Cigarette Smoke-Regulated Genes of Filifactor alocis, An Emerging Periodontal Pathogen

Objectives: Cigarette consumption is an established risk factor for chronic periodontitis. Prior studies have shown that cigarette smoke extract (CSE) can induce profound phenotypic changes in Porphyromonas gingivalis and alter the virulence of this important periodontal pathogen. We hypothesized that CSE might also alter gene expression in Filifactor alocis, a Gram-positive, anaerobic, tobacco-associated emerging oral pathogen.
Methods: F. alocis was grown in CSE-conditioned (1000 ng/ml nicotine equivalents) or control medium. CSE-regulated genes were identified by RNA-Seq analysis. Validation of select, differentially expressed genes was performed by qPCR analysis.
Results: Approximately 5% of F. alocis genes were found to be differentially expressed when exposed to cigarette smoke. These included genes responsible for DNA replication, repair and transfer; protein translocation; fimbrial and pili assembly; and several metabolic processes.
Conclusions: Further interrogation of the tobacco-regulated transcriptome may provide some of the first information as to how smoking may influence the F. alocis phenotype in a manner likely to promote colonization and infection.