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Rivera Nieves AM, Wauford BM, Fu A. Mitochondrial bioenergetics, metabolism, and beyond in pancreatic β-cells and diabetes. Front Mol Biosci 2024; 11:1354199. [PMID: 38404962 PMCID: PMC10884328 DOI: 10.3389/fmolb.2024.1354199] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/17/2024] [Indexed: 02/27/2024] Open
Abstract
In Type 1 and Type 2 diabetes, pancreatic β-cell survival and function are impaired. Additional etiologies of diabetes include dysfunction in insulin-sensing hepatic, muscle, and adipose tissues as well as immune cells. An important determinant of metabolic health across these various tissues is mitochondria function and structure. This review focuses on the role of mitochondria in diabetes pathogenesis, with a specific emphasis on pancreatic β-cells. These dynamic organelles are obligate for β-cell survival, function, replication, insulin production, and control over insulin release. Therefore, it is not surprising that mitochondria are severely defective in diabetic contexts. Mitochondrial dysfunction poses challenges to assess in cause-effect studies, prompting us to assemble and deliberate the evidence for mitochondria dysfunction as a cause or consequence of diabetes. Understanding the precise molecular mechanisms underlying mitochondrial dysfunction in diabetes and identifying therapeutic strategies to restore mitochondrial homeostasis and enhance β-cell function are active and expanding areas of research. In summary, this review examines the multidimensional role of mitochondria in diabetes, focusing on pancreatic β-cells and highlighting the significance of mitochondrial metabolism, bioenergetics, calcium, dynamics, and mitophagy in the pathophysiology of diabetes. We describe the effects of diabetes-related gluco/lipotoxic, oxidative and inflammation stress on β-cell mitochondria, as well as the role played by mitochondria on the pathologic outcomes of these stress paradigms. By examining these aspects, we provide updated insights and highlight areas where further research is required for a deeper molecular understanding of the role of mitochondria in β-cells and diabetes.
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Affiliation(s)
- Alejandra María Rivera Nieves
- Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Brian Michael Wauford
- Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
| | - Accalia Fu
- Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, United States
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, United States
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Cao R, Tian H, Zhang Y, Liu G, Xu H, Rao G, Tian Y, Fu X. Signaling pathways and intervention for therapy of type 2 diabetes mellitus. MedComm (Beijing) 2023; 4:e283. [PMID: 37303813 PMCID: PMC10248034 DOI: 10.1002/mco2.283] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/18/2023] [Accepted: 04/27/2023] [Indexed: 06/13/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) represents one of the fastest growing epidemic metabolic disorders worldwide and is a strong contributor for a broad range of comorbidities, including vascular, visual, neurological, kidney, and liver diseases. Moreover, recent data suggest a mutual interplay between T2DM and Corona Virus Disease 2019 (COVID-19). T2DM is characterized by insulin resistance (IR) and pancreatic β cell dysfunction. Pioneering discoveries throughout the past few decades have established notable links between signaling pathways and T2DM pathogenesis and therapy. Importantly, a number of signaling pathways substantially control the advancement of core pathological changes in T2DM, including IR and β cell dysfunction, as well as additional pathogenic disturbances. Accordingly, an improved understanding of these signaling pathways sheds light on tractable targets and strategies for developing and repurposing critical therapies to treat T2DM and its complications. In this review, we provide a brief overview of the history of T2DM and signaling pathways, and offer a systematic update on the role and mechanism of key signaling pathways underlying the onset, development, and progression of T2DM. In this content, we also summarize current therapeutic drugs/agents associated with signaling pathways for the treatment of T2DM and its complications, and discuss some implications and directions to the future of this field.
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Affiliation(s)
- Rong Cao
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Huimin Tian
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yu Zhang
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Geng Liu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Haixia Xu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Guocheng Rao
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yan Tian
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Xianghui Fu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
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Evans AM. Of Mice and Men and Plethysmography Systems: Does LKB1 Determine the Set Point of Carotid Body Chemosensitivity and the Hypoxic Ventilatory Response? Adv Exp Med Biol 2023; 1427:163-173. [PMID: 37322347 DOI: 10.1007/978-3-031-32371-3_18] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Our recent studies suggest that the level of liver kinase B1 (LKB1) expression in some way determines carotid body afferent discharge during hypoxia and to a lesser extent during hypercapnia. In short, phosphorylation by LKB1 of an as yet unidentified target(s) determines a set point for carotid body chemosensitivity. LKB1 is the principal kinase that activates the AMP-activated protein kinase (AMPK) during metabolic stresses, but conditional deletion of AMPK in catecholaminergic cells, including therein carotid body type I cells, has little or no effect on carotid body responses to hypoxia or hypercapnia. With AMPK excluded, the most likely target of LKB1 is one or other of the 12 AMPK-related kinases, which are constitutively phosphorylated by LKB1 and, in general, regulate gene expression. By contrast, the hypoxic ventilatory response is attenuated by either LKB1 or AMPK deletion in catecholaminergic cells, precipitating hypoventilation and apnea during hypoxia rather than hyperventilation. Moreover, LKB1, but not AMPK, deficiency causes Cheyne-Stokes-like breathing. This chapter will explore further the possible mechanisms that determine these outcomes.
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Affiliation(s)
- A Mark Evans
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh, UK.
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MacMillan S, Holmes AP, Dallas ML, Mahmoud AD, Shipston MJ, Peers C, Hardie DG, Kumar P, Evans AM. LKB1 is the gatekeeper of carotid body chemosensing and the hypoxic ventilatory response. Commun Biol 2022; 5:642. [PMID: 35768580 DOI: 10.1038/s42003-022-03583-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 06/14/2022] [Indexed: 11/08/2022] Open
Abstract
The hypoxic ventilatory response (HVR) is critical to breathing and thus oxygen supply to the body and is primarily mediated by the carotid bodies. Here we reveal that carotid body afferent discharge during hypoxia and hypercapnia is determined by the expression of Liver Kinase B1 (LKB1), the principal kinase that activates the AMP-activated protein kinase (AMPK) during metabolic stresses. Conversely, conditional deletion in catecholaminergic cells of AMPK had no effect on carotid body responses to hypoxia or hypercapnia. By contrast, the HVR was attenuated by LKB1 and AMPK deletion. However, in LKB1 knockouts hypoxia evoked hypoventilation, apnoea and Cheyne-Stokes-like breathing, while only hypoventilation and apnoea were observed after AMPK deletion. We therefore identify LKB1 as an essential regulator of carotid body chemosensing and uncover a divergence in dependency on LKB1 and AMPK between the carotid body on one hand and the HVR on the other.
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Nguyen-Tu MS, Harris J, Martinez-Sanchez A, Chabosseau P, Hu M, Georgiadou E, Pollard A, Otero P, Lopez-Noriega L, Leclerc I, Sakamoto K, Schmoll D, Smith DM, Carling D, Rutter GA. Opposing effects on regulated insulin secretion of acute vs chronic stimulation of AMP-activated protein kinase. Diabetologia 2022; 65:997-1011. [PMID: 35294578 PMCID: PMC9076735 DOI: 10.1007/s00125-022-05673-x] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 12/13/2021] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Although targeted in extrapancreatic tissues by several drugs used to treat type 2 diabetes, the role of AMP-activated protein kinase (AMPK) in the control of insulin secretion is still debatable. Previous studies have used pharmacological activators of limited selectivity and specificity, and none has examined in primary pancreatic beta cells the actions of the latest generation of highly potent and specific activators that act via the allosteric drug and metabolite (ADaM) site. METHODS AMPK was activated acutely in islets isolated from C57BL6/J mice, and in an EndoC-βH3 cell line, using three structurally distinct ADaM site activators (991, PF-06409577 and RA089), with varying selectivity for β1- vs β2-containing complexes. Mouse lines expressing a gain-of-function mutation in the γ1 AMPK subunit (D316a) were generated to examine the effects of chronic AMPK stimulation in the whole body, or selectively in the beta cell. RESULTS Acute (1.5 h) treatment of wild-type mouse islets with 991, PF-06409577 or RA089 robustly stimulated insulin secretion at high glucose concentrations (p<0.01, p<0.05 and p<0.001, respectively), despite a lowering of glucose-induced intracellular free Ca2+ dynamics in response to 991 (AUC, p<0.05) and to RA089 at the highest dose (25 μmol/l) at 5.59 min (p<0.05). Although abolished in the absence of AMPK, the effects of 991 were observed in the absence of the upstream kinase, liver kinase B1, further implicating 'amplifying' pathways. In marked contrast, chronic activation of AMPK, either globally or selectively in the beta cell, achieved using a gain-of-function mutant, impaired insulin release in vivo (p<0.05 at 15 min following i.p. injection of 3 mmol/l glucose) and in vitro (p<0.01 following incubation of islets with 17 mmol/l glucose), and lowered glucose tolerance (p<0.001). CONCLUSIONS/INTERPRETATION AMPK activation exerts complex, time-dependent effects on insulin secretion. These observations should inform the design and future clinical use of AMPK modulators.
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Affiliation(s)
- Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Joseph Harris
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Ming Hu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Eleni Georgiadou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Alice Pollard
- MRC- London Institute of Medical Sciences, Imperial College London, London, UK
- Structure Biophysics and Fragments, Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | - Pablo Otero
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Livia Lopez-Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Kei Sakamoto
- Novo Nordisk Center for Basic Metabolic Research, Copenhagen, Denmark
| | - Dieter Schmoll
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - David M Smith
- Emerging Innovations Unit, Discovery Sciences, AstraZeneca R&D , Cambridge, UK
| | - David Carling
- MRC- London Institute of Medical Sciences, Imperial College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Republic of Singapore.
- CR-CHUM, University of Montréal, Montréal, QC, Canada.
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Lei L, Huan Y, Liu Q, Li C, Cao H, Ji W, Gao X, Fu Y, Li P, Zhang R, Abliz Z, Liu Y, Liu S, Shen Z. Morus alba L. (Sangzhi) Alkaloids Promote Insulin Secretion, Restore Diabetic β-Cell Function by Preventing Dedifferentiation and Apoptosis. Front Pharmacol 2022; 13:841981. [PMID: 35308210 PMCID: PMC8927674 DOI: 10.3389/fphar.2022.841981] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/14/2022] [Indexed: 11/25/2022] Open
Abstract
Background:Morus alba L. (Sangzhi) alkaloids (SZ-A), extracted from the Chinese herb Morus alba L. (mulberry twig), have been shown to ameliorate hyperglycemia in type 2 diabetes and have been approved for diabetes treatment in the clinic. However, their versatile pharmacologic effects and regulatory mechanisms are not yet completely understood. Purpose: This study explored the protective effects of SZ-A on islet β cells and the underlying mechanism. Methods: Type 2 diabetic KKAy mice were orally administered SZ-A (100 or 200 mg/kg, once daily) for 11 weeks, and oral glucose tolerance, insulin tolerance, intraperitoneal glucose tolerance and hyperglycemia clamp tests were carried out to evaluate the potency of SZ-A in vivo. The morphology and β-cell dedifferentiation marker of KKAy mouse islets were detected via immunofluorescence. The effect of SZ-A on glucose-stimulated insulin secretion was investigated in both the islet β-cell line MIN6 and mouse primary islets. Potential regulatory signals and pathways in insulin secretion were explored, and cell proliferation assays and apoptosis TUNEL staining were performed on SZ-A-treated MIN6 cells. Results: SZ-A alleviated hyperglycemia and glucose intolerance in type 2 diabetic KKAy mice and improved the function and morphology of diabetic islets. In both MIN6 cells and primary islets, SZ-A promoted insulin secretion. At a normal glucose level, SZ-A decreased AMPKα phosphorylation, and at high glucose, SZ-A augmented the cytosolic calcium concentration. Additionally, SZ-A downregulated the β-cell dedifferentiation marker ALDH1A3 and upregulated β-cell identifying genes, such as Ins1, Ins2, Nkx2.2 and Pax4 in KKAy mice islets. At the same time, SZ-A attenuated glucolipotoxicity-induced apoptosis in MIN6 cells, and inhibited Erk1/2 phosphorylation and caspase 3 activity. The major active fractions of SZ-A, namely DNJ, FAG and DAB, participated in the above regulatory effects. Conclusion: Our findings suggest that SZ-A promotes insulin secretion in islet β cells and ameliorates β-cell dysfunction and mass reduction under diabetic conditions both in vivo and in vitro, providing additional supportive evidence for the clinical application of SZ-A.
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Affiliation(s)
- Lei Lei
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yi Huan
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Yi Huan, ; Shuainan Liu,
| | - Quan Liu
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Caina Li
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui Cao
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wenming Ji
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuefeng Gao
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yaxin Fu
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Pingping Li
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ruiping Zhang
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zeper Abliz
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- CAMS Key Laboratory of Molecular Mechanism and Target Discovery of Metabolic Disorder and Tumorigenesis, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuling Liu
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Drug Delivery Technology and Novel Formulation, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shuainan Liu
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- *Correspondence: Yi Huan, ; Shuainan Liu,
| | - Zhufang Shen
- Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
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Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
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8
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Dos Santos T, Galipeau M, Schukarucha Gomes A, Greenberg M, Larsen M, Lee D, Maghera J, Mulchandani CM, Patton M, Perera I, Polishevska K, Ramdass S, Shayeganpour K, Vafaeian K, Van Allen K, Wang Y, Weisz T, Estall JL, Mulvihill EE, Screaton RA. Islet Biology during COVID-19: Progress and Perspectives. Can J Diabetes 2021; 46:419-427. [PMID: 35589534 PMCID: PMC8608413 DOI: 10.1016/j.jcjd.2021.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/28/2021] [Accepted: 11/01/2021] [Indexed: 01/08/2023]
Abstract
The coronavirus-2019 (COVID-19) pandemic has had significant impact on research directions and productivity in the past 2 years. Despite these challenges, since 2020, more than 2,500 peer-reviewed articles have been published on pancreatic islet biology. These include updates on the roles of isocitrate dehydrogenase, pyruvate kinase and incretin hormones in insulin secretion, as well as the discovery of inceptor and signalling by circulating RNAs. The year 2020 also brought advancements in in vivo and in vitro models, including a new transgenic mouse for assessing beta-cell proliferation, a “pancreas-on-a-chip” to study glucose-stimulated insulin secretion and successful genetic editing of primary human islet cells. Islet biologists evaluated the functionality of stem-cell–derived islet-like cells coated with semipermeable biomaterials to prevent autoimmune attack, revealing the importance of cell maturation after transplantation. Prompted by observations that COVID-19 symptoms can worsen for people with obesity or diabetes, researchers examined how islets are directly affected by severe acute respiratory syndrome coronavirus 2. Herein, we highlight novel functional insights, technologies and therapeutic approaches that emerged between March 2020 and July 2021, written for both scientific and lay audiences. We also include a response to these advancements from patient stakeholders, to help lend a broader perspective to developments and challenges in islet research.
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Affiliation(s)
- Theodore Dos Santos
- Alberta Diabetes Institute & Department of Pharmacology, Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, Alberta, Canada
| | - Maria Galipeau
- Department of Molecular Biology, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada; Institut de recherches cliniques de Montréal, Cardiometabolic Disease Centre, Montréal, Québec, Canada
| | - Amanda Schukarucha Gomes
- Alberta Diabetes Institute & Department of Pharmacology, Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, Alberta, Canada
| | | | | | - Daniel Lee
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Jasmine Maghera
- Alberta Diabetes Institute & Department of Pharmacology, Li Ka Shing Centre for Health Research Innovation, University of Alberta, Edmonton, Alberta, Canada
| | | | - Megan Patton
- Toronto General Hospital, Toronto, Ontario, Canada
| | - Ineli Perera
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Kateryna Polishevska
- Alberta Diabetes Institute and Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
| | | | - Kasra Shayeganpour
- Alberta Diabetes Institute and Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
| | | | - Kyle Van Allen
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Yufeng Wang
- University Health Network, Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Tom Weisz
- Toronto General Hospital, Toronto, Ontario, Canada
| | - Jennifer L Estall
- Department of Molecular Biology, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada; Institut de recherches cliniques de Montréal, Cardiometabolic Disease Centre, Montréal, Québec, Canada
| | - Erin E Mulvihill
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, Ontario, Canada; Department of Biochemistry, Immunology and Microbiology, University of Ottawa, Ottawa, Ontario, Canada
| | - Robert A Screaton
- Sunnybrook Research Institute, Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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9
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Abstract
Transcription factor 7-like 2 (TCF7L2), a member of the T cell factor/lymphoid enhancer factor family, generally forms a complex with β-catenin to regulate the downstream target genes as an effector of the canonical Wnt signalling pathway. TCF7L2 plays a vital role in various biological processes and functions in many organs and tissues, including the liver, islet and adipose tissues. Further, TCF7L2 down-regulates hepatic gluconeogenesis and promotes lipid accumulation. In islets, TCF7L2 not only affects the insulin secretion of the β-cells but also has an impact on other cells. In addition, TCF7L2 influences adipogenesis in adipose tissues. Thus, an out-of-control TCF7L2 expression can result in metabolic disorders. The TCF7L2 gene is composed of 17 exons, generating 13 different transcripts, and has many single-nucleotide polymorphisms (SNPs). The discovery that these SNPs have an impact on the risk of type 2 diabetes (T2D) has attracted thorough investigations in the study of TCF7L2. Apart from T2D, TCF7L2 SNPs are also associated with type 1, posttransplant and other types of diabetes. Furthermore, TCF7L2 variants affect the progression of other disorders, such as obesity, cancers, metabolic syndrome and heart diseases. Finally, the interaction between TCF7L2 variants and diet also needs to be investigated.
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Affiliation(s)
- Zhensheng Zhang
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China.,Zhejiang University School of Medicine, Hangzhou, China
| | - Li Xu
- Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Zhejiang University Cancer Center, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China.,Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Xu
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Zhejiang University Cancer Center, Hangzhou, China
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10
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Abstract
Type 2 diabetes (T2D) is a worldwide serious public health problem. Insulin resistance and β-cell failure are the two major components of T2D pathology. In addition to defective endoplasmic reticulum (ER) stress signaling due to glucolipotoxicity, β-cell dysfunction or β-cell death initiates the deleterious vicious cycle observed in T2D. Although the primary cause is still unknown, overnutrition that contributes to the induction of the state of low-grade inflammation, and the activation of various protein kinases-related metabolic pathways are main factors leading to T2D. In this chapter following subjects, which have critical checkpoints regarding β-cell fate and protein kinases pathways are discussed; hyperglycemia-induced β-cell failure, chronic accumulation of unfolded protein in β-cells, the effect of intracellular reactive oxygen species (ROS) signaling to insulin secretion, excessive saturated free fatty acid-induced β-cell apoptosis, mitophagy dysfunction, proinflammatory responses and insulin resistance, and the reprogramming of β-cell for differentiation or dedifferentiation in T2D. There is much debate about selecting proposed therapeutic strategies to maintain or enhance optimal β-cell viability for adequate insulin secretion in T2D. However, in order to achieve an effective solution in the treatment of T2D, more intensive clinical trials are required on newer therapeutic options based on protein kinases signaling pathways.
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Affiliation(s)
- Ayse Basak Engin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
| | - Atilla Engin
- Department of General Surgery, Faculty of Medicine, Gazi University, Ankara, Turkey
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11
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Li TT, Zhu HB. LKB1 and cancer: The dual role of metabolic regulation. Biomed Pharmacother 2020; 132:110872. [PMID: 33068936 DOI: 10.1016/j.biopha.2020.110872] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [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: 07/01/2020] [Revised: 10/07/2020] [Accepted: 10/07/2020] [Indexed: 02/07/2023] Open
Abstract
Liver kinase B1 (LKB1) is an essential serine/threonine kinase frequently associated with Peutz-Jeghers syndrome (PJS). In this review, we provide an overview of the role of LKB1 in conferring protection to cancer cells against metabolic stress and promoting cancer cell survival and invasion. This carcinogenic effect contradicts the previous conclusion that LKB1 is a tumor suppressor gene. Here we try to explain the contradictory effect of LKB1 on cancer from a metabolic perspective. Upon deletion of LKB1, cancer cells experience increased energy as well as oxidative stress, thereby causing genomic instability. Meanwhile, mutated LKB1 cooperates with other metabolic regulatory genes to promote metabolic reprogramming that subsequently facilitates adaptation to strong metabolic stress, resulting in development of a more aggressive malignant phenotype. We aim to specifically discuss the contradictory role of LKB1 in cancer by reviewing the mechanism of LKB1 with an emphasis on metabolic stress and metabolic reprogramming.
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Affiliation(s)
- Ting-Ting Li
- Department of Gynecology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Hai-Bin Zhu
- Department of Gynecology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China.
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12
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Ulisse V, Dey S, Rothbard DE, Zeevi E, Gokhman I, Dadosh T, Minis A, Yaron A. Regulation of axonal morphogenesis by the mitochondrial protein Efhd1. Life Sci Alliance 2020; 3:3/7/e202000753. [PMID: 32414840 PMCID: PMC7232985 DOI: 10.26508/lsa.202000753] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022] Open
Abstract
During development, neurons adjust their energy balance to meet the high demands of robust axonal growth and branching. The mechanisms that regulate this tuning are largely unknown. Here, we show that sensory neurons lacking liver kinase B1 (Lkb1), a master regulator of energy homeostasis, exhibit impaired axonal growth and branching. Biochemical analysis of these neurons revealed reduction in axonal ATP levels, whereas transcriptome analysis uncovered down-regulation of Efhd1 (EF-hand domain family member D1), a mitochondrial Ca2+-binding protein. Genetic ablation of Efhd1 in mice resulted in reduced axonal morphogenesis as well as enhanced neuronal death. Strikingly, this ablation causes mitochondrial dysfunction and a decrease in axonal ATP levels. Moreover, Efhd1 KO sensory neurons display shortened mitochondria at the axonal growth cones, activation of the AMP-activated protein kinase (AMPK)-Ulk (Unc-51-like autophagy-activating kinase 1) pathway and an increase in autophagic flux. Overall, this work uncovers a new mitochondrial regulator that is required for axonal morphogenesis.
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Affiliation(s)
- Valeria Ulisse
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Swagata Dey
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Deborah E Rothbard
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Einav Zeevi
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Irena Gokhman
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Tali Dadosh
- Department of Chemical Research Support, Faculty of Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Adi Minis
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Avraham Yaron
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
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13
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Helman A, Cangelosi AL, Davis JC, Pham Q, Rothman A, Faust AL, Straubhaar JR, Sabatini DM, Melton DA. A Nutrient-Sensing Transition at Birth Triggers Glucose-Responsive Insulin Secretion. Cell Metab 2020; 31:1004-1016.e5. [PMID: 32375022 PMCID: PMC7480404 DOI: 10.1016/j.cmet.2020.04.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/14/2020] [Accepted: 03/31/2020] [Indexed: 12/31/2022]
Abstract
A drastic transition at birth, from constant maternal nutrient supply in utero to intermittent postnatal feeding, requires changes in the metabolic system of the neonate. Despite their central role in metabolic homeostasis, little is known about how pancreatic β cells adjust to the new nutritional challenge. Here, we find that after birth β cell function shifts from amino acid- to glucose-stimulated insulin secretion in correlation with the change in the nutritional environment. This adaptation is mediated by a transition in nutrient sensitivity of the mTORC1 pathway, which leads to intermittent mTORC1 activity. Disrupting nutrient sensitivity of mTORC1 in mature β cells reverts insulin secretion to a functionally immature state. Finally, manipulating nutrient sensitivity of mTORC1 in stem cell-derived β cells in vitro strongly enhances their glucose-responsive insulin secretion. These results reveal a mechanism by which nutrients regulate β cell function, thereby enabling a metabolic adaptation for the newborn.
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Affiliation(s)
- Aharon Helman
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Andrew L Cangelosi
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jeffrey C Davis
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Quan Pham
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Arielle Rothman
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Aubrey L Faust
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Juerg R Straubhaar
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
| | - Douglas A Melton
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Cambridge, MA 02139, USA.
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14
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Esch N, Jo S, Moore M, Alejandro EU. Nutrient Sensor mTOR and OGT: Orchestrators of Organelle Homeostasis in Pancreatic β-Cells. J Diabetes Res 2020; 2020:8872639. [PMID: 33457426 PMCID: PMC7787834 DOI: 10.1155/2020/8872639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/06/2020] [Accepted: 11/24/2020] [Indexed: 02/08/2023] Open
Abstract
The purpose of this review is to integrate the role of nutrient-sensing pathways into β-cell organelle dysfunction prompted by nutrient excess during type 2 diabetes (T2D). T2D encompasses chronic hyperglycemia, hyperlipidemia, and inflammation, which each contribute to β-cell failure. These factors can disrupt the function of critical β-cell organelles, namely, the ER, mitochondria, lysosomes, and autophagosomes. Dysfunctional organelles cause defects in insulin synthesis and secretion and activate apoptotic pathways if homeostasis is not restored. In this review, we will focus on mTORC1 and OGT, two major anabolic nutrient sensors with important roles in β-cell physiology. Though acute stimulation of these sensors frequently improves β-cell function and promotes adaptation to cell stress, chronic and sustained activity disturbs organelle homeostasis. mTORC1 and OGT regulate organelle function by influencing the expression and activities of key proteins, enzymes, and transcription factors, as well as by modulating autophagy to influence clearance of defective organelles. In addition, mTORC1 and OGT activity influence islet inflammation during T2D, which can further disrupt organelle and β-cell function. Therapies for T2D that fine-tune the activity of these nutrient sensors have yet to be developed, but the important role of mTORC1 and OGT in organelle homeostasis makes them promising targets to improve β-cell function and survival.
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Affiliation(s)
- Nicholas Esch
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Seokwon Jo
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mackenzie Moore
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Surgery, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Emilyn U. Alejandro
- Department of Integrative Biology & Physiology, University of Minnesota Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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15
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Huang Q, Gong Q, Wen T, Feng S, Xu J, Liu J, Han X, Liu Q, Hu J, Zhu L. Loss of LAMTOR1 in pancreatic β‑cells increases glucose‑stimulated insulin secretion in mice. Int J Mol Med 2019; 45:23-32. [PMID: 31939616 PMCID: PMC6889919 DOI: 10.3892/ijmm.2019.4409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 07/04/2019] [Indexed: 12/15/2022] Open
Abstract
Insulin secretion from pancreatic β-cells regulates glucose metabolism and is related to various diseases including diabetes. The late endosomal/lysosomal adaptor MAPK and mTOR activator 1 (LAMTOR1) is one of the subunits of the 'Ragulator' complex and plays an important role in energy metabolism including glucose metabolism. The present study was designed to explore the role of LAMTOR1 in murine pancreatic β-cell function. A murine model with β cell-specific deficiency (βLamtor1-KO) was generated to assess β-cell function (insulin sensitivity paired with β-cell responses) by hyperglycemic clamp in vivo. Islet perfusion and mitochondrial functional analyses were performed to investigate the individual steps in the insulin secretion pathway. Results showed that glucose tolerance in vivo as well as glucose-stimulated insulin secretion in the hyperglycemic clamp and islet perfusion were higher in βLamtor1-KO mice compared to the control models. Although mitochondrial dysfunction was present, the deletion of Lamtor1 increased glutamate content in the mouse insulin granules as well as acetyl-CoA carboxylase 1 (ACC1) activity thus enhancing insulin secretion. Together, our data indicate that LAMTOR1 is important for maintaining mitochondrial function in mouse pancreatic β-cells, however deletion of Lamtor1 increases the amplification pathway induced by glutamate and ACC1, ultimately leading to increased insulin secretion. These findings suggest that knockout of Lamtor1 is a potential technique for improving pancreatic β-cell function and treating diabetes.
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Affiliation(s)
- Qiong Huang
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Qi Gong
- Department of Center Laboratory, The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510000, P.R. China
| | - Ting Wen
- Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Shanshan Feng
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Jixiong Xu
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Jianying Liu
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Xiudan Han
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Qun Liu
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Juan Hu
- Department of Cardiovascular Medicine, Xiangya Hospital Central South University, Changsha, Hunan 410008, P.R. China
| | - Lingyan Zhu
- Department of Endocrinology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
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16
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Xu Y, Gao Y, Huang Z, Zheng Y, Teng W, Zheng D, Zheng X. LKB1 suppresses androgen synthesis in a mouse model of hyperandrogenism via IGF-1 signaling. FEBS Open Bio 2019; 9:1817-1825. [PMID: 31433577 PMCID: PMC6768104 DOI: 10.1002/2211-5463.12723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/30/2019] [Accepted: 08/19/2019] [Indexed: 12/12/2022] Open
Abstract
Polycystic ovary syndrome (PCOS) is a major cause of anovulatory sterility in women, and most PCOS patients exhibit hyperandrogenism (HA). Liver kinase b1 (LKB1) is a tumor suppressor that has recently been reported to be involved in PCOS. However, the mechanism by which LKB1 affects HA has not previously been elucidated. We report here that ovarian LKB1 levels are significantly decreased in a female mouse model of HA. Moreover, we report that LKB1 expression is inhibited by elevated androgens via activation of androgen receptors. In addition, LKB1 treatment was observed to suppress androgen synthesis in theca cells and promote estrogen production in granulosa cells by regulating steroidogenic enzyme expression. As expected, LKB1 knockdown inhibited estrogen levels and enhanced androgen levels, and LKB1‐transgenic mice were protected against HA. The effect of LKB1 appears to be mediated via IGF‐1 signaling. In summary, we describe here a key role for LKB1 in controlling sex hormone levels.
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Affiliation(s)
- Ying Xu
- Department of Obstetrics and Gynecology, the 476th Hospital of PLA, Fuzhou, China.,Fuzong Clinical College, Fujian Medical University, Fuzhou, China
| | - Yongxing Gao
- Department of Obstetrics and Gynecology, Zhongda Hospital Southeast University, Nanjing, China
| | - Zufang Huang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou, China
| | - Yan Zheng
- Department of Obstetrics and Gynecology, the 476th Hospital of PLA, Fuzhou, China
| | - Wenjuan Teng
- Department of Obstetrics and Gynecology, the 476th Hospital of PLA, Fuzhou, China
| | - Deyan Zheng
- Department of Obstetrics and Gynecology, the 476th Hospital of PLA, Fuzhou, China
| | - Xiaohua Zheng
- Department of Obstetrics and Gynecology, the 476th Hospital of PLA, Fuzhou, China
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17
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Evans AM. AMPK breathing and oxygen supply. Respir Physiol Neurobiol 2019; 265:112-20. [DOI: 10.1016/j.resp.2018.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/06/2018] [Accepted: 08/31/2018] [Indexed: 01/28/2023]
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18
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Kleiner S, Gomez D, Megra B, Na E, Bhavsar R, Cavino K, Xin Y, Rojas J, Dominguez-Gutierrez G, Zambrowicz B, Carrat G, Chabosseau P, Hu M, Murphy AJ, Yancopoulos GD, Rutter GA, Gromada J. Mice harboring the human SLC30A8 R138X loss-of-function mutation have increased insulin secretory capacity. Proc Natl Acad Sci U S A 2018; 115:E7642-9. [PMID: 30038024 DOI: 10.1073/pnas.1721418115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
SLC30A8 encodes a zinc transporter that is primarily expressed in the pancreatic islets of Langerhans. In β-cells it transports zinc into insulin-containing secretory granules. Loss-of-function (LOF) mutations in SLC30A8 protect against type 2 diabetes in humans. In this study, we generated a knockin mouse model carrying one of the most common human LOF mutations for SLC30A8, R138X. The R138X mice had normal body weight, glucose tolerance, and pancreatic β-cell mass. Interestingly, in hyperglycemic conditions induced by the insulin receptor antagonist S961, the R138X mice showed a 50% increase in insulin secretion. This effect was not associated with enhanced β-cell proliferation or mass. Our data suggest that the SLC30A8 R138X LOF mutation may exert beneficial effects on glucose metabolism by increasing the capacity of β-cells to secrete insulin under hyperglycemic conditions.
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19
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Nguyen-Tu MS, da Silva Xavier G, Leclerc I, Rutter GA. Transcription factor-7-like 2 ( TCF7L2) gene acts downstream of the Lkb1/ Stk11 kinase to control mTOR signaling, β cell growth, and insulin secretion. J Biol Chem 2018; 293:14178-14189. [PMID: 29967064 PMCID: PMC6130960 DOI: 10.1074/jbc.ra118.003613] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/15/2018] [Indexed: 12/25/2022] Open
Abstract
Variants in the transcription factor-7–like 2 (TCF7L2/TCF4) gene, involved in Wnt signaling, are associated with type 2 diabetes. Loss of Tcf7l2 selectively from the β cell in mice has previously been shown to cause glucose intolerance and to lower β cell mass. Deletion of the tumor suppressor liver kinase B1 (LKB1/STK11) leads to β cell hyperplasia and enhanced glucose-stimulated insulin secretion, providing a convenient genetic model for increased β cell growth and function. The aim of this study was to explore the possibility that Tcf7l2 may be required for the effects of Lkb1 deletion on insulin secretion in the mouse β cell. Mice bearing floxed Lkb1 and/or Tcf7l2 alleles were bred with knockin mice bearing Cre recombinase inserted at the Ins1 locus (Ins1Cre), allowing highly β cell–selective deletion of either or both genes. Oral glucose tolerance was unchanged by the further deletion of a single Tcf7l2 allele in these cells. By contrast, mice lacking both Tcf7l2 alleles on this background showed improved oral glucose tolerance and insulin secretion in vivo and in vitro compared with mice lacking a single Tcf7l2 allele. Biallelic Tcf7l2 deletion also enhanced β cell proliferation, increased β cell mass, and caused changes in polarity as revealed by the “rosette-like” arrangement of β cells. Tcf7l2 deletion also increased signaling by mammalian target of rapamycin (mTOR), augmenting phospho-ribosomal S6 levels. We identified a novel signaling mechanism through which a modifier gene, Tcf7l2, lies on a pathway through which LKB1 acts in the β cell to restrict insulin secretion.
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Affiliation(s)
- Marie-Sophie Nguyen-Tu
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Gabriela da Silva Xavier
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Isabelle Leclerc
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Guy A Rutter
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
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20
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Affourtit C, Alberts B, Barlow J, Carré JE, Wynne AG. Control of pancreatic β-cell bioenergetics. Biochem Soc Trans 2018; 46:555-64. [PMID: 29666215 DOI: 10.1042/BST20170505] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 12/12/2022]
Abstract
The canonical model of glucose-stimulated insulin secretion (GSIS) by pancreatic β-cells predicts a glucose-induced rise in the cytosolic ATP/ADP ratio. Such bioenergetic sensitivity to metabolic fuel is unusual as it implies that ATP flux is governed, to a significant extent, by ATP supply, while it is predominantly demand-driven in other cell types. Metabolic control is generally shared between different processes, but potential control of ATP consumption over β-cell bioenergetics has been largely ignored to date. The present paper offers a brief overview of experimental evidence that demonstrates ATP flux control by glucose-fuelled oxidative phosphorylation. Based on old and new data, it is argued that ATP supply does not hold exclusive control over ATP flux, but shares it with ATP demand, and that the distribution of control is flexible. Quantification of the bioenergetic control distribution will be important from basic and clinical perspectives, but precise measurement of the cytosolic ATP/ADP ratio is complicated by adenine nucleotide compartmentalisation. Metabolic control analysis of β-cell bioenergetics will likely clarify the mechanisms by which glucose and fatty acids amplify and potentiate GSIS, respectively. Moreover, such analysis may offer hints as to how ATP flux control shifts from ATP supply to ATP demand during the development of type 2 diabetes, and why prolonged sulfonylurea treatment causes β-cell deterioration.
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21
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Abstract
If left unchecked, prediabetic hyperglycemia can progress to diabetes and often life-threatening attendant secondary complications. Central to the process of glucose homeostasis are pancreatic β cells, which sense elevations in plasma glucose and additional dietary components and respond by releasing the appropriate quantity of insulin, ensuring the arrest of hepatic glucose output and glucose uptake in peripheral tissues. Given that β cell failure is associated with the transition from prediabetes to diabetes, improved β cell function ('compensation') has a central role in preventing type 2 diabetes mellitus (T2DM). Recent data have shown that both insulin secretion and β cell mass dynamics are regulated by the liver kinase B1-AMP-activated kinase (LKB1-AMPK) pathway and related kinases of the AMPK family; thus, an improved understanding of the biological roles of AMPK in the β cell is now of considerable interest.
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Affiliation(s)
- Jillian L Rourke
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ONT, M4N 3M5, Canada
| | - Queenie Hu
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ONT, M4N 3M5, Canada
| | - Robert A Screaton
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ONT, M4N 3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, ONT, M5S 1A8, Canada.
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22
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Rozentul N, Avrahami Y, Shubely M, Levy L, Munder A, Cohen G, Cerasi E, Sasson S, Gruzman A. A Novel Phenylchromane Derivative Increases the Rate of Glucose Uptake in L6 Myotubes and Augments Insulin Secretion from Pancreatic Beta-Cells by Activating AMPK. Pharm Res 2017; 34:2873-90. [DOI: 10.1007/s11095-017-2271-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/24/2017] [Indexed: 01/04/2023]
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23
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Lamontagne J, Al-Mass A, Nolan CJ, Corkey BE, Madiraju SRM, Joly E, Prentki M. Identification of the signals for glucose-induced insulin secretion in INS1 (832/13) β-cells using metformin-induced metabolic deceleration as a model. J Biol Chem 2017; 292:19458-19468. [PMID: 28972173 DOI: 10.1074/jbc.m117.808105] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/13/2017] [Indexed: 12/23/2022] Open
Abstract
Metabolic deceleration in pancreatic β-cells is associated with inhibition of glucose-induced insulin secretion (GIIS), but only in the presence of intermediate/submaximal glucose concentrations. Here, we used acute metformin treatment as a tool to induce metabolic deceleration in INS1 (832/13) β-cells, with the goal of identifying key pathways and metabolites involved in GIIS. Metabolites and pathways previously implicated as signals for GIIS were measured in the cells at 2-25 mm glucose, with or without 5 mm metformin. We defined three criteria to identify candidate signals: 1) glucose-responsiveness, 2) sensitivity to metformin-induced inhibition of the glucose effect at intermediate glucose concentrations, and 3) alleviation of metformin inhibition by elevated glucose concentrations. Despite the lack of recovery from metformin-induced impairment of mitochondrial energy metabolism (glucose oxidation, O2 consumption, and ATP production), insulin secretion was almost completely restored at elevated glucose concentrations. Meeting the criteria for candidates involved in promoting GIIS were the following metabolic indicators and metabolites: cytosolic NAD+/NADH ratio (inferred from the dihydroxyacetone phosphate:glycerol-3-phosphate ratio), mitochondrial membrane potential, ADP, Ca2+, 1-monoacylglycerol, diacylglycerol, malonyl-CoA, and HMG-CoA. On the contrary, most of the purine and nicotinamide nucleotides, acetoacetyl-CoA, H2O2, reduced glutathione, and 2-monoacylglycerol were not glucose-responsive. Overall these results underscore the significance of mitochondrial energy metabolism-independent signals in GIIS regulation; in particular, the candidate lipid signaling molecules 1-monoacylglycerol, diacylglycerol, and malonyl-CoA; the predominance of KATP/Ca2+ signaling control by low ADP·Mg2+ rather than by high ATP levels; and a role for a more oxidized state (NAD+/NADH) in the cytosol during GIIS that favors high glycolysis rates.
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Affiliation(s)
- Julien Lamontagne
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada
| | - Anfal Al-Mass
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada.,the Department of Medicine, McGill University, Montréal, Québec H4A 3J1, Canada
| | - Christopher J Nolan
- the Department of Endocrinology, Canberra Hospital and the Medical School, Australian National University, Canberra ACT 2605, Australia, and
| | - Barbara E Corkey
- the Department of Medicine, Obesity Research Center, Boston University School of Medicine, Boston, Massachusetts 02118
| | - S R Murthy Madiraju
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada
| | - Erik Joly
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada
| | - Marc Prentki
- From the Molecular Nutrition Unit and Montreal Diabetes Research Center, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec H2X 0A9, Canada, .,the Departments of Nutrition and Biochemistry, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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24
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钟 超, 彭 亮, 李 冉, 陈 静, 陈 新, 曾 笛, 徐 晓, 王 志, 陈 楚, 王 亚, 李 爱, 刘 思, 吴 保. [LKB1 regulates epithelial-mesenchymal transition in Peutz-Jeghers hamartoma and intestinal epithelial cells]. Nan Fang Yi Ke Da Xue Xue Bao 2017; 37:1078-1084. [PMID: 28801289 PMCID: PMC6765722 DOI: 10.3969/j.issn.1673-4254.2017.08.13] [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] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To investigate the molecular mechanism by which LKB1 regulates epithelial-mesenchymal transition (EMT) in Peutz-Jeghers hamartoma and intestinal epithelial cells. METHODS Immunohistochemistry was used to detect gene expression of LKB1, E-cadherin, and vimentin in 20 hamartoma tissues and 10 normal intestinal tissues, and collagen fiber deposition was analyzed using Masson trichrome staining. Normal intestinal epithelial NCM460 cells were transfected with LKB1 shRNA plasmid or negative control via lentiviral vectors, and the role of LKB1 in cell polarization and migration were determined using CCK8 and Transwell assays. Western blotting, quantitative real-time PCR (qPCR) and immunofluorescence were used to assess the alterations of EMT markers in the cells with LKB1 knockdown. RESULTS Compared with normal intestinal tissues, hamartoma polyps showed significantly decreased LKB1 and E-cadherin expressions and increased vimentin expression with increased collagen fiber deposition. The cells with LKB1 knockdown exhibited enhanced cell proliferation and migration activities (P<0.01). Western blot analysis, qPCR and immunofluorescence all detected decreased E-cadherin and increased N-cadherin, vimentin, Snail, and Slug expressions in the cells with LKB1 knockdown. CONCLUSION s LKB1 deficiency triggers EMT in intestinal epithelial cells and Peutz-Jeghers hamartoma, suggesting that EMT can serve as the therapeutic target for treatment of Peutz-Jeghers syndrome.
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Affiliation(s)
- 超 钟
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 亮 彭
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 冉 李
- 青岛大学附属医院感染科, 山东 青岛 370200Department of Infectious Disease, Qingdao University Affiliated Hospital, Qingdao 370200, China
| | - 静 陈
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 新琦 陈
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 笛 曾
- 广东省广州市番禺区人民医院消化内科, 广东 广州 510000Department of Gastroenterology, Guangzhou Panyu Central Hospital, Guangzhou 510000, China
| | - 晓平 徐
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 志青 王
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 楚弟 陈
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 亚东 王
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 爱民 李
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 思德 刘
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - 保平 吴
- 南方医科大学南方医院消化内科//广东省胃肠疾病重点实验室, 广东 广州 510515Guangdong Provincial Key Laboratory of Gastroenterology/Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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25
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Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
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Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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26
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Cruciani-Guglielmacci C, Bellini L, Denom J, Oshima M, Fernandez N, Normandie-Levi P, Berney XP, Kassis N, Rouch C, Dairou J, Gorman T, Smith DM, Marley A, Liechti R, Kuznetsov D, Wigger L, Burdet F, Lefèvre AL, Wehrle I, Uphues I, Hildebrandt T, Rust W, Bernard C, Ktorza A, Rutter GA, Scharfmann R, Xenarios I, Le Stunff H, Thorens B, Magnan C, Ibberson M. Molecular phenotyping of multiple mouse strains under metabolic challenge uncovers a role for Elovl2 in glucose-induced insulin secretion. Mol Metab 2017; 6:340-351. [PMID: 28377873 PMCID: PMC5369210 DOI: 10.1016/j.molmet.2017.01.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 01/16/2017] [Accepted: 01/20/2017] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE In type 2 diabetes (T2D), pancreatic β cells become progressively dysfunctional, leading to a decline in insulin secretion over time. In this study, we aimed to identify key genes involved in pancreatic beta cell dysfunction by analyzing multiple mouse strains in parallel under metabolic stress. METHODS Male mice from six commonly used non-diabetic mouse strains were fed a high fat or regular chow diet for three months. Pancreatic islets were extracted and phenotypic measurements were recorded at 2 days, 10 days, 30 days, and 90 days to assess diabetes progression. RNA-Seq was performed on islet tissue at each time-point and integrated with the phenotypic data in a network-based analysis. RESULTS A module of co-expressed genes was selected for further investigation as it showed the strongest correlation to insulin secretion and oral glucose tolerance phenotypes. One of the predicted network hub genes was Elovl2, encoding Elongase of very long chain fatty acids 2. Elovl2 silencing decreased glucose-stimulated insulin secretion in mouse and human β cell lines. CONCLUSION Our results suggest a role for Elovl2 in ensuring normal insulin secretory responses to glucose. Moreover, the large comprehensive dataset and integrative network-based approach provides a new resource to dissect the molecular etiology of β cell failure under metabolic stress.
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Affiliation(s)
- Céline Cruciani-Guglielmacci
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Lara Bellini
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Jessica Denom
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Masaya Oshima
- INSERM U1016, Université Paris-Descartes, Institut Cochin, Paris, France
| | - Neïké Fernandez
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Priscilla Normandie-Levi
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Xavier P Berney
- Centre for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nadim Kassis
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Claude Rouch
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Julien Dairou
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France
| | - Tracy Gorman
- Discovery Sciences, Innovative Medicines & Early Development Biotech Unit, AstraZeneca, Cambridge Science Park, Milton Road, Cambridge CB4 0WG, UK
| | - David M Smith
- Discovery Sciences, Innovative Medicines & Early Development Biotech Unit, AstraZeneca, Cambridge Science Park, Milton Road, Cambridge CB4 0WG, UK
| | - Anna Marley
- Discovery Sciences, Innovative Medicines & Early Development Biotech Unit, AstraZeneca, Cambridge Science Park, Milton Road, Cambridge CB4 0WG, UK
| | - Robin Liechti
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Dmitry Kuznetsov
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Leonore Wigger
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Frédéric Burdet
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Anne-Laure Lefèvre
- Recherche de Découverte, PIT Métabolisme, IdRS, 11 rue des Moulineaux, 92150 Suresnes, France
| | - Isabelle Wehrle
- Recherche de Découverte, PIT Métabolisme, IdRS, 11 rue des Moulineaux, 92150 Suresnes, France
| | - Ingo Uphues
- Boehringer Ingelheim Pharma GmbH & Co, KG 88400 Biberach, Germany
| | | | - Werner Rust
- Boehringer Ingelheim Pharma GmbH & Co, KG 88400 Biberach, Germany
| | - Catherine Bernard
- Recherche de Découverte, PIT Métabolisme, IdRS, 11 rue des Moulineaux, 92150 Suresnes, France
| | - Alain Ktorza
- Recherche de Découverte, PIT Métabolisme, IdRS, 11 rue des Moulineaux, 92150 Suresnes, France
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London W120NN, UK
| | - Raphael Scharfmann
- INSERM U1016, Université Paris-Descartes, Institut Cochin, Paris, France
| | - Ioannis Xenarios
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Hervé Le Stunff
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France; I2BC - UMR 9198 Université Paris Sud, Gif sur Yvette, France
| | - Bernard Thorens
- Centre for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Christophe Magnan
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, Université Paris Diderot, Paris, France.
| | - Mark Ibberson
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
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Shan T, Xiong Y, Kuang S. Deletion of Lkb1 in adult mice results in body weight reduction and lethality. Sci Rep 2016; 6:36561. [PMID: 27824128 DOI: 10.1038/srep36561] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/18/2016] [Indexed: 12/22/2022] Open
Abstract
Liver kinase B1 (Lkb1) plays crucial roles in development, metabolism and survival. As constitutive knockout of Lkb1 in mice leads to embryonic lethality, whether Lkb1 is required for the growth and survival of adult mice is unclear. Here we address this question using a tamoxifen-inducible Lkb1 knockout (KO) mouse model: Rosa26-CreER: Lkb1flox/flox (abbreviated as Rosa-Lkb1). The Rosa-Lkb1 mice exhibited body weight reduction and died within 6 weeks after tamoxifen induction. The body weight reduction was due to reduced weight of various tissues but the brown and white adipose tissues underwent much more pronounced weight reduction relative to the overall body weight reduction. Accordingly, the Rosa-Lkb1 mice had increased blood glucose levels and were intolerant to glucose challenge. Expression levels of adipogenic and lipogenic genes in adipose tissues were also dramatically reduced by Lkb1 deletion. Additionally, Lkb1 deletion reduced lipid deposition and increased expression of mitochondrial (Pgc1a, Cox5b and Cox7a) and hepatic gluconeogenesis related genes (Pepck) in liver. Finally, the Rosa-Lkb1 mice had much reduced oxygen consumption, carbon dioxide production, and energy expenditure. These results demonstrate that Lkb1 plays an important role in maintaining body weight, liver and adipose tissue function, blood glucose homeostasis and survival in adult mice.
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28
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Evans AM, Mahmoud AD, Moral-Sanz J, Hartmann S. The emerging role of AMPK in the regulation of breathing and oxygen supply. Biochem J 2016; 473:2561-72. [PMID: 27574022 PMCID: PMC5003690 DOI: 10.1042/bcj20160002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/20/2016] [Accepted: 05/03/2016] [Indexed: 01/25/2023]
Abstract
Regulation of breathing is critical to our capacity to accommodate deficits in oxygen availability and demand during, for example, sleep and ascent to altitude. It is generally accepted that a fall in arterial oxygen increases afferent discharge from the carotid bodies to the brainstem and thus delivers increased ventilatory drive, which restores oxygen supply and protects against hypoventilation and apnoea. However, the precise molecular mechanisms involved remain unclear. We recently identified as critical to this process the AMP-activated protein kinase (AMPK), which is key to the cell-autonomous regulation of metabolic homoeostasis. This observation is significant for many reasons, not least because recent studies suggest that the gene for the AMPK-α1 catalytic subunit has been subjected to natural selection in high-altitude populations. It would appear, therefore, that evolutionary pressures have led to AMPK being utilized to regulate oxygen delivery and thus energy supply to the body in the short, medium and longer term. Contrary to current consensus, however, our findings suggest that AMPK regulates ventilation at the level of the caudal brainstem, even when afferent input responses from the carotid body are normal. We therefore hypothesize that AMPK integrates local hypoxic stress at defined loci within the brainstem respiratory network with an index of peripheral hypoxic status, namely afferent chemosensory inputs. Allied to this, AMPK is critical to the control of hypoxic pulmonary vasoconstriction and thus ventilation-perfusion matching at the lungs and may also determine oxygen supply to the foetus by, for example, modulating utero-placental blood flow.
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Affiliation(s)
- A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K.
| | - Amira D Mahmoud
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
| | - Javier Moral-Sanz
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
| | - Sandy Hartmann
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
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Tao HY, Qu ZY, Wei GM, Sheng J, Wang WL, Wan LX. Role of LKB1 in proliferation and apoptosis of gastric cancer cells. Shijie Huaren Xiaohua Zazhi 2016; 24:3262-3269. [DOI: 10.11569/wcjd.v24.i21.3262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the role of LKB1 in gastric cancer cells and the related mechanism.
METHODS: Real-time PCR and Western blot were used to detect the expression of LKB1 in SGC7901 cells carrying LKB1 expression vector or siRNA against LKB1. Flow cytometry was used to detect the apoptosis of SGC7901 cells after LKB1 overexpression or knockdown. Reactive oxygen detection kits were applied to detect the impact of LKB1 on ROS production. MTT method was used to determine intracellular ROS production after NAC inhibition. Western blot was used to detect the expression of apoptosis related proteins in SGC7901 cells after LKB1 overexpression or knockdown.
RESULTS: LKB1 expression was efficiently enhanced or silenced by LKB1 expression vector or siRNA against LKB1, respectively. The number of SGC7901 cells decreased as its proliferation rate decreased and apoptosis rate increased (3.54% vs 1.29%). Intracellular ROS production was increased but blunted by the use of NAC. The apoptosis of SGC7901 cells was significantly reduced following the inhibition of intracellular ROS, but the siRNA transfected group exhibited an opposite trend. Western blot analysis showed that LKB1 overexpression up-regulated the expression of cleaved Caspase3 in SGC7901 cells significantly (about 3.12 times), compared with control cells, but the expression of cleaved Caspase3 in the siRNA transfected group was decreased.
CONCLUSION: LKB1 raises the production of ROS and up-regulates the expression of cleaved Caspase3 to promote gastric cancer cell apoptosis. Hence, LKB1 plays an important role in the development of gastric cancer and it may be a valuable target for chemotherapy of gastric cancer.
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30
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Affiliation(s)
| | - Lieven Thorrez
- Gene Expression Unit, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven B3000, Belgium; , ,
| | - Frans Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, Leuven B3000, Belgium; , ,
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31
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Cunniff B, McKenzie AJ, Heintz NH, Howe AK. AMPK activity regulates trafficking of mitochondria to the leading edge during cell migration and matrix invasion. Mol Biol Cell 2016; 27:2662-74. [PMID: 27385336 PMCID: PMC5007087 DOI: 10.1091/mbc.e16-05-0286] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/26/2016] [Indexed: 01/06/2023] Open
Abstract
Mitochondria infiltrate leading edge lamellipodia, increasing local mitochondrial mass and relative ATP concentration. AMPK regulates infiltration of mitochondria into the leading edge of 2D lamellipodia and 3D invadopodia, coupling local metabolic sensing to subcellular targeting of mitochondria during cell movement. Cell migration is a complex behavior involving many energy-expensive biochemical events that iteratively alter cell shape and location. Mitochondria, the principal producers of cellular ATP, are dynamic organelles that fuse, divide, and relocate to respond to cellular metabolic demands. Using ovarian cancer cells as a model, we show that mitochondria actively infiltrate leading edge lamellipodia, thereby increasing local mitochondrial mass and relative ATP concentration and supporting a localized reversal of the Warburg shift toward aerobic glycolysis. This correlates with increased pseudopodial activity of the AMP-activated protein kinase (AMPK), a critically important cellular energy sensor and metabolic regulator. Furthermore, localized pharmacological activation of AMPK increases leading edge mitochondrial flux, ATP content, and cytoskeletal dynamics, whereas optogenetic inhibition of AMPK halts mitochondrial trafficking during both migration and the invasion of three-dimensional extracellular matrix. These observations indicate that AMPK couples local energy demands to subcellular targeting of mitochondria during cell migration and invasion.
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Affiliation(s)
- Brian Cunniff
- Department of Pathology, University of Vermont, Burlington, VT 05405 University of Vermont Cancer Center, University of Vermont, Burlington, VT 05405
| | - Andrew J McKenzie
- University of Vermont Cancer Center, University of Vermont, Burlington, VT 05405 Department of Pharmacology, University of Vermont, Burlington, VT 05405
| | - Nicholas H Heintz
- Department of Pathology, University of Vermont, Burlington, VT 05405 University of Vermont Cancer Center, University of Vermont, Burlington, VT 05405
| | - Alan K Howe
- University of Vermont Cancer Center, University of Vermont, Burlington, VT 05405 Department of Pharmacology, University of Vermont, Burlington, VT 05405
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32
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Shorning BY, Clarke AR. Energy sensing and cancer: LKB1 function and lessons learnt from Peutz-Jeghers syndrome. Semin Cell Dev Biol 2016; 52:21-9. [PMID: 26877140 DOI: 10.1016/j.semcdb.2016.02.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/08/2016] [Accepted: 02/08/2016] [Indexed: 12/31/2022]
Abstract
We describe in this review increasing evidence that loss of LKB1 kinase in Peutz-Jeghers syndrome (PJS) derails the existing natural balance between cell survival and tumour growth suppression. LKB1 deletion can plunge cells into an energy/oxidative stress-induced crisis which leads to the activation of alternative and often carcinogenic pathways to maintain cellular energy levels. It therefore appears that although LKB1 deficiency can suppress oncogenic transformation in the short term, it can ultimately lead to more progressed and malignant phenotypes by driving abnormal cell differentiation, genomic instability and increased tumour heterogeneity.
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Affiliation(s)
- Boris Y Shorning
- European Cancer Stem Cell Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, United Kingdom.
| | - Alan R Clarke
- European Cancer Stem Cell Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, United Kingdom
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Barlow J, Jensen VH, Jastroch M, Affourtit C. Palmitate-induced impairment of glucose-stimulated insulin secretion precedes mitochondrial dysfunction in mouse pancreatic islets. Biochem J 2016; 473:487-96. [PMID: 26621874 DOI: 10.1042/BJ20151080] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/30/2015] [Indexed: 01/08/2023]
Abstract
It has been well established that excessive levels of glucose and palmitate lower glucose-stimulated insulin secretion (GSIS) by pancreatic β-cells. This β-cell 'glucolipotoxicity' is possibly mediated by mitochondrial dysfunction, but involvement of bioenergetic failure in the pathological mechanism is the subject of ongoing debate. We show in the present study that increased palmitate levels impair GSIS before altering mitochondrial function. We demonstrate that GSIS defects arise from increased insulin release under basal conditions in addition to decreased insulin secretion under glucose-stimulatory conditions. Real-time respiratory analysis of intact mouse pancreatic islets reveals that mitochondrial ATP synthesis is not involved in the mechanism by which basal insulin is elevated. Equally, mitochondrial lipid oxidation and production of reactive oxygen species (ROS) do not contribute to increased basal insulin secretion. Palmitate does not affect KCl-induced insulin release at a basal or stimulatory glucose level, but elevated basal insulin release is attenuated by palmitoleate and associates with increased intracellular calcium. These findings deepen our understanding of β-cell glucolipotoxicity and reveal that palmitate-induced GSIS impairment is disconnected from mitochondrial dysfunction, a notion that is important when targeting β-cells for the treatment of diabetes and when assessing islet function in human transplants.
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