Различие влияния липополисахарида E. coli , олеиновой кислоты и этомоксира на экспрессию белка ADRP в эпителиальных клетках

Abstract

Intracellularly neutral lipids are deposited in lipid bodies (LB) – special organelles composed of triglyceride or cholesterol esters core surrounded by a phospholipid monolayer. LBs play a central role in cellular lipid metabolism. The biogenesis of LB and consumption of neutral lipids are controlled by proteins of the PAT family, which are expressed on the surface of LB and regulate lipids storage and degradation providing the interaction of LB with mitochondria and access of lipases to their substrates. The ADRP (adipose differentiation-related protein), a member of the PAT family, is a quantitatively major LB surface protein expressed in many cell types. The goal of the present work was to study the involvement of ADRP in the formation of LB and intracellular TAG accumulation under the action of different stimuli –lipopolysaccharide (LPS), exogenous oleic acid and etomoxir, an inhibitor of carnitine-palmitoyltransferase 1. The experiments were performed on epithelial cells isolated from the mucosal surface of the frog urinary bladder. Incubation of the cells for 21 hours with E. coli LPS (25 μg / ml), oleic acid (50 μM) and etomoxir (100 μM) led to a significant increase in the number and size of LBs and an increase in intracellular TAG accumulation. Despite the fact that all the substances used effectively stimulated LB growth, only incubation with LPS was accompanied by a sharp increase in the expression of ADRP protein, whereas in the presence of etomoxir or oleic acid the expression of this protein did not change. The obtained results indicate that the molecular mechanisms underlying the increase in LB formation and TAG accumulation under the action of different stimuli in the same cell type can be differed in relation to the involvement of LB surface proteins.