RESUMO
The genetic architecture of autism spectrum disorder (ASD) is itself a diverse allelic spectrum that consists of rare de novo or inherited variants in hundreds of genes and common polygenic risk at thousands of loci. ASD susceptibility genes are interconnected at the level of transcriptional and protein networks, and many function as genetic regulators of neurodevelopment or synaptic proteins that regulate neural activity. So that the core underlying neuropathologies can be further elucidated, we emphasize the importance of first defining subtypes of ASD on the basis of the phenotypic signatures of genes in model systems and humans.
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Transtorno do Espectro Autista/genética , Predisposição Genética para Doença/genética , Herança Multifatorial/genética , Animais , Células Cultivadas , Variações do Número de Cópias de DNA , Modelos Animais de Doenças , Redes Reguladoras de Genes , Humanos , NeurogêneseRESUMO
Self-organizing three-dimensional cellular models derived from human pluripotent stem cells or primary tissue have great potential to provide insights into how the human nervous system develops, what makes it unique and how disorders of the nervous system arise, progress and could be treated. Here, to facilitate progress and improve communication with the scientific community and the public, we clarify and provide a basic framework for the nomenclature of human multicellular models of nervous system development and disease, including organoids, assembloids and transplants.
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Consenso , Sistema Nervoso , Organoides , Terminologia como Assunto , Humanos , Modelos Biológicos , Sistema Nervoso/citologia , Sistema Nervoso/patologia , Organoides/citologia , Organoides/patologia , Células-Tronco Pluripotentes/citologiaRESUMO
Long interspersed element-1 (LINE-1 or L1) is a repetitive DNA retrotransposon capable of duplication by a copy-and-paste genetic mechanism. Scattered throughout mammalian genomes, L1 is typically quiescent in most somatic cell types. In developing neurons, however, L1 can express and retrotranspose at high frequency. The L1 element can insert into various genomic locations including intragenic regions. These insertions can alter the dynamic of the neuronal transcriptome by changing the expression pattern of several nearby genes. The consequences of L1 genomic alterations in somatic cells are still under investigation, but the high level of mutagenesis within neurons suggests that each neuron is genetically unique. Furthermore, some neurological diseases, such as Rett syndrome and ataxia telangiectasia, misregulate L1 retrotransposition, which could contribute to some pathological aspects. In this review, we survey the literature related to neurodevelopmental retrotransposition and discuss possible relevance to neuronal function, evolution, and neurological disease.
Assuntos
Elementos Nucleotídeos Longos e Dispersos/fisiologia , Mutagênese Insercional , Sistema Nervoso/crescimento & desenvolvimento , Animais , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/metabolismo , Ataxia Telangiectasia/patologia , Evolução Biológica , Evolução Molecular , Interação Gene-Ambiente , Hominidae/genética , Humanos , Elementos Nucleotídeos Longos e Dispersos/genética , Sistema Nervoso/patologia , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Síndrome de Rett/genética , Síndrome de Rett/metabolismo , Síndrome de Rett/patologiaRESUMO
Advances in the field of human stem cells are often a source of public and ethical controversy. Researchers must frequently balance diverse societal perspectives on questions of morality with the pursuit of medical therapeutics and innovation. Recent developments in brain organoids make this challenge even more acute. Brain organoids are a new class of brain surrogate generated from human pluripotent stem cells (hPSCs). They have gained traction as a model for studying the intricacies of the human brain by using advancements in stem cell biology to recapitulate aspects of the developing human brain in vitro. However, recent observation of neural oscillations spontaneously emerging from these organoids raises the question of whether brain organoids are or could become conscious. At the same time, brain organoids offer a potentially unique opportunity to scientifically understand consciousness. To address these issues, experimental biologists, philosophers, and ethicists united to discuss the possibility of consciousness in human brain organoids and the consequent ethical and moral implications.
Assuntos
Estado de Consciência , Células-Tronco Pluripotentes , Humanos , Status Moral , Encéfalo , OrganoidesRESUMO
The use of antidepressants during pregnancy benefits the mother's well-being, but the effects of such substances on neurodevelopment remain poorly understood. Moreover, the consequences of early exposure to antidepressants may not be immediately apparent at birth. In utero exposure to selective serotonin reuptake inhibitors (SSRIs) has been related to developmental abnormalities, including a reduced white matter volume. Several reports have observed an increased incidence of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) after prenatal exposure to SSRIs such as sertraline, the most widely prescribed SSRI. The advent of human-induced pluripotent stem cell (hiPSC) methods and assays now offers appropriate tools to test the consequences of such compounds for neurodevelopment in vitro. In particular, hiPSCs can be used to generate cerebral organoids - self-organized structures that recapitulate the morphology and complex physiology of the developing human brain, overcoming the limitations found in 2D cell culture and experimental animal models for testing drug efficacy and side effects. For example, single-cell RNA sequencing (scRNA-seq) and electrophysiological measurements on organoids can be used to evaluate the impact of antidepressants on the transcriptome and neuronal activity signatures in developing neurons. While the analysis of large-scale transcriptomic data depends on dimensionality reduction methods, electrophysiological recordings rely on temporal data series to discriminate statistical characteristics of neuronal activity, allowing for the rigorous analysis of the effects of antidepressants and other molecules that affect the developing nervous system, especially when applied in combination with relevant human cellular models such as brain organoids.
Assuntos
Transtorno do Espectro Autista , Inibidores Seletivos de Recaptação de Serotonina , Gravidez , Feminino , Recém-Nascido , Animais , Humanos , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Transtorno do Espectro Autista/tratamento farmacológico , Transtorno do Espectro Autista/epidemiologia , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Encéfalo , OrganoidesRESUMO
Three Prime Repair Exonuclease 1 (TREX1) gene mutations have been associated with Aicardi-Goutières Syndrome (AGS) - a rare, severe pediatric autoimmune disorder that primarily affects the brain and has a poorly understood etiology. Microglia are brain-resident macrophages indispensable for brain development and implicated in multiple neuroinflammatory diseases. However, the role of TREX1 - a DNase that cleaves cytosolic nucleic acids, preventing viral- and autoimmune-related inflammatory responses - in microglia biology remains to be elucidated. Here, we leverage a model of human embryonic stem cell (hESC)-derived engineered microglia-like cells, bulk, and single-cell transcriptomics, optical and transmission electron microscopy, and three-month-old assembloids composed of microglia and oligodendrocyte-containing organoids to interrogate TREX1 functions in human microglia. Our analyses suggest that TREX1 influences cholesterol metabolism, leading to an active microglial morphology with increased phagocytosis in the absence of TREX1. Notably, regulating cholesterol metabolism with an HMG-CoA reductase inhibitor, FDA-approved atorvastatin, rescues these microglial phenotypes. Functionally, TREX1 in microglia is necessary for the transition from gliogenic intermediate progenitors known as pre-oligodendrocyte precursor cells (pre-OPCs) to precursors of the oligodendrocyte lineage known as OPCs, impairing oligodendrogenesis in favor of astrogliogenesis in human assembloids. Together, these results suggest routes for therapeutic intervention in pathologies such as AGS based on microglia-specific molecular and cellular mechanisms.
Assuntos
Diferenciação Celular , Colesterol , Exodesoxirribonucleases , Homeostase , Microglia , Oligodendroglia , Fosfoproteínas , Humanos , Exodesoxirribonucleases/metabolismo , Exodesoxirribonucleases/genética , Microglia/metabolismo , Diferenciação Celular/fisiologia , Oligodendroglia/metabolismo , Colesterol/metabolismo , Fosfoproteínas/metabolismo , Homeostase/fisiologia , Doenças Autoimunes do Sistema Nervoso/metabolismo , Doenças Autoimunes do Sistema Nervoso/genética , Malformações do Sistema Nervoso/metabolismo , Malformações do Sistema Nervoso/genética , Encéfalo/metabolismo , Células-Tronco Embrionárias Humanas/metabolismo , Organoides/metabolismoRESUMO
The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), which was rapidly declared a pandemic by the World Health Organization (WHO). Early clinical symptomatology focused mainly on respiratory illnesses. However, a variety of neurological manifestations in both adults and newborns are now well-documented. To experimentally determine whether SARS-CoV-2 could replicate in and affect human brain cells, we infected iPSC-derived human brain organoids. Here, we show that SARS-CoV-2 can productively replicate and promote death of neural cells, including cortical neurons. This phenotype was accompanied by loss of excitatory synapses in neurons. Notably, we found that the U.S. Food and Drug Administration (FDA)-approved antiviral Sofosbuvir was able to inhibit SARS-CoV-2 replication and rescued these neuronal alterations in infected brain organoids. Given the urgent need for readily available antivirals, these results provide a cellular basis supporting repurposed antivirals as a strategic treatment to alleviate neurocytological defects that may underlie COVID-19- related neurological symptoms.
Assuntos
Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Recém-Nascido , Humanos , Sofosbuvir/farmacologia , Sofosbuvir/uso terapêutico , Organoides , Antivirais/farmacologia , Antivirais/uso terapêutico , Encéfalo , Morte Celular , SinapsesRESUMO
Autism spectrum disorders (ASD) are complex neurodevelopmental diseases in which different combinations of genetic mutations may contribute to the phenotype. Using Rett syndrome (RTT) as an ASD genetic model, we developed a culture system using induced pluripotent stem cells (iPSCs) from RTT patients' fibroblasts. RTT patients' iPSCs are able to undergo X-inactivation and generate functional neurons. Neurons derived from RTT-iPSCs had fewer synapses, reduced spine density, smaller soma size, altered calcium signaling and electrophysiological defects when compared to controls. Our data uncovered early alterations in developing human RTT neurons. Finally, we used RTT neurons to test the effects of drugs in rescuing synaptic defects. Our data provide evidence of an unexplored developmental window, before disease onset, in RTT syndrome where potential therapies could be successfully employed. Our model recapitulates early stages of a human neurodevelopmental disease and represents a promising cellular tool for drug screening, diagnosis and personalized treatment.
Assuntos
Células-Tronco Pluripotentes Induzidas/citologia , Neurogênese , Síndrome de Rett/tratamento farmacológico , Síndrome de Rett/patologia , Proliferação de Células , Feminino , Fibroblastos/citologia , Humanos , Síndrome de Rett/genética , Sinapses , Inativação do Cromossomo XRESUMO
To support complex cognition, neuronal circuits must integrate information across multiple temporal scales, ranging from milliseconds to decades. Neuronal timescales describe the duration over which activity within a network persists, posing a putative explanatory mechanism for how information might be integrated over multiple temporal scales. Little is known about how timescales develop in human neural circuits or other model systems, limiting insight into how the functional dynamics necessary for cognition emerge. In our work, we show that neuronal timescales develop in a nonlinear fashion in human cortical organoids, which is partially replicated in dissociated rat hippocampus cultures. We use spectral parameterization of spiking activity to extract an estimate of neuronal timescale that is unbiased by coevolving oscillations. Cortical organoid timescales begin to increase around month 6 postdifferentiation. In rodent hippocampal dissociated cultures, we see that timescales decrease from in vitro days 13-23 before stabilizing. We speculate that cortical organoid development over the duration studied here reflects an earlier stage of a generalized developmental timeline in contrast to the rodent hippocampal cultures, potentially accounting for differences in timescale developmental trajectories. The fluctuation of timescales might be an important developmental feature that reflects the changing complexity and information capacity in developing neuronal circuits.NEW & NOTEWORTHY Neuronal timescales describe the persistence of activity within a network of neurons. Timescales were found to fluctuate with development in two model systems. In cortical organoids timescales increased, peaked, and then decreased throughout development; in rat hippocampal dissociated cultures timescales decreased over development. These distinct developmental models overlap to highlight a critical window in which timescales lengthen and contract, potentially indexing changes in the information capacity of neuronal systems.
Assuntos
Hipocampo , Neurônios , Organoides , Animais , Organoides/fisiologia , Organoides/citologia , Hipocampo/fisiologia , Hipocampo/citologia , Ratos , Humanos , Neurônios/fisiologia , Córtex Cerebral/fisiologia , Córtex Cerebral/citologia , Células Cultivadas , Potenciais de Ação/fisiologia , Fatores de TempoRESUMO
Psychiatric disorders are often distinguished from neurological disorders in that the former do not have characteristic lesions or findings from cerebrospinal fluid, electroencephalograms (EEGs), or brain imaging, and furthermore do not have commonly recognized convergent mechanisms. Psychiatric disorders commonly involve clinical diagnosis of phenotypic behavioral disturbances of mood and psychosis, often with a poorly understood contribution of environmental factors. As such, psychiatric disease has been challenging to model preclinically for mechanistic understanding and pharmaceutical development. This review compares commonly used animal paradigms of preclinical testing with evolving techniques of induced pluripotent cell culture with a focus on emerging three-dimensional models. Advances in complexity of 3D cultures, recapitulating electrical activity in utero, and disease modeling of psychosis, mood, and environmentally induced disorders are reviewed. Insights from these rapidly expanding technologies are discussed as they pertain to the utility of human organoid and other models in finding novel research directions, validating pharmaceutical action, and recapitulating human disease.
Assuntos
Transtornos Mentais , Doenças do Sistema Nervoso , Organoides , Animais , Humanos , Encéfalo/patologia , Transtornos Mentais/patologia , Modelos BiológicosRESUMO
Prenatal alcohol exposure is the foremost preventable etiology of intellectual disability and leads to a collection of diagnoses known as Fetal Alcohol Spectrum Disorders (FASD). Alcohol (EtOH) impacts diverse neural cell types and activity, but the precise functional pathophysiological effects on the human fetal cerebral cortex are unclear. Here, we used human cortical organoids to study the effects of EtOH on neurogenesis and validated our findings in primary human fetal neurons. EtOH exposure produced temporally dependent cellular effects on proliferation, cell cycle, and apoptosis. In addition, we identified EtOH-induced alterations in post-translational histone modifications and chromatin accessibility, leading to impairment of cAMP and calcium signaling, glutamatergic synaptic development, and astrocytic function. Proteomic spatial profiling of cortical organoids showed region-specific, EtOH-induced alterations linked to changes in cytoskeleton, gliogenesis, and impaired synaptogenesis. Finally, multi-electrode array electrophysiology recordings confirmed the deleterious impact of EtOH on neural network formation and activity in cortical organoids, which was validated in primary human fetal tissues. Our findings demonstrate progress in defining the human molecular and cellular phenotypic signatures of prenatal alcohol exposure on functional neurodevelopment, increasing our knowledge for potential therapeutic interventions targeting FASD symptoms.
Assuntos
Córtex Cerebral , Etanol , Vias Neurais , Neurogênese , Neurônios , Organoides , Feminino , Humanos , Masculino , Gravidez , Astrócitos/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Córtex Cerebral/citologia , Montagem e Desmontagem da Cromatina/efeitos dos fármacos , Montagem e Desmontagem da Cromatina/genética , Epigênese Genética/efeitos dos fármacos , Epigênese Genética/genética , Etanol/farmacologia , Transtornos do Espectro Alcoólico Fetal/etiologia , Transtornos do Espectro Alcoólico Fetal/genética , Feto/citologia , Perfilação da Expressão Gênica , Rede Nervosa/efeitos dos fármacos , Transtornos do Neurodesenvolvimento/induzido quimicamente , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia , Neurogênese/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Organoides/citologia , Organoides/efeitos dos fármacos , Organoides/patologia , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/genética , Proteômica , Sinapses/efeitos dos fármacos , Vias Neurais/efeitos dos fármacosRESUMO
Focal cortical dysplasia is a highly epileptogenic cortical malformation with few treatment options. Here, we generated human cortical organoids from patients with focal cortical dysplasia type II. Using this human model, we mimicked some focal cortical dysplasia hallmarks, such as impaired cell proliferation, the presence of dysmorphic neurons and balloon cells, and neuronal network hyperexcitability. Furthermore, we observed alterations in the adherens junctions zonula occludens-1 and partitioning defective 3, reduced polarization of the actin cytoskeleton, and fewer synaptic puncta. Focal cortical dysplasia cortical organoids showed downregulation of the small GTPase RHOA, a finding that was confirmed in brain tissue resected from these patients. Functionally, both spontaneous and optogenetically-evoked electrical activity revealed hyperexcitability and enhanced network connectivity in focal cortical dysplasia organoids. Taken together, our findings suggest a ventricular zone instability in tissue cohesion of neuroepithelial cells, leading to a maturational arrest of progenitors or newborn neurons, which may predispose to cellular and functional immaturity and compromise the formation of neural networks in focal cortical dysplasia.
Assuntos
Epilepsia , Malformações do Desenvolvimento Cortical do Grupo I , Malformações do Desenvolvimento Cortical , Encéfalo , Humanos , Recém-Nascido , NeurôniosRESUMO
LINE-1 (L1) elements are a class of transposons, comprising approximately 19% and 21% of the mouse and human genomes, respectively. L1 retrotransposons can reverse transcribe their own RNA sequence into a de novo DNA copy integrated into a new genomic location. This activity, known as retrotransposition, may induce genomic alterations, such as insertions and deletions. Interestingly, L1s can retrotranspose and generate more de novo L1 copies in brains than in other somatic tissues. Here, we describe for the first time interchromosomal translocation triggered by ectopic L1 retrotransposition in neural progenitor cells. Such an observation adds to the studies in neurological and psychiatric diseases that exhibited variation in L1 activity between diseased brains compared with controls, suggesting that L1 activity could be detrimental when de-regulated.
RESUMO
The complexity of the human brain creates a spectrum of sophisticated behavioral repertoires, such as language, tool use, self-awareness, symbolic thought, cultural learning, and consciousness. Understanding how the human brain achieves that has been a longstanding challenge for neuroscientists and may bring insights into the evolution of human cognition and disease states. Human pluripotent stem cells could differentiate into specialized cell types and tissues in vitro. From this pluripotent state, it is possible to generate models of the human brain, such as brain organoids. The recent observation that brain organoids can spontaneously develop complex neural network activity in a dish can help one understand how neural network oscillations evolve and vary between normal and disease states. Moreover, this finding can be leveraged to other applications outside medicine, including engineering and artificial intelligence. However, as the brain model technology becomes more complex, it raises a series of ethical and moral dilemmas. This article discusses the status of this technology, some of its current limitations, and a vision of the future.
RESUMO
The sensory and cognitive abilities of the mammalian neocortex are underpinned by intricate columnar and laminar circuits formed from an array of diverse neuronal populations. One approach to determining how interactions between these circuit components give rise to complex behavior is to investigate the rules by which cortical circuits are formed and acquire functionality during development. This review summarizes recent research on the development of the neocortex, from genetic determination in neural stem cells through to the dynamic role that specific neuronal populations play in the earliest circuits of neocortex, and how they contribute to emergent function and cognition. While many of these endeavors take advantage of model systems, consideration will also be given to advances in our understanding of activity in nascent human circuits. Such cross-species perspective is imperative when investigating the mechanisms underlying the dysfunction of early neocortical circuits in neurodevelopmental disorders, so that one can identify targets amenable to therapeutic intervention.
Assuntos
Neocórtex/citologia , Neocórtex/crescimento & desenvolvimento , Rede Nervosa/citologia , Rede Nervosa/crescimento & desenvolvimento , Células-Tronco Neurais/fisiologia , Neurônios/fisiologia , Animais , Humanos , LógicaRESUMO
Early epilepsy is a prominent feature in patients with CDKL5-deficiency disorder (CDD). The underlying mechanism for excessive excitability in CDD is largely unknown. The brain organoid model has been recently developed to resemble many critical features of early human brain development. Here, we used a brain organoid model to investigate the cellular electrophysiological basis for hyper-excitability in CDD patients. Our study employed cortical organoids derived from two CDD patients harboring the same CDKL5 mutation (R59X) and two controls from their healthy parents. Whole-cell patch-clamp recordings revealed higher action potential (AP) firing rate and lower rheobase in both CDD organoids, indicating increased intrinsic neuronal excitability. We further found dysfunction of voltage-gated ion channels in CDD neurons that leads to hyperexcitability, including higher Na+ and K+ current densities and a negative shift in Na+ channel activation. In contrast to neuronal properties, we found that glutamatergic neurotransmission and the electrophysiological properties of glial cells were not altered in CDD organoids. In support of our CDD findings, we further discovered similar electrophysiologic properties in cortical organoids derived from a Rett syndrome (RTT) patient, including alterations in AP firings and Na+ and K+ channel function suggesting a convergent mechanism. Together, our study suggests a critical role of intrinsic neuronal hyperexcitability and ion channel dysfunction, seen in early brain development in both CDD and RTT disorders. This investigation provides potential novel drug targets for developing treatments of early epilepsy in such disorders.
Assuntos
Epilepsia , Células-Tronco Pluripotentes Induzidas , Síndrome de Rett , Humanos , Organoides , Canais Iônicos , Síndrome de Rett/genética , Epilepsia/genética , Proteínas Serina-Treonina Quinases/genéticaRESUMO
Loss-of-function mutations in CDKL5 kinase cause severe neurodevelopmental delay and early-onset seizures. Identification of CDKL5 substrates is key to understanding its function. Using chemical genetics, we found that CDKL5 phosphorylates three microtubule-associated proteins: MAP1S, EB2 and ARHGEF2, and determined the phosphorylation sites. Substrate phosphorylations are greatly reduced in CDKL5 knockout mice, verifying these as physiological substrates. In CDKL5 knockout mouse neurons, dendritic microtubules have longer EB3-labelled plus-end growth duration and these altered dynamics are rescued by reduction of MAP1S levels through shRNA expression, indicating that CDKL5 regulates microtubule dynamics via phosphorylation of MAP1S. We show that phosphorylation by CDKL5 is required for MAP1S dissociation from microtubules. Additionally, anterograde cargo trafficking is compromised in CDKL5 knockout mouse dendrites. Finally, EB2 phosphorylation is reduced in patient-derived human neurons. Our results reveal a novel activity-dependent molecular pathway in dendritic microtubule regulation and suggest a pathological mechanism which may contribute to CDKL5 deficiency disorder.
Assuntos
Dendritos/metabolismo , Microtúbulos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Síndromes Epilépticas/genética , Síndromes Epilépticas/metabolismo , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/genética , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Fatores de Troca de Nucleotídeo Guanina Rho/genética , Fatores de Troca de Nucleotídeo Guanina Rho/metabolismo , Espasmos Infantis/genética , Espasmos Infantis/metabolismoRESUMO
Early-onset epileptic encephalopathies are severe disorders often associated with specific genetic mutations. In this context, the CDKL5 deficiency disorder (CDD) is a neurodevelopmental condition characterized by early-onset seizures, intellectual delay, and motor dysfunction. Although crucial for proper brain development, the precise targets of CDKL5 and its relation to patients' symptoms are still unknown. Here, induced pluripotent stem cells derived from individuals deficient in CDKL5 protein were used to generate neural cells. Proteomic and phosphoproteomic approaches revealed disruption of several pathways, including microtubule-based processes and cytoskeleton organization. While CDD-derived neural progenitor cells have proliferation defects, neurons showed morphological alterations and compromised glutamatergic synaptogenesis. Moreover, the electrical activity of CDD cortical neurons revealed hyperexcitability during development, leading to an overly synchronized network. Many parameters of this hyperactive network were rescued by lead compounds selected from a human high-throughput drug screening platform. Our results enlighten cellular, molecular, and neural network mechanisms of genetic epilepsy that could ultimately promote novel therapeutic opportunities for patients.
Assuntos
Síndromes Epilépticas , Animais , Síndromes Epilépticas/genética , Humanos , Camundongos , Neurônios/metabolismo , Proteínas Serina-Treonina Quinases , ProteômicaRESUMO
Reciprocal deletion and duplication of the 16p11.2 region is the most common copy number variation (CNV) associated with autism spectrum disorders. We generated cortical organoids from skin fibroblasts of patients with 16p11.2 CNV to investigate impacted neurodevelopmental processes. We show that organoid size recapitulates macrocephaly and microcephaly phenotypes observed in the patients with 16p11.2 deletions and duplications. The CNV dosage affects neuronal maturation, proliferation, and synapse number, in addition to its effect on organoid size. We demonstrate that 16p11.2 CNV alters the ratio of neurons to neural progenitors in organoids during early neurogenesis, with a significant excess of neurons and depletion of neural progenitors observed in deletions. Transcriptomic and proteomic profiling revealed multiple pathways dysregulated by the 16p11.2 CNV, including neuron migration, actin cytoskeleton, ion channel activity, synaptic-related functions, and Wnt signaling. The level of the active form of small GTPase RhoA was increased in both, deletions and duplications. Inhibition of RhoA activity rescued migration deficits, but not neurite outgrowth. This study provides insights into potential neurobiological mechanisms behind the 16p11.2 CNV during neocortical development.
Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Transtorno do Espectro Autista/genética , Transtorno Autístico/genética , Encéfalo , Deleção Cromossômica , Cromossomos Humanos Par 16/genética , Variações do Número de Cópias de DNA/genética , Humanos , Neurogênese/genética , Organoides , ProteômicaRESUMO
E3-ubiquitin ligase Cullin3 (Cul3) is a high confidence risk gene for autism spectrum disorder (ASD) and developmental delay (DD). To investigate how Cul3 mutations impact brain development, we generated a haploinsufficient Cul3 mouse model using CRISPR/Cas9 genome engineering. Cul3 mutant mice exhibited social and cognitive deficits and hyperactive behavior. Brain MRI found decreased volume of cortical regions and changes in many other brain regions of Cul3 mutant mice starting from early postnatal development. Spatiotemporal transcriptomic and proteomic profiling of embryonic, early postnatal and adult brain implicated neurogenesis and cytoskeletal defects as key drivers of Cul3 functional impact. Specifically, dendritic growth, filamentous actin puncta, and spontaneous network activity were reduced in Cul3 mutant mice. Inhibition of small GTPase RhoA, a molecular substrate of Cul3 ligase, rescued dendrite length and network activity phenotypes. Our study identified defects in neuronal cytoskeleton and Rho signaling as the primary targets of Cul3 mutation during brain development.