Indoleamine 2,3-dioxygenase Protects Corneal Endothelial Cells from Uv Mediated Damage.
From: Department of Ophthalmology, SMZ-Ost, Donauspital, Langobardenstrasse 122, 1220 Wien, Vienna, Austria. nermin.serbecic@web.de
Experimental eye research
- Publish Date: Mar 2006
- ISSN: 0014-4835
- Volume: 82
- Issue: 3
- Pages: 416-26
- Medium: Print
- Language: English
- Citation (JAMA): Serbecic Nermin, Beutelspacher Sven Christoph, et al. Indoleamine 2,3-dioxygenase Protects Corneal Endothelial Cells from Uv Mediated Damage.. Exp. Eye Res. Mar 2006;82:416-26
Abstract
Indoleamine-2,3-dioxygenase (IDO) is an intracellular enzyme present in dendritic cells and macrophages. It is a known modulator of T-cell response and contributes to the UV protection of the lens. There yet is no information on IDO activity in the corneal endothelium, protecting the endothelial cells from light mediated damage. We exposed murine corneal endothelial cells (MCEC) with different doses of UV-B light 280-320 nm, probed for IDO mRNA (real-time PCR) and assessed apoptosis rate (flow cytometry) and caspase-3-activity in the cells. The metabolites of the IDO catalysed reaction, l-kynurenine, was also measured. Malondialdehyde was detected for quantification of UV-B-induced oxidative stress. To investigate specificity, IDO effects were blocked by 1-methyl-tryptophan. The effects of IDO overexpression in the MCEC were assessed by transfection of an expression vector. MCEC consistently express IDO at low levels. Exposure to UV-B light led to a dose-responding upregulation of IDO; IDO was found competent converting l-tryptophan into l-kynurenine. Irradiation led to increased apoptosis and caspase-3-activity of MCEC. Supplementation of l-kynurenine or overexpression of IDO in the MCEC could reduce apoptosis significantly following UV-B irradiation. Inhibition of IDO by 1-MT was potent to reverse this effect. IDO and its metabolite l-kynurenine can protect corneal endothelial cells from UV-B-induced oxidative stress and apoptosis. It may be an active protection mechanism against corneal endothelial damage.
Mesh Headings (Keywords): Animals, Annexin A5, Caspase 3, Caspases, Cells, Cultured, Endothelium, Corneal, Flow Cytometry, Indoleamine-Pyrrole 2,3,-Dioxygenase, Mice, Mice, Inbred C57BL, Microscopy, Confocal, Reverse Transcriptase Polymerase Chain Reaction, Thiobarbituric Acid Reactive Substances, Transfection, Ultraviolet Rays
Check for Full Text / PubMed Unique Identifier (PMID): 16318852
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