Plant miRNAs, a group of 19 -24 nt non -coding RNAs from plant foods, were recently found to be of immunomodulatory and nutritional effects on mammalian and human bodies. However, how do the miRNAs survive gastrointestinal (GI) environment and how the stable miRNAs are absorbed, which serve the basis for their biological functions were not unraveled. Here, we investigated the stabilities of six typical plant miRNAs in simulated gastric and intestinal environments, and the absorption mechanisms by Caco -2 cells. The results showed that the miRNAs can survive th e environment with certain concentrations. The mixture of food ingredients enhanced the stabilities of the plant miRNAs in the gastric conditions, while ... More
Plant miRNAs, a group of 19 -24 nt non -coding RNAs from plant foods, were recently found to be of immunomodulatory and nutritional effects on mammalian and human bodies. However, how do the miRNAs survive gastrointestinal (GI) environment and how the stable miRNAs are absorbed, which serve the basis for their biological functions were not unraveled. Here, we investigated the stabilities of six typical plant miRNAs in simulated gastric and intestinal environments, and the absorption mechanisms by Caco -2 cells. The results showed that the miRNAs can survive th e environment with certain concentrations. The mixture of food ingredients enhanced the stabilities of the plant miRNAs in the gastric conditions, while 2' - O -methyl modification protects the miRNAs in intestinal juice. The stabilities of the miRNAs vary significantly in the environment and are related to their secondary structures. The stable plant miRNAs can be absorbed by Caco -2 cells via clathrin and caveolin -mediated endocytosis. Uptake of the miRNAs were sequence -dependent, facilitated by NACh and TLR9, two typical receptors on cell membrane. The results suggest that some of plant miRNAs are stable in the mimic GI environment, and can be absorbed by Caco -2 cells, underlying the potential of their cross -kingdom regulation effects.
