Sucrose induces vesicle accumulation and autophagy.
It has been shown that the treatment of mammalian cells with sucrose leads to vacuole accumulation associated with lysosomes and upregulation of lysosomal enzyme expression and activity. Autophagy is an evolutionarily conserved homeostatic process by which cells deliver cytoplasmic material for degradation into lysosomes, thus it is probable that sucrose affects the autophagic activity. The role of sucrose in autophagy is unknown; however, another disaccharide, trehalose has been shown to induce autophagy. In the current study, we used mouse embryonic fibroblasts to investigate whether sucrose induces autophagy and whether vesicle formation is associated with autophagy. The results showed that sucrose induces autophagy while being accumulated within the endosomes/lysosomes. These vesicles were swollen and packed within the cytoplasm. Furthermore, trehalose and the trisaccharide raffinose, which are not hydrolyzed in mammalian cells, increased the rate of vesicles accumulation and LC3-II level (a protein marker of autophagy). However, fructose and maltose did not show the same effects. The correlation between the two processes, vesicle accumulation and autophagy induction, was confirmed by treatment of cells with sucrose plus invertase, or maltose plus acarbose-the α-glucosidase inhibitor-and by sucrose deprivation. Results also showed that vesicle accumulation was not affected by autophagy inhibition. Therefore, the data suggest that sucrose-induced autophagy through accumulation of sucrose-containing vesicles is caused by the absence of hydrolysis enzymes.
Department of Electrical, Engineering and Bioscience, Center for Advanced Biomedical Sciences (TWIns), Waseda University, Tokyo, 162-8480, Japan.
Takahiro
T
Higuchi
Jun
J
Nishikawa
Hiroko
H
Inoue
D000818:Animals; D001343:Autophagy / Q000187:drug effects; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology; D011992:Endosomes / Q000737:chemistry / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D006868:Hydrolysis; D008247:Lysosomes / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011887:Raffinose / Q000494:pharmacology; D013395:Sucrose / Q000493:pharmacokinetics / Q000494:pharmacology*; D014199:Trehalose / Q000494:pharmacology
D008869:Microtubule-Associated Proteins; D013395:Sucrose; D014199:Trehalose; D011887:Raffinose
AUTOPHAGY; SUCROSE; VESICLE ACCUMULATION