Membrane remodeling induced by lipid photo-oxidation

We investigated how lipid photo-oxidation can affect plasma membrane models represented by giant unilamellar vesicles (GUVs). Here, we compare the effect of methylene blue (MB) photoactivation on lipid bilayers containing POPC:DPPC:Cholesterol (Chol) compared to those containing a hydroperoxide lipid POPC-OOH:DPPC:cholesterol, also comparing the consequence of photoactivation of DO15 in the same membranes contains the same lipids and concentrations that were carried out with the other photosensitizer, affecting the influence of the hydroperoxide and each of the molecules when irradiated. 

Photosensitizers were selected because MB is a hydrophilic molecule, therefore it is preferentially allocated in the aqueous medium, in the system under analysis this will be mostly in the solution around the membrane, while DO15 is a molecule resulting from a change in MB, so which makes it more hydrophobic than MB, therefore it is preferentially located in the middle of the bilayer. Therefore, noise pollution resulting from photo activation of molecules will be generated in different locations. 

 It is interesting to highlight that depending on the concentration of each lipid in the membrane, that is, the proportion, the effects observed using optical and fluorescence microscopy were different. The results obtained in some cases indicated changes in the liquid-ordered (Lo) - liquid-disordered (Ld) phase separation of the membranes and the appearance of micro pores.

This work was supported by Conselho Nac. Des. Cient. Tecnologico (CNPq #126387).