Abstract 3713: Receptor for Advanced Glycation Endproducts Amplifies Vascular Inflammation Elicited by a Periodontal Pathogen
Receptor for advanced glycation endproducts (RAGE) regulates vascular inflammation and its antagonism or deletion in ApoE−/− mice reduces atherosclerosis. A link between periodontal infections and an increased risk for vascular disease has been demonstrated. Porphyromonas gingivalis (Pg), a major periodontal pathogen, localizes in human atherosclerotic plaques, accelerates atherosclerosis in ApoE−/− mice, and invades vascular cells. We hypothesized that RAGE is involved in this pathogen’s contribution to atherogenesis. Murine aortic endothelial cells (MAEC) from C57BL/6 (WT) mice were infected, or not, with Pg strain 381. Generation of RAGE ligands, AGEs and high mobility group box 1 (HMGB1), was assessed by ELISA and immunoblotting, respectively. Infection with Pg 381 significantly increased AGE production by 2.4- and 3.3-fold compared to non-infected control (NI) at 6h (p=0.01) and 24h (p=0.03) post-infection, respectively (n=3). Enhanced HMGB1 cellular release was evident in Pg 381-infected cell lysates 6h post-infection (5.8-fold vs. NI, p=0.03; n=3). Similar findings were observed in primary human aortic endothelial cells. Pg 381 infection significantly increased monocyte chemoattractant protein 1 (MCP1) in WT MAEC supernatants (110 ± 3 pg/ml) vs. NI (57 ± 3 pg/ml) 6h post-infection (p<0.001, n=3), but had a minimal effect in MAEC from RAGE−/− mice (75 ± 7 pg/ml) vs. NI (63 ± 2 pg/ml; p=0.08, n=3). Infection with DPG3, a non-invasive mutant of Pg 381, failed to induce any of the above effects. In other experiments, WT, RAGE−/−, ApoE−/− and ApoE−/−RAGE−/− mice were orally infected, or not, with Pg 381. Mice in all 8 groups were sacrificed at 10 weeks of age, 2 weeks post-infection. qPCR array profiling of atherosclerosis-related genes in thoracic aortas (2 arrays/group) revealed that Pg infection upregulated expression of several inflammatory, cell adhesion and coagulation genes by 2- to 4-fold compared to NI. A protective effect of RAGE deletion was apparent in infected ApoE−/−RAGE−/− aortas, as genes involved in inflammatory/stress response, lipid transport and cell adhesion were downregulated by 2- to 3-fold compared to infected ApoE−/− aortas. These findings implicate RAGE in the amplification of vascular inflammation triggered by Pg.