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1.
NPJ Schizophr ; 5(1): 17, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591400

RESUMO

Although most patients who experience a first-episode of psychosis achieve remission of positive psychotic symptoms, relapse is common. Existing relapse evaluation strategies are limited by their reliance on direct and timely contact with professionals, and accurate reporting of symptoms. A method by which to objectively identify early relapse warning signs could facilitate swift intervention. We collected 52,815 Facebook posts across 51 participants with recent onset psychosis (mean age = 23.96 years; 70.58% male) and applied anomaly detection to explore linguistic and behavioral changes associated with psychotic relapse. We built a one-class classification model that makes patient-specific personalized predictions on risk to relapse. Significant differences were identified in the words posted to Facebook in the month preceding a relapse hospitalization compared to periods of relative health, including increased usage of words belonging to the swear (p < 0.0001, Wilcoxon signed rank test), anger (p < 0.001), and death (p < 0.0001) categories, decreased usage of words belonging to work (p = 0.00579), friends (p < 0.0001), and health (p < 0.0001) categories, as well as a significantly increased use of first (p < 0.0001) and second-person (p < 0.001) pronouns. We additionally observed a significant increase in co-tagging (p < 0.001) and friending (p < 0.0001) behaviors in the month before a relapse hospitalization. Our classifier achieved a specificity of 0.71 in predicting relapse. Results indicate that social media activity captures objective linguistic and behavioral markers of psychotic relapse in young individuals with recent onset psychosis. Machine-learning models were capable of making personalized predictions of imminent relapse hospitalizations at the patient-specific level.

2.
Oncogene ; 35(31): 4058-68, 2016 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-26686093

RESUMO

Arginylation is an emerging post-translational modification mediated by arginyltransferase (ATE1) that is essential for mammalian embryogenesis and regulation of the cytoskeleton. Here, we discovered that Ate1-knockout (KO) embryonic fibroblasts exhibit tumorigenic properties, including abnormally rapid contact-independent growth, reduced ability to form cell-cell contacts and chromosomal aberrations. Ate1-KO fibroblasts can form large colonies in Matrigel and exhibit invasive behavior, unlike wild-type fibroblasts. Furthermore, Ate1-KO cells form tumors in subcutaneous xenograft assays in immunocompromised mice. Abnormal growth in these cells can be partially rescued by reintroduction of stably expressed specific Ate1 isoforms, which also reduce the ability of these cells to form tumors. Tumor array studies and bioinformatics analysis show that Ate1 is downregulated in several types of human cancer samples at the protein level, and that its transcription level inversely correlates with metastatic progression and patient survival. We conclude that Ate1-KO results in carcinogenic transformation of cultured fibroblasts, suggesting that in addition to its previously known activities Ate1 gene is essential for tumor suppression and also likely participates in suppression of metastatic growth.


Assuntos
Aminoaciltransferases/fisiologia , Neoplasias/enzimologia , Proteínas Supressoras de Tumor/fisiologia , Aminoaciltransferases/análise , Animais , Células Cultivadas , Aberrações Cromossômicas , Humanos , Camundongos , Metástase Neoplásica
3.
Acta Physiol (Oxf) ; 200(1): 75-85, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20236253

RESUMO

AIM: The protein kinase B (PKB)/Akt is known to stimulate the cellular uptake of glucose and amino acids. The kinase is expressed in proximal renal tubules. The present study explored the influence of Akt/PKB on renal tubular phosphate transport. METHODS: The renal phosphate transporter NaPi-IIa was expressed in Xenopus oocytes with or without PKB/Akt and Na(+) phosphate cotransport determined using dual electrode voltage clamp. Renal phosphate excretion was determined in Akt2/PKBbeta knockout mice (akt2(-/-)) and corresponding wild-type mice (akt2(+/+)). Transporter protein abundance was determined using Western blotting and phosphate transport by (32)P uptake into brush border membrane vesicles. RESULTS: The phosphate-induced current in NaPi-IIa-expressing Xenopus oocytes was significantly increased by the coexpression of Akt/PKB. Phosphate excretion [micromol per 24 h per g BW] was higher by 91% in akt2(-/-) than in akt2(+/+) mice. The phosphaturia of akt2(-/-) mice occurred despite normal transport activity and expression of the renal phosphate transporters NaPi-IIa, NaPi-IIc and Pit2 in the brush border membrane, a significantly decreased plasma PTH concentration (by 46%) and a significantly enhanced plasma 1,25-dihydroxyvitamin D(3) concentration (by 46%). Moreover, fractional renal Ca(2+) excretion was significantly enhanced (by 53%) and bone density significantly reduced (by 11%) in akt2(-/-) mice. CONCLUSIONS: Akt2/PKBbeta plays a role in the acute regulation of renal phosphate transport and thus contributes to the maintenance of phosphate balance and adequate mineralization of bone.


Assuntos
Túbulos Renais/enzimologia , Fosfatos/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/metabolismo , Animais , Transporte Biológico , Biomarcadores/sangue , Biomarcadores/urina , Western Blotting , Calcificação Fisiológica , Calcitriol/sangue , Feminino , Homeostase , Hipofosfatemia Familiar/enzimologia , Hipofosfatemia Familiar/genética , Masculino , Potenciais da Membrana , Camundongos , Camundongos Knockout , Microvilosidades/enzimologia , Hormônio Paratireóideo/sangue , Técnicas de Patch-Clamp , Proteínas Proto-Oncogênicas c-akt/deficiência , Proteínas Proto-Oncogênicas c-akt/genética , Ratos , Sódio/metabolismo , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/genética , Xenopus
4.
Neuroscience ; 164(3): 908-17, 2009 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-19735699

RESUMO

We previously showed that when rats were trained to fear an auditory conditioned stimulus (CS) by pairing it with a mild unilateral shock to the eyelid (the unconditioned stimulus, or US), conditioned freezing depended upon the amygdala contralateral but not ipsilateral from the US. It was proposed that convergent activation of amygdala neurons by the CS and US occurred mainly in the amygdala contralateral from US delivery, causing memories of the CS-US association to be stored primarily by that hemisphere. In the present study, we further tested this interpretation by administering unilateral infusions of U0126 (in 50% dimethyl sulfoxide (DMSO) vehicle) to block phosphorylation of extracellular signal-responsive kinase (ERK) in the amygdala prior to CS-US pairings. Conditioned freezing was impaired 24 h after training when U0126 was infused contralaterally-but not ipsilaterally-from the US, suggesting that fear memories were consolidated mainly by the contralateral amygdala. However, immunostaining experiments revealed that ERK phosphorylation was elevated in both hemispheres of the amygdale's lateral (LA) and centrolateral (CeL) nuclei after paired (but not unpaired (UNP)) presentations of the CS and US. Thus, fear acquisition induced ERK phosphorylation bilaterally in the amygdala, even though the ipsilateral hemisphere did not appear to participate in conditioned freezing. These findings suggest that associative plasticity may occur in both amygdala hemispheres even when only one hemisphere is involved in freezing behavior. Conditioning-induced ERK phosphorylation was identical in both hemispheres of LA, but was slightly greater in the contralateral than ipsilateral hemisphere of CeL. Hence, asymmetric induction of plasticity in CeL might help to explain why conditioned freezing depends preferentially upon the amygdala contralateral from the US in our fear conditioning paradigm.


Assuntos
Tonsila do Cerebelo/enzimologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Medo/fisiologia , Lateralidade Funcional/fisiologia , Tonsila do Cerebelo/anatomia & histologia , Animais , Butadienos/farmacologia , Condicionamento Psicológico/efeitos dos fármacos , Condicionamento Psicológico/fisiologia , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Reação de Congelamento Cataléptica/efeitos dos fármacos , Reação de Congelamento Cataléptica/fisiologia , Lateralidade Funcional/efeitos dos fármacos , Imuno-Histoquímica , Masculino , Memória/fisiologia , Vias Neurais/anatomia & histologia , Vias Neurais/efeitos dos fármacos , Vias Neurais/enzimologia , Plasticidade Neuronal/efeitos dos fármacos , Plasticidade Neuronal/fisiologia , Nitrilas/farmacologia , Fosforilação/efeitos dos fármacos , Ratos , Ratos Long-Evans
5.
Oncogene ; 27(16): 2320-36, 2008 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-18391974

RESUMO

Forkhead proteins, and FoxO1 in particular, play a significant role in regulating whole body energy metabolism. Glucose homeostasis is achieved by adjusting endogenous glucose production as well as glucose uptake by peripheral tissues in response to insulin. In the fasted state, the liver is primarily responsible for maintaining glucose levels, with FoxO1 playing a key role in promoting the expression of gluconeogenic enzymes. Following feeding, pancreatic beta cells secrete insulin, which promotes the uptake of glucose by peripheral tissues including skeletal muscle and adipose tissue, and can in part suppress gluconeogenic enzyme expression in the liver. In addition to directly regulating metabolism, FoxO1 also plays a role in the formation of both adipose tissue and skeletal muscle, two major organs that are critical for maintaining energy homeostasis. The importance of FoxO1 in energy homeostasis is particularly striking under conditions of metabolic dysfunction or insulin resistance. In obese or diabetic states, FoxO1-dependent gene expression promotes some of the deleterious characteristics associated with these conditions, including hyperglycemia and glucose intolerance. In addition, the increase in pancreatic beta cell mass that normally occurs in response to a rise in insulin demand is blunted by nuclear FoxO1 expression. However, under these same pathophysiological conditions, FoxO1 expression may help drive the expression of genes involved in combating oxidative stress, thereby preserving cellular function. FoxO1 may also be involved in promoting the switch from carbohydrate to fatty acid as the major energy source during starvation.


Assuntos
Metabolismo Energético/fisiologia , Fatores de Transcrição Forkhead/fisiologia , Animais , Humanos
6.
Biochem Soc Trans ; 31(Pt 1): 216-9, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12546688

RESUMO

AMP-activated protein kinase (AMPK) is viewed as a fuel sensor for glucose and lipid metabolism. To understand better the physiological role of the catalytic AMPK subunit isoforms, we generated two knockout mouse models with the alpha1 (AMPK alpha 1(-/-)) and alpha 2 (AMPK alpha 2(-/-)) catalytic subunit genes deleted. No defect in glucose homoeostasis was observed in AMPK alpha 1(-/-) mice. On the other hand, AMPK alpha 2(-/-) mice presented high plasma glucose levels and low plasma insulin concentrations in the fed period and during the glucose tolerance test. Nevertheless, in isolated AMPK alpha 2(-/-) pancreatic islets, glucose-stimulated insulin secretion was not affected. Surprisingly, AMPK alpha 2(-/-) mice were insulin-resistant and had reduced muscle glycogen synthesis as assessed in vivo by the hyperinsulinaemic euglycaemic clamp procedure. Reduction of insulin sensitivity and glycogen synthesis were not dependent on the lack of AMPK in skeletal muscle, since mice expressing a dominant inhibitory mutant of AMPK in skeletal muscle were not affected and since insulin-stimulated glucose transport in incubated muscles in vitro was normal in AMPK alpha 2(-/-) muscles. Furthermore, AMPK alpha 2(-/-) mice have a higher sympathetic tone, as shown by increased catecholamine urinary excretion. Increased adrenergic tone could explain both decreased insulin secretion and insulin resistance observed in vivo in AMPK alpha 2(-/-) mice. We suggest that the alpha2 catalytic subunit of AMPK plays a major role as a fuel sensor by modulating the activity of the autonomous nervous system in vivo.


Assuntos
Complexos Multienzimáticos/genética , Complexos Multienzimáticos/fisiologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Quinases Ativadas por AMP , Animais , Domínio Catalítico , Teste de Tolerância a Glucose , Glicogênio/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Modelos Biológicos , Complexos Multienzimáticos/metabolismo , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Mutação , Proteínas Serina-Treonina Quinases/metabolismo
7.
Biochem Soc Trans ; 31(Pt 1): 236-41, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12546693

RESUMO

AMP-activated protein kinase (AMPK) is becoming recognized as a critical regulator of energy metabolism in cells. Using a mouse model in which we specifically blocked AMPK activity in muscles, we have demonstrated that activation of AMPK is necessary for the effects of 5-aminoimidazole-4-carboxamide riboside ('AICAR') and hypoxia, and is possibly required for a portion of exercise-induced glucose uptake. These same mice could not maintain sufficient glycogen in their skeletal muscle and it was rapidly depleted when the animals were subjected to mild exercise. Using isolated strips, we observed muscle hypertrophy and increased tiredness in the AMPK-deficient muscle. We also performed microarray analysis and showed dramatic changes of transcription profile in muscles of the lazy mice. These could have a significant impact on muscle function and may contribute to the observed phenotype.


Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Inibidores Enzimáticos , Complexos Multienzimáticos/antagonistas & inibidores , Complexos Multienzimáticos/fisiologia , Músculo Esquelético/enzimologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Quinases Ativadas por AMP , Aminoimidazol Carboxamida/farmacologia , Animais , Glicogênio/metabolismo , Glicogênio Sintase/metabolismo , Hipertrofia , Hipóxia , Camundongos , Complexos Multienzimáticos/genética , Mutação , Fenótipo , Condicionamento Físico Animal , Proteínas Serina-Treonina Quinases/genética , Ribonucleotídeos/farmacologia , Fatores de Tempo , Transcrição Gênica
8.
Am J Physiol Endocrinol Metab ; 281(6): E1249-54, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11701440

RESUMO

Insulin stimulates muscle and adipose tissue to absorb glucose through a signaling cascade that is incompletely understood. Insulin resistance, the inability of insulin to appropriately stimulate glucose uptake, is a hallmark of type 2 diabetes mellitus. The development of experimental systems that model human insulin resistance is important in elucidating the defects responsible for the development of type 2 diabetes. When two strains of mice, BTBR and C57BL/6J (B6), are crossed, the resultant male offspring (BtB6) demonstrate insulin resistance in muscle tissue. Here, we report an insulin resistance phenotype in adipose tissue from lean, nondiabetic BtB6 mice similar to that observed in human muscle. Adipocytes isolated from insulin-resistant male mice display 65% less insulin-stimulated glucose uptake compared with insulin-sensitive female mice. Similarly, adipocytes from insulin-resistant mice have diminished insulin-stimulated IRS-1 phosphorylation and phosphatidylinositol 3-kinase (PI3K) activation. However, normal activation of protein kinase B (Akt/PKB) by insulin is observed. Thus BtB6 mice demonstrate the dissociation of insulin-stimulated PI3K activity and Akt/PKB activation and represent a useful model to investigate the causes of insulin resistance in humans.


Assuntos
Resistência à Insulina/fisiologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas , Adipócitos/enzimologia , Animais , Western Blotting , Ativação Enzimática/fisiologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos , Fosforilação , Proteínas Proto-Oncogênicas c-akt , Receptor de Insulina/metabolismo
9.
Nat Med ; 7(10): 1133-7, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11590437

RESUMO

The physiological performance of an organ depends on an interplay between changes in cellular function and organ size, determined by cell growth, proliferation and death. Nowhere is this more evident than in the endocrine pancreas, where disturbances in function or mass result in severe disease. Recently, the insulin signal-transduction pathway has been implicated in both the regulation of hormone secretion from beta cells in mammals as well as the determination of cell and organ size in Drosophila melanogaster. A prominent mediator of the actions of insulin and insulin-like growth factor 1 (IGF-1) is the 3'-phosphoinositide-dependent protein kinase Akt, also known as protein kinase B (PKB). Here we report that overexpression of active Akt1 in the mouse beta cell substantially affects compartment size and function. There was a significant increase in both beta-cell size and total islet mass, accompanied by improved glucose tolerance and complete resistance to experimental diabetes.


Assuntos
Ilhotas Pancreáticas/citologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas , Animais , Divisão Celular , Tamanho Celular , Sobrevivência Celular , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/prevenção & controle , Ativação Enzimática , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-akt , Ratos
10.
Neurology ; 57(6): 1050-4, 2001 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-11571333

RESUMO

BACKGROUND: Unverricht-Lundborg disease (ULD) is the prototypical form of progressive myoclonus epilepsy, and subjects are usually very photosensitive. ULD is caused by mutations in the cystatin B (CSTB) gene; the most common mutation is expansion of a dodecamer repeat near the promoter. The authors studied a five-generation Arab family with ULD lacking photosensitivity. METHODS: An Arab family from the Galilee region of Israel with progressive myoclonus epilepsy was clinically evaluated. Blood samples were obtained from three living affected and 16 unaffected individuals. Expansion of dodecamer repeat in the CSTB gene was examined. RESULTS: The three living affected individuals showed spontaneous and action myoclonus, ataxia, and mild dementia. EEG in two individuals showed generalized polyspike-wave without photosensitivity. The family structure with large sibships and multiple consanguineous loops allowed the authors to examine the gene over four generations of adults. The three living affected individuals were homozygous for repeat expansions and 11 of the 16 unaffected family members were heterozygous. Instability was demonstrated by the presence of expansions of different sizes occurring on the same haplotype background in this inbred family. Fragment size variations could be unequivocally detected in two sibships. The expansions were in the 49 to 54 dodecamer repeat range. Changes in one generation were small, 1 to 4 repeat units, consisting of either enlargements or contractions. CONCLUSIONS: Instability of the expanded dodecamer repeats in the cystatin B gene is frequent. Almost invariably, a small change is observed in parent-child transmission. The lack of photosensitivity in this family is unexplained.


Assuntos
Árabes/genética , Cistatinas/genética , Repetições de Microssatélites/genética , Síndrome de Unverricht-Lundborg/genética , Adulto , Cistatina B , Análise Mutacional de DNA , Feminino , Genes Dominantes , Humanos , Endogamia , Israel , Masculino , Pessoa de Meia-Idade , Linhagem , Regiões Promotoras Genéticas , Síndrome de Unverricht-Lundborg/diagnóstico
11.
J Neurol Sci ; 190(1-2): 17-20, 2001 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11574101

RESUMO

APOE epsilon4 allele is associated with poorer outcome in degenerative neurological diseases. Its role in amyotrophic lateral sclerosis (ALS) is still unclear. The aim of the present study was to further analyze the association of APOE epsilon4 allele with progression and survival of ALS. One hundred consecutive ALS patients (53 males) and 133 controls were genotyped for the APOE epsilon4 allele. The association of this allele with survival to death or tracheostomy was analyzed by Kaplan-Meier survival analysis. The frequency of the APOE epsilon4 allele in ALS patients was slightly higher (15.1%) than in the control group (10.9%). Patients with or without an APOE epsilon4 allele had a similar age of onset and frequency of bulbar onset. There was a significant shortening of the 50% probability of survival (by 32 months) in patients carrying the APOE epsilon4 allele (p=0.03). In conclusion, carrying an APOE epsilon4 allele is a poor prognostic factor in ALS. This is compatible with a role of apolipoprotein on neuronal survival and repair.


Assuntos
Esclerose Lateral Amiotrófica/genética , Apolipoproteínas E/genética , Sobrevida/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Esclerose Lateral Amiotrófica/fisiopatologia , Apolipoproteína E4 , Análise Mutacional de DNA , Progressão da Doença , Feminino , Frequência do Gene/genética , Predisposição Genética para Doença , Testes Genéticos , Genótipo , Humanos , Israel , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Taxa de Sobrevida
12.
Biochem Biophys Res Commun ; 287(1): 92-7, 2001 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-11549258

RESUMO

AMP-activated protein kinase (AMPK), a heterotrimeric serine/threonine kinase, is activated by conditions leading to an increase of the intracellular AMP:ATP ratio. However, how AMPK is regulated under the oxidative stress is completely unknown. In the present study, we examined effects of the oxidative agent H(2)O(2) on AMPK. AMPK was transiently and concentration-dependently activated by H(2)O(2) in NIH-3T3 cells. This activation was tightly associated with an increased AMP:ATP ratio, an electrophoretic mobility shift of AMPK alpha1 catalytic subunit, and an increased phosphorylation level of AMPK alpha1 threonine 172, which is a major in vitro phosphorylation site by the upstream AMPK kinase. All of these events were significantly blocked by the pretreatment of 0.5% dimethyl sulfoxide, a potent hydroxyl radical scavenger, indicating that AMPK cascades are highly sensitive to the oxidative stress. Interestingly, a specific tyrosine kinase inhibitor, genistein, further stimulated the H(2)O(2)-induced AMPK activity by 70% without altering the AMP:ATP. Taken together, our results suggest that AMP:ATP ratio is the major parameter to which AMPK responds under the oxidative stress, but AMPK may be regulated in part by a tyrosine kinase-dependent pathway, which is independent of the cellular adenosine nucleotides level.


Assuntos
Peróxido de Hidrogênio/farmacologia , Complexos Multienzimáticos/metabolismo , Estresse Oxidativo/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Células 3T3 , Proteínas Quinases Ativadas por AMP , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Catálise , Ativação Enzimática/efeitos dos fármacos , Camundongos , Fosforilação/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Treonina/metabolismo
13.
J Biol Chem ; 276(42): 38349-52, 2001 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-11533044

RESUMO

The serine-threonine kinase Akt, also known as protein kinase B (PKB), is an important effector for phosphatidylinositol 3-kinase signaling initiated by numerous growth factors and hormones. Akt2/PKBbeta, one of three known mammalian isoforms of Akt/PKB, has been demonstrated recently to be required for at least some of the metabolic actions of insulin (Cho, H., Mu, J., Kim, J. K., Thorvaldsen, J. L., Chu, Q., Crenshaw, E. B., Kaestner, K. H., Bartolomei, M. S., Shulman, G. I., and Birnbaum, M. J. (2001) Science 292, 1728-1731). Here we show that mice deficient in another closely related isoform of the kinase, Akt1/PKBalpha, display a conspicuous impairment in organismal growth. Akt1(-/-) mice demonstrated defects in both fetal and postnatal growth, and these persisted into adulthood. However, in striking contrast to Akt2/PKBbeta null mice, Akt1/PKBalpha-deficient mice are normal with regard to glucose tolerance and insulin-stimulated disposal of blood glucose. Thus, the characterization of the Akt1 knockout mice and its comparison to the previously reported Akt2 deficiency phenotype reveals the non-redundant functions of Akt1 and Akt2 genes with respect to organismal growth and insulin-regulated glucose metabolism.


Assuntos
Glucose/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Proto-Oncogênicas , Alelos , Animais , Glicemia/metabolismo , Southern Blotting , Fibroblastos/metabolismo , Genótipo , Heterozigoto , Camundongos , Camundongos Knockout , Fenótipo , Fosfatidilinositol 3-Quinases/metabolismo , Isoformas de Proteínas , Proteínas Proto-Oncogênicas c-akt , Radioimunoensaio , Fatores Sexuais , Transdução de Sinais , Fatores de Tempo
15.
Mol Cell Biol ; 21(15): 5276-85, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11438681

RESUMO

In 3T3-L1 adipocytes, both insulin and endothelin 1 stimulate glucose transport via translocation of the GLUT4 glucose carrier from an intracellular compartment to the cell surface. Yet it remains uncertain as to whether both hormones utilize identical pathways and to what extent each depends on the heterotrimeric G protein Galphaq as an intermediary signaling molecule. In this study, we used a novel inducible system to rapidly and synchronously activate expression of a dominant inhibitory form of ADP-ribosylation factor 6, ARF6(T27N), in 3T3-L1 adipocytes and assessed its effects on insulin- and endothelin-stimulated hexose uptake. Expression of ARF6(T27N) in 3T3-L1 adipocytes was without effect on the ability of insulin to stimulate either 2-deoxyglucose uptake or the translocation of GLUT4 or GLUT1 to the plasma membrane. However, the same ARF6 inhibitory mutant blocked the stimulation of hexose uptake and GLUT4 translocation in response to either endothelin 1 or an activated form of Galphaq, Galphaq(Q209L). These results suggest that endothelin stimulates glucose transport through a pathway that is distinct from that utilized by insulin but is likely to depend on both a heterotrimeric G protein from the Gq family and the small G protein ARF6. These data are consistent with the interpretation that endothelin and insulin stimulate functionally different pools of glucose transporters to be redistributed to the plasma membrane.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Fatores de Ribosilação do ADP/fisiologia , Adipócitos/metabolismo , Endotelina-1/metabolismo , Glucose/farmacocinética , Insulina/metabolismo , Proteínas Musculares , Células 3T3 , Fator 6 de Ribosilação do ADP , Fatores de Ribosilação do ADP/genética , Adenoviridae/genética , Animais , Northern Blotting , Membrana Celular/metabolismo , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Endotelinas/metabolismo , Ativação Enzimática , Genes Dominantes , Transportador de Glucose Tipo 1 , Transportador de Glucose Tipo 4 , Camundongos , Proteínas de Transporte de Monossacarídeos/metabolismo , Mutação , Plasmídeos/metabolismo , Transporte Proteico , Retroviridae/metabolismo
16.
Science ; 292(5522): 1728-31, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11387480

RESUMO

Glucose homeostasis depends on insulin responsiveness in target tissues, most importantly, muscle and liver. The critical initial steps in insulin action include phosphorylation of scaffolding proteins and activation of phosphatidylinositol 3-kinase. These early events lead to activation of the serine-threonine protein kinase Akt, also known as protein kinase B. We show that mice deficient in Akt2 are impaired in the ability of insulin to lower blood glucose because of defects in the action of the hormone on liver and skeletal muscle. These data establish Akt2 as an essential gene in the maintenance of normal glucose homeostasis.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Glucose/metabolismo , Resistência à Insulina , Insulina/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Animais , Glicemia/metabolismo , Desoxiglucose/metabolismo , Feminino , Marcação de Genes , Técnica Clamp de Glucose , Teste de Tolerância a Glucose , Homeostase , Insulina/administração & dosagem , Insulina/sangue , Resistência à Insulina/genética , Resistência à Insulina/fisiologia , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/fisiologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais
17.
Nat Cell Biol ; 3(6): 596-601, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11389445

RESUMO

The initiation factor 4E for eukaryotic translation (eIF4E) binds the messenger RNA 5'-cap structure and is important in the regulation of protein synthesis. Mammalian eIF4E activity is inhibited when the initiation factor binds to the translational repressors, the 4E-binding proteins (4E-BPS). Here we show that the Drosophila melanogaster 4E-BP (d4E-BP) is a downstream target of the phosphatidylinositol-3-OH kinase (PI(3)K) signal-transduction cascade, which affects the interaction of d4E-BP with eIF4E. Ectopic expression of a highly active d4E-BP mutant in wing-imaginal discs causes a reduction of wing size, brought about by a decrease in cell size and number. A marked reduction in cell size was also observed in post-mitotic cells. Expression of d4E-BP in the eye and wing together with PI(3)K or dAkt1, the serine/threonine kinase downstream of PI(3)K, resulted in suppression of the growth phenotype elicited by these kinases. Our results support a role for d4E-BP as an effector of cell growth.


Assuntos
Proteínas de Transporte/fisiologia , Drosophila melanogaster/metabolismo , Fosfatidilinositol 3-Quinases/fisiologia , Fosfoproteínas/fisiologia , Transdução de Sinais/fisiologia , Sequência de Aminoácidos , Animais , Proteínas de Transporte/química , Proteínas de Transporte/genética , Divisão Celular/fisiologia , Clonagem Molecular , Proteínas de Drosophila , Drosophila melanogaster/citologia , Drosophila melanogaster/enzimologia , Peptídeos e Proteínas de Sinalização Intracelular , Dados de Sequência Molecular , Fatores de Iniciação de Peptídeos , Fosfoproteínas/química , Fosfoproteínas/genética , Biossíntese de Proteínas , Homologia de Sequência de Aminoácidos
18.
Mol Cell ; 7(5): 1085-94, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11389854

RESUMO

Eukaryotic cells possess systems for sensing nutritional stress and inducing compensatory mechanisms that minimize the consumption of ATP while utilizing alternative energy sources. Such stress can also be imposed by increased energy needs, such as in skeletal muscle of exercising animals. In these studies, we consider the role of the metabolic sensor, AMP-activated protein kinase (AMPK), in the regulation of glucose transport in skeletal muscle. Expression in mouse muscle of a dominant inhibitory mutant of AMPK completely blocked the ability of hypoxia or AICAR to activate hexose uptake, while only partially reducing contraction-stimulated hexose uptake. These data indicate that AMPK transmits a portion of the signal by which muscle contraction increases glucose uptake, but other AMPK-independent pathways also contribute to the response.


Assuntos
Hipóxia/fisiopatologia , Complexos Multienzimáticos/fisiologia , Contração Muscular/fisiologia , Proteínas Serina-Treonina Quinases/fisiologia , Proteínas Quinases Ativadas por AMP , Animais , Transporte Biológico Ativo/efeitos dos fármacos , Transporte Biológico Ativo/fisiologia , Ativação Enzimática/efeitos dos fármacos , Glucose/metabolismo , Hipóxia/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Músculo Esquelético/enzimologia , Miocárdio/enzimologia , Fosforilação/efeitos dos fármacos , Transdução de Sinais
20.
Prehosp Disaster Med ; 16(1): 46-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11367941

RESUMO

INTRODUCTION: Change must begin with education. Theme 8 explored issues that need attention in Disaster Medicine education. METHODS: Details of the methods used are provided in the introductory paper. The chairs moderated all presentations and produced a summary that was presented to an assembly of all of the delegates. The chairs then presided over a workshop that resulted in the generation of a set of action plans that then were reported to the collective group of all delegates. RESULTS: Main points developed during the presentations and discussion included: (1) formal education, (2) standardized definitions, (3) integration, (4) evaluation of programs and interventions, (5) international cooperation, (6) identifying the psychosocial consequences of disaster, (7) meaningful research, and (8) hazard, impact, risk and vulnerability analysis. DISCUSSION: Three main components of the action plans were identified as evaluation, research, and education. The action plans recommended that: (1) education on disasters should be formalized, (2) evaluation of education and interventions must be improved, and (3) meaningful research should be promulgated and published for use at multiple levels and that applied research techniques be the subject of future conferences. CONCLUSIONS: The one unanimous conclusion was that we need more and better education on the disaster phenomenon, both in its impacts and in our response to them. Such education must be increasingly evidence-based.


Assuntos
Planejamento em Desastres/organização & administração , Medicina de Emergência/educação , Avaliação das Necessidades/organização & administração , Competência Clínica/normas , Saúde Global , Planejamento em Saúde/organização & administração , Pesquisa sobre Serviços de Saúde , Humanos , Relações Interinstitucionais , Cooperação Internacional , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde , Pesquisa , Medição de Risco
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