Factors regulating capillary remodeling in a reversible model of inflammatory corneal angiogenesis

Abstract

Newly formed microcapillary networks arising in adult organisms by angiogenic and inflammatory stimuli contribute to pathologies such as corneal and retinal blindness, tumor growth, and metastasis. Therapeutic inhibition of pathologic angiogenesis has focused on targeting the VEGF pathway, while comparatively little attention has been given to remodeling of the new microcapillaries into a stabilized, functional, and persistent vascular network. Here, we used a novel reversible model of inflammatory angiogenesis in the rat cornea to investigate endogenous factors rapidly invoked to remodel, normalize and regress microcapillaries as part of the natural response to regain corneal avascularity. Rapid reversal of an inflammatory angiogenic stimulus suppressed granulocytic activity, enhanced recruitment of remodelling macrophages, induced capillary intussusception, and enriched pathways and processes involving immune cells, chemokines, morphogenesis, axonal guidance, and cell motility, adhesion, and cytoskeletal functions. Whole transcriptome gene expression analysis revealed suppression of numerous inflammatory and angiogenic factors and enhancement of endogenous inhibitors. Many of the identified genes function independently of VEGF and represent potentially new targets for molecular control of the critical process of microvascular remodeling and regression in the cornea.

A microarray whole-genome gene expression dataset in a rat model of inflammatory corneal angiogenesis

“…The fold change expression profile between suture IN and suture OUT as determined by qPCR in general was in agreement with the expression profile determined by the microarray analysis Fig. 4a,b, with further qPCR results available 19 .…”

“…The morphological data was analysed for changes in neovessels (for example vessel density and splitting), and for the dynamics of the infiltrating inflammatory cells. From this data, we confirmed the induction of a remodelling phenotype following the removal of the angiogenic stimulus 19 . These findings were of importance as they served as a foundation for the design and planning of the microarray experiments that followed, and whose dataset we now describe here.…”

“…Ethical application, strain and housing conditions of the animals used for this study were previously detailed 19 . Using 12–16 weeks old rats, the suture model of inflammatory corneal neovascularisation was used as previously described 21 .…”

“…In both suture IN and suture OUT arms, only the vascularised area of the tissue was excised and immediately immersed in RNA later and stored at −20 °C. For each of the four groups (i.e., Control, 0 h, 24 h suture IN, 24 h suture OUT), n =4 rats were used, and the identical phenotype was confirmed by in vivo slit lamp and IVCM imaging at 0 h. A detailed graphical illustration of the experimental design we followed was previously published 19 .…”

“…In addition, the data files described here were previously analyzed in-depth, and it was shown that suture removal induced blood vessel remodelling, and that many genes classified as either pro-angiogenic/pro-inflammatory or anti-angiogenic/pro-maturation were identified. At the phenotypic level, blood vessel remodelling was characterized by an increase in macrophages, and a reduction of granulocytes in the cornea 19 .…”