title: CD14-/CD34+ is the founding population of umbilical cord blood-derived endothelial progenitor cells and angiogenin1 is an important factor promoting the colony formation.
abstract: The origin of endothelial progenitor cells (EPCs) in umbilical cord blood (UCB) is unknown. In this study, we explored the origin of UCB-derived EPCs by culturing CD14+ or CD14- subpopulation separately and co-culturing these two subpopulations either with or without transwells. We found no colony formation with CD14+ or CD14- subpopulation alone, but there were EPC colonies observed in direct co-cultures of both subpopulations. Transwell culture system was used to further study the effect of cytokines on EPC colony formation. We observed the presence of EPC colonies derived from CD14- subpopulation in the presence of CD14+ subpopulation in the upper compartment whereas there was no colony generated from CD14+ subpopulation with CD14- subpopulation in the upper compartment. Therefore, CD14- subpopulation is likely to be the origin of EPCs and EPC colony derivation requires cytokines released from CD14+ subpopulation. We further characterized the founding population of UCB-derived EPCs by separating CD14- subpopulation into CD14-/CD34+ and CD14-/CD34- subpopulations. There were colonies observed only in co-cultures of CD14+ with CD14-/CD34+ subpopulation but not with CD14-/CD34- subpopulation either with or without transwells. We screened 42 cytokines involving in angiogenesis using an ELISA array in the supernatant collected from CD14+ compared to CD14- subpopulations. We found consistently the presence of angiogenin1 in the supernatant of CD14+ subpopulation but not in that of CD14- subpopulation. The addition of angiogenin1 in culture of CD14- subpopulation yielded EPC colonies. We conclude that UCB-derived EPCs are confined to CD14-/CD34+ subpopulation and angiogenin1 released from CD14+ subpopulation may be an important factor promoting the EPC colony formation.
authors.affiliation: Department of Immunology, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sakchai
authors.initials: S
authors.lastname: Sudchada
authors.forename: Pakpoom
authors.initials: P
authors.lastname: Kheolamai
authors.forename: Yaowalak
authors.initials: Y
authors.lastname: U-Pratya
authors.forename: Methichit
authors.initials: M
authors.lastname: Chayosumrit
authors.forename: Aungkura
authors.initials: A
authors.lastname: Supokawej
authors.forename: Sirikul
authors.initials: S
authors.lastname: Manochantr
authors.forename: Chairat
authors.initials: C
authors.lastname: Tantrawatpan
authors.forename: Hathaitip
authors.initials: H
authors.lastname: Sritanaudomchai
authors.forename: Surapol
authors.initials: S
authors.lastname: Issaragrisil
mesh_terms: D018952:Antigens, CD34 / Q000235:genetics / Q000276:immunology*; D002469:Cell Separation; D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D005312:Fetal Blood / Q000166:cytology*; D006801:Humans; D007231:Infant, Newborn; D007963:Leukocytes, Mononuclear / Q000166:cytology; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000276:immunology*; D012259:Ribonuclease, Pancreatic / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
chemical_list: D018952:Antigens, CD34; D018950:Lipopolysaccharide Receptors; C046366:angiogenin; D012259:Ribonuclease, Pancreatic