RESUMO
The optimization of brain circuit connectivity based on initial environmental input occurs during critical periods characterized by sensory experience-dependent, temporally restricted, and transiently reversible synapse elimination. This precise, targeted synaptic pruning mechanism is mediated by glial phagocytosis. Serotonin signaling has prominent, foundational roles in the brain, but functions in glia, or in experience-dependent brain circuit synaptic connectivity remodeling, have been relatively unknown. Here, we discover that serotonergic signaling between glia is essential for olfactory experience-dependent synaptic glomerulus pruning restricted to a well-defined Drosophila critical period. We find that experience-dependent serotonin signaling is restricted to the critical period, with both (1) serotonin production and (2) 5-HT2A receptors specifically in glia, but not neurons, absolutely required for targeted synaptic glomerulus pruning. We discover that glial 5-HT2A receptor signaling limits the experience-dependent synaptic connectivity pruning in the critical period and that conditional reexpression of 5-HT2A receptors within adult glia reestablishes "critical period-like" experience-dependent synaptic glomerulus pruning at maturity. These results reveal an essential requirement for glial serotonergic signaling mediated by 5-HT2A receptors for experience-dependent synapse elimination.
Assuntos
Neuroglia , Receptor 5-HT2A de Serotonina , Serotonina , Transdução de Sinais , Sinapses , Animais , Neuroglia/metabolismo , Sinapses/metabolismo , Sinapses/fisiologia , Serotonina/metabolismo , Receptor 5-HT2A de Serotonina/metabolismo , Plasticidade Neuronal/fisiologia , Drosophila melanogaster/metabolismo , Drosophila/metabolismoRESUMO
Progressive supranuclear palsy (PSP), a rare Parkinsonian disorder, is characterized by problems with movement, balance, and cognition. PSP differs from Alzheimer's disease (AD) and other diseases, displaying abnormal microtubule-associated protein tau by both neuronal and glial cell pathologies. Genetic contributors may mediate these differences; however, the genetics of PSP remain underexplored. Here we conduct the largest genome-wide association study (GWAS) of PSP which includes 2779 cases (2595 neuropathologically-confirmed) and 5584 controls and identify six independent PSP susceptibility loci with genome-wide significant (P < 5 × 10-8) associations, including five known (MAPT, MOBP, STX6, RUNX2, SLCO1A2) and one novel locus (C4A). Integration with cell type-specific epigenomic annotations reveal an oligodendrocytic signature that might distinguish PSP from AD and Parkinson's disease in subsequent studies. Candidate PSP risk gene prioritization using expression quantitative trait loci (eQTLs) identifies oligodendrocyte-specific effects on gene expression in half of the genome-wide significant loci, and an association with C4A expression in brain tissue, which may be driven by increased C4A copy number. Finally, histological studies demonstrate tau aggregates in oligodendrocytes that colocalize with C4 (complement) deposition. Integrating GWAS with functional studies, epigenomic and eQTL analyses, we identify potential causal roles for variation in MOBP, STX6, RUNX2, SLCO1A2, and C4A in PSP pathogenesis.
Assuntos
Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Locos de Características Quantitativas , Paralisia Supranuclear Progressiva , Proteínas tau , Humanos , Paralisia Supranuclear Progressiva/genética , Paralisia Supranuclear Progressiva/patologia , Paralisia Supranuclear Progressiva/metabolismo , Idoso , Masculino , Feminino , Proteínas tau/genética , Proteínas tau/metabolismo , Transcriptoma , Polimorfismo de Nucleotídeo Único , Neuroglia/metabolismo , Neuroglia/patologia , Idoso de 80 Anos ou mais , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Pessoa de Meia-Idade , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Doença de Alzheimer/metabolismo , Estudos de Casos e Controles , Proteínas da MielinaRESUMO
Glioblastoma remains one of the deadliest brain malignancies. First-line therapy consists of maximal surgical tumor resection, accompanied by chemotherapy and radiotherapy. Malignant cells escape surgical resection by migrating into the surrounding healthy brain tissue, where they give rise to the recurrent tumor. Based on gene expression, tumor cores can be subtyped into mesenchymal, proneural, and classical tumors, each being associated with differences in genetic alterations and cellular composition. In contrast, the adjacent brain parenchyma where infiltrating malignant cells escape surgical resection is less characterized in patients. Using spatial transcriptomics (n = 11), we show that malignant cells within proneural or mesenchymal tumor cores display spatially organized differences in gene expression, although such differences decrease within the infiltrated brain tissue. Malignant cells residing in infiltrated brain tissue have increased expression of genes related to neurodevelopmental pathways and glial cell differentiation. Our findings provide an updated view of the spatial landscape of glioblastomas and further our understanding of the malignant cells that infiltrate the healthy brain, providing new avenues for the targeted therapy of these cells after surgical resection.
Assuntos
Neoplasias Encefálicas , Encéfalo , Regulação Neoplásica da Expressão Gênica , Glioblastoma , Receptores Notch , Transdução de Sinais , Humanos , Glioblastoma/genética , Glioblastoma/patologia , Glioblastoma/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/metabolismo , Receptores Notch/metabolismo , Receptores Notch/genética , Encéfalo/metabolismo , Encéfalo/patologia , Transcriptoma , Sinapses/metabolismo , Masculino , Feminino , Linhagem Celular Tumoral , Neuroglia/metabolismo , Neuroglia/patologia , Diferenciação Celular/genéticaRESUMO
Stem cell niche is critical for regulating the behavior of stem cells. Drosophila neural stem cells (Neuroblasts, NBs) are encased by glial niche cells closely, but it still remains unclear whether glial niche cells can regulate the self-renewal and differentiation of NBs. Here, we show that ferritin produced by glia, cooperates with Zip13 to transport iron into NBs for the energy production, which is essential to the self-renewal and proliferation of NBs. The knockdown of glial ferritin encoding genes causes energy shortage in NBs via downregulating aconitase activity and NAD+ level, which leads to the low proliferation and premature differentiation of NBs mediated by Prospero entering nuclei. More importantly, ferritin is a potential target for tumor suppression. In addition, the level of glial ferritin production is affected by the status of NBs, establishing a bicellular iron homeostasis. In this study, we demonstrate that glial cells are indispensable to maintain the self-renewal of NBs, unveiling a novel role of the NB glial niche during brain development.
Iron is an essential nutrient for almost all living organisms. For example, iron contributes to the replication of DNA, the generation of energy inside cells, and the transport of oxygen around the body. Iron deficiency is the most common of all nutrient deficiencies, affecting over 40% of children worldwide. This can lead to anemia and also impair how the brain and nervous system develop, potentially resulting in long-lasting cognitive damage, even after the deficiency has been treated. It is poorly understood how iron contributes to the development of the brain and nervous system. In particular, whether and how it supports nerve stem cells (or NSCs for short) which give rise to the various neural types in the mature brain. To investigate, Ma et al. experimentally reduced the levels of ferritin (a protein which stores iron) in the developing brains of fruit fly larvae. This reduction in ferritin led to lower numbers of NSCs and a smaller brain. Unexpectedly, this effect was largest when ferritin levels were reduced in glial cells which support and send signals to NSCs, rather than in the stem cells themselves. Ma et al. then used fluorescence microscopy to confirm that glial cells make and contain a lot of ferritin which can be transported to NSCs. Adding iron supplements to the diet of flies lacking ferritin did not lead to normal numbers of stem cells in the brains of the developing fruit flies, whereas adding compounds that reduce the amount of iron led to lower numbers of stem cells. Together, this suggests that ferritin transports iron from glial cells to the NSCs. Without ferritin and iron, the NSCs could not produce enough energy to divide and make new stem cells. This caused the NSCs to lose the characteristics of stem cells and prematurely turn into other types of neurons or glial cells. Together, these findings show that when iron cannot move from glial cells to NSCs this leads to defects in brain development. Future experiments will have to test whether a similar transport of iron from supporting cells to NSCs also occurs in the developing brains of mammals, and whether this mechanism applies to stem cells in other parts of the body.
Assuntos
Proteínas de Drosophila , Ferritinas , Ferro , Células-Tronco Neurais , Neuroglia , Animais , Células-Tronco Neurais/metabolismo , Neuroglia/metabolismo , Ferro/metabolismo , Ferritinas/metabolismo , Ferritinas/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Drosophila/metabolismo , Proliferação de Células , Diferenciação Celular , Drosophila melanogaster/metabolismo , Drosophila melanogaster/genética , Autorrenovação CelularRESUMO
Cryptococcus neoformans (Cn) is an opportunistic encapsulated fungal pathogen that causes life-threatening meningoencephalitis in immunosuppressed individuals. Since IL-6 is important for blood-brain barrier support and its deficiency has been shown to facilitate Cn brain invasion, we investigated the impact of IL-6 on systemic Cn infection in vivo, focusing on central nervous system (CNS) colonization and glial responses, specifically microglia and astrocytes. IL-6 knock-out (IL-6-/-) mice showed faster mortality than C57BL/6 (Wild-type) and IL-6-/- supplemented with recombinant IL-6 (rIL-6; 40 pg/g/day) mice. Despite showing early lung inflammation but no major histological differences in pulmonary cryptococcosis progression among the experimental groups, IL-6-/- mice had significantly higher blood and brain tissue fungal burden at 7-days post infection. Exposure of cryptococci to rIL-6 in vitro increased capsule growth. In addition, IL-6-/- brains were characterized by an increased dystrophic microglia number during Cn infection, which are associated with neurodegeneration and senescence. In contrast, the brains of IL-6-producing or -supplemented mice displayed high numbers of activated and phagocytic microglia, which are related to a stronger anti-cryptococcal response or tissue repair. Likewise, culture of rIL-6 with microglia-like cells promoted high fungal phagocytosis and killing, whereas IL-6 silencing in microglia decreased fungal phagocytosis. Lastly, astrogliosis was high and moderate in infected brains removed from Wild-type and IL-6-/- supplemented with rIL-6 animals, respectively, while minimal astrogliosis was observed in IL-6-/- tissue, highlighting the potential of astrocytes in containing and combating cryptococcal infection. Our findings suggest a critical role for IL-6 in Cn CNS dissemination, neurocryptococcosis development, and host defense.
Assuntos
Criptococose , Cryptococcus neoformans , Interleucina-6 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neuroglia , Animais , Camundongos , Interleucina-6/metabolismo , Neuroglia/patologia , Neuroglia/metabolismo , Neuroglia/microbiologia , Criptococose/patologia , Criptococose/imunologia , Criptococose/microbiologia , Encéfalo/patologia , Encéfalo/metabolismoRESUMO
Leptin is a hormone produced by the small intestines and adipose tissue that promotes feelings of satiety. Leptin receptors (LepRs) are highly expressed in the hypothalamus, enabling central neural control of hunger. Interestingly, LepRs are also expressed in several other regions of the body and brain, notably in the cerebral cortex and hippocampus. These brain regions mediate higher-order sensory, motor, cognitive, and memory functions, which can be profoundly altered during periods of hunger and satiety. However, LepR expression in these regions has not been fully characterized on a cell-type-specific basis, which is necessary to begin assessing their potential functional impact. Consequently, we examined LepR expression on neurons and glia in the forebrain using a LepR-Cre transgenic mouse model. LepR-positive cells were identified using a 'floxed' viral cell-filling approach and co-labeling immunohistochemically for cell-type-specific markers, i.e., NeuN, VGlut2, GAD67, parvalbumin, somatostatin, 5-HT3R, WFA, S100ß, and GFAP. In the cortex, LepR-positive cells were localized to lower layers (primarily layer 6) and exhibited non-pyramidal cellular morphologies. The majority of cortical LepR-positive cells were neurons, while the remainder were identified primarily as astrocytes or other glial cells. The majority of cortical LepR-positive neurons co-expressed parvalbumin, while none expressed somatostatin or 5-HT3R. In contrast, all hippocampal LepR-positive cells were neuronal, with none co-expressing GFAP. These data suggest that leptin can potentially influence neural processing in forebrain regions associated with sensation and limbic-related functions.
Assuntos
Camundongos Transgênicos , Neurônios , Prosencéfalo , Receptores para Leptina , Animais , Receptores para Leptina/metabolismo , Receptores para Leptina/genética , Camundongos , Neurônios/metabolismo , Prosencéfalo/metabolismo , Neuroglia/metabolismo , Masculino , Astrócitos/metabolismoRESUMO
The primary supporting cell of the retina is the retinal glial Müller cell. They cover the entire retinal surface and are in close proximity to both the retinal blood vessels and the retinal neurons. Because of their growth, Müller cells perform several crucial tasks in a healthy retina, including the uptake and recycling of neurotransmitters, retinoic acid compounds, and ions (like potassium K+). In addition to regulating blood flow and maintaining the blood-retinal barrier, they also regulate the metabolism and the supply of nutrients to the retina. An established procedure for isolating primary mouse Müller cells is presented in this manuscript. To better understand the underlying molecular processes involved in the various mouse models of ocular disorders, Müller cell isolation is an excellent approach. This manuscript outlines a detailed procedure for Müller cell isolation from mice. From enucleation to seeding, the entire process lasts about a few hours. For 5-7 days after seeding, the media shouldn't be changed in order to allow the isolated cells to grow unhindered. Cell characterization using morphology and distinct immunofluorescent markers comes next in the process. Maximum passages for cells are 3-4 times.
Assuntos
Células Ependimogliais , Retina , Animais , Camundongos , Células Ependimogliais/citologia , Células Ependimogliais/metabolismo , Retina/citologia , Técnicas Citológicas/métodos , Neuroglia/citologia , Neuroglia/metabolismoRESUMO
Two-dimensional neuronal cultures have a limited ability to recapitulate the in vivo environment of the brain. Here, we introduce a three-dimensional in vitro model for human glia-to-neuron conversion, surpassing the spatial and temporal constrains of two-dimensional cultures. Focused on direct conversion to induced dopamine neurons (iDANs) relevant to Parkinson disease, the model generates functionally mature iDANs in 2 weeks and allows long-term survival. As proof of concept, we use single-nucleus RNA sequencing and molecular lineage tracing during iDAN generation and find that all glial subtypes generate neurons and that conversion relies on the coordinated expression of three neural conversion factors. We also show the formation of mature and functional iDANs over time. The model facilitates molecular investigations of the conversion process to enhance understanding of conversion outcomes and offers a system for in vitro reprogramming studies aimed at advancing alternative therapeutic strategies in the diseased brain.
Assuntos
Neurônios Dopaminérgicos , Neuroglia , Humanos , Neurônios Dopaminérgicos/metabolismo , Neuroglia/metabolismo , Diferenciação Celular , Células CultivadasRESUMO
Cuprous copper [Cu(I)] is an essential cofactor for enzymes that support many fundamental cellular functions including mitochondrial respiration and suppression of oxidative stress. Neurons are particularly reliant on mitochondrial production of ATP, with many neurodegenerative diseases, including Parkinson's disease, associated with diminished mitochondrial function. The gene MBLAC1 encodes a ribonuclease that targets pre-mRNA of replication-dependent histones, proteins recently found in yeast to reduce Cu(II) to Cu(I), and when mutated disrupt ATP production, elevates oxidative stress, and severely impacts cell growth. Whether this process supports neuronal and/or systemic physiology in higher eukaryotes is unknown. Previously, we identified swip-10, the putative Caenorhabditis elegans ortholog of MBLAC1, establishing a role for glial swip-10 in limiting dopamine (DA) neuron excitability and sustaining DA neuron viability. Here, we provide evidence from computational modeling that SWIP-10 protein structure mirrors that of MBLAC1 and locates a loss of function coding mutation at a site expected to disrupt histone RNA hydrolysis. Moreover, we find through genetic, biochemical, and pharmacological studies that deletion of swip-10 in worms negatively impacts systemic Cu(I) levels, leading to deficits in mitochondrial respiration and ATP production, increased oxidative stress, and neurodegeneration. These phenotypes can be offset in swip-10 mutants by the Cu(I) enhancing molecule elesclomol and through glial expression of wildtype swip-10. Together, these studies reveal a glial-expressed pathway that supports systemic mitochondrial function and neuronal health via regulation of Cu(I) homeostasis, a mechanism that may lend itself to therapeutic strategies to treat devastating neurodegenerative diseases.
Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Cobre , Homeostase , Mitocôndrias , Neuroglia , Estresse Oxidativo , Animais , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/genética , Mitocôndrias/metabolismo , Cobre/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Neuroglia/metabolismo , Neurônios Dopaminérgicos/metabolismo , Sobrevivência Celular , Neurônios/metabolismoRESUMO
Intercellular adhesion molecule 1 (ICAM-1/CD54), a transmembrane glycoprotein, has been considered as one of the most important adhesion molecules during leukocyte recruitment. It is encoded by the ICAM1 gene and plays a central role in inflammation. Its crucial role in many inflammatory diseases such as ulcerative colitis and rheumatoid arthritis are well established. Given that neuroinflammation, underscored by microglial activation, is a key element in neurodegenerative diseases such as Parkinson's disease (PD), we investigated whether ICAM-1 has a role in this progressive neurological condition and, if so, to elucidate the underpinning mechanisms. Specifically, we were interested in the potential interaction between ICAM-1, glial cells, and ferroptosis, an iron-dependent form of cell death that has recently been implicated in PD. We conclude that there exist direct and indirect (via glial cells and T cells) influences of ICAM-1 on ferroptosis and that further elucidation of these interactions can suggest novel intervention for this devastating disease.
Assuntos
Ferroptose , Inflamação , Molécula 1 de Adesão Intercelular , Doença de Parkinson , Ferroptose/genética , Molécula 1 de Adesão Intercelular/metabolismo , Doença de Parkinson/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/patologia , Humanos , Animais , Inflamação/patologia , Inflamação/metabolismo , Neuroglia/metabolismo , Neuroglia/patologia , Ferro/metabolismoRESUMO
The median eminence (ME), located at the base of the hypothalamus, is an essential centre of information exchange between the brain and the pituitary. We and others previously showed that mutations and duplications affecting the transcription factor SOX3/Sox3 result in hypopituitarism, and this is likely of hypothalamic origin. We demonstrate here that the absence of Sox3 predominantly affects the ME with phenotypes that first occur in juvenile animals, despite the embryonic onset of SOX3 expression. In the pituitary, reduction in hormone levels correlates with a lack of endocrine cell maturation. In parallel, ME NG2-glia renewal and oligodendrocytic differentiation potential are affected. We further show that low-dose aspirin treatment, which is known to affect NG2-glia, or changes in gut microbiota, rescue both proliferative defects and hypopituitarism in Sox3 mutants. Our study highlights a central role of NG2-glia for ME function during a transitional period of post-natal development and indicates their sensitivity to extrinsic signals.
Assuntos
Aspirina , Microbioma Gastrointestinal , Hipopituitarismo , Eminência Mediana , Neuroglia , Animais , Hipopituitarismo/genética , Aspirina/farmacologia , Camundongos , Microbioma Gastrointestinal/genética , Eminência Mediana/metabolismo , Neuroglia/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Diferenciação Celular , Hipófise/metabolismo , Camundongos Knockout , MasculinoRESUMO
Infrared neural stimulation (INS) emerges as a promising tool for stimulating the nervous system by its high spatial precision and absence of the use of exogenous agents into the tissue, which led to the first successful proof of concept in human brain. While neural networks have been the focal point of INS research, this technique is also non cell type specific as it triggers activity in non electrically excitable cells. Despite increasing interest, there remains to demonstrate well defined simultaneous astrocytic and neuronal signals in response to INS. Using calcium imaging, we show that INS has the capacity to initiate calcium signaling in both astrocytes and neurons simultaneously from the rostral lumbar spinal cord, each exhibiting distinct temporal and amplitude characteristics. Importantly, the mechanism underlying infrared-induced neuronal and astrocytic calcium signaling differ, with neuronal activity relying on sodium channels, whereas induced astrocytic signaling is predominantly influenced by extracellular calcium and TRPV4 channels. Furthermore, our findings demonstrate the frequency shift of neuronal calcium oscillations through infrared stimulation. By deepening our understanding in INS fundamentals, this technique holds great promise for advancing neuroscience, deepening our understanding of pathologies, and potentially paving the way for future clinical applications.
Assuntos
Astrócitos , Sinalização do Cálcio , Raios Infravermelhos , Neurônios , Medula Espinal , Astrócitos/metabolismo , Medula Espinal/fisiologia , Medula Espinal/metabolismo , Animais , Neurônios/metabolismo , Neurônios/fisiologia , Cálcio/metabolismo , Canais de Cátion TRPV/metabolismo , Locomoção/fisiologia , Rede Nervosa/fisiologia , Camundongos , Neuroglia/metabolismo , Neuroglia/fisiologiaRESUMO
Alzheimer's disease (AD), the leading cause of dementia, is a multifactorial disease influenced by aging, genetics, and environmental factors. miRNAs are crucial regulators of gene expression and play significant roles in AD onset and progression. This exploratory study analyzed the expression levels of 28 genes and 5 miRNAs (miR-124-3p, miR-125b-5p, miR-21-5p, miR-146a-5p, and miR-155-5p) related to AD pathology and neuroimmune responses using RT-qPCR. Analyses were conducted in the prefrontal cortex (PFC) and the hippocampus (HPC) of the 5xFAD mouse AD model at 6 and 9 months old. Data highlighted upregulated genes encoding for glial fibrillary acidic protein (Gfap), triggering receptor expressed on myeloid cells (Trem2) and cystatin F (Cst7), in the 5xFAD mice at both regions and ages highlighting their roles as critical disease players and potential biomarkers. Overexpression of genes encoding for CCAAT enhancer-binding protein alpha (Cebpa) and myelin proteolipid protein (Plp) in the PFC, as well as for BCL2 apoptosis regulator (Bcl2) and purinergic receptor P2Y12 (P2yr12) in the HPC, together with upregulated microRNA(miR)-146a-5p in the PFC, prevailed in 9-month-old animals. miR-155 positively correlated with miR-146a and miR-21 in the PFC, and miR-125b positively correlated with miR-155, miR-21, while miR-146a in the HPC. Correlations between genes and miRNAs were dynamic, varying by genotype, region, and age, suggesting an intricate, disease-modulated interaction between miRNAs and target pathways. These findings contribute to our understanding of miRNAs as therapeutic targets for AD, given their multifaceted effects on neurons and glial cells.
Assuntos
Doença de Alzheimer , Modelos Animais de Doenças , Hipocampo , MicroRNAs , Neuroglia , Neurônios , Animais , MicroRNAs/genética , MicroRNAs/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Camundongos , Neurônios/metabolismo , Neuroglia/metabolismo , Hipocampo/metabolismo , Camundongos Transgênicos , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Regulação da Expressão Gênica , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Córtex Pré-Frontal/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Proteína Glial Fibrilar Ácida/genética , MasculinoRESUMO
Even though several highly effective treatments have been developed for multiple sclerosis (MS), the underlying pathological mechanisms and drivers of the disease have not been fully elucidated. In recent years, there has been a growing interest in studying neuroinflammation in the context of glial cell involvement as there is increasing evidence of their central role in disease progression. Although glial cell communication and proper function underlies brain homeostasis and maintenance, their multiple effects in an MS brain remain complex and controversial. In this review, we aim to provide an overview of the contribution of glial cells, oligodendrocytes, astrocytes, and microglia in the pathology of MS during both the activation and orchestration of inflammatory mechanisms, as well as of their synergistic effects during the repair and restoration of function. Additionally, we discuss how the understanding of glial cell involvement in MS may provide new therapeutic targets either to limit disease progression or to facilitate repair.
Assuntos
Esclerose Múltipla , Neuroglia , Doenças Neuroinflamatórias , Humanos , Esclerose Múltipla/metabolismo , Esclerose Múltipla/patologia , Neuroglia/metabolismo , Neuroglia/patologia , Animais , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/patologia , Microglia/metabolismo , Microglia/patologia , Astrócitos/metabolismo , Astrócitos/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Encéfalo/metabolismo , Encéfalo/patologiaRESUMO
Neuroinflammation is considered to be one of the driving factors in Parkinson's disease (PD). This study was conducted using neuronal and glial cell cultures differentiated from induced pluripotent stem cells (iPSC) of healthy donors (HD) and PD patients with different PARK2 mutations (PD). Based on the results of RNA sequencing, qPCR and ELISA, we revealed transcriptional and post-transcriptional changes in HD and PD neurons cultivated in HD and PD glial-conditioned medium. We demonstrated that if one or both of the components of the system, neurons or glia, is Parkin-deficient, the interaction resulted in the down-regulation of a number of key genes related to inflammatory intracellular pathways and negative regulation of apoptosis in neurons, which might be neuroprotective. In PD neurons, the stress-induced up-regulation of APLNR was significantly stronger compared to HD neurons and was diminished by glial soluble factors, both HD and PD. PD neurons in PD glial conditioned medium increased APLN expression and also up-regulated apelin synthesis and release into intracellular fluid, which represented another compensatory action. Overall, the reported results indicate that neuronal self-defense mechanisms contribute to cell survival, which might be characteristic of PD patients with Parkin-deficiency.
Assuntos
Células-Tronco Pluripotentes Induzidas , Neuroglia , Neurônios , Doença de Parkinson , Ubiquitina-Proteína Ligases , Células-Tronco Pluripotentes Induzidas/metabolismo , Humanos , Doença de Parkinson/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/patologia , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Neuroglia/metabolismo , Neurônios/metabolismo , Transdução de Sinais , Meios de Cultivo Condicionados/farmacologia , Células Cultivadas , Inflamação/metabolismo , Inflamação/genética , Diferenciação CelularRESUMO
The neurovascular unit (NVU) is a complex multicellular structure that helps maintain cerebral homeostasis and blood-brain barrier (BBB) integrity. While extensive evidence links NVU alterations to cerebrovascular diseases and neurodegeneration, the underlying molecular mechanisms remain unclear. Here, we use zebrafish embryos carrying a mutation in Scavenger Receptor B2, a highly conserved endolysosomal protein expressed predominantly in Radial Glia Cells (RGCs), to investigate the interplay among different NVU components. Through live imaging and genetic manipulations, we demonstrate that compromised acidification of the endolysosomal compartment in mutant RGCs leads to impaired Notch3 signaling, thereby inducing excessive neurogenesis and reduced glial differentiation. We further demonstrate that alterations to the neuron/glia balance result in impaired VEGF and Wnt signaling, leading to severe vascular defects, hemorrhages, and a leaky BBB. Altogether, our findings provide insights into NVU formation and function and offer avenues for investigating diseases involving white matter defects and vascular abnormalities.
Assuntos
Barreira Hematoencefálica , Lisossomos , Neurogênese , Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/patologia , Lisossomos/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Células Ependimogliais/metabolismo , Células Ependimogliais/patologia , Endossomos/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Receptores Notch/metabolismo , Receptores Notch/genética , Neuroglia/metabolismo , Neuroglia/patologia , Diferenciação Celular , Células-Tronco/metabolismo , Via de Sinalização Wnt , Mutação , Neovascularização Fisiológica , Animais Geneticamente Modificados , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/irrigação sanguínea , Transdução de Sinais , AngiogêneseRESUMO
Understanding the sequence of cellular responses and their contributions to pathomorphogical changes in spinal white matter injuries is a prerequisite for developing efficient therapeutic strategies for spinal cord injury (SCI) as well as neurodegenerative and inflammatory diseases of the spinal cord such as amyotrophic lateral sclerosis and multiple sclerosis. We have developed several types of surgical procedures suitable for acute one-time and chronic recurrent in vivo multiphoton microscopy of spinal white matter [1]. Sophisticated surgical procedures were combined with transgenic mouse technology to image spinal tissue labeled with up to four fluorescent proteins (FPs) in axons, astrocytes, microglia, and blood vessels. To clearly separate the simultaneously excited FPs, spectral unmixing including iterative procedures was performed after imaging the diversely labeled spinal white matter with a custom-made 4-channel two-photon laser-scanning microscope. In our longitudinal multicellular studies of injured spinal white matter, we imaged axonal dynamics and invasion of microglia and astrocytes for a time course of over 200 days after SCI. Our methods offer ideal platforms for investigating acute and chronic cellular dynamics, cell-cell interactions, and metabolite fluctuations in health and disease as well as pharmacological manipulations in vivo.
Assuntos
Axônios , Camundongos Transgênicos , Traumatismos da Medula Espinal , Substância Branca , Animais , Substância Branca/patologia , Substância Branca/metabolismo , Substância Branca/diagnóstico por imagem , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/diagnóstico por imagem , Axônios/patologia , Axônios/metabolismo , Neuroglia/metabolismo , Neuroglia/patologia , Camundongos , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Medula Espinal/patologia , Medula Espinal/metabolismo , Microglia/metabolismo , Microglia/patologia , Astrócitos/metabolismo , Astrócitos/patologiaRESUMO
Traumatic spinal cord injury (tSCI) has complex pathophysiological events that begin after the initial trauma. One such event is fibroglial scar formation by fibroblasts and reactive astrocytes. A strong inhibition of axonal growth is caused by the activated astroglial cells as a component of fibroglial scarring through the production of inhibitory molecules, such as chondroitin sulfate proteoglycans or myelin-associated proteins. Here, we used neural precursor cells (aldynoglia) as promoters of axonal growth and a fibrin hydrogel gelled under alkaline conditions to support and guide neuronal cell growth, respectively. We added Tol-51 sulfoglycolipid as a synthetic inhibitor of astrocyte and microglia in order to test its effect on the axonal growth-promoting function of aldynoglia precursor cells. We obtained an increase in GFAP expression corresponding to the expected glial phenotype for aldynoglia cells cultured in alkaline fibrin. In co-cultures of dorsal root ganglia (DRG) and aldynoglia, the axonal growth promotion of DRG neurons by aldynoglia was not affected. We observed that the neural precursor cells first clustered together and then formed niches from which aldynoglia cells grew and connected to groups of adjacent cells. We conclude that the combination of alkaline fibrin with synthetic sulfoglycolipid Tol-51 increased cell adhesion, cell migration, fasciculation, and axonal growth capacity, promoted by aldynoglia cells. There was no negative effect on the behavior of aldynoglia cells after the addition of sulfoglycolipid Tol-51, suggesting that a combination of aldynoglia plus alkaline fibrin and Tol-51 compound could be useful as a therapeutic strategy for tSCI repair.
Assuntos
Axônios , Fibrina , Gânglios Espinais , Animais , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Gânglios Espinais/citologia , Axônios/metabolismo , Axônios/efeitos dos fármacos , Fibrina/metabolismo , Hidrogéis/química , Hidrogéis/farmacologia , Ratos , Glicolipídeos/farmacologia , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/citologia , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Células Cultivadas , Técnicas de Cocultura , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/tratamento farmacológico , Traumatismos da Medula Espinal/patologia , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Medula Espinal/metabolismo , Medula Espinal/efeitos dos fármacos , Medula Espinal/citologia , Movimento Celular/efeitos dos fármacosRESUMO
GM1 gangliosidosis is a lysosomal storage disorder characterized by the accumulation of GM1 ganglioside, leading to severe neurodegeneration and early mortality. The disease primarily affects the central nervous system, causing progressive neurodegeneration, including widespread neuronal loss and gliosis. To gain a deeper understanding of the neuropathology associated with GM1 gangliosidosis, we employed single-nucleus RNA sequencing to analyze brain tissues from both GM1 gangliosidosis model mice and control mice. No significant changes in cell proportions were detected between the two groups of animals. Differential expression analysis revealed cell type-specific changes in gene expression in neuronal and glial cells. Functional analysis highlighted the neurodegenerative processes, oxidative phosphorylation, and neuroactive ligand-receptor interactions as the significantly affected pathways. The contribution of the impairment of neurotransmitter system disruption and neuronal circuitry disruption was more important than neuroinflammatory responses to GM1 pathology. In 16-week-old GM1 gangliosidosis mice, no microglial or astrocyte activation or increased expression of innate immunity genes was detected. This suggested that nerve degeneration did not induce the inflammatory response but rather promoted glial cell clearance. Our findings provide a crucial foundation for understanding the cellular and molecular mechanisms of GM1 gangliosidosis, potentially guiding future therapeutic strategies.
Assuntos
Modelos Animais de Doenças , Gangliosidose GM1 , Animais , Gangliosidose GM1/genética , Gangliosidose GM1/metabolismo , Gangliosidose GM1/patologia , Camundongos , Transcriptoma , Neuroglia/metabolismo , Neuroglia/patologia , Perfilação da Expressão Gênica , Neurônios/metabolismo , Neurônios/patologia , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Encéfalo/metabolismo , Encéfalo/patologia , Gangliosídeo G(M1)/metabolismo , Análise de Célula Única , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Peripheral neuropathy (PN) constitutes a dose-limiting side effect of oxaliplatin chemotherapy that often compromises the efficacy of antineoplastic treatments. Sensory neurons damage in dorsal root ganglia (DRG) are the cellular substrate of PN complex molecular origin. Dehydropeptidase-1 (DPEP1) inhibitors have shown to avoid platin-induced nephrotoxicity without compromising its anticancer efficiency. The objective of this study was to describe DPEP1 expression in rat DRG in health and in early stages of oxaliplatin toxicity. To this end, we produced and characterized anti-DPEP1 polyclonal antibodies and used them to define the expression, and cellular and subcellular localization of DPEP1 by immunohistochemical confocal microscopy studies in healthy controls and short term (six days) oxaliplatin treated rats. RESULTS: DPEP1 is expressed mostly in neurons and in glia, and to a lesser extent in endothelial cells. Rats undergoing oxaliplatin treatment developed allodynia. TNF-ð¼ expression in DRG revealed a pattern of focal and at different intensity levels of neural cell inflammatory damage, accompanied by slight variations in DPEP1 expression in endothelial cells and in nuclei of neurons. CONCLUSIONS: DPEP1 is expressed in neurons, glia and endothelial cells of DRG. Oxaliplatin caused allodynia in rats and increased TNF-α expression in DRG neurons. The expression of DPEP1 in neurons and other cells of DRG suggest this protein as a novel strategic molecular target in the prevention of oxaliplatin-induced acute neurotoxicity.