title: Targeted disruption of Nrf2 causes regenerative immune-mediated hemolytic anemia.
abstract: A basic leucine zipper transcription factor, NF-E2-related factor 2 (Nrf2), plays a critical role in the cellular defense mechanism by mediating a coordinate up-regulation of antioxidant responsive element-driven detoxification and antioxidant genes. Here, we report that targeted disruption of Nrf2 causes regenerative immune-mediated hemolytic anemia due to increased sequestration of damaged erythrocytes. Splenomegaly and spleen toxicity in Nrf2(-/-) mice raised a possibility of hemolytic anemia and splenic extramedullary hematopoiesis in Nrf2(-/-) mice. In support of this, hematology analysis revealed that Nrf2(-/-) mice suffer from anemia with abnormal red cell morphologies (i.e., Howell-Jolly bodies, acantocytes, and schistocytes). In addition, Nrf2(-/-) erythrocytes were more sensitive to H(2)O(2)-induced hemolysis, and erythrocyte-bound IgG levels were markedly increased in Nrf2(-/-) mice compared with Nrf2(+/+) mice. Because IgG bound to erythrocytes in the presence of oxidative damage in erythrocytes (regardless of Nrf2 genotype), these data support that Nrf2(-/-) erythrocytes have higher levels of damage compared with Nrf2(+/+) cells. Finally, Nrf2(-/-) mice showed increased levels of erythrocyte-bound IgG compared with Nrf2(+/+) mice after H(2)O(2) injection in vivo, suggesting that the decreased glutathione and increased H(2)O(2) render the Nrf2(-/-) mice more susceptible to toxicity. Taken together, these observations indicate that a chronic increase in oxidative stress due to decreased antioxidant capacity sensitizes erythrocytes and causes hemolytic anemia in Nrf2(-/-) mice, suggesting a pivotal role of Nrf2-antioxidant responsive element pathway in the cellular antioxidant defense system.
authors.affiliation: School of Pharmacy, Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53705, USA.
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Kaimin
authors.initials: K
authors.lastname: Chan
authors.forename: Yuet Wai
authors.initials: YW
authors.lastname: Kan
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Johnson
mesh_terms: D000744:Anemia, Hemolytic, Autoimmune / Q000235:genetics* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D017353:Gene Deletion; D005786:Gene Expression Regulation; D005838:Genotype; D006461:Hemolysis / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D051267:NF-E2-Related Factor 2; D018384:Oxidative Stress / Q000187:drug effects; D010641:Phenotype; D020218:Response Elements / Q000235:genetics; D013154:Spleen / Q000378:metabolism / Q000473:pathology; D013163:Splenomegaly / Q000235:genetics / Q000473:pathology; D014070:Tooth / Q000502:physiology; D015534:Trans-Activators / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004268:DNA-Binding Proteins; D007074:Immunoglobulin G; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D015534:Trans-Activators; D006861:Hydrogen Peroxide