For over a decade, ALS-associated SOD1 mutants have been compared to wild-type enzyme, both in vitro and in vivo in an attempt to understand the mechanism(s) of pathogenesis. However, little is known about the molecular mechanisms which underlie pharmacologically-mediated extension of survival in G93A mice. We have identified two chemically distinct (organomanganic) compounds which markedly extend survival in G93A mice when given at disease onset (similar to when human treatment would begin). Based on our results, efforts are underway to conduct human clinical trials in ALS with these compounds. We propose to use these highly efficacious compounds to probe the mechanisms of protection, while continuing our work on the mechanisms of SOD1 mutant-mediated toxicity. We will examine protein expression changes which accompany protection by these compounds and the ultimate loss of protection (Aim 1) in order to gain a better understanding of the mechanisms involved. The magnitude of life extension with these compounds rivals the best yet reported for any compound, even those administered presymptomatically. However, reliable comparisons require comparable treatment regimens. We propose to test compounds that show efficacy when given presymptomatically in an onset administration paradigm (Aim 2) to test the hypothesis that the failure of some human trials may relate to differences in study design. Compelling new evidence suggests that mitochondrial uptake of mutants is critical to disease and that uptake is determined by metallation state (primarily zinc) and the status of an internal disulfide. Herein we offer fundamentally new evidence that a zinc-deficient mutant in vivo directly correlates with disease severity, and that mutant SOD1 (but not wild-type) is covalently cross linked.
Aim 3 will identify the cross linked proteins and determine if drug treatment alters it.
Aim 4 will extend our studies of in vivo metallation states and thiol status of mutants using enzyme purified from spinal cord as an """"""""in vivo expression system"""""""". ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS040819-05A2
Application #
7260026
Study Section
Cell Death in Neurodegeneration Study Section (CDIN)
Program Officer
Refolo, Lorenzo
Project Start
2000-12-01
Project End
2012-04-30
Budget Start
2007-05-15
Budget End
2008-04-30
Support Year
5
Fiscal Year
2007
Total Cost
$381,098
Indirect Cost
Name
University of Arkansas for Medical Sciences
Department
Pharmacology
Type
Schools of Medicine
DUNS #
122452563
City
Little Rock
State
AR
Country
United States
Zip Code
72205
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