Anchoring fusion thrombomodulin to the endothelial lumen protects against injury-induced lung thrombosis and inflammation.

Abstract

RATIONALE:

Endothelial thrombomodulin (TM) regulates thrombosis and inflammation. Diverse forms of pulmonary and vascular injury are accompanied by down-regulation of TM, which aggravates tissue injury. We postulated that anchoring TM to the endothelial surface would restore its protective functions.

OBJECTIVES:

To design an effective and safe strategy to treat pulmonary thrombotic and inflammatory injury.

METHODS:

We synthesized a fusion protein, designated scFv/TM, by linking the extracellular domain of mouse TM to a single-chain variable fragment of an antibody to platelet endothelial cell adhesion molecule-1 (PECAM-1). The targeting and protective functions of scFv/TM were tested in mouse models of lung ischemia-reperfusion and acute lung injury (ALI) caused by intratracheal endotoxin and hyperoxia, both of which caused approximately 50% reduction in the endogenous expression of TM.

MEASUREMENTS AND MAIN RESULTS:

Biochemical assays showed that scFv/TM accelerated protein C activation by thrombin and bound mouse PECAM-1 and cytokine high mobility group-B1. After intravenous injection, scFv/TM preferentially accumulated in the mouse pulmonary vasculature. In a lung model of ischemia-reperfusion injury, scFv/TM attenuated elevation of early growth response-1, inhibited pulmonary deposition of fibrin and leukocyte infiltration, and preserved blood oxygenation more effectively than soluble TM. In an ALI model, scFv/TM, but not soluble TM, suppressed activation of nuclear factor-kappaB, inflammation and edema in the lung and reduced mortality without causing hemorrhage.

CONCLUSIONS:

Targeting TM to the endothelium using an scFv anchor enhances its antithrombotic and antiinflammatory effectiveness in models of ALI.

• Authors: Bi-Sen Ding, Nankang Hong, Melpo Christofidou-Solomidou, Claudia Gottstein, Steven M Albelda, Douglas B Cines, Aron B Fisher, Vladimir R Muzykantov
• Journal: American journal of respiratory and critical care medicine (Am J Respir Crit Care Med) Vol. 180 Issue 3 Pg. 247-56 (Aug 01 2009) ISSN: 1535-4970 [Electronic] United States
• PMID: 19342415 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Membrane Fusion Proteins
• Platelet Endothelial Cell Adhesion Molecule-1
• Protein C
• Thrombomodulin

Topics

• Acute Lung Injury (etiology, metabolism)
• Animals
• Disease Models, Animal
• Endothelium (metabolism, pathology)
• Inflammation (metabolism, pathology)
• Membrane Fusion Proteins
• Mice
• Mice, Inbred BALB C
• Platelet Endothelial Cell Adhesion Molecule-1 (metabolism)
• Protein C (metabolism)
• Pulmonary Embolism (complications, metabolism)
• Respiratory Mucosa (metabolism, pathology)
• Thrombomodulin (genetics, metabolism)