MON-726 Modifications of FOXO1 and GATA4-NKX2.5 Signaling Induce Human Enteroendocrine Differentiation

Enteroendocrine (EE) cells are the most abundant hormone-producing cells in the human body and are vital for metabolism, as well as intestinal and pancreatic function. They have been implicated in the pathogenesis of multiple diseases including diabetes mellitus. Although recent studies have identified multiple signaling pathways (including Wnt, MAPK, BMP and Notch) that can induce low levels of EE cell differentiation, the production of functional human EE cells in vitro remains challenging, making their study and therapeutic utilization difficult. To improve this, we employed the human intestinal organoid culturing system, as it mimics intestinal epithelial homeostasis, allowing for differentiation of multiple epithelial cell types. Using a small scale, directed screen, we targeted multiple transcriptional regulators, using small molecules known to control pancreatic and intestinal development, and hormone production. We chose small molecules instead of gene editing tools to avoid the potential pitfall of off-target mutagenesis. We found that inhibition of FoxO1 in our organoid culture led to an increase in EE cell differentiation as assessed by EE-specific gene expression, with a 5-10 fold upregulation in expression of ChgA, NeuroD1, and Neurog3 compared to whole mucosal biopsies (P