Osmotic regulation of lipid metabolism in renal epithelial cells.

WEBER, KAREN; CASALI, CECILIA IRENE; GOMEZ MOREL, EMANUEL; FAGGIONATO, DANIELA; MIKKELSEN, EVELYN; FERNANDEZ TOME, MARIA DEL CARMEN

San Luis

Congreso; SAIB; 2011

SAIB

Due to the urine concentration mechanism, the renal papillary interstitium has the highest osmolality of the body. To survive and work in such harmful environment, renal cells have protective mechanisms. We showed that papillary cells possess the highest phospholipid (PL) synthesis and turnover of the kidney, which contribute to preserve membrane homeostasis and cell viability. We also showed that renal phospholipid metabolism is regulated by osmolarity. Considering that PL synthesis require an adequate supply of fatty acids, in this work we characterized the relationship between PL and triacylglycerol (TG) in renal cells.The levels of PL and TG were determined in the different zones of the kidney and in cultures of the renal cell line MDCK grown during 24, 48, 72 and 96 h in media with osmolalities from 298 to 570 mOsm/kgH2O. Renal cortex (isosmolarity) showed the highest PL content but the lowest TG content and PL synthesis. In opposite, papilla showed the lowest PL content but the highest TG content and PL synthesis. In MDCK cells, we found that hyperosmolarity significantly increases PL and TG content. Such increase is dependent on the time of incubation and the osmolarity of the medium. These results demonstrate the relationship between renal PL synthesis and TG content and the role of environmental osmolarity as a distinctive regulatory factor of renal lipid metabolism.