title: Effects of CXCR1 and CXCR2 inhibition on expansion and differentiation of umbilical cord blood CD133(+) cells into megakaryocyte progenitor cells.
abstract: OBJECTIVE
  There have been various reports on the roles of CXC receptors (CXCR) in modulation of hematopoiesis. In the present study, we investigated the effects of CXCR1 and/or CXCR2 inhibition on expansion and differentiation of umbilical cord blood (UCB) CD133(+) cells into megakaryocytic progenitors.
  
  
  METHODS
  Purified UCB CD133(+) cells were cultured in a serum-free liquid culture either in the presence or absence of neutralizing anti-CXCR1 and/or anti-CXCR2 antibodies in combination with a conventional cytokine cocktail for up to 14days. Expression of megakaryocytic lineage markers (CD41 and CD61) and determination of ploidy level were determined by flowcytometry. In addition, colony-forming unit assay was performed using CD133(+) cultures in serum-free collagen-based medium containing the cytokine cocktail plus neutralizing CXCR1 and -R2 antibodies. Colony forming unit-megakaryocyte (CFU-MKs) and non-MKs were counted after immunocytochemistry staining on day 12.
  
  
  RESULTS
  We show that while simultaneous inhibition of both CXCR1 and -R2 causes a significant reduction in the fold expansion of UCB CD133(+) cells, it also leads to an increase in percentages of CD61(+), CD41(+), and CFU-MK populations.
  
  
  CONCLUSIONS
  CXCR1 and CXCR2 play significant roles in the suppression of megakaryopoiesis. We demonstrate that blocking of this suppressive effect by a simultaneous inhibition of both receptors can enhance the differentiation of UCB CD133(+) cells into megakayocytic progenitors.
authors.affiliation: Department of Immunology, Research Center, Iranian Blood Transfusion Organization, Tehran, Iran.
authors.forename: Elham Khalaf
authors.initials: EK
authors.lastname: Adeli
authors.forename: Hassan
authors.initials: H
authors.lastname: Abolghasemi
authors.forename: Massumeh
authors.initials: M
authors.lastname: Ebtekar
authors.forename: Zahra
authors.initials: Z
authors.lastname: Pourpak
authors.forename: Maryam
authors.initials: M
authors.lastname: Kheirandish
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D002469:Cell Separation; D002478:Cells, Cultured; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D055016:Megakaryocyte Progenitor Cells / Q000502:physiology*; D010455:Peptides / Q000276:immunology*; D011003:Ploidies; D011247:Pregnancy; D023062:Receptors, Interleukin-8A / Q000276:immunology*; D023063:Receptors, Interleukin-8B / Q000276:immunology*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D015415:Biomarkers; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B