Systemic deficiency of mouse arachidonate 15-lipoxygenase induces defective erythropoiesis and transgenic expression of the human enzyme rescues this phenotype

FASEB J. 2020 Nov;34(11):14318-14335. doi: 10.1096/fj.202000408RR. Epub 2020 Sep 12.

Abstract

Arachidonic acid 15-lipoxygenases (ALOX15) are lipid peroxidizing enzymes, which has previously been implicated in the maturational breakdown of intracellular organelles and plasma membrane remodeling during reticulocyte-erythrocyte transition. Conventional Alox15-/- mice are viable, develop normally but do not exhibit a major defective erythropoietic phenotype. To characterize the putative in vivo relevance of Alox15 for red blood cell development, we explored the impact of systemic inactivation of the Alox15 gene on mouse erythropoiesis. We found that Alox15-/- mice exhibited reduced erythrocyte counts, elevated reticulocyte counts and red cell hyperchromia. The structure of the plasma membrane of Alox15-/- erythrocytes is altered and a significant share of the red cells was present as echinocytes and/or acanthocytes. An increased share of the Alox15-/- erythrocytes cells were annexin V positive, which indicates a loss of plasma membrane asymmetry. Erythrocytes of Alox15-/- mice were more susceptible to osmotic hemolysis and exhibited a reduced ex vivo life span. When we transgenically expressed human ALOX15 in Alox15-/- mice under the control of the aP2 promoter the defective erythropoietic system was rescued and the impaired osmotic resistance was normalized. Together these data suggest the involvement Alox15 in the maturational remodeling of the plasma membrane during red cell development.

Keywords: biomembranes; differentiation; eicosanoids; lipid peroxidation; redox equilibrium; reticulocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arachidonate 12-Lipoxygenase / physiology*
  • Arachidonate 15-Lipoxygenase / administration & dosage*
  • Arachidonate 15-Lipoxygenase / physiology*
  • Erythropoiesis*
  • Hemolysis
  • Hyperpigmentation / etiology
  • Hyperpigmentation / prevention & control*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Phenotype
  • Reticulocytosis*
  • Transgenes*

Substances

  • Alox15 protein, mouse
  • Arachidonate 12-Lipoxygenase
  • ALOX15 protein, human
  • Arachidonate 15-Lipoxygenase