The effects of LPS on adhesion and migration of human dental pulp stem cells in vitro.

OBJECTIVES The aim of the present study was to investigate the effects of lipopolysaccharide (LPS) on the migration and adhesion of human dental pulp stem cells (hDPSCs) and the associated intracellular signalling pathways. METHODS hDPSCs obtained from impacted third molars were exposed to LPS and in vitro cell adhesion and migration were evaluated. The effects of LPS on gene expression of adhesion molecules and chemotactic factors were investigated using quantitative real-time reverse-transcriptase polymerase chain (qRT-PCR). The potential involvement of nuclear factor NF-kappa-B (NF-κB) or mitogen-activated protein kinase (MAPK) signalling pathways in the migration and adhesion of hDPSCs induced by LPS was assessed using a transwell cell migration assay and qRT-PCR. RESULTS LPS promoted the adhesion of hDPSCs at 1μg/mL and 10μg/mL concentrations, 1μg/mL LPS showing the greater effect. Transwell cell migration assay demonstrated that LPS increased migration of hDPSCs at 1μg/mL concentration while decreasing it significantly at 10μg/mL. The mRNA expressions of adhesion molecules and chemotactic factors were enhanced significantly after stimulation with 1μg/mL LPS. Specific inhibitors for NF-κB and extracellular signal regulated kinases (ERK), c-Jun N-terminal kinase (JNK), and P38, markedly antagonised LPS-induced adhesion and migration of hDPSCs and also significantly abrogated LPS-induced up-regulation of adhesion molecules and chemotactic factors. In addition, specific inhibitors of SDF-1/CXCR4, AMD3100 significantly diminished LPS-induced migration of hDPSCs. CONCLUSIONS LPS at specific concentrations can promote cell adhesion and migration in hDPSCs via the NF-κB and MAPK pathways by up-regulating the expression of adhesion molecules and chemotactic factors. CLINICAL SIGNIFICANCE LPS may influence pulp healing through enhancing the adhesion and migration of human dental pulp stem cells when it enters into pulp during pulp exposure or deep caries.