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1.
J Biol Chem ; 300(7): 107474, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38879011

RESUMO

Hearing, the ability to sense sounds, and the processing of auditory information are important for perception of the world. Mice lacking expression of neuroplastin (Np), a type-1 transmembrane glycoprotein, display deafness, multiple cognitive deficiencies, and reduced expression of plasma membrane calcium (Ca2+) ATPases (PMCAs) in cochlear hair cells and brain neurons. In this study, we transferred the deafness causing missense mutations pitch (C315S) and audio-1 (I122N) into human Np (hNp) constructs and investigated their effects at the molecular and cellular levels. Computational molecular dynamics show that loss of the disulfide bridge in hNppitch causes structural destabilization of immunoglobulin-like domain (Ig) III and that the novel asparagine in hNpaudio-1 results in steric constraints and an additional N-glycosylation site in IgII. Additional N-glycosylation of hNpaudio-1 was confirmed by PNGaseF treatment. In comparison to hNpWT, transfection of hNppitch and hNpaudio-1 into HEK293T cells resulted in normal mRNA levels but reduced the Np protein levels and their cell surface expression due to proteasomal/lysosomal degradation. Furthermore, hNppitch and hNpaudio-1 failed to promote exogenous PMCA levels in HEK293T cells. In hippocampal neurons, expression of additional hNppitch or hNpaudio-1 was less efficient than hNpWT to elevate endogenous PMCA levels and to accelerate the restoration of basal Ca2+ levels after electrically evoked Ca2+ transients. We propose that mutations leading to pathological Np variants, as exemplified here by the deafness causing Np mutants, can affect Np-dependent Ca2+ regulatory mechanisms and may potentially cause intellectual and cognitive deficits in humans.


Assuntos
Encéfalo , Cálcio , Surdez , Glicoproteínas de Membrana , Mutação de Sentido Incorreto , Neurônios , ATPases Transportadoras de Cálcio da Membrana Plasmática , Humanos , Surdez/metabolismo , Surdez/genética , Surdez/patologia , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/genética , Neurônios/metabolismo , Células HEK293 , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/genética , Cálcio/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Membrana Celular/metabolismo , Camundongos , Glicosilação
2.
Cell Calcium ; 106: 102623, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35853264

RESUMO

Upon postsynaptic glutamate receptor activation, the cytosolic Ca2+ concentration rises and initiates signaling and plasticity in spines. The plasma membrane Ca2+ ATPase (PMCA) is a major player to limit the duration of cytosolic Ca2+ signals. It forms complexes with the glycoprotein neuroplastin (Np) isoforms Np55 and Np65 and functionally interplays with N-methyl-D-aspartate (NMDA)-type ionotropic glutamate receptors (iGluNRs). Moreover, binding of the Np65-specific extracellular domain to Ca2+-permeable GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type ionotropic glutamate receptors (iGluA1Rs) was found to be required for long-term potentiation (LTP). However, the link between PMCA and iGluRs function to regulate cytosolic Ca2+ signals remained unclear. Here, we report that Np65 coordinates PMCA and iGluRs' functions to modulate the duration and amplitude of cytosolic Ca2+ transients in dendrites and spines of hippocampal neurons. Using live-cell Ca2+ imaging, acute pharmacological treatments, and GCaMP5G-expressing hippocampal neurons, we discovered that endogenous or Np65-promoted PMCA activity contributes to the restoration of basal Ca2+ levels and that this effect is dependent on iGluR activation. Super-resolution STED and confocal microscopy revealed that electrical stimulation increases the abundance of synaptic neuroplastin-PMCA complexes depending on iGluR activation and that low-rate overexpression of Np65 doubled PMCA levels and decreased cell surface levels of GluN2A and GluA1 in dendrites and Shank2-positive glutamatergic synapses. In neuroplastin-deficient hippocampi, we observed reduced PMCA and unchanged GluN2B levels, while GluN2A and GluA1 levels were imbalanced. Our electrophysiological data from hippocampal slices argues for an essential interplay of PMCA with GluN2A- but not with GluN2B-containing receptors upon induction of synaptic plasticity. Accordingly, we conclude that Np65 may interconnect PMCA with core players of glutamatergic neurotransmission to fine-tune the Ca2+ signal regulation in basal synaptic function and plasticity.


Assuntos
Adenosina Trifosfatases , Receptores Ionotrópicos de Glutamato , Adenosina Trifosfatases/metabolismo , Hipocampo/metabolismo , Plasticidade Neuronal , Neurônios/metabolismo , Receptores Ionotrópicos de Glutamato/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/metabolismo
3.
Salud colect ; 18: 4102-4102, 2022.
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1424453

RESUMO

RESUMEN Se analizan los móviles, usos y significaciones atribuidos a las placentas por mujeres y hombres en el centro-sur de Chile, a partir de la implementación de la Norma Técnica 189 del Ministerio de Salud, que permite a las personas solicitar y disponer de sus placentas con posterioridad al parto en recintos hospitalarios. A través de una mirada etnográfica acerca del tratamiento sociocultural de las placentas, entre julio y noviembre de 2019 se realizaron entrevistas en profundidad con mujeres y sus parejas; se recogieron relatos individuales, así como conversaciones con mujeres y hombres mapuches, habitantes del territorio chileno de la región de La Araucanía, la región Metropolitana y la región de Arica y Parinacota, que habían solicitado la placenta. El artículo se enfoca en cuatro casos que dan cuenta de la presencia de diversas prácticas y conocimientos en torno a la placenta, estableciendo su inscripción en marcos socioculturales, territoriales y políticos, espirituales y religiosos, según la pertenencia sociocultural de los actores. Como conclusión, se contrastan los casos relevando tanto diferencias como similitudes y se proyectan algunos desafíos derivados de los hallazgos.


ABSTRACT Motivations, uses, and meanings given to the placenta by women and men in south central Chile are analyzed, following the implementation of Technical Standard 189 by the Ministry of Health, which allowed people to request their placentas after giving birth on hospital grounds. From an ethnographic approach to the sociocultural uses of placentas, in-depth interviews were carried out with women and their partners between July and November 2019; individual narratives were recorded, as well as conversations between Mapuche women and men who had requested their placenta in three Chilean regions (Araucania, Metropolitan, and Arica and Parinacota). This article focuses on four cases that illustrate the diversity of practices and knowledge surrounding the placenta - inscribed in sociocultural, territorial, political, spiritual, and religious frameworks - according to actors' sociocultural origins. To conclude, the cases are compared in order to highlight both similarities and differences, and some challenges derived from the findings are considered.

4.
Rev. Soc. Bras. Med. Trop ; 55: e0301, 2022. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1406974

RESUMO

ABSTRACT Acinetobacter baumannii, a common pathogen in nosocomial infections, is a rare cause of community-acquired pneumonia. This report highlights the difficulties in its early diagnosis and effective treatment, as it is a multidrug-resistant microorganism with rapid, unfavorable progression. To better understand its clinical outcome, we searched the literature for similar cases but found no community-acquired cases in Brazil.

5.
Int J Mol Sci ; 22(24)2021 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-34948386

RESUMO

The recent identification of plasma membrane (Ca2+)-ATPase (PMCA)-Neuroplastin (Np) complexes has renewed attention on cell regulation of cytosolic calcium extrusion, which is of particular relevance in neurons. Here, we tested the hypothesis that PMCA-Neuroplastin complexes exist in specific ganglioside-containing rafts, which could affect calcium homeostasis. We analyzed the abundance of all four PMCA paralogs (PMCA1-4) and Neuroplastin isoforms (Np65 and Np55) in lipid rafts and bulk membrane fractions from GM2/GD2 synthase-deficient mouse brains. In these fractions, we found altered distribution of Np65/Np55 and selected PMCA isoforms, namely PMCA1 and 2. Cell surface staining and confocal microscopy identified GM1 as the main complex ganglioside co-localizing with Neuroplastin in cultured hippocampal neurons. Furthermore, blocking GM1 with a specific antibody resulted in delayed calcium restoration of electrically evoked calcium transients in the soma of hippocampal neurons. The content and composition of all ganglioside species were unchanged in Neuroplastin-deficient mouse brains. Therefore, we conclude that altered composition or disorganization of ganglioside-containing rafts results in changed regulation of calcium signals in neurons. We propose that GM1 could be a key sphingolipid for ensuring proper location of the PMCA-Neuroplastin complexes into rafts in order to participate in the regulation of neuronal calcium homeostasis.


Assuntos
Gangliosídeo G(M1)/metabolismo , Glicoproteínas de Membrana/metabolismo , Microdomínios da Membrana/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo , Animais , Encéfalo/metabolismo , Células Cultivadas , Gangliosídeo G(M1)/análise , Masculino , Glicoproteínas de Membrana/análise , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/análise
7.
Brain Struct Funct ; 226(5): 1533-1551, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33844052

RESUMO

Hearing deficits impact on the communication with the external world and severely compromise perception of the surrounding. Deafness can be caused by particular mutations in the neuroplastin (Nptn) gene, which encodes a transmembrane recognition molecule of the immunoglobulin (Ig) superfamily and plasma membrane Calcium ATPase (PMCA) accessory subunit. This study investigates whether the complete absence of neuroplastin or the loss of neuroplastin in the adult after normal development lead to hearing impairment in mice analyzed by behavioral, electrophysiological, and in vivo imaging measurements. Auditory brainstem recordings from adult neuroplastin-deficient mice (Nptn-/-) show that these mice are deaf. With age, hair cells and spiral ganglion cells degenerate in Nptn-/- mice. Adult Nptn-/- mice fail to behaviorally respond to white noise and show reduced baseline blood flow in the auditory cortex (AC) as revealed by single-photon emission computed tomography (SPECT). In adult Nptn-/- mice, tone-evoked cortical activity was not detectable within the primary auditory field (A1) of the AC, although we observed non-persistent tone-like evoked activities in electrophysiological recordings of some young Nptn-/- mice. Conditional ablation of neuroplastin in Nptnlox/loxEmx1Cre mice reveals that behavioral responses to simple tones or white noise do not require neuroplastin expression by central glutamatergic neurons. Loss of neuroplastin from hair cells in adult NptnΔlox/loxPrCreERT mice after normal development is correlated with increased hearing thresholds and only high prepulse intensities result in effective prepulse inhibition (PPI) of the startle response. Furthermore, we show that neuroplastin is required for the expression of PMCA 2 in outer hair cells. This suggests that altered Ca2+ homeostasis underlies the observed hearing impairments and leads to hair cell degeneration. Our results underline the importance of neuroplastin for the development and the maintenance of the auditory system.


Assuntos
Audição , Animais , Limiar Auditivo , Potenciais Evocados Auditivos do Tronco Encefálico , Perda Auditiva , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo
10.
Front Cell Dev Biol ; 8: 579513, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33363141

RESUMO

Correct brain wiring depends on reliable synapse formation. Nevertheless, signaling codes promoting synaptogenesis are not fully understood. Here, we report a spinogenic mechanism that operates during neuronal development and is based on the interaction of tumor necrosis factor receptor-associated factor 6 (TRAF6) with the synaptic cell adhesion molecule neuroplastin. The interaction between these proteins was predicted in silico and verified by co-immunoprecipitation in extracts from rat brain and co-transfected HEK cells. Binding assays show physical interaction between neuroplastin's C-terminus and the TRAF-C domain of TRAF6 with a K d value of 88 µM. As the two proteins co-localize in primordial dendritic protrusions, we used young cultures of rat and mouse as well as neuroplastin-deficient mouse neurons and showed with mutagenesis, knock-down, and pharmacological blockade that TRAF6 is required by neuroplastin to promote early spinogenesis during in vitro days 6-9, but not later. Time-framed TRAF6 blockade during days 6-9 reduced mEPSC amplitude, number of postsynaptic sites, synapse density and neuronal activity as neurons mature. Our data unravel a new molecular liaison that may emerge during a specific window of the neuronal development to determine excitatory synapse density in the rodent brain.

11.
Mar Drugs ; 18(6)2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32604880

RESUMO

Astaxanthin (ASX) is a carotenoid pigment with strong antioxidant properties. We have reported previously that ASX protects neurons from the noxious effects of amyloid-ß peptide oligomers, which promote excessive mitochondrial reactive oxygen species (mROS) production and induce a sustained increase in cytoplasmic Ca2+ concentration. These properties make ASX a promising therapeutic agent against pathological conditions that entail oxidative and Ca2+ dysregulation. Here, we studied whether ASX protects neurons from N-methyl-D-aspartate (NMDA)-induced excitotoxicity, a noxious process which decreases cellular viability, alters gene expression and promotes excessive mROS production. Incubation of the neuronal cell line SH-SY5Y with NMDA decreased cellular viability and increased mitochondrial superoxide production; pre-incubation with ASX prevented these effects. Additionally, incubation of SH-SY5Y cells with ASX effectively reduced the basal mROS production and prevented hydrogen peroxide-induced cell death. In primary hippocampal neurons, transfected with a genetically encoded cytoplasmic Ca2+ sensor, ASX also prevented the increase in intracellular Ca2+ concentration induced by NMDA. We suggest that, by preventing the noxious mROS and Ca2+ increases that occur under excitotoxic conditions, ASX could be useful as a therapeutic agent in neurodegenerative pathologies that involve alterations in Ca2+ homeostasis and ROS generation.


Assuntos
Cálcio/metabolismo , Mitocôndrias/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Células Cultivadas , Hipocampo/efeitos dos fármacos , Humanos , N-Metilaspartato/toxicidade , Neuroblastoma , Neurônios/efeitos dos fármacos , Cultura Primária de Células , Ratos , Xantofilas/farmacologia
12.
Br J Anaesth ; 124(1): 110-120, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31767144

RESUMO

BACKGROUND: We aimed to examine whether using a high fraction of inspired oxygen (FIO2) in the context of an individualised intra- and postoperative open-lung ventilation approach could decrease surgical site infection (SSI) in patients scheduled for abdominal surgery. METHODS: We performed a multicentre, randomised controlled clinical trial in a network of 21 university hospitals from June 6, 2017 to July 19, 2018. Patients undergoing abdominal surgery were randomly assigned to receive a high (0.80) or conventional (0.3) FIO2 during the intraoperative period and during the first 3 postoperative hours. All patients were mechanically ventilated with an open-lung strategy, which included recruitment manoeuvres and individualised positive end-expiratory pressure for the best respiratory-system compliance, and individualised continuous postoperative airway pressure for adequate peripheral oxyhaemoglobin saturation. The primary outcome was the prevalence of SSI within the first 7 postoperative days. The secondary outcomes were composites of systemic complications, length of intensive care and hospital stay, and 6-month mortality. RESULTS: We enrolled 740 subjects: 371 in the high FIO2 group and 369 in the low FIO2 group. Data from 717 subjects were available for final analysis. The rate of SSI during the first postoperative week did not differ between high (8.9%) and low (9.4%) FIO2 groups (relative risk [RR]: 0.94; 95% confidence interval [CI]: 0.59-1.50; P=0.90]). Secondary outcomes, such as atelectasis (7.7% vs 9.8%; RR: 0.77; 95% CI: 0.48-1.25; P=0.38) and myocardial ischaemia (0.6% [n=2] vs 0% [n=0]; P=0.47) did not differ between groups. CONCLUSIONS: An oxygenation strategy using high FIO2 compared with conventional FIO2 did not reduce postoperative SSIs in abdominal surgery. No differences in secondary outcomes or adverse events were found. CLINICAL TRIAL REGISTRATION: NCT02776046.


Assuntos
Oxigênio/uso terapêutico , Respiração Artificial/métodos , Infecção da Ferida Cirúrgica/prevenção & controle , Abdome/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Oxiemoglobinas/análise , Oxiemoglobinas/metabolismo , Assistência Perioperatória , Respiração com Pressão Positiva , Medicina de Precisão , Atelectasia Pulmonar/epidemiologia , Atelectasia Pulmonar/etiologia , Resultado do Tratamento
13.
Rev. Soc. Bras. Med. Trop ; 52: e20190202, 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1041534

RESUMO

Abstract INTRODUCTION: The prevalence of hepatitis C virus (HCV) infection is affected by demographic, virological, clinical, and lifestyle-related factors and varies in different regions in Brazil or worldwide. The present study aimed to clarify the epidemiological patterns of HCV infection in the interior region of Brazil. METHODS: This study was conducted in the Southern Triangle Macro-region of the state of Minas Gerais, Brazil, according to the guidelines of the National Program for the Prevention and Control of Viral Hepatitis. The participants answered a structured questionnaire on social and epidemiological factors. Immunochromatographic rapid tests were used for the qualitative detection of antibodies against HCV in whole blood (Alere HCV® Code 02FK10) in adult subjects by a free-standing method. RESULTS: Of 24,085 tested individuals, 184 (0.76%) were anti-HCV positive. The majority of anti-HCV-positive individuals were born between 1951 and 1980 (n=146 [79.3%]), with 68 women and 116 men. Identified risk factors included syringe and/or needle sharing (p = 0.003), being in prison (p = 0.004), and having tattoos or piercings (p = 0.005) and were significantly associated with the decade of birth. CONCLUSIONS: The study shows the importance of testing populations at risk for HCV infection, including incarcerated individuals, those with tattoos or piercings, those who share or have shared syringes or needles, and those in high-risk birth cohorts (1950s, 1960s, and 1970s) in the Southern Triangle Macro-region.


Assuntos
Humanos , Masculino , Feminino , Adulto , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Hepatite C/epidemiologia , Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/sangue , Brasil/epidemiologia , Prevalência , Estudos Transversais , Fatores de Risco , Hepatite C/diagnóstico , Monitoramento Epidemiológico , Pessoa de Meia-Idade
14.
Biochem Biophys Res Commun ; 505(1): 201-207, 2018 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-30243728

RESUMO

The neurotrophin Brain-Derived Neurotrophic Factor (BDNF) induces complex neuronal signaling cascades that are critical for the cellular changes underlying synaptic plasticity. These pathways include activation of Ca2+ entry via N-methyl-D-aspartate receptors and sequential activation of nitric oxide synthase and NADPH oxidase, which via generation of reactive nitrogen/oxygen species stimulate Ca2+-induced Ca2+ release mediated by Ryanodine Receptor (RyR) channels. These sequential events underlie BDNF-induced spine remodeling and type-2 RyR up-regulation. In addition, BDNF induces the nuclear translocation of the transcription factor Nrf2, a master regulator of antioxidant protein expression that protects cells against the oxidative damage caused by injury and inflammation. To investigate the possible BDNF-induced signaling cascades that mediate Nrf2 nuclear translocation in primary hippocampal cultures, we tested here whether reactive oxygen species, RyR-mediated Ca2+ release, ERK or PI3K contribute to this response. We found that pre-incubation of cultures with inhibitory ryanodine to suppress RyR-mediated Ca2+ release, with the reducing agent N-acetylcysteine or with inhibitors of ERK or PI3K activity, prevented the nuclear translocation of Nrf2 induced by incubation for 6 h with BFNF. Based on these combined results, we propose that the key role played by BDNF as an inducer of neuronal antioxidant responses, characterized by BDNF-induced Nfr2 nuclear translocation, entails crosstalk between reactive oxygen species and RyR-mediated Ca2+ release, and the participation of ERK and PI3K activities.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Acetilcisteína/farmacologia , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Animais , Sinalização do Cálcio/efeitos dos fármacos , Células Cultivadas , Sequestradores de Radicais Livres/farmacologia , Hipocampo/citologia , Hipocampo/embriologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos
15.
J Neuroinflammation ; 15(1): 216, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30068357

RESUMO

BACKGROUND: Chronic infection with the neurotropic parasite Toxoplasma gondii has been implicated in the risk for several neuropsychiatric disorders. The mechanisms, by which the parasite may alter neural function and behavior of the host, are not yet understood completely. METHODS: Here, a novel proteomic approach using mass spectrometry was employed to investigate the alterations in synaptic protein composition in a murine model of chronic toxoplasmosis. In a candidate-based strategy, immunoblot analysis and immunohistochemistry were applied to investigate the expression levels of key synaptic proteins in glutamatergic signaling. RESULTS: A comparison of the synaptosomal protein composition revealed distinct changes upon infection, with multiple proteins such as EAAT2, Shank3, AMPA receptor, and NMDA receptor subunits being downregulated, whereas inflammation-related proteins showed an upregulation. Treatment with the antiparasitic agent sulfadiazine strongly reduced tachyzoite levels and diminished neuroinflammatory mediators. However, in both conditions, a significant number of latent cysts persisted in the brain. Conversely, infection-related alterations of key synaptic protein levels could be partly reversed by the treatment. CONCLUSION: These results provide evidence for profound changes especially in synaptic protein composition in T. gondii-infected mice with a downregulation of pivotal components of glutamatergic neurotransmission. Our results suggest that the detected synaptic alterations are a consequence of the distinct neuroinflammatory milieu caused by the neurotropic parasite.


Assuntos
Encéfalo/metabolismo , Regulação da Expressão Gênica/fisiologia , Sinapses/metabolismo , Sinaptossomos/metabolismo , Toxoplasmose Animal/patologia , Animais , Antiprotozoários/farmacologia , Doença Crônica , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Espectrometria de Massas , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Metanálise como Assunto , Camundongos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Proteômica , RNA Mensageiro/metabolismo , Sulfadiazina/farmacologia , Sinapses/patologia , Sinaptossomos/efeitos dos fármacos , Espectrometria de Massas em Tandem , Toxoplasma/patogenicidade
16.
Int J Mol Sci ; 19(8)2018 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-30049932

RESUMO

Under pro-inflammatory conditions, astrocytes become reactive and acquire a migratory phenotype. Our results show that hemichannels formed by connexin 43 (Cx43) play an important role in Thy-1-induced astrocyte migration. The neuronal protein Thy-1 binds to αvß3 integrin in astrocytes, thereby leading to intricate signaling pathways that include calcium (Ca2+) release from intracellular stores, opening of Cx43 hemichannels, release of ATP, activation of P2X7 receptor, and Ca2+ influx. However, because these Thy-1 effects occur exclusively in reactive astrocytes, we wondered whether by elevating calcium levels and promoting hemichannel opening we could prompt non-reactive astrocytes to respond to Thy-1. Cx43 immunoreactivity increased at juxta-membrane sites, where hemichannels (not gap junctions) participate in astrocyte polarization and migration stimulated by Thy-1. Also, intracellular Ca2+ increase, due to ionomycin treatment, induced hemichannel opening, but activated astrocyte migration only partially, and this limitation was overcome by pre-treatment with tumor necrosis factor (TNF) and Thy-1. Finally, αvß3 integrin formed membrane clusters after TNF stimulation or overexpression of ß3 integrin. We suggest that these microclusters are required for cells to respond to Thy-1 stimulation. Therefore, the large increase in intracellular Ca2+ and hemichannel opening induced by ionomycin are required, but not sufficient, to permit Thy-1-induced astrocyte migration. Thus, we suggest that proinflammatory stimuli prompt astrocytes to respond to migratory signals of neuronal cells.


Assuntos
Astrócitos/citologia , Cálcio/metabolismo , Movimento Celular , Conexina 43/metabolismo , Antígenos Thy-1/metabolismo , Animais , Astrócitos/metabolismo , Sinalização do Cálcio , Linhagem Celular , Polaridade Celular , Células Cultivadas , Ratos , Ratos Wistar
17.
J Neuroinflammation ; 14(1): 194, 2017 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-28962574

RESUMO

BACKGROUND: Neuroinflammation involves cytokine release, astrocyte reactivity and migration. Neuronal Thy-1 promotes DITNC1 astrocyte migration by engaging αVß3 Integrin and Syndecan-4. Primary astrocytes express low levels of these receptors and are unresponsive to Thy-1; thus, inflammation and astrocyte reactivity might be necessary for Thy-1-induced responses. METHODS: Wild-type rat astrocytes (TNF-activated) or from human SOD1G93A transgenic mice (a neurodegenerative disease model) were used to evaluate cell migration, Thy-1 receptor levels, signaling molecules, and reactivity markers. RESULTS: Thy-1 induced astrocyte migration only after TNF priming. Increased expression of αVß3 Integrin, Syndecan-4, P2X7R, Pannexin-1, Connexin-43, GFAP, and iNOS were observed in TNF-treated astrocytes. Silencing of ß3 Integrin prior to TNF treatment prevented Thy-1-induced migration, while ß3 Integrin over-expression was sufficient to induce astrocyte reactivity and allow Thy-1-induced migration. Finally, hSOD1G93A astrocytes behave as TNF-treated astrocytes since they were reactive and responsive to Thy-1. CONCLUSIONS: Therefore, inflammation induces expression of αVß3 Integrin and other proteins, astrocyte reactivity, and Thy-1 responsiveness. Importantly, ectopic control of ß3 Integrin levels modulates these responses regardless of inflammation.


Assuntos
Astrócitos/fisiologia , Movimento Celular/fisiologia , Regulação da Expressão Gênica/genética , Integrina alfaVbeta3/metabolismo , Animais , Animais Geneticamente Modificados , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Células Cultivadas , Conexinas/genética , Conexinas/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Integrina alfaVbeta3/genética , Camundongos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Ratos , Receptores Purinérgicos P2/genética , Receptores Purinérgicos P2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Antígenos Thy-1/farmacologia , Fator de Necrose Tumoral alfa/farmacologia , Cicatrização/fisiologia
18.
Sci Rep ; 7(1): 8358, 2017 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-28827723

RESUMO

The outcome of T cell activation is determined by mechanisms that balance Ca2+ influx and clearance. Here we report that murine CD4 T cells lacking Neuroplastin (Nptn -/-), an immunoglobulin superfamily protein, display elevated cytosolic Ca2+ and impaired post-stimulation Ca2+ clearance, along with increased nuclear levels of NFAT transcription factor and enhanced T cell receptor-induced cytokine production. On the molecular level, we identified plasma membrane Ca2+ ATPases (PMCAs) as the main interaction partners of Neuroplastin. PMCA levels were reduced by over 70% in Nptn -/- T cells, suggesting an explanation for altered Ca2+ handling. Supporting this, Ca2+ extrusion was impaired while Ca2+ levels in internal stores were increased. T cells heterozygous for PMCA1 mimicked the phenotype of Nptn -/- T cells. Consistent with sustained Ca2+ levels, differentiation of Nptn -/- T helper cells was biased towards the Th1 versus Th2 subset. Our study thus establishes Neuroplastin-PMCA modules as important regulators of T cell activation.


Assuntos
Cálcio/metabolismo , Membrana Celular/metabolismo , Glicoproteínas de Membrana/fisiologia , ATPases Transportadoras de Cálcio da Membrana Plasmática/fisiologia , Linfócitos T/fisiologia , Animais , Sinalização do Cálcio , Diferenciação Celular , Núcleo Celular , Regulação da Expressão Gênica , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Linfócitos T/imunologia
19.
Rev. chil. dermatol ; 33(1): 33-36, 2017. ilus
Artigo em Espanhol | LILACS | ID: biblio-964627

RESUMO

Se presenta el caso de una mujer de 77 años, sin antecedentes relevantes, con úlcera en tobillo izquierdo de dos años de evolución relacionada a herida previa por quemadura con agua caliente de aproximadamente 60 años de antigüedad, con crecimiento progresivo y mala respuesta a tratamiento inicial con curaciones y luego con antibióticos. Se realiza estudio con biopsia cutánea incisional que confirma cáncer espinocelular moderadamente diferenciado e infiltrante en dermis reticular, lo cual corresponde a una úlcera de Marjolin. Se deriva a cirugía oncológica en donde se realiza el estudio de etapificación con resultado de lesión ósea por contigüidad y una tomografía computada (TC) de tórax, abdomen y pelvis sin diseminación a distancia, por lo que se decide amputación infracondilea de la extremidad afectada. Debido a este caso de interés, se realiza una revisión sobre úlcera de Marjolin, con el fin de lograr un diagnóstico adecuado y un tratamiento precoz.


We present the case of a 77-year-old woman, with no relevant history, with a left ankle ulcer of two years of evolution related to previous burn injury with hot water of approximately 60 years old, with progressive growth and poor response to initial treatment with cures and then with antibiotics. A study was performed with cutaneous incisional biopsy confirming moderately differentiated and infiltrating squamous cell cancer in the reticular dermis, which corresponds to a Marjolin ulcer. It is derived to oncologic surgery where the etapification study is carried out with result of contiguous bone injury and a computed tomography (CT) thorax, abdomen and pelvis without distant dissemination, so infracondile amputation of the affected extremity is decided. Due to this interest case report, a review of Marjolin's ulcer is performed, in order to achieve an adequate diagnosis and early treatment.


Assuntos
Humanos , Feminino , Idoso , Neoplasias Cutâneas/diagnóstico , Carcinoma de Células Escamosas/diagnóstico , Neoplasias Cutâneas/patologia , Úlcera Cutânea/etiologia , Biópsia , Carcinoma de Células Escamosas/patologia ,
20.
GED gastroenterol. endosc. dig ; 35(1): 28-31, jan.-mar. 2016.
Artigo em Português | LILACS | ID: lil-784379

RESUMO

A hepatopatia crônica causada pelo vírus da hepatite C (HCV) é a indicação mais comum de transplante hepático no mundo. A recorrência da hepatite C após o transplante hepático é elevada e em grande parte dos pacientes pode evoluir com cirrose e perda do enxerto de forma acelerada. Relatamos caso de portadora de cirrose por hepatite C genótipo 1a, tratada durante sete semanas com Interferon Peguilado e Ribavirina, em Resposta Viral Sustentada (RVS), mesmo após transplante hepático por hepatocarcinoma.


Chronic liver disease caused by hepatitis C virus (HCV) is the most common indication for liver transplantation in the world. The recurrence of hepatitis C after liver transplantation is high and most patients can develop cirrhosis and graft loss in an accelerated manner. A case of a patient with cirrhosis due to hepatitis C genotype 1a, treated for seven weeks with pegylated interferon and Ribavirin in Sustained Viral Response (SVR), even after liver transplantation for hepatocellular carcinoma.


Assuntos
Humanos , Feminino , Idoso , Ribavirina , Transplante de Fígado , Interferon-alfa , Carcinoma Hepatocelular , Hepatite C Crônica , Resposta Viral Sustentada , Cirrose Hepática
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