Profiling tumor bacteria: Bacteria are well-known residents in human tumors, but whether their presence is advantageous to the tumors or to the bacteria themselves has been unclear. As an initial step toward addressing this question, Nejman et al. produced an exhaustive catalog of the bacteria present in more than 1500 human tumors representing seven different tumor types (see the Perspective by Atreya and Turnbaugh). They found that the bacteria within tumors were localized within both cancer cells and immune cells and that the bacterial composition varied according to tumor type. Certain biologically plausible associations were identified. For example, breast cancer subtypes characterized by increased oxidative stress were enriched in bacteria that produce mycothiol, which can detoxify reactive oxygen species. Science , this issue p. 973 ; see also p. 938

Plant-derived exosome-like nanovesicles (EPDENs) have recently been isolated and evaluated as potential bioactive nutraceutical biomolecules. It has been hypothesized that EPDENs may exert their activity on mammalian cells through their specific cargo. In this study, we isolated and purified EPDENs from the strawberry juice of Fragaria x ananassa (cv. Romina), a new cultivar characterized by a high content of anthocyanins, folic acid, flavonols, and vitamin C and an elevated antioxidant capacity. Fragaria-derived EPDENs were purified by a series of centrifugation and filtration steps. EPDENs showed size and morphology similar to mammalian extracellular nanovesicles. The internalization of Fragaria-derived EPDENs by human mesenchymal stromal cells (MSCs) did not negatively affect their viability, and the pretreatment of MSCs with Fragaria-derived EPDENs prevented oxidative stress in a dose-dependent manner. This is possibly due to the presence of vitamin C inside the nanovesicle membrane. The analysis of EPDEN cargo also revealed the presence of small RNAs and miRNAs. These findings suggest that Fragaria-derived EPDENs may be considered nanoshuttles contained in food, with potential health-promoting activity.

Background. Exosome-like nanovesicles are biological nanostructures mediating cell-to-cell 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-CL) by differential centrifugation. EXOCL were analyzed for short RNA content by advanced sequencing technologies, and for ascorbic acid (vitamin C) and citrate content by enzymatic assays. EXO-CL 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-CL 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-CL 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-CL modulate MSC differentiation versus the osteogenic lineage. Conclusion. We demonstrated that incubation with EXO-CL exerts 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.