Salivary proteomic profiling of hookah and conventional cigarette users without clinical oral disease: preliminary findings

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Introduction This study aimed to evaluate the profile of salivary proteins in young hookah and conventional cigarette users without apparent oral mucosal lesions, and to correlate the findings with clinical variables related to tobacco use. Methods Whole saliva samples were collected from three groups: exclusive frequent hookah smokers, exclusive frequent cigarette smokers, and non-smokers. Participants were healthy young adults (18–40 years) of both sexes with good general and oral health. LC-MS/MS analyses were performed using Synapt G2 HDMS (Waters) coupled to the nano Acquity Ultra Performance Liquid Chromatography (UPLC) chromatography system (Waters). Database searches were performed using PEAKS Studio X+. The groups were compared, and correlations between protein abundance and clinical variable, alcohol consumption, and duration of tobacco use were evaluated. Results and Conclusions The results revealed quantitative and functional changes in the salivary proteome of cigarette and hookah smokers, with enrichment of processes related to epigenetic regulation (chromatin/nucleosomes) and cell differentiation. However, cigarette exposure was associated with a more pronounced functional pattern. Direct comparison of hookah and cigarette smokers identified three differentially abundant proteins (DAPs) in the cigarette group (ALDH3A1, CSTA, and PGM2) and seven in the hookah group (LYPLAL1, IGLL5, PIP, PRSS8, UBA1, IGHV5-10-1, and SERPINB9). Finally, in silico validation using transcriptomic data from The Cancer Genome Atlas (TCGA) PanCancer Atlas database for head and neck squamous cell carcinoma demonstrated that several genes corresponding to salivary DAPs identified in smokers exhibit altered expression patterns in head and neck tumors, including Glucose-6-phosphate dehydrogenase, Scavenger receptor cysteine-rich protein DMBT1, Beta-2-glycoprotein 1, and Inter-alpha-trypsin inhibitor heavy chain H4. Implications This study demonstrates that salivary proteomics can reveal early molecular alterations associated with tobacco exposure. Cigarette and hookah smoking are associated with quantitative and functional changes in the salivary proteomic profile, with changes mainly occurring in epigenetic processes (chromatin/nucleosomes) and regulation of cell differentiation (megakaryocytes and myeloid cells). Exposure to cigarettes is associated with an apparently more pronounced functional pattern, and specific differences in protein abundance profiles exist between hookah and cigarette smokers. These findings support the potential use of saliva as a non-invasive diagnostic tool for monitoring the early biological effects of tobacco and for assessing oral cancer risk.