Ergothioneine is a thiourea derivative of histidine found in food, especially mushrooms. Experiments in cell-free systems and chemical assays identified this compound as a powerful antioxidant. Experiments were designed to test the ability of endothelial cells to take up ergothioneine and hence benefit from protection against oxidative stress. RT-PCR and Western blotting demonstrated transcription and translation of an ergothioneine transporter in human brain microvascular endothelial cells (HBMECs). Uptake of [3H]ergothioneine occurred by the organic cation transporter novel type-1 (OCTN-1), was sodium-dependent and was reduced when expression of OCTN-1 was silenced by siRNA. The effect of ergothioneine on the production of reactive oxygen species (ROS) in HBMECs was measured using dichlorodihydrofluorescin and lucigenin, and the effect on cell viability was studied using the 3-(4,5-Dimethylthgiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. ROS production and cell death induced by pyrogallol, xanthine oxidase plus xanthine and high glucose were suppressed by ergothioneine. The antioxidant and cytoprotective effects of ergothionine were abolished when OCTN-1 was silenced using siRNA. The expression of NADPH oxidase 1 was decreased, and those of glutathione reductase, catalase and superoxide dismutase enhanced by the compound. Ergothioneine attenuated the reduction in relaxation of isolated rat basilar arteries to the endothelium-dependent vasodilator acetylcholine caused by pyrogallol, xanthine oxidase plus xanthine or incubation in high glucose. Chronic treatment with the compound improved the response to acetylcholine in arteries of rats with streptozotocin-induced diabetes. In summary, ergothioneine is taken up by endothelial cells via OCTN-1, where the compound then protects against oxidative stress, curtailing endothelial dysfunction.
- cardiovascular disease
- organic cation transport
- oxidative stress
- reactive oxygen species (ROS)
- The American Society for Pharmacology and Experimental Therapeutics