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1.
Cureus ; 12(7): e9241, 2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32821587

RESUMO

A 64-year-old female presented to the ED with severe abdominal pain. Initially it was suspected to be spontaneous aortic rupture or dissection. Contrasted CT imaging studies did not identify aneurysm and dissection, but did identify a concerning, confounding, and curious collection of fluid in the upper right quadrant. Angiography imaging was obtained and identified the origin as the collecting duct of the right kidney. The patient was admitted to the medical service. She was then evaluated by the urology service and they identified this presentation as a urinoma with extravasation of urine, in the absence of trauma or identifiable obstruction.

2.
Clin Transl Allergy ; 10: 10, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32337019

RESUMO

BACKGROUND: Pollen and house dust mite (HDM) subcutaneous immunotherapy (SLIT) and pollen subcutaneous immunotherapy (SCIT) are effective therapies for children with allergic rhinoconjunctivitis (AR). There are no previous direct comparative studies investigating quality of life (QoL) of all three immunotherapy regimes. The aim of this study was to compare QoL and safety in children receiving these immunotherapies for AR. METHODS: Demographic characteristics, Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and Visual Analogue (VAS) scores were assessed in 249 children undergoing HDM and pollen immunotherapy at a UK specialist paediatric centre between 2007 and 2019. RESULTS: All three immunotherapy regimes led to a > 50% improvement in QoL and VAS after 3 years of therapy, with significant improvements by the end of the first year (p < 0.05) and further improvements between 1 and 3 years (p < 0.05). Age, gender, ethnicity and route of administration had no significant bearing on efficacy. Older, polysensitised children and those receiving HDM SLIT were all more likely to discontinue their treatment (all with p < 0.05). The only patient to suffer from anaphylaxis requiring intramuscular adrenaline, and 80% experiencing exacerbations of their asthma had received pollen SCIT. CONCLUSIONS: Pollen SCIT and pollen and HDM SLIT all lead to significant improvements in QoL. The risk of anaphylaxis is low, but SCIT is associates with a 1 in 5 chance of asthma flares in the days after its administration. Discontinuation of therapy is more frequent in older, polysensitised children, and those undergoing HDM immunotherapy.

3.
Phys Rev Lett ; 112(9): 097201, 2014 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-24655273

RESUMO

We consider an n-component fixed-length order parameter interacting with a weak random field in d=1, 2, 3 dimensions. Relaxation from the initially ordered state and spin-spin correlation functions are studied on lattices containing hundreds of millions of sites. At n ≤ d the presence of topological defects leads to strong metastability and glassy behavior, with the final state depending on the initial condition. At n=d+1, when topological structures are nonsingular, the system possesses a weak metastability. At n>d+1, when topological objects are absent, the final, lowest-energy state is independent of the initial condition. It is characterized by the exponential decay of correlations that agrees quantitatively with the theory based upon the Imry-Ma argument.

4.
Nanomaterials (Basel) ; 2(3): 275-285, 2012 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-28348308

RESUMO

In the present work, the procedures for the creation of self-assembled DNA nanostructures in aqueous and non-aqueous media are described. DNA-Surfactant complex formation renders the DNA soluble in organic solvents offering an exciting way to bridge the transition of DNA origami materials electronics applications. The DNA retains its structural features, and these unique geometries provide an interesting candidate for future electronics and nanofabrication applications with potential for new properties. The DNA architectures were first assembled under aqueous conditions, and then characterized in solution (using circular dichroism (CD) spectroscopy) and on the surface (using atomic force microscopy (AFM)). Following aqueous assembly, the DNA nanostructures were transitioned to a non-aqueous environment, where butanol was chosen for optical compatibility and thermal properties. The retention of DNA hierarchical structure and thermal stability in non-aqueous conditions were confirmed via CD spectroscopy. The formation and characterization of these higher order DNA-surfactant complexes is described in this paper.

5.
J Res Natl Inst Stand Technol ; 116(6): 821-6, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-26989602

RESUMO

The National Institute of Standards and Technology (NIST) Conical Reference Transducer (CRT) is designed for purposes requiring frequency response characteristics much more uniform than those attainable with ultrasonic transducers conventionally used for acoustic emission (AE) nondestructive testing. The high performance of the CRT results from the use of design elements radically different from those of conventional transducers. The CRT was offered for sale for 15 years (1985 to 2000). Each CRT was furnished with data which expressed, as a function of frequency, the transducer sensitivity in volts per micrometer of normal displacement on the test block. Of the 22 transducers constructed, eight were reserved for long term research and were stored undisturbed in a laboratory with well controlled temperature and humidity. In 2009, the sensitivities of these eight units were redetermined. The 2009 data have been compared with data from similar tests conducted in 1985. The results of this comparison verify the claim "Results of tests of the long term stability of CRT characteristics indicate that, if proper care is taken, tens of years of service can reasonably be expected." made in the CRT specifications document furnished to prospective customers.

6.
J Neuroimmunol ; 225(1-2): 52-61, 2010 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-20546940

RESUMO

Recombinant T cell ligands (RTLs) ameliorate experimental autoimmune encephalomyelitis (EAE) in an antigen-specific manner. We evaluated effects of RTL401 (I-A(s) alpha1beta1+PLP-139-151) on splenocytes from SJL/J mice with EAE to study RTL-T cell tolerance-inducing mechanisms. RTLs bound to B, macrophages and DCs, through RTL-MHC-alpha1beta1 moiety. RTL binding reduced CD11b expression on splenic macrophages/DC, and RTL401-conditioned macrophages/DC, not B cells, inhibited T cell activation. Reduced ability of RTL- incubated splenocytes to transfer EAE was likely mediated through macrophages/DC, since B cells were unnecessary for RTL treatment of EAE. These results demonstrate a novel pathway of T cell regulation by RTL-bound APCs.


Assuntos
Células Apresentadoras de Antígenos/metabolismo , Antígeno CD11b/metabolismo , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/terapia , Regulação da Expressão Gênica/efeitos dos fármacos , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas Recombinantes/metabolismo , Sequência de Aminoácidos , Animais , Células Apresentadoras de Antígenos/efeitos dos fármacos , Células Apresentadoras de Antígenos/imunologia , Células Cultivadas , Técnicas de Cocultura , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Citometria de Fluxo , Regulação da Expressão Gênica/imunologia , Ligantes , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Proteína Proteolipídica de Mielina/imunologia , Fragmentos de Peptídeos/imunologia , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Receptores de Antígenos de Linfócitos T/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/uso terapêutico , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo
7.
Mol Imaging Biol ; 12(3): 240-9, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19949987

RESUMO

PURPOSE: The purpose of this study is to detect myelin-specific T cells, key pathological mediators in early multiple sclerosis, and the corresponding animal model, experimental autoimmune encephalomyelitis (EAE), in the mouse spinal cord. PROCEDURES: T cells were labeled with the iron-based, magnetic resonance (MR) contrast reagent, Feridex, and the transfection reagent, protamine sulfate, resulting in approximately 100% iron-labeling efficiency. Feridex-labeling did not alter the induction of EAE by T cells, and recipients were imaged by a 12-T MR instrument. RESULTS: Focal hypointense lesions were resolvable to gray or white matter of the lumbar spinal cord in T(2)-weighted images of the recipients of Feridex-labeled T cells. Lesions corresponded to histological evidence of inflammatory lesions and iron-labeled cells in eight-of-eight mice. In contrast, hypointense lesions were not observed eight-of-eight recipients of unlabeled T cells. CONCLUSIONS: These results demonstrate and provide methodologies for labeling, detecting, and extracting MRI-detectable foci of iron-labeled cells.


Assuntos
Autoimunidade/imunologia , Encefalomielite Autoimune Experimental/imunologia , Inflamação/imunologia , Imageamento por Ressonância Magnética , Bainha de Mielina/imunologia , Medula Espinal/imunologia , Linfócitos T/imunologia , Animais , Encefalomielite Autoimune Experimental/patologia , Inflamação/diagnóstico , Ferro/metabolismo , Camundongos , Bainha de Mielina/patologia , Protaminas/metabolismo , Medula Espinal/patologia , Coloração e Rotulagem
8.
J Neurosci Res ; 88(1): 7-15, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19642196

RESUMO

The regulatory role of programmed death 1 (PD-1) was investigated in the development of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Typical EAE could be induced by immunization without pertussis toxin (PTX) in PD-1-null but not in wild-type (WT) mice. However, both strains developed a similar EAE phenotype when immunized with PTX or by adoptive transfer of pathogenic T cells. In WT mice that did not develop EAE after immunization without PTX, the frequency of CD4(+)FoxP3(+) Treg cells was boosted in the periphery but not in the thymus. This increase in Treg frequency was abrogated by PD-1 deficiency or inclusion of PTX. In addition, PD-1 expression was critical to in vitro conversion of naïve myelin-specific CD4 T cells into Treg cells and was directly related to Treg suppressive activity. Finally, PD-1 was markedly down-modulated in the periphery of WT mice after administration of PTX. Therefore, down-modulation of PD-1 in Treg cells may abrogate Treg-mediated immune suppression, permitting the activation of myelin-reactive T cells and induction of EAE.


Assuntos
Antígenos de Superfície/genética , Proteínas Reguladoras de Apoptose/genética , Encefalomielite Autoimune Experimental/genética , Linfócitos T Reguladores/imunologia , Animais , Antígenos de Superfície/imunologia , Proteínas Reguladoras de Apoptose/imunologia , Linfócitos T CD4-Positivos/imunologia , Proliferação de Células , Regulação para Baixo , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/patologia , Feminino , Citometria de Fluxo , Adjuvante de Freund/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Knockout , Toxina Pertussis/imunologia , Receptor de Morte Celular Programada 1 , Medula Espinal/patologia , Coloração e Rotulagem
9.
J Neurosci ; 29(12): 3816-23, 2009 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-19321778

RESUMO

Recombinant T-cell receptor ligands (RTLs) can reverse clinical and histological signs of experimental autoimmune encephalomyelitis (EAE) in an antigen-specific manner, and are currently in clinical trials for treatment of subjects with multiple sclerosis (MS). Antigen specificity of RTL raises the question as to whether this treatment would be successful in MS patients where target antigens are unknown. Using spinal cord homogenate or combinations of two different peptides to induce disease, we found that treatment with single RTL could reverse EAE as long as targeted T-cells were present. Therapy with three different RTLs each caused a significant reduction in IL-17 and increases in IL-10 and IL-13 in peptide-activated splenocytes, reduced proliferation of both cognate and bystander specificities of lymph node cells, and reduced inflammatory lesions and secreted IL-17 and IL-2 from peptide-activated spinal cord cells. These results show that treatment with single RTLs can induce a cytokine switch in cognate T-cells that inhibits both the target and bystander T-cells, providing new evidence for the potential applicability of RTL therapy in MS.


Assuntos
Citocinas/metabolismo , Encefalomielite Autoimune Experimental/tratamento farmacológico , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas Recombinantes de Fusão/uso terapêutico , Especificidade do Receptor de Antígeno de Linfócitos T , Animais , Efeito Espectador , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Feminino , Ligantes , Camundongos , Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Medula Espinal/imunologia , Medula Espinal/patologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/patologia , Extratos de Tecidos/imunologia
10.
J Immunol ; 182(5): 3294-303, 2009 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-19234228

RESUMO

Although estrogens exert a pronounced protective effect on multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), their therapeutic application has been limited by undesirable side effects thought to be mediated primarily through estradiol binding to intracellular estrogen receptor alpha. In this study, we found that signaling through the putative membrane estrogen receptor, G protein-coupled receptor 30 (GPR30), was sufficient to mediate protection against EAE, which was significantly impaired in GPR30 gene-deficient mice. Treatment with G-1, an agonist that selectively activates GPR30 without engagement of the intracellular estrogen receptors, retained the ability of estradiol to protect against clinical and histological EAE without estradiol-associated side effects, deviated cytokine profiles, and enhanced suppressive activity of CD4(+)Foxp3(+) T regulatory cells through a GPR30- and programmed death 1-dependent mechanism. This study is the first to evaluate the protective effect of GPR30 activation on EAE, and provides a strong foundation for the clinical application of GPR30 agonists such as G-1 in multiple sclerosis.


Assuntos
Antígenos de Superfície/biossíntese , Proteínas Reguladoras de Apoptose/biossíntese , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/prevenção & controle , Proteínas de Membrana/fisiologia , Receptores de Estrogênio/fisiologia , Receptores Acoplados a Proteínas G/fisiologia , Regulação para Cima/imunologia , Sequência de Aminoácidos , Animais , Antígenos de Superfície/fisiologia , Proteínas Reguladoras de Apoptose/deficiência , Proteínas Reguladoras de Apoptose/fisiologia , Células Cultivadas , Ciclopentanos/farmacologia , Encefalomielite Autoimune Experimental/metabolismo , Estradiol/fisiologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dados de Sequência Molecular , Receptor de Morte Celular Programada 1 , Quinolinas/farmacologia , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/deficiência , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Regulação para Cima/genética
11.
Neurobiol Dis ; 33(2): 274-81, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19049874

RESUMO

The accumulation of amyloid-beta (Abeta) into plaques is a hallmark feature of Alzheimer's disease (AD). While amyloid precursor protein (APP)-related proteins are found in most organisms, only Abeta fragments from human APP have been shown to induce amyloid deposits and progressive neurodegeneration. Therefore, it was suggested that neurotoxic effects are a specific property of human Abeta. Here we show that Abeta fragments derived from the Drosophila orthologue APPL aggregate into intracellular fibrils, amyloid deposits, and cause age-dependent behavioral deficits and neurodegeneration. We also show that APPL can be cleaved by a novel fly beta-secretase-like enzyme. This suggests that Abeta-induced neurotoxicity is a conserved function of APP proteins whereby the lack of conservation in the primary sequence indicates that secondary structural aspects determine their pathogenesis. In addition, we found that the behavioral phenotypes precede extracellular amyloid deposit formation, supporting results that intracellular Abeta plays a key role in AD.


Assuntos
Amiloide/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Envelhecimento , Sequência de Aminoácidos , Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animais , Apoptose/fisiologia , Comportamento Animal , Western Blotting , Encéfalo/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/citologia , Drosophila melanogaster/genética , Expressão Gênica , Imuno-Histoquímica , Luz , Proteínas de Membrana/genética , Microscopia Eletrônica , Dados de Sequência Molecular , Degeneração Neural , Proteínas do Tecido Nervoso/genética , Fragmentos de Peptídeos/metabolismo , Nexinas de Proteases , Receptores de Superfície Celular/genética
12.
J Immunol ; 180(4): 2679-85, 2008 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18250480

RESUMO

Females tend to have stronger Th1-mediated immune responses and are more prone to develop autoimmune diseases, including multiple sclerosis. Macrophages are major effector cells capable of mediating or modulating immune responses in experimental autoimmune encephalomyelitis (EAE). IL-13 and estrogen have opposing roles on macrophages (the former enhancing and the latter inhibiting) in terms of MHC class II (MHC II) up-regulation and, thus, these factors might influence susceptibility to EAE differently in females vs males. In accordance with this hypothesis, females lacking IL-13 displayed lower incidence and milder EAE disease severity than males after immunization with myelin oligodendrocyte glycoprotein (MOG)-35-55 peptide/CFA/pertussis toxin. Female IL-13 knockout (KO) mice with EAE consistently had reduced infiltration of CD11b(+) macrophages in the CNS along with significantly reduced expression of MHC II on these cells. Impaired MHC II expression was further corroborated upon LPS stimulation of female but not male bone marrow-derived CD11b(+) macrophages from IL-13KO mice, with restored expression after IL-13 pretreatment of female but not male macrophages. APCs from IL-13KO females induced less proliferation by MOG-35-55-reactive T cells, and splenocytes from MOG peptide-immunized females had lower expression of IL-12, IFN-gamma, MIP-2, and IFN-gamma-inducible protein 10 than males. In contrast, these splenocytes had higher expression of anti-inflammatory factors, IL-10, TGF-beta1, and FoxP3, a cytokine pattern typical of regulatory type II monocytes. These data suggest that the difference in EAE susceptibility in females is strongly influenced by gender-specific proinflammatory effects of IL-13, mediated in part through up-regulation of Th1-inducing cytokines and MHC II on CD11b(+) macrophages.


Assuntos
Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Predisposição Genética para Doença , Interleucina-13/fisiologia , Caracteres Sexuais , Animais , Apresentação de Antígeno/genética , Apresentação de Antígeno/imunologia , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Linhagem Celular , Células Cultivadas , Encefalomielite Autoimune Experimental/epidemiologia , Feminino , Incidência , Interleucina-13/deficiência , Interleucina-13/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
13.
J Neurosci ; 27(46): 12531-9, 2007 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-18003831

RESUMO

Recombinant T-cell receptor ligands (RTLs) can prevent and reverse clinical and histological signs of experimental autoimmune encephalomyelitis (EAE) in an antigen-specific manner and are currently in clinical trials for treatment of subjects with multiple sclerosis (MS). To evaluate regulatory mechanisms, we designed and tested RTL551, containing the alpha1 and beta1 domains of the I-A(b) class II molecule covalently linked to the encephalitogenic MOG-35-55 peptide in C57BL/6 mice. Treatment of active or passive EAE with RTL551 after disease onset significantly reduced clinical signs and spinal cord lesions. Moreover, RTL551 treatment strongly and selectively reduced secretion of interleukin-17 and tumor necrosis factor alpha by transferred green fluorescent protein-positive (GFP+) MOG-35-55-reactive T-cells and almost completely abrogated existent GFP+ cellular infiltrates in affected spinal cord sections. Reduced inflammation in spinal cords of RTL551-treated mice was accompanied by a highly significant downregulation of chemokines and their receptors and inhibition of VCAM-1 (vascular cell adhesion molecule-1) and ICAM-1 (intercellular adhesion molecule-1) expression by endothelial cells. Thus, RTL therapy cannot only inhibit systemic production of encephalitogenic cytokines by the targeted myelin oligodendrocyte glycoprotein-reactive T-cells but also impedes downstream local recruitment and retention of inflammatory cells in the CNS. These findings indicate that targeted immunotherapy of antigen-specific T-cells can result in a reversal of CNS lesion formation and lend strong support to the application of the RTL approach for therapy in MS.


Assuntos
Movimento Celular/efeitos dos fármacos , Encefalomielite Autoimune Experimental/tratamento farmacológico , Fatores Imunológicos/farmacologia , Interleucina-17/metabolismo , Receptores de Antígenos de Linfócitos T/efeitos dos fármacos , Proteínas Recombinantes de Fusão/farmacologia , Animais , Moléculas de Adesão Celular/efeitos dos fármacos , Moléculas de Adesão Celular/imunologia , Movimento Celular/imunologia , Quimiocinas/efeitos dos fármacos , Quimiocinas/imunologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/imunologia , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/fisiopatologia , Proteínas de Fluorescência Verde , Fatores Imunológicos/uso terapêutico , Imunoterapia/métodos , Interleucina-17/imunologia , Ligantes , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/imunologia , Esclerose Múltipla/fisiopatologia , Fragmentos de Peptídeos/farmacologia , Fragmentos de Peptídeos/uso terapêutico , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas Recombinantes de Fusão/uso terapêutico , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Resultado do Tratamento , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/imunologia
14.
J Comp Neurol ; 502(2): 175-91, 2007 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-17348007

RESUMO

Eph receptor tyrosine kinases and their ephrin ligands participate in the control of neuronal growth and migration in a variety of contexts, but the mechanisms by which they guide neuronal motility are still incompletely understood. By using the enteric nervous system (ENS) of the tobacco hornworm Manduca sexta as a model system, we have explored whether Manduca ephrin (MsEphrin; a GPI-linked ligand) and its Eph receptor (MsEph) might regulate the migration and outgrowth of enteric neurons. During formation of the Manduca ENS, an identified set of approximately 300 neurons (EP cells) populates the enteric plexus of the midgut by migrating along a specific set of muscle bands forming on the gut, but the neurons strictly avoid adjacent interband regions. By determining the mRNA and protein expression patterns for MsEphrin and the MsEph receptor and by examining their endogenous binding patterns within the ENS, we have demonstrated that the ligand and its receptor are distributed in a complementary manner: MsEphrin is expressed exclusively by the migratory EP cells, whereas the MsEph receptor is expressed by midline interband cells that are normally inhibitory to migration. Notably, MsEphrin could be detected on the filopodial processes of the EP cells that extended up to but not across the midline cells expressing the MsEph receptor. These results suggest a model whereby MsEphrin-dependent signaling regulates the response of migrating neurons to a midline inhibitory boundary, defined by the expression of MsEph receptors in the developing ENS.


Assuntos
Movimento Celular/fisiologia , Sistema Nervoso Entérico/citologia , Efrinas/metabolismo , Expressão Gênica/fisiologia , Manduca/anatomia & histologia , Neurônios/fisiologia , Receptor EphA1/metabolismo , Animais , Evolução Biológica , Embrião não Mamífero , Microscopia Eletrônica/métodos , Neurônios/ultraestrutura , RNA Mensageiro/metabolismo , Receptor EphA1/genética
15.
J Cell Biol ; 168(4): 655-66, 2005 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-15699217

RESUMO

Schwann cells form basal laminae (BLs) containing laminin-2 (Ln-2; heterotrimer alpha2beta1gamma1) and Ln-8 (alpha4beta1gamma1). Loss of Ln-2 in humans and mice carrying alpha2-chain mutations prevents developing Schwann cells from fully defasciculating axons, resulting in partial amyelination. The principal pathogenic mechanism is thought to derive from structural defects in Schwann cell BLs, which Ln-2 scaffolds. However, we found loss of Ln-8 caused partial amyelination in mice without affecting BL structure or Ln-2 levels. Combined Ln-2/Ln-8 deficiency caused nearly complete amyelination, revealing Ln-2 and -8 together have a dominant role in defasciculation, and that Ln-8 promotes myelination without BLs. Transgenic Ln-10 (alpha5beta1gamma1) expression also promoted myelination without BL formation. Rather than BL structure, we found Ln-2 and -8 were specifically required for the increased perinatal Schwann cell proliferation that attends myelination. Purified Ln-2 and -8 directly enhanced in vitro Schwann cell proliferation in collaboration with autocrine factors, suggesting Lns control the onset of myelination by modulating responses to mitogens in vivo.


Assuntos
Axônios/metabolismo , Membrana Basal/metabolismo , Laminina/metabolismo , Bainha de Mielina/metabolismo , Células de Schwann/metabolismo , Animais , Axônios/patologia , Membrana Basal/patologia , Comportamento Animal , Adesão Celular/fisiologia , Proliferação de Células , Células Cultivadas , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Humanos , Laminina/genética , Camundongos , Camundongos Transgênicos , Bainha de Mielina/patologia , Ratos , Células de Schwann/patologia
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