RESUMO
BACKGROUND: Hypertensive ventricular remodeling is a common cause of heart failure. However, the molecular mechanisms regulating ventricular remodeling remain poorly understood. METHODS: We used a discovery-driven/nonbiased approach to identify increased activating transcription factor 3 (ATF3) expression in hypertensive heart. We used loss/gain of function approaches to understand the role of ATF3 in heart failure. We also examined the mechanisms through transcriptome, chromatin immunoprecipitation sequencing analysis, and in vivo and in vitro experiments. RESULTS: ATF3 expression increased in murine hypertensive heart and human hypertrophic heart. Cardiac fibroblast cells are the primary cell type expressing high ATF3 levels in response to hypertensive stimuli. ATF3 knockout (ATF3KO) markedly exaggerated hypertensive ventricular remodeling, a state rescued by lentivirus-mediated/miRNA-aided cardiac fibroblast-selective ATF3 overexpression. Conversely, conditional cardiac fibroblast cell-specific ATF3 transgenic overexpression significantly ameliorated ventricular remodeling and heart failure. We identified Map2K3 as a novel ATF3 target. ATF3 binds with the Map2K3 promoter, recruiting HDAC1, resulting in Map2K3 gene-associated histone deacetylation, thereby inhibiting Map2K3 expression. Genetic Map2K3 knockdown rescued the profibrotic/hypertrophic phenotype in ATF3KO cells. Last, we demonstrated that p38 is the downstream molecule of Map2K3 mediating the profibrotic/hypertrophic effects in ATF3KO animals. Inhibition of p38 signaling reduced transforming growth factor-ß signaling-related profibrotic and hypertrophic gene expression, and blocked exaggerated cardiac remodeling in ATF3KO cells. CONCLUSIONS: Our study provides the first evidence that ATF3 upregulation in cardiac fibroblasts in response to hypertensive stimuli protects the heart by suppressing Map2K3 expression and subsequent p38-transforming growth factor-ß signaling. These results suggest that positive modulation of cardiac fibroblast ATF3 may represent a novel therapeutic approach against hypertensive cardiac remodeling.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Fibroblastos/enzimologia , Insuficiência Cardíaca/prevenção & controle , Hipertrofia Ventricular Esquerda/prevenção & controle , MAP Quinase Quinase 3/metabolismo , Miocárdio/enzimologia , Função Ventricular Esquerda , Remodelação Ventricular , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Acetilação , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Angiotensina II , Animais , Sítios de Ligação , Células Cultivadas , Modelos Animais de Doenças , Fibroblastos/patologia , Fibrose , Predisposição Genética para Doença , Insuficiência Cardíaca/enzimologia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/fisiopatologia , Histona Desacetilase 1/metabolismo , Histonas/metabolismo , Humanos , Hipertensão/induzido quimicamente , Hipertrofia Ventricular Esquerda/enzimologia , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/fisiopatologia , MAP Quinase Quinase 3/genética , Masculino , Camundongos Knockout , Miocárdio/patologia , Fenótipo , Regiões Promotoras Genéticas , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais , Fatores de Tempo , Fator de Crescimento Transformador beta/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
Excessive inflammatory responses are critical in the pathogenesis of acute lung injury (ALI). Activating transcription factor 3 (ATF3) is a stress-induced transcriptional regulator that is a negative regulator of inflammatory responses. Therefore, we investigated the role and signaling pathways of ATF3 in lipopolysaccharide (LPS)-induced ALI in mice. The mouse macrophage RAW264.7 cells were cultured on HTS 24-Transwell filter plates in presence of ATF3 siRNA before exposure to LPS. ATF3 knock-out (KO) and wild type (WT) mice were challenged by intra-peritoneal injection of LPS (15 mg/kg). Gene analysis was used to analyze differential gene expression between ATF3 KO and WT mice. LPS increased the expression of ATF3 in RAW264.7 cells and in lung tissues of mice, The concentration of TNFα and IL-6 was significantly increased in ATF3 siRNA-treated RAW264.7 cells compared to control cells after LPS stimulation. The concentration of TNFα, IL-6 and IL-1ß in serum and lung tissue of ATF3 KO mice was significantly increased compared to ATF3 WT mice. In addition, the lung wet/dry weight and BALF protein were significantly increased in ATF3 KO mice after LPS injection at 6, 24, and 48 hr. The survival of ATF3 KO mice significantly decreased. Differential gene analysis showed that TL1A was highly expressed in LPS-induced lung tissues of ATF3 KO mice.Moreover, ATF3 down-regulated the expression of TL1A in RAW264.7 cells and in lung tissues. These findings suggest that ATF3 protects against LPS-induced ALI via inhibiting TL1A expression.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Lesão Pulmonar Aguda/prevenção & controle , Lipopolissacarídeos , Pulmão/metabolismo , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismo , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/genética , Lesão Pulmonar Aguda/metabolismo , Animais , Líquido da Lavagem Broncoalveolar/química , Permeabilidade Capilar , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Regulação para Baixo , Perfilação da Expressão Gênica/métodos , Predisposição Genética para Doença , Mediadores da Inflamação/metabolismo , Pulmão/irrigação sanguínea , Pulmão/patologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Células RAW 264.7 , Interferência de RNA , Transdução de Sinais , Fatores de Tempo , Transfecção , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genéticaRESUMO
Numerous fibrotic and inflammatory changes occur in the failing heart. Recent evidence indicates that certain transcription factors, such as activating transcription factor 3 (ATF3), are activated during heart failure. Because ATF3 may be upregulated in the failing heart and affect inflammation, we focused on the potential role of ATF3 on postinfarct heart failure. We subjected anesthetized, wild-type mice to nonreperfused myocardial infarction and observed a significant induction in ATF3 expression and nuclear translocation. To test whether the induction of ATF3 affected the severity of heart failure, we subjected wild-type and ATF3-null mice to nonreperfused infarct-induced heart failure. There were no differences in cardiac function between the two genotypes, except at the 2-wk time point; however, ATF3-null mice survived the heart failure protocol at a significantly higher rate than the wild-type mice. Similar to the slight favorable improvements in chamber dimensions at 2 wk, we also observed greater cardiomyocyte hypertrophy and more fibrosis in the noninfarcted regions of the ATF3-null hearts compared with the wild-type. Nevertheless, there were no significant group differences at 4 wk. Furthermore, we found no significant differences in markers of inflammation between the wild-type and ATF3-null hearts. Our data suggest that ATF3 suppresses fibrosis early but not late during infarct-induced heart failure. Although ATF3 deficiency was associated with more fibrosis, this did not occur at the expense of survival, which was higher in the ATF3-null mice. Overall, ATF3 may serve a largely maladaptive role during heart failure.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Insuficiência Cardíaca/etiologia , Infarto do Miocárdio/complicações , Miocárdio/metabolismo , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Cardiomegalia/etiologia , Cardiomegalia/metabolismo , Cardiomegalia/patologia , Modelos Animais de Doenças , Fibrose , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Mediadores da Inflamação/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Miocárdio/patologia , Fatores de Tempo , Remodelação VentricularRESUMO
Transcriptional repressor activating transcription factor 3 (ATF3) is induced by various stress stimuli, including inflammation-induced renal injury. In addition, ATF3 also down-regulates adhesion molecules like intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), and monocyte chemotactic protein-1 (MCP-1). However, the relation between up-regulated ATF3 after renal ischemia/reperfusion (I/R) injury and MCP-1 is not completely understood. In this study, we demonstrated that, in renal I/R induced inflammation, induction of adhesion molecules (interleukin-6, P-selectin, E-selectin, ICAM, VCAM, and MCP-1) was higher in ATF3-knockout mice than in wild-type animals. Molecular and biochemical analyses revealed that ATF3 binds to the ATF/CRE sites in the MCP-1 promoter and inhibits the secretion of MCP-1 from renal epithelial cells after I/R injury. Urinary exosome containing ATF3 RNA was 60-fold higher in patients with acute kidney injury than in normal controls, but no difference in total urinary ATF3 RNA levels was found. In addition, in vitro study showed that exosome containing ATF3 RNA derived from epithelial cells also inhibits MCP-1 expression in the epithelial cells and macrophage migration. Furthermore, direct administration of the epithelium-derived exosomal ATF3 RNA attenuates I/R induced kidney injury. Together, our studies reveal a novel regulatory mechanism of MCP-1 expression mediated by the exosomal ATF3 RNA under renal I/R insult and suggest a potential targeted therapy for I/R induced acute kidney injury.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Injúria Renal Aguda/metabolismo , Quimiocina CCL2/metabolismo , Exossomos/metabolismo , Mediadores da Inflamação/metabolismo , Rim/metabolismo , Traumatismo por Reperfusão/metabolismo , Transcrição Gênica , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Fator 3 Ativador da Transcrição/urina , Injúria Renal Aguda/genética , Injúria Renal Aguda/imunologia , Injúria Renal Aguda/patologia , Injúria Renal Aguda/urina , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Sítios de Ligação , Linhagem Celular , Quimiocina CCL2/genética , Modelos Animais de Doenças , Regulação para Baixo , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Exossomos/imunologia , Feminino , Humanos , Rim/irrigação sanguínea , Rim/imunologia , Rim/patologia , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Interferência de RNA , RNA Mensageiro/metabolismo , Ratos , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/imunologia , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/urina , Transdução de Sinais , Fatores de Tempo , TransfecçãoRESUMO
OBJECTIVE: Elevation of triglyceride-rich lipoproteins (TGRLs) contributes to the risk of atherosclerotic cardiovascular disease. Our work has shown that TGRL lipolysis products in high physiological to pathophysiological concentrations cause endothelial cell injury; however, the mechanisms remain to be delineated. APPROACH AND RESULTS: We analyzed the transcriptional signaling networks in arterial endothelial cells exposed to TGRL lipolysis products. When human aortic endothelial cells in culture were exposed to TGRL lipolysis products, activating transcription factor 3 (ATF3) was identified as a principal response gene. Induction of ATF3 mRNA and protein was confirmed by quantitative reverse-transcription polymerase chain reaction and Western blot respectively. Immunofluorescence analysis showed that ATF3 accumulated in the nuclei of cells treated with lipolysis products. Nuclear expression of phosphorylated c-Jun N-terminal kinase (JNK), previously shown to be an initiator of the ATF3 signaling cascade, also was demonstrated. Small interfering RNA (siRNA)-mediated inhibition of ATF3 blocked lipolysis products-induced transcription of E-selectin and interleukin-8, but not interleukin-6 or nuclear factor-κB. c-Jun, a downstream protein in the JNK pathway, was phosphorylated, whereas expression of nuclear factor-κB-dependent JunB was downregulated. Additionally, JNK siRNA suppressed ATF3 and p-c-Jun protein expression, suggesting that JNK is upstream of the ATF3 signaling pathway. In vivo studies demonstrated that infusion of TGRL lipolysis products into wild-type mice induced nuclear ATF3 accumulation in carotid artery endothelium. ATF3(-/-) mice were resistant to vascular apoptosis precipitated by treatment with TGRL lipolysis products. Also peripheral blood monocytes isolated from postprandial humans had increased ATF3 expression as compared with fasting monocytes. CONCLUSIONS: This study demonstrates that TGRL lipolysis products activate ATF3-JNK transcription factor networks and induce endothelial cells inflammatory response.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Apoptose , Células Endoteliais/metabolismo , Inflamação/metabolismo , Lipoproteínas/metabolismo , Triglicerídeos/metabolismo , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Western Blotting , Células Cultivadas , Selectina E/metabolismo , Células Endoteliais/imunologia , Células Endoteliais/patologia , Ativação Enzimática , Imunofluorescência , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Humanos , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Interleucina-8/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Leucócitos Mononucleares/metabolismo , Lipólise , Lipase Lipoproteica/metabolismo , Lipoproteínas/sangue , Lipoproteínas/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação , Interferência de RNA , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção , Triglicerídeos/sangueRESUMO
Endothelin-1 promotes cardiomyocyte hypertrophy by inducing changes in gene expression. Immediate early genes including Atf3 (activating transcription factor 3), Egr1 (early growth response 1) and Ptgs2 (prostaglandin-endoperoxide synthase 2) are rapidly and transiently up-regulated by endothelin-1 in cardiomyocytes. Atf3 regulates the expression of downstream genes and is implicated in negative feedback regulation of other immediate early genes. To identify Atf3-regulated genes, we knocked down Atf3 expression in cardiomyocytes exposed to endothelin-1 and used microarrays to interrogate the transcriptomic effects. The expression of 23 mRNAs (including Egr1 and Ptgs2) was enhanced and the expression of 25 mRNAs was inhibited by Atf3 knockdown. Using quantitative PCR, we determined that knockdown of Atf3 had little effect on up-regulation of Egr1 mRNA over 30 min, but abolished the subsequent decline, causing sustained Egr1 mRNA expression and enhanced protein expression. This resulted from direct binding of Atf3 to the Egr1 promoter. Mathematical modelling established that Atf3 can suffice to suppress Egr1 expression. Given the widespread co-regulation of Atf3 with Egr1, we suggest that the Atf3-Egr1 negative feedback loop is of general significance. Loss of Atf3 caused abnormal cardiomyocyte growth, presumably resulting from the dysregulation of target genes. The results of the present study therefore identify Atf3 as a nexus in cardiomyocyte hypertrophy required to facilitate the full and proper growth response.
Assuntos
Fator 3 Ativador da Transcrição/fisiologia , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Endotelina-1/fisiologia , Retroalimentação Fisiológica/fisiologia , Marcação de Genes , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Transcriptoma/genética , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Animais Recém-Nascidos , Sequência de Bases , Células Cultivadas , Ciclo-Oxigenase 2/biossíntese , Proteína 1 de Resposta de Crescimento Precoce/antagonistas & inibidores , Proteína 1 de Resposta de Crescimento Precoce/biossíntese , Retroalimentação Fisiológica/efeitos dos fármacos , Marcação de Genes/métodos , Hipertrofia Ventricular Esquerda/genética , Hipertrofia Ventricular Esquerda/metabolismo , Hipertrofia Ventricular Esquerda/patologia , Dados de Sequência Molecular , Miócitos Cardíacos/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transcriptoma/efeitos dos fármacos , Regulação para Cima/genéticaRESUMO
The innate immune system is absolutely required for host defence, but, uncontrolled, it leads to inflammatory disease. This control is mediated, in part, by cytokines that are secreted by macrophages. Immune regulation is extraordinarily complex, and can be best investigated with systems approaches (that is, using computational tools to predict regulatory networks arising from global, high-throughput data sets). Here we use cluster analysis of a comprehensive set of transcriptomic data derived from Toll-like receptor (TLR)-activated macrophages to identify a prominent group of genes that appear to be regulated by activating transcription factor 3 (ATF3), a member of the CREB/ATF family of transcription factors. Network analysis predicted that ATF3 is part of a transcriptional complex that also contains members of the nuclear factor (NF)-kappaB family of transcription factors. Promoter analysis of the putative ATF3-regulated gene cluster demonstrated an over-representation of closely apposed ATF3 and NF-kappaB binding sites, which was verified by chromatin immunoprecipitation and hybridization to a DNA microarray. This cluster included important cytokines such as interleukin (IL)-6 and IL-12b. ATF3 and Rel (a component of NF-kappaB) were shown to bind to the regulatory regions of these genes upon macrophage activation. A kinetic model of Il6 and Il12b messenger RNA expression as a function of ATF3 and NF-kappaB promoter binding predicted that ATF3 is a negative regulator of Il6 and Il12b transcription, and this hypothesis was validated using Atf3-null mice. ATF3 seems to inhibit Il6 and Il12b transcription by altering chromatin structure, thereby restricting access to transcription factors. Because ATF3 is itself induced by lipopolysaccharide, it seems to regulate TLR-stimulated inflammatory responses as part of a negative-feedback loop.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Biologia de Sistemas , Receptor 4 Toll-Like/antagonistas & inibidores , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Sequência de Bases , Sítios de Ligação , Análise por Conglomerados , Regulação da Expressão Gênica/efeitos dos fármacos , Cinética , Lipopolissacarídeos/farmacologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Elementos de Resposta/genética , Receptor 4 Toll-Like/metabolismo , Transcrição Gênica/efeitos dos fármacos , Transcrição Gênica/genéticaRESUMO
Activating transcription factor 3 (ATF3) is a negative regulator of proinflammatory cytokine expression in macrophages, and ATF3-deficient mice are more susceptible to endotoxic shock. Here, we demonstrate that ATF3 interacts with a cis-regulatory element of the IFN-gamma gene in natural killer (NK) cells, and that ATF3null NK cells show increased transcription and secretion of IFN-gamma. NK cell-derived IFN-gamma has previously been demonstrated to be protective against murine cytomegalovirus (MCMV) infection, and we show here that ATF3null mice exhibit decreased hepatic viral load and reduced liver histopathology upon challenge with MCMV. Reconstitution of NK-deficient mice with ATF3null NK cells more effectively controlled MCMV infection than mice reconstituted with WT cells, indicating that ATF3 acts within NK cells to regulate antiviral responses.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Infecções por Citomegalovirus/metabolismo , Interferon gama/metabolismo , Células Matadoras Naturais/metabolismo , Muromegalovirus/fisiologia , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Infecções por Citomegalovirus/genética , Infecções por Citomegalovirus/prevenção & controle , Infecções por Citomegalovirus/virologia , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/genéticaRESUMO
Decidualization is a complex process involving cellular proliferation and differentiation of the endometrial stroma and is required to establish and support pregnancy. Dysregulated decidualization has been reported to be a critical cause of recurrent implantation failure (RIF). In this study, we found that Activating transcription factor 3 (ATF3) expression was significantly downregulated in the endometrium of RIF patients. Knockdown of ATF3 in human endometrium stromal cells (hESCs) hampers decidualization, while overexpression could trigger the expression of decidual marker genes, and ameliorate the decidualization of hESCs from RIF patients. Mechanistically, ATF3 promotes decidualization by upregulating FOXO1 via suppressing miR-135b expression. In addition, the endometrium of RIF patients was hyperproliferative, while overexpression of ATF3 inhibited the proliferation of hESCs through CDKN1A. These data demonstrate the critical roles of endometrial ATF3 in regulating decidualization and proliferation, and dysregulation of ATF3 in the endometrium may be a novel cause of RIF and therefore represent a potential therapeutic target for RIF.
Assuntos
Fator 3 Ativador da Transcrição/deficiência , Implantação do Embrião/fisiologia , Endométrio/fisiologia , Fator 3 Ativador da Transcrição/genética , Fator 3 Ativador da Transcrição/metabolismo , Proliferação de Células/fisiologia , Células Cultivadas , Decídua/metabolismo , Endométrio/metabolismo , Feminino , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/metabolismo , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Células Estromais/metabolismo , TransfecçãoRESUMO
Arsenic is a naturally occurring metalloid strongly associated with the incidence of lung cancer. Understanding the mechanisms of arsenic-induced carcinogenesis favors the development of effective interventions to reduce the incidence and mortality of lung cancer. In this study, we investigated the role of activating transcription factor 3 (ATF3) in arsenic-induced transformation of human bronchial epithelial cells. ATF3 was upregulated during chronic exposure to 0.25 µM arsenic, and loss of ATF3 promoted arsenic-induced transformation. Moreover, arsenic-transformed ATF3 knockout (ATF3 KO-AsT) cells exhibited more aggressive characteristics, including acceleration in proliferation, resistance to chemotherapy and increase in migratory capacity. RNA-seq revealed that pathways involved in inflammation, cell cycle, EMT and oncogenesis were affected due to ATF3 deficiency during chronic arsenic exposure. Further experiments confirmed the overproduction of IL-6, IL-8 and TNFα as well as enhanced phosphorylation of AKT and STAT3 in ATF3 KO-AsT cells. Our results demonstrate that ATF3 upregulated by chronic low-dose arsenic exposure represses cell transformation and acquisition of malignant characteristics through inhibiting the production of proinflammatory cytokines and activation of downstream proteins AKT and STAT3, providing a new strategy for the prevention of carcinogen-induced lung cancer.
Assuntos
Fator 3 Ativador da Transcrição/deficiência , Arsênio/toxicidade , Brônquios/metabolismo , Mediadores da Inflamação/metabolismo , Neoplasias Pulmonares/metabolismo , Mucosa Respiratória/metabolismo , Fator 3 Ativador da Transcrição/genética , Animais , Linhagem Celular Transformada , Feminino , Técnicas de Inativação de Genes/métodos , Células HEK293 , Humanos , Mediadores da Inflamação/antagonistas & inibidores , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/prevenção & controle , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
The serine synthesis pathway (SSP) involving metabolic enzymes phosphoglycerate dehydrogenase (PHGDH), phosphoserine aminotransferase 1 (PSAT1), and phosphoserine phosphatase (PSPH) drives intracellular serine biosynthesis and is indispensable for cancer cells to grow in serine-limiting environments. However, how SSP is regulated is not well understood. Here, we report that activating transcription factor 3 (ATF3) is crucial for transcriptional activation of SSP upon serine deprivation. ATF3 is rapidly induced by serine deprivation via a mechanism dependent on ATF4, which in turn binds to ATF4 and increases the stability of this master regulator of SSP. ATF3 also binds to the enhancers/promoters of PHGDH, PSAT1, and PSPH and recruits p300 to promote expression of these SSP genes. As a result, loss of ATF3 expression impairs serine biosynthesis and the growth of cancer cells in the serine-deprived medium or in mice fed with a serine/glycine-free diet. Interestingly, ATF3 expression positively correlates with PHGDH expression in a subset of TCGA cancer samples.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Neoplasias/patologia , Serina/biossíntese , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Vias Biossintéticas/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Nus , Neoplasias/metabolismo , Fosfoglicerato Desidrogenase/genética , Fosfoglicerato Desidrogenase/metabolismo , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Estabilidade Proteica , Serina/deficiência , Transaminases/genética , Transaminases/metabolismo , Transplante Heterólogo , Fatores de Transcrição de p300-CBP/metabolismoRESUMO
Psychological stress increases the risk of gastrointestinal (GI) tract diseases, which involve bidirectional communication of the GI and nerves systems. Acute stress leads to GI ulcers; however, the mechanism of the native cellular protection pathway, which safeguards tissue integrality and maintains GI homeostasis, remains to be investigated. In a mouse model of this study, restraint stress induced GI leakage, abnormal tight junction protein expression, and cell death of gut epithelial cells. The expression of activating transcription factor 3 (ATF3), a stress-responsive transcription factor, is upregulated in the GI tissues of stressed animals. ATF3-deficient mice displayed an exacerbated phenotype of GI injuries. These results suggested that, in response to stress, ATF3 is part of the native cellular protective pathway in the GI system, which could be a molecular target for managing psychological stress-induced GI tract diseases.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Gastroenteropatias/etiologia , Restrição Física , Estresse Psicológico/complicações , Fator 3 Ativador da Transcrição/deficiência , Animais , Caspase 3/metabolismo , Duodeno/efeitos dos fármacos , Duodeno/metabolismo , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Gastroenteropatias/sangue , Regulação da Expressão Gênica , Camundongos Endogâmicos C57BL , Camundongos Knockout , Inibidores da Bomba de Prótons/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Estresse Psicológico/sangue , Proteínas de Junções Íntimas/genética , Proteínas de Junções Íntimas/metabolismoRESUMO
Genome editing techniques have facilitated significant advances in our understanding of fundamental biological processes, and the Cre-Lox system has been instrumental in these achievements. Driving Cre expression specifically in injured neurons has not been previously possible: we sought to address this limitation in mice using a Cre-ERT2 construct driven by a reliable indicator of axotomy, activating transcription factor 3 (ATF3). When crossed with reporter mice, a significant amount of recombination was achieved (without tamoxifen treatment) in peripherally-projecting sensory, sympathetic, and motoneurons after peripheral nerve crush in hemizygotes (65-80% by 16 d) and was absent in uninjured neurons. Importantly, injury-induced recombination did not occur in Schwann cells distal to the injury, and with a knock-out-validated antibody we verified an absence of ATF3 expression. Functional recovery following sciatic nerve crush in ATF3-deficient mice (both hemizygotes and homozygotes) was delayed, indicating previously unreported haploinsufficiency. In a proof-of-principle experiment, we crossed the ATF3-CreERT2 line with a floxed phosphatase and tensin homolog (PTEN) line and show significantly improved axonal regeneration, as well as more complete recovery of neuromuscular function. We also demonstrate the utility of the ATF3-CreERT2 hemizygous line by characterizing recombination after lateral spinal hemisection (C8/T1), which identified specific populations of ascending spinal cord neurons (including putative spinothalamic and spinocerebellar) and descending supraspinal neurons (rubrospinal, vestibulospinal, reticulospinal and hypothalamic). We anticipate these mice will be valuable in distinguishing axotomized from uninjured neurons of several different classes (e.g., via reporter expression), and in probing the function of any number of genes as they relate to neuronal injury and regeneration.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Edição de Genes/métodos , Regulação da Expressão Gênica , Regeneração Nervosa , Traumatismos dos Nervos Periféricos , Recuperação de Função Fisiológica , Células de Schwann , Células Receptoras Sensoriais , Traumatismos da Medula Espinal , Fator 3 Ativador da Transcrição/deficiência , Animais , Axotomia , Comportamento Animal/fisiologia , Modelos Animais de Doenças , Estudos de Viabilidade , Expressão Gênica/genética , Integrases/metabolismo , Camundongos , Camundongos Transgênicos , PTEN Fosfo-Hidrolase/metabolismo , Estudo de Prova de Conceito , Células de Schwann/metabolismo , Nervo Isquiático/lesões , Células Receptoras Sensoriais/metabolismoRESUMO
c-Jun dimerization protein (JDP2) and Activating Transcription Factor 3 (ATF3) are closely related basic leucine zipper proteins. Transgenic mice with cardiac expression of either JDP2 or ATF3 showed maladaptive remodeling and cardiac dysfunction. Surprisingly, JDP2 knockout (KO) did not protect the heart following transverse aortic constriction (TAC). Instead, the JDP2 KO mice performed worse than their wild type (WT) counterparts. To test whether the maladaptive cardiac remodeling observed in the JDP2 KO mice is due to ATF3, ATF3 was removed in the context of JDP2 deficiency, referred as double KO mice (dKO). Mice were challenged by TAC, and followed by detailed physiological, pathological and molecular analyses. dKO mice displayed no apparent differences from WT mice under unstressed condition, except a moderate better performance in dKO male mice. Importantly, following TAC the dKO hearts showed low fibrosis levels, reduced inflammatory and hypertrophic gene expression and a significantly preserved cardiac function as compared with their WT counterparts in both genders. Consistent with these data, removing ATF3 resumed p38 activation in the JDP2 KO mice which correlates with the beneficial cardiac function. Collectively, mice with JDP2 and ATF3 double deficiency had reduced maladaptive cardiac remodeling and lower hypertrophy following TAC. As such, the worsening of the cardiac outcome found in the JDP2 KO mice is due to the elevated ATF3 expression. Simultaneous suppression of both ATF3 and JDP2 activity is highly beneficial for cardiac function in health and disease.
Assuntos
Fator 3 Ativador da Transcrição/deficiência , Proteínas Repressoras/deficiência , Remodelação Ventricular/fisiologia , Fator 3 Ativador da Transcrição/genética , Fator 3 Ativador da Transcrição/fisiologia , Animais , Cardiomegalia/genética , Cardiomegalia/patologia , Cardiomegalia/fisiopatologia , Feminino , Fibrose , Coração/fisiopatologia , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Contração Miocárdica/genética , Contração Miocárdica/fisiologia , Miocárdio/patologia , Proteínas Repressoras/genética , Proteínas Repressoras/fisiologia , Remodelação Ventricular/genéticaRESUMO
Billions of people have obesity-related metabolic syndromes such as diabetes and hyperlipidemia. Promoting the browning of white adipose tissue has been suggested as a potential strategy, but a drug still needs to be identified. Here, genetic deletion of activating transcription factor 3 (ATF3-/- ) in mice under a high-fat diet (HFD) resulted in obesity and insulin resistance, which was abrogated by virus-mediated ATF3 restoration. ST32da, a synthetic ATF3 inducer isolated from Salvia miltiorrhiza, promoted ATF3 expression to downregulate adipokine genes and induce adipocyte browning by suppressing the carbohydrate-responsive element-binding protein-stearoyl-CoA desaturase-1 axis. Furthermore, ST32da increased white adipose tissue browning and reduced lipogenesis in HFD-induced obese mice. The anti-obesity efficacy of oral ST32da administration was similar to that of the clinical drug orlistat. Our study identified the ATF3 inducer ST32da as a promising therapeutic drug for treating diet-induced obesity and related metabolic disorders.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Adipócitos Marrons/metabolismo , Obesidade/metabolismo , Células 3T3-L1 , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Adipócitos Marrons/patologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/patologia , Animais , Fármacos Antiobesidade/farmacologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Regulação da Temperatura Corporal/fisiologia , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Humanos , Resistência à Insulina , Lipogênese/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/genética , Obesidade/prevenção & controle , Orlistate/farmacologia , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Salvia miltiorrhiza/químicaRESUMO
The cellular and mechanistic bases underlying endothelial regeneration of adult large vessels have proven challenging to study. Using a reproducible in vivo aortic endothelial injury model, we characterized cellular dynamics underlying the regenerative process through a combination of multi-color lineage tracing, parabiosis, and single-cell transcriptomics. We found that regeneration is a biphasic process driven by distinct populations arising from differentiated endothelial cells. The majority of cells immediately adjacent to the injury site re-enter the cell cycle during the initial damage response, with a second phase driven by a highly proliferative subpopulation. Endothelial regeneration requires activation of stress response genes including Atf3, and aged aortas compromised in their reparative capacity express less Atf3. Deletion of Atf3 reduced endothelial proliferation and compromised the regeneration. These findings provide important insights into cellular dynamics and mechanisms that drive responses to large vessel injury.
Assuntos
Aorta/citologia , Células Endoteliais/citologia , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/metabolismo , Animais , Aorta/lesões , Aorta/metabolismo , Proliferação de Células , Células Endoteliais/metabolismo , Cinética , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Airborne particulate matter (PM) has been reported to be associated with a wide range of respiratory disorders. However, the mechanisms underlying PM-induced airway inflammation remain largely unknown. Generally, ATF3 negatively regulates pro-inflammatory cytokines production in response to TLR4 signaling. Here we first showed ATF3 has promoting effects in PM-induced airway inflammation in vitro an in vivo. We demonstrated PM significantly upregulated ATF3 expression in HBE cells and in mouse lung tissues. ATF3 siRNA markedly inhibited, while ATF3-recombinant over-expression plasmid significantly increased PM-induced IL-6 expression in cultured HBE cells, and PM-induced IL-6, CXCL2 expression as well as neutrophil infiltration, mucus over-production in the lung of ATF3-/- mice were all notably reduced relative to the wild-type littermates. Furthermore, we showed ATF3 mediated PM-induced inflammatory cytokines expression partly through NF-κB and AP-1 pathways. Our data further elucidates the mechanisms underlying PM-induced airway inflammation, and indicates ATF3 may function as different role in response to different stimuli.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Brônquios/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Material Particulado/toxicidade , Pneumonia/metabolismo , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Brônquios/metabolismo , Brônquios/patologia , Linhagem Celular , Quimiocina CXCL2/metabolismo , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Interleucina-6/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Muco/metabolismo , NF-kappa B/metabolismo , Infiltração de Neutrófilos/efeitos dos fármacos , Pneumonia/induzido quimicamente , Pneumonia/genética , Pneumonia/patologia , Interferência de RNA , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição AP-1/metabolismo , TransfecçãoRESUMO
AIMS: Obesity and type 2 diabetes (T2D) trigger a harmful stress-induced cardiac remodeling process known as cardiomyopathy. These diseases represent a serious and widespread health problem in the Western world; however the underlying molecular basis is not clear. ATF3 is an 'immediate early' gene whose expression is highly and transiently induced in response to multiple stressors such as metabolic, oxidative, endoplasmic reticulum and inflammation, stressors that are involved in T2D cardiomyopathy. The role of ATF3 in diabetic cardiomyopathy is currently unknown. Our research has aimed to study the effect of ATF3 expression on cardiomyocytes, heart function and glucose homeostasis in an obesity-induced T2D mouse model. METHODS AND RESULTS: We used wild type mice (WT) as well as mutant mice with a cardiac-specific ATF3 deficiency (ATF3-cKO). Mice were fed a high-fat diet (HFD) for 15 weeks. HFD induced high ATF3 expression in cardiomyocytes. Mice were examined for cardiac remodeling processes and the diabetic state was assessed. HFD-fed ATF3-cKO mice exhibited severe cardiac fibrosis, higher levels of heart hypertrophic markers, increased inflammation and worse cardiac function, as compared to WT mice. Interestingly, HFD-fed ATF3-cKO mice display increased hyperglycemia and reduced glucose tolerance, despite higher blood insulin levels, as compared to HFD-fed WT mice. Elevated levels of the cardiac inflammatory cytokines IL-6 and TNFα leading to impaired insulin signalling may partially explain the peripheral glucose intolerance. CONCLUSIONS: Cardiac ATF3 has a protective role in dampening the HFD-induced cardiac remodeling processes. ATF3 exerts both local and systemic effects related to T2D-induced cardiomyopathy. This study provides a strong relationship between heart remodeling processes and blood glucose homeostasis.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Cardiomiopatias Diabéticas/sangue , Miócitos Cardíacos/metabolismo , Remodelação Ventricular , Fator 3 Ativador da Transcrição/deficiência , Fator 3 Ativador da Transcrição/genética , Animais , Cardiomegalia/sangue , Cardiomegalia/metabolismo , Cardiomegalia/patologia , Células Cultivadas , Diabetes Mellitus Tipo 2/etiologia , Cardiomiopatias Diabéticas/etiologia , Cardiomiopatias Diabéticas/patologia , Cardiomiopatias Diabéticas/fisiopatologia , Dieta Hiperlipídica , Modelos Animais de Doenças , Ácidos Graxos não Esterificados/farmacologia , Fibrose , Predisposição Genética para Doença , Homeostase , Mediadores da Inflamação/metabolismo , Insulina/sangue , Integrases/genética , Interleucina-6/sangue , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Cadeias Pesadas de Miosina/genética , Fenótipo , Regiões Promotoras Genéticas , Fator de Necrose Tumoral alfa/sangue , Remodelação Ventricular/efeitos dos fármacosRESUMO
RATIONALE: Pressure overload induces adaptive remodeling processes in the heart. However, when pressure overload persists, adaptive changes turn into maladaptive alterations leading to cardiac hypertrophy and heart failure. ATF3 is a stress inducible transcription factor that is transiently expressed following neuroendocrine stimulation. However, its role in chronic pressure overload dependent cardiac hypertrophy is currently unknown. OBJECTIVE: The objective of the study was to study the role of ATF3 in chronic pressure overload dependent cardiac remodeling processes. METHODS AND RESULTS: Pressure overload was induced by phenylephrine (PE) mini-osmotic pumps in various mice models of whole body, cardiac specific, bone marrow (BM) specific and macrophage specific ATF3 ablations. We show that ATF3-KO mice exhibit a significantly reduced expression of cardiac remodeling markers following chronic pressure overload. Consistently, the lack of ATF3 specifically in either cardiomyocytes or BM derived cells blunts the hypertrophic response to PE infusion. A unique cross-talk between cardiomyocytes and macrophages was identified. Cardiomyocytes induce an ATF3 dependent induction of an inflammatory response leading to macrophage recruitment to the heart. Adoptive transfer of wild type macrophages, but not ATF3-KO derived macrophages, into wild type mice potentiates maladaptive response to PE infusion. CONCLUSIONS: Collectively, this study places ATF3 as a key regulator in promoting pressure overload induced cardiac hypertrophy through a cross-talk between cardiomyocytes and macrophages. Inhibiting this cross-talk may serve as a useful approach to blunt maladaptive remodeling processes in the heart.
Assuntos
Fator 3 Ativador da Transcrição/deficiência , Cardiomegalia/metabolismo , Macrófagos/metabolismo , Miócitos Cardíacos/metabolismo , Remodelação Ventricular/fisiologia , Fator 3 Ativador da Transcrição/biossíntese , Animais , Cardiomegalia/patologia , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miócitos Cardíacos/patologiaRESUMO
Macrophages play an essential role in the innate immune response to infection and tissue injury. However, excessive macrophage activation may also significantly contribute to chronic inflammatory diseases. The Toll-like receptor (TLR) family are key regulators of innate immune responses in macrophages, and they are able to promote their survival and resistance against apoptosis. We, and others, have shown that the adaptive response gene, activating transcription factor 3 (ATF3), acts as a negative regulator of TLR signaling by repressing transcription of pro-inflammatory cytokines in primary mouse macrophages. Here, we describe a novel role for ATF3 as a component of TLR-mediated survival in macrophages. ATF3-deficient bone marrow macrophages show reduced survival in response to a range of TLR ligands and significantly higher apoptotic rates were observed in response to lipopolysaccharide, indicating that ATF3 is required to suppress apoptosis in macrophages. Furthermore, we show that ATF3 lies downstream of JNK signaling after TLR engagement, resulting in repression of pro-apoptotic Bak and Bax transcription.