(544.7) Early Interventions for Toxicant Ocular Injury May Need to be Toxicant-Specific

Poster Board Number: B183

Albert Ruff (USAMRICD), John Lehman (USAMRICD), Robert Causey (USAMRICD), Christina LaGrasta (USAMRICD), Amber Gomez (USAMRICD), Jeffrey Koenig (USAMRICD)

Corneal injuries induced by various toxicants share similar pathologies such as corneal opacity and neovascularization. Several studies suggest that the molecular mechanisms that drive these delayed and progressive pathologies may converge at later time points. However, chemicals with different toxicological properties are likely to elicit different molecular responses early after exposure. These early responses may present opportunities for therapeutic intervention. Our objective was to study the molecular mechanisms of toxicant-induced corneal injury, utilizing siRNA high throughput screening (HTS). Our hypothesis was that early molecular responses to each toxicant would be dissimilar and targets validated in vitro may be effective for treating toxicant injury. We selected ~3000 targets from preconfigured Dharmacon Human Druggable libraries for three toxicants: chloropicrin (CP), hydrogen fluoride (HF), and sulfur mustard (HD). Microarray data from injured mouse corneas were used to focus library selection. Screening was conducted in the human immortalized corneal epithelial cell line SV40-HCEC. Endpoints included IL-8 levels in cell culture supernatants and cell viability. Target validation studies utilized phenotype restoration in SV40-HCEC and siRNA function in the human immortalized corneal epithelial cell line, TCEpi. Validation endpoints included multiplex cytokine analysis and high content analysis to understand toxicant effect and target function. Approximately 20 target genes entered in vitro validation studies for each toxicant, but only one gene was in common, NR3C1, a glucocorticoid receptor. For each toxicant, 5-10 target genes entered testing in mice. These results demonstrated that the drug chlorpheniramine (target HRH1) was effective in preventing central progression of corneal neovascularization in CP-induced corneal injury during 8 weeks of study even after treatment was withdrawn 2 weeks post-exposure. In conclusion, these findings show that there is little similarity in the early molecular responses to these three toxicants and suggest that some early interventions for toxicant ocular injury may need to be toxicant-specific.

Support or Funding Information

This research was supported by an interagency agreement between NIH/NIAID and the USAMRICD, and in part by an appointment to the Postgraduate Research Participation Program at the U.S. Army Medical Research Institute of Chemical Defense administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and USAMRDC.