Artificial plasma membrane models based on lipidomic profiling.

Phospholipid monolayers are often described as membrane models for analyzing drug-lipid interactions. In many works, a single phosphatidylcholine is chosen, sometimes with one or two additional components. Drug penetration is studied at 30mN/m, a surface pressure considered as corresponding to the pressure in bilayers, independently of the density of lipid molecular packing. In this work, we have extracted, identified, and quantified the major lipids constituting the lipidome of plasma and mitochondrial membranes of retinoblastoma (Y79) and retinal pigment epithelium cells (ARPE-19), using liquid chromatography coupled to high-resolution mass spectrometry (LC-MS/MS). The results obtained from this lipidomic analysis were used in an attempt to build an artificial lipid monolayer with a composition mimicking that of the plasma membrane of Y79 cells, better than a single phospholipid. The variety and number of lipid classes and species in cell extracts monolayers exceeding by far those of the phospholipids chosen to mimic them, the π-A isotherms of model monolayers differed from those of lipid extracts in shape and apparent packing density. We propose a model monolayer based on the most abundant species identified in the extracts, with a surface compressional modulus at 30mN/m close to the one of the lipid extracts.

Assessment of the relevance of supported planar bilayers for modeling specific interactions between glycodendrimeric porphyrins and retinoblastoma cells.

Glycodendrimeric porphyrins seem promising photosensitizers usable in photodynamic therapy. Evidence of their ability to interact with an artificial supported bilayer membrane exhibiting a model sugar receptor has been previously shown. In the present work, the interaction of the glycodendrimeric porphyrins with retinoblastoma cells bearing the actual sugar receptor has been assessed by both classical cell cultures and an original approach using the quartz crystal microbalance (QCM-D). Our results showed that unlike cell cultures, QCM-D allowed analyzing the mechanism of interaction of the glycodendrimeric porphyrins with the sugar receptor. Not only was molecular recognition demonstrated, but our methodology also proved efficient to discriminate between the studied compounds, depending on the presence of carbohydrate, and the spacer length.