Incorporation of iloprost in phospholipase-resistant phospholipid scaffold enhances its barrier protective effects on pulmonary endothelium

Olga Oskolkova,Nicolene Sarich,Fanyong Meng,Grzegorz Gawlak,Yufeng Tian,Valery N Bochkov,Evgeny Berdyshev,Anna A Birukova,Konstantin G Birukov

doi:10.1038/s41598-018-19197-1

Abstract

Correction of barrier dysfunction and inflammation in acute lung injury (ALI) represents an important problem. Previous studies demonstrate barrier-protective and anti-inflammatory effects of bioactive lipid prostacyclin and its stable analog iloprost (ILO). We generated a phospholipase resistant synthetic phospholipid with iloprost attached at the sn-2 position (ILO-PC) and investigated its biological effects. In comparison to free ILO, ILO-PC caused sustained endothelial cell (EC) barrier enhancement, linked to more prolonged activation of Rap1 and Rac1 GTPases and their cytoskeletal and cell junction effectors: cortactin, PAK1, p120-catenin and VE-cadherin. ILO and ILO-PC equally efficiently suppressed acute, Rho GTPase-dependent EC hyper-permeability caused by thrombin. However, ILO-PC exhibited more sustained barrier-protective and anti-inflammatory effects in the model of chronic EC dysfunction caused by bacterial wall lipopolysacharide (LPS). ILO-PC was also more potent inhibitor of NFκB signaling and lung vascular leak in the murine model of LPS-induced ALI. Treatment with ILO-PC showed more efficient ALI recovery over 3 days after LPS challenge than free ILO. In conclusion, this study describes a novel synthetic phospholipid with barrier-enhancing and anti-inflammatory properties superior to existing prostacyclin analogs, which may be used as a prototype for future development of more efficient treatment for ALI and other vascular leak syndromes.

Highlights

Pulmonary endothelial cell (EC) barrier precisely regulates transport of fluids and macromolecules across the vessel wall, and EC barrier dysfunction developing during lung infection, injury, and other acute conditions may have devastating consequences such as pulmonary edema and acute respiratory distress syndrome (ARDS)
This study describes for the first time the biological properties of a phospholipase resistant synthetic phospholipid with incorporated iloprost moiety
Uncertain stability and variable composition of oxidized phospholipid preparations represent a serious obstacle in potential therapeutic application of this group of bioactive lipids. These limitations motivated our efforts in design of an individual phospholipid molecule bearing iloprost, a modified prostacyclin characterized by prolonged action

Summary

Introduction

Pulmonary endothelial cell (EC) barrier precisely regulates transport of fluids and macromolecules across the vessel wall, and EC barrier dysfunction developing during lung infection, injury, and other acute conditions may have devastating consequences such as pulmonary edema and acute respiratory distress syndrome (ARDS). Activation of Rac[1] in endothelial cells stimulates peripheral actin polymerization, enforcement of peripheral F-actin rim and increases formation of VE-cadherin-based adherens junctions. These morphological and functional changes lead to enhancement of lung vascular endothelial barrier[5]. Previous studies in the models of acute lung injury and agonist-induced EC barrier dysfunction demonstrated potent and sustained protective effects of oxidized phospholipids bearing iso-prostanoid moiety[12,13,14]. We compared barrier-protective and anti-inflammatory effects of free and phospholipid-bound ILO in human pulmonary EC treated with edemagenic agonist thrombin or bacterial wall lipopolysacharide LPS.

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Results

Conclusion