Purchase this article with an account.
Katie M Hudson, Min Zheng, Daniel J Carr; Neutralization of TNF-α significantly impairs corneal lymphangiogenesis in response to HSV-1 infection. Invest. Ophthalmol. Vis. Sci. 2014;55(13):857.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To characterize the impact of TNF-α on corneal lymphangiogenesis during acute HSV-1 infection.
Recombinant (r) VEGFA or TNF-α was injected into wild-type (WT) mouse corneas daily for 7 days. Following treatment, the corneas were evaluated via confocal microscopy for lymphatic vessel area (LYVE-1+) and the number of lymphatic vessel sprouts. TNFα deficient mice (TNF-α-/-), TNF-α receptor deficient mice (TNFR1-/- and TNFR2-/-) and WT mice were infected with 10^5 pfu/cornea of HSV-1 and processed 5 days post-infection (pi) for blood (CD31+) and lymphatic (LYVE-1+) vessels. HSV-1 infected WT mice were treated with neutralizing antibodies to TNF-α via subconjuctival injections. At 5 days pi, corneas were assessed for corneal lymphangiogenesis. Corneas from HSV-1 infected WT and TNF-α-/- mice were processed for analysis of 20 target genes associated with angiogenesis using Affymetrix quantigene assays. HSV-1 infected TNF-α-/- mice were treated with neutralizing IL-6 antibody and evaluated for corneal lymphangiogenesis and protein levels of pro-angiogenic factors via suspension array.
Administration of rVEGFA or rTNF-α led to a modest increase in the number of sprouts and LYVE-1+ vessel area, whereas a combined treatment of both VEGFA and TNF-α led to a significant increase in both the number of sprouts and lymphatic vessel area. Consistent with this observation, HSV-1 infected WT mice treated with neutralizing antibody to TNF-α showed a reduction in their lymphangiogenic response. However, infection of TNFα-/- mice with HSV-1 showed a similar lymphangiogenic response as HSV-1 infected WT mice, suggesting redundant pro-angiogenic compensatory factors may exist. To address this issue, we compared the gene expression levels of 20 growth factors, cytokines, and matrix metalloproteinases associated with angiogenesis. Of the factors assessed, IL-6, IL-1β, PDGF, and ANGPT2 were significantly elevated in the TNF-α-/- versus WT mouse corneas. The application of IL-6 neutralizing antibody to TNF-α-/- mice significantly impaired HSV-1-induced lymphangiogenesis in comparison to isotypic control treated mice, suggesting IL-6 to be a major compensatory cytokine that promotes lymphangiogenesis in the absence of TNF-α.
Our data indicates TNF-α can function as a pro-lymphangiogenic growth factor in the cornea under both non-inflammatory and inflammatory/infectious conditions.
This PDF is available to Subscribers Only