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Schuchardt JP, Kräter M, Schlögel M, Guck J, van Oirschot-Hermans BA, Bos J, van Wijk R, Tintle NL, Westra J, Kerlikowsky F, Hahn A, Harris WS. Omega-3 supplementation changes the physical properties of leukocytes but not erythrocytes in healthy individuals: An exploratory trial. Prostaglandins Leukot Essent Fatty Acids 2024; 202:102636. [PMID: 39159530 DOI: 10.1016/j.plefa.2024.102636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 08/02/2024] [Accepted: 08/06/2024] [Indexed: 08/21/2024]
Abstract
n3-PUFA impact health in several ways, including cardiovascular protection and anti-inflammatory effects, but the underlying mechanisms are not fully understood. In this exploratory study involving 31 healthy subjects, we aimed to investigate the effects of 12 weeks of fish-oil supplementation (1500 mg EPA+DHA/day) on the physical properties of multiple blood cell types. We used deformability cytometry (DC) for all cell types and Laser-assisted Optical Rotational Red Cell Analysis (Lorrca) to assess red blood cell (RBC) deformability. We also investigated the correlation between changes in the physical properties of blood cells and changes in the Omega-3 Index (O3I), defined as the relative content of EPA+DHA in RBCs. Following supplementation, the mean±SD O3I increased from 5.3 %±1.5 % to 8.3 %±1.4 % (p < 0.001). No significant changes in RBC properties were found by both techniques. However, by DC we observed a consistent pattern of physical changes in lymphocytes, neutrophils and monocytes. Among these were significant increases in metrics correlated with the cells' deformability resulting in less stiff cells. The results suggest that leukocytes become softer and have an increased ability to deform under induced short-term physical stress such as hydrodynamic force in the circulation. These changes could impact immune function since softer leukocytes can potentially circulate more easily and could facilitate a more rapid response to systemic inflammation or infection. In conclusion, fish-oil supplementation modulates some physical properties of leukocyte-subfractions, potentially enhancing their biological function. Further studies are warranted to explore the impact of n3-PUFA on blood cell biology, particularly in disease states associated with leukocyte dysregulation.
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Affiliation(s)
- Jan Philipp Schuchardt
- Institute of Food and One Health, Leibniz University Hannover, Hannover, Germany; The Fatty Acid Research Institute, Sioux Falls, SD, USA.
| | - Martin Kräter
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Maximilian Schlögel
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany
| | - Jochen Guck
- Max Planck Institute for the Science of Light & Max-Planck-Zentrum für Physik und Medizin, Erlangen, Germany; Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Brigitte A van Oirschot-Hermans
- Central Diagnostic Laboratory - Red Blood Cell Research Group, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Jennifer Bos
- Central Diagnostic Laboratory - Red Blood Cell Research Group, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Richard van Wijk
- Central Diagnostic Laboratory - Red Blood Cell Research Group, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Nathan L Tintle
- The Fatty Acid Research Institute, Sioux Falls, SD, USA; Department of Population Health Nursing Science, College of Nursing, University of Illinois - Chicago, Chicago, IL, USA
| | - Jason Westra
- The Fatty Acid Research Institute, Sioux Falls, SD, USA
| | - Felix Kerlikowsky
- Institute of Food and One Health, Leibniz University Hannover, Hannover, Germany
| | - Andreas Hahn
- Institute of Food and One Health, Leibniz University Hannover, Hannover, Germany
| | - William S Harris
- The Fatty Acid Research Institute, Sioux Falls, SD, USA; Department of Internal Medicine, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
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2
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Pfister S, Lesieur J, Bourdoncle P, Elhassan M, Didier P, Anton N, Anton H, Collot M. Red-Emitting Pyrrolyl Squaraine Molecular Rotor Reports Variations of Plasma Membrane and Vesicular Viscosity in Fluorescence Lifetime Imaging. Anal Chem 2024; 96:12784-12793. [PMID: 39066698 DOI: 10.1021/acs.analchem.4c02145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
The viscosity that ensures the controlled diffusion of biomolecules in cells is a crucial biophysical parameter. Consequently, fluorescent probes capable of reporting viscosity variations are valuable tools in bioimaging. In this field, red-shifted probes are essential, as the widely used and gold standard probe remains green-emitting molecular rotors based on BODIPY. Here, we demonstrate that pyrrolyl squaraines, red-emissive fluorophores, exhibit high sensitivity over a wide viscosity range from 30 to 4890 mPa·s. Upon alkylation of the pyrrole moieties, the probes improve their sensitivity to viscosity through an enhanced twisted intramolecular charge transfer phenomenon. We utilized this scaffold to develop a plasma membrane probe, pSQ-PM, that efficiently stains the plasma membrane in a fluorogenic manner. Using fluorescence lifetime imaging, pSQ-PM enabled efficient sensing of viscosity variations in the plasma membrane under various conditions and in different cell lines (HeLa, U2OS, and NIH/3T3). Moreover, upon incubation, pSQ-PM stained the membrane of intracellular vesicles and suggested that the lysosomal membranes displayed enhanced fluidity.
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Affiliation(s)
- Sonia Pfister
- Chemistry of Photoresponsive Systems, Laboratoire de Chémo-Biologie Synthétique et Thérapeutique (CBST) UMR 7199, CNRS, Université de Strasbourg, F-67400 Illkirch, France
| | - Julie Lesieur
- Université Paris Cité, CNRS, Inserm, Institut Cochin, F-75014 Paris, France
| | - Pierre Bourdoncle
- Université Paris Cité, CNRS, Inserm, Institut Cochin, F-75014 Paris, France
| | - Mohamed Elhassan
- Université de Strasbourg, INSERM, Regenerative Nanomedicine UMR 1260, Centre de Recherche en Biomédecine de Strasbourg (CRBS), F-67000 Strasbourg, France
- Department of Pharmaceutics, Faculty of Pharmacy, University of Gezira, Wad Medani 21111, Sudan
| | - Pascal Didier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, CNRS, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, Graffenstaden, France
| | - Nicolas Anton
- Université de Strasbourg, INSERM, Regenerative Nanomedicine UMR 1260, Centre de Recherche en Biomédecine de Strasbourg (CRBS), F-67000 Strasbourg, France
| | - Halina Anton
- Laboratoire de Bioimagerie et Pathologies, UMR 7021, CNRS, Université de Strasbourg, 74 route du Rhin, 67401 Illkirch, Graffenstaden, France
| | - Mayeul Collot
- Chemistry of Photoresponsive Systems, Laboratoire de Chémo-Biologie Synthétique et Thérapeutique (CBST) UMR 7199, CNRS, Université de Strasbourg, F-67400 Illkirch, France
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3
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Ashrafuzzaman M, Koeppe RE, Andersen OS. Intrinsic Lipid Curvature and Bilayer Elasticity as Regulators of Channel Function: A Comparative Single-Molecule Study. Int J Mol Sci 2024; 25:2758. [PMID: 38474005 PMCID: PMC10931550 DOI: 10.3390/ijms25052758] [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: 01/06/2024] [Revised: 02/13/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Perturbations in bilayer material properties (thickness, lipid intrinsic curvature and elastic moduli) modulate the free energy difference between different membrane protein conformations, thereby leading to changes in the conformational preferences of bilayer-spanning proteins. To further explore the relative importance of curvature and elasticity in determining the changes in bilayer properties that underlie the modulation of channel function, we investigated how the micelle-forming amphiphiles Triton X-100, reduced Triton X-100 and the HII lipid phase promoter capsaicin modulate the function of alamethicin and gramicidin channels. Whether the amphiphile-induced changes in intrinsic curvature were negative or positive, amphiphile addition increased gramicidin channel appearance rates and lifetimes and stabilized the higher conductance states in alamethicin channels. When the intrinsic curvature was modulated by altering phospholipid head group interactions, however, maneuvers that promote a negative-going curvature stabilized the higher conductance states in alamethicin channels but destabilized gramicidin channels. Using gramicidin channels of different lengths to probe for changes in bilayer elasticity, we found that amphiphile adsorption increases bilayer elasticity, whereas altering head group interactions does not. We draw the following conclusions: first, confirming previous studies, both alamethicin and gramicidin channels are modulated by changes in lipid bilayer material properties, the changes occurring in parallel yet differing dependent on the property that is being changed; second, isolated, negative-going changes in curvature stabilize the higher current levels in alamethicin channels and destabilize gramicidin channels; third, increases in bilayer elasticity stabilize the higher current levels in alamethicin channels and stabilize gramicidin channels; and fourth, the energetic consequences of changes in elasticity tend to dominate over changes in curvature.
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Affiliation(s)
- Mohammad Ashrafuzzaman
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA;
| | - Roger E. Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA;
| | - Olaf S. Andersen
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA;
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4
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Sherratt SCR, Mason RP, Libby P, Steg PG, Bhatt DL. Do patients benefit from omega-3 fatty acids? Cardiovasc Res 2024; 119:2884-2901. [PMID: 38252923 PMCID: PMC10874279 DOI: 10.1093/cvr/cvad188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/11/2023] [Accepted: 09/26/2023] [Indexed: 01/24/2024] Open
Abstract
Omega-3 fatty acids (O3FAs) possess beneficial properties for cardiovascular (CV) health and elevated O3FA levels are associated with lower incident risk for CV disease (CVD.) Yet, treatment of at-risk patients with various O3FA formulations has produced disparate results in large, well-controlled and well-conducted clinical trials. Prescription formulations and fish oil supplements containing low-dose mixtures of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have routinely failed to prevent CV events in primary and secondary prevention settings when added to contemporary care, as shown most recently in the STRENGTH and OMEMI trials. However, as observed in JELIS, REDUCE-IT, and RESPECT-EPA, EPA-only formulations significantly reduce CVD events in high-risk patients. The CV mechanism of action of EPA, while certainly multifaceted, does not depend solely on reductions of circulating lipids, including triglycerides (TG) and LDL, and event reduction appears related to achieved EPA levels suggesting that the particular chemical and biological properties of EPA, as compared to DHA and other O3FAs, may contribute to its distinct clinical efficacy. In vitro and in vivo studies have shown different effects of EPA compared with DHA alone or EPA/DHA combination treatments, on atherosclerotic plaque morphology, LDL and membrane oxidation, cholesterol distribution, membrane lipid dynamics, glucose homeostasis, endothelial function, and downstream lipid metabolite function. These findings indicate that prescription-grade, EPA-only formulations provide greater benefit than other O3FAs formulations tested. This review summarizes the clinical findings associated with various O3FA formulations, their efficacy in treating CV disease, and their underlying mechanisms of action.
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Affiliation(s)
- Samuel C R Sherratt
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
- Elucida Research LLC, Beverly, MA, USA
| | - R Preston Mason
- Elucida Research LLC, Beverly, MA, USA
- Department of Medicine, Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Peter Libby
- Department of Medicine, Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Ph Gabriel Steg
- Université Paris-Cité, INSERM_UMR1148/LVTS, FACT (French Alliance for Cardiovascular Trials), Assistance Publique–Hôpitaux de Paris, Hôpital Bichat, Paris, France
| | - Deepak L Bhatt
- Mount Sinai Fuster Heart Hospital, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, NewYork 10029-5674, NY, USA
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5
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Barrantes FJ. Modulation of a rapid neurotransmitter receptor-ion channel by membrane lipids. Front Cell Dev Biol 2024; 11:1328875. [PMID: 38274273 PMCID: PMC10808158 DOI: 10.3389/fcell.2023.1328875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024] Open
Abstract
Membrane lipids modulate the proteins embedded in the bilayer matrix by two non-exclusive mechanisms: direct or indirect. The latter comprise those effects mediated by the physicochemical state of the membrane bilayer, whereas direct modulation entails the more specific regulatory effects transduced via recognition sites on the target membrane protein. The nicotinic acetylcholine receptor (nAChR), the paradigm member of the pentameric ligand-gated ion channel (pLGIC) superfamily of rapid neurotransmitter receptors, is modulated by both mechanisms. Reciprocally, the nAChR protein exerts influence on its surrounding interstitial lipids. Folding, conformational equilibria, ligand binding, ion permeation, topography, and diffusion of the nAChR are modulated by membrane lipids. The knowledge gained from biophysical studies of this prototypic membrane protein can be applied to other neurotransmitter receptors and most other integral membrane proteins.
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Affiliation(s)
- Francisco J. Barrantes
- Biomedical Research Institute (BIOMED), Catholic University of Argentina (UCA)–National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
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6
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Valentin-Escalera J, Leclerc M, Calon F. High-Fat Diets in Animal Models of Alzheimer's Disease: How Can Eating Too Much Fat Increase Alzheimer's Disease Risk? J Alzheimers Dis 2024; 97:977-1005. [PMID: 38217592 PMCID: PMC10836579 DOI: 10.3233/jad-230118] [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] [Accepted: 11/15/2023] [Indexed: 01/15/2024]
Abstract
High dietary intake of saturated fatty acids is a suspected risk factor for neurodegenerative diseases, including Alzheimer's disease (AD). To decipher the causal link behind these associations, high-fat diets (HFD) have been repeatedly investigated in animal models. Preclinical studies allow full control over dietary composition, avoiding ethical concerns in clinical trials. The goal of the present article is to provide a narrative review of reports on HFD in animal models of AD. Eligibility criteria included mouse models of AD fed a HFD defined as > 35% of fat/weight and western diets containing > 1% cholesterol or > 15% sugar. MEDLINE and Embase databases were searched from 1946 to August 2022, and 32 preclinical studies were included in the review. HFD-induced obesity and metabolic disturbances such as insulin resistance and glucose intolerance have been replicated in most studies, but with methodological variability. Most studies have found an aggravating effect of HFD on brain Aβ pathology, whereas tau pathology has been much less studied, and results are more equivocal. While most reports show HFD-induced impairment on cognitive behavior, confounding factors may blur their interpretation. In summary, despite conflicting results, exposing rodents to diets highly enriched in saturated fat induces not only metabolic defects, but also cognitive impairment often accompanied by aggravated neuropathological markers, most notably Aβ burden. Although there are important variations between methods, particularly the lack of diet characterization, these studies collectively suggest that excessive intake of saturated fat should be avoided in order to lower the incidence of AD.
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Affiliation(s)
- Josue Valentin-Escalera
- Faculté de Pharmacie, Université Laval, Québec, Canada
- Axe Neurosciences, Centre de recherche du centre Hospitalier de l'Université Laval (CHUL), Québec, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels, Québec, Canada
- OptiNutriBrain - Laboratoire International Associé (NutriNeuro France-INAF Canada)
| | - Manon Leclerc
- Faculté de Pharmacie, Université Laval, Québec, Canada
- Axe Neurosciences, Centre de recherche du centre Hospitalier de l'Université Laval (CHUL), Québec, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels, Québec, Canada
- OptiNutriBrain - Laboratoire International Associé (NutriNeuro France-INAF Canada)
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval, Québec, Canada
- Axe Neurosciences, Centre de recherche du centre Hospitalier de l'Université Laval (CHUL), Québec, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels, Québec, Canada
- OptiNutriBrain - Laboratoire International Associé (NutriNeuro France-INAF Canada)
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7
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Jobin ML, De Smedt-Peyrusse V, Ducrocq F, Baccouch R, Oummadi A, Pedersen MH, Medel-Lacruz B, Angelo MF, Villette S, Van Delft P, Fouillen L, Mongrand S, Selent J, Tolentino-Cortez T, Barreda-Gómez G, Grégoire S, Masson E, Durroux T, Javitch JA, Guixà-González R, Alves ID, Trifilieff P. Impact of membrane lipid polyunsaturation on dopamine D2 receptor ligand binding and signaling. Mol Psychiatry 2023; 28:1960-1969. [PMID: 36604603 DOI: 10.1038/s41380-022-01928-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 12/05/2022] [Accepted: 12/14/2022] [Indexed: 01/07/2023]
Abstract
Increasing evidence supports a relationship between lipid metabolism and mental health. In particular, the biostatus of polyunsaturated fatty acids (PUFAs) correlates with some symptoms of psychiatric disorders, as well as the efficacy of pharmacological treatments. Recent findings highlight a direct association between brain PUFA levels and dopamine transmission, a major neuromodulatory system implicated in the etiology of psychiatric symptoms. However, the mechanisms underlying this relationship are still unknown. Here we demonstrate that membrane enrichment in the n-3 PUFA docosahexaenoic acid (DHA), potentiates ligand binding to the dopamine D2 receptor (D2R), suggesting that DHA acts as an allosteric modulator of this receptor. Molecular dynamics simulations confirm that DHA has a high preference for interaction with the D2R and show that membrane unsaturation selectively enhances the conformational dynamics of the receptor around its second intracellular loop. We find that membrane unsaturation spares G protein activity but potentiates the recruitment of β-arrestin in cells. Furthermore, in vivo n-3 PUFA deficiency blunts the behavioral effects of two D2R ligands, quinpirole and aripiprazole. These results highlight the importance of membrane unsaturation for D2R activity and provide a putative mechanism for the ability of PUFAs to enhance antipsychotic efficacy.
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Affiliation(s)
- Marie-Lise Jobin
- Université de Bordeaux, INRAE, Bordeaux INP, NutriNeuro, 33000, Bordeaux, France
| | | | - Fabien Ducrocq
- Université de Bordeaux, INRAE, Bordeaux INP, NutriNeuro, 33000, Bordeaux, France
| | - Rim Baccouch
- Institute of Chemistry & Biology of Membranes & Nanoobjects, CNRS UMR 5248, Université de Bordeaux, Bordeaux INP, 33600, Pessac, France
| | - Asma Oummadi
- Université de Bordeaux, INRAE, Bordeaux INP, NutriNeuro, 33000, Bordeaux, France
| | - Maria Hauge Pedersen
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
| | - Brian Medel-Lacruz
- Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM)-Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), 08003, Barcelona, Spain
| | | | - Sandrine Villette
- Institute of Chemistry & Biology of Membranes & Nanoobjects, CNRS UMR 5248, Université de Bordeaux, Bordeaux INP, 33600, Pessac, France
| | - Pierre Van Delft
- Laboratory of Membrane Biogenesis (LBM), Research Mix Unity (UMR) 5200, National Scientific Research Center (CNRS), University of Bordeaux, Bordeaux, France
| | - Laetitia Fouillen
- Laboratory of Membrane Biogenesis (LBM), Research Mix Unity (UMR) 5200, National Scientific Research Center (CNRS), University of Bordeaux, Bordeaux, France
| | - Sébastien Mongrand
- Laboratory of Membrane Biogenesis (LBM), Research Mix Unity (UMR) 5200, National Scientific Research Center (CNRS), University of Bordeaux, Bordeaux, France
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Medical Research Institute (IMIM)-Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), 08003, Barcelona, Spain
| | | | - Gabriel Barreda-Gómez
- Research Department, IMG Pharma Biotech S.L., BIC Bizkaia (612), 48160, Derio, Spain
| | - Stéphane Grégoire
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, 21000, Dijon, France
| | - Elodie Masson
- Centre des Sciences du Goût et de l'Alimentation, AgroSup Dijon, CNRS, INRAE, Université Bourgogne Franche-Comté, 21000, Dijon, France
| | - Thierry Durroux
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Jonathan A Javitch
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
- Department of Molecular Pharmacology and Therapeutics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - Ramon Guixà-González
- Condensed Matter Theory Group, Paul Scherrer Institute (PSI), 5232, Villigen, PSI, Switzerland.
| | - Isabel D Alves
- Institute of Chemistry & Biology of Membranes & Nanoobjects, CNRS UMR 5248, Université de Bordeaux, Bordeaux INP, 33600, Pessac, France.
| | - Pierre Trifilieff
- Université de Bordeaux, INRAE, Bordeaux INP, NutriNeuro, 33000, Bordeaux, France.
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8
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Peyear TA, Andersen OS. Screening for bilayer-active and likely cytotoxic molecules reveals bilayer-mediated regulation of cell function. J Gen Physiol 2023; 155:e202213247. [PMID: 36763053 PMCID: PMC9948646 DOI: 10.1085/jgp.202213247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 12/06/2022] [Accepted: 01/13/2023] [Indexed: 02/11/2023] Open
Abstract
A perennial problem encountered when using small molecules (drugs) to manipulate cell or protein function is to assess whether observed changes in function result from specific interactions with a desired target or from less specific off-target mechanisms. This is important in laboratory research as well as in drug development, where the goal is to identify molecules that are unlikely to be successful therapeutics early in the process, thereby avoiding costly mistakes. We pursued this challenge from the perspective that many bioactive molecules (drugs) are amphiphiles that alter lipid bilayer elastic properties, which may cause indiscriminate changes in membrane protein (and cell) function and, in turn, cytotoxicity. Such drug-induced changes in bilayer properties can be quantified as changes in the monomer↔dimer equilibrium for bilayer-spanning gramicidin channels. Using this approach, we tested whether molecules in the Pathogen Box (a library of 400 drugs and drug-like molecules with confirmed activity against tropical diseases released by Medicines for Malaria Venture to encourage the development of therapies for neglected tropical diseases) are bilayer modifiers. 32% of the molecules in the Pathogen Box were bilayer modifiers, defined as molecules that at 10 µM shifted the monomer↔dimer equilibrium toward the conducting dimers by at least 50%. Correlation analysis of the molecules' reported HepG2 cell cytotoxicity to bilayer-modifying potency, quantified as the shift in the gramicidin monomer↔dimer equilibrium, revealed that molecules producing <25% change in the equilibrium had significantly lower probability of being cytotoxic than molecules producing >50% change. Neither cytotoxicity nor bilayer-modifying potency (quantified as the shift in the gramicidin monomer↔dimer equilibrium) was well predicted by conventional physico-chemical descriptors (hydrophobicity, polar surface area, etc.). We conclude that drug-induced changes in lipid bilayer properties are robust predictors of the likelihood of membrane-mediated off-target effects, including cytotoxicity.
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Affiliation(s)
- Thasin A. Peyear
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
- Graduate Program in Physiology, Biophysics and Systems Biology, Weill Cornell Graduate School of Medical Sciences. New York, NY, USA
| | - Olaf S. Andersen
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
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9
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Ugwuodo CJ, Colosimo F, Adhikari J, Shen Y, Badireddy AR, Mouser PJ. Salinity and hydraulic retention time induce membrane phospholipid acyl chain remodeling in Halanaerobium congolense WG10 and mixed cultures from hydraulically fractured shale wells. Front Microbiol 2022; 13:1023575. [PMID: 36439785 PMCID: PMC9687094 DOI: 10.3389/fmicb.2022.1023575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2023] Open
Abstract
Bacteria remodel their plasma membrane lipidome to maintain key biophysical attributes in response to ecological disturbances. For Halanaerobium and other anaerobic halotolerant taxa that persist in hydraulically fractured deep subsurface shale reservoirs, salinity, and hydraulic retention time (HRT) are important perturbants of cell membrane structure, yet their effects remain poorly understood. Membrane-linked activities underlie in situ microbial growth kinetics and physiologies which drive biogeochemical reactions in engineered subsurface systems. Hence, we used gas chromatography-mass spectrometry (GC-MS) to investigate the effects of salinity and HRT on the phospholipid fatty acid composition of H. congolense WG10 and mixed enrichment cultures from hydraulically fractured shale wells. We also coupled acyl chain remodeling to membrane mechanics by measuring bilayer elasticity using atomic force microscopy (AFM). For these experiments, cultures were grown in a chemostat vessel operated in continuous flow mode under strict anoxia and constant stirring. Our findings show that salinity and HRT induce significant changes in membrane fatty acid chemistry of H. congolense WG10 in distinct and complementary ways. Notably, under nonoptimal salt concentrations (7% and 20% NaCl), H. congolense WG10 elevates the portion of polyunsaturated fatty acids (PUFAs) in its membrane, and this results in an apparent increase in fluidity (homeoviscous adaptation principle) and thickness. Double bond index (DBI) and mean chain length (MCL) were used as proxies for membrane fluidity and thickness, respectively. These results provide new insight into our understanding of how environmental and engineered factors might disrupt the physical and biogeochemical equilibria of fractured shale by inducing physiologically relevant changes in the membrane fatty acid chemistry of persistent microbial taxa. GRAPHICAL ABSTRACTSalinity significantly alters membrane bilayer fluidity and thickness in Halanaerobium congolense WG10.
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Affiliation(s)
- Chika Jude Ugwuodo
- Natural Resources and Earth Systems Science, University of New Hampshire, Durham, NH, United States
- Department of Civil and Environmental Engineering, University of New Hampshire, Durham, NH, United States
| | | | - Jishnu Adhikari
- Sanborn, Head and Associates, Inc., Concord, NH, United States
| | - Yuxiang Shen
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States
| | - Appala Raju Badireddy
- Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT, United States
| | - Paula J. Mouser
- Department of Civil and Environmental Engineering, University of New Hampshire, Durham, NH, United States
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10
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Zhou L, Xiong JY, Chai YQ, Huang L, Tang ZY, Zhang XF, Liu B, Zhang JT. Possible antidepressant mechanisms of omega-3 polyunsaturated fatty acids acting on the central nervous system. Front Psychiatry 2022; 13:933704. [PMID: 36117650 PMCID: PMC9473681 DOI: 10.3389/fpsyt.2022.933704] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Omega-3 polyunsaturated fatty acids (PUFAs) can play important roles in maintaining mental health and resistance to stress, and omega-3 PUFAs supplementation can display beneficial effects on both the prevention and treatment of depressive disorders. Although the underlying mechanisms are still unclear, accumulated evidence indicates that omega-3 PUFAs can exhibit pleiotropic effects on the neural structure and function. Thus, they play fundamental roles in brain activities involved in the mood regulation. Since depressive symptoms have been assumed to be of central origin, this review aims to summarize the recently published studies to identify the potential neurobiological mechanisms underlying the anti-depressant effects of omega-3 PUFAs. These include that of (1) anti-neuroinflammatory; (2) hypothalamus-pituitary-adrenal (HPA) axis; (3) anti-oxidative stress; (4) anti-neurodegeneration; (5) neuroplasticity and synaptic plasticity; and (6) modulation of neurotransmitter systems. Despite many lines of evidence have hinted that these mechanisms may co-exist and work in concert to produce anti-depressive effects, the potentially multiple sites of action of omega-3 PUFAs need to be fully established. We also discussed the limitations of current studies and suggest future directions for preclinical and translational research in this field.
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Affiliation(s)
- Lie Zhou
- Yangtze University Health Science Center, Jingzhou, China
- Mental Health Institute of Yangtze University, Jingzhou, China
| | - Jia-Yao Xiong
- Yangtze University Health Science Center, Jingzhou, China
| | - Yu-Qian Chai
- Yangtze University Health Science Center, Jingzhou, China
| | - Lu Huang
- Yangtze University Health Science Center, Jingzhou, China
- Mental Health Institute of Yangtze University, Jingzhou, China
| | - Zi-Yang Tang
- Yangtze University Health Science Center, Jingzhou, China
- Mental Health Institute of Yangtze University, Jingzhou, China
- Jingzhou Mental Health Center, Jingzhou, China
| | - Xin-Feng Zhang
- Mental Health Institute of Yangtze University, Jingzhou, China
- Jingzhou Mental Health Center, Jingzhou, China
| | - Bo Liu
- Mental Health Institute of Yangtze University, Jingzhou, China
- Jingzhou Mental Health Center, Jingzhou, China
| | - Jun-Tao Zhang
- Yangtze University Health Science Center, Jingzhou, China
- Mental Health Institute of Yangtze University, Jingzhou, China
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11
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Cheng V, Rallabandi R, Gorusupudi A, Lucas S, Rognon G, Bernstein PS, Rainier JD, Conboy JC. Influence of very-long-chain polyunsaturated fatty acids on membrane structure and dynamics. Biophys J 2022; 121:2730-2741. [PMID: 35711144 DOI: 10.1016/j.bpj.2022.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/24/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022] Open
Abstract
The unique attributes of very-long-chain polyunsaturated fatty acids (VLC-PUFAs), their long carbon chains (n > 24) and high degree of unsaturation, impart unique chemical and physical properties to this class of fatty acids. The changes imparted by VLC-PUFA 32:6 n-3 on lipid packing and the compression moduli of model membranes were evaluated from π-A isotherms of VLC-PUFA in 1,2-distearoyl-sn-3-glycero-phosphocholine (DSPC) lipid monolayers. To compare the attractive or repulsive forces between VLC-PUFA and DSPC lipid monolayers, the measured mean molecular areas (MMAs) were compared with the calculated MMAs of an ideal mixture of VLC-PUFA and DSPC. The presence of 0.1, 1, and 10 mol % VLC-PUFA shifted the π-A isotherm to higher MMAs of the lipids comprising the membrane and the observed positive deviations from ideal behavior of the mixed VLC-PUFA:DSPC monolayers correspond to repulsive forces between VLC-PUFAs and DSPC. The MMA of the VLC-PUFA component was estimated using the measured MMAs of DSPC of 47.1 ± 0.7 Å2/molecule, to be 15,000, 1100, and 91 Å2/molecule at 0.1, 1, and 10 mol % VLC-PUFA:DSPC mixtures, respectively. The large MMAs of VLC-PUFA suggest that the docosahexaenoic acid tail reinserts into the membrane and adopts a nonlinear structure in the membrane, which is most pronounced at 0.1 mol % VLC-PUFA. The presence of 0.1 mol % VLC-PUFA:DSPC also significantly increased the compression modulus of the membrane by 28 mN/m compared with a pure DSPC membrane. The influence of VLC-PUFA on lipid "flip-flop" was investigated by sum-frequency vibrational spectroscopy. The incorporation of 0.1 mol % VLC-PUFA increased the DSPC flip-flop rate fourfold. The fact that VLC-PUFA promotes lipid translocation is noteworthy as retinal membranes require a high influx of retinoids which may be facilitated by lipid flip-flop.
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Affiliation(s)
- Victoria Cheng
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | | | - Aruna Gorusupudi
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Steven Lucas
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - Gregory Rognon
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Paul S Bernstein
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Jon D Rainier
- Department of Chemistry, University of Utah, Salt Lake City, Utah
| | - John C Conboy
- Department of Chemistry, University of Utah, Salt Lake City, Utah.
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12
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Li J, Mao M, Li J, Chen Z, Ji Y, Kong J, Wang Z, Zhang J, Wang Y, Liang W, Liang H, Lv L, Liu Q, Yan R, Yuan H, Chen K, Chang Y, Chen G, Xing G. Oral Administration of Omega-3 Fatty Acids Attenuates Lung Injury Caused by PM2.5 Respiratory Inhalation Simply and Feasibly In Vivo. Int J Mol Sci 2022; 23:ijms23105323. [PMID: 35628131 PMCID: PMC9140442 DOI: 10.3390/ijms23105323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/02/2022] [Accepted: 05/06/2022] [Indexed: 02/07/2023] Open
Abstract
For developing an effective interventional approach and treatment modality for PM2.5, the effects of omega-3 fatty acids on alleviating inflammation and attenuating lung injury induced by inhalation exposure of PM2.5 were assessed in murine models. We found that daily oral administration of the active components of omega-3 fatty acids, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) effectively alleviated lung parenchymal lesions, restored normal inflammatory cytokine levels and oxidative stress levels in treating mice exposed to PM2.5 (20 mg/kg) every 3 days for 5 times over a 14-day period. Especially, CT images and the pathological analysis suggested protective effects of DHA and EPA on lung injury. The key molecular mechanism is that DHA and EPA can inhibit the entry and deposition of PM2.5, and block the PM2.5-mediated cytotoxicity, oxidative stress, and inflammation.
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Affiliation(s)
- Juan Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
- Correspondence: (J.L.); (G.X.)
| | - Meiru Mao
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Jiacheng Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Ziteng Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Ying Ji
- Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong;
| | - Jianglong Kong
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Zhijie Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Jiaxin Zhang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Yujiao Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Wei Liang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Haojun Liang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Linwen Lv
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Qiuyang Liu
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Ruyu Yan
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Hui Yuan
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Kui Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Yanan Chang
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
| | - Guogang Chen
- College of Food Science, Shihezi University, Shihezi 832000, China;
| | - Gengmei Xing
- CAS Key Laboratory for Biomedical Effects of Nanomaterial & Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China; (M.M.); (J.L.); (Z.C.); (J.K.); (Z.W.); (J.Z.); (Y.W.); (W.L.); (H.L.); (L.L.); (Q.L.); (R.Y.); (H.Y.); (K.C.); (Y.C.)
- Correspondence: (J.L.); (G.X.)
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13
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Maer AM, Rusinova R, Providence LL, Ingólfsson HI, Collingwood SA, Lundbæk JA, Andersen OS. Regulation of Gramicidin Channel Function Solely by Changes in Lipid Intrinsic Curvature. Front Physiol 2022; 13:836789. [PMID: 35350699 PMCID: PMC8957996 DOI: 10.3389/fphys.2022.836789] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
Membrane protein function is regulated by the lipid bilayer composition. In many cases the changes in function correlate with changes in the lipid intrinsic curvature (c 0), and c 0 is considered a determinant of protein function. Yet, water-soluble amphiphiles that cause either negative or positive changes in curvature have similar effects on membrane protein function, showing that changes in lipid bilayer properties other than c 0 are important-and may be dominant. To further investigate the mechanisms underlying the bilayer regulation of protein function, we examined how maneuvers that alter phospholipid head groups effective "size"-and thereby c 0-alter gramicidin (gA) channel function. Using dioleoylphospholipids and planar bilayers, we varied the head groups' physical volume and the electrostatic repulsion among head groups (and thus their effective size). When 1,2-dioleyol-sn-glycero-3-phosphocholine (DOPC), was replaced by 1,2-dioleyol-sn-glycero-3-phosphoethanolamine (DOPE) with a smaller head group (causing a more negative c 0), the channel lifetime (τ) is decreased. When the pH of the solution bathing a 1,2-dioleyol-sn-glycero-3-phosphoserine (DOPS) bilayer is decreased from 7 to 3 (causing decreased head group repulsion and a more negative c 0), τ is decreased. When some DOPS head groups are replaced by zwitterionic head groups, τ is similarly decreased. These effects do not depend on the sign of the change in surface charge. In DOPE:DOPC (3:1) bilayers, pH changes from 5→9 to 5→0 (both increasing head group electrostatic repulsion, thereby causing a less negative c 0) both increase τ. Nor do the effects depend on the use of planar, hydrocarbon-containing bilayers, as similar changes were observed in hydrocarbon-free lipid vesicles. Altering the interactions among phospholipid head groups may alter also other bilayer properties such as thickness or elastic moduli. Such changes could be excluded using capacitance measurements and single channel measurements on gA channels of different lengths. We conclude that changes gA channel function caused by changes in head group effective size can be predicted from the expected changes in c 0.
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Affiliation(s)
| | | | | | | | | | | | - Olaf S. Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States
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14
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Kondrashov OV, Akimov SA. Regulation of Antimicrobial Peptide Activity via Tuning Deformation Fields by Membrane-Deforming Inclusions. Int J Mol Sci 2021; 23:ijms23010326. [PMID: 35008752 PMCID: PMC8745196 DOI: 10.3390/ijms23010326] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/22/2021] [Accepted: 12/28/2021] [Indexed: 01/10/2023] Open
Abstract
Antimicrobial peptides (AMPs) are considered prospective antibiotics. Some AMPs fight bacteria via cooperative formation of pores in their plasma membranes. Most AMPs at their working concentrations can induce lysis of eukaryotic cells as well. Gramicidin A (gA) is a peptide, the transmembrane dimers of which form cation-selective channels in membranes. It is highly toxic for mammalians as being majorly hydrophobic gA incorporates and induces leakage of both bacterial and eukaryotic cell membranes. Both pore-forming AMPs and gA deform the membrane. Here we suggest a possible way to reduce the working concentrations of AMPs at the expense of application of highly-selective amplifiers of AMP activity in target membranes. The amplifiers should alter the deformation fields in the membrane in a way favoring the membrane-permeabilizing states. We developed the statistical model that allows describing the effect of membrane-deforming inclusions on the equilibrium between AMP monomers and cooperative membrane-permeabilizing structures. On the example of gA monomer-dimer equilibrium, the model predicts that amphipathic peptides and short transmembrane peptides playing the role of the membrane-deforming inclusions, even in low concentration can substantially increase the lifetime and average number of gA channels.
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15
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Lin YF. Potassium channels as molecular targets of endocannabinoids. Channels (Austin) 2021; 15:408-423. [PMID: 34282702 PMCID: PMC8293965 DOI: 10.1080/19336950.2021.1910461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 10/25/2022] Open
Abstract
Endocannabinoids are a group of endogenous mediators derived from membrane lipids, which are implicated in a wide variety of physiological functions such as blood pressure regulation, immunity, pain, memory, reward, perception, reproduction, and sleep. N-Arachidonoylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG) represent two major endocannabinoids in the human body and they exert many of their cellular and organ system effects by activating the Gi/o protein-coupled, cannabinoid type 1 (CB1) and type 2 (CB2) receptors. However, not all effects of cannabinoids are ascribable to their interaction with CB1 and CB2 receptors; indeed, macromolecules like other types of receptors, ion channels, transcription factors, enzymes, transporters, and cellular structure have been suggested to mediate the functional effects of cannabinoids. Among the proposed molecular targets of endocannabinoids, potassium channels constitute an intriguing group, because these channels not only are crucial in shaping action potentials and controlling the membrane potential and cell excitability, thereby regulating a wide array of physiological processes, but also serve as potential therapeutic targets for the treatment of cancer and metabolic, neurological and cardiovascular disorders. This review sought to survey evidence pertaining to the CB1 and CB2 receptor-independent actions of endocannabinoids on ion channels, with an emphasis on AEA and potassium channels. To better understand the functional roles as well as potential medicinal uses of cannabinoids in human health and disease, further mechanistic studies to delineate interactions between various types of cannabinoids and ion channels, including members in the potassium channel superfamily, are warranted.
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Affiliation(s)
- Yu-Fung Lin
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
- Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, CA, USA
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16
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Axmann M, Plochberger B, Mikula M, Weber F, Strobl WM, Stangl H. Plasma Membrane Lipids: An Important Binding Site for All Lipoprotein Classes. MEMBRANES 2021; 11:membranes11110882. [PMID: 34832111 PMCID: PMC8622984 DOI: 10.3390/membranes11110882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 12/23/2022]
Abstract
Cholesterol is one of the main constituents of plasma membranes; thus, its supply is of utmost importance. This review covers the known mechanisms of cholesterol transfer from circulating lipoprotein particles to the plasma membrane, and vice versa. To achieve homeostasis, the human body utilizes cellular de novo synthesis and extracellular transport particles for supply of cholesterol and other lipids via the blood stream. These lipoprotein particles can be classified according to their density: chylomicrons, very low, low, and high-density lipoprotein (VLDL, LDL, and HDL, respectively). They deliver and receive their lipid loads, most importantly cholesterol, to and from cells by several redundant routes. Defects in one of these pathways (e.g., due to mutations in receptors) usually are not immediately fatal. Several redundant pathways, at least temporarily, compensate for the loss of one or more of them, but the defects trigger systemic diseases, such as atherosclerosis later on. Recently, intracellular membrane–membrane contact sites were shown to be involved in intracellular cholesterol transfer and the plasma membrane itself has been proposed to act as a binding site for lipoprotein-mediated cargo unloading.
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Affiliation(s)
- Markus Axmann
- School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria; (M.A.); (B.P.); (F.W.)
| | - Birgit Plochberger
- School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria; (M.A.); (B.P.); (F.W.)
| | - Mario Mikula
- Center for Pathobiochemistry and Genetics, Institute for Medical Genetics, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria;
| | - Florian Weber
- School of Medical Engineering and Applied Social Sciences, University of Applied Sciences Upper Austria, Garnisonstrasse 21, 4020 Linz, Austria; (M.A.); (B.P.); (F.W.)
| | - Witta Monika Strobl
- Center for Pathobiochemistry and Genetics, Institute for Medical Chemistry, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria;
| | - Herbert Stangl
- Center for Pathobiochemistry and Genetics, Institute for Medical Chemistry, Medical University of Vienna, Währingerstrasse 10, 1090 Vienna, Austria;
- Correspondence:
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17
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Kalathingal M, Sumikama T, Oiki S, Saito S. Vectorial insertion of a β-helical peptide into membrane: a theoretical study on polytheonamide B. Biophys J 2021; 120:4786-4797. [PMID: 34555359 DOI: 10.1016/j.bpj.2021.09.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 09/07/2021] [Accepted: 09/15/2021] [Indexed: 10/20/2022] Open
Abstract
Spontaneous unidirectional, or vectorial, insertion of transmembrane peptides is a fundamental biophysical process for toxin and viral actions. Polytheonamide B (pTB) is a potent cytotoxic peptide with a β6.3-helical structure. Previous experimental studies revealed that the pTB inserts into the membrane in a vectorial fashion and forms a channel with its single molecular length long enough to span the membrane. Also, molecular dynamics simulation studies demonstrated that the pTB is prefolded in aqueous solution. These are unique features of pTB because most of the peptide toxins form channels through oligomerization of transmembrane helices. Here, we performed all-atom molecular dynamics simulations to examine the dynamic mechanism of the vectorial insertion of pTB, providing underlying elementary processes of the membrane insertion of a prefolded single transmembrane peptide. We find that the insertion of pTB proceeds with only the local lateral compression of the membrane in three successive phases: "landing," "penetration," and "equilibration" phases. The free energy calculations using the replica-exchange umbrella sampling simulations present an energy cost of 4.3 kcal/mol at the membrane surface for the membrane insertion of pTB from bulk water. The trajectories of membrane insertion revealed that the insertion process can occur in two possible pathways, namely "trapped" and "untrapped" insertions; in some cases, pTB is trapped in the upper leaflet during the penetration phase. Our simulations demonstrated the importance of membrane anchoring by the hydrophobic N-terminal blocking group in the landing phase, leading to subsequent vectorial insertion.
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Affiliation(s)
- Mahroof Kalathingal
- School of Physical Sciences, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Takashi Sumikama
- PRESTO, JST, Kawaguchi, Japan; Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
| | - Shigetoshi Oiki
- Biomedical Imaging Research Center, University of Fukui, Fukui, Japan.
| | - Shinji Saito
- School of Physical Sciences, The Graduate University for Advanced Studies, Okazaki, Japan; Institute for Molecular Science, Okazaki, Japan.
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18
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Retinoid X Receptor α Regulates DHA-Dependent Spinogenesis and Functional Synapse Formation In Vivo. Cell Rep 2021; 31:107649. [PMID: 32433958 DOI: 10.1016/j.celrep.2020.107649] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 02/01/2020] [Accepted: 04/22/2020] [Indexed: 12/23/2022] Open
Abstract
Coordinated intracellular and extracellular signaling is critical to synapse development and functional neural circuit wiring. Here, we report that unesterified docosahexaenoic acid (DHA) regulates functional synapse formation in vivo via retinoid X receptor α (Rxra) signaling. Using Rxra conditional knockout (cKO) mice and virus-mediated transient gene expression, we show that endogenous Rxra plays important roles in regulating spinogenesis and excitatory synaptic transmission in cortical pyramidal neurons. We further show that the effects of RXRA are mediated through its DNA-binding domain in a cell-autonomous and reversible manner. Moreover, unesterified DHA increases spine formation and excitatory synaptic transmission in vivo in an Rxra-dependent fashion. Rxra cKO mice generally behave normally but show deficits in behavior tasks associated with social memory. Together, these results demonstrate that unesterified DHA signals through RXRA to regulate spinogenesis and functional synapse formation, providing insight into the mechanism through which DHA promotes brain development and cognitive function.
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19
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EPA and DHA differentially modulate membrane elasticity in the presence of cholesterol. Biophys J 2021; 120:2317-2329. [PMID: 33887229 PMCID: PMC8390804 DOI: 10.1016/j.bpj.2021.04.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/15/2021] [Accepted: 04/09/2021] [Indexed: 12/16/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs) modify the activity of a wide range of membrane proteins and are increasingly hypothesized to modulate protein activity by indirectly altering membrane physical properties. Among the various physical properties affected by PUFAs, the membrane area expansion modulus (Ka), which measures membrane strain in response to applied force, is expected to be a significant controller of channel activity. Yet, the impact of PUFAs on membrane Ka has not been measured previously. Through a series of micropipette aspiration studies, we measured the apparent Ka (Kapp) of phospholipid model membranes containing nonesterified fatty acids. First, we measured membrane Kapp as a function of the location of the unsaturated bonds and degree of unsaturation in the incorporated fatty acids and found that Kapp generally decreases in the presence of fatty acids with three or more unsaturated bonds. Next, we assessed how select ω-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), affect the Kapp of membranes containing cholesterol. In vesicles prepared with high amounts of cholesterol, which should increase the propensity of the membrane to phase segregate, we found that inclusion of DHA decreases the Kapp in comparison to EPA. We also measured how these ω-3 PUFAs affect membrane fluidity and bending rigidity to determine how membrane Kapp changes in relation to these other physical properties. Our study shows that PUFAs generally decrease the Kapp of membranes and that EPA and DHA have differential effects on Kapp when membranes contain higher levels of cholesterol. Our results suggest membrane phase behavior and the distribution of membrane-elasticizing amphiphiles impact the ability of a membrane to stretch.
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20
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Zakany F, Szabo M, Batta G, Kárpáti L, Mándity IM, Fülöp P, Varga Z, Panyi G, Nagy P, Kovacs T. An ω-3, but Not an ω-6 Polyunsaturated Fatty Acid Decreases Membrane Dipole Potential and Stimulates Endo-Lysosomal Escape of Penetratin. Front Cell Dev Biol 2021; 9:647300. [PMID: 33912562 PMCID: PMC8074792 DOI: 10.3389/fcell.2021.647300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 03/22/2021] [Indexed: 12/21/2022] Open
Abstract
Although the largely positive intramembrane dipole potential (DP) may substantially influence the function of transmembrane proteins, its investigation is deeply hampered by the lack of measurement techniques suitable for high-throughput examination of living cells. Here, we describe a novel emission ratiometric flow cytometry method based on F66, a 3-hydroxiflavon derivative, and demonstrate that 6-ketocholestanol, cholesterol and 7-dehydrocholesterol, saturated stearic acid (SA) and ω-6 γ-linolenic acid (GLA) increase, while ω-3 α-linolenic acid (ALA) decreases the DP. These changes do not correlate with alterations in cell viability or membrane fluidity. Pretreatment with ALA counteracts, while SA or GLA enhances cholesterol-induced DP elevations. Furthermore, ALA (but not SA or GLA) increases endo-lysosomal escape of penetratin, a cell-penetrating peptide. In summary, we have developed a novel method to measure DP in large quantities of individual living cells and propose ALA as a physiological DP lowering agent facilitating cytoplasmic entry of penetratin.
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Affiliation(s)
- Florina Zakany
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Mate Szabo
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gyula Batta
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Levente Kárpáti
- Department of Organic Chemistry, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
| | - István M. Mándity
- Department of Organic Chemistry, Faculty of Pharmacy, Semmelweis University, Budapest, Hungary
- Lendület-Artificial Chloride Ion Transporter Group, Institute of Materials and Environmental Chemistry, Research Center for Natural Sciences, Budapest, Hungary
| | - Péter Fülöp
- Division of Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zoltan Varga
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gyorgy Panyi
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Peter Nagy
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamas Kovacs
- Division of Biophysics, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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21
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Martinat M, Rossitto M, Di Miceli M, Layé S. Perinatal Dietary Polyunsaturated Fatty Acids in Brain Development, Role in Neurodevelopmental Disorders. Nutrients 2021; 13:1185. [PMID: 33918517 PMCID: PMC8065891 DOI: 10.3390/nu13041185] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 12/26/2022] Open
Abstract
n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential fatty acids that are provided by dietary intake. Growing evidence suggests that n-3 and n-6 PUFAs are paramount for brain functions. They constitute crucial elements of cellular membranes, especially in the brain. They are the precursors of several metabolites with different effects on inflammation and neuron outgrowth. Overall, long-chain PUFAs accumulate in the offspring brain during the embryonic and post-natal periods. In this review, we discuss how they accumulate in the developing brain, considering the maternal dietary supply, the polymorphisms of genes involved in their metabolism, and the differences linked to gender. We also report the mechanisms linking their bioavailability in the developing brain, their transfer from the mother to the embryo through the placenta, and their role in brain development. In addition, data on the potential role of altered bioavailability of long-chain n-3 PUFAs in the etiologies of neurodevelopmental diseases, such as autism, attention deficit and hyperactivity disorder, and schizophrenia, are reviewed.
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22
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Leclerc M, Dudonné S, Calon F. Can Natural Products Exert Neuroprotection without Crossing the Blood-Brain Barrier? Int J Mol Sci 2021; 22:ijms22073356. [PMID: 33805947 PMCID: PMC8037419 DOI: 10.3390/ijms22073356] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/19/2021] [Accepted: 03/20/2021] [Indexed: 12/17/2022] Open
Abstract
The scope of evidence on the neuroprotective impact of natural products has been greatly extended in recent years. However, a key question that remains to be answered is whether natural products act directly on targets located in the central nervous system (CNS), or whether they act indirectly through other mechanisms in the periphery. While molecules utilized for brain diseases are typically bestowed with a capacity to cross the blood–brain barrier, it has been recently uncovered that peripheral metabolism impacts brain functions, including cognition. The gut–microbiota–brain axis is receiving increasing attention as another indirect pathway for orally administered compounds to act on the CNS. In this review, we will briefly explore these possibilities focusing on two classes of natural products: omega-3 polyunsaturated fatty acids (n-3 PUFAs) from marine sources and polyphenols from plants. The former will be used as an example of a natural product with relatively high brain bioavailability but with tightly regulated transport and metabolism, and the latter as an example of natural compounds with low brain bioavailability, yet with a growing amount of preclinical and clinical evidence of efficacy. In conclusion, it is proposed that bioavailability data should be sought early in the development of natural products to help identifying relevant mechanisms and potential impact on prevalent CNS disorders, such as Alzheimer’s disease.
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Affiliation(s)
- Manon Leclerc
- Faculté de Pharmacie, Université Laval, Québec, QC G1V 0A6, Canada;
- Axe Neurosciences, Centre de Recherche du CHU de Québec–Université Laval, Québec, QC G1V 4G2, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, QC G1V 0A6, Canada;
- OptiNutriBrain-Laboratoire International Associé (NutriNeuro France-INAF Canada), Québec, QC G1V 0A6, Canada
| | - Stéphanie Dudonné
- Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, QC G1V 0A6, Canada;
- OptiNutriBrain-Laboratoire International Associé (NutriNeuro France-INAF Canada), Québec, QC G1V 0A6, Canada
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval, Québec, QC G1V 0A6, Canada;
- Axe Neurosciences, Centre de Recherche du CHU de Québec–Université Laval, Québec, QC G1V 4G2, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Québec, QC G1V 0A6, Canada;
- OptiNutriBrain-Laboratoire International Associé (NutriNeuro France-INAF Canada), Québec, QC G1V 0A6, Canada
- Correspondence: ; Tel.: +1-(418)-525-4444 (ext. 48697); Fax: +1-(418)-654-2761
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23
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Keating CE, Browne KD, Cullen DK. Dietary manipulation of vulnerability to traumatic brain injury-induced neuronal plasma membrane permeability. Exp Neurol 2021; 340:113649. [PMID: 33600812 DOI: 10.1016/j.expneurol.2021.113649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/22/2021] [Accepted: 02/12/2021] [Indexed: 01/22/2023]
Abstract
Traumatic brain injury (TBI) can produce physical disruptions in the plasma membranes of neurons, referred to as mechanoporation, which lead to increased cell permeability. We suspect that such trauma-induced membrane disruptions may be influenced by the physical properties of the plasma membrane, such as elasticity or rigidity. These membrane properties are influenced by lipid composition, which can be modulated via diet, leading to the intriguing possibility of prophylactically altering diet to confer resiliency to this mechanism of acute neuronal damage in TBI. In this proof-of-concept study, we used three different diets-one high in polyunsaturated fatty acids suggested to increase elasticity (Fish Oil), one high in saturated fatty acids and cholesterol suggested to increase rigidity (High Fat), and one standard rat chow (Control)-to alter brain plasma membrane lipid composition before subjecting rats to lateral fluid percussion injury (FPI). Lipid analysis (n = 12 rats) confirmed that diets altered brain fatty acid composition after 4 weeks of feeding, with the Fish Oil diet increasing unsaturated fatty acids, and interestingly, the High Fat diet increasing omega-6 docosapentaenoic acid. One cohort of animals (n = 34 rats) was assessed immediately after FPI or sham injury for acute changes in neuronal membrane permeability in the injury-adjacent cortex. Surprisingly, sham animals fed Fish Oil had increased membrane permeability, suggesting altered passive membrane properties. In contrast, injured animals fed the High Fat diet displayed less intense uptake of permeability marker, suggesting a reduced extent of injury-induced plasma membrane disruption, although the density of affected cells matched the other diet groups. In a separate cohort survived for 7 days after FPI (n = 48 rats), animals fed the High Fat diet exhibited a reduced lesion area. At both time points there were no statistically significant differences in inflammation. Unexpectedly, these results indicate that the High Fat diet, as opposed to the Fish Oil diet, beneficially modulated acute plasma membrane permeability and resulted in a smaller lesion size at 7 days post-injury. Additional studies are necessary to determine the impact of these various diets on behavioral outcomes post-TBI. Further investigation is also needed to understand the physical properties in neuronal plasma membranes that may underlie increased resiliency to trauma-induced disruptions and, importantly, to understand how these properties may be influenced by targeted dietary modifications for vulnerable populations.
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Affiliation(s)
- Carolyn E Keating
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, 19104, USA.
| | - Kevin D Browne
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, 19104, USA.
| | - D Kacy Cullen
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz VA Medical Center, 19104, USA.
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24
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Kozłowski J, Konarzewski M, Czarnoleski M. Coevolution of body size and metabolic rate in vertebrates: a life-history perspective. Biol Rev Camb Philos Soc 2020; 95:1393-1417. [PMID: 32524739 PMCID: PMC7540708 DOI: 10.1111/brv.12615] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 05/05/2020] [Accepted: 05/07/2020] [Indexed: 12/30/2022]
Abstract
Despite many decades of research, the allometric scaling of metabolic rates (MRs) remains poorly understood. Here, we argue that scaling exponents of these allometries do not themselves mirror one universal law of nature but instead statistically approximate the non-linearity of the relationship between MR and body mass. This 'statistical' view must be replaced with the life-history perspective that 'allows' organisms to evolve myriad different life strategies with distinct physiological features. We posit that the hypoallometric allometry of MRs (mass scaling with an exponent smaller than 1) is an indirect outcome of the selective pressure of ecological mortality on allocation 'decisions' that divide resources among growth, reproduction, and the basic metabolic costs of repair and maintenance reflected in the standard or basal metabolic rate (SMR or BMR), which are customarily subjected to allometric analyses. Those 'decisions' form a wealth of life-history variation that can be defined based on the axis dictated by ecological mortality and the axis governed by the efficiency of energy use. We link this variation as well as hypoallometric scaling to the mechanistic determinants of MR, such as metabolically inert component proportions, internal organ relative size and activity, cell size and cell membrane composition, and muscle contributions to dramatic metabolic shifts between the resting and active states. The multitude of mechanisms determining MR leads us to conclude that the quest for a single-cause explanation of the mass scaling of MRs is futile. We argue that an explanation based on the theory of life-history evolution is the best way forward.
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Affiliation(s)
- Jan Kozłowski
- Institute of Environmental SciencesJagiellonian UniversityGronostajowa7, 30‐387KrakówPoland
| | - Marek Konarzewski
- Institute of BiologyUniversity of BiałystokCiołkowskiego 1J, 15‐245, BiałystokPoland
| | - Marcin Czarnoleski
- Institute of Environmental SciencesJagiellonian UniversityGronostajowa7, 30‐387KrakówPoland
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25
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Feltham BA, Louis XL, Eskin MNA, Suh M. Docosahexaenoic Acid: Outlining the Therapeutic Nutrient Potential to Combat the Prenatal Alcohol-Induced Insults on Brain Development. Adv Nutr 2020; 11:724-735. [PMID: 31989167 PMCID: PMC7231602 DOI: 10.1093/advances/nmz135] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/05/2019] [Accepted: 12/22/2019] [Indexed: 01/20/2023] Open
Abstract
Brain development is markedly affected by prenatal alcohol exposure, leading to cognitive and behavioral problems in the children. Protecting neuronal damage from prenatal alcohol could improve neural connections and functioning of the brain. DHA, a n-3 (ω-3) long-chain PUFA, is involved in the development of neurons. Insufficient concentrations of DHA impair neuronal development and plasticity of synaptic junctions and affect neurotransmitter concentrations in the brain. Alcohol consumption during pregnancy decreases the maternal DHA status and reduces the placental transfer of DHA to the fetus, resulting in less DHA being available for brain development. It is important to know whether DHA could induce beneficial effects on various physiological functions that promote neuronal development. This review will discuss the current evidence for the beneficial role of DHA in protecting against neuronal damage and its potential in mitigating the teratogenic effects of alcohol.
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Affiliation(s)
- Bradley A Feltham
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Xavier L Louis
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Michael N A Eskin
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Miyoung Suh
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
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26
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Le Joncour V, Filppu P, Hyvönen M, Holopainen M, Turunen SP, Sihto H, Burghardt I, Joensuu H, Tynninen O, Jääskeläinen J, Weller M, Lehti K, Käkelä R, Laakkonen P. Vulnerability of invasive glioblastoma cells to lysosomal membrane destabilization. EMBO Mol Med 2020; 11:emmm.201809034. [PMID: 31068339 PMCID: PMC6554674 DOI: 10.15252/emmm.201809034] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The current clinical care of glioblastomas leaves behind invasive, radio‐ and chemo‐resistant cells. We recently identified mammary‐derived growth inhibitor (MDGI/FABP3) as a biomarker for invasive gliomas. Here, we demonstrate a novel function for MDGI in the maintenance of lysosomal membrane integrity, thus rendering invasive glioma cells unexpectedly vulnerable to lysosomal membrane destabilization. MDGI silencing impaired trafficking of polyunsaturated fatty acids into cells resulting in significant alterations in the lipid composition of lysosomal membranes, and subsequent death of the patient‐derived glioma cells via lysosomal membrane permeabilization (LMP). In a preclinical model, treatment of glioma‐bearing mice with an antihistaminergic LMP‐inducing drug efficiently eradicated invasive glioma cells and secondary tumours within the brain. This unexpected fragility of the aggressive infiltrating cells to LMP provides new opportunities for clinical interventions, such as re‐positioning of an established antihistamine drug, to eradicate the inoperable, invasive, and chemo‐resistant glioma cells from sustaining disease progression and recurrence.
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Affiliation(s)
- Vadim Le Joncour
- Translational Cancer Medicine Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pauliina Filppu
- Translational Cancer Medicine Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Maija Hyvönen
- Translational Cancer Medicine Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Minna Holopainen
- Helsinki University Lipidomics Unit, Helsinki Institute of Life Science (HiLIFE) and Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - S Pauliina Turunen
- Research Programs Unit, Genome-Scale Biology, University of Helsinki, Helsinki, Finland.,Department of Microbiology, Tumour and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Harri Sihto
- Translational Cancer Medicine Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Isabel Burghardt
- Department of Neurology and Brain Tumour Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Heikki Joensuu
- Translational Cancer Medicine Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Department of Oncology, Helsinki University Hospital, Helsinki, Finland
| | - Olli Tynninen
- Department of Pathology, Haartman Institute, University of Helsinki and HUSLAB, Helsinki, Finland
| | | | - Michael Weller
- Department of Neurology and Brain Tumour Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Kaisa Lehti
- Research Programs Unit, Genome-Scale Biology, University of Helsinki, Helsinki, Finland.,Department of Microbiology, Tumour and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Reijo Käkelä
- Helsinki University Lipidomics Unit, Helsinki Institute of Life Science (HiLIFE) and Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Pirjo Laakkonen
- Translational Cancer Medicine Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland .,Laboratory Animal Centre, Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
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27
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Bohannon BM, de la Cruz A, Wu X, Jowais JJ, Perez ME, Dykxhoorn DM, Liin SI, Larsson HP. Polyunsaturated fatty acid analogues differentially affect cardiac Na V, Ca V, and K V channels through unique mechanisms. eLife 2020; 9:51453. [PMID: 32207683 PMCID: PMC7159882 DOI: 10.7554/elife.51453] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 03/24/2020] [Indexed: 12/15/2022] Open
Abstract
The cardiac ventricular action potential depends on several voltage-gated ion channels, including NaV, CaV, and KV channels. Mutations in these channels can cause Long QT Syndrome (LQTS) which increases the risk for ventricular fibrillation and sudden cardiac death. Polyunsaturated fatty acids (PUFAs) have emerged as potential therapeutics for LQTS because they are modulators of voltage-gated ion channels. Here we demonstrate that PUFA analogues vary in their selectivity for human voltage-gated ion channels involved in the ventricular action potential. The effects of specific PUFA analogues range from selective for a specific ion channel to broadly modulating cardiac ion channels from all three families (NaV, CaV, and KV). In addition, a PUFA analogue selective for the cardiac IKs channel (Kv7.1/KCNE1) is effective in shortening the cardiac action potential in human-induced pluripotent stem cell-derived cardiomyocytes. Our data suggest that PUFA analogues could potentially be developed as therapeutics for LQTS and cardiac arrhythmia.
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Affiliation(s)
- Briana M Bohannon
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Alicia de la Cruz
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Xiaoan Wu
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Jessica J Jowais
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Marta E Perez
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Derek M Dykxhoorn
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, United States
| | - Sara I Liin
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - H Peter Larsson
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
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28
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Else PL. The highly unnatural fatty acid profile of cells in culture. Prog Lipid Res 2019; 77:101017. [PMID: 31809755 DOI: 10.1016/j.plipres.2019.101017] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 10/02/2019] [Accepted: 10/25/2019] [Indexed: 02/06/2023]
Abstract
The fatty acid profile of cells in culture are unlike those of natural cells with twice the monounsaturated (MUFA) and half the polyunsaturated fatty acids (PUFA) level (Mol%). This is not due to cell lines primarily being derived from cancers but is due to limited access to lipid and an inability to make PUFA de novo as vertebrate cells. Classic culture methods use media with 10% serum (the only exogenous source of lipid). Fetal bovine serum (FBS), the serum of choice has a low level of lipid and cholesterol compared to other sera and at 10% of media provides 2-3% of the fatty acid and cholesterol, 1% of the PUFA and 0.3% of the essential fatty acid linoleic acid (18:2n-6) available to cells in the body. Since vertebrate cell lines cannot make PUFA they synthesise MUFA, offsetting their PUFA deficit and reducing their fatty acid diversity. Stem and primary cells in culture appear to be similarly affected, with a rapid loss of their natural fatty acid compositions. The unnatural lipid composition of cells in culture has substantial implications for examining natural stems cell in culture, and for investigations of cellular mechanisms using cell lines based on the pervasive influence of fats.
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Affiliation(s)
- Paul L Else
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute (IHMRI), Wollongong, NSW 2522, Australia.
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29
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Sun D, Peyear TA, Bennett WFD, Andersen OS, Lightstone FC, Ingólfsson HI. Molecular Mechanism for Gramicidin Dimerization and Dissociation in Bilayers of Different Thickness. Biophys J 2019; 117:1831-1844. [PMID: 31676135 PMCID: PMC7018991 DOI: 10.1016/j.bpj.2019.09.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/01/2019] [Accepted: 09/04/2019] [Indexed: 01/01/2023] Open
Abstract
Membrane protein functions can be altered by subtle changes in the host lipid bilayer physical properties. Gramicidin channels have emerged as a powerful system for elucidating the underlying mechanisms of membrane protein function regulation through changes in bilayer properties, which are reflected in the thermodynamic equilibrium distribution between nonconducting gramicidin monomers and conducting bilayer-spanning dimers. To improve our understanding of how subtle changes in bilayer thickness alter the gramicidin monomer and dimer distributions, we performed extensive atomistic molecular dynamics simulations and fluorescence-quenching experiments on gramicidin A (gA). The free-energy calculations predicted a nonlinear coupling between the bilayer thickness and channel formation. The energetic barrier inhibiting gA channel formation was sharply increased in the thickest bilayer (1,2-dierucoyl-sn-glycero-3-phosphocholine). This prediction was corroborated by experimental results on gramicidin channel activity in bilayers of different thickness. To further explore the mechanism of channel formation, we performed extensive unbiased molecular dynamics simulations, which allowed us to observe spontaneous gA dimer formation in lipid bilayers. The simulations revealed structural rearrangements in the gA subunits and changes in lipid packing, as well as water reorganization, that occur during the dimerization process. Together, the simulations and experiments provide new, to our knowledge, insights into the process and mechanism of gramicidin channel formation, as a prototypical example of the bilayer regulation of membrane protein function.
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Affiliation(s)
- Delin Sun
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Thasin A Peyear
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York
| | - W F Drew Bennett
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Olaf S Andersen
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York
| | - Felice C Lightstone
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
| | - Helgi I Ingólfsson
- Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California.
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30
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Romero LO, Massey AE, Mata-Daboin AD, Sierra-Valdez FJ, Chauhan SC, Cordero-Morales JF, Vásquez V. Dietary fatty acids fine-tune Piezo1 mechanical response. Nat Commun 2019; 10:1200. [PMID: 30867417 PMCID: PMC6416271 DOI: 10.1038/s41467-019-09055-7] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/18/2019] [Indexed: 12/18/2022] Open
Abstract
Mechanosensitive ion channels rely on membrane composition to transduce physical stimuli into electrical signals. The Piezo1 channel mediates mechanoelectrical transduction and regulates crucial physiological processes, including vascular architecture and remodeling, cell migration, and erythrocyte volume. The identity of the membrane components that modulate Piezo1 function remain largely unknown. Using lipid profiling analyses, we here identify dietary fatty acids that tune Piezo1 mechanical response. We find that margaric acid, a saturated fatty acid present in dairy products and fish, inhibits Piezo1 activation and polyunsaturated fatty acids (PUFAs), present in fish oils, modulate channel inactivation. Force measurements reveal that margaric acid increases membrane bending stiffness, whereas PUFAs decrease it. We use fatty acid supplementation to abrogate the phenotype of gain-of-function Piezo1 mutations causing human dehydrated hereditary stomatocytosis. Beyond Piezo1, our findings demonstrate that cell-intrinsic lipid profile and changes in the fatty acid metabolism can dictate the cell's response to mechanical cues.
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Affiliation(s)
- Luis O Romero
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Andrew E Massey
- Department of Pharmaceutical Sciences and Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Ave., Memphis, TN, 38163, USA
| | - Alejandro D Mata-Daboin
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Francisco J Sierra-Valdez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
- Centro de Investigación Biomédica, Hospital Zambrano Hellion, TecSalud, Ave. Batallon de San Patricio 112, 66278, San Pedro Garza García, Nuevo León, Mexico
- Tecnólogico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501 Sur, 64849, Monterrey, Nuevo León, Mexico
| | - Subhash C Chauhan
- Department of Pharmaceutical Sciences and Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Ave., Memphis, TN, 38163, USA
| | - Julio F Cordero-Morales
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, 71S. Manassas St., Memphis, TN, 38163, USA.
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Kapoor R, Peyear TA, Koeppe RE, Andersen OS. Antidepressants are modifiers of lipid bilayer properties. J Gen Physiol 2019; 151:342-356. [PMID: 30796095 PMCID: PMC6400527 DOI: 10.1085/jgp.201812263] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/17/2019] [Indexed: 12/28/2022] Open
Abstract
The two major classes of antidepressants, tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs), inhibit neurotransmitter reuptake at synapses. They also have off-target effects on proteins other than neurotransmitter transporters, which may contribute to both desired changes in brain function and the development of side effects. Many proteins modulated by antidepressants are bilayer spanning and coupled to the bilayer through hydrophobic interactions such that the conformational changes underlying their function will perturb the surrounding lipid bilayer, with an energetic cost (ΔG def) that varies with changes in bilayer properties. Here, we test whether changes in ΔG def caused by amphiphilic antidepressants partitioning into the bilayer are sufficient to alter membrane protein function. Using gramicidin A (gA) channels to probe whether TCAs and SSRIs alter the bilayer contribution to the free energy difference for the gramicidin monomer⇔dimer equilibrium (representing a well-defined conformational transition), we find that antidepressants alter gA channel activity with varying potency and no stereospecificity but with different effects on bilayer elasticity and intrinsic curvature. Measuring the antidepressant partition coefficients using isothermal titration calorimetry (ITC) or cLogP shows that the bilayer-modifying potency is predicted quite well by the ITC-determined partition coefficients, and channel activity is doubled at an antidepressant/lipid mole ratio of 0.02-0.07. These results suggest a mechanism by which antidepressants could alter the function of diverse membrane proteins by partitioning into cell membranes and thereby altering the bilayer contribution to the energetics of membrane protein conformational changes.
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Affiliation(s)
- Ruchi Kapoor
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY
| | - Thasin A Peyear
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR
| | - Olaf S Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY
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32
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Zhang M, Peyear T, Patmanidis I, Greathouse DV, Marrink SJ, Andersen OS, Ingólfsson HI. Fluorinated Alcohols' Effects on Lipid Bilayer Properties. Biophys J 2018; 115:679-689. [PMID: 30077334 PMCID: PMC6104562 DOI: 10.1016/j.bpj.2018.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/23/2018] [Accepted: 07/02/2018] [Indexed: 12/21/2022] Open
Abstract
Fluorinated alcohols (fluoroalcohols) have physicochemical properties that make them excellent solvents of peptides, proteins, and other compounds. Like other alcohols, fluoroalcohols also alter membrane protein function and lipid bilayer properties and stability. Thus, the questions arise: how potent are fluoroalcohols as lipid-bilayer-perturbing compounds, could small residual amounts that remain after adding compounds dissolved in fluoroalcohols alter lipid bilayer properties sufficiently to affect membranes and membrane protein function, and do they behave like other alcohols? To address these questions, we used a gramicidin-based fluorescence assay to determine the bilayer-modifying potency of selected fluoroalcohols: trifluoroethanol (TFE), HFIP, and perfluoro-tert-butanol (PFTB). These fluoroalcohols alter bilayer properties in the low (PFTB) to high (TFE) mM range. Using the same assay, we determined the bilayer partitioning of the alcohols. When referenced to the aqueous concentrations, the fluoroalcohols are more bilayer perturbing than their nonfluorinated counterparts, with the largest fluoroalcohol, PFTB, being the most potent and the smallest, TFE, the least. When referenced to the mole fractions in the membrane, however, the fluoroalcohols have equal or lesser bilayer-perturbing potency than their nonfluorinated counterparts, with TFE being more bilayer perturbing than PFTB. We compared the fluoroalcohols' molecular level bilayer interactions using atomistic molecular dynamics simulations and showed how, at higher concentrations, they can cause bilayer breakdown using absorbance measurements and 31P nuclear magnetic resonance.
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Affiliation(s)
- Mike Zhang
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York; The Bronx High School of Science, New York City, New York
| | - Thasin Peyear
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York
| | - Ilias Patmanidis
- Groningen Biomolecular Science and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Denise V Greathouse
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas
| | - Siewert J Marrink
- Groningen Biomolecular Science and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
| | - Olaf S Andersen
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York.
| | - Helgi I Ingólfsson
- Department Physiology and Biophysics, Weill Cornell Medicine, New York City, New York; Groningen Biomolecular Science and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands; Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California.
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33
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Cordero-Morales JF, Vásquez V. How lipids contribute to ion channel function, a fat perspective on direct and indirect interactions. Curr Opin Struct Biol 2018; 51:92-98. [PMID: 29602157 PMCID: PMC6162190 DOI: 10.1016/j.sbi.2018.03.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/07/2018] [Accepted: 03/15/2018] [Indexed: 11/30/2022]
Abstract
Membrane lipid composition and remodeling influence the function of ion channels. Polyunsaturated fatty acids (PUFAs) and their derivatives modulate ion channel function; whether this effect occurs directly by binding to the protein or indirectly through alteration of membranes' mechanical properties has been difficult to distinguish. There are a large number of studies addressing the effect of fatty acids; recent structural and functional analyses have identified binding sites and provided further evidence for the role of the plasma membrane in ion channel function. Here, we review cation channels that do not share a common topology or lipid-binding signature sequence, but for which there are recent compelling data that support both direct and indirect modulation by PUFAs or their derivatives.
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Affiliation(s)
- Julio F Cordero-Morales
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Valeria Vásquez
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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34
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Dockendorff C, Gandhi DM, Kimball IH, Eum KS, Rusinova R, Ingólfsson HI, Kapoor R, Peyear T, Dodge MW, Martin SF, Aldrich RW, Andersen OS, Sack JT. Synthetic Analogues of the Snail Toxin 6-Bromo-2-mercaptotryptamine Dimer (BrMT) Reveal That Lipid Bilayer Perturbation Does Not Underlie Its Modulation of Voltage-Gated Potassium Channels. Biochemistry 2018; 57:2733-2743. [PMID: 29616558 PMCID: PMC6007853 DOI: 10.1021/acs.biochem.8b00292] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Drugs do not act solely by canonical ligand-receptor binding interactions. Amphiphilic drugs partition into membranes, thereby perturbing bulk lipid bilayer properties and possibly altering the function of membrane proteins. Distinguishing membrane perturbation from more direct protein-ligand interactions is an ongoing challenge in chemical biology. Herein, we present one strategy for doing so, using dimeric 6-bromo-2-mercaptotryptamine (BrMT) and synthetic analogues. BrMT is a chemically unstable marine snail toxin that has unique effects on voltage-gated K+ channel proteins, making it an attractive medicinal chemistry lead. BrMT is amphiphilic and perturbs lipid bilayers, raising the question of whether its action against K+ channels is merely a manifestation of membrane perturbation. To determine whether medicinal chemistry approaches to improve BrMT might be viable, we synthesized BrMT and 11 analogues and determined their activities in parallel assays measuring K+ channel activity and lipid bilayer properties. Structure-activity relationships were determined for modulation of the Kv1.4 channel, bilayer partitioning, and bilayer perturbation. Neither membrane partitioning nor bilayer perturbation correlates with K+ channel modulation. We conclude that BrMT's membrane interactions are not critical for its inhibition of Kv1.4 activation. Further, we found that alkyl or ether linkages can replace the chemically labile disulfide bond in the BrMT pharmacophore, and we identified additional regions of the scaffold that are amenable to chemical modification. Our work demonstrates a strategy for determining if drugs act by specific interactions or bilayer-dependent mechanisms, and chemically stable modulators of Kv1 channels are reported.
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Affiliation(s)
- Chris Dockendorff
- Department of Chemistry , Marquette University , P.O. Box 1881, Milwaukee , Wisconsin 53201-1881 , United States
| | - Disha M Gandhi
- Department of Chemistry , Marquette University , P.O. Box 1881, Milwaukee , Wisconsin 53201-1881 , United States
| | - Ian H Kimball
- Department of Physiology & Membrane Biology , University of California , 1 Shields Avenue , Davis , California 95616 , United States
| | - Kenneth S Eum
- Department of Physiology & Membrane Biology , University of California , 1 Shields Avenue , Davis , California 95616 , United States
| | - Radda Rusinova
- Department of Physiology and Biophysics , Weill Cornell Medical College , New York , New York 10065 , United States
| | - Helgi I Ingólfsson
- Department of Physiology and Biophysics , Weill Cornell Medical College , New York , New York 10065 , United States
| | - Ruchi Kapoor
- Department of Physiology and Biophysics , Weill Cornell Medical College , New York , New York 10065 , United States
| | - Thasin Peyear
- Department of Physiology and Biophysics , Weill Cornell Medical College , New York , New York 10065 , United States
| | - Matthew W Dodge
- Department of Chemistry , Marquette University , P.O. Box 1881, Milwaukee , Wisconsin 53201-1881 , United States
| | - Stephen F Martin
- Department of Chemistry , University of Texas at Austin , 1 University Station , Austin , Texas 78712 , United States
| | - Richard W Aldrich
- Department of Neuroscience , University of Texas at Austin , 1 University Station , Austin , Texas 78712 , United States
| | - Olaf S Andersen
- Department of Physiology and Biophysics , Weill Cornell Medical College , New York , New York 10065 , United States
| | - Jon T Sack
- Department of Physiology & Membrane Biology , University of California , 1 Shields Avenue , Davis , California 95616 , United States
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Kerdiles O, Layé S, Calon F. Omega-3 polyunsaturated fatty acids and brain health: Preclinical evidence for the prevention of neurodegenerative diseases. Trends Food Sci Technol 2017. [DOI: 10.1016/j.tifs.2017.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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36
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Herold KF, Andersen OS, Hemmings HC. Divergent effects of anesthetics on lipid bilayer properties and sodium channel function. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:617-626. [PMID: 28695248 DOI: 10.1007/s00249-017-1239-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 06/27/2017] [Accepted: 07/01/2017] [Indexed: 02/07/2023]
Abstract
General anesthetics revolutionized medicine by allowing surgeons to perform more complex and much longer procedures. This widely used class of drugs is essential to patient care, yet their exact molecular mechanism(s) are incompletely understood. One early hypothesis over a century ago proposed that nonspecific interactions of anesthetics with the lipid bilayer lead to changes in neuronal function via effects on membrane properties. This model was supported by the Meyer-Overton correlation between anesthetic potency and lipid solubility and despite more recent evidence for specific protein targets, in particular ion-channels, lipid bilayer-mediated effects of anesthetics is still under debate. We therefore tested a wide range of chemically diverse general anesthetics on lipid bilayer properties using a sensitive and functional gramicidin-based assay. None of the tested anesthetics altered lipid bilayer properties at clinically relevant concentrations. Some anesthetics did affect the bilayer, though only at high supratherapeutic concentrations, which are unlikely relevant for clinical anesthesia. These results suggest that anesthetics directly interact with membrane proteins without altering lipid bilayer properties at clinically relevant concentrations. Voltage-gated Na+ channels are potential anesthetic targets and various isoforms are inhibited by a wide range of volatile anesthetics. They inhibit channel function by reducing peak Na+ current and shifting steady-state inactivation toward more hyperpolarized potentials. Recent advances in crystallography of prokaryotic Na+ channels, which are sensitive to volatile anesthetics, together with molecular dynamics simulations and electrophysiological studies will help identify potential anesthetic interaction sites within the channel protein itself.
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Affiliation(s)
- Karl F Herold
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Olaf S Andersen
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Hugh C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, 10065, USA. .,Department of Pharmacology, Weill Cornell Medicine, New York, NY, 10065, USA.
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37
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Beaven AH, Maer AM, Sodt AJ, Rui H, Pastor RW, Andersen OS, Im W. Gramicidin A Channel Formation Induces Local Lipid Redistribution I: Experiment and Simulation. Biophys J 2017; 112:1185-1197. [PMID: 28355546 DOI: 10.1016/j.bpj.2017.01.028] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/11/2017] [Accepted: 01/30/2017] [Indexed: 10/19/2022] Open
Abstract
Integral membrane protein function can be modulated by the host bilayer. Because biological membranes are diverse and nonuniform, we explore the consequences of lipid diversity using gramicidin A channels embedded in phosphatidylcholine (PC) bilayers composed of equimolar mixtures of di-oleoyl-PC and di-erucoyl-PC (dC18:1+dC22:1, respectively), di-palmitoleoyl-PC and di-nervonoyl-PC (dC16:1+dC24:1, respectively), and di-eicosenoyl-PC (pure dC20:1), all of which have the same average bilayer chain length. Single-channel lifetime experiments, molecular dynamics simulations, and a simple lipid compression model are used in tandem to gain insight into lipid redistribution around the channel, which partially alleviates the bilayer deformation energy associated with channel formation. The average single-channel lifetimes in the two-component bilayers (95 ± 10 ms for dC18:1+dC22:1 and 195 ± 20 ms for dC16:1+dC24:1) were increased relative to the single-component dC20:1 control bilayer (65 ± 10 ms), implying lipid redistribution. Using a theoretical treatment of thickness-dependent changes in channel lifetimes, the effective local enrichment of lipids around the channel was estimated to be 58 ± 4% dC18:1 and 66 ± 2% dC16:1 in the dC18:1+dC22:1 and dC16:1+dC24:1 bilayers, respectively. 3.5-μs molecular dynamics simulations show 66 ± 2% dC16:1 in the first lipid shell around the channel in the dC16:1+dC24:1 bilayer, but no significant redistribution (50 ± 4% dC18:1) in the dC18:1+dC22:1 bilayer; these simulated values are within the 95% confidence intervals of the experimental averages. The strong preference for the better matching lipid (dC16:1) near the channel in the dC16:1+dC24:1 mixture and lesser redistribution in the dC18:1+dC22:1 mixture can be explained by the energetic cost associated with compressing the lipids to match the channel's hydrophobic length.
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Affiliation(s)
- Andrew H Beaven
- Department of Chemistry, The University of Kansas, Lawrence, Kansas
| | - Andreia M Maer
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York
| | - Alexander J Sodt
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Huan Rui
- Department of Biological Sciences and Bioengineering Program, Lehigh University, Bethlehem, Pennsylvania
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Olaf S Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York.
| | - Wonpil Im
- Department of Biological Sciences and Bioengineering Program, Lehigh University, Bethlehem, Pennsylvania.
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38
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Silva CO, Simões T, Novais SC, Pimparel I, Granada L, Soares AMVM, Barata C, Lemos MFL. Fatty acid profile of the sea snail Gibbula umbilicalis as a biomarker for coastal metal pollution. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 586:542-550. [PMID: 28202240 DOI: 10.1016/j.scitotenv.2017.02.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 02/03/2017] [Accepted: 02/03/2017] [Indexed: 06/06/2023]
Abstract
Metals are among the most common environmental pollutants with natural or anthropogenic origin that can be easily transferred through the food chain. Marine gastropods are known to accumulate high concentrations of these metals in their tissues. Gibbula umbilicalis ecological importance and abundant soft tissues, which enables extent biochemical assessments, makes this particular organism a potentially suitable species for marine ecotoxicological studies. Fatty acids are carbon-rich compounds that are ubiquitous in all organisms and easy to metabolize. Their biological specificity, relatively well-studied functions and importance, and the fact that they may alter when stress is induced, make fatty acids prospect biomarkers. This work aimed to assess fatty acid profile changes in the gastropod G. umbilicalis exposed to three metal contaminants. After a 168h exposure to cadmium, mercury, and nickel, the following lipid related endpoints were measured: total lipid content; lipid peroxidation; and fatty acid profile (FAP). The analysis of the FAP suggested an alteration in the fatty acid metabolism and indicated a link between metals exposure and homeoviscous adaptation and immune response. In particular, five fatty acids (palmitic, eicosatrienoic, arachidonic, eicosapentaenoic, and docosahexaenoic acids), demonstrated to be especially good indicators of G. umbilicalis responses to the array of metals used, having thus the potential to be used as biomarkers for metal contamination in this species. This work represents a first approach for the use of FAP signature as a sensitive and informative parameter and novel tool in environmental risk assessment (ERA) of coastal environments, using G. umbilicalis as model species.
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Affiliation(s)
- Carla O Silva
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520-641 Peniche, Portugal.
| | - Tiago Simões
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520-641 Peniche, Portugal; Department of Ecological Science, Vrije University, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - Sara C Novais
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520-641 Peniche, Portugal; Department of Ecological Science, Vrije University, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands
| | - Inês Pimparel
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520-641 Peniche, Portugal
| | - Luana Granada
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520-641 Peniche, Portugal
| | - Amadeu M V M Soares
- Department of Biology and CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Aveiro, Portugal
| | - Carlos Barata
- Environmental Chemistry Department, IDAEA-CSIC, Jordi Girona 18-26, 08034, Barcelona, Spain
| | - Marco F L Lemos
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520-641 Peniche, Portugal
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Basak S, Schmandt N, Gicheru Y, Chakrapani S. Crystal structure and dynamics of a lipid-induced potential desensitized-state of a pentameric ligand-gated channel. eLife 2017; 6:23886. [PMID: 28262093 PMCID: PMC5378477 DOI: 10.7554/elife.23886] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 03/04/2017] [Indexed: 12/14/2022] Open
Abstract
Desensitization in pentameric ligand-gated ion channels plays an important role in regulating neuronal excitability. Here, we show that docosahexaenoic acid (DHA), a key ω−3 polyunsaturated fatty acid in synaptic membranes, enhances the agonist-induced transition to the desensitized state in the prokaryotic channel GLIC. We determined a 3.25 Å crystal structure of the GLIC-DHA complex in a potentially desensitized conformation. The DHA molecule is bound at the channel-periphery near the M4 helix and exerts a long-range allosteric effect on the pore across domain-interfaces. In this previously unobserved conformation, the extracellular-half of the pore-lining M2 is splayed open, reminiscent of the open conformation, while the intracellular-half is constricted, leading to a loss of both water and permeant ions. These findings, in combination with spin-labeling/EPR spectroscopic measurements in reconstituted-membranes, provide novel mechanistic details of desensitization in pentameric channels. DOI:http://dx.doi.org/10.7554/eLife.23886.001 The nerve cells (or neurons) in the brain communicate with each other by releasing chemicals called neurotransmitters that bind to ion channels on neighboring neurons. This ultimately causes ions to flow in or out of the receiving neuron through these ion channels; this ion flow determines how the neuron responds. One family of ion channels that is found at the junction between neurons, and between neurons and muscle fibers, is known as the pentameric ligand-gated ion channels (or pLGICs). These channels act as ‘gates’ that open to allow ions through them when a neurotransmitter binds to the channel. In addition to the open ‘active’ state, the channels can take on two different ‘inactive’ states that do not allow ions to pass through the channel: a closed (resting) state and a desensitized state (that is still bound to the neurotransmitter). Understanding how channels switch between these states is important for designing drugs that correct problems that cause the channels to work incorrectly. Problems that affect the desensitized state have been linked to neurological disorders such as epilepsy. Medically important molecules such as anesthetics and alcohols are thought to affect desensitization, and drugs that target desensitized ion channels may present ways of treating neurological disorders with fewer side effects. Docosahexaenoic acid (DHA) is an abundant lipid molecule that is present in the membranes of neurons. It is one of the key ingredients in fish oil supplements and is thought to enhance learning and memory. DHA affects the desensitization of pLGICs but it is not clear exactly how it does so. Basak et al. now show that DHA affects a bacterial pLGIC in the same way as it affects human channels – by enhancing desensitization. Using a technique called X-ray crystallography to analyze the channel while bound to DHA revealed a previously unobserved channel structure. The DHA molecule binds to a site at the edge of the channel and causes a change in its structure that leaves the upper part of the channel open while the lower part is constricted. Basak et al. predict that molecules such as anesthetics target this desensitized state. The next step will be to obtain the structures of bacterial and human pLGIC channels in a natural membrane environment. This will allow us to better understand the changes in structure that the channels go through as they transmit signals between neurons, and so help in the development of new treatments for neurological disorders. DOI:http://dx.doi.org/10.7554/eLife.23886.002
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Affiliation(s)
- Sandip Basak
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, United States
| | - Nicolaus Schmandt
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, United States
| | - Yvonne Gicheru
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, United States
| | - Sudha Chakrapani
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, United States
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40
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Clinical concentrations of chemically diverse general anesthetics minimally affect lipid bilayer properties. Proc Natl Acad Sci U S A 2017; 114:3109-3114. [PMID: 28265069 DOI: 10.1073/pnas.1611717114] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
General anesthetics have revolutionized medicine by facilitating invasive procedures, and have thus become essential drugs. However, detailed understanding of their molecular mechanisms remains elusive. A mechanism proposed over a century ago involving unspecified interactions with the lipid bilayer known as the unitary lipid-based hypothesis of anesthetic action, has been challenged by evidence for direct anesthetic interactions with a range of proteins, including transmembrane ion channels. Anesthetic concentrations in the membrane are high (10-100 mM), however, and there is no experimental evidence ruling out a role for the lipid bilayer in their ion channel effects. A recent hypothesis proposes that anesthetic-induced changes in ion channel function result from changes in bilayer lateral pressure that arise from partitioning of anesthetics into the bilayer. We examined the effects of a broad range of chemically diverse general anesthetics and related nonanesthetics on lipid bilayer properties using an established fluorescence assay that senses drug-induced changes in lipid bilayer properties. None of the compounds tested altered bilayer properties sufficiently to produce meaningful changes in ion channel function at clinically relevant concentrations. Even supra-anesthetic concentrations caused minimal bilayer effects, although much higher (toxic) concentrations of certain anesthetic agents did alter lipid bilayer properties. We conclude that general anesthetics have minimal effects on bilayer properties at clinically relevant concentrations, indicating that anesthetic effects on ion channel function are not bilayer-mediated but rather involve direct protein interactions.
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Medeiros D, Silva-Gonçalves LDC, da Silva AMB, Dos Santos Cabrera MP, Arcisio-Miranda M. Membrane-mediated action of the endocannabinoid anandamide on membrane proteins: implications for understanding the receptor-independent mechanism. Sci Rep 2017; 7:41362. [PMID: 28128290 PMCID: PMC5269673 DOI: 10.1038/srep41362] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 12/20/2016] [Indexed: 12/31/2022] Open
Abstract
Endocannabinoids are amphiphilic molecules that play crucial neurophysiological functions acting as lipid messengers. Antagonists and knockdown of the classical CB1 and CB2 cannabinoid receptors do not completely abolish many endocannabinoid activities, supporting the idea of a mechanism independent of receptors whose mode of action remains unclear. Here we combine gramicidin A (gA) single channel recordings and membrane capacitance measurements to investigate the lipid bilayer-modifying activity of endocannabinoids. Single channel recordings show that the incorporation of endocannabinoids into lipid bilayers reduces the free energy necessary for gramicidin channels to transit from the monomeric to the dimeric conformation. Membrane capacitance demonstrates that the endocannabinoid anandamide has limited effects on the overall structure of the lipid bilayers. Our results associated with the theory of membrane elastic deformation reveal that the action of endocannabinoids on membrane proteins can involve local adjustments of the lipid/protein hydrophobic interface. The current findings shed new light on the receptor-independent mode of action of endocannabinoids on membrane proteins, with important implications towards their neurobiological function.
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Affiliation(s)
- Djalma Medeiros
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil.,Curso de Filosofia, Faculdade de São Bento, São Paulo, SP, Brasil
| | - Laíz da Costa Silva-Gonçalves
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - Annielle Mendes Brito da Silva
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | | | - Manoel Arcisio-Miranda
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil
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42
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Mechanical properties that influence antimicrobial peptide activity in lipid membranes. Appl Microbiol Biotechnol 2016; 100:10251-10263. [DOI: 10.1007/s00253-016-7975-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 01/22/2023]
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43
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Duro N, Gjika M, Siddiqui A, Scott HL, Varma S. POPC Bilayers Supported on Nanoporous Substrates: Specific Effects of Silica-Type Surface Hydroxylation and Charge Density. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:6766-6774. [PMID: 27283467 DOI: 10.1021/acs.langmuir.6b01155] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent advances in nanotechnology bring to the forefront a new class of extrinsic constraints for remodeling lipid bilayers. In this next-generation technology, membranes are supported over nanoporous substrates. The nanometer-sized pores in the substrate are too small for bilayers to follow the substrate topology; consequently, the bilayers hang over the pores. Experiments demonstrate that nanoporous substrates remodel lipid bilayers differently from continuous substrates. The underlying molecular mechanisms, however, remain largely undetermined. Here we use molecular dynamics (MD) simulations to probe the effects of silica-type hydroxylation and charge densities on adsorbed palmitoyl-oleoylphosphatidylcholine (POPC) bilayers. We find that a 50% porous substrate decorated with a surface density of 4.6 hydroxyls/nm(2) adsorbs a POPC bilayer at a distance of 4.5 Å, a result consistent with neutron reflectivity experiments conducted on topologically similar silica constructs under highly acidic conditions. Although such an adsorption distance suggests that the interaction between the bilayer and the substrate will be buffered by water molecules, we find that the substrate does interact directly with the bilayer. The substrate modifies several properties of the bilayer-it dampens transverse lipid fluctuations, reduces lipid diffusion rates, and modifies transverse charge densities significantly. Additionally, it affects lipid properties differently in the two leaflets. Compared to substrates functionalized with sparser surface hydroxylation densities, this substrate adheres to bilayers at smaller distances and also remodels POPC more extensively, suggesting a direct correspondence between substrate hydrophilicity and membrane properties. A partial deprotonation of surface hydroxyls, as expected of a silica substrate under mildly acidic conditions, however, produces an inverse effect: it increases the substrate-bilayer distance, which we attribute to the formation of an electric double layer over the negatively charged substrate, and restores, at least partially, leaflet asymmetry and headgroup orientations. Overall, this study highlights the intrinsic complexity of lipid-substrate interactions and suggests the prospect of making two surface attributes-dipole densities and charge densities-work antagonistically toward remodeling lipid bilayer properties.
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Affiliation(s)
- Nalvi Duro
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida , Tampa, Florida 33620, United States
| | - Marion Gjika
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida , Tampa, Florida 33620, United States
| | - Ahnaf Siddiqui
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida , Tampa, Florida 33620, United States
| | - H Larry Scott
- Department of Physics, Illinois Institute of Technology , Chicago, Illinois 60616, United States
| | - Sameer Varma
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida , Tampa, Florida 33620, United States
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Kawanabe A, Okamura Y. Effects of unsaturated fatty acids on the kinetics of voltage-gated proton channels heterologously expressed in cultured cells. J Physiol 2016; 594:595-610. [PMID: 26563684 DOI: 10.1113/jp271274] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/28/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Arachidonic acid (AA) greatly enhances the activity of the voltage-gated proton (Hv) channel, although its mechanism of action and physiological function remain unclear. In the present study, we analysed the effects of AA on proton currents through Hv channels heterologously expressed in HEK293T cells. The dramatic increase in proton current amplitude elicited by AA was accompanied by accelerated activation kinetics and a leftward shift in the voltage-dependence of activation. Mutagenesis studies suggest the two aforementioned effects of AA reflect two distinct structural mechanisms. Application of phospholipase A2 , which liberates AA from phospholipids in the membrane, also enhances Hv channel activity, supporting the idea that AA modulates Hv channel activity within physiological contexts. Unsaturated fatty acids are key components of the biological membranes of all cells, and precursors of mediators for cell signalling. Arachidonic acid (AA) is an unsaturated fatty acid known to modulate the activities of various ion channels, including the voltage-gated proton (Hv) channel, which supports the rapid production of reactive oxygen species (ROS) in phagocytes through regulation of pH and membrane potential. However, the molecular mechanisms and physiological functions of the effects of AA on Hv channels remain unclear. In the present study, we report an electrophysiological analysis of the effects of AA on the mouse Hv channel (mHv1) heterologously expressed in HEK293T cells. Application of AA to excised inside-out patch membranes rapidly induced a robust increase in the amplitude of the proton current through mHv1. The current increase was accompanied by accelerated activation kinetics and a small leftward shift of the current-voltage relationship. In monomeric channels lacking the coiled-coil region of the channel protein, the shift in the current-voltage relationship was diminished but activation and deactivation remained accelerated. Studies with several AA derivatives showed that double bonds and hydrophilic head groups are essential for the effect of AA, although charge was not important. The application of phospholipase A2 (PLA2), which generates AA from cell membrane phospholipids, stimulated mHv1 activity to a similar extent as direct application of ∼ 20 μM AA, suggesting that endogenous AA may regulate Hv channel activity.
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Affiliation(s)
- Akira Kawanabe
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Yasushi Okamura
- Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
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45
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Rusinova R, Koeppe RE, Andersen OS. A general mechanism for drug promiscuity: Studies with amiodarone and other antiarrhythmics. ACTA ACUST UNITED AC 2015; 146:463-75. [PMID: 26573624 PMCID: PMC4664825 DOI: 10.1085/jgp.201511470] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/13/2015] [Indexed: 01/14/2023]
Abstract
Amiodarone is a widely prescribed antiarrhythmic drug used to treat the most prevalent type of arrhythmia, atrial fibrillation (AF). At therapeutic concentrations, amiodarone alters the function of many diverse membrane proteins, which results in complex therapeutic and toxicity profiles. Other antiarrhythmics, such as dronedarone, similarly alter the function of multiple membrane proteins, suggesting that a multipronged mechanism may be beneficial for treating AF, but raising questions about how these antiarrhythmics regulate a diverse range of membrane proteins at similar concentrations. One possible mechanism is that these molecules regulate membrane protein function by altering the common environment provided by the host lipid bilayer. We took advantage of the gramicidin (gA) channels' sensitivity to changes in bilayer properties to determine whether commonly used antiarrhythmics--amiodarone, dronedarone, propranolol, and pindolol, whose pharmacological modes of action range from multi-target to specific--perturb lipid bilayer properties at therapeutic concentrations. Using a gA-based fluorescence assay, we found that amiodarone and dronedarone are potent bilayer modifiers at therapeutic concentrations; propranolol alters bilayer properties only at supratherapeutic concentration, and pindolol has little effect. Using single-channel electrophysiology, we found that amiodarone and dronedarone, but not propranolol or pindolol, increase bilayer elasticity. The overlap between therapeutic and bilayer-altering concentrations, which is observed also using plasma membrane-like lipid mixtures, underscores the need to explore the role of the bilayer in therapeutic as well as toxic effects of antiarrhythmic agents.
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Affiliation(s)
- Radda Rusinova
- Department of Physiology and Biophysics and Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065 Department of Physiology and Biophysics and Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701
| | - Olaf S Andersen
- Department of Physiology and Biophysics and Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
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Abstract
Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all.
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Affiliation(s)
- Nicole B. Ramsey
- Weill Cornell/Rockefeller/Sloan-Kettering Tri-Institutional MD-PhD Program, New York, NY, United States of America
- Graduate Program in Pharmacology, Weill Cornell Graduate School of Medical Sciences, New York, NY, United States of America
| | - Olaf S. Andersen
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States of America
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47
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Bazzano M, Rizzo M, Arfuso F, Giannetto C, Fazio F, Piccione G. Increase in erythrocyte osmotic resistance following polyunsaturated fatty acids (PUFA) supplementation in show jumper horses. Livest Sci 2015. [DOI: 10.1016/j.livsci.2015.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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n-3 polyunsaturated fatty acids suppress CD4(+) T cell proliferation by altering phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:85-96. [PMID: 26476105 DOI: 10.1016/j.bbamem.2015.10.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 02/07/2023]
Abstract
The mechanisms by which n-3 polyunsaturated fatty acids (n-3 PUFA), abundant in fish oil, exert their anti-inflammatory effects have not been rigorously defined. We have previously demonstrated that n-3 PUFA decrease the amount of phosphatidylinositol-(4,5)-bisphosphate, [PI(4,5)P2], in CD4(+) T cells, leading to suppressed actin remodeling upon activation. Since discrete pools of PI(4,5)P2 exist in the plasma membrane, we determined whether n-3 PUFA modulate spatial organization of PI(4,5)P2 relative to raft and non-raft domains. We used Förster resonance energy transfer (FRET) to demonstrate that lipid raft mesodomains in the plasma membrane of CD4(+) T cells enriched in n-3 PUFA display increased co-clustering of Lck(N10) and LAT(ΔCP), markers of lipid rafts. CD4(+) T cells enriched in n-3 PUFA also exhibited a depleted plasma membrane non-raft PI(4,5)P2 pool as detected by decreased co-clustering of Src(N15), a non-raft marker, and PH(PLC-δ), a PI(4,5)P2 reporter. Incubation with exogenous PI(4,5)P2 rescued the effects on the non-raft PI(4,5)P2 pool, and reversed the suppression of T cell proliferation in CD4(+) T cells enriched with n-3 PUFA. Furthermore, CD4(+) T cells isolated from mice fed a 4% docosahexaenoic acid (DHA)-enriched diet exhibited a decrease in the non-raft pool of PI(4,5)P2, and exogenous PI(4,5)P2 reversed the suppression of T cell proliferation. Finally, these effects were not due to changes to post-translational lipidation, since n-3 PUFA did not alter the palmitoylation status of signaling proteins. These data demonstrate that n-3 PUFA suppress T cell proliferation by altering plasma membrane topography and the spatial organization of PI(4,5)P2.
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49
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Galimzyanov TR, Molotkovsky RJ, Bozdaganyan ME, Cohen FS, Pohl P, Akimov SA. Elastic Membrane Deformations Govern Interleaflet Coupling of Lipid-Ordered Domains. PHYSICAL REVIEW LETTERS 2015; 115:088101. [PMID: 26340212 PMCID: PMC4750487 DOI: 10.1103/physrevlett.115.088101] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Indexed: 05/19/2023]
Abstract
The mechanism responsible for domain registration in two membrane leaflets has thus far remained enigmatic. Using continuum elasticity theory, we show that minimum line tension is achieved along the rim between thicker (ordered) and thinner (disordered) domains by shifting the rims in opposing leaflets by a few nanometers relative to each other. Increasing surface tension yields an increase in line tension, resulting in larger domains. Because domain registration is driven by lipid deformation energy, it does not require special lipid components or interactions at the membrane midplane.
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Affiliation(s)
- Timur R Galimzyanov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/5 Leninskiy prospekt, Moscow 119071, Russia
- National University of Science and Technology "MISiS", 4 Leninskiy prospekt, Moscow 119049, Russia
| | - Rodion J Molotkovsky
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/5 Leninskiy prospekt, Moscow 119071, Russia
| | - Marine E Bozdaganyan
- M.V. Lomonosov Moscow State University, 1 Leninskie Gory, Moscow 119991, Russia
- Federal Research Clinical Center of the Specialized Types of Health Care and Medical Technologies FMBA of Russia, 28 Orekhovyi bulvar, Moscow 115692, Russia
| | - Fredric S Cohen
- Rush University Medical Center, 1750 W. Harrison Street, Chicago, Illinois 60612, USA
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40-42, Linz 4020, Austria
| | - Sergey A Akimov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31/5 Leninskiy prospekt, Moscow 119071, Russia
- National University of Science and Technology "MISiS", 4 Leninskiy prospekt, Moscow 119049, Russia
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50
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Hou TY, McMurray DN, Chapkin RS. Omega-3 fatty acids, lipid rafts, and T cell signaling. Eur J Pharmacol 2015; 785:2-9. [PMID: 26001374 DOI: 10.1016/j.ejphar.2015.03.091] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 02/16/2015] [Accepted: 03/16/2015] [Indexed: 12/24/2022]
Abstract
n-3 polyunsaturated fatty acids (PUFA) have been shown in many clinical studies to attenuate inflammatory responses. Although inflammatory responses are orchestrated by a wide spectrum of cells, CD4(+) T cells play an important role in the etiology of many chronic inflammatory diseases such as inflammatory bowel disease and obesity. In light of recent concerns over the safety profiles of non-steroidal anti-inflammatory drugs (NSAIDs), alternatives such as bioactive nutraceuticals are becoming more attractive. In order for these agents to be accepted into mainstream medicine, however, the mechanisms by which nutraceuticals such as n-3 PUFA exert their anti-inflammatory effects must be fully elucidated. Lipid rafts are nanoscale, dynamic domains in the plasma membrane that are formed through favorable lipid-lipid (cholesterol, sphingolipids, and saturated fatty acids) and lipid-protein (membrane-actin cytoskeleton) interactions. These domains optimize the clustering of signaling proteins at the membrane to facilitate efficient cell signaling which is required for CD4(+) T cell activation and differentiation. This review summarizes novel emerging data documenting the ability of n-3 PUFA to perturb membrane-cytoskeletal structure and function in CD4(+) T cells. An understanding of these underlying mechanisms will provide a rationale for the use of n-3 PUFA in the treatment of chronic inflammation.
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Affiliation(s)
- Tim Y Hou
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA
| | - David N McMurray
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University System Health Science Center, College Station, TX, USA
| | - Robert S Chapkin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA; Department of Nutrition and Food Science, Texas A&M University, College Station, TX, USA; Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Center for Translational Environmental Health Research, Texas A&M University, College Station, TX, USA; Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA; Department of Microbial Pathogenesis and Immunology, Texas A&M University System Health Science Center, College Station, TX, USA.
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