pH and temperature modulate norepinephrine-dependent changes in endothelial permeability

To evaluate the role of pH and temperature in norepinephrine (NE)-mediated decreases in endothelial permeability, we studied bovine pulmonary arterial endothelial monolayers at pH values of 4–9 and at temperatures of 35–39 degrees C. Only extremes of pH-modulated endothelial permeability and temperature had no effect. Although both NE and 3-isobutyl-1-methylxanthine decreased endothelial permeability, their effects were diminished by low pH and high temperature. Fever and acidosis may contribute to the edema seen in septic shock by a novel mechanism: attenuation of the barrier-improving function of NE.

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TNF-α-induced matrix Fn disruption and decreased endothelial integrity are independent of Fn proteolysis

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1998.275.1.l126 ◽

1998 ◽

Vol 275 (1) ◽

pp. L126-L138 ◽

Cited By ~ 6

Author(s):

Theresa M. Curtis ◽

Robert F. Rotundo ◽

Peter A. Vincent ◽

Paula J. McKeown-Longo ◽

Thomas M. Saba

Keyword(s):

Extracellular Matrix ◽

Endothelial Permeability ◽

Fragmentation Pattern ◽

Endothelial Monolayers ◽

Tnf Α ◽

The Matrix ◽

Pulmonary Arterial ◽

Permeability Increase ◽

Endothelial Integrity ◽

Protein Permeability

Exposure of confluent pulmonary arterial endothelial monolayers to tumor necrosis factor (TNF)-α causes both a reorganization and/or disruption of fibronectin (Fn) in the extracellular matrix and an increase in transendothelial protein permeability. However, the factors initiating this response to TNF-α have not been defined. Because TNF-α can induce proteinase expression in endothelial cells, we determined whether proteinases cause both the alteration of the Fn matrix and the permeability increase as is often speculated. Incubation of calf pulmonary arterial endothelial monolayers with TNF-α (200 U/ml) for 18 h caused a disruption of the Fn matrix and an increase in transendothelial protein permeability. A reduced colocalization of cell-surface α5β1-Fn integrins with the Fn fibers in focal contacts was also observed. TNF-α treatment of endothelial monolayers with matrices prelabeled with125I-human Fn (hFn) did not cause the release of Fn fragments or alter the content of Fn antigen in the medium as analyzed by SDS-PAGE coupled with autoradiography. Both the content and fragmentation pattern of Fn within the cell layer and the insoluble Fn matrix also appeared unchanged after TNF-α exposure as confirmed by Western immunoblot. Fn-substrate zymography revealed that TNF-α increased the expression of two proteinases within the conditioned medium in which activity could be blocked by aprotinin but not by EDTA, 1,10-phenanthroline, leupeptin, or pepstatin. However, inhibition of the Fn proteolytic activity of these two serine proteinases did not prevent either the TNF-α-induced disruption of the Fn matrix or the increase in permeability. Thus the reorganization and/or disruption of the Fn matrix and the temporally associated increase in endothelial permeability caused by TNF-α appear not to be due to proteolytic degradation of Fn within the extracellular matrix. In contrast, decreased α5β1-Fn integrin interaction with Fn fibers in the matrix may be important in the response to TNF-α exposure.

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Permeability and calcium signaling in lung endothelium: unpack the box…

Pulmonary Circulation ◽

10.1177/2045893217738218 ◽

2017 ◽

Vol 8 (1) ◽

pp. 204589321773821 ◽

Cited By ~ 3

Author(s):

Mary I. Townsley

Keyword(s):

Endothelial Permeability ◽

Blood Leukocytes ◽

Endothelial Monolayers ◽

Yield Information ◽

Specific Permeability ◽

Teaching Point ◽

Lung Endothelium ◽

The Many ◽

Background Context

This brief review assesses the role of Ca2+ signaling in lung endothelium in regulation of endothelial permeability. The disconnect between experimental and clinical outcomes to date may be due, in part, to the use of tools which yield information about aggregate permeability or Ca2+ responses in lung or in endothelial monolayers. The teaching point of this review is to “unpack the box,” i.e. consider the many potential issues which could impact interpretation of outcomes. These include phenotypic heterogeneity and resultant segment-specific permeability responses, methodologic issues related to permeability measures, contributions from Ca2+ channels in cells other than endothelium—such as alveolar macrophages or blood leukocytes), Ca2+ dynamic patterns, rather than averaged Ca2+ responses to channel activation, and the background context, such as changes in endothelial bioenergetics with sepsis. Any or all of these issues might color interpretation of permeability and Ca2+ signaling in lung.

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Leukotriene B4 increases pulmonary transvascular filtration by a neutrophil-independent mechanism

Journal of Applied Physiology ◽

10.1152/jappl.1990.68.3.1260 ◽

1990 ◽

Vol 68 (3) ◽

pp. 1260-1264 ◽

Cited By ~ 6

Author(s):

C. A. Burgess ◽

B. K. McCandless ◽

J. A. Cooper ◽

A. B. Malik

Keyword(s):

Leukotriene B4 ◽

Base Line ◽

Plasma Protein Concentration ◽

Protein Clearance ◽

Endothelial Monolayers ◽

Pulmonary Hemodynamic ◽

Microvascular Response ◽

Pulmonary Arterial

We examined the role of circulating granulocytes in the pulmonary microvascular response to leukotriene B4 (LTB4) by prior depletion of circulating granulocytes using hydroxyurea. LTB4 (2 micrograms/kg injection followed by infusion of 2 micrograms/kg over 15 min) produced transient increases in pulmonary arterial pressure and pulmonary vascular resistance, indicating that neutrophils were not required for the pulmonary hemodynamic effects of LTB4. Infusion of LTB4 in granulocyte-depleted sheep also resulted in transient increases in pulmonary lymph flow (QL) with no significant change in the lymph-to-plasma protein concentration ratio (L/P), findings similar to those in control animals. In vitro studies indicated that LTB4 (10(-7) or 10(-9) M) produced a transient adherence of neutrophils to cultured pulmonary artery endothelial monolayers. Maximal responses occurred at 10 min after the addition of LTB4 to the endothelial cell-neutrophil coculture system, and the adherence decreased to base line within 60 min. LTB4 infusion in sheep also produced a transient uptake of autologous 111In-oxine-labeled neutrophils. The results indicate that LTB4-mediated increase in pulmonary transvascular protein clearance (QL x L/P) is independent of circulating granulocytes.

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VE-PTP stabilizes VE-cadherin junctions and the endothelial barrier via a phosphatase-independent mechanism

The Journal of Cell Biology ◽

10.1083/jcb.201807210 ◽

2019 ◽

Vol 218 (5) ◽

pp. 1725-1742 ◽

Cited By ~ 5

Author(s):

Vanessa V. Juettner ◽

Kevin Kruse ◽

Arkaprava Dan ◽

Vinh H. Vu ◽

Yousaf Khan ◽

...

Keyword(s):

Fluorescent Protein ◽

Tyrosine Phosphatase ◽

Endothelial Permeability ◽

Adaptor Protein ◽

Vascular Endothelial ◽

Rhoa Activity ◽

Endothelial Monolayers ◽

Internalization Rate ◽

Rhoa Signaling

Vascular endothelial (VE) protein tyrosine phosphatase (PTP) is an endothelial-specific phosphatase that stabilizes VE-cadherin junctions. Although studies have focused on the role of VE-PTP in dephosphorylating VE-cadherin in the activated endothelium, little is known of VE-PTP’s role in the quiescent endothelial monolayer. Here, we used the photoconvertible fluorescent protein VE-cadherin-Dendra2 to monitor VE-cadherin dynamics at adherens junctions (AJs) in confluent endothelial monolayers. We discovered that VE-PTP stabilizes VE-cadherin junctions by reducing the rate of VE-cadherin internalization independently of its phosphatase activity. VE-PTP serves as an adaptor protein that through binding and inhibiting the RhoGEF GEF-H1 modulates RhoA activity and tension across VE-cadherin junctions. Overexpression of the VE-PTP cytosolic domain mutant interacting with GEF-H1 in VE-PTP–depleted endothelial cells reduced GEF-H1 activity and restored VE-cadherin dynamics at AJs. Thus, VE-PTP stabilizes VE-cadherin junctions and restricts endothelial permeability by inhibiting GEF-H1, thereby limiting RhoA signaling at AJs and reducing the VE-cadherin internalization rate.

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Role for anions in pulmonary endothelial permeability

Journal of Applied Physiology ◽

10.1152/jappl.1997.83.2.615 ◽

1997 ◽

Vol 83 (2) ◽

pp. 615-622 ◽

Cited By ~ 3

Author(s):

M. Pamela Griffin

Keyword(s):

Phosphodiesterase Inhibitor ◽

Endothelial Permeability ◽

Anion Transport ◽

Transport Processes ◽

Disulfonic Acid ◽

Channel Blockers ◽

Adrenergic Stimulation ◽

Endothelial Monolayers ◽

Wide Range ◽

Pulmonary Arterial

Griffin, M. Pamela. Role for anions in pulmonary endothelial permeability. J. Appl. Physiol. 83(2): 615–622, 1997.—β-Adrenergic stimulation reduces albumin permeation across pulmonary artery endothelial monolayers and induces changes in cell morphology that are mediated by Cl− flux. We tested the hypothesis that anion-mediated changes in endothelial cells result in changes in endothelial permeability. We measured permeation of radiolabeled albumin across bovine pulmonary arterial endothelial monolayers when the extracellular anion was Cl−, Br−, I−, F−, acetate (Ac−), gluconate (G−), and propionate (Pr−). Permeability to albumin ( P albumin) was calculated before and after addition of 0.2 mM of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), which reduces permeability. In Cl−, the P albumin was 3.05 ± 0.86 × 10−6 cm/s and fell by 70% with the addition of IBMX. The initial P albumin was lowest for Pr− and Ac−. Initial P albumin was higher in Br−, I−, G−, and F− than in Cl−. A permeability ratio was calculated to examine the IBMX effect. The greatest IBMX effect was seen when Cl− was the extracellular anion, and the order among halide anions was Cl− > Br− > I− > F−. Although the level of extracellular Ca2+ concentration ([Ca2+]o) varied over a wide range in the anion solutions, [Ca2+]odid not systematically affect endothelial permeability in this system. When Cl− was the extracellular anion, varying [Ca2+]ofrom 0.2 to 2.8 mM caused a change in initial P albumin but no change in the IBMX effect. The anion channel blockers 4-acetamido-4′-isothiocyanotostilbene-2,2′-disulfonic acid (0.25 mM) and anthracene-9-carboxylic acid (0.5 mM) significantly altered initial P albumin and the IBMX effect. The anion transport blockers bumetanide (0.2 mM) and furosemide (1 mM) had no such effects. We conclude that extracellular anions influence bovine pulmonary arterial endothelial permeability and that the pharmacological profile fits better with the activity of anion channels than with other anion transport processes.

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