scholarly journals Oxidized Phospholipids in Control of Endothelial Barrier Function: Mechanisms and Implication in Lung Injury

2021 ◽  
Vol 12 ◽  
Author(s):  
Pratap Karki ◽  
Konstantin G. Birukov

Earlier studies investigating the pathogenesis of chronic vascular inflammation associated with atherosclerosis described pro-inflammatory and vascular barrier disruptive effects of lipid oxidation products accumulated in the sites of vascular lesion and atherosclerotic plaque. However, accumulating evidence including studies from our group suggests potent barrier protective and anti-inflammatory properties of certain oxidized phospholipids (OxPLs) in the lung vascular endothelium. Among these OxPLs, oxidized 1-palmitoyl-2-arachdonyl-sn-glycero-3-phosphocholine (OxPAPC) causes sustained enhancement of lung endothelial cell (EC) basal barrier properties and protects against vascular permeability induced by a wide variety of agonists ranging from bacterial pathogens and their cell wall components, endotoxins, thrombin, mechanical insults, and inflammatory cytokines. On the other hand, truncated OxPLs cause acute endothelial barrier disruption and potentiate inflammation. It appears that multiple signaling mechanisms triggering cytoskeletal remodeling are involved in OxPLs-mediated regulation of EC barrier. The promising vascular barrier protective and anti-inflammatory properties exhibited by OxPAPC and its particular components that have been established in the cellular and animal models of sepsis and acute lung injury has prompted consideration of OxPAPC as a prototype therapeutic molecule. In this review, we will summarize signaling and cytoskeletal mechanisms involved in OxPLs-mediated damage, rescue, and restoration of endothelial barrier in various pathophysiological settings and discuss a future potential of OxPAPC in treating lung disorders associated with endothelial barrier dysfunction.

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 981 ◽  
Author(s):  
Pratap Karki ◽  
Konstantin G. Birukov

Circulating and cell membrane phospholipids undergo oxidation caused by enzymatic and non-enzymatic mechanisms. As a result, a diverse group of bioactive oxidized phospholipids generated in these conditions have both beneficial and harmful effects on the human body. Increased production of oxidized phospholipid products with deleterious effects is linked to the pathogenesis of various cardiopulmonary disorders such as atherosclerosis, thrombosis, acute lung injury (ALI), and inflammation. It has been determined that the contrasting biological effects of lipid oxidation products are governed by their structural variations. For example, full-length products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine oxidation (OxPAPC) have prominent endothelial barrier protective and anti-inflammatory activities while most of the truncated oxidized phospholipids induce vascular leak and exacerbate inflammation. The extensive studies from our group and other groups have demonstrated a strong potential of OxPAPC in mitigating a wide range of agonist-induced lung injuries and inflammation in pulmonary endothelial cell culture and rodent models of ALI. Concurrently, elevated levels of truncated oxidized phospholipids are present in aged mice lungs that potentiate the inflammatory agents-induced lung injury. On the other hand, increased levels of full length OxPAPC products accelerate ALI recovery by facilitating production of anti-inflammatory lipid mediator, lipoxin A4, and other molecules with anti-inflammatory properties. These findings suggest that OxPAPC-assisted lipid program switch may be a promising therapeutic strategy for treatment of acute inflammatory syndromes. In this review, we will summarize the vascular-protective and deleterious aspects of oxidized phospholipids and discuss their therapeutic potential including engineering of stable analogs of oxidized phospholipids with improved anti-inflammatory and barrier-protective properties.


2015 ◽  
Vol 308 (5) ◽  
pp. L452-L463 ◽  
Author(s):  
Fanyong Meng ◽  
Angelo Meliton ◽  
Nurgul Moldobaeva ◽  
Gokhan Mutlu ◽  
Yoshihiro Kawasaki ◽  
...  

Increased vascular endothelial permeability and inflammation are major pathological mechanisms of pulmonary edema and its life-threatening complication, the acute respiratory distress syndrome (ARDS). We have previously described potent protective effects of hepatocyte growth factor (HGF) against thrombin-induced hyperpermeability and identified the Rac pathway as a key mechanism of HGF-mediated endothelial barrier protection. However, anti-inflammatory effects of HGF are less understood. This study examined effects of HGF on the pulmonary endothelial cell (EC) inflammatory activation and barrier dysfunction caused by the gram-negative bacterial pathogen lipopolysaccharide (LPS). We tested involvement of the novel Rac-specific guanine nucleotide exchange factor Asef in the HGF anti-inflammatory effects. HGF protected the pulmonary EC monolayer against LPS-induced hyperpermeability, disruption of monolayer integrity, activation of NF-kB signaling, expression of adhesion molecules intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, and production of IL-8. These effects were critically dependent on Asef. Small-interfering RNA-induced downregulation of Asef attenuated HGF protective effects against LPS-induced EC barrier failure. Protective effects of HGF against LPS-induced lung inflammation and vascular leak were also diminished in Asef knockout mice. Taken together, these results demonstrate potent anti-inflammatory effects by HGF and delineate a key role of Asef in the mediation of the HGF barrier protective and anti-inflammatory effects. Modulation of Asef activity may have important implications in therapeutic strategies aimed at the treatment of sepsis and acute lung injury/ARDS-induced gram-negative bacterial pathogens.


2015 ◽  
Vol 308 (6) ◽  
pp. L550-L562 ◽  
Author(s):  
Angelo Y. Meliton ◽  
Fanyong Meng ◽  
Yufeng Tian ◽  
Nicolene Sarich ◽  
Gokhan M. Mutlu ◽  
...  

Increased endothelial cell (EC) permeability and vascular inflammation along with alveolar epithelial damage are key features of acute lung injury (ALI). Products of 1-palmitoyl-2-arachidonoyl- sn-glycero-3-phosphorylcholine oxidation (OxPAPC) showed protective effects against inflammatory signaling and vascular EC barrier dysfunction induced by gram-negative bacterial wall lipopolysaccharide (LPS). We explored the more general protective effects of OxPAPC and investigated whether delayed posttreatment with OxPAPC boosts the recovery of lung inflammatory injury and EC barrier dysfunction triggered by intratracheal injection of heat-killed gram-positive Staphylococcus aureus (HKSA) bacteria. HKSA-induced pulmonary EC permeability, activation of p38 MAP kinase and NF-κB inflammatory cascades, secretion of IL-8 and soluble ICAM1, fibronectin deposition, and expression of adhesion molecules ICAM1 and VCAM1 by activated EC were significantly attenuated by cotreatment as well as posttreatment with OxPAPC up to 16 h after HKSA addition. Remarkably, posttreatment with OxPAPC up to 24 h post-HKSA challenge dramatically accelerated lung recovery by restoring lung barrier properties monitored by Evans blue extravasation and protein content in bronchoalveolar lavage (BAL) fluid and reducing inflammation reflected by decreased MIP-1, KC, TNF-α, IL-13 levels and neutrophil count in BAL samples. These studies demonstrate potent in vivo and in vitro protective effects of posttreatment with anti-inflammatory oxidized phospholipids in the model of ALI caused by HKSA. These results warrant further investigations into the potential use of OxPAPC compounds combined with antibiotic therapies as a treatment of sepsis and ALI induced by gram-positive bacterial pathogens.


2007 ◽  
Vol 97 (03) ◽  
pp. 348-354 ◽  
Author(s):  
Valery Bochkov

SummaryLipid oxidation products and in particular oxidized phospholipids (OxPL) are increasingly recognized as inducers of chronic inflammation characteristic of atherosclerosis. OxPL stimulate production of chemokines and adhesion of monocytes to endothelial cells. However, accumulating data suggest that, in addition to the proatherogenic and proinflammatory effects, OxPL can stimulate antiinflammatory and tissue-protective mechanisms. Thus, depending on the biological situation, OxPL can either stimulate or inhibit inflammation. In this review, the inflammatory properties of OxPL are discussed together with the underlying receptor, signalling and transcriptional mechanisms.


Author(s):  
Luis F. Delgadillo ◽  
Elena B. Lomakina ◽  
Julia Kuebel ◽  
Richard E. Waugh

Leukocyte adhesion to the endothelium is an important early step in the initiation and progression of sepsis. The endothelial glycocalyx layer (EGL) has been implicated in neutrophil adhesion and barrier dysfunction, but studies in this area are few. In this report we examine the hypothesis that damage to the structure of the EGL caused by inflammation leads to increased leukocyte adhesion and endothelial barrier dysfunction. We used human umbilical vein endothelial cells (HUVECs) enzymatically treated to remove the EGL components hyaluronic acid (HA) and heparan sulfate (HS) as a model for EGL damage. Using atomic force microscopy, we show reductions in EGL thickness after removal of either HA or HS individually, but the largest decrease, comparable to TNF-a treatment, was observed when both HA and HS were removed. Interestingly, removal of HS or HA individually did not affect neutrophil adhesion significantly, but removal of both constituents resulted in increased neutrophil adhesion. To test EGL contributions to endothelial barrier properties, we measured trans-endothelial electrical resistance (TEER) and diffusion of fluorescently labeled dextran (10 kDa MW) across the monolayer. Removal of EGL components decreased TEER, but had an insignificant effect on dextran diffusion rates. The reduction in TEER suggests that disruption of the EGL may predispose endothelial cells to increased rates of fluid leakage. These data support the view that damage to the EGL during inflammation has significant effects on the accessibility of adhesion molecules, likely facilitates leukocyte adhesion, and may also contribute to increased rates of fluid transport into tissues.


2014 ◽  
Vol 25 (13) ◽  
pp. 2006-2016 ◽  
Author(s):  
Anna A. Birukova ◽  
Patrick A. Singleton ◽  
Grzegorz Gawlak ◽  
Xinyong Tian ◽  
Tamara Mirzapoiazova ◽  
...  

Vascular integrity and the maintenance of blood vessel continuity are fundamental features of the circulatory system maintained through endothelial cell–cell junctions. Defects in the endothelial barrier become an initiating factor in several pathologies, including ischemia/reperfusion, tumor angiogenesis, pulmonary edema, sepsis, and acute lung injury. Better understanding of mechanisms stimulating endothelial barrier enhancement may provide novel therapeutic strategies. We previously reported that oxidized phospholipids (oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine [OxPAPC]) promote endothelial cell (EC) barrier enhancement both in vitro and in vivo. This study examines the initiating mechanistic events triggered by OxPAPC to increase vascular integrity. Our data demonstrate that OxPAPC directly binds the cell membrane–localized chaperone protein, GRP78, associated with its cofactor, HTJ-1. OxPAPC binding to plasma membrane–localized GRP78 leads to GRP78 trafficking to caveolin-enriched microdomains (CEMs) on the cell surface and consequent activation of sphingosine 1-phosphate receptor 1, Src and Fyn tyrosine kinases, and Rac1 GTPase, processes essential for cytoskeletal reorganization and EC barrier enhancement. Using animal models of acute lung injury with vascular hyperpermeability, we observed that HTJ-1 knockdown blocked OxPAPC protection from interleukin-6 and ventilator-induced lung injury. Our data indicate for the first time an essential role of GRP78 and HTJ-1 in OxPAPC-mediated CEM dynamics and enhancement of vascular integrity.


2017 ◽  
Vol 57 (6) ◽  
pp. 662-673 ◽  
Author(s):  
Qing Lu ◽  
Miles Mundy ◽  
Eboni Chambers ◽  
Thilo Lange ◽  
Julie Newton ◽  
...  

Blood ◽  
2020 ◽  
Author(s):  
Mark J McVey ◽  
Sarah Weidenfeld ◽  
Mazharul Maishan ◽  
Chris Spring ◽  
Michael Kim ◽  
...  

Transfusion-related acute lung injury (TRALI) is a hazardous transfusion complication with an associated mortality of 5-15%. We previously showed that stored (5 days; D5) but not fresh platelets (1 day; D1) cause TRALI via ceramide mediated endothelial barrier dysfunction. As biological ceramides are hydrophobic, extracellular vesicles (EVs) may be required to shuttle these sphingolipids from platelets to endothelial cells. Adding to complexity, EV formation in turn requires ceramide. We hypothesized that ceramide-dependent EV formation from stored platelets and EV-dependent sphingolipid shuttling induce TRALI. EVs formed during storage of murine platelets were enumerated, characterized for sphingolipids and applied in a murine TRALI model in vivo and for endothelial barrier assessment in vitro. D5-EVs were more abundant, had higher long chain ceramide (C16:0, C18:0, C20:0) and lower S1P content than D1-EVs. Transfusion of D5- but not D1-EVs induced characteristic signs of lung injury in vivo and endothelial barrier disruption in vitro. Inhibition or supplementation of ceramide-forming sphingomyelinase reduced or enhanced the formation of EVs, respectively, but did not alter the injuriousness per individual EV. Barrier failure was attenuated when EVs were abundant in or supplemented with S1P. Stored human platelet D4-EVs were more numerous compared with D2-EVs, contained more long chain ceramide and less S1P, and caused more EC barrier leak. Hence, platelet-derived EVs become more numerous and more injurious (more long chain ceramide, less S1P) during storage. Blockade of sphingomyelinase, EV elimination, or supplementation of S1P during platelet storage may present promising strategies for TRALI prevention.


Sign in / Sign up

Export Citation Format

Share Document