Triglycerol synthesis dynamics under hyperosmolar stress

WEBER, KAREN; CASALI, CECILIA IRENE; PARRA, LEANDRO; . FERNÁNDEZ TOME, MARIA DEL CARMEN

Buenos Aires

Congreso; XLIX Reunión Anual de la Sociedad Argentina de Investigaciones Bioquímicas y Biología Molecular-SAIB; 2013

SAIB

Renal medullary cells are immersed in a hyperosmolar environment due to their function in the urine concentrating system. In order to survive in these conditions, cells must develop protective mechanisms. We showed that the renal papilla is the zone with the highest content and synthesis of phospholipids (PL), which helps to preserve the membrane structure and cell viability. Triglycerides (TG) are a possible source of fatty acids for the synthesis of PL. In this work we study the dynamics of TG and PL synthesis in renal epithelial cells subjected to hyperosmolarity. We studied lipid synthesis in renal medullary slices and in MDCK cells submitted to different hyperosmolar media (from 298 to 579 mOsm/kgH2O) by using different precursors: [U14C]-glycerol, [14C]-arachidonic acid (AA), [14C]-palmitic acid and [3H]-oleic acid. After treatment lipids were extracted, separated by TLC and quantified by liquid scintillation. We observed that high osmolarities increase TG and PL synthesis in all the samples assayed. All precursors were incorporated to both TG and PL molecules except for the AA which was found only in PLs. Cerulenin, a FAS inhibitor used to suppress fatty acid de novo synthesis, decreases TG synthesis and content while PL synthesis remains active. These results show that molecular machinery involved in lipid metabolism is differentially regulated by hyperosmolarity.