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Iannotta D, A A, Lai A, Nair S, Koifman N, Lappas M, Salomon C, Wolfram J. Chemically-Induced Lipoprotein Breakdown for Improved Extracellular Vesicle Purification. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2307240. [PMID: 38100284 DOI: 10.1002/smll.202307240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/08/2023] [Indexed: 12/17/2023]
Abstract
Extracellular vesicles (EVs) are nanosized biomolecular packages involved in intercellular communication. EVs are released by all cells, making them broadly applicable as therapeutic, diagnostic, and mechanistic components in (patho)physiology. Sample purity is critical for correctly attributing observed effects to EVs and for maximizing therapeutic and diagnostic performance. Lipoprotein contaminants represent a major challenge for sample purity. Lipoproteins are approximately six orders of magnitude more abundant in the blood circulation and overlap in size, shape, and density with EVs. This study represents the first example of an EV purification method based on the chemically-induced breakdown of lipoproteins. Specifically, a styrene-maleic acid (SMA) copolymer is used to selectively breakdown lipoproteins, enabling subsequent size-based separation of the breakdown products from plasma EVs. The use of the polymer followed by tangential flow filtration or size-exclusion chromatography results in improved EV yield, preservation of EV morphology, increased EV markers, and reduced contaminant markers. SMA-based EV purification enables improved fluorescent labeling, reduces interactions with macrophages, and enhances accuracy, sensitivity, and specificity to detect EV biomarkers, indicating benefits for various downstream applications. In conclusion, SMA is a simple and effective method to improve the purity and yield of plasma-derived EVs, which favorably impacts downstream applications.
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Affiliation(s)
- Dalila Iannotta
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Amruta A
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Andrew Lai
- Translational Extracellular Vesicles in Obstetrics and Gynae-Oncology Group, Faculty of Medicine, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Soumyalekshmi Nair
- Translational Extracellular Vesicles in Obstetrics and Gynae-Oncology Group, Faculty of Medicine, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Na'ama Koifman
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Martha Lappas
- University of Melbourne, Department of Obstetrics and Gynaecology, Australia, and Mercy Hospital for Women, 163 Studley Road, Heidelberg, Victoria, 3084, Australia
| | - Carlos Salomon
- Translational Extracellular Vesicles in Obstetrics and Gynae-Oncology Group, Faculty of Medicine, University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, The University of Queensland, Brisbane, QLD, 4029, Australia
| | - Joy Wolfram
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
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2
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Nakamura Y, Kulkarni NN, Takahashi T, Alimohamadi H, Dokoshi T, Liu E, Shia M, Numata T, Luo EW, Gombart AF, Yang X, Secrest P, Gordts PL, Tsimikas S, Wong GC, Gallo RL. Increased LL37 in psoriasis and other inflammatory disorders promotes LDL uptake and atherosclerosis. J Clin Invest 2024; 134:e172578. [PMID: 38194294 PMCID: PMC10904043 DOI: 10.1172/jci172578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 01/05/2024] [Indexed: 01/10/2024] Open
Abstract
Patients with chronic inflammatory disorders such as psoriasis have an increased risk of cardiovascular disease and elevated levels of LL37, a cathelicidin host defense peptide that has both antimicrobial and proinflammatory properties. To explore whether LL37 could contribute to the risk of heart disease, we examined its effects on lipoprotein metabolism and show that LL37 enhanced LDL uptake in macrophages through the LDL receptor (LDLR), scavenger receptor class B member 1 (SR-B1), and CD36. This interaction led to increased cytosolic cholesterol in macrophages and changes in expression of lipid metabolism genes consistent with increased cholesterol uptake. Structure-function analysis and synchrotron small-angle x-ray scattering showed structural determinants of the LL37-LDL complex that underlie its ability to bind its receptors and promote uptake. This function of LDL uptake is unique to cathelicidins from humans and some primates and was not observed with cathelicidins from mice or rabbits. Notably, Apoe-/- mice expressing LL37 developed larger atheroma plaques than did control mice, and a positive correlation between plasma LL37 and oxidized phospholipid on apolipoprotein B (OxPL-apoB) levels was observed in individuals with cardiovascular disease. These findings provide evidence that LDL uptake can be increased via interaction with LL37 and may explain the increased risk of cardiovascular disease associated with chronic inflammatory disorders.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Adrian F. Gombart
- Linus Pauling Institute, Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
| | | | - Patrick Secrest
- Department of Medicine, Division of Endocrinology and Metabolism, and
| | - Philip L.S.M. Gordts
- Department of Medicine, Division of Endocrinology and Metabolism, and
- Glycobiology Research and Training Center, UCSD, La Jolla, California, USA
| | | | - Gerard C.L. Wong
- Department of Bioengineering, UCLA, Los Angeles, California, USA
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3
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Nencini R, Regnier MLG, Backlund SM, Mantzari E, Dunn CD, Ollila OHS. Probing the dynamic landscape of peptides in molecular assemblies by synergized NMR experiments and MD simulations. Commun Chem 2024; 7:28. [PMID: 38351219 PMCID: PMC10864328 DOI: 10.1038/s42004-024-01115-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/25/2024] [Indexed: 02/16/2024] Open
Abstract
Peptides or proteins containing small biomolecular aggregates, such as micelles, bicelles, droplets and nanodiscs, are pivotal in many fields ranging from structural biology to pharmaceutics. Monitoring dynamics of such systems has been limited by the lack of experimental methods that could directly detect their fast (picosecond to nanosecond) timescale dynamics. Spin relaxation times from NMR experiments are sensitive to such motions, but their interpretation for biomolecular aggregates is not straightforward. Here we show that the dynamic landscape of peptide-containing molecular assemblies can be determined by a synergistic combination of solution state NMR experiments and molecular dynamics (MD) simulations. Solution state NMR experiments are straightforward to implement without an excessive amount of sample, while direct combination of spin relaxation data to MD simulations enables interpretation of dynamic landscapes of peptides and other aggregated molecules. To demonstrate this, we interpret NMR data from transmembrane, peripheral, and tail anchored peptides embedded in micelles. Our results indicate that peptides and detergent molecules do not rotate together as a rigid body, but peptides rotate in a viscous medium composed of detergent micelle. Spin relaxation times also provide indirect information on peptide conformational ensembles. This work gives new perspectives on peptide dynamics in complex biomolecular assemblies.
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Affiliation(s)
- Ricky Nencini
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | | | - Sofia M Backlund
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | | | - Cory D Dunn
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - O H Samuli Ollila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
- VTT Technical Research Centre of Finland, Espoo, Finland.
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4
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Machado LO, Reis D, Figueiredo Neto AM. The Soret coefficient of human low-density lipoprotein in solution: a thermophilic behavior. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:124. [PMID: 38060052 DOI: 10.1140/epje/s10189-023-00377-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
Thermodiffusion, or Soret effect, is the physical phenomenon of matter gradients originated by the migration of chemical species induced by thermal gradients. Thermodiffusion has been widely applied in the study of colloidal suspensions. In this study, we investigate the termodiffusion behavior of low-density lipoprotein (LDL) particles, by the Soret coefficient measurement. It is a new approach to studies of plasma lipoproteins. The experimental work was based on thermal- and Soret-lens effects. These effects were induced by laser irradiation of the samples, at two different time scales, in a Z-scan setup. LDL samples were analyzed under physiological conditions, notedly, ionic strength and pH, and at different temperatures. Temperature dependence of Soret coefficient showed a slight decrease in the absolute value of this coefficient, as a function of temperature increasing. However, its sign does not change at the temperatures investigated (15, 22.5 and 37.5 °C). The results show that LDL particles exhibit thermophilic behavior. The origin of this thermophilic behavior is not yet completely understood. We discuss some aspects that can be related with the Soret effect in LDL samples.
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Affiliation(s)
| | - Dennys Reis
- Institute of Physics, University of São Paulo, São Paulo, Brazil
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5
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Cisse A, Desfosses A, Stainer S, Kandiah E, Traore DAK, Bezault A, Schachner-Nedherer AL, Leitinger G, Hoerl G, Hinterdorfer P, Gutsche I, Prassl R, Peters J, Kornmueller K. Targeting structural flexibility in low density lipoprotein by integrating cryo-electron microscopy and high-speed atomic force microscopy. Int J Biol Macromol 2023; 252:126345. [PMID: 37619685 DOI: 10.1016/j.ijbiomac.2023.126345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/08/2023] [Accepted: 08/13/2023] [Indexed: 08/26/2023]
Abstract
Low-density lipoprotein (LDL) plays a crucial role in cholesterol metabolism. Responsible for cholesterol transport from the liver to the organs, LDL accumulation in the arteries is a primary cause of cardiovascular diseases, such as atherosclerosis. This work focuses on the fundamental question of the LDL molecular structure, as well as the topology and molecular motions of apolipoprotein B-100 (apo B-100), which is addressed by single-particle cryo-electron microscopy (cryo-EM) and high-speed atomic force microscopy (HS-AFM). Our results suggest a revised model of the LDL core organization with respect to the cholesterol ester (CE) arrangement. In addition, a high-density region close to the flattened poles could be identified, likely enriched in free cholesterol. The most remarkable new details are two protrusions on the LDL surface, attributed to the protein apo B-100. HS-AFM adds the dimension of time and reveals for the first time a highly dynamic direct description of LDL, where we could follow large domain fluctuations of the protrusions in real time. To tackle the inherent flexibility and heterogeneity of LDL, the cryo-EM maps are further assessed by 3D variability analysis. Our study gives a detailed explanation how to approach the intrinsic flexibility of a complex system comprising lipids and protein.
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Affiliation(s)
- Aline Cisse
- Université Grenoble Alpes, CNRS, LiPhy, Grenoble, France; Institut Laue-Langevin, Grenoble, France
| | - Ambroise Desfosses
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Sarah Stainer
- Department of Experimental Applied Biophysics, Johannes Kepler University Linz, Linz, Austria
| | | | - Daouda A K Traore
- Institut Laue-Langevin, Grenoble, France; Faculté de Pharmacie, Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Bamako, Mali; Faculty of Natural Sciences, School of Life Sciences, Keele University, Staffordshire, UK
| | - Armel Bezault
- Institut Européen de Chimie et Biologie, UAR3033/US001, Université de Bordeaux, CNRS, INSERM 2, Pessac, France; Structural Image Analysis Unit, Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, CNRS UMR3528, Paris, France
| | - Anna-Laurence Schachner-Nedherer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical Physics and Biophysics Division, Medical University of Graz, Graz, Austria
| | - Gerd Leitinger
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Division of Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Gerd Hoerl
- Otto Loewi Research Center, Physiological Chemistry, Medical University of Graz, Graz, Austria
| | - Peter Hinterdorfer
- Department of Experimental Applied Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - Irina Gutsche
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Ruth Prassl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical Physics and Biophysics Division, Medical University of Graz, Graz, Austria
| | - Judith Peters
- Université Grenoble Alpes, CNRS, LiPhy, Grenoble, France; Institut Laue-Langevin, Grenoble, France; Institut Universitaire de France, France.
| | - Karin Kornmueller
- Institut Laue-Langevin, Grenoble, France; Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical Physics and Biophysics Division, Medical University of Graz, Graz, Austria.
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6
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Larrea-Sebal A, Jebari-Benslaiman S, Galicia-Garcia U, Jose-Urteaga AS, Uribe KB, Benito-Vicente A, Martín C. Predictive Modeling and Structure Analysis of Genetic Variants in Familial Hypercholesterolemia: Implications for Diagnosis and Protein Interaction Studies. Curr Atheroscler Rep 2023; 25:839-859. [PMID: 37847331 PMCID: PMC10618353 DOI: 10.1007/s11883-023-01154-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2023] [Indexed: 10/18/2023]
Abstract
PURPOSE OF REVIEW Familial hypercholesterolemia (FH) is a hereditary condition characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C), which increases the risk of cardiovascular disease if left untreated. This review aims to discuss the role of bioinformatics tools in evaluating the pathogenicity of missense variants associated with FH. Specifically, it highlights the use of predictive models based on protein sequence, structure, evolutionary conservation, and other relevant features in identifying genetic variants within LDLR, APOB, and PCSK9 genes that contribute to FH. RECENT FINDINGS In recent years, various bioinformatics tools have emerged as valuable resources for analyzing missense variants in FH-related genes. Tools such as REVEL, Varity, and CADD use diverse computational approaches to predict the impact of genetic variants on protein function. These tools consider factors such as sequence conservation, structural alterations, and receptor binding to aid in interpreting the pathogenicity of identified missense variants. While these predictive models offer valuable insights, the accuracy of predictions can vary, especially for proteins with unique characteristics that might not be well represented in the databases used for training. This review emphasizes the significance of utilizing bioinformatics tools for assessing the pathogenicity of FH-associated missense variants. Despite their contributions, a definitive diagnosis of a genetic variant necessitates functional validation through in vitro characterization or cascade screening. This step ensures the precise identification of FH-related variants, leading to more accurate diagnoses. Integrating genetic data with reliable bioinformatics predictions and functional validation can enhance our understanding of the genetic basis of FH, enabling improved diagnosis, risk stratification, and personalized treatment for affected individuals. The comprehensive approach outlined in this review promises to advance the management of this inherited disorder, potentially leading to better health outcomes for those affected by FH.
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Affiliation(s)
- Asier Larrea-Sebal
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain
- Department of Molecular Biophysics, Biofisika Institute, University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC), 48940, Leioa, Spain
- Fundación Biofisika Bizkaia, 48940, Leioa, Spain
| | - Shifa Jebari-Benslaiman
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain
- Department of Molecular Biophysics, Biofisika Institute, University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC), 48940, Leioa, Spain
| | - Unai Galicia-Garcia
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain
- Department of Molecular Biophysics, Biofisika Institute, University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC), 48940, Leioa, Spain
| | - Ane San Jose-Urteaga
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain
| | - Kepa B Uribe
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain
| | - Asier Benito-Vicente
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain
- Department of Molecular Biophysics, Biofisika Institute, University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC), 48940, Leioa, Spain
| | - César Martín
- Department of Biochemistry and Molecular Biology, Universidad del País Vasco UPV/EHU, 48080, Bilbao, Spain.
- Department of Molecular Biophysics, Biofisika Institute, University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC), 48940, Leioa, Spain.
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7
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Wang R, Zhang X, Feng K, Zeng W, Wu J, Sun D, Lu Z, Feng H, Di L. Nanotechnologies meeting natural sources: Engineered lipoproteins for precise brain disease theranostics. Asian J Pharm Sci 2023; 18:100857. [PMID: 37953874 PMCID: PMC10637878 DOI: 10.1016/j.ajps.2023.100857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 09/03/2023] [Accepted: 09/08/2023] [Indexed: 11/14/2023] Open
Abstract
Biological nanotechnologies have provided considerable opportunities in the management of malignancies with delicate design and negligible toxicity, from preventive and diagnostic to therapeutic fields. Lipoproteins, because of their inherent blood-brain barrier permeability and lesion-homing capability, have been identified as promising strategies for high-performance theranostics of brain diseases. However, the application of natural lipoproteins remains limited owing to insufficient accumulation and complex purification processes, which can be critical for individual therapeutics and clinical translation. To address these issues, lipoprotein-inspired nano drug-delivery systems (nano-DDSs), which have been learned from nature, have been fabricated to achieve synergistic drug delivery involving site-specific accumulation and tractable preparation with versatile physicochemical functions. In this review, the barriers in brain disease treatment, advantages of state-of-the-art lipoprotein-inspired nano-DDSs, and bio-interactions of such nano-DDSs are highlighted. Furthermore, the characteristics and advanced applications of natural lipoproteins and tailor-made lipoprotein-inspired nano-DDSs are summarized. Specifically, the key designs and current applications of lipoprotein-inspired nano-DDSs in the field of brain disease therapy are intensively discussed. Finally, the current challenges and future perspectives in the field of lipoprotein-inspired nano-DDSs combined with other vehicles, such as exosomes, cell membranes, and bacteria, are discussed.
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Affiliation(s)
- Ruoning Wang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Xinru Zhang
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Kuanhan Feng
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Wei Zeng
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Jie Wu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Danni Sun
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Ziyi Lu
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Hao Feng
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
| | - Liuqing Di
- School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China
- Jiangsu Provincial TCM Engineering Technology Research Center of High Efficient Drug Delivery System, Nanjing 210023, China
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8
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Korpanty J, Wang C, Gianneschi NC. Upper critical solution temperature polymer assemblies via variable temperature liquid phase transmission electron microscopy and liquid resonant soft X-ray scattering. Nat Commun 2023; 14:3441. [PMID: 37301949 DOI: 10.1038/s41467-023-38781-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 05/15/2023] [Indexed: 06/12/2023] Open
Abstract
Here, we study the upper critical solution temperature triggered phase transition of thermally responsive poly(ethylene glycol)-block-poly(ethylene glycol) methyl ether acrylate-co-poly(ethylene glycol) phenyl ether acrylate-block-polystyrene nanoassemblies in isopropanol. To gain mechanistic insight into the organic solution-phase dynamics of the upper critical solution temperature polymer, we leverage variable temperature liquid-cell transmission electron microscopy correlated with variable temperature liquid resonant soft X-ray scattering. Heating above the upper critical solution temperature triggers a reduction in particle size and a morphological transition from a spherical core shell particle with a complex, multiphase core to a micelle with a uniform core and Gaussian polymer chains attached to the surface. These correlated solution phase methods, coupled with mass spectral validation and modeling, provide unique insight into these thermoresponsive materials. Moreover, we detail a generalizable workflow for studying complex, solution-phase nanomaterials via correlative methods.
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Affiliation(s)
- Joanna Korpanty
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, IL, 60208, USA
| | - Cheng Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Nathan C Gianneschi
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, IL, 60208, USA.
- Department of Materials Science & Engineering, Northwestern University, Evanston, IL, 60208, USA.
- Department of Biomedical Engineering and Department of Pharmacology, Northwestern University, Evanston, IL, 60208, USA.
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9
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Klein S, Golani G, Lolicato F, Lahr C, Beyer D, Herrmann A, Wachsmuth-Melm M, Reddmann N, Brecht R, Hosseinzadeh M, Kolovou A, Makroczyova J, Peterl S, Schorb M, Schwab Y, Brügger B, Nickel W, Schwarz US, Chlanda P. IFITM3 blocks influenza virus entry by sorting lipids and stabilizing hemifusion. Cell Host Microbe 2023; 31:616-633.e20. [PMID: 37003257 DOI: 10.1016/j.chom.2023.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 11/15/2022] [Accepted: 03/06/2023] [Indexed: 04/03/2023]
Abstract
Interferon-induced transmembrane protein 3 (IFITM3) inhibits the entry of numerous viruses through undefined molecular mechanisms. IFITM3 localizes in the endosomal-lysosomal system and specifically affects virus fusion with target cell membranes. We found that IFITM3 induces local lipid sorting, resulting in an increased concentration of lipids disfavoring viral fusion at the hemifusion site. This increases the energy barrier for fusion pore formation and the hemifusion dwell time, promoting viral degradation in lysosomes. In situ cryo-electron tomography captured IFITM3-mediated arrest of influenza A virus membrane fusion. Observation of hemifusion diaphragms between viral particles and late endosomal membranes confirmed hemifusion stabilization as a molecular mechanism of IFITM3. The presence of the influenza fusion protein hemagglutinin in post-fusion conformation close to hemifusion sites further indicated that IFITM3 does not interfere with the viral fusion machinery. Collectively, these findings show that IFITM3 induces lipid sorting to stabilize hemifusion and prevent virus entry into target cells.
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Affiliation(s)
- Steffen Klein
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Gonen Golani
- BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany; Institute for Theoretical Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany; Department of Physics, University of Helsinki, Helsinki, Finland
| | - Carmen Lahr
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Daniel Beyer
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Alexia Herrmann
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Moritz Wachsmuth-Melm
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Nina Reddmann
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Romy Brecht
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Mehdi Hosseinzadeh
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Androniki Kolovou
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Jana Makroczyova
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Sarah Peterl
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Martin Schorb
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Yannick Schwab
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Britta Brügger
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Ulrich S Schwarz
- BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany; Institute for Theoretical Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Petr Chlanda
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany; BioQuant Center for Quantitative Biology, Heidelberg University, 69120 Heidelberg, Germany.
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10
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Different Pathways of Cellular Cholesterol Efflux. Cell Biochem Biophys 2022; 80:471-481. [PMID: 35737216 DOI: 10.1007/s12013-022-01081-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/13/2022] [Indexed: 12/22/2022]
Abstract
Cholesterol efflux is the first and rate-limiting step of reverse cholesterol transport (RCT) from peripheric cells to the liver. The involvement of high-density lipoprotein (HDL) in RCT determines the atheroprotective properties of HDL. Cholesterol efflux from different membrane pools includes both passive and energy-dependent processes. The first type of route consists of cholesterol desorption from the cell membrane into the unstirred layer adjacent to the cell surface and diffusion in the water phase. Moreover, the selective uptake and facilitated diffusion of cholesterol and cholesteryl ester molecules through the hydrophobic tunnel in the scavenger receptor BI molecule does not require energy consumption. The second type of route includes active cholesterol export by the ATP-binding cassette transporters A1 (ABCA1) and G1 (ABCG1). Several cholesterol acceptors specifically bind cholesterol and phospholipid molecules, and cholesterol binding to the albumin molecule, which acts as a shuttle, significantly increases cholesterol movement between acceptors and red blood cells, thus functioning as a sink for cholesterol. Cholesterol and phospholipid molecules effluxed from macrophages by ABCA1 are accepted exclusively by the lipid-free apolipoprotein apoA-I, which is the major protein moiety of HDL, whereas those effluxed by ABCG1 are accepted by HDL. ABCA1- and ABCG1-mediated cholesterol transport, together with cholesterol diffusion, largely determine cholesterol turnover at the physiological level of intracellular cholesterol. However, at cholesterol overload, ABCA1-mediated efflux prevails over other routes. The exchange of apoA-I between lipid-free and lipid-associated states and the synergism of nascent and mature HDL contribute to cholesterol efflux efficiency. Moreover, extracellular cholesterol deposits and microvesicles may be involved in RCT.
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11
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Iwaki T, Arakawa T, Sandoval-Cooper MJ, Smith DL, Donahue D, Ploplis VA, Umemura K, Castellino FJ. Plasminogen Deficiency Significantly Reduces Vascular Wall Disease in a Murine Model of Type IIa Hypercholesterolemia. Biomedicines 2021; 9:biomedicines9121832. [PMID: 34944648 PMCID: PMC8698429 DOI: 10.3390/biomedicines9121832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 12/02/2022] Open
Abstract
The fibrinolytic system has been implicated in the genesis and progression of atherosclerosis. It has been reported that a plasminogen (Pg) deficiency (Plg−/−) exacerbates the progression of atherosclerosis in Apoe−/− mice. However, the manner in which Plg functions in a low-density lipoprotein-cholesterol (LDL-C)-driven model has not been evaluated. To characterize the effect of Pg in an LDL-C-driven model, mice with a triple deficiency of the LDL-receptor (LDLr), along with the active component (apobec1) of the apolipoprotein B editosome complex, and Pg (L−/−/A−/−/Plg−/−), were generated. Atherosclerotic plaque formation was severely retarded in the absence of Pg. In vitro studies demonstrated that LDL uptake by macrophages was enhanced by plasmin (Pm), whereas circulating levels of LDL were enhanced, relative to L−/−/A−/− mice, and VLDL synthesis was suppressed. These results indicated that clearance of lipoproteins in the absence of LDLr may be regulated by Pg/Pm. Conclusions: The results from this study indicate that Pg exacerbates atherosclerosis in an LDL-C model of atherosclerosis and also plays a role in lipoprotein modification and clearance. Therefore, controlling the Pg system on macrophages to prevent foam cell formation would be a novel therapeutic approach.
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Affiliation(s)
- Takayuki Iwaki
- The W. M. Keck Center for Transgene Research, The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.S.-C.); (D.L.S.); (D.D.); (V.A.P.); (F.J.C.)
- Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.A.); (K.U.)
- Correspondence: ; Tel.: +81-53-435-2271
| | - Tomohiro Arakawa
- Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.A.); (K.U.)
| | - Mayra J. Sandoval-Cooper
- The W. M. Keck Center for Transgene Research, The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.S.-C.); (D.L.S.); (D.D.); (V.A.P.); (F.J.C.)
| | - Denise L. Smith
- The W. M. Keck Center for Transgene Research, The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.S.-C.); (D.L.S.); (D.D.); (V.A.P.); (F.J.C.)
| | - Deborah Donahue
- The W. M. Keck Center for Transgene Research, The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.S.-C.); (D.L.S.); (D.D.); (V.A.P.); (F.J.C.)
| | - Victoria A. Ploplis
- The W. M. Keck Center for Transgene Research, The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.S.-C.); (D.L.S.); (D.D.); (V.A.P.); (F.J.C.)
| | - Kazuo Umemura
- Department of Pharmacology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.A.); (K.U.)
| | - Francis J. Castellino
- The W. M. Keck Center for Transgene Research, The Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (M.J.S.-C.); (D.L.S.); (D.D.); (V.A.P.); (F.J.C.)
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12
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Korpanty J, Parent LR, Hampu N, Weigand S, Gianneschi NC. Thermoresponsive polymer assemblies via variable temperature liquid-phase transmission electron microscopy and small angle X-ray scattering. Nat Commun 2021; 12:6568. [PMID: 34772926 PMCID: PMC8589985 DOI: 10.1038/s41467-021-26773-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/15/2021] [Indexed: 11/19/2022] Open
Abstract
Herein, phase transitions of a class of thermally-responsive polymers, namely a homopolymer, diblock, and triblock copolymer, were studied to gain mechanistic insight into nanoscale assembly dynamics via variable temperature liquid-cell transmission electron microscopy (VT-LCTEM) correlated with variable temperature small angle X-ray scattering (VT-SAXS). We study thermoresponsive poly(diethylene glycol methyl ether methacrylate) (PDEGMA)-based block copolymers and mitigate sample damage by screening electron flux and solvent conditions during LCTEM and by evaluating polymer survival via post-mortem matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). Our multimodal approach, utilizing VT-LCTEM with MS validation and VT-SAXS, is generalizable across polymeric systems and can be used to directly image solvated nanoscale structures and thermally-induced transitions. Our strategy of correlating VT-SAXS with VT-LCTEM provided direct insight into transient nanoscale intermediates formed during the thermally-triggered morphological transformation of a PDEGMA-based triblock. Notably, we observed the temperature-triggered formation and slow relaxation of core-shell particles with complex microphase separation in the core by both VT-SAXS and VT-LCTEM.
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Affiliation(s)
- Joanna Korpanty
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, IL, 60208, USA
| | - Lucas R Parent
- Innovation Partnership Building, University of Connecticut, Storrs, CT, 06269, USA
| | - Nicholas Hampu
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, IL, 60208, USA
| | - Steven Weigand
- DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) Synchrotron Research Center, Northwestern University, Argonne, IL, 60208, USA
| | - Nathan C Gianneschi
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, Simpson Querrey Institute, Northwestern University, Evanston, IL, 60208, USA.
- Department of Materials Science & Engineering, Northwestern University, Evanston, IL, 60208, USA.
- Department of Biomedical Engineering and Department of Pharmacology, Northwestern University, Evanston, IL, 60208, USA.
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13
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Transfer Investigations of Lipophilic Drugs from Lipid Nanoemulsions to Lipophilic Acceptors: Contributing Effects of Cholesteryl Esters and Albumin as Acceptor Structures. Pharmaceuticals (Basel) 2021; 14:ph14090865. [PMID: 34577565 PMCID: PMC8471859 DOI: 10.3390/ph14090865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/21/2022] Open
Abstract
When studying the release of poorly water-soluble drugs from colloidal drug delivery systems designed for intravenous administration, the release media should preferentially contain lipophilic components that represent the physiological acceptors present in vivo. In this study, the effect of different acceptor structures was investigated by comparing the transfer of fenofibrate, retinyl acetate, and orlistat from trimyristin nanoemulsion droplets into lipid-containing hydrogel particles, as well as to bovine serum albumin (BSA). A nanodispersion based on trimyristin and cholesteryl nonanoate was incorporated into the hydrogel particles (mean diameter ~40 µm) in order to mimic the composition of lipoproteins. The course of transfer observed utilizing the lipid-containing hydrogel particles as an acceptor was in relation to the lipophilicity of the drugs: the higher the logP value, the slower the transfer. There was no detectable amount of the drugs transferred to BSA in liquid solution, demonstrating clearly that albumin alone does not contribute substantially as acceptor for the lipophilic drugs under investigation in this study. In contrast, cholesteryl nonanoate contributes to a much greater extent. However, in all cases, the partition equilibrium of the drugs under investigation was in favor of the trimyristin emulsion droplets.
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14
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Jeong YH, Ahn T, Yu W, Lee SM. Cholesterol-Functionalized Linear/Brush Block Copolymers for Metal-Incorporated Nanostructures with Modulated Core Density and Enhanced Self-Assembly Efficiency. ACS Macro Lett 2021; 10:492-497. [PMID: 35549233 DOI: 10.1021/acsmacrolett.1c00112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Metal-mediated self-assembly of chelating double-hydrophilic block copolymer has become a facile preparation strategy of great importance for the metal-chelated hybrid nanostructures. Herein, we present a delicate control over the morphology regulation of metal-chelated nanostructures by a terminal modification of polymer building blocks with mesogenic cholesterol. Such a molecular design motif at an end of chelating linear/brush-type block copolymer imparts not only additional hydrophobicity for enhanced cohesive force to facilitate the metal-mediated self-assembly, but also significant morphological alteration of a metal-chelated core that otherwise generally forms a spherical interior with cholesterol-free block copolymers. The presence of cholesterol entities localized at the central core further allows for the density modulation of the final PtII-chelated nanostructures while maintaining the colloidal stability, comparable to that of the cholesterol-free nanoparticles in physiological conditions. This metal-mediated assembly strategy with modified polymer building blocks can provide a potential platform for the delivery of inorganic agents.
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Affiliation(s)
- Yun-Ho Jeong
- Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 14662, Korea
| | - Taekyung Ahn
- Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 14662, Korea
| | - Wonjeong Yu
- Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 14662, Korea
| | - Sang-Min Lee
- Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 14662, Korea
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15
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Jakubauskas D, Jansen M, Lyngsø J, Cheng Y, Pedersen JS, Cárdenas M. Toward reliable low-density lipoprotein ultrastructure prediction in clinical conditions: A small-angle X-ray scattering study on individuals with normal and high triglyceride serum levels. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 31:102318. [PMID: 33091569 DOI: 10.1016/j.nano.2020.102318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/23/2020] [Accepted: 10/05/2020] [Indexed: 10/23/2022]
Abstract
Atherosclerosis is the main killer in the west and therefore a major health challenge today. Total serum cholesterol and lipoprotein concentrations, used as clinical markers, fail to predict the majority of cases, especially between the risk scale extremes, due to the high complexity in lipoprotein structure and composition. In particular, low-density lipoprotein (LDL) plays a key role in atherosclerosis development, with LDL size being a parameter considered for determining the risk for cardiovascular diseases. Determining LDL size and structural parameters is challenging to address experimentally under physiological-like conditions. This article describes the biochemistry and ultrastructure of normolipidemic and hypertriglyceridemic LDL fractions and subfractions using small-angle X-ray scattering. Our results conclude that LDL particles of hypertriglyceridemic compared to healthy individuals 1) have lower LDL core melting temperature, 2) have lower cholesteryl ester ordering in their core, 3) are smaller, rounder and more spherical below melting temperature, and 4) their protein-containing shell is thinner above melting temperature.
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Affiliation(s)
- Dainius Jakubauskas
- Biofilms - Research center for Biointerfaces, Dept. of Biomedical Science, Faculty of Health and Society, Malmo University, Malmo, Sweden.
| | - Martin Jansen
- Institute of Clinical Chemistry and Laboratory Medicine, Medical Centre, University of Freiburg, Freiburg im Breisgau, Germany.
| | - Jeppe Lyngsø
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
| | - Yuanji Cheng
- Department of Materials Science and Applied Mathematics, Faculty of Technology and Society, Malmo University, Malmo, Sweden.
| | - Jan Skov Pedersen
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
| | - Marité Cárdenas
- Biofilms - Research center for Biointerfaces, Dept. of Biomedical Science, Faculty of Health and Society, Malmo University, Malmo, Sweden.
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16
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Busatto S, Walker SA, Grayson W, Pham A, Tian M, Nesto N, Barklund J, Wolfram J. Lipoprotein-based drug delivery. Adv Drug Deliv Rev 2020; 159:377-390. [PMID: 32791075 PMCID: PMC7747060 DOI: 10.1016/j.addr.2020.08.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/01/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023]
Abstract
Lipoproteins (LPs) are circulating heterogeneous nanoparticles produced by the liver and intestines. LPs play a major role in the transport of dietary and endogenous lipids to target cells through cell membrane receptors or cell surface-bound lipoprotein lipase. The stability, biocompatibility, and selective transport of LPs make them promising delivery vehicles for various therapeutic and imaging agents. This review discusses isolation, manufacturing, and drug loading techniques used for LP-based drug delivery, as well as recent applications for diagnosis and treatment of cancer, atherosclerosis, and other life-threatening diseases.
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Affiliation(s)
- Sara Busatto
- Department of Biochemistry and Molecular Biology, Department of Physiology and Biomedical Engineering, Department of Transplantation, Mayo Clinic, Jacksonville, FL 32224, USA.
| | - Sierra A Walker
- Department of Biochemistry and Molecular Biology, Department of Physiology and Biomedical Engineering, Department of Transplantation, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Whisper Grayson
- Department of Biology, University of North Florida, Jacksonville, FL 32224, USA
| | - Anthony Pham
- Department of Biochemistry and Molecular Biology, Department of Physiology and Biomedical Engineering, Department of Transplantation, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Ming Tian
- Department of Biochemistry and Molecular Biology, Department of Physiology and Biomedical Engineering, Department of Transplantation, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Nicole Nesto
- Department of Biology, University of North Florida, Jacksonville, FL 32224, USA
| | - Jacqueline Barklund
- Department of Biology, University of North Florida, Jacksonville, FL 32224, USA
| | - Joy Wolfram
- Department of Biochemistry and Molecular Biology, Department of Physiology and Biomedical Engineering, Department of Transplantation, Mayo Clinic, Jacksonville, FL 32224, USA; Department of Biology, University of North Florida, Jacksonville, FL 32224, USA; Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA.
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17
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Abstract
Lipid droplets are cytoplasmic microscale organelles involved in energy homeostasis and handling of cellular lipids and proteins. The core structure is mainly composed of two kinds of neutral lipids, triglycerides and cholesteryl esters, which are coated by a phospholipid monolayer and proteins. Despite the liquid crystalline nature of cholesteryl esters, the connection between the lipid composition and physical states is poorly understood. Here, we present a universal intracellular phase diagram of lipid droplets, semiquantitatively consistent with the in vitro phase diagram, and reveal that cholesterol esters cause the liquid-liquid crystal phase transition under near-physiological conditions. We moreover combine in vivo and in vitro studies, together with the theory of confined liquid crystals, to suggest that the radial molecular alignments in the liquid crystallized lipid droplets are caused by an anchoring force at the droplet surface. Our findings on the phase transition of lipid droplets and resulting molecular organization contribute to a better understanding of their biological functions and diseases.
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18
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Baumstark D, Kremer W, Boettcher A, Schreier C, Sander P, Schmitz G, Kirchhoefer R, Huber F, Kalbitzer HR. 1H NMR spectroscopy quantifies visibility of lipoproteins, subclasses, and lipids at varied temperatures and pressures. J Lipid Res 2019; 60:1516-1534. [PMID: 31239285 PMCID: PMC6718440 DOI: 10.1194/jlr.m092643] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/18/2019] [Indexed: 01/27/2023] Open
Abstract
NMR-based quantification of human lipoprotein (sub)classes is a powerful high-throughput method for medical diagnostics. We evaluated select proton NMR signals of serum lipoproteins for elucidating the physicochemical features and the absolute NMR visibility of their lipids. We separated human lipoproteins of different subclasses by ultracentrifugation and analyzed them by 1H NMR spectroscopy at different temperatures (283-323 K) and pressures (0.1-200 MPa). In parallel, we determined the total lipid content by extraction with chloroform/methanol. The visibility of different lipids in the 1H NMR spectra strongly depends on temperature and pressure: it increases with increasing temperatures but decreases with increasing pressures. Even at 313 K, only part of the lipoprotein is detected quantitatively. In LDL and in HDL subclasses HDL2 and HDL3, only 39%, 62%, and 90% of the total cholesterol and only 73%, 70%, and 87% of the FAs are detected, respectively. The choline head groups show visibilities of 43%, 75%, and 87% for LDL, HDL2, and HDL3, respectively. The description of the NMR visibility of lipid signals requires a minimum model of three different compartments, A, B, and C. The thermodynamic analysis of compartment B leads to melting temperatures between 282 K and 308 K and to enthalpy differences that vary for the different lipoproteins as well as for the reporter groups selected. In summary, we describe differences in NMR visibility of lipoproteins and variations in biophysical responses of functional groups that are crucial for the accuracy of absolute NMR quantification.
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Affiliation(s)
- Daniela Baumstark
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany
| | - Werner Kremer
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany
| | - Alfred Boettcher
- Institute of Clinical Chemistry and Laboratory Medicine University Hospital Regensburg, 93053 Regensburg, Germany
| | - Christina Schreier
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany; numares AG, 93053 Regensburg, Germany
| | - Paul Sander
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory Medicine University Hospital Regensburg, 93053 Regensburg, Germany
| | | | | | - Hans Robert Kalbitzer
- Institute of Biophysics and Physical BiochemistryUniversity of Regensburg, 93040 Regensburg, Germany; Centre of Magnetic Resonance in Chemistry and Biomedicine University of Regensburg, 93040 Regensburg, Germany.
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19
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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20
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Liu J, Wu H, Huang C, Lei D, Zhang M, Xie W, Li J, Ren G. Optimized Negative-Staining Protocol for Lipid-Protein Interactions Investigated by Electron Microscopy. Methods Mol Biol 2019; 2003:163-173. [PMID: 31218618 PMCID: PMC6817366 DOI: 10.1007/978-1-4939-9512-7_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A large number of proteins are capable of inserting themselves into lipids, and interacting with membranes, such as transmembrane proteins and apolipoproteins. Insights into the lipid-protein interactions are important in understanding biological processes, and the structure of proteins at the lipid binding stage can help identify their roles and critical functions. Previously, such structural determination was challenging to obtain because the traditional methods, such as X-ray crystallography, are unable to capture the conformational and compositional heterogeneity of protein-lipid complexes. Electron microscopy (EM) is an alternative approach to determining protein structures and visualizing lipid-protein interactions directly, and negative-staining (OpNS), a subset of EM techniques, is a rapid, frequently used qualitative approach. The concern, however, is that current NS protocols often generate artifacts with lipid-related proteins, such as rouleaux formation from lipoproteins. To overcome this artifact formation, Ren and his colleagues have refined early NS protocols, and developed an optimized NS protocol that validated by comparing images of lipoproteins from cryo-electron microscopy (cryo-EM). This optimized NS protocol produces "near native-state" particle images and high contrast images of the protein in its native lipid-binding state, which can be used to create higher-quality three-dimensional (3D) reconstruction by single-particle analysis and electron tomography (e.g. IPET). This optimized protocol is thus a promising hands-on approach for examining the structure of proteins at their lipid-binding status.
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Affiliation(s)
- Jianfang Liu
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Hao Wu
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Computer Science, College of Information Science and Technology, Beijing Normal University, Beijing, China
| | - Changyu Huang
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Dongsheng Lei
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Meng Zhang
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Wei Xie
- State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou, Guangdong, China
- Center for Cellular and Structural Biology, The Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jinping Li
- Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA, USA
| | - Gang Ren
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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21
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Lehofer B, Golub M, Kornmueller K, Kriechbaum M, Martinez N, Nagy G, Kohlbrecher J, Amenitsch H, Peters J, Prassl R. High Hydrostatic Pressure Induces a Lipid Phase Transition and Molecular Rearrangements in Low-Density Lipoprotein Nanoparticles. PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION : MEASUREMENT AND DESCRIPTION OF PARTICLE PROPERTIES AND BEHAVIOR IN POWDERS AND OTHER DISPERSE SYSTEMS 2018; 35:1800149. [PMID: 30283212 PMCID: PMC6166783 DOI: 10.1002/ppsc.201800149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Indexed: 06/08/2023]
Abstract
Low-density lipoproteins (LDL) are natural lipid transporter in human plasma whose chemically modified forms contribute to the progression of atherosclerosis and cardiovascular diseases accounting for a vast majority of deaths in westernized civilizations. For the development of new treatment strategies, it is important to have a detailed picture of LDL nanoparticles on a molecular basis. Through the combination of X-ray and neutron small-angle scattering (SAS) techniques with high hydrostatic pressure (HHP) this study describes structural features of normolipidemic, triglyceride-rich and oxidized forms of LDL. Due to the different scattering contrasts for X-rays and neutrons, information on the effects of HHP on the internal structure determined by lipid rearrangements and changes in particle shape becomes accessible. Independent pressure and temperature variations provoke a phase transition in the lipid core domain. With increasing pressure an inter-related anisotropic deformation and flattening of the particle are induced. All LDL nanoparticles maintain their structural integrity even at 3000 bar and show a reversible response toward pressure variations. The present work depicts the complementarity of pressure and temperature as independent thermodynamic parameters and introduces HHP as a tool to study molecular assembling and interaction processes in distinct lipoprotein particles in a nondestructive manner.
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Affiliation(s)
- Bernhard Lehofer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging Biophysics, Medical University of Graz, Neue Stiftingtalstraße 6/IV, 8010 Graz, Austria
| | - Maksym Golub
- Institut Laue-Langevin, 71 avenue des Martyrs, 38044 Grenoble, France; Univ. Grenoble Alpes, CNRS + CEA, IBS, 38000 Grenoble, France
| | - Karin Kornmueller
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging Biophysics, Medical University of Graz, Neue Stiftingtalstraße 6/IV, 8010 Graz, Austria
| | - Manfred Kriechbaum
- Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Nicolas Martinez
- Institut Laue-Langevin, 71 avenue des Martyrs, 38044 Grenoble, France; Univ. Grenoble Alpes, CNRS + CEA, IBS, 38000 Grenoble, France
| | - Gergely Nagy
- Paul Scherrer Institut, 5232 Villigen, Switzerland; Wigner Research Centre for Physics, 1121 Budapest, Hungary; European Spallation Source ERIC, 22363 Lund, Sweden
| | | | - Heinz Amenitsch
- Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Judith Peters
- Institut Laue-Langevin, 71 avenue des Martyrs, 38044 Grenoble, France; Univ. Grenoble Alpes, CNRS, LiPhy, 38000 Grenoble, France
| | - Ruth Prassl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging Biophysics, Medical University of Graz, Neue Stiftingtalstraße 6/IV, 8010 Graz, Austria
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22
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Lewandowska H, Męczyńska-Wielgosz S, Sikorska K, Sadło J, Dudek J, Kruszewski M. LDL dinitrosyl iron complex: A new transferrin-independent route for iron delivery in hepatocytes. Biofactors 2018; 44:192-201. [PMID: 29399922 DOI: 10.1002/biof.1412] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/09/2017] [Accepted: 12/29/2017] [Indexed: 12/14/2022]
Abstract
In view of the interrelations between NO, Fe, and LDL in the cardiovascular system it appears interesting to find out, if the lipoprotein particles undergo the process of iron-nitrosylation, commonly observed for other proteins and what is the biological fate of iron-nitrosylated LDL particles. Iron-nitrosylated LDL preparation containing Fe(NO)2 motif (DNICLDL) was obtained and characterized for the first time. In order to test its interactions with potential target cells, DNICLDL was administered to the hepatoma HepG2 cells. The effects were referred to those induced by native LDL (nLDL) and oxidized LDL (oxLDL) particles. DNICLDL administration considerably increased total iron content in the studied cell line, but did not influence the level of calcein-chelatable ions. DNICLDL was found to be low toxic to cells. The study suggests that DNICLDL might be a potential transducer of iron. © 2017 BioFactors, 44(2):192-201, 2018.
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Affiliation(s)
- Hanna Lewandowska
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str, Warsaw, 03-195, Poland
| | | | - Katarzyna Sikorska
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str, Warsaw, 03-195, Poland
| | - Jarosław Sadło
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str, Warsaw, 03-195, Poland
| | - Jakub Dudek
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str, Warsaw, 03-195, Poland
| | - Marcin Kruszewski
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str, Warsaw, 03-195, Poland
- Faculty of Medicine, University of Information Technology and Management in Rzeszów, ul. Sucharskiego 2, Rzeszów, 35-225, Poland
- Department of Molecular Biology and Translational Research, Institute of Rural Health, Jaczewskiego 2, Lublin, 20-090, Poland
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23
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Baldwin PR, Tan YZ, Eng ET, Rice WJ, Noble AJ, Negro CJ, Cianfrocco MA, Potter CS, Carragher B. Big data in cryoEM: automated collection, processing and accessibility of EM data. Curr Opin Microbiol 2017; 43:1-8. [PMID: 29100109 DOI: 10.1016/j.mib.2017.10.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/27/2017] [Accepted: 10/09/2017] [Indexed: 11/24/2022]
Abstract
The scope and complexity of cryogenic electron microscopy (cryoEM) data has greatly increased, and will continue to do so, due to recent and ongoing technical breakthroughs that have led to much improved resolutions for macromolecular structures solved using this method. This big data explosion includes single particle data as well as tomographic tilt series, both generally acquired as direct detector movies of ∼10-100 frames per image or per tilt-series. We provide a brief survey of the developments leading to the current status, and describe existing cryoEM pipelines, with an emphasis on the scope of data acquisition, methods for automation, and use of cloud storage and computing.
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Affiliation(s)
- Philip R Baldwin
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA
| | - Yong Zi Tan
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Edward T Eng
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA
| | - William J Rice
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA
| | - Alex J Noble
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA
| | - Carl J Negro
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA
| | - Michael A Cianfrocco
- Life Sciences Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Clinton S Potter
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Bridget Carragher
- The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, 89 Convent Ave, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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24
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Ninham BW, Larsson K, Lo Nostro P. Two sides of the coin. Part 2. Colloid and surface science meets real biointerfaces. Colloids Surf B Biointerfaces 2017; 159:394-404. [PMID: 28822288 DOI: 10.1016/j.colsurfb.2017.07.090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/07/2017] [Accepted: 07/31/2017] [Indexed: 12/23/2022]
Abstract
Part 1 revisited developments in lipid and surfactant self assembly over the past 40 years [1]. New concepts emerged. Here we explore how these developments can be used to make sense of and bring order to a range of complex biological phenomena. Together with Part 1, this contribution is a fundamental revision of intuition at the boundaries of Colloid Science and Biological interfaces from a perspective of nearly 50 years. We offer new insights on a unified treatment of self assembly of lipids, surfactants and proteins in the light of developments presented in Part 1. These were in the enabling disciplines in molecular forces, hydration, oil and electrolyte specificity; and in the role of non Euclidean geometries-across the whole gammut of physical, colloid and surface chemistry, biophysics and membrane biology and medicine. It is where the early founders of the cell theory of biology and the physiologists expected advances to occur as D'Arcy Thompson predicted us 100 years ago.
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Affiliation(s)
- Barry W Ninham
- Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia; Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Firenze, Italy
| | - Kåre Larsson
- Camurus Lipid Research Foundation, Ideon Science Park, 22370 Lund, Sweden
| | - Pierandrea Lo Nostro
- Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Firenze, Italy; Fondazione Prof. Enzo Ferroni-Onlus, 50019 Sesto Fiorentino, Firenze, Italy.
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25
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Peters J, Martinez N, Lehofer B, Prassl R. Low-density lipoproteins investigated under high hydrostatic pressure by elastic incoherent neutron scattering. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2017; 40:68. [PMID: 28733727 PMCID: PMC5589066 DOI: 10.1140/epje/i2017-11558-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/11/2017] [Indexed: 05/14/2023]
Abstract
Human low-density lipoprotein (LDL) is a highly complex nano-particle built up of various lipid classes and a single large protein moiety (apoB-100) owning essential physiological functions in the human body. Besides its vital role as a supplier of cholesterol and fat for peripheral tissues and cells, it is also a known key player in the formation of atherosclerosis. Due to these important roles in physiology and pathology the elucidation of structural and dynamical details is of great interest. In the current study we drew a broader picture of LDL dynamics using elastic incoherent neutron scattering (EINS) as a function of specified temperature and pressure points. We not only investigated a normolipidemic LDL sample, but also a triglyceride-rich and an oxidized one to mimic pathologic conditions as found under hyperlipidemic conditions or in atherosclerotic plaques, respectively. We could show that pressure has a significant effect on atomic motions in modified forms of LDL, whereas the normolipidemic sample seems to cope much better with high-pressure conditions irrespective of temperature. These findings might be explained by the altered lipid composition, which is either caused through elevated triglyceride content or modifications through lipid peroxidation.
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Affiliation(s)
- J Peters
- Univ. Grenoble Alpes, LiPhy, F-38044, Grenoble, France
- Institut Laue Langevin, F-38000, Grenoble, France
| | - N Martinez
- Institut Laue Langevin, F-38000, Grenoble, France
- Univ. Grenoble Alpes, IBS, F-38000, Grenoble, France
| | - B Lehofer
- Institute of Biophysics, Medical University of Graz, A-8010, Graz, Austria
| | - R Prassl
- Institute of Biophysics, Medical University of Graz, A-8010, Graz, Austria.
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26
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Lara S, Alnasser F, Polo E, Garry D, Lo Giudice MC, Hristov DR, Rocks L, Salvati A, Yan Y, Dawson KA. Identification of Receptor Binding to the Biomolecular Corona of Nanoparticles. ACS NANO 2017; 11:1884-1893. [PMID: 28112950 DOI: 10.1021/acsnano.6b07933] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Biomolecules adsorbed on nanoparticles are known to confer a biological identity to nanoparticles, mediating the interactions with cells and biological barriers. However, how these molecules are presented on the particle surface in biological milieu remains unclear. The central aim of this study is to identify key protein recognition motifs and link them to specific cell-receptor interactions. Here, we employed an immuno-mapping technique to quantify epitope presentations of two major proteins in the serum corona, low-density lipoprotein and immunoglobulin G. Combining with a purpose-built receptor expression system, we show that both proteins present functional motifs to allow simultaneous recognition by low-density lipoprotein receptor and Fc-gamma receptor I of the corona. Our results suggest that the "labeling" of nanoparticles by biomolecular adsorption processes allows for multiple pathways in biological processes in which they may be "mistaken" for endogenous objects, such as lipoproteins, and exogenous ones, such as viral infections.
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Affiliation(s)
- Sandra Lara
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Fatima Alnasser
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Ester Polo
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - David Garry
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Maria Cristina Lo Giudice
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Delyan R Hristov
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Louise Rocks
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Anna Salvati
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Yan Yan
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
| | - Kenneth A Dawson
- Centre for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin , Belfield, Dublin 4, Ireland
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27
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Maric S, Lind TK, Lyngsø J, Cárdenas M, Pedersen JS. Modeling Small-Angle X-ray Scattering Data for Low-Density Lipoproteins: Insights into the Fatty Core Packing and Phase Transition. ACS NANO 2017; 11:1080-1090. [PMID: 28048943 DOI: 10.1021/acsnano.6b08089] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Atherosclerosis and its clinical consequences are the leading cause of death in the western hemisphere. While many studies throughout the last decades have aimed at understanding the disease, the clinical markers in use today still fail to accurately predict the risks. The role of the current main clinical indicator, low density lipoprotein (LDL), in depositing fat to the vessel wall is believed to be the onset of the process. However, many subfractions of the LDL, which differ both in structure and composition, are present in the blood and among different individuals. Understanding the relationship between LDL structure and composition is key to unravel the specific role of various LDL components in the development and/or prevention of atherosclerosis. Here, we describe a model for analyzing small-angle X-ray scattering data for rapid and robust structure determination for the LDL. The model not only gives the overall structure but also the particular internal layering of the fats inside the LDL core. Thus, the melting of the LDL can be followed in situ as a function of temperature for samples extracted from healthy human patients and purified using a double protocol based on ultracentrifugation and size-exclusion chromatography. The model provides information on: (i) the particle-specific melting temperature of the core lipids, (ii) the structural organization of the core fats inside the LDL, (iii) the overall shape of the particle, and (iv) the flexibility and overall conformation of the outer protein/hydrophilic layer at a given temperature as governed by the organization of the core. The advantage of this method over other techniques such as cryo-TEM is the possibility of in situ experiments under near-physiological conditions which can be performed relatively fast (minutes at home source, seconds at synchrotron). This approach now allows the monitoring of structural changes in the LDL upon different stresses from the environment, such as changes in temperature, oxidation, or external agents used or currently in development against atherosclerotic plaque build-up and which are targeting the LDL.
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Affiliation(s)
- Selma Maric
- Biofilms- Research Center for Biointerfaces, Dept. of Biomedical Science, Faculty of Health and Society, Malmö University , Malmö 20506, Sweden
| | - Tania Kjellerup Lind
- Biofilms- Research Center for Biointerfaces, Dept. of Biomedical Science, Faculty of Health and Society, Malmö University , Malmö 20506, Sweden
| | - Jeppe Lyngsø
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , 8000 Aarhus, Denmark
| | - Marité Cárdenas
- Biofilms- Research Center for Biointerfaces, Dept. of Biomedical Science, Faculty of Health and Society, Malmö University , Malmö 20506, Sweden
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , 8000 Aarhus, Denmark
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28
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Glossmann HH, Lutz OMD. Torpor: The Rise and Fall of 3-Monoiodothyronamine from Brain to Gut-From Gut to Brain? Front Endocrinol (Lausanne) 2017; 8:118. [PMID: 28620354 PMCID: PMC5450037 DOI: 10.3389/fendo.2017.00118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 05/16/2017] [Indexed: 12/12/2022] Open
Abstract
3-Monoiodothyronamine (T1AM), first isolated from rat brain, is reported to be an endogenous, rapidly acting metabolite of thyroxine. One of its numerous effects is the induction of a "torpor-like" state in experimental animals. A critical analysis of T1AM, to serve as an endogenous cryogen, is given. The proposed biosynthetic pathway for formation of T1AM, which includes deiodinases and ornithine decarboxylase in the upper intestinum, is an unusual one. To reach the brain via systemic circulation, enterohepatic recycling and passage through the liver may occur. The possible role of gut microbiota is discussed. T1AM concentrations in human serum, measured by a specific monoclonal assay are up to three orders of magnitude higher compared to values obtained by MS/MS technology. The difference is explained by the presence of a high-affinity binder for T1AM (Apolipoprotein B-100) in serum, which permits the immunoassay to measure the total concentration of the analyte but limits MS/MS technology to detect only the unbound (free) analyte, a view, which is contested here.
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Affiliation(s)
- Hartmut H. Glossmann
- Institut für Biochemische Pharmakologie, Innsbruck, Austria
- *Correspondence: Hartmut H. Glossmann,
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29
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Gordon SM, Pourmousa M, Sampson M, Sviridov D, Islam R, Perrin BS, Kemeh G, Pastor RW, Remaley AT. Identification of a novel lipid binding motif in apolipoprotein B by the analysis of hydrophobic cluster domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:135-145. [PMID: 27814978 DOI: 10.1016/j.bbamem.2016.10.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/11/2016] [Accepted: 10/27/2016] [Indexed: 02/05/2023]
Abstract
Apolipoprotein B (apoB) is a large amphipathic protein that is the structural scaffold for the formation of several classes of lipoproteins involved in lipid transport throughout the body. The goal of the present study was to identify specific domains in the apoB sequence that contribute to its lipid binding properties. A sequence analysis algorithm was developed to identify stretches of hydrophobic amino acids devoid of charged amino acids, which are referred to as hydrophobic cluster domains (HCDs). This analysis identified 78 HCDs in apoB with hydrophobic stretches ranging from 6 to 26 residues. Each HCD was analyzed in silico for secondary structure and lipid binding properties, and a subset was synthesized for experimental evaluation. One HCD peptide, B38, showed high affinity binding to both isolated HDL and LDL, and could exchange between lipoproteins. All-atom molecular dynamics simulations indicate that B38 inserts 3.7Å below the phosphate plane of the bilayer. B38 forms an unusual α-helix with a broad hydrophobic face and polar serine and threonine residues on the opposite face. Based on this structure, we hypothesized that B38 could efflux cholesterol from cells. B38 showed a 12-fold greater activity than the 5A peptide, a bihelical Class A amphipathic helix (EC50 of 0.2658 vs. 3.188μM; p<0.0001), in promoting cholesterol efflux from ABCA1 expressing BHK-1 cells. In conclusion, we have identified novel domains within apoB that contribute to its lipid biding properties. Additionally, we have discovered a unique amphipathic helix design for efficient ABCA1-specific cholesterol efflux.
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Affiliation(s)
- Scott M Gordon
- Lipoprotein Metabolism Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Mohsen Pourmousa
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Maureen Sampson
- Lipoprotein Metabolism Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Denis Sviridov
- Lipoprotein Metabolism Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Rafique Islam
- Lipoprotein Metabolism Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA; School of Systems Biology, George Mason University, Fairfax, VA, USA
| | - B Scott Perrin
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Georgina Kemeh
- Lipoprotein Metabolism Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Alan T Remaley
- Lipoprotein Metabolism Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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30
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Yu Y, Kuang YL, Lei D, Zhai X, Zhang M, Krauss RM, Ren G. Polyhedral 3D structure of human plasma very low density lipoproteins by individual particle cryo-electron tomography1. J Lipid Res 2016; 57:1879-1888. [PMID: 27538822 PMCID: PMC5036368 DOI: 10.1194/jlr.m070375] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Indexed: 12/21/2022] Open
Abstract
Human VLDLs assembled in the liver and secreted into the circulation supply energy to peripheral tissues. VLDL lipolysis yields atherogenic LDLs and VLDL remnants that strongly correlate with CVD. Although the composition of VLDL particles has been well-characterized, their 3D structure is elusive because of their variations in size, heterogeneity in composition, structural flexibility, and mobility in solution. Here, we employed cryo-electron microscopy and individual-particle electron tomography to study the 3D structure of individual VLDL particles (without averaging) at both below and above their lipid phase transition temperatures. The 3D reconstructions of VLDL and VLDL bound to antibodies revealed an unexpected polyhedral shape, in contrast to the generally accepted model of a spherical emulsion-like particle. The smaller curvature of surface lipids compared with HDL may also reduce surface hydrophobicity, resulting in lower binding affinity to the hydrophobic distal end of the N-terminal β-barrel domain of cholesteryl ester transfer protein (CETP) compared with HDL. The directional binding of CETP to HDL and VLDL may explain the function of CETP in transferring TGs and cholesteryl esters between these particles. This first visualization of the 3D structure of VLDL could improve our understanding of the role of VLDL in atherogenesis.
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Affiliation(s)
- Yadong Yu
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Yu-Lin Kuang
- Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Dongsheng Lei
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Xiaobo Zhai
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Meng Zhang
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Ronald M Krauss
- Atherosclerosis Research, Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Gang Ren
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
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31
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Punicalagin Induces Serum Low-Density Lipoprotein Influx to Macrophages. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:7124251. [PMID: 27516832 PMCID: PMC4969581 DOI: 10.1155/2016/7124251] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 05/11/2016] [Accepted: 05/31/2016] [Indexed: 02/03/2023]
Abstract
High levels of circulating low-density lipoprotein (LDL) are a primary initiating event in the development of atherosclerosis. Recently, the antiatherogenic effect of polyphenols has been shown to be exerted via a mechanism unrelated to their antioxidant capacity and to stem from their interaction with specific intracellular or plasma proteins. In this study, we investigated the interaction of the main polyphenol in pomegranate, punicalagin, with apolipoprotein B-100 (ApoB100) that surrounds LDL. Punicalagin bound to ApoB100 at low concentrations (0.25–4 μM). Upon binding, it induced LDL influx to macrophages in a concentration-dependent manner, up to 2.5-fold. In contrast, another polyphenol which binds to ApoB100, glabridin, did not affect LDL influx. We further showed that LDL influx occurs specifically through the LDL receptor, with LDL then accumulating in the cell cytoplasm. Taken together with the findings of Aviram et al., 2000, that pomegranate juice and punicalagin induce plasma LDL removal and inhibit macrophage cholesterol synthesis and accumulation, our results suggest that, upon binding, punicalagin stimulates LDL influx to macrophages, thus reducing circulating cholesterol levels.
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32
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Lu M, Gursky O. Aggregation and fusion of low-density lipoproteins in vivo and in vitro. Biomol Concepts 2015; 4:501-18. [PMID: 25197325 DOI: 10.1515/bmc-2013-0016] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Low-density lipoproteins (LDLs, also known as 'bad cholesterol') are the major carriers of circulating cholesterol and the main causative risk factor of atherosclerosis. Plasma LDLs are 20- to 25-nm nanoparticles containing a core of cholesterol esters surrounded by a phospholipid monolayer and a single copy of apolipoprotein B (550 kDa). An early sign of atherosclerosis is the accumulation of LDL-derived lipid droplets in the arterial wall. According to the widely accepted 'response-to-retention hypothesis', LDL binding to the extracellular matrix proteoglycans in the arterial intima induces hydrolytic and oxidative modifications that promote LDL aggregation and fusion. This enhances LDL uptake by the arterial macrophages and triggers a cascade of pathogenic responses that culminate in the development of atherosclerotic lesions. Hence, LDL aggregation, fusion, and lipid droplet formation are important early steps in atherogenesis. In vitro, a variety of enzymatic and nonenzymatic modifications of LDL can induce these reactions and thereby provide useful models for their detailed analysis. Here, we summarize current knowledge of the in vivo and in vitro modifications of LDLs leading to their aggregation, fusion, and lipid droplet formation; outline the techniques used to study these reactions; and propose a molecular mechanism that underlies these pro-atherogenic processes. Such knowledge is essential in identifying endogenous and exogenous factors that can promote or prevent LDL aggregation and fusion in vivo and to help establish new potential therapeutic targets to decelerate or even block these pathogenic reactions.
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Affiliation(s)
- Mengxiao Lu
- Department of Physiology and Biophysics, Boston University School of Medicine, W321, 700 Albany Street, Boston, MA 02118, USA.
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33
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Dichlberger A, Schlager S, Kovanen PT, Schneider WJ. Lipid droplets in activated mast cells - a significant source of triglyceride-derived arachidonic acid for eicosanoid production. Eur J Pharmacol 2015; 785:59-69. [PMID: 26164793 DOI: 10.1016/j.ejphar.2015.07.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/28/2015] [Accepted: 07/07/2015] [Indexed: 12/17/2022]
Abstract
Mast cells are potent effectors of immune reactions and key players in various inflammatory diseases such as atherosclerosis, asthma, and rheumatoid arthritis. The cellular defense response of mast cells represents a unique and powerful system, where external signals can trigger cell activation resulting in a stimulus-specific and highly coordinated release of a plethora of bioactive mediators. The arsenal of mediators encompasses preformed molecules stored in cytoplasmic secretory granules, as well as newly synthesized proteinaceous and lipid mediators. The release of mediators occurs in strict chronological order and requires proper coordination between the endomembrane system and various enzymatic machineries. For the generation of lipid mediators, cytoplasmic lipid droplets have been shown to function as a major intracellular pool of arachidonic acid, the precursor for eicosanoid biosynthesis. Recent studies have revealed that not only phospholipids in mast cell membranes, but also triglycerides in mast cell lipid droplets are a substrate source for eicosanoid formation. The present review summarizes current knowledge about mast cell lipid droplet biology, and discusses expansions and challenges of traditional mechanistic models for eicosanoid production.
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Affiliation(s)
- Andrea Dichlberger
- Wihuri Research Institute, Biomedicum Helsinki 1, Haartmaninkatu 8, 00290 Helsinki, Finland; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria.
| | - Stefanie Schlager
- Medical University of Graz, Institute of Molecular Biology and Biochemistry, Harrachgasse 21, 8010 Graz, Austria; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria
| | - Petri T Kovanen
- Wihuri Research Institute, Biomedicum Helsinki 1, Haartmaninkatu 8, 00290 Helsinki, Finland; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria
| | - Wolfgang J Schneider
- Wihuri Research Institute, Biomedicum Helsinki 1, Haartmaninkatu 8, 00290 Helsinki, Finland; Medical University of Graz, Institute of Molecular Biology and Biochemistry, Harrachgasse 21, 8010 Graz, Austria; Medical University of Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Dr. Bohrgasse 9/2, 1030 Vienna, Austria
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Amyloid-Forming Properties of Human Apolipoproteins: Sequence Analyses and Structural Insights. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 855:175-211. [PMID: 26149931 DOI: 10.1007/978-3-319-17344-3_8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Apolipoproteins are protein constituents of lipoproteins that transport cholesterol and fat in circulation and are central to cardiovascular health and disease. Soluble apolipoproteins can transiently dissociate from the lipoprotein surface in a labile free form that can misfold, potentially leading to amyloid disease. Misfolding of apoA-I, apoA-II, and serum amyloid A (SAA) causes systemic amyloidoses, apoE4 is a critical risk factor in Alzheimer's disease, and apolipoprotein misfolding is also implicated in cardiovascular disease. To explain why apolipoproteins are over-represented in amyloidoses, it was proposed that the amphipathic α-helices, which form the lipid surface-binding motif in this protein family, have high amyloid-forming propensity. Here, we use 12 sequence-based bioinformatics approaches to assess amyloid-forming potential of human apolipoproteins and to identify segments that are likely to initiate β-aggregation. Mapping such segments on the available atomic structures of apolipoproteins helps explain why some of them readily form amyloid while others do not. Our analysis shows that nearly all amyloidogenic segments: (i) are largely hydrophobic, (ii) are located in the lipid-binding amphipathic α-helices in the native structures of soluble apolipoproteins, (iii) are predicted in both native α-helices and β-sheets in the insoluble apoB, and (iv) are predicted to form parallel in-register β-sheet in amyloid. Most of these predictions have been verified experimentally for apoC-II, apoA-I, apoA-II and SAA. Surprisingly, the rank order of the amino acid sequence propensity to form amyloid (apoB>apoA-II>apoC-II≥apoA-I, apoC-III, SAA, apoC-I>apoA-IV, apoA-V, apoE) does not correlate with the proteins' involvement in amyloidosis. Rather, it correlates directly with the strength of the protein-lipid association, which increases with increasing protein hydrophobicity. Therefore, the lipid surface-binding function and the amyloid-forming propensity are both rooted in apolipoproteins' hydrophobicity, suggesting that functional constraints make it difficult to completely eliminate pathogenic apolipoprotein misfolding. We propose that apolipoproteins have evolved protective mechanisms against misfolding, such as the sequestration of the amyloidogenic segments via the native protein-lipid and protein-protein interactions involving amphipathic α-helices and, in case of apoB, β-sheets.
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Ganini D, Mason RP. Absence of an effect of vitamin E on protein and lipid radical formation during lipoperoxidation of LDL by lipoxygenase. Free Radic Biol Med 2014; 76:61-8. [PMID: 25091900 PMCID: PMC4252844 DOI: 10.1016/j.freeradbiomed.2014.07.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 07/09/2014] [Accepted: 07/24/2014] [Indexed: 02/07/2023]
Abstract
Low-density lipoprotein (LDL) oxidation is the primary event in atherosclerosis, and LDL lipoperoxidation leads to modifications in apolipoprotein B-100 (apo B-100) and lipids. Intermediate species of lipoperoxidation are known to be able to generate amino acid-centered radicals. Thus, we hypothesized that lipoperoxidation intermediates induce protein-derived free radical formation during LDL oxidation. Using DMPO and immuno-spin trapping, we detected the formation of protein free radicals on LDL incubated with Cu(2+) or the soybean lipoxidase (LPOx)/phospholipase A2 (PLA2). With low concentrations of DMPO (1mM), Cu(2+) dose-dependently induced oxidation of LDL and easily detected apo B-100 radicals. Protein radical formation in LDL incubated with Cu(2+) showed maximum yields after 30 min. In contrast, the yields of apo B-100 radicals formed by LPOx/PLA2 followed a typical enzyme-catalyzed kinetics that was unaffected by DMPO concentrations of up to 50mM. Furthermore, when we analyzed the effect of antioxidants on protein radical formation during LDL oxidation, we found that ascorbate, urate, and Trolox dose-dependently reduced apo B-100 free radical formation in LDL exposed to Cu(2+). In contrast, Trolox was the only antioxidant that even partially protected LDL from LPOx/PLA2. We also examined the kinetics of lipid radical formation and protein radical formation induced by Cu(2+) or LPOx/PLA2 for LDL supplemented with α-tocopherol. In contrast to the potent antioxidant effect of α-tocopherol on the delay of LDL oxidation induced by Cu(2+), when we used the oxidizing system LPOx/PLA2, no significant protection was detected. The lack of protection of α-tocopherol on the apo B-100 and lipid free radical formation by LPOx may explain the failure of vitamin E as a cardiovascular protective agent for humans.
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Affiliation(s)
- Douglas Ganini
- Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
| | - Ronald P Mason
- Free Radical Metabolism Section, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Orekhov AN, Bobryshev YV, Sobenin IA, Melnichenko AA, Chistiakov DA. Modified low density lipoprotein and lipoprotein-containing circulating immune complexes as diagnostic and prognostic biomarkers of atherosclerosis and type 1 diabetes macrovascular disease. Int J Mol Sci 2014; 15:12807-41. [PMID: 25050779 PMCID: PMC4139876 DOI: 10.3390/ijms150712807] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 06/29/2014] [Accepted: 07/03/2014] [Indexed: 12/14/2022] Open
Abstract
In atherosclerosis; blood low-density lipoproteins (LDL) are subjected to multiple enzymatic and non-enzymatic modifications that increase their atherogenicity and induce immunogenicity. Modified LDL are capable of inducing vascular inflammation through activation of innate immunity; thus, contributing to the progression of atherogenesis. The immunogenicity of modified LDL results in induction of self-antibodies specific to a certain type of modified LDL. The antibodies react with modified LDL forming circulating immune complexes. Circulating immune complexes exhibit prominent immunomodulatory properties that influence atherosclerotic inflammation. Compared to freely circulating modified LDL; modified LDL associated with the immune complexes have a more robust atherogenic and proinflammatory potential. Various lipid components of the immune complexes may serve not only as diagnostic but also as essential predictive markers of cardiovascular events in atherosclerosis. Accumulating evidence indicates that LDL-containing immune complexes can also serve as biomarker for macrovascular disease in type 1 diabetes.
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Affiliation(s)
- Alexander N Orekhov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Yuri V Bobryshev
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Igor A Sobenin
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Alexandra A Melnichenko
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow 125315, Russia.
| | - Dimitry A Chistiakov
- Department of Medical Nanobiotechnology, Pirogov Russian State Medical University, Moscow 117997, Russia.
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Lancaster JL, Antonijevic T, Starobin JM. Ordering and stability in lipid droplets with applications to low-density lipoproteins. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:062708. [PMID: 25019815 DOI: 10.1103/physreve.89.062708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Indexed: 06/03/2023]
Abstract
In this article, we present a framework for investigating the order-disorder transition in lipid droplets using the standard Ising model. While a single lipid droplet is itself a complex system whose constituent cholesteryl esters each possesses many degrees of freedom, we present justification for using this effective approach to isolate the underlying physics. It is argued that the behavior of the esters confined within lipid droplets is significantly different from that of a bulk system of similar esters, which is adequately described by continuum mean-field theory in the thermodynamic limit. When the droplet's shell is modeled as an elastic membrane, a simple picture emerges for a transition between two ordered phases within the core which is tuned by the strength of interactions between the esters. Triglyceride concentration is proposed as a variable which strongly influences the strength of interactions between cholesteryl esters within droplets. The possible relevance of this mechanism to the well known atherogenic nature of small low-density lipoprotein particles is discussed in detail.
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Affiliation(s)
- Jarrett L Lancaster
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, 2907 E. Lee Street, Greensboro, North Carolina 27401, USA
| | - Todor Antonijevic
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, 2907 E. Lee Street, Greensboro, North Carolina 27401, USA
| | - Joseph M Starobin
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, 2907 E. Lee Street, Greensboro, North Carolina 27401, USA
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Abstract
This review highlights the protective roles of bilirubin against the atherosclerotic process. Bilirubin belongs to the superfamily of tetrapyrrolic compounds formed during heme catabolism. Although for decades bilirubin was considered to be a harmful waste product, recent epidemiologic studies have shown that serum bilirubin levels have consistently been inversely associated with cardiovascular disease (CVD), as well as cardiovascular risk factors such as metabolic syndrome and diabetes. These clinical studies are supported by in vitro and in vivo experimental data and have demonstrated that bilirubin not only has an ability to scavenge overproduced reactive oxygen species and inhibit vascular smooth muscle cell proliferation but, additionally, has anti-inflammatory effects. In this review, we will discuss the inverse association of serum bilirubin and CVD and cardiovascular risk factors established in various clinical studies. We also review detailed experimental studies about the effect of bilirubin on atherosclerotic processes. In vitro, animal and human studies have proved that bilirubin inhibits oxidation of cholesterol which is an important step of atherosclerosis. Bilirubin attenuates chemotactic activity of monocytes and strongly inhibits adhesion of leukocytes to venule and production of pro-inflammatory cytokines. Bilirubin has inhibited serum-driven smooth muscle cell cycle progression at the G1 phase. Lastly, we will discuss briefly the influence of bilirubin on lipoprotein composition and endothelial dysfunction.
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Affiliation(s)
- Seung Joo Kang
- Department of Internal Medicine, Healthcare Research Institute, Seoul National University, Hospital Healthcare System Gangnam Center , Seoul , Korea
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Fernández-Higuero JA, Salvador AM, Martín C, Milicua JCG, Arrondo JLR. Human LDL structural diversity studied by IR spectroscopy. PLoS One 2014; 9:e92426. [PMID: 24642788 PMCID: PMC3958539 DOI: 10.1371/journal.pone.0092426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/21/2014] [Indexed: 12/20/2022] Open
Abstract
Lipoproteins are responsible for cholesterol traffic in humans. Low density lipoprotein (LDL) delivers cholesterol from liver to peripheral tissues. A misleading delivery can lead to the formation of atherosclerotic plaques. LDL has a single protein, apoB-100, that binds to a specific receptor. It is known that the failure associated with a deficient protein-receptor binding leads to plaque formation. ApoB-100 is a large single lipid-associated polypeptide difficulting the study of its structure. IR spectroscopy is a technique suitable to follow the different conformational changes produced in apoB-100 because it is not affected by the size of the protein or the turbidity of the sample. We have analyzed LDL spectra of different individuals and shown that, even if there are not big structural changes, a different pattern in the intensity of the band located around 1617 cm−1 related with strands embedded in the lipid monolayer, can be associated with a different conformational rearrangement that could affect to a protein interacting region with the receptor.
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Affiliation(s)
- José A. Fernández-Higuero
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, Bilbao, Spain
| | - Ana M. Salvador
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, Bilbao, Spain
| | - Cesar Martín
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, Bilbao, Spain
| | - José Carlos G. Milicua
- Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, Bilbao, Spain
| | - José L. R. Arrondo
- Unidad de Biofísica (CSIC, UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, Bilbao, Spain
- * E-mail:
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Gao H, Wang Y, Chen C, Chen J, Wei Y, Cao S, Jiang X. Incorporation of lapatinib into core–shell nanoparticles improves both the solubility and anti-glioma effects of the drug. Int J Pharm 2014; 461:478-88. [DOI: 10.1016/j.ijpharm.2013.12.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Revised: 11/13/2013] [Accepted: 12/14/2013] [Indexed: 11/30/2022]
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Vindigni JD, Wien F, Giuliani A, Erpapazoglou Z, Tache R, Jagic F, Chardot T, Gohon Y, Froissard M. Fold of an oleosin targeted to cellular oil bodies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1881-8. [DOI: 10.1016/j.bbamem.2013.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 03/26/2013] [Accepted: 04/09/2013] [Indexed: 01/18/2023]
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Breyton C, Gabel F, Lethier M, Flayhan A, Durand G, Jault JM, Juillan-Binard C, Imbert L, Moulin M, Ravaud S, Härtlein M, Ebel C. Small angle neutron scattering for the study of solubilised membrane proteins. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:71. [PMID: 23852580 DOI: 10.1140/epje/i2013-13071-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/22/2013] [Accepted: 05/16/2013] [Indexed: 06/02/2023]
Abstract
Small angle neutron scattering (SANS) is a powerful technique for investigating association states and conformational changes of biological macromolecules in solution. SANS is of particular interest for the study of the multi-component systems, as membrane protein complexes, for which in vitro characterisation and structure determination are often difficult. This article details the important physical properties of surfactants in view of small angle neutron scattering studies and the interest to deuterate membrane proteins for contrast variation studies. We present strategies for the production of deuterated membrane proteins and methods for quality control. We then review some studies on membrane proteins, and focus on the strategies to overcome the intrinsic difficulty to eliminate homogeneously the detergent or surfactant signal for solubilised membrane proteins, or that of lipids for membrane proteins inserted in liposomes.
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Affiliation(s)
- Cécile Breyton
- Univ. Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027, Grenoble, France
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Melchior JT, Sawyer JK, Kelley KL, Shah R, Wilson MD, Hantgan RR, Rudel LL. LDL particle core enrichment in cholesteryl oleate increases proteoglycan binding and promotes atherosclerosis. J Lipid Res 2013; 54:2495-503. [PMID: 23804810 DOI: 10.1194/jlr.m039644] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several studies in humans and animals suggest that LDL particle core enrichment in cholesteryl oleate (CO) is associated with increased atherosclerosis. Diet enrichment with MUFAs enhances LDL CO content. Steroyl O-acyltransferase 2 (SOAT2) is the enzyme that catalyzes the synthesis of much of the CO found in LDL, and gene deletion of SOAT2 minimizes CO in LDL and protects against atherosclerosis. The purpose of this study was to test the hypothesis that the increased atherosclerosis associated with LDL core enrichment in CO results from an increased affinity of the LDL particle for arterial proteoglycans. ApoB-100-only Ldlr(-/-) mice with and without Soat2 gene deletions were fed diets enriched in either cis-MUFA or n-3 PUFA, and LDL particles were isolated. LDL:proteogylcan binding was measured using surface plasmon resonance. Particles with higher CO content consistently bound with higher affinity to human biglycan and the amount of binding was shown to be proportional to the extent of atherosclerosis of the LDL donor mice. The data strongly support the thesis that atherosclerosis was induced through enhanced proteoglycan binding of LDL resulting from LDL core CO enrichment.
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Affiliation(s)
- John T Melchior
- Department of Pathology, Section of Lipid Sciences, Wake Forest University School of Medicine, Winston Salem, NC, USA
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Abstract
LDs (lipid droplets) are metabolically highly active intracellular organelles. The lipid and protein profiles of LDs are cell-type-specific, and they undergo dynamic variation upon changes in the physiological state of a cell. It is well known that the main function of the LDs in adipocytes is to ensure energy supply and to maintain lipid homoeostasis in the body. In contrast, LDs in inflammatory cells have been implicated in eicosanoid biosynthesis, particularly under inflammatory conditions, thereby enabling them to regulate immune responses. Human mast cells are potent effector cells of the innate immune system, and the triacylglycerol (triglyceride) stores of their cytoplasmic LDs have been shown to contain large amounts of arachidonic acid, the main precursor of pro-inflammatory eicosanoids. In the present review, we discuss the current knowledge about the formation and function of LDs in inflammatory cells with specific emphasis on arachidonic acid and eicosanoid metabolism. On the basis of findings reported previously and our new observations, we propose a model in which lipolysis of LD-triacylglycerols provides arachidonic acid for lipid mediator generation in human mast cells.
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Borkotoky S, Meena CK, Khan MW, Murali A. Three dimensional electron microscopy and in silico tools for macromolecular structure determination. EXCLI JOURNAL 2013; 12:335-46. [PMID: 27092033 PMCID: PMC4827587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/14/2013] [Indexed: 12/02/2022]
Abstract
Recently, structural biology witnessed a major tool - electron microscopy - in solving the structures of macromolecules in addition to the conventional techniques, X-ray crystallography and nuclear magnetic resonance (NMR). Three dimensional transmission electron microscopy (3DTEM) is one of the most sophisticated techniques for structure determination of molecular machines. Known to give the 3-dimensional structures in its native form with literally no upper limit on size of the macromolecule, this tool does not need the crystallization of the protein. Combining the 3DTEM data with in silico tools, one can have better refined structure of a desired complex. In this review we are discussing about the recent advancements in three dimensional electron microscopy and tools associated with it.
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Affiliation(s)
- Subhomoi Borkotoky
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry-605014, India
| | - Chetan Kumar Meena
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry-605014, India
| | - Mohammad Wahab Khan
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry-605014, India
| | - Ayaluru Murali
- Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry-605014, India,*To whom correspondence should be addressed: Ayaluru Murali, Centre for Bioinformatics, School of Life Sciences, Pondicherry University, Puducherry-605014, India, E-mail:
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Gao H, Cao S, Chen C, Cao S, Yang Z, Pang Z, Xi Z, Pan S, Zhang Q, Jiang X. Incorporation of lapatinib into lipoprotein-like nanoparticles with enhanced water solubility and anti-tumor effect in breast cancer. Nanomedicine (Lond) 2013; 8:1429-42. [PMID: 23451915 DOI: 10.2217/nnm.12.180] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIM The poor water solubility of many active compounds is a serious deterrent to their use as commercial drugs. Lapatinib is a dual inhibitor of the EGF receptor and EGF receptor 2 approved by the US FDA to treat advanced breast cancer. This study prepares lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs) to enhance the water solubility and elevate the anti-tumor effect of lapatinib. MATERIALS & METHODS Bovine albumin was used to bind with lapatinib, and egg yolk lecithin was used to stabilize the conjugation of bovine albumin and lapatinib. The characteristics of LTNPs were evaluated by several experiments. Cell uptake and toxicity were performed on BT-474 cells. In vivo anti-tumor effect was performed on BT-474 xenograft-bearing mice. RESULTS LTNPs contained a lipid corona and a core of lapatinib and albumin. LTNPs could be effectively taken up by BT-474 cells and induced apoptosis. An in vivo study demonstrated that LTNPs could passively distribute into a tumor via the enhanced permeability and retention effect and induce anti-tumor activity in breast cancer. CONCLUSION The authors present a convenient nanoformulation with improved anti-tumor effect, which is a promising candidate for clinical trials.
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Affiliation(s)
- Huile Gao
- School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery, Ministry of Education & PLA, 826 Zhangheng Road, Shanghai 201203, China
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NMR spectroscopy of macrophages loaded with native, oxidized or enzymatically degraded lipoproteins. PLoS One 2013; 8:e56360. [PMID: 23457556 PMCID: PMC3574142 DOI: 10.1371/journal.pone.0056360] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/08/2013] [Indexed: 01/09/2023] Open
Abstract
Oxidized and enzymatically modified low-density lipoproteins (oxLDL and eLDL) play a key role in early stages of atherogenesis. Their uptake by recruited macrophages leads to endolysosomal phospholipidosis or foam cell formation, respectively, each of which is preceded by highly differential lipid restructuring processes. We applied 1H-NMR spectroscopy (NMRS) to elucidate these structural rearrangements both in consequence of lipoprotein modifications and following phagocytosis. Being specifically sensitive to the mobile lipid subset, NMRS of oxLDL and eLDL revealed a partial and total immobilization of lipids, respectively. NMRS of intact macrophages showed a sixfold increase in mobile lipids in case of loading with eLDL but no significant changes for oxLDL or native LDL. This finding reflected the disparate lipid storage in lipid droplets and in multilamellar endolysosomal clusters when loaded with either eLDL or oxLDL, respectively. Moreover, a significant shift of the degree of saturation towards mainly polyunsaturated fatty acid chains was found for the mobile lipid pool in eLDL-loaded macrophages. Additional analyses of lipid extracts by NMRS and mass spectrometry (MS) reflected these changes in lipid content and in fatty acid composition only partially. In summary, in-cell NMRS represents a unique lipidomics tool to investigate structural changes within the mobile lipid pool following atherogenic triggers that can be not detected by the analysis of lipid extracts by MS or NMRS.
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Garewal M, Zhang L, Ren G. Optimized negative-staining protocol for examining lipid-protein interactions by electron microscopy. Methods Mol Biol 2013; 974:111-8. [PMID: 23404274 PMCID: PMC10546916 DOI: 10.1007/978-1-62703-275-9_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A large number of proteins are capable of inserting themselves into lipids, and interacting with membranes, such as transmembrane proteins and apolipoproteins. Protein-lipid interactions have been identified as one of the keys in understanding biological processes, while the structure of proteins at the lipid-binding stage can provide evidence to help identify their roles and critical functions. However, structure determination of proteins at the lipid-binding stage is rather difficult, because conformational and compositional heterogeneities of the protein-lipid complexes are major barriers to unravel their structures using traditional methods, such as X-ray crystallography. Electron microscopy (EM) is an alternative approach to determine protein structure and has demonstrated a capability in visualizing lipid-protein interactions directly. Among various EM techniques, negative-staining (NS) is an easy, rapid, qualitative approach that is a well-established technique, frequently used in research laboratories. Conventional NS protocols, unfortunately, often generate artifacts with lipid-related proteins, such as the rouleau formation of lipoproteins. To overcome this artifact formation, Ren and his colleagues recently developed an optimized NS protocol that was validated by comparing images of lipoproteins from cryo-electron microscopy (cryo-EM). The optimized NS protocol could produce "near native-state" particle images and high contrast images of the protein in its lipid-binding state that is favorable for three-dimensional (3D) reconstruction by single-particle analysis and individual-particle electron tomography (IPET), suggesting this optimized protocol can be used widely to examine the structure of proteins at lipid-binding stage.
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Affiliation(s)
- Mark Garewal
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Mäkelä KM, Seppälä I, Hernesniemi JA, Lyytikäinen LP, Oksala N, Kleber ME, Scharnagl H, Grammer TB, Baumert J, Thorand B, Jula A, Hutri-Kähönen N, Juonala M, Laitinen T, Laaksonen R, Karhunen PJ, Nikus KC, Nieminen T, Laurikka J, Kuukasjärvi P, Tarkka M, Viik J, Klopp N, Illig T, Kettunen J, Ahotupa M, Viikari JSA, Kähönen M, Raitakari OT, Karakas M, Koenig W, Boehm BO, Winkelmann BR, März W, Lehtimäki T. Genome-wide association study pinpoints a new functional apolipoprotein B variant influencing oxidized low-density lipoprotein levels but not cardiovascular events: AtheroRemo Consortium. ACTA ACUST UNITED AC 2012; 6:73-81. [PMID: 23247145 DOI: 10.1161/circgenetics.112.964965] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Oxidized low-density lipoprotein may be a key factor in the development of atherosclerosis. We performed a genome-wide association study on oxidized low-density lipoprotein and tested the impact of associated single-nucleotide polymorphisms (SNPs) on the risk factors of atherosclerosis and cardiovascular events. METHODS AND RESULTS A discovery genome-wide association study was performed on a population of young healthy white individuals (N=2080), and the SNPs associated with a P<5×10(-8) were replicated in 2 independent samples (A: N=2912; B: N=1326). Associations with cardiovascular endpoints were also assessed with 2 additional clinical cohorts (C: N=1118; and D: N=808). We found 328 SNPs associated with oxidized low-density lipoprotein. The genetic variant rs676210 (Pro2739Leu) in apolipoprotein B was the proxy SNP behind all associations (P=4.3×10(-136), effect size=13.2 U/L per allele). This association was replicated in the 2 independent samples (A and B, P=2.5×10(-47) and 1.1×10(-11), effect sizes=10.3 U/L and 7.8 U/L, respectively). In the meta-analyses of cohorts A, C, and D (excluding cohort B without angiographic data), the top SNP did not associate significantly with the age of onset of angiographically verified coronary artery disease (hazard ratio=1.00 [0.94-1.06] per allele), 3-vessel coronary artery disease (hazard ratio=1.03 [0.94-1.13]), or myocardial infarction (hazard ratio=1.04 [0.96-1.12]). CONCLUSIONS This novel genetic marker is an important factor regulating oxidized low-density lipoprotein levels but not a major genetic factor for the studied cardiovascular endpoints.
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Affiliation(s)
- Kari-Matti Mäkelä
- Department of Clinical Chemistry, Finn-Medi 2, PO Box 2000, FI-33521 Tampere, Finland.
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Lu M, Gantz DL, Herscovitz H, Gursky O. Kinetic analysis of thermal stability of human low density lipoproteins: a model for LDL fusion in atherogenesis. J Lipid Res 2012; 53:2175-2185. [PMID: 22855737 DOI: 10.1194/jlr.m029629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fusion of modified LDL in the arterial wall promotes atherogenesis. Earlier we showed that thermal denaturation mimics LDL remodeling and fusion, and revealed kinetic origin of LDL stability. Here we report the first quantitative analysis of LDL thermal stability. Turbidity data show sigmoidal kinetics of LDL heat denaturation, which is unique among lipoproteins, suggesting that fusion is preceded by other structural changes. High activation energy of denaturation, E(a) = 100 ± 8 kcal/mol, indicates disruption of extensive packing interactions in LDL. Size-exclusion chromatography, nondenaturing gel electrophoresis, and negative-stain electron microscopy suggest that LDL dimerization is an early step in thermally induced fusion. Monoclonal antibody binding suggests possible involvement of apoB N-terminal domain in early stages of LDL fusion. LDL fusion accelerates at pH < 7, which may contribute to LDL retention in acidic atherosclerotic lesions. Fusion also accelerates upon increasing LDL concentration in near-physiologic range, which likely contributes to atherogenesis. Thermal stability of LDL decreases with increasing particle size, indicating that the pro-atherogenic properties of small dense LDL do not result from their enhanced fusion. Our work provides the first kinetic approach to measuring LDL stability and suggests that lipid-lowering therapies that reduce LDL concentration but increase the particle size may have opposite effects on LDL fusion.
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Affiliation(s)
- Mengxiao Lu
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118.
| | - Donald L Gantz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Haya Herscovitz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Olga Gursky
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118.
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