Disrupting the adult-globin promoter alleviates promoter competition and reactivates foetal-globin gene expression
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA798972 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR17679178_1.fastq.gz | Fastqsanger.gz | |||
| SRR17679178_2.fastq.gz | Fastqsanger.gz | |||
| SRR17679179_1.fastq.gz | Fastqsanger.gz | |||
| SRR17679179_2.fastq.gz | Fastqsanger.gz | |||
| SRR17679180_1.fastq.gz | Fastqsanger.gz |
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Project description:The benign condition Hereditary Persistence of Foetal Haemoglobin (HPFH) is known to ameliorate symptoms when co-inherited with beta-haemoglobinopathies, such as sickle cell disease and beta-thalassaemia. The condition is sometimes associated with point mutations in the foetal globin promoters that disrupt the binding of the repressors BCL11A or ZBTB7A/LRF, which have been extensively studied. HPFH is also associated with a range of deletions within the beta-globin locus that all reside downstream of the foetal HBG2 gene. These deletional forms of HPFH are poorly understood and are the focus of this study. Numerous different mechanisms have been proposed to explain how downstream deletions can boost the expression of the foetal globin genes, including the deletion of silencer elements, of genes encoding non-coding RNA, and bringing downstream enhancer elements into proximity with the foetal globin gene promoters. Here we systematically analyse the deletions associated with both HPFH and a related condition known as beta-thalassaemia and propose a unifying mechanism. In all cases where foetal globin is up-regulated, the proximal adult beta-globin (HBB) promoter is deleted. We use CRISPR gene editing to delete or disrupt elements within the promoter and find that virtually all mutations that reduce promoter activity, result in elevated foetal globin expression. These results fit with previous models where the foetal and adult globin genes compete for the distal Locus Control Region and suggest that targeting the promoter might be explored to elevate foetal globin and reduce sickle globin expression as a treatment for beta-haemoglobinopathies.
2022-01-20 | GSE194064 | GEO
Project description:The benign condition hereditary persistence of fetal hemoglobin (HPFH) is known to ameliorate symptoms of co-inherited β-hemoglobinopathies, such as sickle cell disease and β-thalassemia. The condition is sometimes associated with point mutations in the fetal globin promoters that disrupt the binding of the repressors BCL11A or ZBTB7A/LRF, which have been extensively studied. HPFH is also associated with a range of deletions within the β-globin locus that all reside downstream of the fetal HBG2 gene. These deletional forms of HPFH are poorly understood and are the focus of this study. Numerous different mechanisms have been proposed to explain how downstream deletions can boost the expression of the fetal globin genes, including the deletion of silencer elements, of genes encoding noncoding RNA, and bringing downstream enhancer elements into proximity with the fetal globin gene promoters. Here we systematically analyze the deletions associated with both HPFH and a related condition known as δβ-thalassemia and propose a unifying mechanism. In all cases where fetal globin is upregulated, the proximal adult β-globin (HBB) promoter is deleted. We use clustered regularly interspaced short palindromic repeats-mediated gene editing to delete or disrupt elements within the promoter and find that virtually all mutations that reduce ΗΒΒ promoter activity result in elevated fetal globin expression. These results fit with previous models where the fetal and adult globin genes compete for the distal locus control region and suggest that targeting the ΗΒΒ promoter might be explored to elevate fetal globin and reduce sickle globin expression as a treatment of β-hemoglobinopathies.
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Project description:A one-base therapeutic insertion in the HBG2 distal promoter reactivates γ-globin expression
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Project description:The fetal-to-adult hemoglobin switch is regulated in a developmental stage-specific manner and reactivation of fetal hemoglobin (HbF) has therapeutic potential for β-hemoglobinopathies. Although BCL11A and ZBTB7A interact with their coregulators, reportedly mediating most γ-globin transcriptional silencing in erythroid in trans, and in cis, the molecular mechanism underlying the epigenetic dysregulation of the switch remains largely unclear. Here we showed that epigenetic inactivation of an ETS2 repressor factor (ERF) reactivates γ-globin expression during stress erythropoiesis, and ERF depletion elevates γ-globin in erythroid cells and in erythroid progenies from the edited HSPCs engrafted into immunodeficient mice. ERF represses γ-globin by directly binding to two motifs regulating HBG expression, independently of the major HbF repressors BCL11A and ZBTB7A. We further uncovered that an lncRNA, RP11-196G18.23 mediates ERF promoter hypermethylation resulting in reactivation of g-globin. Herein, the epigenetic alterations were identified as novel modulators ameliorating the severity of b-thalassemia, thus providing novel therapeutic targets for β-hemoglobinopathies.
2020-12-27 | GSE160602 | GEO
Project description:The fetal-to-adult hemoglobin switch is regulated in a developmental stage-specific manner and reactivation of fetal hemoglobin (HbF) has therapeutic potential for β-hemoglobinopathies. Although BCL11A and ZBTB7A interact with their coregulators, reportedly mediating most γ-globin transcriptional silencing in erythroid in trans, and in cis, the molecular mechanism underlying the epigenetic dysregulation of the switch remains largely unclear. Here we showed that epigenetic inactivation of an ETS2 repressor factor (ERF) reactivates γ-globin expression during stress erythropoiesis, and ERF depletion elevates γ-globin in erythroid cells and in erythroid progenies from the edited HSPCs engrafted into immunodeficient mice. ERF represses γ-globin by directly binding to two motifs regulating HBG expression, independently of the major HbF repressors BCL11A and ZBTB7A. We further uncovered that an lncRNA, RP11-196G18.23 mediates ERF promoter hypermethylation resulting in reactivation of g-globin. Herein, the epigenetic alterations were identified as novel modulators ameliorating the severity of b-thalassemia, thus providing novel therapeutic targets for β-hemoglobinopathies.
2020-12-27 | GSE160601 | GEO
Project description:The reactivation of developmental silenced g-globin genes (HBG1/2) has shown promise as a therapeutic strategy for improving symptoms of b-hemoglobinopathies. Currently, the focus of therapeutic targets is primarily on the major fetal hemoglobin suppressors, such as BCL11A and ZBTB7A and of their binding sites on the proximal HBG promoter. However, the role of the distal HBG promoter in regulating gene expression remains to be explored. Here, we discovered an insertion of nucleotide A (insA) between -1368 and -1369 bp upstream of the TSS in HBG2 resulting in remarkable increase in γ-globin expression in HUDEP-2 cells. We also observed elevated γ-globin expression in human CD34+ erythroid progenitor cells from healthy individuals and those with b-thalassemia when introducing insA mutation. Similarly, engrafted NCG-Kit-V831M mice showed increased γ-globin expression. Importantly, neither did insA have any off-target effects nor did it affect the maturation of erythroid cells. Furthermore, we found that the insA mutation created a binding site for the transcription activator FOXO3, which can reactivate g-globin. Additionally, introducing insA specifically and significantly demethylated the -162 CpG site on HBG promoter by reducing the enrichment of DNA methyltransferase 3A (DNMT3A). At the same time, it activated histone modifications and RNA polymerase II (Pol II) in both distal and proximal HBG promoter and inhibited the binding of BCL11A and ZBTB7A on -115 and -200 sites on the HBG promoter respectively. Overall, our study suggests that introducing insA mutation leads to significantly boosted fetal globin levels and uncovers new safe therapeutic target or strategy for β-hemoglobinopathies.
2025-04-02 | GSE283117 | GEO
Project description:The reactivation of developmental silenced g-globin genes (HBG1/2) has shown promise as a therapeutic strategy for improving symptoms of b-hemoglobinopathies. Currently, the focus of therapeutic targets is primarily on the major fetal hemoglobin suppressors, such as BCL11A and ZBTB7A and of their binding sites on the proximal HBG promoter. However, the role of the distal HBG promoter in regulating gene expression remains to be explored. Here, we discovered an insertion of nucleotide A (insA) between -1368 and -1369 bp upstream of the TSS in HBG2 resulting in remarkable increase in γ-globin expression in HUDEP-2 cells. We also observed elevated γ-globin expression in human CD34+ erythroid progenitor cells from healthy individuals and those with b-thalassemia when introducing insA mutation. Similarly, engrafted NCG-Kit-V831M mice showed increased γ-globin expression. Importantly, neither did insA have any off-target effects nor did it affect the maturation of erythroid cells. Furthermore, we found that the insA mutation created a binding site for the transcription activator FOXO3, which can reactivate g-globin. Additionally, introducing insA specifically and significantly demethylated the -162 CpG site on HBG promoter by reducing the enrichment of DNA methyltransferase 3A (DNMT3A). At the same time, it activated histone modifications and RNA polymerase II (Pol II) in both distal and proximal HBG promoter and inhibited the binding of BCL11A and ZBTB7A on -115 and -200 sites on the HBG promoter respectively. Overall, our study suggests that introducing insA mutation leads to significantly boosted fetal globin levels and uncovers new safe therapeutic target or strategy for β-hemoglobinopathies.
2025-04-02 | GSE262797 | GEO
Project description:The reactivation of developmental silenced g-globin genes (HBG1/2) has shown promise as a therapeutic strategy for improving symptoms of b-hemoglobinopathies. Currently, the focus of therapeutic targets is primarily on the major fetal hemoglobin suppressors, such as BCL11A and ZBTB7A and of their binding sites on the proximal HBG promoter. However, the role of the distal HBG promoter in regulating gene expression remains to be explored. Here, we discovered an insertion of nucleotide A (insA) between -1368 and -1369 bp upstream of the TSS in HBG2 resulting in remarkable increase in γ-globin expression in HUDEP-2 cells. We also observed elevated γ-globin expression in human CD34+ erythroid progenitor cells from healthy individuals and those with b-thalassemia when introducing insA mutation. Similarly, engrafted NCG-Kit-V831M mice showed increased γ-globin expression. Importantly, neither did insA have any off-target effects nor did it affect the maturation of erythroid cells. Furthermore, we found that the insA mutation created a binding site for the transcription activator FOXO3, which can reactivate g-globin. Additionally, introducing insA specifically and significantly demethylated the -162 CpG site on HBG promoter by reducing the enrichment of DNA methyltransferase 3A (DNMT3A). At the same time, it activated histone modifications and RNA polymerase II (Pol II) in both distal and proximal HBG promoter and inhibited the binding of BCL11A and ZBTB7A on -115 and -200 sites on the HBG promoter respectively. Overall, our study suggests that introducing insA mutation leads to significantly boosted fetal globin levels and uncovers new safe therapeutic target or strategy for β-hemoglobinopathies.
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Project description:A one-base therapeutic insertion in the HBG2 distal promoter reactivates γ-globin expression [RNA-Seq]
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Project description:A one-base therapeutic insertion in the HBG2 distal promoter reactivates γ-globin expression [ChIP-Seq]
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