earticle

영어

Autophagy is conserved response to starvation by which cells catabolize their components to create an internal supply of essential nutrients. Ceramide is known to induce autophagy in many cells through down-regulation of amino acid and glucose transporters. The mechanism of starvation induced-autophagy in mouse embryo remains unclear. In order to understand the mechanism by which starvation regulates autophagy, in this study, we investigated nutrient transporters expression and the effect of c2-ceramide on the in vitro development, apoptosis and autophagy via starvation in mouse embryo. Glucose transporters (Glut1 and Glut 3), high levels of transcript were expressed from 1 to 2 cells and gradually decreased through the morula and blastocyst (BL) stages. Amino acid transporters (LAT-1 and 4F2hc) gradually decreased from the zygote to the BL stage. Furthermore, the expression of nutrient transporters (Glut1, 3, LAT-1 and 4F2hc) were significantly reduced at the BL stage after ceramide treatment. Especially, mTOR expression after ceramide treatment of embryos was significantly higher than controls. Ceramide treated embryos exhibited significantly reduced developmental rates and total cell numbers, and increased apoptotic cell death at the BL stage. Consequently, we next evaluated the effect of ceramide treatment on mitochondrial number and morphology. There was a significant decrease in the average mtDNA copy number and the mitochondrial area in ceramide treated BL stage embryos. Both the expression of autophagy-related genes, Lc3, Gabarap, Atg4A and Atg4B, and the synthesis of LC3 were significantly induced at the BL stage. These results suggest that autophagy under starvation condition influences the in vitro development and apoptosis and autophagy, and may play a role in early mouse embryogenesis.