Human iPSC-Derived Neural Model to Investigate Developmental and Functional Defects Associated with TANGO2 Deficiency Disorder

TANGO2 deficiency disorder (TDD) is a rare autosomal recessive metabolic encephalomyopathy characterized by recurrent metabolic crises, cardiac arrhythmias, rhabdomyolysis, and neurodevelopmental impairment. Although TANGO2 has been implicated in mitochondrial function, lipid metabolism, and cellular energy homeostasis, the molecular mechanisms underlying neurological involvement and the marked inter-individual clinical variability remain poorly understood. This project investigated the role of TANGO2 in neurodevelopment using patient-derived models, with a particular focus on determinants of disease severity versus resilience. Human induced pluripotent stem cells (hiPSCs) were generated from two siblings carrying identical compound heterozygous TANGO2 mutations but presenting divergent clinical outcomes: one severely affected symptomatic patient (TO1) and one asymptomatic patient (TO2). Healthy hiPSC lines were used as controls. Neuronal differentiation was performed using a long protocol to model early developmental stages, including neural rosette formation and neuroprogenitor specification, and a Neurogenin-2–based protocol to generate induced glutamatergic neurons (iGluNeurons). In parallel, patient-derived fibroblasts were used for a multi-omics approach integrating genomic and transcriptomic data. Morphological analyses revealed significant alterations in neural rosette organization in TO1-derived models, characterized by reduced rosette area, suggesting an early impact of TANGO2 loss on neurodevelopment. TO1-derived neuroprogenitors also displayed impaired migratory capacity, particularly at 48 hours, indicating a role for TANGO2 in regulating migration dynamics during early neurodevelopment. No comparable abnormalities were observed in TO2-derived cultures. Upon neuronal differentiation, neuronal identity and maturation were largely preserved; however, at later stages (DIV21), TO1-derived neuronal cultures exhibited cellular clustering, reduced cell density, and increased oxidative stress, consistent with enhanced neuronal vulnerability. These alterations were not detected in TO2-derived neurons. Functional assessment of iGluNeurons demonstrated impaired spontaneous network activity in TO1-derived neurons, characterized by reduced coordination and network flexibility. Consistently, extracellular glutamate release was significantly reduced in TO1-derived neurons at both 14 and 21 days in vitro. In contrast, TO2-derived neurons showed largely preserved electrophysiological properties, with only a mild reduction in burst spike rate that did not compromise network transmission. Mitochondrial analyses revealed no differences in mitochondrial length; however, both patient-derived neuronal models exhibited increased mitochondrial membrane potential, suggesting an early mitochondrial alteration associated with TANGO2 deficiency. Notably, increased mitophagy was observed exclusively in TO2-derived neurons, indicating enhanced mitochondrial quality control as a potential compensatory mechanism. Vitamin B5 (pantothenate) treatment partially rescued disease-associated alterations in TO1-derived models, improving neural rosette morphology, neuroprogenitor migration, oxidative stress levels, and neuronal network coordination, supporting the involvement of CoA-dependent metabolic pathways. Multi-omics analyses of patient-derived fibroblasts identified EP300 as a regulatory factor selectively associated with TO2. As EP300 is an acetyl-CoA–dependent acetyltransferase regulating autophagy in response to intracellular acetyl-CoA levels, and TANGO2 is linked to acyl-CoA metabolism, these findings suggest a link between CoA homeostasis and autophagy–mitophagy pathways as mechanisms of cellular resilience