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Premature ovarian failure (POF) is one of the most common causes of infertility in women. In our present study, we established cyclophosphamide- (CTX-) induced POF rat model and elucidated its effect on ovarian function. We detected the serum estrogen, follicle stimulating hormone, and anti-Müllerian hormone of mice models by ELISA and evaluated their folliculogenesis by histopathology examination. Our study revealed that CTX administration could severely disturb hormone secretion and influence folliculogenesis in rat. This study also detected ovarian cells apoptosis by deoxy-UTP-digoxigenin nick end labeling (TUNEL) and demonstrated marked ovarian cells apoptosis in rat models following CTX administration. In order to explore the potential of human umbilical cord mesenchymal stem cells (UCMSCs) in POF treatment, the above indexes were used to evaluate ovarian function. We found that human UCMSCs transplantation recovered disturbed hormone secretion and folliculogenesis in POF rat, in addition to reduced ovarian cell apoptosis. We also tracked transplanted UCMSCs in ovaries by fluorescence in situ hybridization (FISH). The results manifested that the transplanted human UCMSCs could reside in ovarian tissues and could survive for a comparatively long time without obvious proliferation. Our present study provides new insights into the great clinical potential of human UCMSCs in POF treatment.

One of the most important changes during sperm capacitation is the enhancement of tyrosine phosphorylation. However, the mechanisms of protein tyrosine phosphorylation during sperm capacitation are not well studied. We used label-free quantitative phosphoproteomics to investigate the overall phosphorylation events during sperm capacitation in humans and identified 231 sites with increased phosphorylation levels. Motif analysis using the NetworKIN algorithm revealed that the activity of tyrosine phosphorylation kinases insulin growth factor 1 receptor (IGF1R)/insulin receptor is significantly enriched among the up-regulated phosphorylation substrates during capacitation. Western blotting further confirmed inhibition of IGF1R with inhibitors GSK1904529A and NVP-AEW541, which inhibited the increase in tyrosine phosphorylation levels during sperm capacitation. Additionally, sperm hyperactivated motility was also inhibited by GSK1904529A and NVP-AEW541 but could be up-regulated by insulin growth factor 1, the ligand of IGF1R. Thus, the IGF1R-mediated tyrosine phosphorylation pathway may play important roles in the regulation of sperm capacitation in humans and could be a target for improvement in sperm functions in infertile men. Molecular & Cellular Proteomics 14: 10.1074/mcp.M114.045468, 1104-1112, 2015.Austin (1) and Chang (2) discovered that sperm must reside in the female genital tract for a specific period of time to acquire the ability to fertilize an egg and named this process "capacitation." During capacitation, several biochemical changes occur, including enhancement of tyrosine phosphorylation (3), increased intracellular Ca 2ϩ and cAMP levels (4), hyperactivated motility (5), and increased membrane plasma permeability (6). Mature sperm are highly differentiated and specialized cells, there is almost no transcription, and the genomic ribosome is inactive (5). Therefore, regulation of proteins at the level of post-translational modification is expected to play important roles in sperm functions. In mammalian sperm, phosphorylated proteins, protein kinases, and phosphatases are reported to function in sperm motility, capacitation, and acrosome reaction (7, 8). Tyrosine phosphorylation and dephosphorylation are required for sperm to reach, bind, penetrate, and fuse with the oocyte (5). Tyrosinephosphorylated proteins have been found in human (9), monkey (10), rat (11), and mouse (12) sperm. The sperm tail is the main location of protein tyrosine phosphorylation, and tyrosine phosphorylation of the sperm tail is related to hyperactivated motility (13). However, the mechanism of protein tyrosine phosphorylation regulation in sperm capacitation is not well studied. With high throughput ability, proteomics has been used to characterize phosphorylation in sperm. For the human sperm, Ficarro et al. (14) used two-dimensional polyacrylamide gel electrophoresis (PAGE), anti-phosphotyrosine antibody labeling, and tandem mass spectrometry (MS/MS) to identify tyrosine phosphoproteins during capacitation. They identified...

N-Linked glycosylation, a type of post-translational modification, plays important roles in cell-cell recognition, adhesion, and interactions. Although N-linked glycosylated proteins in sperm are known to be important for gamete binding, little is known about the composition of these proteins, particularly glycosylation sites, in humans. In the present study, the use of glyco-FASP, coupled with the tandem mass spectrometry (MS/MS) method, led to the identification of 554 N-glycosylation sites and 297 N-glycosylated proteins in human sperm. Bioinformatics analysis revealed enrichment of proteins with functions in cell recognition and fertilization. Overall, about 91% of the human sperm N-glycosylated proteins were classified into "membrane", "extracellular region", and "lysosome" groups, based on subcellular localization annotation. Furthermore, glutathione peroxidase 4 (GPX4), a membrane glycoprotein identified in our glycoproteome, was shown to play a significant role in gamete interactions using the in vitro fertilization assay. Accordingly, we propose that characterization of the human sperm glycoproteome should effectively aid in clarifying the mechanisms of fertilization and provide a valuable resource for the future development of male contraceptives and diagnosis of male infertility.

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Spermatogonial stem cells (SSCs) are undifferentiated cells that are required to maintain spermatogenesis throughout the reproductive life of mammals. Although SSC transplantation and culture provide a powerful tool to identify the mechanisms regulating SSC function, the precise signalling mechanisms governing SSC self-renewal and specific surface markers for purifying SSCs remain to be clearly determined. In the present study, we established a steady SSC culture according to the method described by Shinohara's lab. Fertile progeny was produced after transplantation of cultured SSCs into infertile mouse testis, and the red fluorescence exhibited by the culture cell membranes was stably and continuously transmitted to the offspring. Next, via advanced mass spectrometry and an optimized proteomics platform, we constructed the proteome profile, with 682 proteins expressed in SSCs. Furthermore bioinformatics analysis showed that the list contained several known molecules that are regulated in SSCs. Several nucleoproteins and membrane proteins were chosen for further exploration using immunofluorescence and RT-PCR. The results showed that SALL1, EZH2, and RCOR2 are possibly involved in the self-renewal mechanism of SSCs. Furthermore, the results of tissue-specific expression analysis showed that Gpat2 and Pld6 were uniquely and highly expressed in mouse testes and cultured SSCs. The cellular localization of PLD6 was further explored and the results showed it was primarily expressed in the spermatogonial membrane of mouse testes and cultured SSCs. The proteins identified in this study form the basis for further exploring the molecular mechanism of self-renewal in SSCs and for identifying specific surface markers of SSCs.

Background Osteosarcoma (OS) is the most common malignant tumor of bone, and the clinical efficacy of current treatments and associated survival rates need to be further improved by employing novel therapeutic strategies. Although various studies have shown that BMI1 protein is universally upregulated in OS cells and tissues, its specific role and underlying mechanism have not yet been fully explored. Methods Expression of BMI1 protein in OS cells was detected by western blot. The effect of BMI1 on proliferation and migration of OS cells (143B and U-2OS cell lines) was investigated in vitro using CCK-8, colony formation and transwell assays, and in vivo using subcutaneous tumorigenesis and lung metastasis assays in xenograft nude mice. Expression of epithelial–mesenchymal transition (EMT)-associated proteins was detected by immunofluorescence imaging. Bioinformatic analysis was performed using ENCODE databases to predict downstream targets of BMI1. SIK1 mRNA expression in osteosarcoma cells was detected by quantitative real-time reverse transcription PCR (qPCR). Chromatin immunoprecipitation-qPCR (ChIP-qPCR) was used to investigate expression of BMI1-associated, RING1B-associated, H2AK119ub-associated and H3K4me3-associated DNA at the putative binding region of BMI1 on the SIK1 promoter in OS cells. Results Using both in vitro and in vivo experimental approaches, we found that BMI1 promotes OS cell proliferation and metastasis. The tumor suppressor SIK1 was identified as the direct target gene of BMI1 in OS cells. In vitro experiments demonstrated that SIK1 could inhibit proliferation and migration of OS cells. Inhibition of SIK1 largely rescued the altered phenotypes of BMI1-deficient OS cells. Mechanistically, we demonstrated that BMI1 directly binds to the promoter region of SIK1 in a complex with RING1B to promote monoubiquitination of histone H2A at lysine 119 (H2AK119ub) and inhibit H3K4 trimethylation (H3K4me3), resulting in inhibition of SIK1 transcription. We therefore suggest that BMI1 promotes OS cell proliferation and metastasis by inhibiting SIK1. Conclusions Our results reveal a novel molecular mechanism of OS development promoted by BMI1 and provides a new potential target for OS treatment.

Ovarian physiology and pathology are important areas of scientific research. Efforts have been made to identify the ovary-related transcriptomes in different species. However, the proteomic studies are limited. The rhesus monkey is very similar to humans, and it is widely used in the study of reproductive biology and medicine. In this study, using an optimized proteomics platform, we successfully identified 5723 rhesus ovarian proteins, of which 4325 proteins were consistently identified in all three replicates and with at least 2 unique peptides. The 4325 proteins were chosen for further analysis. Through gene ontology and pathway analyses, we obtained a preliminary understanding of the function of these proteins. A random immunohistochemistry analysis was used to determine the expression of proteins in various cell types. By comparing the genes identified in this study with genes that were reported to have relatively high levels of expression in human oocytes, we obtained genes that were predicted to play roles in maintenance of normal ovarian physiology. Searching the identified genes from this study against the MGI database gave us a list of proteins those exist in the rhesus monkey ovary and are important for female mouse reproduction as well. The overlap of genes in this study and the genes whose abnormal expression or dysfunction were reported to be associated with human polycystic ovary syndrome (PCOS) and premature ovarian failure (POF) prompted us to use the rhesus monkey to study these two common causes of female infertility. This study may provide a basis for future studies of human reproductive disorders using the rhesus monkey as a model.