Cellular mechanisms of early brain overgrowth in autistic children: elevated levels of GPX4 and resistance to ferroptosis
Autistic individuals with disproportionate megalencephaly (ASD-DM), characterized by enlarged brains relative to body height, have higher rates of intellectual disability and face more severe cognitive challenges than autistic children with average brain sizes. The cellular and molecular mechanisms underlying this neurophenotype remain poorly understood. To investigate these mechanisms, we generated human induced pluripotent stem cells from non-autistic typically developing children and autistic children with and without disproportionate megalencephaly. We assessed these children longitudinally from ages two to twelve years using magnetic resonance imaging and comprehensive cognitive and medical evaluations. We show that neural progenitor cells (NPCs) derived from ASD-DM children exhibit increased rates of cell survival and suppressed cell death, accompanied by heightened oxidative stress and ferrous iron accumulation. Despite these stressors, ASD-DM NPCs actively suppress apoptosis and ferroptosis by regulating proteins such as caspase-3 (CASP3), poly(ADP-ribose) polymerase 1 (PARP1), and glutathione peroxidase 4 (GPX4). Cellular ferroptotic signatures are further supported by elevated expression of selenocysteine genes, including GPX4, in the blood of ASD-DM children and their mothers, suggesting potential hereditary or environmental influences. Furthermore, we show that peripheral expression of GPX4 and other selenocysteine genes correlate with cognitive outcomes (IQ). These findings underscore the role of ferroptosis in autism, pointing to potential diagnostic biomarkers and targets for intervention.