Elevated expression of molecular chaperones has been shown to suppress protein misfolding/aggregation and toxicity in various model systems of Huntington's disease, Alzheimer's disease, Parkinson's disease, and Amyotrophic Lateral Sclerosis (ALS). Mutations in the respective proteins associated with these diseases results in the appearance of misfolded species that adopt alternate conformations. These observations have led to the proposal that a common feature of mutant huntingtin, tau, alpha-synuclein, and superoxide dismutase (SOD1) is the appearance of alternate folded states that self-associate and form toxic species and protein aggregates. Molecular chaperones offer intriguing targets for therapeutics because of their unique characteristic to recognize and sequester damaged and misfolded species. Consequently, chaperones may have a central role in protein homeostasis to prevent the deleterious consequences of chronic misfolded species, that, over time results in cell dysgenesis and pathologies as occurs in neurodegenerative diseases and other diseases associated with protein misfolding. However, because chaperones function in vivo as networks, it has also become increasingly evident that the expression of individual chaperones alone is either ineffective or much less effective than the coordinated expression of multiple chaperones to achieve maximal network functionality. We propose three Specific Aims:
Aim 1. To establish a robust primary screen for small molecule regulators of the heat shock response;
Aim 2. To characterize the candidates for cytotoxicity and kinetics of induction of HS gene expression and chaperone levels;
and Aim 3. To test small molecule regulators of the heat shock response in secondary assays of cells expressing mutant huntingtin and SOD1. Although our experiments will only examine the consequences of novel small molecule regulators of chaperone expression on model systems of neurodegenerative disease, we anticipate that our results may well extend to other pathologies associated with the flux of misfolded proteins in the cytoplasm. ? ? ?
