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Transforming Growth Factor-Î1 Induces Heparan Sulfate 6-O-Endosulfatase 1 Expression in Vitro and in Vivo
Transforming growth factor (TGF)-Ì1 plays an important role in the
development of pulmonary fibrosis. In this study we examined the
relationship between TGF-?1 stimulation and the expression of heparan
sulfate (HS) 6-O-endosulfatase 1 (Sulf1) in cultured normal human lung
fibroblasts (NHLFs) and in murine lungs in vivo. By removing 6-O-sulfates
from specific HS intrachain sites on the cell surface, Sulf1 has been shown
to modulate the activities of many HS binding growth factors and morphogens
including fibroblast growth factor (FGF)-2. Real time reverse
transcription-PCR analysis revealed that TGF-?1 increased Sulf1 expression
in NHLFs in a dose- and time-dependent manner which was accompanied by a
decrease in 6-O-sulfated disaccharides as revealed by high performance
liquid chromatography analysis. Decreased ERK activation after FGF-2
stimulation was observed in TGF-Î1-treated NHLFs compared with control cells
without changes in HS-dependent FGF-2 binding or FGF-2-FR1c complex
formation. To study the function of Sulf1, negative control or
Sulf1-specific small interference RNA (siRNA)-transfected NHLFs were
stimulated with TGF-Î1. Enhanced Smad2/3 phosphorylation and elevated total
Smad2 protein level were observed in Sulf1 siRNA-transfected cells and were
accompanied by enhanced expression of {alpha}-smooth muscle actin and
fibronectin. In addition, Sulf1 siRNA transfection enhanced the
anti-proliferative effect of TGF-?1. Finally Sulf1 expression was
up-regulated in the lungs of mice treated with adenovirus encoding active
TGF-Î1. Taken together, our data indicate that Sulf1 is a TGF-Î1-responsive
gene both in vitro and in vivo and may function as a negative regulator of
TGF-Î1-induced fibrogenesis.
This work was supported, in whole or in part, by National Institutes of
Health Grant HL083480. The costs of publication of this article were
defrayed in part by the payment of page charges. This article must therefore
be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734
solely to indicate this fact.
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