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Clucas, D.

Publications and source records attributed to Clucas, D..

3 recordsLinked to original sources

Regulation of Human Erythroferrone Expression

Erythroferrone (ERFE) is an erythroblast-secreted hormone that suppresses hepatic hepcidin expression to increase iron availability for erythropoiesis, ensuring recovery from anaemia. ERFE excess drives iron overload in disorders of ineffective erythropoiesis. Despite its pivotal role in systemic iron homeostasis and diseases of erythropoiesis, ERFEs molecular regulation has remained undefined. Here, we applied a genomic approach to characterise the molecular mechanisms governing ERFE expression. Using the HUDEP-2 human erythroid progenitor model, integrative ATAC-seq, CUT&RUN and micro capture-C analysis we identified a stage-specific accessible chromatin region within the ERFE 3 UTR that interacts with the promotor. We also identified enhancer-associated chromatin marks including H3K4me1 and H3K27ac in this region, and demonstrate that this cis-regulatory element is bound by key erythroid transcription factors KLF1, GATA1, TAL1 and STAT5. Functional dissection using CRISPR-Cas9-mediated deletion of the central 3 UTR enhancer element led to marked reduction in ERFE mRNA expression, and we show a corresponding reduction in nascent mRNA, confirming a key role for this region in transcriptional regulation. We define the transcriptional regulatory mechanism by which maturing human erythroblasts activate ERFE, the endocrine signal that coordinates erythropoietic demand with systemic iron mobilisation.

molecular biology↗

Host iron deficiency protects against Plasmodium infection and drives parasite molecular reprofiling.

Iron deficiency, anemia and Plasmodium infection represent significant global health challenges with overlapping geographical distributions, particularly affecting pregnant women in Africa, yet the mechanisms underlying their interactions remain poorly understood. We employed a multilayered approach combining clinical data from Malawian pregnant women (n=711) in the REVAMP trial, a genetic mouse model (Tmprss6-knockout), and in vitro P. falciparum cultures to clarify associations between iron status and malaria susceptibility. Iron deficiency was associated with 50% reduced P. falciparum parasitemia in pregnant women (95% CI [30%-64%], p<0.0001), while iron-deficient mice exhibited significantly improved survival against P. berghei (median 15.5 days vs. 7.0 days for WT mice) and protection from cerebral malaria (83% vs 17% survival). Iron chelation induced substantial transcriptomic and proteomic changes in cultured parasites, affecting host cell invasion and nutrient acquisition processes. Importantly, intravenous iron supplementation did not increase subsequent parasitemia when coupled with malaria prevention. These findings demonstrate that iron deficiency protects against Plasmodium infection and support WHO recommendations for iron supplementation in malaria-endemic regions when combined with adequate malaria prevention strategies.

cell biology↗

Iron homeostasis governs erythroid phenotype in Polycythemia Vera

Polycythemia Vera (PV) is a myeloproliferative neoplasm driven by activating mutations in JAK2 that result in unrestrained erythrocyte production, increasing patients hematocrit and hemoglobin concentration, placing them at risk of life-threatening thrombotic events. Our GWAS of 440 PV cases and 403,351 controls utilising UK Biobank data found that SNPs in HFE known to cause hemochromatosis are highly associated with PV diagnosis, linking iron regulation to PV. Analysis of the FinnGen dataset independently confirmed over-representation of homozygous HFE mutations in PV patients. HFE influences expression of hepcidin, the master regulator of systemic iron homeostasis. Through genetic dissection of PV mouse models, we show that the PV erythroid phenotype is directly linked to hepcidin expression: endogenous hepcidin upregulation alleviates erythroid disease whereas hepcidin ablation worsens it. Further, we demonstrate that in PV, hepcidin is not regulated by expanded erythropoiesis but is likely governed by inflammatory cytokines signalling via GP130 coupled receptors. These findings have important implications for understanding the pathophysiology of PV and offer new therapeutic strategies for this disease.

cancer biology↗