Soft‐shelled turtles (Pelodiscus sinensis) are widely distributed in some Asian countries, and we previously reported that soft‐shelled turtle tissue could be a useful material for collagen. In the present study, we performed shotgun liquid chromatography (LC)/mass spectrometry (MS)‐based global proteomic analysis of collagen‐administered human keratinocytes to examine the functional effects of collagen from soft‐shelled turtle on human skin. Using a semiquantitative method based on spectral counting, we were able to successfully identify 187 proteins with expression levels that were changed more than twofold by the administration of collagen from soft‐shelled turtle. Based on Gene Ontology analysis, the functions of these proteins closely correlated with cell–cell adhesion. In addition, epithelial–mesenchymal transition was induced by the administration of collagen from soft‐shelled turtle through the down‐regulation of E‐cadherin expression. Moreover, collagen‐administered keratinocytes significantly facilitated wound healing compared with nontreated cells in an in vitro scratch wound healing assay. These findings suggest that collagen from soft‐shelled turtle provides significant benefits for skin wound healing and may be a useful material for pharmaceuticals and medical care products. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2403–2413, 2018.

Collagen peptides (CPs), derived by hydrolyzing collagen with chemicals or enzymes, are often used as functional materials, due to their various bioactivities and high bioavailability. A previous study by our group reported that collagen from soft‑shelled turtle, Pelodiscus sinensis, induces keratinocytes to undergo epithelial‑mesenchymal transition and facilitates wound healing. Therefore, CPs derived from soft‑shelled turtle collagen may have useful effects on the skin. In the present study, the functional effects of CPs on human skin were examined by analyzing CP‑treated human keratinocytes with a shotgun liquid chromatography/mass spectrometry‑based global proteomic approach. A semi‑quantitative method based on spectral counting was applied and 211 proteins that exhibited>2‑fold changes in expression after CP treatment were successfully identified. Based on a Gene Ontology analysis, the functions of these proteins were indicated to be closely linked with protein processing. In addition, CP treatment significantly increased the expression of calpain‑1, a calcium‑dependent intracellular cysteine protease. Furthermore, CP‑treated keratinocytes exhibited elevated interleukin (IL)‑1α and IL‑8 expression and reduced IL‑6 expression. CPs also induced the expression of proteins implicated in cell‑cell adhesion and the skin barrier. Therefore, CPs from soft‑shelled turtle may provide significant benefits for maintaining the biological environment of the skin, and may be useful as components of pharmaceuticals and medical products.