Biochem. J. (2007) 402
(219–227) (Printed in Great Britain)
Elevated oxidative stress in erythrocytes due to a SOD1 deficiency causes anaemia and triggers autoantibody production
Yoshihito IUCHI*, Futoshi OKADA*, Kunishige ONUMA*, Tadashi ONODA†‡, Hironobu ASAO†, Masanobu KOBAYASHI§ and Junichi FUJII*1
*Department of Biomolecular Function, Graduate School of Medical Science, Yamagata University, Yamagata, Japan, †Department of Immunology, Yamagata University School of Medicine, Yamagata, Japan, ‡Department of Paediatrics, Yamagata University School of Medicine, Yamagata, Japan, and §Division of Cancer Pathobiology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
Reactive oxygen species are involved in the aging process and diseases. Despite the important role of Cu/Zn SOD (superoxide dismutase) encoded by SOD1, SOD1-/- mice appear to grow normally under conventional breeding conditions. In the present paper we report on a novel finding showing a distinct connection between oxidative stress in erythrocytes and the production of autoantibodies against erythrocytes in SOD1-/- mice. Evidence is presented to show that SOD1 is primarily required for maintaining erythrocyte lifespan by suppressing oxidative stress. A SOD1 deficiency led to an increased erythrocyte vulnerability by the oxidative modification of proteins and lipids, resulting in anaemia and compensatory activation of erythropoiesis. The continuous destruction of oxidized erythrocytes appears to induce the formation of autoantibodies against certain erythrocyte components, e.g. carbonic anhydrase II, and the immune complex is deposited in the glomeruli. The administration of an antioxidant, N-acetylcysteine, suppressed erythrocyte oxidation, ameliorated the anaemia, and inhibited the production of autoantibodies. These data imply that a high level of oxidative stress in erythrocytes increases the production of autoantibodies, possibly leading to an autoimmune response, and that the intake of antioxidants would prevent certain autoimmune responses by maintaining an appropriate redox balance in erythrocytes.
Key words: anaemia, autoantibody, carbonic anhydrase, oxidative stress, SOD1 deficiency.
Abbreviations used: ALS, amyotrophic lateral sclerosis; CAII, carbonic anhydrase II; CAT, catalase; DCFH-DA, 2´,7´-dichlorofluorescin diacetate; DHR123, dihydrorhodamine123; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GPX, glutathione peroxidase; GR, glutathione reductase; HRP, horseradish peroxidase; NAC, N-acetylcysteine; NHS-LC-biotin, N-succinimidyl-6-(biotinamide)hexanoate; Prx, peroxiredoxin; RBC, red blood cell; ROS, reactive oxygen species; SOD, superoxide dismutase; TBARS, thiobarbituric acid-reactive substances; TBS, Tris-buffered saline; TBST, Tris-buffered saline with Tween 20; TRX, thioredoxin.
1To whom correspondence should be addressed (email jfujii@med.id.yamagata-u.ac.jp).
Received 8 September 2006/23 October 2006; accepted 24 October 2006
Published as BJ Immediate Publication 24 October 2006, doi:10.1042/BJ20061386
The Biochemical Society, London ©2007
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