Changes in environmental osmolality regulate lipid metabolism in renal epithelial cells.

WEBER, KAREN; CASALI, CECILIA IRENE; MESSINGER, DAIANA; FAGGIONATO, DANIELA; MIKKELSEN, EVELYN; FERNANDEZ , MARIA DEL CARMEN

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Bioquímica y Biología Molecular; 2012

SAIB

Cells in the renal papilla, due to their function in concentrating urine, are surrounded by high osmolalities. To survive in these adverse conditions, they have protective mechanisms. We showed that renal papilla is the kidney zone that has the highest synthesis and phospholipid (PL) turnover, and that this helps to preserve the membrane structure and thus cell viability. As PL synthesis requires an adequate supply of fatty acids, here we evaluate the levels of triacylglycerides (TG) and their relationship with PLs in the different kidney zones and in MDCK cells submitted to osmolalities ranging 298-579 mOsm/kg H2O. Lipids were separated by TLC and quantified. Also we studied the expression of several enzymes involved in the synthesis of PL and TG by RT-PCR. We observed that renal cortex has the highest content of PL but the lowest of TG and PL synthesis. In contrast, renal papilla has the lowest content of PL but the highest of TG and PL synthesis. In MDCK, hyperosmolality significantly increases PL and TG content in a time and concentration dependent manner. Hyperosmolality also increases the expression of PL and TG enzymes. TGs are stored in lipid droplets, so we evaluated their size and number by Oil-Red-O staining in MDCK, observing that they both increase in hyperosmolality. These data show that changes in environmental osmolality regulate PL and TG metabolism in renal cells.