Pathological disruption of CELF2 shuttling causes neuronal hyperactivity, learning deficits, and seizures
Michelle Hua, et al.
Michelle Hua, et al.
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Research Article Clinical Research Development Genetics

Pathological disruption of CELF2 shuttling causes neuronal hyperactivity, learning deficits, and seizures

Abstract

De novo heterozygous variants in CUGBP Elav-like family member 2 (CELF2) have recently been associated with a rare neurodevelopmental disorder, yet the mechanisms linking specific variants to distinct clinical phenotypes remain poorly understood. Here, we reported a cohort of 18 individuals and provided evidence that variants causing CELF2 mislocalization, but not protein-null variants, were associated with seizures. Using proband-derived human cortical neurons and transgenic mouse models, we demonstrated that CELF2 underwent activity-dependent nucleocytoplasmic shuttling in excitatory neurons and that its cytoplasmic retention caused neuronal hyperactivity, elevated seizure susceptibility, and learning and memory deficits. We further found that cytoplasmic CELF2 regulated mRNAs critical for synaptic function and neuronal excitability and implicated in epileptic seizures and intellectual disability. Drug screening further identified AKT signaling as a key regulator of CELF2 nucleocytoplasmic shuttling and a candidate target for reversing neuronal hyperactivity. Together, our findings expand the clinical and genetic spectrum of CELF2-related neurodevelopmental disorders and establish a variant-specific mechanism that links CELF2 mislocalization to neuronal hyperactivity, seizures, and cognitive impairment.

Authors

Michelle Hua, Mohamad-Reza Aghanoori, Melissa J. MacPherson, Yi Ren, Shehani V. Siripala, Yifan Yang, Yvonne Yan Yan Or, Malea Nguyen, Robert Duba-Kiss, Daniel Feng, Laura Williams, Christopher J. Gafuik, GengYi Wang, Chloe Quelin, Boris Keren, Sarah Schuhmann, Georgia Vasileiou, Alexia Bourgois, Antonio Vitobello, Christophe Philippe, Zornitza Stark, Richard J. Leventer, George McGillivray, Frederic Tran Mau-Them, Marine Tessarech, Clément Prouteau, Phillis Lakeman, Mahdi M. Motazacker, Donald R. Latner, Raymond C. Caylor, Yvette van Ierland, Eloise Prijoles, Angie Lichty, Evangelos Theodorou, David A. Sweetser, Edward Steel, Jan Cobben, Majed J. Dasouki, Daniel G. Calame, Bertrand Isidor, Benjamin Cogné, Mitchell Kesler, Brooke Rackel, Isabel Clark, Deborah M. Kurrasch, G. Campbell Teskey, James Ellis, Guiqiong He, Scott D. Ryan, Douglas J. Mahoney, A. Micheil Innes, Jonathan R. Epp, Guang Yang

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Figure 5

CELF2 mutant in the cytoplasm binds mRNAs of seizure-related genes and regulators of intrinsic excitability.

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CELF2 mutant in the cytoplasm binds mRNAs of seizure-related genes and r...
(A) Scatterplot showing log2-transformed RIP-seq counts per million (CPM) for CELF2 versus IgG. Genes enriched ≥2-fold with FDR < 0.01 relative to IgG RIP and total input are in red. (B) Human Phenotype (HP) Ontology analysis of 1,192 CELF2-KI targets, showing top 8 enriched terms with log10-transformed adjusted P values. (C) Heatmap showing z-score–transformed expression levels of selected genes from the enriched HP Ontology terms across CELF2-KI RIP, IgG RIP, and total input samples. (D) CELF2-KI RIP enrichment (log2 fold-change of RIP/IgG) for 142 seizure-related genes (tier 1) (38), across 15 functional groups based on Gene Ontology (GO) terms. Wilcoxon’s signed-rank test; groups with significantly higher enrichment are in yellow. Box plots show the interquartile range (IQR), median (line), and 1.5× IQR (whiskers). (E) Dot plot showing enriched GO terms from the analysis of 514 tier 2 seizure-related genes, grouped into 5 equal-sized bins based on their CELF2-KI RIP enrichment, as shown on the left. The yellow dotted line marks a 2-fold change in RIP/IgG. The enriched GO terms are grouped into 4 Biological Process (BP) categories. Color indicates the number of genes mapped to each term, while dot size represents the adjusted P value. (F) Schematic diagram of glutamate synapse–related genes identified through KEGG analysis of CELF2-KI targets, accompanied by heatmaps showing their z-score transformed expression levels across CELF2-KI RIP, IgG RIP, and total input samples as in C. (G) Dot plot showing the top 6 enriched GO BP terms with fold enrichment values, from the analysis of 185 CELF2-KI target mRNA identified as dendritic mRNA (39). (H) Schematic of Wnt ligands and Frizzled receptors identified as CELF2-KI targets, with heatmaps showing their z-score expression levels as in C. GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes.