LOCALIZATION AND NICOTINE MODULATION OF ALPHA7-ACETYLCHOLINE RECEPTOR IN HUMAN ENDOTHELIAL CELLS

AYALA PEÑA V.B.; BONINI I.C.; BARRANTES F.J.

Tucumán Argentina

Congreso; SAIB 2009; 2009

LOCALIZATION AND NICOTINE MODULATION  OF ALPHA7-ACETYLCHOLINE RECEPTOR IN HUMAN ENDOTHELIAL CELLS Ayala Peña VB, Bonini IC, Barrantes FJ. UNESCO Chair Biophys. & Mol. Neurobiology-INIBIBB, Bahía Blanca, Argentina E-mail: vayala@criba.edu.ar   The α7-type neuronal nicotinic acetylcholine receptor (α7-AChR) is abundant in the central nervous system, though it also occurs in non-nervous tissues. Characterizing the role of α7-AChR in angiogenesis and in endothelial pathology is key to understanding the molecular and cellular basis of tobacco-related diseases. We studied the effect of nicotine on α7-AChR expression in the human umbilical vein cell line HUVEC by fluorescence microscopy. Cell-surface fluorescence of Alexa 488α-BTX-tagged α7-AChR varied in a time- and ligand-dependent manner. In order to determine whether α7-AChR occurred in ordered lipid domains (?rafts?), plasmalemma?enriched fractions were prepared by subcellular fractionation and resolved into detergent-soluble and detergent-insoluble fractions, and the distribution of α7-AChR analyzed by immunoblotting and binding studies. Trace amounts of α7-AChR were found in control HUVEC, increasing up to ~700% upon nicotine (50 μM) treatment. No differences were apparent between detergent-extracted fractions. Cholesterol depletion from endothelial cells was found to have little if any effect per se on the kinetics of wound repair mediated by cell migration. Nicotine alone enhanced the ability of cells to repair the mechanical wound. This ?positive? effect of nicotine on would repair was drastically impaired in cells deprived of cholesterol.