SPHINGOMYELIN SYNTHESIS IS INVOLVES IN DE-DIFFERENTIATION PROCESS IN MDCK CELLS

FAVALE NO; SANTACREU BJ; UDOVIN LD; MARQUEZ MG, STERIN DE SPEZIALE NB

Mar del Plata

Congreso; Reunión de la sociedad argentina de investigaciones en bioquímica y biología molecular (SAIB), Mar del Plata, 3-6 Noviembre 2015. Supplement BIOCELL, volumen 39 (supl 2015); 2015

We have previously demonstrated that sphingomyelin (SM) biosynthesis is essential for hypertonicity-induced MDCK cell differentiation. Under inhibition of SM synthesis, MDCK cells instead to differentiate switch to mesenchymal phenotype thus performing an epithelial to mesenchymal transition (EMT). We aim to study the sphingolipid metabolic pathway as well as the sphingomyelin synthase (SMS) isoform involved in such process. Confluent MDCK cells were subjected to hypertonicity and concomitantly SMS was inhibited by pharmacological and knockdown strategies (D609 and siRNA-SMS1). Both strategies showed alteration of polarized phenotype with acquisition of mesenchymal phenotype. The phenotype alteration was accompanied with alteration in plasma membrane SM distribution, suggesting an alteration in cell polarization. To evaluate the EMT, different markers was performed. The results showed an increase in mesenchymal marker, citoskeleton reorganization and loss of the epithelial marker, particularly the kidney specific cadherin-16. Moreover, SM inhibition induced an increase in lectin BSL-1 expression (mesenchymal marker) and a decrease in lectin DBA (collecting duct cell marker). It has been reported that these cell could suffer a trans-differentiation to myofibroblast, however, no increase in alpha-smooth muscle actin was observed in our model. These results suggest that the inhibition of SM synthesis induces the de-differentiation of MDCK, thus suggesting the implication of SM in EMT