Inhibition of HDAC1 and 3 in the Presence of Systemic Inflammation Reduces Retinal Degeneration in a Model of Dry Age-Related Macular Degeneration.

Purpose: Previously, we identified increased retinal degeneration and cytokine response in a mouse model of dry age-related macular degeneration (AMD) in the presence of systemic inflammation from rheumatoid arthritis (RA). Histone deacetylases (HDACs) regulate cytokine production by reducing acetylation and are found to be dysregulated in inflammatory diseases, including RA and AMD. Therefore, this current study investigates the effect of HDAC inhibition on AMD progression in the presence of systemic inflammation. Methods: Collagen induced arthritis (CIA) was induced in C57BL6J mice, followed by sodium iodate (NaIO₃)-induced retinal degeneration. Mice were treated with a selective HDAC class I inhibitor, MS-275, and retinal structure [optical coherence tomography (OCT)], function (electroretinography), and molecular changes quantitative real-time polymerase chain reaction (RT-qPCR, Western Blot) were assessed. Results: NaIO₃ retinal damage was diminished in CIA mice treated with MS-275 (P ≤ 0.05). While no significant difference was observed in retinal pigment epithelium (RPE) function, a trend in increased c-wave amplitude was detected in CIA + NaIO₃ mice treated with MS-275. Finally, we identified decreased Hdac1, Hdac3, and Cxcl9 expression in CIA + NaIO₃ mouse RPE/choroid when treated with MS-275 (P ≤ 0.05). Conclusions: Our data demonstrate that HDAC inhibition can reduce the additive effect of NaIO₃-induced retinal degeneration in the presence of systemic inflammation by CIA as measured by OCT analysis. In addition, HDAC inhibition in CIA + NaIO₃ treated mice resulted in reduced cytokine production. These findings are highly innovative and provide additional support to the therapeutic potential of HDAC inhibitors for dry AMD treatment.