MODULATION OF CAV2.1 CHANNELS BY CHOLESTEROL LEVELS

WEISSMANN C; BOSCO ACKERMAN B; URBANO FJ; UCHITEL OD

Chicago, USA

Congreso; 2014 Society for Neuroscience Chicago Chapter, Annual Scientific Meeting Northwestern Memorial Hospital April 4, 2014; 2014

2014 Society for Neuroscience Chicago Chapter

Calcium channels (CaV) show different compartmentalization on neuronal plasma membranes where they form clusters, involving both cytoskeletal elements and microdomains within the lipid bilayer. CaV2.1 channels are distributed in lipid microdomains.We showed an acute effect of pregabalin (PGB, a alpha2delta-binding drug) on the cellular function and distribution of CaV2.1 channels transfected in HEK293t. The system allowed us to visualize the internalization of subunits within cells after PGB treatment by means of fluorescence microscopy, while recording barium-mediated currents (IBa). We studied how the cytoskeleton and the lipid rafts organization might modulate the calcium channels. For this purpose, we treated transfected cells with methyl-cyclodextrin (MbetaCD, 5-10 min.), a cholesterol sequestering drug, and determined the internalization of the fluorescent subunits, and the distribution of microtubules. MbetaCD (10 mM, 10-20min) increased α1 internalization (with a membrane/interior ratio 10% lower compared to untreated cells) and reduced IBa. Moreover, addition of cholesterol (10 mM, 10min) to the membrane decreased the currents. In addition, MbetaCD and PGB exerted an effect on the microtubule cytoarchitecture evidenced by a diffuse tubulin staining. The implications on the importance of this modulation lies on the fact that lipids change in the aged brain which could in turn modulate the levels of functional channels at the plasma membrane.