High-content screening for TPI Deficiency therapeutics

Abstract/Project summary: TPI Df is a devastating untreatable childhood metabolic disease resulting in anemia, paralysis, irreversible brain damage and premature death. Numerous subtle amino acid substitutions in Triosephosphate Isomerase (TPI) are pathogenic and result in rapidly progressing multisystem disease. Importantly, all known pathogenic TPI Df mutations result in a protein that retains function and pathogenesis is known to result from increased turnover of the functioning protein by Protein Quality Control pathways (PQC). We have developed a human cellular TPI Df assay based on a cellular model of the “common” E104D mutation and implemented it for high-content, high-throughput imaging. We have used this model in a pilot screen and validated its utility to identify novel compounds that modulate mutant TPI protein levels in human cells. We have developed the assay to full HTS standards, and propose to screen the 225,000 member NIH MLSMR compound library to identify hit-to-lead compounds to develop into TPI Df small molecule therapies. We will validate hits in secondary assays for TPI stability and activity in TPI Df patient cells, prioritize them in a panel of in vitro toxicology and metabolism assays, examine structure activity relationships (SARs) of the lead compounds and substantially validate them in vivo using established Drosophila and mouse models that reflect the entire range of TPI Df disease severities. Overall, this project will discover initial therapies for development and test efficacy of our lead compounds in TPI Df models, including a newly validated mouse model.