EFFECT OF TRANSFORMING GROWTH-FACTOR-BETA-1 AND BASIC FIBROBLAST GROWTH-FACTOR ON THE EXPRESSION OF CELL-SURFACE PROTEOGLYCANS IN HUMAN LUNG FIBROBLASTS - ENHANCED GLYCANATION AND FIBRONECTIN-BINDING OF CD44 PROTEOGLYCAN, AND DOWN-REGULATION OF GLYPICAN
M. Romaris et al., EFFECT OF TRANSFORMING GROWTH-FACTOR-BETA-1 AND BASIC FIBROBLAST GROWTH-FACTOR ON THE EXPRESSION OF CELL-SURFACE PROTEOGLYCANS IN HUMAN LUNG FIBROBLASTS - ENHANCED GLYCANATION AND FIBRONECTIN-BINDING OF CD44 PROTEOGLYCAN, AND DOWN-REGULATION OF GLYPICAN, Biochemical journal, 310, 1995, pp. 73-81
We have tested the effects of transforming growth factor-beta 1 (TGF-b
eta 1), basic fibroblast growth factor (bFGF) and TGF-beta 1 + bFGF on
the expression of the cell surface proteoglycans (CD44, syndecans and
glypican) in cultures of human lung fibroblasts (HLF). Cell surface p
roteoglycan expression was monitored by quantitative immunoprecipitati
on from metabolically labelled cells, Western and Northern blotting an
d evaluation of the glycanation of the proteoglycans. Stimulation of t
he cells with TGF-beta 1 increased the length of the chondroitin sulph
ate (CS) chains on CD44 (similar to 1.6-fold). bFGF, administered sole
ly, also increased the length of the CS chains on CD44 (similar to 1.4
-fold), whereas the combination of TGF-beta 1 + bFGF nearly doubled bo
th the length and the number of the CS chains on CD44. None of these t
reatments lead to changes in CD44 message or core-protein expression.
This enhanced glycanation of CD44 after the TGF-beta 1, bFGF and combi
ned treatments correlated with a 2-fold increase in the affinity of th
e proteoglycan for fibronectin but had no influence on the binding to
type I collagen. TGF-beta 1, alone or in combination with bFGF, also s
timulated the CS content of syndecan-1, but none of the other syndecan
s was significantly affected by any of the factors or combinations tes
ted. The expression of glypican however was significantly decreased (n
early halved) by the combination of TGF-beta 1 + bFGF, less so by TGF-
beta 1 and not at all by bFGF. This decrease occurred both at the leve
l of the message and of the core protein. These data demonstrate speci
fic and differential effects of TGF-beta 1 and bFGF on the structure,
expression and interactions of the cell surface proteoglycans of HLF.