Cortical neurons are specified during embryonic development but often acquire their mature properties at relatively late stages of postnatal development. This delay in terminal differentiation is particularly prominent for fast-spiking parvalbumin-expressing (PV+) interneurons, which play critical roles in regulating the function of the cerebral cortex. We found that the maturation of PV+ interneurons is triggered by neuronal activity and mediated by the transcriptional cofactor peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α). Developmental loss of PGC-1α prevents PV+ interneurons from acquiring unique structural, electrophysiological, synaptic, and metabolic features and disrupts their diversification into distinct subtypes. PGC-1α functions as a master regulator of the differentiation of PV+ interneurons by directly controlling gene expression through a transcriptional complex that includes ERRγ and Mef2c transcription factors. Our results uncover a molecular switch that translates neural activity into a specific transcriptional program, promoting the maturation of PV+ interneurons at the appropriate developmental stage.
Keywords: GABAergic; PGC-1α; cerebral cortex; development; gene expression; interneuron; maturation; metabolism; mitochondria; parvalbumin.
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