Gingivitis Pathogenesis Involves Upregulation of Glycolysis and Citric Acid Cycle Activity Mediated by Bacterial Virulence Factors

This research analyzed metabolomic and proteomic differences between participants with gingivitis (>20 bleeding sites) and generally healthy participants (≤3 bleeding sites) at baseline and 4 weeks post stannous fluoride (SnF2) dentifrice treatment. Sixty-two metabolites were different (p < 0.05) between groups at baseline. Forty cytokines were analyzed using immunoassays and a group of proinflammatory cytokines (IL-1α, IL-1β, TNF-α, SAA, ICAM-1, VCAM-1) was elevated in participants with gingivitis (p < 0.1) versus healthy gingiva at baseline, with C-reactive protein (p < 0.05) being significantly elevated. Proteomic analysis carried out in baseline oral lavage revealed four of the top hits (p < 0.0004) were central-metabolism-related: aldolase A, triosephosphate isomerase, lactate dehydrogenase, and malate dehydrogenase. Enzymatic assays confirmed the proteomic finding that malate dehydrogenase and triosephosphate isomerase activities were elevated in gingivitis samples; SnF2 dentifrice treatment reduced their activity. Collectively, 20 proteins with the lowest p-values in oral lavage appeared to be indicative of periodontal health, potentially forming the basis to cluster samples into healthy and unhealthy groups. A TLR-ATP biosensor model was established and demonstrated that microbial virulence factors induced the observed changes in oral lavage. Combined findings suggest gingivitis involves upregulation of host cell bioenergetic processes involving enzymatic activity in the glycolysis and citric acid cycle pathways.