Oral swirl samples - a robust source of microRNA protected by extracellular vesicles

BackgroundMicroRNAs are small non-coding RNAs which are dysregulated in disease states, such as oral cancer. Extracellular vesicles, a potential source of microRNA, are found in saliva. ObjectiveTo demonstrate that a quantifiable amount of microRNA can be isolated from oral swirl samples. Additionally, we hypothesized that extracellular vesicles may protect contained microRNA from degradation in these samples. MethodA polyethylene glycol-based precipitation was used for extracellular vesicle enrichment of oral swirl samples. Comparison was made between samples treated with and without RNase. Further, samples from three subjects were exposed to a range of conditions over 7days and assessed for presence of microRNA by reverse-transcription quantitative PCR. Extracellular vesicles from samples were identified under transmission electron microscopy. ResultsAn adequate quantity of microRNA for qPCR analysis was extractable from samples despite exposure to conditions under which degradation of RNA would be expected. ConclusionA technique was developed to isolate an adequate quantity of microRNA for analysis from oral swirl samples. Extracellular vesicle-associated microRNA may be protected from degradation. This technique moves towards chairside application of translational microRNA research in the field of oral cancer prognostics.