title: Melanosome-iron interactions within retinal pigment epithelium-derived cells.
abstract: Melanosomes were recently shown to protect ARPE-19 cells, a human retinal pigment epithelium (RPE) cell line, against oxidative stress induced by hydrogen peroxide. One postulated mechanism of antioxidant action of melanin is its ability to bind metal ions. The aim here was to determine whether melanosomes are competent to bind iron within living cells, exhibiting a property previously shown only in model systems. The outcomes indicate retention of prebound iron and accumulation of iron by granules after iron delivery to cells via the culture medium, as determined by both colorimetric and electron spin resonance analyses for bound-to-melanosome iron. Manipulation of iron content did not affect the pigment's ability to protect cells against H(2) O(2) , but the function of pigment granules within RPE cells should be extended beyond a role in light irradiation to include participation in iron homeostasis.
authors.affiliation: Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Kaczara
authors.forename: Mariusz
authors.initials: M
authors.lastname: Zaręba
authors.forename: Anja
authors.initials: A
authors.lastname: Herrnreiter
authors.forename: Christine M B
authors.initials: CM
authors.lastname: Skumatz
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ządło
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Sarna
authors.forename: Janice M
authors.initials: JM
authors.lastname: Burke
mesh_terms: D000818:Animals; D001052:Apoferritins / Q000378:metabolism; D002460:Cell Line; D003720:Densitometry; D004578:Electron Spin Resonance Spectroscopy; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism* / Q000494:pharmacology; D020460:Melanosomes / Q000187:drug effects / Q000378:metabolism*; D008858:Microscopy, Phase-Contrast; D018384:Oxidative Stress / Q000187:drug effects; D010587:Phagocytosis / Q000187:drug effects; D055213:Retinal Pigment Epithelium / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D034421:Sus scrofa
chemical_list: D001052:Apoferritins; D006861:Hydrogen Peroxide; D007501:Iron