Porphyromonas gingivalis initiates a mesenchymal-like transition through ZEB1 in gingival epithelial cells

The oral anaerobe Porphyromonas gingivalis is associated with the development of cancers including oral squamous cell carcinoma (OSCC). Here we show that infection of gingival epithelial cells with P. gingivalis induces expression and nuclear localization of the ZEB1 transcription factor which controls epithelial-mesenchymal transition (EMT). P. gingivalis also caused an increase in ZEB1 expression as a dual species community with Fusobacterium nucleatum or Streptococcus gordonii. Increased ZEB1 expression was associated with elevated ZEB1 promoter activity and did not require suppression of the miR-200 family of micro RNAs. P. gingivalis strains lacking the FimA fimbrial protein were attenuated in their ability to induce ZEB1 expression. ZEB1 levels correlated with an increase in expression of mesenchymal markers, including vimentin and MMP-9, and with enhanced migration of epithelial cells into matrigel. Knockdown of ZEB1 with siRNA prevented the P. gingivalis-induced increase in mesenchymal markers and epithelial cell migration. Oral infection of mice by P. gingivalis increased ZEB1 levels in gingival tissues, and intracellular P. gingivalis were detected by antibody staining in biopsy samples from OSCC. These findings indicate that FimA-driven ZEB1 expression could provide a mechanistic basis for a P. gingivalis contribution to OSCC

Functional dissection of polymicrobial synergy between Porphyromonas gingivalis and Streptococcus gordonii

Whole proteome proteomics data for P. gingivalis in the presence or absence of 4 aminobenzoate/para-amino benzoic acid (pABA)Many human infections are polymicrobial in origin, and synergistic interactions among community inhabitants control colonization and pathogenic potential (Murray et al., 2014). However, few interspecies interactions have been functionally dissected at the molecular level or characterized on a systems level. Periodontitis, which is the sixth most prevalent infectious disease worldwide (Kassebaum et al., 2014), is associated with a dysbiotic microbial community, and the keystone pathogen Porphyromonas gingivalis forms synergistic communities with the accessory pathogen Streptococcus gordonii (Lamont and Hajishengallis, 2015). P. gingivalis and S. gordonii communicate through co-adhesion and metabolite perception, and close association between P. gingivalis and S. gordonii results in significant changes in the expressed proteomes of both organisms (Kuboniwa et al., 2012, Hendrickson et al., 2012). Here we show that streptococcal 4 aminobenzoate/para-amino benzoic acid (pABA) is required for maximal accumulation of P. gingivalis in communities with S. gordonii. Exogenous pABA upregulates production of fimbrial interspecies adhesins and of a tyrosine phosphorylation-dependent signaling system in P. gingivalis. Consequently, fimbrial-dependent attachment and invasion of epithelial cells by P. gingivalis is also increased by pABA. Moreover, trans-omics studies performed by proteomics and metabolomics showed that pABA induces metabolic shifts within P. gingivalis, predominantly folate derivative biosynthesis. In a murine oral infection model, pABA increased colonization and survival of P. gingivalis, but did not increase virulence. The results establish streptococcal pABA as a major component of the interspecies S. gordonii-P. gingivalis interaction which regulates distinct aspects of polymicrobial synergy