Purchase this article with an account.
Elsayed Elbasiony, Sharad Mittal, Wonkyung Cho, Sunil Chauhan; Epithelium-derived interleukin-33 initiates mast cell-mediated corneal inflammation. Invest. Ophthalmol. Vis. Sci. 2020;61(7):463.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We have previously reported that injury-mediated activation of mast cells initiate corneal inflammation. In the present study, we sought to delineate the underlying mechanisms of mast cell activation following corneal injury that lead to neutrophil infiltration.
Potential mast cell activating factors (Interleukin (IL) 33, IL1β, IL6, SDF1α and Substance P) were used to stimulate mast cells for 3h. Mast cell activation markers β-tryptase and β-hexosaminidase and CXCL2 levels were evaluated in cultures using ELISA. Corneas were injured by removing the epithelium and anterior stroma with an Algerbrush II. IL33 levels were evaluated in tear wash of injured mice, as well as in epithelial and stromal lysates using ELISA. Infiltration of CD11b+Ly6G+ neutrophils (Median Fluorescent Intensity) was assessed in harvested corneas at 6h post-injury by flow cytometry. 2% Cromolyn or 1 mg/ml of IL33 neutralizing antibody were locally administered for in vivo mast cell inhibition.
Significant mast cell activation and CXCL2 secretion were observed following IL33 stimulation, compared to other inflammatory factor. ELISA analysis showed higher levels of IL33 in (i) tear wash of injured mice compared to naive controls and (ii) epithelium compared to stroma (117.6 ± 5.8 vs. 28.5 ± 5.4 ng/ml; p<0.01). Corneal injury resulted in significantly increased levels of β-tryptase and β-hexosaminidase in tear wash (β-tryptase: 76.5 ± 19 vs. 14.3 ± 1.5 ng/ml; p<0.01 and β-hexosaminidase: 0.13 ± 0.001 vs. 0.05 ± 0.001 unit/ml; p<0.001) and higher frequencies of neutrophils at 6h post-injury, relative to naive corneas (4.6 ± 0.3% vs. 1.1 ± 0.2%; p<0.001). Topical blockade of IL33 significantly inhibited mast cell activation (β-tryptase: 19.2 ± 0.2 vs. 43.4 ± 8.7 ng/ml; p<0.01) and reduced early infiltration of neutrophils to the injured cornea, relative to control groups (1.6 ± 0.1% vs. 4.5 ± 0.6%; p<0.01).
Our data demonstrate that damaged corneal epithelial cells release pre-stored IL33, which activates mast cells to secrete CXCL2 initiating early neutrophil recruitment.
This is a 2020 ARVO Annual Meeting abstract.
This PDF is available to Subscribers Only