Mechanisms Inducing Differentiation of Adult Islet Progenitor-Like Cells into Functional Islet-Like Organoids

Carly M. Darden^1,2Jayachandra Kuncha¹Jeffrey Kirkland²Jordan Mattke¹Srividya Vasu¹Prathab Balaji Saravanan¹Bashoo Naziruddin²Michael C. Lawrence^1*

• ¹Baylor Scott & White Research Institute (BSWRI), Dallas, United States
• ²Baylor University Medical Center, Dallas, United States

Adult pancreatic tissue contains cell populations with latent regenerative potential, but the processes governing their expansion and differentiation into endocrine lineages remain unclear. Here, we isolated and expanded adult human pancreatic cells obtained from donor tissue and analyzed their lineage potential using single-cell RNA sequencing, flow cytometry, and functional assays. A subpopulation of CD9⁺ PROCR⁺ RGS16⁺ cells, termed islet progenitor-like cells (IPCs), exhibited robust proliferative capacity and, upon differentiation, formed insulin-and glucagon-secreting organoids. Treatment of IPCs with the small molecule ISX9 induced expression of key transcription factors RFX6 and NEUROD1 through calcium-dependent chromatin remodeling mediated by NFAT recruitment of p300 and displacement of histone deacetylases (HDAC1–3). Pharmacologic inhibition of HDACs further enhanced IPC maturation and glucose-stimulated insulin secretion. These findings define the molecular and epigenetic mechanisms driving the expansion and differentiation of adult IPCs into functional islet-like organoids, providing a foundation for future regenerative approaches using adult pancreatic tissue as a renewable source for endocrine cell replacement.