. This study not only has implications for basic research of MSCs and Ihh signaling pathway but also points to the possibility of direct application of this specific paradigm to clinical bone repair.

Endothelial Nitric Oxide Synthase (eNOS) T-786C, 4a4b, and G894T Polymorphisms and Male Infertility: Study for Idiopathic Asthenozoospermia and Meta-Analysis

ABSTRACT Recent studies on the eNOS gene and male infertility show that expression of eNOS regulates normal spermatogenesis in the testis, and the eNOS gene variants (T-786C, 4a4b, and G894T) are potentially involved in impairment of spermatogenesis and sperm function. Thus, we conducted this association and meta-analysis study to further validate whether variants of those three loci affected the risk of idiopathic asthenozoospermia (AZS) and male infertility. Approximately 340 Chinese idiopathic AZS patients and 342 healthy men were included for this case-control study, genotyped by gel electrophoresis analysis or direct sequencing of PCR products. The eNOS mRNA isolated from the semen of patients was further examined by quantitative real-time PCR. Also, a meta-analysis of association between eNOS gene polymorphisms and male infertility was performed. A significant association was identified on allelic level between 4a4b variant and AZS in our study (chi-squared = 7.53, corrected P = 0.018, odds ratio (OR) = 1.808), while there were no significant difference of T-786C and G894T for asthenozoospermia in both genotype and allele distributions. In addition, expression of eNOS was up-regulated in patients compared with controls (about 2.4-fold, P < 0.001). Furthermore, the results of the meta-analysis support the conclusion that the T-786C and 4a4b loci were associated with male infertility in both Asian and Caucasian populations. Our study provides genetic evidence for the eNOS gene being a risk factor for idiopathic AZS and male infertility. Considering genetic differences among populations and complex pathogenesis of male infertility, more validating studies using independent samples are suggested in the future.

Association Study Between Polymorphisms of PRMT6, PEX10, SOX5, and Nonobstructive Azoospermia in the Han Chinese Population

ABSTRACT A previous genomewide association study of nonobstructive azoospermia (NOA) in the Han Chinese population identified three risk loci (rs12097821, rs2477686, and rs10842262) and provided strong evidence for a genetic influence in male infertility. However, recently, a follow-up study of these single nucleotide polymorphism (SNP) loci in the Japanese population showed that none of them were significantly associated with NOA. Therefore, we conducted an association study, consisting of 550 NOA cases and 555 normal controls, to further validate whether the risk of those three SNPs still existed in an independent Han Chinese male population. The association studies did not support the association of rs12097821 and rs2477686 with NOA for both genotype and allele distributions, but rs10842262 in the SOX5 gene was significantly associated with NOA (chi square = 9.31; P = 0.0095 and chi square = 9.27; P = 0.0023, respectively). Our study provides genetic evidence for SOX5 polymorphism in NOA, contributing to predicting males at high risk of NOA in Han Chinese population. Considering genetic differences among populations, future validating studies in independent samples are suggested.

VEGF/VEGFR2 Signaling Regulates Germ Cell Proliferation in vitro and Promotes Mouse Testicular Regeneration in vivo

Vascular endothelial growth factor (VEGF) plays fundamental roles in testicular development; however, its function on testicular regeneration remains unknown. The objective of this study was to explore the roles VEGF/VEGFR2 signaling plays in mouse germ cells and in mouse testicular regeneration. VEGF and the VEGFR2 antagonist SU5416 were added to culture medium to evaluate their effects on spermatogonial stem cell line (C18-4 cells) proliferation. Testicular cells obtained from newborn male ICR mice were grafted into the dorsal region of male BALB/c nude mice. VEGF and SU5416 were injected into the graft sites to assess the effects of the VEGF and VEGFR2 signaling pathways on testicular reconstitution. The grafts were analyzed after 8 weeks. We found that VEGF promoted C18-4 proliferation in vitro, indicating its role in germ cell survival. HE staining revealed that seminiferous tubules were reconstituted and male germ cells from spermatogonia to spermatids could be observed in testis-like tissues 8 weeks after grafting. A few advantaged male germ cells, including spermatocytes and spermatids, were found in SU5416-treated grafts. Moreover, VEGF enhanced the expression of genes specific for male germ cells and vascularization in 8-week grafts, whereas SU5416 decreased the expression of these genes. SU5416-treated grafts had a lower expression of MVH and CD31, indicating that blockade of VEGF/VEGFR2 signaling reduces the efficiency of seminiferous tubule reconstitution. Collectively, these data suggest that VEGF/VEGFR2 signaling regulates germ cell proliferation and promotes testicular regeneration via direct action on germ cells and the enhancement of vascularization.

Ectopic expression of Sonic Hedgehog in a cryptorchid man with azoospermia: a case report.

A 30-year-old man presented with a left undescended testis, right testicular deficiency and azoospermia. Testicular biopsy revealed an absence of spermatocytes and increased numbers of Leydig cells in the undescended testis. Additional comparative analyses were undertaken to explore Sonic Hedgehog (Shh) immunostaining in the testis of juvenile and adult mice, in the testis of the patient with cryptorchidism, and in archival testicular tissue from a patient with obstructive azoospermia and a patient with prostate cancer. Shh immunostaining was demonstrated in spermatocytes in juvenile and adult mouse testis and in the patients with obstructive azoospermia and prostate cancer, suggesting that Shh signalling is involved in normal spermatogenesis. In the patient with cryptorchidism, Shh immunostaining was localized to the Leydig cells, which suggests that Shh might be involved in the abnormal expansion of the Leydig cell population in the testis. These preliminary data on the appearance of Shh protein during normal spermatogenesis might provide the basis for further investigations to clarify the role of Shh signalling in spermatogenesis during normal and pathogenic testis development.

A novel micro-straw for cryopreservation of small number of human spermatozoon.

Cryopreservation of few spermatozoa is still a major challenge for male fertility preservation. This study reports use a new micro-straw (LSL straw) for freezing few spermatozoa for intracytoplasmic sperm injection (ICSI). Semen samples from 22 fertile donors were collected, and each semen sample was diluted and mixed with cryoprotectant in a ratio of 1:1, and then frozen using three different straws such as LSL straw (50-100 μl), traditional 0.25 ml and 0.5 ml straws. For freezing, all straws were fumigated with liquid nitrogen, with temperature directly reducing to −130-−140°C. Sperm concentration, progressive motility, morphology, acrosome integrity, and DNA fragmentation index were evaluated before and after freezing. After freezing-thawing, LSL straw group had significantly higher percentage of sperm motility than traditional 0.25 ml and 0.5 ml straw groups (38.5% vs 27.4% and 25.6%, P < 0.003). Sperm motility and acrosomal integrity after freezing-thawing were significantly lower than that of before freezing. However, there was no significant difference in morphology, acrosome, and DNA integrity between the three types of straws (P > 0.05). As LSL straws were thinner and hold very small volume, the freezing rate of LSL straw was obviously faster than 0.25 ml straw and 0.5 ml straws. In conclusion, LSL micro-straws may be useful to store few motile spermatozoa with good recovery of motility for patients undergoing ICSI treatment.

Association and meta-analysis of HLA and non-obstructive azoospermia in the Han Chinese population

The exact aetiology and pathogenesis of most non‐obstructive azoospermia (NOA) are still unknown. The previous two genomewide association studies (GWASs) have identified three different loci within the HLA region for NOA in the Han Chinese population, including rs3129878, rs498422 and rs7194. To further validate the risk of three GWAS‐linked loci for NOA, we conducted a case–control study of these three risk loci in an independent Han Chinese male population, with 603 NOA patients and 610 controls. Furthermore, we also performed a meta‐analysis of five studies on these three NOA‐risk loci. The case–control study strongly suggested a significant association between loci rs3129878, rs498422 and rs7194 and NOA (P = 6.75 × 10−21 (OR = 2.2586), P = 0.0060 (OR = 1.4013) and P = 0.0128 (OR = 1.2626) respectively). Our meta‐analyses also supported the susceptibility of these three risk loci to NOA (P < 0.01). The risk variants within the HLA region potentially have a strong effect on males at risk of NOA, and may serve as diagnostic markers for male infertility. However, considering genetic difference between different populations, future validating studies in larger independent samples and animal experiments are suggested.

AB200. Association of rs3129878 and rs498422in the HLA region with non-obstructive azoospermia in the Han Chinese population.

Objective The previous genome-wide association study (GWAS) of non-obstructive azoospermia (NOA) in the Han Chinese populations identified two NOA-risk loci (rs498422 and rs3129878) within the HLA region, and provided strong evidence for the genetic influence of male infertility. A further case-control study found that only rs3129878 remained to be significantly associated with NOA in the Japanese population. Therefore, we conducted the association study to further validate whether the risk of NOA caused by these two SNPs was still existed in an independent Han Chinese male population, consisting of 550 NOA cases and 555 normal controls. Design A case-control study of the NOA susceptibility genes within the HLA region associations. Materials and methods These two SNPs were analyzed in 550 NOA patients and 555 controls of Chinese origin using direct sequencing. Then, the genotype and allele distributions of them were further analyzed using the online software SHEsis (http://analysis.bio-x.cn). Results The association studies strongly supported the significant association ofrs498422 and rs3129878 with NOA for both genotype and allele distributions (P=0.047 and P=1.87×10, respectively). Conclusions In our replication study of Chinese samples, we provided genetic evidence for the contribution of these two NOA-risk SNPs within the HLA genes region in predicting males at high risk of NOA in Han Chinese population. Considering genetic differences among populations, future validating studies in independent samples are suggested.