Abstract
Purpose :
The highly selective and impermeable blood-retinal barrier is disrupted in ocular inflammatory diseases resulting in pathological vascular permeability. Alterations in expression and distribution pattern of cellular adherens junctions (AJs) and tight junctions (TJs) can contribute to barrier disruption. β-catenin (β-cat) is an integral component of AJs. ICG001 is a nuclear β-cat signaling inhibitor. By inhibiting β-cat nuclear transcription, ICG001 directs unbound β-cat to AJs and thereby promotes junctional stability. We investigated impact of ICG001 on retinal vascular leakage and inflammation in endotoxin-induced uveitis (EIU) model.
Methods :
EIU was induced in mice (8-10 weeks old, C57BL/6J) by a single intraperitoneal (i.p.) injection of LPS (5mg/Kg). ICG001 (5mg/Kg) was given i.p., an hour prior to LPS. Control mice received either vehicle or ICG001. Following treatments, at 24 and 48 h, mice were perfused, and samples were prepared for immunostaining and qRT-PCR studies. Vascular permeability was evaluated by immunostaining of extravasated albumin and changes in microglia/macrophage was assessed using Iba1 and F4/80 markers. Human retinal endothelial cells (HRECs) were treated with LPS (0.1µg/mL), ICG001(10µM) or both for 24 h. ICG001 impact on monolayer barrier resistance and β-cat distribution was determined using electric cell impedance sensing (ECIS) and immunostaining, respectively. Statistical analysis was performed using one-way ANOVA followed by the Tukey test.
Results :
LPS significantly increased albumin extravasation from retinal vessels at 24 h, which was ameliorated by ICG001 treatment (N=6-8/group, P<0.05). ICG001 significantly reduced the increase in microglia/macrophages with activated morphology, seen at 24 h (N=6-8/group, P<0.05) and 48 h (N=4/group, P<0.05) with LPS. While LPS induced upregulation of inflammatory cytokines (TNF-α, MCP-1, and IL-12), ICG001 treatment reduced inflammatory surge (N=3-4/group, P< 0.05). LPS disrupted HRECs β-cat distribution in AJs and reduced barrier resistance in-vitro, ICG001 treatment improved both (N=3-4, P<0.01).
Conclusions :
Use of ICG001 may greatly benefit compromised barrier integrity in ocular inflammatory diseases. Alteration of β-catenin distribution could serve as a novel cellular mechanism to tackle pathological retinal vascular permeability.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.