Abstract
Purpose :
Alteration of the blood-retinal barrier is the hallmark of diabetic retinopathy that results in damage to cell junctional proteins ultimately leading to vision loss. Current anti-VEGF treatments are effective only in 33-45% patients with diabetic macular edema (DME). To overcome challenges associated with existing therapies, we used a previously approved, small molecule drug library to check the efficacy on the functionally promising candidate molecules.
Methods :
We used the Prestwick chemical library (PCL) consisting of off-patent compounds approved by FDA with diverse chemical and pharmacological characters, and well characterized bioavailability and safety information in humans. We performed a high throughput screening (HTS) assay platform to check the in vitro monolayer permeability in human retinal endothelial cells (HRECs) with the electrical cell substrate impedance sensing (ECIS) system. HRECs (approx. 8000 cells/well) were plated into fibronectin-coated 96-well plates and grown for 16 hours until maximum resistance was attained (1200 V). Human recombinant VEGF (50 ng/ml) was added to the wells along with each of 250 drug library compounds (10 uM). Changes in trans-endothelial electrical resistance were monitored for 24 hours. We used a cutoff range of > 75% viability using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay with concentration of 10 uM. Resistance values were normalized to the identical starting resistance value at time 0 and presented as normalized resistance versus time.
Results :
Several compounds showed toxicity and were eliminated from the trial. The ECIS assay identified 5 drugs that decreased in vitro permeability in VEGF treated HRECs. Five drugs, namely rufinamide, etofenamate, mexenone, melengestrol acetate, and sulfaquinoxaline sodium salt showed significantly increased resistance after the addition of VEGF compared to controls without drugs, while other drugs resulted in no change to mild change in resistance.
Conclusions :
In this study we have identified several drugs that can decrease in vitro permeability in human retinal endothelial cells. The identified chemical probes can be directly used for anti-diabetic retinopathy drug development or serve to discover novel disease targets for future drug discovery.
This is a 2021 ARVO Annual Meeting abstract.