Abstract
Therapeutic intervention aimed at reactivation of fetal hemoglobin protein (HbF) is a promising approach for ameliorating sickle cell disease (SCD) and β-thalassemia. Previous studies showed genetic knockdown of histone deacetylase (HDAC) 1 or 2 is sufficient to induce HbF. Here we show that ACY-957, a selective chemical inhibitor of HDAC1 and 2 (HDAC1/2), elicits a dose and time dependent induction of γ-globin mRNA (HBG) and HbF in cultured primary cells derived from healthy individuals and sickle cell patients. Gene expression profiling of erythroid progenitors treated with ACY-957 identified global changes in gene expression that were significantly enriched in genes previously shown to be affected by HDAC1 or 2 knockdown. These genes included GATA2, which was induced greater than 3-fold. Lentiviral overexpression of GATA2 in primary erythroid progenitors increased HBG, and reduced adult β-globin mRNA (HBB). Furthermore, knockdown of GATA2 attenuated HBG induction by ACY-957. Chromatin immunoprecipitation and sequencing (ChIP-Seq) of primary erythroid progenitors demonstrated that HDAC1 and 2 occupancy was highly correlated throughout the GATA2 locus and that HDAC1/2 inhibition led to elevated histone acetylation at well-known GATA2 autoregulatory regions. The GATA2 protein itself also showed increased binding at these regions in response to ACY-957 treatment. These data show that chemical inhibition of HDAC1/2 induces HBG and suggest that this effect is mediated, at least in part, by histone acetylation-induced activation of the GATA2 gene.
Highlights
sickle cell disease (SCD) and β-thalassemia are recessive hemoglobinopathies that affect the β-globin subunit of adult hemoglobin
We synthesized a library of these HDAC1/2-selective compounds, from which ACY957 (Fig 1A) was chosen for further study based on its histone deacetylase (HDAC) selectivity profile, described in more detail below, and for its favorable pharmacokinetic properties in mouse, rat, dog, and monkey [36]
Observed elevated GATA2 expression in primary cells derived from SCD patients following 3 days of culture with 1 μM ACY-957 (Fig 5G). These results suggest that inhibition of HDAC1/2 prevents the suppression of GATA2 gene expression during the early stages of erythroid maturation, and raised the possibility that GATA2 may act as an HBG activator
Summary
SCD and β-thalassemia are recessive hemoglobinopathies that affect the β-globin subunit of adult hemoglobin. They are among the most common genetic disorders in the world [1]. In SCD, a single amino acid substitution leads to formation of hemoglobin with lowered solubility when deoxygenated (HbS) [2]. HbS aggregation leads to distortion of the red blood cell into a rigid, sickle-like shape. These cells undergo premature lysis, resulting in chronic anemia, and block small blood vessels, reducing oxygen delivery to tissues. In β-thalassemia, a PLOS ONE | DOI:10.1371/journal.pone.0153767. In β-thalassemia, a PLOS ONE | DOI:10.1371/journal.pone.0153767 April 13, 2016
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
