Effects of interferon-gamma on human subconjunctival fibroblasts in the presence of TGFbeta1: reversal of TGFbeta-stimulated collagen production.
BACKGROUND
We examined the effects of interferon-gamma (IFN-gamma) on protein production of extracellular matrix (ECM) components in cultured human subconjunctival fibroblasts or those stimulated by exogenous transforming growth factor beta1 (TGFbeta1). IFN-gamma reportedly up-regulates Smad7, an inhibitory mediator of TGFbeta-Smad signaling, and blocks TGFbeta effects.


METHODS
Proliferation and migration as well as the ultrastructure of these cells were examined in the presence and absence of IFN-gamma. Cell migration was examined using an in vitro wound healing model in monolayer fibroblast cultures.


RESULTS
The results showed that IFN-gamma reduced ECM production in normal subconjunctival fibroblasts, as well as in those treated with TGFbeta1, below the control levels. IFN-gamma had no effect on cell proliferation and fibroblast ultrastructure. On the other hand, IFN-gamma delayed defect closure in monolayer cell sheets in a dose-dependent manner. Immunohistochemistry also revealed that the addition of IFN-gamma attenuated the translocation of Smads2/4 into the nuclei of TGFbeta1-treated subconjunctival fibroblasts.


CONCLUSIONS
These findings suggest that IFN-gamma may be clinically effective in attenuating excessive ECM accumulation in conjunctiva after ocular surgery and in the presence of inflammatory ocular surface disorder. IFN-gamma modulates the Smads2/4 pathway of TGFbeta1 signal transduction toward the up-regulation of ECM components.
Yamanaka
Osamu
O
Department of Ophthalmology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-0012, Japan. yamanaka@wakayama-med.ac.jp
Saika
Shizuya
S
Okada
Yuka
Y
Ooshima
Akira
A
Ohnishi
Yoshitaka
Y
D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis*; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004338:Drug Combinations; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000096:biosynthesis; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007797:Laminin / Q000096:biosynthesis; D015398:Signal Transduction; D051899:Smad2 Protein; D051901:Smad4 Protein; D015534:Trans-Activators / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation; D014945:Wound Healing / Q000187:drug effects
D004268:DNA-Binding Proteins; D004338:Drug Combinations; D005353:Fibronectins; D007797:Laminin; C497782:SMAD2 protein, human; C497796:SMAD4 protein, human; D051899:Smad2 Protein; D051901:Smad4 Protein; C508960:TGFB1 protein, human; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D007371:Interferon-gamma; D003094:Collagen