Title: ADAM17 Inhibitors Attenuate Corneal Epithelial Detachment Induced by Mustard Exposure.

Authors: DeSantis-Rodrigues, Andrea; Chang, Yoke-Chen; Hahn, Rita A; Po, Iris P; Zhou, Peihong; Lacey, C Jeffrey; Pillai, Abhilash; C Young, Sherri; Flowers 2nd, Robert A; Gallo, Michael A; Laskin, Jeffrey D; Gerecke, Donald R; Svoboda, Kathy K H; Heindel, Ned D; Gordon, Marion K

Published In Invest Ophthalmol Vis Sci, (2016 Apr)

Abstract: PURPOSE: Sulfur mustard, nitrogen mustard (NM), and 2-chloroethyl ethyl sulfide all cause corneal injury with epithelial-stromal separation, differing only by degree. Injury can resolve in a few weeks or develop into chronic corneal problems. These vesicants induce microbullae at the epithelial-stromal junction, which is partially caused by cleavage of transmembranous hemidesmosomal collagen XVII, a component anchoring the epithelium to the stroma. ADAM17 is an enzyme involved in wound healing and is able to cleave collagen XVII. The activity of ADAM17 was inhibited in vesicant-exposed corneas by four different hydroxamates, to evaluate their therapeutic potential when applied 2 hours after exposure, thereby allowing ADAM17 to perform its early steps in wound healing. METHODS: Rabbit corneal organ cultures exposed to NM for 2 hours were washed, then incubated at 37°C for 22 hours, with or without one of the four hydroxamates (dose range, 0.3-100 nmol in 20 μL, applied four times). Corneas were analyzed by light and immunofluorescence microscopy, and ADAM17 activity assays. RESULTS: Nitrogen mustard-induced corneal injury showed significant activation of ADAM17 levels accompanying epithelial-stromal detachment. Corneas treated with hydroxamates starting 2 hours post exposure showed a dose-dependent ADAM17 activity inhibition up to concentrations of 3 nmol. Of the four hydroxamates, NDH4417 (N-octyl-N-hydroxy-2-[4-hydroxy-3-methoxyphenyl] acetamide) was most effective for inhibiting ADAM17 and retaining epithelial-stromal attachment. CONCLUSIONS: Mustard exposure leads to corneal epithelial sloughing caused, in part, by the activation of ADAM17 at the epithelial-stromal junction. Select hydroxamate compounds applied 2 hours after NM exposure mitigated epithelial-stromal separation.

PubMed ID: 27058125

MeSH Terms: ADAM Proteins/metabolism*; ADAM17 Protein; Animals; Blotting, Western; Cells, Cultured; Corneal Diseases/chemically induced; Corneal Diseases/metabolism*; Corneal Diseases/pathology; Corneal Stroma/drug effects; Corneal Stroma/metabolism; Corneal Stroma/pathology; Epithelium, Corneal/drug effects; Epithelium, Corneal/metabolism*; Epithelium, Corneal/pathology; Humans; Mechlorethamine/toxicity*; Rabbits; Tomography, Optical Coherence; Tumor Necrosis Factor-alpha