P&F Projects 2023-2024
Mancuso Abstract Type A P&F 2024
Although metabolism is required to sustain the basic needs of all cells, specific metabolic changes also strongly influence stem cell fate and function. Hematopoietic stem cells (HSCs) maintain a low mitochondrial metabolic activity and rely on anaerobic glycolysis to support ATP production during quiescence and depend on oxidative phosphorylation (OXPHOS) for activation and differentiation. Although much has been determined regarding the metabolism of HSC, little is known regarding the relevance of the metabolism in megakaryocyte-erythroid progenitors (MEP) specification. My preliminary data reveal significant metabolic differences between MEP and their downstream lineage committed progenitors. With the goal of elucidating how metabolism regulates/affects MEP fate, I propose to use LC-MS to determine specific metabolic shifts as primary human MEP undergo fate specification to the megakaryocytic and erythroid lineages.
Lab link: https://krauselab.net/members/rubia/
Leibold Abstract Type A P&F 2024
Regulation of cellular iron content is crucial: excess cellular iron catalyzes the generation of reactive oxygen species (ROS) that damage DNA and proteins, while cellular iron deficiency causes cell cycle arrest and cell death. Dysregulation of iron homeostasis caused by iron deficiency or iron excess leads to common hematological, neurodegenerative and metabolic disorders. Vertebrate iron metabolism is controlled post-transcriptionally by iron-regulatory protein 2 (Irp2). Irp2 binds to iron-responsive elements (IREs) in the mRNAs of proteins involved in iron uptake (transferrin receptor 1, TfR1), sequestration (ferritin) and export (ferroportin), and regulates the translation or stability of these mRNAs. Our previous work show that Irp2 is regulated by iron-dependent proteolysis by the FBXL5 SCF-ubiquitin ligase. We also discovered a novel iron-independent mechanism for regulating Irp2 RNA-binding activity during the cell cycle. Irp2 is phosphorylated at serine157 by Cdk1/cyclin B during G2/M and dephosphorylated by Cdc14A at mitotic exit. S157 phosphorylation inhibits Irp2 RNA-binding activity during mitosis to increase ferritin and decrease TfR1 expression. Our studies show that expression of a Irp2-S157A mutant in Irp2-deficient mouse embryonic fibroblasts causes a G2/M delay and slows proliferation. The physiological significance of S157 phosphorylation was investigated in mice where S157 was mutated to Ala157 (Irp2A/A)). Irp2A/A mice display normocytic normochromic anemia, dysregulated systemic iron metabolism, defective erythroid terminal differentiation and splenomegaly. Analysis of the proteome in WT and Ter119+ cells reveals significant changes in metabolic enzymes and other proteins in Irp2A/A Ter119+ cells, suggesting that metabolites are altered in Irp2A/A Ter119+ cells. Our objective here is to characterize the metabolomes of WT and Irp2A/A Ter119+ erythroblasts. These studies will provide a comprehensive view of the proteome and metabolome of erythropoiesis in WT and Irp2A/A mice. For these studies, we propose to utilize the University of Utah Center for Iron & Heme Disorders Core (CIHD) Metabolomics Core for metabolomic analyses.