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OBJECTIVE: Fluid shear stress (FSS) is known to mediate multiple phenotypic changes in the endothelium. Laminar FSS (undisturbed flow) is known to promote endothelial alignment to flow, which is key to stabilizing the endothelium and rendering it resistant to atherosclerosis and thrombosis. The molecular pathways responsible for endothelial responses to FSS are only partially understood. In this study, we determine the role of PGC1α (peroxisome proliferator gamma coactivator-1α)-TERT (telomerase reverse transcriptase)-HMOX1 (heme oxygenase-1) during shear stress in vitro and in vivo. Approach and Results: Here, we have identified PGC1α as a flow-responsive gene required for endothelial flow alignment in vitro and in vivo. Compared with oscillatory FSS (disturbed flow) or static conditions, laminar FSS (undisturbed flow) showed increased PGC1α expression and its transcriptional coactivation. PGC1α was required for laminar FSS-induced expression of TERT in vitro and in vivo via its association with ERRα(estrogen-related receptor alpha) and KLF (Kruppel-like factor)-4 on the TERT promoter. We found that TERT inhibition attenuated endothelial flow alignment, elongation, and nuclear polarization in response to laminar FSS in vitro and in vivo. Among the flow-responsive genes sensitive to TERT status, HMOX1 was required for endothelial alignment to laminar FSS. CONCLUSIONS: These data suggest an important role for a PGC1α-TERT-HMOX1 axis in the endothelial stabilization response to laminar FSS.
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Células Endoteliales/enzimología , Hemo-Oxigenasa 1/metabolismo , Mecanotransducción Celular , Proteínas de la Membrana/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Telomerasa/metabolismo , Animales , Células Cultivadas , Células Endoteliales/patología , Transición Epitelial-Mesenquimal , Femenino , Regulación Enzimológica de la Expresión Génica , Hemo-Oxigenasa 1/genética , Células Endoteliales de la Vena Umbilical Humana/enzimología , Células Endoteliales de la Vena Umbilical Humana/patología , Humanos , Masculino , Proteínas de la Membrana/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Flujo Sanguíneo Regional , Estrés Mecánico , Telomerasa/genéticaRESUMEN
BACKGROUND AND AIMS: Oxidative stress plays a key role in the development of metabolic complications associated with obesity, including insulin resistance and the most common chronic liver disease worldwide, nonalcoholic fatty liver disease. We have recently discovered that the microRNA miR-144 regulates protein levels of the master mediator of the antioxidant response, nuclear factor erythroid 2-related factor 2 (NRF2). On miR-144 silencing, the expression of NRF2 target genes was significantly upregulated, suggesting that miR-144 controls NRF2 at the level of both protein expression and activity. Here we explored a mechanism whereby hepatic miR-144 inhibited NRF2 activity upon obesity via the regulation of the tricarboxylic acid (TCA) metabolite, fumarate, a potent activator of NRF2. METHODS: We performed transcriptomic analysis in liver macrophages (LMs) of obese mice and identified the immuno-responsive gene 1 (Irg1) as a target of miR-144. IRG1 catalyzes the production of a TCA derivative, itaconate, an inhibitor of succinate dehydrogenase (SDH). TCA enzyme activities and kinetics were analyzed after miR-144 silencing in obese mice and human liver organoids using single-cell activity assays in situ and molecular dynamic simulations. RESULTS: Increased levels of miR-144 in obesity were associated with reduced expression of Irg1, which was restored on miR-144 silencing in vitro and in vivo. Furthermore, miR-144 overexpression reduces Irg1 expression and the production of itaconate in vitro. In alignment with the reduction in IRG1 levels and itaconate production, we observed an upregulation of SDH activity during obesity. Surprisingly, however, fumarate hydratase (FH) activity was also upregulated in obese livers, leading to the depletion of its substrate fumarate. miR-144 silencing selectively reduced the activities of both SDH and FH resulting in the accumulation of their related substrates succinate and fumarate. Moreover, molecular dynamics analyses revealed the potential role of itaconate as a competitive inhibitor of not only SDH but also FH. Combined, these results demonstrate that silencing of miR-144 inhibits the activity of NRF2 through decreased fumarate production in obesity. CONCLUSIONS: Herein we unravel a novel mechanism whereby miR-144 inhibits NRF2 activity through the consumption of fumarate by activation of FH. Our study demonstrates that hepatic miR-144 triggers a hyperactive FH in the TCA cycle leading to an impaired antioxidant response in obesity.
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Hígado Graso/enzimología , Fumarato Hidratasa/metabolismo , Resistencia a la Insulina , Hígado/enzimología , Macrófagos/enzimología , MicroARNs/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Obesidad/enzimología , Animales , Carboxiliasas/genética , Carboxiliasas/metabolismo , Ciclo del Ácido Cítrico , Modelos Animales de Enfermedad , Hígado Graso/genética , Fumarato Hidratasa/genética , Fumaratos/metabolismo , Humanos , Hidroliasas/genética , Hidroliasas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , MicroARNs/genética , Factor 2 Relacionado con NF-E2/genética , Obesidad/genética , Estrés Oxidativo , Células RAW 264.7 , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Succinatos/metabolismoRESUMEN
Exercise mitigates chronic diseases such as diabetes, cardiovascular diseases, and obesity; however, the molecular mechanisms governing protection from these diseases are not completely understood. Here we demonstrate that exercise rescues metabolically compromised high fat diet (HFD) fed mice, and reprograms subcutaneous white adipose tissue (scWAT). Using transcriptomic profiling, scWAT was analyzed for HFD gene expression changes that were rescued by exercise. Gene networks involved in vascularization were identified as prominent targets of exercise, which led us to investigate the vasculature architecture and endothelial phenotype. Vascular density in scWAT was found to be compromised in HFD, and exercise rescued this defect. Similarly, angiogenic capacity as measured by ex vivo capillary sprouting was significantly promoted with exercise. Together, these data demonstrate that exercise enhances scWAT vascularization and functional capacity for angiogenesis, and can prevent the detrimental effects of HFD. The improvement in these indices correlates with improvement of whole-body metabolism, suggesting that scWAT vascularization may be a potential therapeutic target for metabolic disease.
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Neovascularización Fisiológica/genética , Condicionamiento Físico Animal , Transducción de Señal/genética , Grasa Subcutánea/irrigación sanguínea , Adaptación Fisiológica , Animales , Dieta Alta en Grasa , Glucosa/metabolismo , Homeostasis , Masculino , Ratones Endogámicos C57BL , Transcriptoma/genéticaRESUMEN
Altered energy balance and insulin resistance are important characteristics of aging. Skeletal muscle is a major site of glucose disposal, and the role of aging-associated inflammation in skeletal muscle insulin resistance remains unclear. To investigate, we examined glucose metabolism in 18-mo-old transgenic mice with muscle-specific overexpression of IL-10 (MIL10) and in wild-type mice during hyperinsulinemic-euglycemic clamping. Despite similar fat mass and energy balance, MIL10 mice were protected from aging-associated insulin resistance with significant increases in glucose infusion rates, whole-body glucose turnover, and skeletal muscle glucose uptake (â¼60%; P < 0.05), as compared to age-matched WT mice. This protective effect was associated with decreased muscle inflammation, but no changes in adipose tissue inflammation in aging MIL10 mice. These results demonstrate the importance of skeletal muscle inflammation in aging-mediated insulin resistance, and our findings further implicate a potential therapeutic role of anti-inflammatory cytokine in the treatment of aging-mediated insulin resistance.-Dagdeviren, S., Jung, D. Y., Friedline, R. H., Noh, H. L., Kim, J. H., Patel, P. R., Tsitsilianos, N., Inashima, K., Tran, D. A., Hu, X., Loubato, M. M., Craige, S. M., Kwon, J. Y., Lee, K. W., Kim, J. K. IL-10 prevents aging-associated inflammation and insulin resistance in skeletal muscle.
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Envejecimiento/fisiología , Inflamación/metabolismo , Resistencia a la Insulina/fisiología , Interleucina-10/metabolismo , Músculo Esquelético/metabolismo , Animales , Forma MM de la Creatina-Quinasa , Metabolismo Energético , Interleucina-10/genética , Masculino , Ratones , Ratones TransgénicosRESUMEN
Mixed lineage kinases, or MLKs, are members of the MAP kinase kinase kinase (MAP3K) family, which were originally identified among the activators of the major stress-dependent mitogen activated protein kinases (MAPKs), JNK and p38. During stress, the activation of JNK and p38 kinases targets several essential downstream substrates that react in a specific manner to the unique stressor and thus determine the fate of the cell in response to a particular challenge. Recently, the MLK family was identified as a specific modulator of JNK and p38 signaling in metabolic syndrome. Moreover, the MLK family of kinases appears to be involved in a very wide spectrum of disorders. This review discusses the newly identified functions of MLKs in multiple diseases including metabolic disorders, inflammation, cancer, and neurological diseases.
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Inflamación/enzimología , Quinasas Quinasa Quinasa PAM/metabolismo , Enfermedades Metabólicas/enzimología , Animales , Enfermedades Cardiovasculares/enzimología , Citocinas/biosíntesis , Humanos , Resistencia a la Insulina/fisiología , Hepatopatías/enzimología , Quinasas Quinasa Quinasa PAM/química , Sistema de Señalización de MAP Quinasas , Síndrome Metabólico/enzimología , Neoplasias/enzimología , Enfermedades del Sistema Nervioso/enzimología , Obesidad/enzimología , Estrés FisiológicoRESUMEN
Metabolic stress sensors like AMP-activated protein kinase (AMPK) are known to confer stress adaptation and promote longevity in lower organisms. This study demonstrates that activating the metabolic stress sensor AMP-activated protein kinase (AMPK) in endothelial cells helps maintain normal cellular function by promoting mitochondrial biogenesis and stress adaptation. To better define the mechanisms whereby AMPK promotes endothelial stress resistance, we used 5-aminoimidazole-4-carboxamide riboside (AICAR) to chronically activate AMPK and observed stimulation of mitochondrial biogenesis in wild type mouse endothelium, but not in endothelium from endothelial nitric oxide synthase knockout (eNOS-null) mice. Interestingly, AICAR-enhanced mitochondrial biogenesis was blocked by pretreatment with the mammalian target of rapamycin complex 1 (mTORC1) inhibitor, rapamycin. Further, AICAR stimulated mTORC1 as determined by phosphorylation of its known downstream effectors in wild type, but not eNOS-null, endothelial cells. Together these data indicate that eNOS is needed to couple AMPK activation to mTORC1 and thus promote mitochondrial biogenesis and stress adaptation in the endothelium. These data suggest a novel mechanism for mTORC1 activation that is significant for investigations in vascular dysfunction.
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Proteínas Quinasas Activadas por AMP/metabolismo , Células Endoteliales/metabolismo , Mitocondrias/metabolismo , Adaptación Fisiológica , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacología , Animales , Calcimicina/farmacología , Células Cultivadas , Endotelio Vascular/metabolismo , Activadores de Enzimas/farmacología , Humanos , Peróxido de Hidrógeno/farmacología , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones Noqueados , Óxido Nítrico Sintasa de Tipo III/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Biogénesis de Organelos , Estrés Oxidativo , Ratas , Ribonucleótidos/farmacología , Transducción de Señal , Sirolimus/farmacologíaRESUMEN
Endothelial function is largely dictated by its ability to rapidly sense environmental cues and adapt to these stimuli through changes in vascular tone, inflammation/immune recruitment, and angiogenesis. When any one of these abilities is compromised, the endothelium becomes dysfunctional, which ultimately leads to disease. Reactive oxygen species (ROS) have been established at the forefront of endothelial dysfunction; however, more careful examination has demonstrated that ROS are fundamental to each of the sensing/signaling roles of the endothelium. The purpose of this review is to document endothelial ROS production in both disease and physiological adaptation. Through understanding new endothelial signaling paradigms, we will gain insight into more targeted therapeutic strategies for vascular diseases.
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Adaptación Fisiológica , Enfermedades Cardiovasculares/fisiopatología , Endotelio Vascular/fisiología , Especies Reactivas de Oxígeno/metabolismo , Acetilcolina/farmacología , Animales , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiopatología , Factores Relajantes Endotelio-Dependientes/fisiología , Humanos , Hipoxia/fisiopatología , NADPH Oxidasas/fisiología , Neovascularización Fisiológica , Óxido Nítrico/fisiología , Óxido Nítrico Sintasa de Tipo III/fisiología , Especies Reactivas de Oxígeno/inmunología , Transducción de Señal/fisiología , Resistencia Vascular/fisiología , Vasculitis/inmunología , Vasculitis/fisiopatología , Vasodilatación/fisiologíaRESUMEN
Bone marrow stromal cells (BMSCs) play a significant role in bone metabolism as they can differentiate into osteoblasts, bone marrow adipocytes (BMAds), and chondrocytes. BMSCs chronically exposed to nutrient overload undergo adipogenic programming, resulting in bone marrow adipose tissue (BMAT) formation. BMAT is a fat depot transcriptionally, metabolically, and morphologically distinct from peripheral adipose depots. Reactive oxygen species (ROS) are elevated in obesity and serve as important signals directing BMSC fate. ROS produced by the NADPH oxidase (NOX) family of enzymes, such as NOX4, may be responsible for driving BMSC adipogenesis at the expense of osteogenic differentiation. The dual nature of ROS as both cellular signaling mediators and contributors to oxidative stress complicates their effects on bone metabolism. This review discusses the complex interplay between ROS and BMSC differentiation in the context of metabolic bone diseases.Special attention is paid to the role of NOX4-ROS in regulating cellular processes within the bone marrow microenvironment and potential target in metabolic bone diseases.
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Alzheimer's disease (AD) develops along a continuum that spans years prior to diagnosis. Decreased muscle function and mitochondrial respiration occur years earlier in those that develop AD; however, it is unknown what causes these peripheral phenotypes in a disease of the brain. Exercise promotes muscle, mitochondria, and cognitive health and is proposed to be a potential therapeutic for AD, but no study has investigated how skeletal muscle adapts to exercise training in an AD-like context. Utilizing 5xFAD mice, an AD model that develops ad-like pathology and cognitive impairments around 6 mo of age, we examined in vivo neuromuscular function and exercise adapations (mitochondrial respiration and RNA sequencing) before the manifestation of overt cognitive impairment. We found 5xFAD mice develop neuromuscular dysfunction beginning as early as 4 mo of age, characterized by impaired nerve-stimulated muscle torque production and compound nerve action potential of the sciatic nerve. Furthermore, skeletal muscle in 5xFAD mice had altered, sex-dependent, adaptive responses (mitochondrial respiration and gene expression) to exercise training in the absence of overt cognitive impairment. Changes in peripheral systems, specifically neural communication to skeletal muscle, may be harbingers for AD and have implications for lifestyle interventions, like exercise, in AD.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Ratones , Animales , Enfermedad de Alzheimer/genética , Ratones Transgénicos , Encéfalo/metabolismo , Disfunción Cognitiva/etiología , Mitocondrias/metabolismoRESUMEN
UNLABELLED: BACKGROUND- Reactive oxygen species serve signaling functions in the vasculature, and hypoxia has been associated with increased reactive oxygen species production. NADPH oxidase 4 (Nox4) is a reactive oxygen species-producing enzyme that is highly expressed in the endothelium, yet its specific role is unknown. We sought to determine the role of Nox4 in the endothelial response to hypoxia. METHODS AND RESULTS: Hypoxia induced Nox4 expression both in vitro and in vivo and overexpression of Nox4 was sufficient to promote endothelial proliferation, migration, and tube formation. To determine the in vivo relevance of our observations, we generated transgenic mice with endothelial-specific Nox4 overexpression using the vascular endothelial cadherin promoter (VECad-Nox4 mice). In vivo, the VECad-Nox4 mice had accelerated recovery from hindlimb ischemia and enhanced aortic capillary sprouting. Because endothelial nitric oxide synthase (eNOS) is involved in endothelial angiogenic responses and eNOS is activated by reactive oxygen species, we probed the effect of Nox4 on eNOS. In cultured endothelial cells overexpressing Nox4, we observed a significant increase in eNOS protein expression and activity. To causally address the link between eNOS and Nox4, we crossed our transgenic Nox4 mice with eNOS(-/-) mice. Aortas from these mice did not demonstrate enhanced aortic sprouting, and VECad-Nox4 mice on the eNOS(-/-) background did not demonstrate enhanced recovery from hindlimb ischemia. CONCLUSIONS: Collectively, we demonstrate that augmented endothelial Nox4 expression promotes angiogenesis and recovery from hypoxia in an eNOS-dependent manner.
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NADPH Oxidasas/fisiología , Neovascularización Fisiológica/fisiología , Animales , Bovinos , Hipoxia de la Célula/genética , Células Cultivadas/enzimología , GMP Cíclico/metabolismo , Células Endoteliales/enzimología , Inducción Enzimática , Terapia Genética , Vectores Genéticos/administración & dosificación , Vectores Genéticos/uso terapéutico , Miembro Posterior/irrigación sanguínea , Humanos , Isquemia/terapia , Ratones , Ratones Transgénicos , NADPH Oxidasa 4 , NADPH Oxidasas/biosíntesis , NADPH Oxidasas/genética , Óxido Nítrico Sintasa de Tipo III/deficiencia , Óxido Nítrico Sintasa de Tipo III/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Óxido Nítrico Sintasa de Tipo III/fisiología , Interferencia de ARN , ARN Interferente Pequeño/farmacología , Especies Reactivas de Oxígeno , Proteínas Recombinantes de Fusión/fisiologíaRESUMEN
The energetic requirements of skeletal muscle to sustain movement, as during exercise, is met largely by mitochondria, which form an intricate, interconnected reticulum. Maintenance of a healthy mitochondrial reticulum is essential for skeletal muscle function, suggesting quality control pathways are spatially governed. Mitophagy, the process by which damaged and/or dysfunctional regions of the mitochondrial reticulum are removed and degraded, has emerged as an integral part of the molecular response to exercise. Upregulation of mitophagy in response to acute exercise is directly connected to energetic sensing mechanisms through AMPK. In this review, we discuss the connection of mitophagy to muscle energetics and how AMPK may spatially control mitophagy through multiple potential means.
RESUMEN
OBJECTIVE: The immediate signals that couple exercise to metabolic adaptations are incompletely understood. Nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) produces reactive oxygen species (ROS) and plays a significant role in metabolic and vascular adaptation during stress conditions. Our objective was to determine the role of Nox4 in exercise-induced skeletal muscle metabolism. METHODS: Mice were subjected to acute exercise to assess their immediate responses. mRNA and protein expression responses to Nox4 and hydrogen peroxide (H2O2) were measured by qPCR and immunoblotting. Functional metabolic flux was measured via ex vivo fatty acid and glucose oxidation assays using 14C-labeled palmitate and glucose, respectively. A chronic exercise regimen was also utilized and the time to exhaustion along with key markers of exercise adaptation (skeletal muscle citrate synthase and beta-hydroxyacyl-coA-dehydrogenase activity) were measured. Endothelial-specific Nox4-deficient mice were then subjected to the same acute exercise regimen and their subsequent substrate oxidation was measured. RESULTS: We identified key exercise-responsive metabolic genes that depend on H2O2 and Nox4 using catalase and Nox4-deficient mice. Nox4 was required for the expression of uncoupling protein 3 (Ucp3), hexokinase 2 (Hk2), and pyruvate dehydrogenase kinase 4 (Pdk4), but not the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc-1α). Global Nox4 deletion resulted in decreased UCP3 protein expression and impaired glucose and fatty acid oxidization in response to acute exercise. Furthermore, Nox4-deficient mice demonstrated impaired adaptation to chronic exercise as measured by the time to exhaustion and activity of skeletal muscle citrate synthase and beta-hydroxyacyl-coA-dehydrogenase. Importantly, mice deficient in endothelial-Nox4 similarly demonstrated attenuated glucose and fatty acid oxidation following acute exercise. CONCLUSIONS: We report that H2O2 and Nox4 promote immediate responses to exercise in skeletal muscle. Glucose and fatty acid oxidation were blunted in the Nox4-deficient mice post-exercise, potentially through regulation of UCP3 expression. Our data demonstrate that endothelial-Nox4 is required for glucose and fatty acid oxidation, suggesting inter-tissue cross-talk between the endothelium and skeletal muscle in response to exercise.
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Músculo Esquelético/metabolismo , NADPH Oxidasa 4/genética , NADPH Oxidasa 4/metabolismo , 3-Hidroxiacil-CoA Deshidrogenasas/metabolismo , Animales , Ácidos Grasos/metabolismo , Hexoquinasa/genética , Hexoquinasa/metabolismo , Peróxido de Hidrógeno/metabolismo , Metabolismo de los Lípidos , Masculino , Ratones , NADPH Oxidasa 4/deficiencia , Oxidación-Reducción , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Condicionamiento Físico Animal , Piruvato Deshidrogenasa Quinasa Acetil-Transferidora/genética , Piruvato Deshidrogenasa Quinasa Acetil-Transferidora/metabolismo , ARN Mensajero/metabolismo , Especies Reactivas de Oxígeno , Transcriptoma , Proteína Desacopladora 3/genética , Proteína Desacopladora 3/metabolismoRESUMEN
Obesity and insulin resistance are risk factors for nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease worldwide. Because no approved medication nor an accurate and noninvasive diagnosis is currently available for NAFLD, there is a clear need to better understand the link between obesity and NAFLD. Lipid accumulation during obesity is known to be associated with oxidative stress and inflammatory activation of liver macrophages (LMs). However, we show that although LMs do not become proinflammatory during obesity, they display signs of oxidative stress. In livers of both humans and mice, antioxidant nuclear factor erythroid 2-related factor 2 (NRF2) was down-regulated with obesity and insulin resistance, yielding an impaired response to lipid accumulation. At the molecular level, a microRNA-targeting NRF2 protein, miR-144, was elevated in the livers of obese insulin-resistant humans and mice, and specific silencing of miR-144 in murine and human LMs was sufficient to restore NRF2 protein expression and the antioxidant response. These results highlight the pathological role of LMs and their therapeutic potential to restore the impaired endogenous antioxidant response in obesity-associated NAFLD.
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Antioxidantes , Resistencia a la Insulina , Macrófagos del Hígado , Enfermedad del Hígado Graso no Alcohólico , Animales , Humanos , Hígado , Ratones , MicroARNs , Factor 2 Relacionado con NF-E2 , ObesidadRESUMEN
Cardiometabolic syndrome (CMS) describes the cluster of metabolic and cardiovascular diseases that are generally characterized by impaired glucose tolerance, intra-abdominal adiposity, dyslipidemia, and hypertension. CMS currently affects more than 25% of the world's population and the rates of diseases are rapidly rising. These CMS conditions represent critical risk factors for cardiovascular diseases including atherosclerosis, heart failure, myocardial infarction, and peripheral artery disease (PAD). Therefore, it is imperative to elucidate the underlying signaling involved in disease onset and progression. The c-Jun N-terminal Kinases (JNKs) are a family of stress signaling kinases that have been recently indicated in CMS. The purpose of this review is to examine the in vivo implications of JNK as a potential therapeutic target for CMS. As the constellation of diseases associated with CMS are complex and involve multiple tissues and environmental triggers, carefully examining what is known about the JNK pathway will be important for specificity in treatment strategies.
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Dislipidemias/genética , Intolerancia a la Glucosa/genética , Hipertensión/genética , Insulina/genética , MAP Quinasa Quinasa 4/genética , Tejido Adiposo/enzimología , Tejido Adiposo/patología , Adiposidad/genética , Animales , Citocinas/genética , Citocinas/metabolismo , Dislipidemias/enzimología , Dislipidemias/patología , Factores de Crecimiento de Fibroblastos/genética , Factores de Crecimiento de Fibroblastos/metabolismo , Regulación de la Expresión Génica , Intolerancia a la Glucosa/enzimología , Intolerancia a la Glucosa/patología , Humanos , Hipertensión/enzimología , Hipertensión/patología , Insulina/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Hígado/enzimología , Hígado/patología , MAP Quinasa Quinasa 4/deficiencia , Ratones , Ratones Noqueados , Músculo Esquelético/enzimología , Músculo Esquelético/patología , Transducción de Señal , SíndromeRESUMEN
Diseases related to impaired blood flow such as peripheral artery disease (PAD) impact nearly 10 million people in the United States alone, yet patients with clinical manifestations of PAD (e.g., claudication and limb ischemia) have limited treatment options. In ischemic tissues, stress kinases such as c-Jun N-terminal kinases (JNKs), are activated. Here, we show that inhibition of the JNK3 (Mapk10) in the neural compartment strikingly potentiates blood flow recovery from mouse hindlimb ischemia. JNK3 deficiency leads to upregulation of growth factors such as Vegfa, Pdgfb, Pgf, Hbegf and Tgfb3 in ischemic muscle by activation of the transcription factors Egr1/Creb1. JNK3 acts through Forkhead box O3 (Foxo3a) to suppress the activity of Egr1/Creb1 transcription regulators in vitro. In JNK3-deficient cells, Foxo3a is suppressed which leads to Egr1/Creb1 activation and upregulation of downstream growth factors. Collectively, these data suggest that the JNK3-Foxo3a-Egr1/Creb1 axis coordinates the vascular remodeling response in peripheral ischemia.
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Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Proteína 1 de la Respuesta de Crecimiento Precoz/metabolismo , Miembro Posterior/irrigación sanguínea , Isquemia/metabolismo , Proteína Quinasa 10 Activada por Mitógenos/metabolismo , Neuronas/metabolismo , Animales , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteína 1 de la Respuesta de Crecimiento Precoz/genética , Proteína Forkhead Box O3/genética , Proteína Forkhead Box O3/metabolismo , Miembro Posterior/inervación , Miembro Posterior/metabolismo , Humanos , Isquemia/genética , Isquemia/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína Quinasa 10 Activada por Mitógenos/genética , Músculo Esquelético/metabolismo , Flujo Sanguíneo Regional , Transducción de SeñalRESUMEN
Mitochondrial respiration plays a crucial role in determining the metabolic state of brown adipose tissue (BAT), due to its direct roles in thermogenesis, as well as through additional mechanisms. Here, we show that respiration-dependent retrograde signaling from mitochondria to nucleus contributes to genetic and metabolic reprogramming of BAT. In mouse BAT, ablation of LRPPRC (LRP130), a potent regulator of mitochondrial transcription and respiratory capacity, triggers down-regulation of thermogenic genes, promoting a storage phenotype in BAT. This retrograde regulation functions by inhibiting the recruitment of PPARγ to the regulatory elements of thermogenic genes. Reducing cytosolic Ca2+ reverses the attenuation of thermogenic genes in brown adipocytes with impaired respiratory capacity, while induction of cytosolic Ca2+ is sufficient to attenuate thermogenic gene expression, indicating that cytosolic Ca2+ mediates mitochondria-nucleus crosstalk. Our findings suggest respiratory capacity governs thermogenic gene expression and BAT function via mitochondria-nucleus communication, which in turn leads to either a thermogenic or storage mode.
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Respiración de la Célula , Regulación de la Expresión Génica , Mitocondrias/genética , Mitocondrias/metabolismo , Transducción de Señal , Termogénesis/genética , Tejido Adiposo Pardo/metabolismo , Animales , Calcio/metabolismo , Ratones , Ratones Noqueados , Mitocondrias/ultraestructura , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , PPAR gamma/genética , PPAR gamma/metabolismo , Regiones Promotoras GenéticasRESUMEN
Endothelial dysfunction is a characteristic of many vascular related diseases such as hypertension. Peroxisome proliferator activated receptor gamma, coactivator 1α (PGC-1α) is a unique stress sensor that largely acts to promote adaptive responses. Therefore, we sought to define the role of endothelial PGC-1α in vascular function using mice with endothelial specific loss of function (PGC-1α EC KO) and endothelial specific gain of function (PGC-1α EC TG). Here we report that endothelial PGC-1α is suppressed in angiotensin-II (ATII)-induced hypertension. Deletion of endothelial PGC-1α sensitized mice to endothelial dysfunction and hypertension in response to ATII, whereas PGC-1α EC TG mice were protected. Mechanistically, PGC-1α promotes eNOS expression and activity, which is necessary for protection from ATII-induced dysfunction as mice either treated with an eNOS inhibitor (LNAME) or lacking eNOS were no longer responsive to transgenic endothelial PGC-1α expression. Finally, we determined that the orphan nuclear receptor, estrogen related receptor α (ERRα) is required to coordinate the PGC-1α -induced eNOS expression. In conclusion, endothelial PGC-1α expression protects from vascular dysfunction by promoting NO⢠bioactivity through ERRα induced expression of eNOS.
Asunto(s)
Células Endoteliales/metabolismo , Regulación Enzimológica de la Expresión Génica , Hipertensión/metabolismo , Óxido Nítrico Sintasa de Tipo III/biosíntesis , Óxido Nítrico/biosíntesis , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Angiotensina II/efectos adversos , Angiotensina II/farmacología , Animales , Línea Celular , Células Endoteliales/patología , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/metabolismo , Humanos , Hipertensión/inducido químicamente , Hipertensión/genética , Hipertensión/patología , Ratones , Ratones Noqueados , Óxido Nítrico/genética , Óxido Nítrico Sintasa de Tipo III/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genéticaRESUMEN
Smooth muscle sphincters exhibit basal tone and control passage of contents through organs such as the gastrointestinal tract; loss of this tone leads to disorders such as faecal incontinence. However, the molecular mechanisms underlying this tone remain unknown. Here, we show that deletion of myosin light-chain kinases (MLCK) in the smooth muscle cells from internal anal sphincter (IAS-SMCs) abolishes basal tone, impairing defecation. Pharmacological regulation of ryanodine receptors (RyRs), L-type voltage-dependent Ca(2+) channels (VDCCs) or TMEM16A Ca(2+)-activated Cl(-) channels significantly changes global cytosolic Ca(2+) concentration ([Ca(2+)]i) and the tone. TMEM16A deletion in IAS-SMCs abolishes the effects of modulators for TMEM16A or VDCCs on a RyR-mediated rise in global [Ca(2+)]i and impairs the tone and defecation. Hence, MLCK activation in IAS-SMCs caused by a global rise in [Ca(2+)]i via a RyR-TMEM16A-VDCC signalling module sets the basal tone. Targeting this module may lead to new treatments for diseases like faecal incontinence.
Asunto(s)
Canal Anal/metabolismo , Canales de Calcio Tipo L/metabolismo , Canales de Cloruro/metabolismo , Incontinencia Fecal/metabolismo , Hipotonía Muscular/metabolismo , Quinasa de Cadena Ligera de Miosina/genética , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Canal Anal/efectos de los fármacos , Canal Anal/fisiopatología , Animales , Anoctamina-1 , Betanecol/farmacología , Calcio/metabolismo , Canales de Calcio Tipo L/genética , Señalización del Calcio , Canales de Cloruro/genética , Defecación/efectos de los fármacos , Incontinencia Fecal/genética , Incontinencia Fecal/fisiopatología , Femenino , Regulación de la Expresión Génica , Humanos , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Contracción Muscular/efectos de los fármacos , Hipotonía Muscular/genética , Hipotonía Muscular/fisiopatología , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Músculo Liso/fisiopatología , Quinasa de Cadena Ligera de Miosina/deficiencia , Nifedipino/farmacología , Ácido Niflúmico/farmacología , Técnicas de Placa-Clamp , Canal Liberador de Calcio Receptor de Rianodina/genéticaRESUMEN
Vascular reactive oxygen species (ROS) are known to be involved in atherosclerosis development and progression. NADPH oxidase 4 (Nox4) is a constitutively active ROS-producing enzyme that is highly expressed in the vascular endothelium. Nox4 is unique in its biology and has been implicated in vascular repair, however, the role of Nox4 in atherosclerosis is unknown. Therefore, to determine the effect of endothelial Nox4 on development of atherosclerosis, Apoe E-/- mice +/- endothelial Nox4 (ApoE-/- + EC Nox4) were fed a high cholesterol/high fat (Western) diet for 24 weeks. Significantly fewer atherosclerotic lesions were observed in the ApoE-/- + EC Nox4 mice as compared to the ApoE-/- littermates, which was most striking in the abdominal region of the aorta. In addition, markers of T cell populations were markedly different between the groups; T regulatory cell marker (FoxP3) was increased whereas T effector cell marker (T-bet) was decreased in aorta from ApoE-/- + EC Nox4 mice compared to ApoE-/- alone. We also observed decreased monokine induced by gamma interferon (MIG; CXCL9), a cytokine known to recruit and activate T cells, in plasma and tissue from ApoE-/- + EC Nox4 mice. To further investigate the link between endothelial Nox4 and MIG expression, we utilized cultured endothelial cells from our EC Nox4 transgenic mice and human cells with adenoviral overexpression of Nox4. In these cultured cells, upregulation of Nox4 attenuated endothelial cell MIG expression in response to interferon-gamma. Together these data suggest that endothelial Nox4 expression reduces MIG production and promotes a T cell distribution that favors repair over inflammation, leading to protection from atherosclerosis.