Induction of MCP-1 by Porphyromonas gingivalis in human gingival fibroblasts

Objectives: Porphyromonas gingivalis, based on the diversity of fimA genes encoding each fimbirae subunit, can be classified into six genotypes (type I - V and I b), and type II fimA genotypes of P.gingivalis is strongly associated with adult periodontitis. However, the importance of specific fimA types in the immune response is unknown. Monocyte Chemoattractant Protein-1, produced by gingival tissues, is involved in the mechanism of monocyte recruitment from the circulating pool into periodontal tissues . The aim of this study was to assess the degree of MCP-1 induction in human gingival fibroblasts by P. gingivalis with different fimA genotypes.

Methods: HGFs , cultured at four to five passages, were stimulated with live P. gingivalis ATCC 33277 (type I), WCSP115 (type II), WCSP1.5 (type III) or W83 (type IV). Culture supernatant was collected at different time intervals (1h, 3h, 6h and 12h) , MCP-1 protein levels in the culture supernatants were assessed by ELISA, Real-time RT-PCR was used to determine the expression of MCP-1 mRNA.

Results: Significant levels of MCP-1 induction were observed from 1h post-infection for all bacterial strains. However, type II P.gingivalis infection showed more statistical MCP-1 mRNA and protein induction than other fimA genotypes at all time points, while Type III was weaker than other fimA genotypes during the experiment.

Conclusions: This study demonstrated that HGFs could produce MCP-1 as a result of stimulation by P. gingivalis, and P. gingivalis fimA genotypes may be related with the effect of MCP-1 inductions in HGFs. type II fimA was more effective than other fimA types for the induction of MCP-1 production in both protein and mRNA levels. The secretion of high levels of MCP-1 resulting from interaction of type II P.gingivalis with HGFs could enhance the accumulation and activation of monocytes, and aggregate the inflammation and destruction of periodontal tissue.