ITRAQ-Based Quantitative Proteomic Analysis of Tear Fluid in a Rat Penetrating Keratoplasty Model With Acute Corneal Allograft Rejection.

Abstract

This study aimed to develop a greater understanding of the mechanisms underlying acute corneal allograft rejection by identifying differentially expressed tear proteins at defined stages and discovering potentially important proteins involved in the process. The isobaric tags for relative and absolute quantitation (iTRAQ)-two-dimensional liquid chromatography-tandem mass spectrometry (2DLC-MS/MS) technique was used to identify tear proteins showing significant alterations in a rat penetrating keratoplasty model at different time points. Bioinformatics technology was applied to analyze the significant proteins, and a potential protein was verified by Western blotting. A total of 269 proteins were quantified, and 118 proteins were considered to be significantly altered by at least 2.0- or 0.5-fold. For gene ontology annotations, the top enrichments were neurological disease, free radical scavenging, cell death and survival, and cell movement. For pathway analyses, the top enrichments were LXR/RXR activation, acute phase response signaling, clathrin-mediated endocytosis signaling, and coagulation system. Coronin-1A was verified as a potential protein involved in the early stage of acute corneal allograft rejection. This study first demonstrates that tear proteomics is a powerful tool for better understanding of the mechanisms underlying acute corneal rejection, and that coronin-1A in tears might be closely related to allograft rejection.