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1.
Neurotherapeutics ; 20(4): 1229-1240, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37296356

RESUMO

Recent evidence suggests that the glucagon-like peptide-1 receptor (GLP-1R) agonists have neuroprotective activities in the CNS in animal models of Parkinson's disease, Alzheimer's disease, and multiple sclerosis (MS). This study aimed to investigate whether a novel long-acting GLP-1R agonist, NLY01, could limit demyelination or improve remyelination as occurs in MS using the cuprizone (CPZ) mouse model. Herein, we assessed the expression of GLP-1R on oligodendrocytes in vitro and found that mature oligodendrocytes (Olig2+PDGFRa-) express GLP-1R. We further confirmed this observation in the brain by immunohistochemistry and found that Olig2+CC1+ cells express GLP-1R. We next administered NLY01 twice per week to C57B6 mice while on CPZ chow diet and found that NLY01 significantly reduced demyelination with greater weight loss than vehicle-treated controls. Because GLP-1R agonists are known to have anorexigenic effect, we then administered CPZ by oral gavage and treated the mice with NLY01 or vehicle to ensure the dose consistency of CPZ ingestion among mice. Using this modified approach, NLY01 was no longer effective in reducing demyelination of the corpus callosum (CC). We next sought to examine the effects of NLY01 treatment on remyelination after CPZ intoxication and during the recovery period using an adoptive transfer-CPZ (AT-CPZ) model. We found no significant differences between the NLY01 and vehicle groups in the amount of myelin or the number of mature oligodendrocytes in the CC. In summary, despite the promising anti-inflammatory and neuroprotective effects of GLP-1R agonists that have been previously described, our experiments provided no evidence to support a beneficial effect of NLY01 on limiting demyelination or enhancing remyelination. This information may be useful in selecting proper outcome measures in clinical trials of this promising class of drugs in MS.


Assuntos
Doenças Desmielinizantes , Esclerose Múltipla , Remielinização , Camundongos , Animais , Cuprizona/toxicidade , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/tratamento farmacológico , Bainha de Mielina , Esclerose Múltipla/metabolismo , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL
2.
J Clin Invest ; 133(7)2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36719741

RESUMO

Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease of the CNS. Increasing evidence suggests that vulnerable neurons in MS exhibit fatal metabolic exhaustion over time, a phenomenon hypothesized to be caused by chronic hyperexcitability. Axonal Kv7 (outward-rectifying) and oligodendroglial Kir4.1 (inward-rectifying) potassium channels have important roles in regulating neuronal excitability at and around the nodes of Ranvier. Here, we studied the spatial and functional relationship between neuronal Kv7 and oligodendroglial Kir4.1 channels and assessed the transcriptional and functional signatures of cortical and retinal projection neurons under physiological and inflammatory demyelinating conditions. We found that both channels became dysregulated in MS and experimental autoimmune encephalomyelitis (EAE), with Kir4.1 channels being chronically downregulated and Kv7 channel subunits being transiently upregulated during inflammatory demyelination. Further, we observed that pharmacological Kv7 channel opening with retigabine reduced neuronal hyperexcitability in human and EAE neurons, improved clinical EAE signs, and rescued neuronal pathology in oligodendrocyte-Kir4.1-deficient (OL-Kir4.1-deficient) mice. In summary, our findings indicate that neuron-OL compensatory interactions promoted resilience through Kv7 and Kir4.1 channels and identify pharmacological activation of nodal Kv7 channels as a neuroprotective strategy against inflammatory demyelination.


Assuntos
Encefalomielite Autoimune Experimental , Esclerose Múltipla , Camundongos , Animais , Humanos , Nós Neurofibrosos/metabolismo , Potássio/metabolismo , Neurônios/metabolismo , Oligodendroglia/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/metabolismo , Esclerose Múltipla/genética , Esclerose Múltipla/metabolismo
3.
Front Mol Neurosci ; 15: 995477, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36407761

RESUMO

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). In people with MS, impaired remyelination and axonal loss lead to debilitating long-term neurologic deficits. Current MS disease-modifying drugs mainly target peripheral immune cells and have demonstrated little efficacy for neuroprotection or promoting repair. To elucidate the pathological mechanisms and test therapeutic interventions, multiple animal models have been developed to recapitulate specific aspects of MS pathology, particularly the acute inflammatory stage. However, there are few animal models that facilitate the study of remyelination in the presence of inflammation, and none fully replicate the biology of chronic demyelination in MS. In this review, we describe the animal models that have provided insight into the mechanisms underlying demyelination, myelin repair, and potential therapeutic targets for remyelination. We highlight the limitations of studying remyelination in toxin-based demyelination models and discuss the combinatorial models that recapitulate the inflammatory microenvironment, which is now recognized to be a major inhibitor of remyelination mechanisms. These models may be useful in identifying novel therapeutics that promote CNS remyelination in inflammatory diseases such as MS.

4.
Caspian J Intern Med ; 13(Suppl 3): 155-160, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35872674

RESUMO

Women live longer than men. Cardiovascular disorders, cancers, and serious infectious conditions are less common among women than men. Recent data also indicate that women, particularly before menopause, are less susceptible to severe COVID-19, a viral infection hitting less-healthy individuals. The superiority of women regarding health has not been completely understood and partly been explained by estradiol beneficial effects on the microenvironment of the body, notably cytokine network. Estradiol cycles are aligned with menstruation cycles, a challenge for distinguishing their individual effects on human health. Large-scale, long-term studies indicate that hysterectomy, particularly at younger ages, is associated with an increased risk of mortality, cancer, or heart disorders. The underlying mechanisms for the increased risk in hysterectomized women are hard to be investigated in animal models since only a few primates menstruate. However, blood exchange models could resemble menstruation and provide some insight into possible beneficial effects of menstruation. Sera from animal models (neutral blood exchange) and also humans that have undergone therapeutic plasma exchange enhance the proliferation of progenitor cells in the culture and contain lower levels of proinflammatory factors. If menstruation resembles a blood exchange model, it can contribute to a healthier cytokine network in women. Consequently, menstruation, independently from estradiol health beneficial effects, can contribute to greater longevity and protection against certain disorders, e.g., COVID-19, in women. Investigation of COVID-19 rate/severity in hysterectomized women will provide insight into the possible beneficial effects of menstruation in COVID-19.

5.
Front Mol Neurosci ; 15: 874299, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35600072

RESUMO

Astrocytes are instrumental in maintaining central nervous system (CNS) homeostasis and responding to injury. A major limitation of studying neurodegenerative diseases like multiple sclerosis (MS) is lack of human pathological specimens obtained during the acute stages, thereby relegating research to post-mortem specimens obtained years after the initiation of pathology. Rodent reactive astrocytes have been shown to be cytotoxic to neurons and oligodendrocytes but may differ from human cells, especially in diseases with genetic susceptibility. Herein, we purified human CD49f+ astrocytes from induced pluripotent stem cells derived from individual patient and control peripheral leukocytes. We compared TNF and IL1α stimulated human reactive astrocytes from seven persons with MS and six non-MS controls and show their transcriptomes are remarkably similar to those described in rodents. The functional effect of astrocyte conditioned media (ACM) was examined in a human oligodendrocyte precursor cell (OPC) line differentiation assay. ACM was not cytotoxic to the OPCs but robustly inhibited the myelin basic protein (MBP) reporter. No differences were seen between MS and control stimulated astrocytes at either the transcript level or in ACM mediated OPC suppression assays. We next used RNAseq to interrogate differentially expressed genes in the OPC lines that had suppressed differentiation from the human ACM. Remarkably, not only was OPC differentiation and myelin gene expression suppressed, but we observed induction of several immune pathways in OPCs exposed to the ACM. These data support the notion that reactive astrocytes can inhibit OPC differentiation thereby limiting their remyelination capacity, and that OPCs take on an immune profile in the context of inflammatory cues.

6.
J Neuroimmunol ; 367: 577859, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35395486

RESUMO

Retinal ganglion cells (RGC) are lost as a sequela of optic nerve inflammation in myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD), but the mechanisms of injury remain incompletely understood and there remains a need to characterize the murine model of MOGAD. Several studies have shown that RGC loss occurs in association with optic neuritis in MOG35-55 experimental autoimmune encephalomyelitis (EAE), but retinal pathology has not been studied in the double transgenic opticospinal EAE (OSE) model, in which animals develop spontaneous disease associated with MOG35-55 peptide specific T cells and B cells producing MOG-specific antibodies. Herein, we show that at 8-weeks OSE mice develop optic nerve inflammation, reactive astrogliosis, and RGC loss. By 10-weeks of age, affected mice have a 50% reduction in RGCs as compared to age matched wild type mice without EAE. The retinal pathology that ensues from spontaneous optic neuritis in OSE mice mirrors that seen following human optic neuritis and may be a useful model for screening neuroprotective compounds for MOGAD and other diseases with optic neuritis.


Assuntos
Encefalomielite Autoimune Experimental , Neurite Óptica , Retina , Animais , Encefalomielite Autoimune Experimental/complicações , Doença de Hashimoto , Inflamação/patologia , Camundongos , Camundongos Endogâmicos C57BL , Glicoproteína Mielina-Oligodendrócito , Neurite Óptica/complicações , Retina/patologia
7.
Curr Opin Pharmacol ; 63: 102194, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35255453

RESUMO

Chronically demyelinated axons are rendered susceptible to degeneration through loss of trophic support from oligodendrocytes and myelin, and this process underlies disability progression in multiple sclerosis. Promoting remyelination is a promising neuroprotective therapeutic strategy, but to date, has not been achieved through simply promoting oligodendrocyte precursor cell differentiation, and it is clear that a detailed understanding of the molecular mechanisms underlying failed remyelination is required to guide future therapeutic approaches. In multiple sclerosis, remyelination is impaired by extrinsic inhibitory cues in the lesion microenvironment including secreted effector molecules released from compartmentalized immune cells and reactive glia, as well as by intrinsic defects in oligodendrocyte lineage cells, most notably increased metabolic demands causing oxidative stress and accelerated cellular senescence. Promising advances in our understanding of the cellular and molecular mechanisms underlying these processes offers hope for strategically designed interventions to facilitate remyelination thereby resulting in robust clinical benefits.


Assuntos
Esclerose Múltipla , Remielinização , Diferenciação Celular , Humanos , Esclerose Múltipla/metabolismo , Bainha de Mielina/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia
8.
Clin Case Rep ; 10(1): e05293, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35106163

RESUMO

Abnormal iron accumulation in vital organs is one of the major complications of ß-thalassemia intermedia (ß-TI). Silymarin, a flavonolignan isolated from Silybum marianum, significantly decreases the serum ferritin levels of ß-TI patients. This finding suggests silymarin as a safe and effective natural iron-chelating agent for the treatment of iron-overloaded conditions.

9.
Front Neurosci ; 15: 700253, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34594182

RESUMO

Mouse behavior is a primary outcome in evaluations of therapeutic efficacy. Exhaustive, continuous, multiparametric behavioral phenotyping is a valuable tool for understanding the pathophysiological status of mouse brain diseases. Automated home cage behavior analysis produces highly granulated data both in terms of number of features and sampling frequency. Previously, we demonstrated several ways to reduce feature dimensionality. In this study, we propose novel approaches for analyzing 33-Hz data generated by CleverSys software. We hypothesized that behavioral patterns within short time windows are reflective of physiological state, and that computer modeling of mouse behavioral routines can serve as a predictive tool in classification tasks. To remove bias due to researcher decisions, our data flow is indifferent to the quality, value, and importance of any given feature in isolation. To classify day and night behavior, as an example application, we developed a data preprocessing flow and utilized logistic regression (LG), support vector machines (SVM), random forest (RF), and one-dimensional convolutional neural networks paired with long short-term memory deep neural networks (1DConvBiLSTM). We determined that a 5-min video clip is sufficient to classify mouse behavior with high accuracy. LG, SVM, and RF performed similarly, predicting mouse behavior with 85% accuracy, and combining the three algorithms in an ensemble procedure increased accuracy to 90%. The best performance was achieved by combining the 1DConv and BiLSTM algorithms yielding 96% accuracy. Our findings demonstrate that computer modeling of the home-cage ethome can clearly define mouse physiological state. Furthermore, we showed that continuous behavioral data can be analyzed using approaches similar to natural language processing. These data provide proof of concept for future research in diagnostics of complex pathophysiological changes that are accompanied by changes in behavioral profile.

10.
Acta Neuropathol ; 142(5): 899-915, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34487221

RESUMO

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) characterized by varying degrees of secondary neurodegeneration. Retinal ganglion cells (RGC) are lost in MS in association with optic neuritis but the mechanisms of neuronal injury remain unclear. Complement component C3 has been implicated in retinal and cerebral synaptic pathology that may precede neurodegeneration. Herein, we examined post-mortem MS retinas, and then used a mouse model, experimental autoimmune encephalomyelitis (EAE), to examine the role of C3 in the pathogenesis of RGC loss associated with optic neuritis. First, we show extensive C3 expression in astrocytes (C3+/GFAP+ cells) and significant RGC loss (RBPMS+ cells) in post-mortem retinas from people with MS compared to retinas from non-MS individuals. A patient with progressive MS with a remote history of optic neuritis showed marked reactive astrogliosis with C3 expression in the inner retina extending into deeper layers in the affected eye more than the unaffected eye. To study whether C3 mediates retinal degeneration, we utilized global C3-/- EAE mice and found that they had less RGC loss and partially preserved neurites in the retina compared with C3+/+ EAE mice. C3-/- EAE mice had fewer axonal swellings in the optic nerve, reflecting reduced axonal injury, but had no changes in demyelination or T cell infiltration into the CNS. Using a C3-tdTomato reporter mouse line, we show definitive evidence of C3 expression in astrocytes in the retina and optic nerves of EAE mice. Conditional deletion of C3 in astrocytes showed RGC protection replicating the effects seen in the global knockouts. These data implicate astrocyte C3 expression as a critical mediator of retinal neuronal pathology in EAE and MS, and are consistent with recent studies showing C3 gene variants are associated with faster rates of retinal neurodegeneration in human disease.


Assuntos
Complemento C3/metabolismo , Esclerose Múltipla/patologia , Doenças Neuroinflamatórias/patologia , Células Ganglionares da Retina/patologia , Animais , Astrócitos/imunologia , Astrócitos/metabolismo , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/patologia , Humanos , Camundongos , Esclerose Múltipla/imunologia , Degeneração Neural/imunologia , Degeneração Neural/patologia , Doenças Neuroinflamatórias/imunologia , Nervo Óptico/patologia , Neurite Óptica/imunologia , Neurite Óptica/patologia
11.
Nature ; 597(7878): 709-714, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34497421

RESUMO

Multiple sclerosis (MS) lesions that do not resolve in the months after they form harbour ongoing demyelination and axon degeneration, and are identifiable in vivo by their paramagnetic rims on MRI scans1-3. Here, to define mechanisms underlying this disabling, progressive neurodegenerative state4-6 and foster development of new therapeutic agents, we used MRI-informed single-nucleus RNA sequencing to profile the edge of demyelinated white matter lesions at various stages of inflammation. We uncovered notable glial and immune cell diversity, especially at the chronically inflamed lesion edge. We define 'microglia inflamed in MS' (MIMS) and 'astrocytes inflamed in MS', glial phenotypes that demonstrate neurodegenerative programming. The MIMS transcriptional profile overlaps with that of microglia in other neurodegenerative diseases, suggesting that primary and secondary neurodegeneration share common mechanisms and could benefit from similar therapeutic approaches. We identify complement component 1q (C1q) as a critical mediator of MIMS activation, validated immunohistochemically in MS tissue, genetically by microglia-specific C1q ablation in mice with experimental autoimmune encephalomyelitis, and therapeutically by treating chronic experimental autoimmune encephalomyelitis with C1q blockade. C1q inhibition is a potential therapeutic avenue to address chronic white matter inflammation, which could be monitored by longitudinal assessment of its dynamic biomarker, paramagnetic rim lesions, using advanced MRI methods.


Assuntos
Astrócitos/patologia , Linfócitos/patologia , Microglia/patologia , Esclerose Múltipla/patologia , Animais , Encéfalo/patologia , Complemento C1q/antagonistas & inibidores , Complemento C1q/metabolismo , Encefalomielite Autoimune Experimental/patologia , Feminino , Humanos , Inflamação/patologia , Imageamento por Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico por imagem , RNA-Seq , Transcriptoma , Substância Branca/patologia
12.
Neurotherapeutics ; 18(3): 1834-1848, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34260042

RESUMO

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS), characterized by demyelination, gliosis, and neurodegeneration. While the currently available disease-modifying therapies effectively suppress the immune attack on the CNS, there are no therapies to date that directly mitigate neurodegeneration. Glucagon-like peptide-1 (GLP-1) is a small peptide hormone that maintains glucose homeostasis. A novel GLP-1 receptor (GLP-1R) agonist, NLY01, was recently shown to have neuroprotective effects in the animal models of Parkinson's disease and is now in a phase 2 clinical trial. In this study, we investigated the therapeutic potential of NLY01 in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Our data show that NLY01 delays the onset and attenuates the severity of EAE in a prevention paradigm, when given before disease onset. NLY01 inhibits the activation of immune cells in the spleen and reduces their trafficking into the CNS. In addition, we show that NLY01 suppresses the production of chemokines that are involved in leukocyte recruitment to the site of inflammation. The anti-inflammatory effect of NLY01 at the early stage of EAE may block the expression of the genes associated with neurotoxic astrocytes in the optic nerves, thereby preventing retinal ganglion cell (RGC) loss in the progressive stage of EAE. In the therapeutic paradigm, NLY01 significantly decreases the clinical score and second attack in a model of relapsing-remitting EAE. GLP-1R agonists may have dual efficacy in MS by suppressing peripheral and CNS inflammation, thereby limiting neuronal loss.


Assuntos
Encefalomielite Autoimune Experimental/tratamento farmacológico , Encefalomielite Autoimune Experimental/imunologia , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/imunologia , Fármacos Neuroprotetores/uso terapêutico , Animais , Encefalomielite Autoimune Experimental/metabolismo , Feminino , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fármacos Neuroprotetores/farmacologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo
13.
J Clin Invest ; 130(7): 3467-3482, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32182223

RESUMO

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the CNS. Bile acids are cholesterol metabolites that can signal through receptors on cells throughout the body, including in the CNS and the immune system. Whether bile acid metabolism is abnormal in MS is unknown. Using global and targeted metabolomic profiling, we identified lower levels of circulating bile acid metabolites in multiple cohorts of adult and pediatric patients with MS compared with controls. In white matter lesions from MS brain tissue, we noted the presence of bile acid receptors on immune and glial cells. To mechanistically examine the implications of lower levels of bile acids in MS, we studied the in vitro effects of an endogenous bile acid, tauroursodeoxycholic acid (TUDCA), on astrocyte and microglial polarization. TUDCA prevented neurotoxic (A1) polarization of astrocytes and proinflammatory polarization of microglia in a dose-dependent manner. TUDCA supplementation in experimental autoimmune encephalomyelitis reduced the severity of disease through its effects on G protein-coupled bile acid receptor 1 (GPBAR1). We demonstrate that bile acid metabolism was altered in MS and that bile acid supplementation prevented polarization of astrocytes and microglia to neurotoxic phenotypes and ameliorated neuropathology in an animal model of MS. These findings identify dysregulated bile acid metabolism as a potential therapeutic target in MS.


Assuntos
Astrócitos/metabolismo , Microglia/metabolismo , Esclerose Múltipla/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Ácido Tauroquenodesoxicólico , Animais , Astrócitos/patologia , Modelos Animais de Doenças , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Microglia/patologia , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/patologia , Ácido Tauroquenodesoxicólico/metabolismo , Ácido Tauroquenodesoxicólico/farmacologia
14.
PLoS Biol ; 17(9): e3000451, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31525189

RESUMO

Nucleotide-binding, leucine-rich repeat containing X1 (NLRX1) is a mitochondria-located innate immune sensor that inhibits major pro-inflammatory pathways such as type I interferon and nuclear factor-κB signaling. We generated a novel, spontaneous, and rapidly progressing mouse model of multiple sclerosis (MS) by crossing myelin-specific T-cell receptor (TCR) transgenic mice with Nlrx1-/- mice. About half of the resulting progeny developed spontaneous experimental autoimmune encephalomyelitis (spEAE), which was associated with severe demyelination and inflammation in the central nervous system (CNS). Using lymphocyte-deficient mice and a series of adoptive transfer experiments, we demonstrate that genetic susceptibility to EAE lies within the innate immune compartment. We show that NLRX1 inhibits the subclinical stages of microglial activation and prevents the generation of neurotoxic astrocytes that induce neuronal and oligodendrocyte death in vitro. Moreover, we discovered several mutations within NLRX1 that run in MS-affected families. In summary, our findings highlight the importance of NLRX1 in controlling the early stages of CNS inflammation and preventing the onset of spontaneous autoimmunity.


Assuntos
Encefalomielite Autoimune Experimental/etiologia , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/fisiologia , Adulto , Animais , Astrócitos/fisiologia , Estudos de Casos e Controles , Sistema Nervoso Central/patologia , Códon sem Sentido , Doenças Desmielinizantes , Encefalomielite Autoimune Experimental/patologia , Feminino , Humanos , Imunidade Inata , Masculino , Camundongos Transgênicos , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Adulto Jovem
15.
J Pharmacol Exp Ther ; 370(3): 437-446, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31248979

RESUMO

Multiple sclerosis is a neurodegenerative disease affecting predominantly female patients between 20 and 45 years of age. We previously reported the significant contribution of mouse mast cell protease 4 (mMCP-4) in the synthesis of endothelin-1 (ET-1) in healthy mice and in a murine model of experimental autoimmune encephalomyelitis (EAE). In the current study, the cardiovascular effects of ET-1 and big endothelin-1 (big-ET-1) administered systemically or intrathecally were assessed in the early preclinical phase of EAE in telemetry instrumented/conscious mice. Chymase-specific enzymatic activity was also measured in the lung, brain, and mast cell extracts in vitro. Finally, the impact of EAE immunization was studied on the pulmonary and brain mRNA expression of different genes of the endothelin pathway, interleukin-33 (IL-33), and monitoring of immunoreactive tumor necrosis factor-α (TNF-α). Systemically or intrathecally administered big-ET-1 triggered increases in blood pressure in conscious mice. One week post-EAE, the pressor responses to big-ET-1 were potentiated in wild-type (WT) mice but not in mMCP-4 knockout (KO) mice. EAE triggered mMCP-4-specific activity in cerebral homogenates and peritoneal mast cells. Enhanced pulmonary, but not cerebral preproendothelin-1 and IL-33 mRNA were found in KO mice and further increased 1 week post-EAE immunization, but not in WT animals. Finally, TNF-α levels were also increased in serum from mMCP-4 KO mice, but not WT, 1 week post-EAE. Our study suggests that mMCP-4 activity is enhanced both centrally and systemically in a mouse model of EAE.


Assuntos
Encefalomielite Autoimune Experimental/metabolismo , Endotelina-1/administração & dosagem , Endotelina-1/farmacologia , Serina Endopeptidases/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/patologia , Encefalomielite Autoimune Experimental/fisiopatologia , Técnicas de Inativação de Genes , Hemodinâmica/efeitos dos fármacos , Injeções Espinhais , Interleucina-33/deficiência , Interleucina-33/genética , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Mastócitos/efeitos dos fármacos , Mastócitos/metabolismo , Camundongos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Serina Endopeptidases/deficiência , Serina Endopeptidases/genética , Regulação para Cima/efeitos dos fármacos
16.
Cells ; 8(5)2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31052241

RESUMO

Uptake of glutamate from the extracellular space and glutamate release to neurons are two major processes conducted by astrocytes in the central nervous system (CNS) that protect against glutamate excitotoxicity and strengthen neuronal firing, respectively. During inflammatory conditions in the CNS, astrocytes may lose one or both of these functions, resulting in accumulation of the extracellular glutamate, which eventually leads to excitotoxic neuronal death, which in turn worsens the CNS inflammation. NLRX1 is an innate immune NOD-like receptor that inhibits the major inflammatory pathways. It is localized in the mitochondria and was shown to inhibit cell death, enhance ATP production, and dampen oxidative stress. In the current work, using primary murine astrocyte cultures from WT and Nlrx1-/- mice, we demonstrate that NLRX1 potentiates astrocytic glutamate uptake by enhancing mitochondrial functions and the functional activity of glutamate transporters. Also, we report that NLRX1 inhibits glutamate release from astrocytes by repressing Ca2+-mediated glutamate exocytosis. Our study, for the first time, identified NLRX1 as a potential regulator of glutamate homeostasis in the CNS.


Assuntos
Astrócitos/metabolismo , Ácido Glutâmico/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/fisiologia , Animais , Astrócitos/citologia , Transporte Biológico , Células Cultivadas , Sistema Nervoso Central/metabolismo , Proteínas de Transporte de Glutamato da Membrana Plasmática/fisiologia , Homeostase , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD
17.
Cells ; 8(2)2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30791579

RESUMO

Glutamate is one of the most prevalent neurotransmitters released by excitatory neurons in the central nervous system (CNS); however, residual glutamate in the extracellular space is, potentially, neurotoxic. It is now well-established that one of the fundamental functions of astrocytes is to uptake most of the synaptically-released glutamate, which optimizes neuronal functions and prevents glutamate excitotoxicity. In the CNS, glutamate clearance is mediated by glutamate uptake transporters expressed, principally, by astrocytes. Interestingly, recent studies demonstrate that extracellular glutamate stimulates Ca2+ release from the astrocytes' intracellular stores, which triggers glutamate release from astrocytes to the adjacent neurons, mostly by an exocytotic mechanism. This released glutamate is believed to coordinate neuronal firing and mediate their excitatory or inhibitory activity. Therefore, astrocytes contribute to glutamate homeostasis in the CNS, by maintaining the balance between their opposing functions of glutamate uptake and release. This dual function of astrocytes represents a potential therapeutic target for CNS diseases associated with glutamate excitotoxicity. In this regard, we summarize the molecular mechanisms of glutamate uptake and release, their regulation, and the significance of both processes in the CNS. Also, we review the main features of glutamate metabolism and glutamate excitotoxicity and its implication in CNS diseases.


Assuntos
Astrócitos/metabolismo , Sistema Nervoso Central/metabolismo , Ácido Glutâmico/metabolismo , Homeostase , Proteínas de Transporte de Glutamato da Membrana Plasmática/metabolismo , Humanos , Modelos Biológicos
18.
Mult Scler Relat Disord ; 26: 19-32, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30216755

RESUMO

INTRODUCTION: Vascular comorbidities are prevalent among people with multiple sclerosis (MS) and have adverse disease-related consequences. In the general population, physical activity (PA) and exercise training have proven beneficial at all levels of vascular disease risk management. People with MS exhibit particularly low rates of PA; therefore, PA represents a modifiable health behavior for potentially managing vascular comorbidity risk in MS, and in turn, reducing disease burden. However, points of evidence justifying such an approach have yet to be summarized. OBJECTIVE: To conduct a scoping review of existing evidence linking PA and exercise training to potential modification of vascular comorbidities and related risk factors in people with MS. METHODS: We searched five electronic databases (PubMed, Ovid MEDLINE, Embase, PsycINFO, and CINAHL Plus) from inception to November 2017, for articles involving relevant vascular comorbidities (obesity, hyperlipidemia, heart disease, hypertension, and diabetes) in people with MS in conjunction with measures of PA, physical fitness, sedentary behavior, or exercise training. Studies were limited to English-language and primary research articles. Data were extracted and summarized by comorbidity type and study design (observational vs. interventional). RESULTS: Our initial search identified 1028 articles; subsequent screening resulted in 34 articles meeting the final inclusion criteria, including both observational (n = 17) and interventional (n = 17) studies. Most of the articles reported on obesity (n = 29), although evidence surrounding hyperlipidemia (n = 5), arterial function and hypertension (n = 5), and diabetes (n = 5) was also identified. Data supporting a beneficial role for PA or exercise training could be drawn from each comorbidity category. Overall, 14 of the 17 observational studies identified (82.4%) reported an association between higher levels of PA or cardiorespiratory fitness, or decreased sedentary behavior, and better function of at least one risk factor related to vascular comorbid conditions in people with MS. The efficacy of exercise training in limiting vascular comorbidity risk and burden was dependent upon intervention type and duration, with 9 of 17 interventional studies (52.9%) reporting improvement in at least one relevant measure of vascular comorbidity in participants with MS. CONCLUSIONS: Evidence points to a potential relationship between PA and exercise and risk factors related to vascular comorbidities in people with MS. PA and exercise training interventions may represent an effective therapeutic strategy for managing vascular comorbidities in people with MS, justifying further investigation.


Assuntos
Comorbidade , Terapia por Exercício , Exercício Físico , Esclerose Múltipla/reabilitação , Doenças Vasculares/reabilitação , Terapia por Exercício/estatística & dados numéricos , Humanos , Esclerose Múltipla/epidemiologia , Doenças Vasculares/epidemiologia
19.
Front Behav Neurosci ; 12: 187, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30214401

RESUMO

Using automated supervised behavioral assessment software, we recorded and analyzed 24 h non-interrupted recordings of mice for a duration of 11 days. With the assistance of free R programming, we used correlation matrix-based hierarchical clustering and factor analysis to separate the 33 activities into meaningful clusters and groups without losing the exhaustive nature of the findings. These groups represent novel meaningful behavioral patterns exhibited by mice in home cage. Thirty-three activities were separated into 5 clusters based on dissimilarity between activities and 6 factors based on statistical modeling. Using these two methods, we describe and compare behavioral arrays of two groups of animals: 1. Continuously recorded for 11 days in social isolation and 2. Intermittently socially isolated for recording on days 1, 3, 5, 8, and 10, while socializing on the other days. This is the first work to our knowledge that interprets mouse home cage activities throughout a 24 h period and proposes a base line of a daily routine of a healthy C57Bl/6J mouse that can be used for various experimental paradigms, including disease, neuroinflammation, or drug testing to trace behavioral changes that follow intervention. In this work, we defined the necessary acclimatization period for the 24 h recording paradigm of home cage behavior. We demonstrated the behavioral changes that are associated with the effect of social isolation, intermittent socialization, and re-introduction to a familiar home cage. We provide the full description of the codes used in R.

20.
Cells ; 7(9)2018 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-30150571

RESUMO

Although the etiology of multiple sclerosis (MS) remains enigmatic, the role of T cells is unquestionably central in this pathology. Immune cells respond to pathogens and danger signals via pattern-recognition receptors (PRR). Several reports implicate Nlrp12, an intracellular PRR, in the development of a mouse MS-like disease, called Experimental Autoimmune Encephalomyelitis (EAE). In this study, we used induced and spontaneous models of EAE, as well as in vitro T cell assays, to test the hypothesis that Nlrp12 inhibits Th1 response and prevents T-cell mediated autoimmunity. We found that Nlrp12 plays a protective role in induced EAE by reducing IFNγ/IL-4 ratio in lymph nodes, whereas it potentiates the development of spontaneous EAE (spEAE) in 2D2 T cell receptor (TCR) transgenic mice. Looking into the mechanism of Nlrp12 activity in T cell response, we found that it inhibits T cell proliferation and suppresses Th1 response by reducing IFNγ and IL-2 production. Following TCR activation, Nlrp12 inhibits Akt and NF-κB phosphorylation, while it has no effect on S6 phosphorylation in the mTOR pathway. In conclusion, we propose a model that can explain the dual immunoregulatory function of Nlrp12 in EAE. We also propose a model explaining the molecular mechanism of Nlrp12-dependent regulation of T cell response.

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