Interferon regulatory factor-8-driven myeloid differentiation is regulated by 12/15-lipoxygenase-mediated redox signaling

Objective Several transcription factors determine the cell fate decision between granulocytes and monocytes, but the upstream signal transduction pathways that govern myelopoiesis are largely unknown Based on our observation of aberrant myeloid cell representation in hematopoietic tissues of 12/15 lipoxygenase (12/15 LOX) deficient (Alox15) mice, we tested the hypothesis that polyunsaturated fatty acid metabolism regulates myelopoiesis Materials and Methods Multicolor flow cytometric analysis and methylcellulose assays were used to compare myelopoiesis and the differentiative capacity of progenitors from Alox15 and wild type mice Furthermore, we elucidated the mechanism by which 12/15 LOX is Involved in regulation of myelopoiesis Results Granulopoiesis in Alox15 mice is Increased while monopoiesis is reduced Moreover, there is an accumulation of granulocyte-macrophage progenitors that exhibit defective differentiation Mechanistically, we demonstrate that transcriptional activity of interferon regulatory factor 8 (Irf8), which regulates myelopoiesis, is impaired in Alox15 progenitors and bone marrow derived macrophages due to loss of 12/15 LOX-mediated redox regulation of Irf8 nuclear accumulation Restoration of redox signaling in Alox15 bone marrow cells and granulocyte macrophage progenitors reversed the defect in myeloid differentiation Conclusions These data establish 12/15-LOX mediated redox signaling as a novel regulator of myelopiesis and Irf8 (C) 2010 ISEH Society for Hematology and Stem Cells Published by Elsevier Inc