Signal Transducer and Activator of Transcription 5 Activation Is Sufficient to Drive Transcriptional Induction of Cyclin D2 Gene and Proliferation of Rat Pancreatic β-Cells

Friedrichsen, Birgitte Nissen; Richter, Henrijette E.; Hansen, Jens Aage; Rhodes, Christopher J.; Nielsen, Jens Høiriis; Billestrup, Nils; Møldrup, Annette

doi:10.1210/me.2002-0356

Cited by 90 publications

(82 citation statements)

References 65 publications

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“…Furthermore, we have recently shown that this up-regulation is mediated by a direct action of STAT5 on the cyclin D2 promoter (Friedrichsen et al 2003). In the present study, we have investigated the effect of GLP-1 on cyclin D mRNA and protein expression in INS-1E cells, and found that this treatment is associated with a specific elevation of cyclin D1 in a time-dependent manner with maximal induction at 6 and 12 h, respectively.…”

Section: Discussionmentioning

confidence: 67%

“…A firefly luciferase reporter construct containing 2·4 kb of the mouse cyclin D1 promoter (kindly provided by Dr Martin Eilers, University of Marburg, Marburg, Germany) along with the internal control plasmid TKrenilla (Promega) were transiently transfected into islet monolayer or INS-1E cells using LipofectAMINE 2000 (Invitrogen Life Technologies) as previously described (Friedrichsen et al 2003) using 2 µl Lipofect AMINE 2000/well. Islet and INS-1E cells were incubated overnight with DNA-lipofectamine-Optimem mix in RPMI 1640 containing 2% HS and Optimem, respectively.…”

Section: Transient Transfectionmentioning

confidence: 99%

“…The media were replaced for islet cells with RPMI 1640 containing 2% HS and for INS-1E cells with RPMI 1640 containing 0·25% BSA and 50 µM -mercaptoethanol, incubation continued for 24 h in the presence of compounds as indicated. Luciferase reporter assay was performed as previously described (Galsgaard et al 1999, Friedrichsen et al 2003.…”

Section: Transient Transfectionmentioning

confidence: 99%

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Stimulation of pancreatic β-cell replication by incretins involves transcriptional induction of cyclin D1 via multiple signalling pathways

Friedrichsen¹,

Neubauer²,

Lee³

et al. 2006

Journal of Endocrinology

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139

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The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), have been suggested to act as -cell growth factors and may therefore be of critical importance for the maintenance of a proper -cell mass. We have investigated the molecular mechanism of incretin-induced -cell replication in primary monolayer cultures of newborn rat islet cells. GLP-1, GIP and the long-acting GLP-1 derivative, liraglutide, increased -cell replication 50-80% at 10-100 nM upon a 24 h stimulus, whereas glucagon at a similar concentration had no significant effect. The stimulatory effect of GLP-1 and GIP was efficiently mimicked by the adenylate cyclase activator, forskolin, at 10 nM (90% increase) and was additive (170-250% increase) with the growth response to human growth hormone (hGH), indicating the use of distinct intracellular signalling pathways leading to mitosis by incretins and cytokines, respectively. The response to both GLP-1 and GIP was completely blocked by the protein kinase A (PKA) inhibitor, H89. In addition, the phosphoinositol 3-kinase (PI3K) inhibitor wortmannin and the mitogen-activated protein kinase kinase (MEK) inhibitor PD98059, both inhibited GLP-1-and GIP-stimulated proliferation. The p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, had no inhibitory effect on either GLP-1 or GIP stimulated proliferation. Cyclin Ds act as molecular switches for the G0/G1-S phase transition in many cell types and we have previously demonstrated hGH-induced cyclin D2 expression in the insulinoma cell line, INS-1. GLP-1 time-dependently induced the cyclin D1 mRNA and protein levels in INS-1E, whereas the cyclin D2 levels were unaffected. However, minor effect of GLP-1 stimulation was observed on the cyclin D3 mRNA levels. Transient transfection of a cyclin D1 promoter-luciferase reporter construct into islet monolayer cells or INS-1 cells revealed approximately a 2-3 fold increase of transcriptional activity in response to GLP-1 and GIP, and a 4-7 fold increase in response to forskolin. However, treatment of either cell type with hGH had no effect on cyclin D1 promoter activity. The stimulation of the cyclin D1 promoter by GLP-1 was inhibited by H89, wortmannin, and PD98059. We conclude that incretin-induced -cell replication is dependent on cAMP/PKA, p42 MAPK and PI3K activities, which may involve transcriptional induction of cyclin D1. GLP-1, GIP and liraglutide may have the potential to increase -cell replication in humans which would have significant impact on long-term diabetes treatment.

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Section: Discussionmentioning

confidence: 67%

Section: Transient Transfectionmentioning

confidence: 99%

Section: Transient Transfectionmentioning

confidence: 99%

See 1 more Smart Citation

Stimulation of pancreatic β-cell replication by incretins involves transcriptional induction of cyclin D1 via multiple signalling pathways

Friedrichsen¹,

Neubauer²,

Lee³

et al. 2006

Journal of Endocrinology

Self Cite

139

110

View full text Add to dashboard Cite

show abstract

“…After 48 h cells were exposed to either 150 pg/ml IL-1β for 1, 2, 4, 6, 8, 16 or 24 h or to varying amounts of IL-1β (18.75 pg/ml-2.4 ng/ml) for 6 h. RNA extraction was performed by the TRIzol method (GibcoBRL, Invitrogen, Carlsbad, CA, USA). For analysis of primary rat islet cells, monolayers were transduced with adenovirus encoding Luciferase or SOCS-3 at a concentration of 5×10 8 plaque forming units/ml [36]. The virus titre used was selected by transduction of islet cells with a green fluorescent protein (GFP)-encoding adenovirus and using a concentration giving >95% GFP-positive cells.…”

Section: Methodsmentioning

confidence: 99%

IL-1β-induced chemokine and Fas expression are inhibited by suppressor of cytokine signalling-3 in insulin-producing cells

et al. 2008

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Aims/hypothesis Chemokines recruit activated immune cells to sites of inflammation and are important mediators of insulitis. Activation of the pro-apoptotic receptor Fas leads to apoptosis-mediated death of the Fas-expressing cell. The pro-inflammatory cytokines IL-1β and IFN-γ regulate the transcription of genes encoding the Fas receptor and several chemokines. We have previously shown that suppressor of cytokine signalling (SOCS)-3 inhibits IL-1β-and IFN-γ-induced nitric oxide production in a beta cell line. The aim of this study was to investigate whether SOCS-3 can influence cytokine-induced Fas and chemokine expression in beta cells. Methods Using a beta cell line with inducible Socs3 expression or primary neonatal rat islet cells transduced with a Socs3-encoding adenovirus, we employed real-time RT-PCR analysis to investigate whether SOCS-3 affects cytokine-induced chemokine and Fas mRNA expression. The ability of SOCS-3 to influence the activity of cytokineresponsive Fas and Mcp-1 (also known as Ccl2) promoters was measured by reporter analysis. Results IL-1β induced a time-dependent increase in Mcp-1 and Mip-2 (also known as Cxcl2) mRNA expression after 6 h of stimulation in insulinoma (INS)-1 and neonatal rat islet cells. This induction was inhibited when Socs3 was expressed in the cells. In INS-1 cells, IL-1β + IFN-γ induced a tenfold and eightfold increase of Fas mRNA expression after 6 and 24 h, respectively. This induction was inhibited at both time-points when expression of Socs3 was induced. In promoter studies SOCS-3 significantly inhibited the cytokine-induced activity of Mcp-1 and Fas promoter constructs. Conclusions/interpretation SOCS-3 inhibits the expression of cytokine-induced chemokine and death-receptor Fas mRNA.Keywords Autoimmunity . Chemokine . Diabetes . IL-1 . Inflammation . NF-kappaB . Signalling . SOCS Abbreviations CIS cytokine-inducible SH2-containing protein FASL fas ligand GFP green fluorescent protein INS insulinoma MCP monocyte chemoattractant protein MIP-2 macrophage inflammatory protein-2 NFκB nuclear factor-κB SOCS suppressor of cytokine signalling STAT signal transducers and activators of transcription Diabetologia (2009) 52:281-288

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“…T cells from Stat5a/b-deficient mice fail to express cyclin D2 or cyclin D3 in response to anti-CD3 or IL-2 treatment (28). In the pancreatic ␤-cell line INS-1, a dominant negative form of Stat5 partially inhibited growth hormone-mediated expression of cyclin D2 (29), whereas a constitutively active version of Stat5 induced cyclin D2 expression (30). We have previously characterized a Stat5 binding element in the cyclin D2 promoter that is responsive to IL-2R signaling in T cells (31).…”

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confidence: 99%

A Permissive Role for Phosphatidylinositol 3-Kinase in the Stat5- mediated Expression of Cyclin D2 by the Interleukin-2 Receptor

Moon

Rubio

Martino

et al. 2004

Journal of Biological Chemistry

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The interleukin-2 (IL-2) receptor promotes T cell proliferation in part by inducing the expression of D-type cyclins, which enable cells to progress from the G 1 to S phase of the cell cycle. We previously showed that the IL-2 receptor induces expression of cyclin D2 by activating the transcription factor Stat5, which binds directly and immediately to a site upstream of the cyclin D2 promoter. We show here that subsequent transcription of the cyclin D2 gene occurs by a delayed, cycloheximide-sensitive mechanism, which implies the involvement of additional regulatory mechanisms. The transcription factor c-Myc is induced by Stat5 and is reported to bind to two E box motifs in the cyclin D2 promoter. However, in IL-2-stimulated T cells, c-Myc does not appear to be involved in cyclin D2 induction, since we found that these two E boxes are preferentially bound by USF-1 and USF-2 and, moreover, are dispensable for cyclin D2 promoter activity. Instead, we found that Stat5 activates the phosphatidylinositol 3-kinase (PI3 kinase) pathway by a delayed, cycloheximide-sensitive mechanism and that PI3 kinase activity is essential for the induction of cyclin D2 by Stat5. Chromatin immunoprecipitation experiments revealed that PI3 kinase is required for the optimal binding of RNA polymerase II to the promoters of cyclin D2 as well as other genes. Our results reveal a novel link between PI3 kinase and RNA polymerase II promoter binding activity and demonstrate discrete, coordinated roles for the PI3 kinase and Stat5 pathways in cyclin D2 transcription.

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Signal Transducer and Activator of Transcription 5 Activation Is Sufficient to Drive Transcriptional Induction of Cyclin D2 Gene and Proliferation of Rat Pancreatic β-Cells

Cited by 90 publications

References 65 publications

Stimulation of pancreatic β-cell replication by incretins involves transcriptional induction of cyclin D1 via multiple signalling pathways

Stimulation of pancreatic β-cell replication by incretins involves transcriptional induction of cyclin D1 via multiple signalling pathways

IL-1β-induced chemokine and Fas expression are inhibited by suppressor of cytokine signalling-3 in insulin-producing cells

A Permissive Role for Phosphatidylinositol 3-Kinase in the Stat5- mediated Expression of Cyclin D2 by the Interleukin-2 Receptor

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