Soluble vascular endothelial glycocalyx proteoglycans as potential therapeutic targets in inflammatory diseases

Reducing the activity of cytokines and leukocyte extravasation is an emerging therapeutic strategy to limit tissue-damaging inflammatory responses and restore immune homeostasis in inflammatory diseases. Proteoglycans embedded in the vascular endothelial glycocalyx, which regulate the activity of cytokines to restrict the inflammatory response in physiological conditions, are proteolytically cleaved in inflammatory diseases. Here we critically review the potential of proteolytically shed, soluble vascular endothelial glycocalyx proteoglycans to modulate pathological inflammatory responses. Soluble forms of the proteoglycans syndecan-1, syndecan-3 and biglycan exert beneficial anti-inflammatory effects by the removal of chemokines, suppression of proinflammatory cytokine expression and leukocyte migration, and induction of autophagy of proinflammatory M1 macrophages. By contrast, soluble versikine and decorin enhance proinflammatory responses by increasing inflammatory cytokine synthesis and leukocyte migration. Endogenous syndecan-2 and mimecan exert proinflammatory effects, syndecan-4 and perlecan mediate beneficial anti-inflammatory effects and glypican regulates Hh and Wnt signaling pathways involved in systemic inflammatory responses. Taken together, targeting the vascular endothelial glycocalyx-derived, soluble syndecan-1, syndecan-2, syndecan-3, syndecan-4, biglycan, versikine, mimecan, perlecan, glypican and decorin might be a potential therapeutic strategy to suppress overstimulated cytokine and leukocyte responses in inflammatory diseases.

Biomolecular interactions between the antibacterial ceftolozane and the human inflammatory disease target ADAM17: a drug repurposing study

Inhibition of a disintegrin and metalloproteinase-17 (ADAM17), a metzincin, is proposed as a novel therapeutic strategy to suppress overproduction of the proinflammatory cytokine TNF-α in rheumatoid arthritis and inflammatory bowel disease. Existing ADAM17 inhibitors generate toxic metabolites in-vivo or haven't progressed in clinical trials. Previous studies suggest that ligands which bind to ADAM17 active site by interacting with the Zn ion and L-shaped hydrophobic S1'- and S3'-pockets and forming favorable hydrogen bonds could act as potential ADAM17 inhibitors. Here, we investigated whether the FDA-approved anti-bacterial drug ceftolozane, a cephalosporin containing aromatic groups and carboxyl groups as probable zinc binding groups (ZBGs), forms non-covalent interactions resulting in its binding in the active site of ADAM17. In this study, the density functional theory (DFT), molecular docking and molecular dynamics calculations with the catalytic chain of ADAM17 show that carboxyl group of ceftolozane acts as moderate ZBG, and its extended geometry forms hydrogen bonds and hydrophobic interactions resulting in a binding affinity comparable to the co-crystallized known ADAM17 inhibitor. The favorable binding interactions identified here suggest the potential of ceftolozane to modulate ADAM17 activity in inflammatory diseases. ADAM17 cleaves and releases epidermal growth factor (EGF) ligands from the cell surface. The shed EGF ligands then bind to the EGF receptors to drive embryonic development. Therefore, our findings also suggest that use of ceftolozane during pregnancy may inhibit ADAM17-mediated shedding of EGF and thus increase the risk of birth defects in humans.Communicated by Ramaswamy H. Sarma.

Improved method for surgical induction of chronic hypertension in mice

Chronic hypertension can be induced in mice by one-kidney one-clip (1K1C) or two-kidney one-clip surgery, transgenic overexpression of angiotensinogen and renin, administration of deoxycorticosterone acetate-salt, supplying Nitro-L-arginine methyl-ester in the drinking water and Angiotensin-II infusion. Although each model has its own pros and cons, selection of a model that mimics human hypertensive disease accurately is essential to ensure rigor and reproducibility in hypertension research. 1K1C mice represent an efficient, budget-friendly, and translationally capable model; however, their use in preclinical research has remained largely hindered due to concerns about potential technical complexity and lack of reported information regarding procedure-related mortality rates. Here, we describe in detail an improved version of the 1K1C surgery in mice that has zero intraoperative mortality and excellent survival rates in a long-term setting and permits the development of stable chronic hypertension and its target organ complications. Key to this outcome is unilateral nephrectomy 1 week after renal artery clipping to decelerate the blood pressure (BP) increase, which allows the organism to adapt better to the BP rise. The technical and animal welfare improvements presented here may promote the acceptance of the 1K1C model.

LB0003 WITHDRAWING METHOTREXATE AFTER BOTH VERSUS ONLY SECOND DOSE OF THE ChAdOx1 nCoV-19 VACCINE IN PATIENTS WITH AUTOIMMUNE INFLAMMATORY ARTHRITIS: TWO INDEPENDENT RANDOMIZED CONTROLLED TRIALS (MIVAC I AND II)

Background

Pausing methotrexate (MTX) for two to four weeks, improved immunogenicity of influenza vaccination in patients with rheumatoid arthritis (RA), albeit a risk of disease flare (1). This guided the framing of guidelines on MTX withdrawal for COVID-19 vaccination (2). However, evidence for MTX withdrawal for COVID-19 vaccination is limited to observational studies only.

Objectives

To compare the efficacy and safety of holding MTX after each (MIVAC 1) and only after the second dose (MIVAC II) of the ChAdOx1 vaccine versus continuation of MTX in two randomized controlled trials (RCTs).

Methods

Two single centre, investigator-blinded, RCTs were conducted in patients with RA or Psoriatic arthritis (PsA) on stable doses of MTX without prior COVID-19 (CTRI reg. no. MIVAC I: CTRI/2021/07/03463 & MIVAC II: CTRI/2021/07/035307). In MIVAC I, unvaccinated patients were randomised (1:1) to hold or continue MTX for two weeks after each dose of the vaccine. MIVAC II included patients who had continued MTX during the first dose of ChAdOx1 and were randomised (1:1) to hold or continue MTX for 2 weeks after the second vaccine dose. The primary outcome for both the trials was the anti-Receptor Binding Domain (RBD) antibody titres measured four weeks after the second vaccine dose (per protocol analysis). Secondary outcome was the flare rate, defined as an increase in disease activity scores (DAS28/cDAPSA) or physician intent to hike DMARDs.

Results

250 patients were randomized for MIVAC 1 and 178 for MIVAC II and after due exclusions, 158 and 157 were eligible for analysis respectively (Figure 1). In MIVAC I, median anti-RBD titres were significantly high in the MTX hold group [2484 (1050-4388) versus 1147(433-2360), p=0.001] but the flare rate was higher in the hold group [20 (25%) versus 6(8%) p=0.005] compared to continue group. In MIVAC II median anti-RBD titres were significantly high for the MTX hold group [2553 (1792-4823) versus 990 (356-2252), p=0.001] when compared to continue group but there was no difference in the flare rate between the groups [9(11.8%) and 4(7.9%), p=0.15] (Table 1). Since both were parallel studies in similar population, MTX hold arms across both the trials were compared for anti-RBD titres and flare. There was no difference in the anti-RBD titres [p=0.2] between the groups. In MIVAC I, 29(36.25%) patients had reported flare (19 in either first or second dose, 10 for both doses) when compared to MIVAC II where only 9(11.84%) patients had reported flare after the second dose (P <0.001).

Table 1.

Baseline demographics and key results

VariableMIVAC IMIVAC IIMTX HoldMTX ContinuePMTX HoldMTX ContinueP valueN=80N=78valueN=76N=81Age†48 (38-53.3)49 (39-59)0.1953 (42.3-59)53(50-62)0.14Female (%) ‡73 (91.3)75 (96.2)0.3365 (85.5)70 (86.4)>0.99RA (%) ‡69(86.3)69 (93.2)70 (85.6)80 (87.7)PsA (%) ‡11(13.8)6 (8.1)0.316 (7.9)1 (1.2)0.057DAS28†2.7 (2.4-3.2)2.6 (2-3.3)0.62.7(2.3-3.4)2.8 (2.1-3.5)0.78cDAPSA †2(3-4.5)2.5(1.3-3.8)0.463(2.8-3)30.15Prednisolone (%) ‡29 (36.3)23(31.1)0.424(31.6)26 (32.1)>0.99MTX mg/week†17.5 (10-25)15 (10-20)0.05715 (9.4-25)17.5(7.5-25)0.92Anti- RBD antibody titres post second dose (IU/mL) †2484 (1050-4388.8)1147.5 (433.5-2360.3)<0.0012553.5 (1792.5-4823.8)990.5 (356.1-2252.5)<0.001Flare (N%) ‡Post first dose20 (25)6 (8)0.005NANAPost second dose19 (23.8)10(13.3)0.19 (11.8)4 (7.9)0.15

All analysis as per protocol population.

†Median (interquartile range): Mann Whitney U test.

‡ N (%): Fisher Exact test

. Bolded if p<0.05.

Conclusion

Holding MTX after both the doses or only after the second dose of ChAdOx1 yields higher anti-RBD antibody titres as compared to continuing MTX. Comparing across the trials, holding MTX only after the second dose appears to be non-inferior to holding MTX after both doses of the vaccine with a lesser risk of flare.

References

[1]Park JK et al. Clin Rheumatol. 2020 Feb; 39(2):375-379.

[2]Curtis JR, et al. Arthritis & Rheumatology. 2021 Oct;73(10): e60-75.

Acknowledgements

Acknowledgments to all participating investigators, patients and their families

Disclosure of Interests

Anu Sreekanth: None declared, Teny Skaria: None declared, Sneha Joseph: None declared, Rashwith Umesh: None declared, Manju Mohanan: None declared, Aby Paul: None declared, Sakir Ahmed Speakers bureau: Sakir Ahmed had received honorarium as speaker from Pfizer, Dr Reddy’s, Cipla, and Novartis unrelated to this Comment, Pankti Mehta: None declared, Seena Oomen: None declared, Janet Benny: None declared, Justin George: None declared, Anagha Paulose: None declared, K Narayanan: None declared, Sanjana Joseph: None declared, Anuroopa Vijayan: None declared, Kaveri Nalianda: None declared, Padmanabha Shenoy: None declared

The Neuropeptide α-Calcitonin Gene-Related Peptide as the Mediator of Beneficial Effects of Exercise in the Cardiovascular System

Regular physical activity exerts cardiovascular protective effects in healthy individuals and those with chronic cardiovascular diseases. Exercise is accompanied by an increased plasma concentration of α-calcitonin gene-related peptide (αCGRP), a 37-amino acid peptide with vasodilatory effects and causative roles in migraine. Moreover, mouse models revealed that loss of αCGRP disrupts physiological adaptation of the cardiovascular system to exercise in normotension and aggravates cardiovascular impairment in primary chronic hypertension, both can be reversed by αCGRP administration. This suggests that αCGRP agonists could be a therapeutic option to mediate the cardiovascular protective effects of exercise in clinical setting where exercise is not possible or contraindicated. Of note, FDA has recently approved αCGRP antagonists for migraine prophylaxis therapy, however, the cardiovascular safety of long-term anti-CGRP therapy in individuals with cardiovascular diseases has yet to be established. Current evidence from preclinical models suggests that chronic αCGRP antagonism may abolish the cardiovascular protective effects of exercise in both normotension and chronic hypertension.

Novel regulators of airway epithelial barrier function during inflammation: potential targets for drug repurposing

INTRODUCTION

Endogenous inflammatory signaling molecules resulting from deregulated immune responses, can impair airway epithelial barrier function and predispose individuals with airway inflammatory diseases to exacerbations and lung infections. Targeting the specific endogenous factors disrupting the airway barrier therefore has the potential to prevent disease exacerbations without affecting the protective immune responses.

AREAS COVERED

Here, we review the endogenous factors and specific mechanisms disrupting airway epithelial barrier during inflammation and reflect on whether these factors can be specifically targeted by repurposed existing drugs. Literature search was conducted using PubMed, drug database of US FDA and European Medicines Agency until and including September 2021.

EXPERT OPINION

IL-4 and IL-13 signaling are the major pathways disrupting the airway epithelial barrier during airway inflammation. However, blocking IL-4/IL-13 signaling may adversely affect protective immune responses and increase susceptibility of host to infections. An alternate approach to modulate airway epithelial barrier function involves targeting specific downstream component of IL-4/IL-13 signaling or different inflammatory mediators responsible for regulation of airway epithelial barrier. Airway epithelium-targeted therapy using inhibitors of HDAC, HSP90, MIF, mTOR, IL-17A and VEGF may be a potential strategy to prevent airway epithelial barrier dysfunction in airway inflammatory diseases.

Transcriptional Regulation of Drug Metabolizing CYP Enzymes by Proinflammatory Wnt5A Signaling in Human Coronary Artery Endothelial Cells

Downregulation of drug metabolizing enzymes and transporters by proinflammatory mediators in hepatocytes, enterocytes and renal tubular epithelium is an established mechanism affecting pharmacokinetics. Emerging evidences indicate that vascular endothelial cell expression of drug metabolizing enzymes and transporters may regulate pharmacokinetic pathways in heart to modulate local drug bioavailability and toxicity. However, whether inflammation regulates pharmacokinetic pathways in human cardiac vascular endothelial cells remains largely unknown. The lipid modified protein Wnt5A is emerging as a critical mediator of proinflammatory responses and disease severity in sepsis, hypertension and COVID-19. In the present study, we employed transcriptome profiling and gene ontology analyses to investigate the regulation of expression of drug metabolizing enzymes and transporters by Wnt5A in human coronary artery endothelial cells. Our study shows for the first time that Wnt5A induces the gene expression of CYP1A1 and CYP1B1 enzymes involved in phase I metabolism of a broad spectrum of drugs including chloroquine (the controversial drug for COVID-19) that is known to cause toxicity in myocardium. Further, the upregulation of CYP1A1 and CYP1B1 expression is preserved even during inflammatory crosstalk between Wnt5A and the prototypic proinflammatory IL-1β in human coronary artery endothelial cells. These findings stimulate further studies to test the critical roles of vascular endothelial cell CYP1A1 and CYP1B1, and the potential of vascular-targeted therapy with CYP1A1/CYP1B1 inhibitors in modulating myocardial pharmacokinetics in Wnt5A-associated inflammatory and cardiovascular diseases.

CGRP Receptor Antagonism in COVID-19: Potential Cardiopulmonary Adverse Effects

Recently, the US FDA has authorized a drug repurposing trial with calcitonin gene-related peptide (CGRP) receptor antagonists to reduce lung inflammation in coronavirus 2019 (COVID-19). However, the well-established cardiopulmonary protective effects of CGRP raise concerns about the safety of antagonizing CGRP in COVID-19. Awareness regarding potential cardiopulmonary adverse effects may enable their early detection and prevent illness from worsening.

Blood Pressure Normalization-Independent Cardioprotective Effects of Endogenous, Physical Activity-Induced αCGRP (α Calcitonin Gene-Related Peptide) in Chronically Hypertensive Mice

RATIONALE

αCGRP (α calcitonin gene-related peptide), one of the strongest vasodilators, is cardioprotective in hypertension by reducing the elevated blood pressure.

OBJECTIVE

However, we hypothesize that endogenous, physical activity-induced αCGRP has blood pressure-independent cardioprotective effects in chronic hypertension.

METHODS AND RESULTS

Chronically hypertensive (one-kidney-one-clip surgery) wild-type and αCGRP^-/- sedentary or voluntary wheel running mice were treated with vehicle, αCGRP, or the αCGRP receptor antagonist CGRP8-37. Cardiac function and myocardial phenotype were evaluated echocardiographically and by molecular, cellular, and histological analysis, respectively. Blood pressure was similar among all hypertensive experimental groups. Endogenous αCGRP limited pathological remodeling and heart failure in sedentary, chronically hypertensive wild-type mice. In these mice, voluntary wheel running significantly improved myocardial phenotype and function, which was abolished by CGRP8-37 treatment. In αCGRP^-/- mice, αCGRP treatment, in contrast to voluntary wheel running, improved myocardial phenotype and function. Specific inhibition of proliferation and myofibroblast differentiation of primary, murine cardiac fibroblasts by αCGRP suggests involvement of these cells in αCGRP-dependent blunting of pathological cardiac remodeling.

CONCLUSIONS

Endogenous, physical activity-induced αCGRP has blood pressure-independent cardioprotective effects and is crucial for maintaining cardiac function in chronic hypertension. Consequently, inhibiting endogenous αCGRP signaling, as currently approved for migraine prophylaxis, could endanger patients with hypertension.

P4475Vasodilation- and blood pressure normalization-independent cardioprotective effects of endogenous, physical activity-induced alpha calcitonin gene-related peptide in chronic hypertension

Background

Alpha calcitonin gene-related peptide (αCGRP) is one of the strongest vasodilators and, as such, is cardioprotective in chronic hypertension when reducing the associated elevated blood pressure. However, we hypothesize that endogenous, physical activity-induced αCGRP has blood pressure independent cardioprotective effects in chronic hypertension.

Methods

Chronic hypertension was induced in WT and αCGRP−/− mice by one-kidney one-clip surgery. Chronic hypertensive WT and αCGRP−/− mice lived sedentarily or performed voluntary wheel running and were treated simultaneously with either vehicle, αCGRP or αCGRP receptor antagonist CGRP8–37. Cardiac function and tissue phenotype were evaluated echocardiographically and by ddPCR, Western blotting and histology, respectively.

Results

Blood pressure was similar among all hypertensive experimental groups. Endogenous αCGRP limited pathological cardiac remodeling and symptomatic heart failure already in sedentary, chronic hypertensive WT mice. In these mice, voluntary wheel running significantly improved cardiac tissue phenotype and function, that was abolished by CGRP8–37 treatment. In αCGRP−/− mice, αCGRP treatment, in contrast to voluntary wheel running, improved cardiac tissue phenotype and function. Specific inhibition of proliferation and myofibroblast differentiation of primary murine cardiac fibroblasts by αCGRP suggests involvement of these cells in αCGRP-mediated blunting of pathological cardiac remodeling.

Conclusion

Endogenous, physical activity-induced αCGRP has blood pressure independent cardioprotective effects and is crucial for maintaining cardiac function in chronic hypertension. Consequently, permanently inhibiting endogenous αCGRP signaling, as currently approved for migraine prophylaxis, could endanger hypertensive patients.

Acknowledgement/Funding

Swiss National Science Foundation, Novartis Foundation for Medical-biological Research

RSPO3 impairs barrier function of human vascular endothelial monolayers and synergizes with pro-inflammatory IL-1

BACKGROUND

Endothelial barrier dysfunction characterized by hyperpermeability of the vascular endothelium is a key factor in the pathogenesis of chronic inflammatory diseases and affects clinical outcomes. In states of chronic inflammation, mediators secreted by activated immune cells or vascular endothelium may affect the barrier function and permeability of the vascular endothelium. The matricellular R-spondin family member RSPO3 is produced by inflammatory-activated human monocytes and vascular endothelial cells, but its effects in the regulation of vascular endothelial barrier function remains elusive.

METHODS

The present study investigates the effects of RSPO3 on the barrier function of adult human primary macro- and micro- vascular endothelial monolayers. Tight monolayers of primary endothelial cells from human coronary and pulmonary arteries, and cardiac, brain, and dermal microvascular beds were treated with RSPO3 either alone or in combination with pro-inflammatory mediator IL-1β. Endothelial barrier function was assessed non-invasively in real-time using Electric Cell-substrate Impedance Sensing.

RESULTS

RSPO3 treatment critically affected barrier function by enhancing the permeability of all vascular endothelial monolayers investigated. To confer hyperpermeable phenotype in vascular endothelial monolayers, RSPO3 induced inter-endothelial gap formation by disrupting the β-catenin and VE-cadherin alignment at adherens junctions. RSPO3 synergistically enhanced the barrier impairing properties of the pro-inflammatory mediator IL-1β.

CONCLUSION

Here, we show that the matricellular protein RSPO3 is a mediator of endothelial hyperpermeability that can act in synergy with the inflammatory mediator IL-1β. This finding stimulates further studies to delineate the endothelial barrier impairing properties of RSPO3 and its synergistic interaction with IL-1β in chronic inflammatory diseases.

Inflammatory Wnt5A signalling pathways affecting barrier function of human vascular endothelial cells

Wnt5A is a chemokine secreted by inflammatory-activated human macrophages that sustains their inflammatory response in an autocrine manner. High levels of Wnt5A are found in sera of patients with sepsis and septic shock. Here, we comment on recently reported Wnt5A signalling pathways in human vascular endothelial cells (VEC). In human VEC, Wnt5A regulates cytoskeleton remodelling and barrier function through Ryk receptor and Rho-associated protein serine/threonine kinase, targeting LIMK2 and CFL1 involved in actin polymerisation. Wnt5A/Ryk signalling in VEC can be antagonised by the naturally occurring Wnt inhibitory factor (WIF)-1 (WIF1). Therapeutic targeting of this mechanism may reduce vascular leakage and edema in severe systemic inflammation and therefore should be subject of further investigations.

WIF1 prevents Wnt5A mediated LIMK/CFL phosphorylation and adherens junction disruption in human vascular endothelial cells

Background

Wnt5A is released by activated macrophages and elevated levels have been detected in sepsis patients with severe systemic inflammation. However, the signalling and functional effects of Wnt5A in the vascular endothelial cells (VEC) remained unclear. Recently, we showed that Wnt5A affects barrier function in human VEC through Ryk interaction. Wnt5A/Ryk signalling activates LIMK to inactivate the actin depolymerisation factor CFL by phosphorylation, promotes actin polymerisation and disrupts endothelial adherens junctions.

Findings

Here, we investigate the antagonistic effect of the Ryk specific secreted Wnt antagonist Wnt inhibitory factor (WIF)-1 on Wnt5A-mediated activation/inactivation of LIMK/CFL, and adherens junction disruption in human VEC. In human coronary artery endothelial cells (HCAEC), treatment with Wnt5A enhanced the phosphorylation of LIMK and CFL that was significantly prevented by WIF1. The presence of WIF1 suppressed Wnt5A-mediated disruption of β-catenin and VE-cadherin adherens junctions in HCAEC, thereby preventing barrier dysfunction caused by Wnt5A.

Conclusion

We conclude that WIF1 or molecules with similar properties could be potent tools for the prevention of vascular leakage due to Wnt5A-mediated actin cytoskeleton remodeling in diseases associated with systemic inflammation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12950-017-0157-4) contains supplementary material, which is available to authorized users.

IL-4 Causes Hyperpermeability of Vascular Endothelial Cells through Wnt5A Signaling

Microvascular leakage due to endothelial barrier dysfunction is a prominent feature of T helper 2 (Th2) cytokine mediated allergic inflammation. Interleukin-4 (IL-4) is a potent Th2 cytokine, known to impair the barrier function of endothelial cells. However, the effectors mediating IL-4 induced cytoskeleton remodeling and consequent endothelial barrier dysfunction remain poorly defined. Here we have used whole genome transcriptome profiling and gene ontology analyses to identify the genes and processes regulated by IL-4 signaling in human coronary artery endothelial cells (HCAEC). The study revealed Wnt5A as an effector that can mediate actin cytoskeleton remodeling in IL-4 activated HCAEC through the regulation of LIM kinase (LIMK) and Cofilin (CFL). Following IL-4 treatment, LIMK and CFL were phosphorylated, thereby indicating the possibility of actin stress fiber formation. Imaging of actin showed the formation of stress fibers in IL-4 treated live HCAEC. Stress fiber formation was notably decreased in the presence of Wnt inhibitory factor 1 (WIF1). Non-invasive impedance measurements demonstrated that IL-4 increased the permeability and impaired the barrier function of HCAEC monolayers. Silencing Wnt5A significantly reduced permeability and improved the barrier function of HCAEC monolayers upon IL-4 treatment. Our study identifies Wnt5A as a novel marker of IL-4 activated vascular endothelium and demonstrates a critical role for Wnt5A in mediating IL-4 induced endothelial barrier dysfunction. Wnt5A could be a potential therapeutic target for reducing microvascular leakage and edema formation in Th2 driven inflammatory diseases.

Wnt5A/Ryk signaling critically affects barrier function in human vascular endothelial cells

Satisfactory therapeutic strategies for septic shock are still missing. Previously we found elevated levels of Wnt5A in patients with severe sepsis and septic shock. Wnt5A is released by activated macrophages but knowledge of its effects in the vascular system remains scant. Here we investigate the response of human coronary artery endothelial cells (HCAEC) to Wnt5A. We used a genome-wide differential expression approach to define novel targets regulated by Wnt5A. Gene ontology analysis of expression profiles revealed clusters of genes involved in actin cytoskeleton remodeling as the predominant targets of Wnt5A. Wnt5A targeted Rho-associated protein serine/threonine kinase (ROCK), leading to phosphorylation of LIM kinase-2 (LIMK2) and inactivation of the actin depolymerization factor cofilin-1 (CFL1). Functional experiments recording cytoskeletal rearrangements in living cells showed that Wnt5A enhanced stress fiber formation as a consequence of reduced actin depolymerization. The antagonist Wnt inhibitory factor 1 (WIF1) that specifically interferes with the WIF domain of Ryk receptors prevented actin polymerization. Wnt5A disrupted β-catenin and VE-cadherin adherens junctions forming inter-endothelial gaps. Functional experiments targeting the endothelial monolayer integrity and live recording of trans-endothelial resistance revealed enhanced permeability of Wnt5A-treated HCAEC. Ryk silencing completely prevented Wnt5A-induced endothelial hyperpermeability. Wnt5A decreased wound healing capacity of HCAEC monolayers; this was restored by the ROCK inhibitor Y-27632. Here we show that Wnt5A acts on the vascular endothelium causing enhanced permeability through Ryk interaction and downstream ROCK/LIMK2/CFL1 signaling. Wnt5A/Ryk signaling might provide novel therapeutic strategies to prevent capillary leakage in systemic inflammation and septic shock.