Cytotoxic T lymphocytes (CTLs) represent the most promising therapeutic avenue in cancer immunotherapy, yet most of the currently ongoing trials utilizing CTLs are still not effective enough to cure patients. To overcome this problem, we came up with the idea to apply induced pluripotent stem cell (iPSC) technology to the cloning and expansion of CTLs. When iPSCs are established from antigen-specific T cells (T-iPSCs), these T-iPSCs should inherit rearranged genomic structures of T cell receptor genes, and thus all T cells regenerated from T-iPSCs should express the same T cell receptor (TCR). Since iPSCs can be expanded almost unlimitedly, it is possible to obtain as many fresh CTLs as needed. Pursuing this idea, we have recently succeeded in regenerating melanoma antigen MART1-specific CTLs from T-iPSCs originally derived from a melanoma patient. Our study illustrates an approach for the cloning and expansion of functional antigen-specific CTLs that might be applicable in cell-based cancer therapy.

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The discovery of induced pluripotent stem cells (iPSCs) has the potential to drastically alter the future of medicine. Further, the achievement of cell lineage conversion by gene transduction is expected to make a dramatic contribution to the advancement of basic biology. Currently, various iPSC applications have been the focus of much attention due to their potential in regenerative medicine. Nevertheless, because the molecular mechanisms underlying the creation of these cells have remained elusive, confidence in their safe use in a clinical setting has remained rather shaky. In our present review, we discuss genome integrity during iPSC generation, with a particular focus on point mutations, to further address the issue of whether iPSC generation causes genetic aberrations.

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Mesenchymal stem/stromal cells (MSC) present in many tissues that are multipotent which can differentiate into several different cell types. Mesenchymal stem cells are alsobelieved to act on the inflammatory-immune reactions in the local to release humoral factors by integrating the tissue injury site. MSCs migrate to the damaged tissue site to involve in tissue repair when they administered exogenously. Communicating with the inflammatory microenvironment is an important part of this process. In recent years, it has been studied that the cellular and molecular mechanisms of interaction between MSC and the various participants in inflammation. Depending on their type and strength of the inflammatory stimulus, the MSC changes its role either for suppressive or inducible for the immune response. Here, we review the current paradigm about the immunomodulatory functions of MSCs in according with our recent finding of cGVHD animal model study.

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Recent progress of manipulating pluripotent stem cells expands possibilities of regenerative medicine and opens novel transplantation medicine. However, in many cases of these medicines, the relationship between therapeutic cells and recipients would be allogeneic. In this context, we proposed new concept of immune regulation therapy in new-age medicine using pluripotent stem cells. In our concept, not only grafts but also immune regulating cells are generated from pluripotent stem cells by exertion of its pluripotency. We have recently developed immune suppressive macrophage-like cells from pluripotent stem cells. These cells suppressed allo-antigen stimulated T cell proliferation in an iNOS dependent manner. Furthermore, these immune suppressive macrophage-like cells derived from pluripotent stem cells prolonged survival of grafts derived from same pluripotent stem cells in allogeneic recipients. Thus, series of our study proved the efficacy of our new immune regulating strategy in the age of regenerative medicine which utilize pluripotent stem cells as a therapeutic cell source.

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Transforming growth factor-β (TGF-β) is a multifunctional cytokine that play critical roles in melanoma progression. Although the impact of TGF-β signaling on melanoma progression has been well characterized, little is known about the molecular mechanisms that control TGF-β production in melanoma cells. In this study, we describe a novel role for Melanocortin Receptor 1 (MC1R) in the regulation of TGF-β production. MC1R is a cell surface endocytic receptor expressed in melanoma cells and serves as a receptor for α-Melanocyte Stimulating Hormone (α-MSH). The activation of MC1R with α-MSH resulted in increased levels of TGF-β, which was mediated by ERK1/2 and p38 signaling pathways. Furthermore, Microphthalmia Transcription Factor (MITF), the master regulator of melanocytes, was found to act downstream of MC1R to regulate TGF-β production. Targeting of MC1R-MITF axis was effective to decrease TGF-β production, and resulted in delayed tumor growth of B16 melanoma in vivo. Collectively, these results give new insight into the molecular mechanisms that control TGF-β production in melanoma cells.

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Objective: We have recently demonstrated that the generation of pre-plasmacytoid dendritic cells (pre-pDC) from bone marrow (BM) CD34+ cells is increased in rheumatoid arthritis (RA) compared with osteoarthritis (OA) in correlation with the degree of synovial proliferation. It has been shown that FLT3 ligand promotes the differentiation of pDC through its interaction with FLT3 on pDC precursors. We explored the expression of FLT3 mRNA in BM CD34+ cells in RA to delineate the mechanism for their abnormal differentiation into pre-pDC.
Methods: CD34+ cells were purified from BM samples obtained from 46 RA patients and from 29 OA patients during joint operations via aspiration from the iliac crest. The expression of FLT3 mRNA was examined by quantitative RT-PCR.
Results: The expression of FLT3 mRNA was significantly higher in RA BM CD34+ cells than in OA BM CD34+ cells (FLT3/β-actin: [0.686 ± 0.152] × 10^-3 and [0.252 ± 0.053] × 10^-3 [mean ± SEM], respectively; p=0.0269). FLT3 mRNA expression was not correlated with serum CRP or with administration of methotrexate or oral steroid. Finally, TNF-α did not enhance FLT3 mRNA expression, but rather decreased it, in BM CD34+ cells from normal individuals.
Conclusions: These results indicate that FLT3 mRNA expression is upregulated in RA BM CD34+ cells independently of the systemic inflammation or treatment regimens. The data therefore suggest that abnormal FLT3 mRNA expression in BM CD34+ cells might lead to the expansion of immature pDC in RA BM, supporting the enhanced output of pDC into the inflamed synovium in RA.

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Objective: The aim of this study was to establish a novel rat model of neonatal complications secondary to intra-amniotic infection/inflammation in order to investigate the therapeutic efficacy of rat umbilical cord-derived mesenchymal stem cells (rUCMSCs).
Methods: On gestational age day (GAD) 16, approximately 0.2 μg of lipopolysaccharide (LPS) was directly injected into the amniotic cavity of a pregnant rat. Placental inflammation on GAD 20 was histologically evaluated and the cytokine (Il-1β, Tnfα, Mcp-1, Il-6, Cxcl-1) and prostaglandin synthesis enzyme (Cox-1, Cox-2) expression patterns were analyzed by quantitative real-time polymerase chain reaction. Neonatal lung and brain injuries on postnatal day (PND) 14 were assessed histologically. rUCMSCs were injected intravenously into pups to investigate their therapeutic efficacy.
Results: LPS significantly decreased alive-birth rates. Significant increases in inflammatory cell infiltration and up-regulation of Mcp-1 and Cox-2 expression were observed in the placenta. In the neonates, the areas staining positive for myelin basic protein in the brain and radial alveolar counts in the lungs were significantly reduced in the LPS group compared with the control group. rUCMSCs improved myelination and alveolarization.
Conclusion: Intrauterine injection of LPS causes placental inflammation along with neonatal brain and lung injuries in neonatal rats. Postnatal administration of rUCMSCs alleviates these neonatal complications.

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