This study was undertaken to evaluate whether exosomes from human adipose-derived stem cells (ASC-exo) can stimulate the regeneration of human dermal fibroblasts (HDFs). Immunoblotting and FACS analyses showed that ASC-exo was positive for exosome markers. Fluorescence tracking revealed that the contents of ASCexo were transferred into the HDFs. ASC-exo treatment also stimulated the proliferation and migration of HDFs in a dose-dependent manner. Similarly, the expression levels of genes involved in skin cell proliferation were increased by ASC-exo. Microarray analysis showed an enrichment of microRNAs that have regenerative function. We suggest that the ASC-exo can stimulate skin cell proliferation. | BACKGROUNDIt has been well reported that adipose tissue-derived stem cell (ASC) secretes various soluble factors, that is growth factors, cytokines, exosomes that can rescue damaged cells.[1] Exosome, a 30-to 150-nm-sized extracellular vesicle that is secreted from most cell types, is formed within endosomal compartments and released into the extracellular milieu.[2] It has been demonstrated that exosomes possess similar functional properties of mesenchymal stem cells (MSCs) from which they are derived, [3] and due to such functions, exosomes are regarded now as a communicator between tissues.[4] Functionally, exosomes can reduce the immune recognition, so that the integrity of cell membrane can be maintained. [5] A study of stem cell transplantation therapy demonstrated that the role of MSCs in cell-tocell communication was exerted through a paracrine mechanism and that exosomes play a major role in this process.[6] Other findings also described that the conditioned media of ASC (ASC-CM) [7] or exosomes [8] were able to promote the migration of dermal fibroblasts during the process of wound healing. [7] Although the mechanism of the exosomes' role on proliferation and migration of fibroblasts was demonstrated, [8] no study has been conducted to identify the expressional changes of microRNAs, which play major role in various cellular responses, including proliferation. | QUESTIONS ADDRESSEDWe asked whether ASC-derived exosomes can stimulate the skin dermal fibroblasts' proliferation and migration, and by what mechanism these exosomes play such functions. | EXPERIMENTAL DESIGNSee supplementary information. | RESULTSTransmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) showed that ASC-exo isolated from the supernatants (Fig. S1A). Western blot analysis revealed that ASC-exo expresses exosome markers HSP70, CD63and CD9 (Fig. S1B), while these markers were absent in ASC lysate.Flow cytometry analysis also showed that ASC-exos were positive for CD9, CD63 and CD81 (Fig. S1C). We next asked whether the contents of ASC-exos could be transmitted to HDFs. After co-incubation, for 24 hours, of PKH26-labelled ASC-exos with HDFs, it was found that red fluorescence of PKH26 was localized within the cytoplasm of HDFs (Fig. S1D), showing that ASC-exo can be internalized intoHDFs. Also, quantitati...

Epstein-Barr virus (EBV) is a herpesvirus associated with lymphomas and carcinomas. While EBV-associated epithelial cell lines are good model systems to investigate the role of EBV in carcinoma, only a few cell lines are available as they are hard to acquire. A greater variety of naturally EBV-infected cell lines which are derived from tumour patients are needed to represent various features of EBVaGC. We characterized cell line YCCEL1, established from a Korean EBVaGC patient, to ascertain whether it can be used to study the roles of EBV in EBVaGC. The expression of EBV genes and cell surface markers was examined by in situ hybridization, RT-PCR, Western blot analysis, immunofluorescence assay and Northern blot analysis. EBV episomal status was analysed by Southern blotting and real-time PCR. This cell line expressed EBV nuclear antigen 1 (EBNA1) and latent membrane protein 2A (LMP2A), but not EBNA2, LMP2B nor LMP1. The majority of the lytic proteins were not detected in YCCEL1 cells either before or after treatment with 12-O-tetradecanoylphorbol-13-acetate. YCCEL1 cells expressed BART microRNAs (miRNAs) at high level but did not express BHRF1 miRNAs. YCCEL1 cells expressed cytokeratin, but not CD21 and CD19, suggesting CD21-independent EBV infection. The latent EBV gene and EBV miRNA expression pattern of YCCEL1 cells closely resembled that of general EBVaGC cases. Our results support the value of YCCEL1 cells as a good model system to study the role of EBV in gastric carcinogenesis.

BackgroundPreviously, we reported that neonatal porcine pancreatic cells transfected with hepatocyte growth factor (HGF) gene in an Epstein-Barr virus (EBV)-based plasmid (pEBVHGF) showed improved proliferation and differentiation compared to those of the control. In this study, we examined if pancreatic cells transfected repeatedly with pEBVHGF can be successfully grafted to control blood glucose in a diabetes mouse model.MethodsNeonatal porcine pancreatic cells were cultured as a monolayer and were transfected with pEBVHGF every other day for a total of three transfections. The transfected pancreatic cells were re-aggregated and transplanted into kidney capsules of diabetic nude mice or normal nude mice. Blood glucose level and body weight were measured every other day after transplantation. The engraftment of the transplanted cells and differentiation into beta cells were assessed using immunohistochemistry.ResultsRe-aggregation of the pancreatic cells before transplantation improved engraftment of the cells and facilitated neovascularization of the graft. Right before transplantation, pancreatic cells that were transfected with pEBVHGF and then re-aggregated showed ductal cell marker expression. However, ductal cells disappeared and the cells underwent fibrosis in a diabetes mouse model two to five weeks after transplantation; these mice also did not show controlled blood glucose levels. Furthermore, pancreatic cells transplanted into nude mice with normal blood glucose showed poor graft survival regardless of the type of transfected plasmid (pCEP4, pHGF, or pEBVHGF).ConclusionFor clinical application of transfected neonatal porcine pancreatic cells, further studies are required to develop methods of overcoming the damage for the cells caused by repeated transfection and to re-aggregate them into islet-like structures.

In this study, we established a radiodermatitis animal model and investigated the change in immune cell proportions in the secondary lymphoid organs. The cells responsible for the increased transforming growth factor-β1 (TGF-β1) and interleukin-10 (IL-10) production in the lesions following irradiation were also investigated. The radiodermatitis model was constructed by locally exposing the posterior dorsal region of hairless-1 (HR-1) mice to 10 Gy electron (E)-ray/day for six consecutive days. The change in immune cell proportions was analyzed by FACS. Immunohistochemistry was carried out to detect the expression of cytokines and cell-specific markers in the skin. The proportions of antigen-presenting cells, T cells, and B cells in the lymph nodes and spleen were affected by E-irradiation. After irradiation, TGF-β1 and IL-17 were co-localized in the papillary region of the dermis with keratin-14 (K-14)-positive cells rather than with regulatory T cells (Treg). IL-10 was not co-stained with Treg, T helper 17 (Th17) cells, dendritic cells, or macrophages. Our data indicate that TGF-β1 is over-expressed mainly by proliferated keratinocytes in the lesions of a radiodermatitis animal model.

Epstein-Barr virus (EBV)-encoded small non-coding RNAs (EBERs) are abundantly expressed in various EBVassociated malignancies, and play critical roles in cell proliferation, tumorigenesis, and apoptosis resistance. However, the mechanism how EBERs regulate cell function awaits further clarification. In this study, we investigated the effect of EBERs on the expression of cellular microRNA (miRNA) and mRNA expression. To test the effect of EBERs while unaffected by other EBV genes, we used EBERs-deleted recombinant EBV infected Burkitt's lymphoma cell line (Akata(+)EBERs(-)) as well as EBV-infected (Akata(+)) and EBV uninfected (Akata(-)) cell lines. They all have the same genetic backgrounds. First, 15 different cellular miRNAs which have reverse complementary sequences to EBERs and have reported targets were selected by bioinformatics analysis. When RT-PCR was carried out for the 16 miRNAs using RNAs from Akata(+), Akata(-), and Akata(+)EBERs(-) cells, hsa-miR-7-5p was the only one showing downregulated expression in Akata(+) than in Akata(-) and Akata(+)EBERs(-) cells. Bioinformatics and mRNA microarray analyses for Akata(+), Akata(-), and Akata(+)EBERs(-) cell lines were then carried out to predict putative targets of hsa-miR-7-5p. Among the 6 predicted targets of hsa-miR-7-5p, only low density lipoprotein receptor-related protein 6 (LRP6) was up-regulated in EBERs-expressing cells when tested by RT-PCR and Western blot. However, luciferase reporter assay showed that the 3'-UTR of LRP6 was not directly targeted by hsa-miR-7-5p. Our data suggest that both hsa-miR-7-5p and LRP6 are regulated by EBERs in Akata cells, and these genes may partly mediate the tumorigenic function of EBERs in Burkitt's lymphoma.