223-OR: Characterization of Regenerative Adult Islet Progenitor Cells from Human Pancreatic Tissue

Introduction & Objective: To identify and characterize expandable islet progenitor cells in human pancreatic tissue capable of regenerating islet organoids in vitro and in vivo. Methods: Single cell RNA-sequencing was performed on dissociated pancreatic tissue from normal human pancreas and pancreatitis to identify islet progenitor cell populations, gene signatures, and unique markers expressed in vitro and in vivo. Islet progenitors were validated by QPCR and flow cytometry. Islet progenitor cells were isolated by flow-sorting and expanded to produce functional islet-like organoids. Undifferentiated islet progenitor cells and differentiated islet-like organoids were transplanted into STZ-induced diabetic nude mice to assess islet function. Grafts and native pancreas were assessed for expression of islet organoids. Results: A total of 9807 cells were analyzed and multiple cell types were identified and matched to pancreatic cell subtypes, including activated stellate cells (86%), ductal cell (9.2%), beta cell (3.8%), and alpha cell (0.5%). Human islet progenitors were identified expressing stem-cell marker Procr, immature beta-cell marker CD9, and islet endocrine progenitor marker RGS16. These Procr+, CD9+, RGS16+ cells also expressed ductal epithelial, stellate, and mesenchymal cell markers indicative of epithelial-mesenchymal transition. Undifferentiated islet progenitor cells could migrate to the damaged mouse pancreas to produce human islet organoids in vivo within 28 days post-transplantation. Islet progenitor cells could be differentiated to produce and release insulin and glucagon in vitro and restore islet cell function in vivo. Conclusion: Procr+, CD9+, RGS16+ islet progenitor cells expanded from human pancreatic tissue retain regenerative properties to produce functional islet cell organoids in vitro and in vivo for potential use in islet cell replacement therapy or strategies to regenerate islet cells in the native pancreas.