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1.
PLoS One ; 14(9): e0221567, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31550267

RESUMO

BACKGROUND AND AIMS: Limited data are available on the effectiveness and tolerability of direct-acting antivirals (DAAs) therapies in the real world for HCV-infected patients with comorbidities. This study aimed to describe the effectiveness of OBV/PTV/r ± DSV (3D/2D regimen) with or without ribavirin (RBV) in HCV or HCV/HIV co-infected patients with GT1/GT4 and CKD (IIIb-V stages), including those under hemodialysis and peritoneal dialysis in routine clinical practice in Spain in 2015. MATERIAL AND METHODS: Non-interventional, retrospective, multicenter data collection study in 31 Spanish sites. Socio-demographic, clinical variables, study treatment characteristics, effectiveness and tolerability data were collected from medical records. RESULTS: Data from 135 patients with a mean age (SD) of 58.3 (11.4) years were analyzed: 92.6% GT1 (81.6% GT1b and 17.6% GT1a) and 7.4% GT4, 14 (10.4%) HIV/HCV co-infected, 19.0% with fibrosis F3 and 28.1% F4 by FibroScan®, 52.6% were previously treated with pegIFN and RBV. 11.1%, 14.8% and 74.1% of patients had CKD stage IIIb, IV and V respectively. 68.9% of patients were on hemodialysis; 8.9% on peritoneal dialysis and 38.5% had history of renal transplant. A total of 125 (96.2%) of 135 patients were treated with 3D, 10 (7.4%) with 2D and 30.4% received RBV. The overall intention-to-treat (ITT) sustained virologic response at week 12 (SVR12) was 92.6% (125/135) and the overall modified-ITT (mITT) SVR12 was 99.2% (125/126). The SVR12 rates (ITT) per sub-groups were: HCV mono-infected (91.7%), HCV/HIV co-infected (100%), GT1 (92.0%), GT4 (100%), CKD stage IIIb (86.7%), stage IV (95%) and stage V (93%). Among the 10 non-SVR there was only 1 virologic failure (0.7%); 4 patients had missing data due lost to follow up (3.0%) and 5 patients discontinued 3D/2D regimen (3.7%): 4 due to severe adverse events (including 3 deaths) and 1 patient´s decision. CONCLUSIONS: These results have shown that 3D/2D regimens are effective and tolerable in patients with advanced CKD including those in dialysis with GT 1 or 4 chronic HCV mono-infection and HIV/HCV coinfection in a real-life cohort. The overall SVR12 rates were 92.6% (ITT) and 99.2% (mITT) without clinically relevant changes in eGFR until 12 weeks post-treatment. These results are consistent with those reported in clinical trials.


Assuntos
Antivirais/uso terapêutico , Coinfecção/tratamento farmacológico , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , HIV-1 , Hepatite C Crônica/complicações , Hepatite C Crônica/tratamento farmacológico , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/terapia , 2-Naftilamina , Idoso , Anilidas/uso terapêutico , Antivirais/administração & dosagem , Antivirais/efeitos adversos , Carbamatos/uso terapêutico , Ciclopropanos , Quimioterapia Combinada , Feminino , Genótipo , Hepacivirus/classificação , Hepacivirus/genética , Hepatite C Crônica/virologia , Humanos , Lactamas Macrocíclicas , Compostos Macrocíclicos/uso terapêutico , Masculino , Pessoa de Meia-Idade , Prolina/análogos & derivados , Diálise Renal , Estudos Retrospectivos , Ribavirina/uso terapêutico , Ritonavir/uso terapêutico , Espanha , Sulfonamidas/uso terapêutico , Resposta Viral Sustentada , Resultado do Tratamento , Uracila/análogos & derivados , Uracila/uso terapêutico , Valina
2.
AIDS Care ; 26(12): 1555-61, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25029599

RESUMO

CRANIum, a cross-sectional epidemiology study in Western Europe and Canada, was conducted to describe and compare the prevalence of a positive screen for neurocognitive impairment (NCI), depressive symptoms, and anxiety in an HIV-positive population either receiving combination antiretroviral therapy (cART) or who were naive to antiretroviral therapy (ART). HIV-positive patients ≥18 years of age attending a routine medical follow-up visit and able to complete the designated screening tools were eligible for study inclusion. The Brief Neurocognitive Screen was used to assess NCI; depressive and anxiety symptoms were assessed using the Hospital Anxiety and Depression Scale. The evaluable patient population (N = 2863) included 1766 men (61.7%) and 1096 (38.3%) women. A total of 1969 patients were cART-experienced (68.8%), and 894 were ART-naive (31.2%). A positive screen for NCI was found in 41.5% of patients (cART-experienced, 42.5%; ART-naive, 39.4%; p = 0.12). A positive screen for depressive symptoms was found in 15.7% of patients (cART-experienced, 16.8%; ART-naive, 13.3%; p = 0.01), whereas 33.3% of patients screened positive for anxiety (cART-experienced, 33.5%; ART-naive, 32.8%; p = 0.71). A greater percentage of women compared with men screened positive for NCI (51.78% vs. 35.1%; p < 0.0001) and depressive symptoms (17.9% vs. 14.3%; p = 0.01). These data suggest that neurocognitive and mood disorders remain highly prevalent in HIV-infected patients. Regular mental health screening in this population is warranted.


Assuntos
Ansiedade/psicologia , Depressão/psicologia , Infecções por HIV/psicologia , Complexo AIDS Demência/psicologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Antirretroviral de Alta Atividade/métodos , Ansiedade/epidemiologia , Canadá , Transtornos Cognitivos/psicologia , Estudos Transversais , Depressão/epidemiologia , Europa (Continente) , Feminino , Seguimentos , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Testes Neuropsicológicos , Prevalência , Inquéritos e Questionários
3.
Eur J Prev Cardiol ; 20(1): 21-8, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21947492

RESUMO

BACKGROUND: Cardiovascular (CV) disease mortality is increased in diabetes mellitus (DM) and metabolic syndrome (MS), conditions which share CV risk factors. AIM: The purpose of this study was to assess understanding of CV risk by patients with DM and/or MS diagnosed less than 1 year before and seen in primary care. Perception by these patients of their health state is also analysed. DESIGN: A multicentre, observational study in subjects diagnosed with DM diagnosed less than 1 year before and/or with MS, in whom agreement between CV risk perceived by patients and assessed by physicians was analysed. METHODS: Medical registry data and a survey of health status and perceived risk by patients and physicians. Agreement of patient perception of CV risk with perception of the physician in charge and with the CV risk established with clinical registry data was assessed. Self-perceived health status was also studied. RESULTS: A total of 150 physicians recruited 681 patients (71.5% with DM and 28.5% with MS) aged 60.8 ± 10.8 years (55.8% males). Good or excellent health were reported by 41.3% and 0.9%, respectively. Inability to give an estimate of CV risk was found in 39.8%. Agreement between the CV risks perceived by patients and evaluated by chart was poor: kappa index 0.145 (95% CI 0.101-0.189), p < 0.001. Agreement between CV risk perceived by patients and clinical data in the medical registry was weak: kappa index 0.165 (95% CI 0.117-0.213), p < 0.001. CONCLUSIONS: Patients with recently diagnosed DM and/or with MS have a poor awareness of their CV risk and 42.2% of them think that they have good or excellent health.


Assuntos
Doenças Cardiovasculares/psicologia , Diabetes Mellitus Tipo 2/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Síndrome Metabólica/psicologia , Idoso , Pressão Sanguínea/fisiologia , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/diagnóstico , Dislipidemias/psicologia , Feminino , Nível de Saúde , Inquéritos Epidemiológicos , Humanos , Masculino , Síndrome Metabólica/diagnóstico , Pessoa de Meia-Idade , Prevalência , Atenção Primária à Saúde , Sistema de Registros , Fatores de Risco
4.
Free Radic Biol Med ; 52(6): 1093-100, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22281399

RESUMO

Laminar shear stress (LSS) is a protective hemodynamic regulator of endothelial function and limits the development of atherosclerosis and other vascular wall diseases related to pathophysiological generation of reactive oxygen species. LSS activates several endothelial signaling responses, including the activation of MAPKs and eNOS. Here, we explored the mechanisms of activation of these key endothelial signaling pathways. Using the cone/plate model we found that LSS (12 dyn/cm(2)) rapidly promotes endothelial intracellular generation of superoxide and hydrogen peroxide (H(2)O(2)). Physiological concentrations of H(2)O(2) (flux of 0.1 nM/min and 15 µM added extracellularly) significantly activated both eNOS and p38 MAPK. Pharmacological inhibition of NADPH oxidases (NOXs) and specific knockdown of NOX4 decreased LSS-induced p38 MAPK activation. Whereas the absence of eNOS did not alter LSS-induced p38 MAPK activation, pharmacological inhibition and knockdown of p38α MAPK blocked H(2)O(2)- and LSS-induced eNOS phosphorylation and reduced (•)NO levels. We propose a model in which LSS promotes the formation of signaling levels of H(2)O(2), which in turn activate p38α MAPK and then stimulate eNOS, leading to increased (•)NO generation and protection of endothelial function.


Assuntos
Hemodinâmica , Peróxido de Hidrogênio/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Resistência ao Cisalhamento , Estresse Mecânico , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Aterosclerose/metabolismo , Aterosclerose/patologia , Bovinos , Linhagem Celular , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/genética , Inibidores Enzimáticos/farmacologia , Camundongos , Camundongos Knockout , NADPH Oxidase 4 , NADPH Oxidases/genética , NADPH Oxidases/metabolismo , Óxido Nítrico Sintase Tipo III/genética , RNA Interferente Pequeno/genética , Fluxo Sanguíneo Regional , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética
6.
Diabetes ; 57(12): 3211-21, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18796617

RESUMO

OBJECTIVE: Cytokines are elevated in various insulin-resistant states, including type 2 diabetes and obesity, although the contribution of interleukin-6 (IL-6) in the induction of these diseases is controversial. RESEARCH DESIGN AND METHODS: We analyzed the impact of IL-6 on insulin action in murine primary myocytes, skeletal muscle cell lines, and mice (wild type and protein-tyrosine phosphatase 1B [PTP1B] deficient). RESULTS: IL-6 per se increased glucose uptake by activating serine/threonine protein kinase 11 (LKB1)/AMP-activated protein kinase/protein kinase B substrate of 160 kDa (AS160) pathway. A dual effect on insulin action was observed when myotubes and mice were exposed to this cytokine: additive with short-term insulin (increased glucose uptake and systemic insulin sensitivity) but chronic exposure produced insulin resistance (impaired GLUT4 translocation to plasma membrane and defects in insulin signaling at the insulin receptor substrate 1 [IRS-1] level). Three mechanisms seem to operate in IL-6-induced insulin resistance: activation of c-Jun NH(2)-terminal kinase 1/2 (JNK1/2), accumulation of suppressor of cytokine signaling 3 (socs3) mRNA, and an increase in PTP1B activity. Accordingly, silencing JNK1/2 with either small interfering RNA or chemical inhibitors impaired phosphorylation of IRS-1 (Ser307), restored insulin signaling, and normalized insulin-induced glucose uptake in myotubes. When using a pharmacological approach, liver X receptor agonists overcome IL-6-induced insulin resistance by producing downregulation of socs3 and ptp1b gene expression. Finally, the lack of PTP1B confers protection against IL-6-induced insulin resistance in skeletal muscle in vitro and in vivo, in agreement with the protection against the IL-6 hyperglycemic effect observed on glucose and insulin tolerance tests in adult male mice. CONCLUSIONS: These findings indicate the important role of IL-6 in the pathogenesis of insulin resistance and further implicate PTP1B as a potential therapeutic target in the treatment of type 2 diabetes.


Assuntos
Insulina/farmacologia , Interleucina-6/fisiologia , Células Musculares/fisiologia , Músculo Esquelético/fisiologia , Adenilato Quinase/efeitos dos fármacos , Adenilato Quinase/metabolismo , Animais , Animais Recém-Nascidos , Transporte Biológico/efeitos dos fármacos , Extremidades , Glucose/metabolismo , Transportador de Glucose Tipo 4/efeitos dos fármacos , Transportador de Glucose Tipo 4/metabolismo , Camundongos , Células Musculares/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Mioblastos/fisiologia , Reação em Cadeia da Polimerase , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/fisiologia , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Interferente Pequeno/genética
7.
Endocrinology ; 149(2): 793-801, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17962350

RESUMO

Activating ras point mutations are frequently found in skeletal muscle tumors such as rhabdomyosarcomas. In this study we investigated the impact of two different H-ras mutants in skeletal muscle differentiation: RasV12, a constitutively active form, and RasV12C40, a mutant deficient in Raf1 activation. Stably transfected C2C12-RasV12 myoblasts actively proliferated as indicated by the sustained expression of proliferating cell nuclear antigen and retinoblastoma at the hyperphosphorylated state and failed to express differentiation markers. This differentiation-defective phenotype was a consequence of the chronic p44/p42MAPK phosphorylation and the inability of the cells to activate AKT. Moreover, we observed that p44/p42MAPK activation in C2C12-RasV12 myoblasts phosphorylated the ETS-like transcription factor (ELK) 1, which translocates to the nuclei and seemed to be involved in maintaining myoblast proliferation. C2C12-RasV12C40 myoblasts cultured in low serum repressed phosphorylation of p44/p42MAPK and ELK1, resulting in cell cycle arrest and myogenic differentiation. Under this condition, activation of AKT, p70S6K, and p38MAPK was produced, leading to formation of myotubes in 3 d, 1 d earlier than in control C2C12-AU5 cells. Moreover, the expression of muscle-specific proteins, mainly the terminal differentiation markers caveolin-3 and myosin heavy chain, also occurred 1 d earlier than in control cells. Furthermore, AKT activation produced phosphorylation of Forkhead box O that led to nuclear exclusion and inactivation, allowing myogenesis. In addition, we found an induction of nuclear factor-kappaB activity in the nucleus in C2C12-RasV12C40 myotubes attributed to p38MAPK activation. Accordingly, muscle differentiation is associated with a pattern of transcription factors that involves nuclear exclusion ELK1 and Forkhead box O and the increase in nuclear factor-kappaB DNA binding.


Assuntos
Fatores de Transcrição Forkhead/metabolismo , Mioblastos/citologia , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Elk-1 do Domínio ets/metabolismo , Animais , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Linhagem Celular , Núcleo Celular/metabolismo , Proteína Forkhead Box O1 , Sistema de Sinalização das MAP Quinases/fisiologia , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/citologia , Mutagênese , Mioblastos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
8.
Diabetes ; 56(2): 404-13, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17259385

RESUMO

Protein-tyrosine phosphatase (PTP)1B is a negative regulator of insulin signaling and a therapeutic target for type 2 diabetes. In this study, we have assessed the role of PTP1B in the insulin sensitivity of skeletal muscle under physiological and insulin-resistant conditions. Immortalized myocytes have been generated from PTP1B-deficient and wild-type neonatal mice. PTP1B(-/-) myocytes showed enhanced insulin-dependent activation of insulin receptor autophosphorylation and downstream signaling (tyrosine phosphorylation of insulin receptor substrate [IRS]-1 and IRS-2, activation of phosphatidylinositol 3-kinase, and serine phosphorylation of AKT), compared with wild-type cells. Accordingly, PTP1B(-/-) myocytes displayed higher insulin-dependent stimulation of glucose uptake and GLUT4 translocation to the plasma membrane than wild-type cells. Treatment with tumor necrosis factor-alpha (TNF-alpha) induced insulin resistance on glucose uptake, impaired insulin signaling, and increased PTP1B activity in wild-type cells. Conversely, the lack of PTP1B confers protection against insulin resistance by TNF-alpha in myocyte cell lines and in adult male mice. Wild-type mice treated with TNF-alpha developed a pronounced hyperglycemia along the glucose tolerance test, accompanied by an impaired insulin signaling and increased PTP1B activity in muscle. However, mice lacking PTP1B maintained a rapid clearance of glucose and insulin sensitivity and displayed normal muscle insulin signaling regardless the presence of TNF-alpha.


Assuntos
Transportador de Glucose Tipo 4/efeitos dos fármacos , Resistência à Insulina/fisiologia , Insulina/metabolismo , Células Musculares/metabolismo , Proteínas Tirosina Fosfatases/deficiência , Fator de Necrose Tumoral alfa/farmacologia , Animais , Animais Recém-Nascidos , Linhagem Celular , Modelos Animais de Doenças , Vetores Genéticos , Glucose/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Masculino , Camundongos , Camundongos Knockout , Músculo Esquelético/citologia , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 1 , Proteínas Tirosina Fosfatases/metabolismo , Receptor de Insulina/efeitos dos fármacos , Transdução de Sinais , Transfecção
9.
Mol Biol Cell ; 16(9): 4454-61, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16000370

RESUMO

Myoblast C2C12 cells cultured in the presence of FGF2 actively proliferate and showed a differentiation-defective phenotype compared with cells cultured in low serum or in the presence of insulin. These FGF2 effects are associated with sustained activation of p44/p42-MAPK and lack of activation of AKT. Here we demonstrate that Sprouty-2, a protein involved in the negative feedback of receptor tyrosine kinase signaling, when stably overexpressed in C2C12 cells and in the presence of FGF2 produces growth arrest (precluding the expression of PCNA and the phosphorylation of retinoblastoma and inducing the expression of p21(CIP)) and myogenesis (multinucleated myotubes formation, induction of creatine kinase and expression of myosin heavy chain protein). These events were accompanied by repression of p44/p42-MAPK and activation of AKT. When C2C12 cells were stably transfected with a Sprouty-2 (Y55F) mutant defective in inhibiting p44/p42-MAPK activation by FGF, myoblasts in the presence of FGF continue to grow and completely fail to form myotubes. This work is the first evidence of the contribution of sprouty genes to myogenic differentiation in the presence of FGF2.


Assuntos
Diferenciação Celular/fisiologia , Fator 2 de Crescimento de Fibroblastos/fisiologia , Mioblastos/metabolismo , Proteínas/genética , Proteínas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Substituição de Aminoácidos , Animais , Linhagem Celular , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas de Membrana , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Músculo Esquelético/fisiologia , Mutação , Mioblastos/citologia , Proteínas Serina-Treonina Quinases
10.
J Biol Chem ; 279(17): 17070-8, 2004 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-14764603

RESUMO

Insulin stimulation produced a reliable 3-fold increase in glucose uptake in primary neonatal rat myotubes, which was accompanied by a similar effect on GLUT4 translocation to plasma membrane. Tumor necrosis factor (TNF)-alpha caused insulin resistance on glucose uptake and GLUT4 translocation by impairing insulin stimulation of insulin receptor (IR) and IR substrate (IRS)-1 and IRS-2 tyrosine phosphorylation, IRS-associated phosphatidylinositol 3-kinase activation, and Akt phosphorylation. Because this cytokine produced sustained activation of stress and proinflammatory kinases, we have explored the hypothesis that insulin resistance by TNF-alpha could be mediated by these pathways. In this study we demonstrate that pretreatment with PD169316 or SB203580, inhibitors of p38 MAPK, restored insulin signaling and normalized insulin-induced glucose uptake in the presence of TNF-alpha. However, in the presence of PD98059 or SP600125, inhibitors of p42/p44 MAPK or JNK, respectively, insulin resistance by TNF-alpha was still produced. Moreover, TNF-alpha produced inhibitor kappaB kinase (IKK)-beta activation and inhibitor kappaB-beta and -alpha degradation in a p38 MAPK-dependent manner, and treatment with salicylate (an inhibitor of IKK) completely restored insulin signaling. Furthermore, TNF-alpha produced serine phosphorylation of IR and IRS-1 (total and on Ser(307) residue), and these effects were completely precluded by pretreatment with either PD169316 or salicylate. Consequently, TNF-alpha, through activation of p38 MAPK and IKK, produces serine phosphorylation of IR and IRS-1, impairing its tyrosine phosphorylation by insulin and the corresponding activation of phosphatidylinositol 3-kinase and Akt, leading to insulin resistance on glucose uptake and GLUT4 translocation.


Assuntos
Resistência à Insulina , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Músculo Esquelético/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Animais , Transporte Biológico , Western Blotting , Membrana Celular/metabolismo , Células Cultivadas , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Glucose/metabolismo , Glucose/farmacocinética , Quinase I-kappa B , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina , Peptídeos e Proteínas de Sinalização Intracelular , Fosfatidilinositol 3-Quinases/metabolismo , Fosfoproteínas/metabolismo , Fosforilação , Testes de Precipitina , Transporte Proteico , Ratos , Ácido Salicílico/farmacologia , Serina/metabolismo , Transdução de Sinais , Frações Subcelulares/metabolismo , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo , Tirosina/química , Tirosina/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno
11.
Oncogene ; 21(23): 3739-53, 2002 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-12032842

RESUMO

v-H-ras transformed C2C12 (C2Ras) myoblasts, overexpressing p21-Ras protein in the Ras-GTP active form, showed a differentiation-defective phenotype when cultured in low serum as compared with C2C12 myoblasts. Accordingly, the purpose of the present study was to delineate the signaling pathways that restore C2Ras myoblasts differentiation. Inhibition of p42/p44-MAPK with the chemical inhibitor PD98059, and activation of AKT/P70S6K and p38-MAPK with insulin, produced growth arrest (precluding the expression of PCNA, cyclin-D1 and retinoblastoma at the hyperphosphorylated state and inducing the expression of the cell cycle inhibitor p21(Cip)) and myogenesis (multinucleated myotubes formation and induction of creatine kinase, caveolin-3 and alpha-actin). Both events were accompanied by down-regulation of AP-1 and up-regulation of NF-kappaB transcriptional activities. Furthermore, inhibition of NF-kappaB transcriptional activity by the use of the proteasome inhibitor MG132 totally precluded differentiation by insulin+PD98059, demonstrating a direct role for NF-kappaB on C2Ras myogenesis. C2Ras myoblasts failed to restore differentiation when rapamycin or PD169316 were added in the presence of insulin+PD98059, indicating that the activation of both P70S6K and p38-MAPK was necessary to reach a fully differentiated phenotype. Finally, transient transfection of a constitutively active Myr-EGFP-AKT-HA construct (in the presence of PD98059) restored C2Ras myogenesis by its ability to activate P70S6K and p38-MAPK. A crosstalk between P70S6K and p38-MAPK was observed under rapamycin treatment in both insulin or active AKT induced myogenesis. Our results are delineating an AKT/P70S6K/p38-MAPK pathway involved in skeletal muscle differentiation.


Assuntos
Transformação Celular Neoplásica/patologia , Insulina/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo , Proteínas ras/fisiologia , Animais , Diferenciação Celular/efeitos dos fármacos , Transformação Celular Neoplásica/metabolismo , Meios de Cultura Livres de Soro/farmacologia , Camundongos , Proteína Quinase 14 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais/efeitos dos fármacos , Transfecção , Células Tumorais Cultivadas
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