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Small RNA deep sequencing reveals a distinct miRNA signature released in exosomes from prion-infected neuronal cells.

ABSTRACT: Prion diseases are transmissible neurodegenerative disorders affecting both humans and animals. The cellular prion protein, PrP(C), and the abnormal infectious form, PrP(Sc), are found associated with exosomes, which are small 50-130 nm vesicles released from cells. Exosomes also contain microRNAs (miRNAs), a class of non-coding RNA, and have been utilized to identify miRNA signatures for diagnosis of disease. While some miRNAs are deregulated in prion-infected brain tissue, the role of miRNA in circulating exosomes released during prion disease is unknown. Here, we investigated the miRNA profile in exosomes released from prion-infected neuronal cells. We performed the first small RNA deep sequencing study of exosomes and demonstrated that neuronal exosomes contain a diverse range of RNA species including retroviral RNA repeat regions, messenger RNA fragments, transfer RNA fragments, non-coding RNA, small nuclear RNA, small nucleolar RNA, small cytoplasmic RNA, silencing RNA as well as known and novel candidate miRNA. Significantly, we show that exosomes released by prion-infected neuronal cells have increased let-7b, let-7i, miR-128a, miR-21, miR-222, miR-29b, miR-342-3p and miR-424 levels with decreased miR-146 a levels compared to non-infected exosomes. Overall, these results demonstrate that circulating exosomes released during prion infection have a distinct miRNA signature that can be utilized for diagnosis and understanding pathogenic mechanisms in prion disease.

SUBMITTER: Bellingham SA

PROVIDER: S-EPMC3505968 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Small RNA deep sequencing reveals a distinct miRNA signature released in exosomes from prion-infected neuronal cells.

Bellingham Shayne A SA Coleman Bradley M BM Hill Andrew F AF

Nucleic acids research 20120910 21

Prion diseases are transmissible neurodegenerative disorders affecting both humans and animals. The cellular prion protein, PrP(C), and the abnormal infectious form, PrP(Sc), are found associated with exosomes, which are small 50-130 nm vesicles released from cells. Exosomes also contain microRNAs (miRNAs), a class of non-coding RNA, and have been utilized to identify miRNA signatures for diagnosis of disease. While some miRNAs are deregulated in prion-infected brain tissue, the role of miRNA in ...[more]

PMID: 22965126

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Project description:BackgroundMacrophages infected with Mycobacterium tuberculosis (M.tb) are known to be refractory to IFN-? stimulation. Previous studies have shown that M.tb express components such as the 19-kDa lipoprotein and peptidoglycan that can bind to macrophage receptors including the Toll-like receptor 2 resulting in the loss in IFN-? responsiveness. However, it is unclear whether this effect is limited to infected macrophages. We have previously shown that M.tb-infected macrophages release exosomes which are 30-100 nm membrane bound vesicles of endosomal origin that function in intercellular communication. These exosomes contain mycobacterial components including the 19-kDa lipoprotein and therefore we hypothesized that macrophages exposed to exosomes may show limited response to IFN-? stimulation.Methodology/principal findingsExosomes were isolated from resting as well as M.tb-infected RAW264.7 macrophages. Mouse bone marrow-derived macrophages (BMMØ) were treated with exosomes +/- IFN-?. Cells were harvested and analyzed for suppression of IFN-? responsive genes by flow cytometry and real time PCR. We found that exosomes derived from M.tb H37Rv-infected but not from uninfected macrophages inhibited IFN-? induced MHC class II and CD64 expression on BMMØ. This inhibition was only partially dependent on the presence of lipoproteins but completely dependent on TLR2 and MyD88. The exosomes isolated from infected cells did not inhibit STAT1 Tyrosine phosphorylation but down-regulated IFN-? induced expression of the class II major histocompatibility complex transactivator; a key regulator of class II MHC expression. Microarray studies showed that subsets of genes induced by IFN-? were inhibited by exosomes from H37Rv-infected cells including genes involved in antigen presentation. Moreover, this set of genes partially overlapped with the IFN-?-induced genes inhibited by H37Rv infection.ConclusionsOur study suggests that exosomes, as carriers of M.tb pathogen associated molecular patterns (PAMPs), may provide a mechanism by which M.tb may exert its suppression of a host immune response beyond the infected cell.

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Small RNA deep sequencing reveals a distinct miRNA signature released in exosomes from prion-infected neuronal cells.

Publications

Small RNA deep sequencing reveals a distinct miRNA signature released in exosomes from prion-infected neuronal cells.

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