The Effect Of LPS On Adhesion，Migtation And Adipogenic Differentiation Of Human Dental Pulp Stem Cells And Involving Signaling Pathway

When dentin was destroyed by caries, the bacteria and its toxic products could enterinto the pulp tissue and killed the odontoblasts, which would then result in dental pulpinflammation and reparative dentinogenesis. Recent studies have showed that hDPSCscould migrate into the lesions and then differentiate into odontoblast-like cells to formreparative dentin. However, it remain unclear about how baterial products, such as LPS,play in the process.Bacterial endotoxin LPS is the major pathogenic factor of G-bacteria which have beendemonstrated to be very important for development of inflammatory diseases. With thedevelopment of experimental technology and better understanding on inflammation, it wasrealized that LPS not only had the negative impacts through inducing the release of various cytokines and proteins in the immune system, but also had a favorable role inwound repairing and innate immunity. However, it remains unclear whether LPSinfluences the migration and adhesion and adipogenic differentiation of hDPSCs or not inan inflammatory state. Thus, this project aimed to investigate the role of LPS on themigration and adhesion and adipogenic differentiation of hDPSCs and involvingintracellular signal pathway. We have got the results as follows:1、The role of LPS in migration of hDPSCs.We fistly observe the effect of LPS on the migration of DPSCs by cell migration assay.It showed that0.1μg/ml LPS group have no effect on the migrationof DPSCs, while the1μg/ml and10μg/ml LPS groups markedly increased the migration of DPSCs comparedwith the control group. Then, the migration of DPSCs regulated by1μg/ml LPS wassignificantly reversed by pretreatment with specific inhibitor of NF-κB and P38, JNK andERK signaling pathways. In addition, some chemokines such as SDF-1、CXCR4、MCP-1、FGF2、MIP-1、TGF-β1and IL-8could be significantly increased by1μg/ml LPS, whichwas antangonized by pretreatment of specific inhibitors o f NF-κB and P38, JNK and ERKsignaling pathways, It suggested that LPS maybe promoted the migration of DPSCsthrough the NF-κB, P38, JNK and ERK signaling pathways.2、The role of LPS in adhesion of hDPSCs.In first, we checked the effect of LPS on the adhesion of DPSCs by cell adhesion assay.It showed that0.1μg/ml LPS group have no effect on the adhesion of DPSCs. while1μg/ml and10μg/ml LPS groups significantly enhanced the adhesion of DPSCs comparedwith the control group. Then, the adhesion of DPSCs regulated by1μg/ml LPS wassignificantly antagonized by pretreatment with specific inhibitor of NF-κB and P38, JNKand ERK signaling pathways. Moreover, some adhesion molecules such as VEGF, FN,ICAM-1and Integrin β1could be significantly upregulated by1μg/ml LPS, which wassuppressed by pretreatment of specific inhibitors of NF-κB and P38, JNK and ERKsignaling pathways,. It suggested that LPS maybe enhanced the adhesion of DPSCsthrough the NF-κB, P38, JNK and ERK signaling pathways.3、The role of LPS in adipogenic diffe rentiation of hDPSCs. To explore the effect of LPS on the adipogenic differentiation of DPSCs, we culturedhDPSCs with adipogenic induction medium and detected the the formation of lipiddroplets by oil red O staining after21d. It showed that1μg/ml and5μg/ml LPS group,not0.1μg/ml LPS group, significantly inhibited the formation of lipid droplets. Then,pretreatment of specific inhibitor of NF-κB, JNK and ERK signaling pathwayssignificantly reversed the effect of LPS. However, specific inhibitor of p38MAPK couldnot antagonized the effect of LPS. In addition, our results show that1μg/ml LPS couldsuppress the expressionofPPARγ、C/EBP-、C/EBP-β、C/EBP-by real-time PCR, whichwas antangonized by pretreatment of specific inhibitors of NF-κB and P38, JNK and ERKsignaling pathways, but not by specific inhibitors of p38MAPK. This indicated that LPScould suppress DPSCs adipogenic differentiation through the NF-κB, JNK and ERKsignaling pathways.In conclusion, Our results showed that LPS could enhance the adhesion and migrationof DPSCs migration,inhibit adipogenic differentiation of DPSCs, through NF-κB andMAPK signal pathway.