Abrogation of thrombin-induced increase in pulmonary microvascular permeability in PAR-1 knockout mice

• Published in: Physiological genomics 2000-12, Vol.4 (2), p.137-145
• Main Authors: VOGEL, STEPHEN M, GAO, XIAOPEI, MEHTA, DOLLY, YE, RICHARD D, JOHN, THERESA A, ANDRADE-GORDON, PATRICIA, TIRUPPATHI, CHINNASWAMY, MALIK, ASRAR B
• Format: Article
• Language: English
• Subjects: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid - pharmacology; Animals; Capillary Permeability - drug effects; Dose-Response Relationship, Drug; Genotype; In Vitro Techniques; Lung - blood supply; Lung - drug effects; Lung - metabolism; Male; Mice; Mice, Knockout; Myosin Light Chains - metabolism; Oligopeptides - pharmacology; Phosphorylation - drug effects; Pulmonary Circulation - drug effects; Receptor, PAR-1; Receptors, Thrombin - genetics; Receptors, Thrombin - physiology; RNA - genetics; RNA - metabolism; Thrombin - pharmacology; Vasoconstrictor Agents - pharmacology
• ISSN: 1094-8341; 1531-2267
• DOI: 10.1152/physiolgenomics.2000.4.2.137

1 Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois 60612 2 The R. W. Johnson Pharmaceutical Research Institute, Spring House, Pennsylvania 19477 We investigated the function of proteinase-activated receptor-1 (PAR-1) in the regulation of pulmonary microvascular permeability in response to thrombin challenge using PAR-1 knockout mice (-/-). Lungs were isolated and perfused with albumin (5 g/100 ml)-Krebs solution at constant flow (2 ml/min). Lung wet weight and pulmonary artery pressure (P pa ) were continuously monitored. We determined the capillary filtration coefficient ( K fc ) and 125 I-labeled albumin (BSA) permeability-surface area product (PS) to assess changes in pulmonary microvessel permeability to liquid and albumin, respectively. Normal and PAR-1-null lung preparations received in the perfusate: 1 ) thrombin or 2 ) selective PAR-1 agonist peptide (TFLLRNPNDK-NH 2 ). In control PAR-1 (+/+) mouse lungs, 125 I-albumin PS and K fc were significantly increased over baseline (by 7- and 1.5-fold, respectively) within 20 min of -thrombin (100 nM) challenge. PAR-1 agonist peptide (5 µM) gave similar results, whereas control peptide (5 µM; FTLLRNPNDK-NH 2 ) was ineffective. At relatively high concentrations, thrombin (500 nM) or PAR-1 agonist peptide (10 µM) also induced increases in P pa and lung wet weight. All effects of thrombin (100 or 500 nM) or PAR-1 agonist peptide (5 or 10 µM) were prevented in PAR-1-null lung preparations. Baseline measures of microvessel permeability and P pa in the PAR-1-null preparations were indistinguishable from those in normal lungs. Moreover, PAR-1-null preparations gave normal vasoconstrictor response to thromboxane analog, U-46619 (100 nM). The results indicate that the PAR-1 receptor is critical in mediating the permeability-increasing and vasoconstrictor effects of thrombin in pulmonary microvessels. proteinase-activated receptor; cultured endothelial cell monolayers; tethered ligand