Cdk2ap2 is a novel regulator for self-renewal of murine embryonic stem cells

Evaluation of microRNA expression profiles in human sperm frozen using permeable cryoprotectant-free droplet vitrification and conventional methods

For sperm cryopreservation, the conventional method, which requires glycerol, has been used for a long time. In addition, the permeable cryoprotectant-free vitrification method has been continuously studied. Although the differences of cryopreservation effects between the two methods have being studied, differences in microRNA (miRNA) profiles between them remain unclear. In this study, we investigated the differences in miRNA expression profiles among conventional freezing sperm, droplet vitrification freezing sperm and fresh human sperm. We also analyzed the differences between these methods in terms of differentially expressed miRNAs (DEmiRs) related to early embryonic development and paternal epigenetics. Our results showed no significant differences between the cryopreservation methods in terms of sperm motility ratio, plasma membrane integrity, DNA integrity, mitochondrial membrane potential, acrosome integrity, and ultrastructural damage. However, sperm miRNA-sequencing showed differences between the two methods in terms of the numbers of DEmiRs (28 and 19 with vitrification using a nonpermeable cryoprotectant and the conventional method, respectively) in postthaw and fresh sperm specimens. DEmiRs related to early embryonic development and paternal epigenetics mainly included common DEmiRs between the groups. Our results showed that the differences between conventional freezing and droplet vitrification were minimal in terms of miRNA expression related to embryonic development and epigenetics. Changes in sperm miRNA expression due to freezing are not always detrimental to embryonic development. This study compared differences in miRNA expression profiles before and after cryopreservation between cryopreservation by conventional and vitrification methods. It offers a new perspective to evaluate various methods of sperm cryopreservation.

Transcriptomic Effects on the Mouse Heart Following 30 Days on the International Space Station

Efforts to understand the impact of spaceflight on the human body stem from growing interest in long-term space travel. Multiple organ systems are affected by microgravity and radiation, including the cardiovascular system. Previous transcriptomic studies have sought to reveal the changes in gene expression after spaceflight. However, little is known about the impact of long-term spaceflight on the mouse heart in vivo. This study focuses on the transcriptomic changes in the hearts of female C57BL/6J mice flown on the International Space Station (ISS) for 30 days. RNA was isolated from the hearts of three flight and three comparable ground control mice and RNA sequencing was performed. Our analyses showed that 1147 transcripts were significantly regulated after spaceflight. The MAPK, PI3K-Akt, and GPCR signaling pathways were predicted to be activated. Transcripts related to cytoskeleton breakdown and organization were upregulated, but no significant change in the expression of extracellular matrix (ECM) components or oxidative stress pathway-associated transcripts occurred. Our results indicate an absence of cellular senescence, and a significant upregulation of transcripts associated with the cell cycle. Transcripts related to cellular maintenance and survival were most affected by spaceflight, suggesting that cardiovascular transcriptome initiates an adaptive response to long-term spaceflight.

Investigate the stemness of adult adipose-derived stromal cells based on single-cell RNA-sequencing

The cellular heterogeneity and genetic features of stemness of adipose-derived stromal cells (ADSCs) remain unclear. Using single-cell RNA sequencing (scRNA-seq), we investigated the genomic features of the stemness gene in ADSCs with genetic variability. We cultured the ADSCs isolated from the fat waste of a healthy adult volunteers undergoing cosmetic plastic surgery to the third generation, used the BD Rhapsody platform to perform scRNA-seq, then used Monocle2 to analyze the growth and development trajectory of ADSCs, Cellular Trajectory Reconstruction Analysis Using Gene Counts and Expression (CytoTRACE) to evaluate the stemness gene characteristics in ADSCs clusters, and Beam to analyze the expression change characteristics of the main stemness related genes of ADSCs. According to the scRNA-seq data of 5325 ADSCs, they could be classified into nine cell clusters. According to CytoTRACE analysis, Cluster 3 of ADSCs had the highest stemness, whereas Cluster 8 had the lowest stemness. Pseudotime analysis revealed that Cluster 3 of ADSCs was primarily dispersed in the middle part of the growth and development trajectory, whereas Cluster 8 was primarily distributed at the end. We summarized the stemness of Cluster 3 in ADSCs with high expression of TPM1 and CCND1 genes in the metaphase of growth and development is the strongest, whereas the stemness of Cluster 8 with high expression of FICD, CREBRF, SDF2L1, HERPUD1, and HYOU1 genes in the telophase of growth and development is the weakest, providing a theoretical basis for screening and improving the therapeutic effect of ADSCs in cell transplantation research.

Knockdown of CDK2AP1 in human embryonic stem cells reduces the threshold of differentiation

Recent studies have suggested a role for the Cyclin Dependent Kinase-2 Associated Protein 1 (CDK2AP1) in stem cell differentiation and self-renewal. In studies with mouse embryonic stem cells (mESCs) derived from generated mice embryos with targeted deletion of the Cdk2ap1 gene, CDK2AP1 was shown to be required for epigenetic silencing of Oct4 during differentiation, with deletion resulting in persistent self-renewal and reduced differentiation potential. Differentiation capacity was restored in these cells following the introduction of a non-phosphorylatible form of the retinoblastoma protein (pRb) or exogenous Cdk2ap1. In this study, we investigated the role of CDK2AP1 in human embryonic stem cells (hESCs). Using a shRNA to reduce its expression in hESCs, we found that CDK2AP1 knockdown resulted in a significant reduction in the expression of the pluripotency genes, OCT4 and NANOG. We also found that CDK2AP1 knockdown increased the number of embryoid bodies (EBs) formed when differentiation was induced. In addition, the generated EBs had significantly higher expression of markers of all three germ layers, indicating that CDK2AP1 knockdown enhanced differentiation. CDK2AP1 knockdown also resulted in reduced proliferation and reduced the percentage of cells in the S phase and increased cells in the G2/M phase of the cell cycle. Further investigation revealed that a higher level of p53 protein was present in the CDK2AP1 knockdown hESCs. In hESCs in which p53 and CDK2AP1 were simultaneously downregulated, OCT4 and NANOG expression was not affected and percentage of cells in the S phase of the cell cycle was not reduced. Taken together, our results indicate that the knockdown of CDK2AP1 in hESCs results in increased p53 and enhances differentiation and favors it over a self-renewal fate.

Grainyhead-like 2 regulates epithelial plasticity and stemness in oral cancer cells

Grainyhead-like 2 (GRHL2) is one of the three mammalian homologues of Drosophila Grainyhead involved in epithelial morphogenesis. We recently showed that GRHL2 also controls normal epithelial cell proliferation and differentiation. In this study, we investigated the role of GRHL2 in oral carcinogenesis and the underlying mechanism. GRHL2 expression was elevated in cells and tissues of oral squamous cell carcinomas (OSCCs) compared with normal counterparts. Knockdown of GRHL2 resulted in the loss of in vivo tumorigenicity, cancer stemness and epithelial phenotype of oral cancer cells. GRHL2 loss also inhibited oral cancer cell proliferation and colony formation. GRHL2 regulated the expression of miR-200 family and Octamer-binding transcription factor 4 (Oct-4) genes through direct promoter DNA binding. Overexpression of miR-200 genes in the oral cancer cells depleted of GRHL2 partially restored the epithelial phenotype, proliferative rate and cancer stemness, indicating that miR-200 genes in part mediate the functional effects of GRHL2. Taken together, this study demonstrates a novel connection between GRHL2 and miR-200, and supports protumorigenic effect of GRHL2 on OSCCs.

Gene expression changes during retinal development and rod specification

PURPOSE

Retinitis pigmentosa (RP) typically results from individual mutations in any one of >70 genes that cause rod photoreceptor cells to degenerate prematurely, eventually resulting in blindness. Gene therapies targeting individual RP genes have shown efficacy at clinical trial; however, these therapies require the surviving photoreceptor cells to be viable and functional, and may be economically feasible for only the more commonly mutated genes. An alternative potential treatment strategy, particularly for late stage disease, may involve stem cell transplants into the photoreceptor layer of the retina. Rod progenitors from postnatal mouse retinas can be transplanted and can form photoreceptors in recipient adult retinas; optimal numbers of transplantable cells are obtained from postnatal day 3-5 (P3-5) retinas. These cells can also be expanded in culture; however, this results in the loss of photoreceptor potential. Gene expression differences between postnatal retinas, cultured retinal progenitor cells (RPCs), and rod photoreceptor precursors were investigated to identify gene expression patterns involved in the specification of rod photoreceptors.

METHODS

Microarrays were used to investigate differences in gene expression between cultured RPCs that have lost photoreceptor potential, P1 retinas, and fresh P5 retinas that contain significant numbers of transplantable photoreceptors. Additionally, fluorescence-activated cell sorting (FACS) sorted Rho-eGFP-expressing rod photoreceptor precursors were compared with Rho-eGFP-negative cells from the same P5 retinas. Differential expression was confirmed with quantitative polymerase chain reaction (q-PCR).

RESULTS

Analysis of the microarray data sets, including the use of t-distributed stochastic neighbor embedding (t-SNE) to identify expression pattern neighbors of key photoreceptor specific genes, resulted in the identification of 636 genes differentially regulated during rod specification. Forty-four of these genes when mutated have previously been found to cause retinal disease. Although gene function in other tissues may be known, the retinal function of approximately 61% of the gene list is as yet undetermined. Many of these genes' promoters contain binding sites for the key photoreceptor transcription factors Crx and Nr2e3; moreover, the genomic clustering of differentially regulated genes appears to be non-random.

CONCLUSIONS

This study aids in understanding gene expression differences between rod photoreceptor progenitors versus cultured RPCs that have lost photoreceptor potential. The results provide insights into rod photoreceptor development and should expedite the development of cell-based treatments for RP. Furthermore, the data set includes a large number of retinopathy genes; less-well-characterized genes within this data set are a resource for those seeking to identify novel retinopathy genes in patients with RP (GEO accession: GSE59201).

Effect of bisphenol A on pluripotency of mouse embryonic stem cells and differentiation capacity in mouse embryoid bodies

Bisphenol A (BPA) poses potential risks to reproduction and development. However, the mechanism of BPA's effects on early embryonic development is still unknown. Embryonic stem cells (ESC) and embryoid bodies (EB) provide valuable in vitro models for testing the toxic effects of environmental chemicals in early embryogenesis. In this study, mouse embryonic stem cells (mESC) were acutely exposed to BPA for 24h, and general cytotoxicity and the effect of BPA on pluripotency were then evaluated. Meanwhile, mouse embryoid bodies (mEB) were exposed to BPA up to 6 days and their differentiation capacity was evaluated. In mESC and mEB, we found that BPA up-regulated pluripotency markers (Oct4, Sox2 and Nanog) at mRNA and/or protein levels. Moreover, BPA increased the mRNA levels of endodermal markers (Gata4,Sox17) and mesodermal markers (Sma,Desmin), and reduced the mRNA levels of ectodermal markers (Nestin,Fgf5) in mEB. Furthermore, microRNA(miR)-134, an expression inhibitor of pluripotency markers including Oct4, Sox2 and Nanog, was decreased both in BPA-treated mESC and mEB. These results firstly indicate that BPA may disturb pluripotency in mESC and differentiation of mEB, and may inhibit ectodermal lineage differentiation of mEB while miR-134 may play a key role underlying this effect.