Kim, Juyoung2022-09-262022-09-262022-01https://hdl.handle.net/11299/241736University of Minnesota Ph.D. dissertation. January 2022. Major: Nutrition. Advisor: Moon-Suhn Ryu. 1 computer file (PDF); xi, 162 pages.Zinc is an essential trace element for various biological processes in the body. Cellular zinc homeostasis is established via differential expressions of the cell-type-specific zinc transporters, ZnTs and ZIPs. Zinc deficiency in humans has been associated with anemia. Yet, molecular mechanisms by which zinc alters red blood cell development remain uncertain. The current studies elucidate the roles of cellular zinc during red blood cell development and identify a zinc transporter important in maintaining erythroid zinc homeostasis during terminal erythroid differentiation and zinc deficiency.G1E-ER4 and MEL cells were employed for the characterization of the roles of zinc and zinc transporter in terminal erythroid differentiation and heme biosynthesis. G1E-ER4 cells featured a 1.7-fold increase in total cellular zinc contents after 48-hour of differentiation. Acute zinc depletion by a membrane-permeable chelator TPEN resulted in a rapid loss in cell viability. Restriction of extracellular zinc supply using a membrane-impermeable zinc chelator DTPA impaired hemoglobinization of differentiating G1E-ER4 cells without a significant loss in cell viability. The decreased heme contents by DTPA were fully restored by replenishing equimolar zinc and were not due to changes in total cellular iron contents. Zinc-deficient G1E-ER4 cells differentiated with normal Alas2 transcript response but less Alad and alpha-globin mRNA abundance. Deficiency of the heme precursor metabolite, protoporphyrin, was observed in MEL cells experiencing heme deficiency due to restricted zinc supply. Among the 24 zinc transporter genes, Zip10 was identified as most responsive to cellular zinc deficiency in developing G1E-ER4 cells. Moreover, the upregulation of ZIP10 was found essential for adequate hemoglobin production when cellular zinc supply was restricted. Through screening of the gnomAD database, we have identified three missense ZIP10 variants specifically polymorphic among the African population. The presence of these polymorphisms was experimentally confirmed by genotyping genomic DNA from African individuals. The current studies characterize zinc as a nutrient essential to proper erythroid maturation and heme biosynthesis and identify a compensatory role of ZIP10 for erythroid zinc homeostasis under zinc restriction. The findings suggest that poor zinc status and ZIP10 mutations might serve as potential risk factors and are expected to be new therapeutic targets for erythrocyte-related disorders, including anemia.enErythroid progenitorHeme synthesisSLC39A10/ZIP10ZincZinc transporterThesis or Dissertation