Transcriptomic analysis of ASD and IDD associated pathogenic MYT1L S707Q mutation in human cortical interneurons
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ABSTRACT: We have used our protocol for generating cortical interneurons from human stem cells to study gene expression changes caused by the (S707QfsX56) mutation in the MYT1L gene, using both patient derived (PD) and variant knock in (VKI) models.
Project description:We have used our protocol for generating cortical interneurons from human pluripotent stem cells to study MYT1L genome-wide occupancy in human cortical interneurons.
Project description:Mutations that reduce the function of MYT1L, a neuron-specific transcription factor, are associated with a syndromic neurodevelopmental disorder. Furthermore, MYT1L is routinely used as a pro-neural factor in fibroblast-to-neuron transdifferentiation. MYT1L has been hypothesized to play a role in the trajectory of neuronal specification and subtype specific maturation, but this hypothesis has not been directly tested, nor is it clear which neuron types are most impacted by MYT1L loss. In this study, we profiled 412,132 nuclei from the forebrains of wild-type and MYT1L-deficient mice at three developmental stages: E14 at the peak of neurogenesis, P1 when neurons in the six cortical layers have been born, and P21 when neurogenesis is complete and neurons are maturing, to examine the role of MYT1L levels in the trajectory of neuronal development. We found that MYT1L deficiency significantly disrupted the relative proportions of cortical excitatory neurons. Changes in gene expression were concentrated in excitatory neurons, suggesting that transcriptional effects of MYT1L deficiency are largely due to disruption of neuronal maturation programs. Most effects on gene expression were cell autonomous and persistent through development. In addition, while MYT1L can both activate and repress gene expression, the repressive effects were most sensitive to haploinsufficiency, and thus more likely mediate MYT1L syndrome. These findings illuminate the intricate role of MYT1L in orchestrating gene expression dynamics during neuronal development, providing insights into the molecular underpinnings of MYT1L syndrome.
Project description:Mutations that reduce the function of MYT1L, a neuron-specific transcription factor, are associated with a syndromic neurodevelopmental disorder. Furthermore, MYT1L is routinely used as a pro-neural factor in fibroblast-to-neuron transdifferentiation. MYT1L has been hypothesized to play a role in the trajectory of neuronal specification and subtype specific maturation, but this hypothesis has not been directly tested, nor is it clear which neuron types are most impacted by MYT1L loss. In this study, we profiled 412,132 nuclei from the forebrains of wild-type and MYT1L-deficient mice at three developmental stages: E14 at the peak of neurogenesis, P1 when neurons in the six cortical layers have been born, and P21 when neurogenesis is complete and neurons are maturing, to examine the role of MYT1L levels in the trajectory of neuronal development. We found that MYT1L deficiency significantly disrupted the relative proportions of cortical excitatory neurons. Changes in gene expression were concentrated in excitatory neurons, suggesting that transcriptional effects of MYT1L deficiency are largely due to disruption of neuronal maturation programs. Most effects on gene expression were cell autonomous and persistent through development. In addition, while MYT1L can both activate and repress gene expression, the repressive effects were most sensitive to haploinsufficiency, and thus more likely mediate MYT1L syndrome. These findings illuminate the intricate role of MYT1L in orchestrating gene expression dynamics during neuronal development, providing insights into the molecular underpinnings of MYT1L syndrome.
Project description:Mutations that reduce the function of MYT1L, a neuron-specific transcription factor, are associated with a syndromic neurodevelopmental disorder. Furthermore, MYT1L is routinely used as a pro-neural factor in fibroblast-to-neuron transdifferentiation. MYT1L has been hypothesized to play a role in the trajectory of neuronal specification and subtype specific maturation, but this hypothesis has not been directly tested, nor is it clear which neuron types are most impacted by MYT1L loss. In this study, we profiled 412,132 nuclei from the forebrains of wild-type and MYT1L-deficient mice at three developmental stages: E14 at the peak of neurogenesis, P1 when neurons in the six cortical layers have been born, and P21 when neurogenesis is complete and neurons are maturing, to examine the role of MYT1L levels in the trajectory of neuronal development. We found that MYT1L deficiency significantly disrupted the relative proportions of cortical excitatory neurons. Changes in gene expression were concentrated in excitatory neurons, suggesting that transcriptional effects of MYT1L deficiency are largely due to disruption of neuronal maturation programs. Most effects on gene expression were cell autonomous and persistent through development. In addition, while MYT1L can both activate and repress gene expression, the repressive effects were most sensitive to haploinsufficiency, and thus more likely mediate MYT1L syndrome. These findings illuminate the intricate role of MYT1L in orchestrating gene expression dynamics during neuronal development, providing insights into the molecular underpinnings of MYT1L syndrome.
Project description:Our group has reported that the histone methyltransferase DOT1L is necessary for proper cortical plate development and layer distribution of glutamatergic neurons, however, its specific role on cortical interneuron development has not yet been explored. Here, we demonstrate that DOT1L affects interneuron development in a cell-autonomous manner. Deletion of Dot1l in MGE-derived interneuron precursor cells results in an overall reduction and altered distribution of GABAergic interneurons in the cortical plate at postnatal day (P) 0. Furthermore, we observed an altered proportion of GABAergic interneurons in the cortex and striatum at P21 with a significant decrease in Parvalbumin (PVALB)-expressing interneurons. Altogether, our results indicate that reduced numbers of cortical interneurons upon DOT1L deletion results from altered postmitotic differentiation/maturation.
Project description:Cortical interneurons display a remarkable diversity in their morphology, physiological properties and connectivity. Elucidating the molecular determinants underlying this heterogeneity is essential for understanding interneuron development and function. We discovered that alternative splicing differentially regulates the integration of somatostatin- and parvalbumin-expressing interneurons into nascent cortical circuits through the cell-type specific tailoring of mRNAs. Specifically, we identified a role for the activity-dependent splicing regulator Rbfox1 in the development of cortical interneuron subtype specific efferent connectivity. Our work demonstrates that Rbfox1 mediates largely non-overlapping alternative splicing programs within two distinct but related classes of interneurons.
Project description:Single-cell RNA-sequencing of cortical GABAergic interneurons to characterize their transcriptional profiles at several timepoints across development - from their origins in the ganglionic eminences, upon migration to the cortex, settling in cortical laminae, and through maturation.