Coagulation factor Xa activates thrombin in ischemic neural tissue

• Published in: Journal of neurochemistry 2009-11, Vol.111 (3), p.828-836
• Main Authors: Thevenet, Jonathan, Angelillo-Scherrer, Anne, Price, Melanie, Hirt, Lorenz
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Anticoagulants - pharmacology; Biochemistry; Biological and medical sciences; c-Jun; Cell Death - drug effects; Cell physiology; cerebral ischemia; factor Xa; Factor Xa - pharmacology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; Glucose - deficiency; hippocampal slice cultures; Hippocampus - drug effects; Hippocampus - metabolism; Hypoxia - metabolism; Ischemia - pathology; JNK Mitogen-Activated Protein Kinases - metabolism; Medical sciences; Molecular and cellular biology; Neurology; Neurons; Organ Culture Techniques; oxygen and glucose deprivation; Polysaccharides - pharmacology; protease-activated receptor-1; Pyrroles - pharmacology; Quinazolines - pharmacology; Rats; Receptor, PAR-1 - antagonists & inhibitors; Responses to growth factors, tumor promotors, other factors; Rodents; Serine - metabolism; Signal Transduction - drug effects; Stroke; thrombin; Thrombin - antagonists & inhibitors; Thrombin - metabolism; Vascular diseases and vascular malformations of the nervous system
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2009.06369.x

Thrombin is involved in mediating neuronal death in cerebral ischemia. We investigated its so far unknown mode of activation in ischemic neural tissue. We used an in vitro approach to distinguish the role of circulating coagulation factors from endogenous cerebral mechanisms. We modeled ischemic stroke by subjecting rat organotypic hippocampal slice cultures to 30-min oxygen (5%) and glucose (1 mmol/L) deprivation (OGD). Perinuclear activated factor X (FXa) immunoreactivity was observed in CA1 neurons after OGD. Selective FXa inhibition by fondaparinux during and after OGD significantly reduced neuronal death in the CA1 after 48 h. Thrombin enzyme activity was increased in the medium 24 h after OGD and this increase was prevented by fondaparinux suggesting that FXa catalyzes the conversion of prothrombin to thrombin in neural tissue after ischemia in vitro. Treatment with SCH79797, a selective antagonist of the thrombin receptor protease-activated receptor-1 (PAR-1), significantly decreased neuronal cell death indicating that thrombin signals ischemic damage via PAR-1. The c-Jun N-terminal kinase (JNK) pathway plays an important role in excitotoxicity and cerebral ischemia and we observed activation of the JNK substrate, c-Jun in our model. Both the FXa inhibitor, fondaparinux and the PAR-1 antagonist SCH79797, decreased the level of phospho-c-Jun Ser73. These results indicate that FXa activates thrombin in cerebral ischemia, which leads via PAR-1 to the activation of the JNK pathway resulting in neuronal death.