Toward safer thrombolytic agents in stroke: molecular requirements for NMDA receptor-mediated neurotoxicity

• Published in: Journal of cerebral blood flow and metabolism Vol. 28; no. 6; pp. 1212 - 1221
• Main Authors: Lopez-Atalaya, Jose P, Roussel, Benoit D, Levrat, Denis, Parcq, Jérôme, Nicole, Olivier, Hommet, Yannick, Benchenane, Karim, Castel, Hervé, Leprince, Jérôme, To Van, Denis, Bureau, Ronan, Rault, Sylvain, Vaudry, Hubert, Petersen, Karl-Uwe, Santos, Jana Sopkova-de Oliveira, Ali, Carine, Vivien, Denis
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.06.2008; Lippincott Williams & Wilkins; Sage Publications Ltd; Nature Publishing Group
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Blood. Blood coagulation. Reticuloendothelial system; Catalytic Domain; Cell Behavior; Cells, Cultured; Cellular Biology; Chemical Sciences; Drug-Related Side Effects and Adverse Reactions; Fibrinolytic Agents; Fibrinolytic Agents - toxicity; Life Sciences; Medical sciences; Medicinal Chemistry; Mice; Models, Molecular; Molecular Sequence Data; Neurobiology; Neurology; Neurons; Neurons - drug effects; Neurons - metabolism; Neurons and Cognition; Pharmaceutical sciences; Pharmacology; Pharmacology. Drug treatments; Plasminogen Activators; Plasminogen Activators - metabolism; Protein Binding; Protein Structure, Quaternary; Receptors, N-Methyl-D-Aspartate; Receptors, N-Methyl-D-Aspartate - chemistry; Receptors, N-Methyl-D-Aspartate - genetics; Receptors, N-Methyl-D-Aspartate - metabolism; Signal Transduction; Stroke; Stroke - metabolism; Tissue Culture Techniques; Tissue Plasminogen Activator; Tissue Plasminogen Activator - chemistry; Tissue Plasminogen Activator - metabolism; Vascular diseases and vascular malformations of the nervous system; thrombolysis; kringle; neurotoxicity; stroke; Vascular disease; Stroke; Nervous system diseases; Central nervous system disease; Cardiovascular disease; NMDA receptor; Cerebrovascular disease; Cerebral disorder
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1038/jcbfm.2008.14

Current thrombolytic therapy for acute ischemic stroke with tissue-type plasminogen activator (tPA) has clear global benefits. Nevertheless, evidences argue that in addition to its prohemorrhagic effect, tPA might enhance excitotoxic necrosis. In the brain parenchyma, tPA, by binding to and then cleaving the amino-terminal domain (ATD) of the NR1 subunit of N-methyl-d-aspartate (NMDA) glutamate receptors, increases calcium influx to toxic levels. We show here that tPA binds the ATD of the NR1 subunit by a two-sites system (KD=24 nmol/L). Although tenecteplase (TNK) and reteplase also display two-sites binding profiles, the catalytically inactive mutant TNKS478A displays a one-site binding profile and desmoteplase (DSPA), a kringle 2 (K2) domain-free plasminogen activator derived from vampire bat, does not interact with NR1. Moreover, we show that in contrast to tPA, DSPA does not promote excitotoxicity. These findings, together with three-dimensional (3D) modeling, show that a critical step for interaction of tPA with NR1 is the binding of its K2 domain, followed by the binding of its catalytic domain, which in turn cleaves the NR1 subunit at its ATD, leading to a subsequent potentiation of NMDA-induced calcium influx and neurotoxicity. This could help design safer new generation thrombolytic agents for stroke treatment.