Abstract:Exosomes are released by most cells to the extracellular environment and are involved in cell-to-cell communication. Exosomes contain specific repertoires of mRNAs, microRNAs (miRNAs) and other non-coding RNAs that can be functionally transferred to recipient cells. However, the mechanisms that control the specific loading of RNA species into exosomes remain unknown. Here we describe sequence motifs present in miRNAs that control their localization into exosomes. The protein heterogeneous nuclear ribonucleopro… Show more
“…Although circRNPs appear to be distinct RNP complexes, small circRNAs can in general bind fewer proteins than very large circRNAs; for example, GSE1, one of the shortest circRNAs analysed here, assembles into a relatively small RNP (see Figure 3). We note that, in addition to the circRNA size, there are likely other sorting and selection determinants, for example, particular sequence motifs, as shown for miRNAs [34]. …”
Circular RNAs (circRNAs) are a novel class of noncoding RNAs present in all eukaryotic cells investigated so far and generated by a special mode of alternative splicing of pre-mRNAs. Thereby, single exons, or multiple adjacent and spliced exons, are released in a circular form. CircRNAs are cell-type specifically expressed, are unusually stable, and can be found in various body fluids such as blood and saliva. Here we analysed circRNAs and the corresponding linear splice isoforms from human platelets, where circRNAs are particularly abundant, compared with other hematopoietic cell types. In addition, we isolated extracellular vesicles from purified and in vitro activated human platelets, using density-gradient centrifugation, followed by RNA-seq analysis for circRNA detection. We could demonstrate that circRNAs are packaged and released within both types of vesicles (microvesicles and exosomes) derived from platelets. Interestingly, we observed a selective release of circRNAs into the vesicles, suggesting a specific sorting mechanism. In sum, circRNAs represent yet another class of extracellular RNAs that circulate in the body and may be involved in signalling pathways. Since platelets are essential for central physiological processes such as haemostasis, wound healing, inflammation and cancer metastasis, these findings should greatly extend the potential of circRNAs as prognostic and diagnostic biomarkers.
“…Although circRNPs appear to be distinct RNP complexes, small circRNAs can in general bind fewer proteins than very large circRNAs; for example, GSE1, one of the shortest circRNAs analysed here, assembles into a relatively small RNP (see Figure 3). We note that, in addition to the circRNA size, there are likely other sorting and selection determinants, for example, particular sequence motifs, as shown for miRNAs [34]. …”
Circular RNAs (circRNAs) are a novel class of noncoding RNAs present in all eukaryotic cells investigated so far and generated by a special mode of alternative splicing of pre-mRNAs. Thereby, single exons, or multiple adjacent and spliced exons, are released in a circular form. CircRNAs are cell-type specifically expressed, are unusually stable, and can be found in various body fluids such as blood and saliva. Here we analysed circRNAs and the corresponding linear splice isoforms from human platelets, where circRNAs are particularly abundant, compared with other hematopoietic cell types. In addition, we isolated extracellular vesicles from purified and in vitro activated human platelets, using density-gradient centrifugation, followed by RNA-seq analysis for circRNA detection. We could demonstrate that circRNAs are packaged and released within both types of vesicles (microvesicles and exosomes) derived from platelets. Interestingly, we observed a selective release of circRNAs into the vesicles, suggesting a specific sorting mechanism. In sum, circRNAs represent yet another class of extracellular RNAs that circulate in the body and may be involved in signalling pathways. Since platelets are essential for central physiological processes such as haemostasis, wound healing, inflammation and cancer metastasis, these findings should greatly extend the potential of circRNAs as prognostic and diagnostic biomarkers.
“…In fact, the largest grouping of proteins unique to A1-EVs (Figure 7(b)) is involved in protein metabolism (31%), and includes extracellular matrix remodelling [22,48] as well as proteosomal and ribosomal subunit factors (Figure 7(c,d)). The second highest proportion of proteins unique to A1-EVs are nucleic acid metabolism factors, with particular enrichment of heterogeneous nuclear ribonucleoprotein family members, responsible for RNA shuttling (Figure 7(d)) [49,50]. Similar protein profiles were seen using mass spectrometry and Western blot with A1-EVs enriched by either UFC or precipitation methods (Supplemental Figure 3 and Supplemental Tables 1 and 2).10.1080/20013078.2018.1456888-F0007Figure 7.EV protein profiles as determined by mass spectrometry.…”
Newts can regenerate amputated limbs and cardiac tissue, unlike mammals which lack broad regenerative capacity. Several signaling pathways involved in cell proliferation, differentiation and survival during newt tissue regeneration have been elucidated, however the factors that coordinate signaling between cells, as well as the conservation of these factors in other animals, are not well defined. Here we report that media conditioned by newt limb explant cells (A1 cells) protect mammalian cardiomyocytes from oxidative stress-induced apoptosis. The cytoprotective effect of A1-conditioned media was negated by exposing A1 cells to GW4869, which suppresses the generation of extracellular vesicles (EVs). A1-EVs are similar in diameter (~100–150 nm), structure, and share several membrane surface and cargo proteins with mammalian exosomes. However, isolated A1-EVs contain significantly higher levels of both RNA and protein per particle than mammalian EVs. Additionally, numerous cargo RNAs and proteins are unique to A1-EVs. Of particular note, A1-EVs contain numerous mRNAs encoding nuclear receptors, membrane ligands, as well as transcription factors. Mammalian cardiomyocytes treated with A1-EVs showed increased expression of genes in the PI3K/AKT pathway, a pivotal player in survival signaling. We conclude that newt cells secrete EVs with diverse, distinctive RNA and protein contents. Despite ~300 million years of evolutionary divergence between newts and mammals, newt EVs confer cytoprotective effects on mammalian cardiomyocytes.
“…are enriched or underrepresented in EVs compared to their respective parent cells [36][37][38][39][40][41]. Based on these observations it is generally accepted that the composition of EVs is, at least partially, actively regulated by the parent cell [42], albeit that the mechanisms and associated key players regulating this cargo sorting remain largely elusive to date [38,[43][44][45][46]. The overall EV configuration (i.e.…”
Section: Biogenesis Cargo Loading and Compositionmentioning
confidence: 99%
“…Villarroya-Beltri and colleagues showed that miRNAs containing a GGAG sequence were overrepresented in primary T lymphoblast EVs. They suggest that this sequence is selectively recognized by the RNA binding protein heterogeneous nuclear ribonucleoproteins A2/B1 (hnRNPA2B1) and subsequently drives incorporation into EVs [38].…”
Section: Loading Evs With a Therapeutic Cargomentioning
During the past two decades, extracellular vesicles (EVs) have been identified as important mediators of intercellular communication, enabling the functional transfer of bioactive molecules from one cell to another. Consequently, it is becoming increasingly clear that these vesicles are involved in many (patho)physiological processes, providing opportunities for therapeutic applications. Moreover, it is known that the molecular composition of EVs reflects the physiological status of the producing cell and tissue, rationalizing their exploitation as biomarkers in various diseases. In this review the composition, biogenesis and diversity of EVs is discussed in a therapeutic and diagnostic context. We describe emerging therapeutic applications, including the use of EVs as drug delivery vehicles and as cell-free vaccines, and reflect on future challenges for clinical translation. Finally, we discuss the use of EVs as a biomarker source and highlight recent studies and clinical successes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
