Biology subjects

den Hoed, J.

Publications and source records attributed to den Hoed, J..

3 recordsLinked to original sources

bioRxiv2025

Functional characterization of pathogenic SATB2 missense variants identifies distinct effects on chromatin binding and transcriptional activity

SATB2-associated syndrome is an autosomal dominant neurodevelopmental syndrome caused by genetic alterations in the transcription factor SATB2. The associated phenotype is variable, and genotype-phenotype correlation studies have not yet been able to explain differences in severity and symptoms across affected individuals. While haploinsufficiency is the most often described disease mechanism, with the majority of variants consisting of whole- or partial-gene deletions and protein truncating variants with predicted loss-of-function, approximately one-third of affected individuals carry a SATB2 missense variant with an unknown effect. In this study, we sought to functionally characterize these missense variants to uncover associated pathogenic mechanisms. We combined a set of human cell-based experiments to screen 31 etiological SATB2 missense variants for effects on nuclear localization, global chromatin binding, and transcriptional activity. Our data indicate partial loss-of-function effects for most of the studied missense variants, but identify at least eight variants with increased SATB2 function showing a combination (or subset) of features that include stronger co-localization with DNA, decreased nuclear protein mobility suggesting increased overall chromatin binding, and maintained or increased transcriptional activity. These results demonstrate that phenotypes associated with variants in SATB2 may have distinct underlying disease mechanisms, and the data could provide a resource for future studies investigating disease variability and potential therapies for this condition.

genetics↗

bioRxiv2024

The chromatin remodeler CHD3 is highly expressed in mature neurons and regulates genes involved in synaptic development and function

Changes in the dynamics of chromatin state that control spatiotemporal gene expression patterns are crucial during brain development. CHD3 is a chromatin remodeler that is highly expressed during neurogenesis and that functions as a core member of the NuRD complex, a large multiprotein complex mediating chromatin state. Genetic disruptions in CHD3 have been implicated in a neurodevelopmental disorder characterized by intellectual disability, macrocephaly and severe speech deficits. To study the roles of CHD3 during early human brain development, we generated induced pluripotent stem cells with heterozygous and homozygous loss-of-function mutations, differentiated them into unguided neural organoids and cortical neurons, and analyzed these by immunohistochemistry, bulk RNA-, single-cell RNA-, and ChIP-sequencing. Loss of CHD3 expression had no detectable effects on early neuroepithelium formation and organoid growth, nor did it significantly affect cell type composition or neuronal differentiation speed. Instead, upon loss of CHD3, we observed dysregulation of genes related to axon guidance and synapse development across all datasets, identifying a novel role for the protein as a regulator that facilitates neurogenesis, in particular neuronal maturation. Our results based on genetically engineered knockout organoids pave the way for future studies modeling the neurobiological pathways affected in CHD3-related disorder.

neuroscience↗

bioRxiv2020

Mutation-specific pathophysiological mechanisms define different neurodevelopmental disorders associated with SATB1 dysfunction

Whereas large-scale statistical analyses can robustly identify disease-gene relationships, they do not accurately capture genotype-phenotype correlations or disease mechanisms. We use multiple lines of independent evidence to show that different variant types in a single gene, SATB1, cause clinically overlapping but distinct neurodevelopmental disorders. Clinical evaluation of 42 individuals carrying SATB1 variants identified overt genotype-phenotype relationships, associated with different pathophysiological mechanisms, established by functional assays. Missense variants in the CUT1 and CUT2 DNA-binding domains result in stronger chromatin binding, increased transcriptional repression and a severe phenotype. Contrastingly, variants predicted to result in haploinsufficiency are associated with a milder clinical presentation. A similarly mild phenotype is observed for individuals with premature protein truncating variants that escape nonsense-mediated decay and encode truncated proteins, which are transcriptionally active but mislocalized in the cell. Our results suggest that in-depth mutation-specific genotype-phenotype studies are essential to capture full disease complexity and to explain phenotypic variability.

genetics↗