Oligodendroglial dysfunction drives parvalbumin interneuron hypomyelination, circuit dysfunction and social deficits in an ASD model

Altered social behaviour in autism spectrum disorders (ASDs) has been linked to disruptions in neural circuit development, with emerging evidence implicating abnormal myelination. Yet how myelin development is affected and how this impacts circuit function remain unclear. Here, using the cntnap2-/- mouse model of ASD, we show that oligodendrocyte precursor cell (OPC) differentiation is transiently impaired during early postnatal development, resulting in delayed myelination in the somatosensory cortex and corpus callosum, altered myelin lipid composition, and impaired sheath wrapping, accompanied by transient microgliosis and increased oligodendrocyte apoptosis. Transcriptomic analysis reveals upregulation of interferon and immune-related pathways alongside downregulation of GABAergic synaptic genes in oligodendrocytes. These alterations converge on disrupted GABAergic interneuron to OPC communication, leading to hypomyelination and impaired maturation of parvalbumin-positive (PV) interneurons through a non-cell-autonomous mechanism, with selective deficits in PV function, excitation/inhibition balance and gamma oscillations. Early treatment with the promyelinating agents clemastine or pranlukast restores OPC differentiation, myelination, and PV maturation, rescues circuit dysfunction, and ameliorates social deficits and behavioural inflexibility. Our findings establish that transient developmental failure in OPC differentiation drives PV interneuron hypomyelination, linking oligodendroglial dysfunction to circuit-level and behavioural alterations in ASD, and highlight early myelin-targeted interventions as a potential therapeutic strategy.