Abstract
AbstractArachidonic acid 15-lipoxygenases (ALOX15) play a role in mammalian erythropoiesis but they have also been implicated in inflammatory processes. Seven intact Alox genes have been detected in the mouse reference genome and the mouse Alox15 gene is structurally similar to the orthologous genes of other mammals. However, mouse and human ALOX15 orthologs have different functional characteristics. Human ALOX15 converts C20 polyenoic fatty acids like arachidonic acid mainly to the n-6 hydroperoxide. In contrast, the n-9 hydroperoxide is the major oxygenation product formed by mouse Alox15. Previous experiments indicated that Leu353Phe exchange in recombinant mouse Alox15 humanized the catalytic properties of the enzyme. To investigate whether this functional humanization might also work in vivo and to characterize the functional consequences of mouse Alox15 humanization we generated Alox15 knock-in mice (Alox15-KI), in which the Alox15 gene was modified in such a way that the animals express the arachidonic acid 15-lipoxygenating Leu353Phe mutant instead of the arachidonic acid 12-lipoxygenating wildtype enzyme. These mice develop normally, they are fully fertile but display modified plasma oxylipidomes. In young individuals, the basic hematological parameters were not different when Alox15-KI mice and outbred wildtype controls were compared. However, when growing older male Alox15-KI mice develop signs of dysfunctional erythropoiesis such as reduced hematocrit, lower erythrocyte counts and attenuated hemoglobin concentration. These differences were paralleled by an improved ex vivo osmotic resistance of the peripheral red blood cells. Interestingly, such differences were not observed in female individuals suggesting gender specific effects. In summary, these data indicated that functional humanization of mouse Alox15 induces defective erythropoiesis in aged male individuals.
Graphical Abstract
Funder
Deutsche Forschungsgemeinschaft
Publisher
Springer Science and Business Media LLC
Subject
Cell Biology,Molecular Biology,Biochemistry
Reference56 articles.
1. Lubrano V, Gabriele M, Puntoni MR, Longo V, Pucci L. Relationship among Il-6, Ldl cholesterol and lipid peroxidation. Cell Mol Biol Lett. 2015;20(2):310–22. https://doi.org/10.1515/cmble-2015-0020.
2. Liu P, Feng Y, Li H, Chen X, Wang G, Xu S, et al. Ferrostatin-1 alleviates lipopolysaccharide-induced acute lung injury via inhibiting ferroptosis. Cell Mol Biol Lett. 2020;25:10. https://doi.org/10.1186/s11658-020-00205-0. (Epub 2020/03/13).
3. Ivanov I, Heydeck D, Hofheinz K, Roffeis J, O’Donnell VB, Kuhn H, et al. Molecular enzymology of lipoxygenases. Arch Biochem Biophys. 2010;503(2):161–74. https://doi.org/10.1016/j.abb.2010.08.016.
4. Skorzynska-Polit E, Krupa Z. The activity of lipoxygenase in Arabidopsis thaliana (L.) Heynh – a preliminary study. Cell Mol Biol Lett. 2003;8(2):279–84 (Epub 2003/06/19).
5. Singh NK, Rao GN. Emerging role of 12/15-lipoxygenase (ALOX15) in human pathologies. Prog Lipid Res. 2019;73:28–45. https://doi.org/10.1016/j.plipres.2018.11.001. (Epub 2018/11/26).