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Blutke A, Renner S, Flenkenthaler F, Backman M, Haesner S, Kemter E, Ländström E, Braun-Reichhart C, Albl B, Streckel E, Rathkolb B, Prehn C, Palladini A, Grzybek M, Krebs S, Bauersachs S, Bähr A, Brühschwein A, Deeg CA, De Monte E, Dmochewitz M, Eberle C, Emrich D, Fux R, Groth F, Gumbert S, Heitmann A, Hinrichs A, Keßler B, Kurome M, Leipig-Rudolph M, Matiasek K, Öztürk H, Otzdorff C, Reichenbach M, Reichenbach HD, Rieger A, Rieseberg B, Rosati M, Saucedo MN, Schleicher A, Schneider MR, Simmet K, Steinmetz J, Übel N, Zehetmaier P, Jung A, Adamski J, Coskun Ü, Hrabě de Angelis M, Simmet C, Ritzmann M, Meyer-Lindenberg A, Blum H, Arnold GJ, Fröhlich T, Wanke R, Wolf E. The Munich MIDY Pig Biobank - A unique resource for studying organ crosstalk in diabetes. Mol Metab 2017; 6:931-940. [PMID: 28752056 PMCID: PMC5518720 DOI: 10.1016/j.molmet.2017.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/05/2017] [Accepted: 06/06/2017] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE The prevalence of diabetes mellitus and associated complications is steadily increasing. As a resource for studying systemic consequences of chronic insulin insufficiency and hyperglycemia, we established a comprehensive biobank of long-term diabetic INSC94Y transgenic pigs, a model of mutant INS gene-induced diabetes of youth (MIDY), and of wild-type (WT) littermates. METHODS Female MIDY pigs (n = 4) were maintained with suboptimal insulin treatment for 2 years, together with female WT littermates (n = 5). Plasma insulin, C-peptide and glucagon levels were regularly determined using specific immunoassays. In addition, clinical chemical, targeted metabolomics, and lipidomics analyses were performed. At age 2 years, all pigs were euthanized, necropsied, and a broad spectrum of tissues was taken by systematic uniform random sampling procedures. Total beta cell volume was determined by stereological methods. A pilot proteome analysis of pancreas, liver, and kidney cortex was performed by label free proteomics. RESULTS MIDY pigs had elevated fasting plasma glucose and fructosamine concentrations, C-peptide levels that decreased with age and were undetectable at 2 years, and an 82% reduced total beta cell volume compared to WT. Plasma glucagon and beta hydroxybutyrate levels of MIDY pigs were chronically elevated, reflecting hallmarks of poorly controlled diabetes in humans. In total, ∼1900 samples of different body fluids (blood, serum, plasma, urine, cerebrospinal fluid, and synovial fluid) as well as ∼17,000 samples from ∼50 different tissues and organs were preserved to facilitate a plethora of morphological and molecular analyses. Principal component analyses of plasma targeted metabolomics and lipidomics data and of proteome profiles from pancreas, liver, and kidney cortex clearly separated MIDY and WT samples. CONCLUSIONS The broad spectrum of well-defined biosamples in the Munich MIDY Pig Biobank that will be available to the scientific community provides a unique resource for systematic studies of organ crosstalk in diabetes in a multi-organ, multi-omics dimension.
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Key Words
- Biobank
- CE, cholesterol ester
- CPT1, carnitine O-palmitoyltransferase 1
- ER, endoplasmic reticulum
- FFA, free fatty acids
- Hyperglycemia
- Insulin insufficiency
- MIDY
- MIDY, mutant INS gene-induced diabetes of youth
- Metabolomics
- PC, phosphatidylcholine
- PCA, principal component analysis
- Pig model
- Proteomics
- Random systematic sampling
- SM, sphingomyelin
- Stereology
- TAG, triacylglycerol
- Transcriptomics
- WT, wild-type
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Affiliation(s)
- Andreas Blutke
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Simone Renner
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany; German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | - Florian Flenkenthaler
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Mattias Backman
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Serena Haesner
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Elisabeth Kemter
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Erik Ländström
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Christina Braun-Reichhart
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Barbara Albl
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Elisabeth Streckel
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Birgit Rathkolb
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany; German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; German Mouse Clinic (GMC), Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | - Cornelia Prehn
- Genome Analysis Center (GAC), Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | - Alessandra Palladini
- German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Fetscherstr. 74, D-01307 Dresden, Germany
| | - Michal Grzybek
- German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Fetscherstr. 74, D-01307 Dresden, Germany
| | - Stefan Krebs
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Stefan Bauersachs
- Animal Physiology, Institute of Agricultural Sciences, ETH Zurich, Universitätsstr. 2, CH-8092 Zurich, Switzerland
| | - Andrea Bähr
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Andreas Brühschwein
- Clinic for Small Animal Surgery and Reproduction, Center for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Cornelia A Deeg
- Experimental Ophthalmology, Philipps University of Marburg, Baldingerstr., D-35033 Marburg, Germany; Chair for Animal Physiology, Department of Veterinary Sciences, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Erica De Monte
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Michaela Dmochewitz
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Caroline Eberle
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Daniela Emrich
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Robert Fux
- Institute for Infectious Diseases and Zoonosis, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Frauke Groth
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Sophie Gumbert
- Clinic for Swine at the Centre of Clinical Veterinary Medicine, LMU Munich, Sonnenstr. 16, D-85764 Oberschleißheim, Germany
| | - Antonia Heitmann
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Arne Hinrichs
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Barbara Keßler
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Mayuko Kurome
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Miriam Leipig-Rudolph
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Kaspar Matiasek
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany; Munich Center of NeuroSciences - Brain & Mind, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany
| | - Hazal Öztürk
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Christiane Otzdorff
- Clinic for Small Animal Surgery and Reproduction, Center for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Myriam Reichenbach
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Horst Dieter Reichenbach
- Bavarian State Research Center for Agriculture - Institute for Animal Breeding, Prof.-Dürrwaechter-Platz 1, D-85586 Grub-Poing, Germany
| | - Alexandra Rieger
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Birte Rieseberg
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Marco Rosati
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Manuel Nicolas Saucedo
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Anna Schleicher
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Marlon R Schneider
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Kilian Simmet
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Judith Steinmetz
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Nicole Übel
- Clinic for Swine at the Centre of Clinical Veterinary Medicine, LMU Munich, Sonnenstr. 16, D-85764 Oberschleißheim, Germany
| | - Patrizia Zehetmaier
- Chair for Animal Physiology, Department of Veterinary Sciences, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Andreas Jung
- Institute of Pathology, LMU Munich, Thalkirchner Str. 36, D-80337 Munich, Germany
| | - Jerzy Adamski
- Genome Analysis Center (GAC), Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | - Ünal Coskun
- German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus of TU Dresden, Fetscherstr. 74, D-01307 Dresden, Germany
| | - Martin Hrabě de Angelis
- German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; German Mouse Clinic (GMC), Institute of Experimental Genetics, Helmholtz Zentrum München, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany
| | | | - Mathias Ritzmann
- Clinic for Swine at the Centre of Clinical Veterinary Medicine, LMU Munich, Sonnenstr. 16, D-85764 Oberschleißheim, Germany
| | - Andrea Meyer-Lindenberg
- Clinic for Small Animal Surgery and Reproduction, Center for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Georg J Arnold
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Thomas Fröhlich
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
| | - Rüdiger Wanke
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, LMU Munich, Veterinärstr. 13, D-80539 Munich, Germany
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center and Department of Veterinary Sciences, and Center for Innovative Medical Models (CiMM), LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany; German Center for Diabetes Research (DZD), Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany; Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377 Munich, Germany.
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Wang Y, Ding Y, Li J, Chavan H, Matye D, Ni HM, Chiang JY, Krishnamurthy P, Ding WX, Li T. Targeting the Enterohepatic Bile Acid Signaling Induces Hepatic Autophagy via a CYP7A1-AKT-mTOR Axis in Mice. Cell Mol Gastroenterol Hepatol 2016; 3:245-260. [PMID: 28275691 PMCID: PMC5331786 DOI: 10.1016/j.jcmgh.2016.10.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/13/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Hepatic cholesterol accumulation and autophagy defects contribute to hepatocyte injury in fatty liver disease. Bile acid synthesis is a major pathway for cholesterol catabolism in the liver. This study aims to understand the molecular link between cholesterol and bile acid metabolism and hepatic autophagy activity. METHODS The effects of cholesterol and cholesterol 7α-hydroxylase (CYP7A1) expression on autophagy and lysosome function were studied in cell models. The effects and mechanism of disrupting enterohepatic bile acid circulation on hepatic autophagy were studied in mice. RESULTS The results first showed differential regulation of hepatic autophagy by free cholesterol and cholesterol ester, whereby a modest increase of cellular free cholesterol, but not cholesterol ester, impaired lysosome function and caused marked autolysosome accumulation. We found that CYP7A1 induction, either by cholestyramine feeding in mice or adenovirus-mediated CYP7A1 expression in hepatocytes, caused strong autophagy induction. Mechanistically, we showed that CYP7A1 expression markedly attenuated growth factor/AKT signaling activation of mechanistic target of rapamycin (mTOR), but not amino acid signaling to mTOR in vitro and in vivo. Metabolomics analysis further found that CYP7A1 induction not only decreased hepatic cholesterol but also altered phospholipid and sphingolipid compositions. Collectively, these results suggest that CYP7A1 induction interferes with growth factor activation of AKT/mTOR signaling possibly by altering membrane lipid composition. Finally, we showed that cholestyramine feeding restored impaired hepatic autophagy and improved metabolic homeostasis in Western diet-fed mice. CONCLUSIONS This study identified a novel CYP7A1-AKT-mTOR signaling axis that selectively induces hepatic autophagy, which helps improve hepatocellular integrity and metabolic homeostasis.
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Key Words
- 4EBP-1, eukaryotic translation initiation factor 4E-binding protein 1
- ACAT, acyl-CoA:cholesterol acyltransferase
- CE, cholesterol ester
- CQ, chloroquine
- CYP7A1, cholesterol 7α-hydroxylase
- ChTM, cholestyramine
- Cholesterol
- Cholestyramine
- DIO, diet-induced obesity
- ER, endoplasmic reticulum
- FC, free cholesterol
- Fatty Liver
- GSK3β, glycogen synthase kinase 3β
- HMGCR, HMG-CoA reductase
- LC3, microtubule-associated protein 1A/1B-light chain 3
- LDLR, low-density lipoprotein receptor
- LMP, lysosome membrane permeabilization
- Nuclear Receptor
- PI, phosphatidylinositol
- PM, plasma membrane
- S6, tibosomal protein S6
- SREBP, sterol response element binding protein
- mRNA, messenger RNA
- mTOR, the nutrient sensing mechanistic target of rapamycin
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Affiliation(s)
- Yifeng Wang
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Yifeng Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Jibiao Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Hemantkumar Chavan
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - David Matye
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Hong-Min Ni
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - John Y.L. Chiang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio
| | - Partha Krishnamurthy
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Tiangang Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas,Correspondence Address correspondence to: Tiangang Li, PhD, Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, Kansas 66160. fax: (913) 588-7501.Department of PharmacologyToxicology and TherapeuticsUniversity of Kansas Medical Center3901 Rainbow BoulevardKansas CityKansas 66160
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Pearson GL, Mellett N, Chu KY, Boslem E, Meikle PJ, Biden TJ. A comprehensive lipidomic screen of pancreatic β-cells using mass spectroscopy defines novel features of glucose-stimulated turnover of neutral lipids, sphingolipids and plasmalogens. Mol Metab 2016; 5:404-414. [PMID: 27257600 PMCID: PMC4877660 DOI: 10.1016/j.molmet.2016.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 01/05/2023] Open
Abstract
Objective Glucose promotes lipid remodelling in pancreatic β-cells, and this is thought to contribute to the regulation of insulin secretion, but the metabolic pathways and potential signalling intermediates have not been fully elaborated. Methods Using mass spectrometry (MS) we quantified changes in approximately 300 lipid metabolites in MIN6 β-cells and isolated mouse islets following 1 h stimulation with glucose. Flux through sphingolipid pathways was also assessed in 3H-sphinganine-labelled cells using TLC. Results Glucose specifically activates the conversion of triacylglycerol (TAG) to diacylglycerol (DAG). This leads indirectly to the formation of 18:1 monoacylglycerol (MAG), via degradation of saturated/monounsaturated DAG species, such as 16:0_18:1 DAG, which are the most abundant, immediate products of glucose-stimulated TAG hydrolysis. However, 16:0-containing, di-saturated DAG species are a better direct marker of TAG hydrolysis since, unlike the 18:1-containing DAGs, they are predominately formed via this route. Using multiple reaction monitoring, we confirmed that in islets under basal conditions, 18:1 MAG is the most abundant species. We further demonstrated a novel site of glucose to enhance the conversion of ceramide to sphingomyelin (SM) and galactosylceramide (GalCer). Flux and product:precursor analyses suggest regulation of the enzyme SM synthase, which would constitute a separate mechanism for localized generation of DAG in response to glucose. Phosphatidylcholine (PC) plasmalogen (P) species, specifically those containing 20:4, 22:5 and 22:6 side chains, were also diminished in the presence of glucose, whereas the more abundant phosphatidylethanolamine plasmalogens were unchanged. Conclusion Our results highlight 18:1 MAG, GalCer, PC(P) and DAG/SM as potential contributors to metabolic stimulus-secretion coupling. Using mass spectroscopy lipidomics we have defined new aspects of glucose simulated lipid turnover in pancreatic beta cells. Glucose directly stimulates triacylglycerol hydrolysis, of which di-saturated diacylglycerol species are excellent markers. C18:1 is the most abundant monacylglycerol, and the one most obviously increased by glucose. Phosphatidylcholine plasmalogens with poly-unsaturated side chains are preferentially decreased by glucose. Glucose specifically enhances the conversion of ceramide to both sphingomyelin and galactosylceramide.
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Key Words
- (O), ether lipid
- (P), plasmalogen
- ATGL, adipose tissue glycerolipase
- CE, cholesterol ester
- COH, free cholesterol
- Ceramide
- DAG, diacylglycerol
- Diacylglycerol
- FA, fatty acid
- GSIS, glucose-stimulated insulin secretion
- GalCer, galactosylceramide
- GluCer, glucosylceramide
- HSL, hormone sensitive lipase
- Insulin secretion
- KRHB, Krebs Ringer Hepes Buffer
- MAG, monacylglycerol
- MHC, monohexosylceramide
- MS, mass spectrometry
- Monacylglycerol
- PC, phosphatidylcholine
- PE, phosphatidylethanolamine
- PI, phosphatidylinositol
- PKD, protein kinase D
- PLA2, phospholipase A2
- Pancreatic β-cell
- Plasmalogen
- SM, sphingomyelin
- TAG, triacylglycerol
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Affiliation(s)
- Gemma L Pearson
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia
| | - Natalie Mellett
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Kwan Yi Chu
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia
| | - Ebru Boslem
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia
| | - Peter J Meikle
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
| | - Trevor J Biden
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW, 2010, Australia; St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Australia.
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