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da Cunha AR, Duarte EL, Vignoli Muniz GS, Coutinho K, Lamy MT. New insights into the interaction of emodin with lipid membranes. Biophys Chem 2024; 309:107233. [PMID: 38579435 DOI: 10.1016/j.bpc.2024.107233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/26/2024] [Accepted: 04/01/2024] [Indexed: 04/07/2024]
Abstract
Emodin is a natural anthraquinone derivative found in nature, widely known as an herbal medicine. Here, the partition, location, and interaction of emodin with lipid membranes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are experimentally investigated with different techniques. Our studies have considered the neutral form of emodin (EMH) and its anionic/deprotonated form (EM-), and their interaction with a more and less packed lipid membrane, DMPC at the gel and fluid phases, respectively. Though DSC results indicate that the two species, EMH and EM-, similarly disrupt the packing of DMPC bilayers, spin labels clearly show that EMH causes a stronger bilayer disruption, both in gel and fluid DMPC. Fluorescence spectroscopy shows that both EMH and EM- have a high affinity for DMPC: the binding of EM- to both gel and fluid DMPC bilayers was found to be quite similar, and similar to that of EMH to gel DMPC, Kp = (1.4 ± 0.3)x103. However, EMH was found to bind twice more strongly to fluid DMPC bilayers, Kp = (3.2 ± 0.3)x103. Spin labels and optical absorption spectroscopy indicate that emodin is located close to the lipid bilayer surface, and suggest that EM- is closer to the lipid/water interface than EMH, as expected. The present studies present a relevant contribution to the current understanding of the effect the two species of emodin, EMH and EM-, present on different microregions of an organism, as local pH values can vary significantly, can cause in a neutral lipid membrane, either more or less packed, liked gel and fluid DMPC, respectively, and could be extended to lipid domains of biological membranes.
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Affiliation(s)
- Antonio R da Cunha
- Universidade Federal do Maranhão, UFMA, Campus Balsas, 65800-000, Maranhão, Brazil; Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil.
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
| | - Gabriel S Vignoli Muniz
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil; Instituto de Química, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Brasília 70910-900, Brazil
| | - Kaline Coutinho
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Cidade Universitária, São Paulo 05508-090, Brazil
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2
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Ejarque JB, Duarte EL, Lamy MT, Rozenfeld JHK. Evidence for Ca 2+-induced structural change in diluted GD3 ganglioside dispersions. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184271. [PMID: 38199327 DOI: 10.1016/j.bbamem.2024.184271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/02/2024] [Accepted: 01/04/2024] [Indexed: 01/12/2024]
Affiliation(s)
- Julia B Ejarque
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508-090 São Paulo, SP, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508-090 São Paulo, SP, Brazil
| | - Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil.
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Martins LS, Duarte EL, Lamy MT, Rozenfeld JHK. DODAB vesicles containing lysophosphatidylcholines: The relevance of acyl chain saturation on the membrane structure and thermal properties. Biophys Chem 2023; 300:107075. [PMID: 37451052 DOI: 10.1016/j.bpc.2023.107075] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/28/2023] [Accepted: 07/02/2023] [Indexed: 07/18/2023]
Abstract
The saturated LPC18:0 and unsaturated LPC18:1 lysophosphatidylcholines have important roles in inflammation and immunity and are interesting targets for immunotherapy. The synthetic cationic lipid DODAB has been successfully employed in delivery systems, and would be a suitable carrier for those lysophosphatidylcholines. Here, assemblies of DODAB and LPC18:0 or LPC18:1 were characterized by Differential Scanning Calorimetry (DSC) and Electron Paramagnetic Resonance (EPR) spectroscopy. LPC18:0 increased the DODAB gel-fluid transition enthalpy and rigidified both phases. In contrast, LPC18:1 caused a decrease in the DODAB gel-fluid transition temperature and cooperativity, associated with two populations with distinct rigidities in the gel phase. In the fluid phase, LPC18:1 increased the surface order but, differently from LPC18:0, did not affect viscosity at the membrane core. The impact of the different acyl chains of LPC18:0 and 18:1 on structure and thermotropic behavior should be considered when developing applications using mixed DODAB membranes.
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Affiliation(s)
- Letícia S Martins
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, SP 04023-062, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, São Paulo, SP 05508-090, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, São Paulo, SP 05508-090, Brazil
| | - Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, São Paulo, SP 04023-062, Brazil.
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de Andrade L, Duarte EL, Lamy MT, Rozenfeld JHK. Thermotropic Behavior and Structural Organization of C24:1 Sulfatide Dispersions and Its Mixtures with Cationic Bilayers. ACS OMEGA 2023; 8:5306-5315. [PMID: 36816677 PMCID: PMC9933474 DOI: 10.1021/acsomega.2c06189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
C24:1 sulfatide (SF) is an endogenous activator of type II NKT cells. The thermotropic behavior and structure of SF dispersions and its mixtures (4.8-16.6 mol %) with cationic dioctadecyldimethylammonium bromide (DODAB) bilayers were investigated by differential scanning calorimetry and electron paramagnetic resonance spectroscopy. The non-interdigitated lamellar structures formed by pure SF display broad thermal events around 27.5 °C when heated and cooled. These events disappear upon mixing with DODAB, showing complete lipid miscibility. SF decreases the DODAB gel-phase packing, with a consequent decrease in phase-transition temperatures and cooperativity upon heating. In contrast, SF increases the rigidity of the DODAB fluid phase, resulting in a smaller decrease in transition temperatures upon cooling. The hysteresis between heating and cooling decreased as the SF molar fraction increased. These effects on DODAB are similar to the ones described for other glycolipids, such as αGalCer and βGlcCer. This might be due to the orientation of the rigid and planar amide bond that connects their sphingoid bases and acyl chains, which result in a V-shaped conformation of the glycolipid molecules. The current results may be important to plan and develop new immunotherapeutic tools based on SF.
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Affiliation(s)
- Lucas de Andrade
- Departamento
de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062São Paulo, São Paulo, Brazil
| | - Evandro L. Duarte
- Instituto
de Física, Universidade de São
Paulo, Rua do Matão
1371, 05508090São
Paulo, São Paulo, Brazil
| | - M. Teresa Lamy
- Instituto
de Física, Universidade de São
Paulo, Rua do Matão
1371, 05508090São
Paulo, São Paulo, Brazil
| | - Julio H. K. Rozenfeld
- Departamento
de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062São Paulo, São Paulo, Brazil
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Vignoli Muniz GS, Duarte EL, Lorenzón EN, Cilli EM, Lamy MT. What different physical techniques can disclose about disruptions on membrane structure caused by the antimicrobial peptide Hylin a1 and a more positively charged analogue. Chem Phys Lipids 2022; 243:105173. [PMID: 34995561 DOI: 10.1016/j.chemphyslip.2022.105173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/15/2021] [Accepted: 01/02/2022] [Indexed: 11/28/2022]
Abstract
The present work monitors structural changes in anionic membranes (DPPG; 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol)) caused by the native antimicrobial peptide (AMP) Hylin a1 (Hya1; IFGAILPLALGALKNLIK-NH2) and its synthetic analogue K0Hya1 (KIFGAILPLALGALKNLIK-NH2), with an extra positive residue of lysine at the N-terminus of the peptide chain. Anionic membranes were used to mimic anionic lipids in bacteria membranes. Differential scanning calorimetry (DSC) evinced that both peptides strongly disrupt the lipid bilayers. However, whereas the native peptide (+3) induces a space-average and/or time-average disruption on DPPG bilayers, the more charged, K0Hya1 (+4), appears to be strongly attached to the membrane, clearly giving rise to the coexistence of two different lipid regions, one depleted of peptide and another one peptide-disrupted. The membrane fluorescent probe Laurdan indicates that, in average, the peptides increase the bilayer packing of fluid DPPG (above the lipid gel-fluid transition temperature) and/or decrease its polarity. Spin labels, incorporated into DPPG membrane, confirm, and extend the results obtained with Laurdan, indicating that the peptides increase the lipid packing both in gel and fluid DPPG bilayers. Therefore, our results confirm that Laurdan is often unable to monitor structural modifications induced on gel membranes by exogenous molecules. Through the measurement of the leakage of entrapped carboxyfluorescein (CF), a fluorescent dye, in DPPG large unilamellar vesicles it was possible to show that both peptides induce pore formation in DPPG bilayers. Furthermore, CF experiments show that Hylin peptides are strongly bound to DPPG bilayers in the gel phase, not being able to migrate to other DPPG vesicles. Here we discuss the complementarity of different techniques in monitoring structural alterations caused on lipid bilayers by Hylin peptides, and how it could be used to help in the understanding of the action of other exogenous molecules on biological membranes.
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Affiliation(s)
- Gabriel S Vignoli Muniz
- Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, 05508-090 São Paulo, SP, Brazil.
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, 05508-090 São Paulo, SP, Brazil
| | - Esteban N Lorenzón
- Unidade Acadêmica Especial Ciências da Saúde, Universidade Federal de Jataí, 75804-020, Jataí, GO, Brazil
| | - Eduardo M Cilli
- Instituto de Química, Universidade Estadual Paulista, Araraquara, 14800-900, SP,,Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, 05508-090 São Paulo, SP, Brazil.
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6
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Correlating biological activity to thermo-structural analysis of the interaction of CTX with synthetic models of macrophage membranes. Sci Rep 2021; 11:23712. [PMID: 34887428 PMCID: PMC8660830 DOI: 10.1038/s41598-021-02552-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 11/11/2021] [Indexed: 11/10/2022] Open
Abstract
The important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated. The biological activities performed by macrophages are related to signaling mediated by receptors expressed on the membrane surface of these cells or opening and closing of ion channels, generation of membrane curvature and pore formation. In the present work, the interaction of the CTX complex with the cell membrane of macrophages is studied, both using biological cells and synthetic lipid membranes to monitor structural alterations induced by the protein. Here we show that CTX can penetrate THP-1 cells and induce pores only in anionic lipid model membranes, suggesting that a possible access pathway for CTX to the cell is via lipids with anionic polar heads. Considering that the selectivity of the lipid composition varies in different tissues and organs of the human body, the thermostructural studies presented here are extremely important to open new investigations on the biological activities of CTX in different biological systems.
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Basso LGM, Zeraik AE, Felizatti AP, Costa-Filho AJ. Membranotropic and biological activities of the membrane fusion peptides from SARS-CoV spike glycoprotein: The importance of the complete internal fusion peptide domain. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183697. [PMID: 34274319 PMCID: PMC8280623 DOI: 10.1016/j.bbamem.2021.183697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/05/2021] [Accepted: 07/10/2021] [Indexed: 11/28/2022]
Abstract
Fusion peptides (FP) are prominent hydrophobic segments of viral fusion proteins that play critical roles in viral entry. FPs interact with and insert into the host lipid membranes, triggering conformational changes in the viral protein that leads to the viral-cell fusion. Multiple membrane-active domains from the severe acute respiratory syndrome (SARS) coronavirus (CoV) spike protein have been reported to act as the functional fusion peptide such as the peptide sequence located between the S1/S2 and S2' cleavage sites (FP1), the S2'-adjacent fusion peptide domain (FP2), and the internal FP sequence (cIFP). Using a combined biophysical approach, we demonstrated that the α-helical coiled-coil-forming internal cIFP displayed the highest membrane fusion and permeabilizing activities along with membrane ordering effect in phosphatidylcholine (PC)/phosphatidylglycerol (PG) unilamellar vesicles compared to the other two N-proximal fusion peptide counterparts. While the FP1 sequence displayed intermediate membranotropic activities, the well-conserved FP2 peptide was substantially less effective in promoting fusion, leakage, and membrane ordering in PC/PG model membranes. Furthermore, Ca2+ did not enhance the FP2-induced lipid mixing activity in PC/phosphatidylserine/cholesterol lipid membranes, despite its strong erythrocyte membrane perturbation. Nonetheless, we found that the three putative SARS-CoV membrane-active fusion peptide sequences here studied altered the physical properties of model and erythrocyte membranes to different extents. The importance of the distinct membranotropic and biological activities of all SARS-CoV fusion peptide domains and the pronounced effect of the internal fusion peptide sequence to the whole spike-mediated membrane fusion process are discussed.
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Affiliation(s)
- Luis Guilherme Mansor Basso
- Laboratório de Ciências Físicas, Centro de Ciência e Tecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Avenida Alberto Lamego, 2000, 28013-602 Campos dos Goytacazes, RJ, Brazil; Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brazil.
| | - Ana Eliza Zeraik
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Avenida Alberto Lamego, 2000, 28013-602 Campos dos Goytacazes, RJ, Brazil; Grupo de Biofísica e Biologia Estrutural "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense, 400, Centro, São Carlos, SP, Brazil
| | - Ana Paula Felizatti
- Laboratório de Produtos Naturais, Departamento de Química, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, Monjolinho, 13565905, São Carlos, SP, Brazil; Grupo de Biofísica e Biologia Estrutural "Sérgio Mascarenhas", Instituto de Física de São Carlos, Universidade de São Paulo, Avenida Trabalhador São-carlense, 400, Centro, São Carlos, SP, Brazil
| | - Antonio José Costa-Filho
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brazil.
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8
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Zhou Z, Zhao Y, Zhou D, Li L, Luo H, Cui L, Yang W. Rapid and efficient synthesis of formamidines in a catalyst-free and solvent-free system. RSC Adv 2021; 11:33868-33871. [PMID: 35497291 PMCID: PMC9042323 DOI: 10.1039/d1ra06809a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/21/2021] [Indexed: 12/15/2022] Open
Abstract
An operationally rapid and efficient synthesis of N-sulfonyl formamidines that proceeds under mild conditions was achieved by reaction of a mixture of an amine, a sulfonyl azide, and a terminal ynone under catalyst-free and solvent-free conditions. Terminal ynones provide the C source to formamidines via complete cleavage of C[triple bond, length as m-dash]C.
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Affiliation(s)
- Zitong Zhou
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
| | - Yu Zhao
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
| | - Donghua Zhou
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
| | - Li Li
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
| | - Hui Luo
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang) Zhanjiang Guangdong 524023 China
| | - Liao Cui
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
| | - Weiguang Yang
- Guangdong Key Laboratory for Research and Development of Natural Drugs, The Marine Biomedical Research Institute, Guangdong Medical University Zhanjiang 524023 China
- The Marine Biomedical Research Institute of Guangdong Zhanjiang Zhanjiang Guangdong 524023 China
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9
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Vignoli Muniz GS, Souza MC, Duarte EL, Lamy MT. Comparing the interaction of the antibiotic levofloxacin with zwitterionic and anionic membranes: Calorimetry, fluorescence, and spin label studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183622. [PMID: 33865809 DOI: 10.1016/j.bbamem.2021.183622] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/30/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
The present work compares the interaction of the antibiotic levofloxacin (LVX) with zwitterionic and anionic liposomes composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG), respectively. By using differential scanning calorimetry (DSC), and with spin labels incorporated into liposomes at two different depths of the bilayers, we investigated the changes induced on the membrane by increasing concentrations of LVX. Further information was obtained using intrinsic LVX fluorescence. Under the conditions used here, all techniques evinced that LVX has little affinity for DPPC zwitterionic membrane. Opposite to that, LVX exhibits a considerable affinity for anionic bilayers, with membrane partition constants Kp = (3.3 ± 0.5) × 102 and (4.5 ± 0.3) × 102, for gel and fluid DPPG membranes, respectively. On binding to DPPG, LVX seems to give rise to the coexistence of LVX -rich and -poor domains on DPPG membranes, as detected by DSC. At the highest LVX concentration used (20 mol%), DSC trace shows an increase in the cooperativity of DPPG gel-fluid transition, also detected by spin labels as an increase in the bilayer packing. Moreover, LVX does not induce pore formation in either DPPG or POPG vesicles. Considering the possible relevance of LVX-membrane interaction for the biological and toxicological action of the antibiotic, the findings discussed here certainly contribute to a better understanding of its action, and the planning of new drugs.
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Affiliation(s)
| | - Mariana C Souza
- Instituto de Física, Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, São Paulo, SP CEP 05508-090, Brazil.
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The interaction of a thiosemicarbazone derived from R - (+) - limonene with lipid membranes. Chem Phys Lipids 2020; 234:105018. [PMID: 33232725 DOI: 10.1016/j.chemphyslip.2020.105018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 11/21/2022]
Abstract
As a potential drug, 2-nitrobenzaldehyde-thiosemicarbazone (2-TSC), a thiosemicarbazone derived from the terpene R-(+)-limonene, was studied through calorimetric and spectroscopic techniques. Differential Scanning Calorimetry (DSC) data showed that 2-TSC causes structural changes in a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DMPC) membrane, strongly decreasing the cooperativity of the bilayer gel-fluid thermal transition. Optical absorption spectroscopy showed that 2-TSC is more soluble in ethanol and lipids than in water medium, and that the drug displays different structures in the different environments. Though 2-TSC displays no fluorescence, time resolved fluorescence showed that the drug is an effective quencher of the fluorescent probe 6-dodecanoyl-2-dimethylaminonaphthalene (Laurdan). As it is well accepted that Laurdan is positioned into the bilayer close to the membrane surface, that is possibly the localization of 2-TSC in a bilayer. Electron spin resonance (ESR) of the probe 1-palmitoyl-2-stearoyl-(14-doxyl)-sn-glycero-3-phosphocholine (14-PCSL) revealed that 2-TSC is inserted into the hydrocarbon part of the bilayer, fluidizing the lipid bilayer gel phase and rigidifying or organizing the bilayer fluid phase. Similar effects are found for other lipophilic molecules, including cholesterol. These results are useful to improve the understanding of the processes that govern the interaction of thiosemicarbazones with cell membranes, related to the activity of the drugs and their cytotoxicity.
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11
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Martins LS, Duarte EL, Lamy MT, Rozenfeld JHK. Supramolecular organization of α-galactosylceramide in pure dispersions and in cationic DODAB bilayers. Chem Phys Lipids 2020; 232:104963. [PMID: 32882224 DOI: 10.1016/j.chemphyslip.2020.104963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/01/2020] [Accepted: 08/20/2020] [Indexed: 11/30/2022]
Abstract
α-galactosylceramide (α-GalCer; KRN7000) strongly stimulates NKT cells. The structures of α-GalCer assemblies and of cationic DODAB bilayers containing α-GalCer were investigated by differential scanning calorimetry (DSC) and electron spin resonance (ESR) spectroscopy. Assemblies of α-GalCer have a very tightly packed gel phase, causing spin labels to cluster and display spin exchange interactions. An endothermic phase transition is observed by DSC, leading to a fluid phase. This phase transition peak disappears upon mixing with DODAB, showing that up to 9 mol% α-GalCer is miscible with the cationic lipid. ESR spectra show that α-GalCer decreases DODAB gel phase packing, resulting in a decrease of gel-fluid transition temperature and cooperativity in DSC thermograms of mixed bilayers. In contrast, α-GalCer increases the rigidity of the fluid phase. These effects are probably due to the conformation of the rigid amide bond that connects the phytosphingosine base of α-GalCer to its long and saturated acyl chain. Possibly, α-GalCer adopts a V-shaped conformation because of the perpendicular orientation of the amide bond towards the axes of the hydrocarbon chains. Apparently, the effect of the amide bond configuration is a key structural feature for the interaction between ceramide-based glycolipids and DODAB molecules, since we have previously reported a similar decrease of gel phase packing and increase in fluid phase rigidity for DODAB bilayers containing C24:1β-glucosylceramide. Since the structure of delivery systems is critical to the biological activity of α-GalCer, this work certainly contributes to the planning and development of novel immunotherapeutic tools.
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Affiliation(s)
- Letícia S Martins
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062, São Paulo, SP, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508090, São Paulo, SP, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, 05508090, São Paulo, SP, Brazil
| | - Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062, São Paulo, SP, Brazil.
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12
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Masukawa MK, Vequi-Suplicy CC, Duarte EL, Lamy MT. A closer look into laurdan as a probe to monitor cationic DODAB bilayers. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Martins LS, Nomura DA, Duarte EL, Riske KA, Lamy MT, Rozenfeld JHK. Structural characterization of cationic DODAB bilayers containing C24:1 β-glucosylceramide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:643-650. [PMID: 30611744 DOI: 10.1016/j.bbamem.2018.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/09/2018] [Accepted: 12/28/2018] [Indexed: 01/13/2023]
Abstract
The effect of 5 mol%, 9 mol%, and 16 mol% of C24:1 β-glucosylceramide (βGlcCer) on the structure of cationic DODAB bilayers was investigated by means of differential scanning calorimetry (DSC), electron spin resonance (ESR) spectroscopy and fluorescence microscopy. βGlcCer is completely miscible with DODAB at all fractions tested, since no domains were observed in fluorescence microscopy or ESR spectra. The latter showed that βGlcCer destabilized the gel phase of DODAB bilayers by decreasing the gel phase packing. As a consequence, βGlcCer induced a decrease in the phase transition temperature and cooperativity of DODAB bilayers, as seen in DSC thermograms. ESR spectra also showed that βGlcCer induced an increase in DODAB fluid phase order and/or rigidity. Despite their different structures, a similar effect of loosening the gel phase packing and turning the fluid phase more rigid/organized has also been observed when low molar fractions of cholesterol were incorporated in DODAB bilayers. The structural characterization of mixed membranes made of cationic lipids and glucosylceramides may be important for developing novel immunotherapeutic tools such as vaccine adjuvants.
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Affiliation(s)
- Letícia S Martins
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil
| | - Daniela A Nomura
- Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05315-970 São Paulo, SP, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05315-970 São Paulo, SP, Brazil
| | - Karin A Riske
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05315-970 São Paulo, SP, Brazil
| | - Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil.
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Exploring the pH-Induced Functional Phase Space of Human Serum Albumin by EPR Spectroscopy. MAGNETOCHEMISTRY 2018. [DOI: 10.3390/magnetochemistry4040047] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A systematic study on the self-assembled solution system of human serum albumin (HSA) and paramagnetic doxyl stearic acid (5-DSA and 16-DSA) ligands is reported covering the broad pH range 0.7–12.9, mainly using electron paramagnetic resonance (EPR) methods. It is tested to which extent the pH-induced conformational isomers of HSA reveal themselves in continuous wave (CW) EPR spectra from this spin probing approach in comparison to an established spin-labeling strategy utilizing 3-maleimido proxyl (5-MSL). Most analyses are conducted on empirical levels with robust strategies that allow for the detection of dynamic changes of ligand, as well as protein. Special emphasis has been placed on the EPR spectroscopic detection of a molten globule (MG) state of HSA that is typically found by the fluorescent probe 8-Anilino- naphthalene-1-sulfonic acid (ANS). Moreover, four-pulse double electron-electron resonance (DEER) experiments are conducted and substantiated with dynamic light scattering (DLS) data to determine changes in the solution shape of HSA with pH. All results are ultimately combined in a detailed scheme that describes the pH-induced functional phase space of HSA.
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