Expression of genes regulating angiogenesis in human circulating hematopoietic cord blood CD34+/CD133+ cells.
OBJECTIVE
Human CD34+ cells represent a heterogeneous population of immature cells which may differentiate to various cell types. The aim of the study was to determine angiogenesis regulating genes expression in CD34+ cells, their subpopulations, and during their differentiation induced by hematopoietic growth factors.


METHODS
We have measured the expression of angiogenesis regulating genes angiopoietin-1 (Ang-1), angiopoietin-1 (Ang-2) and their receptor Tie-2, vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 and VEGFR-2 in sorted population of CD34+ and CD34+/CD133+ cells from human cord blood and bone marrow, and in their differentiating progeny, using real time reverse transcriptase polymerase chain reaction. The hematopoietic differentiation of CD34+ cells was induced in semisolid or liquid differentiation supporting media containing appropriate hematopoietic growth factors.


RESULTS
A higher expression of Ang-1, Ang-2, and Tie-2 mRNAs was detected in CD34+/CD133+ cord blood cells as compared with CD34-/CD133- fraction, but no expression of these genes was detected in burst-forming unit erythroid (BFU-E) nor colony-forming unit granulocyte macrophage (CFU-GM) colonies. The level of Ang-1 and Tie-2 mRNAs, but not that of Ang-2 mRNA gradually decreased during a 14-d incubation of cord blood CD34+ cells in a liquid culture. A significantly higher expression of VEGF mRNA was in BFU-E as compared with CFU-GM cell colonies and CD34+/CD133+ cells. VEGFR-1 mRNA was equally expressed in CD34+/CD133+ and CD34-/CD133- cells as well as in BFU-E and CFU-GM colonies. Expression of VEGFR-2 mRNA was detected at the borderline of method sensitivity only in CD34+/CD133+ cells.


CONCLUSIONS
CD34+/CD133+ cord blood cells express Ang-1, Ang-2 and VEGF as well as their receptor mRNAs, suggesting a role of these cells in regulation both angiopoiesis and hematopoiesis.
Pomyje
Jirí
J
Department of Pathophysiology, 1st Medical Faculty, Charles University Prague, Czech Republic. jpomyje@lf1.cuni.cz
Zivný
Jan
J
Sefc
Ludek
L
Plasilová
Magdalena
M
Pytlík
Robert
R
Necas
Emanuel
E
D000071916:AC133 Antigen; D043925:Angiogenesis Inducing Agents / Q000235:genetics; D042683:Angiopoietin-1; D042702:Angiopoietin-2; D015703:Antigens, CD; D018952:Antigens, CD34 / Q000097:blood; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D005312:Fetal Blood / Q000166:cytology; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000097:blood; D006410:Hematopoiesis / Q000235:genetics; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D018919:Neovascularization, Physiologic / Q000235:genetics*; D010455:Peptides / Q000097:blood; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D042787:Receptor, TIE-2
D000071916:AC133 Antigen; C467630:ANGPT1 protein, human; D043925:Angiogenesis Inducing Agents; D042683:Angiopoietin-1; D042702:Angiopoietin-2; D015703:Antigens, CD; D018952:Antigens, CD34; D006023:Glycoproteins; D016298:Hematopoietic Cell Growth Factors; D008562:Membrane Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases; D042787:Receptor, TIE-2