HDAC Inhibition Prevents Primary Cone Degeneration Even After the Onset of Degeneration

Cone photoreceptor loss is the main cause of color blindness and loss of visual acuity in patients suffering from inherited cone dystrophies. Despite the crucial role of cones in everyday life, knowledge on mechanisms of cone cell death and the identification of potential targets for the preservation or delay of cone loss are scarce. Recent findings have shown that excessive histone deacetylase (HDAC) activity is associated with both primary rod and primary cone degeneration. Importantly, pharmacological inhibition of HDAC activity in vivo at the onset of cone degeneration offers a prolonged protection of cones in a mouse model of inherited cone degeneration (cpfl1). In this study, we evaluated the potential of trichostatin A (TSA), a pan-HDAC inhibitor, to prevent cone cell death at a later stage of degeneration in the cpfl1 model. We demonstrate that a single intravitreal TSA injection protected the cpfl1 cones even when administered after the onset of degeneration. In addition, the TSA treatment significantly improved aberrant cone nucleokinesis present in the cpfl1 retina. These results highlight the feasibility of targeted cone neuroprotection in vivo even at later disease stages of inherited cone dystrophies.