Synaptic protein composition and localization in individuals with schizophrenia

I am a physician-scientist dedicated to caring for people with schizophrenia (SZ) and studying the pathophysiology of SZ to identify disease-modifying therapeutic interventions. Converging evidence in the field points to abnormalities in synapses, and perhaps a reduction in specific synaptic subtypes in distinct cortical layers due to ongoing synapse elimination, that may result in abnormal neuronal signaling that interfere with cognition. However, methodological limitations have impeded progress in testing the neuroanatomical basis of this hypothesis. In this project, a novel multiplex imaging method, Array Tomography, will be applied to a large cohort of dorsolateral prefrontal cortex (DLPFC) sections of postmortem brain samples from individuals with SZ and controls in combination with transcriptomic data to test whether individuals with SZ a have a lower synaptic density of excitatory and inhibitory synapses in layer 3 (L3) of the DLPFC that correlate with high C4A gene expression. Specific aims include: [1] Comparing both the synaptic density of excitatory and inhibitory synapses (and ratios of excitatory to inhibitory synapses) in DLPFC L3 from 55 SZ and 55 control donors, to test whether the synaptic density of either (or both) primary synaptic subtypes differs between SZ and controls, while also testing whether an imbalance in excitatory and inhibitory synaptic density could be the basis of the imbalance in excitatory and inhibitory signals that may be disrupting cognition (E/I imbalance). [2] determining the specificity of the synaptic density abnormalities in L3 by measuring the excitatory and inhibitory synaptic density in the same samples in layer 5, and [3] calculating the correlation between excitatory and inhibitory synaptic density in DLPFC L3 and C4A gene expression, as measured by bulk RNA- sequencing [RNA-seq]. Demonstrating a strong correlation between high C4A gene expression and low synaptic density would provide supporting evidence for the excessive synaptic pruning hypothesis and C4A gene expression as a primary mediator of synaptic density. Work on this project will provide empirical data for leading hypotheses in the field while supporting my Career Development. I will gain extensive experience in using Array Tomography to study detailed synaptic architecture and work towards identifying critical factors that regulate synapses in SZ by coupling with transcriptomic data. This experience will build on my prior experience so I can work on the underlying synaptic pathology in SZ using a combination of postmortem tissue and in vivo model systems as an independent investigator. Goals of this Career Development Award will be overseen by my primary mentor, Professor Urban, expert in -omis analyses in psychiatric disorders. An outstanding Mentoring Team at Stanford University will support my career development in gaining experience in using Array Tomography, bioinformatic analyses, deepening my knowledge of synaptic biology, while building the publication record and preliminary data for a successful transition to an independence.