Comparative Proteomic Approach Implies Prohibitin as an Early Apoptotic Marker in the Retina

Abstract

Purpose: : To investigate early apoptotic signaling events in oxidative stress in the eye, comparative proteomics is used to find biomarkers in the retina and the retinal pigment epithelium (RPE) in various stress conditions. We uncovered that prohibitin is one of the early markers in oxidative stress in the retina and the RPE.

Methods: : Functional proteomic tools such as 2-dimensional differential gel electrophoresis (DIGE) using fluorescent probe and MALDI-TOF-TOF mass spectrometry have been used to study proteome changes in oxidative stress in the retina and the RPE. Functional role of prohibitin in the retina and the RPE were further studied using various biochemical methods such as immunohistochemitstry, Western blot, immunoprecipitation, and mass spectrometry.

Results: : Prohibitin has been known as a tumor suppressor that binds with p53 and E2F to inhibit cell proliferation. Here we show that mitochondrial prohibitin is down-regulated in oxidative stress in the retina. However, this down-regulation is diminished in the RPE. However, in vivo model of a tumor induced model as a positive control, prohibitin is up-regulated. Western blot analysis and immunohistochemistry indicated that prohibitin is overexpressed in Ganglion cells, photoreceptor cells and RPE cells.

Keywords: retina • retinal pigment epithelium • retinal degenerations: cell biology