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Heat shock protein 90 and tyrosine kinase regulate eNOS NO* generation but not NO* bioactivity. Am J Physiol Heart Circ Physiol 2004 Feb;286(2):H561-9



Pubmed ID




Scopus ID

2-s2.0-0942287342   49 Citations


An increase in the association of heat shock protein 90 (HSP90) with endothelial nitric oxide (NO) synthase (eNOS) is well recognized for increasing NO (NO*) production. Despite the progress in this field, the mechanisms by which HSP90 modulates eNOS remain unclear due, in part, to the fact that geldanamycin (GA) redox cycles to generate superoxide anion (O(2)(-*) and the fact that inhibiting HSP90 with GA or radicicol (RAD) destabilizes tyrosine kinases that rely on the chaperone for maturation. In this report, we determine the extent to which these side effects alter vascular and endothelial cell function in physiologically relevant systems and in cultured endothelial cells. Vascular endothelial growth factor (VEGF)-stimulated vascular permeability, as measured by Evans blue leakage in the ears of male Swiss mice in vivo, and acetylcholine-induced vasodilation of isolated, pressurized mandibular arterioles from male C57BL6 mice ex vivo were attenuated by N(omega)-nitro-L-arginine methyl ester (L-NAME), GA, and RAD. Z-1[N-(2-aminoethyl)-N-(2-ammonoethyl)amino]diazen-1-ium-1,2-dioate (DETA-NONOate), a slow releasing NO. donor, increased vasodilation of arterioles pretreated with GA, RAD, and L-NAME equally well except at 10(-5) M, the highest concentration used, where vasodilation was greater in pressurized arterioles treated with L-NAME than in arterioles pretreated with GA or RAD alone. Both GA and RAD reduced NO* release from stimulated endothelial cell cultures and increased O(2)(-*) production in the endothelium of isolated aortas by an L-NAME-inhibitable mechanism. Pretreatment with RAD increased stimulated O(2)(-*) production from eNOS, whereas pretreatment with genistein (GE), a broad-spectrum tyrosine kinase inhibitor, did not; however, pretreatment with GE + RAD resulted in a super-induced state of uncoupled eNOS activity upon stimulation. These data suggest that the tyrosine kinases, either directly or indirectly, and HSP90-dependent signaling pathways act in concert to suppress uncoupled eNOS activity.

Author List

Ou J, Fontana JT, Ou Z, Jones DW, Ackerman AW, Oldham KT, Yu J, Sessa WC, Pritchard KA Jr


Keith T. Oldham MD Professor in the Surgery department at Medical College of Wisconsin
Kirkwood A. Pritchard PhD Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Capillary Permeability
Carotid Arteries
Endothelium, Vascular
Enzyme Inhibitors
HSP90 Heat-Shock Proteins
In Vitro Techniques
Mice, Inbred C57BL
Muscle, Smooth, Vascular
NG-Nitroarginine Methyl Ester
Nitric Oxide
Nitric Oxide Synthase
Nitric Oxide Synthase Type II
Nitric Oxide Synthase Type III
Protein-Tyrosine Kinases
Vascular Endothelial Growth Factor A
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a