Project description:Brain organoids provide unique platforms for modeling development and diseases by recapitulating the architecture of the embryonic brain. However, current organoid methods are limited by interior hypoxia and cell death due to insufficient surface diffusion, preventing generation of architecture representative of late developmental stages. Here, we establish the sliced neocortical organoid (SNO) system, which bypasses the diffusion limit to prevent cell death and sustains neurogenesis in organized neural progenitor zones throughout long-term cultures. This method leads to the formation of an expanded cortical plate that establishes distinct upper and deep cortical layers, resembling the third-trimester human neocortex. Using the SNO system, we further identify a critical role of WNT/β-Catenin signaling in regulating cortical neuron fate specification, which is disrupted by a psychiatric disorder-associated genetic mutation in patient iPSC-derived organoids. These results demonstrate the utility of SNOs as a model for investigating previously inaccessible human-specific late-stage cortical developmental and disease-relevant mechanisms
Project description:Induced pluripotent stem cell (iPSC)-derived cortical neurons present a powerful new model of neurological disease. Previous work has established that differentiation protocols produce cortical neurons but little has been done to characterise these at cellular resolution. In particular, it is unclear to what extent in vitro two-dimensional, relatively disordered culture conditions recapitulate the development of in vivo cortical layer identity. Single cell multiplex RT-qPCR was used to interrogate the expression of genes previously implicated in cortical layer or phenotypic identity in individual cells. Unexpectedly, 22.7% of neurons analysed frequently co-expressed canonical fetal deep and upper cortical layer markers, and this co-expression was also present at the level of translated protein. By comparing our results to available single cell RNA-seq data from human fetal and adult brain, we observed that this co-expression of layer markers was also seen in primary tissue. These results suggest that establishing neuronal layer identity in iPSC-derived or primary cortical neurons using canonical marker genes transcripts is unlikely to be informative. Single cell RNA-seq of 16 iPSC-derived cortical neurons. This dataset was used for normalization purposes for GSE67835.
Project description:Schizophrenia is one of the most wide-spread and complex mental disorders. To characterize the impact of schizophrenia, we performed single nucleus RNA sequencing (snRNA-seq) of >220,000 neurons from the dorsolateral prefrontal cortex of patients with schizophrenia and matched controls. Additionally, >115,000 neurons were analyzed topographically by immunohistochemistry. Compositional analysis of snRNA-seq data revealed a reduction in abundance of GABAergic neurons
and a concomitant increase in principal neurons, most pronounced for upper cortical layer subtypes, which was substantiated by histological analysis. Many neuronal subtypes showed extensive transcriptomic changes, the most dramatic - in upper layer GABAergic neurons, including downregulation in energy metabolism and upregulation in neurotransmission. Transcription factor network analysis demonstrated a developmental origin of transcriptomic changes. Finally, Visium
spatial transcriptomics further corroborated upper layer neuron vulnerability in schizophrenia. Overall, our results point towards general network impairment within upper cortical layers as a core substrate associated with schizophrenia symptomatology. Study is available on bioRxiv (https://doi.org/10.1101/2020.11.17.386458) and in upcoming publication.
Project description:Noonan syndrome (NS) is a genetic disorder mainly caused by gain-of-function mutations of SHP2. Although diverse neurological manifestations are commonly diagnosed in NS patients, mechanisms on how the SHP2 mutation induces the neurodevelopmental defects remain elusive. Here, we report that cortical organoids (NS-COs) derived from NS-induced pluripotent stem cells (iPSCs) exhibit developmental abnormalities, especially in excitatory neurons (ENs). Although NS-COs normally develop in appearance, single-cell transcriptomic analysis represented increment of EN population and overexpression of cortical layer markers in NS-COs. Surprisingly, EN subpopulation co-expressing upper layer marker SATB2 and deep layer maker CTIP2 was enriched in NS-COs during the cortical development. In parallel with the developmental disruptions, NS-COs also exhibited reduced synaptic connectivity. Collectively, our findings suggest that perturbed cortical layer identity and impeded neuronal connectivity account for the neurological manifestations of NS.
Project description:Induced pluripotent stem cell (iPSC)-derived cortical neurons present a powerful new model of neurological disease. Previous work has established that differentiation protocols produce cortical neurons but little has been done to characterise these at cellular resolution. In particular, it is unclear to what extent in vitro two-dimensional, relatively disordered culture conditions recapitulate the development of in vivo cortical layer identity. Single cell multiplex RT-qPCR was used to interrogate the expression of genes previously implicated in cortical layer or phenotypic identity in individual cells. Unexpectedly, 22.7% of neurons analysed frequently co-expressed canonical fetal deep and upper cortical layer markers, and this co-expression was also present at the level of translated protein. By comparing our results to available single cell RNA-seq data from human fetal and adult brain, we observed that this co-expression of layer markers was also seen in primary tissue. These results suggest that establishing neuronal layer identity in iPSC-derived or primary cortical neurons using canonical marker genes transcripts is unlikely to be informative.
Project description:Generation of human induced pluripotent stem cells (iPSCs) through reprogramming was a transformational change in the field of regenerative medicine that led to new possibilities for drug discovery and cell replacement therapy. Several protocols have been established to differentiate hiPSCs into neuronal lineages. However, low differentiation efficiency is one of the major drawbacks of these approaches. Here, we compared the efficiency of two methods of neuronal differentiation from iPSCs cultured in two different culture media, StemFlex Medium (SFM) and Essential 8 Medium (E8M). The results indicated that iPSCs cultured in E8M efficiently generated different types of neurons in a shorter time and without the growth of undifferentiated nonneuronal cells in the culture as compared with those generated from iPSCs in SFM. Furthermore, these neurons were validated as functional units immunocytochemically by confirming the expression of mature neuronal markers (i.e., NeuN, b tubulin, and Synapsin I) and whole cell patch-clamp recordings. Long-read single-cell RNA sequencing confirms the presence of upper and deep layer cortical layer excitatory and inhibitory neuronal subtypes in addition to small populations of GABAergic neurons in day 30 neuronal cultures. Pathway analysis in
Project description:Human brain organoids provide unique platforms for modeling development and diseases by recapitulating the architecture of the embryonic brain. However, current organoid methods are limited by interior hypoxia and cell death due to insufficient surface diffusion, preventing generation of architecture resembling late developmental stages. Here, we report the sliced neocortical organoid (SNO) system, which bypasses the diffusion limit to prevent cell death over long-term cultures. This method leads to sustained neurogenesis and formation of an expanded cortical plate that establishes distinct upper and deep cortical layers for neurons and astrocytes, resembling the third trimester embryonic human neocortex. Using the SNO system, we further identify a critical role of WNT/β-catenin signaling in regulating human cortical neuron subtype fate specification, which is disrupted by a psychiatric-disorder-associated genetic mutation in patient induced pluripotent stem cell (iPSC)-derived SNOs. These results demonstrate the utility of SNOs for investigating previously inaccessible human-specific, late-stage cortical development and disease-relevant mechanisms.