Abstract
Purpose: :
Amyloid ß is supposed to be associated with pathogenesis of age-related macular degeneration because of the expression of amyloid ß in hard drusen. The aim of this study is to clarify the relationship of amyloid ß expression with physiological functions of retinal pigment epithelium (RPE).
Methods: :
Human RPE cells were cultured in medium with methylcellulose on 96-well round bottom culture dish. RPE cells aggregated and formed a spheroid, on the surface of which a monolayer of RPE was constructed. ß-secretase inhibitor or γ-secretase inhibitor was used to inhibit the production of amyloid ß from amyloid precursor protein (APP). At week 1, spheroids were measured in diameter and observed in morphology. Localization of apoB-100 and elastin was evaluated by immunohistochemistry.
Results: :
Diameters of spheroids in the group treated with each secretase inhibitor were bigger than those in the control group through the observation period. Outward deposition of lipoproteins in each treatment group was less than that in the control group. Spheroids in each treatment group had smooth surface. ApoB-100, a component of RPE-derived lipoproteins, and elastin, a major element of Bruch’s membrane, were stained in each group treated with secretase inhibitors less intensely than in the control group.
Conclusions: :
Amyloid ß inhibitor reduced the production of lipoproteins and the turnover of elastin. These results suggested that cleavage of APP by secretases might play a role in lipoprotein deposition, which might require subsequent reconstruction of Bruch’s membrane.
Keywords: age-related macular degeneration • retinal pigment epithelium • Bruch's membrane