Inhibition of sphingomyelin synthesis causes a return to the initial stage of epithelial tissue

YAMILA ROMINA BRANDÁN; EDITH DEL VALLE GUAYTIMA; LUCILA GISEL PESCIO; NICOLÁS OCTAVIO FAVALE; NORMA B. STERIN-SPEZIALE; MARÍA GABRIELA MÁRQUEZ

Mar del Plata, Buenos Aires

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Previously, we showed that adherens junctions (AJ) and focal adhesions (FA) are located in membrane lipid domains rich in sphingomyelin (SM), and inhibition of SM synthase 1 mediated SM synthesis altered cell-cell adhesion. Now, we investigated the reversibility of this alteration, and the effect of the inhibition of SM synthesis on FA and actin cytoskeleton. To this end, 48 hs-old primary cultures of rat renal papillary collecting duct cells were incubated for 24 hs with D609, a SM synthase1 inhibitor. When cultured cells were treated with increasing concentrations of D609, the typical epithelial sheet was highly altered, accompanied with changes in the actin cortex and stress fibers remodeling, but cells dettachment was not observed. D609 induced a raise in the number of vinculin- and talin-stained-FA. Although D609 evoked loss of cell-cell adhesion no alteration on the amount of AJ proteins ocurred as denoted by Western blot, so the loss of cell-cell adhesion could be due to deficient protein delivery. AJ impairment appear to be reversible since cell-cell adhesion restoration was observed after reincubation in the absence of D609 for 24 hs.These results suggest that the inhibition of SM synthesis would cause a return to the initial stage of organization of epithelial tissue that is the formation of FA in order to maintain the cells attached to the matrix and thus remain viable.