The Experts below are selected from a list of 2187 Experts worldwide ranked by ideXlab platform
Christopher V.e. Wright - One of the best experts on this subject based on the ideXlab platform.
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rock nmmyoii notch and NEUROG3 gene dosage link epithelial morphogenesis with cell fate in the pancreatic endocrine progenitor niche
Development, 2018Co-Authors: Eric D Bankaitis, Matthew E Bechard, Mark A Magnuson, Christopher V.e. WrightAbstract:ABSTRACT During mouse pancreas organogenesis, endocrine cells are born from progenitors residing in an epithelial plexus niche. After a period in a lineage-primed NEUROG3LO state, progenitors become endocrine committed via upregulation of NEUROG3. We find that the NEUROG3LO to NEUROG3HI transition is associated with distinct stages of an epithelial egression process: narrowing the apical surface of the cell, basalward cell movement and eventual cell-rear detachment from the apical lumen surface to allow clustering as nascent islets under the basement membrane. Apical narrowing, basalward movement and NEUROG3 transcriptional upregulation still occur without NEUROG3 protein, suggesting that morphogenetic cues deployed within the plexus initiate endocrine commitment upstream or independently of NEUROG3. NEUROG3 is required for cell-rear detachment and complete endocrine-cell birth. The ROCK-nmMyoII pathway coordinates epithelial-cell morphogenesis and the progression through NEUROG3-expressing states. NmMyoII is necessary for apical narrowing, basalward cell displacement and NEUROG3 upregulation, but all three are limited by ROCK activity. We propose that ROCK-nmMyoII activity, NEUROG3 gene-dose and Notch signaling integrate endocrine fate allocation with epithelial plexus growth and morphogenesis, representing a feedback control circuit that coordinates morphogenesis with lineage diversification in the endocrine-birth niche.
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fucci tracking shows cell cycle dependent NEUROG3 variation in pancreatic progenitors
Genesis, 2017Co-Authors: Matthew E Bechard, Eric D Bankaitis, Alessandro Ustione, David W Piston, Mark A Magnuson, Christopher V.e. WrightAbstract:During pancreas organogenesis, NEUROG3HI endocrine-committing cells are generated from a population of Sox9+ mitotic progenitors with only a low level of NEUROG3 transcriptional activity (NEUROG3TA.LO ). Low-level NEUROG3 protein, in NEUROG3TA.LO cells, is required to maintain their mitotic endocrine-lineage-primed status. Herein, we describe a NEUROG3-driven FUCCI cell-cycle reporter (NEUROG3P2A.FUCCI ) derived from a NEUROG3 BAC transgenic reporter that functions as a loxed cassette acceptor (LCA). In cycling Sox9+ NEUROG3TA.LO progenitors, the majority of cells in S-G2 -M phases have undetectable levels of NEUROG3 with increased expression of endocrine progenitor markers, while those in G1 have low NEUROG3 levels with increased expression of endocrine differentiation markers. These findings support a model in which variations in NEUROG3 protein levels are coordinated with cell-cycle phase progression in NEUROG3TA.LO progenitors with entrance into G1 triggering a concerted effort, beyond increasing NEUROG3 levels, to maintain an endocrine-lineage-primed state by initiating expression of the downstream endocrine differentiation program prior to endocrine-commitment.
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fucci tracking shows that NEUROG3 levels vary with cell cycle phase in endocrine biased pancreatic progenitors
bioRxiv, 2017Co-Authors: Matthew E Bechard, Eric D Bankaitis, Alessandro Ustione, David W Piston, Mark A Magnuson, Christopher V.e. WrightAbstract:NEUROG3 HI endocrine-committing cells are generated from a population of Sox9 + mitotic progenitors with only a low level of NEUROG3 transcriptional activity ( NEUROG3 TA.LO ). Low-level NEUROG3 protein, in NEUROG3 TA.LO cells, is required to maintain their mitotic endocrine-lineage-primed status. Herein, we describe a NEUROG3 -driven FUCCI cell-cycle reporter ( NEUROG3 P2A.FUCCI ) derived from a NEUROG3 BAC transgenic reporter that functions as a loxed cassette acceptor (LCA). In cycling Sox9 + NEUROG3 TA.LO progenitors, the majority of cells in S-G 2 -M phases have undetectable levels of NEUROG3 with increased expression of endocrine progenitor markers, while those in G 1 have low NEUROG3 levels with increased expression of endocrine differentiation markers. These findings support a model in which variations in NEUROG3 protein levels are coordinated with cell-cycle phase progression in NEUROG3 TA.LO progenitors with entrance into G 1 triggering a concerted effort, beyond increasing NEUROG3 levels, to maintain an endocrine-lineage-primed state by initiating expression of the downstream endocrine differentiation program prior to endocrine-commitment.
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precommitment low level NEUROG3 expression defines a long lived mitotic endocrine biased progenitor pool that drives production of endocrine committed cells
Genes & Development, 2016Co-Authors: Matthew E Bechard, Eric D Bankaitis, Alessandro Ustione, David W Piston, Mark A Magnuson, Susan B Hipkens, Yuping Yang, Christopher V.e. WrightAbstract:The current model for endocrine cell specification in the pancreas invokes high-level production of the transcription factor Neurogenin 3 (NEUROG3) in Sox9(+) bipotent epithelial cells as the trigger for endocrine commitment, cell cycle exit, and rapid delamination toward proto-islet clusters. This model posits a transient NEUROG3 expression state and short epithelial residence period. We show, however, that a NEUROG3(TA.LO) cell population, defined as NEUROG3 transcriptionally active and Sox9(+) and often containing nonimmunodetectable NEUROG3 protein, has a relatively high mitotic index and prolonged epithelial residency. We propose that this endocrine-biased mitotic progenitor state is functionally separated from a pro-ductal pool and endows them with long-term capacity to make endocrine fate-directed progeny. A novel BAC transgenic NEUROG3 reporter detected two types of mitotic behavior in Sox9(+) NEUROG3(TA.LO) progenitors, associated with progenitor pool maintenance or derivation of endocrine-committed NEUROG3(HI) cells, respectively. Moreover, limiting NEUROG3 expression dramatically increased the proportional representation of Sox9(+) NEUROG3(TA.LO) progenitors, with a doubling of its mitotic index relative to normal NEUROG3 expression, suggesting that low NEUROG3 expression is a defining feature of this cycling endocrine-biased state. We propose that Sox9(+) NEUROG3(TA.LO) endocrine-biased progenitors feed production of NEUROG3(HI) endocrine-committed cells during pancreas organogenesis.
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Threshold-dependent cooperativity of Pdx1 and Oc1 in pancreatic progenitors establishes competency for endocrine differentiation and β-cell function
Cell Reports, 2016Co-Authors: Kathryn D. Henley, Christopher V.e. Wright, Diana E. Stanescu, Peter A. Kropp, Kyoung-jae Won, Doris A. Stoffers, Maureen GannonAbstract:Pdx1 and Oc1 are co-expressed in multipotent pancreatic progenitors and regulate the pro-endocrine gene NEUROG3. Their expression diverges in later organogenesis, with Oc1 absent from hormone+ cells and Pdx1 maintained in mature β cells. In a classical genetic test for cooperative functional interactions, we derived mice with combined Pdx1 and Oc1 heterozygosity. Endocrine development in double-heterozygous pancreata was normal at embryonic day (E)13.5, but defects in specification and differentiation were apparent at E15.5, the height of the second wave of differentiation. Pancreata from double heterozygotes showed alterations in the expression of genes crucial for β-cell development and function, decreased numbers and altered allocation of NEUROG3-expressing endocrine progenitors, and defective endocrine differentiation. Defects in islet gene expression and β-cell function persisted in double heterozygous neonates. These results suggest that Oc1 and Pdx1 cooperate prior to their divergence, in pancreatic progenitors, to allow for proper differentiation and functional maturation of β cells.
Palle Serup - One of the best experts on this subject based on the ideXlab platform.
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genome wide identification of hes1 target genes uncover novel roles for hes1 in pancreatic development
bioRxiv, 2018Co-Authors: K Lichtenberg H De, N S Funa, Nikolina Nakic, Danwei Huangfu, Jorge Ferrer, Palle SerupAbstract:Notch signalling and the downstream effector HES1 is required for multiple pancreatic cell fate choices during development, but the direct target genes remain poorly characterised. Here we identify direct HES1 target genes on a genome-wide scale using ChIP-seq and RNA-seq analyses combined with human embryonic stem cell (hESC) directed differentiation of CRISPR/Cas9-generated HES1 −/− mutant hESC lines. We found that HES1 binds to a distinct set of endocrine-specific genes, a set of genes encoding basic Helix-Loop-Helix (bHLH) proteins not normally expressed in the pancreas, genes in the Notch pathway, and the known HES1 target NEUROG3 . RNA-seq analysis of wild type, HES1 −/− , NEUROG3 −/− , and HES1 −/− NEUROG3 −/− mutant hESC lines allowed us to uncover NEUROG3-independent, direct HES1 target genes. Among the HES1 bound genes that were derepressed in HES1 −/− NEUROG3 −/− cells compared to NEUROG3 −/− cells, we found members of the endocrine-specific gene set, the Notch pathway genes DLL1 , DLL4 , and HEY1 , as well as the non-pancreatic bHLH genes ASCL1 and ATOH1 . We also found a large number of transcripts specific to the intestinal secretory lineage to be increased in HES1 −/− NEUROG3 −/− cells. Together, our data reveal that HES1 employs a multi-layered control of endocrine differentiation, controls Notch ligand expression independent of NEUROG3, and prevents initiation of ectopic intestinal transcriptional programmes in pancreas progenitors.
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Ptf1a-mediated control of Dll1 reveals an alternative to the lateral inhibition mechanism
Development, 2011Co-Authors: Jonas Ahnfelt-rønne, Ole D. Madsen, Christopher V.e. Wright, Mette C. Jørgensen, Rasmus Klinck, Jan N. Jensen, Ernst-martin Füchtbauer, Tye G. Deering, Raymond J. Macdonald, Palle SerupAbstract:NEUROG3-induced Dll1 expression in pancreatic endocrine progenitors ostensibly activates Hes1 expression via Notch and thereby represses NEUROG3 and endocrine differentiation in neighboring cells by lateral inhibition. Here we show in mouse that Dll1 and Hes1 expression deviate during regionalization of early endoderm, and later during early pancreas morphogenesis. At that time, Ptf1a activates Dll1 in multipotent pancreatic progenitor cells (MPCs), and Hes1 expression becomes Dll1 dependent over a brief time window. Moreover, Dll1, Hes1 and Dll1/Hes1 mutant phenotypes diverge during organ regionalization, become congruent at early bud stages, and then diverge again at late bud stages. Persistent pancreatic hypoplasia in Dll1 mutants after eliminating NEUROG3 expression and endocrine development, together with reduced proliferation of MPCs in both Dll1 and Hes1 mutants, reveals that the hypoplasia is caused by a growth defect rather than by progenitor depletion. Unexpectedly, we find that Hes1 is required to sustain Ptf1a expression, and in turn Dll1 expression in early MPCs. Our results show that Ptf1a-induced Dll1 expression stimulates MPC proliferation and pancreatic growth by maintaining Hes1 expression and Ptf1a protein levels.
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permanent neonatal diabetes and enteric anendocrinosis associated with biallelic mutations in NEUROG3
Diabetes, 2011Co-Authors: Oscar Rubiocabezas, Palle Serup, Jan N. Jensen, Ethel Codner, Maria I Hodgson, Sian Ellard, Andrew T. HattersleyAbstract:OBJECTIVE NEUROG3 plays a central role in the development of both pancreatic islets and enteroendocrine cells. Homozygous hypomorphic missense mutations in NEUROG3 have been recently associated with a rare form of congenital malabsorptive diarrhea secondary to enteroendocrine cell dysgenesis. Interestingly, the patients did not develop neonatal diabetes but childhood-onset diabetes. We hypothesized that null mutations in NEUROG3 might be responsible for the disease in a patient with permanent neonatal diabetes and severe congenital malabsorptive diarrhea. RESEARCH DESIGN AND METHODS The single coding exon of NEUROG3 was amplified and sequenced from genomic DNA. The mutant protein isoforms were functionally characterized by measuring their ability to bind to an E-box element in the NEUROD1 promoter in vitro and to induce ectopic endocrine cell formation and cell delamination after in ovo chicken endoderm electroporation. RESULTS Two different heterozygous point mutations in NEUROG3 were identified in the proband [c.82G>T (p.E28X) and c.404T>C (p.L135P)], each being inherited from an unaffected parent. Both in vitro and in vivo functional studies indicated that the mutant isoforms are biologically inactive. In keeping with this, no enteroendocrine cells were detected in intestinal biopsy samples from the patient. CONCLUSIONS Severe deficiency of neurogenin 3 causes a rare novel subtype of permanent neonatal diabetes. This finding confirms the essential role of NEUROG3 in islet development and function in humans.
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the transcriptional activity of NEUROG3 affects migration and differentiation of ectopic endocrine cells in chicken endoderm
Developmental Dynamics, 2010Co-Authors: Louise Rosenberg, Palle Serup, Jan N. Jensen, Merete L Lafon, Jesper Pedersen, Hani Yassin, Jacob HeckshersorensenAbstract:NEUROG3 is expressed transiently in pancreatic endocrine progenitors where it is responsible for activating a transcription factor cascade which eventually defines the mature endocrine cells. However, the mechanism by which NEUROG3 regulates different aspects of the endocrine differentiation program is less clear. In this report we used in ovo electroporation to investigate how manipulation of NEUROG3 protein activity affected migration, differentiation and fate determination. We found that changes in the onset of NEUROG3 expression only had minor effect on differentiation. However increasing the transcriptional activity of NEUROG3 by fusing it to VP16 or co-electroporating with Ep300 caused the electroporated cells to migrate rather than differentiate. In contrast, reducing the transcriptional activity of NEUROG3 by deleting parts of the activation domain, by fusing NEUROG3 to the engrailed repressor domain, or co-electroporating with Hdac1 greatly increased the proportion of glucagon expressing cells. Developmental Dynamics 239:1950-1966, 2010. (C) 2010 Wiley-Liss, Inc. (Less)
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the transcriptional activity of NEUROG3 affects migration and differentiation of ectopic endocrine cells in chicken endoderm
Developmental Dynamics, 2010Co-Authors: Louise Rosenberg, Palle Serup, Jan N. Jensen, Merete L Lafon, Jesper Pedersen, Hani Yassin, Jacob HeckshersorensenAbstract:NEUROG3 is expressed transiently in pancreatic endocrine progenitors where it is responsible for activating a transcription factor cascade which eventually defines the mature endocrine cells. However, the mechanism by which NEUROG3 regulates different aspects of the endocrine differentiation program is less clear. In this report we used in ovo electroporation to investigate how manipulation of NEUROG3 protein activity affected migration, differentiation and fate determination. We found that changes in the onset of NEUROG3 expression only had minor effect on differentiation. However increasing the transcriptional activity of NEUROG3 by fusing it to VP16 or co-electroporating with Ep300 caused the electroporated cells to migrate rather than differentiate. In contrast, reducing the transcriptional activity of NEUROG3 by deleting parts of the activation domain, by fusing NEUROG3 to the engrailed repressor domain, or co-electroporating with Hdac1 greatly increased the proportion of glucagon expressing cells.
Mark A Magnuson - One of the best experts on this subject based on the ideXlab platform.
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rock nmmyoii notch and NEUROG3 gene dosage link epithelial morphogenesis with cell fate in the pancreatic endocrine progenitor niche
Development, 2018Co-Authors: Eric D Bankaitis, Matthew E Bechard, Mark A Magnuson, Christopher V.e. WrightAbstract:ABSTRACT During mouse pancreas organogenesis, endocrine cells are born from progenitors residing in an epithelial plexus niche. After a period in a lineage-primed NEUROG3LO state, progenitors become endocrine committed via upregulation of NEUROG3. We find that the NEUROG3LO to NEUROG3HI transition is associated with distinct stages of an epithelial egression process: narrowing the apical surface of the cell, basalward cell movement and eventual cell-rear detachment from the apical lumen surface to allow clustering as nascent islets under the basement membrane. Apical narrowing, basalward movement and NEUROG3 transcriptional upregulation still occur without NEUROG3 protein, suggesting that morphogenetic cues deployed within the plexus initiate endocrine commitment upstream or independently of NEUROG3. NEUROG3 is required for cell-rear detachment and complete endocrine-cell birth. The ROCK-nmMyoII pathway coordinates epithelial-cell morphogenesis and the progression through NEUROG3-expressing states. NmMyoII is necessary for apical narrowing, basalward cell displacement and NEUROG3 upregulation, but all three are limited by ROCK activity. We propose that ROCK-nmMyoII activity, NEUROG3 gene-dose and Notch signaling integrate endocrine fate allocation with epithelial plexus growth and morphogenesis, representing a feedback control circuit that coordinates morphogenesis with lineage diversification in the endocrine-birth niche.
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fucci tracking shows cell cycle dependent NEUROG3 variation in pancreatic progenitors
Genesis, 2017Co-Authors: Matthew E Bechard, Eric D Bankaitis, Alessandro Ustione, David W Piston, Mark A Magnuson, Christopher V.e. WrightAbstract:During pancreas organogenesis, NEUROG3HI endocrine-committing cells are generated from a population of Sox9+ mitotic progenitors with only a low level of NEUROG3 transcriptional activity (NEUROG3TA.LO ). Low-level NEUROG3 protein, in NEUROG3TA.LO cells, is required to maintain their mitotic endocrine-lineage-primed status. Herein, we describe a NEUROG3-driven FUCCI cell-cycle reporter (NEUROG3P2A.FUCCI ) derived from a NEUROG3 BAC transgenic reporter that functions as a loxed cassette acceptor (LCA). In cycling Sox9+ NEUROG3TA.LO progenitors, the majority of cells in S-G2 -M phases have undetectable levels of NEUROG3 with increased expression of endocrine progenitor markers, while those in G1 have low NEUROG3 levels with increased expression of endocrine differentiation markers. These findings support a model in which variations in NEUROG3 protein levels are coordinated with cell-cycle phase progression in NEUROG3TA.LO progenitors with entrance into G1 triggering a concerted effort, beyond increasing NEUROG3 levels, to maintain an endocrine-lineage-primed state by initiating expression of the downstream endocrine differentiation program prior to endocrine-commitment.
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fucci tracking shows that NEUROG3 levels vary with cell cycle phase in endocrine biased pancreatic progenitors
bioRxiv, 2017Co-Authors: Matthew E Bechard, Eric D Bankaitis, Alessandro Ustione, David W Piston, Mark A Magnuson, Christopher V.e. WrightAbstract:NEUROG3 HI endocrine-committing cells are generated from a population of Sox9 + mitotic progenitors with only a low level of NEUROG3 transcriptional activity ( NEUROG3 TA.LO ). Low-level NEUROG3 protein, in NEUROG3 TA.LO cells, is required to maintain their mitotic endocrine-lineage-primed status. Herein, we describe a NEUROG3 -driven FUCCI cell-cycle reporter ( NEUROG3 P2A.FUCCI ) derived from a NEUROG3 BAC transgenic reporter that functions as a loxed cassette acceptor (LCA). In cycling Sox9 + NEUROG3 TA.LO progenitors, the majority of cells in S-G 2 -M phases have undetectable levels of NEUROG3 with increased expression of endocrine progenitor markers, while those in G 1 have low NEUROG3 levels with increased expression of endocrine differentiation markers. These findings support a model in which variations in NEUROG3 protein levels are coordinated with cell-cycle phase progression in NEUROG3 TA.LO progenitors with entrance into G 1 triggering a concerted effort, beyond increasing NEUROG3 levels, to maintain an endocrine-lineage-primed state by initiating expression of the downstream endocrine differentiation program prior to endocrine-commitment.
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precommitment low level NEUROG3 expression defines a long lived mitotic endocrine biased progenitor pool that drives production of endocrine committed cells
Genes & Development, 2016Co-Authors: Matthew E Bechard, Eric D Bankaitis, Alessandro Ustione, David W Piston, Mark A Magnuson, Susan B Hipkens, Yuping Yang, Christopher V.e. WrightAbstract:The current model for endocrine cell specification in the pancreas invokes high-level production of the transcription factor Neurogenin 3 (NEUROG3) in Sox9(+) bipotent epithelial cells as the trigger for endocrine commitment, cell cycle exit, and rapid delamination toward proto-islet clusters. This model posits a transient NEUROG3 expression state and short epithelial residence period. We show, however, that a NEUROG3(TA.LO) cell population, defined as NEUROG3 transcriptionally active and Sox9(+) and often containing nonimmunodetectable NEUROG3 protein, has a relatively high mitotic index and prolonged epithelial residency. We propose that this endocrine-biased mitotic progenitor state is functionally separated from a pro-ductal pool and endows them with long-term capacity to make endocrine fate-directed progeny. A novel BAC transgenic NEUROG3 reporter detected two types of mitotic behavior in Sox9(+) NEUROG3(TA.LO) progenitors, associated with progenitor pool maintenance or derivation of endocrine-committed NEUROG3(HI) cells, respectively. Moreover, limiting NEUROG3 expression dramatically increased the proportional representation of Sox9(+) NEUROG3(TA.LO) progenitors, with a doubling of its mitotic index relative to normal NEUROG3 expression, suggesting that low NEUROG3 expression is a defining feature of this cycling endocrine-biased state. We propose that Sox9(+) NEUROG3(TA.LO) endocrine-biased progenitors feed production of NEUROG3(HI) endocrine-committed cells during pancreas organogenesis.
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insm1 promotes endocrine cell differentiation by modulating the expression of a network of genes that includes NEUROG3 and ripply3
Development, 2014Co-Authors: Anna B Osipovich, Susan B Hipkens, Qiaoming Long, Elisabetta Manduchi, Rama Gangula, Judsen Schneider, Tadashi Okubo, Christian J Stoeckert, Shinji Takada, Mark A MagnusonAbstract:Insulinoma associated 1 (Insm1) plays an important role in regulating the development of cells in the central and peripheral nervous systems, olfactory epithelium and endocrine pancreas. To better define the role of Insm1 in pancreatic endocrine cell development we generated mice with an Insm1GFPCre reporter allele and used them to study Insm1-expressing and null populations. Endocrine progenitor cells lacking Insm1 were less differentiated and exhibited broad defects in hormone production, cell proliferation and cell migration. Embryos lacking Insm1 contained greater amounts of a non-coding NEUROG3 mRNA splice variant and had fewer NEUROG3/Insm1 co-expressing progenitor cells, suggesting that Insm1 positively regulates NEUROG3. Moreover, endocrine progenitor cells that express either high or low levels of Pdx1, and thus may be biased towards the formation of specific cell lineages, exhibited cell type-specific differences in the genes regulated by Insm1. Analysis of the function of Ripply3, an Insm1-regulated gene enriched in the Pdx1-high cell population, revealed that it negatively regulates the proliferation of early endocrine cells. Taken together, these findings indicate that in developing pancreatic endocrine cells Insm1 promotes the transition from a ductal progenitor to a committed endocrine cell by repressing a progenitor cell program and activating genes essential for RNA splicing, cell migration, controlled cellular proliferation, vasculogenesis, extracellular matrix and hormone secretion.
Francis C. Lynn - One of the best experts on this subject based on the ideXlab platform.
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Single-Cell Transcriptome Profiling of Mouse and hESC-Derived Pancreatic Progenitors
'Elsevier BV', 2018Co-Authors: Nicole A.j. Krentz, Michelle Y.y. Lee, Shannon L.j. Sproul, Alexandra Maslova, Shugo Sasaki, Francis C. LynnAbstract:Summary: Human embryonic stem cells (hESCs) are a potential unlimited source of insulin-producing β cells for diabetes treatment. A greater understanding of how β cells form during embryonic development will improve current hESC differentiation protocols. All pancreatic endocrine cells, including β cells, are derived from NEUROG3-expressing endocrine progenitors. This study characterizes the single-cell transcriptomes of 6,905 mouse embryonic day (E) 15.5 and 6,626 E18.5 pancreatic cells isolated from NEUROG3-Cre; Rosa26mT/mG embryos, allowing for enrichment of endocrine progenitors (yellow; tdTomato + EGFP) and endocrine cells (green; EGFP). Using a NEUROG3-2A-eGFP CyT49 hESC reporter line (N5-5), 4,462 hESC-derived GFP+ cells were sequenced. Differential expression analysis revealed enrichment of markers that are consistent with progenitor, endocrine, or previously undescribed cell-state populations. This study characterizes the single-cell transcriptomes of mouse and hESC-derived endocrine progenitors and serves as a resource (https://lynnlab.shinyapps.io/embryonic_pancreas) for improving the formation of functional β-like cells from hESCs. : In this article, Krentz and colleagues characterize the single-cell transcriptome of E15.5 and E18.5 mouse pancreatic cells and hESC-derived endocrine cells. They identify pancreatic cell-type-specific genes in the mouse and compare hESC-derived endocrine cells to fetal mouse endocrine cells and human islets. Keywords: pancreas development, scRNA-seq, endocrine progenitors, NEUROG3, hESCs, mT/mG, CyT49, diabetes, cell therap
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Phosphorylation of NEUROG3 Links Endocrine Differentiation to the Cell Cycle in Pancreatic Progenitors
Developmental cell, 2017Co-Authors: Nicole A.j. Krentz, Michael S. German, Dennis Van Hoof, Akie Watanabe, Mei Tang, Cuilan Nian, Francis C. LynnAbstract:During pancreatic development, proliferating pancreatic progenitors activate the proendocrine transcription factor neurogenin 3 (NEUROG3), exit the cell cycle, and differentiate into islet cells. The mechanisms that direct robust NEUROG3 expression within a subset of progenitor cells control the size of the endocrine population. Here we demonstrate that NEUROG3 is phosphorylated within the nucleus on serine 183, which catalyzes its hyperphosphorylation and proteosomal degradation. During progression through the progenitor cell cycle, NEUROG3 phosphorylation is driven by the actions of cyclin-dependent kinases 2 and 4/6 at G1/S cell-cycle checkpoint. Using models of mouse and human pancreas development, we show that lengthening of the G1 phase of the pancreatic progenitor cell cycle is essential for proper induction of NEUROG3 and initiation of endocrine cell differentiation. In sum, these studies demonstrate that progenitor cell-cycle G1 lengthening, through its actions on stabilization of NEUROG3, is an essential variable in normal endocrine cell genesis.
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induction of pancreatic islet cell differentiation by the neurogenin neurod cascade
Differentiation, 2008Co-Authors: Rosa Gasa, Francis C. Lynn, Caroline Mrejen, Peter Skewescox, Lidia Martinez Sanchez, Katherine Yang, Chin Hsing Lin, Ramon Gomis, Michael S. GermanAbstract:The related basic helix-loop-helix transcription factors neurogenin3 (NEUROG3) and neurogenic differentiation 1 (NeuroD1) regulate pancreatic islet cell formation. The transient expression of NEUROG3 initiates endocrine differentiation and activates its target, NeuroD1, which continues the endocrine differentiation process. Despite their distinct developmental roles, the expression of either factor can drive islet differentiation in progenitor cells. To determine whether NEUROG3 and NeuroD1 function by targeting a common set of genes, we compared gene expression patterns in cells ectopically expressing these two factors using cDNA microarrays. The array data demonstrated that both factors regulated largely overlapping sets of genes, providing the molecular basis for their functional equivalence in gain-of-functions approaches. Distinct differences in the timing and level of expression of a subset of target genes, however, show that the functions of these two factors are not completely redundant. Interestingly, in addition to NeuroD1, NEUROG3 also induced both NeuroD2 and NeuroD4 gene expression. NeuroD2 mRNA peaked in the embryonic pancreas during endocrine differentiation and induced endocrine differentiation in vitro. These data suggest possible redundant roles for the NeuroD1 paralogs NeuroD2 and NeuroD4 in pancreatic endocrine differentiation and their potential utility in cell-based therapies for diabetes mellitus.
Michael S. German - One of the best experts on this subject based on the ideXlab platform.
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null mutations of NEUROG3 are associated with delayed onset diabetes mellitus
JCI insight, 2020Co-Authors: Sergio R Solorzanovargas, Matthew Bjerknes, Hazel Cheng, Jiafang Wang, Michael S. German, Manuel Garciacareaga, Pisit Pitukcheewanont, Senta Georgia, Martin G MartinAbstract:Biallelic mutations of the gene encoding the transcription factor NEUROG3 are associated with a rare disorder that presents in neonates as generalized malabsorption - due to a complete absence of enteroendocrine cells - followed, in early childhood or beyond, by insulin-dependent diabetes mellitus (IDDM). The commonly delayed onset of IDDM suggests a differential requirement for NEUROG3 in endocrine cell generation in the human pancreas versus the intestine. However, previously identified human mutations were hypomorphic and, hence, may have had residual function in pancreas. We report 2 patients with biallelic functionally null variants of the NEUROG3 gene who nonetheless did not present with IDDM during infancy but instead developed permanent IDDM during middle childhood ages. The variants showed no evidence of function in traditional promoter-based assays of NEUROG3 function and also failed to exhibit function in a variety of potentially novel in vitro and in vivo molecular assays designed to discern residual NEUROG3 function. These findings imply that, unlike in mice, pancreatic endocrine cell generation in humans is not entirely dependent on NEUROG3 expression and, hence, suggest the presence of unidentified redundant in vivo pathways in human pancreas capable of yielding β cell mass sufficient to maintain euglycemia until early childhood.
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Phosphorylation of NEUROG3 Links Endocrine Differentiation to the Cell Cycle in Pancreatic Progenitors
Developmental cell, 2017Co-Authors: Nicole A.j. Krentz, Michael S. German, Dennis Van Hoof, Akie Watanabe, Mei Tang, Cuilan Nian, Francis C. LynnAbstract:During pancreatic development, proliferating pancreatic progenitors activate the proendocrine transcription factor neurogenin 3 (NEUROG3), exit the cell cycle, and differentiate into islet cells. The mechanisms that direct robust NEUROG3 expression within a subset of progenitor cells control the size of the endocrine population. Here we demonstrate that NEUROG3 is phosphorylated within the nucleus on serine 183, which catalyzes its hyperphosphorylation and proteosomal degradation. During progression through the progenitor cell cycle, NEUROG3 phosphorylation is driven by the actions of cyclin-dependent kinases 2 and 4/6 at G1/S cell-cycle checkpoint. Using models of mouse and human pancreas development, we show that lengthening of the G1 phase of the pancreatic progenitor cell cycle is essential for proper induction of NEUROG3 and initiation of endocrine cell differentiation. In sum, these studies demonstrate that progenitor cell-cycle G1 lengthening, through its actions on stabilization of NEUROG3, is an essential variable in normal endocrine cell genesis.
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induction of pancreatic islet cell differentiation by the neurogenin neurod cascade
Differentiation, 2008Co-Authors: Rosa Gasa, Francis C. Lynn, Caroline Mrejen, Peter Skewescox, Lidia Martinez Sanchez, Katherine Yang, Chin Hsing Lin, Ramon Gomis, Michael S. GermanAbstract:The related basic helix-loop-helix transcription factors neurogenin3 (NEUROG3) and neurogenic differentiation 1 (NeuroD1) regulate pancreatic islet cell formation. The transient expression of NEUROG3 initiates endocrine differentiation and activates its target, NeuroD1, which continues the endocrine differentiation process. Despite their distinct developmental roles, the expression of either factor can drive islet differentiation in progenitor cells. To determine whether NEUROG3 and NeuroD1 function by targeting a common set of genes, we compared gene expression patterns in cells ectopically expressing these two factors using cDNA microarrays. The array data demonstrated that both factors regulated largely overlapping sets of genes, providing the molecular basis for their functional equivalence in gain-of-functions approaches. Distinct differences in the timing and level of expression of a subset of target genes, however, show that the functions of these two factors are not completely redundant. Interestingly, in addition to NeuroD1, NEUROG3 also induced both NeuroD2 and NeuroD4 gene expression. NeuroD2 mRNA peaked in the embryonic pancreas during endocrine differentiation and induced endocrine differentiation in vitro. These data suggest possible redundant roles for the NeuroD1 paralogs NeuroD2 and NeuroD4 in pancreatic endocrine differentiation and their potential utility in cell-based therapies for diabetes mellitus.
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p38 mapk is involved in activin a and hepatocyte growth factor mediated expression of pro endocrine gene neurogenin 3 in ar42j b13 cells
Journal of Biological Chemistry, 2003Co-Authors: Takeshi Ogihara, Michael S. German, Hirotaka Watada, Rei Kanno, Fuki Ikeda, Takashi Nomiyama, Yasushi Tanaka, Atsuhito Nakao, Itaru Kojima, Ryuzo KawamoriAbstract:Neurogenin3 (ngn3) is a transcription factor that is essential for the differentiation of pancreatic endocrine cells. To investigate the signaling pathway that regulates ngn3 expression, we used AR42J-B13 cells as a model of the differentiation of pancreatic islets. In these cells, treatment with activin A and hepatocyte growth factor (HGF) induced the expression of ngn3. Reporter gene analysis using human ngn3 gene (NEUROG3) promoter fragments of various lengths identified the region between -402 and -327 bp of NEUROG3 as an activin A- and HGF-responsive DNA sequence. This DNA sequence normally functions as a repressor in AR42J-B13 cells, but treatment with activin A and HGF negates the repressor activity. Interestingly, function of the activin A- and HGF-responsive sequence was not influenced by the overexpression of the Smad inhibitory factor, Smad7. Instead, activin A and HGF activation was inhibited by overexpression of a dominant-negative mutant of transforming growth factor-beta-activated kinase 1 (TAK1), or mitogen-activated protein kinase kinase 3 (MKK3), or by treatment with a p38 MAPK-specific inhibitor, SB203580. Activin A and HGF function through the TAK1-MKK3-p38 MAPK pathway to relieve transcription repressors located between -402 and -326 bp on the NEUROG3 promoter, and consequently activate ngn3 expression and endocrine differentiation of AR42J-B13 cells.
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Mutations in the coding region of the neurogenin 3 gene (NEUROG3) are not a common cause of maturity-onset diabetes of the young in Japanese subjects.
Diabetes, 2001Co-Authors: Laura Del Bosque-plata, Joseph Lin, Yukio Horikawa, Peter E.h. Schwarz, Nancy J. Cox, Naoko Iwasaki, Makiko Ogata, Yasuhiko Iwamoto, Michael S. German, Graeme I. BellAbstract:Mutations in transcription factors that play a role in the development of the endocrine pancreas, such as insulin promoter factor-1 and NeuroD1/BETA2, have been associated with diabetes. Cell type–specific members of the basic helix-loop-helix (bHLH) family of transcription factors play essential roles in the development and maintenance of many differentiated cell types, including pancreatic β-cells. Neurogenin 3 is a bHLH transcription factor that is expressed in the developing central nervous system and the embryonic pancreas. Mice lacking this transcription factor fail to develop any islet endocrine cells and die postnatally from diabetes. Because neurogenin 3 is required for the development of β-cells and other pancreatic islet cell types, we considered it a candidate diabetes gene. We screened the coding region of the human neurogenin 3 gene ( NEUROG3 ) for mutations in a group of unrelated Japanese subjects with maturity-onset diabetes of the young (MODY). We found three sequence variants: a deletion of 2-bp in the 5′-untranslated region ( NEUROG3 -g.-44–45delCA), a G-to-A substitution in codon 167 (g.499G/A), resulting in a Gly-to-Arg replacement (G/R167), and a T-to-C substitution in codon 199 (g.596T/C), resulting in a Phe/Ser polymorphism F/S199. These polymorphisms were not associated with MODY, thereby suggesting that mutations in NEUROG3 are not a common cause of MODY in Japanese patients.