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1.
Clin Neurophysiol ; 122(9): 1718-25, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21396882

RESUMO

OBJECTIVE: To determine the electrophysiological characteristics of frontotemporal dementia (FTD) and the distinction with Alzheimer's disease (AD). METHODS: We performed analyses of global field power (GFP) which is a measure of whole brain electric field strength, and EEG neuroimaging analyses with sLORETA (standardized low resolution electromagnetic tomography), in the mild stages of FTD (n = 19; mean age = 68.11 ± 7.77) and AD (n = 19; mean age = 69.42 ± 9.57) patients, and normal control (NC) subjects (n = 22; mean age = 66.13 ± 6.02). RESULTS: In the GFP analysis, significant group effects were observed in the delta (1.5-6.0 Hz), alpha1 (8.5-10.0 Hz), and beta1 (12.5-18.0 Hz) bands. In sLORETA analysis, differences in activity were observed in the alpha1 band (NC > FTD) in the orbital frontal and temporal lobe, in the delta band (AD>NC) in widespread areas including the frontal lobe, and in the beta1 band (FTD > AD) in the parietal lobe and sensorimotor area. CONCLUSIONS: Differential patterns of brain regions and EEG frequency bands were observed between the FTD and AD groups in terms of pathological activity. SIGNIFICANCE: FTD and AD patients in the early stages displayed different patterns in the cortical localization of oscillatory activity across different frequency bands.


Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/fisiopatologia , Demência Frontotemporal/diagnóstico , Demência Frontotemporal/fisiopatologia , Processamento de Sinais Assistido por Computador , Idoso , Idoso de 80 Anos ou mais , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
2.
Lupus ; 19(3): 307-12, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20015915

RESUMO

The reactivities to individual U1 small nuclear ribonucleoprotein (snRNP) components and their relationship to clinical features in patients with anti-U1 snRNP antibodies were examined. We evaluated 114 patients with connective tissue disease whose sera were positive for anti-U1 snRNP antibodies, but negative for anti-Sm antibodies. Antibodies to the U1 snRNP polypeptides 70K, A, and C were detected using subunit-specific enzyme-linked immunosorbent assays and antibodies to U1 small nuclear RNA (snRNA) were identified by an immunoprecipitation assay using deproteinized HeLa cell extracts. The clinical features were retrospectively obtained by chart review and prospectively collected after study entry. The pattern of antibody reactivities to U1 snRNP components varied among patients. The frequency of anti-70K, anti-A, anti-C, and anti-U1 snRNA antibodies was 60%, 86%, 74%, and 46%, respectively. There was no relationship between each reactivity and the clinical findings, but the presence of reactivities to increasing numbers of U1 snRNP components was correlated with sclerodactyly, shortness of the sublingual frenulum, esophageal dysfunction, and a lack of persistent proteinurea (p < 0.05 for all comparisons). The detection of autoantibody reactivities to individual components of the U1 snRNP particle is potentially useful for predicting the clinical course in patients with connective tissue disease and anti-U1 snRNP antibodies.


Assuntos
Autoanticorpos/imunologia , Doenças do Tecido Conjuntivo/imunologia , Ribonucleoproteína Nuclear Pequena U1/imunologia , Adulto , Idoso , Doenças do Tecido Conjuntivo/fisiopatologia , Ensaio de Imunoadsorção Enzimática , Feminino , Células HeLa , Humanos , Imunoprecipitação/métodos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Adulto Jovem
3.
Br J Pharmacol ; 158(3): 879-87, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19694723

RESUMO

BACKGROUND AND PURPOSE: The lipid phosphatase known as SH2 domain-containing inositol 5'-phosphatase 2 (SHIP2) plays an important role in the regulation of the intracellular insulin signalling pathway. Recent studies have suggested that inhibition of SHIP2 could produce significant benefits in treatment of type 2 diabetes. However, there were no small molecule SHIP2 inhibitors and we, therefore, aimed to identify this type of compound. EXPERIMENTAL APPROACH: The phosphatase assay with malachite green was used for high-throughput screening. The pharmacological profiles of suitable compounds were further characterized in phosphatase assays, cellular assays and oral administration in normal and diabetic (db/db) mice. KEY RESULTS: During high-throughput screening, AS1949490 was identified as a potent SHIP2 inhibitor (IC(50)= 0.62 microM for SHIP2). This compound was also selective for SHIP2 relative to other intracellular phosphatases. In L6 myotubes, AS1949490 increased the phosphorylation of Akt, glucose consumption and glucose uptake. In FAO hepatocytes, AS1949490 suppressed gluconeogenesis. Acute administration of AS1949490 inhibited the expression of gluconeogenic genes in the livers of normal mice. Chronic treatment of diabetic db/db mice with AS1949490 significantly lowered the plasma glucose level and improved glucose intolerance. These in vivo effects were based in part on the activation of intracellular insulin signalling pathways in the liver. CONCLUSIONS AND IMPLICATIONS: This is the first report of a small molecule inhibitor of SHIP2. This compound will help to elucidate the physiological functions of SHIP2 and its involvement in various diseases, such as type 2 diabetes.


Assuntos
Monoéster Fosfórico Hidrolases/metabolismo , Tiofenos/farmacologia , Animais , Linhagem Celular , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/genética , Glucose/metabolismo , Intolerância à Glucose/sangue , Intolerância à Glucose/tratamento farmacológico , Humanos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Inositol Polifosfato 5-Fosfatases , Insulina/fisiologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/genética , Fosforilação , Período Pós-Prandial , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Tiofenos/uso terapêutico , Domínios de Homologia de src
4.
Clin Rheumatol ; 28(2): 227-9, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19082529

RESUMO

We describe a patient who presented with polymyositis with anti-Jo-1 antibodies at 18 years after the onset of rheumatoid arthritis and was successfully treated with the immunosuppressive drug mizoribine at the time of exacerbation. She had developed diabetes mellitus, cerebral infarction, and myocardial infarction after high-dose steroid therapy was initiated. Therefore, an immunosuppressant was preferred as the second-line agent. Treatment with 150 mg/day of mizoribine and 8 mg/day of prednisolone resulted in eventual normalization of muscle enzyme levels. Mizoribine is a purine antimetabolite that inhibits T cell activation/proliferation and B cell proliferation. The potential efficacy of mizoribine for polymyositis was suggested by this case.


Assuntos
Imunossupressores/uso terapêutico , Polimiosite/tratamento farmacológico , Ribonucleosídeos/uso terapêutico , Infarto Cerebral/induzido quimicamente , Feminino , Humanos , Pessoa de Meia-Idade , Infarto do Miocárdio/induzido quimicamente , Esteroides/efeitos adversos , Esteroides/uso terapêutico , Resultado do Tratamento
5.
Clin Exp Rheumatol ; 23(5): 609-15, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16173235

RESUMO

OBJECTIVE: The clinical and laboratory features of seven Japanese patients with anti-aminoacyl-tRNA synthetase (ARS) autoantibodies against PL-7 (anti-threonyl-tRNA synthetase) were analyzed and compared with previously published findings. METHODS: Serum samples from 1,135 Japanese patients with various autoimmune diseases were screened for anti-PL-7 antibodies using RNA and protein immunoprecipitation assays. The patients whose sera contained anti-PL-7 antibodies were assessed regarding clinical symptoms and clinical course. RESULTS: Sera from seven patients were found to have anti-PL-7 antibodies. These autoantibodies were associated with polymyositis/dermatomyositis (PM/DM) and/or interstitial lung disease (ILD). The clinical diagnoses of these seven patients were PM - systemic sclerosis (SSc) overlap (5 patients), DM (1 patient) and idiopathic pulmonary fibrosis (IPF) (1 patient). All patients had ILD with a chronic course and six also had arthritis (85%) and five sclerodactyly (71%). CONCLUSIONS: These results indicate that anti-PL-7 autoantibodies are closely associated with PM-SSc overlap as well as ILD, arthritis and sclerodactyly in our series of Japanese patients.


Assuntos
Autoanticorpos/imunologia , Doenças Autoimunes/imunologia , Treonina-tRNA Ligase/imunologia , Adulto , Povo Asiático , Doenças Autoimunes/etnologia , Dermatomiosite/etnologia , Dermatomiosite/imunologia , Feminino , Humanos , Doenças Pulmonares Intersticiais/etnologia , Doenças Pulmonares Intersticiais/imunologia , Masculino , Pessoa de Meia-Idade , Polimiosite/etnologia , Polimiosite/imunologia , Fibrose Pulmonar/etnologia , Fibrose Pulmonar/imunologia , Escleroderma Sistêmico/etnologia , Escleroderma Sistêmico/imunologia
6.
Clin Exp Rheumatol ; 23(6): 885-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16396710

RESUMO

Behçet's disease (BD) is a chronic multisystem inflammatory disorder characterized by recurrent oral and genital ulcers, skin eruptions and uveitis. Neurological, gastrointestinal, and musculoskeletal systems are also involved. Although venous and arterial vasculitis occur in up to one-third of patients, intracardiac thrombus is a very rare complication. We herein report the case of a 46-year-old man with BD who presented with a large right atrial thrombus. Within a month after surgical removal, the thrombus recurred and was successfully treated with immunosuppressants that included prednisolone and cyclophosphamide.


Assuntos
Síndrome de Behçet/tratamento farmacológico , Trombose Coronária/tratamento farmacológico , Ciclofosfamida/administração & dosagem , Imunossupressores/administração & dosagem , Prednisolona/administração & dosagem , Síndrome de Behçet/complicações , Trombose Coronária/complicações , Trombose Coronária/diagnóstico por imagem , Quimioterapia Combinada , Ecocardiografia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva
7.
Horm Metab Res ; 36(8): 513-8, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15326559

RESUMO

To assess the correlation between hyperglycemia and glucose catabolic gene levels in diabetic and healthy mice, we determined mRNA levels of pivotal proteins such as glucose transporters, hexokinase II, glycogen synthase, glutamine:fructose-6-phosphate amidotransferase and uncoupling proteins. Both KK and KKAy mice showed marked decreases of Glut1 and Glut4 mRNA levels in soleus compared to C57BL; db/db and ob/ob mice exhibited significantly decreased Glut4 mRNA levels, but not Glut1, in soleus. KK and KKAy mice showed a decrease of soleus HKII gene level, which may indicate decreased intracellular catabolism of glucose. Likewise, GS mRNA level was decreased in soleus muscle tissue in KK and KKAy mice. GFAT mRNA levels was no different between hyperglycemic and normoglycemic mice. In contrast, UCP2 and UCP3 mRNA levels were higher in KK and KKAy mice. Conversely, db/db and ob/ob mice showed a significant decrease in UCP3 mRNA. Individual correlation analysis indicated that the decrease in Glut4 gene levels was only observed in hyperglycemic mice. The more important observation is that the glucose catabolic genes do not exhibit any clear coordinate expression. Abnormal expression of glucose catabolic genes may contribute to hyperglycemia and muscle insulin resistance in these four strains.


Assuntos
Glucose/metabolismo , Hiperglicemia/metabolismo , Músculo Esquelético/metabolismo , RNA Mensageiro/metabolismo , Animais , Glicemia/metabolismo , Peso Corporal , Diabetes Mellitus/sangue , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Transportador de Glucose Tipo 1 , Transportador de Glucose Tipo 4 , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/genética , Glicogênio Sintase/genética , Hexoquinase/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Proteínas de Transporte de Monossacarídeos/genética , Proteínas Musculares/genética
8.
Clin Exp Immunol ; 136(3): 568-73, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15147362

RESUMO

We have reported previously that p95c, a novel 95-kDa cytosolic protein, was the target of autoantibodies in sera of patients with autoimmune hepatic diseases. We studied 30 sera that were shown previously to immunoprecipitate a 95 kDa protein from [(35)S]-methionine-labelled HeLa lysates and had a specific precipitin band in immunodiffusion. Thirteen sera were available to test the ability of p95c antibodies to inhibit nuclear envelope assembly in an in vitro assay in which confocal fluorescence microscopy was also used to identify the stages at which nuclear assembly was inhibited. The percentage inhibition of nuclear envelope assembly of the 13 sera ranged from 7% to 99% and nuclear envelope assembly and the swelling of nucleus was inhibited at several stages. The percentage inhibition of nuclear assembly was correlated with the titre of anti-p95c as determined by immunodiffusion. To confirm the identity of this autoantigen, we used a full-length cDNA of the p97/valosin-containing protein (VCP) to produce a radiolabelled recombinant protein that was then used in an immunoprecipitation (IP) assay. Our study demonstrated that 12 of the 13 (93%) human sera with antibodies to p95c immunoprecipitated recombinant p97/VCP. Because p95c and p97 have similar molecular masses and cell localization, and because the majority of sera bind recombinant p97/VCP and anti-p95c antibodies inhibit nuclear assembly, this is compelling evidence that p95c and p97/VCP are identical.


Assuntos
Autoanticorpos/imunologia , Proteínas de Ciclo Celular/imunologia , Cirrose Hepática Biliar/imunologia , Adenosina Trifosfatases , Reações Antígeno-Anticorpo , Núcleo Celular/imunologia , Feminino , Humanos , Fígado/patologia , Cirrose Hepática Biliar/patologia , Masculino , Microscopia Confocal , Testes de Precipitina , Proteína com Valosina
9.
Clin Exp Rheumatol ; 20(3): 407-10, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12102481

RESUMO

Gastrointestinal involvement is often seen in patients with systemic lupus erythematosus (SLE). All parts of the gastrointestinal tract may be affected. However, rectal involvement at onset is rare. We describe here a case of SLE in which rectal ulcers due to vasculitis occurred as the initial manifestation of the disease without involvement of any other organ. The ulcers worsened, along with the appearance of lupus nephritis 5 years later When steroid therapy was initiated, there was rapid clinical and radiographic improvement. Our case suggests that rectal ulcer is a rare but important complication of SLE and can represent the initial and sole clinical manifestation of the disease.


Assuntos
Lúpus Eritematoso Sistêmico/diagnóstico , Reto/patologia , Úlcera/diagnóstico , Vasculite/diagnóstico , Adulto , Diagnóstico Diferencial , Endoscópios Gastrointestinais , Humanos , Masculino
10.
Rheumatology (Oxford) ; 40(12): 1398-404, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11752512

RESUMO

OBJECTIVE: To determine cytokines and MHC class II alleles in Japanese patients with adult Still's disease (ASD) and clarify the association between those profiles and chronic articular disease. METHODS: Of 35 patients with ASD (13 men, 22 women, mean age at onset 34.0 yr), 17 (49%) had chronic arthritis (>6 months, chronic articular ASD) and 18 (51%) lacked chronic arthritis (systemic ASD). Cytokines and cytokine receptors in sera were measured by ELISA. Correlations of each cytokine with disease activity or C-reactive protein (CRP) were determined. MHC class II alleles were examined by polymerase chain reaction methods. RESULTS: In chronic articular ASD, female gender was more frequent and liver dysfunction and myalgia were rarer than in systemic ASD. In active disease, the white blood cell count was lower, but total IgG was greater in patients with chronic articular ASD than in those with systemic ASD. Tumour necrosis factor (TNF) alpha, soluble TNF receptor 2 and interleukin (IL)-18 were increased in both types of ASD, even in remission. Soluble IL-2 receptors, IL-4 and IL-18 levels were correlated with disease activity or CRP value only in chronic articular ASD. Interferon gamma and IL-8 remained increased only in chronic articular ASD, even when disease activity, including IL-6 and CRP, was low. DRB1*1501 (DR2) and DRB1*1201 (DR5) alleles were more frequent in chronic articular than in systemic ASD, whereas DQB1*0602 (DQ1) was frequently observed in both types of ASD. CONCLUSION: The present study suggests that ASD with chronic articular disease has distinct clinical, cytokine and immunogenetic profiles.


Assuntos
Artrite/imunologia , Citocinas/sangue , Doença de Still de Início Tardio/imunologia , Adulto , Antígenos CD/sangue , Artrite/genética , Biomarcadores , Proteína C-Reativa/metabolismo , Doença Crônica , Feminino , Antígenos HLA-DQ/genética , Cadeias beta de HLA-DQ , Antígenos HLA-DR/genética , Cadeias HLA-DRB1 , Humanos , Interferon gama/sangue , Interleucina-18/sangue , Interleucina-4/sangue , Interleucina-6/sangue , Interleucina-8/sangue , Japão , Masculino , Receptores de Interleucina-2/sangue , Receptores do Fator de Necrose Tumoral/sangue , Receptores Tipo II do Fator de Necrose Tumoral , Doença de Still de Início Tardio/genética , Fator de Necrose Tumoral alfa/metabolismo
11.
Mod Rheumatol ; 11(2): 91-102, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24383684

RESUMO

Abstract Systemic autoimmune diseases that are resistant to conventional treatment cause considerable morbidity and mortality. Although aggressive new approaches to treating autoimmune diseases have been developed over the past decade, there are still patients with a severe, progressive, and life-threatening course. Based on animal studies and experience in the treatment of hematological disorders with preexisting autoimmune disease, hematopoietic stem cell transplantation has been proposed for the treatment of severe autoimmune diseases. Immunoablation and subsequent autologous peripheral blood stem cell transplantation using CD34(+) hematopoietic cells with T cell depletion have been used for selected severe autoimmune diseases at many institutes in Australia, Europe, and the United States. However, it is necessary to assess the efficacy and safety of this therapy compared with conventional and other newly emerging therapies.

14.
Nihon Rinsho Meneki Gakkai Kaishi ; 23(1): 30-6, 2000 Feb.
Artigo em Japonês | MEDLINE | ID: mdl-10771570

RESUMO

We report a case with rheumatoid arthritis and hypersensitivity pneumonitis. A 66-year-old female was admitted to our hospital because of fever, cough, and progressive dyspnea on October 10, 1997. She had a history of rheumatoid arthritis from 1987 and was treated with cyclophosphamide when she developed pulmonary symptoms in September 1997. On admission arthritis was subsided. Fine crackles on ausculation of lung, hypoxia, ground-glass appearance on chest X-ray were detected. The computed tomography of the chest disclosed diffuse interstitial shadow with patchy destruction of alveolar structures. Bronchoalveolar lavage demonstrated an increase in lymphocytes with predominance of suppressor-cytotoxic T cell subset (CD 8+). The histopathological examination of transbronchial lung biopsy showed interstitial inflammation with marked predominance of lymphocyte with intraalveolar exudate. Her condition got better and she discharged without definitive diagnosis and treatment for her respiratory symptoms. Eight hours after she went back home, she suddenly presented high fever and cough and gradually developed dyspnea. She was readmitted 5 days after the previous discharge. Although no specific precipitin antibody against various microorganisms was detected in her sera, the diagnosis of hypersensitivity pneumonitis was made. Thirty mg per day of prednisolone was resolved her symptoms promptly. There was no reported case with hypersensitivity pneumonitis and rheumatoid arthritis of other collagen diseases. The clinical course that arthritis and pulmonary symptoms appeared alternatively is of considerable interest to investigate for the pathogenesis of these two immune disorders.


Assuntos
Alveolite Alérgica Extrínseca/complicações , Artrite Reumatoide/complicações , Idoso , Feminino , Humanos
15.
Clin Exp Rheumatol ; 18(1): 86-8, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10728451

RESUMO

This report describes the case of a 47-year old man who developed myositis in association with hepatitis B surface antigen-positive hepatitis. Interestingly, the myositis repeatedly worsened 2 months after the exacerbation of hepatitis in this case, suggesting a close association between hepatitis B infection and myositis. The dose of prednisolone was increased twice in order to treat the exacerbating myositis, resulting in improvement of the muscle symptoms, but the patient eventually died of liver failure. Only 5 other myositis patients with hepatitis B antigenemia have been reported in the literature. We review these cases of the association between hepatitis B infection and myositis.


Assuntos
Hepatite B , Polimiosite/virologia , Anti-Inflamatórios/uso terapêutico , Evolução Fatal , Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/análise , Humanos , Masculino , Pessoa de Meia-Idade , Polimiosite/tratamento farmacológico , Prednisolona/uso terapêutico
18.
J Biol Chem ; 274(50): 35933-7, 1999 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-10585480

RESUMO

Vinexin, a novel protein that plays a key role in cell spreading and cytoskeletal organization, contains three SH3 domains and binds to vinculin through its first and second SH3 domains. We show here that the third SH3 domain binds to Sos, a guanine nucleotide exchange factor for Ras and Rac, both in vitro and in vivo. Point mutations in the third SH3 domain abolished the vinexin-Sos interaction. Stimulation of NIH/3T3 cells with serum, epidermal growth factor (EGF), or platelet-derived growth factor (PDGF) decreased the electrophoretic mobility of Sos and concomitantly inhibited formation of the vinexin-Sos complex. Phosphatase treatment of lysates restored the binding of Sos to vinexin, suggesting that signaling from serum, EGF, or PDGF regulates the vinexin-Sos complex through the Sos phosphorylation. To evaluate the function of vinexin downstream of growth factors, we examined the effects of wild-type and mutant vinexin expression on extracellular signal-regulated kinase (Erk) and c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) activation in response to EGF. Exogenous expression of vinexin beta in NIH/3T3 cells enhanced JNK/SAPK activation but did not affect Erk activation. Moreover mutations in the third SH3 domain abolished EGF activation of JNK/SAPK in a dominant-negative fashion, whereas they slightly stimulated Erk. Together these results suggest that vinexin can selectively modulate EGF-induced signal transduction pathways leading to JNK/SAPK kinase activation.


Assuntos
Fator de Crescimento Epidérmico/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Musculares/metabolismo , Proteínas Son Of Sevenless/metabolismo , Células 3T3 , Animais , Cromatografia de Afinidade , Proteínas Quinases JNK Ativadas por Mitógeno , Cinética , Camundongos , Proteínas Musculares/química , Proteínas Musculares/isolamento & purificação , Fosforilação , Fator de Crescimento Derivado de Plaquetas/farmacologia , Mutação Puntual , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais , Proteínas Son Of Sevenless/química , Proteínas Son Of Sevenless/isolamento & purificação , Transfecção , Domínios de Homologia de src
19.
J Immunol ; 163(11): 6269-74, 1999 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-10570320

RESUMO

Proteolytic cleavage by caspases is the central event in cells undergoing apoptosis. Cleaved proteins are often targeted by autoantibodies, suggesting that the cleavage of self Ags enhances immunogenicity and is prone to induce an autoimmune response. We found autoantibodies that immunoprecipitated a 140-kDa RNA-associated protein, provisionally designated Pa, in 11 of 350 patient sera that were positive for antinuclear Abs in an immunofluorescence test. The Pa protein gave rise to three fragments with m.w. ranging from 120-130 kDa during anti-Fas-activated apoptosis. Pure caspase-3 cleaved the Pa protein into a 130-kDa fragment corresponding to the largest of these three products. Peptide sequence analysis of a tryptic digest from immunoaffinity-purified Pa showed 100% identity to human RNA helicase A (RHA). The identity of Pa with RHA was further confirmed by immunoblotting with rabbit anti-RHA Ab using anti-Pa immunoprecipitates as substrates. All 10 anti-RHA-positive patients who were clinically analyzed were diagnosed as having systemic lupus erythematosus, and 7 of them had lupus nephritis. RHA is a multifunctional protein with roles in cellular RNA synthesis and processing. Inactivation of RHA by cleavage may be an important part of the process leading to programmed cell death. The cleaved RHA fragments that are produced during apoptosis may trigger an autoimmune response in systemic lupus erythematosus.


Assuntos
Apoptose , Autoantígenos/imunologia , Caspases/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , RNA Helicases/imunologia , Sequência de Aminoácidos , Autoantígenos/metabolismo , Caspase 3 , RNA Helicases DEAD-box , Células HeLa , Humanos , Dados de Sequência Molecular , Proteínas de Neoplasias , Fragmentos de Peptídeos/química , RNA Helicases/metabolismo , Análise de Sequência de Proteína
20.
Nihon Rinsho ; 57 Suppl: 403-5, 1999 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-10635867
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