brain organoids
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Modeling human brain development and disease: the role of primary cilia
Neurodevelopmental disorders (NDDs) impose a global burden, affecting an increasing number of individuals. While some causative genes have been identified, understanding the human-specific mechanisms involved in these disorders remains limited. Traditional gene-driven approaches for modeling brain diseases have failed to capture the diverse and convergent mechanisms at play. Centrosomes and cilia act as intermediaries between environmental and intrinsic signals, regulating cellular behavior. Mutations or dosage variations disrupting their function have been linked to brain formation deficits, highlighting their importance, yet their precise contributions remain largely unknown. Hence, we aim to investigate whether the centrosome/cilia axis is crucial for brain development and serves as a hub for human-specific mechanisms disrupted in NDDs. Towards this direction, we first demonstrated species-specific and cell-type-specific differences in the cilia-genes expression during mouse and human corticogenesis. Then, to dissect their role, we provoked their ectopic overexpression or silencing in the developing mouse cortex or in human brain organoids. Our findings suggest that cilia genes manipulation alters both the numbers and the position of NPCs and neurons in the developing cortex. Interestingly, primary cilium morphology is disrupted, as we find changes in their length, orientation and number that lead to disruption of the apical belt and altered delamination profiles during development. Our results give insight into the role of primary cilia in human cortical development and address fundamental questions regarding the diversity and convergence of gene function in development and disease manifestation. It has the potential to uncover novel pharmacological targets, facilitate personalized medicine, and improve the lives of individuals affected by NDDs through targeted cilia-based therapies.
Integration of 3D human stem cell models derived from post-mortem tissue and statistical genomics to guide schizophrenia therapeutic development
Schizophrenia is a neuropsychiatric disorder characterized by positive symptoms (such as hallucinations and delusions), negative symptoms (such as avolition and withdrawal) and cognitive dysfunction1. Schizophrenia is highly heritable, and genetic studies are playing a pivotal role in identifying potential biomarkers and causal disease mechanisms with the hope of informing new treatments. Genome-wide association studies (GWAS) identified nearly 270 loci with a high statistical association with schizophrenia risk; however each locus confers only a small increase in risk therefore it is difficult to translate these findings into understanding disease biology that can lead to treatments. Induced pluripotent stem cell (iPSC) models are a tractable system to translate genetic findings and interrogate mechanisms of pathogenesis. Mounting research with patient-derived iPSCs has proposed several neurodevelopmental pathways altered in SCZ, such as neural progenitor cell (NPC) proliferation, imbalanced differentiation of excitatory and inhibitory cortical neurons. However, it is unclear what exactly these iPS models recapitulate, how potential perturbations of early brain development translates into illness in adults and how iPS models that represent fetal stages can be utilized to further drug development efforts to treat adult illness. I will present the largest transcriptome analysis of post-mortem caudate nucleus in schizophrenia where we discovered that decreased presynaptic DRD2 autoregulation is the causal dopamine risk factor for schizophrenia (Benjamin et al, Nature Neuroscience 2022 https://doi.org/10.1038/s41593-022-01182-7). We developed stem cell models from a subset of the postmortem cohort to better understand the molecular underpinnings of human psychiatric disorders (Sawada et al, Stem Cell Research 2020). We established a method for the differentiation of iPS cells into ventral forebrain organoids and performed single cell RNAseq and cellular phenotyping. To our knowledge, this is the first study to evaluate iPSC models of SZ from the same individuals with postmortem tissue. Our study establishes that striatal neurons in the patients with SCZ carry abnormalities that originated during early brain development. Differentiation of inhibitory neurons is accelerated whereas excitatory neuronal development is delayed, implicating an excitation and inhibition (E-I) imbalance during early brain development in SCZ. We found a significant overlap of genes upregulated in the inhibitory neurons in SCZ organoids with upregulated genes in postmortem caudate tissues from patients with SCZ compared with control individuals, including the donors of our iPS cell cohort. Altogether, we demonstrate that ventral forebrain organoids derived from postmortem tissue of individuals with schizophrenia recapitulate perturbed striatal gene expression dynamics of the donors’ brains (Sawada et al, biorxiv 2022 https://doi.org/10.1101/2022.05.26.493589).
Untitled Seminar
Heiko Luhmann (Germany) – How neuronal activity builds the cerebral cortex; Mary Tolcos (Australia) – Cortical development and fetal brain injury; Silvia Velasco (Australia) – Human brain organoids to study neurodevelopment and disease
Reversing autism-related phenotypes in human brain organoids
Synaptic alterations in the striatum drive ASD-related behaviors in mice
Stem cell approaches to understand acquired and genetic epilepsies
The Hsieh lab focuses on the mechanisms that promote neural stem cell self-renewal and differentiation in embryonic and adult brain. Using mouse models, video-EEG monitoring, viral techniques, and imaging/electrophysiological approaches, we elucidated many of the key transcriptional/epigenetic regulators of adult neurogenesis and showed aberrant new neuron integration in adult rodent hippocampus contribute to circuit disruption and seizure development. Building on this work, I will present our recent studies describing how GABA-mediated Ca2+ activity regulates the production of aberrant adult-born granule cells. In a new direction of my laboratory, we are using human induced pluripotent stem cells and brain organoid models as approaches to understand brain development and disease. Mutations in one gene, Aristaless-related homeobox (ARX), are of considerable interest since they are known to cause a common spectrum of neurodevelopmental disorders including epilepsy, autism, and intellectual disability. We have generated cortical and subpallial organoids from patients with poly-alanine expansion mutations in ARX. To understand the nature of ARX mutations in the organoid system, we are currently performing cellular, molecular, and physiological analyses. I will present these data to gain a comprehensive picture of the effect of ARX mutations in brain development. Since we do not understand how human brain development is affected by ARX mutations that contribute to epilepsy, we believe these studies will allow us to understand the mechanism of pathogenesis of ARX mutations, which has the potential to impact the diagnosis and care of patients.
Modeling human neurodevelopment and evolution using brain organoids
Using Human Stem Cells to Uncover Genetic Epilepsy Mechanisms
Reprogramming somatic cells to a pluripotent state via the induced pluripotent stem cell (iPSC) method offers an increasingly utilized approach for neurological disease modeling with patient-derived cells. Several groups, including ours, have applied the iPSC approach to model severe genetic developmental and epileptic encephalopathies (DEEs) with patient-derived cells. Although most studies to date involve 2-D cultures of patient-derived neurons, brain organoids are increasingly being employed to explore genetic DEE mechanisms. We are applying this approach to understand PMSE (Polyhydramnios, Megalencephaly and Symptomatic Epilepsy) syndrome, Rett Syndrome (in collaboration with Ben Novitch at UCLA) and Protocadherin-19 Clustering Epilepsy (PCE). I will describe our findings of robust structural phenotypes in PMSE and PCE patient-derived brain organoid models, as well as functional abnormalities identified in fusion organoid models of Rett syndrome. In addition to showing epilepsy-relevant phenotypes, both 2D and brain organoid cultures offer platforms to identify novel therapies. We will also discuss challenges and recent advances in the brain organoid field, including a new single rosette brain organoid model that we have developed. The field is advancing rapidly and our findings suggest that brain organoid approaches offers great promise for modeling genetic neurodevelopmental epilepsies and identifying precision therapies.
Application of Airy beam light sheet microscopy to examine early neurodevelopmental structures in 3D hiPSC-derived human cortical spheroids
The inability to observe relevant biological processes in vivo significantly restricts human neurodevelopmental research. Advances in appropriate in vitro model systems, including patient-specific human brain organoids and human cortical spheroids (hCSs), offer a pragmatic solution to this issue. In particular, hCSs are an accessible method for generating homogenous organoids of dorsal telencephalic fate, which recapitulate key aspects of human corticogenesis, including the formation of neural rosettes—in vitro correlates of the neural tube. These neurogenic niches give rise to neural progenitors that subsequently differentiate into neurons. Studies differentiating induced pluripotent stem cells (hiPSCs) in 2D have linked atypical formation of neural rosettes with neurodevelopmental disorders such as autism spectrum conditions. Thus far, however, conventional methods of tissue preparation in this field limit the ability to image these structures in three-dimensions within intact hCS or other 3D preparations. To overcome this limitation, we have sought to optimise a methodological approach to process hCSs to maximise the utility of a novel Airy-beam light sheet microscope (ALSM) to acquire high resolution volumetric images of internal structures within hCS representative of early developmental time points.
Brain Organoids and Next-Generation Assembloid Models to Study Human Development and Disease
Rethinking neuroconstructivism through brain organoids at single cell resolution
Following neuronal trajectories
Malformations of the human cerebral cortex represent a major cause of developmental disabilities. To date, animal models carrying mutations of genes so far identified in human patients with brain malformations only partially recapitulate the expected phenotypes and therefore do not provide reliable models to entirely understand the molecular and cellular mechanisms responsible for these disorders. Hence, we combine the in vivo mouse model and the human brain organoids in order to better comprehend the mechanisms involved in the migration of neurons during human development and tackle the causes of neurodevelopmental disorders. Our results show that we can model human brain development and disorders using human brain organoids and contribute to open new avenues to bridge the gap of knowledge between human brain malformations and existing animal models.
Braincils: Exploring the missing link between neuronal primary cilia dysfunction and neurodevelopmental disorders - hints from dental stem cell-derived brain organoids
Autism associated CASPR2 auto-immune antibodies modify the developmental trajectory and network activity in human brain organoids
Biocompatible scaffolds improve neuralization and reproducibility of stem cell-derived brain organoids
Generation and characterization of human ventral midbrain organoids derived from Parkinson’s disease-derived and control induced pluripotent stem cells
Generation of brain organoids with improved neural fate specificity and blockage of aberrant development of mesodermal-derived tissue
Modelling Synaptic Function using Human Brain Organoids with Micro-Electrode Arrays and Electron Microscopy Analysis
Human dorsal forebrain organoids help to elucidate cell type-specific effects of maternal immune activation on fetal cortical development
Identification of pro-angiogenic factors for in vitro vascularization of hiPSC-derived brain organoids
Revealing how tRNA splicing defects cause pontocerebellar hypoplasia using brain organoids
Neurodevelopmental effects of valproic acid exposure in human brain organoids
Midbrain organoids with microglia represent a promising tool for modelling and studying cell autonomous and non-cell autonomous mechanisms in PD at the brain tissue level
Uncovering neurobiological pathways involved in SETBP1 haploinsufficiency disorder during early development using human brain organoids
Comprehensive functional profiling of human brain organoids
FENS Forum 2024
A “breathing” brain model: Metabolic measurements in whole-brain organoids
FENS Forum 2024
Wnt3a supplementation induces specific hippocampal signature in murine brain organoids
High-throughput neural connectivity mapping in human brain organoids
FENS Forum 2024
Characterization of a new human co-culture model of endothelial cells, pericytes, and brain organoids in a microfluidic device
FENS Forum 2024
Characterization of ventral forebrain organoids derived from human induced pluripotent stem cells
FENS Forum 2024
Elevated synaptic pruning in microglia across patient-derived brain organoids
FENS Forum 2024
Human microglia cells in Alzheimer disease-derived brain organoids: Can it be a good model?
FENS Forum 2024
An innovative approach for conducting 3D electrophysiological recordings within intact brain organoids
FENS Forum 2024
Microstructural characterization of brain organoids
FENS Forum 2024
Investigating the development of the GABAergic system using human brain organoids
FENS Forum 2024
Modelling MSA disease through the generation of brain organoids
FENS Forum 2024
Modelling regional specification in brain organoids using a novel mesofluidic device
FENS Forum 2024
Studying glioblastoma invasion in brain organoids
FENS Forum 2024
Toward a comprehensive in vitro model of the human visual system: Three-dimensional assembloids integrating retinal and brain organoids
FENS Forum 2024
brain organoids coverage
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