RESUMEN
Transcriptional regulation of catabolic pathways is a central mechanism by which cells respond to physiological cues to generate the energy required for anabolic pathways, transport of molecules and mechanical work. Nuclear receptors are members of a superfamily of transcription factors that transduce hormonal, nutrient, metabolite and redox signals into specific metabolic gene programmes, and thus hold a major status as regulators of cellular energy generation. Nuclear receptors also regulate the expression of genes involved in cellular processes that are implicated in energy production, including mitochondrial biogenesis and autophagy. Recent advances in genome-wide approaches have considerably expanded the repertoire of both nuclear receptors and metabolic genes under their direct transcriptional control. To fine-tune the expression of their target genes, nuclear receptors must act cooperatively with other transcription factors and coregulator proteins, integrate signals from key metabolic sensory systems such as the AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) complexes and synchronize their activities with the biological clock. Therefore, nuclear receptors must function as more than molecular switches for small lipophilic ligands - as initially ascribed - but rather must be capable of orchestrating a large ensemble of input signals. Therefore, a primary role for several nuclear receptors is to serve as the focal point of transcriptional hubs in energy metabolism: their molecular task is to receive and transduce multiple systemic and intracellular metabolic signals to maintain energy homeostasis from individual cells to the whole organism.
Asunto(s)
Proteínas Quinasas Activadas por AMP , Serina-Treonina Quinasas TOR , Proteínas Quinasas Activadas por AMP/metabolismo , Ligandos , Serina-Treonina Quinasas TOR/metabolismo , Metabolismo Energético/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Receptores Citoplasmáticos y Nucleares/genética , SirolimusRESUMEN
Excessive reactive oxygen species (ROS) can cause oxidative stress and consequently cell injury contributing to a wide range of diseases. Addressing the critical gaps in our understanding of the adaptive molecular events downstream ROS provocation holds promise for the identification of druggable metabolic vulnerabilities. Here, we unveil a direct molecular link between the activity of two estrogen-related receptor (ERR) isoforms and the control of glutamine utilization and glutathione antioxidant production. ERRα down-regulation restricts glutamine entry into the TCA cycle, while ERRγ up-regulation promotes glutamine-driven glutathione production. Notably, we identify increased ERRγ expression/activation as a hallmark of oxidative stress triggered by mitochondrial disruption or chemotherapy. Enhanced tumor antioxidant capacity is an underlying feature of human breast cancer (BCa) patients that respond poorly to treatment. We demonstrate that pharmacological inhibition of ERRγ with the selective inverse agonist GSK5182 increases antitumor efficacy of the chemotherapeutic paclitaxel on poor outcome BCa tumor organoids. Our findings thus underscore the ERRs as novel redox sensors and effectors of a ROS defense program and highlight the potential therapeutic advantage of exploiting ERRγ inhibitors for the treatment of BCa and other diseases where oxidative stress plays a central role.
Asunto(s)
Neoplasias de la Mama/fisiopatología , Resistencia a Antineoplásicos/efectos de los fármacos , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Receptores de Estrógenos/metabolismo , Transducción de Señal/fisiología , Animales , Antineoplásicos/farmacología , Técnicas Biosensibles , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Glutamina/metabolismo , Glutatión/metabolismo , Humanos , Ratones , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Paclitaxel/farmacología , Receptores de Estrógenos/genética , Rotenona/farmacología , Tamoxifeno/análogos & derivados , Tamoxifeno/farmacología , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
GCN2 (general control nonderepressible 2) is a serine/threonine-protein kinase that controls messenger RNA translation in response to amino acid availability and ribosome stalling. Here, we show that GCN2 controls erythrocyte clearance and iron recycling during stress. Our data highlight the importance of liver macrophages as the primary cell type mediating these effects. During different stress conditions, such as hemolysis, amino acid deficiency or hypoxia, GCN2 knockout (GCN2-/-) mice displayed resistance to anemia compared with wild-type (GCN2+/+) mice. GCN2-/- liver macrophages exhibited defective erythrophagocytosis and lysosome maturation. Molecular analysis of GCN2-/- cells demonstrated that the ATF4-NRF2 pathway is a critical downstream mediator of GCN2 in regulating red blood cell clearance and iron recycling.
Asunto(s)
Aminoácidos , Eritrocitos , Hierro , Hígado , Macrófagos , Proteínas Serina-Treonina Quinasas , Factor de Transcripción Activador 4/metabolismo , Aminoácidos/deficiencia , Aminoácidos/metabolismo , Anemia/metabolismo , Animales , Citofagocitosis , Eritrocitos/metabolismo , Eliminación de Gen , Hemólisis , Hipoxia/metabolismo , Hierro/metabolismo , Hígado/citología , Lisosomas/metabolismo , Macrófagos/metabolismo , Ratones , Ratones Noqueados , Factor 2 Relacionado con NF-E2/metabolismo , Proteínas Serina-Treonina Quinasas/deficiencia , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Estrés FisiológicoRESUMEN
Androgen receptor (AR) signaling reprograms cellular metabolism to support prostate cancer (PCa) growth and survival. Another key regulator of cellular metabolism is mTOR, a kinase found in diverse protein complexes and cellular localizations, including the nucleus. However, whether nuclear mTOR plays a role in PCa progression and participates in direct transcriptional cross-talk with the AR is unknown. Here, via the intersection of gene expression, genomic, and metabolic studies, we reveal the existence of a nuclear mTOR-AR transcriptional axis integral to the metabolic rewiring of PCa cells. Androgens reprogram mTOR-chromatin associations in an AR-dependent manner in which activation of mTOR-dependent metabolic gene networks is essential for androgen-induced aerobic glycolysis and mitochondrial respiration. In models of castration-resistant PCa cells, mTOR was capable of transcriptionally regulating metabolic gene programs in the absence of androgens, highlighting a potential novel castration resistance mechanism to sustain cell metabolism even without a functional AR. Remarkably, we demonstrate that increased mTOR nuclear localization is indicative of poor prognosis in patients, with the highest levels detected in castration-resistant PCa tumors and metastases. Identification of a functional mTOR targeted multigene signature robustly discriminates between normal prostate tissues, primary tumors, and hormone refractory metastatic samples but is also predictive of cancer recurrence. This study thus underscores a paradigm shift from AR to nuclear mTOR as being the master transcriptional regulator of metabolism in PCa.
Asunto(s)
Regulación Neoplásica de la Expresión Génica/genética , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/fisiopatología , Receptores Androgénicos/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Andrógenos/metabolismo , Núcleo Celular/metabolismo , ADN/metabolismo , Progresión de la Enfermedad , Humanos , Masculino , Unión Proteica , Serina-Treonina Quinasas TOR/genética , Transcripción GenéticaRESUMEN
The orphan nuclear receptor estrogen-related receptor α (ERRα; NR3B1) is a key metabolic regulator, but its function in regulating inflammation remains largely unknown. Here, we demonstrate that ERRα negatively regulates Toll-like receptor (TLR)-induced inflammation by promoting Tnfaip3 transcription and fine-tuning of metabolic reprogramming in macrophages. ERRα-deficient (Esrra(-/-)) mice showed increased susceptibility to endotoxin-induced septic shock, leading to more severe pro-inflammatory responses than control mice. ERRα regulated macrophage inflammatory responses by directly binding the promoter region of Tnfaip3, a deubiquitinating enzyme in TLR signaling. In addition, Esrra(-/-) macrophages showed an increased glycolysis, but impaired mitochondrial respiratory function and biogenesis. Further, ERRα was required for the regulation of NF-κB signaling by controlling p65 acetylation via maintenance of NAD(+) levels and sirtuin 1 activation. These findings unravel a previously unappreciated role for ERRα as a negative regulator of TLR-induced inflammatory responses through inducing Tnfaip3 transcription and controlling the metabolic reprogramming.
Asunto(s)
Cisteína Endopeptidasas/biosíntesis , Inflamación/inmunología , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Macrófagos/metabolismo , Receptores de Estrógenos/genética , Receptor Toll-Like 4/inmunología , Acetilación , Animales , Calcio/metabolismo , Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/metabolismo , Células Cultivadas , Cisteína Endopeptidasas/genética , Activación Enzimática/genética , Glucólisis/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Lipopolisacáridos , Macrófagos/inmunología , Ratones , Ratones Noqueados , Factor 88 de Diferenciación Mieloide/metabolismo , NAD/metabolismo , Fosforilación Oxidativa , Regiones Promotoras Genéticas/genética , Regiones Promotoras Genéticas/inmunología , Choque Séptico/inmunología , Transducción de Señal , Sirtuina 1/metabolismo , Factor 6 Asociado a Receptor de TNF/metabolismo , Factor de Transcripción ReIA/metabolismo , Transcripción Genética/genética , Proteína 3 Inducida por el Factor de Necrosis Tumoral alfa , Ubiquitinación , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
The tumor suppressor folliculin (FLCN) forms a repressor complex with AMP-activated protein kinase (AMPK). Given that AMPK is a master regulator of cellular energy homeostasis, we generated an adipose-specific Flcn (Adipoq-FLCN) knockout mouse model to investigate the role of FLCN in energy metabolism. We show that loss of FLCN results in a complete metabolic reprogramming of adipose tissues, resulting in enhanced oxidative metabolism. Adipoq-FLCN knockout mice exhibit increased energy expenditure and are protected from high-fat diet (HFD)-induced obesity. Importantly, FLCN ablation leads to chronic hyperactivation of AMPK, which in turns induces and activates two key transcriptional regulators of cellular metabolism, proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) and estrogen-related receptor α (ERRα). Together, the AMPK/PGC-1α/ERRα molecular axis positively modulates the expression of metabolic genes to promote mitochondrial biogenesis and activity. In addition, mitochondrial uncoupling proteins as well as other markers of brown fat are up-regulated in both white and brown FLCN-null adipose tissues, underlying the increased resistance of Adipoq-FLCN knockout mice to cold exposure. These findings identify a key role of FLCN as a negative regulator of mitochondrial function and identify a novel molecular pathway involved in the browning of white adipocytes and the activity of brown fat.
Asunto(s)
Tejido Adiposo Beige/metabolismo , Metabolismo Energético/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Proteínas Proto-Oncogénicas/genética , Receptores de Estrógenos/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Quinasas Activadas por AMP/genética , Animales , Frío , Activación Enzimática/genética , Regulación de la Expresión Génica/genética , Ratones , Ratones Noqueados , Obesidad/enzimología , Obesidad/genética , Oxidación-Reducción , Proteínas Proto-Oncogénicas/metabolismo , Receptores de Estrógenos/genética , Transducción de Señal , Proteínas Supresoras de Tumor/metabolismo , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
La-related protein 1 (LARP1) has been identified as a key translational inhibitor of terminal oligopyrimidine (TOP) mRNAs downstream of the nutrient sensing protein kinase complex, mTORC1. LARP1 exerts this inhibitory effect on TOP mRNA translation by binding to the mRNA cap and the adjacent 5'TOP motif, resulting in the displacement of the cap-binding protein eIF4E from TOP mRNAs. However, the involvement of additional signaling pathway in regulating LARP1-mediated inhibition of TOP mRNA translation is largely unexplored. In the present study, we identify a second nutrient sensing kinase GCN2 that converges on LARP1 to control TOP mRNA translation. Using chromatin-immunoprecipitation followed by massive parallel sequencing (ChIP-seq) analysis of activating transcription factor 4 (ATF4), an effector of GCN2 in nutrient stress conditions, in WT and GCN2 KO mouse embryonic fibroblasts, we determined that LARP1 is a GCN2-dependent transcriptional target of ATF4. Moreover, we identified GCN1, a GCN2 activator, participates in a complex with LARP1 on stalled ribosomes, suggesting a role for GCN1 in LARP1-mediated translation inhibition in response to ribosome stalling. Therefore, our data suggest that the GCN2 pathway controls LARP1 activity via two mechanisms: ATF4-dependent transcriptional induction of LARP1 mRNA and GCN1-mediated recruitment of LARP1 to stalled ribosomes.
Asunto(s)
Aminoácidos , Biosíntesis de Proteínas , Proteínas Serina-Treonina Quinasas , Secuencia de Oligopirimidina en la Región 5' Terminal del ARN , ARN Mensajero , Proteínas de Unión al ARN , Factor de Transcripción Activador 4/genética , Factor de Transcripción Activador 4/metabolismo , Aminoácidos/metabolismo , Animales , Técnicas de Cultivo de Célula , Inmunoprecipitación de Cromatina , Factor 4E Eucariótico de Iniciación/metabolismo , Fibroblastos , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones , Ratones Noqueados , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismoRESUMEN
Whole-body metabolic homeostasis is tightly controlled by hormone-like factors with systemic or paracrine effects that are derived from nonendocrine organs, including adipose tissue (adipokines) and liver (hepatokines). Fibroblast growth factor 21 (FGF21) is a hormone-like protein, which is emerging as a major regulator of whole-body metabolism and has therapeutic potential for treating metabolic syndrome. However, the mechanisms that control FGF21 levels are not fully understood. Herein, we demonstrate that FGF21 production in the liver is regulated via a posttranscriptional network consisting of the CCR4-NOT deadenylase complex and RNA-binding protein tristetraprolin (TTP). In response to nutrient uptake, CCR4-NOT cooperates with TTP to degrade AU-rich mRNAs that encode pivotal metabolic regulators, including FGF21. Disruption of CCR4-NOT activity in the liver, by deletion of the catalytic subunit CNOT6L, increases serum FGF21 levels, which ameliorates diet-induced metabolic disorders and enhances energy expenditure without disrupting bone homeostasis. Taken together, our study describes a hepatic CCR4-NOT/FGF21 axis as a hitherto unrecognized systemic regulator of metabolism and suggests that hepatic CCR4-NOT may serve as a target for devising therapeutic strategies in metabolic syndrome and related morbidities.
Asunto(s)
Exorribonucleasas , Factores de Crecimiento de Fibroblastos , Hepatocitos , Homeostasis , Ribonucleasas , Animales , Células Cultivadas , Dieta Alta en Grasa , Exorribonucleasas/genética , Exorribonucleasas/metabolismo , Factores de Crecimiento de Fibroblastos/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Hepatocitos/metabolismo , Hepatocitos/fisiología , Homeostasis/genética , Homeostasis/fisiología , Humanos , Hígado/química , Hígado/metabolismo , Hígado/patología , Síndrome Metabólico/metabolismo , Ratones , Ratones Transgénicos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ribonucleasas/genética , Ribonucleasas/metabolismoRESUMEN
Translational control of gene expression plays a key role during the early phases of embryonic development. Here we describe a transcriptional regulator of mouse embryonic stem cells (mESCs), Yin-yang 2 (YY2), that is controlled by the translation inhibitors, Eukaryotic initiation factor 4E-binding proteins (4E-BPs). YY2 plays a critical role in regulating mESC functions through control of key pluripotency factors, including Octamer-binding protein 4 (Oct4) and Estrogen-related receptor-ß (Esrrb). Importantly, overexpression of YY2 directs the differentiation of mESCs into cardiovascular lineages. We show that the splicing regulator Polypyrimidine tract-binding protein 1 (PTBP1) promotes the retention of an intron in the 5'-UTR of Yy2 mRNA that confers sensitivity to 4E-BP-mediated translational suppression. Thus, we conclude that YY2 is a major regulator of mESC self-renewal and lineage commitment and document a multilayer regulatory mechanism that controls its expression.
Asunto(s)
Empalme Alternativo/fisiología , Diferenciación Celular , Autorrenovación de las Células/fisiología , Células Madre Embrionarias/metabolismo , Regulación del Desarrollo de la Expresión Génica , Factores de Transcripción/metabolismo , Animales , Blastocisto/metabolismo , Proteínas Portadoras/metabolismo , Linaje de la Célula , Autorrenovación de las Células/genética , Ribonucleoproteínas Nucleares Heterogéneas/genética , Intrones , Ratones , Ratones Noqueados , Modelos Biológicos , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Fosfoproteínas , Proteína de Unión al Tracto de Polipirimidina/genética , Biosíntesis de Proteínas/genética , ARN Mensajero/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Receptores de Estrógenos/metabolismo , Factores de Transcripción/genética , Transcripción Genética/fisiología , Factor de Transcripción YY1/metabolismoRESUMEN
Estrogen-related receptor alpha (ERRalpha) and proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) play central roles in the transcriptional control of energy homeostasis, but little is known about factors regulating their activity. Here we identified the homeobox protein prospero-related homeobox 1 (Prox1) as one such factor. Prox1 interacts with ERRalpha and PGC-1alpha, occupies promoters of metabolic genes on a genome-wide scale, and inhibits the activity of the ERRalpha/PGC-1alpha complex. DNA motif analysis suggests that Prox1 interacts with the genome through tethering to ERRalpha and other factors. Importantly, ablation of Prox1 and ERRalpha have opposite effects on the respiratory capacity of liver cells, revealing an unexpected role for Prox1 in the control of energy homeostasis.
Asunto(s)
Metabolismo Energético , Proteínas de Homeodominio/metabolismo , Receptores de Estrógenos/metabolismo , Transactivadores/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Regulación de la Expresión Génica , Estudio de Asociación del Genoma Completo , Células Hep G2 , Proteínas de Homeodominio/genética , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Receptores de Estrógenos/genética , Regulón/genética , Transactivadores/genética , Factores de Transcripción , Proteínas Supresoras de Tumor/genética , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Several physiopathological processes require orientated cellular migration. This phenomenon highly depends on members of the RHO family of GTPases. Both excessive and deficient RHO activity impair directional migration. A tight control is thus exerted on these proteins through the regulation of their activation and of their stability. Here we show that the estrogen-related receptor α (ERRα) directly activates the expression of TNFAIP1, the product of which [BTB/POZ domain-containing adapter for Cullin3-mediated RhoA degradation 2 (BACURD2)] regulates RHOA protein turnover. Inactivation of the receptor leads to enhanced RHOA stability and activation. This results in cell disorientation, increased actin network, and inability to form a lamellipodium at the migration edge. As a consequence, directional migration, but not cell motility per se, is impaired in the absence of the receptor, under pathological as well as physiological conditions. Altogether, our results show that the control exerted by ERRα on RHOA stability is required for directional migration.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Movimiento Celular , Receptores de Estrógenos/metabolismo , Proteína de Unión al GTP rhoA/metabolismo , Actinas/metabolismo , Animales , Línea Celular Tumoral , Proteínas Cullin/metabolismo , Matriz Extracelular/metabolismo , Humanos , Macrófagos/citología , Macrófagos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Invasividad Neoplásica , Metástasis de la Neoplasia , Pronóstico , Estabilidad Proteica , Estructura Terciaria de Proteína , Proteínas/metabolismo , Cicatrización de Heridas , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Estrogen-related receptor α (ERRα) is a key regulator of mitochondrial function and metabolism essential for energy-driven cellular processes in both normal and cancer cells. ERRα has also been shown to mediate bone-derived macrophage activation by proinflammatory cytokines. However, the role of ERRα in cancer in which inflammation acts as a tumor promoter has yet to be investigated. Herein we show that global loss of ERRα accelerates the development of diethylnitrosamine (DEN)-induced hepatocellular carcinoma. Biochemical and metabolomics studies revealed that loss of ERRα promotes hepatocyte necrosis over apoptosis in response to DEN due to a deficiency in energy production. We further show that increased hepatocyte death and associated compensatory proliferation observed in DEN-injured ERRα-null livers is concomitant with increased nuclear factor κB (NF-κB)-dependent transcriptional control of cytokine expression in Kupffer cells. In particular, we demonstrate that loss of ERRα-dependent regulation of the NF-κB inhibitor IκBα leads to enhanced NF-κB activity and cytokine gene activation. Our work thus shows that global loss of ERRα activity promotes hepatocellular carcinoma by independent but synergistic mechanisms in hepatocytes and Kupffer cells, implying that pharmacological manipulation of ERRα activity may have a significant clinical impact on carcinogen-induced cancers.
Asunto(s)
Carcinogénesis/metabolismo , Hepatocitos/patología , Neoplasias Hepáticas/metabolismo , Receptores de Estrógenos/deficiencia , Animales , Western Blotting , Línea Celular Tumoral , Inmunoprecipitación de Cromatina , Cromatografía Liquida , Cartilla de ADN/genética , Dietilnitrosamina/administración & dosificación , Dietilnitrosamina/toxicidad , Proteínas I-kappa B/metabolismo , Inmunohistoquímica , Macrófagos del Hígado , Neoplasias Hepáticas/inducido químicamente , Metabolómica , Ratones , Ratones Noqueados , Inhibidor NF-kappaB alfa , FN-kappa B/metabolismo , Necrosis , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Estrógenos/genética , Espectrometría de Masas en Tándem , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
The identification of the estrogen-related receptors (ERRs) as the first orphan nuclear receptors ignited a new era in molecular endocrinology, which led to the discovery of new ligand-dependent response systems. Although ERR subfamily members have yet to be associated with a natural ligand, the characterization of these orphan receptors has demonstrated that they occupy a strategic node in the transcriptional control of cellular energy metabolism. In particular, ERRs are required for the response to various environmental challenges that require high energy levels by the organism. As central regulators of energy homeostasis, ERRs may also be implicated in the etiology of metabolic disorders, such as type 2 diabetes and metabolic syndrome. Here, we review the recent evidence that further highlights the role of ERRs in metabolic control, particularly in liver and skeletal muscle, and their likely involvement in metabolic diseases. Consequently, we also explore the promises and pitfalls of ERRs as potential therapeutic targets.
Asunto(s)
Enfermedades Metabólicas/metabolismo , Receptores de Estrógenos/metabolismo , Animales , Homeostasis/fisiología , Humanos , Ligandos , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Retinoic acid is a potent differentiation and antiproliferative agent of breast cancer cells, and one of its receptors, retinoic acid receptor ß (RARß), has been proposed to act as a tumor suppressor. In contrast, we report herein that inactivation of Rarb in the mouse results in a protective effect against ErbB2-induced mammary gland tumorigenesis. Strikingly, tissue recombination experiments indicate that the presence of Rarb in the stromal compartment is essential for the growth of mammary carcinoma. Ablation of Rarb leads to a remodeling of the stroma during tumor progression that includes a decrease in angiogenesis, in the recruitment of inflammatory cells, and in the number myofibroblasts. In agreement with this finding, we observed that a markedly reduced expression of chemokine (C-X-C motif) ligand 12 (Cxcl12) in the stroma of Rarb-null mice is accompanied by a decrease in the CXCL12/chemokine C-X-C receptor 4 (CXCR4)/ErbB2 signaling axis in the tumors. Relevance to the human disease is underlined by the finding that gene-expression profiling of the Rarb-deficient mammary stromal compartment identified an ortholog RARß signature in human microdissected breast tissues that differentiates tumor from normal stroma. Our study thus implicates RARß in promoting tumorigenesis and suggests that retinoid-based approaches for the prevention and treatment of breast cancer should be redesigned.
Asunto(s)
Regulación Neoplásica de la Expresión Génica , Glándulas Mamarias Animales/metabolismo , Receptores de Ácido Retinoico/metabolismo , Células del Estroma/citología , Animales , Quimiocina CXCL12/metabolismo , Femenino , Ratones , Ratones Transgénicos , Oncogenes , Receptor ErbB-2/metabolismo , Receptores CXCR4/metabolismo , Retinoides/química , Transducción de SeñalRESUMEN
IRF8 (Interferon Regulatory Factor 8) plays an important role in defenses against intracellular pathogens, including several aspects of myeloid cells function. It is required for ontogeny and maturation of macrophages and dendritic cells, for activation of anti-microbial defenses, and for production of the Th1-polarizing cytokine interleukin-12 (IL-12) in response to interferon gamma (IFNγ) and protection against infection with Mycobacterium tuberculosis. The transcriptional programs and cellular pathways that are regulated by IRF8 in response to IFNγ and that are important for defenses against M. tuberculosis are poorly understood. These were investigated by transcript profiling and chromatin immunoprecipitation on microarrays (ChIP-chip). Studies in primary macrophages identified 368 genes that are regulated by IRF8 in response to IFNγ/CpG and that behave as stably segregating expression signatures (eQTLs) in F2 mice fixed for a wild-type or mutant allele at IRF8. A total of 319 IRF8 binding sites were identified on promoters genome-wide (ChIP-chip) in macrophages treated with IFNγ/CpG, defining a functional G/AGAAnTGAAA motif. An analysis of the genes bearing a functional IRF8 binding site, and showing regulation by IFNγ/CpG in macrophages and/or in M. tuberculosis-infected lungs, revealed a striking enrichment for the pathways of antigen processing and presentation, including multiple structural and enzymatic components of the Class I and Class II MHC (major histocompatibility complex) antigen presentation machinery. Also significantly enriched as IRF8 targets are the group of endomembrane- and phagosome-associated small GTPases of the IRG (immunity-related GTPases) and GBP (guanylate binding proteins) families. These results identify IRF8 as a key regulator of early response pathways in myeloid cells, including phagosome maturation, antigen processing, and antigen presentation by myeloid cells.
Asunto(s)
Presentación de Antígeno , Factores Reguladores del Interferón/inmunología , Pulmón/microbiología , Células Mieloides/inmunología , Tuberculosis Pulmonar/inmunología , Alelos , Animales , Sitios de Unión , Western Blotting , Línea Celular , Inmunoprecipitación de Cromatina , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Femenino , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Genotipo , Factores Reguladores del Interferón/genética , Factores Reguladores del Interferón/metabolismo , Interferón gamma/inmunología , Pulmón/inmunología , Pulmón/metabolismo , Complejo Mayor de Histocompatibilidad , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/inmunología , Células Mieloides/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Regiones Promotoras Genéticas , Tuberculosis Pulmonar/genética , Tuberculosis Pulmonar/microbiologíaRESUMEN
Metabolic homeostasis and circadian rhythms are closely intertwined biological processes. Nuclear receptors, as sensors of hormonal and nutrient status, are actively implicated in maintaining this physiological relationship. Although the orphan nuclear receptor estrogen-related receptor α (ERRα, NR3B1) plays a central role in the control of energy metabolism and its expression is known to be cyclic in the liver, its role in temporal control of metabolic networks is unknown. Here we report that ERRα directly regulates all major components of the molecular clock. ERRα-null mice also display deregulated locomotor activity rhythms and circadian period lengths under free-running conditions, as well as altered circulating diurnal bile acid and lipid profiles. In addition, the ERRα-null mice exhibit time-dependent hypoglycemia and hypoinsulinemia, suggesting a role for ERRα in modulating insulin sensitivity and glucose handling during the 24-hour light/dark cycle. We also provide evidence that the newly identified ERRα corepressor PROX1 is implicated in rhythmic control of metabolic outputs. To help uncover the molecular basis of these phenotypes, we performed genome-wide location analyses of binding events by ERRα, PROX1, and BMAL1, an integral component of the molecular clock. These studies revealed the existence of transcriptional regulatory loops among ERRα, PROX1, and BMAL1, as well as extensive overlaps in their target genes, implicating these three factors in the control of clock and metabolic gene networks in the liver. Genomic convergence of ERRα, PROX1, and BMAL1 transcriptional activity thus identified a novel node in the molecular circuitry controlling the daily timing of metabolic processes.
Asunto(s)
Proteínas de Homeodominio/metabolismo , Hígado/metabolismo , Receptores de Estrógenos/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Factores de Transcripción ARNTL/genética , Factores de Transcripción ARNTL/metabolismo , Animales , Ácidos y Sales Biliares/sangre , Glucemia/análisis , Western Blotting , Proteínas CLOCK/metabolismo , Células COS , Chlorocebus aethiops , Colesterol/sangre , Ritmo Circadiano , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Gluconeogénesis , Glucólisis , Células Hep G2 , Proteínas de Homeodominio/genética , Homeostasis , Humanos , Insulina/sangre , Hígado/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Actividad Motora , Fotoperiodo , Regiones Promotoras Genéticas , Unión Proteica , Interferencia de ARN , Receptores de Estrógenos/genética , Triglicéridos/sangre , Proteínas Supresoras de Tumor/genética , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Stimulation of resting CD4(+) T lymphocytes leads to rapid proliferation and differentiation into effector (Teff) or inducible regulatory (Treg) subsets with specific functions to promote or suppress immunity. Importantly, Teff and Treg use distinct metabolic programs to support subset specification, survival, and function. Here, we describe that the orphan nuclear receptor estrogen-related receptor-α (ERRα) regulates metabolic pathways critical for Teff. Resting CD4(+) T cells expressed low levels of ERRα protein that increased on activation. ERRα deficiency reduced activated T-cell numbers in vivo and cytokine production in vitro but did not seem to modulate immunity through inhibition of activating signals or viability. Rather, ERRα broadly affected metabolic gene expression and glucose metabolism essential for Teff. In particular, up-regulation of Glut1 protein, glucose uptake, and mitochondrial processes were suppressed in activated ERRα(-/-) T cells and T cells treated with two chemically independent ERRα inhibitors or by shRNAi. Acute ERRα inhibition also blocked T-cell growth and proliferation. This defect appeared as a result of inadequate glucose metabolism, because provision of lipids, but not increased glucose uptake or pyruvate, rescued ATP levels and cell division. Additionally, we have shown that Treg requires lipid oxidation, whereas Teff uses glucose metabolism, and lipid addition selectively restored Treg--but not Teff--generation after acute ERRα inhibition. Furthermore, in vivo inhibition of ERRα reduced T-cell proliferation and Teff generation in both immunization and experimental autoimmune encephalomyelitis models. Thus, ERRα is a selective transcriptional regulator of Teff metabolism that may provide a metabolic means to modulate immunity.
Asunto(s)
Diferenciación Celular , Activación de Linfocitos , Receptores de Estrógenos/fisiología , Linfocitos T/inmunología , Animales , Proliferación Celular , Glucosa/metabolismo , Homeostasis , Ratones , Ratones Endogámicos C57BL , Mitocondrias/metabolismo , Reacción en Cadena de la Polimerasa , Interferencia de ARN , Receptores de Estrógenos/genética , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
mTOR is a serine/threonine kinase that controls prostate cancer cell growth in part by regulating gene programs associated with metabolic and cell proliferation pathways. mTOR-mediated control of gene expression can be achieved via phosphorylation of transcription factors, leading to changes in their cellular localization and activities. mTOR also directly associates with chromatin in complex with transcriptional regulators, including the androgen receptor (AR). Nuclear mTOR (nmTOR) has been previously shown to act as a transcriptional integrator of the androgen signaling pathway in association with the chromatin remodeling machinery, AR, and FOXA1. However, the contribution of cytoplasmic mTOR (cmTOR) and nmTOR and the role played by FOXA1 in this process remains to be explored. Herein, we engineered cells expressing mTOR tagged with nuclear localization and export signals dictating mTOR localization. Transcriptome profiling in AR-positive prostate cancer cells revealed that nmTOR generally downregulates a subset of the androgen response pathway independently of its kinase activity, while cmTOR upregulates a cell cycle-related gene signature in a kinase-dependent manner. Biochemical and genome-wide transcriptomic analyses demonstrate that nmTOR functionally interacts with AR and FOXA1. Ablation of FOXA1 reprograms the nmTOR cistrome and transcriptome of androgen responsive prostate cancer cells. This works highlights a transcriptional regulatory pathway in which direct interactions between nmTOR, AR and FOXA1 dictate a combinatorial role for these factors in the control of specific gene programs in prostate cancer cells. IMPLICATIONS: The finding that canonical and nuclear mTOR signaling pathways control distinct gene programs opens therapeutic opportunities to modulate mTOR activity in prostate cancer cells.
Asunto(s)
Andrógenos , Neoplasias de la Próstata , Humanos , Masculino , Andrógenos/metabolismo , Línea Celular Tumoral , Cromatina , Regulación Neoplásica de la Expresión Génica , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
OBJECTIVES: Estrogen-related-receptor α (ERRα) plays a critical role in the transcriptional regulation of cellular bioenergetics and metabolism, and perturbations in its activity have been associated with metabolic diseases. While several coactivators and corepressors of ERRα have been identified to date, a knowledge gap remains in understanding the extent to which ERRα cooperates with coregulators in the control of gene expression. Herein, we mapped the primary chromatin-bound ERRα interactome in mouse liver. METHODS: RIME (Rapid Immuno-precipitation Mass spectrometry of Endogenous proteins) analysis using mouse liver samples from two circadian time points was used to catalog ERRα-interacting proteins on chromatin. The genomic crosstalk between ERRα and its identified cofactors in the transcriptional control of precise gene programs was explored through cross-examination of genome-wide binding profiles from chromatin immunoprecipitation-sequencing (ChIP-seq) studies. The dynamic interplay between ERRα and its newly uncovered cofactor Host cell factor C1 (HCFC1) was further investigated by loss-of-function studies in hepatocytes. RESULTS: Characterization of the hepatic ERRα chromatin interactome led to the identification of 48 transcriptional interactors of which 42 were previously unknown including HCFC1. Interrogation of available ChIP-seq binding profiles highlighted oxidative phosphorylation (OXPHOS) under the control of a complex regulatory network between ERRα and multiple cofactors. While ERRα and HCFC1 were found to bind to a large set of common genes, only a small fraction showed their colocalization, found predominately near the transcriptional start sites of genes particularly enriched for components of the mitochondrial respiratory chain. Knockdown studies demonstrated inverse regulatory actions of ERRα and HCFC1 on OXPHOS gene expression ultimately dictating the impact of their loss-of-function on mitochondrial respiration. CONCLUSIONS: Our work unveils a repertoire of previously unknown transcriptional partners of ERRα comprised of chromatin modifiers and transcription factors thus advancing our knowledge of how ERRα regulates metabolic transcriptional programs.
Asunto(s)
Cromatina , Receptor Relacionado con Estrógeno ERRalfa , Hígado , Receptores de Estrógenos , Animales , Ratones , Cromatina/metabolismo , Cromatina/genética , Receptores de Estrógenos/metabolismo , Receptores de Estrógenos/genética , Hígado/metabolismo , Masculino , Ratones Endogámicos C57BL , Regulación de la Expresión Génica , Hepatocitos/metabolismoRESUMEN
Cellular senescence is a cell program induced by various stresses that leads to a stable proliferation arrest and to a senescence-associated secretory phenotype. Accumulation of senescent cells during age-related diseases participates in these pathologies and regulates healthy lifespan. Recent evidences point out a global dysregulated intracellular metabolism associated to senescence phenotype. Nonetheless, the functional contribution of metabolic homeostasis in regulating senescence is barely understood. In this work, we describe how the mevalonate pathway, an anabolic pathway leading to the endogenous biosynthesis of poly-isoprenoids, such as cholesterol, acts as a positive regulator of cellular senescence in normal human cells. Mechanistically, this mevalonate pathway-induced senescence is partly mediated by the downstream cholesterol biosynthetic pathway. This pathway promotes the transcriptional activity of ERRα that could lead to dysfunctional mitochondria, ROS production, DNA damage and a p53-dependent senescence. Supporting the relevance of these observations, increase of senescence in liver due to a high-fat diet regimen is abrogated in ERRα knockout mouse. Overall, this work unravels the role of cholesterol biosynthesis or level in the induction of an ERRα-dependent mitochondrial program leading to cellular senescence and related pathological alterations.