Peroxiredoxin 3 (PDRX3) is highly expressed in the primate retina especially in blue cones

Oxidative stress and loss of mitochondrial function have been implicated in age-related ocular diseases and thus studying enzymes involved in these processes may be of particular importance in these diseases. Peroxiredoxin III (PRDX3) is one of a family of six known peroxiredoxins which are known to protect cells against oxidative damage. PRDX3 is localized to the mitochondria and has been reported to be induced by hydrogen peroxide in aortic endothelial and lens epithelial cells. Using a highly specific commercially available antibody, PRDX3 was readily detected by immunoblot in monkey neural retina. Immunohistochemical analysis of human and monkey retina localized PRDX3 mainly to the photoreceptor inner segments, the outer and inner plexiform layers, and the ganglion cells. These are areas of known high mitochondrial content. In the monkey retina some of the cone inner segments were much more strongly labeled than others. Dual labeling experiments using specific anti-cone opsin antibodies determined that the high expressing cones were of the blue subtype. By contrast, in the human retina all of the cone inner segments were immunoreactive. This difference may be due to a postmortem induction of PRDX3 in the human sample. These results suggest that PRDX3 may be important in protecting photoreceptor mitochondria especially in blue cones.