Changes in ceramide metabolism contribute to MDCK cell differentiation

LUCILA G PESCIO; VANINA G. LOPEZ; MONICA GISELA GERARDI; NICOLÁS O. FAVALE; BRUNO J SANTACREU; NORMA B. STERIN-SPEZIALE

Ciudad de Buenos Aires

Congreso; SAIB 2013; 2013

Ceramide (Cer) and Glucosylceramide (GlcCer) are involved in many important cellular processes. We have previously demonstrated that GlcCer derived from recycled Cer is essential in MDCK cell differentiation induced by hypertonicity. Cer species are synthesized by six Cer synthases (CerS1-6), each one with different acyl CoA specificity. The aim of this study was to evaluate the expression of CerS1-6, and the different species of Cer and GlcCer during MDCK cell differentiation. Confluent MDCK cells were cultured under isotonicity or subjected to hypertonic media. RT-PCR analyses showed that MDCK cells express CerS2, CerS4 and CerS6 in both experimental conditions. We analyzed the fatty acid composition of Cer and GlcCer species by MALDI-TOF MS. We identified four mayor species of Cer (C16:0, C24:1, C24:0 and C22:0) and six mayor species of GlcCer (C16:0, C24:1, C24:0, C22:0, C20:0 and C18:0). These results are in accordance with the profile of CerS expression detected. Although the composition of sphingolipids was qualitatively the same under both conditions, we found that C16:0 GlcCer have the highest relative intensity in control cells, whereas hypertonicity-cultured cells showed an increase in the relative intensity in C24:0 GlcCer. These changes in Cer metabolism of MDCK cells could provide new clues to understanding the mechanism of renal epithelial cell differentiation.