Lysine-Specific Histone Demethylase 1 Inhibition Enhances Robust Fetal Hemoglobin Induction in Human β0-Thalassemia/Hemoglobin E Rrythroid Cells

Abstract

Induction of fetal hemoglobin (HbF) ameliorates the clinical severity of β-thalassemias. Histone methyltransferase LSD1 enzyme removes methyl groups from the activating chromatin mark histone 3 lysine 4 at silenced genes, including the γ-globin genes. LSD1 inhibitor RN-1 induces HbF levels in cultured human erythroid cells. Here, the HbF-inducing activity of RN-1 was investigated in erythroid progenitor cells derived from β0-thalassemia/HbE patients. The significant and reproducible increases in γ-globin transcript and HbF expression upon RN-1 treatment was demonstrated in erythroid cells with divergent HbF baseline levels, the average of HbF induction was 17.7 + 0.8%. RN-1 at low concentration did not affect viability and proliferation of erythroid cells, but decreases in cell number was observed in cells treated with RN-1 at high concentration. Delayed terminal erythroid differentiation was revealed in β0-thalassemia/HbE erythroid cells treated with RN-1 as similar to other compounds that target LSD1 activity. Downregulation of repressors of γ-globin expression; NCOR1 and SOX6, was observed in RN-1 treatment. These findings provide a proof of concept that a LSD1 epigenetic enzymes is a potential therapeutic target for β0-thalassemia/HbE patients.

Pharmacological Induction of Fetal Hemoglobin in β-Thalassemia and Sickle Cell Disease: An Updated Perspective

“…At a concentration of 0.004 uM, RN-1 significantly increased the expression of γ-globin mRNA and HbF expression without any significant toxicity and regardless of HbF baseline levels [113]. Transcript levels of numerous key γ-globin repressors and co-repressors such as NCOR1, SOX6 and MYB were also modulated by RN-1 treatment [113]. Collectively, these data suggest the consideration of RN-1 for further development as an additional strategy to induce HbF in both SCD and thalassemic syndromes.…”

“…When tranylcypromine (TCP) and RN-1 were tested in primate and murine erythroid cell cultures, RN-1 was shown to induce F cells and γ-globin mRNA at much greater levels than either TCP or HU [112]. More recently, the use of RN-1 was investigated in erythroid progenitor cells derived from β0-thalassemia/HbE patients [113]. At a concentration of 0.004 uM, RN-1 significantly increased the expression of γ-globin mRNA and HbF expression without any significant toxicity and regardless of HbF baseline levels [113].…”

“…More recently, the use of RN-1 was investigated in erythroid progenitor cells derived from β0-thalassemia/HbE patients [113]. At a concentration of 0.004 uM, RN-1 significantly increased the expression of γ-globin mRNA and HbF expression without any significant toxicity and regardless of HbF baseline levels [113]. Transcript levels of numerous key γ-globin repressors and co-repressors such as NCOR1, SOX6 and MYB were also modulated by RN-1 treatment [113].…”

Effect of the LSD1 Inhibitor RN-1 on γ-globin and Global Gene Expression during Erythroid Differentiation in Baboons (Papio anubis)

“…Various pharmacological inhibitors targeting HDACs, DNMT1, LSD1, and G9A increase -globin expression in different experimental model systems and some of have advanced to clinical trials [12][13][14]. LSD1 inhibitors are particularly potent HbF activators and promising therapeutic agents as shown by studies in primary erythroid cell cultures derived from normal [15] and  o -thalassemia/HbE patients [16], sickle cell disease mouse models [17][18][19] and baboons [20][21][22], but detailed knowledge of their mechanism of action has not been established. Our previous studies showed that the LSD1 inhibitor RN-1 administration stimulated impressive increases in HbF levels [20] and was generally well-tolerated during a prolonged treatment period in baboons.…”

Metabolomics Study of Serum Samples of β-YAC Transgenic Mice Treated with Tenofovir Disoproxil Fumarate

“…One of the strategies to treat this disease is to reactivate the γ-globin gene that is already present in humans but is silenced during infant development (6–8 months’ birth age). As a result of γ-globin gene activation, the body starts to produce fetal hemoglobin which somehow reduces the blood deficiency in the body [ 3 , 4 ]. Different pharmacological agents have been tested at various stages of clinical trials for their ability to produce fetal hemoglobin [ 5 ].…”