title: Neural differentiation potential of human bone marrow-derived mesenchymal stromal cells: misleading marker gene expression.
abstract: BACKGROUND
  In contrast to pluripotent embryonic stem cells, adult stem cells have been considered to be multipotent, being somewhat more restricted in their differentiation capacity and only giving rise to cell types related to their tissue of origin. Several studies, however, have reported that bone marrow-derived mesenchymal stromal cells (MSCs) are capable of transdifferentiating to neural cell types, effectively crossing normal lineage restriction boundaries. Such reports have been based on the detection of neural-related proteins by the differentiated MSCs. In order to assess the potential of human adult MSCs to undergo true differentiation to a neural lineage and to determine the degree of homogeneity between donor samples, we have used RT-PCR and immunocytochemistry to investigate the basal expression of a range of neural related mRNAs and proteins in populations of non-differentiated MSCs obtained from 4 donors.
  
  
  RESULTS
  The expression analysis revealed that several of the commonly used marker genes from other studies like nestin, Enolase2 and microtubule associated protein 1b (MAP1b) are already expressed by undifferentiated human MSCs. Furthermore, mRNA for some of the neural-related transcription factors, e.g. Engrailed-1 and Nurr1 were also strongly expressed. However, several other neural-related mRNAs (e.g. DRD2, enolase2, NFL and MBP) could be identified, but not in all donor samples. Similarly, synaptic vesicle-related mRNA, STX1A could only be detected in 2 of the 4 undifferentiated donor hMSC samples. More significantly, each donor sample revealed a unique expression pattern, demonstrating a significant variation of marker expression.
  
  
  CONCLUSIONS
  The present study highlights the existence of an inter-donor variability of expression of neural-related markers in human MSC samples that has not previously been described. This donor-related heterogeneity might influence the reproducibility of transdifferentiation protocols as well as contributing to the ongoing controversy about differentiation capacities of MSCs. Therefore, further studies need to consider the differences between donor samples prior to any treatment as well as the possibility of harvesting donor cells that may be inappropriate for transplantation strategies.
authors.affiliation: Department of Neurology, RWTH Aachen University, Aachen, Germany. kmontzka@ukaachen.de
authors.forename: Katrin
authors.initials: K
authors.lastname: Montzka
authors.forename: Nina
authors.initials: N
authors.lastname: Lassonczyk
authors.forename: Beate
authors.initials: B
authors.lastname: Tschöke
authors.forename: Sabine
authors.initials: S
authors.lastname: Neuss
authors.forename: Tobias
authors.initials: T
authors.lastname: Führmann
authors.forename: Rachelle
authors.initials: R
authors.lastname: Franzen
authors.forename: Ralf
authors.initials: R
authors.lastname: Smeets
authors.forename: Gary A
authors.initials: GA
authors.lastname: Brook
authors.forename: Michael
authors.initials: M
authors.lastname: Wöltje
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000502:physiology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D004676:Myelin Basic Protein / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D055495:Neurogenesis / Q000502:physiology*; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000502:physiology*; D050827:Syntaxin 1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D015415:Biomarkers; D004268:DNA-Binding Proteins; C513076:EN1 protein, human; D018398:Homeodomain Proteins; D007381:Intermediate Filament Proteins; C475491:MAP1B protein, human; D008869:Microtubule-Associated Proteins; D004676:Myelin Basic Protein; C577484:NES protein, human; C539882:NR4A2 protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D012333:RNA, Messenger; D017448:Receptors, Dopamine D2; C494212:STX1A protein, human; D050827:Syntaxin 1; D014157:Transcription Factors; D010751:Phosphopyruvate Hydratase