1: Endocrinology. 2005 Mar;146(3):1025-34. Epub 2004 Dec 16. Minireview: transcriptional regulation in pancreatic development. Habener JF, Kemp DM, Thomas MK. Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Howard Hughes Medical Institute, Harvard Medical School, 55 Fruit Street, WEL320, Boston, Massachusetts 02114, USA. jhabener@partners.org Considerable progress has been made in the understanding of the sequential activation of signal transduction pathways and the expression of transcription factors during pancreas development. Much of this understanding has been obtained by analyses of the phenotypes of mice in which the expression of key genes has been disrupted (knockout mice). Knockout of the genes for Pdx1, Hlxb9, Isl1, or Hex results in an arrest of pancreas development at a very early stage (embryonic d 8-9). Disruption of genes encoding components of the Notch signaling pathway, e.g. Hes1 or neurogenin-3, abrogates development of the endocrine pancreas (islets of Langerhans). Disruption of transcription factor genes expressed more downstream in the developmental cascade (Beta2/NeuroD, Pax4, NKx2.2, and Nkx6.1) curtails the formation of insulin-producing beta-cells. An understanding of the importance of transcription factor genes during pancreas development has provided insights into the pathogenesis of diabetes, in which the mass of insulin-producing beta-cells is reduced. Publication Types: Review Review, Tutorial PMID: 15604203 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 2: Pancreas. 2004 Oct;29(3):e64-76. Redox-mediated enrichment of self-renewing adult human pancreatic cells that possess endocrine differentiation potential. Linning KD, Tai MH, Madhukar BV, Chang CC, Reed DN Jr, Ferber S, Trosko JE, Olson LK. Department of Physiology, Michigan State University, East Lansing, Michigan 48824, USA. OBJECTIVES: The limited availability of transplantable human islets has stimulated the development of methods needed to isolate adult pancreatic stem/progenitor cells capable of self-renewal and endocrine differentiation. The objective of this study was to determine whether modulation of intracellular redox state with N-acetyl-L-cysteine (NAC) would allow for the propagation of pancreatic stem/progenitor cells from adult human pancreatic tissue. METHODS: Cells were propagated from human pancreatic tissue using a serum-free, low-calcium medium supplemented with NAC and tested for their ability to differentiate when cultured under different growth conditions. RESULTS: Human pancreatic cell (HPC) cultures coexpressed alpha-amylase, albumin, vimentin, and nestin. The HPC cultures, however, did not express other genes associated with differentiated pancreatic exocrine, duct, or endocrine cells. A number of transcription factors involved in endocrine cell development including Beta 2, Islet-1, Nkx6.1, Pax4, and Pax6 were expressed at variable levels in HPC cultures. In contrast, pancreatic duodenal homeobox factor 1 (Pdx-1) expression was extremely low and at times undetectable. Overexpression of Pdx-1 in HPC cultures stimulated somatostatin, glucagon, and carbonic anhydrase expression but had no effect on insulin gene expression. HPC cultures could form 3-dimensional islet-like cell aggregates, and this was associated with expression of somatostatin and glucagon but not insulin. Cultivation of HPCs in a differentiation medium supplemented with nicotinamide, exendin-4, and/or LY294002, an inhibitor of phosphatidylinositol-3 kinase, stimulated expression of insulin mRNA and protein. CONCLUSION: These data support the use of intracellular redox modulation for the enrichment of pancreatic stem/progenitor cells capable of self-renewal and endocrine differentiation. PMID: 15367896 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 3: J Cell Biol. 2002 Oct 28;159(2):303-12. Epub 2002 Oct 28. Recapitulation of embryonic neuroendocrine differentiation in adult human pancreatic duct cells expressing neurogenin 3. Heremans Y, Van De Casteele M, in't Veld P, Gradwohl G, Serup P, Madsen O, Pipeleers D, Heimberg H. Diabetes Research Center, Brussels Free University (VUB), Laarbeeklaan 103, B-1090 Brussels, Belgium. Regulatory proteins have been identified in embryonic development of the endocrine pancreas. It is unknown whether these factors can also play a role in the formation of pancreatic endocrine cells from postnatal nonendocrine cells. The present study demonstrates that adult human pancreatic duct cells can be converted into insulin-expressing cells after ectopic, adenovirus-mediated expression of the class B basic helix-loop-helix factor neurogenin 3 (ngn3), which is a critical factor in embryogenesis of the mouse endocrine pancreas. Infection with adenovirus ngn3 (Adngn3) induced gene and/or protein expression of NeuroD/beta2, Pax4, Nkx2.2, Pax6, and Nkx6.1, all known to be essential for beta-cell differentiation in mouse embryos. Expression of ngn3 in adult human duct cells induced Notch ligands Dll1 and Dll4 and neuroendocrine- and beta-cell-specific markers: it increased the percentage of synaptophysin- and insulin-positive cells 15-fold in ngn3-infected versus control cells. Infection with NeuroD/beta2 (a downstream target of ngn3) induced similar effects. These data indicate that the Delta-Notch pathway, which controls embryonic development of the mouse endocrine pancreas, can also operate in adult human duct cells driving them to a neuroendocrine phenotype with the formation of insulin-expressing cells. PMID: 12403815 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 4: Mol Cell Endocrinol. 2000 Jul 25;165(1-2):41-9. Transcription factor expression and hormone production in pancreatic AR42J cells. Palgi J, Stumpf E, Otonkoski T. Transplantation Laboratory, Haartman Institute and the Hospital for Children and Adolescents, University of Helsinki, PO Box 21 (Haartmaninkatu 3), FIN-00014, Helsinki, Finland. jaan.palgi@helsinki.fi AR42J is an exocrine pancreatic cell line that has been reported to differentiate towards an endocrine phenotype when stimulated with various growth factors, such as activin A, hepatocyte growth factor (HGF), betacellulin or glucagon-like peptide 1. In our experiments, AR42J-B13 cells differentiated morphologically in response to the growth factor treatment as reported previously. However, they failed to express the insulin gene. We found that the cells did not express several transcription factors known to be found in the beta-cell, including Nkx6.1, isl-1, Pax4 and Pax6. In addition, the mRNA level for pdx-1 and Nkx2.2 were very low in comparison to the insulinoma cell lines INS-1 and RINm5F. However, some transcription factors typically found in beta-cells and neuroendocrine cells were expressed also in the AR42J-B13 cells. These included BETA2/NeuroD, HNF1alpha, C/EBPbeta and IA-1. Unlike the insulinoma cells, AR42J cells expressed the exocrine transcription factor p48. In order to induce endocrine differentiation, we transfected the AR42J-B13 cells with the full length cDNAs of isl-1, Nkx6.1, Nkx2.2 and pdx-1 under the control of the CMV promoter, both separately and in combinations. The expression of Nkx2.2 led consistently to the appearance of pancreatic polypeptide but not insulin, glucagon or somatostatin mRNA. The PP mRNA expression in Nkx2.2 cDNA transfected cells was independent of the growth factor treatment used for differentiating AR42J cells. In conclusion, the AR42J-B13 line possesses some features of a pancreatic neuroendocrine cell. However, we were unable to confirm the capacity of these cells to differentiate into insulin-producing cells. Our results indicate that Nkx2.2 plays a role in the transcriptional regulation of PP expression. PMID: 10940482 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 5: FEBS Lett. 1999 Nov 19;461(3):287-94. Cloning and DNA-binding properties of the rat pancreatic beta-cell-specific factor Nkx6.1. Jorgensen MC, Vestergard Petersen H, Ericson J, Madsen OD, Serup P. Department of Developmental Biology, Hagedorn Research Institute, Niels Steensensvej 6, DK-2820, Gentofte, Denmark. The homeodomain (HD) protein Nkx6.1 is the most beta-cell-specific transcription factor known in the pancreas and its function is critical for the formation of the insulin-producing beta-cells. However, the target genes, DNA-binding site, and transcriptional properties of Nkx6.1 are unknown. Using in vitro binding site selection we have identified the DNA sequence of the Nkx6.1 binding site to be TTAATTG/A. A reporter plasmid containing four copies of this sequence is activated by an Nkx6.1HD/VP16 fusion construct. Full-length Nkx6.1 fails to activate this reporter plasmid in spite of robust interaction with the binding site in vitro. Stable expression of Nkx6.1 in the glucagon-producing alpha-cell-like MSL-G-AN cells induces expression of the endogenous insulin gene in a subset of the cell population. The expression of other known beta-cell-specific factors such as Pax4, Pax6, Pdx1, GLUT2 and GLP1-R is unchanged by the introduction of Nkx6.1. PMID: 10567713 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 6: Int J Mol Med. 1999 Mar;3(3):247-61. Development of pancreatic islets (review). Yamaoka T, Itakura M. Otsuka Department of Clinical and Molecular Nutrition, School of Medicine, The University of Tokushima, Tokushima 770-8503, Japan. Recent studies have revealed that islet cells differentiate from the epithelial cells of primitive pancreatic ducts during embryogenesis, and can regenerate in response to the loss of islet cells even in adult pancreas. The ability of islet cells to regenerate raises the possibility that impaired and decreased islets of diabetic patients can be restored. In this review, factors regulating islet development including differentiation factors (Shh, activin, follistatin, and TGF alpha), transcriptional factors (PDX1, Isl1, Pax4, Pax6, Nkx2.2, Nkx6.1, BETA2, and HNF), growth factors (the EGF family, HGF, IGF-I, IGF-II, Reg, INGAP, PDGF, FGF, VEGF, and NGF), hormones (insulin, the GH family, PTHrP, TRH, and gastrin), and cell adhesion molecules (N-CAM and cadherins) are described after a short introduction and an outline of pancreatic development. Publication Types: Review Review, Tutorial PMID: 10028048 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 7: Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8654-9. Targeted oncogenesis of hormone-negative pancreatic islet progenitor cells. Jetton TL, Moates JM, Lindner J, Wright CV, Magnuson MA. Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615, USA. Transgenic mice containing an upstream glucokinase (betaGK) promoter- simian virus 40 T antigen (Tag) fusion gene develop neuroendocrine tumors primarily in the pancreas, gut, and pituitary. Pancreatic tumors from a line with delayed tumorigenesis were of two different types: insulinomas and noninsulinomas. The noninsulinomas are often periductal in location, express none of the four major islet peptide hormones, Glut-2, Pdx1, tyrosine hydroxylase, Pax4, Pax6, or Nkx6.1, but do express glucokinase, Sur1, Isl1, Hnf3beta, Hnf6, Beta2/NeuroD, and Nkx2.2. Cells from two different noninsulinoma tumors, when adapted to culture, began to express either insulin, glucagon, or somatostatin. Given the partial gene expression repertoire of the noninsulinoma tumors, their apparent periductal origin, and the ability of these cells to partially cytodifferentiate in culture, we suggest that these tumors are derived from islet progenitor cells. Thus, betaGK-Tag transgenic mice provide a new model system for studying the events that occur during both islet cell neogenesis and normal embryonic development. PMID: 9671733 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------