P. Conget et Jj. Minguell, IL-3 INCREASES SURFACE PROTEOGLYCAN SYNTHESIS IN HEMATOPOIETIC PROGENITORS AND THEIR ADHESIVENESS TO THE HEPARIN-BINDING DOMAIN OF FIBRONECTIN, British Journal of Haematology, 89(1), 1995, pp. 1-7
Haemopoietic progenitor cells (HPC) synthesize and accumulate a single
type of membrane-associated chondroitin sulphate proteoglycan (MA-PG)
, which participates in HPC adhesiveness to fibronectin by interacting
with its heparin-binding domain. Shortly after incubating cells with
IL-3, we observed an increase in MA-PG synthesis in the multipotent (F
DCP-mix) but not in the bipotent (FDCP-1) progenitor cell line. The ch
arge density, hydrodynamic size, nature of the glycosaminoglycan (GAG)
chains and stability of MA-PG from IL-3-treated and non-treated FDCP-
mix cells were the same, suggesting that IL-3 affects the amount of MA
-PG. The latter was evaluated by now cytometry using monoclonal antibo
dies to the core protein and GAG residues. In all cases the mean fluor
escence intensities were higher for IL-3-treated than for untreated ce
lls. Cell adhesion studies to dishes coated with the fibronectin 40 kD
fragment, containing the heparin-binding domain, demonstrated that ad
hesiveness of IL-3-treated cells was higher than that of untreated cel
ls. These results suggest that in multipotent haemopoietic cells IL-3
regulates the amount of membrane-associated proteoglycans, which in tu
rn modify the adhesive interactions of cells with the heparin-binding
domain of fibronectin.