1
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Vidović N, Knez M, Ranić M, Faid F, Jović D, Glibetic M, Takić M. Comparative assessment of erythrocyte sphingolipid levels as potential cardiovascular health markers in women from Libya and Serbia: a small-scale study. Libyan J Med 2023; 18:2264568. [PMID: 37804002 PMCID: PMC10561568 DOI: 10.1080/19932820.2023.2264568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 09/25/2023] [Indexed: 10/08/2023] Open
Abstract
Aim: Cardiovascular diseases (CVDs) represent the major cause of morbidity and mortality worldwide including Libya, where they account for 43% of all deaths. Sphingolipids are involved in the pathology of numerous diseases including cardiovascular diseases and are proposed as potential biomarkers of cardiovascular health that could be more effective compared to traditional clinical biomarkers. The aim of this study was to determine the sphingolipid content in the erythrocyte membrane of Libyan migrant and Serbian resident women. In addition, to examine if sphingolipid levels could be used as a novel indicator of cardiovascular risk, we evaluated possible correlations with some well-established biomarkers of cardiovascular health.Materials and Methods: A total of 13 Libyan and 15 Serbian healthy women participated in the study. The high-performance version thin-layer chromatography (HPTLC) using the image analysis tool JustTLC was applied for quantification of erythrocytes' sphingolipids.Results: Lower mean values of erythrocytes' sphingolipids and cholesterol concentrations were found in the group of Libyan emigrants compared to Serbian resident women. Besides, in this group of apparently healthy women (n = 28), the sphingolipid content of erythrocytes was inversely related to the Omega-3 index (r =-0.492, p = 0.008) and directly linked to vitamin D status (r = 0.433, p = 0.021) and membrane cholesterol levels (r = 0.474, p = 0.011).Conclusion: The erythrocytes' sphingolipid levels should be measured/assessed as an additional biomarker of CV health, by applying a simple and routine method. Still, further investigation in a larger population-specific context is warranted.
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Affiliation(s)
- Nevena Vidović
- Institute for Medical Research, National Institute of Republic of Serbia, Centre of Research Excellence in Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia
| | - Marija Knez
- Institute for Medical Research, National Institute of Republic of Serbia, Centre of Research Excellence in Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia
| | - Marija Ranić
- Institute for Medical Research, National Institute of Republic of Serbia, Centre of Research Excellence in Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia
| | - Fathia Faid
- Institute for Medical Research, National Institute of Republic of Serbia, Centre of Research Excellence in Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia
- Faculty of Nursing, Misurata University, Misrata, Libya
| | - Dragana Jović
- Center for Hygiene and Human Ecology, Institute of Public Health of Serbia "Dr Milan Jovanović Batut", Belgrade, Serbia
| | - Marija Glibetic
- Institute for Medical Research, National Institute of Republic of Serbia, Centre of Research Excellence in Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia
| | - Marija Takić
- Institute for Medical Research, National Institute of Republic of Serbia, Centre of Research Excellence in Nutrition and Metabolism, University of Belgrade, Belgrade, Serbia
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2
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Schumacher J, Nienhaus A, Heber S, Matylitsky J, Chaves-Olarte E, Rodríguez C, Barth H, Papatheodorou P. Exploring the inhibitory potential of the antiarrhythmic drug amiodarone against Clostridioides difficile toxins TcdA and TcdB. Gut Microbes 2023; 15:2256695. [PMID: 37749884 PMCID: PMC10524773 DOI: 10.1080/19490976.2023.2256695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 09/05/2023] [Indexed: 09/27/2023] Open
Abstract
The intestinal pathogen Clostridioides difficile is the leading cause of antibiotic-associated diarrhea and pseudomembranous colitis in humans. The symptoms of C. difficile-associated diseases (CDADs) are directly associated with the pathogen's toxins TcdA and TcdB, which enter host cells and inactivate Rho and/or Ras GTPases by glucosylation. Membrane cholesterol is crucial during the intoxication process of TcdA and TcdB, and likely involved during pore formation of both toxins in endosomal membranes, a key step after cellular uptake for the translocation of the glucosyltransferase domain of both toxins from endosomes into the host cell cytosol. The licensed drug amiodarone, a multichannel blocker commonly used in the treatment of cardiac dysrhythmias, is also capable of inhibiting endosomal acidification and, as shown recently, cholesterol biosynthesis. Thus, we were keen to investigate in vitro with cultured cells and human intestinal organoids, whether amiodarone preincubation protects from TcdA and/or TcdB intoxication. Amiodarone conferred protection against both toxins independently and in combination as well as against toxin variants from the clinically relevant, epidemic C. difficile strain NAP1/027. Further mechanistic studies suggested that amiodarone's mode-of-inhibition involves also interference with the translocation pore of both toxins. Our study opens the possibility of repurposing the licensed drug amiodarone as a novel pan-variant antitoxin therapeutic in the context of CDADs.
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Affiliation(s)
- Judith Schumacher
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
| | - Astrid Nienhaus
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
| | - Sebastian Heber
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
| | - Jauheni Matylitsky
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
| | - Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales and Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - César Rodríguez
- Centro de Investigación en Enfermedades Tropicales and Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Holger Barth
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
| | - Panagiotis Papatheodorou
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
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3
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Abstract
The interaction of lipids with G-protein-coupled receptors (GPCRs) has been shown to modulate and dictate several aspects of GPCR organization and function. Diverse lipid interaction sites have been identified from structural biology, bioinformatics, and molecular dynamics studies. For example, multiple cholesterol interaction sites have been identified in the serotonin1A receptor, along with distinct and overlapping sphingolipid interaction sites. How these lipids interact with each other and what is the resultant effect on the receptor is still not clear. In this work, we have analyzed lipid-lipid crosstalk at the receptor of the serotonin1A receptor embedded in a membrane bilayer that mimics the neuronal membrane composition by long coarse-grain simulations. Using a set of similarity coefficients, we classified lipids that bind at the receptor together as synergistic cobinding, and those that bind individually as competitive. Our results show that certain lipids interact with the serotonin1A receptor in synergy with each other. Not surprisingly, the ganglioside GM1 and cholesterol show a synergistic cobinding, along with the relatively uncommon GM1-phosphatidylethanolamine (PE) and cholesterol-PE synergy. In contrast, certain lipid pairs such as cholesterol and sphingomyelin appear to be in competition at several sites, despite their coexistence in lipid nanodomains. In addition, we observed intralipid competition between two lipid tails, with the receptor exhibiting increased interactions with the unsaturated lipid tails. We believe our work represents an important step in understanding the diversity of GPCR-lipid interactions and exploring synergistic cobinding and competition in natural membranes.
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Affiliation(s)
- Madhura Mohole
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune411 008, India.,Academy of Scientific and Innovative Research, Ghaziabad201 002, India
| | - Durba Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune411 008, India.,Academy of Scientific and Innovative Research, Ghaziabad201 002, India
| | - Amitabha Chattopadhyay
- Academy of Scientific and Innovative Research, Ghaziabad201 002, India.,CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad500 007, India
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4
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Niesor EJ, Nader E, Perez A, Lamour F, Benghozi R, Remaley A, Thein SL, Connes P. Red Blood Cell Membrane Cholesterol May Be a Key Regulator of Sickle Cell Disease Microvascular Complications. Membranes (Basel) 2022; 12:1134. [PMID: 36422126 PMCID: PMC9694375 DOI: 10.3390/membranes12111134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/06/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Cell membrane lipid composition, especially cholesterol, affects many functions of embedded enzymes, transporters and receptors in red blood cells (RBC). High membrane cholesterol content affects the RBCs' main vital function, O2 and CO2 transport and delivery, with consequences on peripheral tissue physiology and pathology. A high degree of deformability of RBCs is required to accommodate the size of micro-vessels with diameters significantly lower than RBCs. The potential therapeutic role of high-density lipoproteins (HDL) in the removal of cholesterol and its activity regarding maintenance of an optimal concentration of RBC membrane cholesterol have not been well investigated. On the contrary, the focus for HDL research has mainly been on the clearance of cholesterol accumulated in atherosclerotic macrophages and plaques. Since all interventions aiming at decreasing cardiovascular diseases by increasing the plasma level of HDL cholesterol have failed so far in large outcome studies, we reviewed the potential role of HDL to remove excess membrane cholesterol from RBC, especially in sickle cell disease (SCD). Indeed, abundant literature supports a consistent decrease in cholesterol transported by all plasma lipoproteins in SCD, in addition to HDL, low- (LDL) and very low-density lipoproteins (VLDL). Unexpectedly, these decreases in plasma were associated with an increase in RBC membrane cholesterol. The concentration and activity of the main enzyme involved in the removal of cholesterol and generation of large HDL particles-lecithin cholesterol ester transferase (LCAT)-are also significantly decreased in SCD. These observations might partially explain the decrease in RBC deformability, diminished gas exchange and tendency of RBCs to aggregate in SCD. We showed that incubation of RBC from SCD patients with human HDL or the HDL-mimetic peptide Fx5A improves the impaired RBC deformability and decreases intracellular reactive oxygen species levels. We propose that the main physiological role of HDL is to regulate the cholesterol/phospholipid ratio (C/PL), which is fundamental to the transport of oxygen and its delivery to peripheral tissues.
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Affiliation(s)
| | - Elie Nader
- Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, 69007 Lyon, France
| | - Anne Perez
- Hartis Pharma SA Nyon, 1260 Nyon, Switzerland
| | | | | | - Alan Remaley
- National Institutes of Health, Bethesda, MD 20814, USA
| | | | - Philippe Connes
- Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, 69007 Lyon, France
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5
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Rikihisa Y. The "Biological Weapons" of Ehrlichia chaffeensis: Novel Molecules and Mechanisms to Subjugate Host Cells. Front Cell Infect Microbiol 2022; 11:830180. [PMID: 35155275 PMCID: PMC8834651 DOI: 10.3389/fcimb.2021.830180] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/20/2021] [Indexed: 12/22/2022] Open
Abstract
Ehrlichia chaffeensis is an obligatory intracellular bacterium that causes human monocytic ehrlichiosis, an emerging, potentially fatal tick-borne infectious disease. The bacterium enters human cells via the binding of its unique outer-membrane invasin EtpE to the cognate receptor DNase X on the host-cell plasma membrane; this triggers actin polymerization and filopodia formation at the site of E. chaffeensis binding, and blocks activation of phagocyte NADPH oxidase that catalyzes the generation of microbicidal reactive oxygen species. Subsequently, the bacterium replicates by hijacking/dysregulating host-cell functions using Type IV secretion effectors. For example, the Ehrlichia translocated factor (Etf)-1 enters mitochondria and inhibits mitochondria-mediated apoptosis of host cells. Etf-1 also induces autophagy mediated by the small GTPase RAB5, the result being the liberation of catabolites for proliferation inside host cells. Moreover, Etf-2 competes with the RAB5 GTPase-activating protein, for binding to RAB5-GTP on the surface of E. chaffeensis inclusions, which blocks GTP hydrolysis and consequently prevents the fusion of inclusions with host-cell lysosomes. Etf-3 binds ferritin light chain to induce ferritinophagy to obtain intracellular iron. To enable E. chaffeensis to rapidly adapt to the host environment and proliferate, the bacterium must acquire host membrane cholesterol and glycerophospholipids for the purpose of producing large amounts of its own membrane. Future studies on the arsenal of unique Ehrlichia molecules and their interplay with host-cell components will undoubtedly advance our understanding of the molecular mechanisms of obligatory intracellular infection and may identify hitherto unrecognized signaling pathways of human hosts. Such data could be exploited for development of treatment and control measures for ehrlichiosis as well as other ailments that potentially could involve the same host-cell signaling pathways that are appropriated by E. chaffeensis.
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Affiliation(s)
- Yasuko Rikihisa
- Laboratory of Molecular, Cellular, and Environmental Rickettsiology, Department of Veterinary Biosciences, College of Veterinary Medicine, Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
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6
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Kuo MS, Chuang CH, Cheng HC, Lin HR, Wang JS, Hsu K. Different Involvement of Band 3 in Red Cell Deformability and Osmotic Fragility-A Comparative GP.Mur Erythrocyte Study. Cells 2021; 10:3369. [PMID: 34943876 DOI: 10.3390/cells10123369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 11/21/2022] Open
Abstract
GP.Mur is a clinically important red blood cell (RBC) phenotype in Southeast Asia. The molecular entity of GP.Mur is glycophorin B-A-B hybrid protein that promotes band 3 expression and band 3–AQP1 interaction, and alters the organization of band 3 complexes with Rh/RhAG complexes. GP.Mur+ RBCs are more resistant to osmotic stress. To explore whether GP.Mur+ RBCs could be structurally more resilient, we compared deformability and osmotic fragility of fresh RBCs from 145 adults without major illness (47% GP.Mur). We also evaluated potential impacts of cellular and lipid factors on RBC deformability and osmotic resistivity. Contrary to our anticipation, these two physical properties were independent from each other based on multivariate regression analyses. GP.Mur+ RBCs were less deformable than non-GP.Mur RBCs. We also unexpectedly found 25% microcytosis in GP.Mur+ female subjects (10/40). Both microcytosis and membrane cholesterol reduced deformability, but the latter was only observed in non-GP.Mur and not GP.Mur+ normocytes. The osmotic fragility of erythrocytes was not affected by microcytosis; instead, larger mean corpuscular volume (MCV) increased the chances of hypotonic burst. From comparison with GP.Mur+ RBCs, higher band 3 expression strengthened the structure of RBC membrane and submembranous cytoskeletal networks and thereby reduced cell deformability; stronger band 3–AQP1 interaction additionally supported osmotic resistance. Thus, red cell deformability and osmotic resistivity involve distinct structural–functional roles of band 3.
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7
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Jose M, Sivanand A, Channakeshava C. Membrane Cholesterol Is a Critical Determinant for Hippocampal Neuronal Polarity. Front Mol Neurosci 2021; 14:746211. [PMID: 34744625 PMCID: PMC8566733 DOI: 10.3389/fnmol.2021.746211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
Maintaining a normal cholesterol balance is crucial for the functioning of a healthy brain. Dysregulation in cholesterol metabolism and homeostasis in the brain have been correlated to various neurological disorders. The majority of previous studies in primary cultures focus on the role of cholesterol balance in neuronal development after polarity has been established. Here we have investigated how transient alteration of membrane lipids, specifically cholesterol, affects neuronal development and polarity in developing hippocampal neurons prior to polarity establishment, soon after initiation of neurite outgrowth. We observed that temporary cholesterol perturbation affects axonal and dendritic development differentially in an opposing manner. Transient membrane cholesterol deficiency increased neuronal population with a single neurite, simultaneously generating a second population of neurons with supernumerary axons. Brief replenishment of cholesterol immediately after cholesterol sequestering rescued neuronal development defects and restored polarity. The results showed a small window of cholesterol concentration to be complementing neurite outgrowth, polarity reestablishment, and in determining the normal neuronal morphology, emphasizing the critical role of precise membrane lipid balance in defining the neuronal architecture. Membrane cholesterol enhancement modified neurite outgrowth but did not significantly alter polarity. Cholesterol sequestering at later stages of development has shown to enhance neurite outgrowth, whereas distinct effects for neurite development and polarity were observed at early developmental stages, signifying the relevance of precise membrane cholesterol balance in altering neuronal physiology. Our results confirm cholesterol to be a key determinant for axo-dendritic specification and neuronal architecture and emphasize the possibility to reverse neuronal developmental defects caused by cholesterol deficiency by modulating membrane cholesterol during the early developmental stages.
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Affiliation(s)
- Mini Jose
- Centre for Neuroscience, Indian institute of Science, Bangalore, India
| | - Aiswarya Sivanand
- Centre for Neuroscience, Indian institute of Science, Bangalore, India
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8
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Granados ST, Latorre R, Torres YP. The Membrane Cholesterol Modulates the Interaction Between 17-βEstradiol and the BK Channel. Front Pharmacol 2021; 12:687360. [PMID: 34177597 PMCID: PMC8226216 DOI: 10.3389/fphar.2021.687360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
BK channels are composed by the pore forming α subunit and, in some tissues, is associated with different accessory β subunits. These proteins modify the biophysical properties of the channel, amplifying the range of BK channel activation according to the physiological context. In the vascular cells, the pore forming BKα subunit is expressed with the β1 subunit, where they play an essential role in the modulation of arterial tone and blood pressure. In eukaryotes, cholesterol is a structural lipid of the cellular membrane. Changes in the ratio of cholesterol content in the plasma membrane (PM) regulates the BK channel activation altering its open probability, and hence, vascular contraction. It has been shown that the estrogen 17β-Estradiol (E2) causes a vasodilator effect in vascular cells, inducing a leftward shift in the V0.5 of the GV curve. Here, we evaluate whether changes in the membrane cholesterol concentration modify the effect that E2 induces on the BKα/β1 channel activity. Using binding and electrophysiology assays after cholesterol depletion or enrichment, we show that the cholesterol enrichment significantly decreases the expression of the α subunit, while cholesterol depletion increased the expression of that α subunit. Additionally, we demonstrated that changes in the membrane cholesterol cause the loss of the modulatory effect of E2 on the BKα/β1 channel activity, without affecting the E2 binding to the complex. Our data suggest that changes in membrane cholesterol content could affect channel properties related to the E2 effect on BKα/β1 channel activity. Finally, the results suggest that an optimal membrane cholesterol content is essential for the activation of BK channels through the β1 subunit.
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Affiliation(s)
- Sara T Granados
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia.,Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Yolima P Torres
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia
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9
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Wang H, Arias EB, Cartee GD. Reduced membrane cholesterol content in skeletal muscle is not essential for greater insulin-stimulated glucose uptake after acute exercise by rats. Appl Physiol Nutr Metab 2021; 46:685-689. [PMID: 33765397 DOI: 10.1139/apnm-2021-0130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
One exercise session can elevate insulin-stimulated glucose uptake (GU) by skeletal muscle, but it is uncertain if this effect is accompanied by altered membrane cholesterol content, which is reportedly inversely related to insulin-stimulated GU. Muscles from sedentary (SED) or exercised 3 h post-exercise (3hPEX) rats were evaluated for GU, membrane cholesterol, and phosphorylation of cholesterol regulatory proteins (pHMCGRSer872 and pABCA1Ser2054). Insulin-stimulated GU for 3hPEX exceeded SED. Membrane cholesterol, pHMCGRSer872 and pABCA1Ser2054 did not differ between groups. Novelty: Alterations in membrane cholesterol and phosphorylation of proteins that regulate muscle cholesterol are not essential for elevated insulin-stimulated GU in skeletal muscle after acute exercise.
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Affiliation(s)
- Haiyan Wang
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-1048, USA.,Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-1048, USA.,Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-1048, USA.,Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, MI 48109-1048, USA
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10
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Torralba J, de la Arada I, Carravilla P, Insausti S, Rujas E, Largo E, Eggeling C, Arrondo JLR, Apellániz B, Nieva JL. Cholesterol Constrains the Antigenic Configuration of the Membrane-Proximal Neutralizing HIV-1 Epitope. ACS Infect Dis 2020; 6:2155-2168. [PMID: 32584020 DOI: 10.1021/acsinfecdis.0c00243] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The envelope glycoprotein (Env) enables HIV-1 cell entry through fusion of host-cell and viral membranes induced by the transmembrane subunit gp41. Antibodies targeting the C-terminal sequence of the membrane-proximal external region (C-MPER) block the fusogenic activity of gp41 and achieve neutralization of divergent HIV-1 strains and isolates. Thus, recreating the structure that generates broadly neutralizing C-MPER antibodies during infection is a major goal in HIV vaccine development. Here, we have reconstituted a peptide termed CpreTM-TMD in a membrane environment. This peptide contains the C-MPER epitope and the minimum TMD residues required for the anchorage of the Env glycoprotein to the viral membrane. In addition, we have used antibody 10E8 variants to gauge the antigenic configuration attained by CpreTM-TMD as a function of the membrane cholesterol content, a functional determinant of the HIV envelope and liposome-based vaccines. Differential binding of the 10E8 variants and the trend of the IgG responses recovered from rabbits immunized with liposome-peptide formulations, suggested that cholesterol may restrict 10E8 accessibility to the C-MPER epitope. Our data ruled out the destabilization of the lipid bilayer architecture in CpreTM-TMD-containing membranes, and pointed to the perturbation of the helical conformation by lipid packing as the cause of the antigenic configuration loss induced by cholesterol. Overall, our results provide additional insights into the structural basis of the Env complex anchoring to membranes, and suggest new approaches to the design of effective immunogens directed against the near pan-neutralizing HIV-1 epitope C-MPER.
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Affiliation(s)
- Johana Torralba
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Igor de la Arada
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Pablo Carravilla
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Sara Insausti
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Edurne Rujas
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Immunology, Microbiology and Parasitology, Medicine and Odontology Faculty, University of Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Christian Eggeling
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, OX3 9DS Oxford, U.K
| | - José L R Arrondo
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Beatriz Apellániz
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Paseo de la Universidad, 7, 01006 Vitoria-Gasteiz, Spain
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
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11
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Chen Y, Huang K, Chen LK, Wu HY, Hsu CY, Tsai YS, Ko WC, Tsai PJ. Membrane Cholesterol Is Crucial for Clostridium difficile Surface Layer Protein Binding and Triggering Inflammasome Activation. Front Immunol 2020; 11:1675. [PMID: 32849582 PMCID: PMC7411348 DOI: 10.3389/fimmu.2020.01675] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/23/2020] [Indexed: 12/12/2022] Open
Abstract
Clostridium difficile, an obligate anaerobic gram-positive bacillus, generates spores and is commonly found colonizing the human gut. Patients with C. difficile infection (CDI) often exhibit clinical manifestations of pseudomembranous colitis or antibiotic-associated diarrhea. Surface layer proteins (SLPs) are the most abundant proteins in the C. difficile cell wall, suggesting that they might involve in immune recognition. Our previous results demonstrated that C. difficile triggers inflammasome activation. Here, we found SLPs as well as C. difficile induced inflammasome activation, and in a dose-dependent manner. In addition, the cholesterol-rich microdomains on the cell membrane (also referred to as lipid rafts) are thought to be crucial for bacterial adhesion and signal transduction. We demonstrated that lipid rafts participated in C. difficile SLPs binding to the cell membrane. Fluorescence microscopy showed that membrane cholesterol depletion by methyl-β-cyclodextrin (MβCD) reduced the association of SLPs with the cell surface. The coalescence of SLPs in the cholesterol-rich microdomains was confirmed in C. difficile-infected cells. Furthermore, the inflammasome activations induced by SLPs or C. difficile were abrogated by MβCD. Our results demonstrate that SLPs recruit the lipid rafts, which may be a key step for C. difficile colonization and inducing inflammasome activation.
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Affiliation(s)
- Yu Chen
- Department of Laboratory Medicine, Mackay Memorial Hospital, New Taipei, Taiwan
| | - Kai Huang
- Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Liang-Kuei Chen
- Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan.,Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Hui-Yu Wu
- Department of Laboratory Medicine, Mackay Memorial Hospital, New Taipei, Taiwan
| | - Chih-Yu Hsu
- Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Yau-Sheng Tsai
- Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Pei-Jane Tsai
- Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan.,Department of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan.,Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
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12
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Moessinger C, Nilsson I, Muhl L, Zeitelhofer M, Heller Sahlgren B, Skogsberg J, Eriksson U. VEGF-B signaling impairs endothelial glucose transcytosis by decreasing membrane cholesterol content. EMBO Rep 2020; 21:e49343. [PMID: 32449307 PMCID: PMC7332976 DOI: 10.15252/embr.201949343] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/07/2020] [Accepted: 04/21/2020] [Indexed: 01/03/2023] Open
Abstract
Regulation of endothelial nutrient transport is poorly understood. Vascular endothelial growth factor B (VEGF‐B) signaling in endothelial cells promotes uptake and transcytosis of fatty acids from the bloodstream to the underlying tissue, advancing pathological lipid accumulation and lipotoxicity in diabetic complications. Here, we demonstrate that VEGF‐B limits endothelial glucose transport independent of fatty acid uptake. Specifically, VEGF‐B signaling impairs recycling of low‐density lipoprotein receptor (LDLR) to the plasma membrane, leading to reduced cholesterol uptake and membrane cholesterol loading. Reduced cholesterol levels in the membrane leads to a decrease in glucose transporter 1 (GLUT1)‐dependent endothelial glucose uptake. Inhibiting VEGF‐B in vivo reconstitutes membrane cholesterol levels and restores glucose uptake, which is of particular relevance for conditions involving insulin resistance and diabetic complications. In summary, our study reveals a mechanism whereby VEGF‐B regulates endothelial nutrient uptake and highlights the impact of membrane cholesterol for regulation of endothelial glucose transport.
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Affiliation(s)
- Christine Moessinger
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Ingrid Nilsson
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Lars Muhl
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Manuel Zeitelhofer
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Benjamin Heller Sahlgren
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Josefin Skogsberg
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Ulf Eriksson
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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13
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Kravtsova VV, Bouzinova EV, Chibalin AV, Matchkov VV, Krivoi II. Isoform-specific Na,K-ATPase and membrane cholesterol remodeling in motor endplates in distinct mouse models of myodystrophy. Am J Physiol Cell Physiol 2020; 318:C1030-C1041. [PMID: 32293933 DOI: 10.1152/ajpcell.00453.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Na,K-ATPase is a membrane transporter that is critically important for skeletal muscle function. Mdx and Bla/J mice are the experimental models of Duchenne muscular dystrophy and dysferlinopathy that are known to differ in the molecular mechanism of the pathology. This study examines the function of α1- and α2-Na,K-ATPase isozymes in respiratory diaphragm and postural soleus muscles from mdx and Bla/J mice compared with control С57Bl/6 mice. In diaphragm muscles, the motor endplate structure was severely disturbed (manifested by defragmentation) in mdx mice only. The endplate membrane of both Bla/J and mdx mice was depolarized due to specific loss of the α2-Na,K-ATPase electrogenic activity and its decreased membrane abundance. Total FXYD1 subunit (modulates Na,K-ATPase activity) abundance was decreased in both mouse models. However, the α2-Na,K-ATPase protein content as well as mRNA expression were specifically and significantly reduced only in mdx mice. The endplate membrane cholesterol redistribution was most pronounced in mdx mice. Soleus muscles from Bla/J and mdx mice demonstrated reduction of the α2-Na,K-ATPase membrane abundance and mRNA expression similar to the diaphragm muscles. In contrast to diaphragm, the α2-Na,K-ATPase protein content was altered in both Bla/J and mdx mice; membrane cholesterol re-distribution was not observed. Thus, the α2-Na,K-ATPase is altered in both Bla/J and mdx mouse models of chronic muscle pathology. However, despite some similarities, the α2-Na,K-ATPase and cholesterol abnormalities are more pronounced in mdx mice.
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Affiliation(s)
- Violetta V Kravtsova
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
| | | | | | | | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
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14
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Norton CE, Weise-Cross L, Ahmadian R, Yan S, Jernigan NL, Paffett ML, Naik JS, Walker BR, Resta TC. Altered Lipid Domains Facilitate Enhanced Pulmonary Vasoconstriction after Chronic Hypoxia. Am J Respir Cell Mol Biol 2020; 62:709-718. [PMID: 31945301 DOI: 10.1165/rcmb.2018-0318oc] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Chronic hypoxia (CH) augments depolarization-induced pulmonary vasoconstriction through superoxide-dependent, Rho kinase-mediated Ca2+ sensitization. Nicotinamide adenine dinucleotide phosphate oxidase and EGFR (epidermal growth factor receptor) signaling contributes to this response. Caveolin-1 regulates the activity of a variety of proteins, including EGFR and nicotinamide adenine dinucleotide phosphate oxidase, and membrane cholesterol is an important regulator of caveolin-1 protein interactions. We hypothesized that derangement of these membrane lipid domain components augments depolarization-induced Ca2+ sensitization and resultant vasoconstriction after CH. Although exposure of rats to CH (4 wk, ∼380 mm Hg) did not alter caveolin-1 expression in intrapulmonary arteries or the incidence of caveolae in arterial smooth muscle, CH markedly reduced smooth muscle membrane cholesterol content as assessed by filipin fluorescence. Effects of CH on vasoreactivity and superoxide generation were examined using pressurized, Ca2+-permeabilized, endothelium-disrupted pulmonary arteries (∼150 μm inner diameter) from CH and control rats. Depolarizing concentrations of KCl evoked greater constriction in arteries from CH rats than in those obtained from control rats, and increased superoxide production as assessed by dihydroethidium fluorescence only in arteries from CH rats. Both cholesterol supplementation and the caveolin-1 scaffolding domain peptide antennapedia-Cav prevented these effects of CH, with each treatment restoring membrane cholesterol in CH arteries to control levels. Enhanced EGF-dependent vasoconstriction after CH similarly required reduced membrane cholesterol. However, these responses to CH were not associated with changes in EGFR expression or activity, suggesting that cholesterol regulates this signaling pathway downstream of EGFR. We conclude that alterations in membrane lipid domain signaling resulting from reduced cholesterol content facilitate enhanced depolarization- and EGF-induced pulmonary vasoconstriction after CH.
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Affiliation(s)
- Charles E Norton
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Laura Weise-Cross
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Rosstin Ahmadian
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Simin Yan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Michael L Paffett
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Jay S Naik
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Benjimen R Walker
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
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15
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Endeward V, Arias-Hidalgo M, Al-Samir S, Gros G. CO₂ Permeability of Biological Membranes and Role of CO₂ Channels. Membranes (Basel) 2017; 7:E61. [PMID: 29064458 DOI: 10.3390/membranes7040061] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 01/09/2023]
Abstract
We summarize here, mainly for mammalian systems, the present knowledge of (a) the membrane CO₂ permeabilities in various tissues; (b) the physiological significance of the value of the CO₂ permeability;
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16
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Ramírez-Anguita JM, Rodríguez-Espigares I, Guixà-González R, Bruno A, Torrens-Fontanals M, Varela-Rial A, Selent J. Membrane cholesterol effect on the 5-HT 2A receptor: Insights into the lipid-induced modulation of an antipsychotic drug target. Biotechnol Appl Biochem 2017; 65:29-37. [PMID: 28877377 DOI: 10.1002/bab.1608] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The serotonin 5-hydroxytryptamine 2A (5-HT2A ) receptor is a G-protein-coupled receptor (GPCR) relevant for the treatment of CNS disorders. In this regard, neuronal membrane composition in the brain plays a crucial role in the modulation of the receptor functioning. Since cholesterol is an essential component of neuronal membranes, we have studied its effect on the 5-HT2A receptor dynamics through all-atom MD simulations. We find that the presence of cholesterol in the membrane increases receptor conformational variability in most receptor segments. Importantly, detailed structural analysis indicates that conformational variability goes along with the destabilization of hydrogen bonding networks not only within the receptor but also between receptor and lipids. In addition to increased conformational variability, we also find receptor segments with reduced variability. Our analysis suggests that this increased stabilization is the result of stabilizing effects of tightly bound cholesterol molecules to the receptor surface. Our finding contributes to a better understanding of membrane-induced alterations of receptor dynamics and points to cholesterol-induced stabilizing and destabilizing effects on the conformational variability of GPCRs.
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Affiliation(s)
- Juan Manuel Ramírez-Anguita
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - Ismael Rodríguez-Espigares
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - Ramon Guixà-González
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain.,Institut für Medizinische Physik und Biophysik, Charité, Berlin, Germany
| | - Agostino Bruno
- Department of Pharmacy, Università degli studi di Parma, Italy, Parma
| | - Mariona Torrens-Fontanals
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - Alejandro Varela-Rial
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Department of Experimental and Health Sciences of Pompeu Fabra University (UPF)-Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
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17
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Patra SM, Chakraborty S, Shahane G, Prasanna X, Sengupta D, Maiti PK, Chattopadhyay A. Differential dynamics of the serotonin1A receptor in membrane bilayers of varying cholesterol content revealed by all atom molecular dynamics simulation. Mol Membr Biol 2016; 32:127-37. [PMID: 26508556 DOI: 10.3109/09687688.2015.1096971] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The serotonin1A receptor belongs to the superfamily of G protein-coupled receptors (GPCRs) and is a potential drug target in neuropsychiatric disorders. The receptor has been shown to require membrane cholesterol for its organization, dynamics and function. Although recent work suggests a close interaction of cholesterol with the receptor, the structural integrity of the serotonin1A receptor in the presence of cholesterol has not been explored. In this work, we have carried out all atom molecular dynamics simulations, totaling to 3 μs, to analyze the effect of cholesterol on the structure and dynamics of the serotonin1A receptor. Our results show that the presence of physiologically relevant concentration of membrane cholesterol alters conformational dynamics of the serotonin1A receptor and, on an average lowers conformational fluctuations. Our results show that, in general, transmembrane helix VII is most affected by the absence of membrane cholesterol. These results are in overall agreement with experimental data showing enhancement of GPCR stability in the presence of membrane cholesterol. Our results constitute a molecular level understanding of GPCR-cholesterol interaction, and represent an important step in our overall understanding of GPCR function in health and disease.
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Affiliation(s)
- Swarna M Patra
- a Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science , Bangalore , India .,b Department of Chemistry , RV College of Engineering , Bangalore , India
| | - Sudip Chakraborty
- a Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science , Bangalore , India
| | - Ganesh Shahane
- c CSIR-National Chemical Laboratory , Pune , India , and
| | | | - Durba Sengupta
- c CSIR-National Chemical Laboratory , Pune , India , and
| | - Prabal K Maiti
- a Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science , Bangalore , India
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18
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Roy S, Dasgupta A, Banerjee U, Chowdhury P, Mukhopadhyay A, Saha G, Singh O. Role of membrane cholesterol and lipid peroxidation in regulating the Na +/K +-ATPase activity in schizophrenia. Indian J Psychiatry 2016; 58:317-325. [PMID: 28066011 PMCID: PMC5100125 DOI: 10.4103/0019-5545.192023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Na+/K+-ATPase (NKA) activity is compromised in several neuropsychiatric disorders. Oxidative stress and membrane lipid composition play important roles in regulating NKA activity. AIMS The present study was undertaken to evaluate the effects of oxidative stress-induced membrane lipid damage and membrane cholesterol composition on NKA pump activity in schizophrenia. SETTINGS AND DESIGN It was a hospital-based, cross-sectional, observational study in 49 cases and 51 controls for 1 year. MATERIALS AND METHODS NKA pump activity in red blood cell membrane, serum levels of thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC) adducts, and cholesterol were measured by standard spectrophotometric techniques in newly diagnosed schizophrenia patients by Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criteria. Membrane cholesterol was analyzed by chloroform and isopropanol extraction followed by measuring the cholesterol concentration by spectrophotometric technique. STATISTICAL ANALYSIS AND RESULTS Mean values for NKA pump activity, membrane cholesterol level, and serum cholesterol levels were significantly lower in the case group (P < 0.001). The activity of NKA pump was found to be directly correlated to membrane cholesterol level rather than with the serum cholesterol values. Although the NKA pump activity showed inverse relationship with the serum values of TBARS and PC products both, on multiple linear regression analysis, it was found to be significantly positively dependent on the membrane cholesterol (β = 0.268, P = 0.01) and negatively dependent on the serum TBARS (β = -0.63, P < 0.001) levels only. CONCLUSION Reduced membrane cholesterol and oxidative stress-induced damage to membrane lipids play crucial roles in decreasing the NKA activity in schizophrenia. Hence, for a better prognosis and treatment, measures are required to maintain optimum levels of cholesterol in neuronal tissues along with a proper control on oxidative stress.
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Affiliation(s)
- Suparna Roy
- Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India
| | - Anindya Dasgupta
- Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India
| | - Ushasi Banerjee
- Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India; Department of Biochemistry, North Bengal Medical College, Susrutanagar, Darjeeling, West Bengal, India
| | - Piali Chowdhury
- Department of Biochemistry, Calcutta National Medical College, Kolkata, West Bengal, India
| | - Ashis Mukhopadhyay
- Department of Psychiatry, Calcutta National Medical College and Hospital, Kolkata, West Bengal, India
| | - Gautam Saha
- Consultant Psychiatrist and Director, Clinic Brain, Barasat, West Bengal, India
| | - Omprakash Singh
- Department of Psychiatry, NRS Medical College, Kolkata, West Bengal, India
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19
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Endeward V, Al-Samir S, Itel F, Gros G. How does carbon dioxide permeate cell membranes? A discussion of concepts, results and methods. Front Physiol 2014; 4:382. [PMID: 24409149 PMCID: PMC3884148 DOI: 10.3389/fphys.2013.00382] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 12/05/2013] [Indexed: 12/13/2022] Open
Abstract
We review briefly how the thinking about the permeation of gases, especially CO2, across cell and artificial lipid membranes has evolved during the last 100 years. We then describe how the recent finding of a drastic effect of cholesterol on CO2 permeability of both biological and artificial membranes fundamentally alters the long-standing idea that CO2—as well as other gases—permeates all membranes with great ease. This requires revision of the widely accepted paradigm that membranes never offer a serious diffusion resistance to CO2 or other gases. Earlier observations of “CO2-impermeable membranes” can now be explained by the high cholesterol content of some membranes. Thus, cholesterol is a membrane component that nature can use to adapt membrane CO2 permeability to the functional needs of the cell. Since cholesterol serves many other cellular functions, it cannot be reduced indefinitely. We show, however, that cells that possess a high metabolic rate and/or a high rate of O2 and CO2 exchange, do require very high CO2 permeabilities that may not be achievable merely by reduction of membrane cholesterol. The article then discusses the alternative possibility of raising the CO2 permeability of a membrane by incorporating protein CO2 channels. The highly controversial issue of gas and CO2 channels is systematically and critically reviewed. It is concluded that a majority of the results considered to be reliable, is in favor of the concept of existence and functional relevance of protein gas channels. The effect of intracellular carbonic anhydrase, which has recently been proposed as an alternative mechanism to a membrane CO2 channel, is analysed quantitatively and the idea considered untenable. After a brief review of the knowledge on permeation of O2 and NO through membranes, we present a summary of the 18O method used to measure the CO2 permeability of membranes and discuss quantitatively critical questions that may be addressed to this method.
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Affiliation(s)
- Volker Endeward
- Zentrum Physiologie, Vegetative Physiologie 4220, Medizinische Hochschule Hannover Hannover, Germany
| | - Samer Al-Samir
- Zentrum Physiologie, Vegetative Physiologie 4220, Medizinische Hochschule Hannover Hannover, Germany
| | - Fabian Itel
- Departement Chemie, Universität Basel Basel, Switzerland
| | - Gerolf Gros
- Zentrum Physiologie, Vegetative Physiologie 4220, Medizinische Hochschule Hannover Hannover, Germany
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20
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Zidovetzki R, Levitan I. Use of cyclodextrins to manipulate plasma membrane cholesterol content: evidence, misconceptions and control strategies. Biochim Biophys Acta 2007; 1768:1311-24. [PMID: 17493580 PMCID: PMC1948080 DOI: 10.1016/j.bbamem.2007.03.026] [Citation(s) in RCA: 799] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 03/12/2007] [Accepted: 03/15/2007] [Indexed: 12/14/2022]
Abstract
The physiological importance of cholesterol in the cell plasma membrane has attracted increased attention in recent years. Consequently, the use of methods of controlled manipulation of membrane cholesterol content has also increased sharply, especially as a method of studying putative cholesterol-enriched cell membrane domains (rafts). The most common means of modifying the cholesterol content of cell membranes is the incubation of cells or model membranes with cyclodextrins, a family of compounds, which, due to the presence of relatively hydrophobic cavity, can be used to extract cholesterol from cell membranes. However, the mechanism of this activity of cyclodextrins is not completely established. Moreover, under conditions commonly used for cholesterol extraction, cyclodextrins may remove cholesterol from both raft and non-raft domains of the membrane as well as alter the distribution of cholesterol between plasma and intracellular membranes. In addition, other hydrophobic molecules such as phospholipids may also be extracted from the membranes by cyclodextrins. We review the evidence for the specific and non-specific effects of cyclodextrins and what is known about the mechanisms for cyclodextrin-induced cholesterol and phospholipid extraction. Finally, we discuss useful control strategies that may help to verify that the observed effects are due specifically to cyclodextrin-induced changes in cellular cholesterol.
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Affiliation(s)
- Raphael Zidovetzki
- Department of Cell Biology and Neuroscience, University of California, Riverside, CA 90291, USA
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