Purchase this article with an account.
David M. Rabin, Ali Reza Ladiwala, Timothy A. Blenkinsop, Richard L. Rabin, Peter M. Tessier, Sheldon Miller, Sally Temple, Jeffrey H. Stern; Amyloid-β42 Oligomers Induce Drusen-related Protein Expression and Cytotoxicity in Human RPE Cells: A Mechanism for Drusen Formation and Progression of Age-Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5296.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Amyloid-β (Aβ) has been identified specifically in drusen of patients with Age-Related Macular Degeneration (AMD) and has been implicated in AMD pathogenesis. Apart from an important role in activating the complement system, other possible mechanisms of action remain unclear. We examined the response of human retinal pigment epithelium (RPE) to chronic Aβ exposure in a ‘disease-in-a-dish’ culture model to test the hypothesis that Aβ might stimulate drusen formation and thereby promote AMD progression. Additionally, we investigated how the interaction between Aβ and a major drusen protein, αB-crystallin, affects the RPE.
Fetal or adult (AMD versus non-AMD) human RPE cells from donated eyes were cultured with placental extracellular matrix for 4 weeks until a highly pure, confluent polarized monolayer developed. RPE were exposed to Aβ42 monomers, non-toxic oligomers, toxic oligomers, and fibrils (1-5μM), the Aβ (42-1) reverse peptide control, or vehicle control for 24-120 hours. Following Aβ exposure, cells and media were collected for drusen-related protein, mRNA, and cytotoxicity analysis.
A significant up-regulation in drusen-related proteins occurred in a dose- and time-dependent manner with exposure to toxic oligomers of Aβ42 (AβTO). Other Aβ42 forms had no significant effect on cell death or drusen-related protein expression. Notably, RPE cells exposed to 120 hours of AβTO demonstrated a significant up-regulation in αB-crystallin and VEGF. Proteins found to be up-regulated in this model are up-regulated in RPE of human AMD eyes and serve as molecular markers for AMD.
The results from this RPE chronic stress model suggest that AβTO alone are capable of inducing human RPE to up-regulate synthesis of drusen-related proteins and cause cell death. The induction of αB-crystallin is of particular importance, as it has been observed to stabilize the AβTO with pro-angiogenic and neurotoxic effects. The results of this study implicate AβTO accumulation as a major player in the advancement of dry AMD and potentially neovascular transformation, and suggest new targets for the development of therapeutics for dry AMD.
This PDF is available to Subscribers Only