Exclusive heat-not-burn cigarette smoking alters the profile of circulating microRNAs

BackgroundTraditional combustion cigarette (TCC) smoking is an established risk factor for several types of cancer and cardiovascular diseases. Circulating microRNAs (miRNAs) represent key molecules mediating pathogenetic mechanisms, and potential biomarkers for personalized risk assessment. TCC smoking globally changes the profile of circulating miRNAs. The use of heat-not-burn cigarettes (HNBCs) as alternative smoking devices is rising exponentially worldwide, and the circulating miRNA profiles in chronic HNBC smokers are unknown. We aimed at defining the circulating miRNA profile of chronic exclusive HNBC smokers, and identifying potentially pathogenetic signatures. MethodsSerum samples were obtained from 60 healthy young subjects, stratified in chronic HNBC smokers, TCC smokers, and Non Smokers (20 subjects each). Three pooled samples per group were used for small RNA sequencing, and the fourth sub-group constituted the validation set. FindingsDifferential expression analysis revealed 108 differentially expressed miRNAs; 72 exclusively in TCC, 10 exclusively in HNBC, and 26 in both smoker groups. KEGG pathway analysis on target genes of the commonly modulated miRNAs returned cancer and cardiovascular disease associated pathways. Stringent abundance and fold-change criteria nailed down our functional bioinformatic analyses to a network where miR-25-3p and miR-221-3p are main hubs. InterpretationOur results define for the first time the miRNA profile in the serum of exclusive chronic HNBC smokers and suggest a significant impact of HNBCs on circulating miRNAs. FundingSapienza University of Rome grant 2019, # RG11916B8621D7FF to GBZ and grant 2021 # RM12117A5D7688BC to RC. IC is supported by grants # RM12117A805ED2FD and # RG11916B85CDBF76 from Sapienza University of Rome, and by grant # RG1221816BC8E766 from the Italian Health Ministry. FP is supported by Grant # A0375-2020-36621 from Regione Lazio (POR-FESR 2014-2021).