IADR Abstract Archives
Lipopolysaccharide-Induced Adenosine Triphosphate Regulates Inflammatory Responses Of Periodontal Ligament Cells
Objectives: Many stimuli, i.e., mechanical stresses or inflammation, induce the release of adenosine triphosphate (ATP) by human periodontal ligament cells (HPDLCs). Extracellular ATP (eATP) affects HPDLCs’ functions like immunosuppressive action and inflammatory responses. Lipopolysaccharide (LPS) is the key factor involved in periodontal inflammation. However, the possible correlation and detailed mechanism of inflammatory mediated eATP by LPS and inflammatory cascade formation in HPDLCs is unclarified. The objective of this study was to examine the role of eATP on the responses of HPDLCs concerning inflammatory actions after LPS treatment.
Methods: HPDLCs were stimulated with P. gingivalis LPS prior to ATP release measurement using a bioluminescence assay. HPDLCs were treated with eATP. The expression of pro-inflammatory (COX2, IL1B, IL6, IL8, IL12, TNFA) and anti-inflammatory (IL4, IL10) was determined. Specific P2X7 receptor inhibitors (BBG and KN62), specific P2Y1 receptor inhibitors (MRS2179), calcium chelator (EGTA), PKC inhibitors, NF-κB activation inhibitors, cAMP-dependent PKA inhibitors (H89 dihydrochloride) and activator (forskolin) were used to dissect the mechanism of eATP-induced inflammatory responses by HPDLCs.
Results: LPS induced ATP release by HPDLCs. 50 μM eATP increased pro-inflammatory genes expression (COX2, IL1B, IL6, IL8, IL12, TNFA). 500 μM eATP enhanced anti-inflammatory gene expression (IL4, IL10). BBG, KN62, and NF-κB activation inhibitors impeded eATP-induced pro-inflammatory gene expression. MRS2179 and H89 markedly suppressed eATP-induced anti-inflammatory (IL4 and IL10) gene expression, while forskolin further enhanced the expression of those genes.
Conclusions: HPDLCs respond to LPS by releasing ATP. eATP has dose-dependent dual functions on inflammatory responses of HPDLCs via different pathways. As regulation of inflammation is important in regeneration, eATP may help to limit inflammation and trigger the regeneration of periodontium.
Methods: HPDLCs were stimulated with P. gingivalis LPS prior to ATP release measurement using a bioluminescence assay. HPDLCs were treated with eATP. The expression of pro-inflammatory (COX2, IL1B, IL6, IL8, IL12, TNFA) and anti-inflammatory (IL4, IL10) was determined. Specific P2X7 receptor inhibitors (BBG and KN62), specific P2Y1 receptor inhibitors (MRS2179), calcium chelator (EGTA), PKC inhibitors, NF-κB activation inhibitors, cAMP-dependent PKA inhibitors (H89 dihydrochloride) and activator (forskolin) were used to dissect the mechanism of eATP-induced inflammatory responses by HPDLCs.
Results: LPS induced ATP release by HPDLCs. 50 μM eATP increased pro-inflammatory genes expression (COX2, IL1B, IL6, IL8, IL12, TNFA). 500 μM eATP enhanced anti-inflammatory gene expression (IL4, IL10). BBG, KN62, and NF-κB activation inhibitors impeded eATP-induced pro-inflammatory gene expression. MRS2179 and H89 markedly suppressed eATP-induced anti-inflammatory (IL4 and IL10) gene expression, while forskolin further enhanced the expression of those genes.
Conclusions: HPDLCs respond to LPS by releasing ATP. eATP has dose-dependent dual functions on inflammatory responses of HPDLCs via different pathways. As regulation of inflammation is important in regeneration, eATP may help to limit inflammation and trigger the regeneration of periodontium.