High uniform fluid shear stress (FSS) is atheroprotective and preserves the endothelial phenotype and function through activation of downstream mediators such as MAPK7 (Erk5). Endothelial cells respond to FSS thanks to mechanotransduction. However, how the resulting signaling is integrated and resolved at the epigenetic level, remains elusive. We hypothesized that Polycomb methyltransferase EZH2 is involved in the effects of FSS in human endothelial cells. We showed that FSS decreases the expression of the Polycomb methyltransferase EZH2. Despite simultaneous activation of MAPK7, MAPK7 pathway does not directly influence the transcription of EZH2. Interestingly though, the knock down of EZH2 activates the protective MAPK7 signaling in endothelial cells, even in the absence of FSS. To understand the influence of the FSS-decreased expression of EZH2 on endothelial transcriptome, we performed RNA-seq and differential gene expression analysis. We identified candidate groups of genes dependent on both EZH2 and FSS. Among those, Gene Ontology overrepresentation analysis revealed highly significant enrichment of the cell cycle-related genes, suggesting changes in proliferation. Indeed, the depletion of EZH2 strongly inhibited endothelial proliferation, indicating cell cycle arrest. The concomitant decrease in CCNA expression suggests the transition of endothelial cells into a quiescent phenotype. Further bioinformatical analysis suggested TXNIP as a possible mediator between EZH2 and cell cycle-related gene network. Our data show that EZH2 is a FSS-responsive gene. Decreased EZH2 levels enhance the activation of the atheroprotective MAPK7 signaling. Decrease in EZH2 under FSS mediates the decrease in the expression of the network of cell cycle-related genes, which allows the cells to enter quiescence. EZH2 is therefore important for the protective effects of FSS in endothelium. Overall design: Puromycin-selected HUVEC (Human Umbilical Vein Endothelial Cells, Lonza, Switzerland) cells, expressing either scrambled control (SCR) or anti-EZH2 short-hairpin (shEZH2) constructs (at total 7 days after the first viral transduction), were used in FSS experiments (72h of control static culture or exposure to 20 dynes/cm2 of fluid shear stress, using Ibidi pump system (in µ-Slides I 0.4 Luer, Ibidi, Planegg/Martinsried, Germany)). Each replicate experiment consisted of viral transductions and puromycin selection of a separate HUVEC batch, followed by the FSS experiment. Two FSS experimental sets of the same HUVEC batch were run every time in parallel and lysed at the same end time point, one in RNAse-free conditions with RNA-Easy Mini Plus kit RLT Plus lysis buffer (QIAGEN, Venlo, The Netherlands), and one with RIPA buffer. The RIPA-lysates were analyzed with Western blotting and confirmed the complete (no protein present) knock-down of EZH2. From the RNA-lysates, RNA was isolated using the RNA-Easy Mini Plus kit (QIAGEN, Venlo, The Netherlands). High quality RNA samples (pre-assessed by Nanodrop measurements) were further processed in the Genome Analysis Facility of the University Medical Center Groningen. The RNA quality and integrity were verified using PerkinElmer Labchip GX with a cut-off value of 9 (scale 1 to 10, where 9 is very high quality RNA). RNA library was created in accordance with the TruSeqTM RNA Sample Preparation v2 Guide (Illumina, San Diego, CA, USA), using the PerkinElmer Sciclone liquid handler, resulting in 330bp cDNA fragments. The paired-end sequencing (100bp reads) was performed using the Illumina HiSeqTM 2500. (Quoted from the Materials and Methods of the related manuscript, with adjustments).
The decrease in histone methyltransferase EZH2 in response to fluid shear stress alters endothelial gene expression and promotes quiescence.
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Differentiation of human and murine induced pluripotent stem cells to microglia-like cells.
Specimen part
View SamplesMicroglia are the resident inflammatory cells of the central nervous system (CNS) and have important roles in development, homeostasis and a variety of neurologic and psychiatric diseases. Difficulties in procuring human microglia have limited their study and hampered the clinical translation of microglia-based treatments shown to be effective in animal disease models. Here, we report the differentiation of human induced pluripotent stem cells (iPSC) into microglia-like cells by exposure to defined factors and co-culture with astrocytes. These iPSC-derived microglia (iPS-MG) have the phenotype, gene expression profile and functional properties of brain-isolated microglia. Murine iPS-MG generated using a similar protocol have equivalent efficacy to primary brain-isolated microglia in the treatment of murine syngeneic intracranial malignant gliomas. The ability to generate human microglia facilitates the further study of this important CNS cell type and raises the possibility of their use in personalized medicine applications.
Differentiation of human and murine induced pluripotent stem cells to microglia-like cells.
Specimen part
View SamplesLoss of KChIP2 during cardiac stress has been suggested to have a transcriptional impact on cardiac ion channels contributing to maladaptive electrical remodeling. Therefore, we tested the consequence of KChIP2 loss, in the absence of cardiac stress, by treating cultured neonatal rat ventricular myocytes with shRNA for KChIP2 and subsequently performed whole-transcriptome microarray analysis to identify gene changes.
KChIP2 is a core transcriptional regulator of cardiac excitability.
Specimen part
View SamplesMuch is known concerning the cellular and molecular basis for CD8+ T memory immune responses. Nevertheless, conditions that selectively support memory generation have remained elusive. Here we show that an immunization regimen that delivers TCR signals through a defined antigenic peptide, inflammatory signals through LPS, and growth and differentiation signals through the IL-2R initially favors antigen-specific CD8+ T cells to rapidly and substantially develop into tissue-residing T effector-memory cells by TCR transgenic OVA-specific OT-I CD8+ T cells. Amplified CD8+ T memory development depends upon a critical frequency of antigen-specific T cells and direct responsiveness to IL-2. A homologous prime-boost immunization protocol with transiently enhanced IL-2R signaling in normal mice led to persistent polyclonal antigen-specific CD8+ T cells that supported protective immunity to Listeria monocytogenes. These results identify a general approach for amplified T memory development that may be useful to optimize vaccines aimed at generating robust cell-mediated immunity.
Transient enhanced IL-2R signaling early during priming rapidly amplifies development of functional CD8+ T effector-memory cells.
Sex, Specimen part
View SamplesT-cell/histiocyte rich B cell lymphoma (THRBL) and nodular lymphocyte predominant Hodgkin's lymphoma (NLPHL) share some morphological characteristics, including a prominent stromal reaction, but display a markedly different prognosis. To investigate the difference between the stromal reactions of these lymphomas at the molecular level, we performed microarray expression profiling on a series of THRBL and NLPHL cases.
T-cell/histiocyte-rich large B-cell lymphoma shows transcriptional features suggestive of a tolerogenic host immune response.
Sex, Specimen part
View SamplesThis study determined the genes that are differentially expressed when regulatory T cells (Tregs) were isolated from the lamina propria of the small and large intestine from mice with impaired IL-2R signaling (designated Y3) or impaired IL-2R signaling and lack of CD103 expression (designated Y3/CD103-/-) when compared to Tregs from WT mice. 204 unique annotated mRNAs were differentially expressed by 1.5 fold between these 3 groups (Fig. 6B). Very few mRNAs were uniquely up or down regulated in relationship to impaired IL-2R signaling or the combination of impaired IL-2R signaling and lack of CD103 expression. Thus, lack of CD103 does not obviously regulated signaling in Tregs in the gut mucosa and most differentially expressed genes were due to impaired IL_2R signaling. Gene enrichment analysis of these differentially expressed genes identified 4 major enrichment groups (EG) are: EG1, Cytokine-cytokine receptor interaction and the JAK-STAT signaling pathway; EG2, regulation of lymphocyte activation and proliferation; EG3, regulation of cell death and the caspase pathway in apoptosis; and EG4, transcription.
IL-2Rβ-dependent signaling and CD103 functionally cooperate to maintain tolerance in the gut mucosa.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A molecular portrait of gastrointestinal stromal tumors: an integrative analysis of gene expression profiling and high-resolution genomic copy number.
Sex, Age, Specimen part
View SamplesIn addition to KIT and PDGFRA mutations, sequential accumulation of other genetic events is involved in the development and progression of gastrointestinal stromal tumors (GISTs). Until recently, the significance of these other alterations has not been thoroughly investigated. The combination of gene expression profiling and high-resolution genomic copy number analysis offers a detailed molecular portrait of GISTs, providing an essential comprehensive knowledge necessary to guide the discovery of novel target genes involved in tumor development and progression.
A molecular portrait of gastrointestinal stromal tumors: an integrative analysis of gene expression profiling and high-resolution genomic copy number.
Sex, Age, Specimen part
View SamplesThe lack of mouse models permitting the specific ablation of tissue-resident macrophages and monocyte-derived cells complicates understanding of their contribution to tissue integrity and to immune responses. Here we use a new model permitting diphtheria-toxin (DT)-mediated depletion of those cells and in which dendritic cells are spared. We showed that the myeloid cells of the mouse ear skin dermis are dominated by a population of melanin-laden macrophages, called melanophages, that has been missed in most previous studies. By using gene expression profiling, DT-mediated ablation and parabiosis, we determined their identity including their similarity to other skin macrophages, their origin and their dynamics. Limited information exist on the identity of the skin cells responsible for long-term tattoo persistence. Benefiting of our knowledge on melanophages, we showed that they are responsible for retaining tattoo pigment particles through a dynamic process which characterization has direct implications for improving strategies aiming at removing tattoos.
Unveiling skin macrophage dynamics explains both tattoo persistence and strenuous removal.
Specimen part, Treatment
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