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SE Moroi, N McLaren; Beta Adrenergic Receptors in Human Ciliary Epithelium and Regulation by Dexamethasone . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4100.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To characterize the molecular diversity of beta-adrenergic receptors (AR) in human ciliary epithelium and their potential regulation by dexamethasone. Methods: A dissection method was established to isolate human ciliary epithelium from human donor eyes. Total RNA was isolated from human ciliary body, isolated ciliary epithelium, the human nonpigmented ciliary epithelial cell line ODM-2 (kindly donated by Dr. Miguel Coca-Prados, Yale Univ.), and appropriate control tissues. RT-PCR was performed on DNase-treated total RNA samples to characterize expression of the beta-ARs using sequence specific primers for the beta1-, beta2-, and beta3-ARs. The identity of RT-PCR products were confirmed by sequencing. Ribonuclease protection assay was also used to evaluate the beta2-AR transcript. Regulation of the beta2-AR transcript was evaluated by 100 nM dexamethasone treatment of ODM-2 cells grown in 10% stripped serum at various time points. The effect of dexamethosone on the beta2-AR transcript was evaluated using real time PCR with TaqMan and CyberGreen technologies. Results: Using RT-PCR, the beta1- and beta2-AR transcripts were identified and confirmed by sequencing in ODM-2, human ciliary epithelium, and human ciliary body. The beta3-AR transcript was found only in control cells, SKNMC. The beta2-AR transcript was also confirmed in ODM-2 using ribonuclease protection assay. Dexamethasone caused a time-dependent increase in beta2-AR transcript in ODM-2 detected by the TaqMan assay. Preliminary experiments using the CyberGreen real time PCR also detect an dexamethsone-induced up-regulation of the beta2-AR transcript. Conclusion: Our preliminary studies show that the beta2-AR transcript in human ciliary epithelium is up-regulated by dexamethasone. Additional studies are in progress to correlate these findings with beta2-AR expression by radioligand binding. This steroid-induced up-regulation of the beta2-ARs in ciliary epithelium may explain the effect of steroids on the previously described increase in aqueous humor flow by fluorophotometry.
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