ABSTRACT: Investigation of transcripts differentially regulated in oral epithelial cells in response to P. gingivalis, but overridden or reversed by S. gordonii.
Project description:Periodontal diseases are one of the most common human maladies and appear to be caused by the interaction of proximal pathogens such as Porphyromonas gingivalis but only as part of the polymicrobial community known as dental plaque. Streptococcus gordonii is an early colonizing oral organism that binds to oral surfaces and provides adherence for organisms such as P. gingivalis. Together P. gingivalis and S. gordonii form one of the simplest models of potentially pathogenic dental plaque. We used RNA sequencing to monitor the transcriptome of P. gingivalis over time in a biofilm model both in the presence and absence of S. gordonii. Samples were taken at 5, 30, 120, 240, and 360 minutes after shifing from planktonic to sessile conditions and growth media to PBS. When compared to planktonic cells increased transcripts were found for stress, amino acid catabolism, and comeptence and decreased transcripts for DNA replication. The presence of S. gordonii resulted in fewer changes from planktonic cells implying physiological support to Pl gingivalis making the transition from planktonic to sessile easier.
Project description:Transcriptional profiling was utilized to define the biological pathways of gingival epithelial cells modulated by mono- and complex co-culture with oral commensal S. gordonii and pathogenic P. gingivalis. We used microarrays to detail the global programme of gene expression underlying infection and identified distinct classes of up- and down-regulated genes during this process. Experiment Overall Design: Gingival epithelial HIGK cells were sham infected (CTRL) and infected with either the oral commensal S. gordonii (Sg) or the pathogenic P. gingivalis (Pg) as well as co-cultured in mixed cultures of Sg and Pg (Sg+Pg). These samples were hybridized to Affymetrix microarrays. Understanding how host cells have adapted to commensals, and how barrier cells respond to limit their impact, provides a mechanistic biological basis of health in the mixed bacterial-human ecosystem of the oral cavity and provides insight on how the degree of complexity of a microbiome influences this balance.
Project description:Transcriptional profiling was utilized to define the biological pathways of gingival epithelial cells modulated by mono- and complex co-culture with oral commensal S. gordonii and pathogenic P. gingivalis. We used microarrays to detail the global programme of gene expression underlying infection and identified distinct classes of up- and down-regulated genes during this process. Keywords: infection state
Project description:Many human infections are polymicrobial in origin, and interactions among community inhabitants shape colonization patterns and pathogenic potential1. 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 worldwide2, ensues from the action of dysbiotic polymicrobial communities3. The keystone pathogen Porphyromonas gingivalis and the accessory pathogen Streptococcus gordonii interact to form communities in vitro and exhibit increased fitness in vivo3, 4. The mechanistic basis of this polymicrobial synergy, however, has not been fully elucidated. Here we show that streptococcal 4 aminobenzoate/para-amino benzoic acid (pABA) is required for maximal accumulation of P. gingivalis in dual species communities. Metabolomic and proteomic data showed that exogenous pABA is utilized for folate biosynthesis, and leads to decreased stress and elevated expression of fimbrial interspecies adhesins. Moreover, pABA increased the colonization and survival of P. gingivalis in a murine oral infection model. However, pABA also caused a reduction in virulence in vivo and suppressed extracellular polysaccharide production by P. gingivalis. Collectively, these data reveal a multidimensional aspect to P. gingivalis-S. gordonii interactions and establish pABA as a critical cue produced by a partner species that enhances fitness of P. gingivalis while diminishing virulence.
Project description: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.
Project description:The mechanisms through which oral commensal bacteria mitigates uncontrolled inflammatory responses in the oral mucosa remain unknown. Here we evaluated the ability of S. gordonii to stimulate the expression of miRNAs in oral epithelial cells with potential to target chemokine expression. The human oral epithelial cell line (OKF6) was exposed to different MOIs of S. gordonii for 24h and expression analysis of miRNAs performed using the Affymetrix platform.
Project description:We report the study of the mechanism of action of Porphyromonas gingivalis on human oral epithelial cells based on high-throughput sequencing technology. By acting Porphyromonas gingivalis and its metabolites on human oral epithelial cells separately, the mechanism of Porphyromonas gingivalis evading immune surveillance and causing local and deep tissue diffusion to induce systemic diseases was studied. This study provides a framework for studying the pathogenic mechanism of Porphyromonas gingivalis.
Project description:Transcriptional profiling was utilized to define the biological pathways of gingival epithelial cells modulated by co-culture with the oral commensal S. gordonii and the opportunistic commensal F. nucleatum. We used microarrays to detail the global programme of gene expression underlying infection and identified distinct classes of up- and down-regulated genes during this process. Experiment Overall Design: Gingival epithelial HIGK cells were sham infected (CTRL) and infected with either the oral commensal S. gordonii (Sg) or the opportunistic commensal F. nucleatum (Fn). These samples were hybridized to Affymetrix microarrays. Understanding how host cells have adapted to commensals, and how barrier cells respond to limit their impact, provides a mechanistic biological basis of health in the mixed bacterial-human ecosystem of the oral cavity.
Project description:Tn-Seq was used to identify S. gordonii genes that confer fitness during cooperative growth with P. gingivalis in a murine abscess model.