Abstract
Purpose :
The retinal pigment epithelium (RPE) is constantly damaged by oxidative stress, particularly due to reactive oxygen species (ROS). Recently, it has been observed that excessive ROS formation in RPE cells can deregulate other physiological mechanisms, such apoptosis or autophagy. Autophagy and apoptosis activity in RPE cells increase after ROS damage induced by EtOH. Enhanced ROS increase the number of multivesicular bodies (MVBs), which eventually will either join the lysosome being degraded or fuse with cell membrane releasing exosomes. Hence, ROS overproduction increases at once autophagy, apoptosis activity, and exosome liberation. Our purpose is to observe if exosomes released after damage contain a different cargo from those released from control RPE cells. Moreover, we want to elucidate whether those exosomes might potentially damage neighboring healthy cells.
Methods :
Exosomes derived from ARPE-19 control and treatment with EtOH (24h) were isolated by ultracentrifugation and quantified by means of flow cytometry. The protein profile and content of Bax, Bcl-2, and CD9 were assayed by Flow citometry and western blot. mRNA was assayed by qPCR. Control ARPE-19 cells were treated with exosomes from control and treated cells, and the effect in cell cycle was observed.
Results :
EtOH exposure induced exosome biogenesis and changes in their cargo. Stressed cells presented an enhanced fraction of Bax-positive exosomes. Moreover, when healthy ARPE-19 were treated with these stressed-exosomes, cell death was significantly augmented.
Conclusions :
Oxidative stress produced by ethanol seems to affect exosome production in numbers and cargo in ARPE-19 cells. These released stressed-exosomes influence neighboring cells by delivering their cargo into them and thus producing cell death.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.