Determining whether metabolic and mitochondrial pathophysiology are a common feature of three distinct genetic models of ASD

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In the last twenty years hundreds of potential genetic risk factors for autism have been identified. The mechanisms by which these genetic loci are linked to autism however are poorly understood, but many clues are coming from the use of animal models. Fragile X Syndrome (FXS), neurofibromatosis type 1 (NF1), and deletions in the Neurexin 1 gene (NRX1) are three such prevalent monogenic forms of autism, that are caused by loss of FMR1, NF1, and NRX1 gene function, respectively. Recent clinical findings suggest that, in addition to the well known behavioral and cognitive symptoms associated with these diseases, affected individuals also present with a variety of systemic phenotypes and metabolic abnormalities, likely due to the pleiotropic effects of the FMR1, NF1, and NRX1 genes. These findings come in hand with recent evidence implicating mitochondrial dysfunction in the pathogenesis of intellectual disability related syndromes and autism. Our prior studies, as well as that of others, have uncovered that Drosophila and mammalian models of FXS and NF1 have robust cellular signaling cascade defects, including decreased cAMP and increased insulin/PI3K signaling. The importance of these signaling defects is shown by the fact that our lab and others, have demonstrated that increasing cAMP levels is sufficient to restore behavior and cognition in Drosophila and murine models of FXS and NF1. We have also shown that reduction of insulin signaling in the Drosophila model of FXS ameliorates circadian and memory phenotypes. In our proposed studies we explore mitochondrial function in three Drosophila models of monogenetic forms of autism to determine if mitochondrial defects exist and if so, define commonalities and differences amongst them. We will also explore the impact that identified signaling pathway defects have on mitochondrial function in the NF1 and FXS models to determine if mitochondrial activity may be impacted by these signaling defects and thus contribute to the phenotypes displayed by these models.