mRNA present in EPC derived microvescicles were detected using a RNA quantity curve, in order to evaluate if these vescicles were shuttling a specific subset of mRNAs
Endothelial progenitor cell derived microvesicles activate an angiogenic program in endothelial cells by a horizontal transfer of mRNA.
No sample metadata fields
View SamplesSeveral studies indicate that adult stem cells may improve the recovery from acute tissue injury. It has been suggested that they may contribute to tissue regeneration by the release of paracrine factors promoting proliferation of tissue resident cells. However, the factors involved remain unknown. In the present study we found that microvesicles (MV) derived from human liver stem cells (HLSC) were able to stimulate in vitro proliferation and apoptosis resistance of human and rat hepatocytes. These effects required internalization of MV in the hepatocytes by an alpha4 integrin-dependent mechanism. However, when treated with RNase, MV despites their internalization were unable to induce hepatocyte proliferation and apoptosis resistance, suggesting an RNA dependent effect. Microarray analysis and quantitative RT-PCR demonstrated that MV were shuttling a specific subset of cellular mRNA, such as mRNA associated in the control of transcription, translation, proliferation and apoptosis. When administered in vivo, MV were found to accelerate the morphological and functional recovery of liver in a model of 70% hepatectomy in rats by inducing an hepatocytes proliferation that was abolished by RNase treatment. Using human AGO2 gene, which is shuttled by MV, as a reporter gene, we found the expression of human AGO2 mRNA and protein in the liver of hepatectomized rats treated with MV. This suggest a translation of the MV shuttled mRNA within hepatocytes of treated rats. Conclusion: these results suggest that MV derived from HLSC may activate a proliferative program in remnant hepatocytes after hepatectomy by a horizontal transfer of specific mRNA subsets.
Human liver stem cell-derived microvesicles accelerate hepatic regeneration in hepatectomized rats.
Specimen part
View SamplesPhenotypic changes induced by extracellular vesicles (EVs) have been implicated in the recovery of acute kidney injury (AKI) induced by mesenchymal stromal cells (MSCs). miRNAs are potential candidates for cell reprogramming towards a pro-regenerative phenotype. The aim of the present study was to evaluate whether miRNA de-regulation inhibits the regenerative potential of MSCs and derived-EVs in a model of glycerol-induced AKI in SCID mice. For this purpose, we generated MSCs depleted of Drosha, a critical enzyme of miRNA maturation, to alter miRNA expression within MSCs and EVs. Drosha knock-down MSCs (MSC-Dsh) maintained the phenotype and differentiation capacity. They produced EVs that did not differ from those of wild type cells in quantity, surface molecule expression and internalization within renal tubular epithelial cells. However, EVs derived from MSC-Dsh (EV-Dsh) showed global down-regulation of miRNAs. Whereas, wild type MSCs and derived EVs were able to induce morphological and functional recovery in AKI, MSC-Dsh and EV-Dsh were ineffective. RNA sequencing analysis showed that genes deregulated in the kidney of AKI mice were restored by treatment with MSCs and EVs but not by MSC-Dsh and EV-Dsh. Gene Ontology analysis showed that down-regulated genes in AKI were associated with fatty acid metabolism. The up-regulated genes in AKI were involved in inflammation, ECM-receptor interaction and cell adhesion molecules. These alterations were reverted by treatment with wild type MSCs and EVs, but not by the Drosha counterparts. In conclusion, miRNA depletion in MSCs and EVs significantly reduced their intrinsic regenerative potential in AKI, suggesting a critical role of miRNAs. Overall design: RNA-seq
AKI Recovery Induced by Mesenchymal Stromal Cell-Derived Extracellular Vesicles Carrying MicroRNAs.
No sample metadata fields
View SamplesAdministration of exogenous mesenchymal stem cells (MSCs) has been shown to improve the recovery from acute kidney injury (AKI). It has been suggested that the beneficial effect of MSCs is related to the paracrine release of factors favouring proliferation of intrinsic epithelial cells survived to injury rather than to their trans-differentiation. However the factors involved remain to be determined. In the present study we demonstrated that microvesicles (MVs) derived from human bone marrow MSCs are able to stimulate in vitro proliferation and apoptosis resistance of tubular epithelial cells (TEC). In addition, MVs were found to accelerate in vivo the morphological and functional recovery of glycerol induced AKI in SCID mice by inducing TEC proliferation. The effect of MVs on the recovery of AKI was comparable to that of human MSC treatment. In vitro we found that the CD44 and beta1-integrin-dependent incorporation of MVs in TEC was required for their biological action. However, despite their internalization, RNase-treated MVs failed to induce in vitro apoptosis resistance and TEC proliferation, and in vivo recovery from AKI, suggesting an RNA-dependent biological effect. Microarray analysis and quantitative RT-PCR of MV-RNA extract indicated that MVs were shuttling a specific subset of cellular mRNA, such as mRNA associated with the mesenchymal differentiative phenotype and with several cell functions involved in the control of transcription, proliferation, apoptosis and cell immune regulation. These results suggest that MVs derived from MSCs may activate a proliferative program in TEC survived to injury in AKI by an horizontal transfer of mRNA.
Mesenchymal stem cell-derived microvesicles protect against acute tubular injury.
No sample metadata fields
View SamplesThe role of the transcription factor EB (TFEB) in the control of cellular functions, including in vascular bed, is mostly thought to be the regulation of lysosomal biogenesis and autophagic flux. While this is its best-known function, we report here the ability of TFEB to orchestrate a non-canonical program involved in the control of cell-cycle and VEGFR2 pathway in the developing vasculature. In endothelial cells, TFEB deletion halts proliferation by inhibiting the CDK4/Rb pathway, which regulates the cell cycle G1-S transition. In an attempt to overcome this limit, cells compensate by increasing the amount of VEGFR2 on the plasma membrane through a microRNA-mediated mechanism and the control of its membrane trafficking. TFEB transactivates the miR-15a/16-1 cluster, which limits the stability of the VEGFR2 transcript, and negatively modulates the expression of MYO1C, which regulates VEGFR2 delivery to the cell surface. In TFEB knocked-down cells, the reduced and increased amount respectively of miR-15a/16-1 and MYO1C result in the overexpression on plasmamembrane of VEGFR2, which however shows low signaling strength. Using endothelial loss-of-function Tfeb mouse mutants, we present evidence of defects in fetal and newborn mouse vasculature caused by the reduced endothelial proliferation and by the anomalous function of VEGFR2 pathway. Thus, this study revealed a new and unreported function of TFEB that expands its role beyond the regulation of autophagic pathway in the vascular system.
TFEB controls vascular development by regulating the proliferation of endothelial cells.
Cell line
View SamplesTriple-negative (TN) breast cancers need to be refined in order to identify therapeutic subgroups of patients.
Gene-expression molecular subtyping of triple-negative breast cancer tumours: importance of immune response.
Disease
View SamplesA zebrafish forward genetic screen for determinants of susceptibility to Mycobacterium marinum identified a hypersusceptible mutant deficient in the lysosomal hydrolase Cathepsin L that manifests the hallmarks of human lysosomal storage diseases. In uninfected mutants, macrophages progressively accumulate undigested material in their lysosomes, leading to impaired migration and the accumulation of unengulfed cell debris. During mycobacterial infection, these vacuolated macrophages cannot migrate to phagocytose infected macrophages undergoing apoptosis in the tuberculous granuloma. Consequently, unengulfed apoptotic macrophages undergo secondary necrosis causing granuloma breakdown and increased mycobacterial growth. Macrophage lysosomal accumulations similarly impair migration to newly infecting mycobacteria. We find that important aspects of this phenotype are recapitulated in human smokers, who are at increased risk for tuberculosis. A majority of alveolar macrophages from smokers exhibit lysosomal accumulations and do not migrate to Mycobacterium tuberculosis. This incapacitation of highly microbicidal first-responding macrophages may contribute to smokers' susceptibility to tuberculosis. Overall design: A forward genetic screen for zebrafish larvae that are hypersusceptible to Mycobacterium marinum infection identified a mutation in the transcription factor snapc1b at 13: 37996163 (T->C). Individuals of wild type (T/T) and mutant (C/C) were genotyped and pooled respectively for RNA isolation and transcriptome analysis.
Lysosomal Disorders Drive Susceptibility to Tuberculosis by Compromising Macrophage Migration.
No sample metadata fields
View SamplesBackground: Type I interferons (IFNs) are essential to the clearance of viral diseases, in part by initiating upregulation of IFN regulated genes (IRGs). A clear distinction between genes upregulated directly by virus and genes upregulated by secondary IFN production has not been made. Here we investigated the genes regulated by IFN-a2b compared to the genes regulated by SARS-CoV infection in ferrets.
Early gene expression events in ferrets in response to SARS coronavirus infection versus direct interferon-alpha2b stimulation.
Specimen part
View SamplesThe 2009 H1N1 influenza pandemic has prompted a significant need for the development of efficient, single-dose, adjuvanted vaccines. Here we investigated the adjuvant potential of CpG oligodeoxynucleotide (ODN) when used with a human seasonal influenza virus vaccine in ferrets. We found that the CpG ODNadjuvanted vaccine effectively increased antibody production and activated type I interferon (IFN) responses compared to vaccine alone. Based on these findings, pegylated IFN- 2b (PEG-IFN) was also evaluated as an adjuvant in comparison to CpG ODN and complete Freunds adjuvant (CFA). Our results showed that all three vaccines with adjuvant added prevented seasonal human A/Brisbane/59/2007 (H1N1) virus replication more effectively than did vaccine alone. Gene expression profiles indicated that, as well as upregulating IFN-stimulated genes (ISGs), CpG ODN enhanced B-cell activation and increased Toll-like receptor 4 (TLR4) and IFN regulatory factor 4 (IRF4) expression, whereas PEG-IFN augmented adaptive immunity by inducing major histocompatibility complex (MHC) transcription and Ras signaling. In contrast, the use of CFA as an adjuvant induced limited ISG expression but increased the transcription of MHC, cell adhesion molecules, and B-cell activation markers. Taken together, our results better characterize the specific molecular pathways leading to adjuvant activity in different adjuvant-mediated influenza virus vaccinations.
Molecular characterization of in vivo adjuvant activity in ferrets vaccinated against influenza virus.
Specimen part, Treatment
View SamplesROR?t is well recognized as the lineage defining transcription factor for TH17 cell development. However, the cell-intrinsic mechanisms that negatively regulate TH17 cell development and autoimmunity remain poorly understood. Here we demonstrate that the transcriptional repressor REV-ERBa is exclusively expressed in TH17 cells, competes with ROR?t for their shared DNA consensus sequence, and negatively regulates TH17 cell development via repression of genes traditionally characterized as ROR?t-dependent, including Il17a. Deletion of REV-ERBa enhanced TH17-mediated pro-inflammatory cytokine expression, exacerbating experimental autoimmune encephalomyelitis (EAE) and colitis. Treatment with REV-ERB-specific synthetic ligands, which have similar phenotypic properties as ROR? modulators, suppressed TH17 cell development, was effective in colitis intervention studies, and significantly decreased the onset, severity, and relapse rate in several models of EAE without affecting thymic cellularity. Our results establish that REV-ERBa negatively regulates pro-inflammatory TH17 responses in vivo and identifies the REV-ERBs as potential targets for the treatment of TH17-mediated autoimmune diseases. Overall design: 10 samples; 5 conditions with 2 replicates per condition
REV-ERBα Regulates T<sub>H</sub>17 Cell Development and Autoimmunity.
Specimen part, Subject
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