Increased levels of NOTCH1, NF-kappaB, and other interconnected transcription factors characterize primitive sets of hematopoietic stem cells.
As previously shown, higher levels of NOTCH1 and increased NF-kappaB signaling is a distinctive feature of the more primitive umbilical cord blood (UCB) CD34+ hematopoietic stem cells (HSCs), as compared to bone marrow (BM). Differences between BM and UCB cell composition also account for this finding. The CD133 marker defines a more primitive cell subset among CD34+ HSC with a proposed hemangioblast potential. To further evaluate the molecular basis related to the more primitive characteristics of UCB and CD133+ HSC, immunomagnetically purified human CD34+ and CD133+ cells from BM and UCB were used on gene expression microarrays studies. UCB CD34+ cells contained a significantly higher proportion of CD133+ cells than BM (70% and 40%, respectively). Cluster analysis showed that BM CD133+ cells grouped with the UCB cells (CD133+ and CD34+) rather than to BM CD34+ cells. Compared with CD34+ cells, CD133+ had a higher expression of many transcription factors (TFs). Promoter analysis on all these TF genes revealed a significantly higher frequency (than expected by chance) of NF-kappaB-binding sites (BS), including potentially novel NF-kappaB targets such as RUNX1, GATA3, and USF1. Selected transcripts of TF related to primitive hematopoiesis and self-renewal, such as RUNX1, GATA3, USF1, TAL1, HOXA9, HOXB4, NOTCH1, RELB, and NFKB2 were evaluated by real-time PCR and were all significantly positively correlated. Taken together, our data indicate the existence of an interconnected transcriptional network characterized by higher levels of NOTCH1, NF-kappaB, and other important TFs on more primitive HSC sets.
Panepucci
Rodrigo Alexandre
RA
Department of Clinical Medicine of the Faculty of Medicine of Ribeirao Preto-USP, Center for Cell Therapy and Regional Blood Center, Araraquara, São Paulo, Brazil. rapane@gmail.com
Oliveira
Lucila Habib B
LH
Zanette
Dalila Luciola
DL
Viu Carrara
Rita de Cassia
Rde C
Araujo
Amélia Goes
AG
Orellana
Maristela Delgado
MD
Bonini de Palma
Patrícia Vianna
PV
Menezes
Camila C B O
CC
Covas
Dimas Tadeu
DT
Zago
Marco Antonio
MA
D000071916:AC133 Antigen; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D019070:Cell Lineage / Q000235:genetics; D016000:Cluster Analysis; D005312:Fetal Blood / Q000166:cytology; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000032:analysis; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D010455:Peptides / Q000032:analysis; D051881:Receptor, Notch1 / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
D000071916:AC133 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34; D006023:Glycoproteins; D016328:NF-kappa B; C497761:NOTCH1 protein, human; C000606023:PROM1 protein, human; D010455:Peptides; D051881:Receptor, Notch1; D014157:Transcription Factors