Project description:The connectivity, activity, and plasticity of the telencephalon are shaped by pallial and subpallial GABAergic neurons, two large populations that are produced in the embryonic medial, caudal and lateral ganglionic eminences in a highly complicated manner. Dysregulated development of GABAergic neurons is associated with neuropsychiatric disorders. However, knowledge about the specification of GABAergic neuron subtypes is limited. Here, using single-cell RNA sequencing combined with loss-of-function we delineated developmental trajectories and revealed transcriptional programs that specify GABAergic neuron subtypes in each GE lineage and transcription factors that direct lineage bifurcation decisions. Our study illuminates the control of production between pallial and subpallial populations and offers transcriptomic insights into the pathogenesis of GABAergic neuron-related disorders.
Project description:The connectivity, activity, and plasticity of the telencephalon are shaped by pallial and subpallial GABAergic neurons, two large populations that are produced in the embryonic medial, caudal and lateral ganglionic eminences in a highly complicated manner. Dysregulated development of GABAergic neurons is associated with neuropsychiatric disorders. However, knowledge about the specification of GABAergic neuron subtypes is limited. Here, using single-cell RNA sequencing combined with loss-of-function we delineated developmental trajectories and revealed transcriptional programs that specify GABAergic neuron subtypes in each GE lineage and transcription factors that direct lineage bifurcation decisions. Our study illuminates the control of production between pallial and subpallial populations and offers transcriptomic insights into the pathogenesis of GABAergic neuron-related disorders.
Project description:The connectivity, activity, and plasticity of the telencephalon are shaped by pallial and subpallial GABAergic neurons, two large populations that are produced in the embryonic medial, caudal and lateral ganglionic eminences in a highly complicated manner. Dysregulated development of GABAergic neurons is associated with neuropsychiatric disorders. However, knowledge about the specification of GABAergic neuron subtypes is limited. Here, using single-cell RNA sequencing combined with loss-of-function we delineated developmental trajectories and revealed transcriptional programs that specify GABAergic neuron subtypes in each GE lineage and transcription factors that direct lineage bifurcation decisions. Our study illuminates the control of production between pallial and subpallial populations and offers transcriptomic insights into the pathogenesis of GABAergic neuron-related disorders.
Project description:The ventricular-subventricular zone (V-SVZ) is the largest neurogenic region of the postnatal forebrain, containing neural stem cells (NSCs) that emerge from both the embryonic pallium and subpallium. Despite of this dual origin, glutamatergic neurogenesis declines rapidly after birth, while gabaergic neurogenesis persists throughout life. We performed single-cell RNA-sequencing (scRNA-Seq) of the postnatal dorsal V-SVZ for unravelling the mechanisms leading to pallial lineage germinal activity silencing. We show that pallial NSCs enter a state of deep quiescence, characterized by high BMP-signaling, reduced transcriptional activity and Hopx expression, whilst in contrast, subpallial NSCs remain primed for activation. Induction of deep quiescence is paralleled by a rapid blockade of glutamatergic neurons production and differentiation. Finally, manipulation of Bmpr1a demonstrates its key role in mediating these effects. Together, our results highlight a central role of BMP-signaling in synchronizing quiescence induction and blockade of neuronal differentiation to rapidly silence pallial germinal activity after birth.
Project description:The mammalian amygdala is located in the temporal lobe of the telencephalon and plays a key role in limbic processing. Recently, our group proposed a radial morphological model to understand the glutamatergic (pallial) part of this nuclear complex in terms of separate progenitor domains. This model explains the amygdala region as consisting of several adjacent developmental radial progenitor units, disposing their distinct periventricular, intermediate, and superficial strata from the ventricle to the pial surface. It was expected that cell populations belonging to specific progenitor domains would present greater molecular similarity to each other than to neighboring developmental units. In this work, we aim to corroborate the existence of several radial domains in the pallial amygdala at the transcriptomic level. snRNAseq experiments in the amygdala of adult mice of both sexes indicated that at low resolution, the whole pallial amygdala was found to divide into two super-radial domains distinguished by differential expression of Slc17a6 and Slc17a7; the former partly imitates molecularly the subpallial (output) amygdalar regions, whereas the rest of the pallial amygdala is molecularly more akin to the surrounding cortical areas. In addition, our snRNAseq transcriptomic analysis fully supports the postulated amygdalar radial model of four main radial domains.
Project description:In the embryonic telencephalon, the pallial-subpallial boundary (PSB) separates the dorsal Pax6+ pallium from the ventral Gsh2+ subpallium. Previous studies have revealed that this region is a source of cells that will populate both the olfactory bulb and basal telencephalic limbic system. However, the level of progenitor cell heterogeneity and developmental genetic regulation of this progenitor region remains to be fully elucidated. In this study we carried out a comprehensive analysis of gene expression patterns at the PSB, in addition to an examination of the combinatorial function of Pax6 and Gsh2 in the specification of the PSB. First, we reveal that the PSB is comprised of a complex mix of molecularly distinct progenitor pools. In addition, by analysis of single Sey, Gsh2, and Sey/Gsh2 double mutant mice, we demonstrate that both Pax6 and Gsh2 are directly required for major aspects of PSB progenitor specification. Our analysis also reveals that the establishment of the epidermal growth factor receptor positive lateral cortical stream migratory route to the basal telencephalon is Pax6 dependent. Thus, in addition to their well-characterized cross-repressive roles in dorsal/ventral patterning our analyses reveal important novel functions of Gsh2 and Pax6 in the regulation of PSB progenitor pool specification and patterning.
Project description:Pallial functional organization is mediated by the dynamic interplay of a broad spectrum of cellular and molecular cues that promote midline patterning, neurogenesis, axon guidance and neural connectivity. The regulators that orchestrate these seminal processes are still poorly understood. By employing a pallial conditional ablation model, we report that the transcriptional and epigenetic modulator, REST corepressor 2 (Rcor2) plays key roles in organizing the developing corticoseptal boundary. ChIP-seq and RNA-seq analyses reveal that Rcor2 modulates a diverse repertoire of classes of genes with essential roles in CC development, including pallial/subpallial patterning, cell fate specification and axon guidance.
Project description:Dravet syndrome (DS) is a devastating early onset refractory epilepsy syndrome caused by variants in the SCN1A gene. A disturbed GABAergic interneuron function is implicated in the progression to DS but the underlying developmental and pathophysiological mechanisms remain elusive, in particularly at the chromatin level. In this study, we utilized induced pluripotent stem cells (iPSCs) derived from DS cases and healthy donors to model disease-associated epigenetic abnormalities of GABAergic development. Employing the ATAC-Seq technique, we assessed chromatin accessibility at multiple time points (Day 0, Day 19, Day 35, and Day 65) of GABAergic differentiation. Additionally, we elucidated the effects of the commonly used anti-seizure drug valproic acid (VPA) on chromatin accessibility in GABAergic cells. The distinct dynamics in chromatin profile of DS iPSC predicted accelerated early GABAergic development, evident at D19, and diverged further from the pattern in control iPSC with continued differentiation, indicating a disrupted GABAergic maturation. Exposure to VPA at D65 reshaped the chromatin landscape at a variable extent in different iPSC-lines and rescued the observed dysfunctional development in some DS iPSC-GABA. This study provides the first comprehensive investigation on the chromatin landscape of GABAergic differentiation in DS-patient iPSC, offering valuable insights into the epigenetic dysregulations associated with interneuronal dysfunction in DS. Moreover, our detailed analysis of the chromatin changes induced by VPA in iPSC-GABA holds the potential to improve development of personalized and targeted anti-epileptic therapies.