Expression DATA from E11.5 pancreatic buds treated with I-BET151 or JQ1 for 24h

Bromodomain and Extra-terminal (BET) proteins are epigenetic readers that interact with acetylated lysines of histone tails. Recent studies have demonstrated their role in cancer progression, as they recruit key components of the transcriptional machinery to modulate gene expression. However, their role during embryonic development of the pancreas has never been studied. Using mouse embryonic pancreatic explants and human IPSC, we show that inhibition of BET proteins with either I-BET151 or JQ1 dramatically enhances the number of neurogenin3 (NEUROG3) endocrine progenitors, leading to an increased number of endocrine cells in the pancreatic explants. Despite inducing several β cell markers, BETi also strongly down-regulated Ins1 expression in developed explants and adult β cells. However, removal of BETi from explants prior to β cell development, as NEUROG3 expression peaks, further led to enhanced β cell development with higher expression of insulin and maturation markers UCN3 and MAFA. Altogether, these results show that BET proteins play a major role in the pancreas endocrine differentiation. Furthermore, they highlight the potential use of BETi to improve β cell replacement therapies. Mouse embryonic (E11.5) pancreatic buds were cultured for 24h in presence of 0.1% DMSO (CTRL) ro 500nM I-BET151 or 100nM JQ1