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1.
Nature ; 582(7810): 89-94, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32483373

RESUMO

A hexanucleotide-repeat expansion in C9ORF72 is the most common genetic variant that contributes to amyotrophic lateral sclerosis and frontotemporal dementia1,2. The C9ORF72 mutation acts through gain- and loss-of-function mechanisms to induce pathways that are implicated in neural degeneration3-9. The expansion is transcribed into a long repetitive RNA, which negatively sequesters RNA-binding proteins5 before its non-canonical translation into neural-toxic dipeptide proteins3,4. The failure of RNA polymerase to read through the mutation also reduces the abundance of the endogenous C9ORF72 gene product, which functions in endolysosomal pathways and suppresses systemic and neural inflammation6-9. Notably, the effects of the repeat expansion act with incomplete penetrance in families with a high prevalence of amyotrophic lateral sclerosis or frontotemporal dementia, indicating that either genetic or environmental factors modify the risk of disease for each individual. Identifying disease modifiers is of considerable translational interest, as it could suggest strategies to diminish the risk of developing amyotrophic lateral sclerosis or frontotemporal dementia, or to slow progression. Here we report that an environment with reduced abundance of immune-stimulating bacteria10,11 protects C9orf72-mutant mice from premature mortality and significantly ameliorates their underlying systemic inflammation and autoimmunity. Consistent with C9orf72 functioning to prevent microbiota from inducing a pathological inflammatory response, we found that reducing the microbial burden in mutant mice with broad spectrum antibiotics-as well as transplanting gut microflora from a protective environment-attenuated inflammatory phenotypes, even after their onset. Our studies provide further evidence that the microbial composition of our gut has an important role in brain health and can interact in surprising ways with well-known genetic risk factors for disorders of the nervous system.


Assuntos
Proteína C9orf72/genética , Microbioma Gastrointestinal/fisiologia , Gliose/microbiologia , Gliose/patologia , Inflamação/genética , Inflamação/microbiologia , Medula Espinal/patologia , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Animais , Antibacterianos/farmacologia , Autoimunidade/efeitos dos fármacos , Autoimunidade/genética , Autoimunidade/imunologia , Movimento Celular/efeitos dos fármacos , Citocinas/imunologia , Transplante de Microbiota Fecal , Feminino , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/imunologia , Gliose/genética , Gliose/prevenção & controle , Inflamação/patologia , Inflamação/prevenção & controle , Mutação com Perda de Função/genética , Masculino , Camundongos , Microglia/imunologia , Microglia/microbiologia , Microglia/patologia , Medula Espinal/imunologia , Medula Espinal/microbiologia , Taxa de Sobrevida
2.
PLoS One ; 15(3): e0226584, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32191733

RESUMO

The pathogenesis of spinal cord injury (SCI) remains poorly understood and treatment remains limited. Emerging evidence indicates that post-SCI inflammation is severe but the role of reactive astrogliosis not well understood given its implication in ongoing inflammation as damaging or neuroprotective. We have completed an extensive systematic study with MRI, histopathology, proteomics and ELISA analyses designed to further define the severe protracted and damaging inflammation after SCI in a rat model. We have identified 3 distinct phases of SCI: acute (first 2 days), inflammatory (starting day 3) and resolution (>3 months) in 16 weeks follow up. Actively phagocytizing, CD68+/CD163- macrophages infiltrate myelin-rich necrotic areas converting them into cavities of injury (COI) when deep in the spinal cord. Alternatively, superficial SCI areas are infiltrated by granulomatous tissue, or arachnoiditis where glial cells are obliterated. In the COI, CD68+/CD163- macrophage numbers reach a maximum in the first 4 weeks and then decline. Myelin phagocytosis is present at 16 weeks indicating ongoing inflammatory damage. The COI and arachnoiditis are defined by a wall of progressively hypertrophied astrocytes. MR imaging indicates persistent spinal cord edema that is linked to the severity of inflammation. Microhemorrhages in the spinal cord around the lesion are eliminated, presumably by reactive astrocytes within the first week post-injury. Acutely increased levels of TNF-alpha, IL-1beta, IFN-gamma and other pro-inflammatory cytokines, chemokines and proteases decrease and anti-inflammatory cytokines increase in later phases. In this study we elucidated a number of fundamental mechanisms in pathogenesis of SCI and have demonstrated a close association between progressive astrogliosis and reduction in the severity of inflammation.


Assuntos
Aracnoidite/imunologia , Gliose/imunologia , Traumatismos da Medula Espinal/complicações , Medula Espinal/patologia , Animais , Anti-Inflamatórios , Aracnoidite/diagnóstico , Aracnoidite/patologia , Astrócitos/imunologia , Astrócitos/metabolismo , Citocinas/imunologia , Citocinas/metabolismo , Modelos Animais de Doenças , Gliose/diagnóstico , Gliose/patologia , Humanos , Macrófagos/imunologia , Macrófagos/metabolismo , Imagem por Ressonância Magnética , Masculino , Bainha de Mielina/imunologia , Bainha de Mielina/patologia , Ratos , Índice de Gravidade de Doença , Medula Espinal/citologia , Medula Espinal/diagnóstico por imagem , Medula Espinal/imunologia , Traumatismos da Medula Espinal/diagnóstico por imagem , Traumatismos da Medula Espinal/imunologia , Traumatismos da Medula Espinal/patologia , Fatores de Tempo
3.
Immunity ; 52(1): 167-182.e7, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31883839

RESUMO

Multiple sclerosis (MS) is a demyelinating, autoimmune disease of the central nervous system. While work has focused on myelin and axon loss in MS, less is known about mechanisms underlying synaptic changes. Using postmortem human MS tissue, a preclinical nonhuman primate model of MS, and two rodent models of demyelinating disease, we investigated synapse changes in the visual system. Similar to other neurodegenerative diseases, microglial synaptic engulfment and profound synapse loss were observed. In mice, synapse loss occurred independently of local demyelination and neuronal degeneration but coincided with gliosis and increased complement component C3, but not C1q, at synapses. Viral overexpression of the complement inhibitor Crry at C3-bound synapses decreased microglial engulfment of synapses and protected visual function. These results indicate that microglia eliminate synapses through the alternative complement cascade in demyelinating disease and identify a strategy to prevent synapse loss that may be broadly applicable to other neurodegenerative diseases. VIDEO ABSTRACT.


Assuntos
Complemento C3/imunologia , Encefalomielite Autoimune Experimental/patologia , Microglia/patologia , Esclerose Múltipla/patologia , Sinapses/patologia , Tálamo/patologia , Idoso , Idoso de 80 Anos ou mais , Animais , Callithrix , Linhagem Celular Tumoral , Complemento C3/antagonistas & inibidores , Modelos Animais de Doenças , Feminino , Gliose/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptores de Complemento 3b/metabolismo
4.
J Neuroinflammation ; 16(1): 235, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31771656

RESUMO

BACKGROUND: Vacuolar sorting protein 35 (VPS35), a critical component of retromer, is essential for selective endosome-to-Golgi retrieval of membrane proteins. It is highly expressed in microglial cells, in addition to neurons. We have previously demonstrated microglial VPS35's functions in preventing hippocampal, but not cortical, microglial activation, and in promoting adult hippocampal neurogenesis. However, microglial VPS35's role in the cortex in response to ischemic stroke remains largely unclear. METHODS: We used mice with VPS35 cKO (conditional knockout) in microglial cells and examined and compared their responses to ischemic stroke with control mice. The brain damage, cell death, changes in glial cells and gene expression, and sensorimotor deficits were assessed by a combination of immunohistochemical and immunofluorescence staining, RT-PCR, Western blot, and neurological functional behavior tests. RESULTS: We found that microglial VPS35 loss results in an increase of anti-inflammatory microglia in mouse cortex after ischemic stroke. The ischemic stroke-induced brain injury phenotypes, including brain damage, neuronal death, and sensorimotor deficits, were all attenuated by microglial VPS35-deficiency. Further analysis of protein expression changes revealed a reduction in CX3CR1 (CX3C chemokine receptor 1) in microglial VPS35-deficient cortex after ischemic stroke, implicating CX3CR1 as a potential cargo of VPS35 in this event. CONCLUSION: Together, these results reveal an unrecognized function of microglial VPS35 in enhancing ischemic brain injury-induced inflammatory microglia, but suppressing the injury-induced anti-inflammatory microglia. Consequently, microglial VPS35 cKO mice exhibit attenuation of ischemic brain injury response.


Assuntos
Isquemia Encefálica/metabolismo , Polaridade Celular/fisiologia , Microglia/metabolismo , Córtex Sensório-Motor/metabolismo , Acidente Vascular Cerebral/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Isquemia Encefálica/genética , Isquemia Encefálica/patologia , Receptor 1 de Quimiocina CX3C/genética , Receptor 1 de Quimiocina CX3C/metabolismo , Morte Celular/fisiologia , Modelos Animais de Doenças , Gliose/genética , Gliose/metabolismo , Gliose/patologia , Camundongos , Camundongos Knockout , Destreza Motora/fisiologia , Córtex Sensório-Motor/patologia , Acidente Vascular Cerebral/genética , Acidente Vascular Cerebral/patologia , Proteínas de Transporte Vesicular/genética
5.
J Neuroinflammation ; 16(1): 187, 2019 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-31606043

RESUMO

BACKGROUND: The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor activated by environmental agonists and dietary tryptophan metabolites for the immune response and cell cycle regulation. Emerging evidence suggests that AHR activation after acute stroke may play a role in brain ischemic injury. However, whether AHR activation alters poststroke astrogliosis and neurogenesis remains unknown. METHODS: We adopted conditional knockout of AHR from nestin-expressing neural stem/progenitor cells (AHRcKO) and wild-type (WT) mice in the permanent middle cerebral artery occlusion (MCAO) model. WT mice were treated with either vehicle or the AHR antagonist 6,2',4'-trimethoxyflavone (TMF, 5 mg/kg/day) intraperitoneally. The animals were examined at 2 and 7 days after MCAO. RESULTS: The AHR signaling pathway was significantly upregulated after stroke. Both TMF-treated WT and AHRcKO mice showed significantly decreased infarct volume, improved sensorimotor, and nonspatial working memory functions compared with their respective controls. AHR immunoreactivities were increased predominantly in activated microglia and astrocytes after MCAO compared with the normal WT controls. The TMF-treated WT and AHRcKO mice demonstrated significant amelioration of astrogliosis and microgliosis. Interestingly, these mice also showed augmentation of neural progenitor cell proliferation at the ipsilesional neurogenic subventricular zone (SVZ) and the hippocampal subgranular zone. At the peri-infarct cortex, the ipsilesional SVZ/striatum, and the hippocampus, both the TMF-treated and AHRcKO mice demonstrated downregulated IL-1ß, IL-6, IFN-γ, CXCL1, and S100ß, and concomitantly upregulated Neurogenin 2 and Neurogenin 1. CONCLUSION: Neural cell-specific AHR activation following acute ischemic stroke increased astrogliosis and suppressed neurogenesis in adult mice. AHR inhibition in acute stroke may potentially benefit functional outcomes likely through reducing proinflammatory gliosis and preserving neurogenesis.


Assuntos
Encéfalo/metabolismo , Gliose/metabolismo , Neurogênese/fisiologia , Neurônios/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Acidente Vascular Cerebral/metabolismo , Fatores Etários , Animais , Encéfalo/patologia , Gliose/patologia , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Acidente Vascular Cerebral/patologia
6.
Cancer Cell ; 36(3): 250-267.e9, 2019 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-31526758

RESUMO

How lymphoma cells (LCs) invade the brain during the development of central nervous system lymphoma (CNSL) is unclear. We found that NF-κB-induced gliosis promotes CNSL in immunocompetent mice. Gliosis elevated cell-adhesion molecules, which increased LCs in the brain but was insufficient to induce CNSL. Astrocyte-derived CCL19 was required for gliosis-induced CNSL. Deleting CCL19 in mice or CCR7 from LCs abrogated CNSL development. Two-photon microscopy revealed LCs transiently entering normal brain parenchyma. Astrocytic CCL19 enhanced parenchymal CNS retention of LCs, thereby promoting CNSL formation. Aged, gliotic wild-type mice were more susceptible to forming CNSL than young wild-type mice, and astrocytic CCL19 was observed in both human gliosis and CNSL. Therefore, CCL19-CCR7 interactions may underlie an increased age-related risk for CNSL.


Assuntos
Envelhecimento/patologia , Neoplasias do Sistema Nervoso Central/patologia , Quimiocina CCL19/metabolismo , Gliose/patologia , Linfoma/patologia , Adolescente , Adulto , Idoso , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Barreira Hematoencefálica/citologia , Barreira Hematoencefálica/diagnóstico por imagem , Barreira Hematoencefálica/patologia , Linhagem Celular Tumoral/transplante , Neoplasias do Sistema Nervoso Central/diagnóstico por imagem , Neoplasias do Sistema Nervoso Central/cirurgia , Quimiocina CCL19/genética , Quimiocina CXCL12 , Modelos Animais de Doenças , Feminino , Gliose/diagnóstico por imagem , Humanos , Microscopia Intravital , Linfoma/diagnóstico por imagem , Linfoma/cirurgia , Masculino , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência por Excitação Multifotônica , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Receptores CCR7/genética , Receptores CCR7/metabolismo , Imagem com Lapso de Tempo , Adulto Jovem
7.
Acta Diabetol ; 56(12): 1333-1339, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31506721

RESUMO

AIMS: This study aimed to evaluate the effect of pioglitazone on brown adipose tissue function and hypothalamic gliosis in humans. Brown adipose tissue and the hypothalamus are regarded as important potential pharmacological targets to metabolic diseases, and defining the impact of current therapies on their structure and/or function could provide therapeutic advance in this field. METHODS: Six patients with type 2 diabetes were treated for 24 weeks with pioglitazone 30 mg/day as an add-on therapy. Brown adipose tissue glucose uptake and volume were determined using 18F-FDG PET/CT scans; hypothalamic gliosis was determined using MRI scans; blood was collected for hormone and biochemistry measurements. All tests were performed at inclusion and six months after pioglitazone introduction. RESULTS: Pioglitazone treatment led to a significant 3% body mass increase. There were neither changes in cold-induced brown adipose tissue glucose uptake and volume nor changes in hypothalamic gliosis. CONCLUSIONS: This is a proof-of-concept study that provides clinical evidence for a lack of action of a thiazolidinedione, pioglitazone, to promote homogeneous and measurable changes in brown adipose tissue volume and also in hypothalamic gliosis after 6 months of treatment.


Assuntos
Tecido Adiposo Marrom/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Gliose/prevenção & controle , Hipotálamo/efeitos dos fármacos , Hipotálamo/patologia , Pioglitazona/farmacologia , Tecido Adiposo Marrom/diagnóstico por imagem , Tecido Adiposo Marrom/patologia , Adulto , Idoso , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/patologia , Quimioterapia Combinada , Feminino , Fluordesoxiglucose F18 , Gliose/diagnóstico , Gliose/patologia , Humanos , Hipotálamo/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/diagnóstico , Obesidade/tratamento farmacológico , Obesidade/patologia , Tamanho do Órgão/efeitos dos fármacos , Sobrepeso/complicações , Sobrepeso/diagnóstico , Sobrepeso/tratamento farmacológico , Sobrepeso/patologia , Pioglitazona/administração & dosagem , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Estudo de Prova de Conceito , Tiazolidinedionas/administração & dosagem , Tiazolidinedionas/farmacologia
8.
Glia ; 67(12): 2221-2247, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31429127

RESUMO

Astrocytes are key cellular partners for neurons in the central nervous system. Astrocytes react to virtually all types of pathological alterations in brain homeostasis by significant morphological and molecular changes. This response was classically viewed as stereotypical and is called astrogliosis or astrocyte reactivity. It was long considered as a nonspecific, secondary reaction to pathological conditions, offering no clues on disease-causing mechanisms and with little therapeutic value. However, many studies over the last 30 years have underlined the crucial and active roles played by astrocytes in physiology, ranging from metabolic support, synapse maturation, and pruning to fine regulation of synaptic transmission. This prompted researchers to explore how these new astrocyte functions were changed in disease, and they reported alterations in many of them (sometimes beneficial, mostly deleterious). More recently, cell-specific transcriptomics revealed that astrocytes undergo massive changes in gene expression when they become reactive. This observation further stressed that reactive astrocytes may be very different from normal, nonreactive astrocytes and could influence disease outcomes. To make the picture even more complex, both normal and reactive astrocytes were shown to be molecularly and functionally heterogeneous. Very little is known about the specific roles that each subtype of reactive astrocytes may play in different disease contexts. In this review, we have interrogated researchers in the field to identify and discuss points of consensus and controversies about reactive astrocytes, starting with their very name. We then present the emerging knowledge on these cells and future challenges in this field.


Assuntos
Astrócitos/metabolismo , Encéfalo/metabolismo , Doenças do Sistema Nervoso Central/metabolismo , Animais , Astrócitos/patologia , Encéfalo/patologia , Doenças do Sistema Nervoso Central/patologia , Gliose/metabolismo , Gliose/patologia , Humanos
9.
Cir Cir ; 87(5): 554-558, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31448801

RESUMO

Background: Stereotactic biopsy has been reported as a useful and safety procedure in pediatric patients. In adult patients exist more controversy because a greater number of diagnostic options. Objective: To demonstrate its usefulness and safety in adult patients with posterior fossa pathology. Method: From 2006-2014, 23 patients were operated from posterior fossa. Variables: age, gender, state, pre- and postoperative diagnosis, stereotactic device, location and complications. Results: 52.2% females and 47.8% males. The location was ponto-mesencephalic 43.5%, cerebellum 39.1%, bulbar 13% and pineal region 4.3%. The preoperative diagnosis was brainstem glioma 78.2%, lymphoma 8.7%, and meningioma, metastasis and abscess 4.3% each one. In 73.9% Zamorano-Dujovni device was used and in 26.1% the CRW. The definitive diagnosis was pilocytic astrocytoma 17.4%, diffuse astrocytoma 13%, inflammatory response 13%, anaplastic astrocytoma 8.7%, gliosis 8.7%, glioblastoma, neuroectodermic primitive tumor, germinoma, pineocytoma and cryptococcosis 4.3% each one. In 17.4% there was no diagnosis. The preoperative diagnosis was concordant in 43.5%. One transient deficit and one pin displacement 4.3% were present. 91.4% without complications. Conclusions: It is a useful, necessary and safety procedure in adult patients.


Assuntos
Biópsia , Neoplasias Infratentoriais/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia/efeitos adversos , Biópsia/métodos , Encefalopatias/patologia , Feminino , Glioma/diagnóstico , Glioma/patologia , Gliose/diagnóstico , Gliose/patologia , Humanos , Neoplasias Infratentoriais/diagnóstico , Hemorragias Intracranianas/diagnóstico , Hemorragias Intracranianas/patologia , Masculino , Meningite Criptocócica/patologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Técnicas Estereotáxicas/efeitos adversos , Neoplasias Supratentoriais/diagnóstico , Neoplasias Supratentoriais/patologia , Adulto Jovem
10.
J Neuroinflammation ; 16(1): 163, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31383034

RESUMO

BACKGROUND: Traumatic brain injury (TBI) is a major cause of death and disability. T cells were shown to infiltrate the brain during the first days after injury and to exacerbate tissue damage. The objective of this study was to investigate the hitherto unresolved role of immunosuppressive, regulatory T cells (Tregs) in experimental TBI. METHODS: "Depletion of regulatory T cell" (DEREG) and wild type (WT) C57Bl/6 mice, treated with diphtheria toxin (DTx) to deplete Tregs or to serve as control, were subjected to the controlled cortical impact (CCI) model of TBI. Neurological and motor deficits were examined until 5 days post-injury (dpi). At the 5 dpi endpoint, (immuno-) histological, protein, and gene expression analyses were carried out to evaluate the consequences of Tregs depletion. Comparison of parametric or non-parametric data between two groups was done using Student's t test or the Mann-Whitney U test. For multiple comparisons, p values were calculated by one-way or two-way ANOVA followed by specific post hoc tests. RESULTS: The overall neurological outcome at 5 dpi was not different between DEREG and WT mice but more severe motor deficits occurred transiently at 1 dpi in DEREG mice. DEREG and WT mice did not differ in the extent of brain damage, blood-brain barrier (BBB) disruption, or neuronal excitotoxicity, as examined by lesion volumetry, immunoglobulin G (IgG) extravasation, or calpain-generated αII-spectrin breakdown products (SBDPs), respectively. In contrast, increased protein levels of glial fibrillary acidic protein (GFAP) and GFAP+ astrocytes in the ipsilesional brain tissue indicated exaggerated reactive astrogliosis in DEREG mice. T cell counts following anti-CD3 immunohistochemistry and gene expression analyses of Cd247 (CD3 subunit zeta) and Cd8a (CD8a) further indicated an increased number of T cells infiltrating the brain injury sites of DEREG mice compared to WT. These changes coincided with increased gene expression of pro-inflammatory interferon-γ (Ifng) in DEREG mice compared to WT in the injured brain. CONCLUSIONS: The results show that the depletion of Tregs attenuates T cell brain infiltration, reactive astrogliosis, interferon-γ gene expression, and transiently motor deficits in murine acute traumatic brain injury.


Assuntos
Astrócitos/patologia , Lesões Encefálicas Traumáticas/patologia , Encéfalo/patologia , Gliose/patologia , Interferon gama/genética , Depleção Linfocítica , Linfócitos T Reguladores/patologia , Animais , Astrócitos/imunologia , Encéfalo/imunologia , Lesões Encefálicas Traumáticas/genética , Lesões Encefálicas Traumáticas/imunologia , Modelos Animais de Doenças , Gliose/genética , Gliose/imunologia , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Camundongos , Linfócitos T Reguladores/imunologia
11.
Ann Clin Transl Neurol ; 6(7): 1178-1190, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31353853

RESUMO

OBJECTIVE: Diffusion tensor imaging (DTI) of the white matter is a biomarker for neurological disease burden in tuberous sclerosis complex (TSC). To clarify the basis of abnormal diffusion in TSC, we correlated ex vivo high-resolution diffusion imaging with histopathology in four tissue types: cortex, tuber, perituber, and white matter. METHODS: Surgical specimens of three children with TSC were scanned in a 3T or 7T MRI with a structural image isotropic resolution of 137-300 micron, and diffusion image isotropic resolution of 270-1,000 micron. We stained for myelin (luxol fast blue, LFB), gliosis (glial fibrillary acidic protein, GFAP), and neurons (NeuN) and registered the digitized histopathology slides (0.686 micron resolution) to MRI for visual comparison. We then performed colocalization analysis in four tissue types in each specimen. Finally, we applied a linear mixed model (LMM) for pooled analysis across the three specimens. RESULTS: In white matter and perituber regions, LFB optical density measures correlated with fractional anisotropy (FA) and inversely with mean diffusivity (MD). In white matter only, GFAP correlated with MD, and inversely with FA. In tubers and in the cortex, there was little variation in mean LFB and GFAP signal intensity, and no correlation with MRI metrics. Neuronal density correlated with MD. In the analysis of the combined specimens, the most robust correlation was between white matter MD and LFB metrics. INTERPRETATION: In TSC, diffusion imaging abnormalities in microscopic tissue types correspond to specific histopathological markers. Across all specimens, white matter diffusivity correlates with myelination.


Assuntos
Bainha de Mielina/patologia , Esclerose Tuberosa/diagnóstico por imagem , Esclerose Tuberosa/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Anisotropia , Encéfalo/patologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/patologia , Imagem de Tensor de Difusão/métodos , Feminino , Gliose/patologia , Humanos , Lactente , Recém-Nascido , Masculino , Neurônios/patologia
12.
Exp Neurol ; 320: 113003, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31260658

RESUMO

Germinal matrix hemorrhage (GMH) results from the rupture of the immature thin-walled blood vessels and consequent bleeding into the subependymal germinal matrix and possible lateral ventricles. The purpose of this study is to investigate how astrogliosis impacts the glymphatic-meningeal lymphatic system in cerebrospinal fluid (CSF) reabsorption after GMH and how the anti-scarring agent olomoucine attenuates post-hemorrhagic hydrocephalus. GMH was induced by stereotaxic collagenase infusion into P7 Sprague-Dawley rats of both sexes. Western blot and immunofluorescence were used to assess astrogliosis and how astrogliosis affects glymphatic function by measuring Aquaporin-4 expression. Intracisternal injection of fluorescence tracer was used to measure CSF diffusion throughout the brain, its dispersion in the paravascular area and CSF drainage into the deep cervical lymph nodes at 28 days after GMH. Both short-term and long-term behavioral tests were used to assess the neurological outcomes. Nissl staining was used to assess the morphological changes at 28 days after hemorrhage. GMH elicited astrogliotic scarring and reduced the exchange between CSF and interstitial fluid, as well as CSF reabsorption through the meningeal lymphatic vessels. This might be associated with redistribution of Aquaporin-4. Olomoucine ameliorated scar tissue formation and attenuated post-hemorrhagic hydrocephalus. These findings of this study suggested that the glymphatic system might play a role in CSF reabsorption in neonates following GMH. Scar tissue formation impairs this CSF clearance route, and therefore astrogliosis inhibition might be a potential therapeutic strategy for neonatal post-hemorrhagic hydrocephalus.


Assuntos
Hemorragia Cerebral/líquido cefalorraquidiano , Gliose/patologia , Sistema Glinfático/fisiologia , Hidrocefalia/líquido cefalorraquidiano , Animais , Animais Recém-Nascidos , Aquaporina 4/metabolismo , Hemorragia Cerebral/complicações , Hemorragia Cerebral/patologia , Líquido Cefalorraquidiano/metabolismo , Feminino , Hidrocefalia/etiologia , Hidrocefalia/patologia , Masculino , Ratos , Ratos Sprague-Dawley
14.
Proc Natl Acad Sci U S A ; 116(33): 16603-16612, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31350349

RESUMO

Microglia respond to damage and microenvironmental changes within the central nervous system by morphologically transforming and migrating to the lesion, but the real-time behavior of populations of these resident immune cells and the neurons they support have seldom been observed simultaneously. Here, we have used in vivo high-resolution optical coherence tomography (OCT) and scanning laser ophthalmoscopy with and without adaptive optics to quantify the 3D distribution and dynamics of microglia in the living retina before and after local damage to photoreceptors. Following photoreceptor injury, microglia migrated both laterally and vertically through the retina over many hours, forming a tight cluster within the area of visible damage that resolved over 2 wk. In vivo OCT optophysiological assessment revealed that the photoreceptors occupying the damaged region lost all light-driven signaling during the period of microglia recruitment. Remarkably, photoreceptors recovered function to near-baseline levels after the microglia had departed the injury locus. These results demonstrate the spatiotemporal dynamics of microglia engagement and restoration of neuronal function during tissue remodeling and highlight the need for mechanistic studies that consider the temporal and structural dynamics of neuron-microglia interactions in vivo.


Assuntos
Diagnóstico por Imagem , Microglia/patologia , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patologia , Retina/diagnóstico por imagem , Retina/lesões , Transdução de Sinais , Animais , Movimento Celular/efeitos da radiação , Gliose/patologia , Luz , Camundongos Endogâmicos C57BL , Microglia/efeitos da radiação , Células Fotorreceptoras de Vertebrados/efeitos da radiação , Recuperação de Função Fisiológica , Retina/fisiopatologia , Retina/efeitos da radiação , Fatores de Tempo , Tomografia de Coerência Óptica
15.
Neurochem Int ; 129: 104502, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299418

RESUMO

Heterozygous mutations in GBA1, the gene which encodes the lysosomal enzyme glucocerebrosidase (GCase), are a strong genetic risk factor for the development of Lewy body dementia (LBD). Until this point however, recapitulation of the symptoms and pathology of LBD has been limited to a homozygous GBA1 mouse model which genetically and enzymatically reflects the lysosomal storage disorder Gaucher's disease. This study reports for the first time cognitive impairment by two independent behavioural tests in heterozygous GBA1 mutant mice (D409V/WT) which demonstrate significant cognitive impairment by the age of 12 months. Furthermore, reductions in GBA1 GCase enzyme activity within the brain reflects levels seen in sporadic and GBA1 mutant LBD patients. While there is no overt deposition of Lewy bodies within the hippocampus, alterations to cholinergic machinery and glial proliferation are evident, both pathological features of LBD. Interestingly, we also describe the novel finding of significantly reduced GBA2 GCase enzyme activity specifically within the hippocampus. This suggests that reduced GBA1 GCase enzyme activity dis-equilibrates the finely balanced glycosphingolipid metabolism pathway and that reductions in GBA2 GCase enzyme could contribute to the pathological and behavioural effects seen. Overall, this study presents evidence to suggest that pathological hallmarks associated with LBD specifically affecting brain regions intrinsically linked with cognition are present in the D409V/WT mice. In the absence of Lewy body deposition, the D409V/WT mice could be considered an early pre-clinical model of LBD with potential for drug discovery. Since few robust pre-clinical models of LBD currently exist, with further characterization, the mouse model described here may contribute significantly to developments in the LBD field.


Assuntos
Transtornos Cognitivos/genética , Modelos Animais de Doenças , Glucosilceramidase/genética , Hipocampo/enzimologia , Doença por Corpos de Lewy/enzimologia , Animais , Córtex Cerebral/enzimologia , Comportamento Exploratório , Gliose/genética , Gliose/patologia , Glucosilceramidase/deficiência , Glucosilceramidas/metabolismo , Glicoesfingolipídeos/metabolismo , Heterozigoto , Hipocampo/patologia , Lisossomos/enzimologia , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Mutação de Sentido Incorreto , Teste de Desempenho do Rota-Rod , Proteínas Vesiculares de Transporte de Acetilcolina/análise , beta-Glucosidase/deficiência
16.
J Neuroinflammation ; 16(1): 135, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31272467

RESUMO

BACKGROUND: Conditional ablation of the Smarca5 gene in mice severely impairs the postnatal growth of the cerebellum and causes an ataxic phenotype. Comparative gene expression studies indicated that complement-related proteins were upregulated in the cerebellum of Smarca5 mutant mice. Complement proteins play critical roles within innate immune signaling pathways and, in the brain, are produced by glial cells under both normal and pathological conditions. The C3 complement protein-derived signaling peptide, C3a, has been implicated in contributing to both tissue damage and repair in conditions such as multiple sclerosis and stroke. Here, we investigated whether C3a receptor (C3aR) signaling promoted damage or repair in the developing cerebellum of Smarca5 mutant mice. METHODS: Brain and cerebellum lysates from single Smarca5 conditional knockout (Smarca5 cKO) mice, C3aR1 KO mice, or double mutant mice were used for qRT-PCR and immunoblotting to assess the contribution of C3aR to the Smarca5 cKO brain pathology. Immunohistochemistry was used to characterize alterations to astroglia and phagocyte cells in the developing cerebellum of each of the genotypes. RESULTS: C3aR signaling was observed to limit gliosis and promote granule neuron survival during postnatal cerebellar development. In Smarca5 cKO mice, disorganized astroglia with increased GFAP expression develops concurrently with cerebellar granule neuron loss and phagocyte invasion over the first 10 days following birth. Potential ligand precursors of C3aR-VGF and C3-were found to have upregulated expression and/or altered processing during this time. Phagocytes (microglia and macrophages) in both the control and Smarca5 mutant mice were the only cells observed to express C3aR. Loss of C3aR in the Smarca5 cKO cerebellum resulted in increased numbers of apoptotic cells and early phagocyte invasion into the external granule cell layer, as well as an exacerbated disorganization of the Bergmann glia. The loss of C3aR expression also attenuated an increase in the expression of the efferocytosis-related protein, MerTK, whose transcript was upregulated ~ 2.5-fold in the Smarca5 mutant cerebellum at P10. CONCLUSIONS: This data indicates that C3aR can play an important role in limiting astrogliosis and regulating phagocyte phenotypes following developmental cell loss in the brain.


Assuntos
Cerebelo/metabolismo , Gliose/metabolismo , Transtornos do Neurodesenvolvimento/metabolismo , Receptores Acoplados a Proteínas-G/deficiência , Transdução de Sinais/fisiologia , Adenosina Trifosfatases/deficiência , Adenosina Trifosfatases/genética , Sequência de Aminoácidos , Animais , Cerebelo/patologia , Proteínas Cromossômicas não Histona/deficiência , Proteínas Cromossômicas não Histona/genética , Gliose/genética , Gliose/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia , Receptores Acoplados a Proteínas-G/genética
18.
Neurotoxicology ; 74: 40-46, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31121239

RESUMO

Cigarette smoke exposure during pregnancy into infancy affects brain growth and development in both short and long term (into adulthood). Using a mouse model of pre- into post- natal cigarette smoke exposure (SE), we aimed to determine the effects on brain derived neurotrophic factor (BDNF) and its receptor TrkB, neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) and its receptor PAC1, and astrocyte (GFAP) and microglia (Iba-1) immunohistochemical expression, in seven nuclei of the medulla and the facial (FAC) nucleus of the pons. Male pups of dams exposed to two cigarettes (nicotine <1.2 mg, CO <15 mg) twice daily for six weeks prior to mating, during gestation and lactation (n = 5; SE), were compared to pups exposed to air under the same condition (n = 5; SHAM) at postnatal day 20. Expression changes were only evident for BDNF, TrkB and PAC1 and included decreased BDNF in the hypoglossal (XII) nucleus and nucleus of the solitary tract (NTS), increased TrkB in XII but decreased TrkB in the FAC, and increased PAC1 in 4 nuclei of the medulla including the NTS. These results suggest that the effect of SE on the brainstem are region and marker selective, affecting regions of respiratory control (XII and NTS), and restricted to the BDNF system and PAC1, with no effect on activation states of astrocytes or microglia.


Assuntos
Tronco Encefálico/efeitos dos fármacos , Tronco Encefálico/metabolismo , Fator Neurotrófico Derivado do Encéfalo/biossíntese , Gliose/induzido quimicamente , Gliose/patologia , Microglia/efeitos dos fármacos , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/biossíntese , Efeitos Tardios da Exposição Pré-Natal/patologia , Poluição por Fumaça de Tabaco/efeitos adversos , Animais , Tronco Encefálico/patologia , Feminino , Imuno-Histoquímica , Masculino , Bulbo/efeitos dos fármacos , Bulbo/metabolismo , Bulbo/patologia , Glicoproteínas de Membrana/biossíntese , Camundongos , Nicotina/toxicidade , Agonistas Nicotínicos/toxicidade , Gravidez , Proteínas Tirosina Quinases/biossíntese , Produtos do Tabaco
19.
Iran Biomed J ; 23(5): 324-9, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31103020

RESUMO

Background: A human immunodeficiency virus type 1 (HIV-1)-based lentiviral vector (LV) pseudotyped by a variant of rabies envelope glycoprotein, FUG-B2, has previously been prepared and used in transfection of hippocampal CA1 ("Cornu Ammonis" area 1) neurons. This study aimed to verify reactive gliosis and neuronal damage after injection of the vector into the rat hippocampus. Methods: HEK 293T cells were transfected with transfer (fck-Jaws-GFP-ER2), envelope (FUG-B2), and packaging (pMDLg/pRRE, pRSV-Rev) plasmids, and the vector was injected into CA1 of the rat hippocampus. After one week, transduction efficiency, and the number of neuronal and astroglial cells were determined in CA1 and CA3 by double staining of the brain slices. Results: Hippocampal cells were successfully transfected as 92.7% of CA1 and 95.8% of CA3 neuronal cells expressed GFP. The frequency of neuronal and astroglial cells in CA1 and CA3 of the vector-injected rats remained unchanged compared to those in the control and the saline-injected rats. Furthermore, no morphological change was found in hippocampal astrocytes and neuronal cells. Conclusion: The HIV-1-based LV pseudotyped by FUG-B2 is safe and does not cause neuroinflammation and neuronal loss once directly delivered into the rat hippocampus.


Assuntos
Vetores Genéticos/metabolismo , Gliose/patologia , Glicoproteínas/metabolismo , Hipocampo/patologia , Lentivirus/metabolismo , Degeneração Neural/patologia , Raiva/metabolismo , Animais , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Masculino , Ratos Wistar
20.
Mol Neurobiol ; 56(11): 7420-7432, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31041656

RESUMO

The amyloid ß (Aß) peptide, correlated with development of Alzheimer's disease (AD), is produced by sequential proteolytic cleavage of the amyloid precursor protein (APP) by ß- and γ-secretases. Alternative proteolytic cleavage of APP by α-secretase prevents formation of Aß peptide and produces a neuroprotective protein, a soluble fragment of APPα (sAPPα). We previously generated a single-chain variable domain antibody fragment (scFv) that binds APP at the ß-secretase cleavage site and blocks cleavage of APP (iBsec1), and a second scFv which has been engineered to have α-secretase-like activity that increases α-secretase cleavage of APP (Asec1a) and showed that a bispecific antibody (Diab) combining both iBsec1 and Asec1a constructs protects mammalian cells from oxidative stress. Here, we show that the diabody is an effective therapeutic agent in a mouse model of AD. An apolipoprotein B (ApoB) binding domain peptide was genetically added to the diabody to facilitate transfer across the blood-brain barrier, and a recombinant human adeno-associated virus 2/8 (rAAV2/8) was used as a vector to express the gene constructs in a APP/PS1 mouse model of AD. The diabody increased levels of sAPPα, decreased Aß deposits and levels of oligomeric Aß, increased neuronal health as indicated by MAP2 and synaptophysin staining, increased hippocampal neurogenesis, and most importantly dramatically increased survival rates compared with untreated mice or mice treated only with the ß-secretase inhibitor. These results indicate that altering APP processing to inhibit ß-site activity while simultaneously promoting α-secretase processing provides substantially increased neuronal benefits compared with inhibition of ß-secretase processing alone and represents a promising new therapeutic approach for treating AD.


Assuntos
Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Anticorpos Biespecíficos/farmacologia , Neurônios/metabolismo , Doença de Alzheimer/metabolismo , Amiloide/metabolismo , Animais , Encéfalo/metabolismo , Espinhas Dendríticas/efeitos dos fármacos , Espinhas Dendríticas/metabolismo , Modelos Animais de Doenças , Feminino , Gliose/patologia , Células HEK293 , Humanos , Camundongos Endogâmicos C57BL , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Presenilina-1/metabolismo , Anticorpos de Cadeia Única/metabolismo , Solubilidade , Sinapses/metabolismo
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