https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/49782/1/Yamanaka_Cell_131_5.pdf

Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined Factors

Somatic cell nuclear transfer allows trans-acting factors present in the mammalian oocyte to reprogram somatic cell nuclei to an undifferentiated state. We show that four factors (OCT4, SOX2, NANOG, and LIN28) are sufficient to reprogram human somatic cells to pluripotent stem cells that exhibit the essential characteristics of embryonic stem (ES) cells. These induced pluripotent human stem cells have normal karyotypes, express telomerase activity, express cell surface markers and genes that characterize human ES cells, and maintain the developmental potential to differentiate into advanced derivatives of all three primary germ layers. Such induced pluripotent human cell lines should be useful in the production of new disease models and in drug development, as well as for applications in transplantation medicine, once technical limitations (for example, mutation through viral integration) are eliminated.

https://science.sciencemag.org/content/sci/318/5858/1917.full.pdf

Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells

The transcription factor NF-kappaB has been the focus of intense investigation for nearly two decades. Over this period, considerable progress has been made in determining the function and regulation of NF-kappaB, although there are nuances in this important signaling pathway that still remain to be understood. The challenge now is to reconcile the regulatory complexity in this pathway with the complexity of responses in which NF-kappaB family members play important roles. In this review, we provide an overview of established NF-kappaB signaling pathways with focus on the current state of research into the mechanisms that regulate IKK activation and NF-kappaB transcriptional activity.

/pdf/signaling-to-nf-kappab-1zyb7vgt7s.pdf

Signaling to NF-kappaB.

The complexity of the human brain has made it difficult to study many brain disorders in model organisms, highlighting the need for an in vitro model of human brain development Here we have developed a human pluripotent stem cell-derived three-dimensional organoid culture system, termed cerebral organoids, that develop various discrete, although interdependent, brain regions These include a cerebral cortex containing progenitor populations that organize and produce mature cortical neuron subtypes Furthermore, cerebral organoids are shown to recapitulate features of human cortical development, namely characteristic progenitor zone organization with abundant outer radial glial stem cells Finally, we use RNA interference and patient-specific induced pluripotent stem cells to model microcephaly, a disorder that has been difficult to recapitulate in mice We demonstrate premature neuronal differentiation in patient organoids, a defect that could help to explain the disease phenotype Together, these data show that three-dimensional organoids can recapitulate development and disease even in this most complex human tissue

/pdf/cerebral-organoids-model-human-brain-development-and-3wt90buxu3.pdf

Cerebral organoids model human brain development and microcephaly

Pluripotency pertains to the cells of early embryos that can generate all of the tissues in the organism. Embryonic stem cells are embryo-derived cell lines that retain pluripotency and represent invaluable tools for research into the mechanisms of tissue formation. Recently, murine fibroblasts have been reprogrammed directly to pluripotency by ectopic expression of four transcription factors (Oct4, Sox2, Klf4 and Myc) to yield induced pluripotent stem (iPS) cells. Using these same factors, we have derived iPS cells from fetal, neonatal and adult human primary cells, including dermal fibroblasts isolated from a skin biopsy of a healthy research subject. Human iPS cells resemble embryonic stem cells in morphology and gene expression and in the capacity to form teratomas in immune-deficient mice. These data demonstrate that defined factors can reprogramme human cells to pluripotency, and establish a method whereby patient-specific cells might be established in culture.

/pdf/reprogramming-of-human-somatic-cells-to-pluripotency-with-4lycgkg8te.pdf

Reprogramming of human somatic cells to pluripotency with defined factors

Induced pluripotent stem (iPS) cells have been generated from mouse and human fibroblasts by the retroviral transduction of four transcription factors. However, the cell origins and molecular mechanisms of iPS cell induction remain elusive. This report describes the generation of iPS cells from adult mouse hepatocytes and gastric epithelial cells. These iPS cell clones appear to be equivalent to embryonic stem cells in gene expression and are competent to generate germline chimeras. Genetic lineage tracings show that liver-derived iPS cells are derived from albumin-expressing cells. No common retroviral integration sites are found among multiple clones. These data suggest that iPS cells are generated by direct reprogramming of lineage-committed somatic cells and that retroviral integration into specific sites is not required.

https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/124215/3/yigak03256.pdf

Generation of Pluripotent Stem Cells from Adult Mouse Liver and Stomach Cells

Clinical application of embryonic stem (ES) cells faces difficulties regarding use of embryos, as well as tissue rejection after implantation. One way to circumvent these issues is to generate pluripotent stem cells directly from somatic cells. Somatic cells can be reprogrammed to an embryonic-like state by the injection of a nucleus into an enucleated oocyte or by fusion with ES cells. However, little is known about the mechanisms underlying these processes. We have recently shown that the combination of four transcription factors can generate ES-like pluripotent stem cells directly from mouse fibroblast cultures. The cells, named induced pluripotent stem (iPS) cells, can be differentiated into three germ layers and committed to chimeric mice. Here we describe detailed methods and tips for the generation of iPS cells.

Induction of pluripotent stem cells from fibroblast cultures.

We evaluated the teratoma-forming propensity of secondary neurospheres (SNS) generated from 36 mouse induced pluripotent stem (iPS) cell lines derived in 11 different ways. Teratoma-formation of SNS from embryonic fibroblast-derived iPS cells was similar to that of SNS from embryonic stem (ES) cells. In contrast, SNS from iPS cells derived from different adult tissues varied substantially in their teratoma-forming propensity, which correlated with the persistence of undifferentiated cells.

/pdf/variation-in-the-safety-of-induced-pluripotent-stem-cell-1os6laomfm.pdf

Variation in the safety of induced pluripotent stem cell lines

https://repository.kulib.kyoto-u.ac.jp/dspace/bitstream/2433/85336/1/j.stem.2009.08.001.pdf

Hypoxia Enhances the Generation of Induced Pluripotent Stem Cells

### Immunogenicity of Induced Pluripotent Stem Cells Zhao et al Nature . 2011. doi:10.1038/nature10135

A new study shows the immunogenicity of induced pluripotent stem cells by the direct transplantation of undifferentiated cells into syngenic mice. 

The reprogramming of somatic cells into pluripotent stem cells has been reported after introducing a combination of several defined factors, such as OCT3/4, SOX2, KLF4, and c-MYC, into the cells.1 These artificially established cells are termed induced pluripotent stem cells (iPSCs). The iPSCs show unlimited growth while maintaining their potential for differentiation into various cell types of all 3 germ layers. Their pluripotency has been clearly shown by their contribution to chimeric animals and by the development of a full-term mouse during a tetraploid complementation experiment. These data also indicated that cells differentiated from iPSCs can at least partially replace the biological functions of various organs. Unlike embryonic stem cells (ESCs), iPSCs can be generated from a patient's own somatic cells. Therefore, the potential utility of iPSCs for regenerative medicine has been suggested.

The development of iPSC-derived differentiated cells has been expected to provide personalized cells for cell-based therapy. However, the immunogenicity of these cells had not yet been strictly examined. Recently, Zhao et al. reported that the transplantation of immature iPSCs induced a T-cell–dependent immune response even in a syngenic mouse.2 When injected into immunodeficient mice, undifferentiated pluripotent cells grow locally, differentiate, and form teratomas that contain various cell types, including neurons, cartilage, keratinocytes, and intestinal epithelium. In this study, the authors investigated the immunoreactions …

Keisuke Okita

Papers

Generation of Pluripotent Stem Cells from Adult Mouse Liver and Stomach Cells

Induction of pluripotent stem cells from fibroblast cultures.

Variation in the safety of induced pluripotent stem cell lines

Hypoxia Enhances the Generation of Induced Pluripotent Stem Cells

Immunogenicity of Induced Pluripotent Stem Cells