Ex vivo expansion and differentiation of human and mouse fetal pancreas progenitors are modulated by Epidermal Growth Factor

A comparative analysis of mouse and human pancreas development may reveal common mechanisms that control key steps as organ morphogenesis and cell proliferation and differentiation. More specifically, understanding beta cell development remains an issue despite recent progress related to their generation from human embryonic (ES) and induced pluripotent stem cells (iPS). Here we use an integrated approach including prospective isolation, organ culture, and characterization of intermediate stages and report that cells from human and mouse fetal pancreas can be expanded long-term and give rise to hollow duct-like structures in 3D cultures. The expanded cells express a combination of markers (E-Cadherin, PDX1, NKX6-1, SOX9, and HNF1β) that reveals pancreas progenitor identity. Proliferation of embryonic progenitors was stimulated by the Wnt agonist R-Spondin1 (RSPO1), FGF10 and EGF. This combination of growth factors allowed maintaining human fetal pancreas progenitors in culture for many passages, a finding not reported previously. Importantly, in the absence of EGF, proliferation was reduced while endocrine differentiation was significantly enhanced. We conclude that modulation of EGF-signaling affects in vitro expansion and differentiation of progenitors from embryonic pancreas of both mice and man.