scholarly journals Potential role of LSD1 inhibitors in the treatment of sickle cell disease: a review of preclinical animal model data

2018 ◽  
Vol 315 (4) ◽  
pp. R840-R847 ◽  
Author(s):  
Angela Rivers ◽  
Ramasamy Jagadeeswaran ◽  
Donald Lavelle

Sickle cell disease (SCD) is caused by a mutation of the β-globin gene (Ingram VM. Nature 180: 326–328, 1957), which triggers the polymerization of deoxygenated sickle hemoglobin (HbS). Approximately 100,000 SCD patients in the United States and millions worldwide (Piel FB, et al. PLoS Med 10: e1001484, 2013) suffer from chronic hemolytic anemia, painful crises, multisystem organ damage, and reduced life expectancy (Rees DC, et al. Lancet 376: 2018–2031, 2010; Serjeant GR. Cold Spring Harb Perspect Med 3: a011783, 2013). Hematopoietic stem cell transplantation can be curative, but the majority of patients do not have a suitable donor (Talano JA, Cairo MS. Eur J Haematol 94: 391–399, 2015). Advanced gene-editing technologies also offer the possibility of a cure (Goodman MA, Malik P. Ther Adv Hematol 7: 302–315, 2016; Lettre G, Bauer DE. Lancet 387: 2554–2564, 2016), but the likelihood that these strategies can be mobilized to treat the large numbers of patients residing in developing countries is remote. A pharmacological treatment to increase fetal hemoglobin (HbF) as a therapy for SCD has been a long-sought goal, because increased levels of HbF (α2γ2) inhibit the polymerization of HbS (Poillin WN, et al. Proc Natl Acad Sci USA 90: 5039–5043, 1993; Sunshine HR, et al. J Mol Biol 133: 435–467, 1979) and are associated with reduced symptoms and increased lifespan of SCD patients (Platt OS, et al. N Engl J Med 330: 1639–1644, 1994; Platt OS, et al. N Engl J Med 325: 11–16, 1991). Only two drugs, hydroxyurea and l-glutamine, are approved by the US Food and Drug Administration for treatment of SCD. Hydroxyurea is ineffective at HbF induction in ~50% of patients (Charache S, et al. N Engl J Med 332: 1317–1322, 1995). While polymerization of HbS has been traditionally considered the driving force in the hemolysis of SCD, the excessive reactive oxygen species generated from red blood cells, with further amplification by intravascular hemolysis, also are a major contributor to SCD pathology. This review highlights a new class of drugs, lysine-specific demethylase (LSD1) inhibitors, that induce HbF and reduce reactive oxygen species.

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4147-4147 ◽  
Author(s):  
Sruti Shiva ◽  
Enrico M Novelli ◽  
Grant C Bullock ◽  
Elizabeth Kenny ◽  
Gabrielle Hill ◽  
...  

Abstract It has long been recognized that platelets contain functional mitochondria and accumulating data suggest that several aspects of mitochondrial function, including reactive oxygen species production, modulate platelet thrombotic function. We have recently shown that platelet mitochondria isolated from patients with Sickle Cell Disease generate significantly greater concentrations of reactive oxygen species than healthy African American subjects and that this mitochondrial oxidant generation contributes to higher levels of basal platelet activation in these patients (Blood. 2014 May 1;123(18):2864-72). Based on these data, we have now investigated the factors that regulate platelet mitochondrial superoxide generation in healthy and Sickle Cell Disease platelets. Here we demonstrate that human platelets express mitochondrial uncoupling protein-2 (UCP2), a protein that is known to decrease the efficiency of oxidative phosphorylation and oxidant generation in other cell types but has previously not been identified in platelets. In this study we show that UCP2 protein is expressed in healthy human platelets and is fully functional as it facilitates proton leak across the inner mitochondrial membrane, leading to decreased mitochondrial membrane potential. Further, we demonstrate that the expression of this protein attenuates platelet mitochondrial superoxide generation, as treatment of platelets with Genipin (2-10µM), a pharmacological inhibitor of UCPs, concentration-dependently increases mitochondrial membrane potential and reactive oxygen species production. Further, an approximately 70% inhibition of UCP activity results in platelet activation demonstrated by increased membrane p-selectin expression (65±7% versus 6±3% in untreated controls) and augmented glycoprotein IIb/IIIa activation (57±9% versus 9±4% in untreated controls). The use of the mitochondrial-targeted antioxidant mitoTEMPO (10µM) decreases genipin-induced superoxide generation and significantly attenuates platelet activation. Notably, preliminary data presented here also suggest that UCP expression is decreased in platelets isolated from Sickle Cell Disease patients (3-fold) compared to healthy African American subjects. Additionally, ongoing studies are investigating platelet function in mice deficient in UCP2. Taken together, these data demonstrate a novel mechanism of regulation of platelet thrombotic function whose physiological relevance is apparent in the context of Sickle Cell Disease. More broadly this study advances the understanding of the role of the mitochondrion in platelet biology and thrombotic disease. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2019-2019
Author(s):  
Jagadeesh Ramasamy ◽  
Vinzon Ibanez ◽  
Vijaya Lakshmi Yalagala ◽  
Yogenthiran Saunthararajah ◽  
Robert E. Molokie ◽  
...  

Abstract The polymerization of deoxygenated HbS molecules in the red blood cells (RBCs) of patients with sickle cell disease (SCD) causes RBC destruction resulting in chronic pain, debilitating acute pain crises, strokes, multi-organ damage and a reduced life span. Therapeutic options remain limited. Bone marrow transplantation can be curative but is not an option for the majority of patients. Gene therapy interventions that also offer the promise of a cure are under investigation but are not likely to be available to the vast majority of patients in the near future. Hydroxyurea, the first drug approved for treatment of SCD, increases levels of Fetal Hemoglobin (HbF) that inhibit polymerization of HbS molecules but is not effective in all patients while a more powerful HbF-inducing drug, the DNA methyltransferase inhibitor decitabine has yet to be approved. L-glutamine, another approved therapeutic option, increases NAD redox potential and decreases reactive oxygen species (ROS) in the sickle RBCs to reduce symptoms. In our laboratory we have observed that increased ROS is associated with the retention of mitochondria in the SCD RBCs and have hypothesized that the abnormal presence of mitochondria in these cells is a major source of ROS (Jagadeeswaran et al Exp Hematol 50:46-52, 2017). In this investigation we have tested the hypothesis that chronic oral supplementation with nicotinamide, a direct precursor of NAD synthesis, would improve NAD redox potential, decrease mitochondrial retention and ROS in SCD RBCs, and reduce anemia in the SCD mouse model. The effect of nicotinamide was tested in SCD mice whose drinking water was supplemented for three months with 1% nicotinamide. The percentage of RBCs retaining mitochondria and the levels of ROS were determined by flow cytometric assays using the mitochondrial-specific dye TMRM and the ROS probe CM-H2DCFDA, respectively. In SCD mice receiving nicotinamide the fraction of RBCs retaining mitochondria was reduced 22.1% (p<0.05) and the level of ROS in RBCs was reduced 41% (p<0.01) compared to control SCD mice. The reticulocyte percentage was reduced 28% in nicotinamide-treated SCD mice compared to control SCD mice (p<0.01). The total RBC count was 30% higher (p<0.05) in nicotinamide-treated mice (6.61±0.76 X 10 6/μl) compared to control SCD mice (5.08±0.70 X 10 6/μl). Similar differences in hematocrit and total hemoglobin were also observed but failed to reach statistical significance. Total NAD levels were not significantly different in SCD mice receiving nicotinamide compared to control SCD mice (p<0.05), but the NADH/NAD total ratio was increased 2 fold (p<0.05). These results show that oral administration of high doses of nicotinamide decreases mitochondrial retention and ROS in SCD RBCs and improves NAD redox potential and anemia in SCD mice. These effects strongly suggest that additional studies be performed to investigate nicotinamide as a therapeutic option in SCD. Figure 1 Figure 1. Disclosures Saunthararajah: EpiDestiny: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.


2015 ◽  
Vol 173 (2) ◽  
pp. 386-395 ◽  
Author(s):  
J Brett Heimlich ◽  
Joshua S Speed ◽  
Paul M O'Connor ◽  
Jennifer S Pollock ◽  
Tim M Townes ◽  
...  

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 592
Author(s):  
Parul Rai ◽  
Kenneth I. Ataga

Sickle cell disease (SCD) afflicts millions of people worldwide but is referred to as an orphan disease in the United States. Over the past several decades, there has been an increasing understanding of the pathophysiology of SCD and its complications. While most individuals with SCD in resource-rich countries survive into adulthood, the life expectancy of patients with SCD remains substantially shorter than for the general African-American population. SCD can be cured using hematopoietic stem cell transplantation and possibly gene therapy, but these treatment approaches are not available to most patients, the majority of whom reside in low- and middle-income countries. Until relatively recently, only one drug, hydroxyurea, was approved by the US Food and Drug Administration to ameliorate disease severity. Multiple other drugs (L-glutamine, crizanlizumab, and voxelotor) have recently been approved for the treatment of SCD, with several others at various stages of clinical testing. The availability of multiple agents to treat SCD raises questions related to the choice of appropriate drug therapy, combination of multiple agents, and affordability of recently approved products. The enthusiasm for new drug development provides opportunities to involve patients in low- and middle-income nations in the testing of potentially disease-modifying therapies and has the potential to contribute to capacity building in these environments. Demonstration that these agents, alone or in combination, can prevent or decrease end-organ damage would provide additional evidence for the role of drug therapies in improving outcomes in SCD.


Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 296
Author(s):  
Rosa Vona ◽  
Nadia Maria Sposi ◽  
Lorenza Mattia ◽  
Lucrezia Gambardella ◽  
Elisabetta Straface ◽  
...  

Sickle cell disease (SCD) is the most common hereditary disorder of hemoglobin (Hb), which affects approximately a million people worldwide. It is characterized by a single nucleotide substitution in the β-globin gene, leading to the production of abnormal sickle hemoglobin (HbS) with multi-system consequences. HbS polymerization is the primary event in SCD. Repeated polymerization and depolymerization of Hb causes oxidative stress that plays a key role in the pathophysiology of hemolysis, vessel occlusion and the following organ damage in sickle cell patients. For this reason, reactive oxidizing species and the (end)-products of their oxidative reactions have been proposed as markers of both tissue pro-oxidant status and disease severity. Although more studies are needed to clarify their role, antioxidant agents have been shown to be effective in reducing pathological consequences of the disease by preventing oxidative damage in SCD, i.e., by decreasing the oxidant formation or repairing the induced damage. An improved understanding of oxidative stress will lead to targeted antioxidant therapies that should prevent or delay the development of organ complications in this patient population.


2021 ◽  
Author(s):  
Moataz Dowaidar

Autologous transplantation of gene-modified HSCs might be used to treat Sickle Cell Disease (SCD) once and for all. Hematopoietic Stem Cell (HSC) gene therapy with lentiviral-globin gene addition was optimized by HSC collection, vector constructs, lentiviral transduction, and conditioning in the current gene therapy experiment for SCD, resulting in higher gene marking and phenotypic correction. Further advancements over the next decade should allow for a widely approved gene-addition therapy. Long-term engraftment is crucial for gene-corrected CD34+ HSCs, which might be addressed in the coming years, and gene repair of the SCD mutation in the-globin gene can be achieved in vitro using genome editing in CD34+ cells. Because of breakthroughs in efficacy, safety, and delivery strategies, in vivo gene addition and gene correction in BM HSCs is advancing. Overall, further research is needed, but HSC-targeted gene addition/gene editing therapy is a promising SCD therapy with curative potential that might be widely available soon.


2012 ◽  
Vol 48 (4) ◽  
pp. 659-665 ◽  
Author(s):  
Aline Emmer Ferreira Furman ◽  
Railson Henneberg ◽  
Priscila Bacarin Hermann ◽  
Maria Suely Soares Leonart ◽  
Aguinaldo José do Nascimento

Sickle cell disease promotes hemolytic anemia and occlusion of small blood vessels due to the presence of high concentrations of hemoglobin S, resulting in increased production of reactive oxygen species and decreased antioxidant defense capacity. The aim of this study was to evaluate the protective action of a standardized extract of Ginkgo biloba (EGb 761), selected due to its high content of flavonoids and terpenoids, in erythrocytes of patients with sickle cell anemia (HbSS, SS erythrocytes) subjected to oxidative stress using tert-butylhydroperoxide or 2,2-azobis-(amidinepropane)-dihydrochloride, in vitro. Hemolysis indexes, reduced glutathione, methemoglobin concentrations, lipid peroxidation, and intracellular reactive oxygen species were determined. SS erythrocytes displayed increased rates of oxidation of hemoglobin and membrane lipid peroxidation compared to normal erythrocytes (HbAA, AA erythrocytes), and the concentration of EGb 761 necessary to achieve the same antioxidant effect in SS erythrocytes was at least two times higher than in normal ones, inhibiting the formation of intracellular reactive oxygen species (IC50 of 13.6 µg/mL), partially preventing lipid peroxidation (IC50 of 242.5 µg/mL) and preventing hemolysis (IC50 of 10.5 µg/mL). Thus, EGb 761 has a beneficial effect on the oxidative status of SS erythrocytes. Moreover, EGb 761 failed to prevent oxidation of hemoglobin and reduced glutathione at the concentrations examined.


2016 ◽  
Vol 113 (38) ◽  
pp. 10661-10665 ◽  
Author(s):  
Lin Ye ◽  
Jiaming Wang ◽  
Yuting Tan ◽  
Ashley I. Beyer ◽  
Fei Xie ◽  
...  

Hereditary persistence of fetal hemoglobin (HPFH) is a condition in some individuals who have a high level of fetal hemoglobin throughout life. Individuals with compound heterozygous β-thalassemia or sickle cell disease (SCD) and HPFH have milder clinical manifestations. Using RNA-guided clustered regularly interspaced short palindromic repeats-associated Cas9 (CRISPR-Cas9) genome-editing technology, we deleted, in normal hematopoietic stem and progenitor cells (HSPCs), 13 kb of the β-globin locus to mimic the naturally occurring Sicilian HPFH mutation. The efficiency of targeting deletion reached 31% in cells with the delivery of both upstream and downstream breakpoint guide RNA (gRNA)-guided Staphylococcus aureus Cas9 nuclease (SaCas9). The erythroid colonies differentiated from HSPCs with HPFH deletion showed significantly higher γ-globin gene expression compared with the colonies without deletion. By T7 endonuclease 1 assay, we did not detect any off-target effects in the colonies with deletion. We propose that this strategy of using nonhomologous end joining (NHEJ) to modify the genome may provide an efficient approach toward the development of a safe autologous transplantation for patients with homozygous β-thalassemia and SCD.


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