The functional role of decorin in corneal neovascularization in vivo. (June 2021)

• Record Type: Journal Article
• Authors: Balne, Praveen K.; Gupta, Suneel; Zhang, Jinjin; Bristow, Daniel; Faubion, Matthew; Heil, Sally D.; Sinha, Prashant R.; Green, Sydney L.; Iozzo, Renato V.; Mohan, Rajiv R.
• Is Part Of: Experimental eye research. Volume 207(2021)
• Publication Date: 2021-06
• Subjects: Decorin -- Cornea -- Corneal neovascularization -- Gene therapy -- Pro-angiogenic factors -- Anti-angiogenic factors; Ophthalmology -- Periodicals; Eye -- Periodicals; Œil -- Périodiques; Ophthalmology; Periodicals; Electronic journals; 612.8405
• DOI: 10.1016/j.exer.2021.108610
• Languages: English
• ISSNs: 0014-4835

Abstract

Abstract: Our earlier decorin ( Dcn ) gene overexpression studies found that the targeted Dcn gene transfer into the cornea inhibited corneal angiogenesis in vivo using a rabbit model. In this study, we tested the hypothesis that anti-angiogenic effects of decorin in the cornea are mediated by alterations in a normal physiologic balance of pro- and anti-angiogenic factors using decorin deficient ( Dcn −/− ) and wild type ( Dcn +/+ ) mice. Corneal neovascularization (CNV) in Dcn −/− and Dcn +/+ mice was produced with a standard chemical injury technique. The clinical progression of CNV in mice was monitored with stereo- and slit-lamp microscopes, and histopathological hematoxylin and eosin (H&E) staining. Protein and mRNA expression of pro- and anti-angiogenic factors in the cornea were evaluated using immunofluorescence and quantitative real-time PCR, respectively. Slit-lamp clinical eye examinations revealed significantly more CNV in Dcn −/- mice than the Dcn +/+ mice post-injury ( p < 0.05) and AAV5- Dcn gene therapy significantly reduced CNV in Dcn −/- mice compered to no AAV5- Dcn gene therapy controls ( p < 0.001). H&E-stained corneal sections exhibited morphology with several neovessels in injured corneas of the Dcn −/− mice than the Dcn +/+ mice. Immunofluorescence of corneal sections displayed significantly higher expression of α-smooth muscle actin ( α-SMA ) and endoglin proteins in Dcn −/- mice than Dcn +/+ mice ( p < 0.05). Quantitative real-time PCR found significantly increased mRNA levels of pro-angiogenic factors endoglin (2.53-fold; p < 0.05), Vegf (2.47-fold; p < 0.05), and Pecam (2.14-fold; p < 0.05) and anti-angiogenic factor Vegfr2 (1.56-fold; p < 0.05) in the normal cornea of the Dcn −/− mice than the Dcn +/+ mice. Furthermore, neovascularized Dcn −/− mice corneas showed greater increase in mRNA expression of pro-angiogenic factors endoglin (4.58-fold; p < 0.0001), Vegf (4.16-fold; p < 0.0001), and Pdgf (2.15-fold; p < 0.0001) and reduced expression of anti-angiogenic factors Ang2 (0.12-fold; p < 0.05), Timp1 (0.22-fold; p < 0.05), and Vegfr2 (0.67-fold; p > 0.05) compared to neovascularized Dcn +/+ mice corneas. These gene deficience studies carried with transgenic Dcn −/− mice revealed decorin's role in influencing a physiologic balance between pro-and anti-angiogenic factors in the normal and injured cornea. We infer that the functional deletion of Dcn promotes irregular corneal repair and aggravates CNV. Highlights: Decorin acts as an anti-angiogenic molecule in the cornea. Decorin regulates bioavailability and activity of several angiogenic growth factors. Decorin maintains the homeostasis between the pro- and anti-angiogenic factors. Decorin deficient mice cornea is more susceptible to angiogenic stimuli.