The long-term goal of this research is, through the use of cellular and animal models of cerebral ischemia, to explore novel molecular targets for therapeutic interventions in stroke. Ischemic brain injury may involve an active type of cell death reminiscent of apoptosis, especially when the ischemic insult is relatively mild and cellular energy metabolism is not irreversibly compromised. Current studies have identified a group of terminal caspases, particularly caspase-3/-7, as the central executive molecules in apoptotic ischemic neuronal death. Upon activation, caspase-3 cleaves various death substrates in the cytosol and nucleus, leading to cell death. The precise mechanism by which caspase-3 is activated in ischemic neurons is poorly understood, however, it may involve both intrinsic (cytochrome c/Apaf-1 dependent) and extrinsic (cell membrane receptor mediated) pathways. Therefore, elucidation of these signaling pathways in ischemic injury may provide novel targets for therapeutic interventions to prevent caspase-3 activation and neuronal death after stroke. Under many experimental conditions, blockage of caspase activities is able to delay, but not prevent completely, neuronal death, suggesting that a caspase-independent death pathway must be involved. A novel pro-apoptotic molecule, designated as AIF (apoptosis-inducing factor), has now been identified. AIF, which is activated and released from the mitochondria upon receiving cell death signals, potently promotes nuclear apoptosis, independent of any caspase activities. Our preliminary studies strongly suggest that AIF may function independently and synergistically with caspase-3 in the final execution of neuronal ischemic apoptosis. Therefore, the overall hypothesis underlying this proposal is that ischemia-induced neuronal cell death is mediated by both caspase-dependent and caspase-independent mechanisms, particularly the AIF-dependent pathway. The two pathways work synergistically in mediating neuronal cell death. The scientific objective of this project is to elucidate the upstream pathways for the activation of caspase-3 and AIF and to determine whether targeting these apoptosis-signaling pathways can ameliorate brain injury after transient cerebral ischemia. We propose the following specific aims: 1) Test the hypothesis that the caspase-9/Apaf-1 intrinsic pathway plays a central role in mediating caspase-3 activation and neuronal death in the hippocampus after transient forebrain ischemia; 2) Test the hypothesis that AIF and caspase-3 contribute independently and synergistically to hippocampal neuronal death after transient forebrain ischemia; 3) Test the hypotheses that AIF mediates neuronal death in cell culture models of neuronal ischemia and that Bax triggers both AIF and caspase-9/Apaf-1 pathways in ischemic neuronal death. These studies will take advantage of our recent cloning of novel rat genes encoding the dominant-negative inhibitors for caspase-9, Apaf-1, and AIF. Molecular interventions targeting the speculative cell death pathways in ischemic neurons will be achieved using the state-of-the-art TAT-fusion protein transduction technology and AAV vector-mediated neuronal gene infection.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS045048-05
Application #
7175331
Study Section
Special Emphasis Panel (ZRG1-BDCN-1 (01))
Program Officer
Bosetti, Francesca
Project Start
2003-02-01
Project End
2009-01-31
Budget Start
2007-02-01
Budget End
2009-01-31
Support Year
5
Fiscal Year
2007
Total Cost
$267,116
Indirect Cost
Name
University of Pittsburgh
Department
Neurology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Ma, Shubei; Wang, Jianyi; Wang, Yanling et al. (2018) Diabetes Mellitus Impairs White Matter Repair and Long-Term Functional Deficits After Cerebral Ischemia. Stroke 49:2453-2463
Cai, Wei; Yang, Tuo; Liu, Huan et al. (2018) Peroxisome proliferator-activated receptor ? (PPAR?): A master gatekeeper in CNS injury and repair. Prog Neurobiol 163-164:27-58
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Zhang, Wenting; Chen, Ruiying; Yang, Tuo et al. (2018) Fatty acid transporting proteins: Roles in brain development, aging, and stroke. Prostaglandins Leukot Essent Fatty Acids 136:35-45
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Cai, Mengfei; Zhang, Wenting; Weng, Zhongfang et al. (2017) Promoting Neurovascular Recovery in Aged Mice after Ischemic Stroke - Prophylactic Effect of Omega-3 Polyunsaturated Fatty Acids. Aging Dis 8:531-545
Cai, Wei; Zhang, Kai; Li, Peiying et al. (2017) Dysfunction of the neurovascular unit in ischemic stroke and neurodegenerative diseases: An aging effect. Ageing Res Rev 34:77-87
Wu, Yun; Wang, Jiayin; Shi, Yejie et al. (2017) Implantation of Brain-Derived Extracellular Matrix Enhances Neurological Recovery after Traumatic Brain Injury. Cell Transplant 26:1224-1234
Hu, Xiaoming; De Silva, T Michael; Chen, Jun et al. (2017) Cerebral Vascular Disease and Neurovascular Injury in Ischemic Stroke. Circ Res 120:449-471

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