Spermatogonial Stem Cells Markers Research Articles

PD39-10 A XENO-FREE CULTURE METHOD FOR THE IN VITRO EXPANSION OF HUMAN SPERMATOGONIAL STEM CELLS

You have accessJournal of UrologyInfertility: Basic Research & Pathophysiology (PD39)1 Sep 2021PD39-10 A XENO-FREE CULTURE METHOD FOR THE IN VITRO EXPANSION OF HUMAN SPERMATOGONIAL STEM CELLS Meghan Robinson, Ryan Flannigan, and Luke Witherspoon Meghan RobinsonMeghan Robinson More articles by this author , Ryan FlanniganRyan Flannigan More articles by this author , and Luke WitherspoonLuke Witherspoon More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002049.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: In vitro expansion of spermatogonial stem cells (SSCs) has been established using animal-derived fetal bovine serum (FBS), however, animal components introduce the risk of contaminating with pathogens, making them unsuitable for medical use. This study set out to develop xeno-free culture conditions for the expansion of human SSCs. METHODS: SSCs were derived from human induced pluripotent stem cells (hiPSCs) and tested in various xeno-free media conditions in combination with growth factors Prostaglandin D2 (PDG2) and Insulin-Like Growth Factor 1 (IGF1). Primary SSCs then underwent 3 passages in the best condition, were cryopreserved and thawed, and then analysed for changes in gene and protein expression by real time polymerase chain reaction (RT-qPCR) and immunocytochemistry. RESULTS: 10 ng/mL PDG2 with 10 ng/mL IGF1 was found to replace FBS and BSA without loss of viability or growth. ROCK inhibitor Y-27632 was determined to be necessary for viability upon thawing. Compared to established conditions, the SSCs shared identical protein expression profiles for the SSC markers Glial Cell-Derived Neurotrophic Factor Family Receptor Alpha 1 (GFRA1), G-Protein Coupled Receptor 125 (GPR125), Thy-1 Cell Surface Antigen (CD90), and Stage-Specific Embryonic Antigen 4 (SSEA4) (Figure 1A-B). RT-qPCR analyses revealed no significant variation in gene expression of undifferentiated germ cell markers and Inhibitor Of Differentiation 4 (ID4), and Fibroblast Growth Factor Receptor 3 (FGFR3). The greatest change seen was an increase in Deleted In Azoospermia Like (DAZL), a regulator of both SSC proliferation and differentiation (23-fold) (Figure 1C). CONCLUSIONS: This study identified a combination of growth factors capable of replacing FBS and BSA components in established SSC expansion cell culture. This xeno-free defined formulation allows standardized SSC culture and removes the risk of animal pathogens. Source of Funding: VCHRI, CUASF, CIHR, UBC © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e671-e672 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Meghan Robinson More articles by this author Ryan Flannigan More articles by this author Luke Witherspoon More articles by this author Expand All Advertisement Loading ...

MicroRNA-30a-5p promotes differentiation in neonatal mouse spermatogonial stem cells (SSCs)

BackgroundThe importance of spermatogonial stem cells (SSCs) in spermatogenesis is crucial and intrinsic factors and extrinsic signals mediate fate decisions of SSCs. Among endogenous regulators, microRNAs (miRNAs) play critical role in spermatogenesis. However, the mechanisms which individual miRNAs regulate self- renewal and differentiation of SSCs are unknown. The aim of this study was to investigate effects of miRNA-30a-5p inhibitor on fate determinations of SSCs.MethodsSSCs were isolated from testes of neonate mice (3–6 days old) and their purities were performed by flow cytometry with ID4 and Thy1 markers. Cultured cells were transfected with miRNA- 30a-5p inhibitor. Evaluation of the proliferation (GFRA1, PLZF and ID4) and differentiation (C-Kit & STRA8) markers of SSCs were accomplished by immunocytochemistry and western blot 48 h after transfection.ResultsBased on the results of flow cytometry with ID4 and Thy1 markers, percentage of purity of SSCs was about 84.3 and 97.4 % respectively. It was found that expression of differentiation markers after transfection was significantly higher in miRNA-30a- 5p inhibitor group compared to other groups. The results of proliferation markers evaluation also showed decrease of GFRA1, PLZF and ID4 protein in SSCs transfected with miRNA-30a-5p inhibitor compared to the other groups.ConclusionsIt can be concluded that inhibition of miRNA-30a-5p by overexpression of differentiation markers promotes differentiation of Spermatogonial Stem Cells.

Effect of a Freezing Medium Containing Melatonin on Markers of Pre-meiotic and Post-meiotic Spermatogonial Stem Cells (SSCs) After Transplantation in an Azoospermia Mouse Model Due to Testicular Torsion.

Spermatogonial stem cells (SSCs) are essential to the initiation of spermatogenesis. Cryopreservation, long-term maintenance, and auto-transplantation of SSCs could be a new treatment for infertility. The aim of this study was to add melatonin to the basic freezing medium and to evaluate its effect on the efficiency of the thawed SSCs after transplantation into the testicles of azoospermic mice. SSCs were isolated from newborn NMRI mice, and the cells were enriched to assess morphological features. The thawed SSCs were evaluated for survival, apoptosis, and ROS level before transplantation, and the proliferation (MVH and ID4) and differentiation (c-Kit, SCP3, TP1, TP2, and Prm1) markers of SSCs were examined using immunofluorescence, western blot, and quantitative real-time polymerase chain reaction (PCR) after transplantation. It was found that the survival rate of SSCs after thawing was significantly higher in the melatonin group compared with the cryopreservation group containing basic freezing medium, and the rate of apoptosis and level of ROS production also decreased significantly in the cryopreservation group with melatonin (p < 0.05). The expression of proliferation and differentiation markers after transplantation was significantly higher in the cryopreservation group with melatonin compared to the cryopreservation group (p< 0.05). The results suggest that adding melatonin to the basic freezing medium can effectively protect the SSCs by increasing the viability and reducing the ROS production and apoptosis and improve the transplantation efficiency of SSCs after cryopreservation, which will provide a significant suggestion for fertility protection in the clinic.

Characterization, isolation, and culture of spermatogonial stem cells in Macaca fascicularis.

Spermatogonial stem cells (SSCs) have great applications in both reproductive and regenerative medicine. Primates including monkeys are very similar to humans with regard to physiology and pathology. Nevertheless, little is known about the isolation, the characteristics, and the culture of primate SSCs. This study was designed to identify, isolate, and culture monkey SSCs. Immunocytochemistry was used to identify markers for monkey SSCs. Glial cell line-derived neurotrophic factor family receptor alpha-1 (GFRA1)-enriched spermatogonia were isolated from monkeys, namely Macaca fascicularis (M. fascicularis), by two-step enzymatic digestion and magnetic-activated cell sorting, and they were cultured on precoated plates in the conditioned medium. Reverse transcription-polymerase chain reaction (RT-PCR), immunocytochemistry, and RNA sequencing were used to compare phenotype and transcriptomes in GFRA1-enriched spermatogonia between 0 day and 14 days of culture, and xenotransplantation was performed to evaluate the function of GFRA1-enriched spermatogonia. SSCs shared some phenotypes with rodent and human SSCs. GFRA1-enriched spermatogonia with high purity and viability were isolated from M. fascicularis testes. The freshly isolated cells expressed numerous markers for rodent SSCs, and they were cultured for 14 days. The expression of numerous SSC markers was maintained during the cultivation of GFRA1-enriched spermatogonia. RNA sequencing reflected a 97.3% similarity in global gene profiles between 0 day and 14 days of culture. The xenotransplantation assay indicated that the GFRA1-enriched spermatogonia formed colonies and proliferated in vivo in the recipient c-KitW/W (W) mutant mice. Collectively, GFRA1-enriched spermatogonia are monkey SSCs phenotypically both in vitro and in vivo. This study suggests that monkey might provide an alternative to human SSCs for basic research and application in human diseases.

The role of Rho-associated kinase inhibitor, Y-27632 on primary culture of ovine spermatogonial stem cells.

The access to sufficient numbers of spermatogonial stem cells (SSCs) is a prerequisite for the study of their regulation and further biomanipulation. Rho kinase (ROCK) belongs to a family of serine/threonine kinases and involves in a wide range of fundamental cellular functions. The aim of the present study was to study the effect of ROCK inhibitor, Y-27632 (0.1-40 µM), during the primary culture of ovine SSCs. SSCs were collected from 3-5-month-old’s lamb testes. The viability of SSCs, the apoptosis assay of SSCs, the intracellular reactive oxygen species (ROS) analysis, and the SSCs markers and apoptosis-related gene expressions were detected by MTT reduction assay, Annexin V–FITC/ Propidium Iodide (PI) dual staining, flow cytometry and real-time-PCR studies, respectively. Morphological analyses indicated that the 5-10 µM Y-27632 had an optimal effect on the number of presumptive SSCs colonies and the area covered by them after a 10 days culture. The cell viability, apoptosis and necrosis of SSCs after 10 days’ culture were not affected in comparison with the control group, and the 20 µM of Y-27632 resulted in significantly decreased cell viability (P<0.05) and an increased necrosis of cells. On day 10 after culture, the expression of P53 was decreased with an increase from 0 to 10 µM in the Y-27632 dose. In the 20 µM Y-27632 group, the expressions of P53 and Bax were higher and the Bcl-2 was lower than other groups and these values were significantly different from 5 and 10 µM Y-27632 groups (P<0.05). The level of intracellular ROS was decreased with an increase in the Y-27632 dose from 5 to 20 µM in comparison with the control group. In conclusion, the present study demonstrated that Y-27632 at a concentration of 5-10 µM provided optimal culture conditions for the primary culture of ovine SSCs.

Silk Nanofibrous Electrospun Scaffold Amplifies Proliferation and Stemness Profile of Mouse Spermatogonial Stem Cells

Electrospun nanofibrous scaffolds provide a structural microenvironment similar to the native extracellular matrix, which leads to the maintenance and propagation of the cultured cells under in vitro conditions. Furthermore, we used the sertoli cells to improve SSC proliferation due to its secretory role in growth factors. In this study, a silk electrospun nanofibrous scaffold has been used as a microenvironment for guiding the proliferation of spermatogonial stem cells (SSCs). SSCs were seeded on the prepared scaffolds and then cultured in vitro for 2 weeks. The attachment of SSCs was examined by scanning electron microscopy (SEM). Cell attachment and viability were evaluated via 4′, 6-diamidino-2-phenylindole staining and 3-(4, 5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide assessment, respectively. The expression of the specific SSC genes including stimulated by retinoic acid gene 8 (Stra8), deleted in azoospermia-like (DAZL) and piwil-like RNA-mediated gene silencing 2 (Piwil2), was quantified using real-time-PCR and confirmed by immunofluorescent staining. The data indicated that the prepared scaffold guided more effective SSC attachment and proliferation in comparison to the monolayer control. However, a significant upregulation of DAZL, Stra8, and piwill2 genes was observed in the cells grown on the silk scaffold. Also, the expression of Srta8 and Oct4 in the cultured cells was confirmed by immunofluorescence staining 2 weeks post-culture. Silk scaffold increases the in vitro viability of SSCs and amplifies their proliferation during the culture period. It is concluded that silk scaffold can serve as an appropriate substrate with broad implications for SSC proliferation under in vitro culture medium. We used a silk scaffold for guiding the proliferation of spermatogonial stem cell (SSC) population. Spermatogonia stem cells were seeded and cultured on silk scaffolds for 2 weeks. The attachment of SSCs was examined via SEM and viability was evaluated by DAPI staining and MTT assessments. The expression of specific spermatogonial stem cell markers including Stra8 gene, DAZL, and Piwill2 was quantified via Q-PCR and immunofluorescent staining. Scaffold guides firm attachment of SSCs and proliferates more than a monolayer layer. The significant upregulation of DAZL, Stra8, piwill2, and Oct4 in the experiment was confirmed by the real-time PCR and immunofluorescence staining 2 weeks after culture. Silk scaffold increases the in vitro viability of SSCs and amplifies their proliferation during the culture period. Silk scaffold can serve as an appropriate substrate with wide implications for SSC proliferation under in vitro condition.

Derivation and propagation of spermatogonial stem cells from human pluripotent cells

ObjectivesThis study is designed to generate and propagate human spermatogonial stem cells (SSCs) derived from human pluripotent stem cells (hPSCs).MethodshPSCs were differentiated into SSC-like cells (SSCLCs) by a three-step strategy. The biological characteristics of SSCLCs were detected by immunostaining with antibodies against SSC markers. The ability of self-renewal was measured by propagating for a long time and still maintaining SSCs morphological property. The differentiation potential of SSCLCs was determined by the generation of spermatocytes and haploid cells, which were identified by immunostaining and flow cytometry. The transcriptome analysis of SSCLCs was performed by RNA sequencing. The biological function of SSCLCs was assessed by xeno-transplantation into busulfan-treated mouse testes.ResultsSSCLCs were efficiently generated by a 3-step strategy. The SSCLCs displayed a grape-like morphology and expressed SSC markers. Moreover, SSCLCs could be propagated for approximately 4 months and still maintained their morphological properties. Furthermore, SSCLCs could differentiate into spermatocytes and haploid cells. In addition, SSCLCs displayed a similar gene expression pattern as human GPR125+ spermatogonia derived from human testicular tissues. And more, SSCLCs could survive and home at the base membrane of seminiferous tubules.ConclusionSSCLCs were successfully derived from hPSCs and propagated for a long time. The SSCLCs resembled their counterpart human GPR125+ spermatogonia, as evidenced by the grape-like morphology, transcriptome, homing, and functional characteristics. Therefore, hPSC-derived SSCLCs may provide a reliable cell source for studying human SSCs biological properties, disease modeling, and drug toxicity screening.

Stage-specific embryonic antigen 4 is a membrane marker for enrichment of porcine spermatogonial stem cells.

Spermatogonial stem cells (SSCs), as tissue-specific stem cells, are capable of both self-renewal and differentiation and supporting the continual and robust spermatogenesis for male fertility. As a rare sub-fraction of undifferentiated spermatogonia, SSCs share most molecular markers with the progenitor spermatogonia. Thus, the heterogeneity of the progenitor cells often obscures the characteristics of stem cells. Distinguishing SSCs from the progenitors is of paramount importance to understand the regulatory mechanisms governing their actions. The present study was designed to reveal that SSEA4 can be a marker for putative porcine SSCs that distinguished it from the progenitors and to build a sorting program for efficient enrichment of porcine SSCs. To explore expression of SSEA4 within the undifferentiated spermatogonial population, we performed co-immunofluorescent staining for SSEA4 and common molecular markers (VASA, DBA, PLZF, c-KIT, and SOX9) in the 7-, 90-, and 150-day-old porcine testicular tissues. SSEA4-positive cells were isolated from the 90-day-old porcine testes by flow cytometry. Immunofluorescent, RNA-sequencing, and transplantation analysis were used to reveal that SSEA4-positive fraction holds the stem cell capacity. We found that SSEA4 was expressed in a rare sub-fraction of porcine undifferentiated spermatogonia, and RNA-sequencing analysis revealed that the genes for stem cell maintenance and SSC-specific markers (ID4 and PAX7) were up-regulated in the SSEA4-sorted fraction, compared with undifferentiated spermatogonia. In addition, germ cell transplantation assay demonstrated that SSEA4-positive spermatogonia colonized in the recipient testicular tubules. Sorting of the undifferentiated spermatogonia with anti-SSEA4 antibody resulted in a 2.5-fold enrichment of SSCs compared with the germ cell gate group, and 21-fold enrichment of SSCs compared with the SSEA4-negative spermatogonia group. Our findings revealed that SSEA4 is a new surface marker for porcine undifferentiated spermatogonia. This finding helps to elucidate the characteristics of porcine SSCs and facilitates the culture and manipulation of SSCs.

EZH2 expression and its role in spermatogonial stem cell self-renewal in goats

Enhancer of zeste homolog 2 (EZH2) is a histone H3 lysine 27 (H3K27) methyltransferase that plays vital roles in mouse spermatogenesis. However, the expression pattern and role of EZH2 in goat spermatogonial stem cells (SSCs) is unknown. In the present study, we investigated EZH2 expression in the testis of postpubertal goats and its effect on the biological characteristics of goat SSCs. We found that EZH2 mRNA (P < 0.01) and protein (P < 0.05) expression was increased in the testes of postpubertal goats compared to that of prepubertal goats. Moreover, EZH2 was more highly expressed in goat SSCs than in Leydig cells (P < 0.01) and Sertoli cells (P < 0.01) as determined by qPCR, Western blot, and immunofluorescence. Compared to a negative control (NC), cell proliferation (P < 0.01) and viability (P < 0.01) were decreased in SSCs in which EZH2 was knocked down, and the G2/M phase of the cell cycle was blocked (P < 0.01), as determined by Edu staining, CCK-8 assay, and flow cytometry analysis. Additionally, the expression of CASP3, CASP9, and BAX was significantly increased (P < 0.01) while BCL2 expression was decreased (P < 0.01) in EZH2 knockdown SSCs. Notably, the expression of GDNF, a SSCs marker gene, and DAZL, a spermatogenesis-related gene, were significantly decreased (P < 0.01) while GFRA1 expression was significantly up-regulated (P < 0.01) in EZH2 knockdown SSCs. Our data suggest that EZH2 plays a pivotal role in the self-renewal of goat SSCs, and knockdown of EZH2 might impair spermatogenesis in goats.

Bcl2-Associated X (BAX) Knockout in Mice Resulted in Persistence of Neonatal Testicular Germ Cells (Gonocytes)

During early testicular development, neonatal gonocytes transform into spermatogonial stem cells (SSC), and any untransformed gonocytes are thought to undergo apoptosis. In human cryptorchidism, persisting gonocytes may lead to seminoma. Using Bcl2-associated X knockout (BAXKO) mice, we investigated apoptosis in gonocyte development during mouse minipuberty. Testes from BAXKO, heterozygous (HET), and wild-type (WT) littermates were collected on postnatal days 1, 3, 6, and 9 (n = 6/group), labelled with antibodies against mouse vasa homologue (MVH, germ cell marker) or promyelocytic leukaemia zinc-factor (PLZF, SSC marker) and imaged for cell counting. Total germ cells/tubule, i.e., the number of germ cells on and off the basement membrane (BM), were counted using Image J followed by 2-way ANOVA analysis with Prism. Total PLZF+ germ cells/tubule, PLZF+ germ cells/tubule off BM, total MVH+ germ cells/tubule, and MVH+ germ cells off BM/tubule were significantly higher at day 9 in BAXKO compared to WT and HET mice (p < 0.01). In conclusion, knockout of BAX in mouse leads to gonocytes persisting at the centre of the tubules after minipuberty, which failed to migrate and transform into SSC, indicating the important role of apoptosis is to eliminate undifferentiated gonocytes during transformation. Failed apoptosis in gonocytes may be the cause of malignancy in humans with cryptorchidism.

Investigation of cholestasis-related changes in characteristics of spermatogonial stem cells in testis tissue of male Wistar rats.

Paternal metabolic status is an important factor in the health status of offspring. Cholestasis, as a metabolic disorder, significantly disrupts spermatogenesis. Spermatogonial stem cells (SSCs) are considered the dividing germ cells, which maintain spermatogenesis throughout the lifespan. Here, we investigated the in vivo and in vitro effect(s) of cholestasis on SSCs. Cholestasis was induced in rats by bile duct ligation. Four weeks after the cholestasis induction, testicular tissues were analysed using histopathological examinations. The expression of SSC markers, including Plzf and Thy-1, was determined using the immunofluorescent technique. Also, SSCs were isolated from animals, and their proliferation was examined in vitro. The histological examinations revealed that cholestasis caused irregularities in the structure of seminal tubes. Immunostaining showed that the total number of Thy-1- and Plzf-expressing cells was declined in the cholestasis group compared with the control group. In vitro culture of SSCs indicated that the number of SSC colonies and those expressing Plzf were significantly reduced in the culture medium of the cholestasis group. Our results indicated that cholestasis affects the functionality of SSCs and reduces the number and proliferation of them. This finding may be of interest to the effect of metabolic diseases such as cholestasis on spermatogenesis.

A subpopulation of human Adark spermatogonia behaves as the reserve stem cell.

Human spermatogonial stem cells (SSCs) are an essential source to maintain spermatogenesis as an efficient process for daily sperm production with high self-renewal capacity along adulthood. However, the phenotype and the subpopulation that represent the real reserve SSC for the human testis remain unknown. Moreover, although SSC markers have been described for undifferentiated spermatogonia (Adark and Apale), the existence of a specific subtype that could be identified as the actual/true SSC has not yet been fully determined. Herein we evaluated spermatogonial morphology, kinetics, positioning regarding blood vasculature in relation to protein expression (UTF1, GFRA1, and KIT) as well as proliferative activity (MCM7) and identified a small subpopulation of Adark with nuclear rarefaction zone (AdVac) that behaves as the human reserve SSC. We show that AdVac is the smallest human spermatogonial population (10%), staying quiescent (89%) and positioned close to blood vessels throughout most of the stages of the seminiferous epithelium cycle (SEC) and divides only at stages I and II. Within this AdVac population, we found a smaller pool (2% of A undifferentiated spermatogonia) of entirely quiescent cells exhibiting a high expression of UTF1 and lacking GFRA1. This finding suggests them as the real human reserve SSC (AdVac UTF1+/GFRA1-/MCM7-). Additionally, Adark without nuclear vacuole (AdNoVac) and Apale have similar kinetic and high proliferative capacity throughout the SEC (47%), indicating that they are actively dividing undifferentiated spermatogonia. Identification of human stem cells with evident reserve SSC functionality may help further studies intending to sort SSCs to treat male diseases and infertility.

Effects of Monoterpenes of Trachyspermum ammi on the Viability of Spermatogonia Stem Cells In Vitro.

Trachyspermum ammi (Apiaceae) plants have several medicinal and condimentary applications and are considered an aphrodisiac agent in Iranian Traditional Medicine. Thus, the present study aims to evaluate the effects of oil from Iranian T. ammi plants on the viability of spermatogonial stem cells in vitro. The essential oil of T. ammi fruits was extracted by hydrodistillation, and the amount of thymol was calculated by a gas-chromatography method. Spermatogonial stem cells were isolated from the testes of mice using enzyme digestion. Real-time polymerase chain reaction (RT-PCR) was applied to assess the gene expressions of promyelocytic leukemia zinc finger protein (Plzf), DNA-binding protein inhibitor (ID-4), tyrosine-protein kinase (c-Kit), B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (BAX). The number and diameter of colonies were also measured in the treated cells. The amount of thymol in the oil was 130.7 ± 7.6 µg/mL. Flow cytometry analysis showed that 92.8% of all cells expressed stimulated by retinoic acid 8 (Stra8), a spermatogonial stem cell marker. Expression of Plzf and ID-4 genes significantly increased in the treatment groups, while c-Kit and BAX decreased, and Bcl2 increased in the presence of essential oil. The numbers and diameters of cells were also improved by the application of the plant oil. These data indicated that monoterpenes from the oil of T. ammi improved the quality and viability of spermatogonia cells in the cell culture.

Propagation of goat putative spermatogonial stem cells under growth factors defined serum-free culture conditions.

In the present study, we used a serum-free culture media to propagate goat putative spermatogonial stem cells (SSCs) and evaluated the effect of crucial growth factors on relative expression of some SSC markers and self-renewal related genes. The enriched SSCs were cultured on a homologous Sertoli cell feeder layer in KO-DMEM supplemented with 10% KOSR. Putative SSC colonies emerged between day 6 and 10 which were then characterized by the expression of numerous spermatogonial and pluripotency related markers. After 15 days of subculture, the relative mRNA expression study revealed that 40 ng/mL concentration of Glial cell line-derived neurotrophic factor (GDNF) upregulated the expression of BCL6B, ID4, PLZF, and UCHL1. Moreover, the supplementation of GDNF + bFGF up-regulated the expression of PLZF and BCL6B. UCHL1 expression was higher after addition of GDNF + LIF while, THY1 overexpressed in response to the addition of GDNF + CSF1. These results demonstrated that the goat SSCs were efficiently propagated using a KOSR based serum-free media and the growth factor supplementation markedly influences their gene expression profile.

Comparing the stemness and morphobiometry of spermatogonial stem cells from Doom pig on different days of culture

The present study was conducted to compare the stemness and morphobiometry of spermatogonial stem cells (SSCs) from the Doom pig on different days of culture (9&lt;sup&gt;th&lt;/sup&gt;, 30&lt;sup&gt;th&lt;/sup&gt; and 65&lt;sup&gt;th&lt;/sup&gt; day) for the development of long-term culture method. The testes from 7–15-day old piglets were collected and two-step enzymatic digestion was used to isolate SSCs. Before in vitro culture of SSC-like cells on the Sertoli cell feeder layer, the cells were enriched by differential plating and Percoll density gradient centrifugation. The isolated SSCs were characterised by alkaline phosphatase and immunofluorescence staining and qPCR analysis of SSC specific marker genes. Stemness was compared based on the expression of different SSC specific marker genes. The putative spermatogonial stem cells (PSSCs) from all the days of culture were found to be positive for alkaline phosphatase and immunofluorescence staining. The results from qPCR analysis showed that PSSCs were positive for SSC marker genes, though their expression decreased gradually from day 9 to day 65 of culture. The shape of the cells was found to change from compact round or oval to amorphous shape on day 65 of culture. Colony diameter ranged from 68.92 ± 1.20 µm (day 9) to 213.53 ± 12.52 µm (day 65) and differed significantly from each other. The number of colonies on day 65 of culture was significantly lower than on days 9 and 30. These results suggest that the enriched SSCs from Doom pigs can be maintained up to two months in vitro in the present culture system.

CD2 is a surface marker for mouse and rat spermatogonial stem cells.

The spermatogonial stem cell (SSC) population in testis is small, and the lack of SSC markers has severely handicapped research on these cells. During our attempt to identify genes involved in SSC aging, we found that CD2 is expressed in cultured SSCs. Flow cytometric analysis and spermatogonial transplantation experiments showed that CD2 is expressed in SSCs from mature adult mouse testes. Cultured SSCs transfected with short hairpin RNAs (shRNAs) against CD2 proliferated poorly and showed an increased frequency of apoptosis. Moreover, functional analysis of transfected cells revealed impairment of SSC activity. Fluorescence activated cell sorting and spermatogonial transplantation experiments showed that CD2 is expressed not only in mouse but also in rat SSCs. The results indicate that CD2 is a novel SSC surface marker conserved between mouse and rat SSCs.

Arrestin‐independent constitutive endocytosis of GPR125/ADGRA3

The orphan receptor GPR125 (ADGRA3) belongs to subgroup III of the adhesion G protein−coupled receptor (aGPCR) family. aGPCRs, also known as class B2 GPCRs, share basic structural and functional properties with other GPCRs. Many of them couple to G proteins and activate G protein−dependent and −independent signaling pathways, but little is known about aGPCR internalization and β‐arrestin recruitment. GPR125 was originally described as a spermatogonial stem cell marker and studied for its role in Wnt signaling and cell polarity. Here, using cell‐based assays and confocal microscopy, we show that GPR125 is expressed on the cell surface and undergoes constitutive endocytosis in a β‐arrestin−independent, but clathrin‐dependent manner, as indicated by colocalization with transferrin receptor 1, an early endosome marker. These data support that the constitutive internalization of GPR125 contributes to its biological functions by controlling receptor surface expression and accessibility for ligands. Our study sheds light on a new property of aGPCRs, namely internalization; a property described to be important for signal propagation, signal termination, and desensitization of class A (rhodopsin‐like) and B1 (VIP/secretin) GPCRs.

Xeno-Free Propagation of Spermatogonial Stem Cells from Infant Boys.

Spermatogonial stem cell (SSC) transplantation therapy is a promising strategy to renew spermatogenesis for prepubertal boys whose fertility is compromised. However, propagation of SSCs is required due to a limited number of SSCs in cryopreserved testicular tissue. This propagation must be done under xeno-free conditions for clinical application. SSCs were propagated from infant testicular tissue (7 mg and 10 mg) from two boys under xeno-free conditions using human platelet lysate and nutrient source. We verified SSC-like cell clusters (SSCLCs) by quantitative real-time polymerase chain reaction (PCR) and immune-reaction assay using the SSC markers undifferentiated embryonic cell transcription factor 1 (UTF1), ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1), GDNF receptor alpha-1 (GFRα-1) Fα and promyelocytic leukaemia zinc finger protein (PLZF). The functionality of the propagated SSCs was investigated by pre-labelling using green fluorescent Cell Linker PKH67 and xeno-transplantation of the SSCLCs into busulfan-treated, therefore sterile, immunodeficient mice. SSC-like cell clusters (SSCLCs) appeared after 2 weeks in primary passage. The SSCLCs were SSC-like as the UTF1, UCHL1, GFRα1 and PLZF were all positive. After 2.5 months’ culture period, a total of 13 million cells from one sample were harvested for xenotransplantation. Labelled human propagated SSCs were identified and verified in mouse seminiferous tubules at 3–6 weeks, confirming that the transplanted cells contain SSCLCs. The present xeno-free clinical culture protocol allows propagation of SSCs from infant boys.

Moderate hypoxia modulates ABCG2 to promote the proliferation of mouse spermatogonial stem cells by maintaining mild ROS levels

The aim of this study was to investigate the effects of different oxygen (O2) concentrations on the growth of mouse spermatogonial stem cells (SSCs) and the possible mechanisms of cell proliferation in vitro. The SSCs from testicular cells were cultured in various O2 concentrations (1%, 2.5%, 5%, and 20% O2) for 7 days. Colonies of SSCs were identified morphologically and by immunofluorescence. The number of mouse SSC colonies and the area covered by them were measured. Cell cycle progression of the SSCs was analyzed to identify the state of cell proliferation. The effects of O2 concentrations on the levels of intracellular reactive oxygen species (ROS) and expression of ATP binding cassette subfamily G member 2 (ABCG2) were also analyzed in the SSCs. Following culturing for 7 days, the SSCs were treated with Ko143 (a specific inhibitor of ABCG2) for 1 h, and the ROS level and expression of bcl-2, bax, and p53 were analyzed. The results showed that mouse SSCs formed compact colonies and had unclear borders in different O2 concentrations for 7 days, and there were no major morphologic differences between the O2 treatment groups. The expression of the SSC marker, GFR α1 was studied in each O2 treatment group. The number and area of SSC colonies, and the number of GFR α1 positive cells were the highest in the 2.5% O2 treatment group. Compared with other O2 concentrations, the number of cells in G0 cycle was significantly higher, while the level of intracellular ROS was lower at 1% O2. Moreover, the intracellular ROS levels gradually increased with increasing O2 concentration from 1% to 20%. The expression of ABCG2 in the SSCs cultured at 2.5% O2 was higher than in the other O2 groups. Inhibition of ABCG2 increased intracellular ROS generation, and the expression of the pro-apoptotic genes bax and p53, and decreased the expression of the anti-apoptotic gene bcl-2. In conclusion, moderate to low O2 tension increases ABCG2 expression to maintain mild ROS levels, triggers the expression of the anti-apoptotic genes, suppresses the proapoptotic gene pathway, and further promotes the proliferation of mouse SSCs in vitro.

Propagation of Spermatogonial Stem Cell-Like Cells From Infant Boys

BackgroundGonadotoxic treatment of malignant diseases as well as some non-malignant conditions such as cryptorchidism in young boys may result in infertility and failure to father children later in life. As a fertility preserving strategy, several centers collect testicular biopsies to cryopreserve spermatogonial stem cells (SSCs) world-wide. One of the most promising therapeutic strategies is to transplant SSCs back into the seminiferous tubules to initiate endogenous spermatogenesis. However, to obtain sufficient numbers of SSC to warrant transplantation, in vitro propagation of cells is needed together with proper validation of their stem cell identity.Materials and MethodsA minute amount of testicular biopsies (between 5 mg and 10 mg) were processed by mechanical and enzymatic digestion. SSCs were enriched by differential plating method in StemPro-34 medium supplemented with several growth factors. SSC-like cell clusters (SSCLCs) were passaged five times. SSCLCs were identified by immunohistochemical and immunofluorescence staining, using protein expression patterns in testis biopsies as reference. Quantitative polymerase chain reaction analysis of SSC markers LIN-28 homolog A (LIN28A), G antigen 1 (GAGE1), promyelocytic leukemia zinc finger protein (PLZF), integrin alpha 6 (ITGA6), ubiquitin carboxy-terminal hydrolase L1 (UCHL1) and integrin beta 1 (ITGB1) were also used to validate the SSC-like cell identity.ResultsProliferation of SSCLCs was achieved. The presence of SSCs in SSCLCs was confirmed by positive immunostaining of LIN28, UCHL1 and quantitative polymerase chain reaction for LIN28A, UCHL1, PLZF, ITGA6, and ITGB1, respectively.ConclusionThis study has demonstrated that SSCs from infant boys possess the capacity for in vitro proliferation and advance a fertility preservation strategy for pre-pubertal boys who may otherwise lose their fertility.