Deep Sequencing MicroRNAs from Extracellular Membrane Vesicles Revealed the Association of the Vesicle Cargo with Cellular Origin.

Extracellular membrane vesicles (EVs) have emerged as potential candidates for diagnostics and therapeutics. We have previously reported that keratinocytes release three types of EVs into the extracellular environment. Importantly, those EVs contain a large number of microRNAs (miRNAs) as cargo. In this study, we examined the expression level of keratinocyte-derived EV miRNAs, their target genes and potential functions. Next generation sequencing results showed that over one hundred miRNAs in each EV subtype exhibited greater than 100 reads per million (RPM), indicating a relatively high abundance. Analysis of the miRNAs with the highest abundance revealed associations with different keratinocyte cell sources. For instance, hsa-miR-205 was associated with the HaCaT cells whereas hsa-miR-21, hsa-miR-203, hsa-miR-22 and hsa-miR-143 were associated with human primary dermal keratinocytes (PKCs). Additionally, functional annotation analysis of genes regulated by those miRNAs, especially with regard to biological processes, also revealed cell-type-specific associations with either HaCaTs or PKCs. Indeed, EV functional effects were related to their parental cellular origin; specifically, PKC-derived EVs influenced fibroblast migration whereas HaCaT-derived EVs did not. In addition, the data in this current study indicates that keratinocyte-derived EVs and/or their cargoes have potential applications for wound healing.