Membrane organization and regulation of cellular Cholesterol homeostasis

JAUREGUIBERRY, M. S.; TRICERRI, M. A.; SANCHEZ, S. A.; GARDA, H. A.; FINARELLI, G. S.; GONZALEZ, M. C.; RIMOLDI. O. J.

JOURNAL OF MEMBRANE BIOLOGY

SPRINGER

Lugar: New York; Año: 2010 vol. 234 p. 183 - 194

0022-2631

An excess of intracellular free Cholesterol (Chol) is cytotoxic, and its homeostasis is crucial for cell viability. Apolipoprotein A-I (apoA-I) is a highly efficient Chol acceptor as it activates complex cellular pathways that tend to mobilize and export Chol from cellular depots. Here we hypothesize that membrane composition and/or organization is strongly involved in Chol homeostasis. To test this hypothesis, we constructed a cell line over expressing Stearoyl CoA desaturase (SCD-cells), which modifies plasma membrane (PM) composition by the enrichment of monounsaturated fatty,acids and determined this effect on membrane properties, cell viability and cholesterol homeostasis. PM in SCD-cells has a higher phospholipids/sphingomyelin ratio and is slightly enriched in Chol. These cells showed an increase in the cholesteryl esters/free Chol ratio, they were more resistant to Chol toxicity and in addition, they exported more caveolin than Control cells. The data suggest that cell functionality is preserved by regulating membrane fluidity and Chol exportation and storage