Abstract
Purpose :
To investigate the role of bile acid metabolite, taurocholic acid (TCA), as an inhibitor of the development and progression of age-related macular degeneration (AMD) modeled in vitro.
Methods :
ARPE-19 cells were treated with 300 µM paraquat or paraquat with different concentrations of taurocholic acid (TCA) (10, 50, 100, 200, 500 µM) for 48 hours. ARPE-19 cells tight junctions were evaluated by measuring transepithelial electrical resistance (TEER) and using immunofluorescence for imaging investigating ZO-1. Macaque RF/6A choroidal endothelial cells were treated with 100ng/mL vascular endothelial growth factor (VEGF) or 100 ng/mL VEGF with different concentrations of TCA (10, 50, 100, 200, 500 µM) for 24 hours. The effects of neovascularization of RF/6A cells in vitro were evaluated using BrdU proliferation assay, scratch-wound migration assay, and tube formation assay.
Results :
In the TEER assay, ARPE-19 cells treated with paraquat and either: 10 µM TCA had a 50% recovery in functional tight junctions, 50 µM TCA had a significant 80% recovery in functional tight junctions (p<0.006), and complete recovery for functional tight junctions for 100 (p<0.01), 200 (p<0.01), and 500 (p<0.009) µM TCA. In the studies looking at ZO-1 immunofluorescence after paraquat exposure, TCA treatment demonstrated a dose-dependent recovery of ZO-1 organization. In the proliferation assay with RF/6a cells, there was no significant reduction in cell proliferation with TCA treatment. In the scratch migration assay there was a significant reduction of 35% (p<0.006), 40% (p<0.004) and 39% (p<0.008) with 100, 200 and 500 μM TCA treatments respectively. In the tube formation assay there was a significant 31% (p<0.003) and 42% (p<0.003) reduction in tube formation with 200 μM and 500 μM TCA.
Conclusions :
The bile acid metabolite TCA demonstrated a preservation of tight junctions in RPE cells, and inhibition of choroidal endothelial cell migration and tube formation in a dose-dependent manner in vitro modeling improvement in RPE function and reduction in potential neovascularization in AMD. If bile acids affect both RPE health and survival as well as endothelial pathology within AMD, this could potentially be a synergistic pathway for therapeutic targets.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.