PROTEOGLYCAN SYNTHESIS IN HUMAN AND MURINE HEMATOPOIETIC PROGENITOR SELL LINES - ISOLATION AND CHARACTERIZATION OF A HEPARAN-SULFATE PROTEOGLYCAN AS A MAJOR PROTEOGLYCAN FROM THE HUMAN HEMATOPOIETIC-CELL LINE TF-1

Proteoglycans of bone-marrow stromal cells and their extracellular mat rix are important components of the microenvironment of haematopoietic tissues. Proteoglycans might also be involved in the interaction of h aematopoietic stem and stromal cells. Recently, several studies have b een reported on the proteoglycan synthesis of stromal cells, but littl e is known about the proteoglycan synthesis of haematopoietic stem or progenitor cells. Here we report on the isolation and characterization of proteoglycans from two haematopoietic progenitor cell lines, the m urine FDCP-Mix A4 and the human TF-1 cell line. Proteoglycans were iso lated from metabolically labelled cells and purified by several chroma tographic steps, including anion-exchange and size-exclusion chromatog raphy. Biochemical characterization was performed by electrophoresis o r gel-filtration chromatography before and after digestion with glycos aminoglycan-specific enzymes or HNO2 treatment. Whereas FDCP-Mix A4 ce lls synthesize a homogeneous chondroitin 4-sulphate proteoglycan, isol ation and characterization of proteoglycans from the human cell line T F-1 revealed, that TF-1 cells synthesize, in addition to a chondroitin sulphate proteoglycan, a heparan sulphate proteoglycan as major prote oglycan. For this heparan sulphate proteoglycan a core protein size of approx. 59 kDa was determined. Immunochemical analysis of this hepara n sulphate proteoglycan revealed that it is not related to the syndeca n family nor to glypican.