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BACKGROUND: Inflammation is a key mediator in the development and progression of the atherosclerotic disease process as well as its resultant complications, like myocardial infarction (MI), stroke and cardiovascular (CV) death, and is emerging as a novel treatment target. Trials involving anti-inflammatory medications have demonstrated outcome benefit in patients with known CV disease. In this regard, colchicine appears to hold great promise. However, there are potential drawbacks to colchicine use, as some studies have identified an increased risk of infection, and a non-significant trend for increased all-cause mortality. Thus, a more thorough understanding of the underlying mechanism of action of colchicine is needed to enable a better patient selection for this novel CV therapy. OBJECTIVE: The primary objective of the Canadian Study of Arterial Inflammation in Patients with Diabetes and Recent Vascular Events, Evaluation of Colchicine Effectiveness (CADENCE) trial is to assess the effect of colchicine on vascular inflammation in the carotid arteries and ascending aorta measured with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in patients with type 2 diabetes mellitus (T2DM) or pre-diabetes who have experienced a recent vascular event (acute coronary syndrome (ACS)/MI, transient ischaemic attack (TIA) or stroke). Secondary objectives include determining colchicine's effect on inflammatory biomarkers (high-sensitivity C reactive protein (hs-CRP) and interleukin-6 (IL-6)). Additionally, we will assess if baseline inflammation imaging or biomarkers are associated with a treatment response to colchicine determined by imaging. Exploratory objectives will look at: (1) the difference in the inflammatory response to colchicine in patients with coronary events compared with patients with cerebral events; (2) the difference in the inflammatory response to colchicine in different vascular beds; (3) the relationship of FDG-PET imaging markers with serum biomarkers and (4) assessment of quality-of-life changes. METHODS AND DESIGN: CADENCE is a multicentre, prospective, randomised, double-blinded, placebo-controlled study to determine the effect of colchicine on arterial inflammation as assessed with imaging and circulatory biomarkers, specifically carotid arteries and aortic FDG uptake as well as hs-CRP and IL-6 among others. Patients with T2DM or pre-diabetes who have recently experienced a CV event (within 30-120 days after an ACS (ie, ST-elevation MI (STEMI) or non-STEMI)) or TIA/stroke with documented large vessel atherosclerotic disease will be randomised to treatment with either colchicine 0.6 mg oral daily or placebo. Participants will undergo baseline clinical evaluation including EQ5D assessment, blood work for inflammatory markers and FDG PET/CT scan of the ascending aorta and left and right carotid arteries. Patients will undergo treatment for 6 months and have repeat clinical evaluation including EQ5D assessment, blood work for inflammatory markers and FDG PET/CT scan at the conclusion of the study. The primary outcome will be the change in the maximum target to background ratio (TBRmax) in the ascending aorta (or carotid arteries) from baseline to follow-up on FDG PET/CT imaging. DISCUSSION: Colchicine is an exciting potential new therapy for CV risk reduction. However, its use is associated with side effects and greater understanding of its underlying mechanism of action is needed. Importantly, the current study will determine whether its anti-inflammatory action is an indirect systemic effect, or a more local plaque action that decreases inflammation. The results will also help identify patients who will benefit most from such therapy. TRIAL REGISTRATION NUMBER: NCT04181996.
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Arteritis , Aterosclerosis , Diabetes Mellitus Tipo 2 , Ataque Isquémico Transitorio , Estado Prediabético , Accidente Cerebrovascular , Humanos , Fluorodesoxiglucosa F18 , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Radiofármacos , Proteína C-Reactiva , Estudios Prospectivos , Interleucina-6 , Tomografía Computarizada por Tomografía de Emisión de Positrones , Canadá , Aterosclerosis/tratamiento farmacológico , Tomografía Computarizada por Rayos X , Inflamación/tratamiento farmacológico , Biomarcadores , Antiinflamatorios/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Multicéntricos como AsuntoRESUMEN
Background: Donor safety is paramount in living organ donation. Left liver resections are considered safer than right lobe hepatectomies. However, unexpected intraoperative adverse events (iAEs), defined as any deviation from the ideal intraoperative course, can also occur during left liver resections and may be life threatening or lead to postoperative complication or permanent harm to the donor and recipient. Methods: Records of 438 liver living donors (LDs) who underwent 393 left lateral sectionectomies (LLSs) and 45 left hepatectomies (LHs) between July 1993 and December 2018 in a pediatric living-donor liver transplantation center were reviewed for the appearance of iAEs that could have influenced the donor morbidity and mortality and that could have contributed to the improvement of the LD surgical protocol. Results: Clinical characteristics of LLS and LH groups were comparable. Nine iAEs were identified, an incidence of 2%, all of them occurring in the LLS group. Seven of them were related to a surgical maneuver (5 associated with vascular management and 2 with the biliary tree approach). One iAE was associated with an incomplete donor workup and the last with drug administration. Each iAE resulted in subsequent changes in the surgical protocol. Donor outcome was at risk by 5 iAEs classed as type a, recipient outcome by 2 iAEs (type b) and both by 2 iAEs (type c). Postoperative complications occurred in 87 LDs (19.9%), with no differences between the LLS and LH groups (P = 0.227). No Clavien-Dindo class IVa or b complications or donor mortality (Clavien-Dindo class V) were observed. Conclusions: iAEs debriefings induced changes in our LD protocol and may have contributed to reduced morbidity and zero mortality. iAEs analysis can be used as a quality and safety improvement tool in the context of LD procedures, which may include right liver donation, laparoscopic, and robotic living liver graft procurement.
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After 25 years of intersectoral practice to increase health promotion resources, there is little scientific literature linking analysis of processes to observation of effects. Applying Actor-Network Theory, this article examines how the effects of intersectoral action are produced and can be attributed to its processes. A prospective multiple case study (2013-2016) was conducted on Neighbourhood Committees (NCs) in Montreal (Canada). Three NCs were studied using four kinds of data: direct observation notes of meetings and events, documents, logbooks and interviews. Systemic modelling of local intersectoral action was used for data collection and analysis. The results show that the transformations in living environments were produced by sequences of a limited number of 'transitory outcomes' that mark the progression of intersectoral action up to its effects. The list of transitory outcomes identified make up three functions in the production of change: (i) network setup and governance; (ii) self-representing and influencing others; (iii) aligning necessary actors and resources. The production of effects follows a systemic model wherein unique configurations of transitory outcomes, adapted to the different contexts where interactions are occurring, represent the change processes that lead to the effects.
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Redes Comunitarias , Promoción de la Salud , Gobierno Local , Características de la Residencia , Canadá , Atención a la Salud , Humanos , Estudios de Casos Organizacionales , Estudios Prospectivos , Teoría SocialRESUMEN
Behçet's disease is an inflammatory disease, the origin of which still remains unclear, and it has multiple manifestations, one of them being thrombosis. In this report, we describe the case of a 24-year-old Moroccan patient who presented with headache persisting for more than 2 weeks, which was found to be caused by cerebral venous sinus thrombosis. His medical history of recurrent oral and genital ulcerations, epididymitis and one episode of pericarditis led to the diagnosis of Behçet's disease. We could observe an almost complete relief of symptoms with colchicine therapy, and anticoagulation with warfarin was started for secondary prevention of thrombosis.
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A 67-year-old man known with systemic sarcoidosis was admitted to the department of internal medicine because of cough and chest pain for several weeks. Thoracic tomodensitometry demonstrated multiple pulmonary nodules. Biopsies revealed features compatible with abscesses. Cultures and serologic tests were negative and the patient was successfully treated with prednisone. Three years later, a thoraco-abdominal tomodensitometry showed a relapse in the lung and also the apparition of similar lesions in the liver. Blood test revealed elevated CRP level at 40 mg/L and mild cholestasis. Biopsies of the liver excluded neoplastic or infectious diseases and showed inflammatory granulation tissue with abscess formation. A diagnosis of sarcoidosis-associated aseptic abscesses syndrome was then made, which was successfully treated with corticosteroids.
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Absceso Hepático/diagnóstico , Enfermedades Pulmonares/diagnóstico , Sarcoidosis/diagnóstico , Anciano , Humanos , Absceso Hepático/etiología , Enfermedades Pulmonares/etiología , Masculino , Sarcoidosis/etiologíaRESUMEN
A 75-year-old man was admitted to the Department of internal medicine because of a 2-month history of neurological deterioration. During the previous year, he complained of recurrent sinusitis, asthma, arthralgias, myalgias and asthenia. Later on, an oculomotor palsy, weakness and disturbance of the sensibility of the right upper limb appeared. Blood sample showed 6510 eosinophils per microlitre. The cerebral magnetic resonance demonstrated bilateral frontal and left parietal subcortical lesions from which the most voluminous presented large haemorrhagic areas. A cerebral biopsy showed small vessel's vasculitis, fibrinoid necrosis and extravascular eosinophilic encroachment. A diagnosis of oculomotor palsy secondary to eosinophilic granulomatosis with polyangeitis was then made, which was successfully treated with corticosteroids and cyclophosphamide.
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A 25-year-old Somalian man was referred to the department of internal medicine because of nausea, vomiting and jaundice of recent onset. On physical examination, he was frankly icteric without clinical signs of chronic liver disease. Laboratory data showed evidence of acute hepatitis. Viral serologic tests for hepatitis A, B, C and E were negative. Antinuclear antibodies (ANA) were positive (titre 1 : 1280; speckled pattern, NV < 1 : 40) as well anti-actin antibodies (titre 75âUA, NV < 20). A liver biopsy was performed and showed a feature compatible with toxic hepatitis. On further questioning, the patient admitted to daily chew Khat when he was living in Somalia. We concluded to Khat-induced toxic hepatitis together with high-titre anti-nuclear antibody mimicking serologic patterns of auto-immune hepatitis.
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Catha/efectos adversos , Hepatitis , Preparaciones de Plantas/efectos adversos , Adulto , Anticuerpos Antinucleares , Hepatitis/diagnóstico , Hepatitis/etiología , Hepatitis/fisiopatología , Humanos , Hígado/efectos de los fármacos , Hígado/patología , Masculino , MasticaciónRESUMEN
OBJECTIVES: To evaluate the outcome of pediatric living donor liver transplantation (LDLT) regarding portal vein (PV) reconstruction, ABO compatibility, and impact of maternal donation on graft acceptance. BACKGROUND: LDLT and ABO-mismatched transplantation constitute feasible options to alleviate organ shortage in children. Vascular complications of portal hypoplasia in biliary atresia (BA) and acute rejection (AR) are still major concerns in this field. METHODS: Data from 250 pediatric LDLT recipients, performed at Cliniques Universitaires Saint-Luc between July 1993 and June 2012, were collected retrospectively. Results were analyzed according to ABO matching and PV complications. Uni- and multivariate analyses were performed to study the impact of immunosuppression, sex matching, and maternal donation on AR rate. RESULTS: Overall, the 10-year patient survival rate was 93.2%. Neither patient or graft loss nor vascular rejection, nor hemolysis, was encountered in the ABO nonidentical patients (nâ=â58), provided pretransplant levels of relevant isoagglutinins were below 1/16. In BA recipients, the rate of PV complications was lower after portoplasty (4.6%) than after truncal PV anastomosis (9.8%) and to jump graft interposition (26.9%; Pâ=â0.027). In parental donation, maternal grafts were associated with higher 1-year AR-free survival (55.2%) than paternal grafts (39.8%; Pâ=â0.041), but only in BA patients. CONCLUSIONS: LDLT, including ABO-mismatched transplantation, constitutes a safe and efficient therapy for liver failure in children. In BA patients with PV hypoplasia, portoplasty seems to constitute the best technique for PV reconstruction. Maternal donation might be a protective factor for AR.
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Trasplante de Hígado/métodos , Donadores Vivos , Sistema del Grupo Sanguíneo ABO/inmunología , Adolescente , Adulto , Incompatibilidad de Grupos Sanguíneos , Niño , Preescolar , Femenino , Rechazo de Injerto/inmunología , Rechazo de Injerto/prevención & control , Humanos , Lactante , Trasplante de Hígado/mortalidad , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Vena Porta/cirugía , Estudios Retrospectivos , Adulto JovenAsunto(s)
Arteritis/etiología , Granulomatosis con Poliangitis/complicaciones , Hipertensión Pulmonar/etiología , Arteria Pulmonar , Disnea/etiología , Ecocardiografía , Ecocardiografía Transesofágica , Edema/etiología , Femenino , Humanos , Hallazgos Incidentales , Persona de Mediana Edad , Estenosis de la Válvula Pulmonar/etiologíaRESUMEN
GATA4-6 transcription factors regulate numerous aspects of development and homeostasis in multiple tissues of mesodermal and endodermal origin. In the heart, the best studied of these factors, GATA4, has multiple distinct roles in cardiac specification, differentiation, morphogenesis, hypertrophy and survival. To improve understanding of how GATA4 achieves its numerous roles in the heart, here we have focused on the carboxy-terminal domain and the residues required for interaction with cofactors FOG2 and Tbx5. We present evidence that the carboxy terminal region composed of amino acids 362-400 is essential for mediating cardiogenesis in Xenopus pluripotent explants and embryos. In contrast, the same region is not required for endoderm-inducing activity of GATA4. Further evidence is presented that the carboxy terminal cardiogenic region of GATA4 does not operate as a generic transcriptional activator. Potential mechanism of action of the carboxy terminal end of GATA4 is provided by the results showing physical and functional interaction with CDK4, including the enhancement of cardiogenic activity of GATA4 by CDK4. These results establish CDK4 as a GATA4 partner in cardiogenesis. The interactions of GATA4 with its other well described cofactors Tbx5 and FOG2 are known to be involved in heart morphogenesis, but their requirement for cardiac differentiation is unknown. We report that the mutations that disrupt interactions of GATA4 with Tbx5 and FOG2, G295S and V217G, respectively, do not impair cardiogenic activity of GATA4. These findings add support to the view that distinct roles of GATA4 in the heart are mediated by different determinants of the protein. Finally, we show that the rat GATA4 likely induces cardiogenesis cell autonomously or directly as it does not require activity of endodermal transcription factor Sox17, a GATA4 target gene that induces cardiogenesis non-cell autonomously.
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Quinasa 4 Dependiente de la Ciclina/metabolismo , Factor de Transcripción GATA4/metabolismo , Regulación del Desarrollo de la Expresión Génica , Corazón/embriología , Miocardio/metabolismo , Células 3T3 , Animales , Diferenciación Celular/genética , Quinasa 4 Dependiente de la Ciclina/genética , Factor de Transcripción GATA4/genética , Ratones , Miocitos Cardíacos/metabolismo , Organogénesis/genética , Ratas , Xenopus laevisRESUMEN
In humans, septal defects are among the most prevalent congenital heart diseases, but their cellular and molecular origins are not fully understood. We report that transcription factor Tbx5 is present in a subpopulation of endocardial cells and that its deletion therein results in fully penetrant, dose-dependent atrial septal defects in mice. Increased apoptosis of endocardial cells lacking Tbx5, as well as neighboring TBX5-positive myocardial cells of the atrial septum through activation of endocardial NOS (Nos3), is the underlying mechanism of disease. Compound Tbx5 and Nos3 haploinsufficiency in mice worsens the cardiac phenotype. The data identify a pathway for endocardial cell survival and unravel a cell-autonomous role for Tbx5 therein. The finding that Nos3, a gene regulated by many congenital heart disease risk factors including stress and diabetes, interacts genetically with Tbx5 provides a molecular framework to understand gene-environment interaction in the setting of human birth defects.
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Tabique Interatrial/citología , Endocardio/citología , Factor de Transcripción GATA4/fisiología , Cardiopatías/congénito , Óxido Nítrico Sintasa de Tipo III/fisiología , Proteínas de Dominio T Box/fisiología , Animales , Tabique Interatrial/patología , Supervivencia Celular , Endocardio/patología , Haploinsuficiencia , Cardiopatías Congénitas/etiología , Cardiopatías Congénitas/genética , Ratones , Fenotipo , Proteínas de Dominio T Box/análisisAsunto(s)
Educación Continua en Enfermería/organización & administración , Masaje/educación , Personal de Enfermería , Tacto , Actitud del Personal de Salud , Francia , Cuidados Paliativos al Final de la Vida/métodos , Cuidados Paliativos al Final de la Vida/psicología , Hospitales para Enfermos Terminales , Humanos , Masaje/enfermería , Masaje/psicología , Investigación en Educación de Enfermería , Investigación Metodológica en Enfermería , Personal de Enfermería/educación , Personal de Enfermería/psicología , Salud Laboral , Desarrollo de Programa , Evaluación de Programas y Proyectos de Salud , Encuestas y CuestionariosRESUMEN
Mutations in the T-box transcription factor Tbx5 cause Holt-Oram syndrome, an autosomal dominant disease characterized by a wide spectrum of cardiac and upper limb defects with variable expressivity. Tbx5 haploinsufficiency has been suggested to be the underlying mechanism, and experimental models are consistent with a dosage-sensitive requirement for Tbx5 in heart development. Here, we report that Tbx5 levels are regulated through alternative splicing that generates, in addition to the known 518-amino-acid protein, a C-terminal truncated isoform. This shorter isoform retains the capacity to bind DNA, but its interaction with Tbx5 collaborators such as GATA-4 is altered. In vivo, the two spliced isoforms are oppositely regulated in a temporal and growth factor-dependent manner and are present in distinct DNA-binding complexes. The expression of the long isoform correlates with growth stimulation, and its reexpression in postnatal transgenic mouse hearts promotes hypertrophy. Conversely, the upregulation of the short but not the long isoform in C2C12 myoblasts leads to growth arrest and cell death. The results provide novel insight into posttranscriptional Tbx5 regulation and point to an important role not only in cell differentiation but also in cell proliferation and organ growth. The data may help analyze genotype-phenotype relations in patients with Holt-Oram syndrome.
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Regulación de la Expresión Génica , Proteínas de Dominio T Box/química , Empalme Alternativo , Animales , Diferenciación Celular , Proliferación Celular , Factor de Transcripción GATA4/química , Genotipo , Ratones , Ratones Transgénicos , Modelos Biológicos , Células 3T3 NIH , Fenotipo , Isoformas de Proteínas , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Sterol regulatory element-binding proteins (SREBPs) are transcription factors governing transcription of genes related to cholesterol and fatty acid metabolism. To become active, SREBPs must undergo a proteolytic cleavage to allow an active NH(2)-terminal segment to translocate into the nucleus. SKI-1/S1P is the first protease in the proteolytic activation cascade of SREBPs. SREBP inhibition may be useful, for example, in the treatment of liver steatosis caused by homocysteine-induced lipid synthesis. Accordingly, we overexpressed inhibitory prodomains (proSKI) of SKI-1/S1P in HepG2 cells to block SREBP activation to evaluate the potential of SKI-1/S1P in controlling cellular cholesterol synthesis. SKI-1/S1P inhibition resulted in reduced cholesterol synthesis and mRNA levels of the rate-limiting enzymes, HMG-CoA reductase and squalene epoxidase, in the cholesterol synthetic pathway. The inhibitory effect was maintained in the presence of homocysteine-induced endoplasmic reticulum stress. A gene set enrichment analysis was performed to elucidate other metabolic effects caused by SKI-1/S1P inhibition. SKI-1/S1P inhibition was observed to affect a number of other metabolic pathways, including glycolysis and citric acid cycle. These results demonstrate that inhibition of SREBPs decreases cholesterol synthesis in HepG2 cells both in the absence and presence of homocysteine. SKI-1/S1P inhibition may cause widespread changes in other key metabolic pathways.
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Colesterol/metabolismo , Homocisteína/metabolismo , Proproteína Convertasas/antagonistas & inhibidores , Proteínas de Unión a los Elementos Reguladores de Esteroles/antagonistas & inhibidores , Línea Celular , Glucólisis , Humanos , Redes y Vías Metabólicas , Análisis de Secuencia por Matrices de Oligonucleótidos , Proproteína Convertasas/farmacología , ARN Mensajero/metabolismo , Serina EndopeptidasasRESUMEN
In humans, congenital heart defects occur in 1-2% of live birth, but the molecular mechanisms and causative genes remain unidentified in the majority of cases. We have uncovered a novel transcription pathway important for heart morphogenesis. We report that KLF13, a member of the Krüppel-like family of zinc-finger proteins, is expressed predominantly in the heart, binds evolutionarily conserved regulatory elements on cardiac promoters and activates cardiac transcription. KLF13 is conserved across species and knockdown of KLF13 in Xenopus embryos leads to atrial septal defects and hypotrabeculation similar to those observed in humans or mice with hypomorphic GATA-4 alleles. Physical and functional interaction with GATA-4, a dosage-sensitive cardiac regulator, provides a mechanistic explanation for KLF13 action in the heart. The data demonstrate that KLF13 is an important component of the transcription network required for heart development and suggest that KLF13 is a GATA-4 modifier; by analogy to other GATA-4 collaborators, mutations in KLF13 may be causative for congenital human heart disease.
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Factor de Transcripción GATA4/metabolismo , Regulación del Desarrollo de la Expresión Génica , Corazón/embriología , Factores de Transcripción de Tipo Kruppel/metabolismo , Proteínas de Xenopus/metabolismo , Alelos , Animales , Factor de Transcripción GATA4/genética , Dosificación de Gen , Regulación del Desarrollo de la Expresión Génica/genética , Defectos del Tabique Interatrial/embriología , Defectos del Tabique Interatrial/genética , Defectos del Tabique Interatrial/patología , Humanos , Factores de Transcripción de Tipo Kruppel/genética , Ratones , Mutación , Miocardio/patología , Células 3T3 NIH , Transcripción Genética/genética , Proteínas de Xenopus/genética , Xenopus laevisRESUMEN
We report on a 30-year-old man, with type 1 diabetes mellitus, who developed generalized allergy to insulin consisting of several bouts of tremor, tachycardia, breathlessness and syncope. Strong positive reactions to protamine and metacresol were demonstrated by skin-prick testing. Symptoms persisted despite the use of antihistamine therapy, Actrapid HM Paraben and Monotard (insulin without protamine and metacresol) and immunosuppression (tacrolimus). He underwent a cadaver pancreas transplantation with portal-enteric drainage in June 2003. Following the antithymocyte globulin induction, immunosuppression consisted in tacrolimus and sirolimus without steroids. The patient subsequently reported a complete resolution of his symptoms and excellent glycaemic control. Thirteen months after transplantation, the patient developed oral ulcerations and severe leucopoenia initially attributed to sirolimus, which was subsequently stopped. A hyperglycaemic episode following corticosteroid therapy for acute rejection therapy required the reintroduction of insulin. Allergic manifestations reappeared promptly. Currently, 2 years after transplantation, the patient is euglycaemic without insulin (glycated haemoglobin 5.8%) and he is free of allergic reactions.
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Hipersensibilidad Inmediata/terapia , Hipersensibilidad/inmunología , Hipersensibilidad/terapia , Insulina/inmunología , Trasplante de Páncreas/métodos , Adulto , Diabetes Mellitus Tipo 1/inmunología , Diabetes Mellitus Tipo 1/terapia , Homeostasis , Humanos , Inmunosupresores/toxicidad , Insulina/química , Resistencia a la Insulina , Masculino , Protaminas/toxicidad , Sirolimus/toxicidad , Tacrolimus/toxicidadRESUMEN
Angiotensin II (AII), a potent vasoactive hormone, acts on numerous organs via G-protein-coupled receptors and elicits cell-specific responses. At the level of the heart, AII stimulation alters gene transcription and leads to cardiomyocyte hypertrophy. Numerous intracellular signaling pathways are activated in this process; however, which of these directly link receptor activation to transcriptional regulation remains undefined. We used the atrial natriuretic factor (ANF) gene (NPPA) as a marker to elucidate the signaling cascades involved in AII transcriptional responses. We show that ANF transcription is activated directly by the AII type 1 receptor and precedes the development of myocyte hypertrophy. This response maps to STAT and GATA binding sites, and the two elements transcriptionally cooperate to mediate signaling through the JAK-STAT and protein kinase C (PKC)-GATA-4 pathways. PKC phosphorylation enhances GATA-4 DNA binding activity, and STAT-1 functionally and physically interacts with GATA-4 to synergistically activate AII and other growth factor-inducible promoters. Moreover, GATA factors are able to recruit STAT proteins to target promoters via GATA binding sites, which are sufficient to support synergy. Thus, STAT proteins can act as growth factor-inducible coactivators of tissue-specific transcription factors. Interactions between STAT and GATA proteins may provide a general paradigm for understanding cell specificity of cytokine and growth factor signaling.
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Factor de Transcripción GATA4/fisiología , Regulación de la Expresión Génica , Proteína Quinasa C/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Factores de Transcripción STAT/metabolismo , Adenoviridae/genética , Angiotensina II/metabolismo , Animales , Factor Natriurético Atrial/metabolismo , Sitios de Unión , Northern Blotting , Línea Celular , Núcleo Celular/metabolismo , Proliferación Celular , Inmunoprecipitación de Cromatina , Citocinas/metabolismo , ADN/metabolismo , Inhibidores Enzimáticos/farmacología , Humanos , Inmunoprecipitación , Ratones , Modelos Genéticos , Miocitos Cardíacos/metabolismo , Células 3T3 NIH , Fosforilación , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , Ratas , Transducción de Señal , Transcripción Genética , Activación Transcripcional , Fosfolipasas de Tipo C/metabolismoRESUMEN
In recent years, significant progress has been made in understanding cardiomyocyte differentiation. However, little is known about the regulation of myocyte survival despite the fact that myocyte apoptosis is a leading cause of heart failure. Here we report that transcription factor GATA-4 is a survival factor for differentiated, postnatal cardiomyocytes and an upstream activator of the antiapoptotic gene Bcl-X. An early event in the cardiotoxic effect of the antitumor drug doxorubicin is GATA-4 depletion, which in turn causes cardiomyocyte apoptosis. Mouse heterozygotes for a null Gata4 allele have enhanced susceptibility to doxorubicin cardiotoxicity. Genetic or pharmacologic enhancement of GATA-4 prevents cardiomyocyte apoptosis and drug-induced cardiotoxicity. The results indicate that GATA-4 is an antiapoptotic factor required for the adaptive stress response of the adult heart. Modulation of survival/apoptosis genes by tissue-specific transcription factors may be a general paradigm that can be exploited effectively for cell-specific regulation of apoptosis in disease states.
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Antibióticos Antineoplásicos/toxicidad , Supervivencia Celular/fisiología , Proteínas de Unión al ADN/metabolismo , Doxorrubicina/toxicidad , Miocitos Cardíacos/fisiología , Factores de Transcripción/metabolismo , Apoptosis/fisiología , Factor de Transcripción GATA4 , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteína bcl-XRESUMEN
c-Fos is a multifunctional transcription factor that is involved in cellular proliferation, differentiation and apoptosis. c-Fos is rapidly induced by a variety of hormones, growth factors and other extracellular stimuli, resulting in cell-specific responses. One potential mechanism underlying the cell-specific effects of c-Fos may be its ability to regulate gene expression through interaction with tissue-restricted transcription factors. We report here that c-Fos interacts with the cell-specific GATA proteins to potentiate their ability to transactivate target promoters, via GATA-binding sites. c-Fos is recruited to GATA proteins through direct interaction with their N-terminal activation domain. Neither the leucine zipper nor the DNA-binding domain of c-Fos is required for physical interaction with GATA proteins. Instead, a C-terminal domain located between amino acids 235 and 296, which is conserved in FosB but not in the nontransforming Fos family members, FosB/SF or Fra-1, is essential for c-Fos-GATA interaction. These data suggest that c-Fos may act as an inducible cofactor for cell-specific transcription factors and unravel a novel mechanism for transcriptional regulation by c-Fos, independent of the well-studied AP-1 pathway. The results also raise the possibility that dysregulated interaction with cell-specific transcription factors may be an important component in cellular transformation by nuclear oncogenes.