iTRAQ-based quantitative proteomic analysis and bioinformatics study of proteins in pterygia

Purpose: To analyze proteins in the tissue of pterygia, and to investigate their potential roles in pterygia, using the comparative proteomic technique of Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) coupled with offline 2DLC-MS/MS, Western-bolt. Method: The tissue of pterygia and healthy conjunctiva was collected from 10 pterygia patients (6 females, 4 males; average age was 52 years old; average course of disease was 6 years) in our hospital from September, 2015 to March, 2016. iTRAQ was used to analyze proteins in the patients' pterygia and healthy conjunctiva. Proteins with a fold change of >2. 0 or <0. 5 were considered to be significantly differentially expressed (with corrected p-values of <0. 1). The identified proteins were subjected to subsequent gene ontology analysis using the DAVID database. Then we confirmed the targeted proteins with western-blot. Results: 156 proteins that expressed differently between the pterygia and healthy conjunctiva were identified using iTRAQ analysis. Of these proteins, 18 were down-regulated, and 138 were up-regulated. On the basis of biological processes in gene ontology, the identified proteins were mainly involved in cellular process, metabolic process, developmental process, location, cellular component organization, Among these proteins, matrix Metalloproteinase 10 (MMP-10) and CD34 may have potential roles in the pathogenesis of pterygia. Then we confirmed with Western-bolt that MMP-10 and CD34 were up-regulated in pterygia. Conclusion: This study is the first to identify 156 proteins associated with pterygia with iTRAQ technology. Data in our study will aid in providing a better understanding of pterygia.