Domain-focused CRISPR-screen identifies HRI as a fetal hemoglobin regulator in human erythroid cells
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ABSTRACT:
PROVIDER: PRJNA475769 | ENA |
REPOSITORIES: ENA
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Project description:Increasing fetal hemoglobin (HbF) levels in adult red blood cells provides clinical benefit to patients with sickle cell disease and some forms of beta-thalassemia. To identify potentially druggable HbF regulators in adult human erythroid cells, we employed a protein kinase-domain focused CRISPR/Cas9-based genetic screen with a newly optimized sgRNA scaffold. The screen uncovered the heme-regulated inhibitor HRI (also known as EIF2AK1), an erythroid-specific kinase that controls protein translation, as an HbF repressor. HRI depletion markedly increased HbF production in a specific manner and reduced sickling in cultured erythroid cells. Diminished expression of the HbF repressor BCL11A accounted in large part for the effects of HRI depletion. Taken together, these results suggest HRI as a potential therapeutic target for hemoglobinopathies.
2018-07-20 | GSE115687 | GEO
Project description:Increasing fetal hemoglobin (HbF) provides clinical benefit in patients with sickle cell disease (SCD). We recently identified heme-regulated inhibitor (HRI, EIF2AK1) as a novel HbF regulator. Since HRI is an erythroid-specific protein kinase it presents a potential target for pharmacologic intervention. We find that maximal HbF induction requires >80-85% HRI depletion. As it remains unclear whether this degree of HRI inhibition can be achieved pharmacologically, we explored whether HRI knockdown can be combined with pharmacologic HbF inducers to achieve greater HbF production and minimize potential adverse effects associated with treatments. Strongly cooperative HbF induction was observed when HRI depletion was combined with exposure to pomalidomide or the EHMT1/2 inhibitor UNC0638, but not hydroxyurea. Mechanistically, reduction in the levels of the HbF repressor BCL11A reflected the cooperativity of HRI loss and pomalidomide treatment, whereas UNC0638 did not modulate BCL11A levels. In conjunction with HRI loss, pomalidomide maintained its HbF inducing activity at 10-fold lower concentrations, at which condition there were minimal observed detrimental effects on erythroid cell maturation and viability as well as fewer alterations in the erythroid transcriptome. In sum, this study provides a foundation for the exploration of combining future small molecule HRI inhibitors with additional pharmacologic HbF inducers to maximize HbF production and preserve erythroid cell functionality for the treatment of SCD and other hemoglobinopathies.
2020-09-21 | GSE150341 | GEO
Project description: Not available
| S-EPMC6257981 | biostudies-literature
Project description:Through a CRISPR-Cas9 guided loss-of-function screen in human erythroid cells we identified transcription factor ATF4, a known HRI-regulated protein, as a novel γ-globin repressor. ATF4 binds to a BCL11A enhancer to augment promoter contacts, stimulates BCL11A transcription to repress γ-globin expression. Notably, mice deficient for HRI displayed normal Bcl11a levels, suggesting species selective regulation that we explain here by demonstrating that the analogous ATF4 motif at the murine Bcl11a enhancer is largely dispensable. This illustrates potential limits of commonly used murine models of globin gene regulation.
2020-04-17 | GSE143962 | GEO
Project description:Through a CRISPR-Cas9 guided loss-of-function screen in human erythroid cells we identified transcription factor ATF4, a known HRI-regulated protein, as a novel γ-globin repressor. ATF4 binds to a BCL11A enhancer to augment promoter contacts, stimulates BCL11A transcription to repress γ-globin expression. Notably, mice deficient for HRI displayed normal Bcl11a levels, suggesting species selective regulation that we explain here by demonstrating that the analogous ATF4 motif at the murine Bcl11a enhancer is largely dispensable. This illustrates potential limits of commonly used murine models of globin gene regulation.
2020-04-17 | GSE143961 | GEO
Project description:Heme-regulated eIF2α kinase (HRI) is essential for the survival of erythroid precursors in iron and heme deficiency and it also plays a protective role in red blood cell diseases of erythroid protoporphyria and β-thalassemia. In this study, we demonstrated for the first time the impairment of GATA-1 and Fog-1 expressions in iron deficiency and the impairment of GATA-1 expression in β-thalassemia. Furthermore, HRI is necessary to maintain the GATA-1/Fog-1 induced functions in erythroid differentiation, cell cycle and cell survival by sustaining both expressions of GATA-1 and Fog-1 in iron deficiency and in β-thalassemia. Keywords: Genetic modification
2009-06-30 | GSE6808 | GEO
Project description:HRI activates ATF4 to promote BCL11A transcription and fetal hemoglobin silencing
| PRJNA602341 | ENA
Project description:Gene expression profiling was performed on primary human erythroid progenitor cells left untreated or treated with 0.5uM SAHA. The worldwide burden of sickle cell disease is enormous, with over 200,000 infants born with the disease each year in Africa alone. Induction of fetal hemoglobin is a validated strategy to improve symptoms and complications of this disease. The development of targeted therapies has been limited by the absence of discrete druggable targets. We developed a novel bead-based strategy for the identification of inducers of fetal hemoglobin transcripts in primary human erythroid cells. A small-molecule screen of bioactive compounds identified remarkable class-associated activity among histone deacetylase (HDAC) inhibitors. Using a chemical genetic strategy combining focused libraries of biased chemical probes and reverse genetics by RNA interference, we have identified HDAC1 and HDAC2 as molecular targets mediating fetal hemoglobin induction. Our findings suggest the potential of isoform-selective inhibitors of HDAC1 and HDAC2 for the treatment of sickle cell disease. Gene expression profiling was performed on primary human erythroid progenitor cells left untreated (n=3) or treated with 0.5uM SAHA (n=3).
2010-07-29 | E-GEOD-22367 | biostudies-arrayexpress
Project description:Gene expression profiling was performed on primary human erythroid progenitor cells left untreated or treated with 2uM NK57 for 3 days. The worldwide burden of sickle cell disease is enormous, with over 200,000 infants born with the disease each year in Africa alone. Induction of fetal hemoglobin is a validated strategy to improve symptoms and complications of this disease. The development of targeted therapies has been limited by the absence of discrete druggable targets. We developed a novel bead-based strategy for the identification of inducers of fetal hemoglobin transcripts in primary human erythroid cells. A small-molecule screen of bioactive compounds identified remarkable class-associated activity among histone deacetylase (HDAC) inhibitors. Using a chemical genetic strategy combining focused libraries of biased chemical probes and reverse genetics by RNA interference, we have identified HDAC1 and HDAC2 as molecular targets mediating fetal hemoglobin induction. Our findings suggest the potential of isoform-selective inhibitors of HDAC1 and HDAC2 for the treatment of sickle cell disease. Gene expression profiling was performed on primary human erythroid progenitor cells left untreated (n=7) or treated with 2uM NK57 for 3 days (n=2).
2010-07-29 | E-GEOD-22368 | biostudies-arrayexpress
Project description:HRI activates ATF4 to promote BCL11A transcription and fetal hemoglobin silencing [Capture-C]
| PRJNA602343 | ENA