scholarly journals Identification of a small molecule that stimulates human β-cell proliferation and insulin secretion, and protects against cytotoxic stress in rat insulinoma cells

2019 ◽  
Author(s):  
Hans E. Hohmeier ◽  
Lu Zhang ◽  
Brandon Taylor ◽  
Samuel Stephens ◽  
Peter McNamara ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Small Molecule ◽  
Islet Cell ◽  
Human Islet ◽  
Luciferase Reporter ◽  
Β Cell ◽  
Cytotoxic Stress ◽  
Insulinoma Cells ◽  
Rat Insulinoma

AbstractA key event in the development of both major forms of diabetes is the loss of functional pancreatic islet β-cell mass. Strategies aimed at enhancing β-cell regeneration have long been pursued, but methods for reliably inducing human β-cell proliferation with full retention of key functions such as glucose-stimulated insulin secretion (GSIS) are still very limited. We have previously reported that overexpression of the homeobox transcription factor Nkx6.1 stimulates β-cell proliferation, while also enhancing GSIS and providing protection against β-cell cytotoxicity through induction of the VGF prohormone. We developed an Nkx6.1 pathway screen by stably transfecting 832/13 rat insulinoma cells with a VGF promoter-luciferase reporter construct, using the resultant cell line to screen a 630,000 compound chemical library. We isolated three compounds with consistent effects to stimulate human islet cell proliferation. Further studies of the most potent of these compounds, GNF-9228, revealed that it selectively activates human β-cell relative to α-cell proliferation and has no effect on δ-cell replication. In addition, pre-treatment, but not short term exposure of human islets to GNF-9228 enhances GSIS. GNF-9228 also protects 832/13 insulinoma cells against ER stress- and inflammatory cytokine-induced cytotoxicity. In contrast to recently emergent Dyrk1a inhibitors that stimulate human islet cell proliferation, GNF-9228 does not activate NFAT translocation. These studies have led to identification of a small molecule with pleiotropic positive effects on islet biology, including stimulation of human β-cell proliferation and insulin secretion, and protection against multiple agents of cytotoxic stress.

scholarly journals Identification of a small molecule that stimulates human β-cell proliferation and insulin secretion, and protects against cytotoxic stress in rat insulinoma cells

PLoS ONE ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. e0224344 ◽  
Author(s):  
Hans E. Hohmeier ◽  
Lu Zhang ◽  
Brandon Taylor ◽  
Samuel Stephens ◽  
Danhong Lu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Small Molecule ◽  
Β Cell ◽  
Cytotoxic Stress ◽  
Insulinoma Cells ◽  
Rat Insulinoma

scholarly journals A Pdx-1-Regulated Soluble Factor Activates Rat and Human Islet Cell Proliferation

2016 ◽  
Vol 36 (23) ◽  
pp. 2918-2930 ◽  
Author(s):  
Heather L. Hayes ◽  
Lu Zhang ◽  
Thomas C. Becker ◽  
Jonathan M. Haldeman ◽  
Samuel B. Stephens ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Islet Cell ◽  
Transforming Growth Factor ◽  
Cell Function ◽  
Transforming Growth Factor Β ◽  
Human Islet ◽  
Soluble Factor ◽  
Β Cells ◽  
Β Cell ◽  
Insulin Promoter

The homeodomain transcription factor Pdx-1 has important roles in pancreas and islet development as well as in β-cell function and survival. We previously reported that Pdx-1 overexpression stimulates islet cell proliferation, but the mechanism remains unclear. Here, we demonstrate that overexpression of Pdx-1 triggers proliferation largely by a non-cell-autonomous mechanism mediated by soluble factors. Consistent with this idea, overexpression of Pdx-1 under the control of a β-cell-specific promoter (rat insulin promoter [RIP]) stimulates proliferation of both α and β cells, and overexpression of Pdx-1 in islets separated by a Transwell membrane from islets lacking Pdx-1 overexpression activates proliferation in the untreated islets. Microarray and gene ontology (GO) analysis identified inhibin beta-B (Inhbb), an activin subunit and member of the transforming growth factor β (TGF-β) superfamily, as a Pdx-1-responsive gene. Overexpression of Inhbb or addition of activin B stimulates rat islet cell and β-cell proliferation, and the activin receptors RIIA and RIIB are required for the full proliferative effects of Pdx-1 in rat islets. In human islets, Inhbb overexpression stimulates total islet cell proliferation and potentiates Pdx-1-stimulated proliferation of total islet cells and β cells. In sum, this study identifies a mechanism by which Pdx-1 induces a soluble factor that is sufficient to stimulate both rat and human islet cell proliferation.

scholarly journals Extracellular CADM1 interactions influence insulin secretion by rat and human islet β-cells and promote clustering of syntaxin-1

2016 ◽  
Vol 310 (11) ◽  
pp. E874-E885 ◽  
Author(s):  
Charles Zhang ◽  
Thomas A. Caldwell ◽  
M. Reza Mirbolooki ◽  
Diana Duong ◽  
Eun Jee Park ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Protein Interactions ◽  
Network Formation ◽  
Cell Function ◽  
Human Islet ◽  
Cell Contact ◽  
Β Cells ◽  
Β Cell ◽  
Β Cell Function ◽  
Insulinoma Cells

Contact between β-cells is necessary for their normal function. Identification of the proteins mediating the effects of β-cell-to-β-cell contact is a necessary step toward gaining a full understanding of the determinants of β-cell function and insulin secretion. The secretory machinery of the β-cells is nearly identical to that of central nervous system (CNS) synapses, and we hypothesize that the transcellular protein interactions that drive maturation of the two secretory machineries upon contact of one cell (or neural process) with another are also highly similar. Two such transcellular interactions, important for both synaptic and β-cell function, have been identified: EphA/ephrin-A and neuroligin/neurexin. Here, we tested the role of another synaptic cleft protein, CADM1, in insulinoma cells and in rat and human islet β-cells. We found that CADM1 is a predominant CADM isoform in β-cells. In INS-1 cells and primary β-cells, CADM1 constrains insulin secretion, and its expression decreases after prolonged glucose stimulation. Using a coculture model, we found that CADM1 also influences insulin secretion in a transcellular manner. We asked whether extracellular CADM1 interactions exert their influence via the same mechanisms by which they influence neurotransmitter exocytosis. Our results suggest that, as in the CNS, CADM1 interactions drive exocytic site assembly and promote actin network formation. These results support the broader hypothesis that the effects of cell-cell contact on β-cell maturation and function are mediated by the same extracellular protein interactions that drive the formation of the presynaptic exocytic machinery. These interactions may be therapeutic targets for reversing β-cell dysfunction in diabetes.

scholarly journals Orexin A Affects INS-1 Rat Insulinoma Cell Proliferation via Orexin Receptor 1 and the AKT Signaling Pathway

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Li Chen ◽  
Yuyan Zhao ◽  
Delu Zheng ◽  
Shujing Ju ◽  
Yang Shen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Signaling Pathway ◽  
Caspase 3 ◽  
Apoptotic Cell ◽  
Orexin A ◽  
Beta Cell Line ◽  
Insulinoma Cells ◽  
Rat Insulinoma

Our aim is to investigate the role of the AKT/PKB (protein kinase B) signaling pathway acting via orexin receptor 1 (OX1R) and the effects of orexin A (OXA) on cell proliferation in the insulin-secreting beta-cell line (INS-1 cells). Rat INS-1 cells were exposed to different concentrations of OXAin vitroand treated with OX1R antagonist (SB334867), PI3K antagonist (wortmannin), AKT antagonist (PF-04691502), or negative control. INS-1 amount of cell proliferation, viability and apoptosis, insulin secretion, OX1R protein expression, caspase-3 activity, and AKT protein levels were determined. We report that OXA (10-10to10-6 M) stimulates INS-1 cell proliferation and viability, reduces the proapoptotic activity of caspase-3 to protect against apoptotic cell death, and increases insulin secretion. Additionally, AKT phosphorylation was stimulated by OXA (10-10to10-6 M). However, the OX1R antagonist SB334867 (10-6 M), the PI3K antagonist wortmannin (10-8 M), the AKT antagonist PF-04691502 (10-6 M), or the combination of both abolished the effects of OXA to a certain extent. These results suggest that the upregulation of OXA-OX1R mediated by AKT activation may inhibit cell apoptosis and promote cell proliferation in INS-1 cells. This finding provides functional evidence of the biological actions of OXA in rat insulinoma cells.

scholarly journals Vitamin B6 deficiency disrupts serotonin signaling in pancreatic islets and induces gestational diabetes in mice

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ashley M. Fields ◽  
Kevin Welle ◽  
Elaine S. Ho ◽  
Clementina Mesaros ◽  
Martha Susiarjo
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Pancreatic Islets ◽  
Glucose Intolerance ◽  
Vitamin B6 ◽  
Serotonin Receptor ◽  
Dependent Manner ◽  
Β Cell ◽  
Vitamin B6 Deficiency ◽  
Maternal Glucose

AbstractIn pancreatic islets, catabolism of tryptophan into serotonin and serotonin receptor 2B (HTR2B) activation is crucial for β-cell proliferation and maternal glucose regulation during pregnancy. Factors that reduce serotonin synthesis and perturb HTR2B signaling are associated with decreased β-cell number, impaired insulin secretion, and gestational glucose intolerance in mice. Albeit the tryptophan-serotonin pathway is dependent on vitamin B6 bioavailability, how vitamin B6 deficiency impacts β-cell proliferation during pregnancy has not been investigated. In this study, we created a vitamin B6 deficient mouse model and investigated how gestational deficiency influences maternal glucose tolerance. Our studies show that gestational vitamin B6 deficiency decreases serotonin levels in maternal pancreatic islets and reduces β-cell proliferation in an HTR2B-dependent manner. These changes were associated with glucose intolerance and insulin resistance, however insulin secretion remained intact. Our findings suggest that vitamin B6 deficiency-induced gestational glucose intolerance involves additional mechanisms that are complex and insulin independent.

scholarly journals Ontology of the apelinergic system in mouse pancreas during pregnancy and relationship with β-cell mass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brenda Strutt ◽  
Sandra Szlapinski ◽  
Thineesha Gnaneswaran ◽  
Sarah Donegan ◽  
Jessica Hill ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Glucose Transporter ◽  
Cell Mass ◽  
Elevated Serum ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Glucose Transporter 2 ◽  
Glucose Stimulated Insulin Secretion

AbstractThe apelin receptor (Aplnr) and its ligands, Apelin and Apela, contribute to metabolic control. The insulin resistance associated with pregnancy is accommodated by an expansion of pancreatic β-cell mass (BCM) and increased insulin secretion, involving the proliferation of insulin-expressing, glucose transporter 2-low (Ins+Glut2LO) progenitor cells. We examined changes in the apelinergic system during normal mouse pregnancy and in pregnancies complicated by glucose intolerance with reduced BCM. Expression of Aplnr, Apelin and Apela was quantified in Ins+Glut2LO cells isolated from mouse pancreata and found to be significantly higher than in mature β-cells by DNA microarray and qPCR. Apelin was localized to most β-cells by immunohistochemistry although Aplnr was predominantly associated with Ins+Glut2LO cells. Aplnr-staining cells increased three- to four-fold during pregnancy being maximal at gestational days (GD) 9–12 but were significantly reduced in glucose intolerant mice. Apelin-13 increased β-cell proliferation in isolated mouse islets and INS1E cells, but not glucose-stimulated insulin secretion. Glucose intolerant pregnant mice had significantly elevated serum Apelin levels at GD 9 associated with an increased presence of placental IL-6. Placental expression of the apelinergic axis remained unaltered, however. Results show that the apelinergic system is highly expressed in pancreatic β-cell progenitors and may contribute to β-cell proliferation in pregnancy.

scholarly journals Deficiency of VCP-Interacting Membrane Selenoprotein (VIMP) Leads to G1 Cell Cycle Arrest and Cell Death in MIN6 Insulinoma Cells

2018 ◽  
Vol 51 (5) ◽  
pp. 2185-2197 ◽  
Author(s):  
Lili Men ◽  
Juan Sun ◽  
Decheng Ren
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Insulin Secretion ◽  
Cell Apoptosis ◽  
Β Cells ◽  
Β Cell ◽  
Cycle Arrest ◽  
G1 Cell Cycle Arrest ◽  
Insulinoma Cells

Background/Aims: VCP-interacting membrane selenoprotein (VIMP), an ER resident selenoprotein, is highly expressed in β-cells, however, the role of VIMP in β-cells has not been characterized. In this study, we studied the relationship between VIMP deficiency and β-cell survival in MIN6 insulinoma cells. Methods: To determine the role of VIMP in β-cells, lentiviral VIMP shRNAs were used to knock down (KD) expression of VIMP in MIN6 cells. Cell death was quantified by propidium iodide (PI) staining followed by flow cytometric analyses using a FACS Caliber and FlowJo software. Cell apoptosis and proliferation were determined by TUNEL assay and Ki67 staining, respectively. Cell cycle was analyzed after PI staining. Results: The results show that 1) VIMP suppression induces β-cell apoptosis, which is associated with a decrease in Bcl-xL, and the β-cell apoptosis induced by VIMP suppression can be inhibited by overexpression of Bcl-xL; 2) VIMP knockdown (KD) decreases cell proliferation and G1 cell cycle arrest by accumulating p27 and decreasing E2F1; 3) VIMP KD suppresses unfolded protein response (UPR) activation by regulating the IRE1α and PERK pathways; 4) VIMP KD increases insulin secretion. Conclusion: These results suggest that VIMP may function as a novel regulator to modulate β-cell survival, proliferation, cell cycle, UPR and insulin secretion in MIN6 cells.

scholarly journals The regulator of G-protein signaling RGS16 promotes insulin secretion and β-cell proliferation in rodent and human islets

2016 ◽  
Vol 5 (10) ◽  
pp. 988-996 ◽  
Author(s):  
Kevin Vivot ◽  
Valentine S. Moullé ◽  
Bader Zarrouki ◽  
Caroline Tremblay ◽  
Arturo D. Mancini ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
G Protein ◽  
Human Islets ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Β Cell

scholarly journals miR-29a Negatively Affects Glucose-Stimulated Insulin Secretion and MIN6 Cell Proliferation via Cdc42/β-Catenin Signaling

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Jing Duan ◽  
Xian-Ling Qian ◽  
Jun Li ◽  
Xing-Hua Xiao ◽  
Xiang-Tong Lu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
High Glucose ◽  
Cell Counting ◽  
Luciferase Reporter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Glucose Stimulation ◽  
Inhibition Of Proliferation ◽  
Glucose Stimulated Insulin Secretion

Background. Diabetes is a progressive metabolic disease characterized by hyperglycemia. Functional impairment of islet β cells can occur to varying degrees. This impairment can initially be compensated for by proliferation and metabolic changes of β cells. Cell division control protein 42 (Cdc42) and the microRNA (miRNA) miR-29 have important roles in β-cell proliferation and glucose-stimulated insulin secretion (GSIS), which we further explored using the mouse insulinoma cell line MIN6. Methods. Upregulation and downregulation of miR-29a and Cdc42 were accomplished using transient transfection. miR-29a and Cdc42 expression was detected by real-time PCR and western blotting. MIN6 proliferation was detected using a cell counting kit assay. GSIS under high-glucose (20.0 mM) or basal-glucose (5.0 mM) stimulation was detected by enzyme-linked immunosorbent assay. The miR-29a binding site in the Cdc42 mRNA 3′-untranslated region (UTR) was determined using bioinformatics and luciferase reporter assays. Results. miR-29a overexpression inhibited proliferation (P<0.01) and GSIS under high-glucose stimulation (P<0.01). Cdc42 overexpression promoted proliferation (P<0.05) and GSIS under high-glucose stimulation (P<0.05). miR-29a overexpression decreased Cdc42 expression (P<0.01), whereas miR-29a downregulation increased Cdc42 expression (P<0.01). The results showed that the Cdc42 mRNA 3′-UTR is a direct target of miR-29a in vitro. Additionally, Cdc42 reversed miR-29a-mediated inhibition of proliferation and GSIS (P<0.01). Furthermore, miR-29a inhibited β-catenin expression (P<0.01), whereas Cdc42 promoted β-catenin expression (P<0.01). Conclusion. By negatively regulating Cdc42 and the downstream molecule β-catenin, miR-29a inhibits MIN6 proliferation and insulin secretion.

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