Project description:To further investigate the mechanism how the decline in Notch signaling induces premature senescence in endothelial cells, we performed microarray analysis and identified Id1 nd DUSP1 as the downstream molecules of Notch pathway. In quantitative PCR and western blot analyses, the expression level of Id1 and DUSP1 increased in Notch1 over-expressing endothelial cells and decreased in knockdown similar to the result of microarray.
Project description:To further investigate the mechanism how the decline in Notch signaling induces premature senescence in endothelial cells, we performed microarray analysis and identified Id1 nd DUSP1 as the downstream molecules of Notch pathway. In quantitative PCR and western blot analyses, the expression level of Id1 and DUSP1 increased in Notch1 over-expressing endothelial cells and decreased in knockdown similar to the result of microarray. The gene expression of human unbilical endothelial vein cells (HUVEC) infected with retroviral vectors encoding Jagged1, Jagged1-shRNA, or Notch1-shRNA. HUVEC infected with empty vector was used as a control. In each genotypes, three independent lines at passage 8 were performed.
Project description:Dysfunction of vascular endothelium is characteristic of many aging-related diseases, including Alzheimers disease (AD) and AD-related dementias (ADRD). While it is widely posited that endothelial cell dysfunction contributes to the pathogenesis and/or progression of AD/ADRD, it is not clear how. A plausible hypothesis is that intercellular trafficking of extracellular vesicles (EVs) from senescent vascular endothelial cells promotes vascular endothelial cell dysfunction. To test this hypothesis, we compared the expression of proteins and miRNAs in EVs isolated from early passage (EP) vs. senescent (SEN) primary human coronary artery endothelial cells (HCAECs) from the same donor. Proteomics and miRNA libraries constructed from these EV isolates were evaluated using FunRich gene ontology analysis to compare functional enrichment between EP and SEN endothelial cell EVs (ECEVs). Replicative senescence was associated with altered EV abundance and contents independent of changes in EV size. Unique sets of miRNAs and proteins were differentially expressed in SEN-ECEVs, including molecules related to cell adhesion, barrier integrity, receptor signaling, endothelial-mesenchymal transition and cell senescence. miR-181a-5p was the most upregulated miRNA in SEN-ECEVs, increasing >5-fold. SEN-ECEV proteomes supported involvement in several pro-inflammatory pathways consistent with senescence and the senescence-associated secretory phenotype (SASP). These data indicate that SEN-ECEVs are enriched in bioactive molecules implicated in senescence-associated vascular dysfunction, blood-brain barrier impairment, and AD/ADRD pathology. These observations suggest involvement of SEN-ECEVs in the pathogenesis of vascular dysfunction associated with AD/ADRD.
Project description:The Notch pathway is a major regulator of endothelial transcriptional specification. Targeting the Notch receptors or the ligand Dll4 dysregulates angiogenesis. Here, by analyzing single and compound genetic mutants for all Notch signaling members, we find significant differences in the way ligands and receptors regulate liver vascular homeostasis. Loss of Notch receptors caused endothelial hypermitogenic cell-cycle arrest and senescence. Conversely, Dll4 loss triggered a strong Myc-driven transcriptional switch, inducing endothelial proliferation and the tip-cell state. Myc loss suppressed the induction of angiogenesis in the absence of Dll4, without preventing the vascular enlargement and organ pathology. Similarly, inhibition of other pro-angiogenic pathways, including MAPK/ERK and mTor, had no effect on the vascular expansion induced by Dll4 loss; however, anti-VEGFA treatment prevented it without fully suppressing the transcriptional and metabolic programs. This study shows incongruence between single-cell transcriptional states, vascular phenotypes, and related pathophysiology. Our findings also suggest that vascular structure abnormalization, rather than neoplasms, causes the reported anti-Dll4 antibody toxicity.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:The Notch pathway is a major regulator of endothelial transcriptional specification. Targeting the Notch receptors or the ligand Dll4 induces angiogenesis. Here, by analyzing single and compound genetic mutants for all Notch signaling members, we find significant differences in the way ligands and receptors regulate liver vascular homeostasis. Loss of Notch receptors caused endothelial hypermitogenic cell-cycle arrest and senescence. Conversely, Dll4 loss triggered a strong Myc-driven transcriptional switch inducing endothelial proliferation and the tip-cell state. Myc loss suppressed the induction of angiogenesis in the absence of Dll4, without preventing the vascular enlargement and organ pathology. Similarly, inhibition of other pro-angiogenic pathways, including MAPK/ERK and mTor, had no effect on the vascular expansion induced by Dll4 loss, however, anti-VEGFA treatment prevented it without fully suppressing the transcriptional and metabolic programs. This study shows incongruence between single-cell transcriptional states, vascular phenotypes, and related pathophysiology. Our findings also suggest that the vascular structure abnormalization, rather than neoplasms, causes the reported anti-Dll4 antibody toxicity.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.
Project description:Laminar shear stress regulates blood vessel morphogenesis and subsequent quiescence, but how endothelial cells (EC) enact and maintain the vascular homeostasis required in most vessels for proper vessel function is poorly understood. SMAD6, a scaffold for several signaling pathways, is expressed in developing arteries and its expression is flow-regulated. We found that SMAD6 is essential for endothelial cell flow-mediated responses, and that it functions downstream of the mechanosensor Notch1. Endothelial cells with reduced SMAD6 levels failed to align under stable laminar shear flow that promotes vascular homeostasis, while forced SMAD6 expression rescued misalignment induced by reduced Notch1 signaling. SMAD6-dependent homeostatic laminar flow required the Notch ligand Dll4 and Notch transcriptional activity. Mechanistically, neither the N-terminal nor the C-terminal domain of SMAD6 alone rescued flow alignment upon loss of Notch signaling. Endothelial cells with reduced Smad6 levels has compromised barrier function, and RNA profiling revealed upregulation of proliferation-associated genes and down regulation of junction-associated genes. Among junction-related genes affected by SMAD6 levels, the proto-cadherin PCDH12 was upregulated by homeostatic flow and required for proper flow-mediated endothelial cell alignment. Thus, SMAD6 is a critical integrator of flow-mediated signaling inputs downstream of Notch1, as vessels transition from an angiogenic to a homeostatic phenotype.
Project description:We assessed the transcriptional profiles of sorted lung endothelial cells from WT, DNMAML, and Notch1f/f mouse models. The goal of the study is to determine the signaling pathways downstream of Notch signaling that are involved in the regulation of pulmonary vascular permeability
Project description:Angiogenic homeostasis is maintained by a balance between vascular endothelial growth factor (VEGF) and Notch signalling in endothelial cells (ECs). We screened for molecules that might mediate the coupling of VEGF signal transduction with down-regulation of Notch signalling, and identified B-cell chronic lymphocytic leukemia/lymphoma6-associated zinc finger protein (BAZF). BAZF was induced by VEGF-A in ECs to bind to the Notch signalling factor CBF1, and to promote the degradation of CBF1 through polyubiquitination in a CBF1-cullin3 (CUL3) E3 ligase complex. BAZF disruption in vivo decreased endothelial tip cell number and filopodia protrusion, and markedly abrogated vascular plexus formation in the mouse retina, overlapping the retinal phenotype seen in response to Notch activation. Further, impaired angiogenesis and capillary remodeling were observed in skin-wounded BAZF-/- mice. We therefore propose that BAZF supports angiogenic sprouting via BAZF-CUL3-based polyubiquitination-dependent degradation of CBF1 to down-regulate Notch signalling. Human umbilical vein endothelial cells were stimulated with recombinant human VEGF165 for 0, 1, 2, 6, 12, 24 and 48 hours.