Plasminogen Activation in Oral Mucosal Immunopathology

The Plg (plasminogen)/Pln (plasmin) system plays a broad range of roles in maintaining homeostasis at the oral mucosa, including homeostatic inflammation, tissue remodeling, and wound healing. Deregulation of these processes can lead to either increased or decreased proteolytic activity of Pln and, thereby, oral mucosal immunopathology. Here, we present a basic overview of the PAS (Plg activation system) components in the oral cavity and discuss how these factors are involved in oral mucosal homeostasis and disease pathogenesis. We reason that the role of the Plg/Pln system becomes evident in individuals with the Mendelian genetic defect, congenital Plg deficiency, who are predisposed to severe periodontitis in childhood due to defective fibrinolysis. Consistent with Plg deficiency as a risk factor for periodontitis, recent discovery of significant association between genetic polymorphisms in PLG and periodontal disease suggests PLG variants as candidate risk indicators for common forms of periodontitis.