Towards biomimics of cell membranes: Structural effect of phosphatidylinositol triphosphate (PIP3) on a lipid bilayer

Luchini, Alessandra; Nzulumike, Achebe N.O.; Lind, Tania Kjellerup; Nylander, Tommy; Barker, Robert; Arleth, Lise; Mortensen, K.; Cárdenas, Marité

doi:10.1016/j.colsurfb.2018.09.031

Cited by 26 publications

(26 citation statements)

References 52 publications

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“…In the absence of (and presence of 10 mol%) cholesterol, the lipid bilayer core thickness was reported to be 30 Å 31 , 25.8 (34.1) Å 11,32 and 21.8 (28.2) Å 11,32 for POPC, DMPC and DLPC respectively at similar experimental conditions. Therefore, these SLBs should probe whether the bilayer core thickness affects the positioning of cholesterol within the lipid bilayer structure: the thicker DMPC and POPC bilayers should lead to cholesterol being closer to the headgroups, while DLPC should lead to cholesterol being gathered in the middle of the core.…”

Section: Discussionmentioning

confidence: 94%

The Production of Matchout-Deuterated Cholesterol and the Study of Bilayer-Cholesterol Interactions

Waldie

Moulin

Porcar

et al. 2019

Sci Rep

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The deuteration of biomolecules provides advanced opportunities for neutron scattering studies. For low resolution studies using techniques such as small-angle neutron scattering and neutron reflection, the level of deuteration of a sample can be varied to match the scattering length density of a specific D2O/H2O solvent mixture. This can be of major value in structural studies where specific regions of a complex system can be highlighted, and others rendered invisible. This is especially useful in analyses of the structure and dynamics of membrane components. In mammalian membranes, the presence of cholesterol is crucial in modulating the properties of lipids and in their interaction with proteins. Here, a protocol is described for the production of partially deuterated cholesterol which has a neutron scattering length density that matches that of 100% D2O solvent (hereby named matchout cholesterol). The level of deuteration was determined by mass spectrometry and nuclear magnetic resonance. The cholesterol match-point was verified experimentally using small angle neutron scattering. The matchout cholesterol was used to investigate the incorporation of cholesterol in various phosphatidylcholine supported lipid bilayers by neutron reflectometry. The study included both saturated and unsaturated lipids, as well as lipids with varying chain lengths. It was found that cholesterol is distributed asymmetrically within the bilayer, positioned closer to the headgroups of the lipids than to the middle of the tail core, regardless of the phosphatidylcholine species.

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Section: Discussionmentioning

confidence: 94%

The Production of Matchout-Deuterated Cholesterol and the Study of Bilayer-Cholesterol Interactions

Waldie

Moulin

Porcar

et al. 2019

Sci Rep

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“…Figure 1(A) shows a representative NR profile measured for the SLB in D 2 O (green circles), together with the fitting curve (red continuous line). The curve was analysed with MOTOFIT and, consistently with the literature (Montis et al ., 2016, 2020; Luchini et al ., 2019), it was possible to model the profile of the SLB as a stack of five layers (see scheme in Fig. 1B): the silicon oxide layer, a layer of solvent (D 2 O), a layer for the polar headgroups in contact with the support (inner heads), a layer for the lipid chains (chains) and, finally, a layer for the polar headgroups in contact with the solvent (outer heads).…”

Section: Resultsmentioning

confidence: 99%

Gold nanoparticles interacting with synthetic lipid rafts: an AFM investigation

Ridolfi

Caselli

Montis

et al. 2020

Journal of Microscopy

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Inorganic nanoparticles (NPs) represent promising examples of engineered nanomaterials, providing interesting biomedical solutions in several fields, like therapeutics and diagnostics. Despite the extensive number of investigations motivated by their remarkable potential for nanomedicinal applications, the interactions of NPs with biological interfaces are still poorly understood. The effect of NPs on living organisms is mediated by biological barriers, such as the cell plasma membrane, whose lateral heterogeneity is thought to play a prominent role in NPs adsorption and uptake pathways. In particular, biological membranes feature the presence of rafts, that is segregated lipid micro and/or nanodomains in the so-called liquid ordered phase (L o), immiscible with the surrounding liquid disordered phase (L d). Rafts are involved in various biological functions and act as sites for the selective adsorption of materials on the membrane. Indeed, the thickness mismatch present along their boundaries generates energetically favourable conditions for the adsorption of NPs. Despite its clear implications in NPs internalisation processes and cytotoxicity, a direct proof of the selective adsorption of NPs along the rafts' boundaries is still missing to date. Here we use multicomponent supported lipid bilayers (SLBs) as reliable synthetic models, reproducing the nanometric lateral heterogeneity of cell membranes. After being characterised by atomic force microscopy (AFM) and neutron reflectivity (NR), multidomain SLBs are challenged by prototypical inorganic nanoparticles, that is citrated gold nanoparticles (AuNPs), under simplified and highly controlled conditions. By exploiting AFM, we demonstrate that AuNPs preferentially target lipid phase

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“…1−4 To make more appropriate mimics of mammalian membranes, PC is typically mixed with either sterols 5 or charged lipids such as phosphatidylserine, 6 phosphatidylglycerol (PG), 7 and most recently phosphatidylinositols. 8 For bacterial membranes, on the other hand, mixtures of PC with phosphatidylethanolamine (PE) 9 and PG 10,11 have been used mainly due to the belief that it is not possible to form SLBs of high coverage via the vesicle fusion method using PE and PG lipids. 12 In some cases, pure PC membranes were used to determine the mechanism of action of antimicrobial compounds.…”

Section: Introductionmentioning

confidence: 99%

Formation and Characterization of Supported Lipid Bilayers Composed of Phosphatidylethanolamine and Phosphatidylglycerol by Vesicle Fusion, a Simple but Relevant Model for Bacterial Membranes

2019

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Supported lipid bilayers (SLBs) are simple and robust biomimics with controlled lipid composition that are widely used as models of both mammalian and bacterial membranes. However, the lipids typically used for SLB formation poorly resemble those of bacterial cell membranes due to the lack of available protocols to form SLBs using mixtures of lipids relevant for bacteria such as phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). Although a few reports have been published recently on the formation of SLBs from Escherichia coli lipid extracts, a detailed understanding of these systems is challenging due to the complexity of the lipid composition in such natural extracts. Here, we present for the first time a simple and reliable protocol optimized to form high-quality SLBs using mixtures of PE and PG at compositions relevant for Gram-negative membranes. We show using neutron reflection and quartz microbalance not only that Ca 2+ ions and temperature are key parameters for successful bilayer deposition but also that mass transfer to the surface is a limiting factor. Continuous flow of the lipid suspension is thus crucial for obtaining full SLB coverage. We furthermore characterize the resulting bilayers and report structural parameters, for the first time for PE and PG mixtures, which are in good agreement with those reported earlier for pure POPE vesicles. With this protocol in place, more suitable and reproducible studies can be conducted to understand biomolecular processes occurring at cell membranes, for example, for testing specificities and to unravel the mechanism of interaction of antimicrobial peptides.

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Towards biomimics of cell membranes: Structural effect of phosphatidylinositol triphosphate (PIP3) on a lipid bilayer

Abstract: Marité (2019) Towards biomimics of cell membranes: Structural effect of phosphatidylinositol triphosphate (PIP3) on a lipid bilayer.

Cited by 26 publications

References 52 publications

The Production of Matchout-Deuterated Cholesterol and the Study of Bilayer-Cholesterol Interactions

The Production of Matchout-Deuterated Cholesterol and the Study of Bilayer-Cholesterol Interactions

Gold nanoparticles interacting with synthetic lipid rafts: an AFM investigation

Formation and Characterization of Supported Lipid Bilayers Composed of Phosphatidylethanolamine and Phosphatidylglycerol by Vesicle Fusion, a Simple but Relevant Model for Bacterial Membranes

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