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Sci. Signal., 10 March 2009
Vol. 2, Issue 61, p. ra10
[DOI: 10.1126/scisignal.2000162]


Rac1 Is a Critical Mediator of Endothelium-Derived Neurotrophic Activity

Naoki Sawada1, Hyung-Hwan Kim1, Michael A. Moskowitz2, and James K. Liao1*

1 Vascular Medicine Research, Brigham and Women’s Hospital, 65 Landsdowne Street, Room 275, Cambridge, MA 02139, USA.
2 Stroke and Neurovascular Regulation Laboratory, Massachusetts General Hospital, Charlestown, MA 02129, USA.

Abstract: The therapeutic potential of neurotrophic factors has been hampered by their inability to achieve adequate tissue penetration. Brain blood vessels, however, could be an alternative target for neurosalvage therapies by virtue of their close proximity to neurons. Here we show that hemizygous deletion of Rac1 in mouse endothelial cells (ECs) attenuates brain injury and edema after focal cerebral ischemia. Microarray analysis of Rac1+/– ECs revealed enrichment of stress response genes, basement membrane components, and neurotrophic factors that could affect neuronal survival. Consistent with these expression profiles, endothelial Rac1 hemizygosity enhanced antioxidative and endothelial barrier capacities and potentiated paracrine neuroprotective activities through the up-regulation of the neurotrophic factor, artemin. Endothelial Rac1, therefore, could be an important therapeutic target for promoting endothelial barrier integrity and neurotrophic activity.

* To whom correspondence should be addressed. E-mail: jliao{at}

Citation: N. Sawada, H.-H. Kim, M. A. Moskowitz, J. K. Liao, Rac1 Is a Critical Mediator of Endothelium-Derived Neurotrophic Activity. Sci. Signal. 2, ra10 (2009).

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