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Title: Microphthalmia-associated transcription factor as the molecular target of cadmium toxicity in human melanocytes

Highlights: • In human melanocytes, cadmium decreases the expression of MITF-M and tyrosinase and their mRNAs. • In human melanoma cells, cadmium decreases the expression of MITF-M protein and tyrosinase mRNA. • Expression of MITF-H is less sensitive to cadmium toxicity in melanocyte-linage cells. • Cadmium does not decrease the expression of MITF-H in retinal pigment epithelial cells. • MITF-M is the molecular target of cadmium toxicity in melanocytes. - Abstract: Dietary intake of cadmium is inevitable, causing age-related increase in cadmium accumulation in many organs, including hair, choroid and retinal pigment epithelium (RPE). Cadmium has been implicated in the pathogenesis of hearing loss and macular degeneration. The functions of cochlea and retina are maintained by melanocytes and RPE, respectively, and the differentiation of these pigment cells is regulated by microphthalmia-associated transcription factor (MITF). In the present study, we explored the potential toxicity of cadmium in the cochlea and retina by using cultured human melanocytes and human RPE cell lines. MITF consists of multiple isoforms, including melanocyte-specific MITF-M and widely expressed MITF-H. Levels of MITF-M protein and its mRNA in human epidermal melanocytes and HMV-II melanoma cells were decreased significantly by cadmium. In parallel with the MITF reduction, mRNA levelsmore » of tyrosinase, the key enzyme of melanin biosynthesis that is regulated by MITF-M, were also decreased. In RPE cells, however, the levels of total MITF protein, constituting mainly MITF-H, were not decreased by cadmium. We thus identify MITF-M as the molecular target of cadmium toxicity in melanocytes, thereby accounting for the increased risk of disability from melanocyte malfunction, such as hearing and vision loss among people with elevated cadmium exposure.« less
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [3] ;  [1]
  1. Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai (Japan)
  2. (Thailand)
  3. Department of Zoology, Faculty of Science, Kasetsart University, Bangkok (Thailand)
Publication Date:
OSTI Identifier:
22416849
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 454; Journal Issue: 4; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ANIMAL CELLS; BIOSYNTHESIS; CADMIUM; EPITHELIUM; HAIR; HEME; HUMAN POPULATIONS; MELANIN; MELANOMAS; MESSENGER-RNA; PATHOGENESIS; RETINA; RHODOPSIN; TOXICITY; TRANSCRIPTION FACTORS; TYROSINASE; UVEA