Interleukin-7 modulates extracellular matrix production and TGF-beta signaling in cultured human subconjunctival fibroblasts.
OBJECTIVE
We examined the role of interleukin-7 (IL-7) in modulation of production of extracellular matrix (ECM), immunolocalization of Smads, and cell migration and expressions of transforming growth factor-beta (TGF-beta) in cultured human subconjunctival fibroblasts. IL-7 is capable of inducing Smad7, an inhibitory Smad that interferes with TGF-beta/Smad signal.


METHODS
The effects of IL-7 on ECM production, immunolocalization of Smads, type I collagen, fibronectin, alpha -smooth muscle actin (alpha -SMA), and cell migration were examined in human subconjunctival fibroblast culture with or without TGF-beta1. ECM production, such as type I collagen and fibronectin, was measured by immunoassay or real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Cell migration was examined using an in vitro wound model in monolayer cultures. We also examined the effects of IL-7, PKC inhibitor, and STAT inhibitor on the expressions of TGF-beta1 and type I collagen alpha1 chain (col1A1) m-RNA by using real-time RT-PCR.


RESULTS
IL-7 reduced the ECM production much more markedly in the cells treated with TGF-1beta than in the control fibroblasts. TGF-beta1 strongly showed immunolocalization of phospho-Smad2, and IL-7 also showed immunolocalization of Smad7 in the nuclei. The immunoreactivities of alpha -SMA and fibronectin were weaker in the presence of IL-7 than in the control cells. IL-7 also delayed defect closure in the monolayer cell sheets, and the delay was recovered by exogenous type I collagen or fibronectin. Each of IL-7, BIS I, or AGS 490 reduced the mRNA expressions of TGF-beta1 and col1A1.


CONCLUSIONS
These findings indicate that IL-7 is involved in ECM production in the subconjunctival fibroblasts activated by exogenous TGF-beta1, suggesting that administration of IL-7 can be a novel therapeutic strategy in preventing undesirable bleb scar formation during healing after filtration surgery.
Yamanaka
Osamu
O
Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan. yamanaka@wakayama-med.ac.jp
Saika
Shizuya
S
Ikeda
Kazuo
K
Miyazaki
Ken-Ichi
K
Ohnishi
Yoshitaka
Y
Ooshima
Akira
A
D000199:Actins / Q000235:genetics; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics; D006801:Humans; D015851:Interleukin-7 / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051785:Smad Proteins / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D053773:Transforming Growth Factor beta1; D014945:Wound Healing / Q000187:drug effects
D000199:Actins; D024042:Collagen Type I; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D015851:Interleukin-7; D012333:RNA, Messenger; D051785:Smad Proteins; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1