title: Rac1 is a critical mediator of endothelium-derived neurotrophic activity.
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.
authors.affiliation: Vascular Medicine Research, Brigham and Women's Hospital, Cambridge, MA 02139, USA.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sawada
authors.forename: Hyung-Hwan
authors.initials: HH
authors.lastname: Kim
authors.forename: Michael A
authors.initials: MA
authors.lastname: Moskowitz
authors.forename: James K
authors.initials: JK
authors.lastname: Liao
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D042783:Endothelial Cells / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000235:genetics*; D051379:Mice; D008817:Mice, Mutant Strains; D046228:Microarray Analysis; D009414:Nerve Growth Factors / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein
chemical_list: D017304:Annexin A5; C116599:Artn protein, mouse; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; C484602:Rac1 protein, mouse; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein