Notch signaling is one of the central regulators of differentiation in a variety of organisms and tissue types. Within the hematopoietic system, Notch is essential for the emergence of definitive HSC during fetal life and controls adult HSC differentiation to the T-cell lineage. Notch activation is controlled by the gamma-secretase complex complex, composed of presenilin, nicastrin (Ncstn), anterior pharynx-1 (Aph1), and presenilin enhancer-2
A novel tumour-suppressor function for the Notch pathway in myeloid leukaemia.
Sex, Age
View SamplesNotch signaling is one of the central regulators of differentiation in a variety of organisms and tissue types. Within the hematopoietic system, Notch is essential for the emergence of definitive HSC during fetal life and controls adult HSC differentiation to the T-cell lineage. Notch activation is controlled by the gamma-secretase complex complex, composed of presenilin, nicastrin (Ncstn), anterior pharynx-1 (Aph1), and presenilin enhancer-2
A novel tumour-suppressor function for the Notch pathway in myeloid leukaemia.
Sex, Age
View SamplesNotch signaling is one of the central regulators of differentiation in a variety of organisms and tissue types. Within the hematopoietic system, Notch is essential for the emergence of definitive HSC during fetal life and controls adult HSC differentiation to the T-cell lineage. Notch activation is controlled by the gamma-secretase complex complex, composed of presenilin, nicastrin (Ncstn), anterior pharynx-1 (Aph1), and presenilin enhancer-2
A novel tumour-suppressor function for the Notch pathway in myeloid leukaemia.
Sex, Age
View SamplesMouse aorta smooth muscle cells (SMCs) express TNF receptor superfamily member 1A (TNFR1) and lymphotoxin receptor (LTR). Circumstantial evidence has linked the SMC LTR to tertiary lymphoid organogenesis in diseased aortae of hyperlipidemic mice. Here, we explored potential roles of TNFR1 and LTR activation in cultured SMCs. TNFR1 signaling by TNF activated the classical RelA NF-B pathway, whereas LTR signaling by agonistic anti LTR antibody activated both the classical RelA and alternative RelB NF-B pathways. Addition of both agonists synergized to enhance p100 inhibitor processing to the p52 subunit of NF-B and promoted its nuclear translocation suggesting RelA-RelB cross-talk in transcription regulation. Correspondingly, microarrays showed that simultaneous TNFR1 and LTR activation when compared to activation of single receptors was followed by markedly elevated levels of mRNAs encoding leukocyte homeostatic chemokines CCL2, CCL5, CXCL1, and CX3CL1. Furthermore, SMCs acquired prototypical features of mesenchymal cells known as lymphoid tissue organizers (LTOs), which control tertiary lymphoid organogenesis in autoimmune diseases, through hyperinduction of CCL7, CCL9, CXCL13, CCL19, CXCL16, VCAM-1, and ICAM-1. Experiments with ltbr-/- SMCs suggested that the LTR-RelB activation component of NF-B signaling was obligatory to generate the LTO phenotype. TNFR1-LTR crosstalk also resulted in augmented synthesis and prolonged secretion of lymphorganogenic chemokine proteins into the culture medium. Thus, combined TNFR1-LTR signaling triggers SMC transdifferentiation into a phenotype that strikingly resembles LTOs. LTO-like SMCs may adopt a thus far unrecognized role in diseased arteries, i.e. to coordinate tertiary lymphoid organogenesis in atherosclerosis, aortic aneurysm, and transplant vasculopathy.
Mouse aorta smooth muscle cells differentiate into lymphoid tissue organizer-like cells on combined tumor necrosis factor receptor-1/lymphotoxin beta-receptor NF-kappaB signaling.
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View SamplesCultured mouse aorta endothelial cells (from 8-12 weeks old C57BL/6J mice, passage 2-3) were exposed to phosphate buffered saline (control) or a combination of TNFalpha plus agonistic alpha-LTR antibody for 24 hours as described in Ltzer et al. 2009. Arterioscler. Thromb. Vasc. Biol., in press. Total RNA was extracted and microarrays were prepared.
Mouse aorta smooth muscle cells differentiate into lymphoid tissue organizer-like cells on combined tumor necrosis factor receptor-1/lymphotoxin beta-receptor NF-kappaB signaling.
Specimen part
View SamplesWe previously observed that formation of aorta and innominate artery atherosclerotic lesions in the intima of hyperlipidemic apoE-deficient mice but not wild-type mice was accompanied by a marked age-dependent adventitial T cell infiltration. As the mice aged, adventitial T cells formed T/T cell-, T/B cell-, and T/B/dendritic cell aggregates adjacent to atherosclerotic lesions. Some of the adventitial infiltrates formed large clusters of various immune cells including T cells, B cells (centrocytes, follicular mantle cells), dendritic cells, follicular dendritic cells, and plasma cells with preferential formation in the suprarenal portion of the abdominal aorta. These data demonstrated that the immune lineage cell composition of atherosclerotic lesions and adventitia were distinct: The macrophage-foam cell-, T cell-, and SMC-dominated cell composition of atherosclerosis lesions versus the presence of immune cells capable of carrying out antigen-dependent T cell-driven humoral immune responses in the adventitia also indicated that immune reactions carried out in lesions or the adventitia are fundamentaly different. To distinguish between immunity-regulating genes in atherosclerosis lesions versus the adventitia, a combination of microarray profiling and laser capture microdissection was used. Stringent filters revealed 1163 differentially up-regulated probesets in apoE-/- mouse aortae at 78 weeks (w) versus 6 w. A fuzzy c-means cluster algorythm identified 2 clusters that significantly differed in their slope angles between time points: An apparent atherosclerosis cluster consisted of 771 probesets and an apparent adventitia cluster consisted of 392 probesets. Up-regulated genes at 32 w mirrored the influx of monocyte/macrophages into intima lesions whereas genes up-regulated between 32-78 w mirrored adventitial inflammation. To segregate both clusters into separate gene ontology (GO) molecular function groups, we determined statistically significant up-regulation (unpaired Student t-test; p < 0.05) between 6-32 w for the atherosclerosis cluster and between 32-78 w for the adventitia cluster. Among others, GO molecular function terms cytokine activity, cytokine binding, and immunoglobulin binding in the atherosclerosis cluster and cytokine activity, chemokine receptor activity, and antigen binding in the ATLO cluster suggested candidate genes in relation to inflammation triggered by macrophages or adventitia infiltration, respectively. Among other prototype atherosclerosis genes such as Itgax (complement receptor 4), Cd68, Lysz (lysozyme), Vcam1, and Icam1, the atherosclerosis cluster showed markedly overrepresented prototype macrophage/foam cell genes regulating inflammation in cytokine activity (GO: 0005125): Spp1 (osteopontin) and Il6; in cytokine binding (GO: 0019955) Cd74, Il10rb, Ccr2, and Ccr5; and in immunoglobulin binding (GO: 00119865) the proinflammatory galactose-binding lectin Lgals3, as well as genes in scavenger receptor activity and lipid transporter activity. By contrast, the adventitia cluster showed overrepresented genes regulating B cell recruitment, B cell maturation, germinal center formation, and autoimmunity in cytokine activity including Cxcl13, Ccl21, and Ltb, in CXC chemokine receptor activity the secondary lymphoid organ counterreceptor of CXCL13 Blr1 (also known as Cxcr5), Cxcr3, and Cxcr6; and in antigen binding several histocompatibility-2 loci and various markedly expressed immunoglobulin genes. As embryonic lymph node development and tertiary lymphoid organ neogenesis share common features signal intensities of genes specifying the GO molecular function term lymph node development (GO: 0048535) were examined in arrays prepared from wild-type and apoE-/- aortae. These results showed that Id2, Nfkb1, and Ltbr were constitutively expressed at significant levels in aortae of both mouse genotypes whereas other genes including Lta, Ltb, Glycam1, and the two lymphorganogenic genes Cxcl13 and Ccl21 were induced at 78 w in apoE-deficient aortae only. Thus, genes expressed by macrophage-foam cells and genes regulating ATLO neogenesis, embryonic lymph node development, or B cell maturation were constitutively expressed in the arterial wall in both genotypes or emerged in a stepwise fashion at 32 w and 78 w. To verify microarray signal intensity data, separate aortae extracts were examined by quantitative RT-PCR (QRT-PCR) analyses of wild-type and apoE-deficient mice at 32 and 78 w. These data showed that array signal values accurately reflected gene transcripts. Cell lineage analyses of the adventitial infiltrate and kinetic aorta microarray- and QRT-PCR analyses thus provided circumstantial evidence that immune responses in atherosclerosis intima lesions and the adventitia were distinct. To examine this possibility further, we selected areas of the abdominal aorta burdened with advanced lesions and separated lesions and corresponding adventitial infiltrates of 78 w old apoE-deficient mice by laser dissection microscopy. In addition, adventitiae of aorta segments that were not associated with adjacent lesions and adventitiae of wild-type mice were prepared. Consistent with the lack of a major adventitial leukocyte infiltration, wild-type adventitiae showed gene expression levels that were similar to lesion-free adventitiae of apoE-deficient mice indicating that atherosclerotic lesions directly affected adventitial inflammation in a segmental fashion. Stringent filter criteria identified genes that were differentially expressed in adventitiae and atherosclerotic lesions. Statistical analyses of overrepresented genes in GO molecular function or biological process groups were particularly instructive in cytokine activity, cytokine binding, antigen processing and presentation as well as in lymph node development. Thus, adventitiae in aorta segments with associated atherosclerotic lesions in cytokine activity showed overrepresentation of genes known to be associated with tertiary lymphoid organ formation including Cxcl13, Ccl21, and Ltb, whereas atherosclerotic lesions showed overrepresentation of prototype atherosclerosis-associated genes Ssp1 (osteopontin), Bmp4 (bone morphogenic protein 4), and Cxc3cl1 (fractalkine); in cytokine binding adventitiae showed overrepresentation of receptors implicated in B cell immunity and autoimmunity including Brl1 (counterreceptor for CXCL13), Ccr7, Tnfrsf4, and Cxcr3 whereas lesions showed overrepresentation of inflammatory mediator receptors including Tnfrs1b, Tgfbr1, and Il7r; moreover, in antigen processing and presentation, adventitiae showed overrepresentation of several histocompatibility loci; additional adventitial gene expression overrepresentations were observed in lymph node development (Fas, SpiB, Ltb, Flt3) whereas lesions showed expression of prototype macrophage genes including Tlr4, Tgfb1, and Tgfb2. These data provide comprehensive topographical transcriptome information in adventitial tissue adjacent to atherosclerotic lesions versus lesions and are expected to form the basis for future cell lineage expression analyses using single cell detection methodology including ISH.
Lymphotoxin beta receptor signaling promotes tertiary lymphoid organogenesis in the aorta adventitia of aged ApoE-/- mice.
Sex, Age, Specimen part
View SamplesThe human cytomegalovirus (HCMV) encodes the chemokine receptor US28 that exhibits constitutive activity. NIH-3T3 cells stably transfected with US28 present a pro-angiogenic and transformed phenotype both in vitro and in vivo.
The human cytomegalovirus-encoded chemokine receptor US28 promotes angiogenesis and tumor formation via cyclooxygenase-2.
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View SamplesVascular smooth muscle cells (VSMC) are important for contraction, blood flow distribution and regulation of blood vessel diameter, but to what extent they contribute to the integrity of blood vessels and blood-brain barrier function is less well understood. In this report, we explored the impact of the progressive loss of VSMC in the Notch3-/- mouse on blood vessel integrity in the central nervous system
Notch3 is necessary for blood vessel integrity in the central nervous system.
Age, Specimen part
View SamplesThe blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB.
Pericytes regulate the blood-brain barrier.
Sex, Age, Specimen part
View SamplesThe mechanisms involved in epithelium-stroma interactions remain poorly understood, despite the importance of the microenvironment during tumorigenesis. Here, we studied the role of Ets2 transcrpiton factor in tumor associated fibroblasts in the MMTV-ErbB2 mammary tumor model. Inactivation of Ets2 specifically in fibroblasts using Fsp-cre significantly reduced tumor growth, in contrast to Ets2 inactivation in epithelium in which no differences in tumor growth were observed.
Ets2 in tumor fibroblasts promotes angiogenesis in breast cancer.
Age, Specimen part
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