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1.
PLoS Genet ; 16(8): e1008752, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32790717

RESUMO

Myelin is composed of plasma membrane spirally wrapped around axons and compacted into dense sheaths by myelin-associated proteins. Myelin is elaborated by neuroepithelial derived oligodendrocytes in the central nervous system (CNS) and by neural crest derived Schwann cells in the peripheral nervous system (PNS). While some myelin proteins accumulate in only one lineage, myelin basic protein (Mbp) is expressed in both. Overlapping the Mbp gene is Golli, a transcriptional unit that is expressed widely both within and beyond the nervous system. A super-enhancer domain within the Golli/Mbp locus contains multiple enhancers shown previously to drive reporter construct expression specifically in oligodendrocytes or Schwann cells. In order to determine the contribution of each enhancer to the Golli/Mbp expression program, and to reveal if functional interactions occur among them, we derived mouse lines in which they were deleted, either singly or in different combinations, and relative mRNA accumulation was measured at key stages of early development and at maturity. Although super-enhancers have been shown previously to facilitate interaction among their component enhancers, the enhancers investigated here demonstrated largely additive relationships. However, enhancers demonstrating autonomous activity strictly in one lineage, when missing, were found to significantly reduce output in the other, thus revealing cryptic "stealth" activity. Further, in the absence of a key oligodendrocyte enhancer, Golli accumulation was markedly and uniformly attenuated in all cell types investigated. Our observations suggest a model in which enhancer-mediated DNA-looping and potential super-enhancer properties underlie Golli/Mbp regulatory organization.


Assuntos
Elementos Facilitadores Genéticos , Proteína Básica da Mielina/genética , Animais , Camundongos , Camundongos Endogâmicos C57BL , Proteína Básica da Mielina/metabolismo , Neurogênese , Oligodendroglia/citologia , Oligodendroglia/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Células de Schwann/citologia , Células de Schwann/metabolismo , Medula Espinal/citologia , Medula Espinal/embriologia , Medula Espinal/metabolismo
2.
Proc Natl Acad Sci U S A ; 117(33): 20088-20099, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32732436

RESUMO

T lymphocyte motility and interaction dynamics with other immune cells are vital determinants of immune responses. Regulatory T (Treg) cells prevent autoimmune disorders by suppressing excessive lymphocyte activity, but how interstitial motility patterns of Treg cells limit neuroinflammation is not well understood. We used two-photon microscopy to elucidate the spatial organization, motility characteristics, and interactions of endogenous Treg and Th17 cells together with antigen-presenting cells (APCs) within the spinal cord leptomeninges in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Th17 cells arrive before the onset of clinical symptoms, distribute uniformly during the peak, and decline in numbers during later stages of EAE. In contrast, Treg cells arrive after Th17 cells and persist during the chronic phase. Th17 cells meander widely, interact with APCs, and exhibit cytosolic Ca2+ transients and elevated basal Ca2+ levels before the arrival of Treg cells. In contrast, Treg cells adopt a confined, repetitive-scanning motility while contacting APCs. These locally confined but highly motile Treg cells limit Th17 cells from accessing APCs and suppress Th17 cell Ca2+ signaling by a mechanism that is upstream of store-operated Ca2+ entry. Finally, Treg cell depletion increases APC numbers in the spinal cord and exaggerates ongoing neuroinflammation. Our results point to fundamental differences in motility characteristics between Th17 and Treg cells in the inflamed spinal cord and reveal three potential cellular mechanisms by which Treg cells regulate Th17 cell effector functions: reduction of APC density, limiting access of Th17 cells to APCs, and suppression of Th17 Ca2+ signaling.


Assuntos
Sinalização do Cálcio/fisiologia , Medula Espinal/metabolismo , Células Th17/metabolismo , Animais , Autoantígenos , Feminino , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Proteínas de Fluorescência Verde , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Bainha de Mielina , Linfócitos T Reguladores
3.
Proc Natl Acad Sci U S A ; 117(30): 18037-18048, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32641508

RESUMO

Axon-axon interactions are essential for axon guidance during nervous system wiring. However, it is unknown whether and how the growth cones communicate with each other while sensing and responding to guidance cues. We found that the Parkinson's disease gene, leucine-rich repeat kinase 2 (LRRK2), has an unexpected role in growth cone-growth cone communication. The LRRK2 protein acts as a scaffold and induces Frizzled3 hyperphosphorylation indirectly by recruiting other kinases and also directly phosphorylates Frizzled3 on threonine 598 (T598). In LRRK1 or LRRK2 single knockout, LRRK1/2 double knockout, and LRRK2 G2019S knockin, the postcrossing spinal cord commissural axons are disorganized and showed anterior-posterior guidance errors after midline crossing. Growth cones from either LRRK2 knockout or G2019S knockin mice showed altered interactions, suggesting impaired communication. Intercellular interaction between Frizzled3 and Vangl2 is essential for planar cell polarity signaling. We show here that this interaction is regulated by phosphorylation of Frizzled3 at T598 and can be regulated by LRRK2 in a kinase activity-dependent way. In the LRRK1/2 double knockout or LRRK2 G2019S knockin, the dopaminergic axon bundle in the midbrain was significantly widened and appeared disorganized, showing aberrant posterior-directed growth. Our findings demonstrate that LRRK2 regulates growth cone-growth cone communication in axon guidance and that both loss-of-function mutation and a gain-of-function mutation (G2019S) cause axon guidance defects in development.


Assuntos
Axônios/metabolismo , Receptores Frizzled/metabolismo , Cones de Crescimento/metabolismo , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/genética , Neurogênese/genética , Transdução de Sinais , Animais , Neurônios Dopaminérgicos/citologia , Neurônios Dopaminérgicos/metabolismo , Técnicas de Silenciamento de Genes , Humanos , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Camundongos , Modelos Biológicos , Mutação , Neurônios/metabolismo , Fosforilação , Medula Espinal/citologia , Medula Espinal/metabolismo
4.
Proc Natl Acad Sci U S A ; 117(30): 18018-18028, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32651278

RESUMO

CCN3 is a matricellular protein that promotes oligodendrocyte progenitor cell differentiation and myelination in vitro and ex vivo. CCN3 is therefore a candidate of interest in central nervous system (CNS) myelination and remyelination, and we sought to investigate the expression and role of CCN3 during these processes. We found CCN3 to be expressed predominantly by neurons in distinct areas of the CNS, primarily the cerebral cortex, hippocampus, amygdala, suprachiasmatic nuclei, anterior olfactory nuclei, and spinal cord gray matter. CCN3 was transiently up-regulated following demyelination in the brain of cuprizone-fed mice and spinal cord lesions of mice injected with lysolecithin. However, CCN3-/- mice did not exhibit significantly different numbers of oligodendroglia or differentiated oligodendrocytes in the healthy or remyelinating CNS, compared to WT controls. These results suggest that despite robust and dynamic expression in the CNS, CCN3 is not required for efficient myelination or remyelination in the murine CNS in vivo.


Assuntos
Sistema Nervoso Central/metabolismo , Doenças Desmielinizantes/etiologia , Regulação da Expressão Gênica , Proteína Sobre-Expressa em Nefroblastoma/genética , Remielinização/genética , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Imunofluorescência , Camundongos , Bainha de Mielina/metabolismo , Proteína Sobre-Expressa em Nefroblastoma/metabolismo , Células Precursoras de Oligodendrócitos/metabolismo , Oligodendroglia/metabolismo , Medula Espinal/metabolismo , Medula Espinal/patologia
5.
Life Sci ; 260: 118098, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32679145

RESUMO

AIMS: Spinal cord injury (SCI) is one of the most devastating diseases that challenges neurology and medicine, leading to paraplegia or quadriplegia worldwide. Neuroprotection conferred by histone deacetylase (HDAC) inhibitors against various insults and deficits in the central nervous system has been reported previously. Herein, we set out to ascertain whether HDAC3 inhibition exerts neuroprotective effects against SCI. MAIN METHODS: A modified Allen's weight-drop method was performed to induce experimental SCI in rats. Basso-Beattie-Bresnahan (BBB) scores were used to assess locomotor function. Flow cytometric analysis of AnnexinV-FITC/PI double staining, TUNEL staining, and immunoblotting analysis of apoptosis-related proteins were performed to determine apoptosis in H2O2-induced cell injury of primary rat neurons. KEY FINDINGS: Upregulated HDAC3 and downregulated miR-27a were observed in spinal cord tissues of SCI rats and H2O2-injured neurons. HDAC3 knockdown by its specific shRNA restored the locomotor function of SCI rats and prevented rat neurons from H2O2-induced apoptosis through promotion of miR-27a. miR-27a targeted PAK6 (encoding P21-activated kinase 6) and inhibited its expression. The effects of HDAC3 knockdown on the locomotor function of SCI rats and H2O2-induced apoptosis of rat neurons were lost upon further PAK6 overexpression. SIGNIFICANCE: The present study uncovers that silencing HDAC3 inhibited PAK6 expression by upregulating miR-27a, eventually inhibiting neuron apoptosis and promoting the recovery of SCI, which might provide a novel therapeutic target for SCI.


Assuntos
Inativação Gênica , Histona Desacetilases/genética , MicroRNAs/genética , Traumatismos da Medula Espinal/terapia , Quinases Ativadas por p21/genética , Animais , Apoptose/fisiologia , Modelos Animais de Doenças , Citometria de Fluxo , Expressão Gênica/fisiologia , Peróxido de Hidrogênio/farmacologia , Marcação In Situ das Extremidades Cortadas , Locomoção/fisiologia , Masculino , MicroRNAs/fisiologia , Neurônios/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Medula Espinal/metabolismo , Regulação para Cima , Quinases Ativadas por p21/antagonistas & inibidores
6.
Toxicol Lett ; 331: 152-158, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32522579

RESUMO

Chronic exposure to n-hexane, a widely used solvent in industry, causes sensorimotor neuropathy, which is mainly mediated by its toxic metabolite, 2,5-hexanedione (HD). However, the mechanisms remain unclear. This study is designed to investigate whether nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is involved in HD-induced neurotoxicity. Results showed that HD intoxication significantly elevated NLRP3 expression, caspase-1 activation and interleukin-1ß (IL-1ß) maturation in the spinal cord of rats, indicating NLRP3 inflammasome activation. Glibenclamide, a sulfonylurea inhibitor of NLRP3 inflammasome, reduced HD-induced NLRP3 inflammasome activation, which was associated with mitigated gasdermin D (GSDMD) cleavage, neurofilament protein L (NF-L) reduction and demyelination as well as axon degeneration in the spinal cord of rats. Subsequently, we found that inhibition of NLRP3 inflammasome by glibenclamide suppressed microglial activation and M1 polarization and simultaneously recovered M2 polarization in HD-intoxicated rats. Furthermore, glibenclamide treatment reduced the contents of malondialdehyde (MDA) as well as elevated glutathione (GSH) levels and total-antioxidative capacity in the spinal cord of HD-intoxicated rats, indicating attenuated oxidative stress. Collectively, our findings suggested that NLRP3 inflammasome activation contributed to HD-induced neurotoxicity by enhancing microglial M1 polarization and oxidative damage. Inhibition of NLRP3 inflammasome by glibenclamide might a potential avenue to combat n-hexane-induced neuropathy.


Assuntos
Glibureto/farmacologia , Hexanonas/toxicidade , Inflamassomos/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/prevenção & controle , Estresse Oxidativo/efeitos dos fármacos , Medula Espinal/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Masculino , Síndromes Neurotóxicas/imunologia , Síndromes Neurotóxicas/metabolismo , Estresse Oxidativo/imunologia , Ratos Sprague-Dawley , Medula Espinal/imunologia , Medula Espinal/metabolismo
7.
PLoS One ; 15(6): e0235110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584865

RESUMO

Programmed axonal degeneration, also known as Wallerian degeneration, occurs in immune-mediated central nervous system (CNS) inflammatory disorders such as multiple sclerosis and the animal model experimental allergic encephalomyelitis (EAE). Sterile alpha and TIR domain containing protein 1 (SARM1) functions to promote programmed axonal degeneration. To test the hypothesis that loss of SARM1 will reduce axonal degeneration in immune-mediated CNS inflammatory disorders, the course and pathology of EAE was compared in Sarm1 knockout mice and wild type littermates. The clinical course of EAE was similar in Sarm1 knockout and wild type. Analysis of EAE in mice expressing neuronal yellow fluorescent protein (YFP) showed significantly less axonal degeneration in Sarm1 knockout mice compared to wild type littermates at 14 days post-induction of EAE. At 21 days post-induction, however, difference in axonal degeneration was not significant. At 42 days post-induction, Sarm1 knockout mice were indistinguishable from wild type with respect to markers of axonal injury, and were similar with respect to axonal density in the lumbar cords. There was no significant change in peripheral immune activation or CNS inflammatory cell infiltration associated with EAE in Sarm1 knockout mice. In conclusion, Sarm1 deletion delayed axonal degeneration early in the course of CNS inflammation, but did not confer long-term protection from axonal degeneration in an animal model of immune-mediated CNS inflammation.


Assuntos
Proteínas do Domínio Armadillo , Axônios , Proteínas do Citoesqueleto , Encefalomielite Autoimune Experimental , Técnicas de Inativação de Genes , Medula Espinal , Animais , Proteínas do Domínio Armadillo/genética , Proteínas do Domínio Armadillo/metabolismo , Axônios/metabolismo , Axônios/patologia , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/patologia , Encefalomielite Autoimune Experimental/prevenção & controle , Camundongos , Camundongos Knockout , Medula Espinal/metabolismo , Medula Espinal/patologia , Fatores de Tempo
8.
Nat Commun ; 11(1): 3052, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32546780

RESUMO

Itch, in particular chronic forms, has been widely recognized as an important clinical problem, but much less is known about the mechanisms of itch in comparison with other sensory modalities such as pain. Recently, considerable progress has been made in dissecting the circuit mechanisms of itch at both the spinal and supraspinal levels. Major components of the spinal neural circuit underlying both chemical and mechanical itch have now been identified, along with the circuits relaying ascending transmission and the descending modulation of itch. In this review, we summarize the progress in elucidating the neural circuit mechanism of itch at spinal and supraspinal levels.


Assuntos
Encéfalo/metabolismo , Prurido/etiologia , Animais , Peptídeo Liberador de Gastrina/genética , Peptídeo Liberador de Gastrina/metabolismo , Humanos , Neurônios/patologia , Neurônios/fisiologia , Prurido/psicologia , Receptores da Bombesina/genética , Receptores da Bombesina/metabolismo , Transdução de Sinais , Medula Espinal/metabolismo
10.
Acta Cir Bras ; 35(3): e202000301, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401830

RESUMO

PURPOSE: To analyze the serum levels of nitric oxide and correlate them with the levels of thiobarbituric acid reactive substances (TBARS) in liver, brain and spinal cord of animals using L-NAME and treated with hydroxyurea. METHODS: Eighteen male albino Wistar rats were divided into three groups. NG-nitro-L-arginine methyl ester (L-NAME) was intraperitoneally administered to induce oxidative stress. TBARS and plasma nitric oxide levels were analyzed in all groups. Histopathology of the liver and vascular tissue was performed. RESULTS: Statistically significant differences were seen in liver, brain and spinal cord TBARS levels. CONCLUSIONS: Following the use of L-NAME, hepatic tissue increased the number of Kupffer cells as oxidative stress and inflammatory response increased. The use of L-NAME caused an increase in lipid peroxidation products and, consequently, in oxidative stress in animals. Hydroxyurea doses of 35 mg / kg / day reduced TBARS values in liver, brain and spinal cord.


Assuntos
Anemia Falciforme/tratamento farmacológico , Encéfalo/metabolismo , Hidroxiureia/uso terapêutico , Fígado/metabolismo , Estresse Oxidativo/fisiologia , Medula Espinal/metabolismo , Anemia Falciforme/metabolismo , Anemia Falciforme/fisiopatologia , Animais , Modelos Animais de Doenças , Masculino , NG-Nitroarginina Metil Éster , Ratos , Ratos Wistar
11.
Anesth Analg ; 130(6): 1638-1652, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32384350

RESUMO

One of the most prevalent symptoms after major surgery is pain. When postoperative pain treatment is unsatisfactory, it can lead to poor surgical recovery, decreased quality of life, and increased health care costs. Current analgesics, single or in combination, have limited efficacy due to low potency, limited duration of action, toxicities, and risk of addiction. The lack of nonaddictive strong analgesics along with the over prescription of opioids has led to an opioid epidemic in the United States. Therefore, there is an urgent need for the development of newer analgesics. Microribonucleic acids (miRNAs) are small noncoding RNA molecules that modulate protein synthesis in neurons and supporting cells (glia, leukocytes, and Schwann cells). The literature indicates that miRNA regulation is important in nociception. Here, we summarize the current evidence on the role of miRNAs on mechanisms involved in incisional, inflammatory, neuropathic, and cancer pain. We also discuss the role of modulating miRNA functions as potential therapeutic targets for analgesic use and opioid tolerance. Finally, we propose how the delivery of analog miRNAs (mimic-miRNAs or antago-miRNAs) could be introduced into clinical practice to provide analgesia in the perioperative period.


Assuntos
MicroRNAs/metabolismo , Dor Pós-Operatória/genética , Dor Pós-Operatória/metabolismo , Dor Aguda/genética , Dor Aguda/metabolismo , Dor Aguda/terapia , Analgesia , Analgésicos/administração & dosagem , Analgésicos Opioides/uso terapêutico , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Dor do Câncer/terapia , Tolerância a Medicamentos , Epigênese Genética , Custos de Cuidados de Saúde , Humanos , Inflamação , Manejo da Dor/métodos , Medição da Dor , Dor Pós-Operatória/terapia , Período Perioperatório , Qualidade de Vida , Medula Espinal/metabolismo
12.
Pain Res Manag ; 2020: 1854363, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32351637

RESUMO

Objective: Neuropathic pain with complex mechanisms has become a major public health problem that greatly impacts patients' quality of life. Therefore, novel and more effective strategies against neuropathic pain need further investigation. Electroacupuncture (EA) has an ameliorating effect on neuropathic pain following spared nerve injury (SNI), but the underlying mechanism remains to be fully clarified. Interferon regulatory factor 8 (IRF8), a critical transcription factor, was reported to be involved in the modulation of neuropathic pain. Here, we focused on exploring whether 2 Hz EA stimulation exerts an inhibitory action on spinal IRF8 in SNI rats. Methods: In this study, SNI rats were treated with 2 Hz EA once every other day for 21 days. Paw withdrawal threshold (PWT) was applied to determine the analgesic effect of 2 Hz EA on SNI rats. The spinal IRF8 and CX3CRl expressions were detected with qRT-PCR and western blot, and immunofluorescence staining was used to evaluate colocation of IRF8 or CX3CRl with microglial activation marker CD11b in the spinal cord. Results: It was found that SNI induced significant elevation of spinal IRF8 and CX3CRl mRNA and protein expression. Additionally, immunofluorescence results showed that SNI elicited the coexpression of IRF8 with CD11b, as well as CX3CRl with CD11b in the spinal cord. Meanwhile, 2 Hz EA treatment of SNI rats not only reduced IRF8 and CX3CRl mRNA and protein expression, but also reversed the coexpression of IRF8 or CX3CRl with CD11b in the spinal cord, along with an attenuation of SNI-evoked mechanical hypersensitivity. Conclusion: This experiment highlighted that 2 Hz EA can inhibit IRF8 expression and microglial activation in the spinal cord of SNI rats. Hence, targeting IRF8 may be a promising therapeutic strategy for 2 Hz EA treatment of neuropathic pain.


Assuntos
Eletroacupuntura , Fatores Reguladores de Interferon/metabolismo , Neuralgia/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Medula Espinal/metabolismo , Animais , Masculino , Ratos , Ratos Sprague-Dawley
13.
Muscle Nerve ; 62(2): 272-283, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32369618

RESUMO

BACKGROUND: The exact mechanisms underlying neuroinflammation and how they contribute to amyotrophic lateral sclerosis (ALS) pathogenesis remain unclear. One possibility is the secretion of neurotoxic factors, such as lipocalin-2 (LCN2), that lead to neuronal death. METHODS: LCN2 levels were measured in human postmortem tissue using Western blot, quantitative real time polymerase chain reaction, and immunofluorescence, and in plasma by enzyme-linked immunosorbent assay. SH-SY5Y cells were used to test the pro-inflammatory effects of LCN2. RESULTS: LCN2 is increased in ALS postmortem motor cortex, spinal cord, and plasma. Furthermore, we identified several LCN2 variants in ALS patients that may contribute to disease pathogenesis. Lastly, while LCN2 treatment caused cell death and increased pro-inflammatory markers, treatment with an anti-LCN2 antibody prevented these responses in vitro. CONCLUSIONS: LCN2 upregulation in ALS postmortem samples and plasma may be an upstream event for triggering neuroinflammation and neuronal death.


Assuntos
Esclerose Amiotrófica Lateral/genética , Inflamação/metabolismo , Lipocalina-2/genética , Córtex Motor/metabolismo , Medula Espinal/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/fisiopatologia , Western Blotting , Estudos de Casos e Controles , Morte Celular , Linhagem Celular Tumoral , Citocinas/efeitos dos fármacos , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Humanos , Técnicas In Vitro , Lipocalina-2/antagonistas & inibidores , Lipocalina-2/metabolismo , Lipocalina-2/farmacologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Reação em Cadeia da Polimerase em Tempo Real
14.
Proc Natl Acad Sci U S A ; 117(20): 11126-11135, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32371484

RESUMO

While several studies have shown that hypoxic preconditioning suppresses development of the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS), no one has yet examined the important clinically relevant question of whether mild hypoxia can impact the progression of preexisting disease. Using a relapsing-remitting model of EAE, here we demonstrate that when applied to preexisting disease, chronic mild hypoxia (CMH, 10% O2) markedly accelerates clinical recovery, leading to long-term stable reductions in clinical score. At the histological level, CMH led to significant reductions in vascular disruption, leukocyte accumulation, and demyelination. Spinal cord blood vessels of CMH-treated mice showed reduced expression of the endothelial activation molecule VCAM-1 but increased expression of the endothelial tight junction proteins ZO-1 and occludin, key mechanisms underlying vascular integrity. Interestingly, while equal numbers of inflammatory leukocytes were present in the spinal cord at peak disease (day 14 postimmunization; i.e., 3 d after CMH started), apoptotic removal of infiltrated leukocytes during the remission phase was markedly accelerated in CMH-treated mice, as determined by increased numbers of monocytes positive for TUNEL and cleaved caspase-3. The enhanced monocyte apoptosis in CMH-treated mice was paralleled by increased numbers of HIF-1α+ monocytes, suggesting that CMH enhances monocyte removal by amplifying the hypoxic stress manifest within monocytes in acute inflammatory lesions. These data demonstrate that mild hypoxia promotes recovery from preexisting inflammatory demyelinating disease and suggest that this protection is primarily the result of enhanced vascular integrity and accelerated apoptosis of infiltrated monocytes.


Assuntos
Apoptose/fisiologia , Encefalomielite Autoimune Experimental , Hipóxia/metabolismo , Monócitos/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Caspase 3 , Modelos Animais de Doenças , Endotélio/metabolismo , Feminino , Camundongos , Esclerose Múltipla , Ocludina/metabolismo , Medula Espinal/metabolismo , Molécula 1 de Adesão de Célula Vascular/metabolismo , Proteína da Zônula de Oclusão-1/metabolismo
15.
Exerc Sport Sci Rev ; 48(3): 125-132, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32412926

RESUMO

Acute intermittent hypoxia (AIH) and task-specific training (TST) synergistically improve motor function after spinal cord injury; however, mechanisms underlying this synergistic relation are unknown. We propose a hypothetical working model of neural network and cellular elements to explain AIH-TST synergy. Our goal is to forecast experiments necessary to advance our understanding and optimize the neurotherapeutic potential of AIH-TST.


Assuntos
Terapia por Exercício/métodos , Neurônios Motores/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/reabilitação , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hipocampo/metabolismo , Humanos , Hipóxia/fisiopatologia , Glicoproteínas de Membrana/metabolismo , Plasticidade Neuronal , Receptor trkB/metabolismo , Medula Espinal/metabolismo
16.
PLoS One ; 15(4): e0226050, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32240164

RESUMO

Autotaxin (ATX) is a secreted lysophospholipase D catalyzing the extracellular production of lysophosphatidic acid (LPA), a growth factor-like signaling lysophospholipid. ATX and LPA signaling have been incriminated in the pathogenesis of different chronic inflammatory diseases and various types of cancer. In this report, deregulated ATX and LPA levels were detected in the spinal cord and plasma of mice during the development of experimental autoimmune encephalomyelitis (EAE). Among the different sources of ATX expression in the inflamed spinal cord, F4/80+ CD11b+ cells, mostly activated macrophages and microglia, were found to express ATX, further suggesting an autocrine role for ATX/LPA in their activation, an EAE hallmark. Accordingly, ATX genetic deletion from CD11b+ cells attenuated the severity of EAE, thus proposing a pathogenic role for the ATX/LPA axis in neuroinflammatory disorders.


Assuntos
Encefalomielite Autoimune Experimental/genética , Lisofosfolipídeos/genética , Esclerose Múltipla/genética , Diester Fosfórico Hidrolases/genética , Animais , Antígeno CD11b/genética , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Encefalomielite Autoimune Experimental/sangue , Encefalomielite Autoimune Experimental/fisiopatologia , Deleção de Genes , Expressão Gênica/genética , Humanos , Lisofosfolipídeos/biossíntese , Macrófagos/metabolismo , Macrófagos/patologia , Camundongos , Microglia/metabolismo , Microglia/patologia , Esclerose Múltipla/sangue , Esclerose Múltipla/fisiopatologia , Transdução de Sinais/genética , Medula Espinal/metabolismo , Medula Espinal/fisiopatologia
17.
Nat Commun ; 11(1): 1773, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32286313

RESUMO

In amyotrophic lateral sclerosis (ALS), immune cells and glia contribute to motor neuron (MN) degeneration. We report the presence of NK cells in post-mortem ALS motor cortex and spinal cord tissues, and the expression of NKG2D ligands on MNs. Using a mouse model of familial-ALS, hSOD1G93A, we demonstrate NK cell accumulation in the motor cortex and spinal cord, with an early CCL2-dependent peak. NK cell depletion reduces the pace of MN degeneration, delays motor impairment and increases survival. This is confirmed in another ALS mouse model, TDP43A315T. NK cells are neurotoxic to hSOD1G93A MNs which express NKG2D ligands, while IFNγ produced by NK cells instructs microglia toward an inflammatory phenotype, and impairs FOXP3+/Treg cell infiltration in the spinal cord of hSOD1G93A mice. Together, these data suggest a role of NK cells in determining the onset and progression of MN degeneration in ALS, and in modulating Treg recruitment and microglia phenotype.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Células Matadoras Naturais/metabolismo , Neurônios Motores/metabolismo , Adulto , Idoso , Esclerose Amiotrófica Lateral/imunologia , Esclerose Amiotrófica Lateral/patologia , Animais , Modelos Animais de Doenças , Progressão da Doença , Feminino , Humanos , Células Matadoras Naturais/imunologia , Masculino , Camundongos , Pessoa de Meia-Idade , Córtex Motor/imunologia , Córtex Motor/metabolismo , Córtex Motor/patologia , Neurônios Motores/imunologia , Neurônios Motores/patologia , Receptor 1 Desencadeador da Citotoxicidade Natural/genética , Receptor 1 Desencadeador da Citotoxicidade Natural/metabolismo , Medula Espinal/imunologia , Medula Espinal/metabolismo , Medula Espinal/patologia
18.
Nat Commun ; 11(1): 1860, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32312952

RESUMO

Ependymal cells (ECs) are multiciliated neuroepithelial cells that line the ventricles of the brain and the central canal of the spinal cord (SC). How ependymal motile cilia are maintained remains largely unexplored. Here we show that zebrafish embryos deficient in Wnt signaling have defective motile cilia, yet harbor intact basal bodies. With respect to maintenance of ependymal motile cilia, plcδ3a is a target gene of Wnt signaling. Lack of Connexin43 (Cx43), especially its channel function, decreases motile cilia and intercellular Ca2+ wave (ICW) propagation. Genetic ablation of cx43 in zebrafish and mice diminished motile cilia. Finally, Cx43 is also expressed in ECs of the human SC. Taken together, our findings indicate that gap junction mediated ICWs play an important role in the maintenance of ependymal motile cilia, and suggest that the enhancement of functional gap junctions by pharmacological or genetic manipulations may be adopted to ameliorate motile ciliopathy.


Assuntos
Cílios/metabolismo , Conexina 43/metabolismo , Conexinas/metabolismo , Epêndima/metabolismo , Medula Espinal/metabolismo , Peixe-Zebra/embriologia , Animais , Diferenciação Celular , Cílios/genética , Conexina 43/genética , Epêndima/patologia , Junções Comunicantes , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Inativação de Genes , Humanos , Masculino , Camundongos , Camundongos Knockout , Transdução de Sinais/genética , Via de Sinalização Wnt/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
19.
Int. j. morphol ; 38(2): 259-264, abr. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1056432

RESUMO

The family of paired box (Pax) genes encodes the transcription factors that have been emphasized for the particular importance to embryonic development of the CNS, with the evidence obtained from various animal models. Human embryos have rarely been available for the detection of the expression of Pax family members. In this study 32 human embryos of Carnegie (CS) stages 10-20 were investigated to find the differences in the expression of Pax6 and Pax7 proteins in different regions of the neural tube and the caudal spinal cord. The expression of Pax6 and Pax7, as determined by immunohistochemistry, showed a tendency to increase in the later stages of the development both in the spinal cord and the brain. Significantly weaker expression of Pax6 and Pax7 was observed at CS 10 as compared to the later stages. At CS 10-12 weak expression of Pax6 was noticed in both dorsal and ventral parts of the developing spinal cord, while the expression of Pax7 was restricted to the cells in the roof plate and the dorsal part of the spinal cord. At CS 14-20 in the developing spinal cord Pax6 and Pax7 were detected mostly in the neuroepithelial cells of the ventricular layer, while only weak expression characterized the mantle and the marginal layers. At the same stages in the developing brain Pax6 and Pax7 were expressed in the different regions of the forebrain, the midbrain and the hindbrain suggesting for their involvement in the differentiation of neurons in specific parts of the developing brain.


La familia de genes Pax del inglés (Paired box) codifica los factores de transcripción debido a la particular importancia en el desarrollo embrionario del SNC, con la evidencia obtenida de varios modelos animales. Rara vez han estado disponibles embriones humanos para la detección de la expresión de genes de la familia Pax. En este estudio, se investigaron 32 embriones humanos de Carnegie (CS) etapas 10-20 para encontrar las diferencias en la expresión de las proteínas Pax6 y Pax7 en diferentes regiones del tubo neural y la médula espinal caudal. La expresión de Pax6 y Pax7, según la inmunohistoquímica, se observó una tendencia a aumentar en las etapas posteriores del desarrollo, tanto en la médula espinal como en el cerebro. Se observó una expresión significativamente más débil de Pax6 y Pax7 en CS 10 en comparación con las etapas posteriores. En CS 10-12 se notó una expresión débil de Pax6 en las partes dorsal y ventral de la médula espinal en desarrollo, mientras que la expresión de Pax7 se limitó a células en la placa del techo y dorsal de la médula espinal. En CS 14-20 en la médula espinal en desarrollo, Pax6 y Pax7 se observó principalmente en las células neuroepiteliales de la capa ventricular, mientras que expresión débil se caracterizó en las capas marginales. En las mismas etapas en el cerebro en desarrollo, Pax6 y Pax7 se expresaron en las diferentes áreas del prosencéfalo, el mesencéfalo y el mesencéfalo, lo que sugiere su participación en la diferenciación de las neuronas en partes específicas del cerebro en desarrollo.


Assuntos
Humanos , Medula Espinal/metabolismo , Encéfalo/crescimento & desenvolvimento , Desenvolvimento Embrionário , Fator de Transcrição PAX7/metabolismo , Fator de Transcrição PAX6/metabolismo , Medula Espinal/embriologia , Encéfalo/embriologia , Imuno-Histoquímica
20.
Am J Physiol Regul Integr Comp Physiol ; 318(6): R1058-R1067, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32348679

RESUMO

Circadian rhythms are endogenous and entrainable daily patterns of physiology and behavior. Molecular mechanisms underlie circadian rhythms, characterized by an ~24-h pattern of gene expression of core clock genes. Although it has long been known that breathing exhibits circadian rhythms, little is known concerning clock gene expression in any element of the neuromuscular system controlling breathing. Furthermore, we know little concerning gene expression necessary for specific respiratory functions, such as phrenic motor plasticity. Thus, we tested the hypotheses that transcripts for clock genes (Bmal1, Clock, Per1, and Per2) and molecules necessary for phrenic motor plasticity (Htr2a, Htr2b, Bdnf, and Ntrk2) oscillate in regions critical for phrenic/diaphragm motor function via RT-PCR. Tissues were collected from male Sprague-Dawley rats entrained to a 12-h light-dark cycle at 4 zeitgeber times (ZT; n = 8 rats/group): ZT5, ZT11, ZT17, and ZT23; ZT0 = lights on. Here, we demonstrate that 1) circadian clock genes (Bmal1, Clock, Per1, and Per2) oscillate in regions critical for phrenic/diaphragm function, including the caudal medulla, ventral C3-C5 cervical spinal cord, and diaphragm; 2) the clock protein BMAL1 is localized within CtB-labeled phrenic motor neurons; 3) genes necessary for intermittent hypoxia-induced phrenic/diaphragm motor plasticity (Htr2b and Bdnf) oscillate in the caudal medulla and ventral C3-C5 spinal cord; and 4) there is higher intensity of immunofluorescent BDNF protein within phrenic motor neurons at ZT23 compared with ZT11 (n = 11 rats/group). These results suggest local circadian clocks exist in the phrenic motor system and confirm the potential for local circadian regulation of neuroplasticity and other elements of the neural network controlling breathing.


Assuntos
Relógios Circadianos/genética , Ritmo Circadiano/fisiologia , Neurônios Motores/metabolismo , Plasticidade Neuronal/genética , Nervo Frênico/metabolismo , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição ARNTL/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Proteínas CLOCK/genética , Proteínas CLOCK/metabolismo , Expressão Gênica , Masculino , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Ratos , Ratos Sprague-Dawley , Medula Espinal/metabolismo
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