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1.
Sci Rep ; 12(1): 14848, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36050459

RESUMO

Granule neurons are the most common cell type in the cerebellum. They are generated in the external granule layer and migrate inwardly, forming the internal granule layer. Small Rho GTPases play various roles during development of the nervous system and may be involved in generation, differentiation and migration of granule neurons. We deleted Rac1, a member of small Rho GTPases, by GFAP-Cre driver in cerebellar granule neurons and Bergmann glial cells. Rac1flox/flox; Cre mice showed impaired migration and slight reduction in the number of granule neurons in the internal granule layer. Deletion of both Rac1 and Rac3 resulted in almost complete absence of granule neurons. Rac-deficient granule neurons differentiated into p27 and NeuN-expressing post mitotic neurons, but died before migration to the internal granule layer. Loss of Rac3 has little effect on granule neuron development. Rac1flox/flox; Rac3+/-; Cre mice showed intermediate phenotype between Rac1flox/flox; Cre and Rac1flox/flox; Rac3-/-; Cre mice in both survival and migration of granule neurons. Rac3 itself seems to be unimportant in the development of the cerebellum, but has some roles in Rac1-deleted granule neurons. Conversely, overall morphology of Rac1+/flox; Rac3-/-; Cre cerebella was normal. One allele of Rac1 is therefore thought to be sufficient to promote development of cerebellar granule neurons.


Assuntos
Proteínas rac de Ligação ao GTP , Proteínas rac1 de Ligação ao GTP , Animais , Cerebelo/metabolismo , Camundongos , Camundongos Knockout , Neurogênese/fisiologia , Neuroglia/metabolismo , Neurônios/metabolismo , Proteínas rac de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo
2.
Int J Mol Sci ; 23(17)2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-36076908

RESUMO

Central nervous system (CNS) homeostasis is closely linked to the delicate balance of the microenvironment in which different cellular components of the neurovascular unit (NVU) coexist. Intercellular communication plays a pivotal role in exchanges of signaling molecules and mediators essential for survival functions, as well as in the removal of disturbing elements that can lead to related pathologies. The specific signatures of connexins (Cxs), proteins which form either gap junctions (GJs) or hemichannels (HCs), represent the biological substrate of the pathophysiological balance. Connexin 43 (Cx43) is undoubtedly one of the most important factors in glia-neuro-vascular crosstalk. Herein, Cxs signatures of every NVU component are highlighted and their critical influence on functional processes in healthy and pathological conditions of nervous microenvironment is reviewed.


Assuntos
Conexinas , Junções Comunicantes , Comunicação Celular/fisiologia , Conexinas/metabolismo , Junções Comunicantes/metabolismo , Neuroglia/metabolismo , Transdução de Sinais/fisiologia
3.
Front Immunol ; 13: 956340, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36072579

RESUMO

Clostridioides difficile (C. difficile) produces toxins A (TcdA) and B (TcdB), both associated with intestinal damage and diarrhea. Pannexin-1 (Panx1) channels allows the passage of messenger molecules, such as adenosine triphosphate (ATP), which in turn activate the P2X7 receptors (P2X7R) that regulate inflammation and cell death in inflammatory bowel diseases. The aim of this study was to verify the effect of C. difficile infection (CDI) in the expression of Panx1 and P2X7R in intestinal tissues of mice, as well as their role in cell death and IL-6 expression induced by TcdA and TcdB in enteric glial cells (EGCs). Male C57BL/6 mice (8 weeks of age) were infected with C. difficile VPI10463, and the control group received only vehicle per gavage. After three days post-infection (p.i.), cecum and colon samples were collected to evaluate the expression of Panx1 by immunohistochemistry. In vitro, EGCs (PK060399egfr) were challenged with TcdA or TcdB, in the presence or absence of the Panx1 inhibitor (10Panx trifluoroacetate) or P2X7R antagonist (A438079), and Panx1 and P2X7R expression, caspase-3/7 activity and phosphatidylserine binding to annexin-V, as well as IL-6 expression were assessed. CDI increased the levels of Panx1 in cecum and colon of mice compared to the control group. Panx1 inhibitor decreased caspase-3/7 activity and phosphatidylserine-annexin-V binding, but not IL-6 gene expression in TcdA and TcdB-challenged EGCs. P2X7 receptor antagonist accentually reduced caspase-3/7 activity, phosphatidylserine-annexin-V binding, and IL-6 gene expression in TcdA and TcdB-challenged EGCs. In conclusion, Panx1 is increased during CDI and plays an important role in the effects of C. difficile toxins in EGCs, participating in cell death induced by both toxins by promoting caspase-3/7 activation via P2X7R, which is also involved in IL-6 expression induced by both toxins.


Assuntos
Toxinas Bacterianas , Clostridioides difficile , Conexinas , Proteínas do Tecido Nervoso , Receptores Purinérgicos P2X7 , Animais , Anexinas , Toxinas Bacterianas/metabolismo , Caspase 3/metabolismo , Morte Celular , Conexinas/genética , Conexinas/metabolismo , Mediadores da Inflamação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neuroglia/metabolismo , Fosfatidilserinas , Receptores Purinérgicos P2X7/genética
4.
Traffic ; 23(10): 506-520, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36053864

RESUMO

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of familial and sporadic Parkinson's disease. A plethora of evidence has indicated a role for LRRK2 in endolysosomal trafficking in neurons, while LRRK2 function in glia, although highly expressed, remains largely unknown. Here, we present evidence that LRRK2/dLRRK mediates a lysosomal pathway that contributes to glial cell death and the survival of dopaminergic (DA) neurons. LRRK2/dLRRK knockdown in the immortalized microglia or flies results in enlarged and swelling lysosomes fewer in number. These lysosomes are less mobile, wrongly acidified, exhibit defective membrane permeability and reduced activity of the lysosome hydrolase cathepsin B. In addition, LRRK2/dLRRK depletion causes glial apoptosis, DA neurodegeneration, and locomotor deficits in an age-dependent manner. Taken together, these findings demonstrate a functional role of LRRK2/dLRRK in regulating the glial lysosomal pathway; deficits in lysosomal biogenesis and function linking to glial apoptosis potentially underlie the mechanism of DA neurodegeneration, providing insights on LRRK2/dLRRK function in normal and pathological brains.


Assuntos
Catepsina B , Neurônios Dopaminérgicos , Catepsina B/genética , Catepsina B/metabolismo , Morte Celular , Neurônios Dopaminérgicos/metabolismo , Leucina/genética , Leucina/metabolismo , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Lisossomos/metabolismo , Mutação , Neuroglia/metabolismo
5.
Proc Natl Acad Sci U S A ; 119(34): e2208513119, 2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35969780

RESUMO

Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease characterized by progressive ataxia and degeneration of specific neuronal populations, including Purkinje cells (PCs) in the cerebellum. Previous studies have demonstrated a critical role for various evolutionarily conserved signaling pathways in cerebellar patterning, such as the Wnt-ß-catenin pathway; however, the roles of these pathways in adult cerebellar function and cerebellar neurodegeneration are largely unknown. In this study, we found that Wnt-ß-catenin signaling activity was progressively enhanced in multiple cell types in the adult SCA1 mouse cerebellum, and that activation of this signaling occurs in an ataxin-1 polyglutamine (polyQ) expansion-dependent manner. Genetic manipulation of the Wnt-ß-catenin signaling pathway in specific cerebellar cell populations revealed that activation of Wnt-ß-catenin signaling in PCs alone was not sufficient to induce SCA1-like phenotypes, while its activation in astrocytes, including Bergmann glia (BG), resulted in gliosis and disrupted BG localization, which was replicated in SCA1 mouse models. Our studies identify a mechanism in which polyQ-expanded ataxin-1 positively regulates Wnt-ß-catenin signaling and demonstrate that different cell types have distinct responses to the enhanced Wnt-ß-catenin signaling in the SCA1 cerebellum, underscoring an important role of BG in SCA1 pathogenesis.


Assuntos
Neuroglia , Células de Purkinje , Ataxias Espinocerebelares , Via de Sinalização Wnt , Animais , Ataxina-1/genética , Ataxina-1/metabolismo , Cerebelo/metabolismo , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Neuroglia/metabolismo , Peptídeos , Células de Purkinje/metabolismo , Ataxias Espinocerebelares/patologia , beta Catenina/genética , beta Catenina/metabolismo
6.
Proc Natl Acad Sci U S A ; 119(34): e2110097119, 2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-35969789

RESUMO

While the role of barrier function in establishing a protective, nutrient-rich, and ionically balanced environment for neurons has been appreciated for some time, little is known about how signaling cues originating in barrier-forming cells participate in maintaining barrier function and influence synaptic activity. We have identified Delta/Notch signaling in subperineurial glia (SPG), a crucial glial type for Drosophila motor axon ensheathment and the blood-brain barrier, to be essential for controlling the expression of matrix metalloproteinase 1 (Mmp1), a major regulator of the extracellular matrix (ECM). Our genetic analysis indicates that Delta/Notch signaling in SPG exerts an inhibitory control on Mmp1 expression. In the absence of this inhibition, abnormally enhanced Mmp1 activity disrupts septate junctions and glial ensheathment of peripheral motor nerves, compromising neurotransmitter release at the neuromuscular junction (NMJ). Temporally controlled and cell type-specific transgenic analysis shows that Delta/Notch signaling inhibits transcription of Mmp1 by inhibiting c-Jun N-terminal kinase (JNK) signaling in SPG. Our results provide a mechanistic insight into the regulation of neuronal health and function via glial-initiated signaling and open a framework for understanding the complex relationship between ECM regulation and the maintenance of barrier function.


Assuntos
Proteínas de Drosophila , Metaloproteinase 1 da Matriz , Neuroglia , Transmissão Sináptica , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Matriz Extracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Metaloproteinase 1 da Matriz/metabolismo , Proteínas de Membrana/metabolismo , Neuroglia/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais
7.
Nat Commun ; 13(1): 4999, 2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-36008397

RESUMO

Neural stem cells (NSCs) live in an intricate cellular microenvironment supporting their activity, the niche. Whilst shape and function are inseparable, the morphogenetic aspects of niche development are poorly understood. Here, we use the formation of a glial niche to investigate acquisition of architectural complexity. Cortex glia (CG) in Drosophila regulate neurogenesis and build a reticular structure around NSCs. We first show that individual CG cells grow tremendously to ensheath several NSC lineages, employing elaborate proliferative mechanisms which convert these cells into syncytia rich in cytoplasmic bridges. CG syncytia further undergo homotypic cell-cell fusion, using defined cell surface receptors and actin regulators. Cellular exchange is however dynamic in space and time. This atypical cell fusion remodels cellular borders, restructuring the CG syncytia. Ultimately, combined growth and fusion builds the multi-level architecture of the niche, and creates a modular, spatial partition of the NSC population. Our findings provide insights into how a niche forms and organises while developing intimate contacts with a stem cell population.


Assuntos
Drosophila , Células-Tronco Neurais , Animais , Morfogênese , Células-Tronco Neurais/metabolismo , Neurogênese/genética , Neuroglia/metabolismo , Nicho de Células-Tronco/fisiologia
8.
Int J Mol Sci ; 23(16)2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-36012401

RESUMO

BACKGROUND: In recent years, the attention of the scientific world has focused on a clearance system of brain waste metabolites, called the glymphatic system, based on its similarity to the lymphatic system in peripheral tissue and the relevant role of the AQP4 glial channels and described for the first time in 2012. Consequently, numerous studies focused on its role in organ damage in cases of neuropathologies, including TBI. METHODS: To evaluate the role that the glymphatic system has in the pathogenesis of TBI, on 23 March 2022, a systematic review of the literature according to PRISMA guidelines was carried out using the SCOPUS and Medline (via PubMed) databases, resulting in 12 articles after the selection process. DISCUSSION AND CONCLUSION: The present review demonstrated that an alteration of AQP4 is associated with the accumulation of substances S100b, GFAP, and NSE, known markers of TBI in the forensic field. In addition, the alteration of the functionality of AQP4 favors edema, which, as already described, constitutes alterations of secondary brain injuries. Moreover, specific areas of the brain were demonstrated to be prone to alterations of the glymphatic pathway, suggesting their involvement in post-TBI damage. Therefore, further studies are mandatory. In this regard, a study protocol on cadavers is also proposed, based on the analyzed evidence.


Assuntos
Lesões Encefálicas , Sistema Glinfático , Encéfalo/metabolismo , Lesões Encefálicas/metabolismo , Sistema Glinfático/metabolismo , Humanos , Sistema Linfático/metabolismo , Neuroglia/metabolismo
9.
Nat Commun ; 13(1): 4714, 2022 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-35953475

RESUMO

Glutamate is a pivotal excitatory neurotransmitter in mammalian brains, but excessive glutamate causes numerous neural disorders. Almost all extracellular glutamate is retrieved by the glial transporter, Excitatory Amino Acid Transporter 2 (EAAT2), belonging to the SLC1A family. However, in some cancers, EAAT2 expression is enhanced and causes resistance to therapies by metabolic disturbance. Despite its crucial roles, the detailed structural information about EAAT2 has not been available. Here, we report cryo-EM structures of human EAAT2 in substrate-free and selective inhibitor WAY213613-bound states at 3.2 Å and 2.8 Å, respectively. EAAT2 forms a trimer, with each protomer consisting of transport and scaffold domains. Along with a glutamate-binding site, the transport domain possesses a cavity that could be disrupted during the transport cycle. WAY213613 occupies both the glutamate-binding site and cavity of EAAT2 to interfere with its alternating access, where the sensitivity is defined by the inner environment of the cavity. We provide the characterization of the molecular features of EAAT2 and its selective inhibition mechanism that may facilitate structure-based drug design for EAAT2.


Assuntos
Transportador 2 de Aminoácido Excitatório/química , Ácido Glutâmico , Animais , Sítios de Ligação , Encéfalo/metabolismo , Transportador 2 de Aminoácido Excitatório/genética , Transportador 2 de Aminoácido Excitatório/metabolismo , Transportador 3 de Aminoácido Excitatório/genética , Transportador 3 de Aminoácido Excitatório/metabolismo , Ácido Glutâmico/metabolismo , Humanos , Mamíferos/metabolismo , Neuroglia/metabolismo
10.
Sci Rep ; 12(1): 14749, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36042338

RESUMO

The Drosophila Ntan1 gene encodes an N-terminal asparagine amidohydrolase that we show is highly conserved throughout evolution. Protein isoforms share more than 72% of similarity with their human counterparts. At the cellular level, this gene regulates the type of glial cell growth in Drosophila larvae by its different expression levels. The Drosophila Ntan1 gene has 4 transcripts that encode 2 protein isoforms. Here we describe that although this gene is expressed at all developmental stages and adult organs tested (eye, antennae and brain) there are some transcript-dependent specificities. Therefore, both quantitative and qualitative cues could account for gene function. However, widespread developmental stage and organ-dependent expression could be masking cell-specific constraints that can be explored in Drosophila by using Gal4 drivers. We report a new genetic driver within this gene, Mz317-Gal4, that recapitulates the Ntan1 gene expression pattern in adults. It shows specific expression for perineural glia in the olfactory organs but mixed expression with some neurons in the adult brain. Memory and social behavior disturbances in mice and cancer and schizophrenia in humans have been linked to the Ntan1 gene. Therefore, these new tools in Drosophila may contribute to our understanding of the cellular basis of these alterations.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Humanos , Camundongos , Neuroglia/metabolismo , Neurônios/metabolismo , Fenótipo
11.
J Extracell Vesicles ; 11(9): e12254, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36043482

RESUMO

Cell-cell interactions in the central nervous system are based on the release of molecules mediating signal exchange and providing structural and trophic support through vesicular exocytosis and the formation of extracellular vesicles. The specific mechanisms employed by each cell type in the brain are incompletely understood. Here, we explored the means of communication used by Müller cells, a type of radial glial cells in the retina, which forms part of the central nervous system. Using immunohistochemical, electron microscopic, and molecular analyses, we provide evidence for the release of distinct extracellular vesicles from endfeet and microvilli of retinal Müller cells in adult mice in vivo. We identify VAMP5 as a Müller cell-specific SNARE component that is part of extracellular vesicles and responsive to ischemia, and we reveal differences between the secretomes of immunoaffinity-purified Müller cells and neurons in vitro. Our findings suggest extracellular vesicle-based communication as an important mediator of cellular interactions in the retina.


Assuntos
Vesículas Extracelulares , Neuroglia , Animais , Células Ependimogliais/metabolismo , Camundongos , Neuroglia/metabolismo , Neurônios/metabolismo , Retina/metabolismo
12.
Mol Neurobiol ; 59(10): 6447-6459, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35962300

RESUMO

Neural regeneration has troubled investigators worldwide in the past decades. Currently, cell transplantation emerged as a breakthrough targeted therapy for spinal cord injury (SCI) in the neurotrauma field, which provides a promising strategy in neural regeneration. Olfactory ensheathing cells (OECs), a specialized type of glial cells, is considered as the excellent candidate due to its unique variable and intrinsic regeneration-supportive properties. In fact, OECs could support olfactory receptor neuron turnover and axonal extension, which is essential to maintain the function of olfactory nervous system. Hitherto, an increasing number of literatures demonstrate that transplantation of OECs exerts vital roles in neural regeneration and functional recovery after neural injury, including central and peripheral nervous system. It is common knowledge that the deteriorating microenvironment (ischemia, hypoxia, scar, acute and chronic inflammation, etc.) resulting from injured nervous system is adverse for neural regeneration. Interestingly, recent studies indicated that OECs could promote neural repair through improvement of the disastrous microenvironments, especially to the overwhelmed inflammatory responses. Although OECs possess unusual advantages over other cells for neural repair, particularly in SCI, the mechanisms of OEC-mediated neural repair are still controversial with regard to anti-inflammation. Therefore, it is significant to summarize the anti-inflammation property of OECs, which is helpful to understand the biological characteristics of OECs and drive future studies. Here, we mainly focus on the anti-inflammatory role of OECs to make systematic review and discuss OEC-based therapy for CNS injury.


Assuntos
Bulbo Olfatório , Traumatismos da Medula Espinal , Anti-Inflamatórios/metabolismo , Transplante de Células/métodos , Humanos , Regeneração Nervosa/fisiologia , Neuroglia/metabolismo , Bulbo Olfatório/metabolismo , Medula Espinal
13.
Sci Adv ; 8(28): eabn3326, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35857503

RESUMO

Recessive variants in GBA1 cause Gaucher disease, a prevalent form of lysosome storage disease. GBA1 encodes a lysosomal enzyme that hydrolyzes glucosylceramide (GlcCer) into glucose and ceramide. Its loss causes lysosomal dysfunction and increased levels of GlcCer. We generated a null allele of the Drosophila ortholog Gba1b by inserting the Gal4 using CRISPR-Cas9. Here, we show that Gba1b is expressed in glia but not in neurons. Glial-specific knockdown recapitulates the defects found in Gba1b mutants, and these can be rescued by glial expression of human GBA1. We show that GlcCer is synthesized upon neuronal activity, and it is transported from neurons to glia through exosomes. Furthermore, we found that glial TGF-ß/BMP induces the transfer of GlcCer from neurons to glia and that the White protein, an ABCG transporter, promotes GlcCer trafficking to glial lysosomes for degradation.


Assuntos
Exossomos , Glucosilceramidas , Animais , Drosophila/metabolismo , Exossomos/metabolismo , Glucosilceramidase/genética , Glucosilceramidase/metabolismo , Glucosilceramidas/metabolismo , Humanos , Lisossomos/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo
14.
ASN Neuro ; 14: 17590914221116574, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35903937

RESUMO

SUMMARY STATEMENT: EAAT1/GLAST down-regulates its expression and function at the transcriptional level by activating a signaling pathway that includes PI3K, PKC and NF-κB, favoring the notion of an activity-dependent fine-tuning of glutamate recycling and its synaptic transactions through glial cells.


Assuntos
Transportador 1 de Aminoácido Excitatório , Regulação da Expressão Gênica , Células Cultivadas , Transportador 1 de Aminoácido Excitatório/genética , Transportador 1 de Aminoácido Excitatório/metabolismo , Regulação da Expressão Gênica/genética , Ácido Glutâmico/metabolismo , Neuroglia/metabolismo
15.
Glycoconj J ; 39(4): 499-512, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35877057

RESUMO

Neu1 is a glycosidase that releases sialic acids from the non-reducing ends of glycoconjugates, and its enzymatic properties are conserved among vertebrates. Recently, Neu1-KO zebrafish were generated using genome editing technology, and the KO fish showed abnormal emotional behavior, such as low schooling, low aggressiveness, and excess exploratory behavior, accompanied by the downregulation of anxiety-related genes. To examine the alteration of neuronal and glial cells in Neu1-KO zebrafish, we analyzed the molecular profiles in the zebrafish brain, focusing on the midbrain and telencephalon. Using immunohistochemistry, we found that signals of Maackia amurensis (MAM) lectin that recognizes Sia α2-3 linked glycoconjugates were highly increased in Neu1-KO zebrafish brains, accompanied by an increase in Lamp1a. Neu1-KO zebrafish suppressed the gene expression of AMPA-type glutamate receptors such as gria1a, gria2a, and gria3b, and vesicular glutamate transporter 1. Additionally, Neu1-KO zebrafish induced the hyperactivation of astrocytes accompanied by an increase in Gfap and phosphorylated ERK levels, while the mRNA levels of astrocyte glutamate transporters (eaat1a, eaat1c, and eaat2) were downregulated. The mRNA levels of sypb and ho1b, which are markers of synaptic plasticity, were also suppressed by Neu1 deficiency. Abnormal activity of microglia was also revealed by IHC, and the expressions of iNOS and IL-1ß, an inflammatory cytokine, were increased in Neu1-KO zebrafish. Furthermore, drastic neuronal degeneration was detected in Neu1-KO zebrafish using Fluoro-Jade B staining. Collectively, the neuronal and glial abnormalities in Neu1-KO zebrafish may be caused by changes in the excitatory neurotransmitter glutamate and involved in the emotional abnormalities.


Assuntos
Neuraminidase , Peixe-Zebra , Animais , Glutamatos , Glicoconjugados , Neuraminidase/genética , Neuroglia/metabolismo , RNA Mensageiro/metabolismo , Peixe-Zebra/genética
16.
J Neurosci Res ; 100(10): 1890-1907, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35853016

RESUMO

Chronic pain is more prevalent and reported to be more severe in women. Opioid analgesics are less effective in women and result in stronger nauseant effects. The neurobiological mechanisms underlying these sex differences have yet to be clearly defined, though recent research has suggested neuronal-glial interactions are likely involved. We have previously shown that similar to people, morphine is less effective at reducing pain behaviors in female rats. In this study, we used the immunohistochemical detection of glial fibrillary acidic protein (GFAP) expression to investigate sex differences in astrocyte density and morphology in six medullary regions known to be modulated by pain and/or opioids. Morphine administration had small sex-dependent effects on overall GFAP expression, but not on astrocyte morphology, in the rostral ventromedial medulla, the subnucleus reticularis dorsalis, and the area postrema. Significant sex differences in the density and morphology of GFAP immunopositive astrocytes were detected in all six regions. In general, GFAP-positive cells in females showed smaller volumes and reduced complexity than those observed in males. Furthermore, females showed lower overall GFAP expression in all regions except for the area postrema, the critical medullary region responsible for opioid-induced nausea and emesis. These data support the possibility that differences in astrocyte activity might underlie the sex differences seen in the processing of opioids in the context of chronic neuropathic pain.


Assuntos
Morfina , Neuralgia , Analgésicos Opioides/farmacologia , Animais , Astrócitos/metabolismo , Tronco Encefálico , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Masculino , Morfina/farmacologia , Neuralgia/metabolismo , Neuroglia/metabolismo , Ratos , Caracteres Sexuais
17.
Cell Mol Life Sci ; 79(8): 442, 2022 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-35864342

RESUMO

Clostridioides difficile infection (CDI) causes nosocomial/antibiotic-associated gastrointestinal diseases with dramatically increasing global incidence and mortality rates. The main C. difficile virulence factors, toxins A and B (TcdA/TcdB), cause cytopathic/cytotoxic effects and inflammation. We demonstrated that TcdB induces caspase-dependent, mitochondria-independent enteric glial cell (EGC) apoptosis that is enhanced by the pro-inflammatory cytokines TNF-α and IFN-γ (CKs) by increasing caspase-3/7/9 and PARP activation. Because this cytotoxic synergism is important for CDI pathogenesis, we investigated the apoptotic pathways involved in TcdB- and TcdB + CK-induced apoptosis indepth. EGCs were pre-treated with the inhibitors BAF or Q-VD-OPh (pan-caspase), Z-DEVD-fmk (caspase-3/7), Z-IETD-fmk (caspase-8), PD150606 (calpains), and CA-074Me (cathepsin B) 1 h before TcdB exposure, while CKs were given 1.5 h after TcdB exposure, and assays were performed at 24 h. TcdB and TcdB + CKs induced apoptosis through three signalling pathways activated by calpains, caspases and cathepsins, which all are involved both in induction and execution apoptotic signalling under both conditions but to different degrees in TcdB and TcdB + CKs especially as regards to signal transduction mediated by these proteases towards downstream effects (apoptosis). Calpain activation by Ca2+ influx is the first pro-apoptotic event in TcdB- and TcdB + CK-induced EGC apoptosis and causes caspase-3, caspase-7 and PARP activation. PARP is also directly activated by calpains which are responsible of about 75% of apoptosis in TcdB and 62% in TcdB + CK which is both effector caspase-dependent and -independent. Initiator caspase-8 activation mediated by TcdB contributes to caspase-3/caspase-7 and PARP activation and is responsible of about 28% of apoptosis in both conditions. Caspase-3/caspase-7 activation is weakly responsible of apoptosis, indeed we found that it mediates 27% of apoptosis only in TcdB. Cathepsin B contributes to triggering pro-apoptotic signal and is responsible in both conditions of about 35% of apoptosis by a caspase-independent manner, and seems to regulate the caspase-3 and caspase-7 cleaved fragment levels, highlighting the complex interaction between these cysteine protease families activated during TcdB-induced apoptosis. Further a relevant difference between TcdB- and TcdB + CK-induced apoptosis is that TcdB-induced apoptosis increased slowly reaching at 72 h the value of 18.7%, while TcdB + CK-induced apoptosis increased strongly reaching at 72 h the value of 60.6%. Apoptotic signalling activation by TcdB + CKs is enriched by TNF-α-induced NF-κB signalling, inhibition of JNK activation and activation of AKT. In conclusion, the ability of C. difficile to activate three apoptotic pathways represents an important strategy to overcome resistance against its cytotoxic activity.


Assuntos
Toxinas Bacterianas , Clostridioides difficile , Infecções por Clostridium , Apoptose/fisiologia , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/toxicidade , Calpaína/metabolismo , Caspase 3/metabolismo , Caspase 7/metabolismo , Caspase 7/farmacologia , Caspases/metabolismo , Catepsina B/metabolismo , Citocinas/metabolismo , Humanos , Neuroglia/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/farmacologia
18.
Development ; 149(15)2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35815610

RESUMO

Significant progress has been made in elucidating the basic principles that govern neuronal specification in the developing central nervous system. In contrast, much less is known about the origin of astrocytic diversity. Here, we demonstrate that a restricted pool of progenitors in the mouse spinal cord, expressing the transcription factor Dbx1, produces a subset of astrocytes, in addition to interneurons. Ventral p0-derived astrocytes (vA0 cells) exclusively populate intermediate regions of spinal cord with extraordinary precision. The postnatal vA0 population comprises gray matter protoplasmic and white matter fibrous astrocytes and a group of cells with strict radial morphology contacting the pia. We identified that vA0 cells in the lateral funiculus are distinguished by the expression of reelin and Kcnmb4. We show that Dbx1 mutants have an increased number of vA0 cells at the expense of p0-derived interneurons. Manipulation of the Notch pathway, together with the alteration in their ligands seen in Dbx1 knockouts, suggest that Dbx1 controls neuron-glial balance by modulating Notch-dependent cell interactions. In summary, this study highlights that restricted progenitors in the dorsal-ventral neural tube produce region-specific astrocytic subgroups and that progenitor transcriptional programs highly influence glial fate and are instrumental in creating astrocyte diversity.


Assuntos
Astrócitos , Medula Espinal , Animais , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Interneurônios/metabolismo , Subunidades beta do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Camundongos , Neuroglia/metabolismo , Transdução de Sinais/genética , Medula Espinal/metabolismo
19.
Nat Metab ; 4(7): 813-825, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35879459

RESUMO

Communication between the periphery and the brain is key for maintaining energy homeostasis. To do so, peripheral signals from the circulation reach the brain via the circumventricular organs (CVOs), which are characterized by fenestrated vessels lacking the protective blood-brain barrier (BBB). Glial cells, by virtue of their plasticity and their ideal location at the interface of blood vessels and neurons, participate in the integration and transmission of peripheral information to neuronal networks in the brain for the neuroendocrine control of whole-body metabolism. Metabolic diseases, such as obesity and type 2 diabetes, can disrupt the brain-to-periphery communication mediated by glial cells, highlighting the relevance of these cell types in the pathophysiology of such complications. An improved understanding of how glial cells integrate and respond to metabolic and humoral signals has become a priority for the discovery of promising therapeutic strategies to treat metabolic disorders. This Review highlights the role of glial cells in the exchange of metabolic signals between the periphery and the brain that are relevant for the regulation of whole-body energy homeostasis.


Assuntos
Diabetes Mellitus Tipo 2 , Barreira Hematoencefálica/metabolismo , Encéfalo/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Homeostase/fisiologia , Humanos , Neuroglia/metabolismo
20.
Mucosal Immunol ; 15(5): 964-976, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35869148

RESUMO

Intestinal epithelial barrier function is compromised in inflammatory bowel disease and barrier dysfunction contributes to disease progression. Extracellular nucleotides/nucleosides generated in gut inflammation may regulate barrier function through actions on diverse cell types. Enteric glia modulate extracellular purinergic signaling and exert pathophysiological effects on mucosal permeability. These glia may regulate inflammation with paracrine responses, theoretically mediated via adenosine 2B receptor (A2BR) signaling. As the cell-specific roles of A2BRs in models of colitis and barrier dysfunction are unclear, we studied glial A2BRs in acute dextran sodium sulfate (DSS) colitis. We performed and validated conditional ablation of glial A2BRs in Sox10CreERT2+/-;Adora2bf/f mice. Overt intestinal disease activity indices in DSS-colitis were comparable between Sox10CreERT2+/-;Adora2bf/f mice and littermate controls. However, ablating glial A2BRs protected against barrier dysfunction following acute DSS-colitis. These benefits were associated with the normalization of tight junction protein expression and localization including claudin-1, claudin-8, and occludin. Glial A2BR signaling increased levels of proinflammatory mediators in the colon and cell-intrinsic regulation of genes including Csf3, Cxcl1, Cxcl10, and Il6. Our studies show that glial A2BR signaling exacerbates immune responses during DSS-colitis and that this adenosinergic cell-specific mechanism contributes to persistent gut epithelial barrier dysfunction.


Assuntos
Colite , Mucosa Intestinal , Adenosina/metabolismo , Animais , Colite/induzido quimicamente , Colite/genética , Colite/metabolismo , Colo/metabolismo , Sulfato de Dextrana , Modelos Animais de Doenças , Inflamação/metabolismo , Mucosa Intestinal/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Neuroglia/metabolismo
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