scholarly journals Comparison of CD34 + cells isolated from frozen cord blood and fresh adult peripheral blood of sickle cell disease patients in gene correction of the sickle mutation at late‐stage erythroid differentiation

Author(s):  
Chutima Kumkhaek ◽  
Naoya Uchida ◽  
John F. Tisdale ◽  
Griffin P. Rodgers
Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 160-160
Author(s):  
Brian M. Dulmovits ◽  
Abena O. Appiah-Kubi ◽  
Julien Papoin ◽  
John Hale ◽  
Mingzhu He ◽  
...  

Abstract Pomalidomide, a second-generation immunomodulatory drug, is a fetal hemoglobin (HbF) inducing agent with potential implications for the treatment of β-hemoglobinopathies such as sickle cell disease (SCD). However, its mechanism of action remains unknown. Through an in-depth characterization of human erythropoiesis and globin gene regulatory networks, we now provide evidence that pomalidomide alters transcription networks involved in erythropoiesis and globin switching, thereby leading to a partial reprogramming of adult hematopoietic progenitors toward fetal-like erythropoiesis. Adult peripheral blood CD34+ cells from normal individuals were differentiated toward the red cell lineage using an adapted 3-phase culture system. At day 14 of culture, we observed a reciprocal globin gene switch at the mRNA and protein levels. These results were confirmed by high performance liquid chromatography of hemolysates (HbF/(HbF+HbA): 31.7 ± 1.4% vs. 6.5 ± 0.7% pomalidomide and vehicle, respectively). Next, we studied erythroid differentiation using flow cytometric analyses of the cell surface markers interleukin-3R (IL-3R), glycophorin A (GPA), CD34 and CD36 for early erythroid precursors (BFU-E and CFU-E) as well as GPA, α4-integrin and band3 for terminal erythroid differentiation. While there were no changes in terminal erythroblast maturation, an accumulation of BFU-E in pomalidomide-treated cultures at days 2 and 4 of differentiation was seen, indicating a delay at the BFU-E to CFU-E transition, and also, that pomalidomide exerts its effect in the early-stages of erythropoiesis. Indeed, treatment with pomalidomide during the phase of the culture system that generates erythroid progenitors led to significantly more γ-globin expression than treatment during the phase which proerythroblasts undergo terminal erythroid differentiation. At the molecular level, pomalidomide was found to rapidly and robustly decrease Ikaros (IKZF1) expression exclusively by post-translational targeting to the proteasome. Moreover, pomalidomide selectively reduced the expression of components of key globin regulatory pathways including BCL11A, SOX6, KLF1, GATA1 and LSD1 while not affecting others (e.g. CoREST, GATA2, GFI1B, and HDAC1). Pomalidomide had a transient effect on GATA1 and KLF1 expression. While shRNA knockdown of Ikaros using two different lentiviral constructs delayed erythroid differentiation, it failed to appreciably stimulate HbF production or alter BCL11A expression. These results suggest that the loss of Ikaros alone is insufficient to recapitulate the phenotype observed in pomalidomide-treated conditions. We next compared the expression levels of proteins involved in globin gene regulation among untreated peripheral blood, pomalidomide-treated peripheral blood and untreated cord blood-derived erythroid cells. We found striking similarities between cord blood and pomalidomide-treated adult cells at day 4 of differentiation. Indeed, BCL11A, KLF1, SOX6, LSD1 and GATA1 showed decreased expression levels both in cord blood and pomalidomide-treated adult peripheral blood, while the levels of CoREST, HDAC1 and GATA2 remained unchanged indicating that pomalidomide partially reprograms adult erythroid cells to a fetal-like state. Taken together, our results show that the mechanism underlying reactivation of HbF by pomalidomide involves Ikaros-independent reprogramming of adult erythroid progenitors. Finally, we found that this mechanism is conserved in SCD-derived CD34+ cells. Our work has broad implications for globin switching, as we provide direct evidence that Ikaros does not play a major role in the repression of γ-globin during adult erythropoiesis, and further supports the previously held notion that globin chain production is determined prior to or at the level of CFU-E. Disclosures Allen: Celgene: Research Funding; Bristol Myers Squibb: Equity Ownership; Onconova: Membership on an entity's Board of Directors or advisory committees; Alexion: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4703-4703 ◽  
Author(s):  
So Hyun Park ◽  
Ciaran M Lee ◽  
Harshavardhan Deshmukh ◽  
Gang Bao

Abstract Introduction Sickle cell disease (SCD) is one of the most common monogenic disorders, affecting millions worldwide. SCD is caused by a point mutation in the β-globin gene (HBB). A single nucleotide substitution from A to T in the codon for the sixth amino acid in the β-globin protein converts a glutamic acid to a valine that leads to the production of sickle hemoglobin (HbS), which impairs the function of the red blood cells (RBCs). Allogeneic hematopoietic stem cell transplantation (HSCT) is the only available cure, but it is feasible for only a small subpopulation (<15%) of patients and may be associated with a high risk. Here, we show that targeted genome editing can potentially provide a permanent cure for SCD by correcting the sickle mutation in clinically relevant hematopoietic stem and progenitor cells (HSPCs) for autologous transplantation. Methods For proof-of-concept, we designed CRISPR/Cas9 systems and donor templates to introduce the sickle mutation into wild-type (WT) HBB of mobilized peripheral blood CD34+ cells. To assess genome-editing outcomes mediated by CRISPR/Cas9 systems, we developed a novel digital droplet PCR (ddPCR) assay that can quantify the rates of non-homologous end joining (NHEJ) and homology directed repair (HDR) events simultaneously following the generation of DNA double strand breaks. The assay enables rapid and accurate quantification of gene modifications in HSPCs by CRISPR/Cas9 genome-editing. Specifically, Streptococcus pyogenes (Spy) Cas9 proteins, guide RNAs (gRNA), and single-stranded DNA (ssDNA) donor templates were delivered into CD34+ cells by nucleofection with optimized conditions. Different gRNAs targeting HBB near the SCD mutation site were tested, and the optimal gRNA was chosen based on high on-target activity and proximity to the mutation site. The optimal DNA donor design and concentration were determined based on the frequency of HDR events and viability/growth rate of edited cells. Treated samples and untreated controls were assayed as both single cell clones and in bulk culture. In 2-phase liquid culture, genome editing frequencies at both DNA and mRNA levels were quantified by ddPCR to confirm persistence of edited cells in the heterozygous population over time. The expression of globins and other erythroid markers were monitored using flow cytometry and real time PCR to determine if genome editing had any effect on the kinetics of erythropoiesis. Colony formation assays were used to determine the number and type of colonies following induction of differentiation. Colony ddPCR was performed to determine the genotype of edited cells. Wright/Giemsa stain was used to confirm terminal maturation of erythrocytes into enucleated RBC. Native polyacrylamide gel electrophoresis (PAGE) and high performance liquid chromatography (HPLC) were used to confirm translation of edited β-globin protein and formation of HbS. Results and Discussion We found that the efficiency of site-specific gene correction could be substantially improved by optimizing the CRISPR/Cas9 systems for genome editing. For example, with optimization, we achieved ~30% HDR rates in CD34+ cells with >80% cell viability. The HDR-modified alleles persisted in the population over the course of differentiation, and the edited CD34+ cells retained differentiation potential. Genotyping of individual erythroid colonies confirmed that up to 35% of colonies are either homozygous or heterozygous for HDR alleles. Following differentiation, treated cells express modified HBB mRNA and HbS. In addition, the off-target activity of the HBB-specific gRNAs was determined using both bioinformatics tools and unbiased genome-wide mapping techniques. Ongoing work includes the validation of gene correction in SCD patient derived HSPCs, characterization of modified cells in vitro and in vivo to assess the therapeutic potential, and analysis of long-term genotoxicity. Conclusions Based on the proof-of-concept study, we demonstrate that using the optimized CRISPR/Cas9 system and donor template, an HDR rate of ~30% can be achieved in CD34+ cells. The gene corrected cells have the potential to differentiate into erythroid cells that permanently produce WT β-globin. Our findings provide promising evidence for clinical translation of the HSPCs genome correction strategy in treating SCD patients, as well as correcting gene defects underlying other inherited single-gene disorders. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3200-3200
Author(s):  
Julie Jaffray ◽  
Jingping Hu ◽  
Jie Li ◽  
Xiuli An ◽  
Mohandas Narla

Abstract Abstract 3200 Purified CD34+ cells derived from either cord blood (CB) or peripheral blood (PB) are currently being used to further our molecular and mechanistic understanding of human terminal erythroid differentiation. What is unclear is whether there are differences in the kinetics of terminal erythroid differentiation of CD34+ cells from these two sources. In the present study, we document that terminal differentiation in cultured CD34+ cells purified from peripheral blood is faster than that of CD34+ cells from cord blood. For these studies, we optimized an 18 day, three phase, in vitro culture system using CD34+ cells to obtain enucleated reticulocytes. In this system, proerythroblasts are generated starting at day 6 which further differentiate during the duration of culture to eventually generate reticulocytes. Based on the expression of various membrane surface markers, we used flow cytometry to quantitatively monitor terminal erythroid differentiation from proerythroblasts to enucleated reticulocytes during culture. The three surface markers, alpha-4 integrin, band 3 and CD36 enabled us to clearly distinguish between all distinct stages of terminal erythroid differentiation – proerythroblasts, early- and late- basophilic erythroblasts, polychromatic and orthochromatic erythroblasts. These analyses enabled us to show that CD34+ cells purified and cultured from peripheral blood underwent terminal erythroid differentiation at a faster rate than CD34+ cells from cord blood. Terminal erythroid differentiation in cord blood cultures was delayed on an average of 2 to 3 days compared to peripheral blood. For example, the surface protein expression pattern seen on days 11–12 of cell culture of peripheral CD34+ cells was not achieved in cord blood cultures until day 14. This delay in terminal differentiation was also reflected by increased extents of enucleation in peripheral blood cultures compared to cord blood (culture day 12: 33% enucleation in PB and 7% in CB and on day 14: 45% enucleation in PB and 19% in CB). These findings have enabled us to document significant differences between the kinetics of terminal erythroid differentiation of CD34+ cells derived from fetal cord and adult peripheral blood. While at the present time we do not have a mechanistic understanding for this difference, we are currently exploring if the observed differences may be related to differences in cell cycle dynamics between fetal and adult erythropopiesis. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 30-31
Author(s):  
Kevin R. Gillinder ◽  
Casie Leigh Reed ◽  
Shezlie Malelang ◽  
Helen Lorraine Mitchell ◽  
Emma Hoskin ◽  
...  

Sickle cell disease (SCD) affects millions of people worldwide and represents the most common monogenic disease of mankind (1). It is due to a homozygous T to A transversion in the β-globin gene that results in an amino acid variant - G6V - and production of HbS, which polymerises in red blood cells (RBCs) under hypoxic conditions. This generates irreversibly sickled cells that fail to traverse the microcirculation, resulting in micro-infarcts, hypoxia and pain, or 'sickle cell crises'. During gestation RBCs utilise different sets of globin genes to produce embryonic and fetal hemoglobins (HbF), so it is not until after birth when adult hemoglobin (HbA) is first produced that the first signs of SCD become apparent. This process termed 'hemoglobin switching' has been the focus of research efforts for decades because it offers an opportunity to reactivate HbF in adult cells of patients with hemoglobinopathies. A number of transcription factors, including Krüppel-like factor 1 (KLF1), play critical roles in hemoglobin switching. KLF1 is an essential erythroid transcription factor that co-ordinates the expression of more than a thousand genes critical to the formation of adult RBCs. KLF1 directly binds the β-globin gene promoter to up regulate its expression, whilst regulating the expression of additional factors like BCL11A and LRF that directly repress γ-globin expression (HbF). Heterozygosity for loss of function mutations in KLF1 leads to a significant increase in HbF that is beneficial to patients with β-thalassemia. We propose this can be recreated by advanced gene editing techniques to provide an effective therapy for SCD. We have employed CRISPR-based gene editing to knockout the expression of KLF1 in human cells. We designed two separate sgRNAs with corresponding HDR templates to target the second exon of KLF1 and ablate its function. We optimised transfection protocols and tested the on-target specificity of our sgRNAs achieving &gt;90% efficacy in all cell types assayed. Using HUDEP-2 cells (2), a conditionally immortalised erythroid cell line which harbors three copies of KLF1 (3), we have demonstrated that these cells require at least one copy (&gt;1/3) for survival; heterozygous cells (+/-/- or +/+/-) proliferate at a reduced rate, but are able to differentiate normally. Using RNA-seq, we identified some genes, including ICAM-4 and BCAM, which are down-regulated accordingly in a KLF1 gene dosage-dependent manner. ICAM-4 and BCAM are cellular adhesion molecules implicated in triggering vaso-occlusive episodes (4; 5), so it is anticipated their reduced expression may provide additional benefit in treating SCD. Gamma-globin is upregulated 10-fold, BCL11A down-regulated 3-fold, and HbF+ RBCs generated at ~20% of total RBCs in KLF1 +/-/- HUDEP-2 cell lines. We also engineered the ablation of KLF1 in CD34+ cells harvested from the peripheral blood of SCD patients undergoing exchange transfusions. Following transfection of the two guides, we performed directed differentiation using an erythroid differentiation medium and analysed the levels of HbF. We observed HbF at levels of between 40-60% of total Hb by HPLC, and HbF+ cells of ~50% by FACS. There was no measurable block in erythroid differentiation by FACS. We documented the types of gene editing using a high throughout NGS assay (6). We compared efficiencies of CRISPR repair of the HbS mutation with CRIPSR damage of the KLF1 gene. Lastly, we transplanted gene-edited CD34 cells into NSGW41 mice (where human erythropoiesis is established) to determine the efficiency and safety of editing long term HSCs from SCD patients. We will report on the results of these xenotransplantation assays. Taken together these results reveal the potential utility in targeting KLF1 to cure SCD. References: Wastnedge, E. et al..J Glob Health 8, 021103 (2018). Kurita, R. et al.PLoS One 8, e59890 (2013). Vinjamur, D. S. & Bauer, D. E. Methods Mol Biol 1698, 275-284 (2018). Bartolucci, P. et al..Blood 116, 2152-9 (2010). Zhang, J., et al. PLoS One 14, e0216467 (2019). Bell, C. C., et al. BMC Genomics 15, 1002 (2014). Perkins, A. et al..Blood 127, 1856-62 (2016). Disclosures Kaplan: Celgene: Honoraria; Novartis: Honoraria. Perkins:Novartis Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees.


2001 ◽  
Vol 20 (2) ◽  
pp. 167-174 ◽  
Author(s):  
William Reed ◽  
Mark Walters ◽  
Elizabeth Trachtenberg ◽  
Renee Smith ◽  
Bertram Lubin

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 29-30
Author(s):  
Yuanbin Song ◽  
Rana Gbyli ◽  
Liang Shan ◽  
Wei Liu ◽  
Yimeng Gao ◽  
...  

In vivo models of human erythropoiesis with generation of circulating mature human red blood cells (huRBC) have remained elusive, limiting studies of primary human red cell disorders. In our prior study, we have generated the first combined cytokine-liver humanized immunodeficient mouse model (huHepMISTRG-Fah) with fully mature, circulating huRBC when engrafted with human CD34+ hematopoietic stem and progenitor cells (HSPCs)1. Here we present for the first time a humanized mouse model of human sickle cell disease (SCD) which replicates the hallmark pathophysiologic finding of vaso-occlusion in mice engrafted with primary patient-derived SCD HSPCs. SCD is an inherited blood disorder caused by a single point mutation in the beta-globin gene. Murine models of SCD exclusively express human globins in mouse red blood cells in the background of murine globin knockouts2 which exclusively contain murine erythropoiesis and red cells and thus fail to capture the heterogeneity encountered in patients. To determine whether enhanced erythropoiesis and most importantly circulating huRBC in engrafted huHepMISTRG-Fah mice would be sufficient to replicate the pathophysiology of SCD, we engrafted it with adult SCD BM CD34+ cells as well as age-matched control BM CD34+ cells. Overall huCD45+ and erythroid engraftment in BM (Fig. a, b) and PB (Fig. c, d) were similar between control or SCD. Using multispectral imaging flow cytometry, we observed sickling huRBCs (7-11 sickling huRBCs/ 100 huRBCs) in the PB of SCD (Fig. e) but not in control CD34+ (Fig. f) engrafted mice. To determine whether circulating huRBC would result in vaso-occlusion and associated findings in SCD engrafted huHepMISTRG-Fah mice, we evaluated histological sections of lung, liver, spleen, and kidney from control and SCD CD34+ engrafted mice. SCD CD34+ engrafted mice lungs showed an increase in alveolar macrophages (arrowheads) associated with alveolar hemorrhage and thrombosis (arrows) but not observed control engrafted mice (Fig. g). Spleens of SCD engrafted mice showed erythroid precursor expansion, sickled erythrocytes in the sinusoids (arrowheads), and vascular occlusion and thrombosis (arrows) (Fig. h). Liver architecture was disrupted in SCD engrafted mice with RBCs in sinusoids and microvascular thromboses (Fig. i). Congestion of capillary loops and peritubular capillaries and glomeruli engorged with sickled RBCs was evident in kidneys (Fig. j) of SCD but not control CD34+ engrafted mice. SCD is characterized by ineffective erythropoiesis due to structural abnormalities in erythroid precursors3. As a functional structural unit, erythroblastic islands (EBIs) represent a specialized niche for erythropoiesis, where a central macrophage is surrounded by developing erythroblasts of varying differentiation states4. In our study, both SCD (Fig. k) and control (Fig. l) CD34+ engrafted mice exhibited EBIs with huCD169+ huCD14+ central macrophages surrounded by varying stages of huCD235a+ erythroid progenitors, including enucleated huRBCs (arrows). This implies that huHepMISTRG-Fah mice have the capability to generate human EBIs in vivo and thus represent a valuable tool to not only study the effects of mature RBC but also to elucidate mechanisms of ineffective erythropoiesis in SCD and other red cell disorders. In conclusion, we successfully engrafted adult SCD patient BM derived CD34+ cells in huHepMISTRG-Fah mice and detected circulating, sickling huRBCs in the mouse PB. We observed pathological changes in the lung, spleen, liver and kidney, which are comparable to what is seen in the established SCD mouse models and in patients. In addition, huHepMISTRG-Fah mice offer the opportunity to study the role of the central macrophage in human erythropoiesis in health and disease in an immunologically advantageous context. This novel mouse model could therefore serve to open novel avenues for therapeutic advances in SCD. Reference 1. Song Y, Shan L, Gybli R, et. al. In Vivo reconstruction of Human Erythropoiesis with Circulating Mature Human RBCs in Humanized Liver Mistrg Mice. Blood. 2019;134:338. 2. Ryan TM, Ciavatta DJ, Townes TM. Knockout-transgenic mouse model of sickle cell disease. Science. 1997;278(5339):873-876. 3. Blouin MJ, De Paepe ME, Trudel M. Altered hematopoiesis in murine sickle cell disease. Blood. 1999;94(4):1451-1459. 4. Manwani D, Bieker JJ. The erythroblastic island. Curr Top Dev Biol. 2008;82:23-53. Disclosures Xu: Seattle Genetics: Membership on an entity's Board of Directors or advisory committees. Flavell:Zai labs: Consultancy; GSK: Consultancy.


Data in Brief ◽  
2017 ◽  
Vol 10 ◽  
pp. 192-197 ◽  
Author(s):  
Iakovos Armenis ◽  
Vassiliki Kalotychou ◽  
Revekka Tzanetea ◽  
Panagoula Kollia ◽  
Zoi Kontogeorgiou ◽  
...  

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