Identification and Characterization of Adult Islet Pancridia Cells Capable of Differentiating into Islet Organoids

Multipotent progenitor-like cells have been identified in the adult pancreas under various physiological and pathological conditions. Here, we identify and characterize a subset of adult pancreas-derived cells, termed islet pancridia cells (IPCs), that can be expanded in vitro and retain the potential for endocrine differentiation and islet cell function. Single-cell RNA sequencing of expanded pancridia revealed transcriptomic profiles resembling immature beta cells, enriched with markers of epithelial-mesenchymal transition. A CD9⁺, PROCR⁺ subpopulation of IPCs formed IPC clusters marked by restricted expression of RGS16, a known islet progenitor marker. In vivo, co-transplantation of expanded IPCs with a subtherapeutic dose of islets significantly improved graft function and partially restored native pancreatic endocrine activity in streptozotocin-induced diabetic mice. In vitro, treatment of RGS16⁺ IPC clusters with the small molecule ISX9 induced differentiation into islet organoids that co-expressed and secreted insulin and glucagon. ISX9-mediated differentiation was driven by calcineurin/NFAT-dependent recruitment of the histone acetyltransferase p300 and displacement of histone deacetylases (HDACs) at the RFX6 and NEUROD1 promoters. Pre-treatment with the HDAC inhibitor ITF2357 further enhanced islet cell differentiation by promoting chromatin remodeling and facilitating NFAT-targeted recruitment of p300. These findings uncover calcium-dependent and epigenetic mechanisms that regulate the differentiation of multipotent CD9⁺, PROCR⁺, RGS16⁺ IPCs into functional islet organoids and offer potential strategies for regenerating islet cell mass to treat diabetes.