Differentiation of Mesenchymal Stem Cells Derived from Pancreatic Islets and Bone Marrow into Islet-Like Cell Phenotype

BACKGROUND:Regarding regenerative medicine for diabetes, accessible sources of Mesenchymal Stem Cells (MSCs) for induction of insular beta cell differentiation may be as important as mastering the differentiation process itself. METHODOLOGY/PRINCIPAL FINDINGS:In the present work, stem cells from pancreatic islets (human islet-mesenchymal stem cells, HI-MSCs) and from human bone marrow (bone marrow mesenchymal stem cells, BM-MSCs) were cultured in custom-made serum-free medium, using suitable conditions in order to induce differentiation into Islet-like Cells (ILCs). HI-MSCs and BM-MSCs were positive for the MSC markers CD105, CD73, CD90, CD29. Following this induction, HI-MSC and BM-MSC formed evident islet-like structures in the culture flasks. To investigate functional modifications after induction to ILCs, ultrastructural analysis and immunofluorescence were performed. PDX1 (pancreatic duodenal homeobox gene-1), insulin, C peptide and Glut-2 were detected in HI-ILCs whereas BM-ILCs only expressed Glut-2 and insulin. Insulin was also detected in the culture medium following glucose stimulation, confirming an initial differentiation that resulted in glucose-sensitive endocrine secretion. In order to identify proteins that were modified following differentiation from basal MSC (HI-MSCs and BM-MSCs) to their HI-ILCs and BM-ILCs counterparts, proteomic analysis was performed. Three new proteins (APOA1, ATL2 and SODM) were present in both ILC types, while other detected proteins were verified to be unique to the single individual differentiated cells lines. Hierarchical analysis underscored the limited similarities between HI-MSCs and BM-MSCs after induction of differentiation, and the persistence of relevant differences related to cells of different origin. CONCLUSIONS/SIGNIFICANCE:Proteomic analysis highlighted differences in the MSCs according to site of origin, reflecting spontaneous differentiation and commitment. A more detailed understanding of protein assets may provide insights required to master the differentiation process of HI-MSCs to functional beta cells based only upon culture conditioning. These findings may open new strategies for the clinical use of BM-MSCs in diabetes

Allergen induced gene expression of airway epithelial cells shows a possible role for TNF-alpha

BACKGROUND: Epithelium is more than a physical barrier for pathogens and allergens, as it is also capable of producing mediators in response to these environmental factors. Some of these mediators have an immuno-modulatory function, suggesting that epithelium is an active component of the immune response. Here, we fully characterize the expression profile of airway epithelial cells in response to house dust mite (HDM) allergen. METHODS: H292 cells were exposed to HDM extract for 24 h, RNA and supernatant was used for microarray analysis and multiplex enzyme-linked immunosorbent assay (ELISA) respectively. RESULTS: A total of 38,500 genes, 813 were differentially expressed by more than twofold and 116 even more than fivefold. Interestingly, among the most up-regulated genes, a large number are involved in cell-to-cell communication. These include chemokines (CCL-8 and -20, CXCL-1, -2 and -3), cytokines (IL-1alpha, -6 and -11), anti-inflammatory factors [PTX-3, interleukin (IL)-13Ralpha, tumour necrosis factor (TNF)-alphaIP3], and factors that are involved in repair of the mucosal tissue (LOXL-2, NID-2, HBEGF, MUC-5AC and MUC-5B). Pathway analysis showed that a number of these genes are transcriptionally regulated by TNF-alpha, which we could detect by quantitative polymerase chain reaction at earlier time points after HDM exposure. In addition, we could detect increased protein levels for TNF-alpha, IL-6, IL8, granulocyte-macrophage colony-stimulating factor, granulocyte colony stimulating factor and interferon (IFN)-gamma using ELISA. CONCLUSION: Our data show that a broad range of mediators produced upon allergen exposure by these mediators' epithelial cells can participate in the immune response via recruitment and activation of cells of the immune syste