Oxidative stress affects the integrin-linked kinase signaling pathway after transient focal cerebral ischemia.
OBJECTIVE
The integrin-linked kinase (ILK) signaling pathway contributes to regulation of cellular adhesion, migration, and differentiation, and to apoptotic cell death after a variety of cell death stimuli. We have reported that overexpression of copper/zinc superoxide dismutase (SOD1) reduces apoptotic cell death by promoting the phosphatidylinositol 3-kinase (PI3-K)/Akt survival pathway after transient focal cerebral ischemia (tFCI). However, the role of the ILK pathway after tFCI and the role of oxygen free radicals in regulation of apoptosis remain unclear.


METHODS
To clarify these issues, we used an in vivo tFCI model with SOD1 transgenic mice and wild-type mice. We administered the PI3-K inhibitor, LY294002, into mouse brains after tFCI and examined the role of PI3-K in the ILK pathway and expression of the ILK/Akt complex by immunohistochemistry, Western blot analysis, and coimmunoprecipitation.


RESULTS
A transient increase in ILK was detected early after tFCI and was prevented by treatment with LY294002, but promoted by SOD1. Coimmunoprecipitation revealed that the direct reaction of ILK/Akt transiently increased concurrent with the increase in ILK after tFCI. Moreover, the ILK/Akt complex was prevented by LY294002, but promoted by SOD1.


CONCLUSIONS
These results suggest that the ILK pathway mediated by PI3-K is affected by tFCI and by SOD1.
Department of Neurosurgery, Stanford University School of Medicine, Stanford, Calif 94305-5487, USA.
Atsushi
A
Saito
Takeshi
T
Hayashi
Shuzo
S
Okuno
Tatsuro
T
Nishi
Pak H
PH
Chan
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D002867:Chromones / Q000008:administration & dosage / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009025:Morpholines / Q000008:administration & dosage / Q000494:pharmacology; D018384:Oxidative Stress; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D000072105:Superoxide Dismutase-1; D000099200:Scaffold Protein ILK
D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D000099200:Scaffold Protein ILK; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C000606291:Sod1 protein, mouse