scholarly journals Lysophosphatidylcholine impairs endothelial barrier function through the G protein-coupled receptor GPR4

2006 ◽  
Vol 291 (1) ◽  
pp. L91-L101 ◽  
Author(s):  
Jing Qiao ◽  
Fei Huang ◽  
Ram P. Naikawadi ◽  
Kwang S. Kim ◽  
Tamer Said ◽  
...  

Abundant evidence indicates that lysophosphatidylcholine (LPC) is proinflammatory and atherogenic. In the vascular endothelium, LPC increases permeability and expression of proinflammatory molecules such as adhesion molecules and cytokines. Yet, mechanisms by which LPC mediates these activities remain unclear and controversial. Recent evidence implicates involvement of a novel subfamily of G protein-coupled receptors (GPR4, G2A, OGR1, and TDAG8) that are sensitive to lysolipids and protons. We previously reported that one of these receptors, GPR4, is selectively expressed by a variety of endothelial cells and therefore hypothesize that the LPC-stimulated endothelial barrier dysfunction is mediated through GPR4. We developed a peptide Ab against GPR4 that detected GPR4 expression in transfected COS 7 cells and endogenous GPR4 expression in endothelial cells by Western blot. Endothelial cells infected with a retrovirus containing small interference RNA (siRNA) to GPR4 resulted in 40–50% decreased GPR4 expression, which corresponded with partial prevention of the LPC-induced 1) decrease in transendothelial resistance, 2) stress fiber formation, and 3) activation of RhoA. Furthermore, coexpression of the siRNA-GPR4 with a siRNA-resistant mutant GPR4 fully restored the LPC-induced resistance decrease. However, extracellular pH of <7.4 did not alter baseline or LPC-stimulated resistances. The results provide strong evidence that the LPC-mediated endothelial barrier dysfunction is regulated by endogenous GPR4 in endothelial cells and suggest that GPR4 may play a critical role in the inflammatory responses activated by LPC.

2016 ◽  
Vol 311 (1) ◽  
pp. L39-L47 ◽  
Author(s):  
Jinyan Yu ◽  
Zhongsen Ma ◽  
Sreerama Shetty ◽  
Mengshi Ma ◽  
Jian Fu

Lung endothelial damage contributes to the pathogenesis of acute lung injury. New strategies against lung endothelial barrier dysfunction may provide therapeutic benefits against lung vascular injury. Cell-cell junctions and microtubule cytoskeleton are basic components in maintaining endothelial barrier integrity. HDAC6, a deacetylase primarily localized in the cytoplasm, has been reported to modulate nonnuclear protein function through deacetylation. Both α-tubulin and β-catenin are substrates for HDAC6. Here, we examined the effects of tubastatin A, a highly selective HDAC6 inhibitor, on TNF-α induced lung endothelial cell barrier disruption and endotoxin-induced pulmonary edema. Selective HDAC6 inhibition by tubastatin A blocked TNF-α-induced lung endothelial cell hyperpermeability, which was associated with increased α-tubulin acetylation and microtubule stability. Tubastatin A pretreatment inhibited TNF-α-induced endothelial cell contraction and actin stress fiber formation with reduced myosin light chain phosphorylation. Selective HDAC6 inhibition by tubastatin A also induced β-catenin acetylation in human lung endothelial cells, which was associated with increased membrane localization of β-catenin and stabilization of adherens junctions. HDAC6 knockdown by small interfering RNA also prevented TNF-α-induced barrier dysfunction and increased α-tubulin and β-catenin acetylation in endothelial cells. Furthermore, in a mouse model of endotoxemia, tubastatin A was able to prevent endotoxin-induced deacetylation of α-tubulin and β-catenin in lung tissues, which was associated with reduced pulmonary edema. Collectively, our data indicate that selective HDAC6 inhibition by tubastatin A is a potent approach against lung endothelial barrier dysfunction.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Maura Knapp ◽  
Mei Zheng ◽  
Nikola Sladojevic ◽  
Qiong Zhao ◽  
Konstaintin G Birukov ◽  
...  

Background: Diabetes leads to endothelial barrier dysfunction and altered endothelial permeability, which results in increased cardiovascular risk. ARNT, also known as HIF-1β, a transcription factor that functions as a master regulator of glucose homeostasis, has been implicated in diabetes. Endothelial-specific ARNT deletion (ArntΔEC) in mice is embryonically lethal, with hemorrhage occurring in the heart during the embryonic stage. However, the particular role of endothelial ARNT(ecARNT) in diabetes is largely unknown. We have found a significant decrease in ARNT expression in both diabetic rodent endothelial cells and diabetic human hearts. We hypothesize that a loss of ecARNT mediates endothelial barrier dysfunction during diabetes. Methods and Results: We generated inducible endothelial specific ARNT knockout mice (ecARNT-/-) by crossing mice with loxP sequences flanking exon 6 of ARNT with Cre ERT2 mice under the VE-cadherin promoter. A 90% deletion of ecARNT was achieved following two weeks of oral tamoxifen administration. ecARNT-/- mice exhibit severe blood vessel leakage, which is restricted to the heart, suggesting a distinct function for ecARNT in different tissues. Cardiomyopathy is evident 6 months after ARNT deletion. In vitro , trans-endothelial electrical resistance (TER) and transwell assays have confirmed endothelial barrier disruption in cardiac microvascular endothelial cells (CMEC) isolated from both ecARNT-/- hearts and diabetic (DB/DB) mouse hearts. To determine the underlying mechanisms by which ARNT may regulate endothelial barrier function, we performed DNA sequencing on CMEC isolated from control, ecARNT-/-, and DB/DB mice. Data suggest a significant increase in TNFa signaling, including ELAM-1 and ICAM-1 in CMEC isolated from ecARNT-/- CMEC and diabetic CMEC. Moreover, use of anti-TNFa antibody rescues endothelial barrier dysfunction in CMEC isolated from ecARNT-/- mice. Taken together, these results suggest that a reduction in ecARNT during diabetes may mediate endothelial barrier dysfunction through a TNFa signaling pathway. Conclusion: ecARNT is a critical mediator of endothelial barrier function and could potentially serve as a therapeutic target for diabetic cardiovascular diseases.


2014 ◽  
Vol 306 (8) ◽  
pp. C745-C752 ◽  
Author(s):  
Vladislav V. Makarenko ◽  
Peter V. Usatyuk ◽  
Guoxiang Yuan ◽  
May M. Lee ◽  
Jayasri Nanduri ◽  
...  

The objective of the present study was to determine the impact of simulated apnea with intermittent hypoxia (IH) on endothelial barrier function and assess the underlying mechanism(s). Experiments were performed on human lung microvascular endothelial cells exposed to IH-consisting alternating cycles of 1.5% O2 for 30s followed by 20% O2 for 5 min. IH decreased transendothelial electrical resistance (TEER) suggesting attenuated endothelial barrier function. The effect of IH on TEER was stimulus dependent and reversible after reoxygenation. IH-exposed cells exhibited stress fiber formation and redistribution of cortactin, vascular endothelial-cadherins, and zona occludens-1 junction proteins along with increased intercellular gaps at cell-cell boundaries. Extracellular signal-regulated kinase (ERK) and c-jun NH2-terminal kinase (JNK) were phosphorylated in IH-exposed cells. Inhibiting either ERK or JNK prevented the IH-induced decrease in TEER and the reorganization of the cytoskeleton and junction proteins. IH increased reactive oxygen species (ROS) levels, and manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride, a membrane-permeable antioxidant, prevented ERK and JNK phosphorylation as well as IH-induced changes in endothelial barrier function. These results demonstrate that IH via ROS-dependent activation of MAP kinases leads to reorganization of cytoskeleton and junction proteins resulting in endothelial barrier dysfunction.


Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1489
Author(s):  
Ruben M. L. Colunga Biancatelli ◽  
Pavel Solopov ◽  
Betsy Gregory ◽  
John D. Catravas

Exposure to hydrochloric acid (HCl) leads acutely to asthma-like symptoms, acute respiratory distress syndrome (ARDS), including compromised alveolo-capillary barrier, and respiratory failure. To better understand the direct effects of HCl on pulmonary endothelial function, we studied the characteristics of HCl-induced endothelial barrier dysfunction in primary cultures of human lung microvascular endothelial cells (HLMVEC), defined the involved molecular pathways, and tested the potentially beneficial effects of Heat Shock Protein 90 (HSP90) inhibitors. HCl impaired barrier function in a time- and concentration-dependent manner and was associated with activation of Protein Kinase B (AKT), Ras homolog family member A (RhoA) and myosin light chain 2 (MLC2), as well as loss of plasmalemmal VE-cadherin, rearrangement of cortical actin, and appearance of inter-endothelial gaps. Pre-treatment or post-treatment of HLMVEC with AUY-922, a third-generation HSP90 inhibitor, prevented and restored HCl-induced endothelial barrier dysfunction. AUY-922 increased the expression of HSP70 and inhibited the activation (phosphorylation) of extracellular-signal regulated kinase (ERK) and AKT. AUY-922 also prevented the HCl-induced activation of RhoA and MLC2 and the internalization of plasmalemmal VE-cadherin. We conclude that, by increasing the expression of cytoprotective proteins, interfering with actomyosin contractility, and enhancing the expression of junction proteins, inhibition of HSP90 may represent a useful approach for the management of HCl-induced endothelial dysfunction and acute lung injury.


Endocrinology ◽  
2012 ◽  
Vol 154 (2) ◽  
pp. 727-737 ◽  
Author(s):  
Zhenquan Jia ◽  
Wei Zhen ◽  
Pon Velayutham Anandh Babu ◽  
Dongmin Liu

The soy-derived phytoestrogen genistein has received attention for its potential to improve vascular function, but its mechanism remains unclear. Here, we report that genistein at physiologically relevant concentrations (0.1–10 μM) significantly inhibited thrombin-induced increase in endothelial monolayer permeability. Genistein also reduced the formation of stress fibers by thrombin and suppressed thrombin-induced phosphorylation of myosin light chain (MLC) on Ser19/Thr18 in endothelial cells (ECs). Genistein had no effect on resting intracellular [Ca2+] or thrombin-induced increase in Ca2+ mobilization. Addition of the inhibitors of endothelial nitric oxide synthase or estrogen receptor did not alter the protective effect of genistein. RhoA is a small GTPase that plays an important role in actin-myosin contraction and endothelial barrier dysfunction. RhoA inhibitor blocked the protective effect of genistein on endothelial permeability and also ablated thrombin-induced MLC-phosphorylation in ECs. Inhibition of PKA significantly attenuated the effect of genistein on thrombin-induced EC permeability, MLC phosphorylation, and RhoA membrane translocation in ECs. Furthermore, thrombin diminished cAMP production in ECs, which were prevented by treatment with genistein. These findings demonstrated that genistein improves thrombin-induced endothelial barrier dysfunction in ECs through PKA-mediated suppression of RhoA signaling.


Sign in / Sign up

Export Citation Format

Share Document