Controlled human RBC modifications affecting the binding of cationic liposomes
Di Giulio, A.; Oratore, A.; Tozzi-Ciancarelli, M.G.; Crifo', C.; Finazzi-Agro', A.
Biochemistry International 16(6): 999-1007
1988
ISSN/ISBN: 0158-5231 PMID: 3178866 Document Number: 321974
Cationic liposomes were prepared either by sonication or by detergent dialysis and used to deliver the antioxidative enzyme glutathione peroxidase into human erythrocytes in vitro. The enrichment ability of these two preparations was similar, amounting to about 30% of the control cells. The lysis of enzyme-treated erythrocytes induced by photoirradiation in the presence of PPIX was compared with that of cells incubated with empty liposomes. Erythrocytes enriched with GPX appear to be more resistant toward photohemolysis. Pre-treatment of cells with neuraminidase or proteinase K suggests that: a) sialic acid seems to be essential for the cell-liposome fusion process, no enrichment being found which the neuraminidase-treated cells; b) hydrolysis of the outer membrane proteins leads to an increased fragility with respect to controls even in GPX-enriched cells. These results were confirmed by extrinsic fluorescence polarization experiments, using isolated erythrocyte membranes and specific fluorescent probes.