A phenotypic screen for compounds that differentially affect excitatory and inhibitory neuronal signaling

Project SummaryMaintaining the appropriate balance of excitationEvsinhibitionIin the nervous system is essential for normal brain functionas disruptions in E I balance are associated with disorders such as autism spectrum disorderASDschizophreniaand seizuresDevelopment of therapeutics for ASD and schizophrenia has lagged due to their multifactorial etiology and challenges in modeling relevant biology in scalable in vitro assaysThe Optopatch platform recently developed at Q State Bioscienceswhich uses engineered optogenetic proteinscustom microscopesand softwaremakes it possible to simultaneously stimulateblue lightand recordred lightelectrical activity fromneurons withmillisecond temporal resolutionsingle cell spatial resolution and high signal to noise ratioIn addition to measurements of intrinsic excitabilitypatterned blue light can be used to probe synaptic connections by stimulating a subset of neurons and recording postsynaptic potentialsPSPsin all remaining cellsThe Optopatch assayswhich record signals in individual neuronscan be paired with fluorescent labels of inhibitory neurons to identify compounds that differentially affect signaling in excitatory and inhibitory cells and would be expected to shift the E I balanceIn Phase I of this projectwe propose toadapt the established Q State assays for intrinsic excitability and synaptic transmission to measure the E I balance andvalidate these assays using tool compounds and gene knockdowns expected to shift the E I balanceIn Phase IIwe propose toscreen annotated compound librariesconfirm that proteins targeted by compounds in the library can modulate the E I balanceandvalidate that identified targets can also shift the E I balance in human stem cell derived neurons and in rodent brain sliceThe identified protein targets will serve as a starting point for drug discoveryand identified FDAapproved compounds may be repurposed for new indicationsThe suite of tools developed here will pave a new path for developing E I modulating therapeutics for treating complex neurological disorders such as autism and schizophrenia Project Narrative The balance between excitatoryEand inhibitoryIsignaling in the brain is essential for healthy brain functiondisruptions in this delicate balance have been linked to multiplepoorly treated neurological disorders including depressionschizophreniaautismand epilepsyQ State has developed engineered proteins and custom microscopes that enable us to rapidly record excitatory and inhibitory signaling in thousands of neurons grown in a dishWe will screen a library of small molecules for compounds capable of tuning the E I balance and characterize the compounds to determine their likelihood of being developed into effective therapeutics for neurological conditions