RESUMEN
The mitochondrial pyruvate dehydrogenase complex (PDC) translocates into the nucleus, facilitating histone acetylation by producing acetyl-CoA. We describe a noncanonical pathway for nuclear PDC (nPDC) import that does not involve nuclear pore complexes (NPCs). Mitochondria cluster around the nucleus in response to proliferative stimuli and tether onto the nuclear envelope (NE) via mitofusin-2 (MFN2)-enriched contact points. A decrease in nuclear MFN2 levels decreases mitochondria tethering and nPDC levels. Mitochondrial PDC crosses the NE and interacts with lamin A, forming a ring below the NE before crossing through the lamin layer into the nucleoplasm, in areas away from NPCs. Effective blockage of NPC trafficking does not decrease nPDC levels. The PDC-lamin interaction is maintained during cell division, when lamin depolymerizes and disassembles before reforming daughter nuclear envelopes, providing another pathway for nPDC entry during mitosis. Our work provides a different angle to understanding mitochondria-to-nucleus communication and nuclear metabolism.
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Núcleo Celular , Complejo Piruvato Deshidrogenasa , Acetilcoenzima A/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Laminas/metabolismo , Mitocondrias/genética , Mitocondrias/metabolismo , Membrana Nuclear/metabolismo , Complejo Piruvato Deshidrogenasa/genética , Complejo Piruvato Deshidrogenasa/metabolismoRESUMEN
DNA transcription, replication, and repair are regulated by histone acetylation, a process that requires the generation of acetyl-coenzyme A (CoA). Here, we show that all the subunits of the mitochondrial pyruvate dehydrogenase complex (PDC) are also present and functional in the nucleus of mammalian cells. We found that knockdown of nuclear PDC in isolated functional nuclei decreased the de novo synthesis of acetyl-CoA and acetylation of core histones. Nuclear PDC levels increased in a cell-cycle-dependent manner and in response to serum, epidermal growth factor, or mitochondrial stress; this was accompanied by a corresponding decrease in mitochondrial PDC levels, suggesting a translocation from the mitochondria to the nucleus. Inhibition of nuclear PDC decreased acetylation of specific lysine residues on histones important for G1-S phase progression and expression of S phase markers. Dynamic translocation of mitochondrial PDC to the nucleus provides a pathway for nuclear acetyl-CoA synthesis required for histone acetylation and epigenetic regulation.
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Acetilcoenzima A/biosíntesis , Núcleo Celular/metabolismo , Complejo Piruvato Deshidrogenasa/metabolismo , Ciclo Celular , Línea Celular Tumoral , Núcleo Celular/enzimología , Epigénesis Genética , Histonas/metabolismo , Humanos , Mitocondrias/enzimología , Mitocondrias/metabolismo , Transporte de ProteínasRESUMEN
BACKGROUND: The tumor suppressor and proapoptotic transcription factor P53 is induced (and activated) in several forms of heart failure, including cardiotoxicity and dilated cardiomyopathy; however, the precise mechanism that coordinates its induction with accessibility to its transcriptional promoter sites remains unresolved, especially in the setting of mature terminally differentiated (nonreplicative) cardiomyocytes. METHODS: Male and female control or TRIM35 (tripartite motif containing 35) overexpression adolescent (aged 1-3 months) and adult (aged 4-6 months) transgenic mice were used for all in vivo experiments. Primary adolescent or adult mouse cardiomyocytes were isolated from control or TRIM35 overexpression transgenic mice for all in vitro experiments. Adenovirus or small-interfering RNA was used for all molecular experiments to overexpress or knockdown, respectively, target genes in primary mouse cardiomyocytes. Patient dilated cardiomyopathy or nonfailing left ventricle samples were used for translational and mechanistic insight. Chromatin immunoprecipitation and DNA sequencing or quantitative real-time polymerase chain reaction (qPCR) was used to assess P53 binding to its transcriptional promoter targets, and RNA sequencing was used to identify disease-specific signaling pathways. RESULTS: Here, we show that E3-ubiquitin ligase TRIM35 can directly monoubiquitinate lysine-120 (K120) on histone 2B in postnatal mature cardiomyocytes. This epigenetic modification was sufficient to promote chromatin remodeling, accessibility of P53 to its transcriptional promoter targets, and elongation of its transcribed mRNA. We found that increased P53 transcriptional activity (in cardiomyocyte-specific Trim35 overexpression transgenic mice) was sufficient to initiate heart failure and these molecular findings were recapitulated in nonischemic human LV dilated cardiomyopathy samples. CONCLUSIONS: These findings suggest that TRIM35 and the K120Ub-histone 2B epigenetic modification are molecular features of cardiomyocytes that can collectively predict dilated cardiomyopathy pathogenesis.
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Insuficiencia Cardíaca , Histonas , Ratones Transgénicos , Miocitos Cardíacos , Proteína p53 Supresora de Tumor , Ubiquitinación , Animales , Femenino , Humanos , Masculino , Ratones , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/genética , Cardiomiopatía Dilatada/patología , Células Cultivadas , Insuficiencia Cardíaca/metabolismo , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/patología , Histonas/metabolismo , Ratones Endogámicos C57BL , Miocitos Cardíacos/metabolismo , Regiones Promotoras Genéticas , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
During evolution, cells acquired the ability to sense and adapt to varying environmental conditions, particularly in terms of fuel supply. Adaptation to fuel availability is crucial for major cell decisions and requires metabolic alterations and differential gene expression that are often epigenetically driven. A new mechanistic link between metabolic flux and regulation of gene expression is through moonlighting of metabolic enzymes in the nucleus. This facilitates delivery of membrane-impermeable or unstable metabolites to the nucleus, including key substrates for epigenetic mechanisms such as acetyl-CoA which is used in histone acetylation. This metabolism-epigenetics axis facilitates adaptation to a changing environment in normal (e.g., development, stem cell differentiation) and disease states (e.g., cancer), providing a potential novel therapeutic target.
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Núcleo Celular/enzimología , Núcleo Celular/genética , Regulación de la Expresión Génica , L-Lactato Deshidrogenasa/metabolismo , Transcripción Genética , HumanosRESUMEN
BACKGROUND: Pulmonary edema is a cardinal feature of heart failure but no quantitative tests are available in clinical practice. The goals of this study were to develop a simple cardiovascular magnetic resonance (CMR) approach for lung water quantification, to correlate CMR derived lung water with intra-cardiac pressures and to determine its prognostic significance. METHODS: Lung water density (LWD, %) was measured using a widely available single-shot fast spin-echo acquisition in two study cohorts. Validation Cohort: LWD was compared to left ventricular end-diastolic pressure or pulmonary capillary wedge pressure in 19 patients with heart failure undergoing cardiac catheterization. Prospective Cohort: LWD was measured in 256 subjects, including 121 with heart failure, 82 at-risk for heart failure and 53 healthy controls. Clinical outcomes were evaluated up to 1 year. RESULTS: Within the validation cohort, CMR LWD correlated to invasively measured left-sided filling pressures (R = 0.8, p < 0.05). In the prospective cohort, mean LWD was 16.6 ± 2.1% in controls, 17.9 ± 3.0% in patients at-risk and 19.3 ± 5.4% in patients with heart failure, p < 0.001. In patients with or at-risk for heart failure, LWD > 20.8% (mean + 2 standard deviations of healthy controls) was an independent predictor of death, hospitalization or emergency department visit within 1 year, hazard ratio 2.4 (1.1-5.1, p = 0.03). CONCLUSIONS: In patients with heart failure, increased CMR-derived lung water is associated with increased intra-cardiac filling pressures, and predicts 1 year outcomes. LWD could be incorporated in standard CMR scans.
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Agua Pulmonar Extravascular/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico por imagen , Pulmón/diagnóstico por imagen , Imagen por Resonancia Cinemagnética , Edema Pulmonar/diagnóstico por imagen , Adulto , Anciano , Estudios de Casos y Controles , Causas de Muerte , Progresión de la Enfermedad , Servicio de Urgencia en Hospital , Agua Pulmonar Extravascular/metabolismo , Femenino , Insuficiencia Cardíaca/complicaciones , Insuficiencia Cardíaca/mortalidad , Insuficiencia Cardíaca/terapia , Humanos , Pulmón/metabolismo , Masculino , Persona de Mediana Edad , Admisión del Paciente , Valor Predictivo de las Pruebas , Pronóstico , Estudios Prospectivos , Edema Pulmonar/etiología , Edema Pulmonar/mortalidad , Edema Pulmonar/terapia , Reproducibilidad de los Resultados , Medición de Riesgo , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores de TiempoRESUMEN
RATIONALE: Pulmonary arterial hypertension (PAH) is a vascular remodeling disease with a poor prognosis and limited therapeutic options. Although the mechanisms contributing to vascular remodeling in PAH are still unclear, several features, including hyperproliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMCs), have led to the emergence of the cancer-like concept. The molecular chaperone HSP90 (heat shock protein 90) is directly associated with malignant growth and proliferation under stress conditions. In addition to being highly expressed in the cytosol, HSP90 exists in a subcellular pool compartmentalized in the mitochondria (mtHSP90) of tumor cells, but not in normal cells, where it promotes cell survival. OBJECTIVES: We hypothesized that mtHSP90 in PAH-PASMCs represents a protective mechanism against stress, promoting their proliferation and resistance to apoptosis. METHODS: Expression and localization of HSP90 were analyzed by Western blot, immunofluorescence, and immunogold electron microscopy. In vitro, effects of mtHSP90 inhibition on mitochondrial DNA integrity, bioenergetics, cell proliferation and resistance to apoptosis were assessed. In vivo, the therapeutic potential of Gamitrinib, a mitochondria-targeted HSP90 inhibitor, was tested in fawn-hooded and monocrotaline rats. MEASUREMENTS AND MAIN RESULTS: We demonstrated that, in response to stress, HSP90 preferentially accumulates in PAH-PASMC mitochondria (dual immunostaining, immunoblot, and immunogold electron microscopy) to ensure cell survival by preserving mitochondrial DNA integrity and bioenergetic functions. Whereas cytosolic HSP90 inhibition displays a lack of absolute specificity for PAH-PASMCs, Gamitrinib decreased mitochondrial DNA content and repair capacity and bioenergetic functions, thus repressing PAH-PASMC proliferation (Ki67 labeling) and resistance to apoptosis (Annexin V assay) without affecting control cells. In vivo, Gamitrinib improves PAH in two experimental rat models (monocrotaline and fawn-hooded rat). CONCLUSIONS: Our data show for the first time that accumulation of mtHSP90 is a feature of PAH-PASMCs and a key regulator of mitochondrial homeostasis contributing to vascular remodeling in PAH.
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Antihipertensivos/uso terapéutico , Proteínas HSP90 de Choque Térmico/análisis , Proteínas HSP90 de Choque Térmico/metabolismo , Hipertensión Pulmonar/tratamiento farmacológico , Hipertensión Pulmonar/fisiopatología , Mitocondrias/metabolismo , Remodelación Vascular/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas/efectos de los fármacos , Modelos Animales de Enfermedad , Humanos , Músculo Liso Vascular/efectos de los fármacos , RatasRESUMEN
BACKGROUND: Right ventricular (RV) adaptation to acute and chronic pulmonary hypertensive syndromes is a significant determinant of short- and long-term outcomes. Although remarkable progress has been made in the understanding of RV function and failure since the meeting of the NIH Working Group on Cellular and Molecular Mechanisms of Right Heart Failure in 2005, significant gaps remain at many levels in the understanding of cellular and molecular mechanisms of RV responses to pressure and volume overload, in the validation of diagnostic modalities, and in the development of evidence-based therapies. METHODS: A multidisciplinary working group of 20 international experts from the American Thoracic Society Assemblies on Pulmonary Circulation and Critical Care, as well as external content experts, reviewed the literature, identified important knowledge gaps, and provided recommendations. RESULTS: This document reviews the knowledge in the field of RV failure, identifies and prioritizes the most pertinent research gaps, and provides a prioritized pathway for addressing these preclinical and clinical questions. The group identified knowledge gaps and research opportunities in three major topic areas: 1) optimizing the methodology to assess RV function in acute and chronic conditions in preclinical models, human studies, and clinical trials; 2) analyzing advanced RV hemodynamic parameters at rest and in response to exercise; and 3) deciphering the underlying molecular and pathogenic mechanisms of RV function and failure in diverse pulmonary hypertension syndromes. CONCLUSIONS: This statement provides a roadmap to further advance the state of knowledge, with the ultimate goal of developing RV-targeted therapies for patients with RV failure of any etiology.
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Investigación , Disfunción Ventricular Derecha/diagnóstico , Disfunción Ventricular Derecha/fisiopatología , Función Ventricular Derecha/fisiología , Animales , Humanos , Sociedades Médicas , Estados UnidosRESUMEN
The Division of Lung Diseases of the NHLBI and the Cardiovascular Medical Education and Research Fund held a workshop to discuss how to leverage the anticipated scientific output from the recently launched "Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics" (PVDOMICS) program to develop newer approaches to pulmonary vascular disease. PVDOMICS is a collaborative, protocol-driven network to analyze all patient populations with pulmonary hypertension to define novel pulmonary vascular disease (PVD) phenotypes. Stakeholders, including basic, translational, and clinical investigators; clinicians; patient advocacy organizations; regulatory agencies; and pharmaceutical industry experts, joined to discuss the application of precision medicine to PVD clinical trials. Recommendations were generated for discussion of research priorities in line with NHLBI Strategic Vision Goals that include: (1) A national effort, involving all the stakeholders, should seek to coordinate biosamples and biodata from all funded programs to a web-based repository so that information can be shared and correlated with other research projects. Example programs sponsored by NHLBI include PVDOMICS, Pulmonary Hypertension Breakthrough Initiative, the National Biological Sample and Data Repository for PAH, and the National Precision Medicine Initiative. (2) A task force to develop a master clinical trials protocol for PVD to apply precision medicine principles to future clinical trials. Specific features include: (a) adoption of smaller clinical trials that incorporate biomarker-guided enrichment strategies, using adaptive and innovative statistical designs; and (b) development of newer endpoints that reflect well-defined and clinically meaningful changes. (3) Development of updated and systematic variables in imaging, hemodynamic, cellular, genomic, and metabolic tests that will help precisely identify individual and shared features of PVD and serve as the basis of novel phenotypes for therapeutic interventions.
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Hipertensión Pulmonar/terapia , Medicina de Precisión/métodos , Educación , Humanos , National Heart, Lung, and Blood Institute (U.S.) , Estados UnidosRESUMEN
RATIONALE: Right ventricular (RV) failure is a major cause of morbidity and mortality in pulmonary hypertension, but its mechanism remains unknown. Myocyte enhancer factor 2 (Mef2) has been implicated in RV development, regulating metabolic, contractile, and angiogenic genes. Moreover, Mef2 regulates microRNAs that have emerged as important determinants of cardiac development and disease, but for which the role in RV is still unclear. OBJECTIVE: We hypothesized a critical role of a Mef2-microRNAs axis in RV failure. METHODS AND RESULTS: In a rat pulmonary hypertension model (monocrotaline), we studied RV free wall tissues from rats with normal, compensated, and decompensated RV hypertrophy, carefully defined based on clinically relevant parameters, including RV systolic and end-diastolic pressures, cardiac output, RV size, and morbidity. Mef2c expression was sharply increased in compensating phase of RVH tissues but was lost in decompensation phase of RVH. An unbiased screening of microRNAs in our model resulted to a short microRNA signature of decompensated RV failure, which included the myocardium-specific miR-208, which was progressively downregulated as RV failure progressed, in contrast to what is described in left ventricular failure. With mechanistic in vitro experiments using neonatal and adult RV cardiomyocytes, we showed that miR-208 inhibition, as well as tumor necrosis factor-α, activates the complex mediator of transcription 13/nuclear receptor corepressor 1 axis, which in turn promotes Mef2 inhibition, closing a self-limiting feedback loop, driving the transition from compensating phase of RVH toward decompensation phase of RVH. In our model, serum tumor necrosis factor-α levels progressively increased with time while serum miR-208 levels decreased, mirroring its levels in RV myocardium. CONCLUSIONS: We describe an RV-specific mechanism for heart failure, which could potentially lead to new biomarkers and therapeutic targets.
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Insuficiencia Cardíaca/metabolismo , Hipertensión Pulmonar/metabolismo , Factores de Transcripción MEF2/biosíntesis , MicroARNs/biosíntesis , Función Ventricular Derecha/fisiología , Animales , Células Cultivadas , Insuficiencia Cardíaca/patología , Hipertensión Pulmonar/patología , Masculino , Miocitos Cardíacos/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-DawleyRESUMEN
The eukaryote's mitochondrial network is perhaps the cell's most sophisticated and dynamic responsive sensing system. Integrating metabolic, oxygen, or danger signals with inputs from other organelles, as well as local and systemic signals, mitochondria have a profound impact on vascular function in both health and disease. This review highlights recently discovered aspects of mitochondrial function (oxygen sensing, inflammation, autophagy, and apoptosis) and discusses their role in diseases of both systemic and pulmonary vessels. We also emphasize the role of mitochondria as therapeutic targets for vascular disease. We highlight the intriguing similarities of mitochondria-driven molecular mechanisms in terms of both pathogenesis and therapies in very diverse diseases, such as atherosclerosis, pulmonary hypertension, and cancer, to support the foundation of a new field in medicine: mitochondrial medicine.
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Enfermedades Cardiovasculares/fisiopatología , Fenómenos Fisiológicos Cardiovasculares , Mitocondrias/fisiología , Animales , Homeostasis/fisiología , Humanos , Hipertensión/fisiopatología , Oxígeno/metabolismoRESUMEN
BACKGROUND: Right ventricular (RV) failure is the most important factor of both morbidity and mortality in pulmonary arterial hypertension (PAH). However, the underlying mechanisms resulting in the failed RV in PAH remain unknown. There is growing evidence that angiogenesis and microRNAs are involved in PAH-associated RV failure. We hypothesized that microRNA-126 (miR-126) downregulation decreases microvessel density and promotes the transition from a compensated to a decompensated RV in PAH. METHODS AND RESULTS: We studied RV free wall tissues from humans with normal RV (n=17), those with compensated RV hypertrophy (n=8), and patients with PAH with decompensated RV failure (n=14). Compared with RV tissues from patients with compensated RV hypertrophy, patients with decompensated RV failure had decreased miR-126 expression (quantitative reverse transcription-polymerase chain reaction; P<0.01) and capillary density (CD31(+) immunofluorescence; P<0.001), whereas left ventricular tissues were not affected. miR-126 downregulation was associated with increased Sprouty-related EVH1 domain-containing protein 1 (SPRED-1), leading to decreased activation of RAF (phosphorylated RAF/RAF) and mitogen-activated protein kinase (MAPK); (phosphorylated MAPK/MAPK), thus inhibiting the vascular endothelial growth factor pathway. In vitro, Matrigel assay showed that miR-126 upregulation increased angiogenesis of primary cultured endothelial cells from patients with decompensated RV failure. Furthermore, in vivo miR-126 upregulation (mimic intravenous injection) improved cardiac vascular density and function of monocrotaline-induced PAH animals. CONCLUSIONS: RV failure in PAH is associated with a specific molecular signature within the RV, contributing to a decrease in RV vascular density and promoting the progression to RV failure. More importantly, miR-126 upregulation in the RV improves microvessel density and RV function in experimental PAH.
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Regulación hacia Abajo/fisiología , Insuficiencia Cardíaca/metabolismo , Hipertensión Pulmonar/metabolismo , MicroARNs/metabolismo , Disfunción Ventricular Derecha/metabolismo , Adulto , Anciano , Animales , Células Cultivadas , Femenino , Insuficiencia Cardíaca/diagnóstico , Humanos , Hipertensión Pulmonar/diagnóstico , Masculino , Persona de Mediana Edad , Ratas , Ratas Sprague-Dawley , Disfunción Ventricular Derecha/diagnósticoRESUMEN
Numerous molecular abnormalities have been described in pulmonary arterial hypertension (PAH), complicating the translation of candidate therapies to patients because, typically, 1 treatment addresses only 1 abnormality. The realization that in addition to pulmonary artery vascular cells, other tissues and cells are involved in the syndrome of PAH (eg, immune cells, right ventricular cardiomyocytes, skeletal muscle) further complicates the identification of optimal therapeutic targets. Here, we describe a metabolic theory that proposes that many apparently unrelated molecular abnormalities in PAH do have a common denominator; they either cause or promote a mitochondrial suppression (inhibition of glucose oxidation) in pulmonary vascular cells; in turn, the signaling downstream from this mitochondrial suppression can also explain numerous molecular events previously not connected. This integration of signals upstream and downstream of mitochondria has similarities to cancer and can explain many features of the PAH vascular phenotype, including proliferation and apoptosis resistance. This suppression of glucose oxidation (with secondary upregulation of glycolysis) also underlies the abnormalities in extrapulmonary tissues, suggesting a global metabolic disturbance. The metabolic theory places mitochondria at the center stage for our understanding of PAH pathogenesis and for the development of novel diagnostic and therapeutic tools. Current PAH therapies are each addressing 1 abnormality (eg, upregulation of endothelin-1) and were not developed specifically for PAH but for systemic vascular diseases. Compared with the available therapies, mitochondria-targeting therapies have the advantage of addressing multiple molecular abnormalities simultaneously (thus being potentially more effective) and achieving higher specificity because they address PAH-specific biology.
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Hipertensión Pulmonar/etiología , Hipertensión Pulmonar/metabolismo , Mitocondrias/fisiología , Animales , Apoptosis , Estrés del Retículo Endoplásmico , Hipertensión Pulmonar Primaria Familiar , Glucosa/metabolismo , Ventrículos Cardíacos/metabolismo , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/fisiología , Canales Iónicos/fisiología , Proteínas Mitocondriales/fisiología , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , Miocitos del Músculo Liso/metabolismo , Miocitos del Músculo Liso/patología , Arteria Pulmonar/metabolismo , Arteria Pulmonar/patología , Transducción de Señal , Proteína Desacopladora 2RESUMEN
BACKGROUND: Pulmonary arterial hypertension (PAH) is associated with sustained inflammation known to promote DNA damage. Despite these unfavorable environmental conditions, PAH pulmonary arterial smooth muscle cells (PASMCs) exhibit, in contrast to healthy PASMCs, a pro-proliferative and anti-apoptotic phenotype, sustained in time by the activation of miR-204, nuclear factor of activated T cells, and hypoxia-inducible factor 1-α. We hypothesized that PAH-PASMCs have increased the activation of poly(ADP-ribose) polymerase-1 (PARP-1), a critical enzyme implicated in DNA repair, allowing proliferation despite the presence of DNA-damaging insults, eventually leading to PAH. METHODS AND RESULTS: Human PAH distal pulmonary arteries and cultured PAH-PASMCs exhibit increased DNA damage markers (53BP1 and γ-H2AX) and an overexpression of PARP-1 (immunoblot and activity assay), in comparison with healthy tissues/cells. Healthy PASMCs treated with a clinically relevant dose of tumor necrosis factor-α harbored a similar phenotype, suggesting that inflammation induces DNA damage and PARP-1 activation in PAH. We also showed that PARP-1 activation accounts for miR-204 downregulation (quantitative reverse transcription polymerase chain reaction) and the subsequent activation of the transcription factors nuclear factor of activated T cells and hypoxia-inducible factor 1-α in PAH-PASMCs, previously shown to be critical for PAH in several models. These effects resulted in PASMC proliferation (Ki67, proliferating cell nuclear antigen, and WST1 assays) and resistance to apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling and Annexin V assays). In vivo, the clinically available PARP inhibitor ABT-888 reversed PAH in 2 experimental rat models (Sugen/hypoxia and monocrotaline). CONCLUSIONS: These results show for the first time that the DNA damage/PARP-1 signaling pathway is important for PAH development and provide a new therapeutic target for this deadly disease with high translational potential.
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Daño del ADN/fisiología , Hipertensión Pulmonar/genética , Hipertensión Pulmonar/metabolismo , Poli(ADP-Ribosa) Polimerasas/genética , Transducción de Señal/fisiología , Adulto , Anciano , Animales , Apoptosis/fisiología , Bencimidazoles/farmacología , Proliferación Celular , Células Cultivadas , Modelos Animales de Enfermedad , Hipertensión Pulmonar Primaria Familiar , Femenino , Humanos , Hipertensión Pulmonar/patología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Masculino , MicroARNs/metabolismo , Persona de Mediana Edad , Monocrotalina/farmacología , Factores de Transcripción NFATC/metabolismo , Poli(ADP-Ribosa) Polimerasa-1 , Poli(ADP-Ribosa) Polimerasas/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Purpose Preclinical evidence suggests dichloroacetate (DCA) can reverse the Warburg effect and inhibit growth in cancer models. This phase 1 study was undertaken to assess the safety, recommended phase 2 dose (RP2D), and pharmacokinetic (PK) profile of oral DCA in patients with advanced solid tumors. Patients and Methods Twenty-four patients with advanced solid malignancies were enrolled using a standard 3 + 3 protocol at a starting dose of 6.25 mg/kg twice daily (BID). Treatment on 28 days cycles was continued until progression, toxicity, or consent withdrawal. PK samples were collected on days 1 and 15 of cycle 1, and day 1 of subsequent cycles. PET imaging ((18) F-FDG uptake) was investigated as a potential biomarker of response. Results Twenty-three evaluable patients were treated with DCA at two doses: 6.25 mg/kg and 12.5 mg/kg BID (median of 2 cycles each). No DLTs occurred in the 6.25 mg/kg BID cohort so the dose was escalated. Three of seven patients had DLTs (fatigue, vomiting, diarrhea) at 12.5 mg/kg BID. Thirteen additional patients were treated at 6.25 mg/kg BID. Most toxicities were grade 1-2 with the most common being fatigue, neuropathy and nausea. No responses were observed and eight patients had stable disease. The DCA PK profile in cancer patients was consistent with previously published data. There was high variability in PK values and neuropathy among patients. Progressive increase in DCA trough levels and a trend towards decreased (18) F-FDG uptake with length of DCA therapy was observed. Conclusions The RP2D of oral DCA is 6.25 mg/kg BID. Toxicities will require careful monitoring in future trials.
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Ácido Dicloroacético/uso terapéutico , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Adulto , Anciano , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Estudios de Cohortes , Ácido Dicloroacético/efectos adversos , Ácido Dicloroacético/farmacocinética , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias/metabolismoRESUMEN
RATIONALE: Mitochondrial signaling regulates both the acute and the chronic response of the pulmonary circulation to hypoxia, and suppressed mitochondrial glucose oxidation contributes to the apoptosis-resistance and proliferative diathesis in the vascular remodeling in pulmonary hypertension. Hypoxia directly inhibits glucose oxidation, whereas endoplasmic reticulum (ER)-stress can indirectly inhibit glucose oxidation by decreasing mitochondrial calcium (Ca²âºm levels). Both hypoxia and ER stress promote proliferative pulmonary vascular remodeling. Uncoupling protein 2 (UCP2) has been shown to conduct calcium from the ER to mitochondria and suppress mitochondrial function. OBJECTIVE: We hypothesized that UCP2 deficiency reduces Ca²âºm in pulmonary artery smooth muscle cells (PASMCs), mimicking the effects of hypoxia and ER stress on mitochondria in vitro and in vivo, promoting normoxic hypoxia inducible factor-1α activation and pulmonary hypertension. METHODS AND RESULTS: Ucp2 knockout (KO)-PASMCs had lower mitochondrial calcium than Ucp2 wildtype (WT)-PASMCs at baseline and during histamine-stimulated ER-Ca²âº release. Normoxic Ucp2KO-PASMCs had mitochondrial hyperpolarization, lower Ca²âº-sensitive mitochondrial enzyme activity, reduced levels of mitochondrial reactive oxygen species and Krebs' cycle intermediates, and increased resistance to apoptosis, mimicking the hypoxia-induced changes in Ucp2WT-PASMC. Ucp2KO mice spontaneously developed pulmonary vascular remodeling and pulmonary hypertension and exhibited a pseudohypoxic state with pulmonary vascular and systemic hypoxia inducible factor-1α activation (increased hematocrit), not exacerbated further by chronic hypoxia. CONCLUSIONS: This first description of the role of UCP2 in oxygen sensing and in pulmonary hypertension vascular remodeling may open a new window in biomarker and therapeutic strategies.
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Estrés del Retículo Endoplásmico/fisiología , Hipertensión Pulmonar/metabolismo , Hipoxia/metabolismo , Canales Iónicos/deficiencia , Mitocondrias/metabolismo , Proteínas Mitocondriales/deficiencia , Arteria Pulmonar/metabolismo , Animales , Células Cultivadas , Hipertensión Pulmonar/patología , Hipoxia/patología , Ratones , Ratones Noqueados , Imitación Molecular/fisiología , Miocitos del Músculo Liso/metabolismo , Miocitos del Músculo Liso/patología , Arteria Pulmonar/patología , Distribución Aleatoria , Proteína Desacopladora 2RESUMEN
RATIONALE: Right ventricular (RV) function is the most important determinant of morbidity and mortality in pulmonary arterial hypertension (PAH). Endothelin (ET)-1 receptor antagonists (ERAs) are approved therapies for PAH. It is not known whether ERAs have effects on the RV, in addition to their vasodilating/antiproliferative effects in pulmonary arteries. OBJECTIVE: We hypothesized that the ET axis is upregulated in RV hypertrophy (RVH) and that ERAs have direct effects on the RV myocardium. METHODS AND RESULTS: RV myocardial samples from 34 patients with RVH were compared with 16 nonhypertrophied RV samples, and from rats with normal RV versus RVH attributable to PAH. Confocal immunohistochemistry showed that RVH myocardial ET type A (but not type B) receptor and ET-1 protein levels were increased compared with the nonhypertrophied RVs and positively correlated with the degree of RVH (RV thickness/body surface area; r(2)=0.838 and r(2)=0.818, respectively; P<0.01). These results were recapitulated in the rat model. In modified Langendorff perfusions, ERAs (BQ-123 and bosentan 10(-7,-6,-5) mol/L) decreased contractility in the hypertrophied, but not normal RV, in a dose-dependent manner (P<0.01). CONCLUSIONS: Patients and rats with PAH have an upregulation of the myocardial ET axis in RVH. This might be a compensatory mechanism to preserve RV contractility, as the afterload increases. ERAs use might potentially worsen RV function, and this could explain some of the peripheral edema noted clinically with these agents. Further studies are required to evaluate the effects of ERAs on the RV in patients with RVH and PAH.
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Endotelina-1/biosíntesis , Endotelinas/biosíntesis , Hipertrofia Ventricular Derecha/metabolismo , Receptor de Endotelina A/biosíntesis , Regulación hacia Arriba/fisiología , Función Ventricular Derecha , Adolescente , Adulto , Animales , Niño , Preescolar , Endotelinas/fisiología , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Ratas , Receptor de Endotelina A/fisiología , Función Ventricular Derecha/fisiología , Adulto JovenRESUMEN
The unique metabolic profile of cancer (aerobic glycolysis) might confer apoptosis resistance and be therapeutically targeted. Compared to normal cells, several human cancers have high mitochondrial membrane potential (DeltaPsim) and low expression of the K+ channel Kv1.5, both contributing to apoptosis resistance. Dichloroacetate (DCA) inhibits mitochondrial pyruvate dehydrogenase kinase (PDK), shifts metabolism from glycolysis to glucose oxidation, decreases DeltaPsim, increases mitochondrial H2O2, and activates Kv channels in all cancer, but not normal, cells; DCA upregulates Kv1.5 by an NFAT1-dependent mechanism. DCA induces apoptosis, decreases proliferation, and inhibits tumor growth, without apparent toxicity. Molecular inhibition of PDK2 by siRNA mimics DCA. The mitochondria-NFAT-Kv axis and PDK are important therapeutic targets in cancer; the orally available DCA is a promising selective anticancer agent.
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Apoptosis/fisiología , Mitocondrias/metabolismo , Neoplasias/metabolismo , Canales de Potasio/metabolismo , Animales , Línea Celular Tumoral , Ácido Dicloroacético/farmacología , Humanos , Immunoblotting , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Potencial de la Membrana Mitocondrial/fisiología , Microscopía Confocal , Mitocondrias/efectos de los fármacos , Factores de Transcripción NFATC/metabolismo , Técnicas de Placa-Clamp , Canales de Potasio/efectos de los fármacos , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas , Piruvato Deshidrogenasa Quinasa Acetil-Transferidora , Ratas , Ratas Desnudas , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
BACKGROUND: Evidence suggestive of endoplasmic reticulum (ER) stress in the pulmonary arteries of patients with pulmonary arterial hypertension has been described for decades but has never been therapeutically targeted. ER stress is a feature of many conditions associated with pulmonary arterial hypertension like hypoxia, inflammation, or loss-of-function mutations. ER stress signaling in the pulmonary circulation involves the activation of activating transcription factor 6, which, via induction of the reticulin protein Nogo, can lead to the disruption of the functional ER-mitochondria unit and the increasingly recognized cancer-like metabolic shift in pulmonary arterial hypertension that promotes proliferation and apoptosis resistance in the pulmonary artery wall. We hypothesized that chemical chaperones known to suppress ER stress signaling, like 4-phenylbutyrate (PBA) or tauroursodeoxycholic acid, will inhibit the disruption of the ER-mitochondrial unit and prevent/reverse pulmonary arterial hypertension. METHODS AND RESULTS: PBA in the drinking water both prevented and reversed chronic hypoxia-induced pulmonary hypertension in mice, decreasing pulmonary vascular resistance, pulmonary artery remodeling, and right ventricular hypertrophy and improving functional capacity without affecting systemic hemodynamics. These results were replicated in the monocrotaline rat model. PBA and tauroursodeoxycholic acid improved ER stress indexes in vivo and in vitro, decreased activating transcription factor 6 activation (cleavage, nuclear localization, luciferase, and downstream target expression), and inhibited the hypoxia-induced decrease in mitochondrial calcium and mitochondrial function. In addition, these chemical chaperones suppressed proliferation and induced apoptosis in pulmonary artery smooth muscle cells in vitro and in vivo. CONCLUSIONS: Attenuating ER stress with clinically used chemical chaperones may be a novel therapeutic strategy in pulmonary hypertension with high translational potential.