Plant MicroRNAs—Novel Players in Natural Medicine?

Abstract

MicroRNAs (miRNAs) represent a class of small non-coding RNAs that act as efficient gene expression regulators and thus play many important roles in living organisms. Due to their involvement in several known human pathological and pathogenic states, miRNA molecules have become an important issue in medicine and gained the attention of scientists from the pharmaceutical industry. In recent few years, a growing number of studies have provided evidence that miRNAs may be transferred from one species to another and regulate gene expression in the recipients’ cells. The most intriguing results revealed that stable miRNAs derived from food plants may enter the mammals’ circulatory system and, after reaching the target, inhibit the production of specific mammalian protein. Part of the scientific community has perceived this as an attractive hypothesis that may provide a foundation for novel therapeutic approaches. In turn, others are convinced about the “false positive” effect of performed experiments from which the mentioned results were achieved. In this article, we review the recent literature that provides evidence (from both fronts) of dietary, plant miRNA uptake and functionality in various consumers. Additionally, we discuss possible miRNA transport mechanisms from plant food sources to human cells.

Small RNAs in eucaryotes: new clues for amplifying microRNA benefits

“…In particular, rice miR168a has been suggested to target the mRNA of the low-density lipoprotein receptor adaptor protein 1, and rice-fed mice showed a reduction in receptor expression in blood and liver. Evidences also indicated that the integration of exogenous miR168 from plants can contribute to modulate dyslipidemia in mammals [64,68]. The presence of rice miRNAs in human plasma was further supported by Wang, who using next generation small RNA sequencing datasets of human serum samples, identified several exogenous small RNA species from gut microbiota and plant species [69].…”

Integrated Analysis of Mouse and Human Gastric Neoplasms Identifies Conserved microRNA Networks in Gastric Carcinogenesis

“…There are a number of recent advances in approaches using miRNAs for cancer treatment, 53,54 including early efforts at developing edible plants that express miRNAs for treatment of human diseases. 55 In this context, approaches that reconstitute MIR143-3p could have an impact on the prevention and or treatment of GC.…”

Extracellular microRNAs initiate immunostimulation via activating toll-like receptor signaling pathways

“…Following the discovery of cross-kingdom regulation mediated by plant miRNAs in mammalian tissues and cells [3,33], an increasing body of literature has shown that exogenous miRNAs derived from various species, including plants and viruses, play a critical role in modulating mammalian cell function [34][35][36]. Although these exogenous miRNAs execute their biological function in the recipient cells mainly through base-pairing the transcript of target genes in a manner of endogenous miRNA [34,35], certain exogenous miRNAs that contain the TLR-binding GU-rich motif can also directly bind to intracellular TLRs or cell surfaces, leading to activation of TLR-mediated immune responses.…”