Implication Of Sphingosine Kinase In MDCK Cell Transition From Polarized To Differentiated Phenotype

SANTACREU B; STERIN SPEZIALE, NB; FAVALE, NO

Mendoza

Congreso; XLVIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research (SAIB); 2012

SAIB

We have demonstrated that sphingolipid biosynthesis is essential for hypertonicity-induced MDCK cell differentiation. Sphingolipids regulates several aspects of cell behavior, being sphingosine 1-phosphate (S1P) one of most important. Thus, we study the importance of S1P synthesis in the acquisition of the polarized-differentiated MDCK cell phenotype. In epithelial cell polarization/differentiation transition, cell-cell adhesion is an early event characterized by the establishment of adherents junctions.To evaluate the importance of S1P in this process, confluent MDCK cells were subjected to hypertonicity and concomitantly treated or not (control) with different concentrations of D-threodihydrosphingosine (Sphingosine Kinase inhibitor). After 48 h,cell phenotype was visualized by fluorescence microscopy of actin cytoskeleton and cell-cell adhesion structures (E-Cadherin, ßcatenin and a-catenin). As inhibitor concentration rise the cell-cell adhesions were impaired, and the characteristic polarized phenotype of the cells was lost. First, cells appeared lengthened, and thereafter acquired a fibroblast-like phenotype. Interestingly,ß-catenin suffered redistribution from plasmatic membrane to cytoplasmic and nuclear localization. In the present work we demonstrate that SK activity is essential in the MDCK cell differentiation process induced by hypertonic stress.