In this project we will define a role for copper-zinc superoxide dismutase (SOD1) in the regulation of cell survival and death. While the wild-type (WT) SOD1 is a pro-survival protein, amyotrophic lateral sclerosis (ALS)-linked SOD1 mutants are toxic both in vitro and in vivo. We recently found that both WT and mutant SOD1 interact with the anti-apoptotic protein Bcl-2. However, the nature of the mutant SOD1 binding with Bcl-2 differs from WT SOD1. Contrary to WT SOD1, mutant SOD1 specifically localizes to spinal cord mitochondria where it forms SDS-resistant high molecular weight aggregates that bind and entrap Bcl-2. (Pasinelli et al, 2004, Neuron 43: 19-30). These studies suggest a potentially novel function for WT SOD1 in regulating cell survival and death, and a novel, toxic gain-of-function for mutant SOD1. Thus, while WT SOD1 may protect against cell death through its interaction with Bcl-2, mutant SOD1 may become toxic by aberrantly binding to Bcl-2 and converting Bcl-2 into a toxic or non-functional protein. In support of this hypothesis, we now have preliminary data indicating that both WT and mutant SOD1 might require Bcl-2 to exert their anti-and-pro apoptotic function respectively. With the present proposal we intend to characterize the anti and pro-death function of WT and mutant SOD1 and their respective interactions with Bcl-2. The ultimate goal is to understand the mechanism(s) of mutant SOD1-mediated toxicity and to define a potential role for the mitochondrial mutant SOD1/Bcl-2 complex in ALS pathogenesis.
The specific aims are: 1) (A) To determine whether WT SOD1 pro-survival activity depends on its binding to Bcl-2, and (B) to determine whether mutant SOD 1-mediated toxicity depends on the aberrant interaction with Bcl-2. 2) (A) To identify the region(s) in SOD1 essential for the binding with Bcl-2, and (B) to study the difference in binding strength between WT SOD1 and Bcl-2 and mutant SOD1 and Bcl-2. 3) (A) To determine whether Bcl-2 undergoes conformational modifications upon binding with mutant SOD1 and.(B) to test the potential benefit of Bcl-2 and SOD1 like-peptides that abolish binding between Bcl-2 and mutant SOD1 on our cell culture model of mutant SOD1-linked ALS. 4) To determine whether Bcl-2 mediates mutant SOD1 mitochondrial translocation. 5) To study the correlation between mutant SOD1/Bcl-2-containing aggregates and ALS using transgenic ALS mice and patients.
|Kia, Azadeh; McAvoy, Kevin; Krishnamurthy, Karthik et al. (2018) Astrocytes expressing ALS-linked mutant FUS induce motor neuron death through release of tumor necrosis factor-alpha. Glia 66:1016-1033|
|Jablonski, Michael; Miller, David S; Pasinelli, Piera et al. (2015) ABC transporter-driven pharmacoresistance in Amyotrophic Lateral Sclerosis. Brain Res 1607:1-14|
|Wen, Xinmei; Tan, Wenzhi; Westergard, Thomas et al. (2014) Antisense proline-arginine RAN dipeptides linked to C9ORF72-ALS/FTD form toxic nuclear aggregates that initiate in vitro and in vivo neuronal death. Neuron 84:1213-25|
|Tan, Wenzhi; Pasinelli, Piera; Trotti, Davide (2014) Role of mitochondria in mutant SOD1 linked amyotrophic lateral sclerosis. Biochim Biophys Acta 1842:1295-301|
|Tan, Wenzhi; Naniche, Nicole; Bogush, Alexey et al. (2013) Small peptides against the mutant SOD1/Bcl-2 toxic mitochondrial complex restore mitochondrial function and cell viability in mutant SOD1-mediated ALS. J Neurosci 33:11588-98|
|Bowling, C Barrett; Booth 3rd, John N; Safford, Monika M et al. (2013) Nondisease-specific problems and all-cause mortality in the REasons for Geographic and Racial Differences in Stroke study. J Am Geriatr Soc 61:739-46|
|Jablonski, Michael R; Jacob, Dena A; Campos, Christopher et al. (2012) Selective increase of two ABC drug efflux transporters at the blood-spinal cord barrier suggests induced pharmacoresistance in ALS. Neurobiol Dis 47:194-200|
|Guareschi, Stefania; Cova, Emanuela; Cereda, Cristina et al. (2012) An over-oxidized form of superoxide dismutase found in sporadic amyotrophic lateral sclerosis with bulbar onset shares a toxic mechanism with mutant SOD1. Proc Natl Acad Sci U S A 109:5074-9|
|Naniche, Nicole; Sau, Daniela; Pasinelli, Piera (2011) In vivo and in vitro determination of cell death markers in neurons. Methods Mol Biol 793:9-21|
|Foran, Emily; Bogush, Alexey; Goffredo, Michael et al. (2011) Motor neuron impairment mediated by a sumoylated fragment of the glial glutamate transporter EAAT2. Glia 59:1719-31|
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