Gene transfer of Smad7 modulates injury-induced conjunctival wound healing in mice.
OBJECTIVE
Smad7 is a molecule that blocks the Smad2/3 signal. Herein, we examined the effects of Smad7 gene introduction on post-injury conjunctival wound healing in mice. Its effects on the cultured human subconjunctival fibroblasts (SCFs) were also investigated.


METHODS
A circumferential incision was made in the equatorial conjunctiva by using scissors in the right eye of fully anesthetized adult C57BL/6 mice (n=72). Smad7 cDNA-expressing adenoviral vector was topically applied. The control eye received nonfunctioning adenoviral vector. After 2, 5, 7, and 30 days the eyes were processed for histological or immunohistochemical examination to evaluate wound healing of conjunctiva. The expressions of type-I collagen and growth factors were evaluated by real time-reverse transcriptase-polymerase chain reaction. The effects of Smad7 gene introduction on the cultured human SCFs were also studied.


RESULTS
Marked Smad7 protein expression was detected in the vector-treated conjunctival epithelium and fibroblasts that coincided with green fluorescein protein expression, whereas faint endogenous Smad7 expression was observed in the control tissue. In vivo Smad7 gene introduction blocked Smad2/3 nuclear translocation with suppression of alpha-smooth muscle actin (alphaSMA) and vascular endothelial growth factor (VEGF) in fibroblasts and invasion of macrophages. Smad7 gene transfer suppressed mRNA expressions of connective tissue growth factor (CTGF), VEGF, and monocyte chemoattractant protein-1 in vivo and those of type-I collagen, alphaSMA, and CTGF in vitro.


CONCLUSIONS
Smad7 gene transfer modulates injury-induced wound healing of conjunctival tissue in mice, suggesting that this strategy may be effective in preventing excessive scarring following filtration surgery. The mechanism might include suppression of activation of fibroblasts and reduction of macrophage invasion.
Yamanaka
Osamu
O
Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan. yamanaka@wakayama-med.ac.jp
Ikeda
Kazuo
K
Saika
Shizuya
S
Miyazaki
Ken-ichi
K
Ooshima
Akira
A
Ohnishi
Yoshitaka
Y
D000199:Actins / Q000037:antagonists & inhibitors; D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics; D024042:Collagen Type I / Q000235:genetics; D003228:Conjunctiva / Q000166:cytology / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D055513:Connective Tissue Growth Factor; D005131:Eye Injuries / Q000378:metabolism / Q000503:physiopathology*; D005347:Fibroblasts / Q000378:metabolism; D018014:Gene Transfer Techniques; D049452:Green Fluorescent Proteins; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D049408:Luminescent Agents; D051379:Mice; D008810:Mice, Inbred C57BL; D009130:Muscle, Smooth / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors; D051906:Smad7 Protein / Q000235:genetics* / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000235:genetics; D014945:Wound Healing
D000199:Actins; C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D024042:Collagen Type I; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D049408:Luminescent Agents; D012333:RNA, Messenger; D051906:Smad7 Protein; D042461:Vascular Endothelial Growth Factor A; D055513:Connective Tissue Growth Factor; D049452:Green Fluorescent Proteins