Expression of neural cell adhesion molecule and polysialic acid in human bone marrow-derived mesenchymal stromal cells

• Published in: Stem cell research & therapy Vol. 7; no. 1; p. 113
• Main Authors: Skog, Maria S, Nystedt, Johanna, Korhonen, Matti, Anderson, Heidi, Lehti, Timo A, Pajunen, Maria I, Finne, Jukka
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 15.08.2016; BioMed Central
• Subjects: Biomarkers - metabolism; Bone Marrow - metabolism; CD56 Antigen - metabolism; Cell adhesion molecules; Cell Line, Tumor; Cell Lineage - physiology; Gene expression; Genetic aspects; Growth; Health aspects; Humans; Mesenchymal Stromal Cells - metabolism; Neural Cell Adhesion Molecules - metabolism; Neurons - metabolism; Properties; RNA, Messenger - metabolism; Sialic Acids - metabolism; Sialyltransferases - metabolism; Stem cells; Bone marrow; Mesenchymal stromal cell; Clinical grade; Neural cell adhesion molecule; Polysialic acid
• ISSN: 1757-6512; 1757-6512
• DOI: 10.1186/s13287-016-0373-5

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.