Abstract
Purpose :
Diabetic macular edema (DME) is a sight-threatening comorbidity of diabetes in patients with diabetic retinopathy. Loss of retinal pigment epithelium (RPE) integrity is one of the major contributing factors to DME. Here, we evaluated the role of a new generation of epigenetic modifiers, ITF2357 in regulating outer blood-retinal barrier function and investigated the underlying mechanism of action in protecting RPE integrity.
Methods :
ARPE-19, a human retinal pigment epithelial cells were treated with ITF2357 in the presence and absence of TNFα. Toxicity was evaluated using cellZScope, PrestoBlue, MTT and TUNEL assay. Tight junction integrity was measured via transepithelial electrical resistance (TEER) and paracellular diffusion, while junctional proteins were visualized by immunostaining and western blots. Regulation of the NF-κB pathway was examined during transient (30min) and persistent (24h) timepoints, in the presence of IKK inhibitor (BAY 11-7082).
Results :
ITF2357 was safe and prevented epithelial permeability by preserving tight junction (ZO-1 and occludin) and adherens junction (E-cadherin) protein expression post-TNFα treatment. ITF2357 was most effective at 24h attenuating IKK, IκBα, and p65 phosphorylation and ameliorated the expression of IL-1β, IL-6, MCP-1, and TNFα. ITF2357 delayed IκBα synthesis and turnover.
Conclusions :
ITF2357 protects RPE cellular integrity by regulating the turnover of tight and adherens junction proteins and modulating the NF-κB signaling pathway in the presence of an inflammatory stressor, suggesting targeting epigenetic modifiers in the treatment of DME.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.