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

ABSTRACT: Background: A 2017 study reported that "Plant miRNAs found in human circulating system provide evidences of cross kingdom RNAi". Analysis of two human blood plasma sequencing datasets was said to provide evidence for uptake of plant miRNAs into human plasma. The results were also purportedly inconsistent with contamination. Methods: Sequences from public datasets and miRNA databases were compared with results downloaded from the website of the reporting journal. Results: Only one putative plant miRNA ("peu-MIR2910) mapped consistently above background, and this sequence is found with 100% identity in a human rRNA. Several other rarer but consistently mapped putative plant miRNAs also have 100% or near 100% matches to human transcripts or genomic sequences, and some do not appear to map to plant genomes at all. Conclusions: Reanalysis of public data suggests that dietary plant xenomiR uptake is not supported, but instead confirms previous findings that detection of rare plant miRNAs in mammalian sequencing datasets is artifactual. Some putative plant miRNAs, including MIR2910 and MIR2911, may represent human sequence contamination or other artifacts in plant studies, emphasizing the need for rigorous controls and data filtering strategies when assessing possible xenomiRNAs.

SUBMITTER: Witwer KW

PROVIDER: S-EPMC5904727 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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

Witwer Kenneth W KW

F1000Research 20180228

Background: A 2017 study reported that "Plant miRNAs found in human circulating system provide evidences of cross kingdom RNAi". Analysis of two human blood plasma sequencing datasets was said to provide evidence for uptake of plant miRNAs into human plasma. The results were also purportedly inconsistent with contamination. Methods: Sequences from public datasets and miRNA databases were compared with results downloaded from the website of the reporting journal. Results: Onl ...[more]

PMID: 29744036

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Project description:We hereby present the first descriptions of human-invasive infections caused by Escherichia marmotae, a recently described species that encompasses the former "Escherichia cryptic clade V." We describe four cases, one acute sepsis of unknown origin, one postoperative sepsis after cholecystectomy, one spondylodiscitis, and one upper urinary tract infection. Cases were identified through unsystematic queries in a single clinical lab over 6 months. Through genome sequencing of the causative strains combined with available genomes from elsewhere, we demonstrate Es. marmotae to be a likely ubiquitous species containing genotypic virulence traits associated with Escherichia pathogenicity. The invasive isolates were scattered among isolates from a range of nonhuman sources in the phylogenetic analyses, thus indicating inherent virulence in multiple lineages. Pan genome analyses indicate that Es. marmotae has a large accessory genome and is likely to obtain ecologically advantageous traits, such as genes encoding antimicrobial resistance. Reliable identification might be possible by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), but relevant spectra are missing in commercial databases. It can be identified through 16S rRNA gene sequencing. Escherichia marmotae could represent a relatively common human pathogen, and improved diagnostics will provide a better understanding of its clinical importance. IMPORTANCE Escherichia coli is the most common pathogen found in blood cultures and urine and among the most important pathogenic species in the realm of human health. The notion that some of these isolates are not Es. coli but rather another species within the same genus may have implications for what Es. coli constitutes. We only recently have obtained methods to separate the two species, which means that possible differences in important clinical aspects, such as antimicrobial resistance rates, virulence, and phylogenetic structure, may exist. We believe that Es. marmotae as a common pathogen is new merely because we have not looked or bothered to distinguish between the thousands of invasive Escherichia passing through microbiological laboratories each day.

Dataset Information

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

Publications

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

Similar Datasets

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