Title of article :
Memantine, Simvastatin, and Epicatechin Inhibit 7-Ketocholesterol-induced Apoptosis in Retinal Pigment Epithelial Cells But Not Neurosensory Retinal Cells In Vitro
Author/Authors :
Neekhra, Aneesh Gavin Herbert Eye Institute - University of California - Irvine - California , Tran, Julia Gavin Herbert Eye Institute - University of California - Irvine - California , Esfahani, Parsa R. Gavin Herbert Eye Institute - University of California - Irvine - California , Schneider, Kevin Gavin Herbert Eye Institute - University of California - Irvine - California , Pham, Khoa Gavin Herbert Eye Institute - University of California - Irvine - California , Sharma, Ashish Gavin Herbert Eye Institute - University of California - Irvine - California , Chwa, Marilyn Gavin Herbert Eye Institute - University of California - Irvine - California , Luthra, Saurabh Gavin Herbert Eye Institute - University of California - Irvine - California , Gramajo, Ana L. Gavin Herbert Eye Institute - University of California - Irvine - California , Mansoor, Saffar Gavin Herbert Eye Institute - University of California - Irvine - California , Kuppermann, Baruch D. Gavin Herbert Eye Institute - University of California - Irvine - California , Kenney, M. Cristina Gavin Herbert Eye Institute - University of California - Irvine - California - Department of Pathology and Laboratory Medicine - University of California Irvine - Irvine - CA - USA
Abstract :
Purpose: 7-ketocholesterol (7kCh), a natural byproduct of oxidation in lipoprotein deposits is implicated in the pathogenesis of diabetic retinopathy and age-related macular degeneration (AMD). This study was performed to investigate whether several
clinical drugs can inhibit 7kCh-induced caspase activation and mitigate its apoptotic
effects on retinal cells in vitro.
Method: Two populations of retinal cells, human retinal pigment epithelial cells (ARPE-19)
and rat neuroretinal cells (R28) were exposed to 7kCh in the presence of the following
inhibitors: Z-VAD-FMK (pan-caspase inhibitor), simvastatin, memantine, epicatechin, and
Z-IETD-FMK (caspase-8 inhibitor) or Z-ATAD-FMK (caspase-12 inhibitor). Caspase-3/7, -8,
and -12 activity levels were measured by fluorochrome caspase assays to quantify cell
death. IncuCyte live-cell microscopic images were obtained to quantify cell counts.
Results: Exposure to 7kCh for 24 hours significantly increased caspase activities for
both ARPE-19 and R28 cells (P < 0.05). In ARPE cells, pretreatment with various drugs
had significantly lower caspase-3/7, -8, and -12 activities, reported in % change in mean
signal intensity (msi): Z-VAD-FMK (48% decrease, P < 0.01), memantine (decreased 47.8%
at 1 μM, P = 0.0039 and 81.9% at 1 mM, P < 0.001), simvastatin (decreased 85.3% at 0.01
μM, P < 0.001 and 84.8% at 0.05 μM , P < 0.001) or epicatechin (83.6% decrease, P
< 0.05), Z-IETD-FMK (68.1% decrease, P < 0.01), and Z-ATAD-FMK (47.7% decrease, P =
0.0017). In contrast, R28 cells exposed to 7kCh continued to have elevated caspase-
3/7, -8, and -12 activities (between 25.7% decrease and 17.5% increase in msi, P > 0.05)
regardless of the pretreatment.
Conclusion: Several current drugs protect ARPE-19 cells but not R28 cells from 7kChinduced apoptosis, suggesting that a multiple-drug approach is needed to protect both cells types in various retinal diseases.
Keywords :
Epicatechin , 7-Ketocholesterol , Memantine
Journal title :
Journal of Ophthalmic and Vision Research
