Macias-Garcia, A. | bioRxiv Science

bioRxiv2026

DCN1 inhibitor induces fetal hemoglobin through self-limited regulation of CUL3 neddylation

Few genetic loci are as well-characterized as the globin gene locus, and the substitution of healthy {gamma}-globin (HbF) for missing or mutated {beta}-globin (HbB) is an established therapeutic strategy for {beta}-hemoglobinopathies including sickle cell disease (SCD) and {beta}-thalassemia. Although substantial progress has been made in understanding HbF derepression and globin switching, many current therapeutic strategies involving small molecules increase HbF through broad epigenetic perturbations or cytotoxic stress, raising concerns about dose-limiting cytopenias and off-target effects. By coupling single-cell transcriptomics, genetic perturbations, and functional genomics, we identified an unknown role of neddylation in the regulation of fetal hemoglobin (HbF). Partial impairment of neddylation of cullin ubiquitin ligase 3 (CUL3) through defective in cullin neddylation 1 (DCN1) inhibition leads to highly selective chromatin changes, histone demethylation, and globin locus binding of known activators of HbF transcription. Further, DCN1 inhibition drives globin switching and HbF increases in vitro and in vivo with minimal off-target transcriptional effects and no evidence of cytotoxicity or stress erythropoiesis. To therapeutically target this axis, we report the discovery and characterization of CLY-124, a first-in-class, covalent DCN1 inhibitor with favorable pharmacology properties. In a humanized mouse model, CLY-124 showed a dose-dependent increase in HbF as monotherapy and in synergy with hydroxyurea (HU), a current standard of care. Collectively, these findings highlight the power of single-cell transcriptomics to elucidate undiscovered biologic insights with therapeutic potential, and the promise of DCN-1 inhibitors like CLY-124 to address {beta}-hemoglobinopathies. With an appropriate nonclinical safety profile, a first-in human study of safety, pharmacokinetics and HbF assessments in healthy volunteers and participants with SCD is ongoing for CLY-124. One-sentence SummaryDCN1 is a promising target for {beta}-hemoglobinopathies

molecular biology↗

bioRxiv2018

Iron and Heme Coordinate Erythropoiesis through HRI-Mediated Regulation of Protein Translation and Gene Expression

Iron and heme play central roles in red blood cell production. However, the mechanisms by which iron and heme levels coordinate erythropoiesis remain incompletely understood. HRI is a heme-regulated kinase that controls translation by phosphorylating eIF2. Here, we investigate the global impact of iron, heme and HRI on protein translation in vivo in murine primary erythroblasts using ribosome profiling. By defining the underlying changes in translation during iron and HRI deficiencies, we validate known regulators of this process, including Atf4, and identify novel pathways such as co-regulation of ribosomal protein mRNA translation. Surprisingly, we found that heme and HRI pathways, but not iron-regulated pathways, mediate the major protein translational and transcriptional responses to iron deficiency in erythroblasts in vivo and thereby identify previously unappreciated regulators of erythropoiesis. Our genome-wide study uncovers the major impact of the HRI-mediated integrated stress response for the adaptation to iron deficiency anemia.

cell biology↗