Participation Of Glycosphingolipid Biosynthesis In Renal Collecting Duct Cell Differentiation.

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

Pecs, Hungary

Congreso; 48th International Conference on the Biochemistry of Lipids (ICBL).; 2007

ICBL

PO 103Participation of the glycosphingolipidbiosynthesis in the differentiation of renalcollecting duct cellsLucila Pescio, Francisco Leocata-Nieto, Nicol´asFavale, Mar´ıa del Carmen Fernandez-Tom´e,Norma Sterin-SpezialeDepartment of Biological Sciences, University ofBuenos Aires, ArgentinaMDCKis a non-transformed renal collecting cellular linethat conserves the capacity to differentiate in particularconditions of cell culture. To differentiate, collectingduct cells have to acquire a polarized phenotype. Cellpolarization is characterized by the presence of apicaland basolateral membrane domains which differ intheir protein content as well as in lipid composition.While glycosphingolipids (GSL) predominate in the apicalmembrane, sphingomyelin is the major sphingolipidof the basolateral membrane. It has been previouslyreported that extracellular hypertonicity induces cellpolarization/differentiation, but the mechanism involvedis not well understood. In this study, we have examinedthe role of the GSL biosynthesis in the process of collectingduct cell differentiation. Confluent MDCK cellswere submitted to high NaCl concentration (250 mM)for24 and 48 h. Glycosphingolipid metabolism was determinedby using 14C-galactose as radioactive precursor.The cell differentiation was followed by using fluorescentanti gp 135, a marker of apical membrane ofpolarized collecting duct cells, and visualized by confocalfluorescent microscopy. The results demonstrate thatincrease of GSL biosynthesis is an early event inducedby hyperosmolarity which preceded the formation ofapical membrane domain reflected by the apical accumulationof fluorescent gp 135. The pretreatment of cellwith PDMP, a potent inhibitor of glycosyltransferase,evoked a 70% decrease of GSL biosynthesis and inducedthe disappearing of gp 135 accumulation in apical membranedomain. From these results, we conclude that GSLbiosynthesis play a central role in the process of collectingduct cell differentiation.doi:10.1016/j.chemphyslip.2007.06.153