Induction of heme oxygenase-1 modulates cis-aconitase activity in lens epithelial cells.
Heme oxygenase-1 is the heme catabolic enzyme induced in human dermal fibroblasts by environmental stress. We report an increase of heme oxygenase-1 message in lens epithelial cells after exposure to UVA radiation, followed by a 10-fold increase of protein expression. The size of message was larger than previously demonstrated for fibroblasts. The relationship between heme oxygenase-1 activation and iron metabolism was investigated by measurement of activities of both cytosolic and mitochondrial cis-aconitase enzymes. A 2-fold increase in mitochondrial cis-aconitase activity in UVA-exposed cells coincided with the time of maximal heme oxygenase-1 expression. We propose that modulation of cis-aconitase activity at the translational level by an increase of cellular iron is an important consequence of heme oxygenase-1 activation. This might be a novel aspect of the protective role of heme oxygenase-1 in modulating the response of cells challenged with oxidative stress.
Rzymkiewicz
D M
DM
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Reddan
J R
JR
Andley
U P
UP
D000154:Aconitate Hydratase / Q000378:metabolism*; D000818:Animals; D003600:Cytosol / Q000201:enzymology; D004790:Enzyme Induction; D004847:Epithelial Cells / Q000201:enzymology / Q000528:radiation effects; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D051547:Heme Oxygenase-1; D007908:Lens, Crystalline / Q000201:enzymology* / Q000528:radiation effects*; D008928:Mitochondria / Q000201:enzymology; D011817:Rabbits; D014466:Ultraviolet Rays
D006360:Heat-Shock Proteins; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D000154:Aconitate Hydratase