Inactive b1-integrin acts as a cell junction-localized molecular scaffold for Angiopoietin2-TIE2-FOXO1 signaling [RNA-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE316082 | GEO | 2026/03/25
REPOSITORIES: GEO
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Project description:Transcriptome profiling of lymphatic endothelial cells (LECs) treated with multimeric angiopoietin-2 (Ang2) for 3 or 6 hours to investigate early transcriptional responses.
2026-03-25 | GSE315536 | GEO
Project description:Inactive b1-integrin acts as a cell junction-localized molecular scaffold for Angiopoietin2-TIE2-FOXO1 signaling
| PRJNA1398220 | ENA
Project description:Inactive b1-integrin acts as a cell junction-localized molecular scaffold for Angiopoietin2-TIE2-FOXO1 signaling [RNA-Seq]
| PRJNA1400565 | ENA
Project description:Angiopoietin-Tie1 signaling is required for lymphatic vascular integrity and both ANGPT2 and TIE1 genetic variants have been associated with lymphedema in patients1, 2. Concurrent with growth-factor signaling, mechanical forces sensed by lymphatic endothelial cells (LECs) are also needed to regulate lymphatics3, 4. How these two pathways might interact in the lymphatic system is unknown. Here, we identified a regulatory network in LECs linking activation of the mechanosensory channel, PIEZO1 to Angiopoietin-Tie signaling and repression of a downstream FOXO1 transcriptional response. RNAseq analysis of dermal LECs from Tie1-deficient embryos showed persistent FOXO1 activity with downregulation of LEC-associated genes including Ccl21a, Foxc2, Gata2 and Gja4, as well as increased expression of the mechanosensory channel, Piezo1. Activation of PIEZO1 in human dermal LECs (HDLECs) by the small molecule agonist, Yoda1, triggered exocytosis of the Tie ligand, Angiopoietin-2 (ANGPT2), activation of Tie/AKT/PI3K signaling and export of FOXO1 out of the nucleus. Our data identify a novel molecular pathway linking mechano-transduction to ANGPT2-Tie1 activity and dynamic modulation of FOXO1 activity needed for patterning and function of the lymphatic system
2024-03-05 | GSE211849 | GEO
Project description:To analyze the Angiopoietin receptor Tie2 on the arterial endothelial cells during atheroclerosis
2023-01-23 | GSE161979 | GEO
Project description:Angiopoietin-2 (ANG2) regulates blood vessel remodeling in many pathological conditions through differential effects on Tie2 signaling. While ANG2 competes with ANG1 to inhibit Tie2, it can paradoxically also promote Tie2 phosphorylation (p-Tie2). A related paradox is that both inactivation and overactivation of Tie2 can result in vascular remodeling. Here, we reconciled these opposing actions of ANG2 by manipulating conditions that govern its actions in the vasculature. ANG2 drove vascular remodeling during Mycoplasma pulmonis infection by acting as a Tie2 antagonist, which led to p-Tie2 suppression, forkhead box O1 (FOXO1) activation, increased ANG2 expression, and vessel leakiness. These changes were exaggerated by anti-Tie2 antibody, inhibition of PI3K signaling, or ANG2 overexpression and were reduced by anti-ANG2 antibody or exogenous ANG1. In contrast, under pathogen-free conditions, ANG2 drove vascular remodeling by acting as an agonist, promoting high p-Tie2, low FOXO1 activation, and no leakage. Tie1 activation was strong under pathogen-free conditions, but infection or TNF-α led to Tie1 inactivation by ectodomain cleavage and promoted the Tie2 antagonist action of ANG2. Together, these data indicate that ANG2 activation of Tie2 supports stable enlargement of normal nonleaky vessels, but reduction of Tie1 in inflammation leads to ANG2 antagonism of Tie2 and initiates a positive feedback loop wherein FOXO1-driven ANG2 expression promotes vascular remodeling and leakage.
| S-EPMC5004955 | biostudies-literature
Project description:Neuro-vascular communication is essential to synchronize central nervous system development. Yet, the specific cellular players, defined developmental processes and molecular mechanisms involved in this crosstalk remain poorly characterized. Here we identify the angiopoietin/Tie2 signaling axis as a crucial regulator of dendritic morphogenesis of Purkinje cells (PC) during cerebellum development. We show that in the developing cerebellum Tie2 expression is not restricted to blood vessels but it is also in PCs. Its ligands angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) are expressed in neural cells and endothelial cells (ECs), respectively. PC-specific deletion of Tie2 results in reduced dendritic arborization, which is recapitulated in neural-specific Ang1-knockout and Ang2 full-knockout mice. Mechanistically, RNA sequencing reveals that Tie2 deficient PCs present alterations in gene expression of multiple genes involved in cytoskeleton organization, dendritic formation, growth and branching. Functionally, those morphological changes are accompanied by alterations in PC network electrophysiology. Altogether, our data propose that the Ang/Tie2 signaling axis serve as mediator of intercellular communication between neural cells, ECs and PCs, required to regulate PC dendritic morphogenesis and function.
2021-12-31 | GSE178659 | GEO
Project description:Vascular endothelial protein tyrosine phosphatase (VE-PTP, PTPRB) is a receptor type phosphatase that is crucial for the regulation of endothelial junctions and blood vessel development. VE-PTP regulates vascular integrity by dephosphorylating substrates which are key players in endothelial junction stability, such as the angiopoietin receptor TIE2, the endothelial adherens junction protein VE-cadherin and the vascular endothelial growth factor receptor VEGFR2. Here, we have systematically searched for novel substrates of VE-PTP in endothelial cells by utilizing two approaches. First, we studied changes in the endothelial phosphoproteome upon exposing cells to a highly VE-PTP-specific phosphatase inhibitor followed by affinity isolation and mass-spectrometric analysis of phosphorylated proteins by phosphotyrosine-specific antibodies. Second, we used a substrate trapping mutant of VE-PTP to pull down phosphorylated substrates in combination with SILAC-based quantitative mass spectrometry measurements. We identified a set of substrate candidates of VE-PTP, of which a remarkably large fraction is related to cell junctions (48/165; 29.1%). Several of those were found in both screens and displayed very high connectivity in predicted functional interaction networks. The receptor protein tyrosine kinase EPHB4 was the most prominently phosphorylated protein upon VE-PTP inhibition among those VE-PTP targets that were identified by both proteomic approaches. Further analysis revealed that EPHB4 forms a ternary complex with VE-PTP and TIE2 in endothelial cells. VE-PTP controls the phosphorylation of each of these two tyrosine kinase receptors. Despite of their simultaneous presence in a ternary complex, stimulating each of the receptors with their own specific ligand did not cross-activate the respective partner receptor. Our systematic approach has led to the identification of novel substrates of VE-PTP, of which many are relevant for the control of cellular junctions further promoting the importance of VE-PTP as a key player of junctional signalling.
2019-08-20 | PXD011940 | Pride
Project description:Angiopoietin-2 (ANG-2) is a key regulator of angiogenesis that exerts context-dependent effects on ECs. ANG-2 binds the endothelial-specific receptor tyrosine kinase 2 (TIE2) and acts as a negative regulator of ANG-1/TIE2 signaling during angiogenesis, thereby controlling the responsiveness of ECs to exogenous cytokines. Recent data from tumors indicate that under certain conditions ANG-2 can also promote angiogenesis. However, the molecular mechanisms of dual ANG-2 functions are poorly understood. Here, we identify a model for the opposing roles of ANG-2 in angiogenesis. We found that angiogenesis-activated endothelium harbored a subpopulation of TIE2-negative ECs (TIE2lo). TIE2 expression was downregulated in angiogenic ECs, which abundantly expressed several integrins. ANG-2 bound to these integrins in TIE2lo ECs, subsequently inducing, in a TIE2-independent manner, phosphorylation of the integrin adaptor protein FAK, resulting in RAC1 activation, migration, and sprouting angiogenesis. Correspondingly, in vivo ANG-2 blockade interfered with integrin signaling and inhibited FAK phosphorylation and sprouting angiogenesis of TIE2lo ECs. These data establish a contextual model whereby differential TIE2 and integrin expression, binding, and activation control the role of ANG-2 in angiogenesis. The results of this study have immediate translational implications for the therapeutic exploitation of angiopoietin signaling.
| S-EPMC3366398 | biostudies-literature
Project description:BackgroundVenous malformations (VMs), most of which associated with activating mutations in the endothelial cells (ECs) tyrosine kinase receptor TIE2, are characterized by dilated and immature veins with scarce smooth muscle cells (SMCs) coverage. However, the underlying mechanism of interaction between ECs and SMCs responsible for VMs has not been fully understood.MethodsHere, we screened 5 patients with TIE2-L914F mutation who were diagnosed with VMs by SNP sequencing, and we compared the expression of platelet-derived growth factor beta (PDGFB) and α-SMA in TIE2 mutant veins and normal veins by immunohistochemistry. In vitro, we generated TIE2-L914F-expressing human umbilical vein endothelial cells (HUVECs) and performed BrdU, CCK-8, transwell and tube formation experiments on none-transfected and transfected ECs. Then we investigated the effects of rapamycin (RAPA) on cellular characteristics. Next we established a co-culture system and investigated the role of AKT/FOXO1/PDGFB in regulating cross-talking of mutant ECs and SMCs.ResultsVMs with TIE2-L914F mutation showed lower expression of PDGFB and α-SMA than normal veins. TIE2 mutant ECs revealed enhanced cell viability and motility, and decreased tube formation, whereas these phenotypes could be reversed by rapamycin. Mechanically, RAPA ameliorated the physiological function of mutant ECs by inhibiting AKT-mTOR pathway, but also facilitated the nuclear location of FOXO1 and the expression of PDGFB in mutant ECs, and then improved paracrine interactions between ECs and SMCs. Moreover, TIE2 mutant ECs strongly accelerated the transition of SMCs from contractile phenotype to synthetic phenotype, whereas RAPA could prevent the phenotype transition of SMCs.ConclusionsOur data demonstrate a previously unknown mechanistic linkage of AKT-mTOR/FOXO1 pathway between mutant ECs and SMCs in modulating venous dysmorphogenesis, and AKT/FOXO1 axis might be a potential therapeutic target for the recovery of TIE2-mutation causing VMs. Video Abstract.
| S-EPMC7457504 | biostudies-literature