[The application of iTRAQ quantitative proteomics in familial keloid].

Objective: To identify the special biomarkers and the differentially expressed proteins in keloid tissue and to explore the pathogenesis characteristics of familial keloid by comparing the protein expression differences among familial keloid(FK),sporadic keloid (SK),hypertrophy scar (HS),normal scar (NS).

Methods: The tissue specimens of FK,SK,HS and NS(6 specimens in each group),were digested, taged and analysed using quantitative proteomic isobaric tags for relative and absolute quantitation (iTRAQ) labeling technology. A difference greater than 1.2 folds and P ＜ 0.05 were selection criteria for differencial expression proteins. Then bioinformatics analysis was applied. The expressions of 2 differential proteins were validated using Western Blot analysis.

Results: A total of 2 450 differentially expressed proteins were identified. Compared with NS,250 up-regulated and 281 down-regulated proteins were identified in FK;281 up-regulated and 232 down-regulated proteins were identified in SK;199 up-regulated and 233 down-regulated proteins were identified in HS. Compared with SK,64 up-regulated and 164 down regulated proteins were identified in FK;79 up-regulated and 169 down-regulated proteins were identified in HS. Compared with HS,124 up-regulated and 115 down-regulated proteins were identified in FK. These different proteins were concentrated in several vital signal pathways such as the extracellular matrix protein, cell adhesion and biological metabolism pathways. The variation trend of 2 differentially expressed proteins (P3H1 and RCN-3) were validated by Western Blot.

Conclusions: Proteomic analysis can identify the proteins with variance of keloid, hypertrophy scar and normal skin. Further investigations of these differential proteins may reveal the pathogenesis of keloid and provide new treatments for it.