The Regulation of Erythropoiesis by Selenium in Mice

Redox modulation by antioxidants, such as selenium (Se), has emerged as an important regulator of erythropoiesis. Using Se-deficient (0.04 ppm), Se-adequate (0.1 ppm), and Se-supplemented (0.4 ppm) C57/BL6 mice, we show that Se deficiency caused anemia, when compared to the Se-supplemented and Se-adequate groups. Increased denaturation of hemoglobin, methemoglobin, protein carbonyls, lipid peroxidation, Heinz bodies, and osmotic fragility of erythrocytes were observed in Se-deficient mice. Increased oxidative stress upregulated forkhead transcription factor (FoxO3a) and hypoxia-inducible factor-(HIF)1 alpha in the spleen and kidney of Sedeficient murine as well as in the proerythroblast G1E cells cultured in Se-deficient media. A significant increase in the expression of erythropoietin, a downstream target of HIF1 alpha, and expansion of stress erythroid progenitors (burst forming units-erythroid) were seen in the Se-deficient mice. Despite the increase in erythroid progenitors, lowered reticulocytes suggest a defective erythroid differentiation pathway. While Se deficiency led to increased nuclear levels of active FoxO3a, Se-adequate conditions reversed this effect and increased nuclear export by its binding partner, 14-3-3 beta zeta, that is under the redox control of selenoproteins. In summary, these results provide insight into the importance of adequate Se nutrition in regulating red cell homeostasis by mitigating oxidative stress-dependent modulation of FoxO3a and HIF1 alpha to effect differentiation of erythroid progenitors. Antioxid. Redox Signal. 14, 1403-1412.