• OGFOD1
• Haematopoiesis
• Leukaemia
• MLL
• AML

The haematopoietic system critically depends on rare multipotent haematopoietic stem cells (HSCs) that sustain life-long multilineage haematopoiesis. HSCs are mostly quiescent, undergo self-renewal, and generate primitive progenitor cells that give rise to all blood lineages. A number of studies have demonstrated that the strict regulation of these fate decisions is essential for normal haematopoiesis. HSCs reside in niches within the bone marrow (BM) where they are subject to very low oxygen concentrations (hypoxia). HSCs can sense oxygen concentration and respond to hypoxia with adaptive changes in gene expression relating to angiogenesis and glycolysis. OGFOD1 is a protein that belongs to the group of Iron [Fe(II)]- and 2-oxoglutarate (2OG)-dependent oxygenases that is important for cellular adaptation to changes in oxygen concentrations. These highly conserved 2OG oxygenases have diverse biochemical and biological functions, however in animals, their biochemical activities are limited to hydroxylations or demethylations via hydroxylation.
Thus, this project aims to investigate the role of this relatively new protein in normal adult haematopoiesis. We therefore, analysed the haematopoietic compartment of young (8-12 week old) and old sex- and age-matched (1.5 year old) OGFOD1+/+, OGFOD1+/- and OGFOD1-/- mice. We found that mice lacking OGFOD1 displayed an expansion of primitive (lineage negative) cells and an increase in myeloid cells. Next, we tested the self-renewal capacity of HSCs lacking OGFOD1 by transplanting total BM from OGFOD1+/+, OGFOD1+/- and OGFOD1-/- mice alongside wild type (WT) BM into irradiated recipients in a competitive assay. We are currently monitoring these mice by serial analyses of their blood compartments.

Next, given that these mice display an expansion of primitive and myeloid cells which are hallmarks of Acute Myeloid Leukaemia (AML), we aim to investigate whether OGFOD1 has a role in the initiation and maintenance of AML.
In acute myeloid leukaemia (AML), the acquisition of initiating mutations by HSCs and progenitors dysregulates stem cell fate decisions and generates pre-leukaemic stem cells (pre-LSCs). Under permissive conditions, pre-LSCs acquire cooperating mutations and generate leukaemic stem cells (LSCs) that drive leukaemogenesis and are difficult to eradicate using currently available treatments. We have therefore employed a retroviral in vitro model of AML whereby co-expression of oncoproteins Meis1 and HoxA9 in stem and progenitor cells results in the generation of Pre-LSCs that serially re plate in semi-solid medium. This assay will help us determine whether OGFOD1 alters the proliferative and self-renewal properties of pre-LSCs. Finally, we have transplanted these pre-LSCs into lethally irradiated recipients alongside WT BM to determine whether OGFOD1 plays a role in the initiation of AML in vivo. Collectively, these important studies will allow us to decipher the already exciting role of OGFOD1 in haematopoiesis.