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Mesto N, Movassat J, Tourrel-Cuzin C. P2-type purinergic signaling in the regulation of pancreatic β-cell functional plasticity as a promising novel therapeutic approach for the treatment of type 2 diabetes? Front Endocrinol (Lausanne) 2022; 13:1099152. [PMID: 37065173 PMCID: PMC10099247 DOI: 10.3389/fendo.2022.1099152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
Diabetes Mellitus is a metabolic disorder characterized by a chronic hyperglycemia due to an impaired insulin secretion and a decreased in peripheral insulin sensitivity. This disease is a major public health problem due to it sharp prevalence. Therefore, it is crucial to readapt therapeutic approaches for the treatment of this pathology. One of the strategies would be through P2-type purinergic receptors pathway via ATP binding. In addition to its well-known role as an intracellular energy intermediary in numerous biochemical and physiological processes, ATP is also an important extracellular signaling molecule. ATP mediates its effects by binding and activating two classes of P2 purinoreceptors: P2X receptors that are ligand-gated ion channel receptors, existing in seven isoforms (P2X 1 to 7) and P2Y receptors that are G-protein coupled receptors, existing in eight isoforms (P2Y 1/2/4/6/11/12/13/14). These receptors are ubiquitously distributed and involved in numerous physiological processes in several tissues. The concept of purinergic signaling, originally formulated by Geoffrey Burnstock (1929-2020), was also found to mediate various responses in the pancreas. Several studies have shown that P2 receptors are expressed in the endocrine pancreas, notably in β cells, where ATP could modulate their function but also their plasticity and thus play a physiological role in stimulating insulin secretion to face some metabolic demands. In this review, we provide a historical perspective and summarize current knowledge on P2-type purinergic signaling in the regulation of pancreatic β-cell functional plasticity, which would be a promising novel therapeutic approach for the treatment of type 2 diabetes.
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Mesto N, Bailbe D, Eskandar M, Pommier G, Gil S, Tolu S, Movassat J, Tourrel-Cuzin C. Involvement of P2Y signaling in the restoration of glucose-induced insulin exocytosis in pancreatic β cells exposed to glucotoxicity. J Cell Physiol 2021; 237:881-896. [PMID: 34435368 DOI: 10.1002/jcp.30564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/27/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022]
Abstract
Purinergic P2Y receptors, by binding adenosine triphosphate (ATP), are known for enhancing glucose-stimulated insulin secretion (GSIS) in pancreatic β cells. However, the impact of these receptors in the actin dynamics and insulin granule exocytosis in these cells is not established, neither in normal nor in glucotoxic environment. In this study, we investigate the involvement of P2Y receptors on the behavior of insulin granules and the subcortical actin network dynamics in INS-1 832/13 β cells exposed to normal or glucotoxic environment and their role in GSIS. Our results show that the activation of P2Y purinergic receptors by ATP or its agonist increase the insulin granules exocytosis and the reorganization of the subcortical actin network and participate in the potentiation of GSIS. In addition, their activation in INS-1832/13 β-cells, with impaired insulin secretion following exposure to elevated glucose levels, restores GSIS competence through the distal steps of insulin exocytosis. These results are confirmed ex vivo by perifusion experiments on islets from type 2 diabetic (T2D) Goto-Kakizaki (GK) rats. Indeed, the P2Y receptor agonist restores the altered GSIS, which is normally lost in this T2D animal model. Moreover, we observed an improvement of the glucose tolerance, following the acute intraperitoneal injection of the P2Y agonist concomitantly with glucose, in diabetic GK rats. All these data provide new insights into the unprecedented therapeutic role of P2Y purinergic receptors in the pathophysiology of T2D.
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Affiliation(s)
- Nour Mesto
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Danielle Bailbe
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Myriam Eskandar
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Gaëlle Pommier
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Stéphanie Gil
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France.,Université de Paris, UFR Sciences du Vivant (SDV), Paris, France
| | - Stefania Tolu
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Jamileh Movassat
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
| | - Cécile Tourrel-Cuzin
- 'Université de Paris' 'Unit of Functional and Adaptative Biology (BFA)', CNRS, UMR 8251, Team 'Biologie et Pathologie du Pancréas Endocrine', Paris, France
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Broca C, Varin E, Armanet M, Tourrel-Cuzin C, Bosco D, Dalle S, Wojtusciszyn A. Correction: proteasome dysfunction mediates high glucose-induced apoptosis in rodent Beta cells and human islets. PLoS One 2014; 9:e102652. [PMID: 25000098 PMCID: PMC4085027 DOI: 10.1371/journal.pone.0102652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
[This corrects the article DOI: 10.1371/journal.pone.0092066.].
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Broca C, Varin E, Armanet M, Tourrel-Cuzin C, Bosco D, Dalle S, Wojtusciszyn A. Proteasome dysfunction mediates high glucose-induced apoptosis in rodent beta cells and human islets. PLoS One 2014; 9:e92066. [PMID: 24642635 PMCID: PMC3958412 DOI: 10.1371/journal.pone.0092066] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/17/2014] [Indexed: 01/23/2023] Open
Abstract
The ubiquitin/proteasome system (UPS), a major cellular protein degradation machinery, plays key roles in the regulation of many cell functions. Glucotoxicity mediated by chronic hyperglycaemia is detrimental to the function and survival of pancreatic beta cells. The aim of our study was to determine whether proteasome dysfunction could be involved in beta cell apoptosis in glucotoxic conditions, and to evaluate whether such a dysfunction might be pharmacologically corrected. Therefore, UPS activity was measured in GK rats islets, INS-1E beta cells or human islets after high glucose and/or UPS inhibitor exposure. Immunoblotting was used to quantify polyubiquitinated proteins, endoplasmic reticulum (ER) stress through CHOP expression, and apoptosis through the cleavage of PARP and caspase-3, whereas total cell death was detected through histone-associated DNA fragments measurement. In vitro, we found that chronic exposure of INS-1E cells to high glucose concentrations significantly decreases the three proteasome activities by 20% and leads to caspase-3-dependent apoptosis. We showed that pharmacological blockade of UPS activity by 20% leads to apoptosis in a same way. Indeed, ER stress was involved in both conditions. These results were confirmed in human islets, and proteasome activities were also decreased in hyperglycemic GK rats islets. Moreover, we observed that a high glucose treatment hypersensitized beta cells to the apoptotic effect of proteasome inhibitors. Noteworthily, the decreased proteasome activity can be corrected with Exendin-4, which also protected against glucotoxicity-induced apoptosis. Taken together, our findings reveal an important role of proteasome activity in high glucose-induced beta cell apoptosis, potentially linking ER stress and glucotoxicity. These proteasome dysfunctions can be reversed by a GLP-1 analog. Thus, UPS may be a potent target to treat deleterious metabolic conditions leading to type 2 diabetes.
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Affiliation(s)
- Christophe Broca
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Elodie Varin
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Mathieu Armanet
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Cécile Tourrel-Cuzin
- B2PE Laboratory (Biology & Pathology of Endocrine Pancreas), BFA Unit, Univ. Paris-Diderot, CNRS EAC4413, Paris, France
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Stéphane Dalle
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Anne Wojtusciszyn
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
- Department of Endocrinology-Diabetes-Nutrition, University Hospital Lapeyronie, Montpellier, France
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Auffret J, Freemark M, Carré N, Mathieu Y, Tourrel-Cuzin C, Lombès M, Movassat J, Binart N. Defective prolactin signaling impairs pancreatic β-cell development during the perinatal period. Am J Physiol Endocrinol Metab 2013; 305:E1309-18. [PMID: 24064341 PMCID: PMC3840213 DOI: 10.1152/ajpendo.00636.2012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Prolactin (PRL) and placental lactogens stimulate β-cell replication and insulin production in pancreatic islets and insulinoma cells through binding to the PRL receptor (PRLR). However, the contribution of PRLR signaling to β-cell ontogeny and function in perinatal life and the effects of the lactogens on adaptive islet growth are poorly understood. We provide evidence that expansion of β-cell mass during both embryogenesis and the postnatal period is impaired in the PRLR(-/-) mouse model. PRLR(-/-) newborns display a 30% reduction of β-cell mass, consistent with reduced proliferation index at E18.5. PRL stimulates leucine incorporation and S6 kinase phosphorylation in INS-1 cells, supporting a role for β-cell mTOR signaling in PRL action. Interestingly, a defect in the development of acini is also observed in absence of PRLR signaling, with a sharp decline in cellular size in both endocrine and exocrine compartments. Of note, a decrease in levels of IGF-II, a PRL target, in the Goto-Kakizaki (GK) rat, a spontaneous model of type 2 diabetes, is associated with a lack of PRL-mediated β-cell proliferation in embryonic pancreatic buds. Reduced pancreatic IGF-II expression in both rat and mouse models suggests that this factor may constitute a molecular link between PRL signaling and cell ontogenesis. Together, these results provide evidence that PRL signaling is essential for pancreas ontogenesis during the critical perinatal window responsible for establishing functional β-cell reserve.
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Carneiro L, Allard C, Guissard C, Fioramonti X, Tourrel-Cuzin C, Bailbé D, Barreau C, Offer G, Nédelec E, Salin B, Rigoulet M, Belenguer P, Pénicaud L, Leloup C. Importance of mitochondrial dynamin-related protein 1 in hypothalamic glucose sensitivity in rats. Antioxid Redox Signal 2012; 17:433-44. [PMID: 22229526 DOI: 10.1089/ars.2011.4254] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS Hypothalamic mitochondrial reactive oxygen species (mROS)-mediated signaling has been recently shown to be involved in the regulation of energy homeostasis. However, the upstream signals that control this mechanism have not yet been determined. Here, we hypothesize that glucose-induced mitochondrial fission plays a significant role in mROS-dependent hypothalamic glucose sensing. RESULTS Glucose-triggered translocation of the fission protein dynamin-related protein 1 (DRP1) to mitochondria was first investigated in vivo in hypothalamus. Thus, we show that intracarotid glucose injection induces the recruitment of DRP1 to VMH mitochondria in vivo. Then, expression was transiently knocked down by intra-ventromedial hypothalamus (VMH) DRP1 siRNA (siDRP1) injection. 72 h post siRNA injection, brain intracarotid glucose induced insulin secretion, and VMH glucose infusion-induced refeeding decrease were measured, as well as mROS production. The SiDRP1 rats decreased mROS and impaired intracarotid glucose injection-induced insulin secretion. In addition, the VMH glucose infusion-induced refeeding decrease was lost in siDRP1 rats. Finally, mitochondrial function was evaluated by oxygen consumption measurements after DRP1 knock down. Although hypothalamic mitochondrial respiration was not modified in the resting state, substrate-driven respiration was impaired in siDRP1 rats and associated with an alteration of the coupling mechanism. INNOVATION AND CONCLUSION Collectively, our results suggest that glucose-induced DRP1-dependent mitochondrial fission is an upstream regulator for mROS signaling, and consequently, a key mechanism in hypothalamic glucose sensing. Thus, for the first time, we demonstrate the involvement of DRP1 in physiological regulation of brain glucose-induced insulin secretion and food intake inhibition. Such involvement implies DRP1-dependent mROS production.
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Affiliation(s)
- Lionel Carneiro
- Centre des Sciences du Goût et de l'Alimentation (CSGA), Université de Bourgogne, Dijon, France
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Boutant M, Ramos OHP, Tourrel-Cuzin C, Movassat J, Ilias A, Vallois D, Planchais J, Pégorier JP, Schuit F, Petit PX, Bossard P, Maedler K, Grapin-Botton A, Vasseur-Cognet M. COUP-TFII controls mouse pancreatic β-cell mass through GLP-1-β-catenin signaling pathways. PLoS One 2012; 7:e30847. [PMID: 22292058 PMCID: PMC3265526 DOI: 10.1371/journal.pone.0030847] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 12/23/2011] [Indexed: 12/25/2022] Open
Abstract
Background The control of the functional pancreatic β-cell mass serves the key homeostatic function of releasing the right amount of insulin to keep blood sugar in the normal range. It is not fully understood though how β-cell mass is determined. Methodology/Principal Findings Conditional chicken ovalbumin upstream promoter transcription factor II (COUP-TFII)-deficient mice were generated and crossed with mice expressing Cre under the control of pancreatic duodenal homeobox 1 (pdx1) gene promoter. Ablation of COUP-TFII in pancreas resulted in glucose intolerance. Beta-cell number was reduced at 1 day and 3 weeks postnatal. Together with a reduced number of insulin-containing cells in the ductal epithelium and normal β-cell proliferation and apoptosis, this suggests decreased β-cell differentiation in the neonatal period. By testing islets isolated from these mice and cultured β-cells with loss and gain of COUP-TFII function, we found that COUP-TFII induces the expression of the β-catenin gene and its target genes such as cyclin D1 and axin 2. Moreover, induction of these genes by glucagon-like peptide 1 (GLP-1) via β-catenin was impaired in absence of COUP-TFII. The expression of two other target genes of GLP-1 signaling, GLP-1R and PDX-1 was significantly lower in mutant islets compared to control islets, possibly contributing to reduced β-cell mass. Finally, we demonstrated that COUP-TFII expression was activated by the Wnt signaling-associated transcription factor TCF7L2 (T-cell factor 7-like 2) in human islets and rat β-cells providing a feedback loop. Conclusions/Significance Our findings show that COUP-TFII is a novel component of the GLP-1 signaling cascade that increases β-cell number during the neonatal period. COUP-TFII is required for GLP-1 activation of the β-catenin-dependent pathway and its expression is under the control of TCF7L2.
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Affiliation(s)
- Marie Boutant
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
| | - Oscar Henrique Pereira Ramos
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
| | - Cécile Tourrel-Cuzin
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
| | - Jamileh Movassat
- Unit of Functional and Adaptative Biology, Laboratory of Biology and Pathology of the Endocrine Pancreas, Paris Diderot University, Paris, France
| | - Anissa Ilias
- Unit of Functional and Adaptative Biology, Laboratory of Biology and Pathology of the Endocrine Pancreas, Paris Diderot University, Paris, France
| | - David Vallois
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Julien Planchais
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
| | - Jean-Paul Pégorier
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
| | - Frans Schuit
- Department of Molecular Cellular Biology, Leuven, Belgium
| | - Patrice X. Petit
- Centre national de la recherche scientifique (CNRS), Cochin Institute, Paris, France
| | - Pascale Bossard
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
| | - Kathrin Maedler
- Centre for Biomolecular Interactions Bremen, University of Bremen, Germany
| | | | - Mireille Vasseur-Cognet
- Institute national del santé et de la recherché medicale(INSERM), Department of Endocrinology, Metabolism and Cancer, Cochin Institute, Paris-France
- Centre national de la recherche scientifique (CNRS), Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
- * E-mail:
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Portha B, Lacraz G, Chavey A, Figeac F, Fradet M, Tourrel-Cuzin C, Homo-Delarche F, Giroix MH, Bailbé D, Gangnerau MN, Movassat J. Islet structure and function in the GK rat. Adv Exp Med Biol 2010; 654:479-500. [PMID: 20217511 DOI: 10.1007/978-90-481-3271-3_21] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Type 2 diabetes mellitus (T2D) arises when the endocrine pancreas fails to secrete sufficient insulin to cope with the metabolic demand because of beta-cell secretory dysfunction and/or decreased beta-cell mass. Defining the nature of the pancreatic islet defects present in T2D has been difficult, in part because human islets are inaccessible for direct study. This review is aimed to illustrate to what extent the Goto-Kakizaki rat, one of the best characterized animal models of spontaneous T2D, has proved to be a valuable tool offering sufficient commonalities to study this aspect. A comprehensive compendium of the multiple functional GK islet abnormalities so far identified is proposed in this perspective. The pathogenesis of defective beta-cell number and function in the GK model is also discussed. It is proposed that the development of T2D in the GK model results from the complex interaction of multiple events: (i) several susceptibility loci containing genes responsible for some diabetic traits (distinct loci encoding impairment of beta-cell metabolism and insulin exocytosis, but no quantitative trait locus for decreased beta-cell mass); (ii) gestational metabolic impairment inducing an epigenetic programming of the offspring pancreas (decreased beta-cell neogenesis and proliferation) transmitted over generations; and (iii) loss of beta-cell differentiation related to chronic exposure to hyperglycaemia/hyperlipidaemia, islet inflammation, islet oxidative stress, islet fibrosis and perturbed islet vasculature.
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Affiliation(s)
- Bernard Portha
- Laboratoire B2PE, Unité BFA, Université Paris-Diderot et CNRS EAC4413, F - 75205 Paris Cedex13, France.
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Karaca M, Castel J, Tourrel-Cuzin C, Brun M, Géant A, Dubois M, Catesson S, Rodriguez M, Luquet S, Cattan P, Lockhart B, Lang J, Ktorza A, Magnan C, Kargar C. Exploring functional beta-cell heterogeneity in vivo using PSA-NCAM as a specific marker. PLoS One 2009; 4:e5555. [PMID: 19440374 PMCID: PMC2679208 DOI: 10.1371/journal.pone.0005555] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 04/15/2009] [Indexed: 11/18/2022] Open
Abstract
Background The mass of pancreatic β-cells varies according to increases in insulin demand. It is hypothesized that functionally heterogeneous β-cell subpopulations take part in this process. Here we characterized two functionally distinct groups of β-cells and investigated their physiological relevance in increased insulin demand conditions in rats. Methods Two rat β-cell populations were sorted by FACS according to their PSA-NCAM surface expression, i.e. βhigh and βlow-cells. Insulin release, Ca2+ movements, ATP and cAMP contents in response to various secretagogues were analyzed. Gene expression profiles and exocytosis machinery were also investigated. In a second part, βhigh and βlow-cell distribution and functionality were investigated in animal models with decreased or increased β-cell function: the Zucker Diabetic Fatty rat and the 48 h glucose-infused rat. Results We show that β-cells are heterogeneous for PSA-NCAM in rat pancreas. Unlike βlow-cells, βhigh-cells express functional β-cell markers and are highly responsive to various insulin secretagogues. Whereas βlow-cells represent the main population in diabetic pancreas, an increase in βhigh-cells is associated with gain of function that follows sustained glucose overload. Conclusion Our data show that a functional heterogeneity of β-cells, assessed by PSA-NCAM surface expression, exists in vivo. These findings pinpoint new target populations involved in endocrine pancreas plasticity and in β-cell defects in type 2 diabetes.
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Affiliation(s)
- Melis Karaca
- Laboratoire de Physiopathologie de la Nutrition, Université Paris Diderot, CNRS UMR 7059, Paris, France.
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Costes S, Vandewalle B, Tourrel-Cuzin C, Broca C, Linck N, Bertrand G, Kerr-Conte J, Portha B, Pattou F, Bockaert J, Dalle S. Degradation of cAMP-responsive element-binding protein by the ubiquitin-proteasome pathway contributes to glucotoxicity in beta-cells and human pancreatic islets. Diabetes 2009; 58:1105-15. [PMID: 19223597 PMCID: PMC2671045 DOI: 10.2337/db08-0926] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 02/10/2009] [Indexed: 01/09/2023]
Abstract
OBJECTIVE In type 2 diabetes, chronic hyperglycemia is detrimental to beta-cells, causing apoptosis and impaired insulin secretion. The transcription factor cAMP-responsive element-binding protein (CREB) is crucial for beta-cell survival and function. We investigated whether prolonged exposure of beta-cells to high glucose affects the functional integrity of CREB. RESEARCH DESIGN AND METHODS INS-1E cells and rat and human islets were used. Gene expression was analyzed by RT-PCR and Western blotting. Apoptosis was detected by cleaved caspase-3 emergence, DNA fragmentation, and electron microscopy. RESULTS Chronic exposure of INS-1E cells and rat and human islets to high glucose resulted in decreased CREB protein expression, phosphorylation, and transcriptional activity associated with apoptosis and impaired beta-cell function. High-glucose treatment increased CREB polyubiquitination, while treatment of INS-1E cells with the proteasome inhibitor MG-132 prevented the decrease in CREB content. The emergence of apoptosis in INS-1E cells with decreased CREB protein expression knocked down by small interfering RNA suggested that loss of CREB protein content induced by high glucose contributes to beta-cell apoptosis. Loading INS-1E cells or human islets with a cell-permeable peptide mimicking the proteasomal targeting sequence of CREB blocked CREB degradation and protected INS-1E cells and human islets from apoptosis induced by high glucose. The insulin secretion in response to glucose and the insulin content were preserved in human islets exposed to high glucose and loaded with the peptide. CONCLUSIONS These studies demonstrate that the CREB degradation by the ubiquitin-proteasome pathway contributes to beta-cell dysfunction and death upon glucotoxicity and provide new insight into the cellular mechanisms of glucotoxicity.
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Affiliation(s)
- Safia Costes
- Institut National de la Santé et de la Recherche Médicale (INSERM), U661, Equipe Avenir, Institut de Génomique Fonctionnelle, Montpellier, France
- Centre National de la Recherche Scientifique (CNRS), UMR5203, Université Montpellier (IFR3), Montpellier, France
| | | | | | - Christophe Broca
- Institut National de la Santé et de la Recherche Médicale (INSERM), U661, Equipe Avenir, Institut de Génomique Fonctionnelle, Montpellier, France
- Centre National de la Recherche Scientifique (CNRS), UMR5203, Université Montpellier (IFR3), Montpellier, France
| | - Nathalie Linck
- Institut National de la Santé et de la Recherche Médicale (INSERM), U661, Equipe Avenir, Institut de Génomique Fonctionnelle, Montpellier, France
- Centre National de la Recherche Scientifique (CNRS), UMR5203, Université Montpellier (IFR3), Montpellier, France
| | - Gyslaine Bertrand
- Institut National de la Santé et de la Recherche Médicale (INSERM), U661, Equipe Avenir, Institut de Génomique Fonctionnelle, Montpellier, France
- Centre National de la Recherche Scientifique (CNRS), UMR5203, Université Montpellier (IFR3), Montpellier, France
| | | | | | | | - Joel Bockaert
- Institut National de la Santé et de la Recherche Médicale (INSERM), U661, Equipe Avenir, Institut de Génomique Fonctionnelle, Montpellier, France
- Centre National de la Recherche Scientifique (CNRS), UMR5203, Université Montpellier (IFR3), Montpellier, France
| | - Stéphane Dalle
- Institut National de la Santé et de la Recherche Médicale (INSERM), U661, Equipe Avenir, Institut de Génomique Fonctionnelle, Montpellier, France
- Centre National de la Recherche Scientifique (CNRS), UMR5203, Université Montpellier (IFR3), Montpellier, France
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Leloup C, Tourrel-Cuzin C, Magnan C, Karaca M, Castel J, Carneiro L, Colombani AL, Ktorza A, Casteilla L, Pénicaud L. Mitochondrial reactive oxygen species are obligatory signals for glucose-induced insulin secretion. Diabetes 2009; 58:673-81. [PMID: 19073765 PMCID: PMC2646066 DOI: 10.2337/db07-1056] [Citation(s) in RCA: 253] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Insulin secretion involves complex events in which the mitochondria play a pivotal role in the generation of signals that couple glucose detection to insulin secretion. Studies on the mitochondrial generation of reactive oxygen species (ROS) generally focus on chronic nutrient exposure. Here, we investigate whether transient mitochondrial ROS production linked to glucose-induced increased respiration might act as a signal for monitoring insulin secretion. RESEARCH DESIGN AND METHODS ROS production in response to glucose was investigated in freshly isolated rat islets. ROS effects were studied using a pharmacological approach and calcium imaging. RESULTS Transient glucose increase from 5.5 to 16.7 mmol/l stimulated ROS generation, which was reversed by antioxidants. Insulin secretion was dose dependently blunted by antioxidants and highly correlated with ROS levels. The incapacity of beta-cells to secrete insulin in response to glucose with antioxidants was associated with a decrease in ROS production and in contrast to the maintenance of high levels of ATP and NADH. Then, we investigated the mitochondrial origin of ROS (mROS) as the triggering signal. Insulin release was mimicked by the mitochondrial-complex blockers, antimycin and rotenone, that generate mROS. The adding of antioxidants to mitochondrial blockers or to glucose was used to lower mROS reversed insulin secretion. Finally, calcium imaging on perifused islets using glucose stimulation or mitochondrial blockers revealed that calcium mobilization was completely reversed using the antioxidant trolox and that it was of extracellular origin. No toxic effects were present using these pharmacological approaches. CONCLUSIONS Altogether, these complementary results demonstrate that mROS production is a necessary stimulus for glucose-induced insulin secretion.
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Affiliation(s)
- Corinne Leloup
- Department of Metabolism, Plasticity, and Mitochondria, Unité Mixte de Recherche 5241, Centre National de la Recherche Scientifique-Université Paul Sabatier, Institut Fédératif de Recherche 31, Toulouse, France.
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Portha B, Lacraz G, Kergoat M, Homo-Delarche F, Giroix MH, Bailbé D, Gangnerau MN, Dolz M, Tourrel-Cuzin C, Movassat J. The GK rat beta-cell: a prototype for the diseased human beta-cell in type 2 diabetes? Mol Cell Endocrinol 2009; 297:73-85. [PMID: 18640239 DOI: 10.1016/j.mce.2008.06.013] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2008] [Revised: 06/03/2008] [Accepted: 06/12/2008] [Indexed: 02/01/2023]
Abstract
Increasing evidence indicates that decreased functional beta-cell mass is the hallmark of type 2 diabetes (T2D) mellitus. Nowadays, the debate focuses on the possible mechanisms responsible for abnormal islet microenvironment, decreased beta-cell number, impaired beta-cell function, and their multifactorial aetiologies. This review is aimed to illustrate to what extend the Goto-Kakizaki rat, one of the best characterized animal models of spontaneous T2D, has proved be a valuable tool offering sufficient commonalities to study these aspects. We propose that the defective beta-cell mass and function in the GK model reflect the complex interactions of multiple pathogenic players: (i) several independent loci containing genes responsible for some diabetic traits (but not decreased beta-cell mass); (ii) gestational metabolic impairment inducing an epigenetic programming of the pancreas (decreased beta-cell neogenesis and/or proliferation) which is transmitted to the next generation; and (iii) loss of beta-cell differentiation due to chronic exposure to hyperglycemia/hyperlipidemia, inflammatory mediators, oxidative stress and to perturbed islet microarchitecture.
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Affiliation(s)
- B Portha
- Groupe Biologie et Pathologie du Pancréas Endocrine, Laboratoire de Physiopathologie de la Nutrition, UMR CNRS 7059, Université Paris-Diderot/UP7, Paris, France.
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Karaca M, Durel B, Languille L, Lamotte L, Tourrel-Cuzin C, Leroux L, Abou Sleymane G, Saint-Just S, Bucchini D, Ktorza A, Joshi RL. Transgenic expression of human INS gene in Ins1/Ins2 double knockout mice leads to insulin underproduction and diabetes in some male mice. FRONT BIOSCI-LANDMRK 2007; 12:1586-93. [PMID: 17127405 DOI: 10.2741/2171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have generated transgenic mouse lines expressing exclusively a human INS transgene on an Ins1/Ins2 double knockout (mIKO) background. The transgene expression was driven by either a 4000 bp or a 353 bp promoter. These transgenic lines, designated mIKO:INS4000 and mIKO:INS353, were viable and fertile. Determination of the amounts of insulin transcripts and total pancreatic insulin content revealed relative insulin underproduction in both lines, from birth to adulthood. Total pancreatic insulin stores in mIKO:INS4000 and mIKO:INS353 mice represented only about 50% and 27%, respectively, as compared to wild-type mice. Morphometric analysis of pancreas did not show any compensatory beta-cell hyperplasia. The majority of animals in both lines remained normoglycemic throughout their lives. Nevertheless, glucose tolerance tests revealed glucose intolerance in nearly half of mIKO:INS4000 male mice, likely due to impaired insulin secretion detected in those animals. In addition, a small fraction (2-4%) of male mice in both lines spontaneously developed diabetes with very distinct pathophysiological features. Diabetes was never seen in female animals. The diabetes developed by mIKO:INS353 mice was rapidly lethal, accompanied by a dramatic depletion of pancreatic insulin stores whereas the mIKO:INS4000 diabetic animals could live for several months. This suggests a possible link between the structure of the human INS gene promoter and the type of diabetes developed in these lines.
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Affiliation(s)
- Melis Karaca
- Department of Genetics and Development, Institut Cochin, INSERM U567, CNRS UMR 8104, Université René Descartes Paris 5, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
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Abstract
β-cell neogenesis triggers the generation of new β-cells
from precursor cells. Neogenesis from duct epithelium is the
most currently described and the best documented process
of differentiation of precursor cells into β-cells. It is contributes
not only to β-cell mass expansion during fetal and
nonatal life but it is also involved in the maintenance of the
β-cell mass in adults. It is also required for the increase in
β-cell mass in situations of increase insulin demand (obesity,
pregnancy). A large number of factors controlling the differentiation
of β-cells has been identified. They are classified
into the following main categories: growth factors, cytokine
and inflamatory factors, and hormones such as PTHrP and
GLP-1. The fact that intestinal incretin hormone GLP-1
exerts a major trophic role on pancreatic β-cells provides
insights into the possibility to pharmacologically stimulate
β-cell neogenesis. This could have important implications
for the of treatment of type 1 and type 2 diabetes. Transdifferentiation,
that is, the differentiation of already differentiated
cells into β-cells, remains controversial.However, more
and more studies support this concept. The cells, which can
potentially “transdifferentiate” into β-cells, can belong to
the pancreas (acinar cells) and even islets, or originate from
extra-pancreatic tissues such as the liver. Neogenesis from intra-islet precursors also have been proposed and subpopulations
of cell precursors inside islets have been described
by some authors. Nestin positive cells, which have been considered
as the main candidates, appear rather as progenitors
of endothelial cells rather than β-cells and contribute to
angiogenesis rather than neogenesis. To take advantage of
the different differentiation processes may be a direction for
future cellular therapies. Ultimately, a better understanding
of the molecular mechanisms involved in β-cell neogenesis
will allow us to use any type of differentiated and/or undifferentiated
cells as a source of potential cell precursors.
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Affiliation(s)
- Maryline Paris
- Laboratoire de Physiopathologie de la Nutrition, Universite Paris 7, Paris, France
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