Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
2.
Eur Arch Psychiatry Clin Neurosci ; 270(4): 413-424, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31552495

RESUMO

In schizophrenia, decreased hippocampal volume, reduced oligodendrocyte numbers in hippocampal cornu ammonis (CA) subregions and reduced neuron number in the dentate gyrus have been reported; reduced oligodendrocyte numbers were significantly related to cognitive deficits. The hippocampus is involved in cognitive functions and connected to the hypothalamus, anterior thalamus, and cingulate cortex, forming the Papez circuit, and to the mediodorsal thalamus. The relationship between the volume of these interconnected regions and oligodendrocyte and neuron numbers in schizophrenia is unknown. Therefore, we used stepwise logistic regression with subsequent multivariate stepwise linear regression and bivariate correlation to analyze oligodendrocyte and neuron numbers in the posterior hippocampal subregions CA1, CA2/3, CA4, dentate gyrus, and subiculum and volumes of the hippocampal CA region, cingulum, anterior and mediodorsal thalamus and hypothalamus in postmortem brains of 10 schizophrenia patients and 11 age- and gender-matched healthy controls. Stepwise logistic regression identified the following predictors for diagnosis, in order of inclusion: (1) oligodendrocyte number in CA4, (2) hypothalamus volume, (3) oligodendrocyte number in CA2/3, and (4) mediodorsal thalamus volume. Subsequent stepwise linear regression analyses identified the following predictors: (1) for oligodendrocyte number in CA4: (a) oligodendrocyte number in CA2/3, (b) diagnostic group, (c) hypothalamus volume, and (d) neurons in posterior subiculum; (2) for hypothalamus volume: (a) mediodorsal thalamus volume; (3) for oligodendrocyte number in CA2/3: oligodendrocyte number (a) in posterior CA4 and (b) in posterior subiculum; (4) for mediodorsal thalamus volume: volumes of (a) anterior thalamus and (b) hippocampal CA. In conclusion, we found a positive relationship between hippocampal oligodendrocyte number and the volume of the hypothalamus, a brain region connected to the hippocampus, which is important for cognition.


Assuntos
Hipocampo/patologia , Hipotálamo/patologia , Rede Nervosa/patologia , Oligodendroglia/citologia , Esquizofrenia/patologia , Tálamo/patologia , Adulto , Autopsia , Feminino , Hipocampo/citologia , Humanos , Hipotálamo/citologia , Masculino , Pessoa de Meia-Idade , Esquizofrenia/diagnóstico
3.
J Neurosci ; 35(4): 1606-16, 2015 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-25632136

RESUMO

The atrophy of skeletal muscles in patients with Krabbe disease is a major debilitating manifestation that worsens their quality of life and limits the clinical efficacy of current therapies. The pathogenic mechanism triggering muscle wasting is unknown. This study examined structural, functional, and metabolic changes conducive to muscle degeneration in Krabbe disease using the murine (twitcher mouse) and canine [globoid cell leukodystrophy (GLD) dog] models. Muscle degeneration, denervation, neuromuscular [neuromuscular junction (NMJ)] abnormalities, and axonal death were investigated using the reporter transgenic twitcher-Thy1.1-yellow fluorescent protein mouse. We found that mutant muscles had significant numbers of smaller-sized muscle fibers, without signs of regeneration. Muscle growth was slow and weak in twitcher mice, with decreased maximum force. The NMJ had significant levels of activated caspase-3 but limited denervation. Mutant NMJ showed reduced surface areas and lower volumes of presynaptic terminals, with depressed nerve control, increased miniature endplate potential (MEPP) amplitude, decreased MEPP frequency, and increased rise and decay rate constants. Twitcher and GLD dog muscles had significant capacity to store psychosine, the neurotoxin that accumulates in Krabbe disease. Mechanistically, muscle defects involved the inactivation of the Akt pathway and activation of the proteasome pathway. Our work indicates that muscular dysfunction in Krabbe disease is compounded by a pathogenic mechanism involving at least the failure of NMJ function, activation of proteosome degradation, and a reduction of the Akt pathway. Akt, which is key for muscle function, may constitute a novel target to complement in therapies for Krabbe disease.


Assuntos
Leucodistrofia de Células Globoides/complicações , Leucodistrofia de Células Globoides/patologia , Doenças Neuromusculares/etiologia , Doenças Neuromusculares/metabolismo , Animais , Animais Recém-Nascidos , Axônios/metabolismo , Axônios/patologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Cães , Galactosilceramidase/genética , Regulação da Expressão Gênica/genética , Leucodistrofia de Células Globoides/genética , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células Musculares/efeitos dos fármacos , Células Musculares/metabolismo , Contração Muscular/genética , Músculo Esquelético/crescimento & desenvolvimento , Doenças Neuromusculares/patologia , Psicosina/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Potenciais Sinápticos/efeitos dos fármacos , Potenciais Sinápticos/genética
4.
J Neurosci Res ; 94(11): 1031-6, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27638588

RESUMO

The presence of life-threatening neurological symptoms in more than two-thirds of lysosomal storage diseases (LSDs) underscores how vulnerable the nervous system is to lysosomal failure. Neurological dysfunction in LSDs has historically been attributed to the disruption of neuronal and glial homeostasis resulting from the progressive jamming of the endosomal/lysosomal pathway. In neurons, a dysfunctional endosomal-lysosomal system can elicit dire consequences. Given that neurons are largely postmitotic after birth, one can clearly understand that the inability of these cells to proliferate obliterates any possibility of diluting stored lysosomal material by means of cellular division. At its most advanced stage, this situation constitutes a terminal factor in neuronal life, resulting in cell death. However, synaptic deficits in the absence of classical neuronal cell death appear to be common features during the early stages in many LSDs, particularly sphingolipidoses. In essence, failure of synapses to convey their messages, even without major structural damage to the neuronal bodies, is a form of physiological death. This concept of dying-back neuropathology is highly relevant not only for understanding the dynamics of the neurological decline in these diseases, but, more importantly; it might also constitute an important target for molecular therapies to protect perhaps the "Achilles" point in the entire physiological architecture of the brain, thus avoiding an irreversible journey to neuronal demise. © 2016 Wiley Periodicals, Inc.


Assuntos
Sistema Nervoso/patologia , Neurônios/patologia , Esfingolipidoses/patologia , Sinapses/fisiologia , Animais , Humanos , Modelos Neurológicos
5.
J Pathol ; 232(5): 509-21, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24415155

RESUMO

Demyelination is a major contributor to the general decay of neural functions in children with Krabbe disease. However, recent reports have indicated a significant involvement of neurons and axons in the neuropathology of the disease. In this study, we have investigated the nature of cellular inclusions in the Krabbe brain. Brain samples from the twitcher mouse model for Krabbe disease and from patients affected with the infantile and late-onset forms of the disease were examined for the presence of neuronal inclusions. Our experiments demonstrated the presence of cytoplasmic aggregates of thioflavin-S-reactive material in both human and murine mutant brains. Most of these inclusions were associated with neurons. A few inclusions were detected to be associated with microglia and none were associated with astrocytes or oligodendrocytes. Thioflavin-S-reactive inclusions increased in abundance, paralleling the development of neurological symptoms, and distributed throughout the twitcher brain in areas of major involvement in cognition and motor functions. Electron microscopy confirmed the presence of aggregates of stereotypic ß-sheet folded proteinaceous material. Immunochemical analyses identified the presence of aggregated forms of α-synuclein and ubiquitin, proteins involved in the formation of Lewy bodies in Parkinson's disease and other neurodegenerative conditions. In vitro assays demonstrated that psychosine, the neurotoxic sphingolipid accumulated in Krabbe disease, accelerated the fibrillization of α-synuclein. This study demonstrates the occurrence of neuronal deposits of fibrillized proteins including α-synuclein, identifying Krabbe disease as a new α-synucleinopathy.


Assuntos
Encéfalo/metabolismo , Leucodistrofia de Células Globoides/metabolismo , Corpos de Lewy/metabolismo , Neurônios/metabolismo , alfa-Sinucleína/metabolismo , Animais , Benzotiazóis , Encéfalo/fisiopatologia , Encéfalo/ultraestrutura , Estudos de Casos e Controles , Cognição , Modelos Animais de Doenças , Corantes Fluorescentes , Humanos , Leucodistrofia de Células Globoides/genética , Leucodistrofia de Células Globoides/patologia , Leucodistrofia de Células Globoides/fisiopatologia , Leucodistrofia de Células Globoides/psicologia , Corpos de Lewy/ultraestrutura , Camundongos , Atividade Motora , Mutação , Neurônios/ultraestrutura , Psicosina/metabolismo , Tiazóis , alfa-Sinucleína/genética
6.
J Neurosci ; 33(24): 10048-56, 2013 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-23761900

RESUMO

Loss of function of galactosylceramidase lysosomal activity causes demyelination and vulnerability of various neuronal populations in Krabbe disease. Psychosine, a lipid-raft-associated sphingolipid that accumulates in this disease, is thought to trigger these abnormalities. Myelin-free in vitro analyses showed that psychosine inhibited fast axonal transport through the activation of axonal PP1 and GSK3ß in the axon. Abnormal levels of activated GSK3ß and abnormally phosphorylated kinesin light chains were found in nerve samples from a mouse model of Krabbe disease. Administration of GSK3ß inhibitors significantly ameliorated transport defects in vitro and in vivo in peripheral axons of the mutant mouse. This study identifies psychosine as a pathogenic sphingolipid able to block fast axonal transport and is the first to provide a molecular mechanism underlying dying-back degeneration in this genetic leukodystrophy.


Assuntos
Transporte Axonal/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/metabolismo , Leucodistrofia de Células Globoides/patologia , Proteínas Motores Moleculares/metabolismo , Neurônios/patologia , Psicosina/farmacologia , Análise de Variância , Animais , Animais Recém-Nascidos , Células Cultivadas , Córtex Cerebral/patologia , Modelos Animais de Doenças , Embrião de Mamíferos , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/genética , Glicogênio Sintase Quinase 3 beta , Leucodistrofia de Células Globoides/tratamento farmacológico , Leucodistrofia de Células Globoides/genética , Microdomínios da Membrana/efeitos dos fármacos , Microdomínios da Membrana/enzimologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Microscopia Eletrônica de Transmissão , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/ultraestrutura , Nervo Isquiático/patologia , Fatores de Tempo
8.
Nat Neurosci ; 27(8): 1468-1474, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38937583

RESUMO

Age-related myelin damage induces inflammatory responses, yet its involvement in Alzheimer's disease remains uncertain, despite age being a major risk factor. Using a mouse model of Alzheimer's disease, we found that amyloidosis itself triggers age-related oligodendrocyte and myelin damage. Mechanistically, CD8+ T cells promote the progressive accumulation of abnormally interferon-activated microglia that display myelin-damaging activity. Thus, our data suggest that immune responses against myelinating oligodendrocytes may contribute to neurodegenerative diseases with amyloidosis.


Assuntos
Doença de Alzheimer , Amiloidose , Modelos Animais de Doenças , Microglia , Bainha de Mielina , Animais , Microglia/patologia , Microglia/metabolismo , Microglia/imunologia , Bainha de Mielina/patologia , Bainha de Mielina/metabolismo , Camundongos , Amiloidose/patologia , Doença de Alzheimer/patologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/imunologia , Linfócitos T CD8-Positivos/imunologia , Camundongos Transgênicos , Oligodendroglia/patologia , Oligodendroglia/metabolismo , Camundongos Endogâmicos C57BL
9.
Nat Commun ; 14(1): 4115, 2023 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-37433806

RESUMO

Understanding the complexity of cellular function within a tissue necessitates the combination of multiple phenotypic readouts. Here, we developed a method that links spatially-resolved gene expression of single cells with their ultrastructural morphology by integrating multiplexed error-robust fluorescence in situ hybridization (MERFISH) and large area volume electron microscopy (EM) on adjacent tissue sections. Using this method, we characterized in situ ultrastructural and transcriptional responses of glial cells and infiltrating T-cells after demyelinating brain injury in male mice. We identified a population of lipid-loaded "foamy" microglia located in the center of remyelinating lesion, as well as rare interferon-responsive microglia, oligodendrocytes, and astrocytes that co-localized with T-cells. We validated our findings using immunocytochemistry and lipid staining-coupled single-cell RNA sequencing. Finally, by integrating these datasets, we detected correlations between full-transcriptome gene expression and ultrastructural features of microglia. Our results offer an integrative view of the spatial, ultrastructural, and transcriptional reorganization of single cells after demyelinating brain injury.


Assuntos
Lesões Encefálicas , Transcriptoma , Masculino , Animais , Camundongos , Hibridização in Situ Fluorescente , Microscopia Eletrônica , Lesões Encefálicas/genética , Lipídeos
10.
Neurobiol Dis ; 46(2): 325-35, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22326830

RESUMO

Patients with Krabbe disease, a genetic demyelinating syndrome caused by deficiency of galactosyl-ceramidase and the resulting accumulation of galactosyl-sphingolipids, develop signs of a dying-back axonopathy compounded by a deficiency of large-caliber axons. Here, we show that axonal caliber in Twitcher mice, an animal model for Krabbe disease, is impaired in peripheral axons and is accompanied by a progressive reduction in the abundance and phosphorylation of the three neurofilament (NF) subunits. These changes correlate with an increase in the density of NFs per cross-sectional area in numerous mutant peripheral axons and abnormal increases in the activity of two serine/threonine phosphatases (PP1 and PP2A) in mutant tissue. Similarly, acutely isolated mutant cortical neurons show abnormal phosphorylation of NFs. Psychosine, the neurotoxin accumulated in Krabbe disease, was sufficient to induce abnormal dephosphorylation of NF subunits in a normal motor neuron cell line as well as in acutely isolated normal cortical neurons. This in vitro effect was mediated by PP1 and PP2A, which specifically dephosphorylated NFs. These results demonstrate that the reduced caliber observed in some axons in Krabbe disease involves abnormal dephosphorylation of NFs. We propose that a psychosine-driven pathogenic mechanism through deregulated phosphotransferase activities may be involved in this process.


Assuntos
Proteínas de Neurofilamentos/metabolismo , Proteína Fosfatase 1/fisiologia , Proteína Fosfatase 2/fisiologia , Psicosina/farmacologia , Animais , Células Cultivadas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Bainha de Mielina/genética , Bainha de Mielina/patologia , Bainha de Mielina/fisiologia , Inibição Neural/genética , Proteínas de Neurofilamentos/antagonistas & inibidores , Neurotoxinas/farmacologia , Fosforilação/fisiologia , Regulação para Cima/genética
11.
Nat Neurosci ; 25(11): 1446-1457, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36280798

RESUMO

A hallmark of nervous system aging is a decline of white matter volume and function, but the underlying mechanisms leading to white matter pathology are unknown. In the present study, we found age-related alterations of oligodendrocyte cell state with a reduction in total oligodendrocyte density in aging murine white matter. Using single-cell RNA-sequencing, we identified interferon (IFN)-responsive oligodendrocytes, which localize in proximity to CD8+ T cells in aging white matter. Absence of functional lymphocytes decreased the number of IFN-responsive oligodendrocytes and rescued oligodendrocyte loss, whereas T-cell checkpoint inhibition worsened the aging response. In addition, we identified a subpopulation of lymphocyte-dependent, IFN-responsive microglia in the vicinity of the CD8+ T cells in aging white matter. In summary, we provide evidence that CD8+ T-cell-induced, IFN-responsive oligodendrocytes and microglia are important modifiers of white matter aging.


Assuntos
Microglia , Substância Branca , Animais , Camundongos , Linfócitos T CD8-Positivos , Interferons , Oligodendroglia
12.
J Exp Med ; 218(10)2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34424266

RESUMO

Upon demyelinating injury, microglia orchestrate a regenerative response that promotes myelin repair, thereby restoring rapid signal propagation and protecting axons from further damage. Whereas the essential phagocytic function of microglia for remyelination is well known, the underlying metabolic pathways required for myelin debris clearance are poorly understood. Here, we show that cholesterol esterification in male mouse microglia/macrophages is a necessary adaptive response to myelin debris uptake and required for the generation of lipid droplets upon demyelinating injury. When lipid droplet biogenesis is defective, innate immune cells do not resolve, and the regenerative response fails. We found that triggering receptor expressed on myeloid cells 2 (TREM2)-deficient mice are unable to adapt to excess cholesterol exposure, form fewer lipid droplets, and build up endoplasmic reticulum (ER) stress. Alleviating ER stress in TREM2-deficient mice restores lipid droplet biogenesis and resolves the innate immune response. Thus, we conclude that TREM2-dependent formation of lipid droplets constitute a protective response required for remyelination to occur.


Assuntos
Gotículas Lipídicas/metabolismo , Glicoproteínas de Membrana/metabolismo , Fagócitos/fisiologia , Receptores Imunológicos/metabolismo , Remielinização/fisiologia , Animais , Colesterol/metabolismo , Estresse do Retículo Endoplasmático , Esterificação , Glicoproteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/metabolismo , Microglia/patologia , Biossíntese de Proteínas/fisiologia , Receptores Imunológicos/genética , Esterol O-Aciltransferase/genética
13.
Cell Rep ; 37(4): 109898, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34706241

RESUMO

After demyelinating injury of the central nervous system, resolution of the mounting acute inflammation is crucial for the initiation of a regenerative response. Here, we aim to identify fatty acids and lipid mediators that govern the balance of inflammatory reactions within demyelinating lesions. Using lipidomics, we identify bioactive lipids in the resolution phase of inflammation with markedly elevated levels of n-3 polyunsaturated fatty acids. Using fat-1 transgenic mice, which convert n-6 fatty acids to n-3 fatty acids, we find that reduction of the n-6/n-3 ratio decreases the phagocytic infiltrate. In addition, we observe accelerated decline of microglia/macrophages and enhanced generation of oligodendrocytes in aged mice when n-3 fatty acids are shuttled to the brain. Thus, n-3 fatty acids enhance lesion recovery and may, therefore, provide the basis for pro-regenerative medicines of demyelinating diseases in the central nervous system.


Assuntos
Envelhecimento , Encéfalo/metabolismo , Doenças Desmielinizantes/metabolismo , Ácidos Graxos Ômega-3/metabolismo , Ácidos Graxos Ômega-6/metabolismo , Oligodendroglia/metabolismo , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Doenças Desmielinizantes/genética , Ácidos Graxos Ômega-3/genética , Ácidos Graxos Ômega-6/genética , Lipidômica , Camundongos , Camundongos Knockout , Microglia/metabolismo
14.
Nat Metab ; 3(2): 211-227, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33619376

RESUMO

Proregenerative responses are required for the restoration of nervous-system functionality in demyelinating diseases such as multiple sclerosis (MS). Yet, the limiting factors responsible for poor CNS repair are only partially understood. Here, we test the impact of a Western diet (WD) on phagocyte function in a mouse model of demyelinating injury that requires microglial innate immune function for a regenerative response to occur. We find that WD feeding triggers an ageing-related, dysfunctional metabolic response that is associated with impaired myelin-debris clearance in microglia, thereby impairing lesion recovery after demyelination. Mechanistically, we detect enhanced transforming growth factor beta (TGFß) signalling, which suppresses the activation of the liver X receptor (LXR)-regulated genes involved in cholesterol efflux, thereby inhibiting phagocytic clearance of myelin and cholesterol. Blocking TGFß or promoting triggering receptor expressed on myeloid cells 2 (TREM2) activity restores microglia responsiveness and myelin-debris clearance after demyelinating injury. Thus, we have identified a druggable microglial immune checkpoint mechanism regulating the microglial response to injury that promotes remyelination.


Assuntos
Doenças Desmielinizantes/imunologia , Doenças Desmielinizantes/metabolismo , Dieta , Imunidade Inata/imunologia , Fator de Crescimento Transformador beta/metabolismo , Envelhecimento/metabolismo , Animais , Colesterol/metabolismo , Dieta Ocidental , Receptores X do Fígado , Lisofosfatidilcolinas/farmacologia , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Bainha de Mielina/metabolismo , Fagócitos/metabolismo , Receptores Imunológicos/metabolismo
15.
Neuron ; 109(7): 1100-1117.e10, 2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33606969

RESUMO

Aging results in gray and white matter degeneration, but the specific microglial responses are unknown. Using single-cell RNA sequencing from white and gray matter separately, we identified white matter-associated microglia (WAMs), which share parts of the disease-associated microglia (DAM) gene signature and are characterized by activation of genes implicated in phagocytic activity and lipid metabolism. WAMs depend on triggering receptor expressed on myeloid cells 2 (TREM2) signaling and are aging dependent. In the aged brain, WAMs form independent of apolipoprotein E (APOE), in contrast to mouse models of Alzheimer's disease, in which microglia with the WAM gene signature are generated prematurely and in an APOE-dependent pathway similar to DAMs. Within the white matter, microglia frequently cluster in nodules, where they are engaged in clearing degenerated myelin. Thus, WAMs may represent a potentially protective response required to clear degenerated myelin accumulating during white matter aging and disease.


Assuntos
Microglia/fisiologia , Substância Branca/citologia , Substância Branca/crescimento & desenvolvimento , Envelhecimento/fisiologia , Doença de Alzheimer/genética , Animais , Apolipoproteínas E/genética , Doenças Desmielinizantes/patologia , Regulação da Expressão Gênica , Substância Cinzenta/citologia , Substância Cinzenta/crescimento & desenvolvimento , Imuno-Histoquímica , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/ultraestrutura , Bainha de Mielina/metabolismo , Receptores Imunológicos/biossíntese , Receptores Imunológicos/genética , Análise de Sequência de RNA , Transdução de Sinais/fisiologia , Análise de Célula Única
16.
Nat Commun ; 12(1): 1158, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627648

RESUMO

Niemann-Pick type C disease is a rare neurodegenerative disorder mainly caused by mutations in NPC1, resulting in abnormal late endosomal/lysosomal lipid storage. Although microgliosis is a prominent pathological feature, direct consequences of NPC1 loss on microglial function remain not fully characterized. We discovered pathological proteomic signatures and phenotypes in NPC1-deficient murine models and demonstrate a cell autonomous function of NPC1 in microglia. Loss of NPC1 triggers enhanced phagocytic uptake and impaired myelin turnover in microglia that precede neuronal death. Npc1-/- microglia feature a striking accumulation of multivesicular bodies and impaired trafficking of lipids to lysosomes while lysosomal degradation function remains preserved. Molecular and functional defects were also detected in blood-derived macrophages of NPC patients that provide a potential tool for monitoring disease. Our study underscores an essential cell autonomous role for NPC1 in immune cells and implies microglial therapeutic potential.


Assuntos
Colesterol/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Microglia/metabolismo , Doença de Niemann-Pick Tipo C/metabolismo , Animais , Western Blotting , Células Cultivadas , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Bainha de Mielina/metabolismo , Proteína C1 de Niemann-Pick , Doença de Niemann-Pick Tipo C/genética , Fagocitose/genética , Fagocitose/fisiologia , Proteômica/métodos
17.
Nat Neurosci ; 24(1): 47-60, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33349711

RESUMO

The repair of inflamed, demyelinated lesions as in multiple sclerosis (MS) necessitates the clearance of cholesterol-rich myelin debris by microglia/macrophages and the switch from a pro-inflammatory to an anti-inflammatory lesion environment. Subsequently, oligodendrocytes increase cholesterol levels as a prerequisite for synthesizing new myelin membranes. We hypothesized that lesion resolution is regulated by the fate of cholesterol from damaged myelin and oligodendroglial sterol synthesis. By integrating gene expression profiling, genetics and comprehensive phenotyping, we found that, paradoxically, sterol synthesis in myelin-phagocytosing microglia/macrophages determines the repair of acutely demyelinated lesions. Rather than producing cholesterol, microglia/macrophages synthesized desmosterol, the immediate cholesterol precursor. Desmosterol activated liver X receptor (LXR) signaling to resolve inflammation, creating a permissive environment for oligodendrocyte differentiation. Moreover, LXR target gene products facilitated the efflux of lipid and cholesterol from lipid-laden microglia/macrophages to support remyelination by oligodendrocytes. Consequently, pharmacological stimulation of sterol synthesis boosted the repair of demyelinated lesions, suggesting novel therapeutic strategies for myelin repair in MS.


Assuntos
Doenças Desmielinizantes/patologia , Microglia/fisiologia , Esteróis/biossíntese , Animais , Colesterol/metabolismo , Desmosterol/metabolismo , Encefalomielite Autoimune Experimental , Feminino , Perfilação da Expressão Gênica , Humanos , Inflamação/metabolismo , Inflamação/patologia , Metabolismo dos Lipídeos , Receptores X do Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Esclerose Múltipla , Oligodendroglia/metabolismo , Fagocitose , Esqualeno/metabolismo
18.
J Exp Med ; 217(5)2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32078678

RESUMO

Remyelination requires innate immune system function, but how exactly microglia and macrophages clear myelin debris after injury and tailor a specific regenerative response is unclear. Here, we asked whether pro-inflammatory microglial/macrophage activation is required for this process. We established a novel toxin-based spinal cord model of de- and remyelination in zebrafish and showed that pro-inflammatory NF-κB-dependent activation in phagocytes occurs rapidly after myelin injury. We found that the pro-inflammatory response depends on myeloid differentiation primary response 88 (MyD88). MyD88-deficient mice and zebrafish were not only impaired in the degradation of myelin debris, but also in initiating the generation of new oligodendrocytes for myelin repair. We identified reduced generation of TNF-α in lesions of MyD88-deficient animals, a pro-inflammatory molecule that was able to induce the generation of new premyelinating oligodendrocytes. Our study shows that pro-inflammatory phagocytic signaling is required for myelin debris degradation, for inflammation resolution, and for initiating the generation of new oligodendrocytes.


Assuntos
Doenças Desmielinizantes/patologia , Inflamação/patologia , Bainha de Mielina/metabolismo , Oligodendroglia/patologia , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Células Cultivadas , Modelos Animais de Doenças , Larva/efeitos dos fármacos , Lisofosfatidilcolinas/metabolismo , Camundongos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Mutação/genética , Bainha de Mielina/efeitos dos fármacos , Bainha de Mielina/patologia , Fator 88 de Diferenciação Mieloide/metabolismo , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/metabolismo , Fagócitos/efeitos dos fármacos , Fagócitos/patologia , Fagossomos/efeitos dos fármacos , Fagossomos/metabolismo , Proteoma/metabolismo , Remielinização/efeitos dos fármacos , Medula Espinal/patologia , Fator de Necrose Tumoral alfa/farmacologia , Peixe-Zebra
19.
EMBO Mol Med ; 12(4): e11227, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32154671

RESUMO

Triggering receptor expressed on myeloid cells 2 (TREM2) is essential for the transition of homeostatic microglia to a disease-associated microglial state. To enhance TREM2 activity, we sought to selectively increase the full-length protein on the cell surface via reducing its proteolytic shedding by A Disintegrin And Metalloproteinase (i.e., α-secretase) 10/17. We screened a panel of monoclonal antibodies against TREM2, with the aim to selectively compete for α-secretase-mediated shedding. Monoclonal antibody 4D9, which has a stalk region epitope close to the cleavage site, demonstrated dual mechanisms of action by stabilizing TREM2 on the cell surface and reducing its shedding, and concomitantly activating phospho-SYK signaling. 4D9 stimulated survival of macrophages and increased microglial uptake of myelin debris and amyloid ß-peptide in vitro. In vivo target engagement was demonstrated in cerebrospinal fluid, where nearly all soluble TREM2 was 4D9-bound. Moreover, in a mouse model for Alzheimer's disease-related pathology, 4D9 reduced amyloidogenesis, enhanced microglial TREM2 expression, and reduced a homeostatic marker, suggesting a protective function by driving microglia toward a disease-associated state.


Assuntos
Anticorpos Monoclonais/farmacologia , Glicoproteínas de Membrana/imunologia , Microglia , Mieloma Múltiplo , Receptores Imunológicos/imunologia , Peptídeos beta-Amiloides , Animais , Linhagem Celular Tumoral , Feminino , Macrófagos , Camundongos , Microglia/patologia , Ratos , Ratos Wistar
20.
Science ; 370(6518): 856-860, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33082293

RESUMO

The causative agent of coronavirus disease 2019 (COVID-19) is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For many viruses, tissue tropism is determined by the availability of virus receptors and entry cofactors on the surface of host cells. In this study, we found that neuropilin-1 (NRP1), known to bind furin-cleaved substrates, significantly potentiates SARS-CoV-2 infectivity, an effect blocked by a monoclonal blocking antibody against NRP1. A SARS-CoV-2 mutant with an altered furin cleavage site did not depend on NRP1 for infectivity. Pathological analysis of olfactory epithelium obtained from human COVID-19 autopsies revealed that SARS-CoV-2 infected NRP1-positive cells facing the nasal cavity. Our data provide insight into SARS-CoV-2 cell infectivity and define a potential target for antiviral intervention.


Assuntos
Betacoronavirus/fisiologia , Infecções por Coronavirus/virologia , Neuropilina-1/metabolismo , Pneumonia Viral/virologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do Vírus , Enzima de Conversão de Angiotensina 2 , Animais , Anticorpos Monoclonais/imunologia , Betacoronavirus/genética , COVID-19 , Células CACO-2 , Feminino , Células HEK293 , Interações entre Hospedeiro e Microrganismos , Humanos , Pulmão/metabolismo , Masculino , Nanopartículas Metálicas , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Neuropilina-1/química , Neuropilina-1/genética , Neuropilina-1/imunologia , Neuropilina-2/metabolismo , Mucosa Olfatória/metabolismo , Mucosa Olfatória/virologia , Pandemias , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/genética , Peptidil Dipeptidase A/metabolismo , Ligação Proteica , Domínios Proteicos , Mucosa Respiratória/metabolismo , SARS-CoV-2 , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Glicoproteína da Espícula de Coronavírus/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA