RPRH: a web-based tool for the inference of potential roles of plant microRNAs in human body

ABSTRACTRecently, increasing studies reported that plant microRNAs (miRNAs) from food could be absorbed through gastrointestinal tract to regulate the physiological processes of animals. These novel cross-kingdom regulatory roles of plant miRNAs open a new field in miRNA study and drug discovery, but the lack of corresponding bioinformatics tools limit the development of this field. In this study, we built a web-based tool, RPRH (Role of Plant microRNA in Human), to infer the potential roles of plant miRNAs in human and to profile the landscape of all documented plant miRNAs regulatory functions in human. Totally, RPRH included 10414 miRNAs from 82 plant species and 18062 annotation terms like diseases, pathway, gene ontology (GO), and drugs. RPRH represents a bioinformatics resource for further investigation of cross-kingdom regulations of plant miRNAs.Availabilityhttp://www.rnanut.net/rprh/

Common Variants of the Plant microRNA-168a Exhibit Differing Silencing Efficacy for Human Low-Density Lipoprotein Receptor Adaptor Protein 1 (LDLRAP1)

Background: The discovery that a plant microRNA (miRNAs) from rice (Oryza sativa miR168a) can modify post-transcriptional expression of the mammalian. Low-Density Lipoprotein Receptor Adaptor Protein 1 (LDLRAP1) gene highlights the potential for cross-kingdom miRNAmRNA interactions. Objective: To investigate whether common variants of the conserved miR168a family have the capability for similar cross-kingdom regulatory functions, we selected sequences from three dietary plant sources: rice (Oryza sativa), tomato (Solanum lycopersicum), apple (Malus domestica) and compared their ability to regulate human LDLRAP1 expression. Methods: Target prediction software intaRNA and RNAhybrid were used to analyze and calculate the energy and alignment score between the miR168a variants and human LDLRAP1 mRNA. An in vitro cell-based Dual-Luciferase® Reporter Assay (pmirGLO, Promega), was then used to validate the miRNA-mRNA interaction experimentally. Results: Computational analyses revealed that a single nucleotide difference at position 14 (from the 5’ end of the miRNA) creates a G:U wobble in the miRNA-mRNA duplex formed by tomato and apple miR168a variants. This G:U wobble had only a small effect on the free energy score (-33.8–34.7 kcal/mol). However, despite reasonable hybridization energy scores (<-20 kcal/mol) for all miR168a variants, only the rice miR168a variant lacking a G:U wobble significantly reduced LDLRAP1 transcript expression by 25.8 + 7.3% (p<0.05), as measured by relative luciferase activity. Conclusion: In summary, single nucleotide differences at key positions can have a marked influence on regulatory function despite similar predicted energy scores and miRNA-mRNA duplex structures.