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Xinyu Fu, Ru Lin, Yiguo Qiu, Peng Yu, Bo Lei; Overexpression of Angiotensin-Converting Enzyme 2 Ameliorates Amyloid β-Induced Inflammatory Response in Human Primary Retinal Pigment Epithelium. Invest. Ophthalmol. Vis. Sci. 2017;58(7):3018-3028. doi: 10.1167/iovs.17-21546.
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© ARVO (1962-2015); The Authors (2016-present)
Amyloid-β (Aβ) is a major constituent of drusen, which is a hallmark of early AMD. The purpose of this study was to investigate whether enhancement of ACE2, an important component of the protective angiotensin-converting enzyme 2 (ACE2)/Ang-(1-7)/Mas axis of the renin angiotensin system (RAS), ameliorates Aβ-induced inflammatory response in human RPE cells.
Annexin-V FITC/propidium iodide assay for detecting apoptosis rate was used to determine the optimum concentration and incubation time of Aβ1-42. ACE2 plasmid was transfected into primary cultured human RPE (hRPE) and ARPE-19 cells for 6 hours followed by stimulation with Aβ1-42 at the concentration of 1 μM for 48 hours. Gene expression was detected by real-time PCR and protein levels were determined by Western blotting or ELISA. A779, an antagonist of Ang-(1-7), was used to further confirm the involvement of ACE2/Ang-(1-7)/Mas axis.
Flow cytometry showed that the optimal concentration of Aβ1-42 was 1 μM and the optimal incubation time was 48 hours. Aβ1-42 upregulated the expression of IL-1β and monocyte chemoattractant protein-1. ACE2 plasmid significantly upregulated the expression of ACE2 and Ang-(1-7) in hRPE and ARPE-19 cells. Activation of ACE2 reduced the overproduction of inflammatory cytokines at both mRNA and protein levels in hRPE and ARPE-19 cells stimulated with Aβ1-42. Furthermore, an antagonist of Ang-(1-7), A779 reversed the anti-inflammatory effect of ACE2.
Overexpression of ACE2 ameliorates Aβ-induced inflammatory response by activating the ACE2/Ang-(1-7)/Mas axis in human RPE cells. Our data suggest that ACE2/Ang-(1-7)/Mas axis may be a promising target for developing novel therapies for inflammation response in AMD.
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