Extracellular microRNAs in saliva

BackgroundMicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate messenger RNAs. Recent studies have demonstrated the presence of stable extracellular miRNAs that circulate in various body fluids, including saliva. The extracellular miRNAs are known to be secreted into the surrounding environment freely or within small vesicles called exosomes. Since saliva can be easily obtained in a non-invasive manner, salivary miRNAs are promising novel biomarkers for clinical applications.HighlightSeveral attempts using microarrays, quantitative real-time PCR, and high-throughput sequencing have been made to characterize salivary miRNAs. Differences in methodology, including saliva collection and exosome purification, can affect miRNA profiles.ConclusionThis review summarizes the findings of recent reports that have investigated salivary miRNAs with the aim of establishing novel clinical biomarkers.