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Tissue plasminogen activator neurovascular toxicity is controlled by activated protein C


Although thrombolytic effects of tissue plasminogen activator (tPA) are beneficial, its neurotoxicity1,2,3,4,5 is problematic. Here, we report that tPA potentiates apoptosis in ischemic human brain endothelium and in mouse cortical neurons treated with N-methyl-D-aspartate (NMDA) by shifting the apoptotic pathways from caspase-9 to caspase-8, which directly activates caspase-3 without amplification through the Bid-mediated mitochondrial pathway6. In vivo, tPA-induced cerebral ischemic injury in mice was reduced by intracerebroventricular administration of caspase-8 inhibitor, but not by caspase-9 inhibitor, in contrast to controls in which caspase-9 inhibitor, but not caspase-8 inhibitor, was protective. Activated protein C (APC), a serine protease with anticoagulant, anti-inflammatory and antiapoptotic activities7, which is neuroprotective during transient ischemia8,9 and promotes activation of antiapoptotic mechanisms in brain cells by acting directly on endothelium9,10,11 and neurons12, blocked tPA vascular and neuronal toxicities in vitro and in vivo. APC inhibited tPA-induced caspase-8 activation of caspase-3 in endothelium and caspase-3–dependent nuclear translocation of apoptosis-inducing factor in NMDA-treated neurons and reduced tPA-mediated cerebral ischemic injury in mice. Data suggest that tPA shifts the apoptotic signal in stressed brain cells from the intrinsic to the extrinsic pathway which requires caspase-8. APC blocks tPA's neurovascular toxicity and may add substantially to the effectiveness of tPA therapy for stroke.

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Figure 1: tPA toxicity to human BEC and cytoprotection by human APC.
Figure 2: tPA's apoptotic signal in hypoxic human BEC requires caspase-8 and is blocked by APC.
Figure 3: tPA shifts NMDA-induced apoptosis in mouse cortical neurons to caspase-8 which is blocked by mouse APC.
Figure 4: tPA-induced cerebral injury in a mouse stroke model and protection by mouse APC.


  1. Wang, Y.F. et al. Tissue plasminogen activator (tPA) increases neuronal damage after focal cerebral ischemia in wild-type and tPA-deficient mice. Nat. Med. 4, 228–231 (1998).

    CAS  Article  Google Scholar 

  2. Nicole, O. et al. The proteolytic activity of tissue-plasminogen activator enhances NMDA receptor-mediated signaling. Nat. Med. 7, 59–64 (2001).

    CAS  Article  Google Scholar 

  3. Yepes, M. et al. Regulation of seizure spreading by neuroserpin and tissue-type plasminogen activator is plasminogen-independent. J. Clin. Invest. 109, 1571–1578 (2002).

    CAS  Article  Google Scholar 

  4. Matys, T. & Strickland, S. Tissue plasminogen activator and NMDA receptor cleavage. Nat. Med. 9, 371–373 (2003).

    CAS  Article  Google Scholar 

  5. Chen, Z.L. & Strickland, S. Neuronal death in the hippocampus is promoted by plasmin-catalyzed degradation of laminin. Cell 91, 917–925 (1997).

    CAS  Article  Google Scholar 

  6. Plesnila, N., et al. BID mediates neuronal cell death after oxygen/glucose deprivation and focal cerebral ischemia. Proc. Natl. Acad. Sci. USA 98, 15318–15323 (2001).

    CAS  Article  Google Scholar 

  7. Griffin, J.H. et al. Activated protein C and ischemic stroke. Crit. Care Med. 32, S247–S253 (2004).

    CAS  Article  Google Scholar 

  8. Shibata, M. et al. Anti-inflammatory, antithrombotic, and neuroprotective effects of activated protein C in a murine model of focal ischemic stroke. Circulation 103, 1799–1805 (2001).

    CAS  Article  Google Scholar 

  9. Cheng, T. et al. Activated protein C blocks p53-mediated apoptosis in ischemic human brain endothelium and is neuroprotective. Nat. Med. 9, 338–342 (2003).

    CAS  Article  Google Scholar 

  10. Joyce, D.E., Gelbert, L., Ciaccia, A., DeHoff, B. & Grinnell, B.W. Gene expression profile of antithrombotic protein C defines new mechanisms modulating inflammation and apoptosis. J. Biol. Chem. 276, 11199–11203 (2001).

    CAS  Article  Google Scholar 

  11. Riewald, M., Petrovan, R.J., Donner, A., Mueller, B.M. & Ruf, W. Activation of endothelial cell protease activated receptor 1 by the protein C pathway. Science 296, 1880–1882 (2002).

    CAS  Article  Google Scholar 

  12. Guo, H. et al. Activated protein C prevents neuronal apoptosis via protease activated receptors 1 and 3. Neuron 42, 563–572 (2004).

    Article  Google Scholar 

  13. Lo, E.H., Broderick, J.P. & Moskowitz, M.A. tPA and proteolysis in the neurovascular unit. Stroke 35, 354–356 (2004).

    Article  Google Scholar 

  14. Sharp, C.D., et al. Glutamate causes a loss in human cerebral endothelial barrier integrity through activation of NMDA receptor. Am. Physiol. Heart Circ. Physiol. 285, H2592–H2598 (2003).

    CAS  Article  Google Scholar 

  15. Budd, S.L., Tenneti, L., Lishnak, T. & Lipton, S.A. Mitochondrial and extramitochondrial apoptotic signaling pathways in cerebrocortical neurons. Proc. Natl. Acad. Sci. USA 97, 6161–6166 (2000).

    CAS  Article  Google Scholar 

  16. Stennicke, H.R., et al. Pro-caspase-3 is a major physiologic target of caspase-8. J. Biol. Chem. 273, 27084–90 (1998).

    CAS  Article  Google Scholar 

  17. Zhang, W., et al. Fundamental role of the Rip2/caspase-1 pathway in hypoxia and ischemia-induced neuronal cell death. Proc. Natl. Acad. Sci. USA 100, 16012–16017 (2003).

    CAS  Article  Google Scholar 

  18. Du, Y.S., et al. Activation of a caspase 3-related cysteine protease is required for glutamate-mediated apoptosis of cultured cerebellar granule neurons. Proc. Natl. Acad. Sci. USA 94, 11657–11662 (1997).

    CAS  Article  Google Scholar 

  19. Okamoto, S., et al. Dominant – interfering forms of MEF2 generated by caspase cleavage contribute to NMDA-induced neuronal apoptosis. Proc. Natl. Acad. Sci. USA 99, 3974–3979 (2002).

    CAS  Article  Google Scholar 

  20. Penninger, J.M. and Kroemer, G. Mitochondria, AIF and caspases–rivaling for cell death execution. Nat. Cell Biol. 5, 97–99 (2003).

    CAS  Article  Google Scholar 

  21. Yu, S., et al. Mediation of poly (APD-Ribose) polymerase-1-dependent cell death by apoptosis-inducing factor. Science 297, 259–263 (2002).

    CAS  Article  Google Scholar 

  22. Tabrizi, P. et al. Tissue plasminogen activator (tPA) deficiency exacerbates cerebrovascular fibrin deposition and brain injury in murine stroke model: studies in tPA-deficient mice and wild-type mice on a matched genetic background. Arterioscler. Thromb. Vasc. Biol. 19, 2801–2806 (1999).

    CAS  Article  Google Scholar 

  23. Jiang, Q. et al. Magnetic resonance imaging indexes of therapeutic efficacy of recombinant tissue plasminogen activator treatment of rat at 1 and 4 hours after embolic stroke. J. Cereb. Blood Flow Metab. 20, 21–27 (2000).

    CAS  Article  Google Scholar 

  24. Pichiule, P. & LaManna, J.C. Angiopoietin-2 and rat brain capillary remodeling during adaptation and deadaptation to prolonged mild hypoxia. J. Appl. Physiol. 93, 1131–1139 (2002).

    CAS  Article  Google Scholar 

  25. Tibbetts, M.D., Zheng, L. & Lenardo, M.J. The death effector domain protein family: regulators of cellular homeostasis. Nat. Immunol. 4, 404–409 (2003).

    CAS  Article  Google Scholar 

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This work was supported by the United States National Institutes of Health grant HL63290.

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Correspondence to Berislav V Zlokovic.

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Berislav V. Zlokovic serves as a consultant for Socratech LLC, which potentially may have interest in developing activated protein C.

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Liu, D., Cheng, T., Guo, H. et al. Tissue plasminogen activator neurovascular toxicity is controlled by activated protein C. Nat Med 10, 1379–1383 (2004).

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