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Shyti, R.

Publications and source records attributed to Shyti, R..

3 recordsLinked to original sources

YY1 mutations disrupt corticogenesis and cytoarchitecture through a cell-type specific rewiring of cell-autonomous and non-cell-autonomous transcriptional programs

Germline mutations of YY1 cause Gabriele-de Vries syndrome (GADEVS), a neurodevelopmental disorder featuring intellectual disability and a wide range of systemic manifestations. To dissect the cellular and molecular mechanisms underlying GADEVS, we combined large-scale imaging, single-cell multiomics and gene regulatory network reconstruction in 2D and 3D patient-derived physiopathologically relevant cell lineages. YY1 haploinsufficiency causes a pervasive alteration of cell type specific transcriptional networks, disrupting corticogenesis at the level of neural progenitors and terminally differentiated neurons, including cytoarchitectural defects reminiscent of GADEVS clinical features. Transcriptional alterations in neurons propagated to neighboring astrocytes through a major non-cell autonomous pro-inflammatory effect that grounds the rationale for modulatory interventions. Together, neurodevelopmental trajectories, synaptic formation and neuronal-astrocyte cross talk emerged as salient domains of YY1 dosage-dependent vulnerability. Mechanistically, cell-type resolved reconstruction of gene regulatory networks uncovered the regulatory interplay between YY1, NEUROG2 and ETV5 and its aberrant rewiring in GADEVS. Our findings underscore the reach of advanced in vitro models in capturing developmental antecedents of clinical features and exposing their underlying mechanisms to guide the search for targeted interventions.

neuroscience↗

GTF2I dosage regulates neuronal differentiation and social behavior in 7q11.23 neurodevelopmental disorders

Copy number variations at 7q11.23 cause neurodevelopmental disorders with shared and opposite manifestations. Deletion causes Williams-Beuren syndrome (WBS), while duplication causes 7q11.23 microduplication syndrome (7Dup). Converging evidence indicates GTF2I, from the 7q11.23 locus, is a key mediator of the cognitive-behavioral phenotypes associated with WBS and 7Dup. Here we integrate molecular profiling of patient-derived cortical organoids (COs) and transgenic mouse models to dissect 7q11.23 disease mechanisms. Proteomic and transcriptomic profiling of COs revealed opposite dynamics of neural progenitor proliferation and transcriptional imbalances, leading to precocious excitatory neuron production in 7Dup. The accelerated excitatory neuron production in 7Dup COs could be rescued by GTF2I knockdown. Transgenic mice with Gtf2i duplication recapitulated early neuronal differentiation defects and ASD-like behaviors. Remarkably, inhibition of LSD1, a downstream effector of GTF2I, was sufficient to rescue ASD-like phenotypes. We propose that the GTF2I-LSD1 axis constitutes a molecular pathway amenable to therapeutic intervention.

neuroscience↗

7q11.23 CNV alters protein synthesis and REST-mediated neuronal intrinsic excitability

Copy number variations (CNVs) at 7q11.23 cause Williams-Beuren (WBS) and 7q microduplication syndromes (7Dup), two neurodevelopmental disorders with shared and opposite cognitive-behavioral phenotypes. Using patient-derived and isogenic neurons, we integrated transcriptomics, translatomics and proteomics to elucidate the molecular underpinnings of this dosage effect. We found that 7q11.23 CNVs cause opposite alterations in neuronal differentiation and excitability. Genes related to neuronal transmission chiefly followed 7q11.23 dosage and appeared transcriptionally controlled, while translation and ribosomal protein genes followed the opposite trend and were post-transcriptionally buffered. Mechanistically, we uncovered REST regulon as a key mediator of observed phenotypes and rescued transcriptional and excitability alterations through REST inhibition. We identified downregulation of global protein synthesis, mGLUR5 and ERK-mTOR pathways activity in steady-state in both WBS and 7Dup, whereas BDNF stimulation rescued them specifically in 7Dup. Overall, we show that 7q11.23 CNVs alter protein synthesis and neuronal firing-established molecular and cellular phenotypes of neurodevelopmental disorders. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/511483v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@1b0fa99org.highwire.dtl.DTLVardef@146624org.highwire.dtl.DTLVardef@13dc89aorg.highwire.dtl.DTLVardef@13d098f_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗