Search

Self‐renewal and differentiation of male germline stem cells (mGSCs) provide the basic function for continual spermatogenesis. Studies of in vitro culture of germline stem cells are important and meaningful for basic biological research and practical application. Growth factors, such as GDNF, bFGF, CSF1, and EGF, could maintain the self‐renewal of mGSCs. Insulin‐like growth factor 1 (IGF‐1), an important growth factor, and its pathway have been reported to maintain the survival of several types of stem cells and play important roles in male reproduction. However, the mechanism through which the IGF‐1 pathway acts to regulate the self‐renewal of mGSCs remains unclear. We analyzed the effect of IGF‐1 on the proliferation and apoptosis of bovine mGSCs. We evaluated the expression profile of long noncoding RNA (LncRNA) H19 in bovine and mouse tissues. Moreover, we investigated whether LncRNA H19 could regulate the IGF‐1 pathway. Results showed that IGF‐1 could activate the phosphorylation of AKT and ERK signaling pathways, and the IGF‐1 pathway played an important role in regulating the proliferation and apoptosis of bovine mGSCs. The proliferation rate of mGSCs decreased, whereas the apoptosis rate of mGSCs increased when the IGF‐1 receptor (IGF‐1R) was blocked using the IGF‐1R‐specific inhibitor (picropodophyllin). LncRNA H19 could regulate the IGF‐1 signaling pathway and, consequently, the proliferation and apoptosis of mGSCs. The number of cells in the seminiferous tubule decreased when H19 was interfered by injecting a virus‐containing supernatant. Hence, LncRNA H19 participated in the regulation of the proliferation and apoptosis of mGSCs via the IGF‐1 signaling pathway. In this study, we show that the IGF‐1 signaling pathway plays an important role in regulating the proliferation and apoptosis of bovine mGSCs, and LncRNA H19 regulates the IGF‐1 signaling pathway by influencing the expression of IGF‐1R. [ABSTRACT FROM AUTHOR]

Promyelocytic leukemia zinc finger PLZF, known as ZBTB16 or ZFP145 is a critical zinc finger protein of male germline stem cells (mGSCs), it's an essential transcriptional factor for goat testis development and spermatogenesis. Loss of PLZF results in progressive depletion of SSCs after the first wave of spermatogenesis leading to eventual spermatogenic arrest, apparently the result of a shift in the balance in SSC fate away from self‐renewal and toward differentiation. Cumulating evidences have demonstrated that microRNAs are expressed in a cell‐specific or stage‐specific manner during spermatogenesis and acts as regulators on specific makers such as Stra8, ETV5, and PLZF. However, the post transcriptional function of PLZF still poorly elucidate in mGSCs. Bioinformatic analysis and dual luciferase reporter assay showed that miR‐19b‐3p binds the 3′UTR of PLZF, suggesting that PLZF is a direct target of miR‐19b‐3p. The profile of miR‐19b‐3p and PLZF analyzed in dairy goat testis at different age showed that miR‐19b‐3p was significantly up‐regulated in goat testis at 1, 3, 6 months and downregulated at 12, 18, and 24 months which was inversely correlated with PLZF in the same testis. Focusing on the role of miR‐19b‐3p, we found that miR‐19b‐3p changes c‐KIT and mTOR signaling through PLZF to promote proliferation in goat nGSCs and infertile mice testes. Over‐expression of PLZF significantly reversed miR‐19b‐3p‐mediated proliferation in mice testes. We found also that miR‐19b‐3p reduced heterochromatin‐mediated senescence through PLZF localized on HP1α. Taken together, our findings indicate that miR‐19b‐3p promotes proliferation and reduces heterochromatin‐mediated senescence through PLZF in mGSCs. [ABSTRACT FROM AUTHOR]

The protein encoded by double sex and mab-3 related transcription factor 1 (Dmrt1) gene contains a double sex/mab-3 domain, which was considered as one of the most conservative structures in sex determination. However, its effect on spermatogenesis of dairy goat spermatogonial stem cells (SSCs) remains to be clarified. For the first time, the roles of Dmrt1 in spermatogenesis of livestock are highlighted. Here, we investigated the expression pattern of Dmrt1 in the testes of dairy goats. Dmrt1 primarily located in undifferentiated SSCs. Moreover, Dmrt1 enhanced differentiation and proliferation of mGSCs. On the contrary, the level of meiosis was down-regulated, as Dmrt1 determines whether SSCs undergo mitosis and spermatogonial differentiation or meiosis. In the busulfan-treated mice testes, Dmrt1 repair germ cell damage was emphasized as well. Our results exposed that Dmrt1 maintenance mGSCs in two ways: facilitating proliferation and self-renewal of SSCs; and reducing the inflammatory response caused by reproductive injury. These findings identify a central role for Dmrt1 in controlling population stability and injury restoring of SSCs. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the effect of platelet-derived growth factor (PDGF) on the proliferation of human umbilical cord mesenchymal stem cells (UC-MSCs) and further explore the mechanism of PDGF in promoting the proliferation of UC-MSCs. The human UC-MSCs were treated with different concentrations of PDGF, and the effects were evaluated by counting the cell number, the cell viability, the expression of PDGF receptors analyzed by RT-PCR, and the detection of the gene expression of cell proliferation, cell cycle and pluripotency, and Brdu assay by immunofluorescent staining and Quantitative real-time (QRT-PCR). The results showed that PDGF could promote the proliferation of UC-MSCs in vitro in a dose-dependent way, and 10 to 50 ng/ml PDGF had a significant proliferation effect on UC-MSCs; the most obvious concentration was 50 ng/ml. Significant inhibition on the proliferation of UC-MSCs was observed when the concentration of PDGF was higher than 100 ng/ml, and all cells died when the concentration reached 200 ng/ml PDGF. The PDGF-treated cells had stronger proliferation and antiapoptotic capacity than the control group by Brdu staining. The expression of the proliferation-related genes C-MYC, PCNA and TERT and cell cycle-related genes cyclin A, cyclin 1 and CDK2 were up-regulated in PDGF medium compared with control. However, pluripotent gene OCT4 was not significantly different between cells cultured in PDGF and cells analyzed by immunofluorescence and QRT-PCR. The PDGF could promote the proliferation of human UC-MSCs in vitro. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

XBP1 is a transcription factor that plays a central role in controlling cellular responses to endoplasmic reticulum stress (ERS). Under stress conditions, the transcriptionally active form of XBP1 is generated by splicing of XBP1 mRNA by the ER-resident protein inositol-requiring enzyme-1α (IRE1α). This study aimed to investigate the role of XBP1 in male reproductive disorders. XBP1s-overexpressing goat spermatogonial stem cells (gSSCs) showed higher proliferative ability in vitro and in vivo. These cells also showed higher antioxidant capacity. In comparison, XBP1 knockdown significantly suppressed proliferation. Further analysis showed that XBP1 could stimulate the secretion of IL-6 from macrophages. Overall, the results indicate that XBP1s functions to enhance the proliferation ability and antioxidant capacity of gSSCs, potentially through a mechanism involving the regulation of gSSCs by macrophages. • The male reproductive dysfunction caused by LPS mainly damages germ cells except for spermatogonial stem cells (SSCs). • XBP1 was highly expressed in SSCs in LPS model. • The XBP1s-overexpressing gSSC (goat spermatogonial stem cell) presents the higher proliferative ability in vitro and in vivo. • XBP1 also affected the SSC by regulating the secretion of macrophages IL-6. [ABSTRACT FROM AUTHOR]

Porcine pancreatic stem cells (PSCs) are one kind of the potential cells for treatment of human diabetes. Autophagy is a highly conserved cellular degradation process in which it helps to maintain the balance between the synthesis, degradation and subsequent recycling of cellular components. However, how autophagy contributes to PSCs has not yet been investigated. Here, we established GFP-LC3 transfected porcine PSC lines in which the accumulation of autophagosomes can be efficiently visualized to evaluate the autophagic activity. Moreover, we observed that starved PSCs which showed increased autophagic activity exhibited an increased tendency to proliferate through the results of BrdU, flow cytometry and western blotting. Furthermore, increased expression of active β-catenin after inducing autophagy indicated that it might be the canonical Wnt signaling that autophagy activated to exert the function on the stimulation of PSCs proliferation. Collectively, these results demonstrated that autophagy stimulated proliferation of PSCs might be regulated by the canonical Wnt signaling pathway. Our results for the first time shed light on a role of autophagy for stimulating the proliferation of porcine PSCs. [ABSTRACT FROM AUTHOR]

• Folic acid promotes the proliferation of pPSCs by binding to FOLRα. • Folic acid increases the efficiency of directed differentiation of pPSCs into insulin-producing cells in vitro. • Canonical Wnt and ERK signaling pathway participate in the regulation of folic acid on proliferation and differentiation of pPSCs. Porcine pancreatic stem cells (pPSCs) can be induced to differentiate into insulin-producing cells in vitro and thus serve as a major cells source for β-cell regeneration. However, this application is limited by the weak cell proliferation ability and low insulin induction efficiency. In this study, we explored the role of folic acid in the proliferation of pPSCs and the formation of insulin-secreting cells. We found that FA-treated pPSCs cells had a high EDU positive rate, and the proliferation marker molecules PCNA, CyclinD1 and c-Myc were up-regulated, while the expression of folate receptor α (FOLRα) was up-regulated. In further research, interference FOLRα or adding canonical Wnt signaling pathway or ERK signaling pathway inhibitors could significantly inhibit the effect of FA on pPSCs proliferation. Meanwhile, during the differentiation of pPSCs into insulin-secreting cells, we found that the maturation marker genes Insulin, NKX6.1, MafA, and NeuroD1 was upregulated in insulin-secreting cell masses differentiationed from pPSCs after FA treatment, and the functional molecules Insulin and C-peptide were increased, the ability to secrete insulin in response to high glucose was also increased. With the addition of Wnt and ERK signaling pathway inhibitors, the pro-differentiation effect of FA was weakened. In conclusion, FA promotes the proliferation of pPSCs by binding to folate receptor α (FOLRα) and increase the efficiency of directed differentiation of pPSCs into insulin-producing cells by regulating canonical Wnt and ERK signaling pathway. This study lays theoretical foundation for solving the bottleneck in the treatment of diabetes with stem cell transplantation in future. [ABSTRACT FROM AUTHOR]

Eukaryotic translation initiation factor 2 subunit 3 and structural gene Y-linked (Eif2s3y) gene, the gene encoding eIF2γ protein, is globally expressed in all tissues and plays important roles in regulating global and gene-specific mRNA translation initiation. It has been noticed that Eif2s3y plays crucial roles in spermatogenesis, however, the mechanism remains unclear. In the current study, transgenic Eif2s3y mice were generated to test our hypothesis that the Eif2s3y promotes the proliferation of spermatogonial stem cells (SSCs). Transgenic Eif2s3y mouse had enhanced SSCs proliferation rate when compared to WT mouse. Interesting, the testes from transgenic Eif2s3y mouse had increased Active-β-catenin protein expression and higher expression pattern of Wnt ligand Wnt6 when compared to testes from WT mouse. This study revealed novel roles of Eif2s3y in the activation Wnt6/β-catenin signal pathway in SSCs. Taken together, we identified Eif2s3y - Wnt6 -β-catenin as a critical pathway in the regulation of spermatogenesis, which provides a platform for investigating the molecular mechanisms of male reproduction. • The transgenic Eif2s3y mouse showed enhances spermatogonial cell proliferation. • Eif2s3y regulates Wnt6 of SSCs and Sertoli cells to promote the proliferation of spermatogonial stem cells. • Eif2s3y - Wnt6 -β-catenin as a critical pathway in the regulation of spermatogenesis. [ABSTRACT FROM AUTHOR]

Porcine pancreatic stem cells (pPSCs) can be induced to insulin-secreting cells and therefore considered the most promising seeding cells for curing human diabetes in future. However, insufficient pPSCs number is one of the bottleneck problems before its clinical application. SerpinB1 is a serine protease inhibitor in neutrophils and can directly promote the proliferation of β cells. Whether SerpinB1 is involved in pPSC proliferation and differentiation remains unknown. The effects of SerpinB1 on pPSCs proliferation were measured by Cell Counting Kit-8, 5-ethynyl-2′-deoxyuridine, qRT-PCR, western blot, and flow cytometry assays. We found that pPSCs did not efficiently reach the S phase when SerpinB1 expression was knocked down with short hairpin RNA (sh-SerpinB1), the expression of Cyclin D1 , CDK-2 , and PCNA also decreased. Meanwhile, cell viability and proliferation ability were both declined. Further analyses showed that the expression level of phosphorylated STAT3/STAT3was downregulated, along with an upregulation of p53 and p21. We used a two-step induction method to induce pPSCs to insulin-secreting cells and found that SerpinB1 expression in insulin-secreting cells was higher than in pPSCs. Meanwhile, the protein expression level of phosphorylated STAT3/STAT3 was increased while p53 and p21 was decreased in induced insulin-secreting cells in comparison with control cells. The insulin-secreting cells derived from the sh-SerpinB1 cells secreted less insulin and showed poor sensitivity to high glucose than control group. However, the insulin-secreting cells derived from the ov-SerpinB1 cells has a quite contrary tendency. In conclusion, this study demonstrates that SerpinB1 promotes the proliferation of pPSCs through the STAT3 signaling pathway, and SerpinB1 is a key factor for maintaining the viability of pPSCs during the transition to insulin-secreting cells. [ABSTRACT FROM AUTHOR]