Understanding Schizophrenia Risk Mechanisms Via Multimodal Analysis of Patient-derived Neurons and 3D Cortical Organoids and Correlation with Clinical and Cognitive Phenotypes - PROJECT SUMMARY: Schizophrenia (SCZ) is a complex polygenic disorder, encompassing a spectrum of positive and negative clinical symptoms and cognitive deficits that vary considerably between individuals. Unfortunately, progress in understanding the etiology and pathophysiology is hindered by the lack of appropriate models that adequately capture both the complex and heterogeneous nature of the genetic risk and the diversity of the phenotypic manifestations. The advent of induced pluripotent stem cell (hiPSC) technology provides an important new experimental platform to study the cellular and circuit function of human cells that contain an individual’s full complement of genomic risk alleles. Thus, the door is now opened to developing improved in vitro models that can enhance understanding in an integrated context, relating patient genomes and cellular variables to their clinical and cognitive phenotypes. In this proposal, we describe our established, systematic, and quantitative hiPSC pipeline that models the cumulative cellular effects of common SCZ genetic risk variants by selecting patient and control lines (CON) based on their SCZ polygenic risk score (PRS). hiPSC lines were generated from fibroblast donors in our NIMH Clinical Sibling Study, for which extensive clinical and cognitive data are available. On our 2D platform, we performed unbiased phenotypic discovery on cortical neurons derived from 13 high PRS SCZ hiPSCs and 15 low PRS CON hiPSCs using an array of physiological assays, done blind to patient information. From these experiments we have published a report with multiple preliminary associations between electrophysiological variables and patient clinical and cognitive phenotypes. Here, we propose to replicate and expand on these findings using an entirely new set of hIPSCs (17 SCZ, 15 CON), again chosen based on PRS. In Aim 1, using our 2D platform, we propose to replicate, expand, and examine in depth case/control phenotypes and associations between cellular measures and clinical and cognitive features observed in SCZ patients. In Aim 2, we propose to use 3D cortical organoids to confirm our prior voltage gated sodium channel (VGSC) and GABAergic phenotypes and to discover novel molecular and cellular alterations in early cortical development by performing a multi-modal set of assays that includes single cell electrophysiology, bulk and single cell RNA sequencing, proteomics, and metabolomics on our entire set of SCZ and CON hIPSCs (N=60). Together, the work in these Aims is designed to identify cellular phenotypes related to the etiology, pathophysiology, and symptomatology of schizophrenia, with the goal of identifying therapeutic targets and enabling precision psychiatry.
