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N‐linked sialyated sugar receptors support haematopoietic cell‐osteoblast adhesions
Author(s) -
Crean S. M.,
Meneski J. P.,
Hullinger T. G.,
Reilly M. J.,
DeBoever E. H.,
Taichman R. S.
Publication year - 2004
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2003.04786.x
Subject(s) - haematopoiesis , microbiology and biotechnology , stromal cell , biology , cell adhesion , cell adhesion molecule , bone marrow , stem cell , cell , biochemistry , immunology , cancer research
Summary Haematopoietic progenitor cells proliferate and develop predominantly when they adhere to bone marrow stromal cells such as osteoblasts. Therefore, changes in adhesion may be a common mechanism by which stem cells survive, mature and properly traffic between the bone marrow and the circulation. To characterize these adhesion molecules, we reduced the bone marrow cavity to a simple adhesion assay between KG1a (a CD34 + haematopoietic cell line) and osteosarcoma monolayers (MG‐63 or SaOS‐2). The data demonstrated that adhesion was mediated by cell‐to‐cell rather than cell‐to‐matrix contact, was sensitive to trypsin, calcium chelators and glycosylation inhibitors. Selective pretreatment attributed the constitutive binding to N‐linked glycans on KG1a. When carboprocessing was inhibited later at the high mannose intermediate (via deoxymannojirimycin), adhesion was retained. Surprisingly, binding of KG1a to SaOS‐2 increased past constitutive levels as doses of tunicamycin or deoxymannojirimycin dropped. Selective pretreatment suggested that this ‘inducible’ binding resides with molecule(s) on SaOS‐2. If the terminal sialic acid was digested (via neuraminidase), this induced response was duplicated. These data, verified in primary cells, suggest that the initial tethering between blood and bone cells in this model is probably due to heavily glycosylated, rapidly processed protein(s) on both cell types.