For new drug and drug target discovery in neurological and neuropsychiatric disorders, transitioning from efficacy in cell-based assays to benefit in whole-animal models has always been difficult and uncertain. Ideally, drug discovery studies would be conducted, as much as possible, in whole-animal models of disease, but in vivo animal experiments are tremendously costly and time- consuming. Conversely, while cell line and primary culture-based assays are rapid and inexpensive, they are compromised by phenotypic changes when neurons are cultured and/or immortalized, and, importantly, by the normal 3-dimensional milieu and local inter-cellular interactions of brain tissue architecture being unavoidably lost. To help bridge this gap between cell-based and whole-animal efficacy studies, we have developed a series of intact brain tissue-based models for CNS disorders including stroke, Huntington's disease (HD), and Alzheimer's disease (AD). In our published studies, we have shown the utility of such assays in advancing a range of gene target identification and drug development programs. To support the use of these brain slice explant models in the context of larger-scale discovery efforts, we have developed numerous technological and process innovations over the last decade, including high-throughput brain slicing and biolistic gene gun devices for transfection of brain slices with disease-relevant genes and assay reporter constructs. The overarching goal of the present proposal is to solve the final rate-limiting barrier to full scalability of this approach, namely, the automation of brain slice-based assay endpoints. To date, all of the brain slice disease models we have developed have been analyzed using laborious manual endpoint assays;nevertheless, assay throughput has been sufficient to support the screening of hundreds to thousands of compounds or gene targets per year even with a modest-sized scientific team. Implementation of "turnkey" unbiased, automated microscopy and high-content analysis (HCA) platforms would increase the throughput of these assays by 10-fold or more, and enable full support of large-scale systems biology, bioinformatics, and drug discovery programs. Such a bridging stage of "high-throughput biology" screening between cell-based and whole-animal models should significantly increase the likelihood of success of drug and drug target discovery and development programs, by providing a preview of both efficacy as well as potential adverse off-target effects in intact neurl tissue assays before substantial time and financial commitments are made to full in vivo efficacy studies.
A major obstacle in drug discovery and development for neurological and neuropsychiatric disorders is the missing link between initial findings in laboratory assays using primary neurons and cell lines, and showing benefit in whole-animal models of disease. While brain tissue-based assays form a natural bridge between cell-based and whole-animal models, to date such assays, while biologically and clinically relevant, have not been automatable, and have thereby limited their applicability in larger-scale drug discovery efforts. Thus, the present proposal seeks to take advantage of recent advances in automated, image-based analysis for systems biology, bioinformatics, and drug and drug target discovery to create assay platforms that will support unbiased, automated, and fully scalable brain-slice based screening platforms that will be powerful new tools for increasing the likelihood of success and speed of drug discovery and development programs for CNS diseases.
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