Deficiency of intellectual disability-related gene Brpf1 reduced inhibitory neurotransmission and Map2k7 expression in GABAergic interneurons

Abstract

Intellectual disability is closely related to impaired GABA neurotransmission. Brpf1 was specifically expressed in medial ganglionic eminence (MGE), a developmental niche of GABAergic interneurons, and patients with BRPF1 mutations were mentally retarded. To test its role in development and function of MGE-derived GABAergic interneurons, we performed immunofluorescence staining, whole-cell patch-clamp, MGE transplantation and mRNA-Seq to understand its effect on neuronal differentiation, dendritic morphology, electrophysiology, migration and gene regulation, using mouse MGE-derived GABAergic interneurons infected with AAV-shBrpf1. We found a decreasing trend on parvalbumin+ interneuron differentiation. Moreover, increased firing threshold, decreased number of evoked APs, and a reduced amplitude of mIPSCs were observed before any significant change of MAP2+ dendritic morphology and in vivo migration appeared. Finally, mRNA-Seq analysis revealed that genes related to neurodevelopment and synaptic transmission such as Map2k7 were dysregulated. Our results demonstrated a key role of Brpf1 in inhibitory neurotransmission and related gene expression of GABAergic interneurons.