P0038WATER RESTRICTION INDUCES THE SHORTENING OF PRIMARY CILIA IN KIDNEY TUBULAR CELLS

Abstract Background and Aims The primary cilia play a key role in the maintenance of cell homeostasis by sensing and transducing extracellular signals into the cell and are associated with several kidney diseases including ADPKD. Here, we investigated whether water restriction affects the length of primary cilia of kidney tubule cells and its underlying mechanisms. Method Some mice were not supplied with water for 2 days and then the length of primary cilia were determined by immunostaining using acetylated-α-tubulin (ac-α-tubulin) antibody. Madin-Darby canine kidney (MDCK) cells were exposed to high concentration of NaCl or mannitol and the lengths of primary cilia were determined under microscope. Results Water restriction shortened primary cilia length in kidney tubular cells along with the increase of urine osmolality. Water restriction lowered the expression of acetylated-α-tubulin (ac-α-tubulin), EXOC5, one of the components of exocyst complex, and α-tubulin transferase in the kidney. In MDCK cells, high concentration of NaCl or mannitol treatments shortened primary cilia length and decreased the expression of ac-α-tubulin, EXOC5, and α-tubulin transferase. Conclusion These findings demonstrate that water restriction induces the shortening of primary ciliua in kidney tubule cells along with increased urine osmolality, suggesting that primary cilia are involved in the urine concentric process.