Metatranscriptomic analysis unveils functional alterations in subgingival biofilm of young smokers with periodontitis

The objective was to assess the influence of smoking on the subgingival metatranscriptomic profile in young patients affected by stage III/IV and generalized periodontal disease. Six young patients affected by periodontitis, including both smokers and non-smokers (n=3/group), were selected, following STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines for case-control reporting. Periodontal clinical measurements and subgingival biofilm samples were collected. RNA was extracted from biofilm and sequenced through Illumina HiSeq. Differential expression analysis utilized Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and differentially expressed genes were identified using the Sleuth package in R with a statistical cutoff of ≤0.05. A total of 3351 KEGGs were identified in the subgingival biofilm of both groups, and smoking habits altered the functional behavior of the subgingival biofilm, resulting in 304 differentially expressed KEGGs between groups. Moreover, seven pathways were modulated: glycan degradation, galactose metabolism, glycosaminoglycan degradation, oxidative phosphorylation, peptidoglycan biosynthesis, butanoate metabolism, and glycosphingolipid biosynthesis. Besides, smoking also altered the Antibiotic Resistance Genes (ARGs) levels in subgingival biofilm through the significant over-expression of genes related to beta-lactamase, permeability, antibiotic efflux pumps, and antibiotic-resistant synthetases. Given the limitations of a small sample size, our data suggests that smoking may influence the functional behavior of the subgingival biofilm, modifying pathways that negatively impact the behavior of the subgingival biofilm, potentially leading to a more virulent community. (2024-07-12)