Human iPSC-derived cerebral organoids model features of Leigh Syndrome and reveal abnormal corticogenesis
Leigh syndrome (LS) is a rare, inherited neurometabolic disorder that presents with bilateral brain lesions, caused by defects in the mitochondrial respiratory chain and associated nuclear-encoded proteins. We generated iPSCs from three patient-derived LS fibroblast lines and identified, by whole-exome and mitochondrial sequencing, unreported mutations in pyruvate dehydrogenase (GM0372, PDH; GM13411, MT-ATP6/PDH) and dihydrolipoyl dehydrogenase (GM01503, DLD). LS-derived iPSC lines were viable and generally capable of differentiating into key progenitor populations, but we identified several abnormalities in three-dimensional differentiation models of brain development. LS-derived cerebral organoids showed defects in neural epithelial bud generation, size, and cortical architecture at 100 days. The double mutant MT-ATP6/PDH line produced organoid neural progenitor cells with abnormal mitochondrial morphology characterized by fragmentation and disorganization and showed an increased generation of astrocytes. These studies aim to provide a comprehensive phenotypic characterization of available patient-derived cell lines that can be used as LS model systems.