Project description:Background: Acute coronary syndromes (ACS) are associated with aberrant gene expression and epigenetic mechanisms. In particular, de novo DNA methylation is typically linked to gene silencing, but its role in heart disease remains not fully understood. Extracellular vesicles (EVs) are active components in cellular communication for their ability to carry a plethora of signalling biomolecules, thus representing a promising new diagnostic/therapeutic approach in cardiovascular diseases (CVDs). Indeed, there is the need of novel biomarkers for ACS prediction and timely detection. Purpose: We hypothesized that specific epigenetic signals can be carried by EVs. In this regard, we isolated and characterized circulating EVs from ACS patients and evaluated their potential role to influence DNA methylation in target cells. Methods: Circulating EVs were recovered, by ultracentrifugation, from plasma samples of 19 ACS patients and 50 healthy subjects (HS). Nanoparticle tracking analysis (NTA) and western blot (WB) were used to confirm the EVs integrity and purity. Peripheral blood mononuclear cells (PBMCs) of volunteer donors were treated with both ACS and HS derived EVs and genomic DNA was extracted to perform epigenome wide analysis through Reduced Representation Bisulfite Sequencing. ShinyGO, PANTHER, and STRING tools were interrogated to perform GO and PPI network analyses. Flow Cytometry, qRT-PCR, and WB analysis were also performed to evaluate and validate both intra-vesicular and intra-cellular signals. Results: Plasma ACS-derived EVs showed a significant up-regulation of DNA methyltransferases (DNMTs) gene expression levels as compared to HS (P<0.001). Specifically, de novo methylation transcripts, as DNMT3A and DNMT3B were significantly increased in plasma ACS-EVs. DNA methylation analysis of PBMCs from volunteer donors treated with HS- and ACS-derived EVs showed that RNF166 and CCND3 genes resulted the most hyper- and hypo-methylated, respectively, after by ACS-EV treatment. In addition, PPI network analysis specifically evidenced the subnetwork with SRC, as a hub gene, connecting it to NOTCH1, FOXO3, CDC42, IKBKG, RXRA, DGKG, known as important genes already involved in the onset of CVDs. Surprising, other novel genes, BAIAP2, SYP, CHL1, and SHB, which were hypomethylated, were found significantly overexpressed in PBMCs (P<0.005), underlying the fundamental modulating properties of EV cargo in atherosclerosis. Conclusions: These findings support the significant role of ACS plasma-derived EVs, inducing de novo DNA methylation signals, and modulating specific signaling pathways in target cells.

Project description:Introduction: Cell-derived extracellular vesicles ([EVs], i.e., exosomes and microparticles) have been reported to mediate the cardioprotective effects of stem cells. However, a head-to-head comparison of their effects with those of the cells from which they derive has not been reported. Hypothesis: The effects of the EV content of human embryonic stem cell (hESC)-derived cardiac progenitors may be equivalent to those of the parent cells. Methods: Two series of immunodeficient (nude) mice underwent permanent coronary artery ligation. Three weeks later, those with an echocardiographically-determined LV ejection fraction â¤ 50% were randomly allocated to receive transcutaneous echo-guided peri-infarct injections of alpha-MEM media (controls), hESC-derived SSEA-1+ cardiac progenitors (500000 cells in 30 Î¼L), or total EV secreted by those 500000 cells in 48 hours in an equivalent volume. The second series also included sham-operated animals for which the needle was inserted into the myocardium in three places without injection. EVs were collected from the cell-secreted medium by ultracentrifugation and characterized by flow cytometry, and nanosight NTS. Outcomes were assessed after 6 weeks by echocardiography, taking LV end-systolic volume (ESV) as the primary end point. Hearts were processed for the assessment of fibrosis and angiogenesis. Total RNA was extracted from carefully selected animals for gene expression analysis by Affymetrix chip. Only animals with similar VTS at baseline were used for this analysis. All data were collected and analyzed blindly. Results: Cardiac progenitors were successfully generated by exposure of the pluripotent ESC to bone morphogenetic protein-2, purified by anti-CD15 immunomagnetic sorting and then cultured on vitronectin for 48 hours, after which cells or EVs derived from the same cell batch were injected. After 6 weeks in the first series, LVESV [mÂ±SEM] in controls did not significantly differ from the pre-injection value (difference: -2.64 Â± 1.54 ÂµL, p=0.12, n= 12). Conversely, in the cell-treated group, LVESV significantly decreased by -4.20 Â± 0.96 ÂµL (p=0.0007, n=16). A similar decrease was seen in the EV-treated group: -5.73 Â± 1.21 ÂµL (p=0.0003, n=15). Similar patterns were seen for LV end-diastolic volumes: controls (-2.46 Â± 1.19 ÂµL, p=NS), cells (-4.48 Â± 1.47 ÂµL, p=0.009), EV (-4.29 Â± 1.31 ÂµL, p=0.005). For the second series, the VTD of cell- and EV-treated animals remained stable (cell: -1.85 Â± 3.27 ÂµL, p=NS, n= 4; EV: +0.05 Â± 1.53 ÂµL, p=NS, n = 4), whereas sham- and control-treated animals deteriorated significantly (sham: +2.20 Â± 0.35 ÂµL, p = 0.003, n = 5; control: +3.27 Â± 0.87 ÂµL, p = 0.03, n = 4). The trend held for VTS, though differences were not significant. Analysis of gene expression data revealed interesting pathways that were more highly expressed in cell- and EV-treated animals than in controls and sham-operated animals. Conclusions: These data support the hypothesis that EVs may be critical mediators of the paracrine effects of cell therapy, and for the sake of streamlining translational processes, deserve to be considered as potential alternatives to stem cell transplantation. Gene expression levels were compared between mouse hearts.

Project description:Microglia are resident immune cells of the brain that play important roles in mediating inflammatory responses in several neurological diseases via direct and indirect mechanisms. One indirect mechanism may involve extracellular vesicle (EV) release, so that the molecular cargo transported by microglia-derived EVs can have functional effects by facilitating intercellular communication. The molecular composition of microglia-derived EVs, and how microglial activation states impacts EV composition and EV-mediated effects in neuroinflammation, remain poorly understood. We hypothesize that microglia-derived EVs have unique molecular profiles that are determined by microglial activation state. Using size-exclusion chromatography to purify EVs from BV2 microglia, combined with proteomic (label-free quantitative mass spectrometry or LFQ-MS) and transcriptomic (mRNA and non-coding RNA seq) methods, we obtained comprehensive molecular profiles of microglia-derived EVs. LFQ-MS identified several classic EV proteins (tetraspanins, ESCRT machinery, and heat shock proteins), in addition to over 200 proteins not previously reported in the literature. Unique mRNA and microRNA signatures of microglia-derived EVs were also identified. After treating BV2 microglia with lipopolysaccharide (LPS), interleukin-10, or transforming growth factor beta, to mimic pro-inflammatory, anti-inflammatory, or homeostatic states, respectively, LFQ-MS and RNA seq revealed novel state-specific proteomic and transcriptomic signatures of microglia-derived EVs. Particularly, LPS treatment had the most profound impact on proteomic and transcriptomic compositions of microglia-derived EVs. Furthermore, we found that EVs derived from LPS-activated microglia were able to induce pro-inflammatory transcriptomic changes in resting responder microglia, confirming the ability of microglia-derived EVs to relay functionally-relevant inflammatory signals. These comprehensive microglia-EV molecular datasets represent important resources for the neuroscience and glial communities, and provide novel insights into the role of microglia-derived EVs in neuroinflammation.

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Proteomic signatures of extracellular vesicles secreted by non-mineralizing and mineralizing human osteoblasts and stimulation of tumor cell growth

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