Assuntos
Humanos , Masculino , Pré-Escolar , Sinusite/complicações , Sinusite/diagnóstico por imagem , Seio Cavernoso/diagnóstico por imagem , Trombose do Corpo Cavernoso/diagnóstico , Trombose do Corpo Cavernoso/etiologia , Trombose do Corpo Cavernoso/terapia , Streptococcus constellatus/isolamento & purificação , Tomografia Computadorizada por Raios X , Anti-Infecciosos/uso terapêutico , Anticoagulantes/uso terapêuticoAssuntos
Humanos , Masculino , Pré-Escolar , Síndrome de Resposta Inflamatória Sistêmica/diagnóstico , Síndrome de Resposta Inflamatória Sistêmica/terapia , COVID-19/complicações , COVID-19/diagnóstico , Pulmão/diagnóstico por imagem , Radiografia , Tomografia Computadorizada por Raios X , Cuidados CríticosRESUMO
Hepatocyte nuclear factor 4alpha (HNF4alpha) is essential for the establishment and maintenance of liver-specific gene expression. The HNF4alpha gene codes for several isoforms whose developmental and physiological relevance has not yet been explored. HNF4alpha1 and HNF4alpha7 originate from different promoters, while alternative splicing in 3' leads to HNF4alpha2 and HNF4alpha8, respectively. HNF4alpha7/alpha8 were abundantly expressed in embryonic liver and fetal-like hepatoma cells. HNF4alpha1/alpha2 transcripts were up-regulated at birth and represented the only isoforms in adult-like hepatoma cells. In line with its expression profile, HNF4alpha7 activated more avidly than HNF4alpha1 reporter plasmids for genes that are expressed early. The expression patterns of both isoforms together with the differences observed in their transcriptional activities provide elements accounting for fine-tuning of the activity of HNF4alpha. The sequential expression of HNF4alpha7/alpha8 and HNF4alpha1/alpha2 during mouse liver development is the only modification in liver-enriched transcription factors thus far recorded, which parallels the transition from the fetal to the adult hepatic phenotype.
Assuntos
Proteínas de Ligação a DNA , Fígado/embriologia , Fosfoproteínas/biossíntese , Fosfoproteínas/química , Splicing de RNA , Fatores de Transcrição/biossíntese , Fatores de Transcrição/química , Células 3T3 , Processamento Alternativo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Northern Blotting , Western Blotting , Carcinoma Hepatocelular/metabolismo , Linhagem Celular , Dimerização , Éxons , Genes Reporter , Fator 4 Nuclear de Hepatócito , Fígado/metabolismo , Camundongos , Modelos Genéticos , Fenótipo , Plasmídeos/metabolismo , Regiões Promotoras Genéticas , Isoformas de Proteínas , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Transcrição Gênica , Ativação Transcricional , TransfecçãoRESUMO
We have characterized a 700 bp enhancer element around -6 kb relative to the HNF4alpha1 transcription start. This element increases activity and confers glucocorticoid induction to a heterologous as well as the homologous promoters in differentiated hepatoma cells and is transactivated by HNF4alpha1, HNF4alpha7, HNF1alpha and HNF1beta in dedifferentiated hepatoma cells. A 240 bp sub-region conserves basal and hormone-induced enhancer activity. It contains HNF1, HNF4, HNF3 and C/EBP binding sites as shown by DNase I footprinting and electrophoretic mobility shift assays using nuclear extracts and/or recombinant HNF1alpha and HNF4alpha1. Mutation analyses showed that the HNF1 site is essential for HNF1alpha transactivation and is required for full basal enhancer activity, as is the C/EBP site. Glucocorticoid response element consensus sites which overlap the C/EBP, HNF4 and HNF3 sites are crucial for optimal hormonal induction. We present a model that accounts for weak expression of HNF4alpha1 in the embryonic liver and strong expression in the newborn/adult liver via the binding sites identified in the enhancer.
Assuntos
Elementos Facilitadores Genéticos/genética , Glucocorticoides/farmacologia , Fosfoproteínas/genética , Regiões Promotoras Genéticas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/fisiologia , Animais , Sequência de Bases , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Sítios de Ligação/genética , Proteína alfa Estimuladora de Ligação a CCAAT/metabolismo , Cloranfenicol O-Acetiltransferase/genética , Cloranfenicol O-Acetiltransferase/metabolismo , Proteínas de Ligação a DNA/metabolismo , Dexametasona/farmacologia , Elementos Facilitadores Genéticos/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Fator 1 Nuclear de Hepatócito , Fator 1-alfa Nuclear de Hepatócito , Fator 1-beta Nuclear de Hepatócito , Fator 3-alfa Nuclear de Hepatócito , Fator 4 Nuclear de Hepatócito , Fígado/metabolismo , Luciferases/genética , Luciferases/metabolismo , Camundongos , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Plasmídeos/genética , Ligação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Sequências Reguladoras de Ácido Nucleico/genética , Sequências Reguladoras de Ácido Nucleico/fisiologia , Fatores de Transcrição/metabolismo , Transcrição Gênica , Células Tumorais CultivadasRESUMO
In rat-1 fibroblasts stably expressing alpha1d-adrenoceptors BMY 7378, phentolamine, chloroethylclonidine and 5-methyl urapidil decreased basal [Ca2+]i. WB 4101 induced a very small effect on this parameter but when added before the other antagonists it blocked their effect. All these agents inhibited the action of norepinephrine. Phorbol myristate acetate also blocked the effect of norepinephrine and decreased basal [Ca2+]i. Staurosporine inhibited these effects of the phorbol ester. Our results suggest that: (1) alpha1d-adrenoceptors exhibit spontaneous ligand-independent activity, (2) BMY 7378, phentolamine, chloroethylclonidine and 5-methyl urapidil act as inverse agonists and (3) protein kinase C activation blocks spontaneous and agonist-stimulated alpha1d-adrenoceptor activity.
Assuntos
Agonistas alfa-Adrenérgicos/farmacologia , Antagonistas Adrenérgicos alfa/farmacologia , Cálcio/metabolismo , Receptores Adrenérgicos alfa 1/fisiologia , Acetato de Tetradecanoilforbol/farmacologia , Agonistas de Receptores Adrenérgicos alfa 1 , Antagonistas de Receptores Adrenérgicos alfa 1 , Animais , Linhagem Celular , Clonidina/análogos & derivados , Clonidina/farmacologia , Dioxanos/farmacologia , Relação Dose-Resposta a Droga , Endotelina-1/farmacologia , Fibroblastos , Norepinefrina/farmacologia , Fentolamina/farmacologia , Piperazinas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/fisiologia , Ratos , Estaurosporina/farmacologia , TransfecçãoRESUMO
The action of bradykinin was studied in rat-1 fibroblasts stably expressing alpha1b-adrenoceptors. It was observed that bradykinin and kallidin markedly increase cytosol calcium concentration, but that the B1 agonist, des-Arg9-bradykinin, only mimicked this effect to a minimal extent. Antagonists, selective for the B2 subtype, such as Hoe 140, blocked this effect of bradykinin and kallidin. Similarly, bradykinin and kallidin stimulated the production of inositol phosphates and B2 antagonists blocked their actions. The possibility that bradykinin could modulate alpha1b-adrenoceptors was studied. It was observed that bradykinin and kallidin increased alpha1b-adrenoceptor phosphorylation and that such effect was also blocked by Hoe 140. Interestingly, the ability of norepinephrine to increase intracellular calcium concentration was not altered by pretreatment of the cells with bradykinin, i.e. bradykinin induced alpha1b-adrenoceptor phosphorylation but this did not lead to receptor desensitization.
