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1.
J Diabetes Investig ; 14(10): 1202-1208, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37357565

RESUMO

AIMS/INTRODUCTION: Polypharmacy in diabetes patients is related to worse clinical outcomes. The aim of this study was to evaluate the usefulness of our countermeasure for polypharmacy, which combines a pharmacist check followed by a multidisciplinary team review in diabetic patients with polypharmacy. METHODS: A single-center, retrospective observational study was conducted at Gifu University Hospital. Study participants included diabetic patients taking six or more drugs on admission to the diabetes ward between July 2021 and June 2022. Drugs which were discontinued by the present countermeasure were examined, and the number of drugs being taken by each patient was compared between admission and discharge. RESULTS: 102 of 308 patients were taking six or more drugs on admission. The drugs being taken by these patients were evaluated by pharmacists using a checklist for polypharmacy. Eighty-four drugs which were evaluated as inappropriate or potentially inappropriate medications by pharmacists were discontinued following the multidisciplinary team review. The median and mean number of drugs taken by the 102 patients significantly decreased from 9.0 (IQR: 8-12) and 9.26 ± 2.64 on admission to 9.0 (IQR: 6-10) and 8.42 ± 2.95 on discharge (P = 0.0002). We followed up with these patients after discontinuation of the drugs and confirmed that their clinical status had not deteriorated. CONCLUSION: The present countermeasure for polypharmacy, which combines a pharmacist check based on a checklist for evaluating polypharmacy followed by a multidisciplinary team review, was useful for reducing the number of inappropriate or potentially inappropriate medications taken by diabetes patients with polypharmacy.


Assuntos
Diabetes Mellitus , Prescrição Inadequada , Humanos , Polimedicação , Estudos Prospectivos , Diabetes Mellitus/tratamento farmacológico , Equipe de Assistência ao Paciente
2.
Am J Cardiol ; 189: 56-60, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36508763

RESUMO

The redox state of human serum albumin (HSA) is reported to be an oxidative stress biomarker; however, its clinical use in cardiac disease has not yet been examined. This study aimed to investigate the relation between the redox state of HSA and exercise capacity, which is a robust prognostic factor, in patients with cardiovascular disease. This cross-sectional study included outpatients with cardiac disease. Exercise capacity was assessed by peak oxygen consumption (peakVO2) measured using symptom-limited cardiopulmonary exercise testing. The high-performance liquid chromatography postcolumn bromocresol green method was used to part HSA into human nonmercaptalbumin (oxidized form) and human mercaptalbumin (HMA, reduced form). The fraction of human mercaptalbumin found in HSA (f[HMA]) was calculated as an indicator of the redox state of HSA. The association between peakVO2 and f(HMA) was examined using the Spearman correlation coefficient and multivariate linear regression analysis. A total of 70 patients were included (median age 76 years; 44 men; median peakVO2 15.5 ml/kg/min). The f(HMA) was positively correlated with peakVO2 (r = 0.38, p <0.01). Even after controlling for potential confounders, this association remained in the multivariate linear regression analysis (standardized beta = 0.24, p <0.05). We found a positive association between f(HMA) and peakVO2, independent of potential confounders in patients with cardiac disease, suggesting that f(HMA) may be a novel biomarker related to exercise capacity in cardiac disease. Longitudinal studies are required to further examine the prognostic capability of f(HMA), the responsiveness to clinical intervention, and the association between f(HMA) and cardiac disease.


Assuntos
Tolerância ao Exercício , Cardiopatias , Masculino , Humanos , Idoso , Estudos Transversais , Albumina Sérica Humana/metabolismo , Oxirredução , Biomarcadores
3.
Biol Pharm Bull ; 45(10): 1510-1517, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35922913

RESUMO

Royal jelly (RJ) has beneficial effects on human health, and some of these effects are reported to be the result of its estrogenic activity; however, chemicals with estrogenic activities may disrupt physiological estrogen signaling leading to adverse effects on human health. Thus, clarification of the mode of action of RJ is needed. Here, we investigated whether the estrogen-like actions of RJ are induced via estrogen receptors (ERs)-mediated genomic actions by using an in vitro reporter assay in human choriocarcinoma JEG3 cells and an estrogen-responsive reporter (E-Rep) mouse line that can be used to sensitively detect transactivation of ERs in multiple organs simultaneously. In the in vitro reporter assay, ERs-dependent transcriptional activity was significantly increased by 17ß-estradiol (E2) treatment at concentrations of 1 nM and above, confirming that the assay was highly responsive to estrogen; however, RJ did not exhibit any agonist activity via either the α or ß form of ER. Similarly, in E-Rep mice, E2 showed significant ERs-dependent genomic action in 17 tissue types including uterus and mammary gland, whereas RJ did not. Thus, unlike endocrine-disrupting chemicals, the estrogen-like activity of RJ is unlikely to be due to genomic actions via ERs.


Assuntos
Estrogênios , Receptores de Estrogênio , Potenciais de Ação , Animais , Linhagem Celular Tumoral , Estradiol/metabolismo , Receptor alfa de Estrogênio , Estrogênios/farmacologia , Ácidos Graxos , Feminino , Genômica , Humanos , Camundongos , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Transdução de Sinais
4.
J Clin Pharm Ther ; 46(3): 794-799, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33393716

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Ifosfamide, an alkylating agent, is widely used in the treatment of malignant diseases. However, these treatments are often limited due to the incidence of neuropsychiatric symptoms such as delirium, seizures, hallucinations and agitation. In this study, we examined risk factors for neuropsychiatric symptoms in patients receiving ifosfamide-based chemotherapy. METHODS: The study cases were patients with cancer receiving ifosfamide-based chemotherapy between April 2007 and March 2018. Risk analysis for ifosfamide-related neuropsychiatric symptoms was determined by time-dependent Cox proportional hazard regression analysis. RESULTS AND DISCUSSION: Of 183 eligible patients, 32 patients (17.5%) experienced ifosfamide-related neuropsychiatric symptoms. Time-dependent Cox proportional hazard model showed that the albumin-bilirubin (ALBI) score was significantly correlated with the incidence of ifosfamide-related neuropsychiatric symptoms (hazard ratio [HR] =1.45, 95% confidence interval [CI] = 1.05-2.01, p = 0.025). Additionally, there were correlations between the predicted risk of neuropsychiatric symptoms and ifosfamide-dose per cycle (HR =0.51, 95% CI = 0.27-0.94, p = 0.030) and creatinine clearance (Ccr) (HR = 0.53, 95% CI = 0.28-1.00, p = 0.050). In contrast, neither serum albumin nor total bilirubin was a significant risk factor for neuropsychiatric symptoms. WHAT IS NEW AND CONCLUSION: These findings indicate that ALBI score may be a useful biomarker for predicting neuropsychiatric symptoms in patients receiving ifosfamide-based chemotherapy.


Assuntos
Antineoplásicos Alquilantes/efeitos adversos , Bilirrubina/análise , Ifosfamida/efeitos adversos , Transtornos Mentais/induzido quimicamente , Albumina Sérica/análise , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Creatina/sangue , Feminino , Humanos , Testes de Função Renal , Testes de Função Hepática , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Adulto Jovem
5.
Nagoya J Med Sci ; 82(1): 129-134, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32273641

RESUMO

We herein report the long-term changes in cardiac function and pathological findings after successful explantation of a left ventricular assist device in a 42-year-old patient with anthracycline-induced cardiomyopathy with reworsening heart failure. Endomyocardial biopsy samples revealed that the cardiomyocyte diameter decreased and collagen volume fraction increased just after left ventricular assist device explantation. The collagen volume fraction decreased after 6 months, despite preserved systolic function. At 5 years after left ventricular assist device explantation, the systolic function markedly decreased and cardiomyocyte diameter increased. Pathological changes of the myocardium may enable the identification of cardiac dysfunction prior to echocardiographic changes in patients with reworsening heart failure after left ventricular assist device explantation.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Cardiomiopatias/induzido quimicamente , Daunorrubicina/efeitos adversos , Remoção de Dispositivo/efeitos adversos , Coração Auxiliar , Idarubicina/efeitos adversos , Leucemia Promielocítica Aguda/tratamento farmacológico , Miocárdio/patologia , Adulto , Cardiomiopatias/patologia , Cardiomiopatias/fisiopatologia , Cardiomiopatias/terapia , Cardiotoxicidade , Progressão da Doença , Feminino , Fibrose , Humanos , Fatores de Tempo , Função Ventricular Esquerda
6.
Int J Clin Pract ; 74(4): e13464, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31830345

RESUMO

BACKGROUND: The increasing cost of anticancer drugs is now being recognised as a global problem, and measures against drug wastage are among the most important cost containment strategies for anticancer drugs. OBJECTIVE: When blood examination results or changes to a patient's condition necessitate dose reduction or discontinuation of anticancer drugs after their preparation, the compounded anticancer drugs are discarded. To reduce anticancer drug wastage after preparation, we developed a protocol that set the eligibility, start of treatment, dose reduction and discontinuation criteria for injectable anticancer drugs and assessed the effect of pharmacists' checks of these criteria based on the present protocol prior to preparation of injectable anticancer drugs. METHOD: Observations before and after introduction of the protocol were conducted at Gifu University Hospital. We recorded the number, type and cost of anticancer drugs discarded after preparation and the reason for discarding these drugs in our dedicated database. RESULTS: Checking the criteria for anticancer drug administration before preparation significantly reduced the rate at which anticancer drugs within a chemotherapy cycle were discarded after preparation compared with that prior to the protocol's introduction (0.367% [18/4909] vs 0.032% [2/6248], P < .001). Additionally, the total cost of anticancer drugs discarded after preparation was reduced from JPY 2 041 786 (USD 18 562) to JPY 398 414 (USD 3622). CONCLUSION: Pharmacists' checks of the eligibility, start of treatment, dose reduction and discontinuation criteria for anticancer drugs based on the present protocol prior to preparation of injectable anticancer drugs was useful for reducing drug wastage after preparation.


Assuntos
Antineoplásicos/administração & dosagem , Antineoplásicos/economia , Neoplasias/tratamento farmacológico , Serviço de Farmácia Hospitalar/métodos , Adulto , Idoso , Redução de Custos , Composição de Medicamentos , Custos de Medicamentos , Humanos , Conduta do Tratamento Medicamentoso , Pessoa de Meia-Idade , Farmacêuticos , Papel Profissional , Estudos Retrospectivos , Adulto Jovem
7.
Cancer Chemother Pharmacol ; 84(5): 1097-1105, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31502115

RESUMO

PURPOSE: Ifosfamide is extensively used to treat several malignant conditions. Administration of ifosfamide can cause encephalopathy and other neurotoxic effects. The aim of this study was to obtain novel information on the onset profiles of ifosfamide-induced encephalopathy (IIE) considering other associated clinical factors using the US Food and Drug Administration Adverse Event Reporting System (FAERS) and the Japanese Adverse Drug Event Report (JADER) databases. METHODS: We analyzed the reports of encephalopathy between 2004 and 2018 from the FAERS and JADER databases. To define IIE, we used the Medical Dictionary for Regulatory Activities (MedDRA) preferred terms and standardized queries. The reporting odds ratios (ROR) at 95% confidence interval (CI) was used to detect the signal for IIE and adjusted for covariates using a multivariate logistic regression technique. We evaluated the time-to-onset profile of IIE and used the association rule mining technique to discover undetected associations, such as potential risk factors. RESULTS: In the FAERS database, the ROR (CI) for encephalopathy (preferred term, PT) and encephalopathy (standardized MedDRA queries, SMQ) was 56.58 (51.69-61.93) and 1.57 (1.48-1.67), respectively. In the JADER database, the ROR (95% CI) for encephalopathy (PT) and encephalopathy (SMQ) was 13.54 (9.91-18.50) and 1.24 (1.01-1.53), respectively. The multivariate logistic regression analysis showed a significant contribution in IIE signal in the ≥ 60 year group (p = 0.00094; vs. < 60 year group) and ≥ 2000 mg/m2 dosage group (p = 0.00045; vs. < 2000 mg/m2 dosage group). The association rules of {ifosfamide, aprepitant} → {encephalopathy (SMQ)} demonstrated high lift values. The average dose of ifosfamide in patients with encephalopathy (PT) and without encephalopathy (PT) was 2022.8 ± 592.8 (mean ± standard deviation) and 1568.5 ± 703.2 mg/m2, respectively (p < 0.05). Encephalopathy within the first 7 days of ifosfamide administration was 94.1% for encephalopathy (PT) and 87.7% for encephalopathy (SMQ), respectively. CONCLUSIONS: The present analysis demonstrated that the incidence of encephalopathy with ifosfamide should be closely monitored for a short onset (within 7 days). The patients who are administered a high dose of ifosfamide or co-administrated aprepitant should be carefully monitored for the development of encephalopathy.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/estatística & dados numéricos , Antineoplásicos Alquilantes/efeitos adversos , Encefalopatias/induzido quimicamente , Ifosfamida/efeitos adversos , Adolescente , Adulto , Antineoplásicos Alquilantes/administração & dosagem , Encefalopatias/epidemiologia , Criança , Pré-Escolar , Bases de Dados Factuais , Relação Dose-Resposta a Droga , Feminino , Humanos , Ifosfamida/administração & dosagem , Incidência , Lactente , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Fatores de Tempo , Estados Unidos , United States Food and Drug Administration , Adulto Jovem
8.
Neurobiol Dis ; 118: 142-154, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30026035

RESUMO

Astrocyte-microglia communication influences the onset and progression of central nervous system (CNS) disorders. In this study, we determined how chronic inflammation by activated astrocytes affected and regulated CNS functions in Sandhoff disease (SD), a CNS lysosomal storage disorder. SD triggers intense CNS inflammation such as microglial activation and astrogliosis. It is caused by mutation of the HEXB gene, which reduces ß-hexosaminidase (Hex) enzymatic activity in lysosomes, leading to accumulation of the substrate GM2 ganglioside in neuronal cells. Hexb-/- mice display a phenotype similar to human patients that suffer from chronic inflammation characterized by activation of astrocytes and microglia. In Hexb-/- mice, tremors and loss of muscle coordination begins at ~12 weeks. Interestingly, we found that reactive astrocytes expressed adenosine A2A receptor in the cerebral cortices of Hexb-/- mice at the later inflammatory phase. In cultured astrocytes, expression of A2A receptor could be induced by astrocyte defined medium, and then the activation of the A2A receptor induced ccl2 expression. In Hexb-/- mice, inhibition of the A2A receptor antagonized by istradefylline decreased the number of activated microglial cells and inflammatory cytokines/chemokines at 13 weeks. Thus, the astrocytic A2A receptor is an important sensor that regulates microglial activation in the late phase of inflammation.


Assuntos
Antagonistas do Receptor A2 de Adenosina/farmacologia , Astrócitos/metabolismo , Modelos Animais de Doenças , Microglia/metabolismo , Receptor A2A de Adenosina/metabolismo , Doença de Sandhoff/metabolismo , Antagonistas do Receptor A2 de Adenosina/uso terapêutico , Animais , Astrócitos/efeitos dos fármacos , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/efeitos dos fármacos , Purinas/farmacologia , Purinas/uso terapêutico , Doença de Sandhoff/tratamento farmacológico , Doença de Sandhoff/genética
9.
J Vet Med Sci ; 73(5): 609-13, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21187684

RESUMO

In the present study, group-specific antigen VP7 of bluetongue virus (BTV) serotype 21 isolated from cattle in Tochigi prefecture in Japan in 1994 was characterized by sequencing and expression. Gene was amplified from cDNA synthesized on viral dsRNA using reverse-transcriptase-PCR. Nucleotide sequence of this isolate showed high similarity with other published BTV VP7 sequences. Full-length and C-terminal truncated forms of VP7 were expressed in insect cells by a baculovirus gene expression system under control of the viral polyhedrin promoter. Expression of full-length recombinant VP7 was confirmed by immunoprecipitation with VP7 specific monoclonal antibody (8A3B.6, ATCC). Recombinant proteins expressed with or without 6x His-tag showed good expression levels in TN5 cells and reacted well with the monoclonal antibody in the indirect ELISA. However C-terminal truncated VP7 with His-tag failed to react with this monoclonal antibody, while poor antigenicity was evident when it was reacted with infected bovine serum. Reduced antigenicity of the latter suggested that C-terminal truncation affects 8A3B.6 epitope construction probably via inhibition of VP7 trimer structure formation.


Assuntos
Vírus Bluetongue/metabolismo , Bluetongue/virologia , Doenças dos Bovinos/virologia , Regulação Viral da Expressão Gênica/fisiologia , Proteínas do Core Viral/metabolismo , Animais , Antígenos Virais/genética , Antígenos Virais/metabolismo , Bluetongue/epidemiologia , Vírus Bluetongue/classificação , Vírus Bluetongue/genética , Vírus Bluetongue/imunologia , Bovinos , Doenças dos Bovinos/epidemiologia , Linhagem Celular , Cricetinae , Japão/epidemiologia , Sorotipagem , Proteínas do Core Viral/genética
10.
J Biochem ; 146(4): 541-7, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19605464

RESUMO

Protein-tyrosine phosphatase 1B (PTP1B) is a major regulator of insulin sensitivity. We have described a novel action of PTP1B in the induction of sterol regulatory element-binding protein-1 (SREBP-1) gene expression through activation of protein phosphatase 2A (PP2A). PTP1B is anchored to the endoplasmic reticulum membrane via its C-terminal tail. We have previously reported that membrane localization of PTP1B is essential for PP2A activation, which is crucial for enhancing SREBP-1 gene expression in in vitro experiments. In this study, we further investigated the physiological importance of membrane localization of PTP1B in vivo. We found that transient liver-specific overexpression of wild-type PTP1B (PTP1B-WT) using adenovirus-mediated gene transfer was associated with hypertriglyceridaemia and enhanced hepatic SREBP-1 gene expression in mice. However, overexpression of the C-terminal truncated PTP1B (PTP1BDeltaCT) failed to increase hepatic SREBP-1 expression or serum triglyceride levels, despite causing insulin resistance. Our results indicate that activation of PTP1B in the liver could induce hypertriglyceridaemia and that anchoring of PTP1B to the membrane is crucial for its action.


Assuntos
Membrana Celular/enzimologia , Hipertrigliceridemia/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Animais , Membrana Celular/química , Membrana Celular/metabolismo , Retículo Endoplasmático/química , Retículo Endoplasmático/enzimologia , Retículo Endoplasmático/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos CBA , Proteína Fosfatase 2/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/química , Ratos , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo
11.
Exp Hematol ; 34(7): 905-13, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16797418

RESUMO

OBJECTIVE: Monoclonal antibodies (mAbs) against CD34 are widely used for purification of CD34+ hematopoietic as well as nonhematopoietic stem/progenitor cells. We produced mAbs against bovine CD34 (boCD34) to facilitate the study of hematopoiesis in cattle. METHODS: MAbs were produced by immunizing BALB/c mice with BALB/3T3 cells transfected with boCD34 cDNA. Staining of bone marrow mononuclear cells (BMMNCs) from 10 newborn Holstein calves with the mAbs was examined by flow cytometry. The nucleotide sequence of the coding region for boCD34 in each calf was determined after amplification of the cDNA by reverse-transcription polymerase chain reaction (RT-PCR). BoCD34 fusion proteins, each representing one of the boCD34 alleles found to exist in the calves, were expressed in HeLa cells by DNA transfection, and the staining of these proteins with the mAbs was assessed. RESULTS: One mAb, N21, stained relatively high percentages of BMMNCs from 4 calves but failed to stain those from the other calves. RT-PCR analysis revealed single-nucleotide polymorphisms within the coding region, 3 of which led to amino-acid substitutions. A CD34 mutation experiment indicated that mAb N21 bound to a boCD34 allele with tryptophan at amino acid 167 but not to that with arginine. CONCLUSION: By using mAb N21 as an allelic cell marker, it would be feasible to detect and isolate boCD34+ cell species derived from N21+ donors in N21- recipients following allogeneic in utero transplantation; this would make cattle potentially useful as large animal models with a unique experimental advantage.


Assuntos
Anticorpos Monoclonais/imunologia , Antígenos CD34/genética , Antígenos CD34/imunologia , Polimorfismo Genético , Sequência de Aminoácidos , Animais , Sequência de Bases , Bovinos , Primers do DNA , Citometria de Fluxo , Células HeLa , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa
12.
J Immunol ; 174(6): 3626-32, 2005 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-15749900

RESUMO

Stem cell factor (SCF), which is well known as a cytokine capable of amplifying development and functions of mast cells, is mainly released from fibroblasts in the peripheral tissue. To investigate whether SCF controlled chemotactic migration of mast cells induced by IgE-specific Ag, murine bone marrow-derived cultured mast cells (BMCMC) and human cord blood-derived cultured mast cells (HuCMC) were preincubated with SCF. Although BMCMC and HuCMC sensitized with IgE directly moved toward specific Ag, preincubation for even 1 h with an optimal dose of SCF suppressed the IgE-mediated chemotactic movement. No or little inhibitory effect of SCF was detected in BMCMC derived from c-kit receptor-defect WBB6F1-W/Wv mice. In contrast, preincubation of BMCMC and HuCMC with SCF enhanced beta-hexosaminidase release and Ca2+ mobilization in response to Ag after sensitization with IgE. Using the real-time record of chemotactic migration, BMCMC preincubated with SCF manifested motionless without degranulation. These results suggest that locally produced SCF may have an inhibitory effect on chemotaxis of mast cells, contributing to their accumulation and enhancement of functions at the peripheral site in allergic and nonallergic conditions.


Assuntos
Quimiotaxia/efeitos dos fármacos , Imunoglobulina E/metabolismo , Mastócitos/efeitos dos fármacos , Mastócitos/imunologia , Fator de Células-Tronco/farmacologia , Animais , Antígenos/administração & dosagem , Sinalização do Cálcio/efeitos dos fármacos , Dinitrobenzenos/imunologia , Feminino , Humanos , Imunossupressores/farmacologia , Técnicas In Vitro , Recém-Nascido , Masculino , Mastócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Fator de Crescimento Neural/farmacologia , Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/metabolismo , Ratos , Ratos Endogâmicos F344 , Receptores de IgE/metabolismo , Proteínas Recombinantes/farmacologia , beta-N-Acetil-Hexosaminidases/biossíntese
13.
J Biol Chem ; 278(44): 43095-101, 2003 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-12941932

RESUMO

Like hyperglycemia, postprandial (diet-induced) hypertriglyceridemia is thought to play crucial roles in the pathogenesis of insulin resistant/metabolic syndrome. Sterol regulatory element-binding protein-1 (SREBP-1) is a key transcription factor to induce postprandial hypertriglyceridemia. We found that insulin-resistant rats fed a diet high in fructose showed an increased proteintyrosine phosphatase 1B (PTP1B) content with strong expression of SREBP-1 mRNA in the liver. To clarify the association of PTP1B with SREBP-1 gene expression, we overexpressed PTP1B in rat hepatocytes, which led to increased mRNA content and promoter activity of SREBP-1a and -1c, resulting in the increased mRNA expression of fatty-acid synthase, one of the SREBP-1-responsive lipogenic genes. Because PTP1B overexpression increased phosphatase 2A (PP2A) activity, we inhibited PP2A activity by expression of its selective inhibitor, SV40 small T antigen and found that this normalized the PTP1B-enhanced SREBP-1a and -1c mRNA expressions through activation of the Sp1 site. These results indicate that PTP1B may regulate gene expression of SREBP-1 via enhancement of PP2A activity, thus mediating hepatic lipogenesis and postprandial hypertriglyceridemia. We demonstrate here a unique serial activation of the PTP1B-PP2A axis as a novel mechanism for the regulation of gene expression in the biosynthesis of triglyceride.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Fígado/metabolismo , Proteínas Tirosina Fosfatases/fisiologia , Fatores de Transcrição , Adenoviridae/genética , Animais , Northern Blotting , Western Blotting , Células Cultivadas , DNA Complementar/metabolismo , Frutose/metabolismo , Genes Reporter , Hepatócitos/metabolismo , Insulina/metabolismo , Resistência à Insulina , Luciferases/metabolismo , Modelos Biológicos , Testes de Precipitina , Regiões Promotoras Genéticas , Proteína Fosfatase 2 , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Proteínas Tirosina Fosfatases/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Ribonucleases/metabolismo , Transdução de Sinais , Fator de Transcrição Sp1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1 , Transcrição Gênica , Triglicerídeos/metabolismo
14.
Endocrinology ; 143(12): 4563-9, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12446583

RESUMO

We investigated the effect of overexpression of protein-tyrosine phosphatase 1B (PTP1B) on insulin signaling in 3T3-L1 adipocytes. Overexpression of a wild-type PTP1B in L1 adipocytes as well as in L6 myocytes, led to a profound decrease in insulin-stimulated phosphorylation of MAPK. Even though the decrease in insulin receptor substrate protein-1 (IRS-1) phosphorylation was identical with that seen in L6 myocytes, overexpression of wild-type PTP1B in L1 adipocytes was associated with modest impairment of insulin-stimulated Akt phosphorylation in addition to a small, but significant, attenuation in insulin-stimulated glucose uptake, when compared with a phosphatase-negative mutant. Regarding the relatively small effect on Akt phosphorylation, we obtained identical results in rat 1 fibroblasts overexpressing human insulin receptor, suggesting that the higher expression levels of insulin receptor and IRS-1 might be responsible. With regard to the large effect on MAPK phosphorylation, we found that PTP1B overexpression led to the impaired phosphorylation of both IRS-1 and Shc, resulting in a decrease in their association with Grb2. Furthermore, phosphorylation of Shc stimulated by platelet-derived growth factor was also attenuated, without any change in its receptors, suggesting that PTP1B directly regulates Shc phosphorylation. These data demonstrate that PTP1B negatively regulates insulin signaling in the MAPK cascade to a much greater extent than the Akt pathway in some cell lines, especially in L1 adipocytes.


Assuntos
Adipócitos/enzimologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas Tirosina Fosfatases/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Células 3T3 , Animais , Linhagem Celular , Desoxiglucose/metabolismo , Fibroblastos/metabolismo , Expressão Gênica , Humanos , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina , Transferases Intramoleculares/metabolismo , Camundongos , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Proteínas Tirosina Fosfatases/genética , Proteínas Proto-Oncogênicas c-akt , Ratos , Receptor de Insulina/genética , Receptor de Insulina/fisiologia , Transdução de Sinais , Transfecção
15.
J Biol Chem ; 277(41): 38863-9, 2002 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-12147684

RESUMO

It is reported that 3-phosphoinositide-dependent protein kinase-1 (PDK-1) is activated in a phosphatidylinositol 3,4,5-trisphosphate-dependent manner and phosphorylates Akt, p70S6 kinase, and atypical protein kinase C (PKC), but its function on insulin signaling is still unclear. We cloned a full-length pdk-1 cDNA from a human brain cDNA library, and the adenovirus to overexpress wild type PDK-1 (PDK-1WT) or membrane-targeted PDK-1 (PDK-1CAAX) was constructed. Overexpressed PDK-1WT existed mainly at cytosol, and PDK-1CAAX was located at the plasma membrane. In 3T3-L1 adipocytes, insulin induced mobility shift of PDK-1 protein, but overexpressed PDK-1WT and CAAX were shifted at the basal state. Insulin stimulated tyrosine phosphorylation of PDK-1WT, but PDK-1CAAX was already tyrosine-phosphorylated at the basal state. Overexpression of PDK-1WT led to a full activation of PKC zeta/lambda without insulin stimulation but showed only the minimum effects to stimulate phosphorylation of Akt and GSK-3. In contrast, the overexpression of PDK-1CAAX caused phosphorylation of Akt and GSK-3 more strongly without insulin stimulation. However, PDK-1CAAX did not affect 2-deoxyglucose uptake and inhibited glycogen synthesis, surprisingly. Finally, PDK-1CAAX expression inhibited insulin-induced ERK1/2 phosphorylation in a dose-dependent manner. Taken together, the translocation of PDK-1 from cytosol to the plasma membrane is critical for Akt and GSK-3 activation. On the other hand, only atypical PKC and Akt activation was insufficient for stimulation of glucose transport, and constitutive activation of Akt-GSK-3 pathway may inhibit glycogen synthesis and MAPK cascade in 3T3-L1 adipocytes.


Assuntos
Adipócitos/metabolismo , Transporte Biológico/fisiologia , Glucose/metabolismo , Glicogênio/biossíntese , Proteínas Musculares , Proteína Quinase C/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Quinases Dependentes de 3-Fosfoinositídeo , Células 3T3 , Adipócitos/efeitos dos fármacos , Animais , Encéfalo/fisiologia , Glucose/análogos & derivados , Transportador de Glucose Tipo 4 , Hepatócitos/citologia , Humanos , Insulina/farmacologia , Isoenzimas/metabolismo , Masculino , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Dados de Sequência Molecular , Proteínas de Transporte de Monossacarídeos/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-akt , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/fisiologia
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