Medial Ganglionic Eminence and Cortical Organoids Model Human Brain Development and Interneuron Migration [RNA-seq]
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ABSTRACT: Organoid techniques provide unique platforms to model brain development and neurological disorders. While organoids recapitulating corticogenesis were established, a system modeling human medial ganglionic eminence (MGE) development, a critical ventral brain domain producing cortical interneurons and related lineages, remains to be developed. Here, we describe a system to generate MGE or cortex-specific organoids from human pluripotent stem cells. These organoids recapitulate the developments of MGE and cortex domains respectively. Population and single-cell transcriptomic profiling revealed transcriptional dynamics and lineage productions during MGE and cortical organoids development. Chromatin accessibility landscapes were found to be involved in this process. Furthermore, MGE and cortical organoids generated physiologically functional neurons and neuronal networks. Finally, we applied fusion organoids as a model to investigate human interneuron migration. Together, our study provides a new platform for generating domain-specific brain organoids, for modeling human interneuron migration, and offers deeper insight into molecular dynamics during human brain development.
Project description:Organoid techniques provide unique platforms to model brain development and neurological disorders. While organoids recapitulating corticogenesis were established, a system modeling human medial ganglionic eminence (MGE) development, a critical ventral brain domain producing cortical interneurons and related lineages, remains to be developed. Here, we describe a system to generate MGE or cortex-specific organoids from human pluripotent stem cells. These organoids recapitulate the developments of MGE and cortex domains respectively. Population and single-cell transcriptomic profiling revealed transcriptional dynamics and lineage productions during MGE and cortical organoids development. Chromatin accessibility landscapes were found to be involved in this process. Furthermore, MGE and cortical organoids generated physiologically functional neurons and neuronal networks. Finally, we applied fusion organoids as a model to investigate human interneuron migration. Together, our study provides a new platform for generating domain-specific brain organoids, for modeling human interneuron migration, and offers deeper insight into molecular dynamics during human brain development.
Project description:Organoid techniques provide unique platforms to model brain development and neurological disorders. While organoids recapitulating corticogenesis were established, a system modeling human medial ganglionic eminence (MGE) development, a critical ventral brain domain producing cortical interneurons and related lineages, remains to be developed. Here, we describe a system to generate MGE or cortex-specific organoids from human pluripotent stem cells. These organoids recapitulate the developments of MGE and cortex domains respectively. Population and single-cell transcriptomic profiling revealed transcriptional dynamics and lineage productions during MGE and cortical organoids development. Chromatin accessibility landscapes were found to be involved in this process. Furthermore, MGE and cortical organoids generated physiologically functional neurons and neuronal networks. Finally, we applied fusion organoids as a model to investigate human interneuron migration. Together, our study provides a new platform for generating domain-specific brain organoids, for modeling human interneuron migration, and offers deeper insight into molecular dynamics during human brain development.
Project description:Human embryonic stem cells with a GFP reporter knock-in into the NKX2.1 locus were differentiated and purified by FACS sorting for global gene expression analysis. Directed differentiation from human pluripotent stem cells (hPSCs) has seen significant progress in recent years. Most differentiated populations, however, exhibit immature properties of an early embryonic stage, raising concerns about their ability to model and treat disease. Here, we report the directed differentiation of hPSCs into medial ganglionic eminence (MGE)-like progenitors and their maturation into forebrain type interneurons. We find that early stage progenitors progress via a radial glial-like stem cell enriched in the human fetal brain. Both in vitro and post-transplantation into the rodent cortex, the MGE-like cells develop into GABAergic interneuron subtypes with mature physiological properties along a prolonged intrinsic timeline of up to seven months, mimicking endogenous human neural development. MGE-derived cortical interneuron deficiencies are implicated in a broad range of neurodevelopmental and degenerative disorders, highlighting the importance of these results for modeling human neural development and disease. Human embryonic stem cells with a GFP reporter knock-in into the NKX2.1 locus were differentiated for 20, 35, and 55 days in vitro and GFP+ cells were purified by FACS sorting. Total RNA was prepared from each timepoint and compared to undifferentiated human embryonic stem cells. hESC = one sample and three technical replicates. D20 = three independent samples. D35 = one sample and two technical replicates. D55 = one sample and one technical replicate.
Project description:In the mammalian cortex, about 60% of GABAergic interneurons, mainly including parvalbumin-expressing (PV+) and somatostatin (SST+) interneurons are generated from the medial ganglionic eminence (MGE) in the subpallium and tangentially migrate to the cortex. Here we analyze the role of the Sp9 transcription factor in regulating the development of MGE-derived cortical interneurons. We show that SP9 is widely expressed in the MGE subventricular zone (SVZ) and in MGE-derived migrating interneurons. By analyzing Sp9 null and conditional mutant mice, we demonstrate that Sp9 promotes MGE progenitor proliferation in the SVZ and is required for the normal patterning of tangential migration and the laminar distribution of MGE-derived cortical GABAergic interneurons. Loss of Sp9 function results in a ~50% reduction of MGE-derived cortical interneurons, an ectopic aggregation of MGE-derived neurons in the embryonic ventral telencephalon, and an increased ratio of SST+/PV+ cortical interneurons. Finally, we provide evidence that Sp9 regulates MGE derived cortical interneuron development through promoting expression of the Lhx6 and Lhx8 transcription factors.
Project description:Human embryonic stem cells with a GFP reporter knock-in into the NKX2.1 locus were differentiated and purified by FACS sorting for global gene expression analysis. Directed differentiation from human pluripotent stem cells (hPSCs) has seen significant progress in recent years. Most differentiated populations, however, exhibit immature properties of an early embryonic stage, raising concerns about their ability to model and treat disease. Here, we report the directed differentiation of hPSCs into medial ganglionic eminence (MGE)-like progenitors and their maturation into forebrain type interneurons. We find that early stage progenitors progress via a radial glial-like stem cell enriched in the human fetal brain. Both in vitro and post-transplantation into the rodent cortex, the MGE-like cells develop into GABAergic interneuron subtypes with mature physiological properties along a prolonged intrinsic timeline of up to seven months, mimicking endogenous human neural development. MGE-derived cortical interneuron deficiencies are implicated in a broad range of neurodevelopmental and degenerative disorders, highlighting the importance of these results for modeling human neural development and disease.
Project description:During development, newborn interneurons migrate throughout the embryonic brain. Here, we provide evidence that these interneurons act in a paracrine fashion to regulate developmental oligodendrocyte formation. Specifically, we show that medial ganglionic eminence (MGE) interneurons secrete factors that promote genesis of oligodendrocytes from glially-biased cortical precursors in culture. Moreover, when MGE interneurons are genetically ablated in vivo prior to their migration, this causes a deficit in cortical oligodendrogenesis. Modeling of the interneuron-precursor paracrine interaction using transcriptome data identifies the cytokine fractalkine as responsible for the pro-oligodendrocyte effect in culture. This paracrine interaction is important in vivo, since knockdown of the fractalkine receptor CX3CR1 in embryonic cortical precursors, or constitutive knockout of CX3CR1 causes decreased numbers of oligodendrocyte progenitor cells (OPCs) and oligodendrocytes in the postnatal cortex. Thus, in addition to their role in regulating neuronal excitability, interneurons act in a paracrine fashion to promote the developmental genesis of oligodendrocytes. We used microarrays to generate a list of expressed genes in purified medial ganglionic eminence (MGE) interneurons
Project description:Human brain development is a complex process involving neural proliferation, differentiation, and migration which are directed by many essential cellular factors and drivers. Here, using the NetBID2 algorithm and developing human brain RNA sequencing(RNA-Seq) dataset, we identified synaptotagmin-like 3(SYTL3) as one of the top drivers of early human brain development. Interestingly, SYTL3 exhibited high activity but low expression in both early developmental human cortex and human embryonic stem cell(hESC)-derived neurons. Knockout of SYTL3(SYTL3 -KO) in human neurons or knockdown of Sytl3 in embryonic mouse cortex markedly promoted neuronal migration. Besides, SYTL3-KO caused an abnormal distribution of deep-layer neurons in brain organoids and reduced presynaptic neurotransmitter release in hESC-derived neurons. We further demonstrated that SYTL3-KO- accelerated neuronal migration was modulated by high expression of matrix metalloproteinases. Together, based on bioinformatics and biological experiments, we identified SYTL3 as a novel regulator of cortical neuronal migration in human and mouse developing brains.
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:The Dlx homeodomain transcription factors are implicated in regulating the function of inhibitory GABAergic interneurons; therefore understanding their functions will provide insights into disorders such as epilepsy, mental retardation and autism. Identifying genes that are downstream of Dlx1/2 function and are relevant for the differentiation and survival of GABAergic interneurons. During embryonic development, cortical GABAergic interneurons are generated in the proliferative zone of the medial ganglionic eminence (MGE), from where they migrate to reach their final positions in the cortex. The differentiation of these interneuron precursors is dependent on Dlx genes, as shown by Dlx1/Dlx2 double mutants, which have a block in GABAergic cell differentiation and in cell migration. When interneuron progenitors are isolated from the mutant MGE and growth in culture, they are able to proceed along their differentiation program. However, mutant cells growth in vitro show defects in cell morphogenesis and increased cell apoptosis. We hypothesize that Dlx transcription factors regulate important aspects of GABAergic neuron differentiation such as the formation and growth of axon and dendrites, and the formation of inhibitory synapses. We generated E15.5 mouse embryos that are Dlx1/2 -/- or Dlx1/2 +/?. Genotype was confirmed by PCR. A total of 8 litters were used. For each experiment, we pooled tissue from at least 6 different embryos of the same genotype. We dissected the ventricular and subventricular zones of the MGE (rostral part). This area contains ~1 million of progenitor cells per embryo. We isolated total RNA using the Stratagene RNA Miniprep kit (these samples are called MGE+/ and MGE-/- in our proposal). In addition, we used the same area (ventricular and subventricular zones of the rostral MGE) to perform primary neuronal cultures. Cells were maintained 3 days in vitro. After that, we isolated total RNA using the Stratagene RNA Miniprep kit (samples called primary cells+/ and primary cells-/- in our proposal). We would like to perform gene expression comparison between: 1) MGE+/ and MGE-/-, and 2) primary cells+/ and primary cells-/-.