Protective effects of a synthesized butyrolactone derivative against chloroquine-induced autophagic vesicle accumulation and the disturbance of mitochondrial membrane potential and Na+,K+-ATPase activity in vascular endothelial cells.

We previously found a butyrolactone derivative, 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one (3BDO), could inhibit vascular endothelial cell (VEC) apoptosis and senescence induced by a deprivation of serum and FGF-2. In this study, we aimed to investigate its actions in VEC autophagy induced by chloroquine (CQ). The measurement on the volume of acidic compartments (VAC) and autophagy analysis by acridine orange (AO) staining and microtubule-associated protein 1 light chain 3 (MAP1LC3) process revealed that 3BDO was an effective inhibitor of autophagic vesicle accumulation (vacuolation) induced by CQ in VECs. 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) was used for mitochondrial membrane potential (MMP) measurement. The results showed that CQ elevated MMP significantly and that 3BDO could significantly inhibit CQ-induced MMP increase. Na+,K+-ATPase activity assay showed that CQ inhibited this enzyme activity significantly and that 3BDO attenuated the alteration of Na+,K+-ATPase activity caused by CQ. We concluded that 3BDO was a promising inhibitor of CQ-induced accumulation of autophagic vesicles in VECs and could weaken the alterations of MMP and Na+,K+-ATPase activity induced by CQ. The data indicate that 3BDO will be a potential tool for investigating the mechanism of autophagy.