Temperature-Dependence of Cationic Lipid Bilayer Intermixing: Possible Role of Interdigitation

Oliveira, Tiago; Duarte, Evandro L.; Lamy, M. Teresa; Vandenbranden, Michel; Ruysschaert, Jean Marie; Lonez, Caroline

doi:10.1021/la3001569

Cited by 13 publications

(35 citation statements)

References 64 publications

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“…These ESR data are in good agreement with DSC thermograms of diC14-amidine (Fig. 5), which indicate a broad gel-fluid transition that ends before 22°C, while DMPC displays a sharp gel-fluid transition at 23.8°C (Oliveira et al 2012).…”

Section: Thermotropic Behavior: Monitoring Gel and Fluid-lipid Bilayesupporting

confidence: 86%

“…In contrast, spectra in bilayers of the zwitterionic analog dimyristoyl phosphatidylcholine (DMPC in Fig. 1) indicate a rigid bilayer up to 23°C and a fluid one at and above 24°C (Oliveira et al 2012). These ESR data are in good agreement with DSC thermograms of diC14-amidine (Fig.…”

Section: Thermotropic Behavior: Monitoring Gel and Fluid-lipid Bilayesupporting

confidence: 71%

“…3c, d). Gel and fluid phases coexistence was also observed around the gel-fluid phase transition temperature of diC14-amidine, between 19°C and 21°C (Oliveira et al 2012). Below 19°C the spectrum of 16-PCSL incorporated in diC14-amidine bilayer is typical of a membrane gel phase, and at above 22°C, the spectra are typical of a fluid bilayer.…”

Section: Thermotropic Behavior: Monitoring Gel and Fluid-lipid Bilayementioning

confidence: 80%

“…Phospholipids spin-labeled at different positions of the hydrocarbon chain (5-, 7-, 10-, 12-and 16-PCSL) show similar anisotropic spectra at different depths of diC14-amidine gel phase membranes (Oliveira et al 2012). This is in contrast with the spectra observed for the same probes embedded in DMPC, the zwitterionic analog which has the same hydrophobic domain of C14 atoms chains and is organized as a typical gel phase bilayer (Oliveira et al 2012) (Fig. 6, at the top, shows, for comparison, the spectra of the different labels incorporated in DMPC and diC14-amidine bilayers at the gel phase).…”

Section: Different Gel Bilayer Structures: Interdigitationmentioning

confidence: 97%

“…Similarly, highly fusogenic diC14-amidine membranes (Oliveira et al 2012) have successfully delivered nucleic acids (El Ouahabi et al 1996;Ruysschaert et al 1994) and stimulated the formation of immune responses (Tanaka et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Structural insights on biologically relevant cationic membranes by ESR spectroscopy

et al. 2017

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Cationic bilayers have been used as models to study membrane fusion, templates for polymerization and deposition of materials, carriers of nucleic acids and hydrophobic drugs, microbicidal agents and vaccine adjuvants. The versatility of these membranes depends on their structure. Electron spin resonance (ESR) spectroscopy is a powerful technique that employs hydrophobic spin labels to probe membrane structure and packing. The focus of this review is the extensive structural characterization of cationic membranes prepared with dioctadecyldimethylammonium bromide or diC14-amidine to illustrate how ESR spectroscopy can provide important structural information on bilayer thermotropic behavior, gel and fluid phases, phase coexistence, presence of bilayer interdigitation, membrane fusion and interactions with other biologically relevant molecules.

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Section: Thermotropic Behavior: Monitoring Gel and Fluid-lipid Bilayesupporting

confidence: 86%

Section: Thermotropic Behavior: Monitoring Gel and Fluid-lipid Bilayesupporting

confidence: 71%

Section: Thermotropic Behavior: Monitoring Gel and Fluid-lipid Bilayementioning

confidence: 80%

Section: Different Gel Bilayer Structures: Interdigitationmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Structural insights on biologically relevant cationic membranes by ESR spectroscopy

et al. 2017

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Critical residues involved in Toll-like receptor 4 activation by cationic lipid nanocarriers are not located at the lipopolysaccharide-binding interface

Lonez

Irvine

Pizzuto

et al. 2015

Cell. Mol. Life Sci.

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DiC14-amidine is a cationic lipid that was originally designed as a lipid nanocarrier for nucleic acid transport, and turned out to be a Toll-like receptor 4 (TLR4) agonist as well. We found that while E. coli lipopolysaccharide (LPS) is a TLR4 agonist in all species, diC14-amidine nanoliposomes are full agonists for human, mouse and cat receptors but weak horse agonists. Taking advantage of this unusual species specificity, we used chimeric constructs based on the human and horse sequences and identified two regions in the human TLR4 that modulate the agonist activity of diC14-amidine. Interestingly, these regions lie outside the known LPS-binding domain. Competition experiments also support our hypothesis that diC14-amidine interacts primarily with TLR4 hydrophobic crevices located at the edges of the TLR4/TLR4* dimerization interface. We have characterized potential binding modes using molecular docking analysis and suggest that diC14-amidine nanoliposomes activate TLR4 by facilitating its dimerization in a process that is myeloid differentiation 2 (MD-2)-dependent and cluster of differentiation 14 (CD14)-independent. Our data suggest that TLR4 may be activated through binding at different anchoring points, expanding the repertoire of TLR4 ligands to non-MD-2-binding lipids.Electronic supplementary materialThe online version of this article (doi:10.1007/s00018-015-1915-1) contains supplementary material, which is available to authorized users.

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Structural characterization of novel cationic diC16-amidine bilayers: Evidence for partial interdigitation

Rozenfeld

Duarte

Ruysschaert

et al. 2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

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In this work, the bilayer structure of novel cationic lipid diC16-amidine was compared to the one of zwitterionic dipalmitoyl phosphatidylcholine ( DPPC), which shares the same hydrophobic domain. Differential scanning calorimetry shows that DPPC and diC16-am idine bilayers have similar phase transition temperatures, but diC16-a midine membranes display a less cooperative phase transition and an absence of pretransition. Both bilayers were analyzed from surface to core, using 5-, 7-, 10-, 12-, 14-, and 16-PCSL spin labels. As expected, electron spin resonance (ESR) spectra show that the gel phase of DPPC presents a flexibility gradient toward the core. In contrast, this gradient exists in the gel phase of diC16-amidine bilayers but only down to the 12th lipid tail carbon. The 14th and 16th carbons of the cationic lipid are in a very rigid environment, similar to the one observed at the bilayer surface. These data suggest that diC16-amidine molecules are organized in a partially interdigitated gel phase. ESR spectroscopy also shows that the lamellar fluid phase of diC16-amidine is more rigid than the one of DPPC. Fluorescence resonance energy transfer assays reveal that diC16-amidine displays a more efficient fusogenic activity in the gel phase than in the fluid one, suggesting that the partial interdigitation of the gel phase is important for the fusion process to occur. Since the gel- fl uid transition temperature is 42 ·c. diC16-amid ine is fusogenic at the physiological temperature and is therefore a promising lipid for delivery applications without the need of helper lipids.

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Temperature-Dependence of Cationic Lipid Bilayer Intermixing: Possible Role of Interdigitation

Cited by 13 publications

References 64 publications

Structural insights on biologically relevant cationic membranes by ESR spectroscopy

Structural insights on biologically relevant cationic membranes by ESR spectroscopy

Critical residues involved in Toll-like receptor 4 activation by cationic lipid nanocarriers are not located at the lipopolysaccharide-binding interface

Structural characterization of novel cationic diC16-amidine bilayers: Evidence for partial interdigitation

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