Biology subjects

Fjodorova, M.

Publications and source records attributed to Fjodorova, M..

3 recordsLinked to original sources

bioRxiv2025

Autism-associated oxysterol regulates GABAergic neurogenesis and subtype fates

Distorted GABAergic neurodevelopment is believed to underscore cortical network dysfunction that lies at the heart of neurodevelopmental disorders (NDD) such as autism and schizophrenia. GABAergic neuron diversity is sculptured by cortical environmental cues during protracted postmitotic differentiation. However, the mechanism by which the NDD environment influences GABAergic neuronal development remains largely unknown. Oxysterols are oxidized metabolites of cholesterol that can interact with developmental signaling pathways. Using an iPSC model recapitulating human forebrain GABAergic neuron development and single-cell transcriptomic profiling, we show that 24S, 25-epoxysterol, an NDD-affected oxysterol highly enriched in the fetal brain, promotes neurogenesis, and disturbs the composition of GABAergic neuronal subtypes. Moreover, pharmacological and genetic interrogation identified the liver X receptor as a regulatory pathway mediating the action of 24S, 25-epoxysterol. These findings provide insights into the roles of cholesterol metabolism in neuronal development and a potential mechanism by which dysregulated brain oxysterols contribute to the pathogenesis of NDD.

developmental biology↗

bioRxiv2025

Direct pathway bias and altered striatal neurogenesis in human iPSC models of 16p11.2 CNVs: Evidence from single-cell and functional analyses

Striatal medium spiny neurons (MSNs) control motor, cognitive, and social domains via direct (dMSNs) and indirect (iMSNs) basal ganglia pathways. Recent genomic analyses implicate striatal circuit dysfunction in neurodevelopmental disorders (NDDs) and highlight MSNs as a newly recognised cell type affected in schizophrenia, yet much NDD research still focuses on cortical interneurons and glutamatergic neurons, leaving MSN involvement understudied. Here, we use human iPSC-derived MSNs to demonstrate high-fidelity striatal development and explore 16p11.2 copy number variants (CNVs) - mutations predisposing carriers to autism spectrum disorder, schizophrenia, intellectual disability and other NDD conditions featuring basal ganglia deficits. By profiling both 16p11.2 duplication and deletion MSNs, we uncover reciprocal changes in MSN neurogenesis kinetics that converge on a dMSN fate bias. These shifts correspond to altered calcium signalling and enhanced firing upon direct-pathway activation. Our findings reveal a previously unappreciated role for MSN subtype imbalances in NDD pathogenesis and open new avenues for therapeutic intervention.

neuroscience↗

bioRxiv2021

Dysfunction of cAMP-PKA-calcium signaling axis in striatal medium spiny neurons: a role in schizophrenia and Huntington's disease pathogenesis

BackgroundStriatal medium spiny neurons (MSNs) are preferentially lost in Huntingtons disease. Genomic studies also implicate a direct role for MSNs in schizophrenia, a psychiatric disorder known to involve cortical neuron dysfunction. It remains unknown whether the two diseases share similar MSN pathogenesis or if neuronal deficits can be attributed to cell type-dependent biological pathways. Transcription factor BCL11B, which is expressed by all MSNs and deep layer cortical neurons, was recently proposed to drive selective neurodegeneration in Huntingtons disease and identified as a candidate risk gene in schizophrenia. MethodsUsing human stem cell-derived neurons lacking BCL11B as a model, we investigated cellular pathology in MSNs and cortical neurons in the context of these disorders. Integrative analyses between differentially expressed transcripts and published GWAS datasets identified cell type-specific disease-related phenotypes. ResultsWe uncover a role for BCL11B in calcium homeostasis in both neuronal types, while deficits in mitochondrial function and protein kinase A (PKA)-dependent calcium transients are detected only in MSNs. Moreover, BCL11B-deficient MSNs display abnormal responses to glutamate and fail to integrate dopaminergic and glutamatergic stimulation, a key feature of striatal neurons in vivo. Gene enrichment analysis reveals overrepresentation of disorder risk genes among BCL11B-regulated pathways, primarily relating to cAMP-PKA-calcium signaling axis and synaptic signaling. ConclusionsOur study indicates that Huntingtons disease and schizophrenia are likely to share neuronal pathogenesis where dysregulation of intracellular calcium levels is found in both striatal and cortical neurons. In contrast, reduction in PKA signaling and abnormal dopamine/glutamate receptor signaling is largely specific to MSNs.

neuroscience↗