Fragmented oxidation products define barrier disruptive endothelial cell response to OxPAPC.

Excessive concentrations of oxidized phospholipids (OxPL), the products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (PAPC) oxidation have been detected in atherosclerosis, septic inflammation, and acute lung injury (ALI) and have been shown to induce vascular barrier dysfunction. In contrast, oxidized PAPC (OxPAPC) at low concentrations exhibit potent barrier protective effects. The nature of such biphasic effects remains unclear.

A role for VEGFR2 activation in endothelial responses caused by barrier disruptive OxPAPC concentrations.

Introduction: Oxidation products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (OxPAPC) differentially modulate endothelial cell (EC) barrier function in a dose-dependent fashion. Vascular endothelial growth factor receptor-2 (VEGFR2) is involved in the OxPAPC-induced EC inflammatory activation. This study examined a role of VEGFR2 in barrier dysfunction caused by high concentrations of OxPAPC and evaluated downstream signaling mechanisms resulting from the effect of OxPAPC in EC from pulmonary and systemic circulation.

Differential regulation of endothelial cell permeability by high and low doses of oxidized 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine.

The generation of phospholipid oxidation products in atherosclerosis, sepsis, and lung pathologies affects endothelial barrier function, which exerts significant consequences on disease outcomes in general. Our group previously showed that oxidized 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine (OxPAPC) at low concentrations increases endothelial cell (EC) barrier function, but decreases it at higher concentrations. In this study, we determined the mechanisms responsible for the pulmonary endothelial cell barrier dysfunction induced by high OxPAPC concentrations.

Lipoxin A4 counterregulates GM-CSF signaling in eosinophilic granulocytes.

Eosinophils are granulated leukocytes that are involved in many inflammation-associated pathologies including airway inflammation in asthma. Resolution of eosinophilic inflammation and return to homeostasis is in part due to endogenous chemical mediators, for example, lipoxins, resolvins, and protectins. Lipoxins are endogenous eicosanoids that demonstrate antiinflammatory activity and are synthesized locally at sites of inflammation.

Cross-talk between ICAM-1 and granulocyte-macrophage colony-stimulating factor receptor signaling modulates eosinophil survival and activation.

Reversal of eosinophilic inflammation has been an elusive therapeutic goal in the management of asthma pathogenesis. In this regard, GM-CSF is a primary candidate cytokine regulating eosinophil activation and survival in the lung; however, its molecular mechanism of propagation and maintenance of stimulated eosinophil activation is not well understood. In this study, we elucidate those late interactions occurring between the GM-CSF receptor and activated eosinophil signaling molecules.