Abstract
Purpose :
Dry Eye Syndrome (DES) is a debilitating disease affecting up to 30% of the over-50s population. Although disease pathogenesis is multifactorial, inflammatory mechanisms are a key driver of DES symptoms (burning, irritation, redness) in most patients with moderate-to-severe disease. Treatment options for these patients are limited, with topical cyclosporine and Lifitegrast being the only FDA-approved therapeutics. Here we investigate the potential of NSKIs as a treatment for DES and demonstrate that the kinases targeted are up-regulated in conjunctival cells of patients compared to healthy controls (HCs).
Methods :
Inhibitory kinase activity of the NSKI TOP1362 was assessed in competition binding assays, with determination of dissociation constants (Kd, KinomeScanTM) for P-38 alpha (P38-α) and spleen tyrosine kinase (Syk), and inhibition of substrate phosphorylation (ZLYTETM) for Src activity. Human conjunctival cells from DES patients (n=9) and HCs (n=8) were harvested by impression cytology using the Eyeprim™ device. Following morphological assessment, quantitative polymerase chain reaction (qPCR) was performed to quantify differences in expression of P38-α, Src kinase and Syk. In addition, the effects of TOP1362 (0.01 – 1 µg/ml) on p38-α expression in Chang cells challenged with 100mM NaCl for 6 hours, was assessed.
Results :
TOP1362 is a potent inhibitor of P38-α and Syk kinases with Kd values of 26 and 18nM, respectively and an IC50 of 14 nM in the Src kinase activity assay. Using the Eyeprim device, the average yield of human conjunctival cells was 1.1 x105cells/mm2. qPCR analysis demonstrated significant up-regulation of Syk (P<0.0001), P38-a (P<0.001) and Src (P<0.001) in conjunctival cells isolated from DES patients compared to HCs. Hyperosmolar challenge of Chang cells with NaCl led to a statistically significant increase in P38-α expression. TOP1362 dose-dependently inhibited this up-regulation.
Conclusions :
TOP1362 potently inhibits P38-α, Src and Syk; key kinases involved in inflammatory signalling cascades. Here, we demonstrate that these kinases are significantly up-regulated in conjunctival cells of DES patients compared to HCs, demonstrating the potential utility of NSKIs as a treatment option for this debilitating disease.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.