Bleomycin-induced trans lipid formation in cell membranes and in liposome models

Cell cultures of NTera-2 cells incubated with bleomycin and liposomes as biomimetic models of cell membranes were used for examining some novel aspects of drug-metal induced reactivity with unsaturated lipids under oxidative conditions. In cell cultures, bleomycin was found for the first time to cause the formation of trans fatty acids. The chemical basis of this transformation was ascertained by liposome experiments, using bleomycin-iron complexes in the presence of thiol as a reducing agent that by incubation at 37 °C gave rise to the thiyl radical-catalysed double bond isomerisation of membrane phospholipids. The effect of oxygen and reagent concentrations on the reaction outcome was studied. An interesting scenario of free radical reactivity is proposed, which can be relevant for understanding the role of membrane lipids in antitumoral treatments and drug carrier interaction.Fil: Cort, Aysegul. Akdeniz University. Faculty of Medicine; Turquía. Consiglio Nazionale delle Ricerche; ItaliaFil: Ozben, Tomris. Akdeniz University. Faculty of Medicine; TurquíaFil: Sansone, Anna. Consiglio Nazionale delle Ricerche; ItaliaFil: Barata Vallejo, Sebastian. Consiglio Nazionale delle Ricerche; Italia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chatgilialoglu, Chryssostomos. Demokritos National Centre For Scientific Research; GreciaFil: Ferreri, Carla. Consiglio Nazionale delle Ricerche; Itali

Qualitative analysis of phospholipids and their oxidised derivatives - used techniques and examples of their applications related to lipidomic research and food analysis.

Phospholipids (PLs) are important biomolecules that not only constitute structural building blocks and scaffolds of cell and organelle membranes but also play a vital role in cell biochemistry and physiology. Moreover, dietary exogenous PLs are characterised by high nutritional value and other beneficial health effects, which are confirmed by numerous epidemiological studies. For this reason, PLs are of high interest in lipidomics that targets both the analysis of membrane lipid distribution as well as correlates composition of lipids with their effects on functioning of cells, tissues and organs. Lipidomic assessments follow-up the changes occurring in living organisms, such as free radical attack and oxidative modifications of the polyunsaturated fatty acids (PUFAs) build in PL structures. Oxidised PLs (oxPLs) can be generated exogenously and supplied to organisms with processed food or formed endogenously as a result of oxidative stress. Cellular and tissue oxPLs can be a biomarker predictive of the development of numerous diseases such as atherosclerosis or neuroinflammation. Therefore, suitable high-throughput analytical techniques, which enable comprehensive analysis of PL molecules in terms of the structure of hydrophilic group, fatty acid (FA) composition and oxidative modifications of FAs, have been currently developed. This review addresses all aspects of PL analysis, including lipid isolation, chromatographic separation of PL classes and species, as well as their detection. The bioinformatic tools that enable handling of a large amount of data generated during lipidomic analysis are also discussed. In addition, imaging techniques such as confocal microscopy and mass spectrometry imaging for analysis of cellular lipid maps, including membrane PLs, are presented

The influence of antioxidants in the thiyl radical induced lipid peroxidation and geometrical isomerization in micelles of linoleic acid

The biomimetic model of micelles of linoleic acid containing 2-mercaptoethanol and the antioxidant was examined under gamma irradiation up to 400 Gy in aerobic or deoxygenated conditions where thiyl radicals are the main reactive species. Lipid peroxidation was retarded by ascorbic acid and α-tocopherol, whereas this process was strongly inhibited by resveratrol as effectively as the ascorbic acid/α-tocopherol mixture. Furthermore, antioxidants have a much stronger inhibitory effect on the peroxidation in the presence of 2-mercaptoethanol, and at the same time show protective properties of the double bond, decreasing the cis–trans isomerization. Under anaerobic conditions cis–trans isomerization occurred and antioxidants efficiency increased along the series: resveratrol α-tocopherol ascorbic acid. This result is explained taking into account the double bond localization in the hydrophobic core of the micelle and the need of co- localization of the antioxidant in order to get an anti-isomerizing activity and protection of the natural lipid geometry

Lipid geometrical isomerism: from chemistry to biology and diagnostics.

Lipidomics, the discipline regarding chemical and metabolic lipid fates in living organisms, has brought about a successful innovation to lipid research. Expansion of trans lipid research can be easily foreseen in analytics, chemical mechanisms, liposome and oil technology, lipidomics, and diagnostics. Innovative fields can also include the design of molecular switches, taking advantage of the different sensitivity of trans- and cis-containing membranes to physical and chemical stimuli, as well as the determination of biological and pharmacological strategies based on the tunable molecular interactions produced by the exchange of the natural cis with the unnatural trans geometry. The presence of trans lipids in membranes also has a profound influence on temperature sensitivity as tested by insertion of a probe sensitive to the lipid environment, such as cis-parinaric acid, using accurate stopped-flow fluorescence measurements

Revisiting the reaction of hydroxyl radicals with vicinal diols in water

The carbonyl products of the reactions of hydroxyl radicals with three vicinal diols (ethane-1,2-diol, propane-1,2-diol and butane-2,3-diol) have been identified and quantified. Hydroxyl radicals were produced by gamma-radiolysis of N2O-saturated aqueous solutions. The reactions result in the formation of alkoxyl radicals (15%) followed by beta-fragmentation, and alpha-hydroxyl alkyl radicals that undergo H2O elimination. The latter process is part of a radical chain reaction at higher diol concentrations.Fil: Jiang, Dong. University of Newcastle; Reino UnidoFil: Barata Vallejo, Sebastian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Orgánica. Cátedra de Química Orgánica I; ArgentinaFil: Golding, Bernard T.. University of Newcastle; Reino UnidoFil: Ferreri, Carla. Consiglio Nazionale delle Ricerche; ItaliaFil: Chatgilialoglu, Chryssostomos. Consiglio Nazionale delle Ricerche; Itali

Biomimetic Models of Radical Stress and Related Biomarkers

The biological consequences of free radical production is the central subject of a very lively scientific debate, focusing on the estimation of the type and extent of damage, as well as the efficiency of the protective and repair systems. When studying free radical based chemical mechanisms, it is very important to establish biomimetic models, which allow the experiments to be performed in a simplified environment, but suitably designed to be in strict connection with cellular conditions. The biomimetic modeling approach has been coupled with physical organic chemistry methodologies and knowledge of free radical reactivity. Molecular basis of important processes have been identified, building up molecular libraries of products concerning unsaturated lipids, sulfur-containing proteins and nucleic acids, to be developed as biomarkers. Ongoing projects in our group deal with lipidomics, genomics and proteomics of free radical stress and some examples will be described

Lipidomics and Free Radical Modifications of Lipids

The free-radical-induced modification of biologically relevant molecules is an active field of interdisciplinary research, spanning from chemistry to biochemistry, biology and medicine. Lipid modifications are also attracting attention for their relationship with structural and functional roles in physiological and pathological conditions of living organisms. The discipline of lipidomics studies the lipid behavior in an innovative and multidisciplinary context. Combining lipidomics with free radical chemistry, the research field becomes an ideal setting for the chemical biology approach, to study the basis of molecular mechanisms and chemical reactivity and connect them with free-radical-based processes occurring in the biological environment. This paper will give an overview of the approaches for studying free radical processes on lipids and some biological consequences, which represent also subjects of interdisciplinary collaborations among European research groups and contribute to the general topic of the COST Action 'Free Radicals in Chemical Biology'