Control of Vascular Permeability by Atrial Natriuretic Peptide via a GEF-H1-dependent Mechanism

Gawlak

Journal of Biological Chemistry

et al. 2016

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Agonist-induced activation of Rho GTPase signaling leads to endothelial cell (EC) permeability and may culminate in pulmonary edema, a devastating complication of acute lung injury. Cingulin is an adaptor protein first discovered in epithelium and is involved in the organization of the tight junctions. This study investigated the role of cingulin in control of agonist-induced lung EC permeability via interaction with RhoA-specific activator GEF-H1. The siRNA-induced cingulin knockdown augmented thrombin-induced EC permeability monitored by measurements of transendothelial electrical resistance and endothelial cell permeability for macromolecules. Increased thrombin-induced permeability in ECs with depleted cingulin was associated with increased activation of GEF-H1 and RhoA detected in pulldown activation assays. Increased GEF-H1 association with cingulin was essential for down-regulation of thrombin-induced RhoA barrier disruptive signaling. Using cingulin-truncated mutants, we determined that GEF-H1 interaction with the rod ؉ tail domain of cingulin was required for inactivation of GEF-H1 and endothelial cell barrier preservation. The results demonstrate the role for association of GEF-H1 with cingulin as the mechanism of RhoA pathway inactivation and rescue of EC barrier after agonist challenge.

Section: Methodsmentioning

confidence: 99%

Role of Cingulin in Agonist-induced Vascular Endothelial Permeability

Gawlak

Journal of Biological Chemistry

et al. 2016

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American Journal of Physiology-Renal Physiology

“…Refill rate cannot be easily assessed, although a methodology has been developed to measure refill rate in hemodialysis (24). Starling forces primarily determine refill rate and include the permeability of the capillary membrane, which is not fixed but influenced by numerous factors, including ANG II (168), atrial natriuretic peptide (142,153), inflammatory cytokines (23,93), and nitric oxide (NO) (28,149). Characterization of capillary refill in complex states like advanced kidney failure would, therefore, contribute to the understanding of consequences of rapid alterations in volume status with furosemide.…”

Section: F961mentioning

confidence: 99%

Everything we always wanted to know about furosemide but were afraid to ask

Huang

Mees

Vos

et al. 2016

Huang X, Dorhout Mees E, Vos P, Hamza S, Braam B. Everything we always wanted to know about furosemide but were afraid to ask. Am J Physiol Renal Physiol 310: F958 -F971, 2016. First published February 24, 2016 doi:10.1152/ajprenal.00476.2015.-Furosemide is a widely used, potent natriuretic drug, which inhibits the Na ϩ -K ϩ -2Cl Ϫ cotransporter (NKCC)-2 in the ascending limb of the loop of Henle applied to reduce extracellular fluid volume expansion in heart and kidney disease. Undesirable consequences of furosemide, such as worsening of kidney function and unpredictable effects on sodium balance, led to this critical evaluation of how inhibition of NKCC affects renal and cardiovascular physiology. This evaluation reveals important knowledge gaps, involving furosemide as a drug, the function of NKCC2 (and NKCC1), and renal and systemic indirect effects of NKCC inhibition. Regarding renal effects, renal blood flow and glomerular filtration rate could become compromised by activation of tubuloglomerular feedback or by renin release, particularly if renal function is already compromised. Modulation of the intrarenal renin angiotensin system, however, is ill-defined. Regarding systemic effects, vasodilation followed by nonspecific NKCC inhibition and changes in venous compliance are not well understood. Repetitive administration of furosemide induces short-term (braking phenomenon, acute diuretic resistance) and long-term (chronic diuretic resistance) adaptations, of which the mechanisms are not well known. Modulation of NKCC2 expression and activity in kidney and heart failure is ill-defined. Lastly, furosemide's effects on cutaneous sodium stores and on uric acid levels could be beneficial or detrimental. Concluding, a considerable knowledge gap is identified regarding a potent drug with a relatively specific renal target, NKCC2, and renal and systemic actions. Resolving these questions would increase the understanding of NKCCs and their actions and improve rational use of furosemide in pathophysiology of fluid volume expansion. extracellular fluid volume; natriuresis; renal function; chronic kidney disease; heart failure DIURETICS BLOCKING THE Na ϩ -K ϩ -2Cl Ϫ cotransporter (NKCC) have an important place in the treatment of fluid overload, specifically in the context of kidney disease and heart failure (64). Of the drugs that inhibit the NKCC2 in the loop of Henle (furosemide, bumetanide, torsemide, ethacrynic acid), furosemide is most commonly applied (66) and Ͼ40 million prescriptions are dispensed every year in the USA (66a). However, many uncertainties remain about intrarenal and systemic actions of furosemide, including its two main targets NKCC1 and NKCC2.Clinically, there are a number of undesirable consequences of the use of furosemide, of which the pathophysiological mechanisms have not been sufficiently investigated. Furosemide has been associated with worsening of kidney function in patients treated for volume overload admitted for acute heart failure (104) and even glomerular filtration rate (GFR) ...

“…Analysis of EC Permeability-Endothelial permeability to macromolecules was monitored by express permeability testing assay (XPerT) (31,32) available from Millipore (Vascular Permeability Imaging Assay, catalog no. ).…”

Section: Cell Culture and Reagents-human Hgf Was Obtained From Randd Symentioning

confidence: 99%

Hepatocyte Growth Factor-induced Asef-IQGAP1 Complex Controls Cytoskeletal Remodeling and Endothelial Barrier

Journal of Biological Chemistry

Gawlak

Shah

et al. 2015

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Background: Upstream mechanisms of HGF-induced endothelial barrier enhancement are not well understood. Results: HGF induced IQGAP1 interaction with Rac-specific GEF Asef leading to endothelial barrier enhancement. Conclusion: IQGAP1-dependent Asef targeting to cortical cytoskeleton represents a novel mechanism of local regulation of Rac and endothelial barrier function. Significance: Subcellular targeting of small GTPase regulators may represent a novel approach to modulate vascular endothelial permeability.