Purchase this article with an account.
J. V. Ferreira, H. Girao, P. Pereira; Activation of Autophagy Induced By 7-ketocholesterol in Lens Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2009;50(13):4374.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Autophagy is the process by which proteins and subcellular organelles are delivered to the lysosome for degradation and is activated by several stress stimuli. It is currently considered a pro-survival mechanism that can degenerate in cell death upon chronic activation. It has been reported that autophagy doesn’t have a role in lens differentiation. Our aim is to show that 7-ketocholesterol, a cholesterol oxide, can activate macroautophagy in lens epithelial cells.
SRA cells where incubated with 7-Ketocholesterol or 25-hydroxycholesterol (20 ug/ml) for 6 or 12 h, or maintained in nutrient deprivation for 12h. For Macroautophagy assessment cells were transfected with EGFP-LC3 plasmid. Autophagic vesicle formation was assessed by confocal microscopy. LC3 processing was measured by western blot with antibodies against GFP. Akt and p-Akt levels where accessed by western blot with specific antibodies.
7-Ketocholesterol induces the formation of autophagic vesicles and the processing of the LC3-I into LC3-II, both hallmarks of Macroautophagy, an effected not mimicked by 25-Hydroxycholesterol. 7-Ketocholesterol, but not 25-Hydroxycholesterol, can also decrease Akt and p-Akt levels. The effect of 7-Ketocholesterol can be partially reverted by the overexpression of a constitutively active Akt in SRA cells.
SRA cells undergo autophagy activation when exposed to 7-Ketocholesterol, possibly as a cell survival mechanism upon 7-Ketocholesterol induced stress. Chronic exposure may lead to autophagic cell death. 7-Ketocholestrol induced activation of Macroautophagy seems to be partially related to the PI3K-Akt-mTOR pathway.
This PDF is available to Subscribers Only