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Borsley S, Leigh DA, Roberts BMW. Molecular Ratchets and Kinetic Asymmetry: Giving Chemistry Direction. Angew Chem Int Ed Engl 2024; 63:e202400495. [PMID: 38568047 DOI: 10.1002/anie.202400495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Indexed: 05/03/2024]
Abstract
Over the last two decades ratchet mechanisms have transformed the understanding and design of stochastic molecular systems-biological, chemical and physical-in a move away from the mechanical macroscopic analogies that dominated thinking regarding molecular dynamics in the 1990s and early 2000s (e.g. pistons, springs, etc), to the more scale-relevant concepts that underpin out-of-equilibrium research in the molecular sciences today. Ratcheting has established molecular nanotechnology as a research frontier for energy transduction and metabolism, and has enabled the reverse engineering of biomolecular machinery, delivering insights into how molecules 'walk' and track-based synthesisers operate, how the acceleration of chemical reactions enables energy to be transduced by catalysts (both motor proteins and synthetic catalysts), and how dynamic systems can be driven away from equilibrium through catalysis. The recognition of molecular ratchet mechanisms in biology, and their invention in synthetic systems, is proving significant in areas as diverse as supramolecular chemistry, systems chemistry, dynamic covalent chemistry, DNA nanotechnology, polymer and materials science, molecular biology, heterogeneous catalysis, endergonic synthesis, the origin of life, and many other branches of chemical science. Put simply, ratchet mechanisms give chemistry direction. Kinetic asymmetry, the key feature of ratcheting, is the dynamic counterpart of structural asymmetry (i.e. chirality). Given the ubiquity of ratchet mechanisms in endergonic chemical processes in biology, and their significance for behaviour and function from systems to synthesis, it is surely just as fundamentally important. This Review charts the recognition, invention and development of molecular ratchets, focussing particularly on the role for which they were originally envisaged in chemistry, as design elements for molecular machinery. Different kinetically asymmetric systems are compared, and the consequences of their dynamic behaviour discussed. These archetypal examples demonstrate how chemical systems can be driven inexorably away from equilibrium, rather than relax towards it.
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Affiliation(s)
- Stefan Borsley
- Department of Chemistry, The University of Manchester, Oxford Road, M13 9PL, Manchester, United Kingdom
| | - David A Leigh
- Department of Chemistry, The University of Manchester, Oxford Road, M13 9PL, Manchester, United Kingdom
| | - Benjamin M W Roberts
- Department of Chemistry, The University of Manchester, Oxford Road, M13 9PL, Manchester, United Kingdom
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2
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Zirpoli H, Bernis ME, Sabir H, Manual Kollareth DJ, Hamilton JA, Huang N, Ng J, Sosunov SA, Gaebler B, Ten VS, Deckelbaum RJ. Omega-3 fatty acid diglyceride emulsions as a novel injectable acute therapeutic in neonatal hypoxic-ischemic brain injury. Biomed Pharmacother 2024; 175:116749. [PMID: 38761420 PMCID: PMC11156760 DOI: 10.1016/j.biopha.2024.116749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/20/2024] Open
Abstract
Hypoxic-ischemic encephalopathy (HIE), resulting from a lack of blood flow and oxygen before or during newborn delivery, is a leading cause of cerebral palsy and neurological disability in children. Therapeutic hypothermia (TH), the current standard of care in HIE, is only beneficial in 1 of 7-8 cases. Therefore, there is a critical need for more efficient treatments. We have previously reported that omega-3 (n-3) fatty acids (FA) carried by triglyceride (TG) lipid emulsions provide neuroprotection after experimental hypoxic-ischemic (HI) injury in neonatal mice. Herein, we propose a novel acute therapeutic approach using an n-3 diglyceride (DG) lipid emulsions. Importantly, n-3 DG preparations had much smaller particle size compared to commercially available or lab-made n-3 TG emulsions. We showed that n-3 DG molecules have the advantage of incorporating at substantially higher levels than n-3 TG into an in vitro model of phospholipid membranes. We also observed that n-3 DG after parenteral administration in neonatal mice reaches the bloodstream more rapidly than n-3 TG. Using neonatal HI brain injury models in mice and rats, we found that n-3 DG emulsions provide superior neuroprotection than n-3 TG emulsions or TH in decreasing brain infarct size. Additionally, we found that n-3 DGs attenuate microgliosis and astrogliosis. Thus, n-3 DG emulsions are a superior, promising, and novel therapy for treating HIE.
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Affiliation(s)
- Hylde Zirpoli
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA.
| | - Maria Eugenia Bernis
- Department of Neonatology and Pediatric Intensive Care, Children's Hospital, University of Bonn, Germany; Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn 53127, Germany
| | - Hemmen Sabir
- Department of Neonatology and Pediatric Intensive Care, Children's Hospital, University of Bonn, Germany; Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn 53127, Germany
| | - Denny Joseph Manual Kollareth
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - James A Hamilton
- Department of Physiology & Biophysics, Department of Biomedical Engineering, Boston University School of Medicine, Boston, MA 02215, USA
| | - Nasi Huang
- Department of Physiology & Biophysics, Department of Biomedical Engineering, Boston University School of Medicine, Boston, MA 02215, USA
| | - Jesse Ng
- Department of Physiology & Biophysics, Department of Biomedical Engineering, Boston University School of Medicine, Boston, MA 02215, USA
| | - Sergey A Sosunov
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Neonatology, Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | | | - Vadim S Ten
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Neonatology, Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Richard J Deckelbaum
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
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Cao Y, Zhu J, Kou J, Tieleman DP, Liang Q. Unveiling Interactions of Tumor-Targeting Nanoparticles with Lipid Bilayers Using a Titratable Martini Model. J Chem Theory Comput 2024; 20:4045-4053. [PMID: 38648670 DOI: 10.1021/acs.jctc.4c00231] [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: 04/25/2024]
Abstract
pH-responsive nanoparticles are ideal vehicles for drug delivery and are widely used in cell imaging in targeted therapy of cancer, which usually has a weakly acidic microenvironment. In this work, we constructed a titratable molecular model for nanoparticles grafted with ligands of pH-sensitive carboxylic acids and investigated the interactions between the nanoparticles and the lipid bilayer in varying pH environments. We mainly examined the effect of the grafting density of the pH-sensitive ligands of the nanoparticles on the interactions of the nanoparticles with the lipid bilayer. The results show that the nanoparticles can penetrate the lipid bilayer only when the pH value is lower than a critical value, which can be readily modulated to the specific pH value of the tumor microenvironment by changing the ligand grafting density. This work provides some insights into modulating the interactions between the pH-sensitive nanoparticles and cellular membranes to realize targeted drug delivery to tumors based on their specific pH environment.
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Affiliation(s)
- Yu Cao
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Jin Zhu
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Jianlong Kou
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Science, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Qing Liang
- Center for Statistical and Theoretical Condensed Matter Physics & Department of Physics, Zhejiang Normal University, Jinhua 321004, China
- Zhejiang Institute of Photoelectronics & Zhejiang Institute for Advanced Light Source, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
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Abstract
Cancers undergo sequential changes to proton (H+) concentration and sensing that are consequences of the disease and facilitate its further progression. The impact of protonation state on protein activity can arise from alterations to amino acids or their titration. Indeed, many cancer-initiating mutations influence pH balance, regulation or sensing in a manner that enables growth and invasion outside normal constraints as part of oncogenic transformation. These cancer-supporting effects become more prominent when tumours develop an acidic microenvironment owing to metabolic reprogramming and disordered perfusion. The ensuing intracellular and extracellular pH disturbances affect multiple aspects of tumour biology, ranging from proliferation to immune surveillance, and can even facilitate further mutagenesis. As a selection pressure, extracellular acidosis accelerates disease progression by favouring acid-resistant cancer cells, which are typically associated with aggressive phenotypes. Although acid-base disturbances in tumours often occur alongside hypoxia and lactate accumulation, there is now ample evidence for a distinct role of H+-operated responses in key events underpinning cancer. The breadth of these actions presents therapeutic opportunities to change the trajectory of disease.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
| | - Stine Falsig Pedersen
- Department of Biology, University of Copenhagen, University of Copenhagen, Faculty of Science, København, Denmark.
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5
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Tempra C, Brkljača Z, Vazdar M. Why do polyarginines adsorb at neutral phospholipid bilayers and polylysines do not? An insight from density functional theory calculations and molecular dynamics simulations. Phys Chem Chem Phys 2023; 25:27204-27214. [PMID: 37791394 DOI: 10.1039/d3cp02411c] [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: 10/05/2023]
Abstract
Adsorption of cell-penetrating peptides (CPPs) at cellular membranes is the first and necessary step for their subsequent translocation across cellular membranes into the cytosol. It has been experimentally shown that CPPs rich in arginine (Arg) amino acid penetrate across phospholipid bilayers more effectively than their lysine (Lys) rich counterparts. In this work, we aim to understand the differences in the first translocation step, adsorption of Arg9 and Lys9 peptides at fully hydrated neutral phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipid bilayers and evaluate in detail the energetics of the process using molecular dynamics (MD) simulations and free energy calculations of adsorption of the single peptide. We show that the adsorption of Arg9 is energetically feasible, with the free energy of adsorption being ∼-5.0 kcal mol-1 at PC and ∼-5.5 kcal mol-1 at PE bilayers. In contrast, adsorption of Lys9 is not observed at PC bilayers, and their adsorption at PE bilayers is very weak, being ∼-0.5 kcal mol-1. We show by energy decomposition and analysis of peptide hydration along the membrane that significantly stronger electrostatic interactions of Arg9 with lipid phosphate groups, together with the greater loss of peptide hydration (and in turn stronger hydrophobic interactions) along the membrane translocation path, are the main driving factors governing the adsorption of Arg-rich peptides at neutral lipid bilayers in contrast to Lys-rich peptides. Finally, we also compare the energetics in lipid/bilayer systems with the density functional theory (DFT) calculations of the corresponding model systems in the continuum water model and reveal the energetic differences in different environments.
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Affiliation(s)
- Carmelo Tempra
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 542/2, 16000 Prague, Czech Republic
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Mario Vazdar
- Department of Mathematics, Informatics, and Cybernetics, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic.
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6
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Kreiter J, Škulj S, Brkljača Z, Bardakji S, Vazdar M, Pohl EE. FA Sliding as the Mechanism for the ANT1-Mediated Fatty Acid Anion Transport in Lipid Bilayers. Int J Mol Sci 2023; 24:13701. [PMID: 37762012 PMCID: PMC10531397 DOI: 10.3390/ijms241813701] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Mitochondrial adenine nucleotide translocase (ANT) exchanges ADP for ATP to maintain energy production in the cell. Its protonophoric function in the presence of long-chain fatty acids (FA) is also recognized. Our previous results imply that proton/FA transport can be best described with the FA cycling model, in which protonated FA transports the proton to the mitochondrial matrix. The mechanism by which ANT1 transports FA anions back to the intermembrane space remains unclear. Using a combined approach involving measurements of the current through the planar lipid bilayers reconstituted with ANT1, site-directed mutagenesis and molecular dynamics simulations, we show that the FA anion is first attracted by positively charged arginines or lysines on the matrix side of ANT1 before moving along the positively charged protein-lipid interface and binding to R79, where it is protonated. We show that R79 is also critical for the competitive binding of ANT1 substrates (ADP and ATP) and inhibitors (carboxyatractyloside and bongkrekic acid). The binding sites are well conserved in mitochondrial SLC25 members, suggesting a general mechanism for transporting FA anions across the inner mitochondrial membrane.
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Affiliation(s)
- Jürgen Kreiter
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
| | - Sanja Škulj
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, 10000 Zagreb, Croatia;
| | - Sarah Bardakji
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
| | - Mario Vazdar
- Department of Mathematics, Informatics, and Cybernetics, University of Chemistry and Technology, 166 28 Prague, Czech Republic
| | - Elena E. Pohl
- Institute of Physiology, Pathophysiology, and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (S.Š.); (S.B.)
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7
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Bailoni E, Partipilo M, Coenradij J, Grundel DAJ, Slotboom DJ, Poolman B. Minimal Out-of-Equilibrium Metabolism for Synthetic Cells: A Membrane Perspective. ACS Synth Biol 2023; 12:922-946. [PMID: 37027340 PMCID: PMC10127287 DOI: 10.1021/acssynbio.3c00062] [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: 01/30/2023] [Indexed: 04/08/2023]
Abstract
Life-like systems need to maintain a basal metabolism, which includes importing a variety of building blocks required for macromolecule synthesis, exporting dead-end products, and recycling cofactors and metabolic intermediates, while maintaining steady internal physical and chemical conditions (physicochemical homeostasis). A compartment, such as a unilamellar vesicle, functionalized with membrane-embedded transport proteins and metabolic enzymes encapsulated in the lumen meets these requirements. Here, we identify four modules designed for a minimal metabolism in a synthetic cell with a lipid bilayer boundary: energy provision and conversion, physicochemical homeostasis, metabolite transport, and membrane expansion. We review design strategies that can be used to fulfill these functions with a focus on the lipid and membrane protein composition of a cell. We compare our bottom-up design with the equivalent essential modules of JCVI-syn3a, a top-down genome-minimized living cell with a size comparable to that of large unilamellar vesicles. Finally, we discuss the bottlenecks related to the insertion of a complex mixture of membrane proteins into lipid bilayers and provide a semiquantitative estimate of the relative surface area and lipid-to-protein mass ratios (i.e., the minimal number of membrane proteins) that are required for the construction of a synthetic cell.
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Affiliation(s)
- Eleonora Bailoni
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Michele Partipilo
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Jelmer Coenradij
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Douwe A. J. Grundel
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Dirk J. Slotboom
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
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8
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Rolver MG, Holland LKK, Ponniah M, Prasad NS, Yao J, Schnipper J, Kramer S, Elingaard-Larsen L, Pedraz-Cuesta E, Liu B, Pardo LA, Maeda K, Sandelin A, Pedersen SF. Chronic acidosis rewires cancer cell metabolism through PPARα signaling. Int J Cancer 2023; 152:1668-1684. [PMID: 36533672 PMCID: PMC10108231 DOI: 10.1002/ijc.34404] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/25/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022]
Abstract
The mechanisms linking tumor microenvironment acidosis to disease progression are not understood. Here, we used mammary, pancreatic, and colon cancer cells to show that adaptation to growth at an extracellular pH (pHe ) mimicking acidic tumor niches is associated with upregulated net acid extrusion capacity and elevated intracellular pH at physiological pHe , but not at acidic pHe . Using metabolic profiling, shotgun lipidomics, imaging and biochemical analyses, we show that the acid adaptation-induced phenotype is characterized by a shift toward oxidative metabolism, increased lipid droplet-, triacylglycerol-, peroxisome content and mitochondrial hyperfusion. Peroxisome proliferator-activated receptor-α (PPARA, PPARα) expression and activity are upregulated, at least in part by increased fatty acid uptake. PPARα upregulates genes driving increased mitochondrial and peroxisomal mass and β-oxidation capacity, including mitochondrial lipid import proteins CPT1A, CPT2 and SLC25A20, electron transport chain components, peroxisomal proteins PEX11A and ACOX1, and thioredoxin-interacting protein (TXNIP), a negative regulator of glycolysis. This endows acid-adapted cancer cells with increased capacity for utilizing fatty acids for metabolic needs, while limiting glycolysis. As a consequence, the acid-adapted cells exhibit increased sensitivity to PPARα inhibition. We conclude that PPARα is a key upstream regulator of metabolic changes favoring cancer cell survival in acidic tumor niches.
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Affiliation(s)
- Michala G Rolver
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lya K K Holland
- Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Muthulakshmi Ponniah
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nanditha S Prasad
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jiayi Yao
- The Bioinformatics Center, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Biotech Research and Innovation Center, University of Copenhagen, Copenhagen, Denmark
| | - Julie Schnipper
- Laboratory of Cellular and Molecular Physiology, University of Picardie Jules Verne, Amiens, France
| | - Signe Kramer
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Elena Pedraz-Cuesta
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Bin Liu
- Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Luis A Pardo
- Oncophysiology Group, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Kenji Maeda
- Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Albin Sandelin
- The Bioinformatics Center, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Biotech Research and Innovation Center, University of Copenhagen, Copenhagen, Denmark
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Rahman MK, Umashankar B, Choucair H, Pazderka C, Bourget K, Chen Y, Dunstan CR, Rawling T, Murray M. Inclusion of the in-chain sulfur in 3-thiaCTU increases the efficiency of mitochondrial targeting and cell killing by anticancer aryl-urea fatty acids. Eur J Pharmacol 2023; 939:175470. [PMID: 36543287 DOI: 10.1016/j.ejphar.2022.175470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Mitochondria in tumor cells are functionally different from those in normal cells and could be targeted to develop new anticancer agents. We showed recently that the aryl-ureido fatty acid CTU is the prototype of a new class of mitochondrion-targeted agents that kill cancer cells by increasing the production of reactive oxygen species (ROS), activating endoplasmic reticulum (ER)-stress and promoting apoptosis. However, prolonged treatment with high doses of CTU were required for in vivo anti-tumor activity. Thus, new strategies are now required to produce agents that have enhanced anticancer activity over CTU. In the present study we prepared a novel aryl-urea termed 3-thiaCTU, that contained an in-chain sulfur heteroatom, for evaluation in tumor cell lines and in mice carrying tumor xenografts. The principal finding to emerge was that 3-thiaCTU was several-fold more active than CTU in the activation of aryl-urea mechanisms that promoted cancer cell killing. Thus, in in vitro studies 3-thiaCTU disrupted the mitochondrial membrane potential, increased ROS production, activated ER-stress and promoted tumor cell apoptosis more effectively than CTU. 3-ThiaCTU was also significantly more active than CTUin vivo in mice that carried MDA-MB-231 cell xenografts. Compared to CTU, 3-thiaCTU prevented tumor growth more effectively and at much lower doses. These findings indicate that, in comparison to CTU, 3-thiaCTU is an aryl-urea with markedly enhanced activity that could now be suitable for development as a novel anticancer agent.
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Affiliation(s)
- Md Khalilur Rahman
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, and School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, 2006, Australia
| | - Balasubrahmanyam Umashankar
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, and School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, 2006, Australia
| | - Hassan Choucair
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, and School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, 2006, Australia
| | - Curtis Pazderka
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales, 2007, Australia
| | - Kirsi Bourget
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, and School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, 2006, Australia
| | - Yongjuan Chen
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, and School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, 2006, Australia; Biomaterials and Tissue Engineering Research Unit, School of Biomedical Engineering, University of Sydney, New South Wales, 2006, Australia
| | - Colin R Dunstan
- Biomaterials and Tissue Engineering Research Unit, School of Biomedical Engineering, University of Sydney, New South Wales, 2006, Australia
| | - Tristan Rawling
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales, 2007, Australia
| | - Michael Murray
- Pharmacogenomics and Drug Development Group, Discipline of Pharmacology, School of Medical Sciences, and School of Pharmacy, Faculty of Medicine and Health, University of Sydney, New South Wales, 2006, Australia.
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10
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Chiba O, Shimada N, Yoshio S, Kudo Y, Cho Y, Yotsu-Yamashita M, Konoki K. State-Dependent Inhibition of Voltage-Gated Sodium Channels in Neuroblastoma Neuro-2A Cells by Arachidonic Acid from Halichondria okadai. Chem Res Toxicol 2022; 35:1950-1961. [PMID: 36315108 DOI: 10.1021/acs.chemrestox.2c00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Voltage-gated sodium channels (Nav) are closely associated with epilepsy, cardiac and skeletal muscle diseases, and neuropathic pain. Several toxic compounds have been isolated from the marine sponge Halichondria okadai; however, toxic substances that modulate Nav are yet to be identified. This study aimed to identify Nav inhibitors from two snake venoms and H. okadai using mouse neuroblastoma Neuro-2A cells (N2A), which primarily express the specific Nav subtype Nav1.7, using whole-cell patch-clamp recordings. We successfully isolated arachidonic acid (AA, 1) from the hexane extract of H. okadai, and then the fatty acid-mediated modulation of Nav in N2A was investigated in detail for the first time. Octanoic acid (2), palmitic acid (3), and oleic acid (4) showed no inhibitory activity at 100 μM, whereas AA (1), dihomo-γ-linolenic acid (DGLA, 5), and eicosapentaenoic acid (EPA, 6) showed IC50 values of 6.1 ± 2.0, 58 ± 19, and 25 ± 4.0 μM, respectively (N = 4, mean ± SEM). Structure and activity relationships were investigated for the first time using two ω-3 polyunsaturated fatty acids (PUFAs), EPA (6) and eicosatetraenoic acid (ETA, 7), and two ω-6 PUFAs, AA (1) and DGLA (5), to determine their effects on a resting state, activated state, and inactivated state. Steady-state analysis showed that the half inactivation potential was largely hyperpolarized by 10 μM AA (1), while 50 μM DGLA (5), 50 μM EPA (6), and 10 μM ETA (7) led to a slight change. The percentages of the resting state block were 24 ± 1, 22 ± 1, 34 ± 4, and 38 ± 9% in the presence of AA (1), DGLA (5), EPA (6), and ETA (7), respectively, with EPA (6) and ETA (7) exhibiting a greater inhibition than both AA (1) and DGLA (5), and their inhibitions did not increase in the following depolarization pulses. None of the compounds exhibited the use-dependent block. The half recovery times from the inactivated state for the control, AA (1), DGLA (5), EPA (6), and ETA (7) were 7.67 ± 0.33, 34.3 ± 1.10, 15.5 ± 1.10, 10.7 ± 0.31, and 3.59 ± 0.18 ms, respectively, with AA (1) exhibiting a distinctively large effect. Overall, distributed binding to the resting and the inactivated states of Nav would be significant for the inhibition of Nav, which presumably depends on the active structure of each PUFA.
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Affiliation(s)
- Osamu Chiba
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Noriko Shimada
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Shutaro Yoshio
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Yuta Kudo
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Yuko Cho
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Mari Yotsu-Yamashita
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
| | - Keiichi Konoki
- Graduate School of Agricultural Science, Tohoku University, 468-1 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8572, Japan
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11
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Hybrid bilayer membranes as platforms for biomimicry and catalysis. Nat Rev Chem 2022; 6:862-880. [PMID: 37117701 DOI: 10.1038/s41570-022-00433-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2022] [Indexed: 11/08/2022]
Abstract
Hybrid bilayer membrane (HBM) platforms represent an emerging nanoscale bio-inspired interface that has broad implications in energy catalysis and smart molecular devices. An HBM contains multiple modular components that include an underlying inorganic surface with a biological layer appended on top. The inorganic interface serves as a support with robust mechanical properties that can also be decorated with functional moieties, sensing units and catalytic active sites. The biological layer contains lipids and membrane-bound entities that facilitate or alter the activity and selectivity of the embedded functional motifs. With their structural complexity and functional flexibility, HBMs have been demonstrated to enhance catalytic turnover frequency and regulate product selectivity of the O2 and CO2 reduction reactions, which have applications in fuel cells and electrolysers. HBMs can also steer the mechanistic pathways of proton-coupled electron transfer (PCET) reactions of quinones and metal complexes by tuning electron and proton delivery rates. Beyond energy catalysis, HBMs have been equipped with enzyme mimics and membrane-bound redox agents to recapitulate natural energy transport chains. With channels and carriers incorporated, HBM sensors can quantify transmembrane events. This Review serves to summarize the major accomplishments achieved using HBMs in the past decade.
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12
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Shen J, Ye R, Liu Z, Zeng H. Hybrid Pyridine–Pyridone Foldamer Channels as M2‐Like Artificial Proton Channels. Angew Chem Int Ed Engl 2022; 61:e202200259. [DOI: 10.1002/anie.202200259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Jie Shen
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Ruijuan Ye
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Zhiwei Liu
- Department of Chemistry & Biochemistry Rowan University 201 Mullica Hill Road Glassboro NJ 08028 USA
| | - Huaqiang Zeng
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
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13
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Shen J, Ye R, Liu Z, Zeng H. Hybrid Pyridine–Pyridone Foldamer Channels as M2‐Like Artificial Proton Channels. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jie Shen
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Ruijuan Ye
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
| | - Zhiwei Liu
- Department of Chemistry & Biochemistry Rowan University 201 Mullica Hill Road Glassboro NJ 08028 USA
| | - Huaqiang Zeng
- College of Chemistry Fuzhou University Fuzhou Fujian 350116 China
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14
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Assies L, Mercier V, López-Andarias J, Roux A, Sakai N, Matile S. The Dynamic Range of Acidity: Tracking Rules for the Unidirectional Penetration of Cellular Compartments. Chembiochem 2022; 23:e202200192. [PMID: 35535626 PMCID: PMC9400975 DOI: 10.1002/cbic.202200192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/09/2022] [Indexed: 12/03/2022]
Abstract
Labeled ammonium cations with pKa∼7.4 accumulate in acidic organelles because they can be neutralized transiently to cross the membrane at cytosolic pH 7.2 but not at their internal pH<5.5. Retention in early endosomes with less acidic internal pH was achieved recently using weaker acids of up to pKa 9.8. We report here that primary ammonium cations with higher pKa 10.6, label early endosomes more efficiently. This maximized early endosome tracking coincides with increasing labeling of Golgi networks with similarly weak internal acidity. Guanidinium cations with pKa 13.5 cannot cross the plasma membrane in monomeric form and label the plasma membrane with selectivity for vesicles embarking into endocytosis. Self‐assembled into micelles, guanidinium cations enter cells like arginine‐rich cell‐penetrating peptides and, driven by their membrane potential, penetrate mitochondria unidirectionally despite their high inner pH. The resulting tracking rules with an approximated dynamic range of pKa change ∼3.5 are expected to be generally valid, thus enabling the design of chemistry tools for biology research in the broadest sense. From a practical point of view, most relevant are two complementary fluorescent flipper probes that can be used to image the mechanics at the very beginning of endocytosis.
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Affiliation(s)
- Lea Assies
- University of Geneva Faculty of Science: Universite de Geneve Faculte des Sciences, School of Chemistry and Biochemistry, SWITZERLAND
| | - Vincent Mercier
- University of Geneva Faculty of Science: Universite de Geneve Faculte des Sciences, School of Chemistry and Biochemistry, SWITZERLAND
| | - Javier López-Andarias
- University of Geneva Faculty of Science: Universite de Geneve Faculte des Sciences, School of Chemistry and Biochemistry, SWITZERLAND
| | - Aurelien Roux
- University of Geneva Faculty of Science: Universite de Geneve Faculte des Sciences, School of Chemistry and Biochemistry, SWITZERLAND
| | - Naomi Sakai
- University of Geneva Faculty of Science: Universite de Geneve Faculte des Sciences, School of Chemistry and Biochemistry, SWITZERLAND
| | - Stefan Matile
- University of Geneva, Department of Organic Chemistry, Quai Ernest-Ansermet 30, CH-1211, Geneva, SWITZERLAND
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15
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Chen L, Wu X, Gilchrist AM, Gale PA. Organoplatinum Compounds as Anion‐Tuneable Uphill Hydroxide Transporters. Angew Chem Int Ed Engl 2022; 61:e202116355. [PMID: 35192743 PMCID: PMC9310596 DOI: 10.1002/anie.202116355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Indexed: 11/12/2022]
Abstract
Active transport of ions uphill, creating a concentration gradient across a cell membrane, is essential for life. It remains a significant challenge to develop synthetic systems that allow active uphill transport. Here, a transport process fuelled by organometallic compounds is reported that creates a pH gradient. The hydrolysis reaction of PtII complexes results in the formation of aqua complexes that established rapid transmembrane movement (“flip‐flop”) of neutral Pt−OH species, leading to protonation of the OH group in the inner leaflet, generating OH− ions, and so increasing the pH in the intravesicular solution. The organoplatinum complex effectively transports bound hydroxide ions across the membrane in a neutral complex. The initial net flow of the PtII complex into the vesicles generates a positive electric potential that can further drive uphill transport because the electric potential is opposed to the chemical potential of OH−. The OH− ions equilibrate with this transmembrane electric potential but cannot remove it due to the relatively low permeability of the charged species. As a result, effective hydroxide transport against its concentration gradient can be achieved, and multiple additions can continuously drive the generation of OH− against its concentration gradient up to ΔpH>2. Moreover, the external addition of different anions can control the generation of OH− depending on their anion binding affinity. When anions displayed very high binding affinities towards PtII compounds, such as halides, the external anions could dissipate the pH gradient. In contrast, a further pH increase was observed for weak binding anions, such as sulfate, due to the increase of positive electric potential.
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Affiliation(s)
- Li‐Jun Chen
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
| | - Xin Wu
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
| | | | - Philip A. Gale
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
- The University of Sydney Nano Institute (SydneyNano) The University of Sydney Sydney NSW 2006 Australia
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16
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Li F, Hu G, Long X, Cao Y, Li Q, Guo W, Wang J, Liu J, Fu S. Stearic Acid Activates the PI3K-mTOR-4EBP1/S6K and mTOR-SREBP-1 Signaling Axes through FATP4-CDK1 To Promote Milk Synthesis in Primary Bovine Mammary Epithelial Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:4007-4018. [PMID: 35333520 DOI: 10.1021/acs.jafc.2c00208] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Stearic acid (SA), an 18-carbon long-chain saturated fatty acid, has great potential for promoting lactation. Therefore, this study investigates the effects and mechanism of SA on milk synthesis in primary bovine mammary epithelial cells (BMECs). In our study, we found that SA significantly increased β-casein and triglycerides, and the effect was most significant at 100 μM. Signaling pathway studies have found that SA affects milk synthesis by upregulating cyclin-dependent kinase 1 (CDK1) to activate PI3K-mTOR-4EBP1/S6K and mTOR-SREBP-1 pathways. Furthermore, we detected fatty acid transport proteins (FATPs) when BMECs were treated with SA; the mRNA levels of FATP3 (3.713 ± 0.583) and FATP4 (40.815 ± 8.959) were significantly upregulated at 100 μM. Subsequently, we constructed FATP4-siRNA and found that SA was transported by FATP4 into BMECs, promoting milk synthesis. Collectively, these results revealed that SA activated PI3K-mTOR-4EBP1/S6K and mTOR-SREBP-1 signaling axes through FATP4-CDK1 to promote milk synthesis in BMECs.
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Affiliation(s)
- Feng Li
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Guiqiu Hu
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xiaoyu Long
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Yu Cao
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Qianqian Li
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Wenjin Guo
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Jiaxin Wang
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Juxiong Liu
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Shoupeng Fu
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
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17
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Chen L, Wu X, Gilchrist AM, Gale PA. Organoplatinum Compounds as Anion‐Tuneable Uphill Hydroxide Transporters. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Li‐Jun Chen
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
| | - Xin Wu
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
| | | | - Philip A. Gale
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
- The University of Sydney Nano Institute (SydneyNano) The University of Sydney Sydney NSW 2006 Australia
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18
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Kneiszl R, Hossain S, Larsson P. In Silico-Based Experiments on Mechanistic Interactions between Several Intestinal Permeation Enhancers with a Lipid Bilayer Model. Mol Pharm 2022; 19:124-137. [PMID: 34913341 PMCID: PMC8728740 DOI: 10.1021/acs.molpharmaceut.1c00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 01/07/2023]
Abstract
Oral administration of drugs is generally considered convenient and patient-friendly. However, oral administration of biological drugs exhibits low oral bioavailability (BA) due to enzymatic degradation and low intestinal absorption. A possible approach to circumvent the low BA of oral peptide drugs is to coformulate the drugs with permeation enhancers (PEs). PEs have been studied since the 1960s and are molecules that enhance the absorption of hydrophilic molecules with low permeability over the gastrointestinal epithelium. In this study, we investigated the impact of six PEs on the structural properties of a model membrane using molecular dynamics (MD) simulations. The PEs included were the sodium salts of the medium chain fatty acids laurate, caprate, and caprylate and the caprylate derivative SNAC─all with a negative charge─and neutral caprate and neutral sucrose monolaurate. Our results indicated that the PEs, once incorporated into the membrane, could induce membrane leakiness in a concentration-dependent manner. Our simulations suggest that a PE concentration of at least 70-100 mM is needed to strongly affect transcellular permeability. The increased aggregation propensity seen for neutral PEs might provide a molecular-level mechanism for the membrane disruptions seen at higher concentrations in vivo. The ability for neutral PEs to flip-flop across the lipid bilayer is also suggestive of possible intracellular modes of action other than increasing membrane fluidity. Taken together, our results indicate that MD simulations are useful for gaining insights relevant to the design of oral dosage forms based around permeability enhancer molecules.
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Affiliation(s)
- Rosita Kneiszl
- Department
of Pharmacy, Uppsala University, Husargatan 3, Uppsala 751 23, Sweden
- The
Swedish Drug Delivery Center (SweDeliver), Uppsala University, Husargatan 3, Uppsala 751 23, Sweden
| | - Shakhawath Hossain
- Department
of Pharmacy, Uppsala University, Husargatan 3, Uppsala 751 23, Sweden
- The
Swedish Drug Delivery Center (SweDeliver), Uppsala University, Husargatan 3, Uppsala 751 23, Sweden
| | - Per Larsson
- Department
of Pharmacy, Uppsala University, Husargatan 3, Uppsala 751 23, Sweden
- The
Swedish Drug Delivery Center (SweDeliver), Uppsala University, Husargatan 3, Uppsala 751 23, Sweden
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19
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Kotova EA, Antonenko YN. Fifty Years of Research on Protonophores: Mitochondrial Uncoupling As a Basis for Therapeutic Action. Acta Naturae 2022; 14:4-13. [PMID: 35441048 PMCID: PMC9013436 DOI: 10.32607/actanaturae.11610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/21/2021] [Indexed: 11/20/2022] Open
Abstract
Protonophores are compounds capable of electrogenic transport of protons across
membranes. Protonophores have been intensively studied over the past 50 years
owing to their ability to uncouple oxidation and phosphorylation in
mitochondria and chloroplasts. The action mechanism of classical uncouplers,
such as DNP and CCCP, in mitochondria is believed to be related to their
protonophoric activity; i.e., their ability to transfer protons across the
lipid part of the mitochondrial membrane. Given the recently revealed
deviations in the correlation between the protonophoric activity of some
uncouplers and their ability to stimulate mitochondrial respiration, this
review addresses the involvement of some proteins of the inner mitochondrial
membrane, such as the ATP/ADP antiporter, dicarboxylate carrier, and ATPase, in
the uncoupling process. However, these deviations do not contradict the
Mitchell theory but point to a more complex nature of the interaction of DNP,
CCCP, and other uncouplers with mitochondrial membranes. Therefore, a detailed
investigation of the action mechanism of uncouplers is required for a more
successful pharmacological use, including their antibacterial, antiviral,
anticancer, as well as cardio-, neuro-, and nephroprotective effects.
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Affiliation(s)
- E. A. Kotova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russia
| | - Y. N. Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russia
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20
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Yang J, Yu G, Sessler JL, Shin I, Gale PA, Huang F. Artificial transmembrane ion transporters as potential therapeutics. Chem 2021. [DOI: 10.1016/j.chempr.2021.10.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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21
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Carrer A, Laquatra C, Tommasin L, Carraro M. Modulation and Pharmacology of the Mitochondrial Permeability Transition: A Journey from F-ATP Synthase to ANT. Molecules 2021; 26:molecules26216463. [PMID: 34770872 PMCID: PMC8587538 DOI: 10.3390/molecules26216463] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 12/22/2022] Open
Abstract
The permeability transition (PT) is an increased permeation of the inner mitochondrial membrane due to the opening of the PT pore (PTP), a Ca2+-activated high conductance channel involved in Ca2+ homeostasis and cell death. Alterations of the PTP have been associated with many pathological conditions and its targeting represents an incessant challenge in the field. Although the modulation of the PTP has been extensively explored, the lack of a clear picture of its molecular nature increases the degree of complexity for any target-based approach. Recent advances suggest the existence of at least two mitochondrial permeability pathways mediated by the F-ATP synthase and the ANT, although the exact molecular mechanism leading to channel formation remains elusive for both. A full comprehension of this to-pore conversion will help to assist in drug design and to develop pharmacological treatments for a fine-tuned PT regulation. Here, we will focus on regulatory mechanisms that impinge on the PTP and discuss the relevant literature of PTP targeting compounds with particular attention to F-ATP synthase and ANT.
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22
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Liang N, Hennebelle M, Gaul S, Johnson CD, Zhang Z, Kirpich IA, McClain CJ, Feldstein AE, Ramsden CE, Taha AY. Feeding mice a diet high in oxidized linoleic acid metabolites does not alter liver oxylipin concentrations. Prostaglandins Leukot Essent Fatty Acids 2021; 172:102316. [PMID: 34403987 PMCID: PMC9157566 DOI: 10.1016/j.plefa.2021.102316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/11/2021] [Accepted: 06/17/2021] [Indexed: 11/19/2022]
Abstract
The oxidation of dietary linoleic acid (LA) produces oxidized LA metabolites (OXLAMs) known to regulate multiple signaling pathways in vivo. Recently, we reported that feeding OXLAMs to mice resulted in liver inflammation and apoptosis. However, it is not known whether this is due to a direct effect of OXLAMs accumulating in the liver, or to their degradation into bioactive shorter chain molecules (e.g. aldehydes) that can provoke inflammation and related cascades. To address this question, mice were fed a low or high LA diet low in OXLAMs, or a low LA diet supplemented with OXLAMs from heated corn oil (high OXLAM diet). Unesterified oxidized fatty acids (i.e. oxylipins), including OXLAMs, were measured in liver after 8 weeks of dietary intervention using ultra-high pressure liquid chromatography coupled to tandem mass-spectrometry. The high OXLAM diet did not alter liver oxylipin concentrations compared to the low LA diet low in OXLAMs. Significant increases in several omega-6 derived oxylipins and reductions in omega-3 derived oxylipins were observed in the high LA dietary group compared to the low LA group. Our findings suggest that dietary OXLAMs do not accumulate in liver, and likely exert pro-inflammatory and pro-apoptotic effects via downstream secondary metabolites.
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Affiliation(s)
- Nuanyi Liang
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States
| | - Marie Hennebelle
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States
| | - Susanne Gaul
- Department of Pediatrics, University of California San Diego, La Jolla, CA, Unites States; Klinik und Poliklinik für Kardiologie, University Hospital Leipzig, Leipzig University, Germany
| | - Casey D Johnson
- Department of Pediatrics, University of California San Diego, La Jolla, CA, Unites States
| | - Zhichao Zhang
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States
| | - Irina A Kirpich
- Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville, Louisville, KY; Hepatobiology and Toxicology Program, University of Louisville, Louisville, KY; Department of Pharmacology and Toxicology and University of Louisville Alcohol Center
| | - Craig J McClain
- Division of Gastroenterology, Hepatology, and Nutrition, University of Louisville, Louisville, KY; Hepatobiology and Toxicology Program, University of Louisville, Louisville, KY; Department of Pharmacology and Toxicology and University of Louisville Alcohol Center; Veterans Affairs San Diego Healthcare System, San Diego, CA; and Robley Rex Veterans Medical Center, Louisville, KY
| | - Ariel E Feldstein
- Department of Pediatrics, University of California San Diego, La Jolla, CA, Unites States
| | - Christopher E Ramsden
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, Unites States; National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Ameer Y Taha
- Department of Food Science and Technology, College of Agriculture and Environmental Sciences, University of California Davis, Davis, CA, Unites States.
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23
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Affiliation(s)
- Patrick Wang
- School of Chemistry, The University of Sydney, NSW, Australia
| | - Xin Wu
- School of Chemistry, The University of Sydney, NSW, Australia
| | - Philip A. Gale
- School of Chemistry, The University of Sydney, NSW, Australia
- The University of Sydney Nano Institute (SydneyNano), The University of Sydney, NSW, Australia
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24
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Toparlak Ö, Wang A, Mansy SS. Population-Level Membrane Diversity Triggers Growth and Division of Protocells. JACS AU 2021; 1:560-568. [PMID: 34467319 PMCID: PMC8395648 DOI: 10.1021/jacsau.0c00079] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Indexed: 06/01/2023]
Abstract
To date, multiple mechanisms have been described for the growth and division of model protocells, all of which exploit the lipid dynamics of fatty acids. In some examples, the more heterogeneous aggregate consisting of fatty acid and diacyl phospholipid or fatty acid and peptide grows at the expense of the more homogeneous aggregate containing a restricted set of lipids with similar dynamics. Imbalances between surface area and volume during growth can generate filamentous vesicles, which are typically divided by shear forces. Here, we describe another pathway for growth and division that depends simply on differences in the compositions of fatty acid membranes without additional components. Growth is driven by the thermodynamically favorable mixing of lipids between two populations, i.e., the system as a whole proceeds toward equilibrium. Division is the result of growth-induced curvature. Importantly, growth and division do not require a specific composition of lipids. For example, vesicles made from one type of lipid, e.g., short-chain fatty acids, grow and divide when fed with vesicles consisting of another type of lipid, e.g., long-chain fatty acids, and vice versa. After equilibration, additional rounds of growth and division could potentially proceed by the introduction of compositionally distinct aggregates. Since prebiotic synthesis likely gave rise to mixtures of lipids, the data are consistent with the presence of growing and dividing protocells on the prebiotic Earth.
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Affiliation(s)
- Ö.
Duhan Toparlak
- Department
of Cellular, Computational and Integrative Biology (D-CIBIO), University of Trento, Via Sommarive 9, 38123 Povo, TN, Italy
| | - Anna Wang
- School
of Chemistry and Australian Centre for Astrobiology, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Sheref S. Mansy
- Department
of Cellular, Computational and Integrative Biology (D-CIBIO), University of Trento, Via Sommarive 9, 38123 Povo, TN, Italy
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G
2G2, Canada
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25
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Holló G, Miele Y, Rossi F, Lagzi I. Shape changes and budding of giant vesicles induced by an internal chemical trigger: an interplay between osmosis and pH change. Phys Chem Chem Phys 2021; 23:4262-4270. [PMID: 33587060 DOI: 10.1039/d0cp05952h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Shape transformation and budding of phospholipid/fatty acid giant hybrid vesicles can be induced by an internal chemical stimulus (pH change) when coupled with an osmotic shock. In particular, an autocatalytic enzymatic reaction set (urea-urease system), confined in the lumen of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/oleic acid (HOA) vesicles, can force the budding of the hosting vesicle, when properly fed by a trans-membrane substrate infusion. Herein, we elucidate the budding mechanism by simulating the shape changes of a vesicle during the enzymatic reaction. The area-difference-elasticity (ADE) theory is thus implemented to minimize the surface elastic energy and obtain the equilibrium shape at different values of the reduced volume and different values of the reduced preferred area difference (Δa0). Simulations, together with control experiments, unambiguously show that to obtain an effective vesicle shape transformation, the osmotic stress and the pH change in the lumen of the vesicle must act in synergy at the same timescale. Osmotic pressure induces a vesicle deflation (volume loss), while the pH change affects the preferred area difference between the outer and the inner membrane leaflets.
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Affiliation(s)
- Gábor Holló
- MTA-BME Condensed Matter Physics Research Group, Budapest University of Technology and Economics 1111, Budafoki ut 8, Budapest, Hungary
| | - Ylenia Miele
- Department of Chemistry and Biology "A. Zambelli"University of Salerno, Via Giovanni Paolo II 132, 84084 - Fisciano (SA), Italy
| | - Federico Rossi
- Department of Earth, Environmental and Physical Sciences - DEEP Sciences, University of Siena, Pian dei Mantellini 44, 53100 - Siena, Italy.
| | - István Lagzi
- Department of Physics, Budapest University of Technology and Economics 1111, Budafoki út 8, Budapest, Hungary.
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26
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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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Kreiter J, Rupprecht A, Škulj S, Brkljača Z, Žuna K, Knyazev DG, Bardakji S, Vazdar M, Pohl EE. ANT1 Activation and Inhibition Patterns Support the Fatty Acid Cycling Mechanism for Proton Transport. Int J Mol Sci 2021; 22:ijms22052490. [PMID: 33801254 PMCID: PMC7958136 DOI: 10.3390/ijms22052490] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 01/26/2023] Open
Abstract
Adenine nucleotide translocase (ANT) is a well-known mitochondrial exchanger of ATP against ADP. In contrast, few studies have shown that ANT also mediates proton transport across the inner mitochondrial membrane. The results of these studies are controversial and lead to different hypotheses about molecular transport mechanisms. We hypothesized that the H+-transport mediated by ANT and uncoupling proteins (UCP) has a similar regulation pattern and can be explained by the fatty acid cycling concept. The reconstitution of purified recombinant ANT1 in the planar lipid bilayers allowed us to measure the membrane current after the direct application of transmembrane potential ΔΨ, which would correspond to the mitochondrial states III and IV. Experimental results reveal that ANT1 does not contribute to a basal proton leak. Instead, it mediates H+ transport only in the presence of long-chain fatty acids (FA), as already known for UCPs. It depends on FA chain length and saturation, implying that FA’s transport is confined to the lipid-protein interface. Purine nucleotides with the preference for ATP and ADP inhibited H+ transport. Specific inhibitors of ATP/ADP transport, carboxyatractyloside or bongkrekic acid, also decreased proton transport. The H+ turnover number was calculated based on ANT1 concentration determined by fluorescence correlation spectroscopy and is equal to 14.6 ± 2.5 s−1. Molecular dynamic simulations revealed a large positively charged area at the protein/lipid interface that might facilitate FA anion’s transport across the membrane. ANT’s dual function—ADP/ATP and H+ transport in the presence of FA—may be important for the regulation of mitochondrial membrane potential and thus for potential-dependent processes in mitochondria. Moreover, the expansion of proton-transport modulating drug targets to ANT1 may improve the therapy of obesity, cancer, steatosis, cardiovascular and neurodegenerative diseases.
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Affiliation(s)
- Jürgen Kreiter
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (A.R.); (K.Ž.); (S.B.)
| | - Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (A.R.); (K.Ž.); (S.B.)
- Institute of Pharmacology and Toxicology, Rostock University Medical Center, 18057 Rostock, Germany
| | - Sanja Škulj
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute,10000 Zagreb, Croatia; (S.Š.); (Z.B.); (M.V.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute,10000 Zagreb, Croatia; (S.Š.); (Z.B.); (M.V.)
| | - Kristina Žuna
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (A.R.); (K.Ž.); (S.B.)
| | - Denis G. Knyazev
- Institute of Biophysics, Johannes Kepler University, 4020 Linz, Austria;
| | - Sarah Bardakji
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (A.R.); (K.Ž.); (S.B.)
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute,10000 Zagreb, Croatia; (S.Š.); (Z.B.); (M.V.)
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague 6, Czech Republic
| | - Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria; (J.K.); (A.R.); (K.Ž.); (S.B.)
- Correspondence:
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28
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Škulj S, Brkljača Z, Kreiter J, Pohl EE, Vazdar M. Molecular Dynamics Simulations of Mitochondrial Uncoupling Protein 2. Int J Mol Sci 2021; 22:ijms22031214. [PMID: 33530558 PMCID: PMC7866055 DOI: 10.3390/ijms22031214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 11/16/2022] Open
Abstract
Molecular dynamics (MD) simulations of uncoupling proteins (UCP), a class of transmembrane proteins relevant for proton transport across inner mitochondrial membranes, represent a complicated task due to the lack of available structural data. In this work, we use a combination of homology modelling and subsequent microsecond molecular dynamics simulations of UCP2 in the DOPC phospholipid bilayer, starting from the structure of the mitochondrial ATP/ADP carrier (ANT) as a template. We show that this protocol leads to a structure that is impermeable to water, in contrast to MD simulations of UCP2 structures based on the experimental NMR structure. We also show that ATP binding in the UCP2 cavity is tight in the homology modelled structure of UCP2 in agreement with experimental observations. Finally, we corroborate our results with conductance measurements in model membranes, which further suggest that the UCP2 structure modeled from ANT protein possesses additional key functional elements, such as a fatty acid-binding site at the R60 region of the protein, directly related to the proton transport mechanism across inner mitochondrial membranes.
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Affiliation(s)
- Sanja Škulj
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
| | - Jürgen Kreiter
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, 1210 Vienna, Austria;
| | - Elena E. Pohl
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, 1210 Vienna, Austria;
- Correspondence: (E.E.P.); (M.V.)
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague, Czech Republic
- Correspondence: (E.E.P.); (M.V.)
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29
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Grünewald F, Souza PCT, Abdizadeh H, Barnoud J, de Vries AH, Marrink SJ. Titratable Martini model for constant pH simulations. J Chem Phys 2020; 153:024118. [PMID: 32668918 DOI: 10.1063/5.0014258] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In this work, we deliver a proof of concept for a fast method that introduces pH effects into classical coarse-grained (CG) molecular dynamics simulations. Our approach is based upon the latest version of the popular Martini CG model to which explicit proton mimicking particles are added. We verify our approach against experimental data involving several different molecules and different environmental conditions. In particular, we compute titration curves, pH dependent free energies of transfer, and lipid bilayer membrane affinities as a function of pH. Using oleic acid as an example compound, we further illustrate that our method can be used to study passive translocation in lipid bilayers via protonation. Finally, our model reproduces qualitatively the expansion of the macromolecule dendrimer poly(propylene imine) as well as the associated pKa shift of its different generations. This example demonstrates that our model is able to pick up collective interactions between titratable sites in large molecules comprising many titratable functional groups.
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Affiliation(s)
- Fabian Grünewald
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Paulo C T Souza
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Haleh Abdizadeh
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Jonathan Barnoud
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Alex H de Vries
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
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30
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Liang N, Dacko A, Tan AK, Xiang S, Curtis JM, Gänzle MG. Structure-function relationships of antifungal monohydroxy unsaturated fatty acids (HUFA) of plant and bacterial origin. Food Res Int 2020; 134:109237. [PMID: 32517955 DOI: 10.1016/j.foodres.2020.109237] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 04/05/2020] [Accepted: 04/09/2020] [Indexed: 12/30/2022]
Abstract
This study investigated the relationships between the structures of hydroxy unsaturated fatty acids (HUFA) and their antifungal activities. Structurally diverse HUFA, including four monohydroxy-18:1 isomers, two monohydroxy 18:2 isomers and two monohydroxy 18:2 isomers were extracted from seeds of plants (Coriaria nepalensis, Thymus vulgaris, Mallotus philippensis and Dimorphotheca sinuata) for which information was available on PlantFAdb database, and from culture supernatants of lactobacilli. They were purified by high-speed counter current chromatography (HSCCC) and identified by LC-MS/MS. The minimum inhibitory concentrations of HUFA were tested against a panel of five yeasts and five mycelial fungi. The membrane phase changes under HUFA treatment and the content of ergosterol were both measured to differentiate HUFA-sensitive and HUFA-resistant fungi. HUFA with a hydroxyl group near the center of the 18-carbon fatty acid chains were found to contribute strongly to HUFA antifungal activity. Antifungal HUFA targeted filamentous fungi but not yeasts. HUFA didn't alter the overall membrane fluidity of sensitive fungi, but the most HUFA-sensitive fungi had a lower average ergosterol content compared to the resistant yeasts. This indicates the possible interaction of HUFA with fungal membrane with low sterol content, which partially support the previous proposed mode of action. Findings here provide insight on further development of HUFA application in food products.
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Affiliation(s)
- Nuanyi Liang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Andrea Dacko
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Alexander K Tan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Sheng Xiang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Jonathan M Curtis
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
| | - Michael G Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
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31
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Pownall HJ. Commentary on SSO and other putative inhibitors of FA transport across membranes by CD36 disrupt intracellular metabolism, but do not affect fatty acid translocation. J Lipid Res 2020; 61:595-597. [PMID: 32198211 DOI: 10.1194/jlr.c120000745] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Henry J Pownall
- Center for Bioenergetics, Houston Methodist Research Institute, Houston, TX 77030. mailto:
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32
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Miele Y, Medveczky Z, Holló G, Tegze B, Derényi I, Hórvölgyi Z, Altamura E, Lagzi I, Rossi F. Self-division of giant vesicles driven by an internal enzymatic reaction. Chem Sci 2020; 11:3228-3235. [PMID: 34122829 PMCID: PMC8157745 DOI: 10.1039/c9sc05195c] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/08/2020] [Indexed: 12/16/2022] Open
Abstract
Self-division is one of the most common phenomena in living systems and one of the most important properties of life driven by internal mechanisms of cells. Design and engineering of synthetic cells from abiotic components can recreate a life-like function thus contributing to the understanding of the origin of life. Existing methods to induce the self-division of vesicles require external and non-autonomous triggers (temperature change and the addition of membrane precursors). Here we show that pH-responsive giant unilamellar vesicles on the micrometer scale can undergo self-division triggered by an internal autonomous chemical stimulus driven by an enzymatic (urea-urease) reaction coupled to a cross-membrane transport of the substrate, urea. The bilayer of the artificial cells is composed of a mixture of phospholipids (POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine) and oleic acid molecules. The enzymatic reaction increases the pH in the lumen of the vesicles, which concomitantly changes the protonation state of the oleic acid in the inner leaflet of the bilayer causing the removal of the membrane building blocks into the lumen of the vesicles thus decreasing the inner membrane area with respect to the outer one. This process coupled to the osmotic stress (responsible for the volume loss of the vesicles) leads to the division of a mother vesicle into two smaller daughter vesicles. These two processes must act in synergy; none of them alone can induce the division. Overall, our self-dividing system represents a step forward in the design and engineering of a complex autonomous model of synthetic cells.
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Affiliation(s)
- Ylenia Miele
- Department of Chemistry and Biology "A. Zambelli", University of Salerno Via Giovanni Paolo II 132, 84084 - Fisciano SA Italy
| | - Zsófia Medveczky
- Department of Physics, Budapest University of Technology and Economics H-1111, Budafoki ut 8 Budapest Hungary
| | - Gábor Holló
- MTA-BME Condensed Matter Research Group, Budapest University of Technology and Economics H-1111, Budafoki út 8 Budapest Hungary
| | - Borbála Tegze
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics H-1111 Budafoki ut 8 Budapest Hungary
| | - Imre Derényi
- Department of Biological Physics, Eötvös Loránd University H-1117 Pázmány Péter sétány 1/A Budapest Hungary
- MTA-ELTE Statistical and Biological Physics Research Group, Eötvös Loránd University H-1117 Pázmány Péter sétány 1/A Budapest Hungary
| | - Zoltán Hórvölgyi
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics H-1111 Budafoki ut 8 Budapest Hungary
| | - Emiliano Altamura
- Department of Chemistry, University of Bari, "Aldo Moro" Via Orabona 4 I-70125 Bari Italy
| | - István Lagzi
- Department of Physics, Budapest University of Technology and Economics H-1111, Budafoki ut 8 Budapest Hungary
- MTA-BME Condensed Matter Research Group, Budapest University of Technology and Economics H-1111, Budafoki út 8 Budapest Hungary
| | - Federico Rossi
- Department of Chemistry and Biology "A. Zambelli", University of Salerno Via Giovanni Paolo II 132, 84084 - Fisciano SA Italy
- Department of Earth, Environmental and Physical Sciences - DEEP Sciences, University of Siena Pian dei Mantellini 44 53100 - Siena Italy
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33
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Jay AG, Simard JR, Huang N, Hamilton JA. SSO and other putative inhibitors of FA transport across membranes by CD36 disrupt intracellular metabolism, but do not affect FA translocation. J Lipid Res 2020; 61:790-807. [PMID: 32102800 DOI: 10.1194/jlr.ra120000648] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/19/2020] [Indexed: 12/19/2022] Open
Abstract
Membrane-bound proteins have been proposed to mediate the transport of long-chain FA (LCFA) transport through the plasma membrane (PM). These proposals are based largely on reports that PM transport of LCFAs can be blocked by a number of enzymes and purported inhibitors of LCFA transport. Here, using the ratiometric pH indicator (2',7'-bis-(2-carboxyethyl)-5-(and-6-)-carboxyfluorescein and acrylodated intestinal FA-binding protein-based dual fluorescence assays, we investigated the effects of nine inhibitors of the putative FA transporter protein CD36 on the binding and transmembrane movement of LCFAs. We particularly focused on sulfosuccinimidyl oleate (SSO), reported to be a competitive inhibitor of CD36-mediated LCFA transport. Using these assays in adipocytes and inhibitor-treated protein-free lipid vesicles, we demonstrate that rapid LCFA transport across model and biological membranes remains unchanged in the presence of these purported inhibitors. We have previously shown in live cells that CD36 does not accelerate the transport of unesterified LCFAs across the PM. Our present experiments indicated disruption of LCFA metabolism inside the cell within minutes upon treatment with many of the "inhibitors" previously assumed to inhibit LCFA transport across the PM. Furthermore, using confocal microscopy and a specific anti-SSO antibody, we found that numerous intracellular and PM-bound proteins are SSO-modified in addition to CD36. Our results support the hypothesis that LCFAs diffuse rapidly across biological membranes and do not require an active protein transporter for their transmembrane movement.
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Affiliation(s)
- Anthony G Jay
- Department of Physiology and Biomedical Engineering,Mayo Clinic, Rochester, MN 55905; Departments of Biochemistry,Boston University School of Medicine, Boston, MA 02118. mailto:
| | - Jeffrey R Simard
- Physiology and Biophysics,Boston University School of Medicine, Boston, MA 02118; Pharmacology and Experimental Therapeutics,Boston University School of Medicine, Boston, MA 02118
| | - Nasi Huang
- Section of Infectious Diseases Department of Medicine,Boston University School of Medicine, Boston, MA 02118
| | - James A Hamilton
- Physiology and Biophysics,Boston University School of Medicine, Boston, MA 02118
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Dalai P, Sahai N. A Model Protometabolic Pathway Across Protocell Membranes Assisted by Photocatalytic Minerals. J Phys Chem B 2019. [PMID: 31869230 DOI: 10.1021/acs.jpcb.9b10127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Protocell analogs (lipid vesicles) to modern cell membranes have been postulated as compartments that may have been involved in primordial metabolism during the transition from geochemistry to biochemistry on early Earth. The transduction of light energy into chemical energy for metabolism was a key step in the transition from the earliest metabolisms to phototrophy. Photocatalytic minerals may have served the role of enzymes during these transitional stages. Here, we demonstrate a simple photoheterotrophic protometabolism promoted by photocatalytic minerals across a model protocell (vesicle) membrane. These minerals in the extra-vesicular medium utilized light energy to drive a coupled, multi-step transmembrane electron transfer reaction (TMETR), while simultaneously generating a transmembrane pH gradient and reducing nicotinamide adenine dinucleotide (NAD+) to NADH within the vesicle. The proton gradient or chemiosmotic potential could have provided a basis for adenosine triphosphate (ATP) synthesis and NADH could potentially have driven further metabolic chemistry inside the protocells.
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35
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Cheng V, Kimball DR, Conboy DJC. Determination of the Rate-Limiting Step in Fatty Acid Transport. J Phys Chem B 2019; 123:7157-7168. [DOI: 10.1021/acs.jpcb.9b05162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Victoria Cheng
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Dylan R. Kimball
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
| | - Dr. John C. Conboy
- Department of Chemistry, University of Utah, 315 South 1400 East, RM 2020, Salt Lake City, Utah 84112, United States
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36
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Howe ENW, Gale PA. Fatty Acid Fueled Transmembrane Chloride Transport. J Am Chem Soc 2019; 141:10654-10660. [DOI: 10.1021/jacs.9b02116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Ethan N. W. Howe
- School of Chemistry, The University of Sydney, Sydney NSW 2006, Australia
| | - Philip A. Gale
- School of Chemistry, The University of Sydney, Sydney NSW 2006, Australia
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37
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Mechanism of Long-Chain Free Fatty Acid Protonation at the Membrane-Water Interface. Biophys J 2019; 114:2142-2151. [PMID: 29742407 DOI: 10.1016/j.bpj.2018.04.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/19/2018] [Accepted: 04/02/2018] [Indexed: 01/06/2023] Open
Abstract
Long-chain free fatty acids (FFAs) play an important role in several physiological and pathological processes such as lipid fusion, adjustments of membrane permeability and fluidity, and the regulation of enzyme and protein activities. FFA-facilitated membrane proton transport (flip-flop) and FFA-dependent proton transport by membrane proteins (e.g., mitochondrial uncoupling proteins) are governed by the difference between FFA's intrinsic pKa value and the pH in the immediate membrane vicinity. Thus far, a quantitative understanding of the process has been hampered, because the pKa value shifts upon moving the FFA from the aqueous solution into the membrane. For the same FFA, pKa values between 5 and 10.5 were reported. Here, we systematically evaluated the dependence of pKa values on chain length and number of double bonds by measuring the ζ-potential of liposomes reconstituted with FFA at different pH values. The experimentally obtained intrinsic pKa values (6.25, 6.93, and 7.28 for DOPC membranes) increased with FFA chain length (C16, C18, and C20), indicating that the hydrophobic energy of transfer into the bilayer is an important pKa determinant. The observed pKa decrease in DOPC with increasing number of FFA double bonds (7.28, 6.49, 6.16, and 6.13 for C20:0, C20:1, C20:2, and C20:4, respectively) is in line with a decrease in transfer energy. Molecular dynamic simulations revealed that the ionized carboxylic group of the FFAs occupied a fixed position in the bilayer independent of chain length, underlining the importance of Born energy. We conclude that pKa is determined by the interplay between the energetic costs for 1) burying the charged moiety into the lipid bilayer and 2) transferring the hydrophobic protonated FFA into the bilayer.
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38
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Škulj S, Vazdar M. Calculation of apparent pK a values of saturated fatty acids with different lengths in DOPC phospholipid bilayers. Phys Chem Chem Phys 2019; 21:10052-10060. [PMID: 31046041 DOI: 10.1039/c9cp01204d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We performed all-atom molecular dynamics simulations and calculated free energy profiles and apparent pKa values for neutral and anionic forms of single myristic (C14:0), palmitic (C16:0) and stearic (C18:0) fatty acid embedded in a DOPC bilayer and explicit water solvent. We showed that the neutral forms of the fatty acids are stabilized inside the bilayer by hydrogen bonding of a fatty acid carboxylic group with DOPC phosphate and carbonyl groups. In contrast to the neutral form, the anionic forms of the fatty acids are shifted towards the water-membrane interface and are instead stabilized by hydrogen bonding to interfacial water. By using umbrella sampling simulations, we calculated free energies of stabilization and revealed that the free energy of stabilization inside the bilayer increases with the chain length for both the neutral and deprotonated forms. On the other hand, the free energies of flip-flop of both the neutral and anionic forms are constant upon the prolongation of the fatty acid. Based on the free energy curves, we also calculated apparent fatty acid pKa,app values in the bilayer, which are 7.0, 7.2 and 6.3 for myristic, palmitic and stearic acid and are increased by several pKa units compared to the corresponding pKa values in water. By further analysis of the calculated curves we found that spontaneous protonation of fatty acid anions takes place in the bilayer interior at ca. 1.4 nm from the bilayer center for all studied fatty acids.
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Affiliation(s)
- Sanja Škulj
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
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39
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Pohl EE, Rupprecht A, Macher G, Hilse KE. Important Trends in UCP3 Investigation. Front Physiol 2019; 10:470. [PMID: 31133866 PMCID: PMC6524716 DOI: 10.3389/fphys.2019.00470] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 04/04/2019] [Indexed: 11/13/2022] Open
Abstract
Membrane uncoupling protein 3 (UCP3), a member of the mitochondrial uncoupling protein family, was discovered in 1997. UCP3's properties, such as its high homology to other mitochondrial carriers, especially to UCP2, its short lifetime and low specificity of UCP3 antibodies, have hindered progress in understanding its biological function and transport mechanism over decades. The abundance of UCP3 is highest in murine brown adipose tissue (BAT, 15.0 pmol/mg protein), compared to heart (2.7 pmol/mg protein) and the gastrocnemius muscle (1.7 pmol/mg protein), but it is still 400-fold lower than the abundance of UCP1, a biomarker for BAT. Investigation of UCP3 reconstituted in planar bilayer membranes revealed that it transports protons only when activated by fatty acids (FA). Although purine nucleotides (PN) inhibit UCP3-mediated transport, the molecular mechanism differs from that of UCP1. It remains a conundrum that two homologous proton-transporting proteins exist within the same tissue. Recently, we proposed that UCP3 abundance directly correlates with the degree of FA β-oxidation in cell metabolism. Further development in this field implies that UCP3 may have dual function in transporting substrates, which have yet to be identified, alongside protons. Evaluation of the literature with respect to UCP3 is a complex task because (i) UCP3 features are often extrapolated from its "twin" UCP2 without additional proof, and (ii) the specificity of antibodies against UCP3 used in studies is rarely evaluated. In this review, we primarily focus on recent findings obtained for UCP3 in biological and biomimetic systems.
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Affiliation(s)
- Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
- Institute of Pharmacology and Toxicology, Rostock University Medical Center, Rostock, Germany
| | - Gabriel Macher
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Karolina E. Hilse
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
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Ogunbona OB, Claypool SM. Emerging Roles in the Biogenesis of Cytochrome c Oxidase for Members of the Mitochondrial Carrier Family. Front Cell Dev Biol 2019; 7:3. [PMID: 30766870 PMCID: PMC6365663 DOI: 10.3389/fcell.2019.00003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022] Open
Abstract
The mitochondrial carrier family (MCF) is a group of transport proteins that are mostly localized to the inner mitochondrial membrane where they facilitate the movement of various solutes across the membrane. Although these carriers represent potential targets for therapeutic application and are repeatedly associated with human disease, research on the MCF has not progressed commensurate to their physiologic and pathophysiologic importance. Many of the 53 MCF members in humans are orphans and lack known transport substrates. Even for the relatively well-studied members of this family, such as the ADP/ATP carrier and the uncoupling protein, there exist fundamental gaps in our understanding of their biological roles including a clear rationale for the existence of multiple isoforms. Here, we briefly review this important family of mitochondrial carriers, provide a few salient examples of their diverse metabolic roles and disease associations, and then focus on an emerging link between several distinct MCF members, including the ADP/ATP carrier, and cytochrome c oxidase biogenesis. As the ADP/ATP carrier is regarded as the paradigm of the entire MCF, its newly established role in regulating translation of the mitochondrial genome highlights that we still have a lot to learn about these metabolite transporters.
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Affiliation(s)
- Oluwaseun B. Ogunbona
- Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
- Department of Pathology & Laboratory Medicine, School of Medicine, Emory University, Atlanta, GA, United States
| | - Steven M. Claypool
- Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
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von Rudorff GF, Watermann T, Guo XY, Sebastiani D. Conformational Space of a Polyphilic Molecule with a Fluorophilic Side Chain Integrated in a DPPC Bilayer. J Comput Chem 2019; 38:576-583. [PMID: 28211109 DOI: 10.1002/jcc.24711] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 12/21/2022]
Abstract
We investigate the conformational space of a polyphilic molecule with hydrophilic, lipophilic and fluorophilic parts inserted as a transmembrane agent into a dipalmitoylphosphatidylcholine bilayer by means of all-atom molecular dynamics simulations. Special focus is put on the competing structural driving forces arising from the hydrophilic, lipophilic and fluorophilic side chains and the aromatic backbone of the polyphile. We observe a significant difference between the lipophilic and the fluorophilic side chains regarding their intramembrane distribution. While the lipophilic groups remain membrane-centered, the fluorophilic parts tend to orient toward the phosphate headgroups. This trend is important for understanding the influence of polyphile agents on the properties of phospholipid membranes. From a fundamental point of view, our computed distribution functions of the side chains are related to the interplay of sterical, enthalpic and entropic driving forces. Our findings illustrate the potential of rationally designed membrane additives which can be exploited to tune the properties of phospholipid membranes. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Guido F von Rudorff
- Department of Physics and Astronomy, University College London, Gower Street, London, United Kingdom.,Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, Halle, 06120, Germany
| | - Tobias Watermann
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, Halle, 06120, Germany
| | - Xiang-Yang Guo
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, Halle, 06120, Germany
| | - Daniel Sebastiani
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, Halle, 06120, Germany
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Jay AG, Hamilton JA. The enigmatic membrane fatty acid transporter CD36: New insights into fatty acid binding and their effects on uptake of oxidized LDL. Prostaglandins Leukot Essent Fatty Acids 2018; 138:64-70. [PMID: 27288302 DOI: 10.1016/j.plefa.2016.05.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/11/2016] [Indexed: 12/15/2022]
Abstract
The scavenger receptor CD36 binds numerous small biomolecules, including fatty acids, and even large ligands such as oxidized LDL, for which it is considered a receptor. Although CD36 has often been postulated to "transport" fatty acids across the plasma membrane, fatty acids translocation (mass transport or kinetics) was not affected by expression of CD36 in HEK293 cells; however, esterification of fatty acids (cellular uptake) was increased. These recent results from our lab are consistent with the established mechanism of fatty acid entry into cells by passive diffusion (flip-flop) and also with the well-documented enhancement of uptake of fatty acids by CD36 in other cell types. A fascinating new discovery is that CD36 has multiple fatty acid binding sites on the extracellular domain of CD36. As illuminated by new methodologies that we have applied, these sites have high affinity and exhibit rapid exchange with the medium. In an initial study of functional consequences of binding, several dietary fatty acids enhanced uptake of oxidized LDL into HEK293 cells expressing CD36. This is the first established link between physical binding of fatty acids and a function of CD36, and has implications for obesity and atherosclerosis. New methods as those used in our study could also be applied to elucidate other functional roles of fatty acid binding to CD36.
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Affiliation(s)
- Anthony G Jay
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA 02118, United States; Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, United States
| | - James A Hamilton
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA 02118, United States.
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Abstract
Phospholipids are major constituents of biological membranes. The fatty acyl chain composition of phospholipids determines the biophysical properties of membranes and thereby affects their impact on biological processes. The composition of fatty acyl chains is also actively regulated through a deacylation and reacylation pathway called Lands' cycle. Recent studies of mouse genetic models have demonstrated that lysophosphatidylcholine acyltransferases (LPCATs), which catalyze the incorporation of fatty acyl chains into the sn-2 site of phosphatidylcholine, play important roles in pathophysiology. Two LPCAT family members, LPCAT1 and LPCAT3, have been particularly well studied. LPCAT1 is crucial for proper lung function due to its role in pulmonary surfactant biosynthesis. LPCAT3 maintains systemic lipid homeostasis by regulating lipid absorption in intestine, lipoprotein secretion, and de novo lipogenesis in liver. Mounting evidence also suggests that changes in LPCAT activity may be potentially involved in pathological conditions, including nonalcoholic fatty liver disease, atherosclerosis, viral infections, and cancer. Pharmacological manipulation of LPCAT activity and membrane phospholipid composition may provide new therapeutic options for these conditions.
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Affiliation(s)
- Bo Wang
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90272, USA;
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90272, USA;
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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Brain docosahexaenoic acid uptake and metabolism. Mol Aspects Med 2018; 64:109-134. [PMID: 29305120 DOI: 10.1016/j.mam.2017.12.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 12/22/2022]
Abstract
Docosahexaenoic acid (DHA) is the most abundant n-3 polyunsaturated fatty acid in the brain where it serves to regulate several important processes and, in addition, serves as a precursor to bioactive mediators. Given that the capacity of the brain to synthesize DHA locally is appreciably low, the uptake of DHA from circulating lipid pools is essential to maintaining homeostatic levels. Although, several plasma pools have been proposed to supply the brain with DHA, recent evidence suggests non-esterified-DHA and lysophosphatidylcholine-DHA are the primary sources. The uptake of DHA into the brain appears to be regulated by a number of complementary pathways associated with the activation and metabolism of DHA, and may provide mechanisms for enrichment of DHA within the brain. Following entry into the brain, DHA is esterified into and recycled amongst membrane phospholipids contributing the distribution of DHA in brain phospholipids. During neurotransmission and following brain injury, DHA is released from membrane phospholipids and converted to bioactive mediators which regulate signaling pathways important to synaptogenesis, cell survival, and neuroinflammation, and may be relevant to treating neurological diseases. In the present review, we provide a comprehensive overview of brain DHA metabolism, encompassing many of the pathways and key enzymatic regulators governing brain DHA uptake and metabolism. In addition, we focus on the release of non-esterified DHA and subsequent production of bioactive mediators and the evidence of their proposed activity within the brain. We also provide a brief review of the evidence from post-mortem brain analyses investigating DHA levels in the context of neurological disease and mood disorder, highlighting the current disparities within the field.
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Tracey TJ, Steyn FJ, Wolvetang EJ, Ngo ST. Neuronal Lipid Metabolism: Multiple Pathways Driving Functional Outcomes in Health and Disease. Front Mol Neurosci 2018; 11:10. [PMID: 29410613 PMCID: PMC5787076 DOI: 10.3389/fnmol.2018.00010] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 01/08/2018] [Indexed: 12/12/2022] Open
Abstract
Lipids are a fundamental class of organic molecules implicated in a wide range of biological processes related to their structural diversity, and based on this can be broadly classified into five categories; fatty acids, triacylglycerols (TAGs), phospholipids, sterol lipids and sphingolipids. Different lipid classes play major roles in neuronal cell populations; they can be used as energy substrates, act as building blocks for cellular structural machinery, serve as bioactive molecules, or a combination of each. In amyotrophic lateral sclerosis (ALS), dysfunctions in lipid metabolism and function have been identified as potential drivers of pathogenesis. In particular, aberrant lipid metabolism is proposed to underlie denervation of neuromuscular junctions, mitochondrial dysfunction, excitotoxicity, impaired neuronal transport, cytoskeletal defects, inflammation and reduced neurotransmitter release. Here we review current knowledge of the roles of lipid metabolism and function in the CNS and discuss how modulating these pathways may offer novel therapeutic options for treating ALS.
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Affiliation(s)
- Timothy J Tracey
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Frederik J Steyn
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia
| | - Shyuan T Ngo
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, Australia.,Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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The Flip-Flop Diffusion Mechanism across Lipids in a Hybrid Bilayer Membrane. Biophys J 2017; 110:2451-2462. [PMID: 27276263 DOI: 10.1016/j.bpj.2016.04.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/03/2016] [Accepted: 04/25/2016] [Indexed: 12/31/2022] Open
Abstract
In this study, we examine the mechanism of flip-flop diffusion of proton carriers across the lipid layer of a hybrid bilayer membrane (HBM). The HBM consists of a lipid monolayer appended on top of a self-assembled monolayer containing a Cu-based O2 reduction catalyst on a Au electrode. The flip-flop diffusion rates of the proton carriers dictate the kinetics of O2 reduction by the electrocatalyst. By varying both the tail lengths of the proton carriers and the lipids, we find the combinations of lengths that maximize the flip-flop diffusion rate. These experimental results combined with biophysical modeling studies allow us to propose a detailed mechanism for transmembrane flip-flop diffusion in HBM systems, which involves the bending of the alkyl tail of the proton carrier as the rate-determining step. Additional studies with an unbendable proton carrier further validate these mechanistic findings.
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Crichton PG, Lee Y, Kunji ERS. The molecular features of uncoupling protein 1 support a conventional mitochondrial carrier-like mechanism. Biochimie 2017; 134:35-50. [PMID: 28057583 PMCID: PMC5395090 DOI: 10.1016/j.biochi.2016.12.016] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/24/2016] [Indexed: 12/14/2022]
Abstract
Uncoupling protein 1 (UCP1) is an integral membrane protein found in the mitochondrial inner membrane of brown adipose tissue, and facilitates the process of non-shivering thermogenesis in mammals. Its activation by fatty acids, which overcomes its inhibition by purine nucleotides, leads to an increase in the proton conductance of the inner mitochondrial membrane, short-circuiting the mitochondrion to produce heat rather than ATP. Despite 40 years of intense research, the underlying molecular mechanism of UCP1 is still under debate. The protein belongs to the mitochondrial carrier family of transporters, which have recently been shown to utilise a domain-based alternating-access mechanism, cycling between a cytoplasmic and matrix state to transport metabolites across the inner membrane. Here, we review the protein properties of UCP1 and compare them to those of mitochondrial carriers. UCP1 has the same structural fold as other mitochondrial carriers and, in contrast to past claims, is a monomer, binding one purine nucleotide and three cardiolipin molecules tightly. The protein has a single substrate binding site, which is similar to those of the dicarboxylate and oxoglutarate carriers, but also contains a proton binding site and several hydrophobic residues. As found in other mitochondrial carriers, UCP1 has two conserved salt bridge networks on either side of the central cavity, which regulate access to the substrate binding site in an alternating way. The conserved domain structures and mobile inter-domain interfaces are consistent with an alternating access mechanism too. In conclusion, UCP1 has retained all of the key features of mitochondrial carriers, indicating that it operates by a conventional carrier-like mechanism.
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Affiliation(s)
- Paul G Crichton
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
| | - Yang Lee
- Laboratory of Molecular Biology, Medical Research Council, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Edmund R S Kunji
- Mitochondrial Biology Unit, Medical Research Council, Cambridge Biomedical Campus, Wellcome Trust, MRC Building, Hills Road, Cambridge CB2 0XY, United Kingdom.
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Dubinin MV, Stepanova AE, Scherbakov KA, Samartsev VN, Belosludtsev KN. Ca2+-dependent aggregation and permeabilization of erythrocytes by ω-hydroxypalmitic and α, ω-hexadecandioic acids. Biophysics (Nagoya-shi) 2017. [DOI: 10.1134/s0006350916050055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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