We demonstrate that the quantity of IL-7 and Notch signaling differentially regulate lymphocyte fate. We also identify ILC progenitor and immature ILC2 in the fetal mesentery, which are terminally differentiated and matured by PDGFRα+gp38+ mesenchymal cells.

The clinical need for platelet transfusions is increasing; however, donor-dependent platelet transfusions are associated with practical problems, such as the limited supply and the risk of infection. Thus, we developed a manufacturing system for platelets from a donor-independent cell source: a human adipose-derived mesenchymal stromal/stem cell line (ASCL). The ASCL was obtained using an upside-down culture flask method and satisfied the minimal criteria for defining mesenchymal stem cells (MSCs) by The International Society for Cellular Therapy. The ASCL showed its proliferation capacity for ≥2 months without any abnormal karyotypes. The ASCL was cultured in megakaryocyte induction media. ASCL-derived megakaryocytes were obtained, with a peak at day 8 of culture, and ASCL-derived platelets (ASCL-PLTs) were obtained, with a peak at day 12 of culture. We observed that CD42b+ cells expressed an MSC marker (CD90) which is related to cell adhesion. Compared with peripheral platelets, ASCL-PLTs exhibit higher levels of PAC1 binding, P-selectin surface exposure, ristocetin-induced platelet aggregation, and ADP-induced platelet aggregation, as well as similar levels of fibrinogen binding and collagen-induced platelet aggregation. ASCL-PLTs have lower epinephrine-induced platelet aggregation. The pattern of in vivo kinetics after infusion into irradiated immunodeficient NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ mice was similar to that of platelet concentrates. ASCL-PLTs have similar characteristics to those of peripheral platelets and might have an additional function as MSCs. The establishment of the ASCL and its differentiation into ASCL-PLTs do not require gene transfer, and endogenous thrombopoietin is used for differentiation. The present protocol is a simple method that does not require feeder cells, further enhancing the clinical application of our approach.

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Platelets, which contain many growth factors such as platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β), are being used in clinical applications as platelet-rich plasma (PRP). Only a few studies, however, have been conducted on the growth factors present in PRP and on the clinical applications using the drug delivery system (DDS). For the purpose of clinical application, we first modified the PRP preparation method and assessed the amounts of growth factors contained in the human platelet concentrates. Furthermore, we assessed fibrin glue as a DDS of platelet concentrates. Platelet precipitations were made by twice centrifuging human whole blood. The precipitated platelet was resuspended to yield the platelet concentrates. The growth factor concentrations were measured. Fibrin glue sheets containing this platelet concentrate were implanted in rabbit pinna and samples were obtained for immunostaining (anti-PDGF antibody) to assess the use of PRP over time using the fibrin glue as the DDS. The mean concentration of growth factors present in the platelet concentrates was three times or greater than that of conventional PRP. Furthermore, the results indicated that when the platelet concentrate was used with fibrin glue as a carrier, the contents were released over a period of about 1 week. This raises the possibility that this system may be useful in clinical applications.

Head and neck squamous cell carcinoma (HNSCC) includes both morphological and functional cellular heterogeneity, as would be expected if it arose from dysregulated stem or progenitor cells as opposed to the simple clonal expansion of a mutated cell; however, stemness molecule expression levels and distribution in HNSCC remain unclear. To clarify this, stemness molecule expressions were determined in HNSCC, as well as their properties and prognosis. Two protooncogenic chromatin regulators, Bmi-1 and high-mobility-group A2 (Hmga2), were identified in 12 pair cases of HNSCC tumor regions by comparison with their non-cancerous background tissues using cDNA microarray. Both Bmi-1 and Hmga2 are known to promote stem cell self-renewal by negatively regulating the expressions of Ink4a and Arf tumor suppressors. Despite similar targets, Bmi-1 protein was expressed in an early cancerous region and HMGA2 protein was expressed in a region showing more progression. Similarly, Bmi1 expression had no significance with regard to overall survival (P ¼ 0.67), whereas HMGA2 expression was associated with decreased overall survival (P ¼ 0.05). Quantitative realtime reverse transcription polymerase chain reaction analyses also correlated with protein levels. These findings suggest that Bmi-1 is an early detection marker to distinguish cancerous from non-cancerous regions, whereas HMGA2 is presumed to be a tumor prognosis marker. Among our HNSCC analyses, these stemness molecules expressed fewer primitive rare cells in the tumor than all other cells in the tumor. HNSCC cells with high expression of stemness molecules partly behave like stem cells. Head and neck squamous cell carcinoma (HNSCC) is typically associated with virus infection, persistent chronic inflammation, and tobacco and alcohol use. Survival rates have changed in the last 40 years because of reductions in these factors; 1 however, the mortality rate remains high because advanced and recurrent locoregional control is difficult in many cases. Better understanding of the biology of HNSCC is required to define relevant targets and to develop novel therapeutic approaches. HNSCCs have both morphological and functional cellular heterogeneity, as would be expected if they arose from dysregulated stem or progenitor cells as opposed to the simple clonal expansion of a mutated cell. 2 Recently, numerous reports have shown support for the 'cancer stem cell' theory in many types of tumor, including HNSCC. 3,4,5 Acute and chronic myeloid leukemias follow the cancer stem cell model. Both tumors show robustly hematopoietic hierarchical organization in the tumor cells; 6,7 however, for solid cancers such as squamous cell carcinoma, it is not clear how generalizable the cancer stem cell model is. Not all cancer cells have the same capacity to proliferate. 8 In some cancers, most cancer cells appear to have limited ability to proliferate, while in the same tumors, stochastic minority populations of stemness molecules highly expressed in cancer as a 'stem-like cancer' retain the capacity...