engleski

AFM and force spectroscopy studies on the interaction of myricetin and myricitrin with model and biological cell membranes

Interactions of flavonoids with the plasma membranes and cells exposed to the oxidative stress are not clearly understood with the respect to their influence on the membrane structure, elasticity and its functionality, especially regarding lipid ordering and phase behavior. Aim of this research is to study flavonoid interactions with model lipid membranes and P19 neurons in vitro. Flavonoids exert various biological activities [1], among which anticarcinogenic [2], antiinflammatory [3] and antibacterial [4] activity. Their main characteristic is potent antioxidant activity, higher than that of other well-known antioxidant molecules [5]. Myricetin exhibits anti-tumor and anti-inflammatory effects, strong scavenging activity [6] and more potent neuroprotective action than other compounds [7]. Myricitrin reportedly possesses effective anti-oxidative, anti-inflammatory and anti- nociceptive activities and can protect a variety of cells from stress, in vitro and in vivo [8]. Myricetin and myricitrin are flavonoids chosen to work with in order to test their ability to inhibit lipid oxidation in model membranes and in neurons in vitro, and quercetin is used as a positive control. The mechanisms of interactions were investigated on two different systems. First directly on model membranes made of a lipid mixture with unsaturated phosphatidylcholine, sphinogomyelin and cholesterol (PC/SM/Chol) and also on biological membranes of P19 neurons. The use of model membrane systems was motivated by the necessity for easier deduction of the critical role that membrane lipids have in cellular uptake and to study the details of flavonoid incorporation and activity. The new aspect of this study showed that the local membrane structural reorganization is induced by peroxidation. This was achieved with combining AFM imaging data and force spectroscopy (FS). The altered structural and mechanical properties of neuronal membranes exposed to stress, as well as the changes within the cytoplasm, cell nucleus, and particularly cytoskeleton components are recorded. This study highlights the potential of AFM imaging and FS in elucidating the mechanism of flavonoids directly in the plasma membrane and in the cytoplasm. The nanomechanics (elasticity), spatial organization (organization of the domains) and surface topography (roughness) of model lipid membranes and P19 neurons as well as the structural reorganization within the cytoplasm (cell morphology, viability) that result from the oxidative damage are quantified by AFM for the first time. References [1] D.V. Ratnam et al. J. Control. Release 113 189 (2006) [2] I. L. Martins et al. J. Med. Chem. 58 4250(2015) [3] M.M. Li et al. J. Nat. Prod. 77 2248 (2014) [4] R. Hendra et al. Int. J. Mol. Sci. 12 3422 (2011). [5 ] N. Nuengchamnong et al. Naresuan Univ. J. 12 25(2004) [6] Choi Seon-Min et al. Chonnam. Med. J. 50 45(2014) [7] J. G. Cho et al. J. Agric. Food. Chem. 61 10354 (2013) [8] R. Domitrović et al. Chem.-Biolog. Interac. 230 21(20

AFM; flavonoids; force spectroscopy; lipid oxidation; model membranes; neurons

nije evidentirano