5-Azacytidine stimulates fetal hemoglobin synthesis in anemic baboons.

DeSimone, Joseph; Heller, Paul; Hall, Lemuel; Zwiers, D

doi:10.1073/pnas.79.14.4428

Cited by 346 publications

(175 citation statements)

References 21 publications

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“…1). DNA methylation plays an important role in globin gene expression, and DNA demethylating agents have been shown to induce HbF expression in various model systems and patients (8,17,18). However, the role of the methyltransferase DNMT1 in γ-globin silencing in an intact animal has not been previously assessed by formal genetic experiments.…”

Section: Depletion Of Lsd1 Induces Hbf Expression and Impairs Erythromentioning

confidence: 99%

Corepressor-dependent silencing of fetal hemoglobin expression by BCL11A

Bauer

Kerényi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

203

188

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Reactivation of fetal hemoglobin (HbF) in adults ameliorates the severity of the common β-globin disorders. The transcription factor BCL11A is a critical modulator of hemoglobin switching and HbF silencing, yet the molecular mechanism through which BCL11A coordinates the developmental switch is incompletely understood. Particularly, the identities of BCL11A cooperating protein complexes and their roles in HbF expression and erythroid development remain largely unknown. Here we determine the interacting partner proteins of BCL11A in erythroid cells by a proteomic screen. BCL11A is found within multiprotein complexes consisting of erythroid transcription factors, transcriptional corepressors, and chromatinmodifying enzymes. We show that the lysine-specific demethylase 1 and repressor element-1 silencing transcription factor corepressor 1 (LSD1/CoREST) histone demethylase complex interacts with BCL11A and is required for full developmental silencing of mouse embryonic β-like globin genes and human γ-globin genes in adult erythroid cells in vivo. In addition, LSD1 is essential for normal erythroid development. Furthermore, the DNA methyltransferase 1 (DNMT1) is identified as a BCL11A-associated protein in the proteomic screen. DNMT1 is required to maintain HbF silencing in primary human adult erythroid cells. DNMT1 haploinsufficiency combined with BCL11A deficiency further enhances γ-globin expression in adult animals. Our findings provide important insights into the mechanistic roles of BCL11A in HbF silencing and clues for therapeutic targeting of BCL11A in β-hemoglobinopathies.gene regulation | globin switching | hematopoiesis

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Section: Depletion Of Lsd1 Induces Hbf Expression and Impairs Erythromentioning

confidence: 99%

Corepressor-dependent silencing of fetal hemoglobin expression by BCL11A

Bauer

Kerényi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

203

188

View full text Add to dashboard Cite

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“…In addition, a variety of studies in cell culture systems have shown that 5-azacytidine, a cytotoxic pyrimidine analog that inhibits DNA methylation, can induce cellular differentiation (15) and either directly activate (16) or allow activation of specific genes (17). More recently it has been demonstrated that 5-azacytidine causes selectively increased expression concomitant with specific demethylation of the fetal y-globin genes in anemic baboons (18) as well as human patients with f-thalassemia (19) or sickle cell anemia (20). In these latter studies there remains some question as to whether increased t-globin gene expression is due to gene demethylation, cell selection, or both, since 5-azacytidine is known to have a variety of toxic effects on cells, and since y-globin expression can be stimulated in adults by several types of bone marrow stress.…”

mentioning

confidence: 99%

Activation of a chicken embryonic globin gene in adult erythroid cells by 5-azacytidine and sodium butyrate.

Ginder¹,

Whitters²,

Pohlman³

1984

Proc. Natl. Acad. Sci. U.S.A.

126

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Adult White Leghorn chickens were rendered anemic by injection with 1-acetyl-2-phenylhydrazine and then treated with parenteral 5-azacytidine, and levels of embryonic globin RNA in circulating reticulocytes were measured. A very small but detectable amount of correctly initiated embryonic p-type globin RNA was detected in reticulocytes from birds treated with 5-azacytidine, while none was detected in reticulocytes from those receiving only phenylhydrazine or phenylhydrazine plus 1-f3-D-arabinofuranosylcytosine (cytosine arabinonucleoside). An attempt to increase embryonic globin RNA induction by treatment with parenteral sodium butyrate after 7 days of 5-azacytidine administration resulted in a 5-to 10-fold increase in the level of embryonic globin RNA. However, sodium butyrate did not induce embryonic gene expression when given alone or after treatment with cytosine arabinonucleoside. Sodium butyrate treatment also caused a DNase I-hypersensitive site to be exposed at the 5' end of the p-globin gene only after 5-azacytidine induced demethylation of several CpG sites in and around the gene. (20). In these latter studies there remains some question as to whether increased t-globin gene expression is due to gene demethylation, cell selection, or both, since 5-azacytidine is known to have a variety of toxic effects on cells, and since y-globin expression can be stimulated in adults by several types of bone marrow stress.As part of ongoing studies aimed at elucidating mechanisms that regulate globin gene expression, we have attempted to study the effects of demethylation of embryonic globin genes in anemic adult chickens. We report here that while 5-azacytidine treatment causes nearly complete demethylation of the p embryonic globin gene in adult erythroid cells, only a minimal amount of p-globin RNA is detectable, and the surrounding chromatin structure, as assayed by DNase I digestion, does not differ from untreated controls. On the other hand, pharmacologic doses of sodium butyrate greatly increase the amount of embryonic p-globin RNA in adult reticulocytes and result in the exposure of a 5' DNase I-hypersensitive site in some of the reticulocyte nuclei, but only when the gene has first become demethylated by 5-azacytidine treatment. MATERIALS AND METHODS Treatment of Animals and Blood Collection. Adult WhiteLeghorn hens (Yoder, Kalona, IA) were rendered anemic by five daily intramuscular injections with 1-acetyl-2-phenylhydrazine (Sigma) at 20 mg/kg or by phlebotomy of 10 ml of whole blood per day to achieve a hematocrit of 18-22% (normal 35-40%). Reticulocyte 3954The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

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“…The capacity of 5-azacytidine to stimulate HbF synthesis in vivo was demonstrated in 1982 in an anemic baboon [96]. These observations stimulated the development of clinical trials of 5-azacytidine in a small number of sickle cell anemia and β-thalassemia patients.…”

Section: Chemical Inducers Of Hbf Synthesismentioning

confidence: 98%

“…This compensatory erythroid response is characterized by the presence of an increased proportion of erythroid elements synthesizing HbF [90]. The second hypothesis is based on the capacity of 5-Aza to inhibit DNA methyltransferase enzymes, resulting in inhibition of DNA methylation [91]: It was supposed that demethylation of DNA in the promoter region of fetal globin genes leads to a transcriptional derepression of these genes [92,93].…”

Section: Chemical Inducers Of Hbf Synthesismentioning

confidence: 99%