Pluto Bioinformatics

GSE90036: Abnormal interneuron development in a new humanized mouse model of Arx dup24 which recapitulates the patients behavioural and fine motor alterations

Bulk RNA sequencing

The Aristaless-related homeobox (ARX) gene is a transcription factor involved in the development of GABAergic and cholinergic neurons in the forebrain. ARX mutations have been associated with a wide spectrum of neurodevelopemental disorders in humans, among which the most frequent, the 24 bp duplication in the protein polyalanine tract 2 (c.428_451dup24), gives rise to intellectual disability (ID), fine motor defects with or without epilepsy. To understand the physiological and functional consequences of this mutation, we generated and characterized a humanized mouse model carrying the c.428_451dup24 duplication (Arxdup24/0). Arxdup24/0 males presented with hyperactivity, enhanced stereotypies and altered contextual fear memory. Specific fine motor skills were also affected in Arxdup24/0 males, with reaching and grasping abilities alteration and fine motor coordination and balance defect. Transcriptome analysis of Arxdup24/0 forebrains at E15.5 showed a down-regulation of genes specifically expressed in interneurons associated with an up-regulation of interneuron silenced genes, suggesting abnormal interneuron development. Accordingly, interneuron migration and development were altered particularly in the cortex and the striatum between stages E15.5, P0 and adult. We also revealed a perturbation of the inhibitory/excitatory balance in Arxdup24/0 basolateral amygdala. Altogether, we showed that the c.428_451dup24 mutation modifies Arx function with a direct consequence on interneuron development, leading to hyperactivity and defects in precise motor movement control and in associative memory. Finally, we presented a new review of the clinical features of 33 male patients with ARX c.428_451dup24 mutation and showed striking similarities between their clinical features and the mouse phenotype. SOURCE: giovanni iaconoHolger Heyn CNAG,Centro Nacional de Análisis Genómico

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