title: Expression of neural cell adhesion molecule and polysialic acid in human bone marrow-derived mesenchymal stromal cells.
abstract: In order to develop novel clinical applications and to gain insights into possible therapeutic mechanisms, detailed molecular characterization of human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) is needed. Neural cell adhesion molecule (NCAM, CD56) is a transmembrane glycoprotein modulating cell-cell and cell-matrix interactions. An additional post-translational modification of NCAM is the α2,8-linked polysialic acid (polySia). Because of its background, NCAM is often considered a marker of neural lineage commitment. Generally, hBM-MSCs are considered to be devoid of NCAM expression, but more rigorous characterization is needed.
  
  
  
  We have studied NCAM and polySia expression in five hBM-MSC lines at mRNA and protein levels. Cell surface localization was confirmed by immunofluorescence staining and expression frequency in the donor-specific lines by flow cytometry. For the detection of poorly immunogenic polySia, a fluorochrome-tagged catalytically defective enzyme was employed.
  
  
  
  All five known NCAM isoforms are expressed in these cells at mRNA level and the three main isoforms are present at protein level. Both polysialyltransferases, generally responsible for NCAM polysialylation, are expressed at mRNA level, but only very few cells express polySia at the cell surface.
  
  
  
  Our results underline the need for a careful control of methods and conditions in the characterization of MSCs. This study shows that, against the generally held view, clinical-grade hBM-MSCs do express NCAM. In contrast, although both polysialyltransferase genes are transcribed in these cells, very few express polySia at the cell surface. NCAM and polySia represent new candidate molecules for influencing MSC interactions.
authors.affiliation: Biochemistry and Biotechnology, Department of Biosciences, University of Helsinki, P.O. Box 56, FI-00014, Helsinki, Finland. maria.skog@helsinki.fi.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Skog
authors.affiliation: Cell Therapy Services, Finnish Red Cross Blood Service, Kivihaantie 7, FI-00310, Helsinki, Finland.
authors.forename: Johanna
authors.initials: J
authors.lastname: Nystedt
authors.affiliation: Cell Therapy Services, Finnish Red Cross Blood Service, Kivihaantie 7, FI-00310, Helsinki, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Korhonen
authors.affiliation: Biochemistry and Biotechnology, Department of Biosciences, University of Helsinki, P.O. Box 56, FI-00014, Helsinki, Finland.|Present Address: Genoscoper Laboratories Oy, P.O. Box 1040, FI-00251, Helsinki, Finland.
authors.forename: Heidi
authors.initials: H
authors.lastname: Anderson
authors.affiliation: Biochemistry and Biotechnology, Department of Biosciences, University of Helsinki, P.O. Box 56, FI-00014, Helsinki, Finland.
authors.forename: Timo A
authors.initials: TA
authors.lastname: Lehti
authors.affiliation: Biochemistry and Biotechnology, Department of Biosciences, University of Helsinki, P.O. Box 56, FI-00014, Helsinki, Finland.|Present Address: Department of Bacteriology and Immunology, Medicum, Research Programs Unit, Immunobiology, University of Helsinki, P.O. Box 21, FI-00014, Helsinki, Finland.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Pajunen
authors.affiliation: Biochemistry and Biotechnology, Department of Biosciences, University of Helsinki, P.O. Box 56, FI-00014, Helsinki, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Finne
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001853:Bone Marrow / Q000378:metabolism*; D019002:CD56 Antigen / Q000378:metabolism*; D045744:Cell Line, Tumor; D019070:Cell Lineage / Q000502:physiology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019002:CD56 Antigen; C522918:NCAM1 protein, human; D019006:Neural Cell Adhesion Molecules; D012333:RNA, Messenger; D012794:Sialic Acids; C021319:polysialic acid; D012799:Sialyltransferases
keywords: Bone marrow; Clinical grade; Mesenchymal stromal cell; Neural cell adhesion molecule; Polysialic acid