Kyoto probe-1 reveals phenotypic differences between mouse ES cells and iTS-P cells

Improved Production of Induced Pluripotent Stem Cells Using Dot Pattern Culture Plates

The rate of cell proliferation is a crucial factor in cell production under good manufacturing practice (GMP) control. In this study, we identified a culture system for induced pluripotent cells (iPSCs) that supports cell proliferation and viability and maintains the cells in an undifferentiated state even at 8 days after seeding. This system involves the use of dot pattern culture plates that have been coated with a chemically defined scaffold which has high biocompatibility. Under cell starvation conditions, where medium exchange was not performed for 7 days or where the amount of medium exchange was reduced to half or a quarter, iPSC viability and lack of differentiation were maintained. The rate of cell viability in this culture system was greater than generally obtained by standard culture methods. The cells in this compartmentalized culture system could be induced to differentiate in a controlled and consistent manner: differentiation of endoderm occurred in a controlled and consistent manner: endoderm, mesoderm, and ectoderm could be consistently induced to differentiate in the cultures. In conclusion, we have developed a culture system that supports high viability in iPSCs and allows their controlled differentiation. This system has the potential for use in GMP-based production of iPSCs for clinical purposes.

A Simplified and Effective Approach for the Isolation of Small Pluripotent Stem Cells Derived from Human Peripheral Blood

Pluripotent stem cells are key players in regenerative medicine. Embryonic pluripotent stem cells, despite their significant advantages, are associated with limitations such as their inadequate availability and the ethical dilemmas in their isolation and clinical use. The discovery of very small embryonic-like (VSEL) stem cells addressed the aforementioned limitations, but their isolation technique remains a challenge due to their small cell size and their efficiency in isolation. Here, we report a simplified and effective approach for the isolation of small pluripotent stem cells derived from human peripheral blood. Our approach results in a high yield of small blood stem cell (SBSC) population, which expresses pluripotent embryonic markers (e.g., Nanog, SSEA-3) and the Yamanaka factors. Further, a fraction of SBSCs also co-express hematopoietic markers (e.g., CD45 and CD90) and/or mesenchymal markers (e.g., CD29, CD105 and PTH1R), suggesting a mixed stem cell population. Finally, quantitative proteomic profiling reveals that SBSCs contain various stem cell markers (CD9, ITGA6, MAPK1, MTHFD1, STAT3, HSPB1, HSPA4), and Transcription reg complex factors (e.g., STAT5B, PDLIM1, ANXA2, ATF6, CAMK1). In conclusion, we present a novel, simplified and effective isolating process that yields an abundant population of small-sized cells with characteristics of pluripotency from human peripheral blood.

Gene Expression in Pancreatic Cancer-Like Cells and Induced Pancreatic Stem Cells Generated by Transient Overexpression of Reprogramming Factors

We previously reported that transient overexpression of reprogramming factors can be used to generate induced pluripotent stem (iPS) cells, induced tissue-specific stem (iTS) cells, and fibroblast-like (iF) cells from pancreatic tissue. iF cells have tumorigenic ability and behave similarly to pancreatic cancer cells. In this study, we analyzed gene expression in iF cells and iTS-P cells (iTS cells from pancreatic tissue) via microarray analysis and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The expression levels of the Mybl2 and Lyn genes, which are reported to be oncogenes, were significantly higher in iF cells than in iTS-P cells. The expression level of Nestin, which is expressed in not only pancreatic progenitor cells but also pancreatic ductal adenocarcinomas, was also higher in iF cells than in iTS-P cells. Itgb6 and Fgf13, which are involved in the pathogenesis of diseases such as cancer, exhibited higher expression levels in iF cells than in iTS-P cells. Unexpectedly, the expression levels of genes related to epithelial-mesenchymal transition (EMT), except Bmp4, were lower in iF cells than in iTS-P cells. These data suggest that the Mybl2, Lyn, Nestin, Itgb6, and Fgf13 genes could be important biomarkers to distinguish iTS-P cells from iF cells.