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1.
J Mol Neurosci ; 74(2): 40, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38594388

RESUMO

Astrocytes, the most prevalent cells in the central nervous system (CNS), can be transformed into neurons and oligodendrocyte progenitor cells (OPCs) using specific transcription factors and some chemicals. In this study, we present a cocktail of small molecules that target different signaling pathways to promote astrocyte conversion to OPCs. Astrocytes were transferred to an OPC medium and exposed for five days to a small molecule cocktail containing CHIR99021, Forskolin, Repsox, LDN, VPA and Thiazovivin before being preserved in the OPC medium for an additional 10 days. Once reaching the OPC morphology, induced cells underwent immunocytofluorescence evaluation for OPC markers while checked for lacking the astrocyte markers. To test the in vivo differentiation capabilities, induced OPCs were transplanted into demyelinated mice brains treated with cuprizone over 12 weeks. Two distinct lines of astrocytes demonstrated the potential of conversion to OPCs using this small molecule cocktail as verified by morphological changes and the expression of PDGFR and O4 markers as well as the terminal differentiation to oligodendrocytes expressing MBP. Following transplantation into demyelinated mice brains, induced OPCs effectively differentiated into mature oligodendrocytes. The generation of OPCs from astrocytes via a small molecule cocktail may provide a new avenue for producing required progenitors necessary for myelin repair in diseases characterized by the loss of myelin such as multiple sclerosis.


Assuntos
Esclerose Múltipla , Células Precursoras de Oligodendrócitos , Camundongos , Animais , Esclerose Múltipla/terapia , Esclerose Múltipla/metabolismo , Astrócitos/metabolismo , Células Precursoras de Oligodendrócitos/metabolismo , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Diferenciação Celular/fisiologia , Modelos Animais de Doenças , Linhagem Celular
2.
J Neurosci Res ; 102(4): e25334, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38656648

RESUMO

Iron deficiency (ID) has been shown to affect central nervous system (CNS) development and induce hypomyelination. Previous work from our laboratory in a gestational ID model showed that both oligodendrocyte (OLG) and astrocyte (AST) maturation was impaired. To explore the contribution of AST iron to the myelination process, we generated an in vitro ID model by silencing divalent metal transporter 1 (DMT1) in AST (siDMT1 AST) or treating AST with Fe3+ chelator deferoxamine (DFX; DFX AST). siDMT1 AST showed no changes in proliferation but remained immature. Co-cultures of oligodendrocyte precursors cells (OPC) with siDMT1 AST and OPC cultures incubated with siDMT1 AST-conditioned media (ACM) rendered a reduction in OPC maturation. These findings correlated with a decrease in the expression of AST-secreted factors IGF-1, NRG-1, and LIF, known to promote OPC differentiation. siDMT1 AST also displayed increased mitochondrial number and reduced mitochondrial size as compared to control cells. DFX AST also remained immature and DFX AST-conditioned media also hampered OPC maturation in culture, in keeping with a decrease in the expression of AST-secreted growth factors IGF-1, NRG-1, LIF, and CNTF. DFX AST mitochondrial morphology and number showed results similar to those observed in siDMT1 AST. In sum, our results show that ID, induced through two different methods, impacts AST maturation and mitochondrial functioning, which in turn hampers OPC differentiation.


Assuntos
Astrócitos , Diferenciação Celular , Deficiências de Ferro , Oligodendroglia , Astrócitos/metabolismo , Astrócitos/efeitos dos fármacos , Oligodendroglia/metabolismo , Oligodendroglia/efeitos dos fármacos , Animais , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Células Cultivadas , Proteínas de Transporte de Cátions/metabolismo , Técnicas de Cocultura , Meios de Cultivo Condicionados/farmacologia , Ratos , Células Precursoras de Oligodendrócitos/efeitos dos fármacos , Células Precursoras de Oligodendrócitos/metabolismo , Desferroxamina/farmacologia , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/fisiologia , Ferro/metabolismo
3.
J Cell Biol ; 223(7)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38652118

RESUMO

Chromatin-remodeling protein BRG1/SMARCA4 is pivotal for establishing oligodendrocyte (OL) lineage identity. However, its functions for oligodendrocyte-precursor cell (OPC) differentiation within the postnatal brain and during remyelination remain elusive. Here, we demonstrate that Brg1 loss profoundly impairs OPC differentiation in the brain with a comparatively lesser effect in the spinal cord. Moreover, BRG1 is critical for OPC remyelination after injury. Integrative transcriptomic/genomic profiling reveals that BRG1 exhibits a dual role by promoting OPC differentiation networks while repressing OL-inhibitory cues and proneuronal programs. Furthermore, we find that BRG1 interacts with EED/PRC2 polycomb-repressive-complexes to enhance H3K27me3-mediated repression at gene loci associated with OL-differentiation inhibition and neurogenesis. Notably, BRG1 depletion decreases H3K27me3 deposition, leading to the upregulation of BMP/WNT signaling and proneurogenic genes, which suppresses OL programs. Thus, our findings reveal a hitherto unexplored spatiotemporal-specific role of BRG1 for OPC differentiation in the developing CNS and underscore a new insight into BRG1/PRC2-mediated epigenetic regulation that promotes and safeguards OL lineage commitment and differentiation.


Assuntos
Diferenciação Celular , DNA Helicases , Proteínas Nucleares , Oligodendroglia , Complexo Repressor Polycomb 2 , Remielinização , Fatores de Transcrição , Animais , DNA Helicases/metabolismo , DNA Helicases/genética , Diferenciação Celular/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Remielinização/genética , Complexo Repressor Polycomb 2/metabolismo , Complexo Repressor Polycomb 2/genética , Oligodendroglia/metabolismo , Camundongos , Histonas/metabolismo , Histonas/genética , Neurogênese/genética , Epigênese Genética , Camundongos Endogâmicos C57BL , Células Precursoras de Oligodendrócitos/metabolismo
4.
J Med Chem ; 67(6): 4819-4832, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38470227

RESUMO

The inhibition of emopamil binding protein (EBP), a sterol isomerase within the cholesterol biosynthesis pathway, promotes oligodendrocyte formation, which has been proposed as a potential therapeutic approach for treating multiple sclerosis. Herein, we describe the discovery and optimization of brain-penetrant, orally bioavailable inhibitors of EBP. A structure-based drug design approach from literature compound 1 led to the discovery of a hydantoin-based scaffold, which provided balanced physicochemical properties and potency and an improved in vitro safety profile. The long half-lives of early hydantoin-based EBP inhibitors in rodents prompted an unconventional optimization strategy, focused on increasing metabolic turnover while maintaining potency and a brain-penetrant profile. The resulting EBP inhibitor 11 demonstrated strong in vivo target engagement in the brain, as illustrated by the accumulation of EBP substrate zymostenol after repeated dosing. Furthermore, compound 11 enhanced the formation of oligodendrocytes in human cortical organoids, providing additional support for our therapeutic hypothesis.


Assuntos
Encéfalo , Hidantoínas , Humanos , Oligodendroglia/metabolismo , Desenho de Fármacos , Hidantoínas/metabolismo
5.
PLoS One ; 19(3): e0283060, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38527054

RESUMO

Acidosis is one of the hallmarks of demyelinating central nervous system (CNS) lesions in multiple sclerosis (MS). The response to acidic pH is primarily mediated by a family of G protein-coupled proton-sensing receptors: OGR1, GPR4 and TDAG8. These receptors are inactive at alkaline pH, reaching maximal activation at acidic pH. Genome-wide association studies have identified a locus within the TDAG8 gene associated with several autoimmune diseases, including MS. Accordingly, we here found that expression of TDAG8, as opposed to GPR4 or OGR1, is upregulated in MS plaques. This led us to investigate the expression of TDAG8 in oligodendrocytes using mouse and human in vitro and in vivo models. We observed significant upregulation of TDAG8 in human MO3.13 oligodendrocytes during maturation and in response to acidic conditions. However, its deficiency did not impact normal myelination in the mouse CNS, and its expression remained unaltered under demyelinating conditions in mouse organotypic cerebellar slices. Notably, our data revealed no expression of TDAG8 in primary mouse oligodendrocyte progenitor cells (OPCs), in contrast to its expression in primary human OPCs. Our investigations have revealed substantial species differences in the expression of proton-sensing receptors in oligodendrocytes, highlighting the limitations of the employed experimental models in fully elucidating the role of TDAG8 in myelination and oligodendrocyte biology. Consequently, the study does not furnish robust evidence for the role of TDAG8 in such processes. Nonetheless, our findings tentatively point towards a potential association between TDAG8 and myelination processes in humans, hinting at a potential link between TDAG8 and the pathophysiology of MS and warrants further research.


Assuntos
Esclerose Múltipla , Oligodendroglia , Receptores Acoplados a Proteínas G , Animais , Humanos , Camundongos , Estudo de Associação Genômica Ampla , Concentração de Íons de Hidrogênio , Esclerose Múltipla/genética , Doenças Neuroinflamatórias , Prótons , Receptores Acoplados a Proteínas G/metabolismo , Oligodendroglia/metabolismo
6.
Cell Rep ; 43(3): 113930, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38507412

RESUMO

Oligodendrocyte progenitor cells (OPCs) differentiate into myelin-producing cells and modulate neuronal activity. Defects in OPC development are associated with neurological diseases. N6-methyladenosine (m6A) contributes to neural development; however, the mechanism by which m6A regulates OPC development remains unclear. Here, we demonstrate that PRRC2B is an m6A reader that regulates OPC development and myelination. Nestin-Cre-mediated Prrc2b deletion affects neural stem cell self-renewal and glial differentiation. Moreover, the oligodendroglia lineage-specific deletion of Prrc2b reduces the numbers of OPCs and oligodendrocytes, causing hypomyelination and impaired motor coordination. Integrative methylated RNA immunoprecipitation sequencing, RNA sequencing, and RNA immunoprecipitation sequencing analyses identify Sox2 as the target of PRRC2B. Notably, PRRC2B, displaying separate and cooperative functions with PRRC2A, stabilizes mRNA by binding to m6A motifs in the coding sequence and 3' UTR of Sox2. In summary, we identify the posttranscriptional regulation of PRRC2B in OPC development, extending the understanding of PRRC2 family proteins and providing a therapeutic target for myelin-related disorders.


Assuntos
Células Precursoras de Oligodendrócitos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Oligodendroglia/metabolismo , Bainha de Mielina/metabolismo , Neurogênese , Diferenciação Celular/genética
7.
Glia ; 72(6): 1165-1182, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38497409

RESUMO

Oligodendrocytes (OLs) are key players in the central nervous system, critical for the formation and maintenance of the myelin sheaths insulating axons, ensuring efficient neuronal communication. In the last decade, the use of human induced pluripotent stem cells (iPSCs) has become essential for recapitulating and understanding the differentiation and role of OLs in vitro. Current methods include overexpression of transcription factors for rapid OL generation, neglecting the complexity of OL lineage development. Alternatively, growth factor-based protocols offer physiological relevance but struggle with efficiency and cell heterogeneity. To address these issues, we created a novel SOX10-P2A-mOrange iPSC reporter line to track and purify oligodendrocyte precursor cells. Using this reporter cell line, we analyzed an existing differentiation protocol and shed light on the origin of glial cell heterogeneity. Additionally, we have modified the differentiation protocol, toward enhancing reproducibility, efficiency, and terminal maturity. Our approach not only advances OL biology but also holds promise to accelerate research and translational work with iPSC-derived OLs.


Assuntos
Células-Tronco Pluripotentes Induzidas , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Linhagem da Célula , Reprodutibilidade dos Testes , Neurogênese , Oligodendroglia/metabolismo , Diferenciação Celular/fisiologia , Fatores de Transcrição SOXE/genética , Fatores de Transcrição SOXE/metabolismo
8.
Cell ; 187(8): 1955-1970.e23, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38503282

RESUMO

Characterizing somatic mutations in the brain is important for disentangling the complex mechanisms of aging, yet little is known about mutational patterns in different brain cell types. Here, we performed whole-genome sequencing (WGS) of 86 single oligodendrocytes, 20 mixed glia, and 56 single neurons from neurotypical individuals spanning 0.4-104 years of age and identified >92,000 somatic single-nucleotide variants (sSNVs) and small insertions/deletions (indels). Although both cell types accumulate somatic mutations linearly with age, oligodendrocytes accumulated sSNVs 81% faster than neurons and indels 28% slower than neurons. Correlation of mutations with single-nucleus RNA profiles and chromatin accessibility from the same brains revealed that oligodendrocyte mutations are enriched in inactive genomic regions and are distributed across the genome similarly to mutations in brain cancers. In contrast, neuronal mutations are enriched in open, transcriptionally active chromatin. These stark differences suggest an assortment of active mutagenic processes in oligodendrocytes and neurons.


Assuntos
Envelhecimento , Encéfalo , Neurônios , Oligodendroglia , Humanos , Envelhecimento/genética , Envelhecimento/patologia , Cromatina/genética , Cromatina/metabolismo , Mutação , Neurônios/metabolismo , Neurônios/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Análise da Expressão Gênica de Célula Única , Sequenciamento Completo do Genoma , Encéfalo/metabolismo , Encéfalo/patologia , Polimorfismo de Nucleotídeo Único , Mutação INDEL , Bancos de Espécimes Biológicos , Células Precursoras de Oligodendrócitos/metabolismo , Células Precursoras de Oligodendrócitos/patologia
9.
Front Immunol ; 15: 1331210, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38464529

RESUMO

Introduction: Microglia and macrophages can influence the evolution of myelin lesions through the production of extracellular vesicles (EVs). While microglial EVs promote in vitro differentiation of oligodendrocyte precursor cells (OPCs), whether EVs derived from macrophages aid or limit OPC maturation is unknown. Methods: Immunofluorescence analysis for the myelin protein MBP was employed to evaluate the impact of EVs from primary rat macrophages on cultured OPC differentiation. Raman spectroscopy and liquid chromatography-mass spectrometry was used to define the promyelinating lipid components of myelin EVs obtained in vitro and isolated from human plasma. Results and discussion: Here we show that macrophage-derived EVs do not promote OPC differentiation, and those released from macrophages polarized towards an inflammatory state inhibit OPC maturation. However, their lipid cargo promotes OPC maturation in a similar manner to microglial EVs. We identify the promyelinating endocannabinoids anandamide and 2-arachidonoylglycerol in EVs released by both macrophages and microglia in vitro and circulating in human plasma. Analysis of OPC differentiation in the presence of the endocannabinoid receptor antagonists SR141716A and AM630 reveals a key role of vesicular endocannabinoids in OPC maturation. From this study, EV-associated endocannabinoids emerge as important mediators in microglia/macrophage-oligodendrocyte crosstalk, which may be exploited to enhance myelin repair.


Assuntos
Vesículas Extracelulares , Microglia , Ratos , Animais , Humanos , Microglia/metabolismo , Endocanabinoides/metabolismo , Macrófagos , Oligodendroglia/metabolismo
10.
Proc Natl Acad Sci U S A ; 121(12): e2307250121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38483990

RESUMO

Myelination of neuronal axons is essential for nervous system development. Myelination requires dramatic cytoskeletal dynamics in oligodendrocytes, but how actin is regulated during myelination is poorly understood. We recently identified serum response factor (SRF)-a transcription factor known to regulate expression of actin and actin regulators in other cell types-as a critical driver of myelination in the aged brain. Yet, a major gap remains in understanding the mechanistic role of SRF in oligodendrocyte lineage cells. Here, we show that SRF is required cell autonomously in oligodendrocytes for myelination during development. Combining ChIP-seq with RNA-seq identifies SRF-target genes in oligodendrocyte precursor cells and oligodendrocytes that include actin and other key cytoskeletal genes. Accordingly, SRF knockout oligodendrocytes exhibit dramatically reduced actin filament levels early in differentiation, consistent with its role in actin-dependent myelin sheath initiation. Surprisingly, oligodendrocyte-restricted loss of SRF results in upregulation of gene signatures associated with aging and neurodegenerative diseases. Together, our findings identify SRF as a transcriptional regulator that controls the expression of cytoskeletal genes required in oligodendrocytes for myelination. This study identifies an essential pathway regulating oligodendrocyte biology with high relevance to brain development, aging, and disease.


Assuntos
Actinas , Fator de Resposta Sérica , Actinas/genética , Actinas/metabolismo , Fator de Resposta Sérica/genética , Fator de Resposta Sérica/metabolismo , Oligodendroglia/metabolismo , Bainha de Mielina/genética , Bainha de Mielina/metabolismo , Citoesqueleto/genética , Diferenciação Celular/genética
11.
J Neuroinflammation ; 21(1): 69, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38509618

RESUMO

Microglial Na/H exchanger-1 (NHE1) protein, encoded by Slc9a1, plays a role in white matter demyelination of ischemic stroke brains. To explore underlying mechanisms, we conducted single cell RNA-seq transcriptome analysis in conditional Slc9a1 knockout (cKO) and wild-type (WT) mouse white matter tissues at 3 days post-stroke. Compared to WT, Nhe1 cKO brains expanded a microglial subgroup with elevated transcription of white matter myelination genes including Spp1, Lgals3, Gpnmb, and Fabp5. This subgroup also exhibited more acidic pHi and significantly upregulated CREB signaling detected by ingenuity pathway analysis and flow cytometry. Moreover, the Nhe1 cKO white matter tissues showed enrichment of a corresponding oligodendrocyte subgroup, with pro-phagocytosis and lactate shuffling gene expression, where activated CREB signaling is a likely upstream regulator. These findings demonstrate that attenuation of NHE1-mediated H+ extrusion acidifies microglia/macrophage and may underlie the stimulation of CREB1 signaling, giving rise to restorative microglia-oligodendrocyte interactions for remyelination.


Assuntos
Encéfalo , Microglia , Trocador 1 de Sódio-Hidrogênio , Animais , Camundongos , Encéfalo/metabolismo , Receptor 1 de Quimiocina CX3C/metabolismo , Macrófagos/metabolismo , Microglia/metabolismo , Oligodendroglia/metabolismo , Transdução de Sinais/genética , Trocador 1 de Sódio-Hidrogênio/metabolismo
12.
J Neurosci ; 44(13)2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38395617

RESUMO

Myelinating oligodendrocytes die in human disease and early in aging. Despite this, the mechanisms that underly oligodendrocyte death are not resolved and it is also not clear whether these mechanisms change as oligodendrocyte lineage cells are undergoing differentiation and maturation. Here, we used a combination of intravital imaging, single-cell ablation, and cuprizone-mediated demyelination, in both female and male mice, to discover that oligodendrocyte maturation dictates the dynamics and mechanisms of cell death. After single-cell phototoxic damage, oligodendrocyte precursor cells underwent programmed cell death within hours, differentiating oligodendrocytes died over several days, while mature oligodendrocytes took weeks to die. Importantly cells at each maturation stage all eventually died but did so with drastically different temporal dynamics and morphological features. Consistent with this, cuprizone treatment initiated a caspase-3-dependent form of rapid cell death in differentiating oligodendrocytes, while mature oligodendrocytes never activated this executioner caspase. Instead, mature oligodendrocytes exhibited delayed cell death which was marked by DNA damage and disruption in poly-ADP-ribose subcellular localization. Thus, oligodendrocyte maturation plays a key role in determining the mechanism of death a cell undergoes in response to the same insult. This means that oligodendrocyte maturation is important to consider when designing strategies for preventing cell death and preserving myelin while also enhancing the survival of new oligodendrocytes in demyelinating conditions.


Assuntos
Cuprizona , Doenças Desmielinizantes , Humanos , Camundongos , Masculino , Feminino , Animais , Cuprizona/toxicidade , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/metabolismo , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Apoptose/fisiologia , Diferenciação Celular , Camundongos Endogâmicos C57BL
13.
Adv Drug Deliv Rev ; 207: 115218, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38403255

RESUMO

Interest in myelin and its roles in almost all brain functions has been greatly increasing in recent years, leading to countless new studies on myelination, as a dominant process in the development of cognitive functions. Here, we explore the unique role myelin plays in the central nervous system and specifically discuss the results of altered myelination in neurodevelopmental disorders. We present parallel developmental trajectories involving myelination that correlate with the onset of cognitive impairment in neurodevelopmental disorders and discuss the key challenges in the treatment of these chronic disorders. Recent developments in drug repurposing and nano/micro particle-based therapies are reviewed as a possible pathway to circumvent some of the main hurdles associated with early intervention, including patient's adherence and compliance, side effects, relapse, and faster route to possible treatment of these disorders. The strategy of drug encapsulation overcomes drug solubility and metabolism, with the possibility of drug targeting to a specific compartment, reducing side effects upon systemic administration.


Assuntos
Bainha de Mielina , Transtornos do Neurodesenvolvimento , Humanos , Bainha de Mielina/metabolismo , Transtornos do Neurodesenvolvimento/tratamento farmacológico , Transtornos do Neurodesenvolvimento/metabolismo , Sistemas de Liberação de Medicamentos , Oligodendroglia/metabolismo
14.
Mov Disord ; 39(4): 723-728, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38357858

RESUMO

BACKGROUND: The architecture and composition of glial (GCI) and neuronal (NCI) α-synuclein inclusions observed in multiple system atrophy (MSA) remain to be precisely defined to better understand the disease. METHODS: Here, we used stochastic optical reconstruction microscopy (STORM) to characterize the nanoscale organization of glial (GCI) and neuronal (NCI) α-synuclein inclusions in cryopreserved brain sections from MSA patients. RESULTS: STORM revealed a dense cross-linked internal structure of α-synuclein in all GCI and NCI. The internal architecture of hyperphosphorylated α-synuclein (p-αSyn) inclusions was similar in glial and neuronal cells, suggesting a common aggregation mechanism. A similar sequence of p-αSyn stepwise intracellular aggregation was defined in oligodendrocytes and neurons, starting from the perinuclear area and growing inside the cells. Consistent with this hypothesis, we found a higher mitochondrial density in GCI and NCI compared to oligodendrocytes and neurons from unaffected donors (P < 0.01), suggesting an active recruitment of the organelles during the aggregation process. CONCLUSIONS: These first STORM images of GCI and NCI suggest stepwise α-synuclein aggregation in MSA. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Assuntos
Corpos de Inclusão , Atrofia de Múltiplos Sistemas , Neurônios , alfa-Sinucleína , Humanos , Atrofia de Múltiplos Sistemas/patologia , Atrofia de Múltiplos Sistemas/metabolismo , alfa-Sinucleína/metabolismo , Corpos de Inclusão/patologia , Corpos de Inclusão/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Feminino , Idoso , Masculino , Pessoa de Meia-Idade , Encéfalo/patologia , Encéfalo/metabolismo , Neuroglia/metabolismo , Neuroglia/patologia , Oligodendroglia/patologia , Oligodendroglia/metabolismo , Microscopia/métodos
15.
Int J Mol Sci ; 25(3)2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38338724

RESUMO

Multiple sclerosis (MS) is an autoimmune and inflammatory disorder affecting the central nervous system whose cause is still largely unknown. Oligodendrocyte degeneration results in demyelination of axons, which can eventually be repaired by a mechanism called remyelination. Prevention of demyelination and the pharmacological support of remyelination are two promising strategies to ameliorate disease progression in MS patients. The cuprizone model is commonly employed to investigate oligodendrocyte degeneration mechanisms or to explore remyelination pathways. During the last decades, several different protocols have been applied, and all have their pros and cons. This article intends to offer guidance for conducting pre-clinical trials using the cuprizone model in mice, focusing on discovering new treatment approaches to prevent oligodendrocyte degeneration or enhance remyelination.


Assuntos
Doenças Desmielinizantes , Esclerose Múltipla , Remielinização , Humanos , Camundongos , Animais , Cuprizona , Bainha de Mielina/metabolismo , Doenças Desmielinizantes/metabolismo , Oligodendroglia/metabolismo , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/metabolismo , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças
16.
Sci Adv ; 10(6): eadk3931, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38324685

RESUMO

Maldevelopment of oligodendroglia underlies neural developmental disorders such as leukodystrophy. Precise regulation of the activity of specific transcription factors (TFs) by various posttranslational modifications (PTMs) is required to ensure proper oligodendroglial development and myelination. However, the role of ubiquitination of these TFs during oligodendroglial development is yet unexplored. Here, we find that RNF220, a known leukodystrophy-related E3 ubiquitin ligase, is required for oligodendroglial development. RNF220 depletion in oligodendrocyte lineage cells impedes oligodendrocyte progenitor cell proliferation, differentiation, and (re)myelination, which consequently leads to learning and memory defects. Mechanistically, RNF220 targets Olig1/2 for K63-linked polyubiquitination and stabilization during oligodendroglial development. Furthermore, in a knock-in mouse model of leukodystrophy-related RNF220R365Q mutation, the ubiquitination and stabilization of Olig proteins are deregulated in oligodendroglial cells. This results in pathomimetic oligodendroglial developmental defects, impaired myelination, and abnormal behaviors. Together, our evidence provides an alternative insight into PTMs of oligodendroglial TFs and how this essential process may be implicated in the etiology of leukodystrophy.


Assuntos
Doenças Desmielinizantes , Neurogênese , Camundongos , Animais , Diferenciação Celular/genética , Ubiquitinação , Oligodendroglia/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Doenças Desmielinizantes/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
17.
Sci Rep ; 14(1): 4091, 2024 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-38374232

RESUMO

In the central nervous system, oligodendrocyte precursor cells (OPCs) proliferate and differentiate into myelinating oligodendrocytes throughout life, allowing for ongoing myelination and myelin repair. With age, differentiation efficacy decreases and myelin repair fails; therefore, recent therapeutic efforts have focused on enhancing differentiation. Many cues are thought to regulate OPC differentiation, including neuronal activity, which OPCs can sense and respond to via their voltage-gated ion channels and glutamate receptors. However, OPCs' density of voltage-gated ion channels and glutamate receptors differs with age and brain region, and correlates with their proliferation and differentiation potential, suggesting that OPCs exist in different functional cell states, and that age-associated states might underlie remyelination failure. Here, we use whole-cell patch-clamp to investigate whether clemastine and metformin, two pro-remyelination compounds, alter OPC membrane properties and promote a specific OPC state. We find that clemastine and metformin extend the window of NMDAR surface expression, promoting an NMDAR-rich OPC state. Our findings highlight a possible mechanism for the pro-remyelinating action of clemastine and metformin, and suggest that OPC states can be modulated as a strategy to promote myelin repair.


Assuntos
Metformina , Células Precursoras de Oligodendrócitos , Células Precursoras de Oligodendrócitos/metabolismo , Clemastina , Receptores de N-Metil-D-Aspartato/metabolismo , Metformina/farmacologia , Metformina/metabolismo , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Diferenciação Celular/fisiologia
18.
Cell ; 187(4): 814-830.e23, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38364788

RESUMO

Myelin, the insulating sheath that surrounds neuronal axons, is produced by oligodendrocytes in the central nervous system (CNS). This evolutionary innovation, which first appears in jawed vertebrates, enabled rapid transmission of nerve impulses, more complex brains, and greater morphological diversity. Here, we report that RNA-level expression of RNLTR12-int, a retrotransposon of retroviral origin, is essential for myelination. We show that RNLTR12-int-encoded RNA binds to the transcription factor SOX10 to regulate transcription of myelin basic protein (Mbp, the major constituent of myelin) in rodents. RNLTR12-int-like sequences (which we name RetroMyelin) are found in all jawed vertebrates, and we further demonstrate their function in regulating myelination in two different vertebrate classes (zebrafish and frogs). Our study therefore suggests that retroviral endogenization played a prominent role in the emergence of vertebrate myelin.


Assuntos
Bainha de Mielina , Retroelementos , Animais , Expressão Gênica , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Retroelementos/genética , RNA/metabolismo , Peixe-Zebra/genética , Anuros
19.
Neurochem Res ; 49(4): 1105-1120, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38289520

RESUMO

Reduced myelin stability observed in the early stages of Alzheimer's disease leads to spatial learning and memory impairment. Exercise has been shown to protect nerves, reduce the risk of Alzheimer's disease, and strengthen synaptic connectivity. However, the underlying mechanisms of how exercise can promote myelin repair and coordinate inflammation and proliferation are still uncertain. In this study, we conducted histological and biochemical assays of cortical lysates after behavioral testing to detect pathological changes, myelin sheath thickness, and mRNA and protein levels. It is notable that D-galactose model mice exhibited elevated miRNA-34a levels, overactive astrocytes, decreased myelin staining scores, increased apoptosis, and decreased synaptic plasticity in the brain. Significantly, after eight weeks of exercise, we observed improvements in LFB scores, NeuN( +) neuron counts, and myelin basic protein (MBP) expression. Additionally, exercise promoted the expression of oligodendrocyte markers Olig2 and PDFGR-α associated with brain proliferation, and improved spatial cognitive function. Furthermore, it decreased the inflammation caused by astrocyte secretions (TNF-α, Cox-2, CXCL2). Interestingly, we also observed downregulation of miR-34a and activation of the TAN1/PI3K/CREB signaling pathway. Our data shed light on a previously unsuspected mechanism by which exercise reduces miR-34a levels and protects neuronal function and survival by preventing excessive demyelination and inflammatory infiltration in the CNS.


Assuntos
Doença de Alzheimer , MicroRNAs , Animais , Camundongos , Doença de Alzheimer/metabolismo , Astrócitos/metabolismo , Inflamação/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Bainha de Mielina/metabolismo , Doenças Neuroinflamatórias , Oligodendroglia/metabolismo
20.
Glia ; 72(4): 809-827, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38205694

RESUMO

Recent findings highlight myelin breakdown as a decisive early event in Alzheimer's Disease (AD) acting as aggravating factor of its progression. However, it is still unclear whether myelin loss is attributed to increased oligodendrocyte vulnerability, reduced repairing capacity or toxic stimuli. In the present study, we sought to clarify the starting point of myelin disruption accompanied with Oligodendrocyte Progenitor Cell (OPC) elimination in the brain of the 5xFAD mouse model of AD at 6 months of age in Dentate Gyrus of the hippocampus in relation to neurotrophin system. Prominent inflammation presence was detected since the age of 6 months playing a key role in myelin disturbance and AD progression. Expression analysis of neurotrophin receptors in OPCs was performed to identify new targets that could increase myelination in health and disease. OPCs in both control and 5xFAD mice express TrkB, TrkC and p75 receptors but not TrkA. Brain-derived neurotrophic factor (BDNF) that binds to TrkB receptor is well-known about its pro-myelination effect, promoting oligodendrocytes proliferation and differentiation, so we focused our investigation on its effects in OPCs under neurodegenerative conditions. Our in vitro results showed that BDNF rescues OPCs from death and promotes their proliferation and differentiation in presence of the toxic Amyloid-ß 1-42. Collectively, our results indicate that BDNF possess an additional neuroprotective role through its actions on oligodendrocytic component and its use could be proposed as a drug-based myelin-enhancing strategy, complementary to amyloid and tau centered therapies in AD.


Assuntos
Doença de Alzheimer , Bainha de Mielina , Camundongos , Animais , Bainha de Mielina/metabolismo , Doença de Alzheimer/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Encéfalo/metabolismo , Oligodendroglia/metabolismo
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