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Ferroptosis, a non-apoptotic form of programmed cell death, is triggered by oxidative stress in cancer, heat stress in plants, and hemorrhagic stroke. A homeostatic transcriptional response to ferroptotic stimuli is unknown. We show that neurons respond to ferroptotic stimuli by induction of selenoproteins, including antioxidant glutathione peroxidase 4 (GPX4). Pharmacological selenium (Se) augments GPX4 and other genes in this transcriptional program, the selenome, via coordinated activation of the transcription factors TFAP2c and Sp1 to protect neurons. Remarkably, a single dose of Se delivered into the brain drives antioxidant GPX4 expression, protects neurons, and improves behavior in a hemorrhagic stroke model. Altogether, we show that pharmacological Se supplementation effectively inhibits GPX4-dependent ferroptotic death as well as cell death induced by excitotoxicity or ER stress, which are GPX4 independent. Systemic administration of a brain-penetrant selenopeptide activates homeostatic transcription to inhibit cell death and improves function when delivered after hemorrhagic or ischemic stroke.
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Isquemia Encefálica , Peptídeos Penetradores de Células/farmacologia , Ferroptose/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Hemorragias Intracranianas , Neurônios , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/biossíntese , Selênio/farmacologia , Acidente Vascular Cerebral , Transcrição Gênica/efeitos dos fármacos , Animais , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Modelos Animais de Doenças , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Hemorragias Intracranianas/tratamento farmacológico , Hemorragias Intracranianas/metabolismo , Hemorragias Intracranianas/patologia , Masculino , Camundongos , Neurônios/metabolismo , Neurônios/patologia , Fator de Transcrição Sp1/metabolismo , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/patologia , Fator de Transcrição AP-2/metabolismoRESUMO
The reduced ability of the central nervous system to regenerate with increasing age limits functional recovery following demyelinating injury. Previous work has shown that myelin debris can overwhelm the metabolic capacity of microglia, thereby impeding tissue regeneration in aging, but the underlying mechanisms are unknown. In a model of demyelination, we found that a substantial number of genes that were not effectively activated in aged myeloid cells displayed epigenetic modifications associated with restricted chromatin accessibility. Ablation of two class I histone deacetylases in microglia was sufficient to restore the capacity of aged mice to remyelinate lesioned tissue. We used Bacillus Calmette-Guerin (BCG), a live-attenuated vaccine, to train the innate immune system and detected epigenetic reprogramming of brain-resident myeloid cells and functional restoration of myelin debris clearance and lesion recovery. Our results provide insight into aging-associated decline in myeloid function and how this decay can be prevented by innate immune reprogramming.
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Neuropsychiatric disorders classically lack defining brain pathologies, but recent work has demonstrated dysregulation at the molecular level, characterized by transcriptomic and epigenetic alterations1-3. In autism spectrum disorder (ASD), this molecular pathology involves the upregulation of microglial, astrocyte and neural-immune genes, the downregulation of synaptic genes, and attenuation of gene-expression gradients in cortex1,2,4-6. However, whether these changes are limited to cortical association regions or are more widespread remains unknown. To address this issue, we performed RNA-sequencing analysis of 725 brain samples spanning 11 cortical areas from 112 post-mortem samples from individuals with ASD and neurotypical controls. We find widespread transcriptomic changes across the cortex in ASD, exhibiting an anterior-to-posterior gradient, with the greatest differences in primary visual cortex, coincident with an attenuation of the typical transcriptomic differences between cortical regions. Single-nucleus RNA-sequencing and methylation profiling demonstrate that this robust molecular signature reflects changes in cell-type-specific gene expression, particularly affecting excitatory neurons and glia. Both rare and common ASD-associated genetic variation converge within a downregulated co-expression module involving synaptic signalling, and common variation alone is enriched within a module of upregulated protein chaperone genes. These results highlight widespread molecular changes across the cerebral cortex in ASD, extending beyond association cortex to broadly involve primary sensory regions.
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Transtorno do Espectro Autista , Córtex Cerebral , Variação Genética , Transcriptoma , Humanos , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/metabolismo , Transtorno do Espectro Autista/patologia , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Neurônios/metabolismo , RNA/análise , RNA/genética , Transcriptoma/genética , Autopsia , Análise de Sequência de RNA , Córtex Visual Primário/metabolismo , Neuroglia/metabolismoRESUMO
Spinal cord injury in mammals is thought to trigger scar formation with little regeneration of axons1-4. Here we show that a crush injury to the spinal cord in neonatal mice leads to scar-free healing that permits the growth of long projecting axons through the lesion. Depletion of microglia in neonatal mice disrupts this healing process and stalls the regrowth of axons, suggesting that microglia are critical for orchestrating the injury response. Using single-cell RNA sequencing and functional analyses, we find that neonatal microglia are transiently activated and have at least two key roles in scar-free healing. First, they transiently secrete fibronectin and its binding proteins to form bridges of extracellular matrix that ligate the severed ends of the spinal cord. Second, neonatal-but not adult-microglia express several extracellular and intracellular peptidase inhibitors, as well as other molecules that are involved in resolving inflammation. We transplanted either neonatal microglia or adult microglia treated with peptidase inhibitors into spinal cord lesions of adult mice, and found that both types of microglia significantly improved healing and axon regrowth. Together, our results reveal the cellular and molecular basis of the nearly complete recovery of neonatal mice after spinal cord injury, and suggest strategies that could be used to facilitate scar-free healing in the adult mammalian nervous system.
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Microglia/fisiologia , Traumatismos da Medula Espinal/terapia , Regeneração da Medula Espinal , Medula Espinal/citologia , Medula Espinal/fisiologia , Animais , Animais Recém-Nascidos , Axônios/efeitos dos fármacos , Axônios/fisiologia , Cicatriz , Fibronectinas/metabolismo , Homeostase , Camundongos , Microglia/efeitos dos fármacos , Inibidores de Proteases/farmacologia , RNA-Seq , Análise de Célula Única , Medula Espinal/patologia , Traumatismos da Medula Espinal/patologia , Regeneração da Medula Espinal/efeitos dos fármacos , Cicatrização/efeitos dos fármacosRESUMO
The peripheral branch of sensory dorsal root ganglion (DRG) neurons regenerates readily after injury unlike their central branch in the spinal cord. However, extensive regeneration and reconnection of sensory axons in the spinal cord can be driven by the expression of α9 integrin and its activator kindlin-1 (α9k1), which enable axons to interact with tenascin-C. To elucidate the mechanisms and downstream pathways affected by activated integrin expression and central regeneration, we conducted transcriptomic analyses of adult male rat DRG sensory neurons transduced with α9k1, and controls, with and without axotomy of the central branch. Expression of α9k1 without the central axotomy led to upregulation of a known PNS regeneration program, including many genes associated with peripheral nerve regeneration. Coupling α9k1 treatment with dorsal root axotomy led to extensive central axonal regeneration. In addition to the program upregulated by α9k1 expression, regeneration in the spinal cord led to expression of a distinctive CNS regeneration program, including genes associated with ubiquitination, autophagy, endoplasmic reticulum (ER), trafficking, and signaling. Pharmacological inhibition of these processes blocked the regeneration of axons from DRGs and human iPSC-derived sensory neurons, validating their causal contributions to sensory regeneration. This CNS regeneration-associated program showed little correlation with either embryonic development or PNS regeneration programs. Potential transcriptional drivers of this CNS program coupled to regeneration include Mef2a, Runx3, E2f4, and Yy1. Signaling from integrins primes sensory neurons for regeneration, but their axon growth in the CNS is associated with an additional distinctive program that differs from that involved in PNS regeneration.SIGNIFICANCE STATEMENT Restoration of neurologic function after spinal cord injury has yet to be achieved in human patients. To accomplish this, severed nerve fibers must be made to regenerate. Reconstruction of nerve pathways has not been possible, but recently, a method for stimulating long-distance axon regeneration of sensory fibers in rodents has been developed. This research uses profiling of messenger RNAs in the regenerating sensory neurons to discover which mechanisms are activated. This study shows that the regenerating neurons initiate a novel CNS regeneration program which includes molecular transport, autophagy, ubiquitination, and modulation of the endoplasmic reticulum (ER). The study identifies mechanisms that neurons need to activate to regenerate their nerve fibers.
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Axônios , Traumatismos da Medula Espinal , Ratos , Humanos , Masculino , Animais , Axônios/fisiologia , Integrinas/metabolismo , Regeneração Nervosa/fisiologia , Ratos Sprague-Dawley , Medula Espinal/metabolismo , Traumatismos da Medula Espinal/terapia , Traumatismos da Medula Espinal/metabolismo , Gânglios Espinais/metabolismo , Células Receptoras Sensoriais/fisiologiaRESUMO
Change history: In this Letter, the labels for splicing events A3SS and A5SS were swapped in column D of Supplementary Table 3a and b. This has been corrected online.
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Common genetic contributions to autism spectrum disorder (ASD) reside in risk gene variants that individually have minimal effect sizes. As environmental factors that perturb neurodevelopment also underlie idiopathic ASD, it is crucial to identify altered regulators that can orchestrate multiple ASD risk genes during neurodevelopment. Cytoplasmic polyadenylation element binding proteins 1-4 (CPEB1-4) regulate the translation of specific mRNAs by modulating their poly(A)-tails and thereby participate in embryonic development and synaptic plasticity. Here we find that CPEB4 binds transcripts of most high-confidence ASD risk genes. The brains of individuals with idiopathic ASD show imbalances in CPEB4 transcript isoforms that result from decreased inclusion of a neuron-specific microexon. In addition, 9% of the transcriptome shows reduced poly(A)-tail length. Notably, this percentage is much higher for high-confidence ASD risk genes, correlating with reduced expression of the protein products of ASD risk genes. An equivalent imbalance in CPEB4 transcript isoforms in mice mimics the changes in mRNA polyadenylation and protein expression of ASD risk genes and induces ASD-like neuroanatomical, electrophysiological and behavioural phenotypes. Together, these data identify CPEB4 as a regulator of ASD risk genes.
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Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/patologia , Predisposição Genética para Doença/genética , Poliadenilação , Splicing de RNA , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Éxons/genética , Feminino , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Fenótipo , Ligação Proteica , RNA Mensageiro/química , RNA Mensageiro/genética , TranscriptomaRESUMO
Despite numerous studies in the field of dementia and Alzheimer's disease (AD), a comprehensive understanding of this devastating disease remains elusive. Bulk transcriptomics have provided insights into the underlying genetic factors at a high level. Subsequent technological advancements have focused on single-cell omics, encompassing techniques such as single-cell RNA sequencing and epigenomics, enabling the capture of RNA transcripts and chromatin states at a single cell or nucleus resolution. Furthermore, the emergence of spatial omics has allowed the study of gene responses in the vicinity of amyloid beta plaques or across various brain regions. With the vast amount of data generated, utilizing gene regulatory networks to comprehensively study this disease has become essential. This review delves into some techniques employed in the field of AD, explores the discoveries made using these techniques, and provides insights into the future of the field.
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Doença de Alzheimer , Redes Reguladoras de Genes , Biologia de Sistemas , Doença de Alzheimer/genética , Humanos , Redes Reguladoras de Genes/genética , Epigenômica , Genômica , Encéfalo/metabolismo , MultiômicaRESUMO
INTRODUCTION: Alzheimer's disease (AD) is a neurodegenerative disorder with multifactorial etiology, including genetic factors that play a significant role in disease risk and resilience. However, the role of genetic diversity in preclinical AD studies has received limited attention. METHODS: We crossed five Collaborative Cross strains with 5xFAD C57BL/6J female mice to generate F1 mice with and without the 5xFAD transgene. Amyloid plaque pathology, microglial and astrocytic responses, neurofilament light chain levels, and gene expression were assessed at various ages. RESULTS: Genetic diversity significantly impacts AD-related pathology. Hybrid strains showed resistance to amyloid plaque formation and neuronal damage. Transcriptome diversity was maintained across ages and sexes, with observable strain-specific variations in AD-related phenotypes. Comparative gene expression analysis indicated correlations between mouse strains and human AD. DISCUSSION: Increasing genetic diversity promotes resilience to AD-related pathogenesis, relative to an inbred C57BL/6J background, reinforcing the importance of genetic diversity in uncovering resilience in the development of AD. HIGHLIGHTS: Genetic diversity's impact on AD in mice was explored. Diverse F1 mouse strains were used for AD study, via the Collaborative Cross. Strain-specific variations in AD pathology, glia, and transcription were found. Strains resilient to plaque formation and plasma neurofilament light chain (NfL) increases were identified. Correlations with human AD transcriptomics were observed.
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Doença de Alzheimer , Resiliência Psicológica , Camundongos , Humanos , Feminino , Animais , Doença de Alzheimer/patologia , Placa Amiloide/patologia , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Variação Genética/genética , Modelos Animais de Doenças , Camundongos Transgênicos , Peptídeos beta-Amiloides/metabolismoRESUMO
INTRODUCTION: The BIN1 coding variant rs138047593 (K358R) is linked to Late-Onset Alzheimer's Disease (LOAD) via targeted exome sequencing. METHODS: To elucidate the functional consequences of this rare coding variant on brain amyloidosis and neuroinflammation, we generated BIN1K358R knock-in mice using CRISPR/Cas9 technology. These mice were subsequently bred with 5xFAD transgenic mice, which serve as a model for Alzheimer's pathology. RESULTS: The presence of the BIN1K358R variant leads to increased cerebral amyloid deposition, with a dampened response of astrocytes and oligodendrocytes, but not microglia, at both the cellular and transcriptional levels. This correlates with decreased neurofilament light chain in both plasma and brain tissue. Synaptic densities are significantly increased in both wild-type and 5xFAD backgrounds homozygous for the BIN1K358R variant. DISCUSSION: The BIN1 K358R variant modulates amyloid pathology in 5xFAD mice, attenuates the astrocytic and oligodendrocytic responses to amyloid plaques, decreases damage markers, and elevates synaptic densities. HIGHLIGHTS: BIN1 rs138047593 (K358R) coding variant is associated with increased risk of LOAD. BIN1 K358R variant increases amyloid plaque load in 12-month-old 5xFAD mice. BIN1 K358R variant dampens astrocytic and oligodendrocytic response to plaques. BIN1 K358R variant decreases neuronal damage in 5xFAD mice. BIN1 K358R upregulates synaptic densities and modulates synaptic transmission.
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Doença de Alzheimer , Animais , Camundongos , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides , Modelos Animais de Doenças , Camundongos Transgênicos , Neuroglia/patologia , Placa Amiloide/patologia , HumanosRESUMO
Stress may promote emotional and cognitive disturbances, which differ by sex. Adverse outcomes, including memory disturbances, are typically observed following chronic stress, but are now being recognized also after short events, including mass shootings, assault, or natural disasters, events that consist of concurrent multiple acute stresses (MAS). Prior work has established profound and enduring effects of MAS on memory in males. Here we examined the effects of MAS on female mice and probed the role of hormonal fluctuations during the estrous cycle on MAS-induced memory problems and the underlying brain network and cellular mechanisms. Female mice were impacted by MAS in an estrous cycle-dependent manner: MAS impaired hippocampus-dependent spatial memory in early-proestrous mice, characterized by high levels of estradiol, whereas memory of mice stressed during estrus (low estradiol) was spared. As spatial memory requires an intact dorsal hippocampal CA1, we examined synaptic integrity in mice stressed at different cycle phases and found a congruence of dendritic spine density and spatial memory deficits, with reduced spine density only in mice stressed during high estradiol cycle phases. Assessing MAS-induced activation of brain networks interconnected with hippocampus, we identified differential estrous cycle-dependent activation of memory- and stress-related regions, including the amygdala. Network analyses of the cross-correlation of fos expression among these regions uncovered functional connectivity that differentiated impaired mice from those not impaired by MAS. In conclusion, the estrous cycle modulates the impact of MAS on spatial memory, and fluctuating physiological levels of sex hormones may contribute to this effect.SIGNIFICANCE STATEMENT: Effects of stress on brain functions, including memory, are profound and sex-dependent. Acute stressors occurring simultaneously result in spatial memory impairments in males, but effects on females are unknown. Here we identified estrous cycle-dependent effects of such stresses on memory in females. Surprisingly, females with higher physiological estradiol experienced stress-induced memory impairment and a loss of underlying synapses. Memory- and stress-responsive brain regions interconnected with hippocampus were differentially activated across high and low estradiol mice, and predicted memory impairment. Thus, at functional, network, and cellular levels, physiological estradiol influences the effects of stress on memory in females, providing insight into mechanisms of prominent sex differences in stress-related memory disorders, such as post-traumatic stress disorder.
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Estrogênios , Transtornos da Memória/fisiopatologia , Transtornos da Memória/psicologia , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia , Animais , Encéfalo/fisiopatologia , Região CA1 Hipocampal/fisiopatologia , Espinhas Dendríticas , Ciclo Estral , Estro , Feminino , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Rede Nervosa/fisiopatologia , Proteínas Proto-Oncogênicas c-fos/genética , Memória Espacial , Útero/inervação , Útero/fisiopatologiaRESUMO
Alzheimer's disease (AD) is a devastating neurological disorder characterized by changes in cell-type proportions and consequently marked alterations of the transcriptome. Here we use a data-driven systems biology meta-analytical approach across three human AD cohorts, encompassing six cortical brain regions, and integrate with multi-scale datasets comprising of DNA methylation, histone acetylation, transcriptome- and genome-wide association studies and quantitative trait loci to further characterize the genetic architecture of AD. We perform co-expression network analysis across more than 1200 human brain samples, identifying robust AD-associated dysregulation of the transcriptome, unaltered in normal human aging. We assess the cell-type specificity of AD gene co-expression changes and estimate cell-type proportion changes in human AD by integrating co-expression modules with single-cell transcriptome data generated from 27 321 nuclei from human postmortem prefrontal cortical tissue. We also show that genetic variants of AD are enriched in a microglial AD-associated module and identify key transcription factors regulating co-expressed modules. Additionally, we validate our results in multiple published human AD gene expression datasets, which can be easily accessed using our online resource (https://swaruplab.bio.uci.edu/consensusAD).
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Doença de Alzheimer/genética , Genômica , Microglia/metabolismo , Transcriptoma/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Envelhecimento/patologia , Doença de Alzheimer/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Biologia Computacional , Metilação de DNA/genética , Perfilação da Expressão Gênica , Redes Reguladoras de Genes/genética , Estudo de Associação Genômica Ampla , Humanos , Microglia/patologia , Pessoa de Meia-Idade , Adulto JovemRESUMO
Autism spectrum disorder (ASD) involves substantial genetic contributions. These contributions are profoundly heterogeneous but may converge on common pathways that are not yet well understood. Here, through post-mortem genome-wide transcriptome analysis of the largest cohort of samples analysed so far, to our knowledge, we interrogate the noncoding transcriptome, alternative splicing, and upstream molecular regulators to broaden our understanding of molecular convergence in ASD. Our analysis reveals ASD-associated dysregulation of primate-specific long noncoding RNAs (lncRNAs), downregulation of the alternative splicing of activity-dependent neuron-specific exons, and attenuation of normal differences in gene expression between the frontal and temporal lobes. Our data suggest that SOX5, a transcription factor involved in neuron fate specification, contributes to this reduction in regional differences. We further demonstrate that a genetically defined subtype of ASD, chromosome 15q11.2-13.1 duplication syndrome (dup15q), shares the core transcriptomic signature observed in idiopathic ASD. Co-expression network analysis reveals that individuals with ASD show age-related changes in the trajectory of microglial and synaptic function over the first two decades, and suggests that genetic risk for ASD may influence changes in regional cortical gene expression. Our findings illustrate how diverse genetic perturbations can lead to phenotypic convergence at multiple biological levels in a complex neuropsychiatric disorder.
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Processamento Alternativo/genética , Transtorno do Espectro Autista/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Genoma Humano/genética , RNA Longo não Codificante/genética , Animais , Autopsia , Estudos de Casos e Controles , Aberrações Cromossômicas , Cromossomos Humanos Par 15/genética , Éxons/genética , Lobo Frontal/metabolismo , Humanos , Deficiência Intelectual/genética , Neurônios/metabolismo , Primatas/genética , Fatores de Transcrição SOXD/metabolismo , Especificidade da Espécie , Lobo Temporal/metabolismo , Transcriptoma/genéticaRESUMO
Over the years, genetic studies have identified multiple genetic risk variants associated with neurodegenerative disorders and helped reveal new biological pathways and genes of interest. However, genetic risk variants commonly reside in non-coding regions and may regulate distant genes rather than the nearest gene, as well as a gene's interaction partners in biological networks. Systems biology and functional genomics approaches provide the framework to unravel the functional significance of genetic risk variants in disease. In this review, we summarize the genetic and transcriptomic studies of Alzheimer's disease and related tauopathies and focus on the advantages of performing systems-level analyses to interrogate the biological pathways underlying neurodegeneration. Finally, we highlight new avenues of multi-omics analysis with single-cell approaches, which provide unparalleled opportunities to systematically explore cellular heterogeneity, and present an example of how to integrate publicly available single-cell datasets. Systems-level analysis has illuminated the function of many disease risk genes, but much work remains to study tauopathies and to understand spatiotemporal gene expression changes of specific cell types.
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Doença de Alzheimer/metabolismo , Biologia de Sistemas , Tauopatias/metabolismo , Doença de Alzheimer/genética , Genômica , Humanos , Tauopatias/genética , TranscriptomaRESUMO
BACKGROUND: Microglia, the primary resident myeloid cells of the brain, play critical roles in immune defense by maintaining tissue homeostasis and responding to injury or disease. However, microglial activation and dysfunction has been implicated in a number of central nervous system (CNS) disorders, thus developing tools to manipulate and replace these myeloid cells in the CNS is of therapeutic interest. METHODS: Using whole body irradiation, bone marrow transplant, and colony-stimulating factor 1 receptor inhibition, we achieve long-term and brain-wide (~ 80%) engraftment and colonization of peripheral bone marrow-derived myeloid cells (i.e., monocytes) in the brain parenchyma and evaluated the long-term effects of their colonization in the CNS. RESULTS: Here, we identify a monocyte signature that includes an upregulation in Ccr1, Ms4a6b, Ms4a6c, Ms4a7, Apobec1, Lyz2, Mrc1, Tmem221, Tlr8, Lilrb4a, Msr1, Nnt, and Wdfy1 and a downregulation of Siglech, Slc2a5, and Ccl21a/b. We demonstrate that irradiation and long-term (~ 6 months) engraftment of the CNS by monocytes induces brain region-dependent alterations in transcription profiles, astrocytes, neuronal structures, including synaptic components, and cognition. Although our results show that microglial replacement with peripherally derived myeloid cells is feasible and that irradiation-induced changes can be reversed by the replacement of microglia with monocytes in the hippocampus, we also observe that brain-wide engraftment of peripheral myeloid cells (relying on irradiation) can result in cognitive and synaptic deficits. CONCLUSIONS: These findings provide insight into better understanding the role and complexity of myeloid cells in the brain, including their regulation of other CNS cells and functional outcomes.
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Células da Medula Óssea/imunologia , Transplante de Medula Óssea/métodos , Encéfalo/citologia , Encéfalo/imunologia , Células Mieloides/imunologia , Animais , Medula Óssea/imunologia , Medula Óssea/efeitos da radiação , Encéfalo/efeitos da radiação , Sistema Nervoso Central/citologia , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/fisiologia , Monócitos/efeitos da radiação , Células Mieloides/efeitos da radiação , Transcrição Gênica/fisiologia , Transcrição Gênica/efeitos da radiaçãoRESUMO
BACKGROUND: Williams syndrome (WS) is a neurodevelopmental disorder that has been attributed to heterozygous deletions in chromosome 7q11.23 and exhibits a variety of physical, cognitive, and behavioral features. However, the genetic basis of this phenotypic variability is unclear. In this study, we identified genetic clues underlying these complex phenotypes. METHODS: Neurobehavioral function was assessed in WS patients and healthy controls. Total RNA was extracted from peripheral blood and subjected to microarray analysis, RNA-sequencing, and qRT-PCR. Weighted gene co-expression network analysis was performed to identify specific alterations related to intermediate disease phenotypes. To functionally interpret each WS-related module, gene ontology and disease-related gene enrichment were examined. We also investigated the micro (mi)RNA expression profiles and miRNA co-expression networks to better explain the regulation of the transcriptome in WS. RESULTS: Our analysis identified four significant co-expression modules related to intermediate WS phenotypes. Notably, the three upregulated WS-related modules were composed exclusively of genes located outside the 7q11.23 region. They were significantly enriched in genes related to B-cell activation, RNA processing, and RNA transport. BCL11A, which is known for its association with speech disorders and intellectual disabilities, was identified as one of the hub genes in the top WS-related module. Finally, these key upregulated mRNA co-expression modules appear to be inversely correlated with a specific downregulated WS-related miRNA co-expression module. CONCLUSIONS: Dysregulation of the mRNA/miRNA network involving genes outside of the 7q11.23 region is likely related to the complex phenotypes observed in WS patients.
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Transtorno do Espectro Autista/genética , Perfilação da Expressão Gênica , Expressão Gênica/genética , Síndrome de Williams/genética , Criança , Cromossomos Humanos Par 7/genética , Humanos , MicroRNAs/genética , RNA Mensageiro/genéticaRESUMO
INTRODUCTION: Comparative transcriptome analyses in Alzheimer's disease (AD) and other neurodegenerative proteinopathies can uncover both shared and distinct disease pathways. METHODS: We analyzed 940 brain transcriptomes including patients with AD, progressive supranuclear palsy (PSP; a primary tauopathy), and control subjects. RESULTS: We identified transcriptional coexpression networks implicated in myelination, which were lower in PSP temporal cortex (TCX) compared with AD. Some of these associations were retained even after adjustments for brain cell population changes. These TCX myelination network structures were preserved in cerebellum but they were not differentially expressed in cerebellum between AD and PSP. Myelination networks were downregulated in both AD and PSP, when compared with control TCX samples. DISCUSSION: Downregulation of myelination networks may underlie both PSP and AD pathophysiology, but may be more pronounced in PSP. These data also highlight conservation of transcriptional networks across brain regions and the influence of cell type changes on these networks.
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Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Paralisia Supranuclear Progressiva/metabolismo , Transcriptoma , Doença de Alzheimer/genética , Estudos de Coortes , Biologia Computacional , Feminino , Regulação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Masculino , Bainha de Mielina/metabolismo , Neurônios/metabolismo , Paralisia Supranuclear Progressiva/genéticaRESUMO
Japanese encephalitis virus (JEV), a member of the Flaviviridae family, is a leading cause of viral encephalitis in humans. Survivors of this infection often develop lifelong neurological sequelae. Short-chain fatty acids (SCFAs) produced in the gut are vital mediators of the gut-brain axis. We aimed to study microRNA-based mechanisms of SCFAs in an in vitro model of JEV infection. N9 microglial cells were pretreated with SCFA cocktail before JEV infection. Cytokine bead analysis, immunoblotting, and PCR were performed to analyze relevant inflammatory markers. microRNA sequencing was performed using Illumina Hiseq, and bioinformatics tools were used for differentially expressed (DE) miRNAs and weighted gene co-expression network analysis (WGCNA). microRNA mimic/inhibitor experiments and luciferase assay were performed to study miRNA-target interaction. A significant reduction in monocyte chemoattractant protein (MCP1) and tumor necrosis factor alpha (TNFα) along with reduced expression of phospho-nuclear factor kappa B (phospho-NF-κB) was observed in SCFA conditions. Significant attenuation of histone deacetylase activity and protein expression was recorded. miRNA sequencing revealed 160 DE miRNAs in SCFA + JEV-treated cells at 6 h post-infection. WGCNA revealed miR-200a-3p, a hub miRNA significantly upregulated in SCFA conditions. Transcription factor ZBTB20 was bioinformatically predicted and validated as a gene target for miR-200a-3p. Further miRNA mimic/inhibitor assay demonstrated that miR-200-3p regulated ZBTB20 along with Iκßα that possibly dampened NF-κB signal activation downstream. IMPORTANCE: The gut-brain axis plays a pivotal role in the physiological state of an organism. Gut microbiota-derived metabolites are known to play a role in brain disorders including neuroviral infections. Short-chain fatty acids (SCFAs) appear to quench inflammatory markers in Japanese encephalitis virus-infected microglial cells in vitro. Mechanistically, we demonstrate the interaction between miR-200a-3p and ZBTB20 in regulating the canonical nuclear factor kappa B (NF-κB) signaling pathway via transcriptional regulation of Iκßα. Findings of this study pave the way to a better understanding of SCFA mechanisms that can be used to develop strategies against viral neuroinflammation.
Assuntos
Vírus da Encefalite Japonesa (Espécie) , Ácidos Graxos Voláteis , Inflamação , MicroRNAs , Microglia , MicroRNAs/genética , MicroRNAs/metabolismo , Vírus da Encefalite Japonesa (Espécie)/fisiologia , Vírus da Encefalite Japonesa (Espécie)/genética , Microglia/virologia , Microglia/metabolismo , Ácidos Graxos Voláteis/metabolismo , Ácidos Graxos Voláteis/farmacologia , Camundongos , Animais , Inflamação/genética , Inflamação/virologia , Encefalite Japonesa/virologia , Encefalite Japonesa/genética , Encefalite Japonesa/metabolismo , Linhagem Celular , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Inibidor de NF-kappaB alfa/metabolismo , Inibidor de NF-kappaB alfa/genética , NF-kappa B/metabolismo , NF-kappa B/genética , Transdução de Sinais , HumanosRESUMO
Central nervous system (CNS) lesions become surrounded by neuroprotective borders of newly proliferated reactive astrocytes; however, fundamental features of these cells are poorly understood. Here we show that following spinal cord injury or stroke, 90% and 10% of border-forming astrocytes derive, respectively, from proliferating local astrocytes and oligodendrocyte progenitor cells in adult mice of both sexes. Temporal transcriptome analysis, single-nucleus RNA sequencing and immunohistochemistry show that after focal CNS injury, local mature astrocytes dedifferentiate, proliferate and become transcriptionally reprogrammed to permanently altered new states, with persisting downregulation of molecules associated with astrocyte-neuron interactions and upregulation of molecules associated with wound healing, microbial defense and interactions with stromal and immune cells. These wound repair astrocytes share morphologic and transcriptional features with perimeningeal limitans astrocytes and are the predominant source of neuroprotective borders that re-establish CNS integrity around lesions by separating neural parenchyma from stromal and immune cells as occurs throughout the healthy CNS.