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Krogman WL, Woodard T, McKay RSF. Anesthetic Mechanisms: Synergistic Interactions With Lipid Rafts and Voltage-Gated Sodium Channels. Anesth Analg 2024; 139:92-106. [PMID: 37968836 DOI: 10.1213/ane.0000000000006738] [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: 11/17/2023]
Abstract
Despite successfully utilizing anesthetics for over 150 years, the mechanism of action remains relatively unknown. Recent studies have shown promising results, but due to the complex interactions between anesthetics and their targets, there remains a clear need for further mechanistic research. We know that lipophilicity is directly connected to anesthetic potency since lipid solubility relates to anesthetic partition into the membrane. However, clinically relevant concentrations of anesthetics do not significantly affect lipid bilayers but continue to influence various molecular targets. Lipid rafts are derived from liquid-ordered phases of the plasma membrane that contain increased concentrations of cholesterol and sphingomyelin and act as staging platforms for membrane proteins, including ion channels. Although anesthetics do not perturb membranes at clinically relevant concentrations, they have recently been shown to target lipid rafts. In this review, we summarize current research on how different types of anesthetics-local, inhalational, and intravenous-bind and affect both lipid rafts and voltage-gated sodium channels, one of their major targets, and how those effects synergize to cause anesthesia and analgesia. Local anesthetics block voltage-gated sodium channel pores while also disrupting lipid packing in ordered membranes. Inhalational anesthetics bind to the channel pore and the voltage-sensing domain while causing an increase in the number, size, and diameter of lipid rafts. Intravenous anesthetics bind to the channel primarily at the voltage-sensing domain and the selectivity filter, while causing lipid raft perturbation. These changes in lipid nanodomain structure possibly give proteins access to substrates that have translocated as a result of these structural alterations, resulting in lipid-driven anesthesia. Overall, anesthetics can impact channel activity either through direct interaction with the channel, indirectly through the lipid raft, or both. Together, these result in decreased sodium ion flux into the cell, disrupting action potentials and producing anesthetic effects. However, more research is needed to elucidate the indirect mechanisms associated with channel disruption through the lipid raft, as not much is known about anionic lipid products and their influence over voltage-gated sodium channels. Anesthetics' effect on S-palmitoylation, a promising mechanism for direct and indirect influence over voltage-gated sodium channels, is another auspicious avenue of research. Understanding the mechanisms of different types of anesthetics will allow anesthesiologists greater flexibility and more specificity when treating patients.
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Affiliation(s)
- William L Krogman
- From the Department of Anesthesiology, University of Kansas School of Medicine - Wichita, Wichita, Kansas
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Alkafaas SS, Abdallah AM, Hassan MH, Hussien AM, Elkafas SS, Loutfy SA, Mikhail A, Murad OG, Elsalahaty MI, Hessien M, Elshazli RM, Alsaeed FA, Ahmed AE, Kamal HK, Hafez W, El-Saadony MT, El-Tarabily KA, Ghosh S. Molecular docking as a tool for the discovery of novel insight about the role of acid sphingomyelinase inhibitors in SARS- CoV-2 infectivity. BMC Public Health 2024; 24:395. [PMID: 38321448 PMCID: PMC10848368 DOI: 10.1186/s12889-024-17747-z] [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: 10/24/2023] [Accepted: 01/11/2024] [Indexed: 02/08/2024] Open
Abstract
Recently, COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants, caused > 6 million deaths. Symptoms included respiratory strain and complications, leading to severe pneumonia. SARS-CoV-2 attaches to the ACE-2 receptor of the host cell membrane to enter. Targeting the SARS-CoV-2 entry may effectively inhibit infection. Acid sphingomyelinase (ASMase) is a lysosomal protein that catalyzes the conversion of sphingolipid (sphingomyelin) to ceramide. Ceramide molecules aggregate/assemble on the plasma membrane to form "platforms" that facilitate the viral intake into the cell. Impairing the ASMase activity will eventually disrupt viral entry into the cell. In this review, we identified the metabolism of sphingolipids, sphingolipids' role in cell signal transduction cascades, and viral infection mechanisms. Also, we outlined ASMase structure and underlying mechanisms inhibiting viral entry 40 with the aid of inhibitors of acid sphingomyelinase (FIASMAs). In silico molecular docking analyses of FIASMAs with inhibitors revealed that dilazep (S = - 12.58 kcal/mol), emetine (S = - 11.65 kcal/mol), pimozide (S = - 11.29 kcal/mol), carvedilol (S = - 11.28 kcal/mol), mebeverine (S = - 11.14 kcal/mol), cepharanthine (S = - 11.06 kcal/mol), hydroxyzin (S = - 10.96 kcal/mol), astemizole (S = - 10.81 kcal/mol), sertindole (S = - 10.55 kcal/mol), and bepridil (S = - 10.47 kcal/mol) have higher inhibition activity than the candidate drug amiodarone (S = - 10.43 kcal/mol), making them better options for inhibition.
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Affiliation(s)
- Samar Sami Alkafaas
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
| | - Abanoub Mosaad Abdallah
- Narcotic Research Department, National Center for Social and Criminological Research (NCSCR), Giza, 11561, Egypt
| | - Mai H Hassan
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Aya Misbah Hussien
- Biotechnology department at Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
| | - Sara Samy Elkafas
- Production Engineering and Mechanical Design Department, Faculty of Engineering, Menofia University, Menofia, Egypt
- Faculty of Control System and Robotics, ITMO University, Saint-Petersburg, 197101, Russia
| | - Samah A Loutfy
- Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- Nanotechnology Research Center, British University, Cairo, Egypt
| | - Abanoub Mikhail
- Department of Physics, Faculty of Science, Minia University, Minia, Egypt
- Faculty of Physics, ITMO University, Saint Petersburg, Russia
| | - Omnia G Murad
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Mohamed I Elsalahaty
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Mohamed Hessien
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Rami M Elshazli
- Biochemistry and Molecular Genetics Unit, Department of Basic Sciences, Faculty of Physical Therapy, Horus University - Egypt, New Damietta, 34517, Egypt
| | - Fatimah A Alsaeed
- Department of Biology, College of Science, King Khalid University, Muhayl, Saudi Arabia
| | - Ahmed Ezzat Ahmed
- Biology Department, College of Science, King Khalid University, Abha, 61413, Saudi Arabia
| | - Hani K Kamal
- Anatomy and Histology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Wael Hafez
- NMC Royal Hospital, 16Th Street, 35233, Khalifa City, Abu Dhabi, United Arab Emirates
- Medical Research Division, Department of Internal Medicine, The National Research Centre, 12622, 33 El Buhouth St, Ad Doqi, Dokki, Cairo Governorate, Egypt
| | - Mohamed T El-Saadony
- Department of Agricultural Microbiology, Faculty of Agriculture, Zagazig University, Zagazig, 44511, Egypt
| | - Khaled A El-Tarabily
- Department of Biology, College of Science, United Arab Emirates University, Al-Ain, 15551, United Arab Emirates
| | - Soumya Ghosh
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, 9301, South Africa
- Natural & Medical Science Research Center, University of Nizwa, Nizwa, Oman
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3
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Intravital Ca2+ imaging of pancreatic β cell function after bariatric surgery. Cell Calcium 2022; 104:102566. [DOI: 10.1016/j.ceca.2022.102566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/22/2022] [Indexed: 11/24/2022]
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Interaction of drugs with lipid raft membrane domains as a possible target. Drug Target Insights 2021; 14:34-47. [PMID: 33510571 PMCID: PMC7832984 DOI: 10.33393/dti.2020.2185] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/11/2020] [Indexed: 01/23/2023] Open
Abstract
Introduction Plasma membranes are not the homogeneous bilayers of uniformly distributed lipids but the lipid complex with laterally separated lipid raft membrane domains, which provide receptor, ion channel and enzyme proteins with a platform. The aim of this article is to review the mechanistic interaction of drugs with membrane lipid rafts and address the question whether drugs induce physicochemical changes in raft-constituting and raft-surrounding membranes. Methods Literature searches of PubMed/MEDLINE and Google Scholar databases from 2000 to 2020 were conducted to include articles published in English in internationally recognized journals. Collected articles were independently reviewed by title, abstract and text for relevance. Results The literature search indicated that pharmacologically diverse drugs interact with raft model membranes and cellular membrane lipid rafts. They could physicochemically modify functional protein-localizing membrane lipid rafts and the membranes surrounding such domains, affecting the raft organizational integrity with the resultant exhibition of pharmacological activity. Raft-acting drugs were characterized as ones to decrease membrane fluidity, induce liquid-ordered phase or order plasma membranes, leading to lipid raft formation; and ones to increase membrane fluidity, induce liquid-disordered phase or reduce phase transition temperature, leading to lipid raft disruption. Conclusion Targeting lipid raft membrane domains would open a new way for drug design and development. Since angiotensin-converting enzyme 2 receptors which are a cell-specific target of and responsible for the cellular entry of novel coronavirus are localized in lipid rafts, agents that specifically disrupt the relevant rafts may be a drug against coronavirus disease 2019.
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Affiliation(s)
- Steven L. Regen
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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Lotierzo MCG, Casadei BR, de Castro RD, Malheiros B, Barbosa LRS. Cubic-to-inverted micellar and the cubic-to-hexagonal-to-micellar transitions on phytantriol-based cubosomes induced by solvents. Drug Deliv Transl Res 2020; 10:1571-1583. [PMID: 32783155 DOI: 10.1007/s13346-020-00828-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cubosomes are nanoparticles composed of a specific combination of some types of amphiphilic molecules like lipids, such as phytantriol (PHY), and a nonionic polymer, like poloxamer (F127). Cubosomes have a high hydrophobic volume (> 50%) and are good candidates for drug delivery systems. Due to their unique structure, these nanoparticles possess the ability to incorporate highly hydrophobic drugs. A challenge for the encapsulation of hydrophobic molecules is the use of organic solvents in the sample preparation process. In this study, we investigated the structural influence of four different solvents (acetone, ethanol, chloroform, and octane), by means of small-angle X-ray scattering and cryogenic electron microscopy techniques. In the presence of a high amount of acetone and ethanol (1:5 solvent:PHY volumetric ratio), for instance, a cubic-to-micellar phase transition was observed due to the high presence of these two solvents. Chloroform and octane have different effects over PHY-based cubosomes as compared to acetone and ethanol, both of them induced a cubic-to-inverse hexagonal phase transition. Those effects are attributed to the insertion of the solvent in the hydrophobic region of the cubosomes, increasing its volume and inducing such transition. Moreover, a second phase transition from reversed hexagonal-to-inverted micellar was observed for chloroform and octane. The data also suggest that after 24 h of solvent/cubosome incubation, some structural features of cubosomes change as compared to the freshly prepared samples. This study could shed light on drug delivery systems using PHY-based cubosomes to choose the appropriate solvent in order to load the drug into the cubosome.Graphical abstract.
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Affiliation(s)
- Mayra C G Lotierzo
- Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Av. Prof. Lineu Prestes n 580 Bloco 16, São Paulo, SP, 05508-000, Brazil
| | - Bruna R Casadei
- Institute of Physics, University of São Paulo, Rua do Matão, 1371, São Paulo, 05508-090, Brazil
| | - Raphael Dias de Castro
- Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Av. Prof. Lineu Prestes n 580 Bloco 16, São Paulo, SP, 05508-000, Brazil.,Institute of Physics, University of São Paulo, Rua do Matão, 1371, São Paulo, 05508-090, Brazil
| | - Barbara Malheiros
- Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Av. Prof. Lineu Prestes n 580 Bloco 16, São Paulo, SP, 05508-000, Brazil
| | - Leandro R S Barbosa
- Department of Biochemical and Pharmaceutical Technology, University of São Paulo, Av. Prof. Lineu Prestes n 580 Bloco 16, São Paulo, SP, 05508-000, Brazil. .,Institute of Physics, University of São Paulo, Rua do Matão, 1371, São Paulo, 05508-090, Brazil.
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7
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Jacob S, Köhler M, Tröster P, Visa M, García-Prieto CF, Alanentalo T, Moede T, Leibiger B, Leibiger IB, Berggren PO. In vivo Ca 2+ dynamics in single pancreatic β cells. FASEB J 2019; 34:945-959. [PMID: 31914664 DOI: 10.1096/fj.201901302rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/25/2019] [Accepted: 11/05/2019] [Indexed: 11/11/2022]
Abstract
The dynamics of cytoplasmic free Ca2+ concentration ([Ca2+]i) in pancreatic β cells is central to our understanding of β-cell physiology and pathology. In this context, there are numerous in vitro studies available but existing in vivo data are scarce. We now critically evaluate the anterior chamber of the eye as an in vivo, non-invasive, imaging site for measuring [Ca2+]i dynamics longitudinally in three dimensions and at single-cell resolution. By applying a fluorescently labeled glucose analogue 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose in vivo, we followed how glucose almost simultaneously distributes to all cells within the islet volume, resulting in [Ca2+]i changes. We found that almost all β cells in healthy mice responded to a glucose challenge, while in hyperinsulinemic, hyperglycemic mice about 80% of the β cells could not be further stimulated from fasting basal conditions. This finding indicates that our imaging modality can resolve functional heterogeneity within the β-cell population in terms of glucose responsiveness. Importantly, we demonstrate that glucose homeostasis is markedly affected using isoflurane compared to hypnorm/midazolam anesthetics, which has major implications for [Ca2+]i measurements. In summary, this setup offers a powerful tool to further investigate in vivo pancreatic β-cell [Ca2+]i response patterns at single-cell resolution in health and disease.
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Affiliation(s)
- Stefan Jacob
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Martin Köhler
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Philip Tröster
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Montse Visa
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Concha F García-Prieto
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Tomas Alanentalo
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Tilo Moede
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Barbara Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Ingo B Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
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8
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Almeida PF. How to Determine Lipid Interactions in Membranes from Experiment Through the Ising Model. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:21-40. [PMID: 30589556 DOI: 10.1021/acs.langmuir.8b03054] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The determination and the meaning of interactions in lipid bilayers are discussed and interpreted through the Ising model. Originally developed to understand phase transitions in ferromagnetic systems, the Ising model applies equally well to lipid bilayers. In the case of a membrane, the essence of the Ising model is that each lipid is represented by a site on a lattice and that the interaction of each site with its nearest neighbors is represented by an energy parameter ω. To calculate the thermodynamic properties of the system, such as the enthalpy, the Gibbs energy, and the heat capacity, the partition function is derived. The calculation of the configurational entropy factor in the partition function, however, requires approximations or the use of Monte Carlo (MC) simulations. Those approximations are described. Ultimately, MC simulations are used in combination with experiment to determine the interaction parameters ω in lipid bilayers. Several experimental approaches are described, which can be used to obtain interaction parameters. They include nearest-neighbor recognition, differential scanning calorimetry, and Förster resonance energy transfer. Those approaches are most powerful when used in combination of MC simulations of Ising models. Lipid membranes of different compositions are discussed, which have been studied with these approaches. They include mixtures of cholesterol, saturated (ordered) phospholipids, and unsaturated (disordered) phospholipids. The interactions between those lipid species are examined as a function of molecular properties such as the degree of unsaturation and the acyl chain length. The general rule that emerges is that interactions between different lipids are usually unfavorable. The exception is that cholesterol interacts favorably with saturated (ordered) phospholipids. However, the interaction of cholesterol with unsaturated phospholipids becomes extremely unfavorable as the degree of unsaturation increases.
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Affiliation(s)
- Paulo F Almeida
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
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Wang C, Almeida PF, Regen SL. Net Interactions That Push Cholesterol Away from Unsaturated Phospholipids Are Driven by Enthalpy. Biochemistry 2018; 57:6637-6643. [DOI: 10.1021/acs.biochem.8b00983] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chang Wang
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Paulo F. Almeida
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28403, United States
| | - Steven L. Regen
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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10
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Almeida PF, Carter FE, Kilgour KM, Raymonda MH, Tejada E. Heat Capacity of DPPC/Cholesterol Mixtures: Comparison of Single Bilayers with Multibilayers and Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:9798-9809. [PMID: 30088940 DOI: 10.1021/acs.langmuir.8b01774] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The excess heat capacity (Δ C p) of mixtures of dipalmitoylphosphatidylcholine (DPPC) and cholesterol (Chol) is examined in detail in large unilamellar vesicles (LUVs), both experimentally, using differential scanning calorimetry (DSC), and theoretically, using a three-state Ising model. The model postulates that DPPC can access three conformational states: gel, liquid-disordered (Ld), and liquid-ordered (Lo). The Lo state, however, is only available if coupled with interaction with an adjacent Chol. Δ C p was calculated using Monte Carlo simulations on a lattice and compared to experiment. The DSC results in LUVs are compared with literature data on multilamellar vesicles (MLVs). The enthalpy change of the complete phase transition from gel to Ld is identical in LUVs and MLVs, and the melting temperatures ( Tm) are similar. However, the DSC curves in LUVs are significantly broader, and the maxima of Δ C p are accordingly smaller. The parameters in the Ising model were chosen to match the DSC curves in LUVs and the nearest-neighbor recognition (NNR) data. The model reproduces the NNR data very well. It also reproduces the phase transition in DPPC, the freezing point depression induced by Chol, and the broad component of Δ C p in DPPC/Chol LUVs. However, there is a sharp component, between 5 and 15 mol % Chol, that the model does not reproduce. The broad component of Δ C p becomes dominant as Chol concentration increases, indicating that it involves melting of the Lo phase. Because the simulations reproduce this component, the conclusions regarding the nature of the phase transition at high Chol concentrations and the structure of the Lo phase are important: there is no true phase separation in DPPC/Chol LUVs. There are large domains of gel and Lo phase coexisting below Tm of DPPC, but above Tm the three states of DPPC are mixed with Chol, although clusters persist.
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Affiliation(s)
- Paulo F Almeida
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Faith E Carter
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Katie M Kilgour
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Matthew H Raymonda
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
| | - Emmanuel Tejada
- Department of Chemistry and Biochemistry , University of North Carolina Wilmington , Wilmington , North Carolina 28403 , United States
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11
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Borsacchi S, Geppi M, Macchi S, Ninham BW, Fratini E, Ambrosi M, Baglioni P, Lo Nostro P. Phase transitions in hydrophobe/phospholipid mixtures: hints at connections between pheromones and anaesthetic activity. Phys Chem Chem Phys 2018; 18:15375-83. [PMID: 27210443 DOI: 10.1039/c6cp00659k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The phase behavior of a mixture of a typical insect pheromone (olean) and a phospholipid (DOPC)/water dispersion is extensively explored through SAXS, NMR and DSC experiments. The results mimic those obtained with anaesthetics in phospholipid/water systems. They also mimic the behavior and microstructure of ternary mixtures of a membrane mimetic, bilayer-forming double chained surfactants, oils and water. Taken together with recent models for conduction of the nervous impulse, all hint at lipid involvement and the underlying unity in mechanisms of pheromone, anaesthetic and hydrophobic drugs, where a local phase change in the lipid membrane architecture may be at least partly involved in the transmission of the signal.
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Affiliation(s)
- Silvia Borsacchi
- Istituto di Chimica dei Composti OrganoMetallici (ICCOM) del CNR, 56124 Pisa, Italy
| | - Marco Geppi
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124 Pisa, Italy
| | - Sara Macchi
- Department of Chemistry and Industrial Chemistry, University of Pisa, 56124 Pisa, Italy
| | - Barry W Ninham
- Department of Chemistry & CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy. and Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia
| | - Emiliano Fratini
- Department of Chemistry & CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy.
| | - Moira Ambrosi
- Department of Chemistry & CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy.
| | - Piero Baglioni
- Department of Chemistry & CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy. and Enzo Ferroni Foundation, 50019 Sesto Fiorentino (Firenze), Italy
| | - Pierandrea Lo Nostro
- Department of Chemistry & CSGI, University of Florence, 50019 Sesto Fiorentino (Firenze), Italy. and Enzo Ferroni Foundation, 50019 Sesto Fiorentino (Firenze), Italy
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12
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Ninham BW, Larsson K, Lo Nostro P. Two sides of the coin. Part 2. Colloid and surface science meets real biointerfaces. Colloids Surf B Biointerfaces 2017; 159:394-404. [PMID: 28822288 DOI: 10.1016/j.colsurfb.2017.07.090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/07/2017] [Accepted: 07/31/2017] [Indexed: 12/23/2022]
Abstract
Part 1 revisited developments in lipid and surfactant self assembly over the past 40 years [1]. New concepts emerged. Here we explore how these developments can be used to make sense of and bring order to a range of complex biological phenomena. Together with Part 1, this contribution is a fundamental revision of intuition at the boundaries of Colloid Science and Biological interfaces from a perspective of nearly 50 years. We offer new insights on a unified treatment of self assembly of lipids, surfactants and proteins in the light of developments presented in Part 1. These were in the enabling disciplines in molecular forces, hydration, oil and electrolyte specificity; and in the role of non Euclidean geometries-across the whole gammut of physical, colloid and surface chemistry, biophysics and membrane biology and medicine. It is where the early founders of the cell theory of biology and the physiologists expected advances to occur as D'Arcy Thompson predicted us 100 years ago.
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Affiliation(s)
- Barry W Ninham
- Department of Applied Mathematics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200, Australia; Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Firenze, Italy
| | - Kåre Larsson
- Camurus Lipid Research Foundation, Ideon Science Park, 22370 Lund, Sweden
| | - Pierandrea Lo Nostro
- Department of Chemistry "Ugo Schiff", University of Florence, 50019 Sesto Fiorentino, Firenze, Italy; Fondazione Prof. Enzo Ferroni-Onlus, 50019 Sesto Fiorentino, Firenze, Italy.
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13
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A combined X-ray scattering and simulation study of halothane in membranes at raised pressures. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2016.12.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Yang J, Martí J, Calero C. Pair interactions among ternary DPPC/POPC/cholesterol mixtures in liquid-ordered and liquid-disordered phases. SOFT MATTER 2016; 12:4557-4561. [PMID: 27103534 DOI: 10.1039/c6sm00345a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Saturated phospholipids, unsaturated phospholipids, and cholesterol are essential components of cell membranes, making the understanding of their mutual interactions of great significance. We have performed microsecond molecular dynamics simulations on the ternary mixtures of DPPC/POPC/cholesterol to systematically examine lipid-lipid and cholesterol-lipid interactions in the liquid-ordered and the liquid-disordered phases. The results show that there exists a competition between the tighter packing of cholesterol-lipid and the looser packing of lipid-lipid as the membrane changes from the liquid-disordered phase to the liquid-ordered phase. Depending on the lipid saturation, the favor of lipid-lipid interactions is in the order of saturated-saturated > monounsaturated-monounsaturated > saturated-monounsaturated. Cholesterol-saturated lipid interactions are more favorable than cholesterol-monounsaturated lipid ones. The results are consistent with the push-pull forces derived from experiments and give general insights into the interactions among membrane components.
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Affiliation(s)
- Jing Yang
- Department of Physics, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain.
| | - Jordi Martí
- Department of Physics, Technical University of Catalonia-Barcelona Tech, B4-B5 Northern Campus, Jordi Girona 1-3, 08034 Barcelona, Catalonia, Spain.
| | - Carles Calero
- Center for Polymer Studies and Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA.
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Mukai M, Regen SL. Exchangeable Mimics of DPPC and DPPG Exhibiting Similar Nearest-Neighbor Interactions in Fluid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12674-12678. [PMID: 26536166 DOI: 10.1021/acs.langmuir.5b03174] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The interactions between an exchangeable mimic of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), Phos(±), with an exchangeable mimic of cholesterol, Chol, have been analyzed in fluid bilayers by means of nearest-neighbor recognition measurements. These interactions have been found to be very similar to those of an exchangeable mimic of 1,2-dipalmitoyl-sn-glycerol-3-phospho-(1'rac-glycerol) (DPPG), Phos(-), interacting with Chol. Thus, both phospholipids have a similar preference for becoming nearest-neighbors of Chol in the liquid-ordered (l0) phase, and both mix, ideally, with Chol in the liquid-disordered (ld) phase. These findings, together with the almost negligible screening effects found for the latter, provide strong evidence that electrostatic forces play a minor role in the preference that both phospholipids have in becoming a favored nearest-neighbor of Chol. They also imply that the main driving force for forming the liquid-ordered phase, and for defining the lateral organization of this phase, is an intrinsic affinity that high-melting lipids and cholesterol have for each other.
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Affiliation(s)
- Masaru Mukai
- Department of Chemistry, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | - Steven L Regen
- Department of Chemistry, Lehigh University , Bethlehem, Pennsylvania 18015, United States
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16
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Wang C, Krause MR, Regen SL. Push and pull forces in lipid raft formation: the push can be as important as the pull. J Am Chem Soc 2015; 137:664-6. [PMID: 25561007 DOI: 10.1021/ja5115437] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nearest-neighbor recognition measurements have been made using exchangeable mimics of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine in the liquid-ordered (lo) and liquid-disordered (ld) states. In the ld phase, the net interaction between these two lipids is repulsive. In the lo phase, their interactions are neither attractive nor repulsive. These results, together with previous nearest-neighbor measurements, imply that the overall driving force for lipid domain formation in bilayers composed of high-melting lipids, low-melting lipids, and cholesterol, corresponds to a strong pull (attraction) between the high-melting lipids and cholesterol, a significant push (repulsion) between the low-melting and high-melting lipids, and a significant push between the low-melting lipids and cholesterol. In a broader context, these results provide strong support for the notion that repulsive forces play a major role in the formation of lipid rafts.
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Affiliation(s)
- Chang Wang
- Department of Chemistry, Lehigh University , Bethlehem, Pennsylvania 18015, United States
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17
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Krause MR, Regen SL. The structural role of cholesterol in cell membranes: from condensed bilayers to lipid rafts. Acc Chem Res 2014; 47:3512-21. [PMID: 25310179 DOI: 10.1021/ar500260t] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONSPECTUS: Defining the two-dimensional structure of cell membranes represents one of the most daunting challenges currently facing chemists, biochemists, and biophysicists. In particular, the time-averaged lateral organization of the lipids and proteins that make up these natural enclosures has yet to be established. As the classic Singer-Nicolson model of cell membranes has evolved over the past 40 years, special attention has focused on the structural role played by cholesterol, a key component that represents ca. 30% of the total lipids that are present. Despite extensive studies with model membranes, two fundamental issues have remained a mystery: (i) the mechanism by which cholesterol condenses low-melting lipids by uncoiling their acyl chains and (ii) the thermodynamics of the interaction between cholesterol and high- and low-melting lipids. The latter bears directly on one of the most popular notions in modern cell biology, that is, the lipid raft hypothesis, whereby cholesterol is thought to combine with high-melting lipids to form "lipid rafts" that float in a "sea" of low-melting lipids. In this Account, we first describe a chemical approach that we have developed in our laboratories that has allowed us to quantify the interactions between exchangeable mimics of cholesterol and low- and high-melting lipids in model membranes. In essence, this "nearest-neighbor recognition" (NNR) method involves the synthesis of dimeric forms of these lipids that contain a disulfide moiety as a linker. By means of thiolate-disulfide interchange reactions, equilibrium mixtures of dimers are then formed. These exchange reactions are initiated either by adding dithiothreitol to a liposomal dispersion to generate a small amount of thiol monomer or by including a small amount of thiol monomer in the liposomes at pH 5.0 and then raising the pH to 7.4. We then show how such NNR measurements have allowed us to distinguish between two very different mechanisms that have been proposed for cholesterol's condensing effect: (i) an umbrella mechanism in which the acyl chains and cholesterol become more tightly packed as cholesterol content increases because they share limited space under phospholipid headgroups and (ii) a template mechanism whereby cholesterol functions as a planar hydrophobic template at the membrane surface, thereby maximizing hydrophobic interactions and the hydrophobic effect. Specifically, our NNR experiments rule out the umbrella mechanism and provide strong support for the template mechanism. Similar NNR measurements have also allowed us to address the question of whether the interactions between low-melting kinked phospholipids and cholesterol can play a significant role in the formation of lipid rafts. Specifically, these NNR measurements have led to our discovery of a new physical principle in the lipids and membranes area that must be operating in biological membranes, that is, a "push-pull" mechanism, whereby cholesterol is pushed away from low-melting phospholipids and pulled toward high-melting lipids. Thus, to the extent that lipid rafts play a role in the functioning of cell membranes, low-melting phospholipids must be active participants.
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Affiliation(s)
- Martin R. Krause
- Department
of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Steven L. Regen
- Department
of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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18
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Krause M, Wang M, Mydock-McGrane L, Covey DF, Tejada E, Almeida PF, Regen SL. Eliminating the roughness in cholesterol's β-face: does it matter? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:12114-12118. [PMID: 25290635 PMCID: PMC4204922 DOI: 10.1021/la503075e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/06/2014] [Indexed: 06/03/2023]
Abstract
One of the long-standing issues surrounding cholesterol (Chol) relates to its two-faced character. In particular, the consequences of its having a rough β-face and a smooth α-face on its structural influence in cell membranes has remained elusive. In this study, direct comparisons have been made between cholesterol and a "smoothened" analog, DChol (i.e., 18,19-dinorcholesterol) using model membranes and a combination of nearest-neighbor recognition, differential scanning calorimetry, fluorescence, and monolayer measurements. Taken together, these results indicate that subtle differences exist between the interaction of these two sterols with the different states of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Chol has a greater condensing power than DChol, but only slightly so, i.e., on the order of a few tens of calories per mole.
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Affiliation(s)
- Martin
R. Krause
- Department
of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Minghui Wang
- Department
of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Laurel Mydock-McGrane
- Department
of Developmental Biology, Washington University
School of Medicine, St. Louis, Missouri 63110, United States
| | - Douglas F. Covey
- Department
of Developmental Biology, Washington University
School of Medicine, St. Louis, Missouri 63110, United States
- Departments
of Anesthesiology and Psychiatry and the Taylor Family Institute for
Innovative Psychiatric Research, Washington
University School of Medicine, St. Louis, Missouri 63110, United States
| | - Emmanuel Tejada
- Department
of Chemistry and Biochemistry, University
of North Carolina at Wilmington, Wilmington, North Carolina 28403, United States
| | - Paulo F. Almeida
- Department
of Chemistry and Biochemistry, University
of North Carolina at Wilmington, Wilmington, North Carolina 28403, United States
| | - Steven L. Regen
- Department
of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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Krause MR, Daly TA, Almeida PF, Regen SL. Push-pull mechanism for lipid raft formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:3285-3289. [PMID: 24621400 DOI: 10.1021/la500510s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A quantitative assessment has been made of the interaction between exchangeable mimics of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol in the liquid-ordered (l0) and the liquid-disordered (ld) states using the nearest-neighbor recognition (NNR) method. This assessment has established that these lipids mix ideally in the l0 phase (i.e., they show no net attraction or repulsion toward each other) but exhibit repulsive interactions in the ld phase. The implications of these findings for the interactions between unsaturated phospholipids and cholesterol in eukaryotic cell membranes are briefly discussed.
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Affiliation(s)
- Martin R Krause
- Department of Chemistry, Lehigh University , Bethlehem, Pennsylvania 18015, United States
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20
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Wilson A, Gasparini G, Matile S. Functional systems with orthogonal dynamic covalent bonds. Chem Soc Rev 2014; 43:1948-62. [DOI: 10.1039/c3cs60342c] [Citation(s) in RCA: 229] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Weinrich M, Worcester DL. Xenon and other volatile anesthetics change domain structure in model lipid raft membranes. J Phys Chem B 2013; 117:16141-7. [PMID: 24299622 DOI: 10.1021/jp411261g] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Inhalation anesthetics have been in clinical use for over 160 years, but the molecular mechanisms of action continue to be investigated. Direct interactions with ion channels received much attention after it was found that anesthetics do not change the structure of homogeneous model membranes. However, it was recently found that halothane, a prototypical anesthetic, changes domain structure of a binary lipid membrane. The noble gas xenon is an excellent anesthetic and provides a pivotal test of the generality of this finding, extended to ternary lipid raft mixtures. We report that xenon and conventional anesthetics change the domain equilibrium in two canonical ternary lipid raft mixtures. These findings demonstrate a membrane-mediated mechanism whereby inhalation anesthetics can affect the lipid environment of transmembrane proteins.
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Affiliation(s)
- Michael Weinrich
- Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda, Maryland 20892, United States
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Carmine A, Domoto Y, Sakai N, Matile S. Comparison of lipoic and asparagusic acid for surface-initiated disulfide-exchange polymerization. Chemistry 2013; 19:11558-63. [PMID: 23893874 DOI: 10.1002/chem.201301567] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Indexed: 01/06/2023]
Abstract
Bring it on: Organic chemistry on surfaces and in solution is not the same; this study offers a perfect example that small changes (from 27 to 35°; see graphic) can result in big consequences. Strained cyclic disulfides from asparagusic, but not lipoic acid, are ideal for growing functional architectures directly on surfaces; for the substrate-initiated synthesis of cell-penetrating poly(disulfide)s in solution, exactly the contrary is true.
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Affiliation(s)
- Alessio Carmine
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
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23
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Raju SG, Barber AF, LeBard DN, Klein ML, Carnevale V. Exploring volatile general anesthetic binding to a closed membrane-bound bacterial voltage-gated sodium channel via computation. PLoS Comput Biol 2013; 9:e1003090. [PMID: 23785267 PMCID: PMC3681623 DOI: 10.1371/journal.pcbi.1003090] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/26/2013] [Indexed: 01/07/2023] Open
Abstract
Despite the clinical ubiquity of anesthesia, the molecular basis of anesthetic action is poorly understood. Amongst the many molecular targets proposed to contribute to anesthetic effects, the voltage gated sodium channels (VGSCs) should also be considered relevant, as they have been shown to be sensitive to all general anesthetics tested thus far. However, binding sites for VGSCs have not been identified. Moreover, the mechanism of inhibition is still largely unknown. The recently reported atomic structures of several members of the bacterial VGSC family offer the opportunity to shed light on the mechanism of action of anesthetics on these important ion channels. To this end, we have performed a molecular dynamics "flooding" simulation on a membrane-bound structural model of the archetypal bacterial VGSC, NaChBac in a closed pore conformation. This computation allowed us to identify binding sites and access pathways for the commonly used volatile general anesthetic, isoflurane. Three sites have been characterized with binding affinities in a physiologically relevant range. Interestingly, one of the most favorable sites is in the pore of the channel, suggesting that the binding sites of local and general anesthetics may overlap. Surprisingly, even though the activation gate of the channel is closed, and therefore the pore and the aqueous compartment at the intracellular side are disconnected, we observe binding of isoflurane in the central cavity. Several sampled association and dissociation events in the central cavity provide consistent support to the hypothesis that the "fenestrations" present in the membrane-embedded region of the channel act as the long-hypothesized hydrophobic drug access pathway.
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Affiliation(s)
- S. G. Raju
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Annika F. Barber
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - David N. LeBard
- Department of Chemistry, Yeshiva University, New York, New York, United States of America
| | - Michael L. Klein
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania, United States of America
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Weinrich M, Nanda H, Worcester DL, Majkrzak CF, Maranville BB, Bezrukov SM. Halothane changes the domain structure of a binary lipid membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4723-8. [PMID: 22352350 PMCID: PMC3302933 DOI: 10.1021/la204317k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
X-ray and neutron diffraction studies of a binary lipid membrane demonstrate that halothane at physiological concentrations produces a pronounced redistribution of lipids between domains of different lipid types identified by different lamellar d-spacings and isotope composition. In contrast, dichlorohexafluorocyclobutane (F6), a halogenated nonanesthetic, does not produce such significant effects. These findings demonstrate a specific effect of inhalational anesthetics on mixing phase equilibria of a lipid mixture.
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Affiliation(s)
- Michael Weinrich
- National Center for Medical Rehabilitation Research, Eunice Kennedy Shriver Institute of Child Health and Human Development, Bethesda, Maryland, United States.
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