Three problems plague current methods of compound discovery. First, rational compound design can be used therapeutically to modify existing compounds if the compound target is known. However, for most diseases, there is little in depth understanding of the underlying biology. Second, compounds have also been selected based on their ability to inhibit or reverse specific disease-related phenotypes (e.g. protein proteolysis, aggregation). However, pre-selecting these phenotypes for compound development can be guesswork, as observable phenotypes do not often represent the primary defect or may be consequences of disease. Third, combinatorial library screens do not depend on knowing the compound target. However, these traditional screens are empirical in nature, and screening takes years, often without success. Even if a compound lead is identified in traditional screens, the actual compound target is typically not known. Therefore, increasing the potency and specificity of a lead in subsequent iterations can be a difficult and long-term process, and has not historically been successful. In this proposal, we develop, test and apply a new """"""""intelligent"""""""" methodology that allows discovery in a systematic and directed manner. The method is called fingerprinting. The method is general and can apply to any disease gene, but in this proposal, we apply the methodology to Huntington's Disease. Disease-expressing cells are incubated with 20,000 siRNAs to knock-down all mammalian genes. Knocked down genes fall into two classes. Those that have no effect on toxicity and those genes whose loss enhance survival of mhtt-expressing cells. The set of genes whose loss enhances cell survival is called the gene fingerprint and defines genetic pathways associated with toxicity. The fingerprint siRNAs are inhibitors of toxicity since they remove gene pathways relevant to toxicity. If compounds also act as inhibitors of mhtt toxicity, they should act as an siRNA. Thus, the gene fingerprint defined by the siRNA should overlap with the fingerprint of a """"""""good"""""""" chemical inhibitor. The genetic fingerprint can be """"""""translated"""""""" into protein interactions to predict the actual targets of the inhibitor activity, and the pathways and targets are tested in models for disease. As an internal control, the fingerprinting methodology (Aim 2) is tested together with conventional screens to select for inhibitors to known disease- causing proteins (Aim 1). Inhibitors selected by the conventional methods are predicted to overlap with those identified from the global screen.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS060115-05
Application #
8116431
Study Section
Special Emphasis Panel (ZRG1-GGG-J (10))
Program Officer
Sutherland, Margaret L
Project Start
2007-07-01
Project End
2012-03-03
Budget Start
2011-07-01
Budget End
2012-03-03
Support Year
5
Fiscal Year
2011
Total Cost
$180,256
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
006471700
City
Rochester
State
MN
Country
United States
Zip Code
55905
Polyzos, Aris A; McMurray, Cynthia T (2017) The chicken or the egg: mitochondrial dysfunction as a cause or consequence of toxicity in Huntington's disease. Mech Ageing Dev 161:181-197
Polyzos, Aris A; McMurray, Cynthia T (2017) Close encounters: Moving along bumps, breaks, and bubbles on expanded trinucleotide tracts. DNA Repair (Amst) 56:144-155
Polyzos, Aris; Holt, Amy; Brown, Christopher et al. (2016) Mitochondrial targeting of XJB-5-131 attenuates or improves pathophysiology in HdhQ150 animals with well-developed disease phenotypes. Hum Mol Genet 25:1792-802
Budworth, Helen; McMurray, Cynthia T (2016) Problems and solutions for the analysis of somatic CAG repeat expansion and their relationship to Huntington's disease toxicity. Rare Dis 4:e1131885
Lai, Yanhao; Budworth, Helen; Beaver, Jill M et al. (2016) Crosstalk between MSH2-MSH3 and pol? promotes trinucleotide repeat expansion during base excision repair. Nat Commun 7:12465
Budworth, Helen; Harris, Faye R; Williams, Paul et al. (2015) Suppression of Somatic Expansion Delays the Onset of Pathophysiology in a Mouse Model of Huntington's Disease. PLoS Genet 11:e1005267
McMurray, Cynthia T; Vijg, Jan (2014) Editorial overview: Molecular and genetic bases of disease: the double life of DNA. Curr Opin Genet Dev 26:v-vii
Lee, Do-Yup; McMurray, Cynthia T (2014) Trinucleotide expansion in disease: why is there a length threshold? Curr Opin Genet Dev 26:131-40
Platt, Virginia; Lee, Do Yup; Canaria, Christie A et al. (2013) Towards understanding region-specificity of triplet repeat diseases: coupled immunohistology and mass spectrometry imaging. Methods Mol Biol 1010:213-30
Budworth, Helen; McMurray, Cynthia T (2013) Bidirectional transcription of trinucleotide repeats: roles for excision repair. DNA Repair (Amst) 12:672-84

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