Sucrose induces vesicle accumulation and autophagy

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Mammalian cells treated with sucrose exhibit vacuole accumulation and increased lysosomal enzyme activity.
• Autophagy, a cellular degradation process, involves delivering cytoplasmic material to lysosomes.
• Trehalose, a disaccharide, is known to induce autophagy in cells.

Purpose of the Study:

• To investigate whether sucrose induces autophagy in mammalian cells.
• To determine if vesicle formation is associated with sucrose-induced autophagy.
• To explore the role of hydrolysis enzymes in sucrose's effect on autophagy.

Main Methods:

• Treatment of mouse embryonic fibroblasts with sucrose, trehalose, raffinose, fructose, and maltose.
• Analysis of vesicle accumulation within endosomes/lysosomes.
• Measurement of LC3-II levels as a marker for autophagy.
• Confirmation of correlation using enzyme treatments (invertase, α-glucosidase inhibitor) and sucrose deprivation.
• Assessment of vesicle accumulation under autophagy inhibition.

Main Results:

• Sucrose induces autophagy and accumulates within endosomes/lysosomes, forming swollen vesicles.
• Trehalose and raffinose also increased vesicle accumulation and LC3-II levels, unlike fructose and maltose.
• Vesicle accumulation and autophagy induction showed a strong correlation, independent of autophagy inhibition.

Conclusions:

• Sucrose induces autophagy via the accumulation of sucrose-containing vesicles in lysosomes.
• The observed effect is attributed to the absence of specific hydrolysis enzymes for sucrose in mammalian cells.
• This study elucidates a novel mechanism of sucrose-induced autophagy related to lysosomal processing.