Heparin is a unique marker of progenitors in the glial cell lineage.
The oligodendrocyte-type-2 astrocyte progenitor cells (precursors of oligodendrocytes and type-2 astrocytes) are an excellent system in which to study differentiation as they can be manipulated in vitro. Maintenance of oligodendrocyte-type-2 astrocyte progenitor cells requires basic fibroblast growth factor, a growth factor whose action normally depends on a heparan sulfate coreceptor. Biochemical analysis revealed a most surprising result: that the oligodendrocyte-type-2 astrocyte progenitors did not synthesize heparan sulfate, the near ubiquitous N-sulfated cell surface polysaccharide, but the chemically related heparin in a form that was almost completely N- and O-sulfated. The heparin was detected in the pericellular fraction of the cells and the culture medium. In contrast the differentiated glial subpopulations (oligodendrocytes and type-2 astrocytes) synthesized typical heparan sulfate but with distinctive fine structural features for each cell type. Thus heparin is a unique differentiation marker in the glial lineage. Previously heparin has been found only in a subset of mature mast cells called the connective tissue mast cells. Its presence within the developing nervous system on a precise population of progenitors may confer specific and essential recognition properties on those cells in relation to binding soluble growth and/or differentiation factors and the extracellular matrix.
Stringer
S E
SE
Cancer Research Campaign, Paterson Institute of Cancer Research, Christie Hospital, Wilmslow Road, Manchester M20 4BX, United Kingdom. sstringer@picr.man.ac.uk
Mayer-Proschel
M
M
Kalyani
A
A
Rao
M
M
Gallagher
J T
JT
D000818:Animals; D015415:Biomarkers; D002454:Cell Differentiation; D019070:Cell Lineage; D002478:Cells, Cultured; D006493:Heparin / Q000096:biosynthesis*; D009836:Oligodendroglia / Q000166:cytology* / Q000378:metabolism*; D051381:Rats; D013234:Stem Cells / Q000166:cytology*
D015415:Biomarkers; D006493:Heparin