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Interaction of pyridinium bis-retinoid (A2E) with bilayer lipid membranes

Paper ID Volume ID Publish Year Pages File Format Full-Text
31169 44560 2007 9 PDF Available
Title
Interaction of pyridinium bis-retinoid (A2E) with bilayer lipid membranes
Abstract

The accumulation of lipofuscin granules within the retinal pigment epithelium (RPE) cells is correlated with the progression of age-related macular degeneration. One of the fluorophores contained in lipofiscin granules is pyridinium bis-retinoid (A2E). To test its membrane–toxic effect, the interaction of A2E with bilayer lipid membranes (BLM) was studied. The incorporation of charged A2E molecules into the membranes has been detected as a change of either ζ-potential of multilayer liposomes or boundary potential of BLM. It was shown that the presence of up to 25 mol% of A2E did not destabilize the bilayers made of saturated phosphatidylcholine (PC). However, the destabilizing effect became very significant when BLM contained negatively charged lipids such as cardiolipin or phosphatidylserine. The electrical breakdown measurements revealed that the A2E-induced decrease of BLM stability was primarily associated with the growing probability of lipid pore formation.It was found from the measurements of boundary potential of BLM that exposure of A2E to light initiates its transformation into at least two products. One of them is epoxy-A2E, which, being hydrophilic, moves from the membrane into water solution. The other product is a non-identified hydrophobic substance. Illumination of A2E-containing BLM made from unsaturated PC by visible light caused the membrane damage presumably due to oxidation of these lipids by singlet oxygen generated by excited A2E molecules. However, this effect was very weak compared to the effect of known photosensitizers. The illumination of BLM with A2E also leads to the damage of gramicidin incorporated into the membrane, as was detected by measuring the conductance of channels formed by this peptide.

Keywords
Pyridinium bis-retinoid; A2E; Photooxidation; Singlet oxygen; Photosensitizer; Bilayer lipid membrane; Adsorption; Boundary potential; Surface charge; Lipid oxidation; Gramicidin
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Interaction of pyridinium bis-retinoid (A2E) with bilayer lipid membranes
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 86, Issue 2, 1 February 2007, Pages 177–185
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us