Cytokine-mediated increases in fetal hemoglobin are associated with globin gene histone modification and transcription factor reprogramming.
Therapeutic regulation of globin genes is a primary goal of translational research aimed toward hemoglobinopathies. Signal transduction was used to identify chromatin modifications and transcription factor expression patterns that are associated with globin gene regulation. Histone modification and transcriptome profiling were performed using adult primary CD34(+) cells cultured with cytokine combinations that produced low versus high levels of gamma-globin mRNA and fetal hemoglobin (HbF). Embryonic, fetal, and adult globin transcript and protein expression patterns were determined for comparison. Chromatin immunoprecipitation assays revealed RNA polymerase II occupancy and histone tail modifications consistent with transcriptional activation only in the high-HbF culture condition. Transcriptome profiling studies demonstrated reproducible changes in expression of nuclear transcription factors associated with high HbF. Among the 13 genes that demonstrated differential transcript levels, 8 demonstrated nuclear protein expression levels that were significantly changed by cytokine signal transduction. Five of the 8 genes are recognized regulators of erythropoiesis or globin genes (MAFF, ID2, HHEX, SOX6, and EGR1). Thus, cytokine-mediated signal transduction in adult erythroid cells causes significant changes in the pattern of globin gene and protein expression that are associated with distinct histone modifications as well as nuclear reprogramming of erythroid transcription factors.
Sripichai
Orapan
O
Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Kiefer
Christine M
CM
Bhanu
Natarajan V
NV
Tanno
Toshihiko
T
Noh
Seung-Jae
SJ
Goh
Sung-Ho
SH
Russell
J Eric
JE
Rognerud
Cheryl L
CL
Ou
Ching-Nan
CN
Oneal
Patricia A
PA
Meier
Emily R
ER
Gantt
Nicole M
NM
Byrnes
Colleen
C
Lee
Y Terry
YT
Dean
Ann
A
Miller
Jeffery L
JL
D000328:Adult; D018952:Antigens, CD34; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D041905:Erythroid Cells / Q000166:cytology / Q000378:metabolism*; D005319:Fetal Hemoglobin / Q000096:biosynthesis*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006453:Hemoglobinopathies / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D006801:Humans; D011499:Protein Processing, Post-Translational; D012319:RNA Polymerase II / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D018952:Antigens, CD34; D016207:Cytokines; D006657:Histones; D014157:Transcription Factors; D005319:Fetal Hemoglobin; D012319:RNA Polymerase II