Selective IKK2 inhibitor IMD0354 disrupts NF-κB signaling to suppress corneal inflammation and angiogenesis

Abstract

Corneal neovascularization is a sight-threatening condition caused by angiogenesis in the normally avascular cornea. Neovascularization of the cornea is often associated with an inflammatory response, thus targeting VEGF-A alone yields only a limited efficacy. The NF-κB signaling pathway plays important roles in inflammation and angiogenesis. Here, we study consequences of the inhibition of NF-κB activation through selective blockade of the IKK complex IκB kinase β (IKK2) using the compound IMD0354, focusing on the effects of inflammation and pathological angiogenesis in the cornea. In vitro, IMD0354 treatment diminished HUVEC migration and tube formation without an increase in cell death and arrested rat aortic ring sprouting. In HUVEC, the IMD0354 treatment caused a dose-dependent reduction in VEGF-A expression, suppressed TNFα-stimulated expression of chemokines CCL2 and CXCL5, and diminished actin filament fibers and cell filopodia formation. In developing zebrafish embryos, IMD0354 treatment reduced expression of Vegf-a and disrupted retinal angiogenesis. In inflammation-induced angiogenesis in the rat cornea, systemic selective IKK2 inhibition decreased inflammatory cell invasion, suppressed CCL2, CXCL5, Cxcr2, and TNF-α expression and exhibited anti-angiogenic effects such as reduced limbal vessel dilation, reduced VEGF-A expression and reduced angiogenic sprouting, without noticeable toxic effect. In summary, targeting NF-κB by selective IKK2 inhibition dampened the inflammatory and angiogenic responses in vivo by modulating the endothelial cell expression profile and motility, thus indicating an important role of NF-κB signaling in the development of pathologic corneal neovascularization.Electronic supplementary materialThe online version of this article (10.1007/s10456-018-9594-9) contains supplementary material, which is available to authorized users.

Repeat Corneal Neovascularization is Characterized by More Aggressive Inflammation and Vessel Invasion Than in the Initial Phase

“…To investigate these questions, and given the importance of inflammation as a driving force and modulator of corneal neovascularization, [20][21][22] we used a model of suture-induced inflammatory neovascularization in the rat cornea to investigate the process of repeat neovascularization after a spontaneous and incomplete regression. The analysis was conducted at the phenotypic, and gene expression level, comparing the second episode of neovascularization with the first, by longitudinal examinations conducted in the same corneas.…”

Pharmacological Inhibition of Caspase-8 Suppresses Inflammation-Induced Angiogenesis in the Cornea

“…Because the normal cornea lacks vessels and is convenient for experimental operation, it is an ideal system to investigate angiogenesis [27,28]. Furthermore, angiogenesis plays a key role in corneal disorders, such as corneal burn and virus infection [29][30][31].…”

Regulation of inflammation and angiogenesis in the cornea

“…The drawbacks of both steroids and anti-VEGF warrants the need for safer and more effective treatments. The search for alternative treatment approaches and targets 78,215,216,217,218 , and ways to circumvent resistance to treatment is underway. One of the hypothesized means of resistance to anti-VEGF treatment is by the rapid remodeling and maturation of capillaries, making them less susceptible to treatment.…”

“…Not surprisingly, LXRs are known to mediate anti-inflammatory properties 236,237,238,239,240 . LXRs mediate their antiinflammatory properties by transrepression of NF-κB-signaling 241,240,242 , a pathway known to be involved in corneal neovascularization 77,78,243 . It is probable that LXRs suppresses inflammation in the cornea through transrepression of NF-κB-signaling, as reported in other conditions 244 .…”

“…Neutrophils and monocytes secrete factors that lead to vasodilation and to recruitment of more inflammatory cells 76 . The recruited inflammatory cells express proinflammatory genes via activation of Nuclear Factor-κB (NfκB) pathway, to promote inflammation 77,78 .…”