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Islet transplantation is a promising treatment for type 1 diabetes (T1D), yet the low donor pool, poor islet engraftment, and life-long immunosuppression prevent it from becoming the standard of care. Human embryonic stem cell (hESC)-derived pancreatic cells could eliminate donor shortages, but interventions to improve graft survival are needed. Here, we enhanced subcutaneous engraftment by employing a unique vascularization strategy based on ready-made microvessels (MVs) isolated from the adipose tissue. This resulted in improved cell survival and effective glucose response of both human islets and hESC-derived pancreatic cells, which ameliorated preexisting diabetes in three mouse models of T1D.

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In order to harness the potential of pluripotent stem cells, we need to understand how to differentiate them to our target cell types. Here, we developed a protocol to differentiate mouse embryonic stem cells (ESCs) to renal progenitors in a step-wise manner. Microarrays were used to track the transcriptional changes at each stage of differentiation and we observed that genes associated with metanephros, ureteric bud, and blood vessel development were significantly upregulated as the cells differentiated towards renal progenitors. Priming the ESCs and optimizing seeding cell density and growth factor concentrations helped improve differentiation efficiency. Organoids were used to determine the developmental potential of the renal progenitor cells. Aggregated renal progenitors gave rise to organoids consisting of LTL+/E-cadherin+ proximal tubules, cytokeratin+ ureteric bud-derived tubules, and extracellular matrix proteins secreted by the cells themselves. Over-expression of key kidney developmental genes, Pax2, Six1, Eya1, and Hox11 paralogs, during differentiation did not improve differentiation efficiency. Altogether, we developed a protocol to differentiate mouse ESCs in a manner that recapitulates embryonic kidney development and showed that precise gene regulation is essential for proper differentiation to occur.

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INTRODUCTION: The human placenta is accessible in early developmental stages and affords a unique opportunity to investigate human organogenesis and the dynamics of transitory cell populations in human placenta development. METHODS: The cell surface proteomic profile of early trophoblast cells of first trimester human placentas was quantified using a high throughput flow cytometry screen of 370 Cluster of Differentiation (CD) antigens. Targeted investigation of candidate trophoblast progenitor populations was done through immunohistochemistry, multi-color flow cytometry, and genome wide expression analysis. RESULTS: Using a novel batch correction and normalization methodology, we identified 23 increasing and 13 decreasing markers of dynamic populations between the week 6 and week 10 of placenta development. We identified and characterized two transient populations expressing either EpCAM (CD326) or CDCP1 (CD318). Immunohistochemistry revealed these CD antigens are expressed by discrete cells with EpCAM localized to the proximal villi columns and CDCP1 to distal columns. Flow analysis confirmed independence of these populations and identified EpCAM cells as positive for EGFR. Microarray analysis indicated EpCAM+/EGFR+ and EFGR + cells showed high degree of gene expression similarities to villus cytotrophoblast but loss of EpCAM expression was concomitant with exit from the cell cycle. Similarly, CDCP1 positive trophoblast are enriched in cell cycle gene sets and expressed genes with significant similarity to extravillous cytotrophoblast. DISCUSSION: Our study indicates at least two distinct subpopulations of cytotrophoblasts exist in the early first trimester within the column that likely maintains pools of actively dividing progenitor cells giving rise to the developing placenta villous tree.

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