Origin, Function, and Fate of Metallothionein in Human Blood
Toxic heavy metals, toxic organic compounds, reactive oxygen species (ROS), infections, and temperature are well-known metallothionein (MT) inducers in human blood. The current review aims to summarize synthesis, function, and fate of human blood MT in response to the known MT inducers. Part of the MTs that are synthesized in different organs such as the liver, kidney, and spleen is transported and stored in different blood cells and in plasma. Cells of the circulatory system also synthesize MT. From the circulation, MT returns to the kidney where the metal-bound MTs are degraded to release the metal ion that in turn induces MT expression therein. The blood MTs play important roles in metal detoxification, transportation, and storage. By neutralizing ROS, MTs protect blood cells from oxidative stress-induced cytotoxicity and genotoxicity. Arguably, MTs are also involved in immune suppression. Given the permeating distribution of blood MT throughout the body as well as its diverse role in the protection against harmful environmental factors and in metal homeostasis, MT could be better recognized as a major public health protein.
KeywordsArsenic Cadmium Cytotoxicity Metal response elements Reactive oxygen species Renal toxicity Zinc
This work was supported by High Impact Research MOHE Grant UM.C/625/1/HIR/MOHE/DENT/01 and from the Ministry of Higher Education Malaysia and the Fonds voor Wetenschappelijk Onderzoek-Vlaanderen (G.0410.98), Belgium.
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