Lyso- and omega-3-containing phosphatidylcholines alter the bending elasticity of lipid membranes

We report on the effect of lyso- and polyunsaturated fatty acid (PUFA)-containing lipids on the bending elastic properties of lipid membranes. The bending stiffness of monounsaturated phosphatidylcholine (POPC) bilayers with various molar fractions of an omega-3-containing phosphatidylcholine (PDPC) and/or a lysophosphatidylcholine (lyso-PC) was measured by thermal shape fluctuation analysis (TSFA) performed on quasispherical giant unilamellar vesicles (GUV). Strong evidences of their softening effect on lipid bilayers are provided together with data suggesting different degree of influence of the two molecules on the membrane bending elasticity. The effect of lyso-PC on the bending stiffness of POPC membranes was shown to be stronger than the PDPC. We conclude that the PDPC and lyso-PC are most likely controlling the membrane deformations by modulating its elastic properties.