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1.
Am J Case Rep ; 25: e942475, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38303503

RESUMO

BACKGROUND Multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSDs) are 2 similar but distinct diseases. These diseases were difficult to distinguish from each other until aquaporin-4-IgG (AQP-4-IgG) was discovered. The accurate identification of these 2 diseases is crucial for appropriate drug treatment in clinical practice. Herein, we report a case of AQP-4-IgG seroconversion with magnetic resonance imaging (MRI) findings suggestive of MS. CASE REPORT A 54-year-old woman developed weakness in her right lower extremity that gradually returned to normal 4 years ago. Recently, she was admitted to the hospital for numbness and weakness of both lower limbs and the right upper limb for more than 10 days. The clinical and MRI features of the patient suggested a high susceptibility for misdiagnosis of MS. However, careful observation of the MRI revealed the presence of atypical MS lesions ("red flag" signs), indicating the possibility of other diagnoses in this patient. After further examination, serum AQP-4-IgG was detected, suggesting the potential presence of another disorder, NMOSD, in the patient. CONCLUSIONS Attention should be given to the identification of MS MRI "red flag" signs. Even for patients with a high suspicion of MS, it is necessary to conduct antibody tests for AQP-4-IgG, MOG-IgG and other relevant markers to screen for associated diseases because MS disease-modifying therapy approaches may lead to a deterioration in the state of NMOSD patients. Analyzing this case can help us to further distinguish the differences between these 2 types of diseases, which has important practical clinical value.


Assuntos
Esclerose Múltipla , Feminino , Humanos , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/patologia , Glicoproteína Mielina-Oligodendrócito , Autoanticorpos , Aquaporina 4 , Neuroimagem , Imunoglobulina G
2.
Medicine (Baltimore) ; 102(20): e33855, 2023 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-37335699

RESUMO

INTRODUCTION: Contrast-induced encephalopathy (CIE) is a rare complication associated with the use of contrast media. New contrast agents make contrast complications increasingly rare. The diagnosis of CIE is challenging, particularly in patients with acute ischemic stroke. Neuroimaging results for patients with CIE can also be highly variable. PATIENT CONCERNS: A 63-year-old man with severe internal carotid artery stenosis who experienced several symptoms, including dizziness, nausea, vomiting, fever, and blurred vision after being administered the contrast agent iodixanol. DIAGNOSES: Multiple CT and MRI brain scans were performed. After excluding other differential diagnoses such as electrolytes imbalance, hypo/hyperglycemia and other neurological emergencies such as cerebral hemorrhage, cerebral infarction, the final diagnosis of CIE was made. INTERVENTION: Treatment consisted of adequate hydration, intravenous dexamethasone, mannitol, and anticonvulsants. OUTCOME: The patient demonstrated progressive neurological improvement, and recovered from all symptoms on the fifth day. Follow-up at 3 months shows a good prognosis for patients. CONCLUSION: Patients with CIE may have a high signal on diffusion-weighted imaging and a low signal on apparent diffusion coefficient brain MRI. This is similar to the MRI findings in acute stroke. This needs to be distinguished from acute cerebral infarction and suggests that we should closely monitor patients' neurological symptoms at the time of cerebral angiography and after the investigations.


Assuntos
AVC Isquêmico , Acidente Vascular Cerebral , Masculino , Humanos , Pessoa de Meia-Idade , Angiografia Cerebral , Acidente Vascular Cerebral/diagnóstico , Imageamento por Ressonância Magnética/métodos , Infarto Cerebral/diagnóstico por imagem , Infarto Cerebral/etiologia
3.
Front Chem ; 9: 808870, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34957056

RESUMO

One new 3,4-seco-17,13-friedo-lanostane triterpenoid heilaohuacid A (1), one new 3,4-seco-17,14-friedo-lanostane triterpenoid heilaohuacid B (2), five new 3,4-seco-lanostane triterpenoids heilaohuacids C-D (3-4) and heilaohumethylesters A-C (7-9), one new 3,4-seco-cycloartane triterpenoid heilaohuacid E (5), and one new intact-lanostane triterpenoid heilaohuacid F (6), together with twenty-two known analogues (10-31), were isolated from heilaohu. Their structures were determined using HR-ESI-MS data, 1D and 2D NMR spectra, 13C NMR calculations, and electronic circular dichroism (ECD) calculations. Heilaohuacids A and B (1 and 2) contain a 3,4-seco ring A and unprecedented migration of Me-18 from C-13 to C-17 or C-14 to C-18. This type of lanostane triterpenoid derivatives was rarely reported so far. More importantly, all compounds against inflammatory cytokines IL-6 and TNF-α levels on LPS-induced RAW 264.7 macrophages were evaluated, and compounds 4 and 31 significantly inhibited the release level of IL-6 with IC50 values of 8.15 and 9.86 µM, respectively. Meanwhile, compounds 17, 18, and 31 significantly inhibited proliferation of rheumatoid arthritis-fibroblastoid synovial (RA-FLS) cells in vitro with IC50 values of 7.52, 8.85, and 7.97 µM, respectively.

4.
J AOAC Int ; 103(1): 117-123, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31451136

RESUMO

BACKGROUND: Bupi Yiqi No. 1 Recipe (BPYQ), a traditional Chinese medicine formula, has been widely used as a treatment of multidrug resistance during chemotherapy in colorectal cancer and for the prevention of gastrointestinal cancer recurrence for decades. OBJECTIVE: In this study, a rapid, reliable, and accurate ultrahigh-performance LC (UHPLC) coupled with electrospray ionization (ESI)-tandem MS (MS/MS) method was developed for the simultaneous determination of 12 major bioactive components, including protocatechuic acid, astilbin, rutin, calycosin-7-O-ß-D-glucoside, ginsenoside Re, ononin, isoliquiritigenin, calycosin, apigenin, ginsenoside Rb1, formononetin, and glycyrrhizic acid in BPYQ. METHODS: The chromatographic separation of the analytes was achieved on a Poroshell 120 SB-Aq column (50 × 2.1 mm, 1.7 µm) with a mobile phase of acetonitrile and 0.1% (v/v) formic acid aqueous solution. The flow rate and column temperature were set at 0.4 mL/min and 30°C, respectively. Mass spectrometric detection of the analyses was performed on multiple reaction monitoring mode in positive and negative ESI mode. RESULTS: The established UHPLC-ESI-MS/MS method was validated in terms of the linearity, precision, repeatability, stability, and accuracy. All calibration curves of the 12 compounds showed good linearity, with correlation coefficients (r) greater than 0.9980 within the test ranges. The LODs and LOQs for the 12 compounds were in the ranges of 0.08-1.32 and 0.27-5.28 ng/mL, respectively. The average recoveries of all the standard compounds were between 98.4 and 102.9%, and their relative SD values ranged from 1.24 to 3.78%. CONCLUSIONS: The proposed method can provide a meaningful basis for the QC of BPYQ. HIGHLIGHTS: The established UHPLC-ESI-MS/MS method was demonstrated to be a powerful tool for quantifying the 12 compounds in BPYQ.


Assuntos
Medicamentos de Ervas Chinesas , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Medicina Tradicional Chinesa , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray
5.
Fitoterapia ; 140: 104441, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31778760

RESUMO

In the present work, we reported the triterpenoids isolated from n-butanol fraction of Kadsura heteroclita which is a Tujia ethnomedicine with trivial name "Xuetong". This effort resulted in the isolation of six unpresented triterpenoids xuetongsu A-F (1-6), along with five known triterpenoids (7-11). The structures of the reported compounds were established on the 1D, and 2D NMR and HRESIMS spectra, along with CD spectroscopic analysis. Moreover, the absolute stereochemistry of compound 7 was determined by X-ray diffraction analysis. Antioxidant and cytotoxic activities were evaluated for all isolated compounds, compound 7 shown weak cytotoxic activity against HL-60 with IC50 value of 50.0 µM.


Assuntos
Kadsura/química , Caules de Planta/química , Triterpenos/química , China , Células HL-60 , Humanos , Estrutura Molecular , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Triterpenos/isolamento & purificação
6.
Phytochemistry ; 169: 112178, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31669819

RESUMO

In the present work, we take advantage of the characteristic NMR signal (δC-10 = 96.0-99.9) for guiding the isolation of schinortriterpenoids (SNTs) from n-butanol fraction of stems of Kadsura heteroclita which is a Tujia ethnomedicine with trivial name "Xuetong". This effort resulted in the identification of three unreported 3,4:9,10-disecocycloartane triterpenoids xuetongdilactones A-C and three undescribed SNTs xuetongdilactones D-F, along with two known SNTs, namely, wuweizidilactone B and micrandilactone B. The structures of the unreported compounds were established based on 1D, and 2D NMR, HRESIMS, and ECD spectroscopic data analysis. The absolute stereochemistry of xuetongdilactone A was determined by X-ray diffraction analysis along with ECD calculation. The antioxidant and cytotoxic activities were evaluated for all the isolated compounds.


Assuntos
Kadsura/química , Caules de Planta/química , Triterpenos/farmacologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Triterpenos/química , Triterpenos/isolamento & purificação
7.
Mult Scler Relat Disord ; 37: 101480, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31706165

RESUMO

We report a case of neuromyelitis optica spectrum disorders (NMOSD) with complete loss of vision in the left eye in a patient who was not satisfied with the effect of methylprednisolone therapy, which was improved by HA280 immunoadsorption (IA) therapy. HA280 is a relatively cheaper IA column (made in China) often used in the treatment of rheumatoid immune-related diseases. HA280 can effectively remove inflammatory markers in serum. However, whether the HA280 IA column is suitable for NMOSD is unknown. This case suggests that the HA280 IA column has a potential therapeutic effect on NMOSD and may be an alternative treatment for steroid-resistant NMOSD. There may be therapeutic targets other than anti-AQP4 antibody. Identifying the inflammatory substances that could be removed to contribute to NMOSD recovery is worthy of further study, and the results could provide new ideas for acute NMOSD treatment. Moreover, the HA280 IA column is relatively cheap and allows lower-income families to use it.


Assuntos
Neuromielite Óptica/terapia , Plasmaferese , Adulto , Cegueira/etiologia , Feminino , Humanos , Neuromielite Óptica/complicações , Plasmaferese/instrumentação
8.
Fitoterapia ; 139: 104368, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31629046

RESUMO

Four new dibenzocyclooctadiene lignans, named heilaohusus A-D (1-4), one new arylnaphthalene lignan named heilaohusu E (5), and seven known analogues (6-12) were isolated from the roots of Kadsura coccinea. Their structures and configurations were elucidated by a combination of HR-ESI-MS, 1H NMR, 13C NMR, HSQC, HMBC, NOESY and CD spectra. Among the known compounds, compounds 6 and 8-12 were isolated from this plant for the first time. All of compounds were evaluated for their cytotoxicity activities, compounds 3, 6 and 7 showed weak cytotoxicity against four human cancer cell lines (HepG-2, HCT-116, BGC-823 and Hela) with IC50 values range from 13.04 to 21.93 µM. Compounds 1 and 7 demonstrated potential anti-RA (rheumatoid arthritis) activity against RA-FLS cell line with IC50 values of 14.57 and 11.70 µM, respectively.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Antirreumáticos/farmacologia , Kadsura/química , Lignanas/farmacologia , Antineoplásicos Fitogênicos/isolamento & purificação , Antirreumáticos/isolamento & purificação , Linhagem Celular Tumoral , China , Ciclo-Octanos , Humanos , Lignanas/isolamento & purificação , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Raízes de Plantas/química
9.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 34(2): 141-147, 2018 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-29673456

RESUMO

Objective To observe the effects of microRNA-7 (miR-7) on intracerebral hemorrhage-induced brain injury in rats and explore the underlying mechanism. Methods Seventy-five SD rats were used to establish intracerebral hemorrhage model through injection of VII collagenase into the pallidum. These rats were then divided into control, miR-7 agomir, agomir control, miR-7 antagomir and antagomir control groups, containing 15 animals in each group. On day 2 after modeling, rats were injected with 10 µL of physiological saline, miR-7 agomir, agomir control, miR-7 antagomir and antagomir control via the lateral ventricle, respectively. On day 7 after modeling, the neurological function score was evaluated, and then all rats were killed to obtain brain tissue. HE staining was conducted to observe the pathological changes of cerebral tissue. Brain water content was examined by the dried and wet mass. The expressions of miR-7, glial fibrillary acidic protein (GFAP) and epidermal growth factor receptor (EGFR) in the cerebral tissue around hemotomas were detected using real-time quantitative PCR. Western blotting was used to analyze the levels of GFAP, EGFR, signal transducers and activators of transcription 3 (STAT3) and phosphorylated STAT3 (p-STAT3) in the cerebral tissue around hemotomas. In addition, bioinformatics was used to predict the binding of miR-7 to EGFR. Both wild type luciferase reporter gene vector and corresponding mutant vector were constructed and then transfected into HEK293T cells along with miR-7 mimic for detecting the luciferase activity. Results In comparison with control group, miR-7 agomir markedly increased miR-7 level, alleviated the pathological impairment of cerebral tissues, reduced neurological function score and brain water content, and attenuated the expression levels of GFAP and EGFR and p-STAT3/STAT3 ratio in the cerebral tissue around hemotomas. An opposite effect was observed in response to miR-7 antagomir. However, their negative controls had no impact on the above indicators. There was a binding site between 3'-untranslated region within the EGFR and miR-7. Moreover, miR-7 mimic markedly decreased the luciferase activity of the reporter gene of wild type, but not its mutant. Conclusion The miR-7 can inhibit the EGFR/STAT3 signaling pathway to antagonize astrocyte activation, leading to the protection against brain injury after intracerebral hemorrhage in rats.


Assuntos
Lesões Encefálicas/metabolismo , Hemorragia Cerebral/complicações , Receptores ErbB/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Astrócitos/metabolismo , Lesões Encefálicas/etiologia , Lesões Encefálicas/genética , Lesões Encefálicas/terapia , Modelos Animais de Doenças , Receptores ErbB/genética , Proteína Glial Fibrilar Ácida/genética , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Fator de Transcrição STAT3/genética , Transdução de Sinais
10.
RSC Adv ; 8(41): 22866-22875, 2018 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35540152

RESUMO

Cerebral infarction (CI) is one of the most common cerebrovascular diseases and remains a major health problem worldwide. In this study, we evaluated the potential diagnostic biomarkers and important relevant metabolic pathways associated with CI. Metabolomics based on gas chromatography-mass spectrometry coupled with the multivariate pattern recognition technique were used to characterize the potential serum metabolic profiles of CI. Forty healthy controls and thirty-three cerebral infarction patients were recruited for the nontargeted global metabolites' study and subsequent targeted fatty acid analysis. Overall, thirty-four endogenous metabolites were found in serum from the untargeted global study, four of which were detected to be significantly different between the CI group and healthy controls, including l-lysine, octadecanoic acid (fatty acid), l-tyrosine and lactic acid. Additionally, fourteen free fatty acids were identified by the subsequent targeted fatty acid analysis, and seven of them were detected to be significantly different between the CI group and healthy controls, which were mainly associated with arachidonic acid metabolism and fatty acid metabolism. Our results suggest several potential diagnostic biomarkers, and serum metabolism research is demonstrated as a powerful tool to explore the pathogenesis of CI.

11.
Oncotarget ; 8(42): 72748-72754, 2017 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-29069823

RESUMO

BACKGROUND: Temporal lobe epilepsy is the second most common neurological disorders characterized by recurrent spontaneous seizures. MicroRNAs play a vital role in regulating synaptic plasticity, brain development and post-transcriptional expression of proteins. In both animal models of epilepsy and human patients, miR-134, a brain-specific microRNA has recently been identified as a potential regulator of epileptogenesis. METHODS: microRNA identified as targets for the actions of valproic acid (VPA) are known to have important effects in brain function. In this study, 59 new-onset epilepsy patients and 20 controls matched by sex and age were enrolled. Patients with a score < 3 were allocated into the mild group, 3-5 into the moderate group and >5 into the severe group. The plasma miRNA-134 level was quantitatively measured using real-time PCR. RESULTS: Plasma miRNA-134 level in new-onset epilepsy patients was significantly up-regulated when compared with that in healthy controls, and then considerably down-regulated after oral intake of valproic acid medication. The up-regulated plasma miRNA-134 levels may be directly associated with the pathophysiology and severity of epilepsy. CONCLUSION: Plasma miRNA-134 in epilepsy may be considered as a potential peripheral biomarker that responds to the incidence of epilepsy and associates with use of anti-epilepsy drugs.

12.
J Mol Neurosci ; 63(2): 159-164, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28856571

RESUMO

It is well known that extracellular deposition of amyloid-ß (Aß) peptide and microglia-mediated neuroinflammation are major hallmarks of Alzheimer's disease (AD). Interferon regulatory factor-8 (IRF-8), an important transcription factor of the IRF family, is highly restricted in microglia in brains. The expression pattern and function of IRF-8 in AD need to be elucidated in order to provide novel therapies for the treatment of AD. In this study, our results indicated that expression of IRF-8 is significantly elevated in the brains and microglia of AD transgenic model Tg2576 mice. Notably, in vitro cell culture and reporter luciferase assay show that Aß1-40 treatment promotes expression of IRF-8 at the transcriptional level. Silencing of IRF-8 in microglia abolished Aß1-40-induced elevation in typical activated microglia-related genes, including the microglial innate response receptor toll-like receptor 2 (TLR2), the chemotaxis gene purinergic receptor P2Y12R, and the proinflammatory cytokine IL-1ß. However, overexpression of IRF-8 exacerbated the elevated expression of these proteins. Finally, the JAK2/STAT-1 pathway was found to mediate Aß1-40-induced elevation of IRF-8. Overall, this is the first time to report that IRF-8 is involved in microglial activation and neuroinflammation in AD.


Assuntos
Doença de Alzheimer/metabolismo , Fatores Reguladores de Interferon/metabolismo , Microglia/metabolismo , Peptídeos beta-Amiloides/toxicidade , Animais , Células Cultivadas , Fatores Reguladores de Interferon/genética , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Janus Quinase 2/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fragmentos de Peptídeos/toxicidade , Receptores Purinérgicos/genética , Receptores Purinérgicos/metabolismo , Fator de Transcrição STAT1/metabolismo , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/metabolismo
13.
IUBMB Life ; 66(11): 786-92, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25469469

RESUMO

Growth arrest and DNA-damage-inducible protein 45α (GADD45α) is an important member of the family of growth arrest and DNA damage-inducible (GADD) proteins. The expression patterns and possible roles of GADD45α in Parkinson's disease (PD) are so far less understood. In this study, we found that 1-methyl-4-phenylpyridinium (MPP+) treatment up-regulates the expression of GADD45α in both a time-dependent manner and a dose-dependent manner in human dopamine neuroblastoma M17 cells. The up-regulation of GADD45α was abolished by pretreatment with the c-Jun N-terminal kinases (JNK) inhibitor SP600125 but not the p38 specific inhibitor SB203580. Further study revealed that c-Jun silencing abolished the effects of MPP+ on the expression of GADD45α. Important, ChIP studies verified the ability of c-Jun to bind to the GADD45 promoter. In addition, we found that inhibition of GADD45α by small RNA interference exacerbates the impaired cell viability, LDH release, and apoptosis induced by MPP+. Correspondingly, silence of GADD45 exacerbated Caspase-3 activation induced by MPP+. These data suggested a neuroprotective effect of GADD45α against MPP+ neurotoxicity.


Assuntos
1-Metil-4-fenilpiridínio/farmacologia , Proteínas de Ciclo Celular/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Nucleares/metabolismo , Doença de Parkinson/tratamento farmacológico , 1-Metil-4-fenilpiridínio/uso terapêutico , Análise de Variância , Antracenos/farmacologia , Western Blotting , Caspase 3/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Linhagem Celular Tumoral , Sobrevivência Celular , Imunoprecipitação da Cromatina , Relação Dose-Resposta a Droga , Humanos , Imidazóis , Marcação In Situ das Extremidades Cortadas , Proteínas Nucleares/antagonistas & inibidores , Doença de Parkinson/metabolismo , Piridinas , Interferência de RNA , Reação em Cadeia da Polimerase em Tempo Real , Sais de Tetrazólio , Tiazóis
14.
J Immunol ; 190(11): 5436-45, 2013 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23616572

RESUMO

Although modifier genes are extensively studied in various diseases, little is known about modifier genes that regulate autoimmune diseases. Autoimmune disease caused by the Fas(lpr) mutation depends on the genetic background of mouse strains, suggesting a crucial role of modifier genes. MRL/MpJ-Fas(lpr) (MRL/lpr) and AKR/lpr mice develop severe and mild lupus-like autoimmune disease, respectively, whereas this mutation does not cause disease on C57BL/6 (B6) or C3H background. Both MRL and AKR carry the same haplotype of the Cd72 gene encoding an inhibitory BCR coreceptor (CD72(c)), and CD72(c) contains several amino acid substitutions and a deletion in the extracellular region compared with CD72(a) and CD72(b). To address the role of Cd72(c) locus in the regulation of Fas(lpr)-induced autoimmune disease, we generated B6.CD72(c)/lpr and MRL.CD72(b)/lpr congenic mice. Introduction of the chromosomal interval containing Cd72(c) did not cause disease in B6 mice by itself, but caused development of lupus-like disease in the presence of Fas(lpr) on B6 background, clearly demonstrating that this interval contains the modifier gene that regulates Fas(lpr)-induced autoimmune disease. Conversely, MRL.CD72(b)/lpr congenic mice showed milder disease compared with MRL/lpr mice. We further demonstrated that Cd72(c) is a hypofunctional allele in BCR signal inhibition and that CD72 deficiency induces severe autoimmune disease in the presence of Fas(lpr). These results strongly suggest that the Cd72(c) is a crucial modifier gene that regulates Fas(lpr)-induced autoimmune disease due to its reduced activity of B cell signal regulation.


Assuntos
Antígenos CD/genética , Antígenos de Diferenciação de Linfócitos B/genética , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Regulação da Expressão Gênica , Receptor fas/genética , Animais , Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos B/imunologia , Autoanticorpos/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Linhagem Celular , Feminino , Imunofenotipagem , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Linfonodos/citologia , Camundongos , Camundongos Congênicos , Camundongos Endogâmicos MRL lpr , Camundongos Knockout , Mutação , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Baço/citologia , Receptor fas/imunologia
15.
PLoS One ; 5(1): e8815, 2010 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-20098688

RESUMO

IgG-containing B cell antigen receptor (IgG-BCR), the BCR mostly expressed on memory B cells, contains a distinct signaling function from IgM-BCR or IgD-BCR expressed on naïve B cells. Because naïve B cells transgenic for IgG exhibit augmented response to antigens similar to memory B cells, the distinct signaling function of IgG-BCR appears to play a role in augmented antibody responses of memory B cells. However, how IgG-BCR signaling augments B cell responses is not yet well understood. Here we demonstrate that B cells from IgG-transgenic mice are anergic with defect in generation of BCR signaling upon BCR ligation. However, these IgG-transgenic B cells generate markedly augmented antibody response to a T cell-dependent antigen, probably due to hyper-responsiveness to a T cell-derived signal through CD40. Both BCR signaling defect and augmented response to CD40 ligation are partially restored in xid IgG-transgenic mice in which BCR signaling is down-modulated due to a loss-of-function mutation in the tyrosine kinase Btk crucial for BCR signaling. Thus, IgG-BCR induces augmented B cell responses in the absence of antigen-induced BCR signaling probably through high ligand-independent BCR signaling that may "idle" B cells to make them ready to respond to T cell help. This finding strongly suggests a crucial role of ligand-independent signaling in receptor function.


Assuntos
Antígenos/imunologia , Linfócitos B/imunologia , Imunoglobulina G/imunologia , Transdução de Sinais , Tirosina Quinase da Agamaglobulinemia , Animais , Anergia Clonal , Imunoglobulina G/genética , Camundongos , Camundongos Transgênicos , Proteínas Tirosina Quinases/genética
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