Growth regulation in scleroderma fibroblasts: increased response to transforming growth factor-beta 1.
We investigated the responses of normal and scleroderma fibroblasts to various growth factors, especially transforming growth factor-beta 1 (TGF-beta 1). The effects of various growth factors on [3H]thymidine incorporation in normal and scleroderma fibroblasts were examined. [125I]-labeled platelet-derived growth factor (PDGF)-BB binding in scleroderma and normal fibroblasts was examined both in the presence and absence of TGF-beta 1 (1 ng/ml). Cytoplasmic protein was isolated and analyzed by Western blotting. Total RNA from fibroblasts was also isolated and analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) using specific primer sets. Mitogenic responses to TGF-beta 1 (0.33-1 ng/ml) in seven scleroderma fibroblast strains were significantly greater than those in normal controls. [125I]-PDGF-BB binding to scleroderma fibroblasts was increased after TGF-beta 1 stimulation. The increased response to TGF-beta 1 was shown to be mediated through PDGF-like protein induction; TGF-beta 1-treated scleroderma fibroblasts produced greater amounts of 36-kD PDGF-like protein, which was reported previously as connective tissue growth factor (CTGF), than did TGF-beta 1-treated normal fibroblasts. TGF-beta 1 treatment also upregulated PDGF-alpha receptor expression in scleroderma fibroblasts but not in normal dermal fibroblasts. mRNA expression of CTGF and PDGF-alpha receptor was correlated with the above protein expression. These observations suggest that the increased growth response to TGF-beta 1 in scleroderma fibroblasts is mediated through the induction of CTGF and PDGF-alpha receptor.
Kikuchi
K
K
Department of Dermatology, Faculty of Medicine, University of Tokyo, Japan.
Kadono
T
T
Ihn
H
H
Sato
S
S
Igarashi
A
A
Nakagawa
H
H
Tamaki
K
K
Takehara
K
K
D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis; D017479:Receptors, Platelet-Derived Growth Factor / Q000096:biosynthesis; D012595:Scleroderma, Systemic / Q000473:pathology*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor