Transcription Factor Regulatory Networks Governing Erythropoiesis in Iron Deficiency States: An Original Systems Biology Approach Using Nigerian Patient-Derived Erythroid Cultures

This dissertation applies an original systems biology approach to map transcription factor regulatory networks governing erythropoiesis under iron deficiency conditions using patient-derived erythroid cultures from Nigerian iron deficiency anaemia patients at Aminu Kano Teaching Hospital, North West Nigeria. Iron deficiency globally suppresses erythropoiesis, but the transcriptional regulatory architecture mediating the erythroid response to iron limitation in African genetic contexts has not been systematically characterised using network-level analysis. CD34+ haematopoietic stem and progenitor cells were isolated from 30 confirmed iron deficiency anaemia patients and 20 iron-replete controls. In vitro erythroid differentiation was performed under varying iron concentrations (0, 10, 50, and 200 micromolar ferric ammonium citrate). RNA sequencing was performed at four differentiation timepoints. Transcription factor regulatory network reconstruction used SCENIC and VIPER network analysis tools. CUT&RUN for GATA1, KLF1, and HEME-regulated inhibitor kinase (HRI) was performed to validate regulatory interactions. The dissertation identifies an original HRI-eIF2alpha-ATF4 axis as the master regulatory hub coordinating transcriptional adaptation to iron deficiency in erythroid progenitors from Nigerian patients, diverging from compensatory activation patterns described in murine models. ATF4 target gene activation drove stress erythropoiesis programmes rather than classical hypoxia-inducible factor pathways. A dynamic transcription factor network model is proposed as an original theoretical contribution for understanding erythropoietic adaptation in African iron deficiency populations. Keywords: erythropoiesis, transcription factor networks, iron deficiency, systems biology, Nigeria.