An enzyme-based system for extraction of small extracellular vesicles from plants

Plant-derived nanovesicles (NVs) and extracellular vesicles (EVs) are the next generation of nanocarrier platforms for biotherapeutics and drug delivery. EVs exist not only in the extracellular space, but also within the cell wall. Due to the limitations of existing isolation methods, the EVs extraction efficiency is low, and a large amount of plant material is wasted, which is of concern for rare and expensive medicinal plants. We proposed and validated a novel method for isolation of plant EVs by enzyme degradation of the plant cell wall to release the EVs. The released EVs can easily be collected. The new method was used for extraction of EVs from the roots of Morinda officinalis (MOEVs). For comparison, nanoparticles from the roots (MONVs) were extracted using the grinding method. The new method yielded a greater amount of MOEVs, and the vesicles had a smaller diameter compared to MONVs. Both MOEVs and MONVs were readily absorbed by endothelial cells without cytotoxic effect and promoted the expression of miR-155. The promotion of miR-155 by MOEVs was dose-dependent. More importantly, we found that MOEVs and MONVs were enriched toward bone tissue. These results support our hypothesis that EVs in plants could be efficiently extracted by enzymatic cell wall digestion and confirm the potential of MOEVs as therapeutic agents and drug carriers.