title: Umbilical cord blood-derived mesenchymal stem cells consist of a unique population of progenitors co-expressing mesenchymal stem cell and neuronal markers capable of instantaneous neuronal differentiation.
abstract: BACKGROUND
  Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) are self-renewing multipotent progenitors with the potential to differentiate into multiple lineages of mesoderm, in addition to generating ectodermal and endodermal lineages by crossing the germline barrier. In the present study we have investigated the ability of UCB-MSCs to generate neurons, since we were able to observe varying degrees of neuronal differentiation from a few batches of UCB-MSCs with very simple neuronal induction protocols whereas other batches required extensive exposure to combination of growth factors in a stepwise protocol. Our hypothesis was therefore that the human UCB-MSCs would contain multiple types of progenitors with varying neurogenic potential and that the ratio of the progenitors with high and low neurogenic potentials varies in different batches of UCB.
  
  
  METHODS
  In total we collected 45 UCB samples, nine of which generated MSCs that were further expanded and characterized using immunofluorescence, fluorescence-activated cell sorting and RT-PCR analysis. The neuronal differentiation potential of the UCB-MSCs was analyzed with exposure to combination of growth factors.
  
  
  RESULTS
  We could identify two different populations of progenitors within the UCB-MSCs. One population represented progenitors with innate neurogenic potential that initially express pluripotent stem cell markers such as Oct4, Nanog, Sox2, ABCG2 and neuro-ectodermal marker nestin and are capable of expanding and differentiating into neurons with exposure to simple neuronal induction conditions. The remaining population of cells, typically expressing MSC markers, requires extensive exposure to a combination of growth factors to transdifferentiate into neurons. Interesting to note was that both of these cell populations were positive for CD29 and CD105, indicating their MSC lineage, but showed prominent difference in their neurogenic potential.
  
  
  CONCLUSIONS
  Our results suggest that the expanded UCB-derived MSCs harbor a small unique population of cells that express pluripotent stem cell markers along with MSC markers and possess an inherent neurogenic potential. These pluripotent progenitors later generate cells expressing neural progenitor markers and are responsible for the instantaneous neuronal differentiation; the ratio of these pluripotent marker expressing cells in a batch determines the innate neurogenic potential.
authors.forename: Mundackal S
authors.initials: MS
authors.lastname: Divya
authors.forename: George E
authors.initials: GE
authors.lastname: Roshin
authors.forename: Thulasi S
authors.initials: TS
authors.lastname: Divya
authors.forename: Vazhanthodi Abdul
authors.initials: VA
authors.lastname: Rasheed
authors.forename: Thankayyan R
authors.initials: TR
authors.lastname: Santhoshkumar
authors.forename: Kandathil E
authors.initials: KE
authors.lastname: Elizabeth
authors.forename: Jackson
authors.initials: J
authors.lastname: James
authors.forename: Radhakrishna M
authors.initials: RM
authors.lastname: Pillai
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D015703:Antigens, CD / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D000071317:Nanog Homeobox Protein; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000166:cytology; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D015703:Antigens, CD; D015415:Biomarkers; D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D009363:Neoplasm Proteins; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors