SPHINGOMYELIN METABOLISM IS INVOLVED IN THE MAINTENANCE OF TISSUE ORGANIZATION OF COLLECTING DUCTS

BRANDAN YR; GUAYTIMA E; FAVALE NO; PESCIO LG; STERIN-SPEZIALE NB; MARQUEZ MG

Rosario

Congreso; Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research; 2014

SAIB

Adherens junctions (AJ) and focal adhesions (FA) are structures that mediate tissue organization at two different levels. Vinculin is a cytoskeletal protein associated with both structures, interacting with a-catenin through specific domains recruits F-actin to the AJs. Taking into account that we have demonstrated that both adhesion structures are located in sphingomyelin (SM) enriched membrane microdomain, we investigated the influence of SM synthesis in AJ and FA integrity. To this end, primary culture of differentiated collecting duct cells that preserve the fully epithelial phenotype reflected by the presence of primary cilium was incubated for 24 hs with increasing concentration of D609, a SM synthase1 inhibitor. Cell adhesion structures were analyzed by confocal immunofluorescence with anti vinculin and anti a-catenin. We observed a population of cells located in the middle of the colony without FA but with their borders delineated by both proteins, and other more peripheral containing FA. D609 treatment showed cells with irregular shape and a progressive alteration in the distribution of both proteins, denoting AJ impairment. At higher D609 concentration, cell-cell contact was lost but retained the spread morphology by increasing the amount of FA. These results suggest that the activity of SM synthase1 is essential for the maintenance of collecting duct tissue organization.