Interaction of Fusidic Acid with Lipid Membranes: Implications to the Mechanism of Antibiotic Activity

Abstract

We have studied the effects of cholesterol and steroid-based antibiotic fusidic acid (FA) on the behavior of lipid bilayers using a variety of experimental techniques together with atomic-scale molecular dynamics simulations. Capillary electrophoretic measurements showed that FA was incorporated into fluid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine membranes. Differential scanning calorimetry in turn showed that FA only slightly altered the thermodynamic properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers, whereas cholesterol abolished all endotherms when the mole fraction of cholesterol (X(chol)) was >0.20. Fluorescence spectroscopy was then used to further characterize the influence of these two steroids on DPPC large unilamellar vesicles. In the case of FA, our result strongly suggested that FA was organized into lateral microdomains with increased water penetration into the membrane. For cholesterol/DPPC mixtures, fluorescence spectroscopy results were compatible with the formation of the liquid-ordered phase. A comparison of FA and cholesterol-induced effects on DPPC bilayers through atomistic molecular dynamics simulations showed that both FA and cholesterol tend to order neighboring lipid chains. However, the ordering effect of FA was slightly weaker than that of cholesterol, and especially for deprotonated FA the difference was significant. Summarizing, our results show that FA is readily incorporated into the lipid bilayer where it is likely to be enriched into lateral microdomains. These domains could facilitate the association of elongation factor-G into lipid rafts in living bacteria, enhancing markedly the antibiotic efficacy of FA.

Shedding light on the puzzle of drug-membrane interactions: Experimental techniques and molecular dynamics simulations

“…(2006) studied the interaction of fusidic acid with a DPPC membrane by combining experimental techniques and MD simulations [139]. All experimental techniques, viz., capillary electrochromatography, DSC and fluorescence spectroscopy measurements, showed drug incorporation into the bilayer and their effect on the membrane biophysical properties, whereas MD studies provided information regarding the drug locations [139].…”

Experimental and theoretical studies of emodin interacting with a lipid bilayer of DMPC

“…In some cases, more than one location was found to be stable, as for instance Limonene, Perillyl alcohol, Perillaldehyde, Perillic acid (Witzke et al 2010), and Diploptene and Bacteriohopanetetrol (Poger and Mark 2013), which are partitioned in the bilayer changing from one location to another. Other molecules, like Fusidic acid (Falck et al 2006), uncharged Lidocain (Högberg et al 2007) and Emodin (this work), prefer the head-tail interface near the ester or glycerol groups of the lipid. For those molecules that were studied in the neutral form (uncharged) and deprotonated form (charged), in general the uncharged form are located deeper in the bilayer, as expected.…”

“…There are several molecular features that govern the behavior of a drug in cell membranes such as size, shape, solubility, hydrophilicity, lipophilicity, and pK a , among others. Previously, many authors have reported studies of the interaction of drugs and membrane models with experimental technics (Nunes et al 2011;Lucio et al 2009;Fuchs et al 1990) and molecular dynamic (MD) simulations (Robinson et al 1995;Gabdouline et al 1996;Smondyrev andBerkowitz 1999, 2001;Hofsäß et al 2003;Pereira et al 2004;Falck et al 2006;Högberg et al 2007;Seddon et al 2009;Sirk et al 2009;Boggara and Krishnamoorti 2010;Witzke et al 2010;Orsi andEssex 2010, Koukoulitsa et al 2011;Nitschke et al 2012;Poger and Mark 2013;Loverde 2014;Jalili and Saeedi 2016). In particular, studies based on drug partitioning in lipid bilayers and the thermodynamics of drug/lipid interaction have great importance in understanding the reaction mechanisms of antitumor drugs and to design new cell membrane-targeted drugs (Boggara and Krishnamoorti 2010;Jendrossek and Handrick 2003;Goldstein et al 2011;Choi et al 2013).…”

Nanotechnology approaches for antibacterial drug delivery: Preparation and microbiological evaluation of fusogenic liposomes carrying fusidic acid

“…Recent studies by Holopainen and colleagues [20,21] have linked the high lipophilic character of FUS to its antibacterial activity profile. In fact, experiments using various model biomembranes showed that FUS is able to interact strongly with the phospholipid bilayers and in particular with the negatively charged lipids [20], remaining embedded in the membrane and forming lateral domains.…”

“…In fact, experiments using various model biomembranes showed that FUS is able to interact strongly with the phospholipid bilayers and in particular with the negatively charged lipids [20], remaining embedded in the membrane and forming lateral domains. This behaviour ultimately hinders drug diffusion into the cytoplasm and thus its biological effects at the target site.…”