Mus musculus
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PROVIDER: PRJNA174098 | ENA |
REPOSITORIES: ENA
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Project description:Nkx6.1 target genes were identified in mature pancreatic islets by comparing gene expression in conditional Nkx6.1-ablated islets versus control islets using microarray analysis.
2013-09-12 | GSE40470 | GEO
Project description:Nkx6.1 target genes were identified in mature pancreatic islets by comparing gene expression in conditional Nkx6.1-ablated islets versus control islets using microarray analysis. Nkx6.1 was conditionally ablated in mature pancreatic islets by recombination of a Nkx6.1-flox allele using the tamoxifen-inducible Pdx1-CreERTM allele (Gu et al 2002). Mice were injected with 2 mg/25 g tamoxifen in corn oil four times between 4 and 6 weeks of age. Islets were isolated after the final tamoxifen injection. Total RNA was isolated and pooled from pancreata of 6 week old Nkx6.1fl/-;Pdx1-CreERTM (mutant) versus Nkx6.1fl/+;Pdx1-CreERTM (control) littermates for 3 biological replicates.
2013-09-12 | E-GEOD-40470 | biostudies-arrayexpress
Project description:The homeodomain transcription factor Nkx6.1 plays an important role in pancreatic islet β-cell development, but its effects on adult β-cell function, survival, and proliferation are not well understood. In the present study, we demonstrated that treatment of primary rat pancreatic islets with a cytomegalovirus promoter-driven recombinant adenovirus containing the Nkx6.1 cDNA (AdCMV-Nkx6.1) causes dramatic increases in [methyl-3H] thymidine and 5-bromo-2'-deoxyuridine (BrdU) incorporation and in the number of cells per islet relative to islets treated with a control adenovirus (AdCMV-βGAL), whereas suppression of Nkx6.1 expression reduces thymidine incorporation. Immunocytochemical studies reveal that >80% of BrdU-positive cells in AdCMV-Nkx6.1-treated islets are β cells. Microarray, real-time PCR, and immunoblot analyses reveal that overexpression of Nkx6.1 in rat islets causes concerted upregulation of a cadre of cell cycle control genes, including those encoding cyclins A, B, and E, and several regulatory kinases. Cyclin E is upregulated earlier than the other cyclins, and adenovirus-mediated overexpression of cyclin E is shown to be sufficient to activate islet cell proliferation. Moreover, chromatin immunoprecipitation assays demonstrate direct interaction of Nkx6.1 with the cyclin A2 and B1 genes. Overexpression of Nkx6.1 in rat islets caused a clear enhancement of glucose-stimulated insulin secretion (GSIS), whereas overexpression of Nkx6.1 in human islets caused an increase in the level of [3H]thymidine incorporation that was twice the control level, along with complete retention of GSIS. We conclude that Nkx6.1 is among the very rare factors capable of stimulating β-cell replication with retention or enhancement of function, properties that may be exploitable for expansion of β-cell mass in treatment of both major forms of diabetes. Keywords: Insulin secretion, islet biology, transcription factor, cell cycle regulation, diabetes We utilized a âsample x referenceâ experimental design strategy in which RNA extracted from rat pancreatic islets was hybridized to the microarray slide in the presence of labeled rat reference RNA (RRR, Stratagene, LaJolla, CA). Cultures were treated with adenoviruses expressing either the hamster form of Nkx6.1 or the beta-galactosidase enzyme. 5 biological replicates each representing independent islet isolations were used for microarray analysis. Briefly, five hundred nanograms of total RNA were used for gene expression profiling following reverse transcription and T-7 polymerase-mediated amplification/labeling with Cyanine-5. Labeled subject cRNA was co-hybridized to Operon rat 27K oligonucleotide arrays with equimolar amounts of Cyanine-3 labeled RRR. Slides were hybridized, washed, and scanned on a Gene Pix 5000 microarray scanner.
2010-05-18 | E-GEOD-13153 | biostudies-arrayexpress
Project description:The homeodomain transcription factor Nkx6.1 plays an important role in pancreatic islet β-cell development, but its effects on adult β-cell function, survival, and proliferation are not well understood. In the present study, we demonstrated that treatment of primary rat pancreatic islets with a cytomegalovirus promoter-driven recombinant adenovirus containing the Nkx6.1 cDNA (AdCMV-Nkx6.1) causes dramatic increases in [methyl-3H] thymidine and 5-bromo-2'-deoxyuridine (BrdU) incorporation and in the number of cells per islet relative to islets treated with a control adenovirus (AdCMV-βGAL), whereas suppression of Nkx6.1 expression reduces thymidine incorporation. Immunocytochemical studies reveal that >80% of BrdU-positive cells in AdCMV-Nkx6.1-treated islets are β cells. Microarray, real-time PCR, and immunoblot analyses reveal that overexpression of Nkx6.1 in rat islets causes concerted upregulation of a cadre of cell cycle control genes, including those encoding cyclins A, B, and E, and several regulatory kinases. Cyclin E is upregulated earlier than the other cyclins, and adenovirus-mediated overexpression of cyclin E is shown to be sufficient to activate islet cell proliferation. Moreover, chromatin immunoprecipitation assays demonstrate direct interaction of Nkx6.1 with the cyclin A2 and B1 genes. Overexpression of Nkx6.1 in rat islets caused a clear enhancement of glucose-stimulated insulin secretion (GSIS), whereas overexpression of Nkx6.1 in human islets caused an increase in the level of [3H]thymidine incorporation that was twice the control level, along with complete retention of GSIS. We conclude that Nkx6.1 is among the very rare factors capable of stimulating β-cell replication with retention or enhancement of function, properties that may be exploitable for expansion of β-cell mass in treatment of both major forms of diabetes. Keywords: Insulin secretion, islet biology, transcription factor, cell cycle regulation, diabetes
2008-10-11 | GSE13153 | GEO
Project description:Although early developmental processes involve cell fate decisions that define the body axes and establish progenitor cell pools, development does not cease once cells are specified. Instead, most cells undergo specific maturation events where changes in the cell transcriptome ensure that the proper gene products are expressed to carry out unique physiological functions. Pancreatic acinar cells mature post-natally to handle an extensive protein synthetic load, establsih organized apical-basal polarity for zymogen granule trafficking, and assemble gap-junctions to perimt efficient cell-cell communication. Despite significant progress in defining transcriptional networks that control initial acinar cell specification and differentiation decisions, little is know regarding the role of transcription factors in the specification and maintenance of maturation events. One candidate maturation effector is MIST1, a secretory cell-restricted transcription factor that has been implicated in controlling regulated exocytosis events in a number of cell types. Embryonic knock-out of MIST1 generates acinar cells that fail to establish an apical-basal organization, fail to properly localize zymogen granule and fail to communicate intra-cellularly, making the exocrine organ highly suceptible to pancreatic diseases. In an effort to identify the gene expression differences responsible for MIST1 regulating mature acinar properties. We generated a tamoxifen-inducible mouse model where MIST1 expression could be activated in vivoand performed gene expression arrays on wildtype, MIST1-null, and induced MIST1 pancreatic RNA.
2012-05-04 | GSE34232 | GEO
Project description:The homeodomain transcription factor, Pdx-1, has important roles in pancreatic development and M-NM-2-cell function and survival. In the present study, we demonstrate that adenovirus-mediated overexpression of Pdx-1 in rat or human islets also stimulates cell replication. Moreover, co-overexpression of Pdx-1 with another homeodomain transcription factor, Nkx6.1, has an additive effect on proliferation compared to either factor alone, implying discrete activating mechanisms. Consistent with this, Nkx6.1 stimulates mainly M-NM-2-cell proliferation, whereas Pdx-1 stimulates both M-NM-1- and M-NM-2-cell proliferation. Furthermore, cyclins D1/D2 are upregulated by Pdx-1 but not by Nkx6.1, and inhibition of cdk4 blocks Pdx-1- but not Nkx6.1-stimulated islet cell proliferation. Genes regulated by Pdx-1 and not Nkx6.1 were identified by microarray analysis. Two members of the transient receptor potential cation (TRPC) channel family, TRPC3 and TRPC6, are upregulated by Pdx-1 overexpression, and siRNA-mediated knockdown of TRPC3/6 or TRPC6 alone inhibits Pdx-1-induced but not Nkx6.1-induced islet cell proliferation. Pdx-1 also stimulates ERK1/2 phosphorylation, an effect partially blocked by knockdown of TRPC3/6, and blockade of ERK1/2 activation with a MEK1/2 inhibitor partially impairs Pdx-1-stimulated proliferation. These studies define a pathway by which overexpression of Pdx-1 activates islet cell proliferation that is distinct from and additive to a pathway activated by Nkx6.1. We identified genes that were upregulated or downregulated at 48 h with Pdx-1 overexpression as compared to untreated and M-NM-2gal controls. We set up a microarray using primary rat islets that were left untreated or transduced with adenoviruses overexpressing M-NM-2gal or Pdx-1 for 48 h.
2013-09-01 | E-GEOD-49786 | biostudies-arrayexpress
Project description:Loss of functional beta-cell mass is a hallmark of Type 1 and Type 2 diabetes, and methods for restoring these cells are needed. We have previously reported that overexpression of the homeodomain transcription factor Nkx6.1 in rat pancreatic islets induces beta-cell proliferation and enhances glucose-stimulated insulin secretion, but the pathway by which Nkx6.1 activates beta-cell expansion has not been defined. Here we demonstrate that Nkx6.1 induces expression of the Nr4a1 and Nr4a3 orphan nuclear receptors, and that these factors are both necessary and sufficient for Nkx6.1-mediated beta-cell proliferation. Consistent with this finding, global knockout of Nr4a1 results in a decrease in beta-cell area in neonatal and young mice. Overexpression of Nkx6.1 and the Nr4a receptors results in increased expression of key cell cycle inducers E2F1 and cyclin E1. Furthermore, Nkx6.1 and Nr4a receptors induce components of the anaphase-promoting complex, including Ube2c, resulting in degradation of the cell cycle inhibitor p21CIP1. These studies identify a new bipartite pathway for activation of beta-cell proliferation, suggesting several new targets for expansion of functional beta-cell mass. We set up a microarray using primary rat islets that were left untreated or transduced with adenoviruses overexpressing betagal or Nkx6.1 for 48 h.
2014-02-18 | E-GEOD-55077 | biostudies-arrayexpress
Project description:Although early developmental processes involve cell fate decisions that define the body axes and establish progenitor cell pools, development does not cease once cells are specified. Instead, most cells undergo specific maturation events where changes in the cell transcriptome ensure that the proper gene products are expressed to carry out unique physiological functions. Pancreatic acinar cells mature post-natally to handle an extensive protein synthetic load, establsih organized apical-basal polarity for zymogen granule trafficking, and assemble gap-junctions to perimt efficient cell-cell communication. Despite significant progress in defining transcriptional networks that control initial acinar cell specification and differentiation decisions, little is know regarding the role of transcription factors in the specification and maintenance of maturation events. One candidate maturation effector is MIST1, a secretory cell-restricted transcription factor that has been implicated in controlling regulated exocytosis events in a number of cell types. Embryonic knock-out of MIST1 generates acinar cells that fail to establish an apical-basal organization, fail to properly localize zymogen granule and fail to communicate intra-cellularly, making the exocrine organ highly suceptible to pancreatic diseases. In an effort to identify the gene expression differences responsible for MIST1 regulating mature acinar properties. We generated a tamoxifen-inducible mouse model where MIST1 expression could be activated in vivoand performed gene expression arrays on wildtype, MIST1-null, and induced MIST1 pancreatic RNA. RNA was isolated from pancreata of 8 week old mice using the Qiagen RNeasy Midi kit. Pancreta of wildtype, MIST1-null, and MIST1-null with a tamoxifen inducible MIST1-expressing transgene were harvested 36 hours post-tamoxifen administration. Therefore, this experiment provides information on steady-state gene expression differences between wildtype and MIST1-null mice as well as immediate gene expression changes induced by MIST1 expression.
2012-05-03 | E-GEOD-34232 | biostudies-arrayexpress