Impact of smoking habit on the subgingival proteome in patients with periodontitis

Smoking is a critical risk factor for the development and progression of periodontitis. However, evidence of the effect of smoking on the subgingival proteome is scarce. Therefore, this study aimed to determine the impact of smoking on the overall proteome and differential expression of gingival crevicular fluid (GCF) proteins using the sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomic technique. For this purpose, GCF samples were collected from 40 subjects with periodontitis, of which 17 were smokers, 10 were ex-smokers, and 13 were non-smokers. These samples were analysed by SWATH-MS, and proteins were identified using the UniProt human-specific database. Analysis of the overall proteome showed that its distribution was not significantly different between smokers, ex-smokers, and non-smokers. However, several proteins were found to be differentially expressed according to the smoking status. Smoking can increase the expression of several keratins and proteins related to hyperkeratinization of the epithelium. However, in ex-smokers, these proteins return to similar levels to those of non-smokers. Moreover, smoking may induce a lower expression of proteins related to adaptive immunity, such as immunoglobulins. This immunosuppressive effect may persist in ex-smokers.