There is a fundamental gap in our understanding of the mechanisms of the release of mitochondrial apoptogenic factors induced by elevated Ca2+ and by pro-apoptotic proteins. Our long-term goal is to establish the role of mitochondria in neuronal apoptosis. The objective of this study is to delineate the mechanisms of release of apoptogenic proteins from brain mitochondria initiated by elevated Ca2+ or by pro-apoptotic proteins. The central hypothesis of the proposed research is that an increased generation of reactive oxygen species, augmentation of lipid peroxidation, activation of phospholipase A2, and K+ influx in brain mitochondria are the major processes leading to the release of apoptogenic proteins induced by elevated Ca2+ or pro-apoptotic proteins tBID and BAX.
In Specific Aim 1 we will establish K+-dependent mechanisms of the Ca2+-induced swelling of brain mitochondria and release of apoptogenic proteins. Inhibitors of mitochondrial K+ channels and the adenine nucleotide translocase will be applied to isolated brain mitochondria or to cultured neurons to establish their role in the Ca2+-induced swelling, and release of apoptogenic proteins.
In Specific Aim 2 we will determine the extent to which an activation of mitochondrial K+ channels and the permeability transition contributes to the release of apoptogenic factors induced by pro-apoptotic proteins tBID and BAX. Inhibitors of the permeability transition and blockers of K+ channels will be used to identify their role in the release of the apoptogenic proteins.
In Specific Aim 3 we will establish the role of reactive oxygen species, lipid peroxidation and phospholipase A2 in the release of apoptogenic proteins induced by tBID and BAX. Various antioxidants and inhibitors of phospholipase A2 will be used to inhibit the release of apoptogenic proteins.
In Specific Aim 4 we will determine the role of caspases in the release of apoptogenic proteins from brain mitochondria exposed to tBID and BAX. Isolated brain mitochondria exposed to tBID and BAX and treated with recombinant caspases will be used to test this hypothesis. The proposed research lays the foundation for a better understanding of the molecular mechanisms of the permeabilization of the outer mitochondrial membrane induced by elevated Ca 2+ or pro-apoptotic proteins tBID and BAX and contributes to filling in a gap in our knowledge of these phenomena.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS050131-04
Application #
7340745
Study Section
Neurodegeneration and Biology of Glia Study Section (NDBG)
Program Officer
Golanov, Eugene V
Project Start
2004-12-01
Project End
2009-11-30
Budget Start
2007-12-01
Budget End
2008-11-30
Support Year
4
Fiscal Year
2008
Total Cost
$259,428
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Pharmacology
Type
Schools of Medicine
DUNS #
603007902
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Brittain, Matthew K; Brustovetsky, Tatiana; Brittain, Joel M et al. (2012) Ifenprodil, a NR2B-selective antagonist of NMDA receptor, inhibits reverse Na+/Ca2+ exchanger in neurons. Neuropharmacology 63:974-82
Brittain, Matthew K; Brustovetsky, Tatiana; Sheets, Patrick L et al. (2012) Delayed calcium dysregulation in neurons requires both the NMDA receptor and the reverse Na+/Ca2+ exchanger. Neurobiol Dis 46:109-17
Ashpole, Nicole M; Song, Weihua; Brustovetsky, Tatiana et al. (2012) Calcium/calmodulin-dependent protein kinase II (CaMKII) inhibition induces neurotoxicity via dysregulation of glutamate/calcium signaling and hyperexcitability. J Biol Chem 287:8495-506
Kumar, Sanjay; Chakraborty, Saikat; Barbosa, Cindy et al. (2012) Mechanisms controlling neurite outgrowth in a pheochromocytoma cell line: the role of TRPC channels. J Cell Physiol 227:1408-19
Brittain, Joel M; Chen, Liang; Wilson, Sarah M et al. (2011) Neuroprotection against traumatic brain injury by a peptide derived from the collapsin response mediator protein 2 (CRMP2). J Biol Chem 286:37778-92
Brittain, Joel M; Duarte, Djane B; Wilson, Sarah M et al. (2011) Suppression of inflammatory and neuropathic pain by uncoupling CRMP-2 from the presynaptic Ca²? channel complex. Nat Med 17:822-9
Brustovetsky, Tatiana; Brittain, Matthew K; Sheets, Patrick L et al. (2011) KB-R7943, an inhibitor of the reverse Na+ /Ca2+ exchanger, blocks N-methyl-D-aspartate receptor and inhibits mitochondrial complex I. Br J Pharmacol 162:255-70
Brustovetsky, Tatiana; Li, Tsyregma; Yang, Youyun et al. (2010) BAX insertion, oligomerization, and outer membrane permeabilization in brain mitochondria: role of permeability transition and SH-redox regulation. Biochim Biophys Acta 1797:1795-806
Brustovetsky, Tatiana; Bolshakov, Alexey; Brustovetsky, Nickolay (2010) Calpain activation and Na+/Ca2+ exchanger degradation occur downstream of calcium deregulation in hippocampal neurons exposed to excitotoxic glutamate. J Neurosci Res 88:1317-28
Storozhevykh, T P; Senilova, Ya E; Brustovetsky, T et al. (2010) Neuroprotective effect of KB-R7943 against glutamate excitotoxicity is related to mild mitochondrial depolarization. Neurochem Res 35:323-35

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