Spry2 is a novel therapeutic target for periodontal tissue regeneration through fibroblast growth factor receptor signaling and epidermal growth factor signaling

Sprouty2 (Spry2) inhibits the activation of the extracellular signal-regulated kinase (ERK) pathway via receptor tyrosine kinase signaling. In a recent paper published in Journal of Cellular Biochemistry, we demonstrated that transfection of a dominant-negative mutant of Spry2 enhanced fibroblast growth factor (FGF)- and epidermal growth factor (EGF)-induced ERK activation in osteoblasts. In contrast, it decreased their activation in gingival epithelial cells. Consistent with these observations, the sequestration of Spry2 increased osteoblast proliferation by FGFR and EGFR stimulation, whereas it decreased gingival epithelial cell proliferation via the ubiquitination and degradation of EGF receptors (EGFR). In addition, reduction of Spry2 activity upregulated Runx2 expression and downregulated Twist, a negative regulator of Runx2 through FGFR and EGFR signaling, resulting in enhanced osteoblastogenesis in osteoblasts. Furthermore, we also found that suppression of Spry2 upregulated cell proliferation and migration in human periodontal ligament cell lines when they were stimulated by both FGF and EGF, and led to a shift in macrophage polarization, exerted immunosuppressive and tissue-repairing effects in macrophages. These results suggest that the application of a Spry2 inhibitor may effectively resolve inflammation by periodontitis and allow periodontal ligament and alveolar bone to grow and block the ingrowth of gingival epithelial cells in bony defects, biologically mimicking the barrier effect seen in conventional GTR. This approach has potential for developing a new regeneration strategy.