Purchase this article with an account.
M.E. Marin Castaño, K.G. Csaky, S.W. Cousins; Angiotensin II Receptor Subtypes Expression in Human Retinal Pigment Epithelium . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2282.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: ARMD pathogenesis is clearly multifactorial involving genetic, systemic health and environmental risk factors. Hypertension (HTN) is a systemic health factor associated with ARMD severity. We postulate that HTN might contribute to RPE injury and subretinal deposit formation in ARMD through the actions of HTN-associated hormones like angiotensin II (Ang-II). Ang-II can induce superoxide formation and/or dysregulated turnover of the extracellular matrix (ECM). The actions of Ang-II are mediated by two seven-transmembrane domain G-protein coupled receptors, named the AT1 receptor and AT2 receptor. Our aims were to identify the presence of these angiotensin receptors in human RPE and to study their activity.Methods: Expression of Ang-II receptors was examined in freshly isolated human RPE and in cultured human RPE-19 cells, by using total RNA for RT-PCR and protein extracts for western blot analysis. The activity of the expressed receptors was assessed by measurement of intracellular calcium ([Ca2+]i) concentration. MMP-2 activity was determined by zymography. Results: Human RPE expressed both Ang II receptor subtypes AT1 and AT2 at the mRNA and protein levels. Stimulation of cultured RPE with Ang II at physiologic concentrations in the presence of Fura 2-AM induced ([Ca2+]i) mobilization. Ang-II also increased MMP-2 activity. Conclusions: This study demonstrates the presence of functional Ang-II receptors in human RPE. The presence of these Ang-II receptors confirms the potential for RPE as a target for angiotensin-modified responses.
This PDF is available to Subscribers Only