Proteomic shifts in multi-species oral biofilms caused by Anaeroglobus geminatus

Anaeroglobus geminatus is a relatively newly discovered putative pathogen, with a potential role in the microbial shift associated with periodontitis, a disease that causes inflammatory destruction of the periodontal tissues, and eventually tooth loss. This study aimed to introduce A. geminatus into a polymicrobial biofilm model of relevance to periodontitis, and monitor the proteomic responses exerted to the rest of the biofilm community. A. geminatus was grown together with another 10-species in a well-established “subgingival” in vitro biofilm model. Its effects on the other species were quantitatively evaluated by qPCR and label-free proteomics. A. geminatus caused a significant increase in P. intermedia numbers, but not the other species in the biofilm. Whole cell proteome profiling of the biofilms by LC-MS/MS identified a total of 3213 proteins. Label-free quantitative proteomics revealed that 187 proteins belonging to the other 10 species were differentially abundant when A. geminatus was present in the biofilm. The species with most up-regulated and down-regulated proteins were P. intermedia and S. oralis, respectively. Regulated proteins were of primarily of ribosomal origin, and other affected categories involved proteolysis, carbon metabolism and iron transport. In conclusion, A. geminatus can be successfully grown in a polymicrobial biofilm community, causing quantitative proteomic shifts commensurate with increased virulence properties.