Protective effect of clusterin from oxidative stress-induced apoptosis in human retinal pigment epithelial cells.
OBJECTIVE
Oxidative stress to retinal pigment epithelial (RPE) cells is thought to play a critical role in the pathogenesis of age-related macular degeneration (AMD). This study was conducted to investigate whether clusterin protects human RPE cells from ROS-induced apoptosis through a PI3K/Akt survival pathway.


METHODS
The preventive effect of clusterin on reactive oxygen species (ROS) production and RPE cell death induced by hydrogen peroxide was determined in ARPE-19 cells. The ability of clusterin to protect RPE cells against ROS-mediated apoptosis was assessed by caspase-3 activity and DAPI staining. Furthermore, the protective effect of clusterin via the PI3K/Akt pathway was determined by Western blot analysis.


RESULTS
Clusterin prevented ARPE-19 cells from H(2)O(2)-induced cell death and ROS production. H(2)O(2)-induced oxidative stress increased caspase-3 activity, which was significantly inhibited by clusterin, as determined by the abrogation of apoptotic bodies. Interestingly, clusterin induced Akt phosphorylation in human RPE cells under oxidative stress, which contributed to cell viability in ARPE-19 cells. This cell survival by clusterin was blocked by a PI3K inhibitor.


CONCLUSIONS
Clusterin may play a protective role in responding to the local redox environment of human RPE cells, which contributes to the cell survival via the PI3K/Akt pathway. Therefore, clusterin could be considered for the preventive approach to AMD.
Kim
Jeong Hun
JH
Fight against Angiogenesis-Related Blindness Laboratory, Department of Ophthalmology, Seoul National University College of Medicine and Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea.
Kim
Jin Hyoung
JH
Jun
Hyoung Oh
HO
Yu
Young Suk
YS
Min
Bon Hong
BH
Park
Kyu Hyung
KH
Kim
Kyu-Won
KW
D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival; D051152:Clusterin / Q000502:physiology*; D019610:Cytoprotection; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D018384:Oxidative Stress; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C495242:CLU protein, human; D051152:Clusterin; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D053148:Caspase 3