Quantitative Proteomic Profiling Reveals Sexual Dimorphism in the Retina and RPE of C57BL6 mice.

Abstract

Background Sex as a biological variable is not a common consideration in molecular mechanistic or preclinical studies of retinal diseases. Understanding the sexual dimorphism of adult RPE and retina under physiological conditions is an important first step in improving our understanding of sex-based physio-pathological mechanisms. Methods Isobaric tags for relative and absolute quantitation (iTRAQ) were used for quantitative proteomics of male and female mouse retina and RPE (10 mice of each sex for each tissue type). Differentially expressed proteins were subjected to Gene Ontology (GO) analysis and Ingenuity Pathway Analysis (IPA). Results Differential expression analysis identified 38 differentially expressed proteins in the retina and 82 differentially expressed proteins in the RPE. Ingenuity pathway analysis identified the top canonical pathways differentially activated in the retina to be calcium transport I, nucleotide excision repair, fatty acid-b oxidation I and asparagine biosynthesis. In the RPE, the top canonical pathways were calcium signaling, dilated cardiomyopathy signaling, actin cytoskeletal signaling and RHOGDI signaling. Conclusions These results provide insights into sex differences in the retina and RPE proteome of mice and begin to shed clues into the sexual dimorphism seen in retinal diseases.