A fraction of diet-derived microRNAs present in plant extracellular vesicles remain detectable after gastrointestinal digestion and shows epithelial uptake in a CaCo-2 cell model

Diet constitutes a source of exogenous miRNAs that are detectable in humans. Source, stability to digestion, and cellular uptake of diet-derived miRNAs are debated topics. Here, we studied the stability of cauliflower miRNAs to cooking (100 °C, 20 min) and gastrointestinal digestion (static INFOGEST 2.0), their possible cellular uptake/secretion by CaCo-2 cells, and the role of plant extracellular vesicles (PEVs). miRNAs were assessed by qPCR. The role of PEVs was evaluated via dynamic light scattering, electron microscopy, and immunoblotting. Most RNA was degraded after digestion (99.1%). However, a fraction of miRNAs in PEVs (bol-miR172a, bol-miR156a, bol-miR164b, bol-miR1030i) remained detectable (0.05-0.24%). PEVs were also detected after digestion, which caused aggregation and decreased particle numbers. Finally, nano-encapsulation, concentration and exposure time appeared associated with miRNA uptake (40-fold compared with control). Data for secretion was inconclusive. Overall, we showed that a small fraction of miRNAs associated with PEVs remained detectable following digestion.