Document Type

Article

Publication Date

2013

Abstract

This study examined the effects of BMP7 gene transfer on corneal wound healing and fibrosis inhibition in vivo using a rabbit model. Corneal haze in rabbits was produced with the excimer laser performing -9 diopters photorefractive keratectomy. BMP7 gene was introduced into rabbit keratocytes by polyethylimine-conjugated gold nanoparticles (PEI2- GNPs) transfection solution single 5-minute topical application on the eye. Corneal haze and ocular health in live animals was gauged with stereo- and slit-lamp biomicroscopy. The levels of fibrosis [a-smooth muscle actin (aSMA), F-actin and fibronectin], immune reaction (CD11b and F4/80), keratocyte apoptosis (TUNEL), calcification (alizarin red, vonKossa and osteocalcin), and delivered-BMP7 gene expression in corneal tissues were quantified with immunofluorescence, western blotting and/or real-time PCR. Human corneal fibroblasts (HCF) and in vitro experiments were used to characterize the molecular mechanism mediating BMP7’s anti-fibrosis effects. PEI2-GNPs showed substantial BMP7 gene delivery into rabbit keratocytes in vivo (26104 gene copies/ug DNA). Localized BMP7 gene therapy showed a significant corneal haze decrease (1.6860.31 compared to 3.260.43 in control corneas; p,0.05) in Fantes grading scale. Immunostaining and immunoblot analyses detected significantly reduced levels of aSMA (4665% p,0.001) and fibronectin proteins (4865% p,0.01). TUNEL, CD11b, and F4/80 assays revealed that BMP7 gene therapy is nonimmunogenic and nontoxic for the cornea. Furthermore, alizarin red, vonKossa and osteocalcin analyses revealed that localized PEI2-GNP-mediated BMP7 gene transfer in rabbit cornea does not cause calcification or osteoblast recruitment. Immunofluorescence of BMP7-transefected HCFs showed significantly increased pSmad-1/5/8 nuclear localization (.88%; p,0.0001), and immunoblotting of BMP7-transefected HCFs grown in the presence of TGFb demonstrated significantly enhanced pSmad-1/5/8 (95%; p,0.001) and Smad6 (53%, p,0.001), and decreased aSMA (78%; p,0.001) protein levels. These results suggest that localized BMP7 gene delivery in rabbit cornea modulates wound healing and inhibits fibrosis in vivo by counter balancing TGFb1-mediated profibrotic Smad signaling.

Comments

This article was originally published in PLoS ONE, volume 8, issue 6, in 2013. DOI: 10.1371/journal.pone.0066434

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This work is licensed under a Creative Commons Attribution 4.0 License.

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