BACKGROUND AND OBJECTIVE: Although substance P (SP) stimulates bone resorption activity and this is reported to be correlated with the degree of periodontal inflammation, it is unclear how human periodontal ligament cells regulate neuropeptide-induced osteoclastogenesis or the possible involvement of heme oxygenase-1 (HO-1) might be. This study examines how SP affects osteoprotegerin (OPG) and RANKL expression via HO-1. MATERIAL AND METHODS: Using immortalized human periodontal ligament cells, the effects of SP on the expression of HO-1, RANKL and OPG mRNA and proteins were determined by RT-PCR and western blotting, respectively. Various concentrations of SP (10(-7), 10(-8), 10(-9) and 10(-10) m) were added to the medium, and the cells were treated for 0, 0.25, 0.5, 1, 2 and 3 d. RESULTS: Substance P upregulated RANKL and HO-1 and downregulated OPG mRNA and protein expression in periodontal ligament cells, in a concentration- and time-dependent manner. A HO-1 inducer inhibited both the upregulation of RANKL expression and downregulation of OPG expression by SP in periodontal ligament cells. By contrast, treatment with a HO-1 inhibitor or HO-1 small interferring RNA (siRNA) enhanced SP-stimulated RANKL expression. Inhibitors of ERK and p38 MAP kinases, phosphoinositide 3-kinase and nuclear factor-kappaB blocked the effects of SP on RANKL expression in periodontal ligament cells. CONCLUSION: These results suggest that SP stimulates osteoclastic differentiation by increasing the expression of RANKL vs. OPG via the HO-1 pathway in periodontal ligament cells. The HO-1 pathway may be an effective therapeutic target for inhibiting chronic periodontitis involving alveolar bone resorption.
BACKGROUND AND OBJECTIVE: Although substance P (SP) stimulates bone resorption activity and this is reported to be correlated with the degree of periodontal inflammation, it is unclear how human periodontal ligament cells regulate neuropeptide-induced osteoclastogenesis or the possible involvement of heme oxygenase-1 (HO-1) might be. This study examines how SP affects osteoprotegerin (OPG) and RANKL expression via HO-1. MATERIAL AND METHODS: Using immortalized human periodontal ligament cells, the effects of SP on the expression of HO-1, RANKL and OPG mRNA and proteins were determined by RT-PCR and western blotting, respectively. Various concentrations of SP (10(-7), 10(-8), 10(-9) and 10(-10) m) were added to the medium, and the cells were treated for 0, 0.25, 0.5, 1, 2 and 3 d. RESULTS:Substance P upregulated RANKL and HO-1 and downregulated OPG mRNA and protein expression in periodontal ligament cells, in a concentration- and time-dependent manner. A HO-1 inducer inhibited both the upregulation of RANKL expression and downregulation of OPG expression by SP in periodontal ligament cells. By contrast, treatment with a HO-1 inhibitor or HO-1 small interferring RNA (siRNA) enhanced SP-stimulated RANKL expression. Inhibitors of ERK and p38 MAP kinases, phosphoinositide 3-kinase and nuclear factor-kappaB blocked the effects of SP on RANKL expression in periodontal ligament cells. CONCLUSION: These results suggest that SP stimulates osteoclastic differentiation by increasing the expression of RANKL vs. OPG via the HO-1 pathway in periodontal ligament cells. The HO-1 pathway may be an effective therapeutic target for inhibiting chronic periodontitis involving alveolar bone resorption.
Authors: Magdalena Kozakowska; Maciej Ciesla; Anna Stefanska; Klaudia Skrzypek; Halina Was; Agnieszka Jazwa; Anna Grochot-Przeczek; Jerzy Kotlinowski; Agnieszka Szymula; Aleksandra Bartelik; Milena Mazan; Oleksandr Yagensky; Urszula Florczyk; Krzysztof Lemke; Anna Zebzda; Grzegorz Dyduch; Witold Nowak; Krzysztof Szade; Jacek Stepniewski; Marcin Majka; Rafal Derlacz; Agnieszka Loboda; Jozef Dulak; Alicja Jozkowicz Journal: Antioxid Redox Signal Date: 2011-10-19 Impact factor: 8.401