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1.
PLoS One ; 19(5): e0304389, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38820295

RESUMO

AIM: Malnutrition in pregnant women significantly affects both mother and child health. This research aims to identify the best machine learning (ML) techniques for predicting the nutritional status of pregnant women in Bangladesh and detect the most essential features based on the best-performed algorithm. METHODS: This study used retrospective cross-sectional data from the Bangladeshi Demographic and Health Survey 2017-18. Different feature transformations and machine learning classifiers were applied to find the best transformation and classification model. RESULTS: This investigation found that robust scaling outperformed all feature transformation methods. The result shows that the Random Forest algorithm with robust scaling outperforms all other machine learning algorithms with 74.75% accuracy, 57.91% kappa statistics, 73.36% precision, 73.08% recall, and 73.09% f1 score. In addition, the Random Forest algorithm had the highest precision (76.76%) and f1 score (71.71%) for predicting the underweight class, as well as an expected precision of 82.01% and f1 score of 83.78% for the overweight/obese class when compared to other algorithms with a robust scaling method. The respondent's age, wealth index, region, husband's education level, husband's age, and occupation were crucial features for predicting the nutritional status of pregnant women in Bangladesh. CONCLUSION: The proposed classifier could help predict the expected outcome and reduce the burden of malnutrition among pregnant women in Bangladesh.


Assuntos
Aprendizado de Máquina , Estado Nutricional , Humanos , Feminino , Bangladesh/epidemiologia , Gravidez , Adulto , Estudos Transversais , Estudos Retrospectivos , Adulto Jovem , Inquéritos Epidemiológicos , Adolescente , Algoritmos , Desnutrição/epidemiologia , Desnutrição/diagnóstico , Gestantes , Pessoa de Meia-Idade
2.
Curr Opin Pharmacol ; 11(6): 725-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22051884

RESUMO

Phosphodiesterase-3 (PDE3) is a major cAMP-hydrolyzing PDE in vascular smooth muscle cells (VSMCs) and oocytes. The exact role and contribution of the two PDE3 isoforms, PDE3A and PDE3B, in VSMC growth regulation and oocyte maturation was examined using PDE3A (3A) and PDE3B (3B) knockout (KO) mouse models. PDE3A-deficient VSMCs exhibit marked reduction in mitogen-induced cell growth due to cell cycle arrest at G0-G1 phase, which resulted from dysregulation of cAMP/protein kinase A (PKA)-activated and mitogen-activated protein kinase (MAPK)-signaling pathways, as well as from alterations in key cell cycle regulatory proteins. Similarly, PDE3A-deficient oocytes exhibit cell cycle arrest at G2/M phase because increased cAMP/PKA signaling in KO oocytes most likely inhibits Cdc25B-catalyzed dephosphorylation/activation of Cdc2 (maturation promoting factor (MPF)), a key regulator of G2/M transition.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Ciclo Celular , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/metabolismo , Infertilidade Feminina/tratamento farmacológico , Músculo Liso Vascular/enzimologia , Oócitos/enzimologia , Inibidores da Fosfodiesterase 3/farmacologia , Animais , Doenças Cardiovasculares/enzimologia , Doenças Cardiovasculares/metabolismo , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , AMP Cíclico/antagonistas & inibidores , AMP Cíclico/fisiologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/química , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/genética , Feminino , Humanos , Infertilidade Feminina/enzimologia , Infertilidade Feminina/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Mesotelina , Camundongos , Camundongos Knockout , Terapia de Alvo Molecular , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Oogênese/efeitos dos fármacos , Inibidores da Fosfodiesterase 3/uso terapêutico , Transdução de Sinais/efeitos dos fármacos
3.
J Biol Chem ; 286(29): 26238-49, 2011 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-21632535

RESUMO

Cyclic nucleotide phosphodiesterase 3 (PDE3) is an important regulator of cyclic adenosine monophosphate (cAMP) signaling within the cardiovascular system. In this study, we examined the role of PDE3A and PDE3B isoforms in regulation of growth of cultured vascular smooth muscle cells (VSMCs) and the mechanisms by which they may affect signaling pathways that mediate mitogen-induced VSMC proliferation. Serum- and PDGF-induced DNA synthesis in VSMCs grown from aortas of PDE3A-deficient (3A-KO) mice was markedly less than that in VSMCs from PDE3A wild type (3A-WT) and PDE3B-deficient (3B-KO) mice. The reduced growth response was accompanied by significantly less phosphorylation of extracellular signal-regulated kinase (ERK) in 3A-KO VSMCs, most likely due to a combination of greater site-specific inhibitory phosphorylation of Raf-1(Ser-²59) by protein kinase A (PKA) and enhanced dephosphorylation of ERKs due to elevated mitogen-activated protein kinase phosphatase 1 (MKP-1). Furthermore, 3A-KO VSMCs, compared with 3A-WT, exhibited higher basal PKA activity and cAMP response element-binding protein (CREB) phosphorylation, higher levels of p53 and p53 phosphorylation, and elevated p21 protein together with lower levels of Cyclin-D1 and retinoblastoma (Rb) protein and Rb phosphorylation. Adenoviral overexpression of inactive CREB partially restored growth effects of serum in 3A-KO VSMCs. In contrast, exposure of 3A-WT VSMCs to VP16 CREB (active CREB) was associated with inhibition of serum-induced DNA synthesis similar to that in untreated 3A-KO VSMCs. Transfection of 3A-KO VSMCs with p53 siRNA reduced p21 and MKP-1 levels and completely restored growth without affecting amounts of Cyclin-D1 and Rb phosphorylation. We conclude that PDE3A regulates VSMC growth via two complementary pathways, i.e. PKA-catalyzed inhibitory phosphorylation of Raf-1 with resulting inhibition of MAPK signaling and PKA/CREB-mediated induction of p21, leading to G0/G1 cell cycle arrest, as well as by increased accumulation of p53, which induces MKP-1, p21, and WIP1, leading to inhibition of G1 to S cell cycle progression.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/deficiência , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/genética , Deleção de Genes , Sistema de Sinalização das MAP Quinases/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Músculo Liso Vascular/citologia , Animais , Biocatálise/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Proteínas de Ciclo Celular/genética , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , DNA/biossíntese , Fosfatase 1 de Especificidade Dupla/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/genética , Técnicas de Inativação de Genes , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/enzimologia , Músculo Liso Vascular/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , RNA Interferente Pequeno/genética
4.
Am J Physiol Cell Physiol ; 287(4): C1077-86, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15355857

RESUMO

Diabetes mellitus is a major risk factor in the development of atherosclerosis and cardiovascular disease conditions, involving intimal injury and enhanced vascular smooth muscle cell (VSMC) migration. We report a mechanistic basis for divergences between insulin's inhibitory effects on migration of aortic VSMC from control Wistar Kyoto (WKY) rats versus Goto-Kakizaki (GK) diabetic rats. In normal WKY VSMC, insulin increased MAPK phosphatase-1 (MKP-1) expression as well as MKP-1 phosphorylation, which stabilizes it, and inhibited PDGF-mediated MAPK phosphorylation and cell migration. In contrast, basal migration was elevated in GK diabetic VSMCs, and all of insulin's effects on MKP-1 expression and phosphorylation, MAPK phosphorylation, and PDGF-stimulated migration were markedly inhibited. The critical importance of MKP-1 in insulin inhibition of VSMC migration was evident from several observations. MKP-1 small interfering RNA inhibited MKP-1 expression and abolished insulin inhibition of PDGF-induced VSMC migration. Conversely, adenoviral expression of MKP-1 decreased MAPK phosphorylation and basal migration rate and restored insulin's ability to inhibit PDGF-directed migration in GK diabetic VSMCs. Also, the proteasomal inhibitors lactacystin and MG132 partially restored MKP-1 protein levels in GK diabetic VSMCs and inhibited their migration. Furthermore, GK diabetic aortic VSMCs had reduced cGMP-dependent protein kinase Ialpha (cGK Ialpha) levels as well as insulin-dependent, but not sodium nitroprusside-dependent, stimulation of cGMP. Adenoviral expression of cGK Ialpha enhanced MKP-1 inhibition of MAPK phosphorylation and VSMC migration. We conclude that enhanced VSMC migration in GK diabetic rats is due at least in part to a failure of insulin-stimulated cGMP/cGK Ialpha signaling, MKP-1 expression, and stabilization and thus MAPK inactivation.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/metabolismo , Movimento Celular/fisiologia , Diabetes Mellitus Tipo 2/fisiopatologia , Proteínas Imediatamente Precoces/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Músculo Liso Vascular/fisiologia , Miócitos de Músculo Liso/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Animais , Western Blotting , Proteínas de Transporte/efeitos dos fármacos , Proteínas de Ciclo Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Modelos Animais de Doenças , Fosfatase 1 de Especificidade Dupla , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Proteínas Imediatamente Precoces/efeitos dos fármacos , Insulina/farmacologia , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Fosfoproteínas Fosfatases/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteína Fosfatase 1 , Proteínas Tirosina Fosfatases/efeitos dos fármacos , Ratos , Transdução de Sinais
5.
Hepatology ; 38(6): 1384-92, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14647049

RESUMO

Patients with hepatitis C virus (HCV) infection have a greater risk of developing type 2 diabetes mellitus. However, the mechanism of this association is unclear. In this study, we examined the potential defects in upstream insulin signaling pathways in liver specimens obtained from nonobese/nondiabetic subjects with HCV infection. Fasting liver biopsy specimens were obtained from 42 HCV-infected subjects and 10 non-HCV-infected subjects matched for age and body mass index. Liver tissues were exposed to insulin and examined for the contents and phosphorylation/activation status of the upstream insulin signaling molecules by immunoprecipitation and Western blot analysis. HCV infection resulted in a trend toward a 2-fold to 3-fold increase in insulin receptor (IR) and insulin receptor substrate (IRS)-1 contents when compared with non-HCV. In contrast, insulin-stimulated IRS-1 tyrosine phosphorylation was decreased by 2-fold in HCV-infected subjects compared with non-HCV-infected subjects (P <.05). The observed reductions in IRS-1 tyrosine phosphorylation were accompanied by a 3.4-fold decrease in IRS-1/p85 phosphatidylinositol 3-kinase (PI3-kinase) association and a 2.5-fold decrease in IRS-1-associated PI3-kinase enzymatic activity (P <.05 vs. non-HCV). This was accompanied by a marked reduction in insulin-stimulated Akt phosphorylation without any alterations in mitogen-activated protein kinase (MAPK) phosphorylation. Cellular contents of the hepatic p85 subunit of PI3-kinase were comparable between HCV-infected and non-HCV-infected subjects. In conclusion, we found that (1). HCV infection leads to a postreceptor defect in IRS-1 association with the IR and (2). insulin signaling defects in hepatic IRS-1 tyrosine phosphorylation and PI3-kinase association/activation may contribute to insulin resistance, which leads to the development of type 2 diabetes mellitus in patients with HCV infection.


Assuntos
Diabetes Mellitus Tipo 2/epidemiologia , Hepatite C/complicações , Fosfatidilinositol 3-Quinases/fisiologia , Fosfoproteínas/fisiologia , Proteínas Serina-Treonina Quinases , Transdução de Sinais/fisiologia , Adulto , Feminino , Hepatite C/metabolismo , Humanos , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina , Masculino , Pessoa de Meia-Idade , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Prevalência , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Tirosina/metabolismo
6.
Front Biosci ; 8: s796-804, 2003 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-12957877

RESUMO

An abnormal vasodilation is a major defect observed in the arteries of diabetic and hypertensive individuals. Myosin bound phosphatase (MBP) dephosphorylates myosin light chains which play a dominant role in vascular smooth muscle (VSM) contraction. Using two distinct approaches, we have demonstrated that insulin rapidly stimulates MBP and simultaneously inhibits RhoA/Rho kinase signaling via the nitric oxide (NO)/cGMP signaling pathway. Insulin activates MBP by decreasing Thr695 phosphorylation of myosin-bound subunit (MBS) via two different but cross-talking signaling pathways. Firstly, insulin inactivates Rho kinase by blocking RhoA activation and translocation to the membrane fraction via increased cGMP/cGK-1( mediated RhoA phosphorylation and decreased geranylgeranylation. Secondly, insulin induces iNOS expression via PI3-kinase signaling leading to generation of NO/cGMP which activates MBP via cGK-1( mediated inhibition of MBSThr695 phosphorylation via Rho kinase inactivation. MBP activation prevents agonist induced MLC20 phosphorylation as well as VSMC contraction. VSMCs isolated from SHR and diabetic rats exhibit elevations in Rho kinase, which increases MBS Thr695 phosphorylation and inhibits MBP. The defects appear to be at the level of PI3-kinase activation due to impaired insulin-induced IRS-1 tyrosine phosphorylation because of increased association of active Rho kinase with the IRS-1 leading to increased IRS-1 serine phosphorylation, which interrupts with downstream insulin signaling.


Assuntos
Insulina/fisiologia , Músculo Liso Vascular/química , Transdução de Sinais/fisiologia , Animais , Músculo Liso Vascular/citologia , Músculo Liso Vascular/fisiologia
7.
Am J Physiol Endocrinol Metab ; 285(1): E106-15, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12618360

RESUMO

Elevated levels of resistin have been proposed to cause insulin resistance and therefore may serve as a link between obesity and type 2 diabetes. However, its role in skeletal muscle metabolism is unknown. In this study, we examined the effect of resistin on insulin-stimulated glucose uptake and the upstream insulin-signaling components in L6 rat skeletal muscle cells that were either incubated with recombinant resistin or stably transfected with a vector containing the myc-tagged mouse resistin gene. Transfected clones expressed intracellular resistin, which was released in the medium. Incubation with recombinant resistin resulted in a dose-dependent inhibition of insulin-stimulated 2-deoxyglucose (2-DG) uptake. The inhibitory effect of resistin on insulin-stimulated 2-DG uptake was not the result of impaired GLUT4 translocation to the plasma membrane. Furthermore, resistin did not alter the insulin receptor (IR) content and its phosphorylation, nor did it affect insulin-stimulated insulin receptor substrate (IRS)-1 tyrosine phosphorylation, its association with the p85 subunit of phosphatidylinositol (PI) 3-kinase, or IRS-1-associated PI 3-kinase enzymatic activity. Insulin-stimulated phosphorylation of Akt/protein kinase B-alpha, one of the downstream targets of PI 3-kinase and p38 MAPK phosphorylation, was also not affected by resistin. Expression of resistin also inhibited insulin-stimulated 2-DG uptake when compared with cells expressing the empty vector (L6Neo) without affecting GLUT4 translocation, GLUT1 content, and IRS-1/PI 3-kinase signaling. We conclude that resistin does not alter IR signaling but does affect insulin-stimulated glucose uptake, presumably by decreasing the intrinsic activity of cell surface glucose transporters.


Assuntos
Glucose/metabolismo , Hormônios Ectópicos/farmacologia , Insulina/fisiologia , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas Musculares , Músculo Esquelético/metabolismo , Proteínas , Transdução de Sinais/efeitos dos fármacos , Animais , Antimetabólitos/farmacologia , Northern Blotting , Western Blotting , Linhagem Celular , DNA Complementar/biossíntese , DNA Complementar/genética , Desoxiglucose/farmacologia , Escherichia coli/metabolismo , Genes myc/genética , Transportador de Glucose Tipo 4 , Hormônios Ectópicos/biossíntese , Hormônios Ectópicos/genética , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos , Microscopia Confocal , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos , Fator de Crescimento Neural , Fosforilação , RNA Mensageiro/biossíntese , Ratos , Receptor de Insulina/efeitos dos fármacos , Receptor de Insulina/fisiologia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/farmacologia , Resistina , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo
8.
Biochem J ; 371(Pt 3): 857-66, 2003 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-12540292

RESUMO

Recent evidence suggests that glycogen-associated protein phosphatase 1 (PP-1(G)) is essential for basal and exercise-induced glycogen synthesis, which is mediated in part by dephosphorylation and activation of glycogen synthase (GS). In the present study, we examined the potential role of site-specific phosphorylation of PP-1(G) in heat-shock-induced glycogen synthesis. L6 rat skeletal-muscle cells were stably transfected with wild-type PP-1(G) or with PP-1(G) mutants in which site-1 (S1) Ser(48) and site-2 (S2) Ser(67) residues were substituted with Ala. Cells expressing wild-type and PP-1(G) mutants, S1, S2 and S1/S2, were examined for potential alterations in glycogen synthesis after a 60 min heat shock at 45 degrees C, followed by analysis of [(14)C]glucose incorporation into glycogen at 37 degrees C. PP-1(G) S1 mutation caused a 90% increase in glycogen synthesis on heat-shock treatment, whereas the PP-1(G) S2 mutant was not sensitive to heat stress. The S1/S2 double mutant was comparable with wild-type, which showed a 30% increase over basal. Heat-shock-induced glycogen synthesis was accompanied by increased PP-1 and GS activities. The highest activation was observed in S1 mutant. Heat shock also resulted in a rapid and sustained Akt/ glycogen synthase kinase 3 beta (GSK-3 beta) phosphorylation. Wortmannin blocked heat-shock-induced Akt/GSK-3 beta phosphorylation, prevented 2-deoxyglucose uptake and abolished the heat-shock-induced glycogen synthesis. Muscle glycogen levels regulate GS activity and glycogen synthesis and were found to be markedly depleted in S1 mutant on heat-shock treatment, suggesting that PP-1(G) S1 Ser phosphorylation may inhibit glycogen degradation during thermal stimulation, as S1 mutation resulted in excessive glycogen synthesis on heat-shock treatment. In contrast, PP-1(G) S2 Ser phosphorylation may promote glycogen breakdown under stressful conditions. Heat-shock-induced glycogenesis appears to be mediated via phosphoinositide 3-kinase/Akt-dependent GSK-3 beta inactivation as well as phosphoinositide 3-kinase-independent PP-1 activation.


Assuntos
Glicogênio/biossíntese , Resposta ao Choque Térmico , Músculo Esquelético/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Proteínas Serina-Treonina Quinases , Androstadienos/farmacologia , Animais , Linhagem Celular , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Inibidores Enzimáticos/farmacologia , Glicogênio/metabolismo , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Fatores de Transcrição de Choque Térmico , Músculo Esquelético/citologia , Músculo Esquelético/enzimologia , Fosfoproteínas Fosfatases/antagonistas & inibidores , Fosforilação , Proteína Fosfatase 1 , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Ratos , Fatores de Transcrição , Wortmanina
9.
Am J Physiol Cell Physiol ; 283(3): C704-13, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12176727

RESUMO

In this study, we examined the role of insulin in the control of vascular smooth muscle cell (VSMC) migration in the normal vasculature. Platelet-derived growth factor (PDGF) increased VSMC migration, which was inhibited by pretreatment with insulin in a dose-dependent manner. Insulin also caused a 60% decrease in PDGF-stimulated mitogen-activated protein kinase (MAPK) phosphorylation and activation. Insulin inhibition of MAPK was accompanied by a rapid induction of MAPK phosphatase (MKP-1), which inactivates MAPKs by dephosphorylation. Pretreatment with inhibitors of the nitric oxide (NO)/cGMP pathway, blocked insulin-induced MKP-1 expression and restored PDGF-stimulated MAPK activation and migration. In contrast, adenoviral infection of VSMCs with MKP-1 or cGMP-dependent protein kinase Ialpha (cGK Ialpha), the downstream effector of cGMP signaling, blocked the activation of MAPK and prevented PDGF-directed VSMC migration. Expression of antisense MKP-1 RNA prevented insulin's inhibitory effect and restored PDGF-directed VSMC migration and MAPK phosphorylation. We conclude that insulin inhibition of VSMC migration may be mediated in part by NO/cGMP/cGK Ialpha induction of MKP-1 and consequent inactivation of MAPKs.


Assuntos
Proteínas de Ciclo Celular , GMP Cíclico/análogos & derivados , Proteínas Imediatamente Precoces/metabolismo , Insulina/farmacologia , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Músculo Liso Vascular/efeitos dos fármacos , Fosfoproteínas Fosfatases , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteínas Tirosina Fosfatases/metabolismo , Animais , Becaplermina , Movimento Celular/efeitos dos fármacos , Células Cultivadas , GMP Cíclico/metabolismo , GMP Cíclico/farmacologia , Proteína Quinase Dependente de GMP Cíclico Tipo I , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Fosfatase 1 de Especificidade Dupla , Inibidores Enzimáticos/farmacologia , Humanos , Proteínas Imediatamente Precoces/antagonistas & inibidores , Proteínas Imediatamente Precoces/genética , Masculino , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II , Fosforilação/efeitos dos fármacos , Proteína Fosfatase 1 , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Proteínas Tirosina Fosfatases/genética , Proteínas Proto-Oncogênicas c-sis , RNA Antissenso/biossíntese , RNA Antissenso/farmacologia , Ratos , Ratos Endogâmicos WKY , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
10.
Diabetes ; 51(7): 2256-63, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12086958

RESUMO

Recent studies from our laboratory have shown that insulin induces relaxation of vascular smooth muscle cells (VSMCs) via stimulation of myosin phosphatase and inhibition of Rho kinase activity. In this study, we examined the mechanism whereby insulin inhibits Rho signaling and its impact on actin cytoskeleton organization. Incubation of confluent serum-starved VSMCs with thrombin or phenylephrine (PE) caused a rapid increase in glutathione S-transferase-Rhotekin-Rho binding domain-associated RhoA, Rho kinase activation, and actin cytoskeleton organization, which was blocked by preincubation with insulin. Preexposure to N(G)-monomethyl L-arginine acetate (L-NMMA), a nitric oxide synthase inhibitor, and Rp-8 CPT-cyclic guanosine monophosphate (RpcGMP), a cyclic guanosine monophosphate (cGMP) antagonist, attenuated the inhibitory effect of insulin on RhoA activation and restored thrombin-induced Rho kinase activation, and site-specific phosphorylation of the myosin-bound regulatory subunit (MBS(Thr695)) of myosin-bound phosphatase (MBP), and caused actin fiber reorganization. In contrast, 8-bromo-cGMP, a cGMP agonist, mimicked the inhibitory effects of insulin and abolished thrombin-mediated Rho activation. Insulin inactivation of RhoA was accompanied by inhibition of isoprenylation via reductions in geranylgeranyl transferase-1 activity as well as increased RhoA phosphorylation, which was reversed by pretreatment with RpcGMP and L-NMMA. We conclude that insulin may inhibit Rho signaling by affecting posttranslational modification of RhoA via nitric oxide/cGMP signaling pathway to cause MBP activation, actin cytoskeletal disorganization, and vasodilation.


Assuntos
Actinas/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/fisiologia , Citoesqueleto/fisiologia , Insulina/farmacologia , Músculo Liso Vascular/fisiologia , Óxido Nítrico/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/fisiologia , Proteína rhoA de Ligação ao GTP/fisiologia , 8-Bromo Monofosfato de Adenosina Cíclica/farmacologia , Alquil e Aril Transferases/metabolismo , Animais , Aorta Torácica , Células Cultivadas , GMP Cíclico/farmacologia , Citoesqueleto/efeitos dos fármacos , Ativação Enzimática , Glutationa Transferase/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Cinética , Músculo Liso Vascular/efeitos dos fármacos , Fenilefrina/farmacologia , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Transporte Proteico/efeitos dos fármacos , Ratos , Proteínas Recombinantes de Fusão/metabolismo , Trombina/farmacologia , ômega-N-Metilarginina/farmacologia , Quinases Associadas a rho
11.
Am J Physiol Endocrinol Metab ; 282(6): E1267-75, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12006356

RESUMO

Insulin action is decreased by high muscle glycogen concentrations in skeletal muscle. Patients with McArdle's disease have chronic high muscle glycogen levels and might therefore be at risk of developing insulin resistance. In this study, six patients with McArdle's disease and six matched control subjects were subjected to an oral glucose tolerance test and a euglycemic-hyperinsulinemic clamp. The muscle glycogen concentration was 103 +/- 45% higher in McArdle patients than in controls. Four of six McArdle patients, but none of the controls, had impaired glucose tolerance. The insulin-stimulated glucose utilization and the insulin-stimulated increase in glycogen synthase activity during the clamp were significantly lower in the patients than in controls (51.3 +/- 6.0 vs. 72.6 +/- 13.1 micromol x min(-1) x kg lean body mass(-1), P < 0.05, and 53 +/- 15 vs. 79 +/- 9%, P < 0.05, n = 6, respectively). The difference in insulin-stimulated glycogen synthase activity between the pairs was significantly correlated (r = 0.96, P < 0.002) with the difference in muscle glycogen level. The insulin-stimulated increase in Akt phosphorylation was smaller in the McArdle patients than in controls (45 +/- 13 vs. 76 +/- 13%, P < 0.05, respectively), whereas basal and insulin-stimulated glycogen synthase kinase 3alpha and protein phosphatase-1 activities were similar in the two groups. Furthermore, the ability of insulin to decrease and increase fat and carbohydrate oxidation, respectively, was blunted in the patients. In conclusion, these data show that patients with McArdle's glycogen storage disease are insulin resistant in terms of glucose uptake, glycogen synthase activation, and alterations in fuel oxidation. The data further suggest that skeletal muscle glycogen levels play an important role in the regulation of insulin-stimulated glycogen synthase activity.


Assuntos
Doença de Depósito de Glicogênio Tipo V/fisiopatologia , Insulina/farmacologia , Músculo Esquelético/efeitos dos fármacos , Proteínas Serina-Treonina Quinases , Adulto , Glicemia/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Ácidos Graxos não Esterificados/sangue , Feminino , Glucose/metabolismo , Técnica Clamp de Glucose , Teste de Tolerância a Glucose , Glicogênio/metabolismo , Glicogênio Fosforilase/metabolismo , Glicogênio Sintase/metabolismo , Quinase 3 da Glicogênio Sintase , Quinases da Glicogênio Sintase , Humanos , Resistência à Insulina , Masculino , Músculo Esquelético/metabolismo , Oxirredução , Fosfoproteínas Fosfatases/metabolismo , Fosforilação , Proteína Fosfatase 1 , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt
12.
J Biol Chem ; 277(8): 6214-22, 2002 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-11739394

RESUMO

Recent studies from our laboratory have shown that insulin stimulates myosin-bound phosphatase (MBP) in vascular smooth muscle cells (VSMCs) by decreasing site-specific phosphorylation of the myosin-bound subunit (MBS) of MBP via nitric oxide/cGMP-mediated Rho/Rho kinase inactivation. Here we tested potential interactions between Rho kinase and insulin signaling pathways. In control VSMCs, insulin inactivates ROK-alpha, the major Rho kinase isoform in VSMCs, and inhibits thrombin-induced increase in ROK-alpha association with the insulin receptor substrate-1 (IRS-1). Hypertension (in spontaneous hypertensive rats) or expression of an active RhoA(V14) up-regulates Rho kinase activity and increases ROK-alpha/IRS-1 association resulting in IRS-1 serine phosphorylation that leads to inhibition of both insulin-induced IRS-1 tyrosine phosphorylation and phosphatidylinositol 3-kinase (PI3-kinase) activation. In contrast, expression of dominant negative RhoA or cGMP-dependent protein kinase type I alpha inactivates Rho kinase, abolishes ROK-alpha/IRS-1 association, and potentiates insulin-induced tyrosine phosphorylation and PI3-kinase activation leading to decreased MBS(T695) phosphorylation and decreased MBP inhibition. Collectively, these results suggest a novel function for ROK-alpha in insulin signal transduction at the level of IRS-1 and potential cross-talk between cGMP-dependent protein kinase type I alpha, Rho/Rho kinase signaling, and insulin signaling at the level of IRS-1/PI3-kinase.


Assuntos
Insulina/fisiologia , Músculo Liso Vascular/fisiologia , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/fisiologia , Animais , Aorta , Células Cultivadas , Ativação Enzimática , Hipertensão/fisiopatologia , Insulina/farmacologia , Proteínas Substratos do Receptor de Insulina , Peptídeos e Proteínas de Sinalização Intracelular , Isoenzimas/metabolismo , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Fosfosserina/metabolismo , Proteínas Serina-Treonina Quinases/genética , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Quinases Associadas a rho
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