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Correa Y, Ravel M, Imbert M, Waldie S, Clifton L, Terry A, Roosen‐Runge F, Lagerstedt JO, Moir M, Darwish T, Cárdenas M, Del Giudice R. Lipid exchange of apolipoprotein A-I amyloidogenic variants in reconstituted high-density lipoprotein with artificial membranes. Protein Sci 2024; 33:e4987. [PMID: 38607188 PMCID: PMC11010956 DOI: 10.1002/pro.4987] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
High-density lipoproteins (HDLs) are responsible for removing cholesterol from arterial walls, through a process known as reverse cholesterol transport. The main protein in HDL, apolipoprotein A-I (ApoA-I), is essential to this process, and changes in its sequence significantly alter HDL structure and functions. ApoA-I amyloidogenic variants, associated with a particular hereditary degenerative disease, are particularly effective at facilitating cholesterol removal, thus protecting carriers from cardiovascular disease. Thus, it is conceivable that reconstituted HDL (rHDL) formulations containing ApoA-I proteins with functional/structural features similar to those of amyloidogenic variants hold potential as a promising therapeutic approach. Here we explored the effect of protein cargo and lipid composition on the function of rHDL containing one of the ApoA-I amyloidogenic variants G26R or L174S by Fourier transformed infrared spectroscopy and neutron reflectometry. Moreover, small-angle x-ray scattering uncovered the structural and functional differences between rHDL particles, which could help to comprehend higher cholesterol efflux activity and apparent lower phospholipid (PL) affinity. Our findings indicate distinct trends in lipid exchange (removal vs. deposition) capacities of various rHDL particles, with the rHDL containing the ApoA-I amyloidogenic variants showing a markedly lower ability to remove lipids from artificial membranes compared to the rHDL containing the native protein. This effect strongly depends on the level of PL unsaturation and on the particles' ultrastructure. The study highlights the importance of the protein cargo, along with lipid composition, in shaping rHDL structure, contributing to our understanding of lipid-protein interactions and their behavior.
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Affiliation(s)
- Yubexi Correa
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
| | - Mathilde Ravel
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
| | - Marie Imbert
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
| | - Sarah Waldie
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
| | - Luke Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities CouncilRutherford Appleton Laboratory, Harwell Science and Innovation CampusDidcotUK
| | - Ann Terry
- MAX IV LaboratoryCoSAXS Beamline, Lund UniversityLundSweden
| | - Felix Roosen‐Runge
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
| | - Jens O. Lagerstedt
- Islet Cell Exocytosis, Department of Clinical Sciences in Malmö, Lund University Diabetes CentreLund UniversityMalmöSweden
- Rare Endocrine Disorders, Research and Early DevelopmentNovo NordiskCopenhagenDenmark
| | - Michael Moir
- National Deuteration FacilityAustralian Nuclear Science and Technology Organization (ANSTO)Lucas HeightsNew South WalesAustralia
| | - Tamim Darwish
- National Deuteration FacilityAustralian Nuclear Science and Technology Organization (ANSTO)Lucas HeightsNew South WalesAustralia
- Faculty of Science and TechnologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Marité Cárdenas
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
- Ikerbasque, Basque Foundation for ScienceBilbaoSpain
- Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC))LeioaSpain
| | - Rita Del Giudice
- Biofilm – Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and SocietyMalmö UniversityMalmöSweden
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2
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Miskelly MG, Lindqvist A, Piccinin E, Hamilton A, Cowan E, Nergård BJ, Del Giudice R, Ngara M, Cataldo LR, Kryvokhyzha D, Volkov P, Engelking L, Artner I, Lagerstedt JO, Eliasson L, Ahlqvist E, Moschetta A, Hedenbro J, Wierup N. RNA sequencing unravels novel L cell constituents and mechanisms of GLP-1 secretion in human gastric bypass-operated intestine. Diabetologia 2024; 67:356-370. [PMID: 38032369 PMCID: PMC10789678 DOI: 10.1007/s00125-023-06046-8] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/15/2023] [Indexed: 12/01/2023]
Abstract
AIMS/HYPOTHESIS Roux-en-Y gastric bypass surgery (RYGB) frequently results in remission of type 2 diabetes as well as exaggerated secretion of glucagon-like peptide-1 (GLP-1). Here, we assessed RYGB-induced transcriptomic alterations in the small intestine and investigated how they were related to the regulation of GLP-1 production and secretion in vitro and in vivo. METHODS Human jejunal samples taken perisurgically and 1 year post RYGB (n=13) were analysed by RNA-seq. Guided by bioinformatics analysis we targeted four genes involved in cholesterol biosynthesis, which we confirmed to be expressed in human L cells, for potential involvement in GLP-1 regulation using siRNAs in GLUTag and STC-1 cells. Gene expression analyses, GLP-1 secretion measurements, intracellular calcium imaging and RNA-seq were performed in vitro. OGTTs were performed in C57BL/6j and iScd1-/- mice and immunohistochemistry and gene expression analyses were performed ex vivo. RESULTS Gene Ontology (GO) analysis identified cholesterol biosynthesis as being most affected by RYGB. Silencing or chemical inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme in the synthesis of monounsaturated fatty acids, was found to reduce Gcg expression and secretion of GLP-1 by GLUTag and STC-1 cells. Scd1 knockdown also reduced intracellular Ca2+ signalling and membrane depolarisation. Furthermore, Scd1 mRNA expression was found to be regulated by NEFAs but not glucose. RNA-seq of SCD1 inhibitor-treated GLUTag cells identified altered expression of genes implicated in ATP generation and glycolysis. Finally, gene expression and immunohistochemical analysis of the jejunum of the intestine-specific Scd1 knockout mouse model, iScd1-/-, revealed a twofold higher L cell density and a twofold increase in Gcg mRNA expression. CONCLUSIONS/INTERPRETATION RYGB caused robust alterations in the jejunal transcriptome, with genes involved in cholesterol biosynthesis being most affected. Our data highlight SCD as an RYGB-regulated L cell constituent that regulates the production and secretion of GLP-1.
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Affiliation(s)
- Michael G Miskelly
- Neuroendocrine Cell Biology, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Andreas Lindqvist
- Neuroendocrine Cell Biology, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Elena Piccinin
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
- Department of Interdisciplinary Medicine, University of Bari 'Aldo Moro', Bari, Italy
| | - Alexander Hamilton
- Molecular Metabolism, Lund University Diabetes Centre, Lund University, Malmö, Sweden
- Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Elaine Cowan
- Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | | | - Rita Del Giudice
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Mtakai Ngara
- Neuroendocrine Cell Biology, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Luis R Cataldo
- Molecular Metabolism, Lund University Diabetes Centre, Lund University, Malmö, Sweden
- Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dmytro Kryvokhyzha
- Bioinformatics Unit, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Petr Volkov
- Bioinformatics Unit, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Luke Engelking
- Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Isabella Artner
- Endocrine Cell Differentiation and Function, Stem Cell Centre, Lund University, Malmö, Sweden
| | - Jens O Lagerstedt
- Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Lena Eliasson
- Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Emma Ahlqvist
- Genomics, Diabetes and Endocrinology, Lund University Diabetes Centre, Lund University, Malmö, Sweden
| | - Antonio Moschetta
- Department of Interdisciplinary Medicine, University of Bari 'Aldo Moro', Bari, Italy
- INBB National Institute for Biostructure and Biosystems, Rome, Italy
| | - Jan Hedenbro
- Department of Surgery, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Nils Wierup
- Neuroendocrine Cell Biology, Lund University Diabetes Centre, Lund University, Malmö, Sweden.
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3
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Cronjé HT, Karhunen V, Hovingh GK, Coppieters K, Lagerstedt JO, Nyberg M, Gill D. Genetic evidence implicating natriuretic peptide receptor-3 in cardiovascular disease risk: a Mendelian randomization study. BMC Med 2023; 21:158. [PMID: 37101178 PMCID: PMC10134514 DOI: 10.1186/s12916-023-02867-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023] Open
Abstract
BACKGROUND C-type natriuretic peptide (CNP) is a known target for promoting growth and has been implicated as a therapeutic opportunity for the prevention and treatment of cardiovascular disease (CVD). This study aimed to explore the effect of CNP on CVD risk using the Mendelian randomization (MR) framework. METHODS Instrumental variables mimicking the effects of pharmacological intervention on CNP were identified as uncorrelated genetic variants located in the genes coding for its primary receptors, natriuretic peptide receptors-2 and 3 (NPR2 and NPR3), that associated with height. We performed MR and colocalization analyses to investigate the effects of NPR2 signalling and NPR3 function on CVD outcomes and risk factors. MR estimates were compared to those obtained when considering height variants from throughout the genome. RESULTS Genetically-proxied reduced NPR3 function was associated with a lower risk of CVD, with odds ratio (OR) 0.74 per standard deviation (SD) higher NPR3-predicted height, and 95% confidence interval (95% CI) 0.64-0.86. This effect was greater in magnitude than observed when considering height variants from throughout the genome. For CVD subtypes, similar MR associations for NPR3-predicted height were observed when considering the outcomes of coronary artery disease (0.75, 95% CI 0.60-0.92), stroke (0.69, 95% CI 0.50-0.95) and heart failure (0.77, 95% CI 0.58-1.02). Consideration of CVD risk factors identified systolic blood pressure (SBP) as a potential mediator of the NPR3-related CVD risk lowering. For stroke, we found that the MR estimate for NPR3 was greater in magnitude than could be explained by a genetically predicted SBP effect alone. Colocalization results largely supported the MR findings, with no evidence of results being driven by effects due to variants in linkage disequilibrium. There was no MR evidence supporting effects of NPR2 on CVD risk, although this null finding could be attributable to fewer genetic variants being identified to instrument this target. CONCLUSIONS This genetic analysis supports the cardioprotective effects of pharmacologically inhibiting NPR3 receptor function, which is only partly mediated by an effect on blood pressure. There was unlikely sufficient statistical power to investigate the cardioprotective effects of NPR2 signalling.
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Affiliation(s)
- Héléne T Cronjé
- Department of Public Health, Section of Epidemiology, University of Copenhagen, Copenhagen, Denmark.
| | - Ville Karhunen
- Faculty of Science, Research Unit of Mathematical Sciences, University of Oulu, Oulu, Finland
- Research Unit of Population Health, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - G Kees Hovingh
- Department of Vascular Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- Global Chief Medical Office, Novo Nordisk, Copenhagen, Denmark
| | - Ken Coppieters
- Global Project Management, Global Drug Discovery, Novo Nordisk, Copenhagen, Denmark
| | - Jens O Lagerstedt
- Rare Endocrine Disorders, Research and Early Development, Novo Nordisk, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, 221 84, Lund, Sweden
| | - Michael Nyberg
- Vascular Biology, Research and Early Development, Novo Nordisk, Maaloev, Denmark
| | - Dipender Gill
- Chief Scientific Advisor Office, Research and Early Development, Novo Nordisk, Copenhagen, Denmark.
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
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Bacos K, Perfilyev A, Karagiannopoulos A, Cowan E, Ofori JK, Bertonnier-Brouty L, Rönn T, Lindqvist A, Luan C, Ruhrmann S, Ngara M, Nilsson Å, Gheibi S, Lyons CL, Lagerstedt JO, Barghouth M, Esguerra JL, Volkov P, Fex M, Mulder H, Wierup N, Krus U, Artner I, Eliasson L, Prasad RB, Cataldo LR, Ling C. Type 2 diabetes candidate genes, including PAX5, cause impaired insulin secretion in human pancreatic islets. J Clin Invest 2023; 133:163612. [PMID: 36656641 PMCID: PMC9927941 DOI: 10.1172/jci163612] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [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: 07/15/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
Type 2 diabetes (T2D) is caused by insufficient insulin secretion from pancreatic β cells. To identify candidate genes contributing to T2D pathophysiology, we studied human pancreatic islets from approximately 300 individuals. We found 395 differentially expressed genes (DEGs) in islets from individuals with T2D, including, to our knowledge, novel (OPRD1, PAX5, TET1) and previously identified (CHL1, GLRA1, IAPP) candidates. A third of the identified expression changes in islets may predispose to diabetes, as expression of these genes associated with HbA1c in individuals not previously diagnosed with T2D. Most DEGs were expressed in human β cells, based on single-cell RNA-Seq data. Additionally, DEGs displayed alterations in open chromatin and associated with T2D SNPs. Mouse KO strains demonstrated that the identified T2D-associated candidate genes regulate glucose homeostasis and body composition in vivo. Functional validation showed that mimicking T2D-associated changes for OPRD1, PAX5, and SLC2A2 impaired insulin secretion. Impairments in Pax5-overexpressing β cells were due to severe mitochondrial dysfunction. Finally, we discovered PAX5 as a potential transcriptional regulator of many T2D-associated DEGs in human islets. Overall, we have identified molecular alterations in human pancreatic islets that contribute to β cell dysfunction in T2D pathophysiology.
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Affiliation(s)
- Karl Bacos
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | | | - Alexandros Karagiannopoulos
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Elaine Cowan
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Jones K. Ofori
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Ludivine Bertonnier-Brouty
- Endocrine Cell Differentiation, Department of Laboratory Medicine, Lund Stem Cell Center, Malmö, Scania, Sweden
| | - Tina Rönn
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Andreas Lindqvist
- Neuroendocrine Cell Biology, Department of Experimental Medical Science
| | - Cheng Luan
- Unit of Islet Pathophysiology, Department of Clinical Sciences
| | - Sabrina Ruhrmann
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Mtakai Ngara
- Neuroendocrine Cell Biology, Department of Experimental Medical Science
| | - Åsa Nilsson
- Human Tissue Lab, Department of Clinical Sciences
| | - Sevda Gheibi
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Claire L. Lyons
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Jens O. Lagerstedt
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | | | - Jonathan L.S. Esguerra
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Petr Volkov
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Malin Fex
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Hindrik Mulder
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Nils Wierup
- Neuroendocrine Cell Biology, Department of Experimental Medical Science
| | - Ulrika Krus
- Human Tissue Lab, Department of Clinical Sciences
| | - Isabella Artner
- Endocrine Cell Differentiation, Department of Laboratory Medicine, Lund Stem Cell Center, Malmö, Scania, Sweden
| | - Lena Eliasson
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Rashmi B. Prasad
- Genomics, Diabetes and Endocrinology, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden.,Institute of Molecular Medicine (FIMM), Helsinki University, Helsinki, Finland
| | - Luis Rodrigo Cataldo
- Molecular Metabolism Unit, Department of Clinical Sciences, and,The Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Ling
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
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5
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Nilsson O, Lindvall M, Obici L, Ekström S, Lagerstedt JO, Del Giudice R. Structure dynamics of ApoA-I amyloidogenic variants in small HDL increase their ability to mediate cholesterol efflux. J Lipid Res 2020; 62:100004. [PMID: 33410751 PMCID: PMC7890215 DOI: 10.1194/jlr.ra120000920] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 11/04/2020] [Accepted: 11/17/2020] [Indexed: 01/17/2023] Open
Abstract
Apolipoprotein A-I (ApoA-I) of high density lipoproteins (HDLs) is essential for the transportation of cholesterol between peripheral tissues and the liver. However, specific mutations in ApoA-I of HDLs are responsible for a late-onset systemic amyloidosis, the pathological accumulation of protein fibrils in tissues and organs. Carriers of these mutations do not exhibit increased cardiovascular disease risk despite displaying reduced levels of ApoA-I/HDL cholesterol. To explain this paradox, we show that the HDL particle profiles of patients carrying either L75P or L174S ApoA-I amyloidogenic variants show a higher relative abundance of the 8.4-nm versus 9.6-nm particles and that serum from patients, as well as reconstituted 8.4- and 9.6-nm HDL particles (rHDL), possess increased capacity to catalyze cholesterol efflux from macrophages. Synchrotron radiation circular dichroism and hydrogen-deuterium exchange revealed that the variants in 8.4-nm rHDL have altered secondary structure composition and display a more flexible binding to lipids than their native counterpart. The reduced HDL cholesterol levels of patients carrying ApoA-I amyloidogenic variants are thus balanced by higher proportion of small, dense HDL particles, and better cholesterol efflux due to altered, region-specific protein structure dynamics.
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Affiliation(s)
- Oktawia Nilsson
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Mikaela Lindvall
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Laura Obici
- Amyloidosis Research & Treatment Centre, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Simon Ekström
- BioMS - Swedish National Infrastructure for Biological Mass Spectrometry, Lund University, Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden; Lund Institute of Advanced Neutron and X-ray Science (LINXS), Lund, Sweden.
| | - Rita Del Giudice
- Department of Experimental Medical Science, Lund University, Lund, Sweden.
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6
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Edmunds SJ, Liébana-García R, Stenkula KG, Lagerstedt JO. A short peptide of the C-terminal class Y helices of apolipoprotein A-I has preserved functions in cholesterol efflux and in vivo metabolic control. Sci Rep 2020; 10:18070. [PMID: 33093642 PMCID: PMC7582918 DOI: 10.1038/s41598-020-75232-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 03/30/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022] Open
Abstract
Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) induces glucose uptake by muscle tissues and stimulates pancreatic insulin secretion, and also facilitates cholesterol transport in circulation, and is explored for anti-diabetic and anti-atherosclerotic treatments. As the better alternative to complex protein-lipid formulations it was recently established that the C-terminal region of the ApoA-I protein singly improves the metabolic control and prevents formation of atherosclerotic plaques. Additional investigations of peptides based on the ApoA-I structure may lead to novel anti-diabetic drugs. We here investigate a short peptide (33mer, RG33) that corresponds to the two last helical segments (aa 209-241) of the ApoA-I structure (so-called class Y-helices which forms amphipathic helices) for stability and solubility in serum, for in vitro cholesterol efflux capability, and for providing in vivo glucose control in an insulin resistant mouse model. The RG33 peptide efficiently solubilizes lipid-vesicles, and promotes the efflux of cholesterol from cultured macrophages. The efflux capacity is significantly increased in the presence of lipids compared to non-lipidated RG33. Finally, acute treatment with the RG33 peptide significantly improves the glucose clearance capacity of insulin resistant mice. The impact of the RG33 peptide on glucose control and cholesterol transport, as well as the physicochemical properties, makes it a good candidate for translational exploration of its therapeutic potential in diabetes treatment.
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Affiliation(s)
- Shelley J Edmunds
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden
| | - Rebeca Liébana-García
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden
| | - Karin G Stenkula
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden
| | - Jens O Lagerstedt
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden. .,Lund Institute of Advanced Neutron and X-ray Science (LINXS), Lund, Sweden.
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7
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Fritzen AM, Domingo-Espín J, Lundsgaard AM, Kleinert M, Israelsen I, Carl CS, Nicolaisen TS, Kjøbsted R, Jeppesen JF, Wojtaszewski JFP, Lagerstedt JO, Kiens B. ApoA-1 improves glucose tolerance by increasing glucose uptake into heart and skeletal muscle independently of AMPKα 2. Mol Metab 2020; 35:100949. [PMID: 32244181 PMCID: PMC7082546 DOI: 10.1016/j.molmet.2020.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [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: 10/02/2019] [Revised: 01/03/2020] [Accepted: 01/24/2020] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE Acute administration of the main protein component of high-density lipoprotein, apolipoprotein A-I (ApoA-1), improves glucose uptake in skeletal muscle. The molecular mechanisms mediating this are not known, but in muscle cell cultures, ApoA-1 failed to increase glucose uptake when infected with a dominant-negative AMP-activated protein kinase (AMPK) virus. We therefore investigated whether AMPK is necessary for ApoA-1-stimulated glucose uptake in intact heart and skeletal muscle in vivo. METHODS The effect of injection with recombinant human ApoA-1 (rApoA-1) on glucose tolerance, glucose-stimulated insulin secretion, and glucose uptake into skeletal and heart muscle with and without block of insulin secretion by injection of epinephrine (0.1 mg/kg) and propranolol (5 mg/kg), were investigated in 8 weeks high-fat diet-fed (60E%) wild-type and AMPKα2 kinase-dead mice in the overnight-fasted state. In addition, the effect of rApoA-1 on glucose uptake in isolated skeletal muscle ex vivo was studied. RESULTS rApoA-1 lowered plasma glucose concentration by 1.7 mmol/l within 3 h (6.1 vs 4.4 mmol/l; p < 0.001). Three hours after rApoA-1 injection, glucose tolerance during a 40-min glucose tolerance test (GTT) was improved compared to control (area under the curve (AUC) reduced by 45%, p < 0.001). This was accompanied by an increased glucose clearance into skeletal (+110%; p < 0.001) and heart muscle (+100%; p < 0.001) and an increase in glucose-stimulated insulin secretion 20 min after glucose injection (+180%; p < 0.001). When insulin secretion was blocked during a GTT, rApoA-1 still enhanced glucose tolerance (AUC lowered by 20% compared to control; p < 0.001) and increased glucose clearance into skeletal (+50%; p < 0.05) and heart muscle (+270%; p < 0.001). These improvements occurred to a similar extent in both wild-type and AMPKα2 kinase-dead mice and thus independently of AMPKα2 activity in skeletal- and heart muscle. Interestingly, rApoA-1 failed to increase glucose uptake in isolated skeletal muscles ex vivo. CONCLUSIONS In conclusion, ApoA-1 stimulates in vivo glucose disposal into skeletal and heart muscle independently of AMPKα2. The observation that ApoA-1 fails to increase glucose uptake in isolated muscle ex vivo suggests that additional systemic effects are required.
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Affiliation(s)
- Andreas Mæchel Fritzen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, S-221 84, Lund, Sweden
| | - Anne-Marie Lundsgaard
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Maximilian Kleinert
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Germany
| | - Ida Israelsen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Christian S Carl
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Trine S Nicolaisen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84, Lund, Sweden; Lund Institute of Advanced X-ray and Neutron Science (LINXS), Lund, Sweden.
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
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8
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Dwivedi OP, Lehtovirta M, Hastoy B, Chandra V, Krentz NAJ, Kleiner S, Jain D, Richard AM, Abaitua F, Beer NL, Grotz A, Prasad RB, Hansson O, Ahlqvist E, Krus U, Artner I, Suoranta A, Gomez D, Baras A, Champon B, Payne AJ, Moralli D, Thomsen SK, Kramer P, Spiliotis I, Ramracheya R, Chabosseau P, Theodoulou A, Cheung R, van de Bunt M, Flannick J, Trombetta M, Bonora E, Wolheim CB, Sarelin L, Bonadonna RC, Rorsman P, Davies B, Brosnan J, McCarthy MI, Otonkoski T, Lagerstedt JO, Rutter GA, Gromada J, Gloyn AL, Tuomi T, Groop L. Loss of ZnT8 function protects against diabetes by enhanced insulin secretion. Nat Genet 2019; 51:1596-1606. [PMID: 31676859 PMCID: PMC6858874 DOI: 10.1038/s41588-019-0513-9] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [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] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 09/13/2019] [Indexed: 12/30/2022]
Abstract
A rare loss-of-function allele p.Arg138* in SLC30A8 encoding the zinc transporter 8 (ZnT8), which is enriched in Western Finland, protects against type 2 diabetes (T2D). We recruited relatives of the identified carriers and showed that protection was associated with better insulin secretion due to enhanced glucose responsiveness and proinsulin conversion, particularly when compared with individuals matched for the genotype of a common T2D-risk allele in SLC30A8, p.Arg325. In genome-edited human induced pluripotent stem cell (iPSC)-derived β-like cells, we establish that the p.Arg138* allele results in reduced SLC30A8 expression due to haploinsufficiency. In human β cells, loss of SLC30A8 leads to increased glucose responsiveness and reduced KATP channel function similar to isolated islets from carriers of the T2D-protective allele p.Trp325. These data position ZnT8 as an appealing target for treatment aimed at maintaining insulin secretion capacity in T2D.
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Affiliation(s)
- Om Prakash Dwivedi
- Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland
| | - Mikko Lehtovirta
- Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland
| | - Benoit Hastoy
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Vikash Chandra
- Stem Cells and Metabolism Research Program and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Nicole A J Krentz
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Deepak Jain
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Fernando Abaitua
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Nicola L Beer
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Antje Grotz
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Rashmi B Prasad
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Ola Hansson
- Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Emma Ahlqvist
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Ulrika Krus
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Isabella Artner
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Anu Suoranta
- Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland
| | | | - Aris Baras
- Regeneron Pharmaceuticals, Tarrytown, NY, USA
| | - Benoite Champon
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Anthony J Payne
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Daniela Moralli
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Soren K Thomsen
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Philipp Kramer
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Ioannis Spiliotis
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Reshma Ramracheya
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Pauline Chabosseau
- Section of Cell Biology, Department of Medicine, Imperial College London, Imperial Centre for Translational and Experimental Medicine, Hammersmith, Hospital, London, UK
| | - Andria Theodoulou
- Section of Cell Biology, Department of Medicine, Imperial College London, Imperial Centre for Translational and Experimental Medicine, Hammersmith, Hospital, London, UK
| | - Rebecca Cheung
- Section of Cell Biology, Department of Medicine, Imperial College London, Imperial Centre for Translational and Experimental Medicine, Hammersmith, Hospital, London, UK
| | - Martijn van de Bunt
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Jason Flannick
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Maddalena Trombetta
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy
| | - Enzo Bonora
- Department of Medicine, University of Verona and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy
| | - Claes B Wolheim
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
| | | | - Riccardo C Bonadonna
- Department of Medicine and Surgery, University of Parma School of Medicine and Azienda Ospedaliera Universitaria of Parma, Parma, Italy
| | - Patrik Rorsman
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Benjamin Davies
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Mark I McCarthy
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Timo Otonkoski
- Stem Cells and Metabolism Research Program and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Guy A Rutter
- Section of Cell Biology, Department of Medicine, Imperial College London, Imperial Centre for Translational and Experimental Medicine, Hammersmith, Hospital, London, UK
| | | | - Anna L Gloyn
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, UK
| | - Tiinamaija Tuomi
- Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland
- Folkhälsan Research Center, Helsinki, Finland
- Abdominal Center, Endocrinology, Helsinki University Central Hospital, Research Program for Clinical and Molecular Metabolism, University of Helsinki, Helsinki, Finland
| | - Leif Groop
- Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland.
- Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden.
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9
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Edmunds SJ, Liébana-García R, Nilsson O, Domingo-Espín J, Grönberg C, Stenkula KG, Lagerstedt JO. ApoAI-derived peptide increases glucose tolerance and prevents formation of atherosclerosis in mice. Diabetologia 2019; 62:1257-1267. [PMID: 31069401 PMCID: PMC6560211 DOI: 10.1007/s00125-019-4877-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [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: 09/18/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023]
Abstract
AIMS/HYPOTHESIS Finding new treatment alternatives for individuals with diabetes with severe insulin resistance is highly desired. To identify novel mechanisms that improve glucose uptake in skeletal muscle, independently from insulin levels and signalling, we have explored the therapeutic potential of a short peptide sequence, RG54, derived from apolipoprotein A-I (ApoA-I). METHODS INS-1E rat clonal beta cells, C2C12 rat muscle myotubes and J774 mouse macrophages were used to study the impact of RG54 peptide on glucose-stimulated insulin secretion, glucose uptake and cholesterol efflux, respectively. GTTs were carried out on diet-induced insulin-resistant and Leprdb diabetic mouse models treated with RG54 peptide, and the impact of RG54 peptide on atherosclerosis was evaluated in Apoe-/- mice. Control mice received ApoA-I protein, liraglutide or NaCl. RESULTS The synthetic RG54 peptide induced glucose uptake in cultured muscle myotubes by a similar amount as insulin, and also primed pancreatic beta cells for improved glucose-stimulated insulin secretion. The findings were verified in diet-induced insulin-resistant and Leprdb diabetic mice, jointly confirming the physiological effect. The RG54 peptide also efficiently catalysed cholesterol efflux from macrophages and prevented the formation of atherosclerotic plaques in Apoe-/- mice. CONCLUSIONS/INTERPRETATION The RG54 peptide exhibits good prospects for providing glucose control and reducing the risk of cardiovascular disease in individuals with severe insulin resistance.
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Affiliation(s)
- Shelley J Edmunds
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Rebeca Liébana-García
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Oktawia Nilsson
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Caitriona Grönberg
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden.
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10
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Azhar S, Bittner S, Hu J, Shen WJ, Cortez Y, Hao X, Han L, Lagerstedt JO, Kraemer FB, Johansson JO. Novel ABCA1 peptide agonists with antidiabetic action. Mol Cell Endocrinol 2019; 480:1-11. [PMID: 30290217 PMCID: PMC6626528 DOI: 10.1016/j.mce.2018.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/19/2018] [Accepted: 09/30/2018] [Indexed: 12/26/2022]
Abstract
Previously, apoE-derived ABCA1 agonist peptides have been shown to possess anti-atherosclerotic and possibly antidiabetic properties. Here we assessed the in vitro and in vivo actions of a second generation of ABCA1 peptide agonists, CS6253 and T6991-2, on glucose homeostasis. The results show that these two peptides improve glucose tolerance in a prediabetic diet-induced obesity mouse model by enhancing insulin secretion. It was further demonstrated that T6991-2 also improved glucose tolerance in leptin-deficient (ob/ob) mice. CS6253 increased insulin secretion both under basal conditions and in response to high glucose stimulation in pancreatic INS-1 β-cells rendered leptin receptor deficient with specific siRNA. Additional in vitro cell studies suggest that the CS6253 agonist attenuates hepatic gluconeogenesis and glucose transport. It also potentiates insulin-stimulated glucose uptake and utilization. These observed anti-diabetic actions suggest additional benefits of the CS6253 and T6991-2 ABCA1 peptide agonists for cardiovascular disease beyond their direct anti-atherosclerosis properties previously described.
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Affiliation(s)
- Salman Azhar
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA; Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Stefanie Bittner
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA
| | - Jie Hu
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA; PCET Division, Aragen Bioscience, 260, Chocrane Circle, Morgan Hill, CA, 94307, USA
| | - Wen-Jun Shen
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA; Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Yuan Cortez
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA
| | - Xiao Hao
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA; Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, CA, 94305, USA; Department of Endocrinology, The First Affiliated Hospital of the Medical College of Zhengzhou University, Zhengzhou, China
| | - Lu Han
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA
| | - Jens O Lagerstedt
- Department of Experimental Medical Research, Biomedical Center Floor C13, Tornavagen 10, Lund University, S-221 84, Lund, Sweden
| | - Fredric B Kraemer
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, CA, 94304, USA; Division of Endocrinology, Gerontology and Metabolism, Stanford University School of Medicine, Stanford, CA, 94305, USA
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11
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Lagerstedt JO, Dalla-Riva J, Marinkovic G, Del Giudice R, Engelbertsen D, Burlin J, Petrlova J, Lindahl M, Bernfur K, Melander O, Nilsson J, Schiopu A. Anti-ApoA-I IgG antibodies are not associated with carotid artery disease progression and first-time cardiovascular events in middle-aged individuals. J Intern Med 2019; 285:49-58. [PMID: 30028049 DOI: 10.1111/joim.12817] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [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] [Indexed: 12/22/2022]
Abstract
OBJECTIVE IgG antibodies against apolipoprotein A-I (ApoA-I) have been found to be elevated in subjects from the general population with clinically manifest cardiovascular disease and in myocardial infarction patients with an adverse prognosis. Here, we investigated whether these antibodies are prospectively associated with carotid artery disease progression and with the risk for first-time cardiovascular events in individuals with no previous history of cardiovascular disease. APPROACH AND RESULTS We selected 383 subjects from the cardiovascular cohort of Malmö Diet and Cancer study who suffered a coronary event during a median follow-up period of 15.4 (10.3-16.4) years and 395 age- and sex-matched controls. None of the study participants had a previous history of coronary artery disease or stroke. Anti-ApoA-I IgG were measured by ELISA in serum samples collected at baseline. Intima-media thickness (IMT) was measured in the common carotid artery and in the carotid bifurcation at baseline and after 15.9 (±1.5) years. We found no associations between anti-ApoA-I IgG and carotid artery IMT at baseline or with IMT progression during follow-up. In Cox proportional hazards analyses adjusted for traditional cardiovascular risk factors, the hazard ratio (HR 95%CI) for the primary outcome, incident coronary events, was 0.97 (0.75-1.25), P = 0.782, in subjects with anti-ApoA-I IgG within the highest tertile compared with the lowest tertile. Similarly, we did not find any associations with the secondary outcome, incident first-time stroke. CONCLUSIONS Serum autoantibodies against ApoA-I do not correlate with disease progression and adverse events in cardiovascular disease-free individuals from the general population.
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Affiliation(s)
- J O Lagerstedt
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - J Dalla-Riva
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - G Marinkovic
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - R Del Giudice
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - D Engelbertsen
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - J Burlin
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - J Petrlova
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - M Lindahl
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - K Bernfur
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - O Melander
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - J Nilsson
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - A Schiopu
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden.,Department of Cardiology, Skåne University Hospital Malmö, Malmö, Sweden
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12
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Del Giudice R, Lagerstedt JO. High-efficient bacterial production of human ApoA-I amyloidogenic variants. Protein Sci 2018; 27:2101-2109. [PMID: 30291643 PMCID: PMC6237697 DOI: 10.1002/pro.3522] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 12/17/2022]
Abstract
Apolipoprotein A-I (ApoA-I)-related amyloidosis is a rare disease caused by missense mutations in the APOA1 gene. These mutations lead to protein aggregation and abnormal accumulation of ApoA-I amyloid fibrils in heart, liver, kidneys, skin, nerves, ovaries, or testes. Consequently, the carriers are at risk of single- or multi-organ failure and of need of organ transplantation. Understanding the basic molecular structure and function of ApoA-I amyloidogenic variants, as well as their biological effects, is, therefore, of great interest. However, the intrinsic low stability of this type of proteins makes their overexpression and purification difficult. To overcome this barrier, we here describe an optimized production and purification procedure for human ApoA-I amyloidogenic proteins that efficiently provides between 46 mg and 91 mg (depending on the protein variant) of pure protein per liter of Escherichia coli culture. Structural integrity of the amyloidogenic and native ApoA-I proteins were verified by circular dichroism spectroscopy and intrinsic fluorescence analysis, and preserved functionality was demonstrated by use of a lipid clearance assay as well as by reconstitution of high-density lipoprotein (HDL) particles. In conclusion, the use of the described high-yield protein production system to obtain amyloidogenic ApoA-I proteins, and their native counterpart, will enable molecular and cellular experimental studies aimed to explain the molecular basis for this rare disease.
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Affiliation(s)
- Rita Del Giudice
- Department of Experimental Medical ScienceLund UniversityS‐221 84LundSweden
| | - Jens O. Lagerstedt
- Department of Experimental Medical ScienceLund UniversityS‐221 84LundSweden
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13
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Domingo-Espín J, Nilsson O, Bernfur K, Del Giudice R, Lagerstedt JO. Site-specific glycations of apolipoprotein A-I lead to differentiated functional effects on lipid-binding and on glucose metabolism. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2822-2834. [PMID: 29802959 DOI: 10.1016/j.bbadis.2018.05.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [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: 12/13/2017] [Revised: 05/17/2018] [Accepted: 05/22/2018] [Indexed: 02/06/2023]
Abstract
Prolonged hyperglycemia in poorly controlled diabetes leads to an increase in reactive glucose metabolites that covalently modify proteins by non-enzymatic glycation reactions. Apolipoprotein A-I (apoA-I) of high-density lipoprotein (HDL) is one of the proteins that becomes glycated in hyperglycemia. The impact of glycation on apoA-I protein structure and function in lipid and glucose metabolism were investigated. ApoA-I was chemically glycated by two different glucose metabolites (methylglyoxal and glycolaldehyde). Synchrotron radiation and conventional circular dichroism spectroscopy were used to study apoA-I structure and stability. The ability to bind lipids was measured by lipid-clearance assay and native gel analysis, and cholesterol efflux was measured by using lipid-laden J774 macrophages. Diet induced obese mice with established insulin resistance, L6 rat and C2C12 mouse myocytes, as well as INS-1E rat insulinoma cells, were used to determine in vivo and in vitro glucose uptake and insulin secretion. Site-specific, covalent modifications of apoA-I (lysines or arginines) led to altered protein structure, reduced lipid binding capability and a reduced ability to catalyze cholesterol efflux from macrophages, partly in a modification-specific manner. The stimulatory effects of apoA-I on the in vivo glucose clearance were negatively affected when apoA-I was modified with methylglyoxal, but not with glycolaldehyde. The in vitro data showed that both glucose uptake in muscle cells and insulin secretion from beta cells were affected. Taken together, glycation modifications impair the apoA-I protein functionality in lipid and glucose metabolism, which is expected to have implications for diabetes patients with poorly controlled blood glucose.
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Affiliation(s)
- Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Oktawia Nilsson
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Katja Bernfur
- Department of Biochemistry and Structural Biology, Lund University, S-221 84 Lund, Sweden
| | - Rita Del Giudice
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden.
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14
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Björkbacka H, Yao Mattisson I, Wigren M, Melander O, Fredrikson GN, Bengtsson E, Gonçalves I, Almgren P, Lagerstedt JO, Orho-Melander M, Engström G, Nilsson J. Plasma stem cell factor levels are associated with risk of cardiovascular disease and death. J Intern Med 2017; 282:508-521. [PMID: 28842933 DOI: 10.1111/joim.12675] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [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] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Stem cell factor (SCF) is a key growth factor for several types of stem and progenitor cells. There is experimental evidence that such cells are of importance for maintaining the integrity of the cardiovascular system. We investigated the association between circulating levels of SCF and risk for development of cardiovascular events and death. METHODS SCF was analysed by the proximity extension assay technique in plasma from 4742 subjects participating in the Malmö Diet and Cancer Study. Cardiovascular events and death were monitored through national registers with a mean follow-up time of 19.2 years. RESULTS Subjects with high baseline levels of SCF had lower cardiovascular (n = 340) and all-cause mortality (n = 1159) as well as a lower risk of heart failure (n = 177), stroke (n = 318) and myocardial infarction (n = 452). Smoking, diabetes and high alcohol consumption were associated with lower levels of SCF. Single nucleotide polymorphisms in the gene region encoding PDX1 C-terminal inhibiting factor 1 (PCIF1) and matrix metalloproteinase-9 were associated with plasma SCF levels. The highest SCF quartile remained independently associated with a lower risk of a lower risk of cardiovascular [hazard ratio and 95% confidence interval 0.59 (0.43-0.81)] and all-cause mortality [0.68 (0.57-0.81)], heart failure [0.50 (0.31-0.80)] and stroke [0.66 (0.47-0.92)], but not with MI [0.96 (0.72-1.27)] as compared with the lowest quartile when adjusting for traditional cardiovascular risk factors in Cox proportional hazard regression models. CONCLUSIONS This prospective population-based study demonstrates that subjects with high levels of SCF have a lower risk of cardiovascular events and death. The findings provide clinical support for a protective role of SCF in maintaining cardiovascular integrity.
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Affiliation(s)
- H Björkbacka
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - I Yao Mattisson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - M Wigren
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - O Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - G N Fredrikson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - E Bengtsson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - I Gonçalves
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden.,Department of Cardiology - Coronary diseases, Skåne University Hospital, Malmö, Sweden
| | - P Almgren
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - J O Lagerstedt
- Department of Experimental Medical Science, Lund University, Malmö, Sweden
| | - M Orho-Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - G Engström
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - J Nilsson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
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15
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Zhu L, Petrlova J, Gysbers P, Hebert H, Wallin S, Jegerschöld C, Lagerstedt JO. Structures of apolipoprotein A-I in high density lipoprotein generated by electron microscopy and biased simulations. Biochim Biophys Acta Gen Subj 2017; 1861:2726-2738. [DOI: 10.1016/j.bbagen.2017.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/18/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
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16
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Del Giudice R, Domingo-Espín J, Iacobucci I, Nilsson O, Monti M, Monti DM, Lagerstedt JO. Structural determinants in ApoA-I amyloidogenic variants explain improved cholesterol metabolism despite low HDL levels. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3038-3048. [PMID: 28887204 DOI: 10.1016/j.bbadis.2017.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 06/01/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022]
Abstract
Twenty Apolipoprotein A-I (ApoA-I) variants are responsible for a systemic hereditary amyloidosis in which protein fibrils can accumulate in different organs, leading to their failure. Several ApoA-I amyloidogenic mutations are also associated with hypoalphalipoproteinemia, low ApoA-I and high-density lipoprotein (HDL)-cholesterol plasma levels; however, subjects affected by ApoA-I-related amyloidosis do not show a higher risk of cardiovascular diseases (CVD). The structural features, the lipid binding properties and the functionality of four ApoA-I amyloidogenic variants were therefore inspected in order to clarify the paradox observed in the clinical phenotype of the affected subjects. Our results show that ApoA-I amyloidogenic variants are characterized by a different oligomerization pattern and that the position of the mutation in the ApoA-I sequence affects the molecular structure of the formed HDL particles. Although lipidation increases ApoA-I proteins stability, all the amyloidogenic variants analyzed show a lower affinity for lipids, both in vitro and in ex vivo mouse serum. Interestingly, the lower efficiency at forming HDL particles is compensated by a higher efficiency at catalysing cholesterol efflux from macrophages. The decreased affinity of ApoA-I amyloidogenic variants for lipids, together with the increased efficiency in the cholesterol efflux process, could explain why, despite the unfavourable lipid profile, patients affected by ApoA-I related amyloidosis do not show a higher CVD risk.
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Affiliation(s)
- Rita Del Giudice
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden.
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden
| | - Ilaria Iacobucci
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; CEINGE Biotecnologie Avanzate, 80145 Naples, Italy
| | - Oktawia Nilsson
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden
| | - Maria Monti
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy
| | - Daria Maria Monti
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden.
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17
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Del Giudice R, Domingo-Espin J, Monti DM, Lagerstedt JO. Inspecting the lipid binding capacity of APOA-I amyloidogenic variants. Atherosclerosis 2017. [DOI: 10.1016/j.atherosclerosis.2017.06.309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Domingo-Espín J, Lindahl M, Nilsson-Wolanin O, Cushman SW, Stenkula KG, Lagerstedt JO. Dual Actions of Apolipoprotein A-I on Glucose-Stimulated Insulin Secretion and Insulin-Independent Peripheral Tissue Glucose Uptake Lead to Increased Heart and Skeletal Muscle Glucose Disposal. Diabetes 2016; 65:1838-48. [PMID: 27207515 DOI: 10.2337/db15-1493] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/12/2016] [Indexed: 11/13/2022]
Abstract
Apolipoprotein A-I (apoA-I) of HDL is central to the transport of cholesterol in circulation. ApoA-I also provides glucose control with described in vitro effects of apoA-I on β-cell insulin secretion and muscle glucose uptake. In addition, apoA-I injections in insulin-resistant diet-induced obese (DIO) mice lead to increased glucose-stimulated insulin secretion (GSIS) and peripheral tissue glucose uptake. However, the relative contribution of apoA-I as an enhancer of GSIS in vivo and as a direct stimulator of insulin-independent glucose uptake is not known. Here, DIO mice with instant and transient blockade of insulin secretion were used in glucose tolerance tests and in positron emission tomography analyses. Data demonstrate that apoA-I to an equal extent enhances GSIS and acts as peripheral tissue activator of insulin-independent glucose uptake and verify skeletal muscle as an apoA-I target tissue. Intriguingly, our analyses also identify the heart as an important target tissue for the apoA-I-stimulated glucose uptake, with potential implications in diabetic cardiomyopathy. Explorations of apoA-I as a novel antidiabetic drug should extend to treatments of diabetic cardiomyopathy and other cardiovascular diseases in patients with diabetes.
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Affiliation(s)
- Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Maria Lindahl
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Samuel W Cushman
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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19
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Petrlova J, Hilt S, Budamagunta M, Domingo-Espín J, Voss JC, Lagerstedt JO. Molecular crowding impacts the structure of apolipoprotein A-I with potential implications on in vivo metabolism and function. Biopolymers 2016; 105:683-92. [PMID: 27122373 DOI: 10.1002/bip.22865] [Citation(s) in RCA: 3] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/14/2016] [Accepted: 04/25/2016] [Indexed: 11/08/2022]
Abstract
The effect molecular crowding, defined as the volume exclusion exerted by one soluble inert molecule upon another soluble molecule, has on the structure and self-interaction of lipid-free apoA-I were explored. The influence of molecular crowding on lipid-free apoA-I oligomerization and internal dynamics has been analyzed using electron paramagnetic resonance (EPR) spectroscopy measurements of nitroxide spin label at selected positions throughout the protein sequence and at varying concentrations of the crowding agent Ficoll-70. The targeted positions include sites previously shown to be sensitive for detecting intermolecular interaction via spin-spin coupling. Circular dichroism was used to study secondary structural changes in lipid-free apoA-I imposed by increasing concentrations of the crowding agent. Crosslinking and SDS-PAGE gel analysis was employed to further characterize the role molecular crowding plays in inducing apoA-I oligomerization. It was concluded that the dynamic apoA-I structure and oligomeric state was altered in the presence of the crowding agent. It was also found that the C-terminal was slightly more sensitive to molecular crowding. Finally, the data described the region around residue 217 in the C-terminal domain of apoA-I as the most sensitive reporter of the crowding-induced self-association of apoA-I. The implications of this behavior to in vivo functionality are discussed. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 683-692, 2016.
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Affiliation(s)
- Jitka Petrlova
- Department of Experimental Medical Science, Lund University, Lund, S-221 84, Sweden
| | - Silvia Hilt
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA, 95616
| | - Madhu Budamagunta
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA, 95616
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, Lund, S-221 84, Sweden
| | - John C Voss
- Department of Experimental Medical Science, Lund University, Lund, S-221 84, Sweden.,Department of Biochemistry and Molecular Medicine, University of California, Davis, CA, 95616
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, S-221 84, Sweden
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20
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Abstract
Apolipoprotein A-I (apoA-I) is the main protein involved in the formation of high-density lipoprotein (HDL), it is the principal mediator of the reverse cholesterol transfer (RCT) pathway and provides cardio-protection. In addition to functional wild-type apoA-I, several variants have been shown to associate with hereditary amyloidosis. In this study we have performed biophysical and biochemical analyses of the structure and functional properties of the A164S variant of apoA-I (1:500 in the Danish general population), which is the first known mutation of apoA-I that leads to an increased risk of ischaemic heart disease (IHD), myocardial infarction and mortality without associated low HDL cholesterol levels. Despite the fact that epidemiologically IHD is associated with low plasma levels of HDL, the A164S mutation is linked to normal plasma levels of lipids, HDL and apoA-I, suggesting impaired functionality of this variant. Using biophysical techniques (e.g., circular dichroism spectroscopy and electron microscopy) to determine secondary structure, stability and pro-amyloidogenic property of the lipid free A164S apoA-I variant, our observations suggest similarity in structural properties between apoA-I WT and apoA-I A164S. However, the A164S apoA-I variant exhibits lower binding affinity to lipids but forms similar sized HDL particles to those produced by WT.
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Affiliation(s)
| | - Jens O. Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail:
| | - Jitka Petrlova
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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21
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Lindahl M, Petrlova J, Dalla-Riva J, Wasserstrom S, Rippe C, Domingo-Espin J, Kotowska D, Krupinska E, Berggreen C, Jones HA, Swärd K, Lagerstedt JO, Göransson O, Stenkula KG. ApoA-I Milano stimulates lipolysis in adipose cells independently of cAMP/PKA activation. J Lipid Res 2015; 56:2248-59. [PMID: 26504176 DOI: 10.1194/jlr.m054767] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Indexed: 11/20/2022] Open
Abstract
ApoA-I, the main protein component of HDL, is suggested to be involved in metabolic homeostasis. We examined the effects of Milano, a naturally occurring ApoA-I variant, about which little mechanistic information is available. Remarkably, high-fat-fed mice treated with Milano displayed a rapid weight loss greater than ApoA-I WT treated mice, and a significantly reduced adipose tissue mass, without an inflammatory response. Further, lipolysis in adipose cells isolated from mice treated with either WT or Milano was increased. In primary rat adipose cells, Milano stimulated cholesterol efflux and increased glycerol release, independently of β-adrenergic stimulation and phosphorylation of hormone sensitive lipase (Ser563) and perilipin (Ser522). Stimulation with Milano had a significantly greater effect on glycerol release compared with WT but similar effect on cholesterol efflux. Pharmacological inhibition or siRNA silencing of ABCA1 did not diminish Milano-stimulated lipolysis, although binding to the cell surface was decreased, as analyzed by fluorescence microscopy. Interestingly, methyl-β-cyclodextrin, a well-described cholesterol acceptor, dose-dependently stimulated lipolysis. Together, these results suggest that decreased fat mass and increased lipolysis following Milano treatment in vivo is partly explained by a novel mechanism at the adipose cell level comprising stimulation of lipolysis independently of the canonical cAMP/protein kinase A signaling pathway.
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Affiliation(s)
- Maria Lindahl
- Medical Protein Science, Lund University, 221 84 Lund, Sweden Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
| | - Jitka Petrlova
- Medical Protein Science, Lund University, 221 84 Lund, Sweden
| | | | | | - Catarina Rippe
- Cellular Biomechanics, Lund University, 221 84 Lund, Sweden
| | | | - Dorota Kotowska
- Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
| | - Ewa Krupinska
- Medical Protein Science, Lund University, 221 84 Lund, Sweden
| | | | - Helena A Jones
- Molecular Endocrinology, Department of Experimental Medical Science, Biomedical Center, Lund University, 221 84 Lund, Sweden
| | - Karl Swärd
- Cellular Biomechanics, Lund University, 221 84 Lund, Sweden
| | | | - Olga Göransson
- Protein Phosphorylation, Lund University, 221 84 Lund, Sweden
| | - Karin G Stenkula
- Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
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22
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Skärstrand H, Krupinska E, Haataja TJK, Vaziri-Sani F, Lagerstedt JO, Lernmark Å. Zinc transporter 8 (ZnT8) autoantibody epitope specificity and affinity examined with recombinant ZnT8 variant proteins in specific ZnT8R and ZnT8W autoantibody-positive type 1 diabetes patients. Clin Exp Immunol 2015; 179:220-9. [PMID: 25178386 PMCID: PMC4298399 DOI: 10.1111/cei.12448] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2014] [Indexed: 02/06/2023] Open
Abstract
Variant-specific zinc transporter 8 autoantibodies (ZnT8A) against either arginine (R) or tryptophan (W) at amino acid (aa) position 325 of the zinc transporter 8 (ZnT8) has been identified in type 1 diabetes (T1D) patients. Reciprocal cross-over tests revealed differences in half-maximal binding to indicate variable affinity of patient ZnT8 autoantibodies. Insufficient recombinant ZnT8 variant proteins have precluded detailed analyses of ZnT8 autoantibody affinity. The aims in the present study were to (i) generate recombinant ZnT8R- and ZnT8W-aa275-369 proteins; (ii) test the ZnT8R- and ZnT8W-aa275-369 proteins in reciprocal competitive radiobinding assays (RBA) against ZnT8R- and ZnT8W-aa268-369 labelled with (35) S-methionine; and (iii) determine the specificity and affinity of sera specific for either ZnT8 arginine (R) or ZnT8 tryptophan (W) autoantibodies in newly diagnosed T1D patients. The results demonstrate, first, that it was possible to produce recombinant human MBP-ZnT8-aa275-369 protein purified to homogeneity for RBA reciprocal competition experiments. Secondly, high-titre ZnT8WA sera diluted to half maximal binding showed significant specificity for respective variants of either ZnT8R or ZnT8W. Thirdly, ZnT8WA-positive sera showed high affinity for ZnT8W compared to ZnT8RA for ZnT8R. These data demonstrate that T1D patients may have single amino acid-specific autoantibodies directed against either ZnT8R or ZnT8W and that the autoantibody affinity to the respective variant may be different. Further studies are needed to assess the mechanisms by which variant-specific ZnT8A of variable affinity develop and their possible role in the pathogenic process leading to the clinical onset of T1D.
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Affiliation(s)
- H Skärstrand
- Department of Clinical Sciences, Lund University, Skåne University Hospital, Malmö, Sweden
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23
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Petrlova J, Bhattacherjee A, Boomsma W, Wallin S, Lagerstedt JO, Irbäck A. Conformational and aggregation properties of the 1-93 fragment of apolipoprotein A-I. Protein Sci 2014; 23:1559-71. [PMID: 25131953 DOI: 10.1002/pro.2534] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 05/23/2014] [Revised: 07/11/2014] [Accepted: 08/04/2014] [Indexed: 11/12/2022]
Abstract
Several disease-linked mutations of apolipoprotein A-I, the major protein in high-density lipoprotein (HDL), are known to be amyloidogenic, and the fibrils often contain N-terminal fragments of the protein. Here, we present a combined computational and experimental study of the fibril-associated disordered 1-93 fragment of this protein, in wild-type and mutated (G26R, S36A, K40L, W50R) forms. In atomic-level Monte Carlo simulations of the free monomer, validated by circular dichroism spectroscopy, we observe changes in the position-dependent β-strand probability induced by mutations. We find that these conformational shifts match well with the effects of these mutations in thioflavin T fluorescence and transmission electron microscopy experiments. Together, our results point to molecular mechanisms that may have a key role in disease-linked aggregation of apolipoprotein A-I.
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Affiliation(s)
- Jitka Petrlova
- Department of Experimental Medical Science, Lund University, BMC Floor C12, SE-221 84, Lund, Sweden
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24
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Banke E, Rödström K, Ekelund M, Dalla-Riva J, Lagerstedt JO, Nilsson S, Degerman E, Lindkvist-Petersson K, Nilson B. Superantigen activates the gp130 receptor on adipocytes resulting in altered adipocyte metabolism. Metabolism 2014; 63:831-40. [PMID: 24684823 DOI: 10.1016/j.metabol.2014.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 09/18/2013] [Revised: 02/25/2014] [Accepted: 03/04/2014] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The bacteria Staphylococcus aureus is part of the normal bacterial flora and produces a repertoire of enterotoxins which can cause food poisoning and toxic shock and might contribute to the pathogenesis of inflammatory diseases. These enterotoxins directly cross-link the T cell receptor with MHC class II, activating large amounts of T cells and are therefore called superantigens. It was recently discovered that the superantigen SEA binds to the cytokine receptor gp130. As obesity and type 2 diabetes are highly associated with inflammation of the adipose tissue and gp130 has been shown to play an important role in adipocytes, we wanted to investigate the effect of SEA on adipocyte signaling and function. MATERIALS/METHODS Binding of SEA to gp130 was examined using surface plasmon resonance in a cell free system. Effects of SEA on adipocyte signaling, insulin sensitivity and function were studied using western blotting and biological assays for lipolysis, lipogenesis and glucose uptake. RESULTS We demonstrate that SEA binds to gp130 with a medium affinity. Furthermore, SEA induces phosphorylation of a key downstream target, STAT3, in adipocytes. SEA also inhibits insulin-induced activation of PKB and PKB downstream signaling which was associated with reduced basal and insulin induced glucose uptake, reduced lipogenesis as well as reduced ability of insulin to inhibit lipolysis. CONCLUSIONS SEA inhibits insulin signaling as well as insulin biological responses in adipocytes supporting that bacterial infection might contribute to the development of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Elin Banke
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden.
| | - Karin Rödström
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | - Mikael Ekelund
- Department of Surgery, Skåne University Hospital & Lund University, 221 85 Lund, Sweden
| | - Jonathan Dalla-Riva
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | - Staffan Nilsson
- Pure and Applied Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, 221 00 Lund, Sweden
| | - Eva Degerman
- Department of Experimental Medical Science, Lund University, BMC, 221 84 Lund, Sweden
| | | | - Bo Nilson
- Department of Laboratory Medicine, Division of Medicinal Microbiology, Lund University, 223 62 Lund, Sweden; Department of Clinical Microbiology, University and Regional Laboratories in Region Skåne, 221 85 Lund, Sweden
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25
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Petrlova J, Dalla-Riva J, Mörgelin M, Lindahl M, Krupinska E, Stenkula KG, Voss JC, Lagerstedt JO. Secondary structure changes in ApoA-I Milano (R173C) are not accompanied by a decrease in protein stability or solubility. PLoS One 2014; 9:e96150. [PMID: 24755625 PMCID: PMC3995965 DOI: 10.1371/journal.pone.0096150] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 04/04/2014] [Indexed: 11/29/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) is the main protein of high-density lipoprotein (HDL) and a principal mediator of the reverse cholesterol transfer pathway. Variants of apoA-I have been shown to be associated with hereditary amyloidosis. We previously characterized the G26R and L178H variants that both possess decreased stability and increased fibril formation propensity. Here we investigate the Milano variant of apoAI (R173C; apoAI-M), which despite association with low plasma levels of HDL leads to low prevalence of cardiovascular disease in carriers of this mutation. The R173C substitution is located to a region (residues 170 to 178) that contains several fibrillogenic apoA-I variants, including the L178H variant, and therefore we investigated a potential fibrillogenic property of the apoAI-M protein. Despite the fact that apoAI-M shared several features with the L178H variant regarding increased helical content and low degree of ThT binding during prolonged incubation in physiological buffer, our electron microscopy analysis revealed no formation of fibrils. These results suggest that mutations inducing secondary structural changes may be beneficial in cases where fibril formation does not occur.
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Affiliation(s)
- Jitka Petrlova
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | | | - Maria Lindahl
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Ewa Krupinska
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Karin G. Stenkula
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - John C. Voss
- School of Medicine, University of California Davis, Davis, California, United States of America
| | - Jens O. Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail:
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26
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Stenkula KG, Lindahl M, Petrlova J, Dalla-Riva J, Göransson O, Cushman SW, Krupinska E, Jones HA, Lagerstedt JO. Single injections of apoA-I acutely improve in vivo glucose tolerance in insulin-resistant mice. Diabetologia 2014; 57:797-800. [PMID: 24442447 PMCID: PMC3940850 DOI: 10.1007/s00125-014-3162-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [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: 11/01/2013] [Accepted: 12/19/2013] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS Apolipoprotein A-I (apoA-I), the main protein constituent of HDL, has a central role in the reverse cholesterol-transport pathway, which together with the anti-inflammatory properties of apoA-I/HDL provide cardioprotection. Recent findings of direct stimulation of glucose uptake in muscle by apoA-I/HDL suggest that altered apoA-I and HDL functionality may be a contributing factor to the development of diabetes. We have studied the in vivo effects of short treatments with human apoA-I in a high-fat diet fed mouse model. In addition to native apoA-I, we investigated the effects of the cardioprotective Milano variant (Arg173Cys). METHODS Male C57Bl6 mice on a high-fat diet for 2 weeks that received a single injection of human apoA-I proteins (wild-type and Milano) were analysed for blood glucose and insulin levels during a 3 h incubation followed by glucose tolerance tests. Incorporation of injected human apoA-I protein into HDLs was analysed by native gel electrophoresis. RESULTS ApoA-I treatment significantly improved insulin secretion and blood glucose clearance in the glucose tolerance test, with an efficiency exceeding that of lean control animals, and led to decreased basal glucose during the 3 h incubation. Notably, the two apoA-I variants triggered insulin secretion and glucose clearance to the same extent. CONCLUSIONS/INTERPRETATION ApoA-I treatment leads to insulin- and non-insulin-dependent effects on glucose homeostasis. The experimental model of short-term (2 weeks) feeding of a high-fat diet to C57Bl6 mice provides a suitable and time-efficient system to unravel the resulting tissue-specific mechanisms of acute apoA-I treatment that lead to improved glucose homeostasis.
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Affiliation(s)
- Karin G. Stenkula
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Maria Lindahl
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Jitka Petrlova
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Jonathan Dalla-Riva
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Olga Göransson
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Samuel W. Cushman
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Ewa Krupinska
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Helena A. Jones
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
| | - Jens O. Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
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27
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Lagerstedt JO, Petrlova J, Hilt S, Marek A, Chung Y, Sriram R, Budamagunta MS, Desreux JF, Thonon D, Jue T, Smirnov AI, Voss JC. EPR assessment of protein sites for incorporation of Gd(III) MRI contrast labels. Contrast Media Mol Imaging 2013; 8:252-64. [PMID: 23606429 DOI: 10.1002/cmmi.1518] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 10/30/2012] [Accepted: 11/03/2012] [Indexed: 11/06/2022]
Abstract
We have engineered apolipoprotein A-I (apoA-I), a major protein constituent of high-density lipoprotein (HDL), to contain DOTA-chelated Gd(III) as an MRI contrast agent for the purpose of imaging reconstituted HDL (rHDL) biodistribution, metabolism and regulation in vivo. This protein contrast agent was obtained by attaching the thiol-reactive Gd[MTS-ADO3A] label at Cys residues replaced at four distinct positions (52, 55, 76 and 80) in apoA-I. MRI of infused mice previously showed that the Gd-labeled apoA-I migrates to both the liver and the kidney, the organs responsible for HDL catabolism; however, the contrast properties of apoA-I are superior when the ADO3A moiety is located at position 55, compared with the protein labeled at positions 52, 76 or 80. It is shown here that continuous wave X-band (9 GHz) electron paramagnetic resonance (EPR) spectroscopy is capable of detecting differences in the Gd(III) signal when comparing the labeled protein in the lipid-free with the rHDL state. Furthermore, the values of NMR relaxivity obtained for labeled variants in both the lipid-free and rHDL states correlate to the product of the X-band Gd(III) spectral width and the collision frequency between a nitroxide spin label and a polar relaxation agent. Consistent with its superior relaxivity measured by NMR, the rHDL-associated apoA-I containing the Gd[MTS-ADO3A] probe attached to position 55 displays favorable dynamic and water accessibility properties as determined by X-band EPR. While room temperature EPR requires >1 m m Gd(III)-labeled and only >10 µ m nitroxide-labeled protein to resolve the spectrum, the volume requirement is exceptionally low (~5 µl). Thus, X-band EPR provides a practical assessment for the suitability of imaging candidates containing the site-directed ADO3A contrast probe.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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28
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Myers WK, Xu X, Li C, Lagerstedt JO, Budamagunta MS, Voss JC, Britt RD, Ames JB. Double electron-electron resonance probes Ca²⁺-induced conformational changes and dimerization of recoverin. Biochemistry 2013; 52:5800-8. [PMID: 23906368 DOI: 10.1021/bi400538w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recoverin, a member of the neuronal calcium sensor (NCS) branch of the calmodulin superfamily, is expressed in retinal photoreceptor cells and serves as a calcium sensor in vision. Ca²⁺-induced conformational changes in recoverin cause extrusion of its covalently attached myristate (termed Ca²⁺-myristoyl switch) that promotes translocation of recoverin to disk membranes during phototransduction in retinal rod cells. Here we report double electron-electron resonance (DEER) experiments on recoverin that probe Ca²⁺-induced changes in distance as measured by the dipolar coupling between spin-labels strategically positioned at engineered cysteine residues on the protein surface. The DEER distance between nitroxide spin-labels attached at C39 and N120C is 2.5 ± 0.1 nm for Ca²⁺-free recoverin and 3.7 ± 0.1 nm for Ca²⁺-bound recoverin. An additional DEER distance (5-6 nm) observed for Ca²⁺-bound recoverin may represent an intermolecular distance between C39 and N120. ¹⁵N NMR relaxation analysis and CW-EPR experiments both confirm that Ca²⁺-bound recoverin forms a dimer at protein concentrations above 100 μM, whereas Ca²⁺-free recoverin is monomeric. We propose that Ca²⁺-induced dimerization of recoverin at the disk membrane surface may play a role in regulating Ca²⁺-dependent phosphorylation of dimeric rhodopsin. The DEER approach will be useful for elucidating dimeric structures of NCS proteins in general for which Ca²⁺-induced dimerization is functionally important but not well understood.
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Affiliation(s)
- William K Myers
- Department of Chemistry, University of California, Davis, California 95616, United States
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29
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Oda MN, Budamagunta MS, Borja MS, Petrlova J, Voss JC, Lagerstedt JO. The secondary structure of apolipoprotein A-I on 9.6-nm reconstituted high-density lipoprotein determined by EPR spectroscopy. FEBS J 2013; 280:3416-24. [PMID: 23668303 PMCID: PMC3906832 DOI: 10.1111/febs.12334] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [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: 02/20/2013] [Revised: 05/09/2013] [Accepted: 05/09/2013] [Indexed: 01/09/2023]
Abstract
Apolipoprotein A-I (ApoA-I) is the major protein component of high-density lipoprotein (HDL), and is critical for maintenance of cholesterol homeostasis. During reverse cholesterol transport, HDL transitions between an array of subclasses, differing in size and composition. This process requires ApoA-I to adapt to changes in the shape of the HDL particle, transiting from an apolipoprotein to a myriad of HDL subclass-specific conformations. Changes in ApoA-I structure cause alterations in HDL-specific enzyme and receptor-binding properties, and thereby direct the HDL particle through the reverse cholesterol transport pathway. In this study, we used site-directed spin label spectroscopy to examine the conformational details of the ApoA-I central domain on HDL. The motional dynamics and accessibility to hydrophobic/hydrophilic relaxation agents of ApoA-I residues 99–163 on 9.6-nm reconstituted HDL was analyzed by EPR. In previous analyses, we examined residues 6–98 and 164–238 (of ApoA-I's 243 residues), and combining these findings with the current results, we have generated a full-length map of the backbone structure of reconstituted HDL-associated ApoA-I. Remarkably, given that the majority of ApoA-I's length is composed of amphipathic helices, we have identified nonhelical residues, specifically the presence of a β-strand (residues 149–157). The significance of these nonhelical residues is discussed, along with the other features, in the context of ApoA-I function in contrast to recent models derived by other methods.
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Affiliation(s)
- Michael N Oda
- Children's Hospital Oakland Research Institute, CA, USA
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30
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Abstract
Lipid-free apoA-I and mature spherical HDL have been shown to induce glucose uptake in skeletal muscle. To exploit apoA-I and HDL states for diabetes therapy, further understanding of interaction between muscle and apoA-I is required. This study has examined whether nascent discoidal HDL, in which apoA-I attains a different conformation from mature HDL and lipid-free states, could induce muscle glucose uptake and whether a specific domain of apoA-I can mediate this effect. Using L6 myotubes stimulated with synthetic reconstituted discoidal HDL (rHDL), we show a glucose uptake effect comparable to insulin. Increased plasma membrane GLUT4 levels in ex vivo rHDL-stimulated myofibers from HA-GLUT4-GFP transgenic mice support this observation. rHDL increased phosphorylation of AMP kinase (AMPK) and acetyl-coA carboxylase (ACC) but not Akt. A survey of domain-specific peptides of apoA-I showed that the lipid-free C-terminal 190-243 fragment increases plasma membrane GLUT4, promotes glucose uptake, and activates AMPK signaling but not Akt. This may be explained by changes in α-helical content of 190-243 fragment versus full-length lipid-free apoA-I as assessed by circular dichroism spectroscopy. Discoidal HDL and the 190-243 peptide of apoA-I are potent agonists of glucose uptake in skeletal muscle, and the C-terminal α-helical content of apoA-I may be an important determinant of this effect.
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Affiliation(s)
- Jonathan Dalla-Riva
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
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31
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Sengottaiyan P, Spetea C, Lagerstedt JO, Samyn D, Andersson M, Ruiz-Pavón L, Persson BL. The intrinsic GTPase activity of the Gtr1 protein from Saccharomyces cerevisiae. BMC Biochem 2012; 13:11. [PMID: 22726655 PMCID: PMC3477016 DOI: 10.1186/1471-2091-13-11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 06/24/2012] [Indexed: 12/26/2022]
Abstract
Background The Gtr1 protein of Saccharomyces cerevisiae is a member of the RagA subfamily of the Ras-like small GTPase superfamily. Gtr1 has been implicated in various cellular processes. Particularly, the Switch regions in the GTPase domain of Gtr1 are essential for TORC1 activation and amino acid signaling. Therefore, knowledge about the biochemical activity of Gtr1 is required to understand its mode of action and regulation. Results By employing tryptophan fluorescence analysis and radioactive GTPase assays, we demonstrate that Gtr1 can adopt two distinct GDP- and GTP-bound conformations, and that it hydrolyses GTP much slower than Ras proteins. Using cysteine mutagenesis of Arginine-37 and Valine-67, residues at the Switch I and II regions, respectively, we show altered GTPase activity and associated conformational changes as compared to the wild type protein and the cysteine-less mutant. Conclusions The extremely low intrinsic GTPase activity of Gtr1 implies requirement for interaction with activating proteins to support its physiological function. These findings as well as the altered properties obtained by mutagenesis in the Switch regions provide insights into the function of Gtr1 and its homologues in yeast and mammals.
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32
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Petrlova J, Zhu L, Mörgelin M, Hebert H, Jegerschöld C, Voss JC, Lagerstedt JO. Structural properties of functional HDL and variants of apoA‐I. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.997.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Lin Zhu
- School of Technology and HealthRoyal Institute of TechnologyHuddingeSweden
| | | | - Hans Hebert
- School of Technology and HealthRoyal Institute of TechnologyHuddingeSweden
- Department of Biosciences and Medical NutritionKarolinska InstituteHuddingeSweden
| | - Caroline Jegerschöld
- Department of Biosciences and Medical NutritionKarolinska InstituteHuddingeSweden
| | - John C. Voss
- Departments of Experimental Medical ScienceLund UniversityLundSweden
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33
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Lagerstedt JO, Budamagunta MS, Liu GS, DeValle NC, Voss JC, Oda MN. The "beta-clasp" model of apolipoprotein A-I--a lipid-free solution structure determined by electron paramagnetic resonance spectroscopy. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:448-55. [PMID: 22245143 DOI: 10.1016/j.bbalip.2011.12.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Revised: 12/06/2011] [Accepted: 12/20/2011] [Indexed: 02/02/2023]
Abstract
Apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins (HDL) and plays a central role in cholesterol metabolism. The lipid-free/lipid-poor form of apoA-I is the preferred substrate for the ATP-binding cassette transporter A1 (ABCA1). The interaction of apoA-I with ABCA1 leads to the formation of cholesterol laden high density lipoprotein (HDL) particles, a key step in reverse cholesterol transport and the maintenance of cholesterol homeostasis. Knowledge of the structure of lipid-free apoA-I is essential to understanding its critical interaction with ABCA1 and the molecular mechanisms underlying HDL biogenesis. We therefore examined the structure of lipid-free apoA-I by electron paramagnetic resonance spectroscopy (EPR). Through site directed spin label EPR, we mapped the secondary structure of apoA-I and identified sites of spin coupling as residues 26, 44, 64, 167, 217 and 226. We capitalize on the fact that lipid-free apoA-I self-associates in an anti-parallel manner in solution. We employed these sites of spin coupling to define the central plane in the dimeric apoA-I complex. Applying both the constraints of dipolar coupling with the EPR-derived pattern of solvent accessibility, we assembled the secondary structure into a tertiary context, providing a solution structure for lipid-free apoA-I. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).
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Affiliation(s)
- Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
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34
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Petrlova J, Duong T, Cochran MC, Axelsson A, Mörgelin M, Roberts LM, Lagerstedt JO. The fibrillogenic L178H variant of apolipoprotein A-I forms helical fibrils. J Lipid Res 2011; 53:390-398. [PMID: 22184756 PMCID: PMC3276462 DOI: 10.1194/jlr.m020883] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [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] [Indexed: 01/24/2023] Open
Abstract
A number of amyloidogenic variants of apoA-I have been discovered but most have not
been analyzed. Previously, we showed that the G26R mutation of apoA-I leads to
increased β-strand structure, increased N-terminal protease susceptibility, and
increased fibril formation after several days of incubation. In vivo, this and other
variants mutated in the N-terminal domain (residues 26 to ∼90) lead to renal and
hepatic accumulation. In contrast, several mutations identified within residues 170
to 178 lead to cardiac, laryngeal, and cutaneous protein deposition. Here, we
describe the structural changes in the fibrillogenic variant L178H. Like G26R, the
initial structure of the protein exhibits altered tertiary conformation relative to
wild-type protein along with decreased stability and an altered lipid binding
profile. However, in contrast to G26R, L178H undergoes an increase in helical
structure upon incubation at 37°C with a half time (t1/2) of about 12
days. Upon prolonged incubation, the L178H mutant forms fibrils of a diameter of 10
nm that ranges in length from 30 to 120 nm. These results show that apoA-I, known for
its dynamic properties, has the ability to form multiple fibrillar conformations,
which may play a role in the tissue-specific deposition of the individual
variants.
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Affiliation(s)
- Jitka Petrlova
- Department of Experimental Medical Sciences, Lund University, S-221 84 Lund, Sweden; and
| | - Trang Duong
- Department of Chemistry, California State University Sacramento, Sacramento, CA 95819
| | - Megan C Cochran
- Department of Chemistry, California State University Sacramento, Sacramento, CA 95819
| | - Annika Axelsson
- Department of Experimental Medical Sciences, Lund University, S-221 84 Lund, Sweden; and
| | - Matthias Mörgelin
- Department of Experimental Medical Sciences, and Department of Infection Medicine, Lund University, S-221 84 Lund, Sweden; and
| | - Linda M Roberts
- Department of Chemistry, California State University Sacramento, Sacramento, CA 95819.
| | - Jens O Lagerstedt
- Department of Experimental Medical Sciences, Lund University, S-221 84 Lund, Sweden; and.
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35
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Sriram R, Lagerstedt JO, Petrlova J, Samardzic H, Kreutzer U, Xie H, Kaysen GA, Desreux JF, Thonon D, Jacques V, Van Loan M, Rutledge JC, Oda MN, Voss JC, Jue T. Imaging apolipoprotein AI in vivo. NMR Biomed 2011; 24:916-24. [PMID: 21264979 PMCID: PMC3726305 DOI: 10.1002/nbm.1650] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [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] [Received: 12/01/2009] [Revised: 10/20/2010] [Accepted: 10/31/2010] [Indexed: 05/30/2023]
Abstract
Coronary disease risk increases inversely with high-density lipoprotein (HDL) level. The measurement of the biodistribution and clearance of HDL in vivo, however, has posed a technical challenge. This study presents an approach to the development of a lipoprotein MRI agent by linking gadolinium methanethiosulfonate (Gd[MTS-ADO3A]) to a selective cysteine mutation in position 55 of apo AI, the major protein of HDL. The contrast agent targets both liver and kidney, the sites of HDL catabolism, whereas the standard MRI contrast agent, gadolinium-diethylenetriaminepentaacetic acid-bismethylamide (GdDTPA-BMA, gadodiamide), enhances only the kidney image. Using a modified apolipoprotein AI to create an HDL contrast agent provides a new approach to investigate HDL biodistribution, metabolism and regulation in vivo.
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Affiliation(s)
- Renuka Sriram
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | | | - Jitka Petrlova
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - Haris Samardzic
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - Ulrike Kreutzer
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - Hongtao Xie
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - George A. Kaysen
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - Jean F. Desreux
- Coordination and Radiochemistry, University of Liege, Liege, Belgium
| | - David Thonon
- Coordination and Radiochemistry, University of Liege, Liege, Belgium
| | | | - Martha Van Loan
- Nutrition Department, University of California Davis, Davis, CA, USA
| | - John C. Rutledge
- Division of Endocrinology, Clinical Nutrition and Vascular Medicine, Department of Internal Medicine, University of California Davis, Davis, CA, USA
| | - Michael N. Oda
- Children’s Hospital Oakland Research Institute, Oakland, CA, USA
| | - John C. Voss
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
| | - Thomas Jue
- Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, USA
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36
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Lagerstedt JO, Cavigiolio G, Budamagunta MS, Pagani I, Voss JC, Oda MN. Structure of apolipoprotein A-I N terminus on nascent high density lipoproteins. J Biol Chem 2010; 286:2966-75. [PMID: 21047795 DOI: 10.1074/jbc.m110.163097] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) is the major protein component of high density lipoproteins (HDL) and a critical element of cholesterol metabolism. To better elucidate the role of the apoA-I structure-function in cholesterol metabolism, the conformation of the apoA-I N terminus (residues 6-98) on nascent HDL was examined by electron paramagnetic resonance (EPR) spectroscopic analysis. A series of 93 apoA-I variants bearing single nitroxide spin label at positions 6-98 was reconstituted onto 9.6-nm HDL particles (rHDL). These particles were subjected to EPR spectral analysis, measuring regional flexibility and side chain solvent accessibility. Secondary structure was elucidated from side-chain mobility and molecular accessibility, wherein two major α-helical domains were localized to residues 6-34 and 50-98. We identified an unstructured segment (residues 35-39) and a β-strand (residues 40-49) between the two helices. Residues 14, 19, 34, 37, 41, and 58 were examined by EPR on 7.8, 8.4, and 9.6 nm rHDL to assess the effect of particle size on the N-terminal structure. Residues 14, 19, and 58 showed no significant rHDL size-dependent spectral or accessibility differences, whereas residues 34, 37, and 41 displayed moderate spectral changes along with substantial rHDL size-dependent differences in molecular accessibility. We have elucidated the secondary structure of the N-terminal domain of apoA-I on 9.6 nm rHDL (residues 6-98) and identified residues in this region that are affected by particle size. We conclude that the inter-helical segment (residues 35-49) plays a role in the adaptation of apoA-I to the particle size of HDL.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84 Lund, Sweden
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37
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Nygaard EB, Lagerstedt JO, Bjerre G, Shi B, Budamagunta M, Poulsen KA, Meinild S, Rigor RR, Voss JC, Cala PM, Pedersen SF. Structural modeling and electron paramagnetic resonance spectroscopy of the human Na+/H+ exchanger isoform 1, NHE1. J Biol Chem 2010; 286:634-48. [PMID: 20974853 DOI: 10.1074/jbc.m110.159202] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously presented evidence that transmembrane domain (TM) IV and TM X-XI are important for inhibitor binding and ion transport by the human Na(+)/H(+) exchanger, hNHE1 (Pedersen, S. F., King, S. A., Nygaard, E. B., Rigor, R. R., and Cala, P. M. (2007) J. Biol. Chem. 282, 19716-19727). Here, we present a structural model of the transmembrane part of hNHE1 that further supports this conclusion. The hNHE1 model was based on the crystal structure of the Escherichia coli Na(+)/H(+) antiporter, NhaA, and previous cysteine scanning accessibility studies of hNHE1 and was validated by EPR spectroscopy of spin labels in TM IV and TM XI, as well as by functional analysis of hNHE1 mutants. Removal of all endogenous cysteines in hNHE1, introduction of the mutations A173C (TM IV) and/or I461C (TM XI), and expression of the constructs in mammalian cells resulted in functional hNHE1 proteins. The distance between these spin labels was ∼15 A, confirming that TM IV and TM XI are in close proximity. This distance was decreased both at pH 5.1 and in the presence of the NHE1 inhibitor cariporide. A similar TM IV·TM XI distance and a similar change upon a pH shift were found for the cariporide-insensitive Pleuronectes americanus (pa) NHE1; however, in paNHE1, cariporide had no effect on TM IV·TM XI distance. The central role of the TM IV·TM XI arrangement was confirmed by the partial loss of function upon mutation of Arg(425), which the model predicts stabilizes this arrangement. The data are consistent with a role for TM IV and TM XI rearrangements coincident with ion translocation and inhibitor binding by hNHE1.
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Affiliation(s)
- Eva B Nygaard
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
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38
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Lundh F, Mouillon JM, Samyn D, Stadler K, Popova Y, Lagerstedt JO, Thevelein JM, Persson BL. Molecular Mechanisms Controlling Phosphate-Induced Downregulation of the Yeast Pho84 Phosphate Transporter. Biochemistry 2009; 48:4497-505. [DOI: 10.1021/bi9001198] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Vinchurkar MS, Bricarello DA, Lagerstedt JO, Buban JP, Stahlberg H, Oda MN, Voss JC, Parikh AN. Bridging Across Length Scales: Multi-Scale Ordering of Supported Lipid Bilayers via Lipoprotein Self-assembly and Surface Patterning. J Am Chem Soc 2008; 130:11164-9. [DOI: 10.1021/ja803110v] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Madhuri S. Vinchurkar
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - Daniel A. Bricarello
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - Jens O. Lagerstedt
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - James P. Buban
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - Henning Stahlberg
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - Michael N. Oda
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - John C. Voss
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
| | - Atul N. Parikh
- Departments of Applied Science, Biochemistry & Molecular Medicine, Molecular and Cellular Biology, University of California, Davis, California 95616, and Lipid Biology in Health and Disease Research Group, Oakland Research Institute, Oakland, California 94609
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40
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Lagerstedt JO, Cavigiolio G, Roberts LM, Hong HS, Jin LW, Fitzgerald P, Oda MN, Voss JC. Mapping the structural transition in an amyloidogenic apolipoprotein A-I. Biochemistry 2007; 46:9693-9. [PMID: 17665932 PMCID: PMC3650831 DOI: 10.1021/bi7005493] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The single amino acid mutation G26R in human apolipoprotein A-I (apoA-IIOWA) leads to the formation of beta-secondary structure rich amyloid fibrils in vivo. Here we show that full-length apoA-IIOWA has a decreased lipid-binding capability, an increased amino-terminal sensitivity to protease, and a propensity to form annular protofibrils visible by electron microscopy. The molecular basis for the conversion of apolipoprotein A-I to a proamyloidogenic form was examined by electron paramagnetic resonance spectroscopy. Our recent findings [Lagerstedt, J. O., Budamagunta, M. S., Oda, M. N., and Voss, J. C. (2007) J. Biol. Chem. 282, 9143-9149] indicate that Gly26 in the native apoprotein separates a preceding beta-strand structure (residues 20-25) from a downstream largely alpha-helical region. The current study demonstrates that the G26R variant promotes a structural transition of positions 27-56 to a mixture of coil and beta-strand secondary structure. Microscopy and staining by amyloidophilic dyes suggest that this alteration extends throughout the protein within 1 week of incubation in vitro, leading to insoluble aggregates of distinct morphology. The severe consequences of the Iowa mutation likely arise from the combination of losing the contribution of the native Gly residue in terminating beta-strand propagation and the promotion of beta-structure when an Arg is introduced adjacent to the succeeding residue of identical charge and size, Arg27.
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Affiliation(s)
- Jens O. Lagerstedt
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616
- Department of Internal Medicine, University of California, Davis, CA 95616
| | - Giorgio Cavigiolio
- Department of Cell Biology and Human Anatomy, University of California, Davis, CA 95616
| | - Linda M. Roberts
- Department of Chemistry California State University, Sacramento, CA 95819
| | - Hyun-Seok Hong
- Department of Pathology, University of California, Davis, CA 95616
| | - Lee-Way Jin
- Department of Pathology, University of California, Davis, CA 95616
| | - Paul Fitzgerald
- Department of Cell Biology and Human Anatomy, University of California, Davis, CA 95616
| | - Michael N. Oda
- Children’s Hospital Oakland Research Institute, Oakland, CA 94609
| | - John C. Voss
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616
- Corresponding author: Tel: +1 530 754 7583; Fax: +1 530 752 3516;
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41
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Thuswaldner S, Lagerstedt JO, Rojas-Stütz M, Bouhidel K, Der C, Leborgne-Castel N, Mishra A, Marty F, Schoefs B, Adamska I, Persson BL, Spetea C. Identification, expression, and functional analyses of a thylakoid ATP/ADP carrier from Arabidopsis. J Biol Chem 2007; 282:8848-59. [PMID: 17261580 DOI: 10.1074/jbc.m609130200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In plants the chloroplast thylakoid membrane is the site of light-dependent photosynthetic reactions coupled to ATP synthesis. The ability of the plant cell to build and alter this membrane system is essential for efficient photosynthesis. A nucleotide translocator homologous to the bovine mitochondrial ADP/ATP carrier (AAC) was previously found in spinach thylakoids. Here we have identified and characterized a thylakoid ATP/ADP carrier (TAAC) from Arabidopsis.(i) Sequence homology with the bovine AAC and the prediction of chloroplast transit peptides indicated a putative carrier encoded by the At5g01500 gene, as a TAAC. (ii) Transiently expressed TAAC-green fluorescent protein fusion construct was targeted to the chloroplast. Western blotting using a peptide-specific antibody together with immunogold electron microscopy revealed a major location of TAAC in the thylakoid membrane. Previous proteomic analyses identified this protein in chloroplast envelope preparations. (iii) Recombinant TAAC protein specifically imports ATP in exchange for ADP across the cytoplasmic membrane of Escherichia coli. Studies on isolated thylakoids from Arabidopsis confirmed these observations. (iv) The lack of TAAC in an Arabidopsis T-DNA insertion mutant caused a 30-40% reduction in the thylakoid ATP transport and metabolism. (v) TAAC is readily expressed in dark-grown Arabidopsis seedlings, and its level remains stable throughout the greening process. Its expression is highest in developing green tissues and in leaves undergoing senescence or abiotic stress. We propose that the TAAC protein supplies ATP for energy-dependent reactions during thylakoid biogenesis and turnover in plants.
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Affiliation(s)
- Sophie Thuswaldner
- Division of Cell Biology, Linköping University, SE-581 85 Linköping, Sweden
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42
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Lagerstedt JO, Budamagunta MS, Oda MN, Voss JC. Electron paramagnetic resonance spectroscopy of site-directed spin labels reveals the structural heterogeneity in the N-terminal domain of apoA-I in solution. J Biol Chem 2007; 282:9143-9. [PMID: 17204472 DOI: 10.1074/jbc.m608717200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) is the major protein constituent of high density lipoprotein (HDL) and plays a central role in phospholipid and cholesterol metabolism. This 243-residue long protein is remarkably flexible and assumes numerous lipid-dependent conformations. Consequently, definitive structural determination of lipid-free apoA-I in solution has been difficult. Using electron paramagnetic spectroscopy of site-directed spin labels in the N-terminal domain of apoA-I (residues 1-98) we have mapped a mixture of secondary structural elements, the composition of which is consistent with findings from other in-solution methods. Based on side chain mobility and their accessibility to polar and non-polar spin relaxers, the precise location of secondary elements for amino acids 14-98 was determined for both lipid-free and lipid-bound apoA-I. Based on intermolecular dipolar coupling at positions 26, 44, and 64, these secondary structural elements were arranged into a tertiary fold to generate a structural model for lipid-free apoA-I in solution.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Biochemistry, University of California, Davis, California 95616, USA
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43
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Lagerstedt JO, Reeve I, Voss JC, Persson BL. Structure and function of the GTP binding protein Gtr1 and its role in phosphate transport in Saccharomyces cerevisiae. Biochemistry 2005; 44:511-7. [PMID: 15641775 DOI: 10.1021/bi048659v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Pho84 high-affinity phosphate permease is the primary phosphate transporter in the yeast Saccharomyces cerevisiae under phosphate-limiting conditions. The soluble G protein, Gtr1, has previously been suggested to be involved in the derepressible Pho84 phosphate uptake function. This idea was based on a displayed deletion phenotype of Deltagtr1 similar to the Deltapho84 phenotype. As of yet, the mode of interaction has not been described. The consequences of a deletion of gtr1 on in vivo Pho84 expression, trafficking and activity, and extracellular phosphatase activity were analyzed in strains synthesizing either Pho84-green fluorescent protein or Pho84-myc chimeras. The studies revealed a delayed response in Pho84-mediated phosphate uptake and extracellular phosphatase activity under phosphate-limiting conditions. EPR spectroscopic studies verified that the N-terminal G binding domain (residues 1-185) harbors the nucleotide responsive elements. In contrast, the spectra obtained for the C-terminal part (residues 186-310) displayed no evidence of conformational changes upon GTP addition.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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Lagerstedt JO, Voss JC, Wieslander A, Persson BL. Structural modeling of dual-affinity purified Pho84 phosphate transporter. FEBS Lett 2005; 578:262-8. [PMID: 15589830 DOI: 10.1016/j.febslet.2004.11.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Revised: 10/20/2004] [Accepted: 11/04/2004] [Indexed: 11/16/2022]
Abstract
The phosphate transporter Pho84 of Saccharomyces cerevisiae is predicted to contain 12 transmembrane (TM) regions, divided into two partially duplicated parts of 6 TM segments. The three-dimensional (3D) organization of the Pho84 protein has not yet been determined. However, the 3D crystal structure of the Escherichia coli MFS glycerol-3-phosphate/phosphate antiporter, GlpT, and lactose transporter, LacY, has recently been determined. On the basis of extensive prediction and fold recognition analyses (at the MetaServer), GlpT was proposed as the best structural template on which the arrangement of TM segments of the Pho84 transporter was fit, using the comparative structural modeling program MODELLER. To initiate an evaluation of the appropriateness of the Pho84 model, we have performed two direct tests by targeting spin labels to putative TM segments 8 and 12. Electron paramagnetic resonance spectroscopy was then applied on purified and spin labeled Pho84. The line shape from labels located at both positions is consistent with the structural environment predicted by the template-generated model, thus supporting the model.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Chemistry and Biomedical Sciences, Kalmar University, S-391 82 Kalmar, Sweden
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Pratt JR, Mouillon JM, Lagerstedt JO, Pattison-Granberg J, Lundh KI, Persson BL. Effects of methylphosphonate, a phosphate analogue, on the expression and degradation of the high-affinity phosphate transporter Pho84, in Saccharomyces cerevisiae. Biochemistry 2005; 43:14444-53. [PMID: 15533049 DOI: 10.1021/bi049327t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In Saccharomyces cerevisiae, the Pho84 high-affinity transport system is the major phosphate transporter activated when the cells experience a limitation in external phosphate. In this study, we have compared the phosphate-responsive mechanism of cells expressing PHO84 with a Deltapho84 strain by use of a phosphate analogue, methylphosphonate, which was judged to be suitable for assessment of phosphate homeostasis in the cells. Intracellular levels of the analogue, which in several respects mimicks phosphate, were monitored by (31)P NMR spectroscopy. Results show that methylphosphonate is a nonhydrolyzable and nonutilizable analogue that cannot be used to replenish phosphate or polyphosphate in yeast cells grown under conditions of phosphate limitation. However, the presence of methylphosphonate under such conditions represses the Pho5 acidic phosphatase activity of PHO84 cells, a finding that implies a direct role of the analogue in the regulation of phosphate-responsive genes and/or proteins. Likewise, accumulation of the Pho84 protein at the plasma membrane of the same cells is inhibited by methylphosphonate, although the derepressive expression of the PHO84 gene is unperturbed. Thus, a post-transcriptional regulation is suggested. Supportive of this suggestion is the fact that addition of methylphosphonate to cells with abundant and active Pho84 at the plasma membrane causes enhanced internalization of the Pho84 protein. Altogether, these observations suggest that the Pho84 transporter is regulated not only at the transcriptional level but also by a direct molecule-sensing mechanism at the protein level.
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Affiliation(s)
- James R Pratt
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm, Sweden
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Persson BL, Lagerstedt JO, Pratt JR, Pattison-Granberg J, Lundh K, Shokrollahzadeh S, Lundh F. Regulation of phosphate acquisition in Saccharomyces cerevisiae. Curr Genet 2003; 43:225-44. [PMID: 12740714 DOI: 10.1007/s00294-003-0400-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2003] [Revised: 04/05/2003] [Accepted: 04/08/2003] [Indexed: 01/08/2023]
Abstract
Membrane transport systems active in cellular inorganic phosphate (P(i)) acquisition play a key role in maintaining cellular P(i) homeostasis, independent of whether the cell is a unicellular microorganism or is contained in the tissue of a higher eukaryotic organism. Since unicellular eukaryotes such as yeast interact directly with the nutritious environment, regulation of P(i) transport is maintained solely by transduction of nutrient signals across the plasma membrane. The individual yeast cell thus recognizes nutrients that can act as both signals and sustenance. The present review provides an overview of P(i) acquisition via the plasma membrane P(i) transporters of Saccharomyces cerevisiae and the regulation of internal P(i) stores under the prevailing P(i) status.
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Affiliation(s)
- Bengt L Persson
- Department of Chemistry and Biomedical Science, Kalmar University, P.O. Box 905, 39182, Kalmar, Sweden.
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Lagerstedt JO, Zvyagilskaya R, Pratt JR, Pattison-Granberg J, Kruckeberg AL, Berden JA, Persson BL. Mutagenic and functional analysis of the C-terminus of Saccharomyces cerevisiae Pho84 phosphate transporter. FEBS Lett 2002; 526:31-7. [PMID: 12208499 DOI: 10.1016/s0014-5793(02)03109-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A widely accepted mechanism for selective degradation of plasma membrane proteins is via ubiquitination and/or phosphorylation events. Such a regulated degradation has previously been suggested to rely on the presence of a specific SINNDAKSS sequence within the protein. Modification of a partly conserved SINNDAKSS-like sequence in the C-terminal tail of the Pho84 phosphate transporter, in combination with C-terminal fusion of green fluorescent protein or a MYC epitope, were used to evaluate the presence of this sequence and its role in the regulated degradation. The functional Pho84 mutants in which this SINNDAKSS-like sequence was altered or truncated were subjected to degradation like that of the wild type, suggesting that degradation of the Pho84 protein is regulated by factors other than properties of this sequence.
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Affiliation(s)
- Jens O Lagerstedt
- Department of Biochemistry and Biophysics, Wallenberg Laboratory, Stockholm University, 106 91 Stockholm, Sweden
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Berhe A, Zvyagilskaya R, Lagerstedt JO, Pratt JR, Persson BL. Properties of the cysteine-less Pho84 phosphate transporter of Saccharomyces cerevisiae. Biochem Biophys Res Commun 2001; 287:837-42. [PMID: 11573939 DOI: 10.1006/bbrc.2001.5664] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The derepressible Pho84 high-affinity phosphate permease of Saccharomyces cerevisiae, encoded by the PHO84 gene belongs to a family of phosphate:proton symporters (PHS). The protein contains 12 native cysteine residues of which five are predicted to be located in putative transmembrane regions III, VI, VIII, IX, and X, and the remaining seven in the hydrophilic domains of the protein. Here we report on the construction of a Pho84 transporter devoid of cysteine residues (C-less) in which all 12 native residues were replaced with serines using PCR mutagenesis and the functional consequences of this. Our results clearly demonstrate that the C-less Pho84 variant is able to support growth of yeast cells to the same extent as the wild-type Pho84 and is stably expressed under derepressible conditions and is fully active in proton-coupled phosphate transport across the yeast plasma membrane.
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Affiliation(s)
- A Berhe
- Department of Biochemistry and Biophysics, Wallenberg Laboratory, S-106 91 Stockholm, Sweden
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