Proteomic profiling of posterior longitudinal ligament of cervical spine

Objective: To identify putative biomarkers for ossification of posterior longitudinal ligament (OPLL). Material and methods: Proteomic analysis was performed in 4 ligament samples from OPLL patients and healthy controls. RT-PCR was used to further verify the proteomic analysis results. Results: A total of 50 differentially expressed spots were detected in 2-D electrophoresis between the two groups. In protein/peptide analysis, 21 proteins or peptides were finally identified. Besides 13 hematic proteins and 2 unknown proteins, 6 other proteins were differentially expressed. Among them, carbonic anhydrase I, NAD(P) dependent steroid dehydrogenase-like, billiverdin reductase B and alpha-1 collagen VI were down-regulated, while osteoglycin and nebulin-related anchoring protein were upregulated. The results of NAD(P) dependent steroid dehydrogenase-like, alpha-1 collagen VI and nebulin-related anchoring protein were validated by RT-PCR. Conclusion: These differentially expressed proteins could play a role in the onset and progression of OPLL.