Erythroid lineage chromatin accessibility maps facilitate identification and validation of NFIX as a fetal hemoglobin repressor

Chaand, Mudit; Fiore, Christopher; Johnston, Brian T.; D’Ippolito, Anthony; Moon, Diane H.; Carulli, John P.; Shearstone, Jeffrey R.

doi:10.1038/s42003-023-05025-4

Cited by 3 publications

(1 citation statement)

References 61 publications

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“…Importantly, the expression of the known erythroid fetal gene SOX6, was only detected in definitive and FL RBCs ( supplemental Figure 4 H), as was increased expression of genes involved in globin switching such as ZBTB7A 52 and NFI-factors. 53 , 54 …”

Section: Resultsmentioning

confidence: 99%

Modeling primitive and definitive erythropoiesis with induced pluripotent stem cells

Pavani,

Klein,

Nations

et al. 2024

Blood Advances

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During development, erythroid cells are produced through at least two distinct hematopoietic waves (primitive and definitive), generating erythroblasts with different functional characteristics. Human induced pluripotent stem cells (iPSCs) can be used as a model platform to study red blood cell (RBC) development with many of the differentiation protocols following the primitive wave of hematopoiesis. Recent advances have established that definitive hematopoietic progenitors can be generated from iPSCs, creating a unique situation for comparing primitive and definitive erythrocytes derived from cell sources of identical genetic background. We generated iPSCs from healthy fetal liver (FL) cells and produced isogenic primitive or definitive RBCs which were compared directly to the FL-derived RBCs. Functional assays confirmed differences between the two programs, with primitive RBCs showing a reduced proliferation potential, larger cell size, lack of Duffy RBC antigen expression, and higher expression of embryonic globins. Transcriptome profiling by scRNA-seq demonstrated high similarity between FL- and iPSC-derived definitive RBCs along with very different gene expression and regulatory network patterns for primitive RBCs. In addition, iPSC lines harboring a known pathogenic mutation in the erythroid master regulator KLF1 demonstrated phenotypic changes specific to definitive RBCs. Our studies provide new insights into differences between primitive and definitive erythropoiesis and highlight the importance of ontology when using iPSCs to model genetic hematologic diseases. Beyond disease modeling, the similarity between FL- and iPSC-derived definitive RBCs expands potential applications of definitive RBCs for diagnostic and transfusion products.

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Section: Resultsmentioning

confidence: 99%

Modeling primitive and definitive erythropoiesis with induced pluripotent stem cells

Pavani,

Klein,

Nations

et al. 2024

Blood Advances

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Elevating fetal hemoglobin: recently discovered regulators and mechanisms

Khandros,

Blobel

2024

Blood

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It has been known for over half a century that humans produce different forms of hemoglobin, a tetramer of α- and β-like hemoglobin chains, throughout ontogeny. The switch from fetal to adult hemoglobin occurs around the time of birth when erythropoiesis shifts from the fetal liver to the bone marrow. Naturally, diseases caused by defective adult β-globin genes, such as sickle cell disease and β-thalassemia manifest themselves as production of fetal hemoglobin fades. Reversal of this developmental switch has been a major goal to treat these diseases and has been a driving force to understand its underlying molecular biology. Several review articles have illustrated the long and at times arduous paths that led to the discovery of the first transcriptional regulators involved in this process. Here we survey recent developments, spurred by the discovery of CRISPR tools that enabled for the first time high throughput genetic screens for new molecules that impact the fetal to adult hemoglobin switch. Numerous opportunities for therapeutic intervention thus came to light, offering hope for effective pharmacologic intervention for patients for whom gene therapy is out of reach.

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Post-GWAS Validation of Target Genes Associated with HbF and HbA2 Levels

Caria,

Faà,

Porcu

et al. 2024

Cells

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Genome-Wide Association Studies (GWASs) have identified a huge number of variants associated with different traits. However, their validation through in vitro and in vivo studies often lags well behind their identification. For variants associated with traits or diseases of biomedical interest, this gap delays the development of possible therapies. This issue also impacts beta-hemoglobinopathies, such as beta-thalassemia and sickle cell disease (SCD). The definitive cures for these diseases are currently bone marrow transplantation and gene therapy. However, limitations regarding their effective use restrict their worldwide application. Great efforts have been made to identify whether modulators of fetal hemoglobin (HbF) and, to a lesser extent, hemoglobin A2 (HbA2) are possible therapeutic targets. Herein, we performed the post-GWAS in vivo validation of two genes, cyclin D3 (CCND3) and nuclear factor I X (NFIX), previously associated with HbF and HbA2 levels. The absence of Ccnd3 expression in vivo significantly increased g (HbF) and d (HbA2) globin gene expression. Our data suggest that CCND3 is a possible therapeutic target in sickle cell disease. We also confirmed the association of Nfix with γ-globin gene expression and present data suggesting a possible role for Nfix in regulating Kruppel-like transcription factor 1 (Klf1), a master regulator of hemoglobin switching. This study contributes to filling the gap between GWAS variant identification and target validation for beta-hemoglobinopathies.

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Erythroid lineage chromatin accessibility maps facilitate identification and validation of NFIX as a fetal hemoglobin repressor

Cited by 3 publications

References 61 publications

Modeling primitive and definitive erythropoiesis with induced pluripotent stem cells

Modeling primitive and definitive erythropoiesis with induced pluripotent stem cells

Elevating fetal hemoglobin: recently discovered regulators and mechanisms

Post-GWAS Validation of Target Genes Associated with HbF and HbA2 Levels

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