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Polino AJ, Ng XW, Rooks R, Piston DW. Disrupting actin filaments enhances glucose-stimulated insulin secretion independent of the cortical actin cytoskeleton. J Biol Chem 2023; 299:105334. [PMID: 37827287 PMCID: PMC10641669 DOI: 10.1016/j.jbc.2023.105334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/17/2023] [Accepted: 10/02/2023] [Indexed: 10/14/2023] Open
Abstract
Just under the plasma membrane of most animal cells lies a dense meshwork of actin filaments called the cortical cytoskeleton. In insulin-secreting pancreatic β cells, a long-standing model posits that the cortical actin layer primarily acts to restrict access of insulin granules to the plasma membrane. Here we test this model and find that stimulating β cells with pro-secretory stimuli (glucose and/or KCl) has little impact on the cortical actin layer. Chemical perturbations of actin polymerization, by either disrupting or enhancing filamentation, dramatically enhance glucose-stimulated insulin secretion. Using scanning electron microscopy, we directly visualize the cortical cytoskeleton, allowing us to validate the effect of these filament-disrupting chemicals. We find the state of the cortical actin layer does not correlate with levels of insulin secretion, suggesting filament disruptors act on insulin secretion independently of the cortical cytoskeleton.
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Affiliation(s)
- Alexander J Polino
- Department of Cell Biology & Physiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Xue Wen Ng
- Department of Cell Biology & Physiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Rebecca Rooks
- Department of Cell Biology & Physiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology & Physiology, Washington University School of Medicine, St Louis, Missouri, USA.
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Polino AJ, Wen Ng X, Rooks R, Piston DW. Disrupting actin filaments enhances glucose-stimulated insulin secretion independent of the cortical actin cytoskeleton. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.15.549141. [PMID: 37502863 PMCID: PMC10369950 DOI: 10.1101/2023.07.15.549141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Just under the plasma membrane of most animal cells lies a dense meshwork of actin filaments called the cortical cytoskeleton. In insulin-secreting pancreatic β cells, a longstanding model posits that the cortical actin layer primarily acts to restrict access of insulin granules to the plasma membrane. Here we test this model and find that stimulating β cells with pro-secretory stimuli (glucose and/or KCl) has little impact on the cortical actin layer. Chemical perturbations of actin polymerization, by either disrupting or enhancing filamentation, dramatically enhances glucose-stimulated insulin secretion. We find that this enhancement does not correlate with the state of the cortical actin layer, suggesting filament disruptors act on insulin secretion independently of the cortical cytoskeleton.
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Affiliation(s)
| | | | | | - David W. Piston
- Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Al-Romaiyan A, Masocha W, Oyedemi S, Marafie SK, Huang GC, Jones PM, Persaud SJ. Commiphora myrrha stimulates insulin secretion from β-cells through activation of atypical protein kinase C and mitogen-activated protein kinase. JOURNAL OF ETHNOPHARMACOLOGY 2023; 302:115937. [PMID: 36410575 DOI: 10.1016/j.jep.2022.115937] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/22/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ayurvedic medicine has been used in the treatment of diabetes mellitus for centuries. In Arabia and some areas of Africa, Commiphora myrrha (CM) has been extensively used as a plant-based remedy. We have previously shown that an aqueous CM resin solution directly stimulates insulin secretion from MIN6 cells, a mouse β-cell line, and isolated mouse and human islets. However, the signaling pathways involved in CM-induced insulin secretion are completely unknown. Insulin secretion is normally triggered by elevations in intracellular Ca2+ ([Ca2+]i) through voltage gated Ca2+ channels (VGCC) and activation of protein kinases. Protein and lipid kinases such as protein kinase A (PKA), Ca2+-calmodulin dependent protein kinase II (CaMKII), phosphoinositide 3-kinases (PI3Ks), protein kinase C (PKC) and mitogen-activated protein kinase (MAPK), specifically extracellular signal-regulated kinases (ERK1/2), may be involved in receptor-operated insulin secretion. Therefore, we hypothesized that CM may induce insulin secretion by modulating the activity of VGCC and/or one or more of the above kinases. AIM OF THE STUDY To investigate the possible molecular mechanism of action of CM-induced insulin secretion. The effects of aqueous CM resin extract on [Ca2+]i and protein kinase activation from β-cells were examined. METHODS The effect of aqueous CM resin solution on [Ca2+]i was assessed using Ca2+ microfluorimetry. The involvement of VGCC in CM-induced insulin secretion was investigated using static and perifusion insulin secretion experiments in the presence of either EGTA, a Ca2+ chelator, or nifedipine, a blocker of VGCC. The involvement of kinase activation in the stimulatory effect of CM on insulin secretion was examined by using static and perifusion insulin secretion experiments in the presence of known pharmacological inhibitors and/or downregulation of specific kinases. The effects of CM on phosphorylation of PKCζ and ERK1/2 were also assessed using the Wes™ capillary-based protein electrophoresis. RESULTS Ca2+ microfluorimetry measurements showed that exposing MIN6 cells to CM (0.5-2 mg/mL) was not associated with changes in [Ca2+]i. Similarly, incubating MIN6 cells and mouse islets with EGTA and nifedipine, respectively, did not attenuate the insulin secretion induced by CM. However, incubating mouse and human islets with CM in the presence of staurosporine, a non-selective protein kinase inhibitor, completely blocked the effect of CM on insulin secretion. Exposing mouse islets to CM in the presence of H89, KN62 and LY294002, inhibitors of PKA, CaMKII and PI3K, respectively, did not reduce CM-induced insulin secretion. However, incubating mouse and human islets with CM in the presence of Ro 31-8220, a pan-PKC inhibitor, diminished insulin secretion stimulated by CM, whereas inhibiting the action of typical PKC (with Go6976) and PLCβ (with U73122) did not affect CM-stimulated insulin secretion. Similarly, downregulating typical and novel PKC by chronic exposure of mouse islets to phorbol 12-myristate 13-acetate (PMA) was also not associated with a decrease in the stimulatory effect of CM on insulin secretion. Interestingly, CM-induced insulin secretion from mouse islets was inhibited in the presence of the PKCζ inhibitor ZIP and a MAPK inhibitor PD 98059. In addition, Wes™ capillary-based protein electrophoresis indicated that expression of the phosphorylated forms of PKCζ and ERK1/2, a MAPK, was significantly increased following exposure of INS-1832/13 cells, a rat insulinoma cell line, to CM. CONCLUSIONS Our data indicate that CM directly stimulates insulin secretion through activating known downstream effectors of insulin-stimulus secretion coupling. Indeed, the increase in insulin secretion seen with CM is independent of changes in [Ca2+]i and does not involve activation of VGCC. Instead, the CM stimulatory effect on insulin secretion is completely dependent on protein kinase activation. Our findings indicate that CM could induce insulin exocytosis by stimulating the phosphorylation and activation of PKCζ, which in turn phosphorylates and activates ERK1/2.
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Affiliation(s)
- Altaf Al-Romaiyan
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait.
| | - Willias Masocha
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait.
| | - Sunday Oyedemi
- School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK.
| | - Sulaiman K Marafie
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Kuwait.
| | - Guo-Cai Huang
- Department of Diabetes, School of Cardiovascular Medicine &Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
| | - Peter M Jones
- Department of Diabetes, School of Cardiovascular Medicine &Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
| | - Shanta J Persaud
- Department of Diabetes, School of Cardiovascular Medicine &Sciences, Faculty of Life Sciences and Medicine, King's College London, UK.
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Salazar-Petres ER, Sferruzzi-Perri AN. Pregnancy-induced changes in β-cell function: what are the key players? J Physiol 2021; 600:1089-1117. [PMID: 33704799 DOI: 10.1113/jp281082] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Maternal metabolic adaptations during pregnancy ensure appropriate nutrient supply to the developing fetus. This is facilitated by reductions in maternal peripheral insulin sensitivity, which enables glucose to be available in the maternal circulation for transfer to the fetus for growth. To balance this process and avoid excessive hyperglycaemia and glucose intolerance in the mother during pregnancy, maternal pancreatic β-cells undergo remarkable changes in their function including increasing their proliferation and glucose-stimulated insulin secretion. In this review we examine how placental and maternal hormones work cooperatively to activate several signalling pathways, transcription factors and epigenetic regulators to drive adaptations in β-cell function during pregnancy. We also explore how adverse maternal environmental conditions, including malnutrition, obesity, circadian rhythm disruption and environmental pollutants, may impact the endocrine and molecular mechanisms controlling β-cell adaptations during pregnancy. The available data from human and experimental animal studies highlight the need to better understand how maternal β-cells integrate the various environmental, metabolic and endocrine cues and thereby determine appropriate β-cell adaptation during gestation. In doing so, these studies may identify targetable pathways that could be used to prevent not only the development of pregnancy complications like gestational diabetes that impact maternal and fetal wellbeing, but also more generally the pathogenesis of other metabolic conditions like type 2 diabetes.
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Affiliation(s)
- Esteban Roberto Salazar-Petres
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Amanda Nancy Sferruzzi-Perri
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
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Ibos KE, Bodnár É, Bagosi Z, Bozsó Z, Tóth G, Szabó G, Csabafi K. Kisspeptin-8 Induces Anxiety-Like Behavior and Hypolocomotion by Activating the HPA Axis and Increasing GABA Release in the Nucleus Accumbens in Rats. Biomedicines 2021; 9:112. [PMID: 33503835 PMCID: PMC7911394 DOI: 10.3390/biomedicines9020112] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/18/2021] [Accepted: 01/22/2021] [Indexed: 12/11/2022] Open
Abstract
Kisspeptins (Kp) are RF-amide neuropeptide regulators of the reproductive axis that also influence anxiety, locomotion, and metabolism. We aimed to investigate the effects of intracerebroventricular Kp-8 (an N-terminally truncated octapeptide) treatment in Wistar rats. Elevated plus maze (EPM), computerized open field (OF), and marble burying (MB) tests were performed for the assessment of behavior. Serum LH and corticosterone levels were determined to assess kisspeptin1 receptor (Kiss1r) activation and hypothalamic-pituitary-adrenal axis (HPA) stimulation, respectively. GABA release from the nucleus accumbens (NAc) and dopamine release from the ventral tegmental area (VTA) and NAc were measured via ex vivo superfusion. Kp-8 decreased open arm time and entries in EPM, and also raised corticosterone concentration, pointing to an anxiogenic effect. Moreover, the decrease in arm entries in EPM, the delayed increase in immobility accompanied by reduced ambulatory activity in OF, and the reduction in interactions with marbles show that Kp-8 suppressed exploratory and spontaneous locomotion. The increase in GABA release from the NAc might be in the background of hypolocomotion by inhibiting the VTA-NAc dopaminergic circuitry. As Kp-8 raised LH concentration, it could activate Kiss1r and stimulate the reproductive axis. As Kiss1r is associated with hyperlocomotion, it is more likely that neuropeptide FF receptor activation is involved in the suppression of locomotor activity.
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Affiliation(s)
- Katalin Eszter Ibos
- Department of Pathophysiology, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (É.B.); (Z.B.); (K.C.)
| | - Éva Bodnár
- Department of Pathophysiology, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (É.B.); (Z.B.); (K.C.)
| | - Zsolt Bagosi
- Department of Pathophysiology, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (É.B.); (Z.B.); (K.C.)
| | - Zsolt Bozsó
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (Z.B.); (G.T.)
| | - Gábor Tóth
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (Z.B.); (G.T.)
| | - Gyula Szabó
- Office of International Affairs, Budapest Campus, McDaniel College, H-1071 Budapest, Hungary;
| | - Krisztina Csabafi
- Department of Pathophysiology, Faculty of Medicine, University of Szeged, H-6720 Szeged, Hungary; (É.B.); (Z.B.); (K.C.)
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Andersson CR, Selvin T, Blom K, Rubin J, Berglund M, Jarvius M, Lenhammar L, Parrow V, Loskog A, Fryknäs M, Nygren P, Larsson R. Mebendazole is unique among tubulin-active drugs in activating the MEK-ERK pathway. Sci Rep 2020; 10:13124. [PMID: 32753665 PMCID: PMC7403428 DOI: 10.1038/s41598-020-68986-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/19/2020] [Indexed: 11/09/2022] Open
Abstract
We recently showed that the anti-helminthic compound mebendazole (MBZ) has immunomodulating activity in monocyte/macrophage models and induces ERK signalling. In the present study we investigated whether MBZ induced ERK activation is shared by other tubulin binding agents (TBAs) and if it is observable also in other human cell types. Curated gene signatures for a panel of TBAs in the LINCS Connectivity Map (CMap) database showed a unique strong negative correlation of MBZ with MEK/ERK inhibitors indicating ERK activation also in non-haematological cell lines. L1000 gene expression signatures for MBZ treated THP-1 monocytes also connected negatively to MEK inhibitors. MEK/ERK phosphoprotein activity testing of a number of TBAs showed that only MBZ increased the activity in both THP-1 monocytes and PMA differentiated macrophages. Distal effects on ERK phosphorylation of the substrate P90RSK and release of IL1B followed the same pattern. The effect of MBZ on MEK/ERK phosphorylation was inhibited by RAF/MEK/ERK inhibitors in THP-1 models, CD3/IL2 stimulated PBMCs and a MAPK reporter HEK-293 cell line. MBZ was also shown to increase ERK activity in CD4+ T-cells from lupus patients with known defective ERK signalling. Given these mechanistic features MBZ is suggested suitable for treatment of diseases characterized by defective ERK signalling, notably difficult to treat autoimmune diseases.
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Affiliation(s)
- Claes R Andersson
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden.
| | - Tove Selvin
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Kristin Blom
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Jenny Rubin
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Malin Berglund
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Malin Jarvius
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Lena Lenhammar
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Vendela Parrow
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Angelica Loskog
- Department of Immunology, Genetics and Pathology, Section of Oncology, Uppsala University, 75185, Uppsala, Sweden
| | - Mårten Fryknäs
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Peter Nygren
- Department of Immunology, Genetics and Pathology, Section of Oncology, Uppsala University, 75185, Uppsala, Sweden
| | - Rolf Larsson
- Division of Cancer Pharmacology and Computational Medicine, Department of Medical Sciences, Uppsala University, 75185, Uppsala, Sweden.
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Toubal S, Oiry C, Bayle M, Cros G, Neasta J. Urolithin C increases glucose-induced ERK activation which contributes to insulin secretion. Fundam Clin Pharmacol 2020; 34:571-580. [PMID: 32083757 DOI: 10.1111/fcp.12551] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/14/2020] [Accepted: 02/20/2020] [Indexed: 12/31/2022]
Abstract
Polyphenols exert pharmacological actions through protein-mediated mechanisms and by modulating intracellular signalling pathways. We recently showed that a gut-microbial metabolite of ellagic acid named urolithin C is a glucose-dependent activator of insulin secretion acting by facilitating L-type Ca2+ channel opening and Ca2+ influx into pancreatic β-cells. However, it is still unknown whether urolithin C regulates key intracellular signalling proteins in β-cells. Here, we report that urolithin C enhanced glucose-induced extracellular signal-regulated kinases 1/2 (ERK1/2) activation as shown by higher phosphorylation levels in INS-1 β-cells. Interestingly, inhibition of ERK1/2 with two structurally distinct inhibitors led to a reduction in urolithin C effect on insulin secretion. Finally, we provide data to suggest that urolithin C-mediated ERK1/2 phosphorylation involved insulin signalling in INS-1 cells. Together, these data indicate that the pharmacological action of urolithin C on insulin secretion relies, in part, on its capacity to enhance glucose-induced ERK1/2 activation. Therefore, our study extends our understanding of the pharmacological action of urolithin C in β-cells. More generally, our findings revealed that urolithin C modulated the activation of key multifunctional intracellular signalling kinases which participate in the regulation of numerous biological processes.
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Affiliation(s)
- Slimane Toubal
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | - Catherine Oiry
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | - Morgane Bayle
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | - Gérard Cros
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | - Jérémie Neasta
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
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8
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Bowe JE, Hill TG, Hunt KF, Smith LI, Simpson SJ, Amiel SA, Jones PM. A role for placental kisspeptin in β cell adaptation to pregnancy. JCI Insight 2019; 4:124540. [PMID: 31619585 PMCID: PMC6824306 DOI: 10.1172/jci.insight.124540] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 09/11/2019] [Indexed: 12/19/2022] Open
Abstract
During pregnancy the maternal pancreatic islets of Langerhans undergo adaptive changes to compensate for gestational insulin resistance. Kisspeptin has been shown to stimulate insulin release, through its receptor, GPR54. The placenta releases high levels of kisspeptin into the maternal circulation, suggesting a role in modulating the islet adaptation to pregnancy. In the present study we show that pharmacological blockade of endogenous kisspeptin in pregnant mice resulted in impaired glucose homeostasis. This glucose intolerance was due to a reduced insulin response to glucose as opposed to any effect on insulin sensitivity. A β cell–specific GPR54-knockdown mouse line was found to exhibit glucose intolerance during pregnancy, with no phenotype observed outside of pregnancy. Furthermore, in pregnant women circulating kisspeptin levels significantly correlated with insulin responses to oral glucose challenge and were significantly lower in women with gestational diabetes (GDM) compared with those without GDM. Thus, kisspeptin represents a placental signal that plays a physiological role in the islet adaptation to pregnancy, maintaining maternal glucose homeostasis by acting through the β cell GPR54 receptor. Our data suggest reduced placental kisspeptin production, with consequent impaired kisspeptin-dependent β cell compensation, may be a factor in the development of GDM in humans. Placental kisspeptin regulates islet adaptation to pregnancy that is necessary for preventing gestational diabetes in mice and humans.
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Olaniru OE, Pingitore A, Giera S, Piao X, Castañera González R, Jones PM, Persaud SJ. The adhesion receptor GPR56 is activated by extracellular matrix collagen III to improve β-cell function. Cell Mol Life Sci 2018; 75:4007-4019. [PMID: 29855662 PMCID: PMC6182347 DOI: 10.1007/s00018-018-2846-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/11/2018] [Accepted: 05/24/2018] [Indexed: 12/19/2022]
Abstract
AIMS G-protein coupled receptor 56 (GPR56) is the most abundant islet-expressed G-protein coupled receptor, suggesting a potential role in islet function. This study evaluated islet expression of GPR56 and its endogenous ligand collagen III, and their effects on β-cell function. METHODS GPR56 and collagen III expression in mouse and human pancreas sections was determined by fluorescence immunohistochemistry. Effects of collagen III on β-cell proliferation, apoptosis, intracellular calcium ([Ca2+]i) and insulin secretion were determined by cellular BrdU incorporation, caspase 3/7 activities, microfluorimetry and radioimmunoassay, respectively. The role of GPR56 in islet vascularisation and innervation was evaluated by immunohistochemical staining for CD31 and TUJ1, respectively, in pancreases from wildtype (WT) and Gpr56-/- mice, and the requirement of GPR56 for normal glucose homeostasis was determined by glucose tolerance tests in WT and Gpr56-/- mice. RESULTS Immunostaining of mouse and human pancreases revealed that GPR56 was expressed by islet β-cells while collagen III was confined to the peri-islet basement membrane and islet capillaries. Collagen III protected β-cells from cytokine-induced apoptosis, triggered increases in [Ca2+]i and potentiated glucose-induced insulin secretion from WT islets but not from Gpr56-/- islets. Deletion of GPR56 did not affect glucose-induced insulin secretion in vitro and it did not impair glucose tolerance in adult mice. GPR56 was not required for normal islet vascularisation or innervation. CONCLUSION We have demonstrated that collagen III improves islet function by increasing insulin secretion and protecting against apoptosis. Our data suggest that collagen III may be effective in optimising islet function to improve islet transplantation outcomes, and GPR56 may be a target for the treatment of type 2 diabetes.
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Affiliation(s)
- Oladapo E Olaniru
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Attilio Pingitore
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Stefanie Giera
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Xianhua Piao
- Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Ramón Castañera González
- Department of General Surgery, Rio Carrión Hospital, University Hospital Complex of Palencia, Palencia, Spain
| | - Peter M Jones
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Shanta J Persaud
- Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London, SE1 1UL, UK.
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10
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Leduc M, Richard J, Costes S, Muller D, Varrault A, Compan V, Mathieu J, Tanti JF, Pagès G, Pouyssegur J, Bertrand G, Dalle S, Ravier MA. ERK1 is dispensable for mouse pancreatic beta cell function but is necessary for glucose-induced full activation of MSK1 and CREB. Diabetologia 2017; 60:1999-2010. [PMID: 28721437 DOI: 10.1007/s00125-017-4356-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 06/02/2017] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Insufficient insulin secretion from pancreatic beta cells, which is associated with a decrease in beta cell mass, is a characteristic of type 2 diabetes. Extracellular signal-related kinase 1 and 2 (ERK1/2) inhibition in beta cells has been reported to affect insulin secretion, gene transcription and survival, although whether ERK1 and ERK2 play distinct roles is unknown. The aim of this study was to assess the individual roles of ERK1 and ERK2 in beta cells using ERK1 (also known as Mapk3)-knockout mice (Erk1 -/- mice) and pharmacological approaches. METHODS NAD(P)H, free cytosolic Ca2+ concentration and insulin secretion were determined in islets. ERK1 and ERK2 subplasmalemmal translocation and activity was monitored using total internal reflection fluorescence microscopy. ERK1/2, mitogen and stress-activated kinase1 (MSK1) and cAMP-responsive element-binding protein (CREB) activation were evaluated by western blot and/or immunocytochemistry. The islet mass was determined from pancreatic sections. RESULTS Glucose induced rapid subplasmalemmal recruitment of ERK1 and ERK2. When both ERK1 and ERK2 were inhibited simultaneously, the rapid transient peak of the first phase of glucose-induced insulin secretion was reduced by 40% (p < 0.01), although ERK1 did not appear to be involved in this process. By contrast, ERK1 was required for glucose-induced full activation of several targets involved in beta cell survival; MSK1 and CREB were less active in Erk1 -/- mouse beta cells (p < 0.01) compared with Erk1 +/+ mouse beta cells, and their phosphorylation could only be restored when ERK1 was re-expressed and not when ERK2 was overexpressed. Finally, the islet mass of Erk1 -/- mice was slightly increased in young animals (4-month-old mice) vs Erk1 +/+ mice (section occupied by islets [mean ± SEM]: 0.74% ± 0.03% vs 0.62% ± 0.04%; p < 0.05), while older mice (10 months old) were less prone to age-associated pancreatic peri-insulitis (infiltrated islets [mean ± SEM]: 7.51% ± 1.34% vs 2.03% ± 0.51%; p < 0.001). CONCLUSIONS/INTERPRETATION ERK1 and ERK2 play specific roles in beta cells. ERK2 cannot always compensate for the lack of ERK1 but the absence of a clear-cut phenotype in Erk1 -/- mice shows that ERK1 is dispensable in normal conditions.
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Affiliation(s)
- Michele Leduc
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Joy Richard
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Safia Costes
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Dany Muller
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Annie Varrault
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Vincent Compan
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Julia Mathieu
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Jean-François Tanti
- Faculté de Médecine, Centre Méditerranéen de Médecine Moléculaire, Inserm U1065, Université de Nice Sophia Antipolis, Nice, France
| | - Gilles Pagès
- Institute for Research on Cancer and Aging, Nice (IRCAN), Centre Antoine Lacassagne, Université de Nice Sophia Antipolis, Nice, France
| | - Jacques Pouyssegur
- Institute for Research on Cancer and Aging, Nice (IRCAN), Centre Antoine Lacassagne, Université de Nice Sophia Antipolis, Nice, France
- Medical Biology Department, Centre Scientifique de Monaco (CSM), Monaco, Principality of Monaco
| | - Gyslaine Bertrand
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Stéphane Dalle
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France
| | - Magalie A Ravier
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Montpellier, 141 Rue de la Cardonille, 34094, Montpellier CEDEX 5, France.
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Warren JL, Hoxha E, Jumbo-Lucioni P, De Luca M. Reduction of Syndecan Transcript Levels in the Insulin-Producing Cells Affects Glucose Homeostasis in Adult Drosophila melanogaster. DNA Cell Biol 2017; 36:959-965. [PMID: 28945109 DOI: 10.1089/dna.2017.3912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Signaling by direct cell-matrix interactions has been shown to impact the transcription, secretion, and storage of insulin in mammalian β cells. However, more research is still needed in this area. Syndecans are transmembrane heparan sulfate proteoglycans that function independently and in synergy with integrin-mediated signaling to mediate cell adhesion to the extracellular matrix. In this study, we used the model organism Drosophila melanogaster to determine whether knockdown of the Syndecan (Sdc) gene expression specifically in the insulin-producing cells (IPCs) might affect insulin-like peptide (ILP) production and secretion. IPCs of adult flies produce three ILPs (ILP2, ILP3, and ILP5), which have significant homology to mammalian insulin. We report that flies with reduced Sdc expression in the IPCs did not show any difference in the expression of ilp genes compared to controls. However, they had significantly reduced levels of the circulating ILP2 protein, higher circulating carbohydrates, and were less glucose tolerant than control flies. Finally, we found that IPCs-specific Sdc knockdown led to reduced levels of head Glucose transporter1 gene expression, extracellular signal-regulated kinase phosphorylation, and reactive oxygen species. Taken together, our findings suggest a cell autonomous role for Sdc in insulin release in D. melanogaster.
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Affiliation(s)
- Jonathan L Warren
- 1 Department of Nutrition Sciences, University of Alabama at Birmingham , Birmingham, Alabama
| | - Eneida Hoxha
- 1 Department of Nutrition Sciences, University of Alabama at Birmingham , Birmingham, Alabama.,2 Department of Biology, Ecology and Earth Science, University of Calabria , Rende, Italy
| | - Patricia Jumbo-Lucioni
- 1 Department of Nutrition Sciences, University of Alabama at Birmingham , Birmingham, Alabama.,3 Department of Pharmaceutical, Social and Administrative Sciences, McWhorter School of Pharmacy, Samford University , Birmingham, Alabama
| | - Maria De Luca
- 1 Department of Nutrition Sciences, University of Alabama at Birmingham , Birmingham, Alabama
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Arous C, Wehrle-Haller B. Role and impact of the extracellular matrix on integrin-mediated pancreatic β-cell functions. Biol Cell 2017; 109:223-237. [PMID: 28266044 DOI: 10.1111/boc.201600076] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 12/17/2022]
Abstract
Understanding the organisation and role of the extracellular matrix (ECM) in islets of Langerhans is critical for maintaining pancreatic β-cells, and to recognise and revert the physiopathology of diabetes. Indeed, integrin-mediated adhesion signalling in response to the pancreatic ECM plays crucial roles in β-cell survival and insulin secretion, two major functions, which are affected in diabetes. Here, we would like to present an update on the major components of the pancreatic ECM, their role during integrin-mediated cell-matrix adhesions and how they are affected during diabetes. To treat diabetes, a promising approach consists in replacing β-cells by transplantation. However, efficiency is low, because β-cells suffer of anoikis, due to enzymatic digestion of the pancreatic ECM, which affects the survival of insulin-secreting β-cells. The strategy of adding ECM components during transplantation, to reproduce the pancreatic microenvironment, is a challenging task, as many of the regulatory mechanisms that control ECM deposition and turnover are not sufficiently understood. A better comprehension of the impact of the ECM on the adhesion and integrin-dependent signalling in β-cells is primordial to improve the healthy state of islets to prevent the onset of diabetes as well as for enhancing the efficiency of the islet transplantation therapy.
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Affiliation(s)
- Caroline Arous
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center, Geneva, Switzerland
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center, Geneva, Switzerland
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Quinault A, Gausseres B, Bailbe D, Chebbah N, Portha B, Movassat J, Tourrel-Cuzin C. Disrupted dynamics of F-actin and insulin granule fusion in INS-1 832/13 beta-cells exposed to glucotoxicity: partial restoration by glucagon-like peptide 1. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1401-11. [DOI: 10.1016/j.bbadis.2016.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/22/2016] [Accepted: 04/11/2016] [Indexed: 01/11/2023]
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14
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Arous C, Halban PA. The skeleton in the closet: actin cytoskeletal remodeling in β-cell function. Am J Physiol Endocrinol Metab 2015; 309:E611-20. [PMID: 26286869 DOI: 10.1152/ajpendo.00268.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/11/2015] [Indexed: 01/13/2023]
Abstract
Over the last few decades, biomedical research has considered not only the function of single cells but also the importance of the physical environment within a whole tissue, including cell-cell and cell-extracellular matrix interactions. Cytoskeleton organization and focal adhesions are crucial sensors for cells that enable them to rapidly communicate with the physical extracellular environment in response to extracellular stimuli, ensuring proper function and adaptation. The involvement of the microtubular-microfilamentous cytoskeleton in secretion mechanisms was proposed almost 50 years ago, since when the evolution of ever more sensitive and sophisticated methods in microscopy and in cell and molecular biology have led us to become aware of the importance of cytoskeleton remodeling for cell shape regulation and its crucial link with signaling pathways leading to β-cell function. Emerging evidence suggests that dysfunction of cytoskeletal components or extracellular matrix modification influences a number of disorders through potential actin cytoskeleton disruption that could be involved in the initiation of multiple cellular functions. Perturbation of β-cell actin cytoskeleton remodeling could arise secondarily to islet inflammation and fibrosis, possibly accounting in part for impaired β-cell function in type 2 diabetes. This review focuses on the role of actin remodeling in insulin secretion mechanisms and its close relationship with focal adhesions and myosin II.
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Affiliation(s)
- Caroline Arous
- Department of Genetic Medicine and Development, University of Geneva Medical Center, Geneva, Switzerland
| | - Philippe A Halban
- Department of Genetic Medicine and Development, University of Geneva Medical Center, Geneva, Switzerland
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Wei H, Ning LP, Zhang Y, Yue SW. Role of actin filaments in allodynia induced by chronic compression of the dorsal root ganglion. Neurosci Lett 2015; 600:38-44. [DOI: 10.1016/j.neulet.2015.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/13/2015] [Accepted: 05/06/2015] [Indexed: 12/15/2022]
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16
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Ferreira SM, Santos GJ, Rezende LF, Gonçalves LM, Santos-Silva JC, Bigarella CL, Carneiro EM, Saad STO, Boschero AC, Barbosa-Sampaio HC. ARHGAP21 prevents abnormal insulin release through actin rearrangement in pancreatic islets from neonatal mice. Life Sci 2015; 127:53-8. [PMID: 25744409 DOI: 10.1016/j.lfs.2015.01.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 01/06/2015] [Accepted: 01/26/2015] [Indexed: 12/31/2022]
Abstract
AIMS ARHGAP21 is a Rho GTPase-activating protein (RhoGAP) that associates with many proteins and modulates several cellular functions, including actin cytoskeleton rearrangement in different tissues. However, it is unknown whether ARHGAP21 is expressed in pancreatic beta cells and its function in these cells. Herein, we assess the participation of ARHGAP21 in insulin secretion. MAIN METHODS Neonatal mice were treated with anti-sense oligonucleotide against ARHG AP21 (AS) for 2 days, resulting in a reduction of the protein's expression of about 60% in the islets. F-actin depolimerization, insulin secretion,mRNA level of genes involved in insulin secretion, maturation and proliferation were evaluated in islets from both control and AS-treated mice. KEY FINDINGS ARHGAP21 co-localized with actin inMIN6 beta cells and with insulin in neonatal pancreatic islets. F-actin was reduced in AS-islets, as judged by lower phalloidin intensity. Insulin secretion was increased in islets from AS-treated mice, however no differences were observed in the GSIS (glucose-stimulated insulin secretion). In these islets, the pERK1/2 was increased, as well as the gene expressions of VAMP2 and SNAP25, proteins that are present in the secretory machinery. Maturation and cell proliferation were not affected in islets from AS-treated mice. SIGNIFICANCE In conclusion, our data show, for the first time, that ARHGAP21 is expressed and participates in the secretory process of pancreatic beta cells. Its effect is probably via pERK1/2, which modulates the rearrangement of the cytoskeleton. ARHGAP21 also controls the expression of genes that encodes proteins of the secretory machinery.
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Affiliation(s)
- Sandra Mara Ferreira
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Gustavo Jorge Santos
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Luiz F Rezende
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Luciana Mateus Gonçalves
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Junia Carolina Santos-Silva
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Carolina Louzão Bigarella
- Department of Internal Medicine, School of Medical Science, Hematology and Hemotherapy Center - Hemocentro, INCT Sangue, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Everardo Magalhães Carneiro
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Sara Teresinha Ollala Saad
- Department of Internal Medicine, School of Medical Science, Hematology and Hemotherapy Center - Hemocentro, INCT Sangue, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Antonio Carlos Boschero
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Helena Cristina Barbosa-Sampaio
- Department of Structural and Functional Biology, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Signaling mechanisms of glucose-induced F-actin remodeling in pancreatic islet β cells. Exp Mol Med 2013; 45:e37. [PMID: 23969997 PMCID: PMC3789261 DOI: 10.1038/emm.2013.73] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 06/24/2013] [Indexed: 12/12/2022] Open
Abstract
The maintenance of whole-body glucose homeostasis is critical for survival, and is controlled by the coordination of multiple organs and endocrine systems. Pancreatic islet β cells secrete insulin in response to nutrient stimuli, and insulin then travels through the circulation promoting glucose uptake into insulin-responsive tissues such as liver, skeletal muscle and adipose. Many of the genes identified in human genome-wide association studies of diabetic individuals are directly associated with β cell survival and function, giving credence to the idea that β-cell dysfunction is central to the development of type 2 diabetes. As such, investigations into the mechanisms by which β cells sense glucose and secrete insulin in a regulated manner are a major focus of current diabetes research. In particular, recent discoveries of the detailed role and requirements for reorganization/remodeling of filamentous actin (F-actin) in the regulation of insulin release from the β cell have appeared at the forefront of islet function research, having lapsed in prior years due to technical limitations. Recent advances in live-cell imaging and specialized reagents have revealed localized F-actin remodeling to be a requisite for the normal biphasic pattern of nutrient-stimulated insulin secretion. This review will provide an historical look at the emergent focus on the role of the actin cytoskeleton and its regulation of insulin secretion, leading up to the cutting-edge research in progress in the field today.
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Wauson EM, Guerra ML, Barylko B, Albanesi JP, Cobb MH. Off-target effects of MEK inhibitors. Biochemistry 2013; 52:5164-6. [PMID: 23848362 DOI: 10.1021/bi4007644] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mitogen-activated protein kinases (MAPKs) ERK1/2 regulate numerous cellular processes, including gene transcription, proliferation, and differentiation. The only known substrates of the MAP2Ks MEK1/2 are ERK1/2; thus, MEK inhibitors PD98059, U0126, and PD0325901 have been important tools in determining the functions of ERK1/2. By using these inhibitors and genetically manipulating MEK, we found that ERK1/2 activation is neither sufficient nor necessary for regulated secretion of insulin from pancreatic β cells or secretion of epinephrine from chromaffin cells. We show that both PD98059 and U0126 reduce agonist-induced entry of calcium into cells in a manner independent of their ability to inhibit ERK1/2. Caution should be used when interpreting results from experiments using these compounds.
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Affiliation(s)
- Eric M Wauson
- Department of Pharmacology, University of Texas Southwestern Medical Center , Dallas, Texas 75390-9041, United States
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