<i>Neurogenin 3</i> is essential for the proper specification of gastric enteroendocrine cells and the maintenance of gastric epithelial cell identity

143

142

Prospective isolation and characterization of progenitor cells is a paradigmatic strategy for studies of organ development. However, extraction of viable cells, fractionation of lineages, and in vitro analysis of progenitors from the fetal pancreas in experimental organisms like mice has proved challenging and has not yet been reported for human fetal pancreas. Here, we report isolation of pancreatic islet progenitor cells from fetal mice by FACS. Monoclonal antibodies that recognize cell-surface proteins on candidate stem cells in brain, skin, and other organs enabled separation of major pancreatic cell lineages and isolation of native pancreatic cells expressing neurogenin 3, an established marker of islet progenitors. New in vitro cell culture methods permitted isolated mouse islet progenitors to develop into hormone-expressing endocrine cells. Insulin-producing cells derived in vitro required or expressed factors that regulate fetal ␤ cell differentiation; thus, the genetic programs normally controlling in vivo mouse islet development are similarly required in our system. Moreover, antibodies that recognize conserved orthologous cell-surface epitopes in human fetal pancreas allowed FACS-based enrichment of candidate islet progenitor cells expressing neurogenin 3. Our studies reveal previously undescribed strategies for prospective purification and analysis of pancreatic endocrine progenitor cells that should accelerate studies of islet development and replacement.diabetes ͉ pancreas ͉ stem/progenitor cell ͉ neurogenin 3 ͉ CD133

Section: Isolation Of a Cd133 ؉ Cd49f High Ngn3 ؊ Pancreatic Compartmmentioning

confidence: 99%

Conserved markers of fetal pancreatic epithelium permit prospective isolation of islet progenitor cells by FACS

Sugiyama

Rodriguez

McLean

et al. 2007

143

142

“…The above findings led us to examine enhanced green fluorescent protein (EGFP) expression in the pancreata of Neurog3 EGFP knock-in mice (19), a line in which EGFP expression was reportedly absent in the adult pancreas (13,20). By using confocal microscopy, weak yet visible EGFP fluorescence (enriched in nuclei) was seen in a large number of islet cells from Neurog3 EGFP animals at 2, 4, and 6 months of age (Fig.…”

Section: Knock-in Reporter Mice Reveal Neurog3 Expression In Adult Ismentioning

confidence: 99%

Sustained Neurog3 expression in hormone-expressing islet cells is required for endocrine maturation and function

Wang¹,

Jensen

Seymour

et al. 2009

147

143

Neurog3 (Neurogenin 3 or Ngn3) is both necessary and sufficient to induce endocrine islet cell differentiation from embryonic pancreatic progenitors. Since robust Neurog3 expression has not been detected in hormone-expressing cells, Neurog3 is used as an endocrine progenitor marker and regarded as dispensable for the function of differentiated islet cells. Here we used 3 independent lines of Neurog3 knock-in reporter mice and mRNA/protein-based assays to examine Neurog3 expression in hormone-expressing islet cells. Neurog3 mRNA and protein are detected in hormoneproducing cells at both embryonic and adult stages. Significantly, inactivating Neurog3 in insulin-expressing ␤ cells at embryonic stages or in Pdx1-expressing islet cells in adults impairs endocrine function, a phenotype that is accompanied by reduced expression of several Neurog3 target genes that are essential for islet cell differentiation, maturation, and function. These findings demonstrate that Neurog3 is required not only for initiating endocrine cell differentiation, but also for promoting islet cell maturation and maintaining islet function.endocrine progenitor ͉ maintenance ͉ pancreas ͉ diabetes ͉ sugar metabolism

“…Multiple Notch receptors and ligands are expressed in the intestine (7,8), and three Notch-regulated genes have intestinal phenotypes. Specifically, inactivation of Neurogenin3 (Ngn3) or Hes1 alters endocrine differentiation (9)(10)(11), whereas inactivation of Math1 results in the absence of all secretory cell types (1 (12). Third, does Notch function in the adult intestine?…”

mentioning

confidence: 99%

Direct regulation of intestinal fate by Notch

Stanger

Datar

Murtaugh

et al. 2005

268

216

The signals that maintain the proper balance between adult intestinal cell types are poorly understood. Loss-of-function studies have implicated the Notch pathway in the regulation of intestinal fate during development. However, it is unknown whether Notch has a role in maintaining the balance of different cell types in the adult intestine and whether it acts reversibly. To determine whether Notch has a direct effect on intestinal development and adult intestinal cell turnover, we have used a gain-of-function approach to activate Notch. Ectopic Notch signaling in adult intestinal progenitor cells leads to a bias against secretory fates, whereas ectopic Notch activation in the embryonic foregut results in reversible defects in villus morphogenesis and loss of the proliferative progenitor compartment. We conclude that Notch regulates adult intestinal development by controlling the balance between secretory and absorptive cell types. In the embryo, Notch activation perturbs morphogenesis, possibly through effects on stem or progenitor cells.differentiation ͉ intestine ͉ lineage ͉ stem cells