scholarly journals Potentially therapeutic levels of anti-sickling globin gene expression following lentivirus-mediated gene transfer in sickle cell disease bone marrow CD34 + cells

2015 ◽  
Vol 43 (5) ◽  
pp. 346-351 ◽  
Author(s):  
Fabrizia Urbinati ◽  
Phillip W. Hargrove ◽  
Sabine Geiger ◽  
Zulema Romero ◽  
Jennifer Wherley ◽  
...  
Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3506-3506
Author(s):  
Jianqiong Zhu ◽  
Kyung Chin ◽  
Wulin Aerbajinai ◽  
Chutima Kumkhaek ◽  
Hongzhen Li ◽  
...  

Abstract Current gene therapy approaches for treatment of hemoglobinopathies involve viral transduction of hematopoietic stem cells with antisickling globin genes. Hemoglobin A2 (HA2, α2δ2), expressed at a low level due to the lack of Eklf binding motif in its promoter region, is fully functional and could be a valid anti-sickling agent in sickle cell disease, as well as a substitute of hemoglobin A in β-thalassemia. We had previously demonstrated that two Eklf-GATA1 fusion proteins could significantly activate δ-globin expression in CD34+ cells from healthy and sickle trait donor's blood. Here we report the effects of Eklf-GATA1 on hemoglobin expression and phenotypic correction using erythrocytes cultured from CD34+ cells with sickle cell disease. We found that enforced expression of Eklf-GATA1 fusion protein enhanced globin gene expression in the erythrocytesas compared with vector control. The long-form Eklf-GATA1 up-regulated β-globin gene expression 2.0-fold, δ-globin gene expression 4.3-fold, and γ-globin gene expression 2.6-fold. The medium-form EKLF-GATA1 up-regulated δ-globin gene expression 2.3-fold and γ-globin 1.3-fold, but had no significant effect on β-globin gene expression. HPLC revealed a percentage of HA2+HbF was increased from 8.1 % in vector-transduced cells to 19.7% in medium-form Eklf-GATA-transduced-cells (p<0.01) and 14.4% in long-form Eklf-GATA-transduced-cells (p<0.01). Upon deoxygenation, the percentage of sickling erythrocyte was lower to 79.8% in medium-form Eklf-GATA-transduced cells as compared with 89.8% in vector-transduced-cells (p<0.05). Flow cytometry analyses of CD71/GPA and thiazole orange staining indicated that erythroid cell differentiation and enucleation were not affected by Eklf-GATA1. Our results shown that long form Eklf-GATA1 fusion protein has major effects on d- and g-globin induction than β-globin; the medium form Eklf-GATA1 elevated δ- and γ-globin expression without an effect on β-globin expression. Our results indicate that these fusion constructs could be a valuable genetic therapeutic tool for hemoglobinopathies, and warrant further preclinical study and evaluation. Disclosures No relevant conflicts of interest to declare.


Author(s):  
Susanna Porcu ◽  
Michela Simbula ◽  
Maria F. Marongiu ◽  
Andrea Perra ◽  
Daniela Poddie ◽  
...  

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1582-1582
Author(s):  
Donald Lavelle ◽  
Tatiana Kouznetsova ◽  
Kestis Vaitkus ◽  
Peter Larsen ◽  
Maria Hankewych ◽  
...  

Abstract The DNA demethylating drug decitabine increased fetal hemoglobin (HbF) to therapeutic levels and reduced the level of DNA methylation of the γ-globin gene promoter in patients with sickle cell disease and in experimental baboons. Whether decreased DNA methylation of the γ-globin gene is solely responsible for increased HbF following decitabine treatment is unknown. Increased platelet counts in patients with sickle cell disease and myelodysplastic syndrome and in experimental baboons following decitabine treatment suggest that decitabine also affects hematopoietic differentiation. To investigate to what extent the mechanism responsible for the ability of decitabine to reactivate HbF and alter hematopoietic differentiation may involve the induction of other unknown genes, the global pattern of gene expression in purified primary bone marrow erythroblasts pre- and post-decitabine treament was analyzed. Baboons were phlebotomized for ten days (Hct 20) followed by adminstration of decitabine for ten days (0.52mg/kg/d; sc). RNA was isolated from nucleated erythroblasts purified from bone marrow aspirates obtained pre- and post-decitabine treatment. Purification of erythroblasts was performed by sedimentation in Percoll gradients followed by immunomagnetic column purification using an anti-baboon RBC antibody (Pharmingen). To assess the feasibility of using human Genechip arrays to detect differences in expression of baboon transcripts, RNA isolated from purified erythroblasts of a single baboon pre- and post-decitabine was hybridized in triplicate to human Genechip Focus arrays (Affymetrix) containing over 8500 genes. The expression of 48 genes was increased >2 fold in the post-decitabine treated sample compared to the pre-treatment sample. Among the more highly induced genes were HLA-A (3 fold), HLA-B (5.7 fold), exportin 4 (3.9 fold), and splicing factor 3b1 (3.7 fold). Reverse transcriptase PCR using human primer sets was performed to analyze the expression of these genes in pre- and post-decitabine treated bone marrow erythroblasts in independent samples from three additional baboons. Induction of HLA-A, exportin 4, and splicing factor 3b1 was confirmed in all three post-decitabine treated samples. The exportin 4 gene encodes a protein involved in nuclear export of the Smad3 protein. Activated TGF-β receptors phosphorylate Smad3 and induce its nuclear import to affect gene transcription. Following dephosphorylation of Smad3 in the nucleus, transport of the protein to the cytoplasm mediated by exportin 4 has been proposed to allow the propagation of multiple rounds of activation by activated TGF-β receptors thus amplifying TGF-β signaling (Kurisaki et al; Mol Cell Biol26:1318, 2006). Because TGF-β increases HbF synthesis in cultured erythroid progenitors and also induces erythroid and megakaryocytic differentiation, we suggest that induction of exportin 4 by decitabine may play a role in the ability of this drug to increase HbF synthesis and alter hematopoietic differentiation. Our results thus confirm the feasibility of using human Genechip arrays to assess gene expression levels in baboons. Furthermore, we have indentified a gene induced by decitabine that potentially amplifies TGf-β signaling and thus may play a role in the ability of this drug to increase HbF and alter hematopoietic differentiation.


2013 ◽  
Vol 123 (8) ◽  
pp. 3317-3330 ◽  
Author(s):  
Zulema Romero ◽  
Fabrizia Urbinati ◽  
Sabine Geiger ◽  
Aaron R. Cooper ◽  
Jennifer Wherley ◽  
...  

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3479-3479
Author(s):  
Jianqiong Zhu ◽  
Hongzhen Li ◽  
Wulin Aerbajinai ◽  
Chutima Kumkhaek ◽  
Kyung Chin ◽  
...  

Abstract β-hemoglobinopathies are inherited disorders caused by mutations/deletions in the β-globin chain that lead to structurally defective β-globin chains or reduced (or absent) β-globin chain production. These diseases affect multiple organs and are associated with considerable morbidity and mortality, representing a major public health challenge. Current gene therapy approaches for the treatment of hemoglobinopathies involve viral transduction of hematopoietic stem cells with antisickling globin genes. Hemoglobin A2 (HA2, α2δ2), expressed at a low level due to the lack of Eklf binding motif in its promoter region, is fully functional and could be a valid anti-sickling agent in sickle cell disease, as well as a substitute of hemoglobin A in β-thalassemia. We had previously demonstrated that two Eklf-GATA1 fusion proteins could significantly activate δ-globin expression in human CD34+ cells. Here we report the effects of Eklf-GATA1 on hemoglobin expression and phenotypic correction using erythrocytes cultured from mouse hematopoietic progenitor cells with sickle cell disease. We found that enforced expression of Eklf-GATA1 fusion protein enhanced globin gene expression in the erythrocytesas compared with vector control. The long-form Eklf-GATA1 up-regulated β-globin gene expression 1.8-fold, δ-globin gene expression 3.3-fold, and γ-globin gene expression 1.7-fold. The medium-form EKLF-GATA1 up-regulated δ-globin gene expression 2.6-fold and γ-globin 1.3-fold, but had no significant effect on β-globin gene expression. HPLC revealed a percentage of HA2 was increased from 2.1 % in vector-transduced cells to 8.9% in medium-form Eklf-GATA-transduced-cells (p<0.01) and 6.3% in long-form Eklf-GATA-transduced-cells (p<0.01). Upon deoxygenation, the percentage of sickling erythrocyte was lower to 30.6% in medium-form Eklf-GATA-transduced cells as compared with 40.7% in vector-transduced-cells (p<0.05). Flow cytometry analyses of CD71/GPA and thiazole orange staining indicated that erythroid cell differentiation and enucleation were not affected by Eklf-GATA1. ChIP-sequencing analysis has demonstrated that Eklf-GATA1 fusion proteins and GATA1 having a similar protein-DNA binding pattern at a global level. Our results have found that the long form Eklf-GATA1 fusion protein has a major effect on δ-globin induction than β-globin; the medium form Eklf-GATA1 is able to elevate δ-globin expression without having an effect on β-globin expression. The above findings indicate that these fusion constructs could be a valuable genetic therapeutic tool for hemoglobinopathies, and warrant further preclinical study and evaluation. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 555-555 ◽  
Author(s):  
Hassana Fathallah ◽  
Ali Taher ◽  
Ali Bazarbachi ◽  
George F. Atweh

Abstract A number of therapeutic agents including hydroxyurea, butyrate and decitabine have shown considerable promise in the treatment of sickle cell disease (SCD). However, the same agents have shown less clinical activity in β-thalassemia. As a first step towards understanding the molecular basis of the different clinical responses to these agents, we have studied the mechanisms of induction of fetal hemoglobin (HbF) by butyrate in BFU-E derived cells from 5 patients with SCD and 9 patients with β-thalassemia intermedia. Exposure to butyrate resulted in a dose-dependent augmentation of γ-globin mRNA levels in erythroid cells from patients with SCD. In contrast, induction of γ-globin expression in erythroid cells from patients with β-thalassemia intermedia was only seen at a high concentration of butyrate. The increase in γ-globin mRNA levels in patients with SCD and β-thalassemia intermedia was associated with opening of the DNA structure as manifested by decreased DNA methylation at the γ-globin promoters. Interestingly, butyrate exposure had markedly different effects on the expression of the β- and α-globin genes in the two categories of patients. Butyrate decreased the level of β-globin mRNA in 4 out of 5 patients with SCD (P = 0.04), while in β-thalassemia the levels of β-globin mRNA did not change in 7 patients and decreased in 2 patients after butyrate exposure (P = 0.12). Thus in patients with SCD, the effects of the induction of the γ-globin gene on the γ/(β+γ) mRNA ratios were further enhanced by the butyrate-mediated decreased expression of the β-globin gene. As a result, γ/(β+γ) mRNA ratios increased in all patients with SCD, with a mean increase of 31% (P = 0.002). In contrast, butyrate increased γ/(β+γ) mRNA ratios only in 4 out of 9 patients with β-thalassemia, with a more modest mean increase of 12% (P = 0.004). Interestingly, the decreased β-globin expression in patients with SCD was associated with closing of the DNA configuration as manifested by hypermethylation of DNA at the promoter of the β-globin gene while methylation of the same promoter did not change following butyrate exposure in patients with β-thalassemia intermedia. More surprisingly, the expression of the α-globin genes increased following butyrate exposure in 4 out of 9 patients with β-thalassemia, while the levels of α-globin mRNA decreased in 4 out of 5 patients with SCD. As a result, the favorable effects of the butyrate-induced increase in γ-globin gene expression on the α: non-α mRNA imbalance in patients with β-thalassemia intermedia were partly neutralized by the corresponding increase in α-globin gene expression. These differences may explain, at least in part, the more favorable effects of inducers of HbF in SCD than in β-thalassemia. Further studies are necessary to fully understand the molecular bases of the different responses to agents that induce HbF in patients with these disorders.


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