title: Evaluation of umbilical cord blood CD34+ hematopoietic stem cells expansion with inhibition of TGF-β receptorII in co-culture with bone marrow mesenchymal stromal cells.
abstract: BACKGROUND
  Umbilical cord blood (UCB) is an important source of hematopoietic stem cells (HSCs). However, low number of HSCs in UCB has been an obstacle for adult hematopoietic stem cell transplantation. The expansion of HSCs in culture is one approach to overcome this problem. In this study, we investigated the expansion of UCB-HSCs by using human bone marrow mesenchymal stromal cells (MSCs) as feeder layer as well as inhibiting the TGF-β signaling pathway through reduction of TGF-βRII expression.
  
  
  METHODS
  CD34(+) cells were isolated from UCB and transfected by SiRNA targeting TGF-βRII mRNA. CD34(+) cells were expanded in four culture media with different conditions, including 1) expansion of CD34(+) cells in serum free medium containing growth factors, 2) expansion of cells transfected with SiRNA targeting TGF-βRII in medium containing growth factors, 3) expansion of cells in presence of growth factors and MSCs, 4) expansion of cells transfected with SiRNA targeting TGF-βRII on MSCs feeder layer in medium containing growth factors. These culture conditions were evaluated for the number of total nucleated cells (TNCs), CD34 surface marker as well as using CFU assay on 8th day after culture.
  
  
  RESULTS
  The fold increase in CD34(+) cells, TNCs, and colony numbers (71.8±6.9, 93.2±10.2 and 128±10, respectively) was observed to be highest in fourth culture medium compared to other culture conditions. The difference between number of cells in four culture media in 8th day compared to unexpanded cells (0day) before expansion was statistically significant (P<0.05).
  
  
  CONCLUSIONS
  The results showed that transfection of CD34(+) cells with SiRNA targeting TGF-βRII and their co-culture with MSCs could considerably increase the number of progenitors. Therefore, this method could be useful for UCB-HSCs expansion.
authors.affiliation: Department of Hematology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Saman
authors.initials: S
authors.lastname: Sohrabi Akhkand
authors.affiliation: Blood Transfusion Research Center, High Institute for Education and Research in Transfusion Medicine, Tehran, Iran.
authors.forename: Naser
authors.initials: N
authors.lastname: Amirizadeh
authors.affiliation: Blood Transfusion Research Center, High Institute for Education and Research in Transfusion Medicine, Tehran, Iran.
authors.forename: Mahin
authors.initials: M
authors.lastname: Nikougoftar
authors.affiliation: Department of Human Anatomy and Cell Science, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: Javad
authors.initials: J
authors.lastname: Alizadeh
authors.affiliation: Cellular and Molecular Research Center, Department of Hematology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran. Electronic address: farhadz20@yahoo.co.uk.
authors.forename: Farhad
authors.initials: F
authors.lastname: Zaker
authors.affiliation: Colorectal Research center, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Arash
authors.initials: A
authors.lastname: Sarveazad
authors.affiliation: Cellular and Molecular Research Center, Department of Anatomy, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Joghataei
authors.affiliation: Research Center of Pediatric Infectious Diseases, Rasoul-e-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Faramarzi
mesh_terms: D000328:Adult; D018952:Antigens, CD34 / Q000235:genetics; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D018920:Coculture Techniques; D061252:Feeder Cells; D005312:Fetal Blood / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D016212:Transforming Growth Factor beta / Q000235:genetics
chemical_list: D018952:Antigens, CD34; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II
keywords: CD34+ hematopoietic stem cells; Cord blood; Mesenchymal stromal cells