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4808 KiB

Open AccessArticle

A Polarizable Atomic Multipole-Based Force Field for Molecular Dynamics Simulations of Anionic Lipids

by Huiying Chu, Xiangda Peng, Yan Li, Yuebin Zhang and Guohui Li

Molecules 2018, 23(1), 77; https://doi.org/10.3390/molecules23010077 - 31 Dec 2017

Cited by 10 | Viewed by 4618

Abstract

In all of the classical force fields, electrostatic interaction is simply treated and explicit electronic polarizability is neglected. The condensed-phase polarization, relative to the gas-phase charge distributions, is commonly accounted for in an average way by increasing the atomic charges, which remain fixed [...] Read more.

In all of the classical force fields, electrostatic interaction is simply treated and explicit electronic polarizability is neglected. The condensed-phase polarization, relative to the gas-phase charge distributions, is commonly accounted for in an average way by increasing the atomic charges, which remain fixed throughout simulations. Based on the lipid polarizable force field DMPC and following the same framework as Atomic Multipole Optimized Energetics for BiomoleculAr (AMOEBA) simulation, the present effort expands the force field to new anionic lipid models, in which the new lipids contain DMPG and POPS. The parameters are compatible with the AMOEBA force field, which includes water, ions, proteins, etc. The charge distribution of each atom is represented by the permanent atomic monopole, dipole and quadrupole moments, which are derived from the ab initio gas phase calculations. Many-body polarization including the inter- and intramolecular polarization is modeled in a consistent manner with distributed atomic polarizabilities. Molecular dynamics simulations of the two aqueous DMPG and POPS membrane bilayer systems, consisting of 72 lipids with water molecules, were then carried out to validate the force field parameters. Membrane width, area per lipid, volume per lipid, deuterium order parameters, electron density profile, electrostatic potential difference between the center of the bilayer and water are all calculated, and compared with limited experimental data. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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3384 KiB

Open AccessArticle

trans-Double Bond-Containing Liposomes as Potential Carriers for Drug Delivery

by Giorgia Giacometti, Marina Marini, Kyriakos Papadopoulos, Carla Ferreri and Chryssostomos Chatgilialoglu

Molecules 2017, 22(12), 2082; https://doi.org/10.3390/molecules22122082 - 28 Nov 2017

Cited by 13 | Viewed by 6836

Abstract

The use of liposomes has been crucial for investigations in biomimetic chemical biology as a membrane model and in medicinal chemistry for drug delivery. Liposomes are made of phospholipids whose biophysical characteristics strongly depend on the type of fatty acid moiety, where natural [...] Read more.

The use of liposomes has been crucial for investigations in biomimetic chemical biology as a membrane model and in medicinal chemistry for drug delivery. Liposomes are made of phospholipids whose biophysical characteristics strongly depend on the type of fatty acid moiety, where natural unsaturated lipids always have the double bond geometry in the cis configuration. The influence of lipid double bond configuration had not been considered so far with respect to the competence of liposomes in delivery. We were interested in evaluating possible changes in the molecular properties induced by the conversion of the double bond from cis to trans geometry. Here we report on the effects of the addition of trans-phospholipids supplied in different amounts to other liposome constituents (cholesterol, neutral phospholipids and cationic surfactants), on the size, ζ-potential and stability of liposomal formulations and on their ability to encapsulate two dyes such as rhodamine B and fluorescein. From a biotechnological point of view, trans-containing liposomes proved to have different characteristics from those containing the cis analogues, and to influence the incorporation and release of the dyes. These results open new perspectives in the use of the unnatural lipid geometry, for the purpose of changing liposome behavior and/or of obtaining molecular interferences, also in view of synergic effects of cell toxicity, especially in antitumoral strategies. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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10178 KiB

Open AccessArticle

Alcohol Interactions with Lipid Bilayers

by Tomáš Kondela, Jana Gallová, Thomas Hauß, Jonathan Barnoud, Siewert-J. Marrink and Norbert Kučerka

Molecules 2017, 22(12), 2078; https://doi.org/10.3390/molecules22122078 - 28 Nov 2017

Cited by 26 | Viewed by 6785

Abstract

We investigate the structural changes to lipid membrane that ensue from the addition of aliphatic alcohols with various alkyl tail lengths. Small angle neutron diffraction from flat lipid bilayers that are hydrated through water vapor has been employed to eliminate possible artefacts of [...] Read more.

We investigate the structural changes to lipid membrane that ensue from the addition of aliphatic alcohols with various alkyl tail lengths. Small angle neutron diffraction from flat lipid bilayers that are hydrated through water vapor has been employed to eliminate possible artefacts of the membrane curvature and the alcohol’s membrane-water partitioning. We have observed clear changes to membrane structure in both transversal and lateral directions. Most importantly, our results suggest the alteration of the membrane-water interface. The water encroachment has shifted in the way that alcohol loaded bilayers absorbed more water molecules when compared to the neat lipid bilayers. The experimental results have been corroborated by molecular dynamics simulations to reveal further details. Namely, the order parameter profiles have been fruitful in correlating the mechanical model of structural changes to the effect of anesthesia. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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7976 KiB

Open AccessArticle

Differential Interaction of Antimicrobial Peptides with Lipid Structures Studied by Coarse-Grained Molecular Dynamics Simulations

by Galo E. Balatti, Ernesto E. Ambroggio, Gerardo D. Fidelio, M. Florencia Martini and Mónica Pickholz

Molecules 2017, 22(10), 1775; https://doi.org/10.3390/molecules22101775 - 20 Oct 2017

Cited by 22 | Viewed by 6718

Abstract

In this work; we investigated the differential interaction of amphiphilic antimicrobial peptides with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid structures by means of extensive molecular dynamics simulations. By using a coarse-grained (CG) model within the MARTINI force field; we simulated the peptide–lipid system from three different [...] Read more.

In this work; we investigated the differential interaction of amphiphilic antimicrobial peptides with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid structures by means of extensive molecular dynamics simulations. By using a coarse-grained (CG) model within the MARTINI force field; we simulated the peptide–lipid system from three different initial configurations: (a) peptides in water in the presence of a pre-equilibrated lipid bilayer; (b) peptides inside the hydrophobic core of the membrane; and (c) random configurations that allow self-assembled molecular structures. This last approach allowed us to sample the structural space of the systems and consider cooperative effects. The peptides used in our simulations are aurein 1.2 and maculatin 1.1; two well-known antimicrobial peptides from the Australian tree frogs; and molecules that present different membrane-perturbing behaviors. Our results showed differential behaviors for each type of peptide seen in a different organization that could guide a molecular interpretation of the experimental data. While both peptides are capable of forming membrane aggregates; the aurein 1.2 ones have a pore-like structure and exhibit a higher level of organization than those conformed by maculatin 1.1. Furthermore; maculatin 1.1 has a strong tendency to form clusters and induce curvature at low peptide–lipid ratios. The exploration of the possible lipid–peptide structures; as the one carried out here; could be a good tool for recognizing specific configurations that should be further studied with more sophisticated methodologies. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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1404 KiB

Open AccessArticle

Bioactivity In Vitro of Quercetin Glycoside Obtained in Beauveria bassiana Culture and Its Interaction with Liposome Membranes

by Paulina Strugała, Tomasz Tronina, Ewa Huszcza and Janina Gabrielska

Molecules 2017, 22(9), 1520; https://doi.org/10.3390/molecules22091520 - 11 Sep 2017

Cited by 30 | Viewed by 5625

Abstract

Quercetin (Q) was used as substrate for regioselective glycosylation at the C-7 position catalyzed by Beauveria bassiana AM278 strain. As a result the glycoside quercetin 7-O-β-d-(4″-O-methyl)glucopyranoside (Q 7-MeGlu) was formed. The goal of the studies was to [...] Read more.

Quercetin (Q) was used as substrate for regioselective glycosylation at the C-7 position catalyzed by Beauveria bassiana AM278 strain. As a result the glycoside quercetin 7-O-β-d-(4″-O-methyl)glucopyranoside (Q 7-MeGlu) was formed. The goal of the studies was to determine the anti-oxidative (liposome membrane protection against free radicals IC₅₀^{Q 7-MeGlu} = 5.47 and IC₅₀^Q = 4.49 µM) and anti-inflammatory (COX-1 and COX-2 enzymes activity inhibition) properties of Q 7-MeGlu as compared to Q. Every attempt was made to clarify the antioxidant activity of these molecules, which are able to interact with egg phosphatidylcholine liposomes, using a fluorometric method (by applying the probes MC540, TMA-DPH and DPH). The results indicated that Q 7-MeGlu and Q are responsible for increasing the packing order, mainly in the hydrophilic but also in hydrophobic regions of the membrane (Q > Q 7-MeGlu). These observations, confirmed by a ¹H-NMR method, are key to understanding their antioxidant activity which is probably caused by the stabilizing effect on the lipid membranes. The results showed that Q 7-MeGlu and Q have ability to quench the human serum albumin (HSA) intrinsic fluorescence through a static quenching mechanism. The results of thermodynamic parameters indicated that the process of formation complexes between studied molecules and HSA was spontaneous and caused through Van der Waals interactions and hydrogen bonding. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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Review

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14 pages, 249 KiB

Open AccessReview

Phospholipid and Lipid Derivatives as Potential Neuroprotective Compounds

by Seyed Khosrow Tayebati

Molecules 2018, 23(9), 2257; https://doi.org/10.3390/molecules23092257 - 05 Sep 2018

Cited by 22 | Viewed by 4145

Abstract

The worldwide demographical trend is changing towards a more elderly population. In particular, this phenomenon is increasing the number of neurodegenerative disease cases (e.g., Alzheimer’s disease) in advanced countries. Therefore, there is a fertile field for neuroprotective approaches to address this problem. A [...] Read more.

The worldwide demographical trend is changing towards a more elderly population. In particular, this phenomenon is increasing the number of neurodegenerative disease cases (e.g., Alzheimer’s disease) in advanced countries. Therefore, there is a fertile field for neuroprotective approaches to address this problem. A useful strategy to protect the membrane integrity of cells and reduce inflammatory processes. In this context, the neurons represent particularly vulnerable cells. Thus, a protection strategy should include their membrane preservation and improved anti-inflammatory processes. The contribution of phospholipid derivatives to this issue is crucial and many articles evidence their role in both health and disease. On the other hand, some lipids containing choline actively participate to increase the choline levels in the nervous system. It is acknowledged that the cholinergic system plays a pivotal role both in the central and in the peripheral nervous system. Neurons cannot synthesize choline, which is provided by the diet. The reuptake of ACh and its hydrolysis represent the principal source of choline. Therefore, to cover choline needs, choline-containing lipids may be used. There are different works which demonstrate their neuroprotective features This review article analyzes phospholipid and lipid derivatives that through different mechanisms are involved in these protective processes, although, sometimes the same molecules may behave as neurotoxic elements, therefore, their protective machinery should be detailed better. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

2843 KiB

Open AccessReview

The Diverse Range of Possible Cell Membrane Interactions with Substrates: Drug Delivery, Interfaces and Mobility

by Hyun-Sook Jang

Molecules 2017, 22(12), 2197; https://doi.org/10.3390/molecules22122197 - 11 Dec 2017

Cited by 13 | Viewed by 6926

Abstract

The cell membrane has gained significant attention as a platform for the development of bio-inspired nanodevices due to its immune-evasive functionalities and copious bio-analogs. This review will examine several uses of cell membranes such as (i) therapeutic delivery carriers with or without substrates [...] Read more.

The cell membrane has gained significant attention as a platform for the development of bio-inspired nanodevices due to its immune-evasive functionalities and copious bio-analogs. This review will examine several uses of cell membranes such as (i) therapeutic delivery carriers with or without substrates (i.e., nanoparticles and artificial polymers) that have enhanced efficiency regarding copious cargo loading and controlled release, (ii) exploiting nano-bio interfaces in membrane-coated particles from the macro- to the nanoscales, which would help resolve the biomedical issues involved in biological interfacing in the body, and (iii) its effects on the mobility of bio-moieties such as lipids and/or proteins in cell membranes, as discussed from a biophysical perspective. We anticipate that this review will influence both the development of novel anti-phagocytic delivery cargo and address biophysical problems in soft and complex cell membrane. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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1809 KiB

Open AccessReview

Phospholipids of Animal and Marine Origin: Structure, Function, and Anti-Inflammatory Properties

by Ronan Lordan, Alexandros Tsoupras and Ioannis Zabetakis

Molecules 2017, 22(11), 1964; https://doi.org/10.3390/molecules22111964 - 14 Nov 2017

Cited by 190 | Viewed by 21561

Abstract

In this review paper, the latest literature on the functional properties of phospholipids in relation to inflammation and inflammation-related disorders has been critically appraised and evaluated. The paper is divided into three sections: ^{Section 1} presents an overview of the relationship between structures [...] Read more.

In this review paper, the latest literature on the functional properties of phospholipids in relation to inflammation and inflammation-related disorders has been critically appraised and evaluated. The paper is divided into three sections: ^{Section 1} presents an overview of the relationship between structures and biological activities (pro-inflammatory or anti-inflammatory) of several phospholipids with respect to inflammation. ^{Section 2} and ^{Section 3} are dedicated to the structures, functions, compositions and anti-inflammatory properties of dietary phospholipids from animal and marine sources. Most of the dietary phospholipids of animal origin come from meat, egg and dairy products. To date, there is very limited work published on meat phospholipids, undoubtedly due to the negative perception that meat consumption is an unhealthy option because of its putative associations with several chronic diseases. These assumptions are addressed with respect to the phospholipid composition of meat products. Recent research trends indicate that dairy phospholipids possess anti-inflammatory properties, which has led to an increased interest into their molecular structures and reputed health benefits. Finally, the structural composition of phospholipids of marine origin is discussed. Extensive research has been published in relation to ω-3 polyunsaturated fatty acids (PUFAs) and inflammation, however this research has recently come under scrutiny and has proved to be unreliable and controversial in terms of the therapeutic effects of ω-3 PUFA, which are generally in the form of triglycerides and esters. Therefore, this review focuses on recent publications concerning marine phospholipids and their structural composition and related health benefits. Finally, the strong nutritional value of dietary phospholipids are highlighted with respect to marine and animal origin and avenues for future research are discussed. Full article

(This article belongs to the Special Issue Phospholipids: Structure and Function)

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