Comparative analysis of secretory factors from permanent- and deciduous-teeth periodontal ligament cells

Objective Studies of regenerative therapies have focused on the paracrine effects of mesenchymal stem cells, but little has been revealed about the humoral factors of periodontal ligament (PDL) stem cells. The aim of this study was to identify and compare the secretory factors of human permanent- and deciduous-teeth PDL cells (P-PDL and D-PDL cells, respectively) in order to understand the characteristics of these cells and their potential applications in regenerative therapies. Design Conditioned media were collected from P-PDL and D-PDL cells (P-PDL-CM and D-PDL-CM, respectively). These media were analyzed with high-performance liquid-chromatography-coupled electrospray ionization tandem mass spectrometry and a cytokine membrane assay. In addition, Western blot analysis was performed to verify the differences between the two media. Results Cytokines related to neurogenesis (NT-3 and NT-4) and angiogenesis-related cytokines (EGF and IGF-1) were identified in P-PDL-CM. The expression levels of immune-response-related cytokines (interleukins I, II, and IV) and secreted proteins related to tissue degradation and catalytic activities (matrix metallopeptidase 1 (MMP1), Proteasome subunit, alpha type, 1 (PSMA1), and cullin 7 (CUL7)) were higher in D-PDL-CM. Vasorin (VASN) was expressed more strongly in P-PDL-CM, but tudor domain containing 7 (TDRD7) was expressed more strongly in D-PDL-CM in Western blot analysis. Conclusion The cytokine expressions of the two cell types showed different patterns, especially in neurogenesis and immune responses. P-PDL cells are more suitable candidates for applications in regenerative therapies.