Plant miRNAs found in human circulating system provide evidences of cross kingdom RNAi

Abstract

BackgroundEmerging evidence indicates that plant miRNAs can present within human circulating system through dietary intake and regulate human gene expression. Hence we deduced that comestible plants miRNAs can be identified in the public available small RNA sequencing data sets.ResultsIn this study, we identified abundant plant miRNAs sequences from 410 human plasma small RNA sequencing data sets. One particular plant miRNA miR2910, conserved in fruits and vegetables, was found to present in high relative amount in the plasma samples. This miRNA, with same 6mer and 7mer-A1 target seed sequences as hsa-miR-4259 and hsa-miR-4715-5p, was predicted to target human JAK-STAT signaling pathway gene SPRY4 and transcription regulation genes.ConclusionsThrough analysis of public available plasma small RNA sequencing data, we found the supporting evidence for the plant miRNAs cross kingdom RNAi within human circulating system.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3502-3) contains supplementary material, which is available to authorized users.

Dietary plant miRNAs as an augmented therapy: cross-kingdom gene regulation

“…miR2910 from Populus euphratica was detected to be more abundant than most of the human miRNAs in the samples. miR2910 was identified in human plasma and targets Sprouty RTK Signaling Antagonist 4 (SPRY4) gene of the Janus kinase/ signal transducers and activators of transcription (JAK-STAT) signaling pathway and transcription regulation gene indicating its role in human diseases [37]. Earlier reported miR168 [31] and miR159 [34] were also detected in the considered human samples even in small amount and given supporting evidence of the reports (Table 1).…”

“…After reaching to different tissues, these plant miRNAs modulate the expression of their target genes (Fig 2). The plant miRNAs has also been detected in all biofluids such as serum [31,32] and plasma [37] through secretion. MiR2911 from honeysuckle has also been detected in mouse micro vesicles (MVs) of peripheral blood in associated form with AGO2 complex after passing through GI tract [35].…”

Alternative miRNAs? Human sequences misidentified as plant miRNAs in plant studies and in human plasma

“…Counts were presented as reads per million mapped reads (rpm) 20 . In contrast, Liu et al appear to have reported total mapped reads in their data table 18 . Yuan et al also set an expression cutoff of 32 rpm (log2 rpm of 5 or above).…”

“…Plant mapping results from Liu et al 18 (total mapped counts) were downloaded from the BMC Genomics website. Accession numbers of sequencing datasets were checked against the publications of Ninomiya et al 19 and Yuan et al 20 , as well as the Sequence Read Archive ( SRA ).…”

“…Studies of organisms with no exposure to plants have also found evidence of the same types of apparent plant contamination that plague some measurements of human samples 8 , 17 . Liu et al 18 mapped sequencing data from two studies of human plasma and other samples 19 , 20 to various plant genomes using a 2010 plant miRNA database, PMRD 21 , concluding that previous reports of dietary xenomiR transfer are supported. In this brief report, these results are examined critically.…”