Atherogenic Markers in P.gingivalis-Stimulated Dendritic Cells and Chronic Periodontitis in-situ

Objectives: Recent evidence has shown that dendritic cells infiltrate atherosclerotic plaques and express atherogenic markers of plaque instability including Hsp-70, C1Q, CCR2 and CXCL16.The sources of these dendritic cells in atherosclerotic plaques and the expression of these markers in chronic periodontitis (CP) is unclear. This is especially pertinent in view of histological evidence for activation and mobilization of dendritic cells in CP tissues and for epidemiological evidence linking CP to coronary artery disease. We propose here to analyze the expression of Hsp-70, C1Q, CCR2 and CXCL16 in human dendritic cells stimulated with the periodontal pathogen P.gingivalis (Pg) in vitro and in gingival tissues from patients with CP in situ.

Methods: Human monocyte-derived DCs were pulsed with wild-type fimbriated Pg381 for 3-18 hours and uptake of CFSE-labeled Pg monitored by FACS analysis. After isolation of total-RNA and synthesis of cDNA, quantitative real-time-PCR (qRT-PCR) was used to determine expression of atherogenic markers relative to untreated control DCs, normalized to b-actin and expressed as fold-changes in mRNA. Transcripts in healthy and inflamed gingival tissues were also analyzed by qRT-PCR.

Results: Pg associate with MDDCs rapidly and induce expression of mRNA for Hsp-70 (8.3-fold), C1Q (5.1-fold), CCR2 (2.5-fold) and CXCL16 (1.8-fold). In the diseased gingival tissues, we found increased, but variable, expression of mRNA for Hsp-70, C1Q, CCR2 and CXCL16.

Conclusion: Our results suggest that atherogenic markers involved in activation and mobilization of dendritic cells to atherosclerotic plaques are induced by P.gingivalis in vitro and in gingival tissues in situ. Atherosclerotic plaque instability can lead to plaque rupture, thrombosis and ultimately myocardial infarct or death.

1K23DE018187-01