PARTICIPATION OF GLYCOSPHINGOLIPID

LUCILA G. PESCIO; FRANCISCO LEOCATA NIETO; NICOLÁS O. FAVALE; MARÍA C. FERNÁNDEZ; NORMA B. STERIN-SPEZIALE

Mar del Plata

Congreso; Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

SAIB

PARTICIPATION OF GLYCOSPHINGOLIPIDBIOSYNTHESIS IN RENAL COLLECTING DUCT CELLDIFFERENTIATIONPescio L, Leocata Nieto F, Favale N, Fernandez-Tomé MC, Sterin-Speziale N.Biología Celular. FFyB, UBA. IQUIFIB-CONICET. Buenos Aires,Argentina. E-mail: lucilagpescio@yahoo.com.arMDCK is a renal collecting duct cellular line that conserves thecapacity to differentiate in particular conditions of cell culture. Todifferentiate, they acquire a polarized phenotype characterized bythe presence of apical and basolateral membrane domains withdifferent protein and lipid composition. Glycosphingolipids (GSL)predominate in the apical membrane. It has been previously reportedthat extracellular hypertonicity induces cell differentiation, but themechanism involved is not well understood. In this study, we haveexamined the role of GSL biosynthesis in collecting duct celldifferentiation. Confluent MDCK cells were submitted to 300 mMNaCl for 24 and 48h. Glycosphingolipid metabolism wasdetermined by using C-galactose as radioactive precursor and celldifferentiation was followed by using fluorescent anti gp135, amarker of apical membrane, and visualized by confocal fluorescentmicroscopy. The results demonstrate that hypertonicity induced anearly increase in GSL biosynthesis and the formation of apicalmembrane domain reflected by the apical accumulation of gp135.The pretreatment with PDMP, an inhibitor of Glucosylceramidesynthase, evoked a 70% decrease in GSL biosynthesis and inducedthe disappearing of gp135 accumulation in apical membranedomain. From these results we conclude that GSLbiosynthesis playa central role inMDCKcells differentiation.