TJP1 and periodontitis: For example, administration of P. gingivalis, a major causative agent in the development of chronic periodontitis, induces intestinal barrier dysfunction via the downregulation of tight junction proteins such as tight junction protein 1 (TJP1) and occludin, and causes intestinal inflammation via upregulation of pro-inflammatory cytokines such as IL-6 and IFN-γ [45,46,49,51].