Abstract
Purpose :
Recent studies in our Laboratory have demonstrated that a carbohydrate-binding protein, galectin-8 (Gal-8), plays an important role in the pathogenesis of Pseudomonas Aeruginosa (PA) keratitis. Using a mouse model of PA keratitis, we have shown that: (i) Gal-8 KO mice are resistant to PA keratitis, and that (ii) Gal-8 modulates innate immune response by dampening the TLR4 and inflammasome pathways. These data suggest that inhibiting Gal-8 may improve the outcome of the disease. Therefore, in an effort to find effective strategies to control the disease, the goal of the current study was to test the therapeutic potential of inhibitors of Gal-8 in PA keratitis
Methods :
Two groups of Wild type mice (7 – 10 weeks old) were anesthetized, the central corneas of mice were scarified with three parallel 1-mm incisions and a 5 μL drop containing 2000 CFU of bacterial strain PA 6077 was applied to the eye. Immediately prior to infection, control group received a subconjunctival injection of vehicle (10 μL of PBS + DMSO) and the experimental group received a subconjunctival injection of Gal-8 inhibitor, 19a (Hassan et al. Eur J Med Chem, 223:113664, 2021) (10 μL, 5 mg/mL in vehicle). The severity of bacterial keratitis was graded on post-infection day 1, and then corneas were harvested for bacterial enumeration. The experiment was repeated four times. Also, varying concentrations of the inhibitor were tested.
Results :
Galectin inhibitor, 19a, at 5 mg/ml concentration, substantially reduced opacity score (Vehicle: 2.7±0.12; 19a: 1.9±0.16; n=40, p<0.0002) and the bacterial load (Vehicle: 1.6x106; 19a: 0.6x106 n=40) compared to vehicle.
Conclusions :
Targeting Gal-8 is an attractive strategy for the development of novel treatment for blinding immunopathology resulting from bacterial keratitis and possibly other ocular disorders, such as corneal graft rejection and dry eye disease.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.