Abstract
Purpose :
Soluble epoxide hydrolase (sEH) metabolizes pro-resolving epoxy fatty acids into diols. sEH is a potential therapeutic target for choroidal neovascularization (CNV) in wet age-related macular degeneration (AMD) and other eye diseases. Localization of sEH in the retina is contentious and cross-interpretation among different studies is complicated due to antibody limitations. This study aimed to define the localization of sEH through co-staining with retinal cell type markers and RNAscope in situ hybridization in human AMD and control eyes, and in mouse eyes with and without laser-induced CNV.
Methods :
Paraffin sections of eyes from anonymized human wet AMD and control subjects were obtained from the National Disease Research Interchange. 7-week old C57BL/6J mice underwent laser-induced CNV and on day 3 post laser, enucleated eyes were fixed and cryosectioned. Coimmunostaining was done for sEH, retinal pigment epithelium (RPE), and photoreceptor markers. RNAscope was performed using target specific probes for EPHX2 (encoding sEH) and images were acquired by confocal microscopy.
Results :
Costaining of sEH with cell type markers revealed that sEH is overexpressed in photoreceptors and RPE cells in areas with degenerative changes. By RNAscope, EPHX2 mRNA was also highly expressed in the pathological conditions compared to controls. EPHX2 mRNA was seen in the inner nuclear layer, outer nuclear layer and RPE of the normal and diseased human and mouse retina.
Conclusions :
Previous data showed sEH expression in vasculature, Müller glia, and inner and outer segments of photoreceptors. Here, we also revealed sEH protein and mRNA expression in the RPE. Overexpression of sEH at the protein and mRNA level in CNV and disease-relevant cell types indicates a functional role of sEH in AMD pathophysiology and provides a context to target these cell types for developing pharmacotherapies.
This is a 2021 ARVO Annual Meeting abstract.