On the permeability of cell membranes subjected to lipid oxidation

Abstract

AbstractThe formation of transient hydrophilic pores in their membranes is a well-recognized mechanism of permeabilization of cells exposed to high-intensity electric pulses. However, the formation of such pores alone is not able to explain all aspects of the so-called electroporation phenomenon. In particular, the reasons for the sustained permeability of cell membranes, which persist long after the pulses’ application, remain elusive. The complete resealing of the cell membranes takes indeed orders of magnitude longer than the time of electropore closure as reported from molecular modelling investigations. A possible alternative mechanism to explain the observed long-lived permeability of cell membranes, lipid peroxidation, has been previously suggested but the theoretical investigations of membrane lesions, containing excess amounts of hydroperoxides, have shown that the conductivities of such lesions were not high enough to reasonably explain the entire range of experimental measurements. Here, we expand on these studies and investigate the permeability of cell membrane lesions that underwent secondary oxidation. Molecular dynamics simulations and free energy calculations on lipid bilayers in different states show that such lesions provide a better model for post-pulsed permeable and conductive electropermeabilized cells. These results are further discussed in context of sonoporation and ferroptosis, respectively a procedure and a phenomena, among others, in which alike electroporation substantial lipid oxidation might be triggered.HighlightsThe contribution of secondary lipids’ oxidation to the permeabilization of model membranes is quantitatively assessedSmall patches of secondary lipids’ oxidation cause formation long-lived pores in lipid bilayers.The cholesterol content of membranes enhances the life-time of the formed pores.A single pore accounts for the measured post-pulse electropermeabilization of cells.The diffusion of the secondary oxidation lipids, even after pores closure leads to permeability of lipid membrane.