Purchase this article with an account.
Hyae Jung Hyun, Joon Hong Sohn, Dong Wook Ha, Young Ho Ahn, Jae-Young Koh, Young Hee Yoon; Depletion of Intracellular Zinc and Copper with TPEN Results in Apoptosis of Cultured Human Retinal Pigment Epithelial Cells. Invest. Ophthalmol. Vis. Sci. 2001;42(2):460-465.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
purpose. Although zinc deficiency may contribute to the pathogenesis of age-related
macular degeneration, how it leads to retinal pigment epithelium (RPE)
degeneration is unknown. To investigate this, cultured human RPE cells
were rendered zinc depleted with a membrane-permeant metal chelator, N,N,N′,N-tetrakis(2-pyridylmethyl) ethylenediamine
(TPEN), and the resultant cytopathic changes were examined.
methods. RPE cell degeneration was examined with light microscopy, TdT-mediated
dUTP nick end labeling (TUNEL) staining, Hoechst dye staining, and
electron microscopy and quantified with cell counting or lactate
dehydrogenase release assay. The effect of sublethal zinc depletion on
the vulnerability of RPE cells to UV irradiation or hydrogen peroxide
(H2O2) exposure, was studied in cultures
without or with pretreatment with low-concentration TPEN.
results. Exposure to 1 to 4 μM TPEN for 48 hours induced RPE cell death in a
concentration-dependent manner. Features of apoptosis such as membrane
blebbing, chromatin condensation, nuclear fragmentation, and caspase-3
activation, accompanied the TPEN-induced cell death. Addition of
equimolar zinc or copper completely reversed TPEN-induced apoptosis,
whereas addition of iron had no effect. As in apoptosis of several
other cell types including neurons, a protein synthesis inhibitor as
well as caspase inhibitors blocked TPEN-induced apoptosis. On the
contrary, at sublethal concentrations, TPEN increased the vulnerability
of RPE cells to subsequent UV irradiation but not to
conclusions. The present results suggest that depletion of intracellular zinc and
copper, but not copper alone, may be harmful to RPE cells, directly
inducing apoptosis or indirectly increasing vulnerability of RPE
cells to UV injury. The present culture model may be useful for gaining
insights into the mechanisms of zinc depletion-associated RPE
This PDF is available to Subscribers Only