Background In the differentiation of mouse embryonic stem (ES) cells into neurons using the 5-stage method, cells in stage 4 are in general used as neural progenitors (NPs) because of their ability ...to give rise to neurons. The choice of stage 4 raises several questions about neural progenitors such as the type of cell types that are specifically considered to be neural progenitors, the exact time when these progenitors become capable of neurogenesis and whether neurogenesis is an independent and autonomous process or the result of an interaction between NP cells and the surrounding cells. Methodology/Principal Findings In this study, we found that the confluent monolayer cells and neural sphere like cell clusters both appeared in the culture of the first 14 days and the subsequent 6 weeks. However, only the sphere cells are neural progenitors that give rise to neurons and astrocytes. The NP cells require 14 days to mature into neural lineages fully capable of differentiation. We also found that although the confluent monolayer cells do not undergo neurogenesis, they play a crucial role in the growth, differentiation, and apoptosis of the sphere cells, during the first 14 days and long term culture, by secreted factors and direct cell to cell contact. Conclusions/Significance The sphere cells in stage 4 are more committed to developing into neural progenitors than monolayer cells. Interaction between the monolayer cells and sphere cells is important in the development of stage 4 cell characteristics.
E2 (oestradiol‐17β) is an important hormone that regulates various cell functions including insulin production. hIPCs (human islet‐derived precursor cells) are capable of proliferating and ...differentiating into cells that secrete insulin in response to glucose in vivo and in vitro. However, the effect of E2 on hIPCs is currently unclear. In this study, we found that ERα (oestrogen receptor alpha), but not ERβ, was expressed on hIPCs, and E2 promoted the proliferation and inhibited the differentiation of adult hIPCs. Although fetal hIPCs also express ERα, no effect of E2 on the fetal hIPCs was observed, suggesting differing roles of E2 at different stages of pancreatic development. This study indicates that E2 may be one of the key factors that control the turnover of adult pancreatic β cells by regulating the proliferation and differentiation of adult hIPCs through ERα.
The utility of induced pluripotent stem cells (iPSCs) as models to study diseases and as sources for cell therapy depends on the integrity of their genomes. Despite recent publications of DNA ...sequence variations in the iPSCs, the true scope of such changes for the entire genome is not clear. Here we report the whole-genome sequencing of three human iPSC lines derived from two cell types of an adult donor by episomal vectors. The vector sequence was undetectable in the deeply sequenced iPSC lines. We identified 1058–1808 heterozygous single nucleotide variants (SNVs), but no copy number variants, in each iPSC line. Six to twelve of these SNVs were within coding regions in each iPSC line, but ~50% of them are synonymous changes and the remaining are not selectively enriched for known genes associated with cancers. Our data thus suggest that episome-mediated reprogramming is not inherently mutagenic during integration-free iPSC induction.
We report here the study of different peripherally modified palladium phthalocyanine (PdPc) encapsulated in silica gel glass obtained by sol–gel technique. The resulted composites were transparent ...and homogeneous with required optical limiting properties. Trapping effect was checked by UV/Vis absorption spectra and pore structure of the composites. Optical limiting properties were measured at 532 nm with 8 ns pulses. The results show that all the PdPcs have better optical limiting effect in composite than in solution, among which, PdPc-C has the best optical limiting effect due to its largest peripheral substituent.
Recent studies on the identification of stem/progenitor cells within adult mouse and human pancreatic islets have raised the possibility that autologous transplantation might be used in treating type ...1 diabetes. However, it is not yet known whether such stem/progenitor cells are impaired in type 1 diabetic patients or diabetic animal models. The latter would also allow us to test the efficacy of autologous transplantation in large animal models prior to clinical applications. The present study aims to determine the existence of stem/progenitor cells in the islets of diabetic monkey models and to assess the proliferation and differentiation potential of such cells in vitro. Our results indicate that there are pancreatic progenitor cells in the adult pancreatic islets in both normal and type 1 diabetic monkeys. The isolated pancreatic progenitor cells can be greatly expanded in culture. Upon the removal of growth medium, these cells spontaneously form islet-like cell clusters, which could be further induced to secrete insulin by inductive factors. Furthermore, the secretion of insulin and C-peptide from the islet-like cell clusters responds to glucose and other stimuli, indicating that the differentiated cells not only resemble β-cells but also possess the unique biological function of β-cells. This study provides a foundation for further characterization of adult pancreatic progenitor cells and autologous transplantation using pancreatic progenitor cells in treating diabetic monkeys.
Mesenchymal stem cells (MSCs) have received considerable attention for various therapeutic approaches in recent years. MSCs are also easy to genetically modify to express therapeutic genes by using ...lentiviral vectors. Because of the similarities in genetics, physiology and metabolism between non-human primates (NHPs) and humans, NHPs models are invaluable for researching human disorders and for developing therapeutic strategies. Therefore, MSCs derived from NHPs could be a powerful tool for cell therapy and genetic engineering. Studies from captive and free-ranging adult NHPs show that up to 100% were infected with simian foamy virus (SFV). In this study, we found that all cultured MSCs derived from adult cynomolgus monkey were infected with SFV by RT-PCR. Therefore, antiviral drugs must be added in MSCs culture. However, because of SFV infection and additive antiviral drugs, the infection efficiency of the lentiviral vectors reduced significantly. In this study, we improved the infection efficiency by disabl
Background: The chemoresistance of prostate cancer (PCa) is invariably associated with the aggressiveness and metastasis of this disease. New emerging evidence indicates that the ...epithelial-to-mesenchymal transition (EMT) may play pivotal roles in the development of chemoresistance and metastasis. As a hallmark of EMT, E-cadherin is suggested to be a key marker in the development of chemoresistance. However, the molecular mechanisms underlying PCa chemoresistance remain unclear. The current study aimed to explore the association between EMT and chemoresistance in PCa as well as whether changing the expression of E-cadherin would affect PCa chemoresistance.Methods: Parental PC3 and DU145 cells and their chemoresistant PC3-TxR and DU145-TxR cells were analyzed. PC3-TxR and DU145-TxR cells were transfected with E-cadherin-expressing lentivirus to overexpress E-cadherin; PC3 and DU145 cells were transfected with small interfering RNA to silence E-cadherin. Changes of EMT phenotype-related markers and signaling pathways were assessed by Western blotting and quantitative real-time polymerase chain reaction. Tumor cell migration, invasion, and colony formation were then evaluated by wound healing, transwell, and colony formation assays, respectively. The drug sensitivity was evaluated using MTS assay. Results: Chemoresistant PC3-TxR and DU145-TxR cells exhibited an invasive and metastatic phenotype that associated with EMT, including the down-regulation of E-cadherin and up-regulation of Vimentin, Snail, and N-cadherin,comparing with that of parental PC3 and DU145 cells. When E-cadherin was overexpressed in PC3-TxR and DU145- TxR cells, the expression of Vimentin and Claudin-1 was down-regulated, and tumor cell migration and invasion were inhibited. In particular, the sensitivity to paclitaxel was reactivated in E-cadherin-overexpressing PC3-TxR and DU145-TxR cells. When E-cadherin expression was silenced in parental PC3 and DU145 cells, the expression of Vimentin and Snail was up-regulated, and, particularly, the sensitivity to paclitaxel was decreased. Interestingly, Notch-1 expression was up-regulated in PC3-TxR and DU145-TxR cells, whereas the E-cadherin expression was down-regulated in these cells comparing with their parental cells. The use of γ-secretase inhibitor, a Notch signaling pathway inhibitor, significantly increased the sensitivity of chemoresistant cells to paclitaxel.Conclusion: The down-regulation of E-cadherin enhances PCa chemoresistance via Notch signaling, and inhibiting the Notch signaling pathway may reverse PCa chemoresistance.
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