Excitatory Dysfunction Drives Network and Calcium Handling Deficits in 16p11.2 Duplication Schizophrenia Induced Pluripotent Stem Cell–Derived Neurons
Euan Parnell, Lorenza Culotta, Marc P. Forrest, Hiba A. Jalloul, Blair L. Eckman, Daniel Loizzo, Katherine K.E. Horan, Marc Dos Santos, Nicolas H. Piguel, Derek J.C. Tai, Hanwen Zhang, Tracy S. Gertler, Dina Simkin, Alan R. Sanders, Michael E. Talkowski, Pablo V. Gejman, Evangelos Kiskinis, Jubao Duan, Peter Penzes
Abstract
BackgroundSchizophrenia (SCZ) is a debilitating psychiatric disorder with a large genetic contribution; however, its neurodevelopmental substrates remain largely unknown. Modeling pathogenic processes in SCZ using human iPSC-derived neurons (iNs) has emerged as a promising strategy. Copy number variations (CNV) confer high genetic risk for SCZ, with duplication of the 16p11.2 locus increasing risk 14.5 fold.MethodsTo dissect the contribution of excitatory (iEN) versus GABAergic (iGN) neurons to SCZ pathophysiology, we induced iNs from CRISPR-Cas9 isogenic and SCZ patient-derived iPSCs, and analyzed SCZ-related phenotypes in iEN monocultures and iEN/iGN cocultures.ResultsIn iEN/iGN cocultures, neuronal firing and synchrony was reduced at later, but not earlier, stages of in vitro development. These were fully recapitulated in iEN monocultures, indicating a primary role for excitatory neurons. Moreover, isogenic iENs showed reduced dendrite length and deficits in calcium handling. iENs from 16p11.2 duplication-carrying SCZ patients displayed overlapping deficits in network synchrony, dendrite arborization and calcium handling. Transcriptomic analysis of both iEN cohorts revealed molecular markers of disease related to the glutamatergic synapse, neuroarchitecture and calcium regulation.ConclusionsOur results indicate the presence of 16p11.2 duplication-dependent alterations in SCZ patient derived iEN. Transcriptomics and cellular phenotyping reveal overlap between isogenic and patient-derived iENs, suggesting a central role of glutamatergic, morphological and calcium dysregulation in 16p11.2 duplication-mediated pathogenesis. Moreover, excitatory dysfunction during early neurodevelopment is implicated as the basis of SCZ pathogenesis in 16p11.2 duplication carriers. Our results support network synchrony and calcium handling as outcomes directly linked to this genetic risk variant. Schizophrenia (SCZ) is a debilitating psychiatric disorder with a large genetic contribution; however, its neurodevelopmental substrates remain largely unknown. Modeling pathogenic processes in SCZ using human iPSC-derived neurons (iNs) has emerged as a promising strategy. Copy number variations (CNV) confer high genetic risk for SCZ, with duplication of the 16p11.2 locus increasing risk 14.5 fold. To dissect the contribution of excitatory (iEN) versus GABAergic (iGN) neurons to SCZ pathophysiology, we induced iNs from CRISPR-Cas9 isogenic and SCZ patient-derived iPSCs, and analyzed SCZ-related phenotypes in iEN monocultures and iEN/iGN cocultures. In iEN/iGN cocultures, neuronal firing and synchrony was reduced at later, but not earlier, stages of in vitro development. These were fully recapitulated in iEN monocultures, indicating a primary role for excitatory neurons. Moreover, isogenic iENs showed reduced dendrite length and deficits in calcium handling. iENs from 16p11.2 duplication-carrying SCZ patients displayed overlapping deficits in network synchrony, dendrite arborization and calcium handling. Transcriptomic analysis of both iEN cohorts revealed molecular markers of disease related to the glutamatergic synapse, neuroarchitecture and calcium regulation. Our results indicate the presence of 16p11.2 duplication-dependent alterations in SCZ patient derived iEN. Transcriptomics and cellular phenotyping reveal overlap between isogenic and patient-derived iENs, suggesting a central role of glutamatergic, morphological and calcium dysregulation in 16p11.2 duplication-mediated pathogenesis. Moreover, excitatory dysfunction during early neurodevelopment is implicated as the basis of SCZ pathogenesis in 16p11.2 duplication carriers. Our results support network synchrony and calcium handling as outcomes directly linked to this genetic risk variant.