Neutralization of IL-23 depresses experimental ocular neovascularization

Interleukin-23 (IL-23) is a heterodimeric cytokine that consists of p19, a novel subunit, and p40, which is shared by IL-12. IL-23 has been demonstrated to play an important role in autoimmunity and tumor growth. However, the role of IL-23 in ocular neovascularization (NV) diseases remains unclear. In this study, we explored the role of IL-23 in the processing of retinal and choroidal neovascularization (RNV and CNV). We found a significantly higher expression of IL-23 in the retinas with oxygen-induced retinopathy (OIR), and after neutralizing IL-23, the mRNA and protein levels of the angiogenic factors vascular endothelial growth factor receptor (VEGFR)1/FLT-1, VEGFR2/FLK-1, placental growth factor (PIGF), endothelial-specific receptor tyrosine kinase (Tie2), inducible nitric-oxide synthase (iNOS), matrix metalloproteinase (MMP) 2 and MMP9 were significantly down regulated, while the opposite trend was found for the anti-angiogenic molecules chemokine (C-X-C motif) ligand (CXCL) 9 and CXCL10. IL-23 blockade caused less NV in both the RNV and CNV mouse models. In addition, our in vitro assay showed that IL-23 alone is able to increase the ability of endothelial cells to form tubes. Our findings suggest that targeting IL-23 could be a potential therapy for RNV and CNV diseases.