The overall goal of this proposal is to define the role of edible plant exosomal non-coding small RNA (nc-sRNA) in the prevention of gut inflammation using the dextran sulfate sodium (DSS) induced colitis and three other gut inflammatory related mouse models. Although evidence is supportive of the beneficial effects for most edible plants taken as part of the diet, the evidence that specific plant-based supplements are beneficial is controversial, and the underlying mechanisms are not clear. The challenge is to isolate and characterize the biological activities of the essential functional unit contained in specific naturl products to determine if and how it's cellular and molecular effects on the host can be used in a beneficial manner. Our recently published data (1-5) indicates that exosome-like nanoparticles (ELNs) present in a number of edible plants including grapefruit and ginger have anti-inflammatory properties. Mice fed grapefruit ELNs (FELNs) are protected against DSS induced mouse colitis. Up take of FELNs by intestinal macrophages inhibits the release of IL-1? and IL-6 and the induction of HO-1 and IL-10 expression. Our preliminary data further indicate that FELNs carry high levels of specific nc-sRNA that inhibit the induction of proinflammatory cytokines by targeting intestinal macrophages. The nc-sRNA is associated with inactivation of macrophage miR155. A specific FELN nc-sRNA complexed with naringin binds to miR155 and subsequently prevents miR155 binding to 3-UTRs of certain anti-inflammatory genes, thus inhibiting the induction of proinflammatory cytokines. We have also demonstrated that ginger ELN nc-sRNAs promotes the production of IL-10 in lamina propria macrophages under steady-state as well as inflammatory conditions. Therefore, we hypothesize that plant ELNs carrying the nc-sRNA bioactive complex are taken up by intestinal macrophages and subsequently bind to inflammatory microRNAs, resulting in inhibition of induction of chronic inflammation cytokines, thereby preventing chronic intestinal inflammation. Our hypothesis will be tested in vitro and in vivo to determine: (1) whether FELN taken up by intestinal macrophages leads to induction of tolerant dendritic cells (DCs) through nc-sRNA-155 mediated anti-inflammatory effects since DCs are critical for gut immune tolerance and homeostasis through cross-talk with intestinal macrophages; (2) the factors that regulate sorting of anti-inflammatory nc-sRNA-155 into macrophage exosomes; and (3) which ginger ELNs nc-sRNA(s) are required for induction of anti- inflammatory IL-10 expressed in macrophages. Demonstration of the ELNs complex targeting to gut inflammatory cells would be a significant step forward in the understanding of how the plant kingdom interacts with the mammalian species to regulate anti-inflammatory responses through ELNs. The data generated should provide a foundation for selecting specific ELNs from different types of plants for personalized complementary medicine for patients and determine whether oral administration of a customized exosome isolated from different plants will have a synergistic/additive effect on prevention or treatment of disease.
Although evidence is supportive of the beneficial effects for most edible plants taken as part of the diet, molecule mechanisms underlying beneficial of edible plants and extracts for sustaining health is not clear. The studies that we have accomplished to date suggest that edible plant exosome-like nanoparticles encapsulated with non-coding small RNAs that binds to miRNAs prevent mouse colitis- standard mouse models for studying Crohn's disease. The focus of this application is to further characterize these mechanisms and then to determine whether targeting of these mechanisms is through communication with different subsets of miRNAs expressed in the intestinal macrophages, and this will also allow for further investigations as to how interspecies communication takes place via plant derived exosomes.
