Identification of HIF2alpha as an important STAT5 target gene in human hematopoietic stem cells.
The transcription factor signal transducer and activator of transcription 5 (STAT5) fulfills essential roles in self-renewal in mouse and human hematopoietic stem cells (HSCs), and its persistent activation contributes to leukemic transformation, although little molecular insight into the underlying mechanisms has been obtained. In the present study, we show that STAT5 can impose long-term expansion exclusively on human HSCs, not on progenitors. This was associated with an enhanced cobblestone formation under bone marrow stromal cells of STAT5-transduced HSCs. Hypoxia-induced factor 2α (HIF2α) was identified as a STAT5 target gene in HSCs, and chromatin immunoprecipitation studies revealed STAT5 binding to a site 344 base pairs upstream of the start codon of HIF2α. Lentiviral RNA interference (RNAi)-mediated down-modulation of HIF2α impaired STAT5-induced long-term expansion and HSC frequencies, whereas differentiation was not affected. Glucose uptake was elevated in STAT5-activated HSCs, and several genes associated with glucose metabolism were up-regulated by STAT5 in an HIF2α-dependent manner. Our studies indicate that pathways normally activated under hypoxia might be used by STAT5 under higher oxygen conditions to maintain and/or impose HSC self-renewal properties.
Department of Hematology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
Szabolcs
S
Fatrai
Albertus T J
AT
Wierenga
Simon M G J
SM
Daenen
Edo
E
Vellenga
Jan Jacob
JJ
Schuringa
D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D015687:Cell Hypoxia / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D008954:Models, Biological; D023461:Myeloid Progenitor Cells / Q000378:metabolism / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology; D011247:Pregnancy; D050799:STAT5 Transcription Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000099162:Endothelial PAS Domain-Containing Protein 1
D051792:Basic Helix-Loop-Helix Proteins; D005947:Glucose; D010100:Oxygen; D050799:STAT5 Transcription Factor; D000099162:Endothelial PAS Domain-Containing Protein 1