Participation of glycosphingolipid biosynthesis in renal collecting duct cell differentiation

PESCIO L; LEOCATA NIETO F; FAVALE NO; FERNANDEZ-TOME MC; STERIN-SPEZIALE N

Mar del Plata , Buenos Aires, Argentina

Congreso; XLIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2007

SAIB

PARTICIPATION OF GLYCOSPHINGOLIPID BIOSYNTHESIS IN RENAL COLLECTING DUCT CELL DIFFERENTIATION Pescio 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.ar MDCK is a renal collecting duct cellular line that conserves the capacity to differentiate in particular conditions of cell culture. To differentiate, they acquire a polarized phenotype characterized by the presence of apical and basolateral membrane domains with different protein and lipid composition. Glycosphingolipids (GSL) predominate in the apical membrane. It has been previously reported that extracellular hypertonicity induces cell differentiation, but the mechanism involved is not well understood. In this study, we have examined the role of GSL biosynthesis in collecting duct cell differentiation. Confluent MDCK cells were submitted to 300 mM NaCl for 24 and 48h. Glycosphingolipid metabolism was determined by using C-galactose as radioactive precursor and cell differentiation was followed by using fluorescent anti gp135, a marker of apical membrane, and visualized by confocal fluorescent microscopy. The results demonstrate that hypertonicity induced an early increase in GSL biosynthesis and the formation of apical membrane domain reflected by the apical accumulation of gp135. The pretreatment with PDMP, an inhibitor of Glucosylceramide synthase, evoked a 70% decrease in GSL biosynthesis and induced the disappearing of gp135 accumulation in apical membrane domain. From these results we conclude that GSLbiosynthesis play a central role inMDCKcells differentiation.