Screening the functionality of PTEN variants and pharmacological candidates in vivo

About This Grant

PROJECT SUMMARY PTEN (Phosphatase and Tensin Homolog) is one of the strongest genes associated with autism spectrum disorders (ASDs) and one of the most highly pleiotropic. PTEN encodes a negative regulator of mTOR signaling – a central metabolic pathway controlling protein synthesis, cell growth, and survival, yet the mechanisms contributing to the considerable pleiotropy of PTEN mutations are not well understood. Here, we propose a highly innovative approach that leverages the unique features of zebrafish to illuminate basic neurodevelopmental mechanisms downstream of PTEN loss of function and rapidly screen the functionality of human PTEN variants and pharmacological candidates targeting these mechanisms. Our central goals are: (1) to screen the functionality of human PTEN variants in the developing vertebrate brain in vivo; and (2) to identify novel pharmacological suppressors of PTEN-associated phenotypes. Our central hypotheses are: (1) the in vivo functional effects of PTEN mutations will reveal novel genotype-phenotype correlations, expanding on existing in silico and in vitro analyses; and (2) targeting specific components of the mTOR pathway will selectively reverse these phenotypes. To test our hypotheses, we will perform in vivo zebrafish screens to assess the functionality of human PTEN variants in a developing vertebrate brain informed by multiple in silico and in vitro predictions (Aim 1); and conduct high-throughput pharmacological screens of mTOR-targeting compound libraries in zebrafish (Aim 2). Our team is uniquely suited to perform these experiments, given our complementary expertise in high-throughput zebrafish ASD gene mutant analyses (MPI Hoffman) and computational modeling of ASD gene variants (MPI Turner). The broader impact of this research is to establish a proof-of-principle for in vivo human variant and pharmacological screens in zebrafish and to illuminate basic mechanisms contributing to pleiotropy across neurodevelopmental disorder genes.