Effects of bacterial lipopolysaccharide on the mineralization and differentiation of periodontal ligament stem cells / 医学研究生学报

Objective Periodontal tissue engineering has shown a highlight prospect in the treatment of periodontitis,but the related clinical experiments have not achieved the predetermined goal. In this study,we analyzed the reasons for the limited clinical efficacy of periodontal tissue engineering. Methods We primarily cultured the periodontal tissue from the young permanent teeth extracted for or-thodontic treatment,isolated periodontal ligament stem cells (PDLSCs),and transplanted the well-grown third-generation PDLSCs onto the fluorapatite-polycaprolactone (FA-PCL) nanofiber scaffolds and PCL nanofiber scaffolds. We randomly divided the cells into groups A (cultured with 10 ng/mL porphyromonas gingivalis lipopo-lysaccharide (Pg-LPS)+FA-PCL),B (cultured with 10 ng/mL PG-LPS+PCL),C (cultured with 10 μg/mL PG-LPS+FA-PCL),D (cultured with 10 μg/mL PG-LPS+PCL),E (cultured with FA-PCL),and F (cultured with PCL),and observed their proliferation,differentiation and mineralization. Results The PDLSCs adhered and grew well after transplanted onto the nanofiber scaffolds and their proliferation significantly increased in groups A and B but decreased in C and D as compared with E and F. At 7 days,the expres-sions of ALP and mineralization-related genes runx2 and SPP1 in the PDLSCs were significantly higher in group E than in the other five groups (P<0.05),but higher groups A and C than in B and D as well as in A than in C. At 28 days,alizarin red and Von Kossa stai-ning showed a higher positivity in group E than in the other five groups,but higher groups A and C than in B and D as well as in A than in C. Conclusion The inflammatory environment not only affects the proliferation of PDLSCs,but also inhibits their differentiation and mineralization. The FA-PCL scaffold can reduce the cytotoxic effect of PG-LPS.

JAK/STAT Pathway Modulates on Porphyromonas gingivalis Lipopolysaccharide- and Nicotine-Induced Inflammation in Osteoblasts / 치위생과학회지

Bacterial infection and smoking are an important risk factors involved in the development and progression of periodontitis. However, the signaling mechanism underlying the host immune response is not fully understood in periodontal lesions. In this study, we determined the expression of janus kinase (JAK)/signal transducer and activator of transcription (STAT) on Porphyromonas gingivalis lipopolysaccharide (LPS)- and nicotine-induced cytotoxicity and the production of inflammatory mediators, using osteoblasts. The cells were cultured with 5 mM nicotine in the presence of 1 µg/ml LPS. Cell viability was determined using MTT assay. The role of JAK on inflammatory mediator expression and production, and the regulatory mechanisms involved were assessed via enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, and Western blot analysis. LPS- and nicotine synergistically induced the production of cyclooxgenase-2 (COX-2) and prostaglandin E₂ (PGE₂) and increased the protein expression of JAK/STAT. Treatment with an JAK inhibitor blocked the production of COX-2 and PGE₂ as well as the expression of pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin-1β (IL-1β), and IL-6 in LPS- and nicotine-stimulated osteoblasts. These results suggest that JAK/STAT is closely related to the LPS- and nicotine-induced inflammatory effects and is likely to regulate the immune response in periodontal disease associated with dental plaque and smoking.

The Lipopolysaccharide from Porphyromonas gingivalis Induces Vascular Permeability

Porphyromonas gingivalis, one of the major periodontal pathogens, is implicated in the initiation and progression of periodontal disease. The initial stages of periodontal inflammation are accompanied by vascular hyperpermeability. In our present study, we report that the P. gingivalis lipopolysaccharide (LPS) increases the mRNA expression of interleukin-8 (IL-8), a major inducer of vascular permeability, in vascular endothelial cells. P. gingivalis LPS also stimulated the induction of IL-8 secretion in endothelial cells. The P. gingivalis LPS-induced expression of IL-8 was primarily modulated by nuclear factor-kappaB (NF-kappaB). P. gingivalis LPS significantly enhanced the vascular permeability both in vitro and in vivo, and a blockade of the IL-8 receptor decreased the P. gingivalis LPS-induced vascular permeability. Taken together, these results suggest that P. gingivalis LPS increases vascular permeability through the NF-kappaB-dependent production of IL-8 in vascular endothelial cells.