The long-term goals of this work include developing methods to image the stress response in the brains of experimental animals and humans, and to develop methods of manipulating the stress response in order to protect the brain against ischemia and other injuries. Experiments will determine whether local protein synthesis decreases in non-infarcted regions of cortex following focal ischemia in the rat and following global ischemia in the gerbil; and will determine whether the changes of protein synthesis correlate regionally and temporally with the induction of the HSP70 heat shock protein. It is proposed that the decreases in total protein synthesis could be used to indirectly image the stress response in non-infarcted human tissues. Studies of stress gene induction in ischemic human brain will be performed to show that the patterns of HSP70 and other stress gene induction are similar in human and rodent brain. The induction of the heme oxygenase-1 (HO-1) mRNA and protein will be examined in ischemic brains of normal mice, SOD transgenic and SOD knockout mice. Since HO-1 is induced by oxidative and ischemic stress, it is predicted that HO-1 will be induced to a greater degree in ischemic brains of SOD knockouts compared to SOD transgenics. Suppression of HO-1 induction with HO-1 antisense oligonucleotides is predicted to exacerbate ischemic injury more in SOD knockout compared to SOD transgenic mice. Since heme proteins induce the hemeosygenase HO-1 stress protein, it is proposed that prior treatment of animals with heme proteins will protect the brain against ischemic injury, Blockade of HO-1 induction may block protection produced by heme. Lastly, the cloning of the stress gene, methyl malonyl CoA mutase, will be completed and its induction following focal and global ischemia will be characterized, as well as the factors including lipid peroxidation that regulate its expression, Methods used will include rodent focal and global ischemia models, protein synthesis, cloning, DNA nick end-labeling, in situ hybridization and immunocytochemistry.
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