The Effect of Porphyromonas gingivalis Augmented Invasion by TNF-α on Gingival Fibroblasts Derived from Down Syndrome

It is well known the high prevalence periodontal disease in Down syndrome（DS）. Tumor necrosis factor alpha（TNF-α）augments invasion of Porphyromonas gingivalis（P. gingivalis）in human gingival epithelial cells. We examined the effect of TNF-α on invasion of P. gingivalis to gingival fibroblasts derived from individuals with DS（DGF）and the influence of the cellular response in DGF pretreated with TNF-α prior to inoculation of P. gingivalis. The invasion assay was performed using gingival fibroblasts derived from individuals with non-DS（NGF）and DGF treated with TNF-α prior to inoculation of P. gingivalis. The mRNA expression of interleukin 6（IL-6）and intercellular adhesion molecule 1（ICAM-1）were quantified using real time PCR. Furthermore, the protein expressions of TNF-α receptor（TNFR）I and II, and phosphorylation of p65 nu-clear factor-κB（NF-κB）and phosphorylation of extracellular signal-regulated kinase （ERK）1/2 were also performed in NGF and DGF pretreated with TNF-α prior to inoculation of P. gingivalis by Western blotting. The number of invasive P. gingivalis in TNF-α pretreated DGF was more than that in NGF. IL-6 and ICAM-1 mRNA expressions in DGF pretreated with TNF-α prior to inoculation of P. gingivalis were significantly higher than those in NGF. The relative signal intensity of TNFR I, phospho p-65 NF-κB, and phospho ERK1/2 were significantly higher than those in NGF. It was considered that TNFR I, phospho p65 NF-κB, and phospho ERK1/2 in DGF pretreated with TNF-α may contribute to enhancement of ICMA-1 mRNA expression and the infection of P. gingivalis. The collaboration of these protein and P. gingivalis may be a key factor for development of severe periodontal disease in DS. anaerobic conditions for 7 days. The colonies were count-ed to determine the number of colony - forming units （CFUs）of invasive P. gingivalis in fibroblast cells. Inva sion assays were performed 3 times for each sample.