Exosome-like Nanovesicles Isolated from Citrus limon L. Exert Antioxidative Effect

Background: Exosome-like nanovesicles are biological nanostructures mediating cell-tocell communication and capable to load selected cargos also in the interaction among different species. Objective: We aimed to explore the content of exosome-like nanovesicles derived from Citrus limon L. and to analyze the effects of their uptake on human cells. Method: We isolated exosome-like nanovesicles from Citrus limon L. juice (EXO-CLs) by differential centrifugation. EXO-CLs were analyzed for short RNA content by advanced sequencing technologies, and for ascorbic acid (vitamin C) and citrate content by enzymatic assays. EXO-CLs anti-oxidant and pro-differentiative potential was evaluated in vitro on mesenchymal stromal cells (MSC), a common tool for regenerative strategies for several human tissues. Results: We showed that EXO-CLs carry detectable amounts of citrate and vitamin C and, although it was not possible to identify specific miRNAs, we detected short RNA sequences (20-30 bp) with unknown functions and with different distribution size in respect to whole Citrus limon L. juice. In vitro, EXO-CLs were uptaken by MSC and had a significant protective effect against oxidative stress. Furthermore, regarding the potential benefit for human bone health, we found that EXO-CLs modulate MSC differentiation versus the osteogenic lineage. Conclusion: We demonstrated that incubation with EXO-CLs exert antioxidant activity in human cells. This is most likely due to the direct delivery and uptake of micronutrients by human cells that are well preserved inside the nanovesicle membrane, including the unstable vitamin C. Based on our results, we speculate that fruit-derived nanovesicles have the potential to mediate interspecies influence after food intake. Keywords: Citrus limon L., exosome-like nanovesicles, mesenchymal stromal cells, oxidative stress, ascorbic acid, short sequence RNAs.