Peptidomics Analysis Reveals Serum Biomarkers in Spinal Cord Injury Patients

Spinal cord injury (SCI) is a severe traumatic disease, always resulting in neuronal injury. In this study, we aimed to exhibit a peptidome profile of serum from patients with SCI. A label-free peptidomics strategy was used to analyze the differentially expressed peptides (DEPs). Then, gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses was used to evaluate the function of the peptides precursors proteins. Also, the protein-protein interaction networks were mapped using STRING database. Finally, parallel reaction monitoring assays were used to validate the expression of candidate peptides. We identified 217 DEPs including 29 upregulated peptides and 188 downregulated peptides in SCI group. Many pathways such as Platelet activation, Complement and coagulation cascades, Focal adhesion were enriched. Seven peptides including PSPRPSP, RPPGFSP, DKPDMAEIEKFDKSKLK, STTAVVTNPKE, GHAGAQGPPGPPG, SMPPAQQQITS and SKVLPIQDNVSK were significantly changed between SCI patients and healthy people. Peptidomics provide a powerful tool to find the variation of SCI. RPPGFSP, DKPDMAEIEKFDKSKLK and SMPPAQQQITS may play important roles in SCI. However, the specific function of these peptides and whether they can be used as therapeutic targets for SCI need to be further investigated.