Neurological diseases disrupt the quality of the lives of patients, puts a tremendous burden on family caregivers, and cost society billions of dollars annually. A common feature of neurological diseases is the degeneration of neurons by apoptosis. Drugs that inhibit neuronal apoptosis could thus be candidates for therapeutic intervention in neurodegenerative disorders. Moreover, identifying the molecular targets of such neuroprotective drugs and understanding the signal transduction pathways that are utilized in their action would lead to the development of more effective therapeutic strategies. Working with a cell culture paradigm of neuronal apoptosis that uses rat cerebellar granule neurons we have identified a drug, GW5074 {5-Iodo-3-[(3,5-dibromo-4-hydroxyphenyl)methylene]-2-indolinone} that completely inhibits neuronal apoptosis. GW5074 is a specific and potent inhibitor of c-Raf when tested in vitro. Paradoxically, however, treatment of cultured neurons with GW5074 leads to the accumulation of activating modifications on c-Raf. Moreover, GW5074 treatment stimulates B-Raf activity. Among the molecules affected downstream of c-Raf in neurons treated with GW5074 are the antiapoptotic molecule NF-kappa b. GW5074 also inhibits the proapoptotic transcription factor, c-jun. Although GW5074 is the most effective, neuroprotection is also observed by two other chemical inhibitors of c-Raf. The utility of small molecule inhibitors of c-Raf as neuroprotective agents has not been described previously. The overall goal of this proposal is to use GW5074 to understand the molecular mechanism by which inhibitors of c-Raf exert their antiapoptotic effect and to more thoroughly investigate the potential of GW5074 as a neurotherapeutic agent. Our specific goals are to: (1) better understand the effect of GW5074 on c-Raf and B-Raf understand the effect of GW5074 on c-Raf, (2) analyze the downstream mechanisms by which GW5074 exerts its neuroprotective effect, and (3) examine whether the molecular effects of GW5074 in cultured cerebellar granule neurons are also observed in an animal model of neurodegeneration. It is our hope that GW5074 (or other c-Raf inhibitors like it) will emerge as a highly effective and versatile therapeutic agent that could proceed towards clinical trials for the treatment of neurological diseases in the near future.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS047201-01A1
Application #
6820210
Study Section
Neurodegeneration and Biology of Glia Study Section (NDBG)
Program Officer
Nunn, Michael
Project Start
2004-07-01
Project End
2009-02-28
Budget Start
2004-07-01
Budget End
2005-02-28
Support Year
1
Fiscal Year
2004
Total Cost
$311,147
Indirect Cost
Name
University of Texas-Dallas
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
800188161
City
Richardson
State
TX
Country
United States
Zip Code
75080
Ma, Chi; D'Mello, Santosh R (2011) Neuroprotection by histone deacetylase-7 (HDAC7) occurs by inhibition of c-jun expression through a deacetylase-independent mechanism. J Biol Chem 286:4819-28
Chen, Huai-Lu; D'Mello, Santosh R (2010) Induction of neuronal cell death by paraneoplastic Ma1 antigen. J Neurosci Res 88:3508-19
Zhao, Kelly; Ippolito, Giulia; Wang, Lulu et al. (2010) Neuron-selective toxicity of tau peptide in a cell culture model of neurodegenerative tauopathy: essential role for aggregation in neurotoxicity. J Neurosci Res 88:3399-413
Majdzadeh, Nazanin; Morrison, Brad E; D'Mello, Santosh R (2008) Class IIA HDACs in the regulation of neurodegeneration. Front Biosci 13:1072-82
Chen, Hsin-Mei; Wang, Lulu; D'Mello, Santosh R (2008) A chemical compound commonly used to inhibit PKR, {8-(imidazol-4-ylmethylene)-6H-azolidino[5,4-g] benzothiazol-7-one}, protects neurons by inhibiting cyclin-dependent kinase. Eur J Neurosci 28:2003-16
Balderamos, Michael; Ankati, Haribabu; Akubathini, Shashidhar Kumar et al. (2008) Synthesis and structure-activity relationship studies of 3-substituted indolin-2-ones as effective neuroprotective agents. Exp Biol Med (Maywood) 233:1395-402
Chen, Hsin-Mei; Wang, Lulu; D'Mello, Santosh R (2008) Inhibition of ATF-3 expression by B-Raf mediates the neuroprotective action of GW5074. J Neurochem 105:1300-12
Morrison, Brad E; Majdzadeh, Nazanin; Zhang, Xiaoguang et al. (2006) Neuroprotection by histone deacetylase-related protein. Mol Cell Biol 26:3550-64
D'Mello, Santosh R; Chin, Paul C (2005) Treating neurodegenerative conditions through the understanding of neuronal apoptosis. Curr Drug Targets CNS Neurol Disord 4:3-23
Johnson, Kyle; Liu, Li; Majdzadeh, Nazanin et al. (2005) Inhibition of neuronal apoptosis by the cyclin-dependent kinase inhibitor GW8510: identification of 3' substituted indolones as a scaffold for the development of neuroprotective drugs. J Neurochem 93:538-48