scholarly journals Effects of a synthetic PEG-ylated Tie-2 agonist peptide on endotoxemic lung injury and mortality

2011 ◽  
Vol 300 (6) ◽  
pp. L851-L862 ◽  
Author(s):  
Sascha David ◽  
Chandra C. Ghosh ◽  
Philipp Kümpers ◽  
Nelli Shushakova ◽  
Paul Van Slyke ◽  
...  
Keyword(s):  
Mouse Model ◽  
Lethal Dose ◽  
Phage Display Library ◽  
Vascular Leakage ◽  
Vascular Endothelial ◽  
Protective Effects ◽  
Gap Formation ◽  
Diabetic Ulcer ◽  
Vascular Endothelial Cadherin

A synthetic 7-mer, HHHRHSF, was recently identified by screening a phage display library for binding to the Tie-2 receptor. A polyethylene-oxide clustered version of this peptide, termed vasculotide (VT), was reported to activate Tie-2 and promote angiogenesis in a mouse model of diabetic ulcer. We hypothesized that VT administration would defend endothelial barrier function against sepsis-associated mediators of permeability, prevent lung vascular leakage arising in endotoxemia, and improve mortality in endotoxemic mice. In confluent human microvascular endothelial cells, VT prevented endotoxin-induced (lipopolysaccharides, LPS O111:B4) gap formation, loss of monolayer resistance, and translocation of labeled albumin. In 8-wk-old male C57Bl6/J mice given a ∼70% lethal dose of endotoxin (15 mg/kg ip), VT prevented lung vascular leakage and reversed the attenuation of lung vascular endothelial cadherin induced by endotoxemia. These protective effects of VT were associated with activation of Tie-2 and its downstream mediator, Akt. Echocardiographic studies showed only a nonsignificant trend toward improved myocardial performance associated with VT. Finally, we evaluated survival in this mouse model. Pretreatment with VT improved survival by 41.4% ( n = 15/group, P = 0.02) and post-LPS administration of VT improved survival by 33.3% ( n = 15/group, P = 0.051). VT-mediated protection from LPS lethality was lost in Tie-2 heterozygous mice, in agreement with VT's proposed receptor specificity. We conclude that this synthetic Tie-2 agonist, completely unrelated to endogenous Tie-2 ligands, is sufficient to activate the receptor and its downstream pathways in vivo and that the Tie-2 receptor may be an important target for therapeutic evaluation in conditions of pathological vascular leakage.

scholarly journals Matrix Metalloproteinase-9 Mediates Hypoxia-Induced Vascular Leakage in the Brain via Tight Junction Rearrangement

2009 ◽  
Vol 30 (4) ◽  
pp. 837-848 ◽  
Author(s):  
Alexander T Bauer ◽  
Heinrich F Bürgers ◽  
Tamer Rabie ◽  
Hugo H Marti
Keyword(s):  
Inflammatory Responses ◽  
Vascular Leakage ◽  
Vascular Endothelial ◽  
Gap Formation ◽  
Edema Formation ◽  
Mmp Inhibitor ◽  
Vascular Structures ◽  
Endothelial Growth Factor ◽  
Metalloproteinase 9

Blood–brain barrier (BBB) disruption, resulting from loss of tight junctions (TJ) and activation of matrix metalloproteinases (MMPs), is associated with edema formation in ischemic stroke. Cerebral edema develops in a phasic manner and consists of both vasogenic and cytotoxic components. Although it is contingent on several independent mechanisms, involving hypoxic and inflammatory responses, the single effect of prolonged hypoxia on BBB integrity in vivo was not addressed so far. Exposing mice to normobaric hypoxia (8% oxygen for 48 h) led to a significant increase in vascular permeability associated with diminished expression of the TJ protein occludin. Immunofluorescence studies revealed that hypoxia resulted in disrupted continuity of occludin and zonula occludens-1 (Zo-1) staining with significant gap formation. Hypoxia increased gelatinolytic activity specifically in vascular structures and gel zymography identified MMP-9 as enzymatic source. Treatment with an MMP inhibitor reduced vascular leakage and attenuated disorganization of TJ. Inhibition of vascular endothelial growth factor (VEGF) attenuated vascular leakage and MMP-9 activation induced by hypoxia. In conclusion, our data suggest that hypoxia-induced edema formation is mediated by MMP-9-dependent TJ rearrangement by a mechanism involving VEGF. Therefore, inhibition of MMP-9 might provide the basis for therapeutic strategies to treat brain edema.

cAMP protects endothelial barrier functions by preventing Rac-1 inhibition

2004 ◽  
Vol 287 (6) ◽  
pp. H2427-H2433 ◽  
Author(s):  
J. Waschke ◽  
D. Drenckhahn ◽  
R. H. Adamson ◽  
H. Barth ◽  
F. E. Curry
Keyword(s):  
Barrier Properties ◽  
Endothelial Barrier ◽  
Vascular Endothelial ◽  
Protective Effects ◽  
Rho Proteins ◽  
Gap Formation ◽  
Barrier Functions ◽  
Mesenteric Microvessels

cAMP enhances endothelial barrier properties and is protective against various inflammatory mediators both in vivo and in vitro. However, the mechanisms whereby cAMP stabilizes the endothelial barrier are largely unknown. Recently we demonstrated that the Rho family GTPase Rac-1 is required for maintenance of endothelial barrier functions in vivo and in vitro. Therefore, in the present study we investigated the effect of forskolin (5 μM)- and rolipram (10 μM)-induced cAMP increase on reduction of barrier functions in response to Rac-1 inhibition by Clostridium sordellii lethal toxin (LT). Forskolin and rolipram treatment blocked LT (200 ng/ml)-induced hydraulic conductivity ( Lp) increase in mesenteric microvessels in vivo. Likewise, LT-induced intercellular gap formation in monolayers of cultured microvascular myocardial endothelial (MyEnd) cells and LT-induced loss of adhesion of vascular endothelial cadherin-coated microbeads were abolished. Inhibition of PKA by myristoylated inhibitor peptide (14–22) of PKA (100 μM) reduced the protective effect of cAMP on LT-induced Lp increase in vivo and gap formation in vitro, indicating that the effect of cAMP on Rac-1 inhibition was PKA dependent. Glucosylation assays demonstrated that cAMP prevents inhibitory Rac-1 glucosylation by LT, indicating that one way that cAMP enhances endothelial barrier functions may be by regulating Rac-1 signaling. Our study suggests that cAMP may provide its well-established protective effects at least in part by regulation of Rho proteins.

scholarly journals Inhibition of Hippo Signaling Improves Skin Lesions in a Rosacea-Like Mouse Model

2021 ◽  
Vol 22 (2) ◽  
pp. 931
Author(s):  
Jihyun Lee ◽  
Yujin Jung ◽  
Seo won Jeong ◽  
Ga Hee Jeong ◽  
Gue Tae Moon ◽  
...  
Keyword(s):  
Mouse Model ◽  
Signaling Pathway ◽  
Normal Skin ◽  
Skin Lesions ◽  
Hippo Signaling ◽  
Vascular Endothelial ◽  
Expression Levels ◽  
Hippo Signaling Pathway ◽  
Endothelial Growth Factor

The Hippo signaling pathway plays a key role in regulating organ size and tissue homeostasis. Hippo and two of its main effectors, yes-associated protein (YAP) and WWTR1 (WW domain-containing transcription regulator 1, commonly listed as TAZ), play critical roles in angiogenesis. This study investigated the role of the Hippo signaling pathway in the pathogenesis of rosacea. We performed immunohistochemical analyses to compare the expression levels of YAP and TAZ between rosacea skin and normal skin in humans. Furthermore, we used a rosacea-like BALB/c mouse model induced by LL-37 injections to determine the roles of YAP and TAZ in rosacea in vivo. We found that the expression levels of YAP and TAZ were upregulated in patients with rosacea. In the rosacea-like mouse model, we observed that the clinical features of rosacea, including telangiectasia and erythema, improved after the injection of a YAP/TAZ inhibitor. Additionally, treatment with a YAP/TAZ inhibitor reduced the expression levels of YAP and TAZ and diminished vascular endothelial growth factor (VEGF) immunoreactivity in the rosacea-like mouse model. Our findings suggest that YAP/TAZ inhibitors can attenuate angiogenesis associated with the pathogenesis of rosacea and that both YAP and TAZ are potential therapeutic targets for patients with rosacea.

ACTH depletion represses vascular endothelial-cadherin transcription in mouse adrenal endothelium in vivo

2005 ◽  
Vol 34 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Philippe Huber ◽  
Christine Mallet ◽  
Elodie Faure ◽  
Christine Rampon ◽  
Marie-Hélène Prandini ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Vascular Endothelial ◽  
Flow Cytometry Analysis ◽  
Adhesion Protein ◽  
Adrenal Cells ◽  
Protein Levels ◽  
Vascular Endothelial Cadherin ◽  
Complex Architecture

Vascular endothelial-cadherin (VE-cadherin) is an endothelial cell-specific adhesion protein that is localised at cell–cell contacts. This molecule is an important determinant of vascular architecture and endothelial cell survival. In the adrenal cortex, steroidogenic and endothelial cells form a complex architecture. The adrenocorticotrophin hormone (ACTH) regulates gland homeostasis whose secretion is subjected to a negative feedback by adrenocorticosteroids. The aim of the present study was to determine whether VE-cadherin expression in the adrenal gland was regulated by hormonal challenge. We demonstrated that VE-cadherin protein levels were dramatically decreased (23.5 ± 3.7%) by dexamethasone injections in the mouse and were restored by ACTH within 7 days (94.9 ± 18.6%). Flow cytometry analysis of adrenal cells showed that the ratios of endothelial versus total adrenal cells were identical (35%) in dexamethasone- or ACTH-treated or untreated mice, suggesting that VE-cadherin expression could be regulated by ACTH. We demonstrate the existence of a transcriptional regulation of the VE-cadherin gene using transgenic mice carrying the chloramphenicol acetyl transferase gene under the control of the VE-cadherin promoter. Indeed, the promoter activity in the adrenals, but not in the lung or liver, was decreased in response to dexamethasone treatment (40 ± 1.3%) and was partially restored after gland regeneration by ACTH injection (82 ± 3%). In conclusion, our results show that transcription of a specific endothelial gene is controlled by the hypothalamo–pituitary axis and the data expand the knowledge regarding the role of ACTH in the regulation of the adrenal vascular network.

scholarly journals Inhibition of endothelial FAK activity prevents tumor metastasis by enhancing barrier function

2014 ◽  
Vol 204 (2) ◽  
pp. 247-263 ◽  
Author(s):  
Christine Jean ◽  
Xiao Lei Chen ◽  
Ju-Ock Nam ◽  
Isabelle Tancioni ◽  
Sean Uryu ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Tumor Cell ◽  
Stromal Cells ◽  
Barrier Function ◽  
Tumor Metastasis ◽  
Vascular Endothelial ◽  
Vascular Endothelial Cadherin ◽  
Tumor Growth And Metastasis ◽  
Endothelial Growth Factor

Pharmacological focal adhesion kinase (FAK) inhibition prevents tumor growth and metastasis, via actions on both tumor and stromal cells. In this paper, we show that vascular endothelial cadherin (VEC) tyrosine (Y) 658 is a target of FAK in tumor-associated endothelial cells (ECs). Conditional kinase-dead FAK knockin within ECs inhibited recombinant vascular endothelial growth factor (VEGF-A) and tumor-induced VEC-Y658 phosphorylation in vivo. Adherence of VEGF-expressing tumor cells to ECs triggered FAK-dependent VEC-Y658 phosphorylation. Both FAK inhibition and VEC-Y658F mutation within ECs prevented VEGF-initiated paracellular permeability and tumor cell transmigration across EC barriers. In mice, EC FAK inhibition prevented VEGF-dependent tumor cell extravasation and melanoma dermal to lung metastasis without affecting primary tumor growth. As pharmacological c-Src or FAK inhibition prevents VEGF-stimulated c-Src and FAK translocation to EC adherens junctions, but FAK inhibition does not alter c-Src activation, our experiments identify EC FAK as a key intermediate between c-Src and the regulation of EC barrier function controlling tumor metastasis.

scholarly journals Endothelial CD47 Promotes Vascular Endothelial-Cadherin Tyrosine Phosphorylation and Participates in T Cell Recruitment at Sites of Inflammation In Vivo

2012 ◽  
Vol 189 (5) ◽  
pp. 2553-2562 ◽  
Author(s):  
Veronica Azcutia ◽  
Michael Stefanidakis ◽  
Naotake Tsuboi ◽  
Tanya Mayadas ◽  
Kevin J. Croce ◽  
...  
Keyword(s):  
T Cell ◽  
Tyrosine Phosphorylation ◽  
Vascular Endothelial ◽  
Cell Recruitment ◽  
Vascular Endothelial Cadherin

The Vascular Endothelial-Cadherin Promoter Directs Endothelial-Specific Expression in Transgenic Mice

Blood ◽  
1999 ◽  
Vol 93 (1) ◽  
pp. 184-192 ◽  
Author(s):  
S. Gory ◽  
M. Vernet ◽  
M. Laurent ◽  
E. Dejana ◽  
J. Dalmon ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Transgenic Mice ◽  
Dna Sequences ◽  
Vascular System ◽  
Proximal Region ◽  
Vascular Endothelial ◽  
Specific Expression ◽  
Functional Regions ◽  
Vascular Endothelial Cadherin

Vascular endothelial-cadherin (VE-cadherin) is a calcium-dependent adhesive molecule, exclusively and constitutively expressed in endothelial cells. Analysis of the VE-cadherin promoter fused to a reporter gene in bovine aortic endothelial cells showed three major functional regions. The proximal region alone (−139, +24) promoted nonspecific transcription; the addition of the (−289, −140) and (−2226, −1190) domains abolished transcription in fibroblasts while expression in endothelial cells remained unchanged, suggesting that fragments (−2226, +24) and longer contain the full endogenous promoter activity. To study the transcriptional specificity of the promoter region in vivo, we generated transgenic mice carrying the chimeric construct containing the (−2486, +24) region. The promoter directed reporter expression in all examined organs of adult transgenic mice. During embryonic development, transgene expression was detected at the early steps of vasculogenesis. Later, the expression persisted during development of the vascular system and was restricted to the endothelial layer of the vessels. Together, these data provide evidence for specific regulatory regions within the VE-cadherinpromoter. Furthermore, the identification of DNA sequences restricting gene expression to the endothelium has many potential applications for the development of animal models of cardiovascular or angiogenic diseases or for the delivery of therapeutic molecules.

Short-term injection of antiapoptotic cytokine combinations soon after lethal γ-irradiation promotes survival

Blood ◽  
2003 ◽  
Vol 101 (7) ◽  
pp. 2609-2616 ◽  
Author(s):  
Francis Hérodin ◽  
Philippe Bourin ◽  
Jean-François Mayol ◽  
Jean-Jacques Lataillade ◽  
Michel Drouet
Keyword(s):  
Lethal Dose ◽  
Survival Rates ◽  
Protective Effects ◽  
Γ Irradiation ◽  
Term Survival ◽  
Hematopoietic Stem ◽  
Better Than

Recovery from radiation-induced (RI) myelosuppression depends on hematopoietic stem and progenitor cell survival and the active proliferation/differentiation process, which requires early cytokine support. Single cytokine or late-acting growth factor therapy has proved to be inefficient in ensuring reconstitution after severe RI damage. This work was aimed at evaluating the in vivo survival effect of combinations of early-acting cytokines whose antiapoptotic activity has been demonstrated in vitro: stem cell factor (SCF [S]), FMS-like tyrosine kinase 3 ligand (FLT-3 ligand [F]), thrombopoietin (TPO [T]), interleukin-3 (IL-3 [3]), and stromal derived factor-1 (SDF-1). B6D2F1 mice underwent total body irradiation at 8 Gy cesium Cs 137 γ radiation (ie, lethal dose 90% at 30 days) and were treated soon after irradiation, at 2 hours and at 24 hours, with recombinant murine cytokines, each given intraperitoneally at 50 μg/kg per injection. All treatments induced 30-day survival rates significantly higher than control (survival rate, 8.3%). 4F (SFT3) and 5F (4F + SDF-1) were the most efficient combinations (81.2% and 87.5%, respectively), which was better than 3F (SFT, 50%), TPO alone (58.3%), and SDF-1 alone (29.2%) and also better than 4F given at 10 μg/kg per injection (4F10, 45.8%) or as a 50 μg/kg single injection at 2 hours (4Fs, 62.5%). Despite delayed death occurring mainly from day 150 on and possible long-term hematopoiesis impairment, half the 30-day protective effects of 4F and 5F were preserved at 300 days. Our results show that short- and long-term survival after irradiation depends on appropriate multiple cytokine combinations and at optimal concentrations. The proposal is made that an emergency cytokine regimen could be applied to nuclear accident victims as part of longer cytokine treatment, cell therapy, or both.

scholarly journals The polyanionic drug suramin neutralizes histones and prevents endotheliopathy

2021 ◽  
Author(s):  
Nuria Villalba ◽  
Adrian M Sackheim ◽  
Michael A Lawson ◽  
Laurel Haines ◽  
Yen Lin Chen ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Electrostatic Interactions ◽  
Lethal Dose ◽  
Lung Edema ◽  
Vascular Endothelial ◽  
Excessive Bleeding ◽  
Therapeutic Implications ◽  
Histone Octamer ◽  
Inflammatory Conditions

Drugs are needed to protect against the neutrophil derived histones responsible for endothelial injury in acute inflammatory conditions such as trauma and sepsis. Heparin and other polyanions can neutralize histones but may cause secondary, deleterious effects such as excessive bleeding. Here, we demonstrate that suramin (a widely available polyanionic drug) completely neutralizes the toxic effects of histones. The sulfate groups on suramin form stable electrostatic interactions with hydrogen bonds in the histone octamer with a dissociation constant of 250 nM. In cultured endothelial cells (Ea.Hy926), histone induced thrombin generation was significantly decreased by suramin. In isolated murine blood vessels, suramin abolished aberrant endothelial cell calcium signals and rescued impaired endothelial dependent vasodilation caused by histones. Suramin significantly decreased pulmonary endothelial cell ICAM-1 expression and neutrophil recruitment caused by infusion of sublethal doses of histones in vivo. Suramin also prevented lung edema, intraalveolar hemorrhage and mortality in mice receiving a lethal dose of histones. Protection of vascular endothelial function from histone-induced damage is a novel mechanism of action for suramin with therapeutic implications for conditions characterized by elevated histone levels.

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