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1.
Nord J Psychiatry ; : 1-5, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31686565

RESUMO

Background: Patients with co-occurring Attention-Deficit/Hyperactivity Disorder (ADHD) and ASD might benefit from stimulants. There is a progressive increase in prescribing ADHD aimed medications for children diagnosed with Autism Spectrum Disorder (ASD), despite scarce knowledge and no distinct clinical guidelines for that matter.Aim: This study aims to analyze the effect of stimulant on processing speed performance and attention indices in children with ASD and ADHD.Methods: Forty children aged 6-18 years diagnosed with ASD who also met the criteria for ADHD were recruited. All children performed a computerized performance test for the assessment of cognitive attention performance three times: twice while they are drug naïve and once an hour after taking a single dose of 10 mg. methylphenidate (MPH). This performance was compared to a group of children diagnosed with 'ADHD only' without ASD.Results: A significant difference (p < 0.001) was found only in the parameter of measuring cognitive processing speed. This effect is significantly different from the response of the 'ADHD only' group.Conclusions: The reaction to MPH among ASD children is different than among ADHD children. In ASD, MPH significantly improved cognitive processing speed without changing other measured attention parameters. Improving processing speed, might improve every day functioning in children with ASD who also met the criteria for ADHD, in other means than expected. This unique response suggests new research targets for treatment with stimulants in ASD and ADHD children and its influence on cognitive parameters.

3.
Genome Med ; 11(1): 12, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30819258

RESUMO

BACKGROUND: Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity). METHODS: Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes. RESULTS: We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances. CONCLUSIONS: TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.


Assuntos
Anormalidades Craniofaciais/genética , Deficiências do Desenvolvimento/genética , Mutação INDEL , Deficiência Intelectual/genética , Hipotonia Muscular/genética , Síndrome de Smith-Magenis/genética , Fatores de Transcrição/genética , Adolescente , Criança , Pré-Escolar , Anormalidades Craniofaciais/patologia , Deficiências do Desenvolvimento/patologia , Feminino , Humanos , Lactente , Deficiência Intelectual/patologia , Masculino , Hipotonia Muscular/patologia , Síndrome de Smith-Magenis/patologia , Fatores de Transcrição/metabolismo , Adulto Jovem
4.
Mol Autism ; 10: 2, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30728928

RESUMO

Background: The endocannabinoid system (ECS) is a major regulator of synaptic plasticity and neuromodulation. Alterations of the ECS have been demonstrated in several animal models of autism spectrum disorder (ASD). In some of these models, activating the ECS rescued the social deficits. Evidence for dysregulations of the ECS in human ASD are emerging, but comprehensive assessments and correlations with disease characteristics have not been reported yet. Methods: Serum levels of the main endocannabinoids, N-arachidonoylethanolamine (AEA or anandamide) and 2-arachidonoylglycerol (2-AG), and their related endogenous compounds, arachidonic acid (AA), N-palmitoylethanolamine (PEA), and N-oleoylethanolamine (OEA), were analyzed by liquid chromatography/tandem mass spectrometry in 93 children with ASD (age = 13.1 ± 4.1, range 6-21; 79% boys) and 93 age- and gender-matched neurotypical children (age = 11.8 ± 4.3, range 5.5-21; 79% boys). Results were associated with gender and use of medications, and were correlated with age, BMI, and adaptive functioning of ASD participants as reflected by scores of Autism Diagnostic Observation Schedule (ADOS-2), Vineland Adaptive Behavior Scale-II (VABS-II), and Social Responsiveness Scale-II (SRS-2). Results: Children with ASD had lower levels (pmol/mL, mean ± SEM) of AEA (0.722 ± 0.045 vs. 1.252 ± 0.072, P < 0.0001, effect size 0.91), OEA (17.3 ± 0.80 vs. 27.8 ± 1.44, P < 0.0001, effect size 0.94), and PEA (4.93 ± 0.32 vs. 7.15 ± 0.37, P < 0.0001, effect size 0.65), but not AA and 2-AG. Serum levels of AEA, OEA, and PEA were not significantly associated or correlated with age, gender, BMI, medications, and adaptive functioning of ASD participants. In children with ASD, but not in the control group, younger age and lower BMI tended to correlate with lower AEA levels. However, these correlations were not statistically significant after a correction for multiple comparisons. Conclusions: We found lower serum levels of AEA, PEA, and OEA in children with ASD. Further studies are needed to determine whether circulating endocannabinoid levels can be used as stratification biomarkers that identify clinically significant subgroups within the autism spectrum and if they reflect lower endocannabinoid "tone" in the brain, as found in animal models of ASD.


Assuntos
Transtorno do Espectro Autista/sangue , Endocanabinoides/sangue , Adolescente , Biomarcadores/sangue , Estudos de Casos e Controles , Criança , Feminino , Humanos , Masculino , Ensaios Clínicos Controlados Aleatórios como Assunto , Adulto Jovem
5.
J Autism Dev Disord ; 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-30382443

RESUMO

Anecdotal evidence of successful cannabis treatment in autism spectrum disorder (ASD) are accumulating but clinical studies are lacking. This retrospective study assessed tolerability and efficacy of cannabidiol-rich cannabis, in 60 children with ASD and severe behavioral problems (age = 11.8 ± 3.5, range 5.0-17.5; 77% low functioning; 83% boys). Efficacy was assessed using the Caregiver Global Impression of Change scale. Adverse events included sleep disturbances (14%) irritability (9%) and loss of appetite (9%). One girl who used higher tetrahydrocannabinol had a transient serious psychotic event which required treatment with an antipsychotic. Following the cannabis treatment, behavioral outbreaks were much improved or very much improved in 61% of patients. This preliminary study supports feasibility of CBD-based cannabis trials in children with ASD.

6.
J Atten Disord ; 22(14): 1333-1343, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25791438

RESUMO

OBJECTIVE: This study investigated age-related changes in sustained attention in children with ADHD and in their typically developed peers. METHOD: The study used a Continuous Performance Test (CPT) that includes visual and auditory stimuli serving as distractors. The rate of omission errors was used as a measurement of difficulty in sustained attention. Participants were children and adolescents aged 7 to 18 years (478 with ADHD and 361 without ADHD). RESULTS: Both groups of adolescents (with and without ADHD) showed reduced distractibility than younger children from the same group. However, distractibility tended to diminish in non-ADHD adolescents, but not in adolescents with ADHD. CONCLUSION: Although part of the difficulties in ADHD could be explained by developmental delay that improves with time, other deficits, such as increased distractibility causing more omission errors, do not show a clear developmental trajectory. The results suggest that deficits in inhibitory control might be the core of ADHD.

7.
Arch Clin Neuropsychol ; 32(1): 81-93, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28122767

RESUMO

OBJECTIVE: Despite the popularity of continuous performance tests (CPT) in supporting the diagnostic procedure of attention-deficit hyperactivity disorder (ADHD), these measures are still controversial mainly due to limited sensitivity, specificity, and ecological validity. Thus, there continues to be a need for further validation of these objective attention measures. The purpose of this study was to evaluate the usefulness of a CPT that includes environmental distracting stimuli, in supporting the diagnosis of ADHD in children. METHOD: Participants were 798 children aged 7-12 years (493 boys and 305 girls). The ADHD group included 339 children, whereas the control group included 459 children without ADHD. The study employed the MOXO-CPT, which incorporates visual and auditory stimuli serving as environmental distractors. RESULTS: Compared to their unaffected peers, children with ADHD received significantly lower scores in all 4 CPT indices: attention, timing, hyperactivity, and impulsivity. Specifically, ADHD children were less attended to the stimuli and performed fewer reactions on accurate timing. Furthermore, children with ADHD performed significantly more impulsive and hyperactive responses than controls. Receiver operating characteristic analysis revealed fair to excellent diagnostic ability of all CPT indices except impulsivity, which showed poor ability to distinguish ADHD children from controls. The test's total score yielded excellent diagnostic performance. CONCLUSIONS: MOXO-CPT consistently distinguished between children with ADHD and their unaffected peers, so that children with ADHD performed worse than controls in all study indices. Integration of CPT indices improves the diagnostic capacity of ADHD and may better reflect the complexity and heterogeneity of ADHD.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Testes Neuropsicológicos , Valor Preditivo dos Testes , Atenção , Estudos de Casos e Controles , Criança , Feminino , Humanos , Masculino
8.
J Neurosci Methods ; 222: 62-8, 2014 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-24211249

RESUMO

BACKGROUND: Diagnosis of ADHD in adolescents involves specific challenges. Conventional CPT's may fail to consistently distinguish ADHD from non-ADHD due to insufficient cognitive demands. The aim of this study was to explore whether the incorporation of environmental distractors into a CPT would increase its ability to distinguish ADHD from non-ADHD adolescents. NEW METHOD: Using the rate of omission errors as a measure of difficulty in sustained attention, this study examined whether ADHD adolescents are more distracted than controls and which type of distractors is more effective in terms of ADHD diagnosis. The study employed the MOXO-CPT version which includes visual and auditory stimuli serving as distractors. Participants were 176 adolescents aged 13-18 years, 133 diagnosed with ADHD and 43 without ADHD. RESULTS AND COMPARISON WITH EXISTING METHODS: Results showed that ADHD adolescents produced significantly more omission errors in the presence of pure visual distractors and the combination of visual and auditory distractors than in no-distractors conditions. Distracting stimuli had no effect on CPT performance of non-ADHD adolescents. ROC analysis further demonstrated that the mere presence of distractors improved the utility of the test. CONCLUSIONS: This study provides evidence that incorporation of environmental distractors into a CPT is useful in term of ADHD diagnosis. ADHD adolescents were more distracted than controls by all types of environmental distractors. ADHD adolescents were more distracted by pure visual distractors and by the combination of distractors than by pure auditory ones.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Atenção , Testes Neuropsicológicos , Estimulação Acústica , Adolescente , Feminino , Humanos , Masculino , Estimulação Luminosa , Curva ROC , Análise e Desempenho de Tarefas
9.
Front Hum Neurosci ; 7: 805, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24319423

RESUMO

This study examined the effect of the incorporation of environmental distractors in computerized continuous performance test (CPT) on the ability of the test in distinguishing ADHD from non-ADHD children. It was hypothesized that children with ADHD would display more distractibility than controls while performing CPT as measured by omission errors in the presence of pure visual, pure auditory, and a combination of visual and auditory distracting stimuli. Participants were 663 children aged 7-12 years, of them 345 diagnosed with ADHD and 318 without ADHD. Results showed that ADHD children demonstrated more omission errors than their healthy peers in all CPT conditions (no distractors, pure visual or auditory distractors and combined distractors). However, ADHD and non-ADHD children differed in their reaction to distracting stimuli; while all types of distracting stimuli increased the rate of omission errors in ADHD children, only combined visual and auditory distractors increased it in non-ADHD children. Given the low ecological validity of many CPT, these findings suggest that incorporating distractors in CPT improves the ability to distinguish ADHD from non-ADHD children.

10.
Front Hum Neurosci ; 7: 691, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24298243

RESUMO

While data from behavioral, neuropsychological, and brain studies suggested that Attention-Deficit/Hyperactivity Disorder (ADHD) is related to a developmental lag that reduces with age, other studies have proposed that ADHD represents a deviant brain function. The present study used a cross-sectional approach to examine whether ADHD children show a developmental delay in cognitive performance measured by continuous performance test (CPT). We thus, compared six age groups of ADHD children (N = 559) and their unaffected peers (N = 365), aged 6-11, in four parameters of MOXO-CPT performance: Attention, Timing, Hyperactivity and Impulsivity. Results have shown that despite improvement in CPT performance with age, ADHD children continued to demonstrate impaired performance as compared to controls. In most parameters, CPT performance of ADHD children matched that of 1-3 years younger normal controls, with a delay most prominent in older children. However, in the Hyperactivity parameter, ADHD children's performance resembled that of much younger healthy children, with almost no evidence for a developmental catch up. This study suggests that while some cognitive functions develop slower but normally, other functions (e.g., inhibitory control) show a different trajectory.

11.
Pediatr Res ; 73(1): 111-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23085818

RESUMO

BACKGROUND: A vitamin B(1)-deficient soy-based infant formula was marketed in Israel in 2003, exposing infants to clinical or subclinical B(1) deficiency. We investigated whether subclinical B(1) deficiency in early infancy had medical, neurodevelopmental, or cognitive effects at 3-5 y of age. METHODS: A historical prospective cohort study was conducted consisting of four groups: "exposed," consuming a B(1)-deficient soy-based formula exclusively for four consecutive weeks or longer; "control," consuming no soy-based formula; "mixed," consuming the formula nonexclusively or exclusively for less than four consecutive weeks; and "other," consuming soy-based formulas other than Remedia. Participants were evaluated by medical examination, Stanford-Binet (SB) intelligence test, sensory profile evaluation, and Conners scales (attention deficit disorder/attention deficit and hyperactivity disorder (ADD/ADHD)). RESULTS: Following adjustment for gender, age, and maternal education, there were no significant differences among the four groups on the mean SB scores, on the verbal and nonverbal scores, or in the proportion of children in each group with scores <90. A significantly higher proportion of exposed children as compared with control children had an impaired sensory profile and scores on the Conners scales (ADD/ADHD), but these proportions were also high in the "other" and "mixed" groups. CONCLUSION: The results do not support an association between subclinical B(1) deficiency in infancy and long-term development.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Desenvolvimento Infantil/fisiologia , Fórmulas Infantis/química , Deficiência de Tiamina/complicações , Deficiência de Tiamina/patologia , Fatores Etários , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Fórmulas Infantis/administração & dosagem , Recém-Nascido , Testes de Inteligência , Masculino , Estudos Prospectivos , Fatores Sexuais , Deficiência de Tiamina/induzido quimicamente
13.
J Biol Chem ; 280(40): 33873-84, 2005 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-16100117

RESUMO

The hepatic transcriptional regulation by glucocorticoids of the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK-C) gene is coordinated by interactions of specific transcription factors at the glucocorticoid regulatory unit (GRU). We propose an extended GRU that consists of four accessory sites, two proximal AF1 and AF2 sites and their distal counterpart dAF1 (-993) and a new site, dAF2 (-1365); together, these four sites form a palindrome. Sequencing and gel shift binding assays of hepatic nuclear proteins interacting with these sites indicated similarity of dAF1 and dAF2 sites to the GRU proximal AF1 and AF2 sites. Chromatin immunoprecipitation assays demonstrated that glucocorticoids enhanced the binding of FOXO1 and peroxisome proliferator-activated receptor-alpha to AF2 and dAF2 sites and not to dAF1 site but enhanced the binding of hepatic nuclear transcription factor-4alpha only to the dAF1 site. Insulin inhibited the binding of these factors to their respective sites but intensified the binding of phosphorylated FOXO1. Transient transfections in HepG2 human hepatoma cells showed that glucocorticoid receptor interacts with several non-steroid nuclear receptors, yielding a synergistic response of the PEPCK-C gene promoter to glucocorticoids. The synergistic stimulation by glucocorticoid receptor together with peroxisome proliferator-activated receptor-alpha or hepatic nuclear transcription factor-4alpha requires all four accessory sites, i.e. a mutation of each of these markedly affects the synergistic response. Mice with a targeted mutation of the dAF1 site confirmed this requirement. This mutation inhibited the full response of hepatic PEPCK-C gene to diabetes by reducing PEPCK-C mRNA level by 3.5-fold and the level of circulating glucose by 25%.


Assuntos
Regulação da Expressão Gênica , Glucocorticoides/farmacologia , Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Receptores de Glucocorticoides/fisiologia , Animais , Carcinoma Hepatocelular/patologia , Cromatina/química , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/metabolismo , Hipoglicemiantes/farmacologia , Imunoprecipitação , Insulina/farmacologia , Fígado/enzimologia , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Transgênicos , Mutagênese Sítio-Dirigida , PPAR alfa , Regiões Promotoras Genéticas , Transcrição Genética , Transfecção , Células Tumorais Cultivadas
14.
Crit Rev Biochem Mol Biol ; 40(3): 129-54, 2005 May-Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15917397

RESUMO

Transcription of the gene for PEPCK-C occurs in a number of mammalian tissues, with highest expression occurring in the liver, kidney cortex, and white and brown adipose tissue. Several hormones and other factors, including glucagon, epinephrine, insulin, glucocorticoids and metabolic acidosis, control this process in three responsive tissues, liver, adipose tissue, and kidney cortex. Expression of the gene in these three tissues in regulated in a different manner, responding to the specific physiological role of the tissue. The PEPCK-C gene promoter has been extensively studied and a number of regulatory regions identified that bind key transcription factors and render the gene responsive to hormonal and dietary stimuli. This review will focus on the control of transcription for the gene, with special emphasis on our current understanding of the transcription factors that are involved in the response of PEPCK-C gene in specific tissues. We have also reviewed the biological function of PEPCK-C in each of the tissues discussed in this review, in order to place the control of PEPCK-C gene transcription in the appropriate physiological context. Because of its extraordinary importance in mammalian metabolism and its broad pattern of tissue-specific expression, the PEPCK-C gene has become a model for studying the biological basis of the control of gene transcription.


Assuntos
Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Transcrição Genética , Tecido Adiposo/metabolismo , Animais , Metabolismo Energético , Ácidos Graxos/metabolismo , Glucocorticoides/metabolismo , Humanos , Insulina/metabolismo , Rim/metabolismo , Fígado/metabolismo , Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Regiões Promotoras Genéticas
15.
Gene ; 318: 177-84, 2003 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-14585510

RESUMO

The transcription of the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK-C) gene is differentially regulated in each of the several PEPCK-C-expressing tissues. In the kidney, it is regulated by glucocorticoids and acidosis. Previously, we reported that in LLC-PK1 and derived kidney cell lines, mutation of the hepatic nuclear factor 1 (HNF-1) binding site in PEPCK-C gene promoter markedly reduced both the basal activity of the gene promoter and its response to acidic pH. Using the same kidney cell line, we now report that nuclear receptors robustly stimulate transcription from the PEPCK-C gene promoter. This stimulation is markedly reduced by mutation of the accessory factor 1 (AF1) site in the glucocorticoid responsive unit (GRU) residing within the glucocorticoid-responsive domain. The stimulation is likewise reduced by mutation of the HNF-1 site, residing outside the nuclear receptor-responsive domain of the PEPCK-C gene promoter. There is no binding similarity between HNF-1 and AF1 binding sites, as is evident from gel shift assays showing a lack of competition of either site for the binding of renal nuclear proteins to the other. We further assessed that the regulation of PEPCK-C gene transcription by acidosis is not mediated by nuclear receptors. This became evident from studies of transgenic mice harboring a rat PEPCK-C transgene driven by truncated 5' flanking region of the gene, which contains the HNF-1 site but lacks the glucocorticoid responsive domain. The full transcriptional response of this transgene to acidosis establishes that the truncated 5' flanking region (362 bp) of the PEPCK-C gene contains the information required for the acidosis-mediated regulation independent of the glucocorticoid domain. Taking together the previous and present results, it appears that acidosis and nuclear receptors regulate the renal transcription of the PEPCK-C gene via two independent domains in the 5' flanking region of the gene. These two modulations, as well as the basal activity of the gene, require intact HNF-1 binding site in the gene promoter.


Assuntos
Proteínas de Ligação a DNA , Rim/enzimologia , Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Fatores de Transcrição/metabolismo , Cloreto de Amônio/farmacologia , Animais , Sítios de Ligação/genética , Linhagem Celular , Ensaio de Desvio de Mobilidade Eletroforética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Fator 1 Nuclear de Hepatócito , Fator 1-alfa Nuclear de Hepatócito , Fator 1-beta Nuclear de Hepatócito , Concentração de Íons de Hidrogênio , Rim/metabolismo , Camundongos , Camundongos Transgênicos , Mutação , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Interferon/metabolismo , Sequências Reguladoras de Ácido Nucleico/genética , Fatores de Transcrição/genética , Transcrição Genética
17.
J Biol Chem ; 278(15): 12929-36, 2003 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-12560325

RESUMO

The cytosolic form of the phosphoenolpyruvate carboxykinase (PEPCK-C) gene is selectively expressed in several tissues, primarily in the liver, kidney, and adipose tissue. The transcription of the gene is reciprocally regulated by glucocorticoids in these tissues. It is induced in the liver and kidney but repressed in the white adipose tissue. To elucidate which adipocyte-specific transcription factors participate in the repression of the gene, DNase I footprinting analyses of nuclear proteins from 3T3-F442A adipocytes and transient transfection experiments in NIH3T3 cells were utilized. Glucocorticoid treatment slightly reduced the nuclear C/EBP alpha concentration but prominently diminished the binding of adipocyte-derived nuclear proteins to CCAAT/enhancer-binding protein (C/EBP) recognition sites, without affecting the binding to nuclear receptor sites in the PEPCK-C gene promoter. Of members of the C/EBP family of transcription factors, C/EBP alpha was the strongest trans-activator of the PEPCK-C gene promoter in the NIH3T3 cell line. The glucocorticoid receptor (GR), in the presence of its hormone ligand, inhibited the activation of the PEPCK-C gene promoter by C/EBP alpha or C/EBP beta but not by the adipocyte-specific peroxisome proliferator-activated receptor gamma 2. This inhibition effect was similar using the wild type or mutant GR and did not depend on GR binding to the DNA. The glucocorticoid response unit (GRU) in the PEPCK-C gene promoter (-2000 to +73) restrained C/EBP alpha-mediated trans-activation, because mutation of each single GRU element increased this activation by 3-4-fold. This series of GRU mutations were repressed by wild type GR to the same percent as was the nonmutated PEPCK-C gene promoter. In contrast, the repression by mutant GR depended on the intact AF1 site in the gene promoter, whereby mutation of the AF1 element abolished the repression.


Assuntos
Adipócitos/enzimologia , Proteínas Estimuladoras de Ligação a CCAAT/antagonistas & inibidores , Dexametasona/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glucocorticoides/farmacologia , Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Transcrição Genética/efeitos dos fármacos , Células 3T3 , Animais , Sequência de Bases , Diferenciação Celular , Pegada de DNA , Primers do DNA , Humanos , Camundongos , Regiões Promotoras Genéticas , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ativação Transcricional
18.
Proc Natl Acad Sci U S A ; 99(2): 625-30, 2002 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-11792850

RESUMO

Regulation of the turnover of triglycerides in adipose tissue requires the continuous provision of 3-glycerophosphate, which may be supplied by the metabolism of glucose or by glyceroneogenesis, the de novo synthesis of 3-glycerophosphate from sources other than hexoses or glycerol. The importance of glyceroneogenesis in adipose tissue was assessed in mice by specifically eliminating the expression of the cytosolic form of phosphoenolpyruvate carboxykinase (PEPCK-C), an enzyme that plays a pivotal role in the pathway. To accomplish this, we mutated the binding site for the peroxisome proliferator-activated receptor gamma (PPAR gamma) called the peroxisome proliferator-activated receptor element (PPARE), in the 5' flanking region of the PEPCK-C gene in the mouse by homologous recombination. The mutation abolished expression of the gene in white adipose tissue and considerably reduced its expression in brown adipose tissue, whereas the level of PEPCK-C mRNA in liver and kidney remained normal. Epididymal white adipose tissue from these mice had a reduced triglyceride deposition, with 25% of the animals displaying lipodystrophy. There was also a greatly reduced level of lipid accumulation in brown adipose tissue. A strong correlation between the hepatic content of triglycerides and the size of the epididymal fat pad in PPARE(-/-) mice suggests that hepatic triglyceride synthesis predominantly utilizes free fatty acids derived from the adipose tissue. Unlike other models, PPARE(-/-) mice with lipodystrophy did not exhibit the lipodystrophy-associated features of diabetes and displayed only moderate hyperglycemia. These studies establish the importance of the PPARE site for PEPCK-C gene expression in adipose tissue and the role of PEPCK-C in the regulation of glyceroneogenesis, a pathway critical for maintaining the deposition of triglycerides in adipose tissue.


Assuntos
Tecido Adiposo/anatomia & histologia , Tecido Adiposo/metabolismo , Mutação , Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Tecido Adiposo Marrom/anatomia & histologia , Tecido Adiposo Marrom/metabolismo , Animais , Sítios de Ligação/genética , Glicemia/genética , Glicemia/metabolismo , Citosol/enzimologia , Expressão Gênica , Metabolismo dos Lipídeos , Lipodistrofia/genética , Lipodistrofia/metabolismo , Lipodistrofia/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Triglicerídeos/metabolismo
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