Proteome Analysis of Coinfection of Epithelial Cells with Filifactor alocis and Porphyromonas gingivalis Shows Modulation of Pathogen and Host Regulatory Pathways

Abstract

ABSTRACTChanges in periodontal status are associated with shifts in the composition of the bacterial community in the periodontal pocket. The relative abundances of several newly recognized microbial species, includingFilifactor alocis, as-yet-unculturable organisms, and other fastidious organisms have raised questions on their impact on disease development. We have previously reported that the virulence attributes ofF. alocisare enhanced in coculture withPorphyromonas gingivalis. We have evaluated the proteome of host cells andF. alocisduring a polymicrobial infection. Coinfection of epithelial cells withF. alocisandP. gingivalisstrains showed approximately 20% to 30% more proteins than a monoinfection. UnlikeF. alocisATCC 35896, the D-62D strain expressed more proteins during coculture withP. gingivalisW83 than withP. gingivalis33277. Proteins designated microbial surface component-recognizing adhesion matrix molecules (MSCRAMMs) and cell wall anchor proteins were highly upregulated during the polymicrobial infection. Ultrastructural analysis of the epithelial cells showed formation of membrane microdomains only during coinfection. The proteome profile of epithelial cells showed proteins related to cytoskeletal organization and gene expression and epigenetic modification to be in high abundance. Modulation of proteins involved in apoptotic and cell signaling pathways was noted during coinfection. The enhanced virulence potential ofF. alocismay be related to the differential expression levels of several putative virulence factors and their effects on specific host cell pathways.