RESUMO
The complement system is an ancient collection of proteolytic cascades with well-described roles in regulation of innate and adaptive immunity. With the convergence of a revolution in complement-directed clinical therapeutics, the discovery of specific complement-associated targetable pathways in the central nervous system, and the development of integrated multi-omic technologies that have all emerged over the last 15 years, precision therapeutic targeting in Alzheimer disease and other neurodegenerative diseases and processes appears to be within reach. As a sensor of tissue distress, the complement system protects the brain from microbial challenge as well as the accumulation of dead and/or damaged molecules and cells. Additional more recently discovered diverse functions of complement make it of paramount importance to design complement-directed neurotherapeutics such that the beneficial roles in neurodevelopment, adult neural plasticity, and neuroprotective functions of the complement system are retained.
Assuntos
Doenças Neuroinflamatórias , Neuroproteção , Humanos , Animais , Encéfalo , Proteínas do Sistema Complemento , Plasticidade Neuronal/fisiologia , Microglia/fisiologiaRESUMO
The nicotinic acetylcholine receptor has served, since its biochemical identification in the 1970s, as a model of an allosteric ligand-gated ion channel mediating signal transition at the synapse. In recent years, the application of X-ray crystallography and high-resolution cryo-electron microscopy, together with molecular dynamic simulations of nicotinic receptors and homologs, have opened a new era in the understanding of channel gating by the neurotransmitter. They reveal, at atomic resolution, the diversity and flexibility of the multiple ligand-binding sites, including recently discovered allosteric modulatory sites distinct from the neurotransmitter orthosteric site, and the conformational dynamics of the activation process as a molecular switch linking these multiple sites. The model emerging from these studies paves the way for a new pharmacology based, first, upon the occurrence of an original mode of indirect allosteric modulation, distinct from a steric competition for a single and rigid binding site, and second, the design of drugs that specifically interact with privileged conformations of the receptor such as agonists, antagonists, and desensitizers. Research on nicotinic receptors is still at the forefront of understanding the mode of action of drugs on the nervous system.
Assuntos
Sítio Alostérico , Microscopia Crioeletrônica , Simulação de Dinâmica Molecular , Receptores Nicotínicos , Transdução de Sinais , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/química , Receptores Nicotínicos/genética , Regulação Alostérica , Humanos , Animais , Cristalografia por Raios X , Sítios de Ligação , Conformação Proteica , Ligantes , Modelos Moleculares , Multimerização Proteica , Agonistas Nicotínicos/química , Agonistas Nicotínicos/farmacologia , Agonistas Nicotínicos/metabolismoRESUMO
In addition to long-distance molecular motor-mediated transport, cellular vesicles also need to be moved at short distances with defined directions to meet functional needs in subcellular compartments but with unknown mechanisms. Such short-distance vesicle transport does not involve molecular motors. Here, we demonstrate, using synaptic vesicle (SV) transport as a paradigm, that phase separation of synaptic proteins with vesicles can facilitate regulated, directional vesicle transport between different presynaptic bouton sub-compartments. Specifically, a large coiled-coil scaffold protein Piccolo, in response to Ca2+ and via its C2A domain-mediated Ca2+ sensing, can extract SVs from the synapsin-clustered reserve pool condensate and deposit the extracted SVs onto the surface of the active zone protein condensate. We further show that the Trk-fused gene, TFG, also participates in COPII vesicle trafficking from ER to the ER-Golgi intermediate compartment via phase separation. Thus, phase separation may play a general role in short-distance, directional vesicle transport in cells.
Assuntos
Vesículas Revestidas pelo Complexo de Proteína do Envoltório , Retículo Endoplasmático , Vesículas Sinápticas , Animais , Vesículas Sinápticas/metabolismo , Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Retículo Endoplasmático/metabolismo , Cálcio/metabolismo , Complexo de Golgi/metabolismo , Ratos , Transporte Biológico , Terminações Pré-Sinápticas/metabolismo , Sinapsinas/metabolismo , Condensados Biomoleculares/metabolismo , Proteínas do Citoesqueleto/metabolismo , Separação de FasesRESUMO
Animals adapt to environmental conditions by modifying the function of their internal organs, including the brain. To be adaptive, alterations in behavior must be coordinated with the functional state of organs throughout the body. Here, we find that thyroid hormone-a regulator of metabolism in many peripheral organs-directly activates cell-type-specific transcriptional programs in the frontal cortex of adult male mice. These programs are enriched for axon-guidance genes in glutamatergic projection neurons, synaptic regulatory genes in both astrocytes and neurons, and pro-myelination factors in oligodendrocytes, suggesting widespread plasticity of cortical circuits. Indeed, whole-cell electrophysiology revealed that thyroid hormone alters excitatory and inhibitory synaptic transmission, an effect that requires thyroid hormone-induced gene regulatory programs in presynaptic neurons. Furthermore, thyroid hormone action in the frontal cortex regulates innate exploratory behaviors and causally promotes exploratory decision-making. Thus, thyroid hormone acts directly on the cerebral cortex in males to coordinate exploratory behaviors with whole-body metabolic state.
RESUMO
In developing brains, axons exhibit remarkable precision in selecting synaptic partners among many non-partner cells. Evolutionarily conserved teneurins are transmembrane proteins that instruct synaptic partner matching. However, how intracellular signaling pathways execute teneurins' functions is unclear. Here, we use in situ proximity labeling to obtain the intracellular interactome of a teneurin (Ten-m) in the Drosophila brain. Genetic interaction studies using quantitative partner matching assays in both olfactory receptor neurons (ORNs) and projection neurons (PNs) reveal a common pathway: Ten-m binds to and negatively regulates a RhoGAP, thus activating the Rac1 small GTPases to promote synaptic partner matching. Developmental analyses with single-axon resolution identify the cellular mechanism of synaptic partner matching: Ten-m signaling promotes local F-actin levels and stabilizes ORN axon branches that contact partner PN dendrites. Combining spatial proteomics and high-resolution phenotypic analyses, this study advanced our understanding of both cellular and molecular mechanisms of synaptic partner matching.
Assuntos
Axônios , Proteínas de Drosophila , Drosophila melanogaster , Proteínas do Tecido Nervoso , Neurônios Receptores Olfatórios , Transdução de Sinais , Sinapses , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios Receptores Olfatórios/metabolismo , Axônios/metabolismo , Sinapses/metabolismo , Actinas/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Encéfalo/metabolismo , Dendritos/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Tenascina , Proteínas rac de Ligação ao GTPRESUMO
To understand biological processes, it is necessary to reveal the molecular heterogeneity of cells by gaining access to the location and interaction of all biomolecules. Significant advances were achieved by super-resolution microscopy, but such methods are still far from reaching the multiplexing capacity of proteomics. Here, we introduce secondary label-based unlimited multiplexed DNA-PAINT (SUM-PAINT), a high-throughput imaging method that is capable of achieving virtually unlimited multiplexing at better than 15 nm resolution. Using SUM-PAINT, we generated 30-plex single-molecule resolved datasets in neurons and adapted omics-inspired analysis for data exploration. This allowed us to reveal the complexity of synaptic heterogeneity, leading to the discovery of a distinct synapse type. We not only provide a resource for researchers, but also an integrated acquisition and analysis workflow for comprehensive spatial proteomics at single-protein resolution.
Assuntos
Proteômica , Imagem Individual de Molécula , DNA , Microscopia de Fluorescência/métodos , Neurônios , ProteínasRESUMO
Neurons build synaptic contacts using different protein combinations that define the specificity, function, and plasticity potential of synapses; however, the diversity of synaptic proteomes remains largely unexplored. We prepared synaptosomes from 7 different transgenic mouse lines with fluorescently labeled presynaptic terminals. Combining microdissection of 5 different brain regions with fluorescent-activated synaptosome sorting (FASS), we isolated and analyzed the proteomes of 18 different synapse types. We discovered â¼1,800 unique synapse-type-enriched proteins and allocated thousands of proteins to different types of synapses (https://syndive.org/). We identify shared synaptic protein modules and highlight the proteomic hotspots for synapse specialization. We reveal unique and common features of the striatal dopaminergic proteome and discover the proteome signatures that relate to the functional properties of different interneuron classes. This study provides a molecular systems-biology analysis of synapses and a framework to integrate proteomic information for synapse subtypes of interest with cellular or circuit-level experiments.
Assuntos
Encéfalo , Proteoma , Sinapses , Animais , Camundongos , Encéfalo/metabolismo , Camundongos Transgênicos , Proteoma/metabolismo , Proteômica , Sinapses/metabolismo , Sinaptossomos/metabolismoRESUMO
Dysregulation of the immune system is a cardinal feature of opioid addiction. Here, we characterize the landscape of peripheral immune cells from patients with opioid use disorder and from healthy controls. Opioid-associated blood exhibited an abnormal distribution of immune cells characterized by a significant expansion of fragile-like regulatory T cells (Tregs), which was positively correlated with the withdrawal score. Analogously, opioid-treated mice also showed enhanced Treg-derived interferon-γ (IFN-γ) expression. IFN-γ signaling reshaped synaptic morphology in nucleus accumbens (NAc) neurons, modulating subsequent withdrawal symptoms. We demonstrate that opioids increase the expression of neuron-derived C-C motif chemokine ligand 2 (Ccl2) and disrupted blood-brain barrier (BBB) integrity through the downregulation of astrocyte-derived fatty-acid-binding protein 7 (Fabp7), which both triggered peripheral Treg infiltration into NAc. Our study demonstrates that opioids drive the expansion of fragile-like Tregs and favor peripheral Treg diapedesis across the BBB, which leads to IFN-γ-mediated synaptic instability and subsequent withdrawal symptoms.
Assuntos
Interferon gama , Transtornos Relacionados ao Uso de Opioides , Síndrome de Abstinência a Substâncias , Linfócitos T Reguladores , Animais , Camundongos , Analgésicos Opioides/administração & dosagem , Interferon gama/metabolismo , Transtornos Relacionados ao Uso de Opioides/metabolismo , Transtornos Relacionados ao Uso de Opioides/patologiaRESUMO
Decades of research have identified genetic factors and biochemical pathways involved in neurodegenerative diseases (NDDs). We present evidence for the following eight hallmarks of NDD: pathological protein aggregation, synaptic and neuronal network dysfunction, aberrant proteostasis, cytoskeletal abnormalities, altered energy homeostasis, DNA and RNA defects, inflammation, and neuronal cell death. We describe the hallmarks, their biomarkers, and their interactions as a framework to study NDDs using a holistic approach. The framework can serve as a basis for defining pathogenic mechanisms, categorizing different NDDs based on their primary hallmarks, stratifying patients within a specific NDD, and designing multi-targeted, personalized therapies to effectively halt NDDs.
Assuntos
Doenças Neurodegenerativas , Humanos , Doenças Neurodegenerativas/patologia , Proteostase , Agregação Patológica de Proteínas/metabolismo , Morte Celular , Citoesqueleto/metabolismoRESUMO
Learning has been associated with modifications of synaptic and circuit properties, but the precise changes storing information in mammals have remained largely unclear. We combined genetically targeted voltage imaging with targeted optogenetic activation and silencing of pre- and post-synaptic neurons to study the mechanisms underlying hippocampal behavioral timescale plasticity. In mice navigating a virtual-reality environment, targeted optogenetic activation of individual CA1 cells at specific places induced stable representations of these places in the targeted cells. Optical elicitation, recording, and modulation of synaptic transmission in behaving mice revealed that activity in presynaptic CA2/3 cells was required for the induction of plasticity in CA1 and, furthermore, that during induction of these place fields in single CA1 cells, synaptic input from CA2/3 onto these same cells was potentiated. These results reveal synaptic implementation of hippocampal behavioral timescale plasticity and define a methodology to resolve synaptic plasticity during learning and memory in behaving mammals.
Assuntos
Região CA1 Hipocampal , Hipocampo , Camundongos , Animais , Região CA1 Hipocampal/fisiologia , Hipocampo/fisiologia , Plasticidade Neuronal/fisiologia , Aprendizagem/fisiologia , Neurônios , Transmissão Sináptica/fisiologia , MamíferosRESUMO
Germline histone H3.3 amino acid substitutions, including H3.3G34R/V, cause severe neurodevelopmental syndromes. To understand how these mutations impact brain development, we generated H3.3G34R/V/W knock-in mice and identified strikingly distinct developmental defects for each mutation. H3.3G34R-mutants exhibited progressive microcephaly and neurodegeneration, with abnormal accumulation of disease-associated microglia and concurrent neuronal depletion. G34R severely decreased H3K36me2 on the mutant H3.3 tail, impairing recruitment of DNA methyltransferase DNMT3A and its redistribution on chromatin. These changes were concurrent with sustained expression of complement and other innate immune genes possibly through loss of non-CG (CH) methylation and silencing of neuronal gene promoters through aberrant CG methylation. Complement expression in G34R brains may lead to neuroinflammation possibly accounting for progressive neurodegeneration. Our study reveals that H3.3G34-substitutions have differential impact on the epigenome, which underlie the diverse phenotypes observed, and uncovers potential roles for H3K36me2 and DNMT3A-dependent CH-methylation in modulating synaptic pruning and neuroinflammation in post-natal brains.
Assuntos
DNA Metiltransferase 3A , Histonas , Animais , Camundongos , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA/genética , Metilases de Modificação do DNA/genética , Histonas/metabolismo , Doenças NeuroinflamatóriasRESUMO
We assembled a semi-automated reconstruction of L2/3 mouse primary visual cortex from â¼250 × 140 × 90 µm3 of electron microscopic images, including pyramidal and non-pyramidal neurons, astrocytes, microglia, oligodendrocytes and precursors, pericytes, vasculature, nuclei, mitochondria, and synapses. Visual responses of a subset of pyramidal cells are included. The data are publicly available, along with tools for programmatic and three-dimensional interactive access. Brief vignettes illustrate the breadth of potential applications relating structure to function in cortical circuits and neuronal cell biology. Mitochondria and synapse organization are characterized as a function of path length from the soma. Pyramidal connectivity motif frequencies are predicted accurately using a configuration model of random graphs. Pyramidal cells receiving more connections from nearby cells exhibit stronger and more reliable visual responses. Sample code shows data access and analysis.
Assuntos
Neocórtex , Animais , Camundongos , Microscopia Eletrônica , Neocórtex/fisiologia , Organelas , Células Piramidais/fisiologia , Sinapses/fisiologiaRESUMO
Although women experience significantly higher tau burden and increased risk for Alzheimer's disease (AD) than men, the underlying mechanism for this vulnerability has not been explained. Here, we demonstrate through in vitro and in vivo models, as well as human AD brain tissue, that X-linked ubiquitin specific peptidase 11 (USP11) augments pathological tau aggregation via tau deubiquitination initiated at lysine-281. Removal of ubiquitin provides access for enzymatic tau acetylation at lysines 281 and 274. USP11 escapes complete X-inactivation, and female mice and people both exhibit higher USP11 levels than males. Genetic elimination of usp11 in a tauopathy mouse model preferentially protects females from acetylated tau accumulation, tau pathology, and cognitive impairment. USP11 levels also strongly associate positively with tau pathology in females but not males. Thus, inhibiting USP11-mediated tau deubiquitination may provide an effective therapeutic opportunity to protect women from increased vulnerability to AD and other tauopathies.
Assuntos
Doença de Alzheimer , Tauopatias , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Caracteres Sexuais , Tauopatias/genética , Tauopatias/patologia , Tioléster Hidrolases/genética , Proteases Específicas de Ubiquitina , Proteínas tau/genéticaRESUMO
Sex hormones exert a profound influence on gendered behaviors. How individual sex hormone-responsive neuronal populations regulate diverse sex-typical behaviors is unclear. We performed orthogonal, genetically targeted sequencing of four estrogen receptor 1-expressing (Esr1+) populations and identified 1,415 genes expressed differentially between sexes or estrous states. Unique subsets of these genes were distributed across all 137 transcriptomically defined Esr1+ cell types, including estrous stage-specific ones, that comprise the four populations. We used differentially expressed genes labeling single Esr1+ cell types as entry points to functionally characterize two such cell types, BNSTprTac1/Esr1 and VMHvlCckar/Esr1. We observed that these two cell types, but not the other Esr1+ cell types in these populations, are essential for sex recognition in males and mating in females, respectively. Furthermore, VMHvlCckar/Esr1 cell type projections are distinct from those of other VMHvlEsr1 cell types. Together, projection and functional specialization of dimorphic cell types enables sex hormone-responsive populations to regulate diverse social behaviors.
Assuntos
Ciclo Estral/genética , Regulação da Expressão Gênica , Caracteres Sexuais , Comportamento Sexual Animal/fisiologia , Agressão , Animais , Aromatase/metabolismo , Transtorno Autístico/genética , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Feminino , Perfilação da Expressão Gênica , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Comportamento SocialRESUMO
Frontotemporal dementia (FTD) because of MAPT mutation causes pathological accumulation of tau and glutamatergic cortical neuronal death by unknown mechanisms. We used human induced pluripotent stem cell (iPSC)-derived cerebral organoids expressing tau-V337M and isogenic corrected controls to discover early alterations because of the mutation that precede neurodegeneration. At 2 months, mutant organoids show upregulated expression of MAPT, glutamatergic signaling pathways, and regulators, including the RNA-binding protein ELAVL4, and increased stress granules. Over the following 4 months, mutant organoids accumulate splicing changes, disruption of autophagy function, and build-up of tau and P-tau-S396. By 6 months, tau-V337M organoids show specific loss of glutamatergic neurons as seen in individuals with FTD. Mutant neurons are susceptible to glutamate toxicity, which can be rescued pharmacologically by the PIKFYVE kinase inhibitor apilimod. Our results demonstrate a sequence of events that precede neurodegeneration, revealing molecular pathways associated with glutamate signaling as potential targets for therapeutic intervention in FTD.
Assuntos
Cérebro/patologia , Proteína Semelhante a ELAV 4/genética , Ácido Glutâmico/metabolismo , Mutação/genética , Neurônios/patologia , Organoides/metabolismo , Splicing de RNA/genética , Proteínas tau/genética , Autofagia/efeitos dos fármacos , Autofagia/genética , Biomarcadores/metabolismo , Padronização Corporal/efeitos dos fármacos , Padronização Corporal/genética , Morte Celular/efeitos dos fármacos , Linhagem Celular , Humanos , Hidrazonas/farmacologia , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Morfolinas/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Organoides/efeitos dos fármacos , Organoides/ultraestrutura , Fosforilação/efeitos dos fármacos , Pirimidinas/farmacologia , Splicing de RNA/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Grânulos de Estresse/efeitos dos fármacos , Grânulos de Estresse/metabolismo , Sinapses/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
Mammals use glabrous (hairless) skin of their hands and feet to navigate and manipulate their environment. Cortical maps of the body surface across species contain disproportionately large numbers of neurons dedicated to glabrous skin sensation, in part reflecting a higher density of mechanoreceptors that innervate these skin regions. Here, we find that disproportionate representation of glabrous skin emerges over postnatal development at the first synapse between peripheral mechanoreceptors and their central targets in the brainstem. Mechanoreceptor synapses undergo developmental refinement that depends on proximity of their terminals to glabrous skin, such that those innervating glabrous skin make synaptic connections that expand their central representation. In mice incapable of sensing gentle touch, mechanoreceptors innervating glabrous skin still make more powerful synapses in the brainstem. We propose that the skin region a mechanoreceptor innervates controls the developmental refinement of its central synapses to shape the representation of touch in the brain.
Assuntos
Tronco Encefálico/metabolismo , Mecanorreceptores/metabolismo , Sinapses/metabolismo , Percepção do Tato/fisiologia , Potenciais de Ação/fisiologia , Animais , Animais Recém-Nascidos , Axônios/metabolismo , Canais Iônicos/metabolismo , Camundongos Knockout , Neurônios/metabolismo , Imagem Óptica , Optogenética , Pele/inervaçãoRESUMO
RTN4-binding proteins were widely studied as "NoGo" receptors, but their physiological interactors and roles remain elusive. Similarly, BAI adhesion-GPCRs were associated with numerous activities, but their ligands and functions remain unclear. Using unbiased approaches, we observed an unexpected convergence: RTN4 receptors are high-affinity ligands for BAI adhesion-GPCRs. A single thrombospondin type 1-repeat (TSR) domain of BAIs binds to the leucine-rich repeat domain of all three RTN4-receptor isoforms with nanomolar affinity. In the 1.65 Å crystal structure of the BAI1/RTN4-receptor complex, C-mannosylation of tryptophan and O-fucosylation of threonine in the BAI TSR-domains creates a RTN4-receptor/BAI interface shaped by unusual glycoconjugates that enables high-affinity interactions. In human neurons, RTN4 receptors regulate dendritic arborization, axonal elongation, and synapse formation by differential binding to glial versus neuronal BAIs, thereby controlling neural network activity. Thus, BAI binding to RTN4/NoGo receptors represents a receptor-ligand axis that, enabled by rare post-translational modifications, controls development of synaptic circuits.
Assuntos
Inibidores da Angiogênese/metabolismo , Encéfalo/metabolismo , Neurogênese , Neurônios/metabolismo , Proteínas Nogo/metabolismo , Receptores Nogo/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Adipocinas/metabolismo , Sequência de Aminoácidos , Animais , Axônios/metabolismo , Adesão Celular , Moléculas de Adesão Celular Neuronais/metabolismo , Complemento C1q/metabolismo , Dendritos/metabolismo , Glicosilação , Células HEK293 , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Ligantes , Camundongos Endogâmicos C57BL , Rede Nervosa/metabolismo , Polissacarídeos/metabolismo , Ligação Proteica , Domínios Proteicos , Deleção de Sequência , Sinapses/metabolismo , Transmissão Sináptica/fisiologiaRESUMO
Loss of the gene (Fmr1) encoding Fragile X mental retardation protein (FMRP) causes increased mRNA translation and aberrant synaptic development. We find neurons of the Fmr1-/y mouse have a mitochondrial inner membrane leak contributing to a "leak metabolism." In human Fragile X syndrome (FXS) fibroblasts and in Fmr1-/y mouse neurons, closure of the ATP synthase leak channel by mild depletion of its c-subunit or pharmacological inhibition normalizes stimulus-induced and constitutive mRNA translation rate, decreases lactate and key glycolytic and tricarboxylic acid (TCA) cycle enzyme levels, and triggers synapse maturation. FMRP regulates leak closure in wild-type (WT), but not FX synapses, by stimulus-dependent ATP synthase ß subunit translation; this increases the ratio of ATP synthase enzyme to its c-subunit, enhancing ATP production efficiency and synaptic growth. In contrast, in FXS, inability to close developmental c-subunit leak prevents stimulus-dependent synaptic maturation. Therefore, ATP synthase c-subunit leak closure encourages development and attenuates autistic behaviors.
Assuntos
Trifosfato de Adenosina/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Subunidades Proteicas/metabolismo , Animais , Linhagem Celular , Ciclo do Ácido Cítrico/fisiologia , Fibroblastos/metabolismo , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Células HEK293 , Humanos , Camundongos , Neurônios/metabolismo , RNA Mensageiro , Sinapses/metabolismoRESUMO
Human organoids recapitulating the cell-type diversity and function of their target organ are valuable for basic and translational research. We developed light-sensitive human retinal organoids with multiple nuclear and synaptic layers and functional synapses. We sequenced the RNA of 285,441 single cells from these organoids at seven developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable "developed" state at a rate similar to human retina development in vivo. Transcriptomes of organoid cell types converged toward the transcriptomes of adult peripheral retinal cell types. Expression of disease-associated genes was cell-type-specific in adult retina, and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in human retinas.
Assuntos
Diferenciação Celular/genética , Organoides/citologia , Organoides/metabolismo , Retina/citologia , Retina/metabolismo , Análise de Célula Única/métodos , Sinapses/fisiologia , Transcriptoma/genética , Técnicas de Cultura de Células/métodos , Linhagem Celular , Eletrofisiologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Predisposição Genética para Doença/genética , Humanos , Hibridização In Situ , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Microscopia Eletrônica , Família Multigênica , Naftoquinonas , Organoides/efeitos da radiação , Organoides/ultraestrutura , Retina/patologia , Retina/efeitos da radiaçãoRESUMO
Homeostasis of neural firing properties is important in stabilizing neuronal circuitry, but how such plasticity might depend on alternative splicing is not known. Here we report that chronic inactivity homeostatically increases action potential duration by changing alternative splicing of BK channels; this requires nuclear export of the splicing factor Nova-2. Inactivity and Nova-2 relocation were connected by a novel synapto-nuclear signaling pathway that surprisingly invoked mechanisms akin to Hebbian plasticity: Ca2+-permeable AMPA receptor upregulation, L-type Ca2+ channel activation, enhanced spine Ca2+ transients, nuclear translocation of a CaM shuttle, and nuclear CaMKIV activation. These findings not only uncover commonalities between homeostatic and Hebbian plasticity but also connect homeostatic regulation of synaptic transmission and neuronal excitability. The signaling cascade provides a full-loop mechanism for a classic autoregulatory feedback loop proposed â¼25 years ago. Each element of the loop has been implicated previously in neuropsychiatric disease.