scholarly journals Endothelial Focal Adhesion Kinase Depletion Augments Lung Vascular Permeability by Impairing Sphingosine‐1‐Phosphate Receptor‐1 Function

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Tracy Thennes ◽  
Nebojsa Knezevic ◽  
Mohammad Tauseef ◽  
Seppo Yla‐Herttuala ◽  
Tang‐Long Shen ◽  
...  
2009 ◽  
Vol 206 (12) ◽  
pp. 2761-2777 ◽  
Author(s):  
Nebojsa Knezevic ◽  
Mohammad Tauseef ◽  
Tracy Thennes ◽  
Dolly Mehta

The inflammatory mediator thrombin proteolytically activates protease-activated receptor (PAR1) eliciting a transient, but reversible increase in vascular permeability. PAR1-induced dissociation of Gα subunit from heterotrimeric Gq and G12/G13 proteins is known to signal the increase in endothelial permeability. However, the role of released Gβγ is unknown. We now show that impairment of Gβγ function does not affect the permeability increase induced by PAR1, but prevents reannealing of adherens junctions (AJ), thereby persistently elevating endothelial permeability. We observed that in the naive endothelium Gβ1, the predominant Gβ isoform is sequestered by receptor for activated C kinase 1 (RACK1). Thrombin induced dissociation of Gβ1 from RACK1, resulting in Gβ1 interaction with Fyn and focal adhesion kinase (FAK) required for FAK activation. RACK1 depletion triggered Gβ1 activation of FAK and endothelial barrier recovery, whereas Fyn knockdown interrupted with Gβ1-induced barrier recovery indicating RACK1 negatively regulates Gβ1-Fyn signaling. Activated FAK associated with AJ and stimulated AJ reassembly in a Fyn-dependent manner. Fyn deletion prevented FAK activation and augmented lung vascular permeability increase induced by PAR1 agonist. Rescuing FAK activation in fyn−/− mice attenuated the rise in lung vascular permeability. Our results demonstrate that Gβ1-mediated Fyn activation integrates FAK with AJ, preventing persistent endothelial barrier leakiness.


1997 ◽  
Vol 324 (2) ◽  
pp. 481-488 ◽  
Author(s):  
Fang WANG ◽  
Catherine D. NOBES ◽  
Alan HALL ◽  
Sarah SPIEGEL

Sphingosine 1-phosphate (SPP), a sphingolipid second messenger implicated in the mitogenic action of platelet-derived growth factor [Olivera, A. and Spiegel, S. (1993) Nature (London) 365, 557–560], induced rapid reorganization of the actin cytoskeleton resulting in stress-fibre formation. SPP also induced transient tyrosine phosphorylation of focal adhesion kinase (p125FAK), a cytosolic tyrosine kinase that localizes in focal adhesions, and of the cytoskeleton-associated protein paxillin. Exoenzyme C3 transferase, which ADP-ribosylates Rho (a Ras-related small GTP binding protein) on asparagine-41 and renders it biologically inactive, inhibited both stress-fibre formation and protein tyrosine phosphorylation induced by SPP. Thus Rho may be an upstream regulator of both stress-fibre formation and tyrosine phosphorylation of p125FAK and paxillin. Pretreatment with PMA, an activator of protein kinase C (PKC), inhibited the stimulation of stress-fibre formation induced by 1-oleoyl-lysophosphatidic acid (LPA) but not that by SPP. Similarly, PMA also decreased LPA-induced tyrosine phosphorylation of p125FAK and paxillin without abrogating the response to SPP. Thus PKC is involved in LPA- but not SPP-dependent signalling. The polyanionic drug suramin, a broad-specificity inhibitor of ligand–receptor interactions, did not inhibit either the mitogenic effect of SPP or its stimulation of tyrosine phosphorylation of p125FAK. However, suramin markedly inhibited these responses induced by LPA. These results suggest that in contrast with LPA, SPP may be acting intracellularly in Swiss 3T3 fibroblasts to stimulate tyrosine phosphorylation of p125FAK and paxillin and cell growth.


2018 ◽  
Vol 8 (3) ◽  
pp. 204589401879400 ◽  
Author(s):  
Sharon Rounds ◽  
Qing Lu

Smoking of tobacco products continues to be widespread, despite recent progress in decreasing use. Both in the United States and worldwide, cigarette smoking is a major cause of morbidity and mortality. Growing evidence indicates that acute respiratory distress syndrome (ARDS) is among the consequences of cigarette smoking. Based on the topic from the 2017 Grover Conference, we review evidence that cigarette smoking increases lung vascular permeability using both acute and longer exposures of mice to cigarette smoke (CS). We also review studies indicating that CS extract disrupts cultured lung endothelial cell barrier function through effects on focal adhesion contacts, adherens junctions, actin cytoskeleton, and microtubules. Among the potentially injurious components of CS, the reactive aldehyde, acrolein, similarly increases lung vascular permeability and disrupts barrier function. We speculate that inhibition of aldehyde-induced lung vascular permeability may prevent CS-induced lung injury.


2009 ◽  
Vol 297 (4) ◽  
pp. C945-C954 ◽  
Author(s):  
Kei Sarai ◽  
Kenichi Shikata ◽  
Yasushi Shikata ◽  
Kazuyoshi Omori ◽  
Naomi Watanabe ◽  
...  

Recently, sphingosine 1-phosphate (S1P) has been highlighted as an endothelial barrier-stabilizing mediator. FTY720 is a S1P analog originally developed as a novel immunosuppressant. The phosphorylated form of FTY720 binds to S1P receptors to exert S1P-like biological effects, suggesting endothelial barrier promotion by FTY720. To elucidate whether FTY720 induces signaling events related to endothelial barrier enhancement under hyperglycemic conditions, human microvascular endothelial cells (HMVECs) preincubated with hyperglycemic (30 mM) medium were treated with 100 nM FTY720 for 3 h. Immunofluorescent microscopy and coprecipitation study revealed FTY720-induced focal adhesion kinase (FAK)-associated adherens junction (AJ) assembly at cell-cell contacts coincident with formation of a prominent cortical actin ring. FTY720 also induced transmonolayer electrical resistance (TER) augmentation in HMVEC monolayers in both normoglycemic and hyperglycemic conditions, implying endothelial barrier enhancement. Similar to S1P, site-specific FAK tyrosine phosphorylation analysis revealed FTY720-induced FAK [Y576] phosphorylation without phosphorylation of FAK [Y397/Y925]. Furthermore, FTY720 conditioned the phosphorylation profile of FAK [Y397/Y576/Y925] in hyperglycemic medium to the same pattern observed in normoglycemic medium. FTY720 challenge resulted in small GTPase Rac activation under hyperglycemic conditions, whereas increased Rho activity in hyperglycemic medium was restored to the basal level. Rac protein depletion by small interfering RNA (siRNA) technique completely abolished FTY720-induced FAK [Y576] phosphorylation. These findings strongly suggest the barrier protective effect of FTY720 on HMVEC monolayers in hyperglycemic medium via S1P signaling, further implying the possibility of FTY720 as a therapeutic agent of diabetic vascular disorder.


2021 ◽  
Vol 11 (4) ◽  
pp. 204589402110490
Author(s):  
Joseph B. Mascarenhas ◽  
Amir A. Gaber ◽  
Tania M. Larrinaga ◽  
Rachel Mayfield ◽  
Stefanie Novak ◽  
...  

Increases in lung vascular permeability is a cardinal feature of inflammatory disease and represents an imbalance in vascular contractile forces and barrier-restorative forces, with both forces highly dependent upon the actin cytoskeleton. The current study investigates the role of Ena-VASP-like (EVL), a member of the Ena-VASP family known to regulate the actin cytoskeleton, in regulating vascular permeability responses and lung endothelial cell barrier integrity. Utilizing changes in transendothelial electricial resistance (TEER) to measure endothelial cell barrier responses, we demonstrate that EVL expression regulates endothelial cell responses to both sphingosine-1-phospate (S1P), a vascular barrier-enhancing agonist, and to thrombin, a barrier-disrupting stimulus. Total internal reflection fluorescence demonstrates that EVL is present in endothelial cell focal adhesions and impacts focal adhesion size, distribution, and the number of focal adhesions generated in response to S1P and thrombin challenge, with the focal adhesion kinase (FAK) a key contributor in S1P-stimulated EVL-transduced endothelial cell but a limited role in thrombin-induced focal adhesion rearrangements. In summary, these data indicate that EVL is a focal adhesion protein intimately involved in regulation of cytoskeletal responses to endothelial cell barrier-altering stimuli. Keywords: cytoskeleton, vascular barrier, sphingosine-1-phosphate, thrombin, focal adhesion kinase (FAK), Ena-VASP like protein (EVL), cytoskeletal regulatory protein


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