Purpose: Macular edema resulting from retinal vascular leakage is the leading cause of vision loss in diabetic retinopathy (DR) . The nuclear factor of activated T-cells (NFAT) family of transcription factors is known to upregulate inflammatory cytokines in response to high glucose. This study explored the effect of NFAT inhibition on retinal vascular leakage and inflammation in DR in vivo and in vitro.
Methods: The streptozocin-induced (STZ) model was used as the mouse model of diabetic retinopathy. Hyperglycemia was induced at 4 weeks in C57BL/6J mice and confirmed when fasting plasma glucose became persistently elevated (>300 mg/dL) . Experiments were performed at weeks of hyperglycemia. STZ mice were injected intravitreally with the NFAT signaling inhibitor INCA-6 (25 uM) or vehicle (0.1% DMSO in PBS) . Uninjected eyes of both STZ and control mice served as additional controls. Evans blue dye (EBD) was used to measure retinal vascular leakage. Primary mouse retinal microvascular endothelial cells (MRMECs) were used for in vitro experiments. MRMEC monolayers were treated with INCA-6 (2.5 uM) or with vehicle and cell permeability was induced with mouse VEGF165. The transendothelial electrical resistance (TEER) was measured with the electrical cell-substrate impedance sensing method. MRMEC IL-6 production was investigated by ELISA.
Results: In the STZ model of diabetic retinopathy, EBD vascular leakage was significantly reduced in INCA-6-treated eyes (INCA-6: 0.85 ± 0.57, n=5; vehicle: 1.78 ± 0.38, n= 7; P=0.007) , and in INCA-6 treated eyes compared to untreated eyes (untreated: 2.83 ± 1.63, n=4, P=0.04) . In the VEGF-induced MRMEC monolayer permeability model, INCA-6 significantly preserved TEER compared to vehicle (n=12, P<0.05) and decreased the VEGF-induced production of IL-6 (n=5, P<0.05) .
Conclusions: NFAT inhibition has therapeutic potential to prevent and treat retinal vascular leakage and inflammation in DR.
I.De la huerta: None. J.L.Nunez: None. J.M.Poloway: None. V.Reddy: None. J.Penn: None.
National Institutes of Health (EY032620) International Retinal Research Foundation Grant Knights Templar Foundation Career Starter Grant