Abstract
Purpose:
Inflammation caused by activated retinal microglia (RMG) has been demonstrated to play a pathogenic role in degenerative retinal diseases. Among other effectors, aldose reductase (AR) has been linked to ocular inflammation in the endotoxin-induced uveitis (EIU) model and diabetic retinopathy (DR). The purpose of this study is to investigate whether AR inhibition or genetic downregulation results in a decrease in inflammatory and angiogenic markers in RMG.
Methods:
Primary mouse RMG were isolated from wild type or AR knockout mice and identified by staining with the specific marker, Iba-1. Inflammatory cytokines secreted from macrophages or RMG were measured by ELISA assay. VEGF secretion from RMG was measured measured by ELISA after incubating cells under hypoxic conditions. Cell migration following endotoxin exposure was determined using a transwell assay. Active MMP-9 was detected by gelatin zymography. Apoptosis of ARPE-19 cells were conducted by co-cultured system and analyzed by flow cytometry with Annexin V stainig.
Results:
Fluorescence images identified the RMG by Iba-1 staining. Western blot showed that AR level in RMG is similar to macrophages and microglia cell lines. AR inhibition or ablation decreased LPS-induced cytokines secretion in macrophages and RMG, and reduced hypoxia-induced VEGF secretion in RMG. AR inhibition or ablation also attenuated LPS-induced cell migration. We further elucidated that AR inhibition or knockdown reduces activation of MMP-9. Additionally, AR inhibition or deficiency rescues activated RMG-induced apoptosis in ARPE-19 cells.
Conclusions:
These results suggest that AR inhibition may be useful as a therapeutic agent against retinal diseases by moderating RMG inflammatory and angiogenesis responses.
Keywords: 699 retinal glia •
746 uveitis-clinical/animal model •
499 diabetic retinopathy