Implication of sphingolipid metabolism in renal epithelial cell line differentiation

SANTACREU B; STERIN SPEZIALE NB; FAVALE NO

Ciudad de Buenos Aires

Congreso; XLIX Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research (SAIB); 2013

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Sphingosine 1-Phophate (S1P) is an important sphingolipid mediator in cell fate, synthetized by Sphingosine Kinase (SK). We study the involvement of SK activity in the establishment of differentiated phenotype of MDCK cells induced by external hypertonic media. For this end, confluent MDCK cells were subjected to hypertonic medium with the concomitant addition or not (control) of D,L-threo-dihydrosphingosine (DHS) as an SK inhibitor. After 48 h of incubation, the cell phenotype was visualized by fluorescence microscopy, evaluating actin cytoskeleton and Adherens Junction (AJ) formation. DHS treatment induces β-catenin redistribution from plasma membrane to intracellular localization and actin cytoskeleton reorganization, resulting in disassembling of AJ. SK inhibition also induces an increase in de novo sphingolipid synthesis with Ceramide (Cer) accumulation. In order to evaluate whether AJ disassembly is due to Cer accumulation, Myriocin (Myr), an inhibitor of the novo synthesis, was used. Myr treatment recovers MDCK phenotype, suggesting that the disassembly of AJ due to inhibition of SK activity is an indirect effect produced by Cer accumulation.