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BACKGROUND: Metabolic reprogramming and abnormal glucose metabolism are hallmarks of head and neck squamous cell carcinoma (HNSCC). Certain oncogenes can promote cancer-related metabolic changes, but understanding their crosstalk in HNSCC biology and treatment is essential for identifying predictive biomarkers and developing target therapies. METHODS: We assessed the value of survivin/BIRC5 as a radioresistance factor potentially modulated by glucose for predicting therapeutic sensitivity and prognosis of HNSCC in a cohort of 32 patients. Additionally, we conducted in vitro experiments to explore the role of survivin/BIRC5 in glucose metabolism concerning radiation response. RESULTS: Tumoral BIRC5 expression is associated with serum glucose and predicts locoregional disease-free survival and lower BIRC5 mRNA levels are associated with better outcomes. Upregulation of BIRC5 by radiation depends on glucose levels and provokes a pro-tumoral and radioresistant phenotype in surviving cells. CONCLUSIONS: Survivin/BIRC5 might be independently associated with the risk of recurrence in patients with HNSCC.
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Glucosa , Neoplasias de Cabeza y Cuello , Tolerancia a Radiación , Carcinoma de Células Escamosas de Cabeza y Cuello , Survivin , Humanos , Survivin/metabolismo , Survivin/genética , Masculino , Tolerancia a Radiación/genética , Neoplasias de Cabeza y Cuello/radioterapia , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/patología , Neoplasias de Cabeza y Cuello/genética , Femenino , Carcinoma de Células Escamosas de Cabeza y Cuello/radioterapia , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Persona de Mediana Edad , Anciano , Glucosa/metabolismo , Pronóstico , Línea Celular Tumoral , Supervivencia sin Enfermedad , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/genética , Proteínas Inhibidoras de la Apoptosis/metabolismo , Proteínas Inhibidoras de la Apoptosis/genética , AdultoRESUMEN
OBJECTIVE: Succinate and succinate receptor 1 (SUCNR1) are linked to fibrotic remodeling in models of non-alcoholic fatty liver disease (NAFLD), but whether they have roles beyond the activation of hepatic stellate cells remains unexplored. We investigated the succinate/SUCNR1 axis in the context of NAFLD specifically in hepatocytes. METHODS: We studied the phenotype of wild-type and Sucnr1-/- mice fed a choline-deficient high-fat diet to induce non-alcoholic steatohepatitis (NASH), and explored the function of SUCNR1 in murine primary hepatocytes and human HepG2 cells treated with palmitic acid. Lastly, plasma succinate and hepatic SUCNR1 expression were analyzed in four independent cohorts of patients in different NAFLD stages. RESULTS: Sucnr1 was upregulated in murine liver and primary hepatocytes in response to diet-induced NASH. Sucnr1 deficiency provoked both beneficial (reduced fibrosis and endoplasmic reticulum stress) and detrimental (exacerbated steatosis and inflammation and reduced glycogen content) effects in the liver, and disrupted glucose homeostasis. Studies in vitro revealed that hepatocyte injury increased Sucnr1 expression, which when activated improved lipid and glycogen homeostasis in damaged hepatocytes. In humans, SUCNR1 expression was a good determinant of NAFLD progression to advanced stages. In a population at risk of NAFLD, circulating succinate was elevated in patients with a fatty liver index (FLI) ≥60. Indeed, succinate had good predictive value for steatosis diagnosed by FLI, and improved the prediction of moderate/severe steatosis through biopsy when added to an FLI algorithm. CONCLUSIONS: We identify hepatocytes as target cells of extracellular succinate during NAFLD progression and uncover a hitherto unknown function for SUCNR1 as a regulator of hepatocyte glucose and lipid metabolism. Our clinical data highlight the potential of succinate and hepatic SUCNR1 expression as markers to diagnose fatty liver and NASH, respectively.
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Enfermedad del Hígado Graso no Alcohólico , Animales , Humanos , Ratones , Modelos Animales de Enfermedad , Fibrosis , Glucosa/metabolismo , Glucógeno/metabolismo , Hepatocitos/metabolismo , Hígado/metabolismo , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Succinatos/metabolismo , Succinatos/farmacologíaRESUMEN
Adipose tissue modulates energy homeostasis by secreting leptin, but little is known about the factors governing leptin production. We show that succinate, long perceived as a mediator of immune response and lipolysis, controls leptin expression via its receptor SUCNR1. Adipocyte-specific deletion of Sucnr1 influences metabolic health according to nutritional status. Adipocyte Sucnr1 deficiency impairs leptin response to feeding, whereas oral succinate mimics nutrient-related leptin dynamics via SUCNR1. SUCNR1 activation controls leptin expression via the circadian clock in an AMPK/JNK-C/EBPα-dependent manner. Although the anti-lipolytic role of SUCNR1 prevails in obesity, its function as a regulator of leptin signaling contributes to the metabolically favorable phenotype in adipocyte-specific Sucnr1 knockout mice under standard dietary conditions. Obesity-associated hyperleptinemia in humans is linked to SUCNR1 overexpression in adipocytes, which emerges as the major predictor of adipose tissue leptin expression. Our study establishes the succinate/SUCNR1 axis as a metabolite-sensing pathway mediating nutrient-related leptin dynamics to control whole-body homeostasis.
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Relojes Circadianos , Leptina , Animales , Humanos , Ratones , Adipocitos/metabolismo , Metabolismo Energético/fisiología , Leptina/metabolismo , Ratones Noqueados , Obesidad/metabolismo , Succinatos/metabolismoRESUMEN
Background: Coronavirus-19 (COVID-19) disease is driven by an unchecked immune response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus which alters host mitochondrial-associated mechanisms. Compromised mitochondrial health results in abnormal reprogramming of glucose metabolism, which can disrupt extracellular signalling. We hypothesized that examining mitochondrial energy-related signalling metabolites implicated in host immune response to SARS-CoV-2 infection would provide potential biomarkers for predicting the risk of severe COVID-19 illness. Methods: We used a semi-targeted serum metabolomics approach in 273 patients with different severity grades of COVID-19 recruited at the acute phase of the infection to determine the relative abundance of tricarboxylic acid (Krebs) cycle-related metabolites with known extracellular signaling properties (pyruvate, lactate, succinate and α-ketoglutarate). Abundance levels of energy-related metabolites were evaluated in a validation cohort (n=398) using quantitative fluorimetric assays. Results: Increased levels of four energy-related metabolites (pyruvate, lactate, a-ketoglutarate and succinate) were found in critically ill COVID-19 patients using semi-targeted and targeted approaches (p<0.05). The combined strategy proposed herein enabled us to establish that circulating pyruvate levels (p<0.001) together with body mass index (p=0.025), C-reactive protein (p=0.039), D-Dimer (p<0.001) and creatinine (p=0.043) levels, are independent predictors of critical COVID-19. Furthermore, classification and regression tree (CART) analysis provided a cut-off value of pyruvate in serum (24.54 µM; p<0.001) as an early criterion to accurately classify patients with critical outcomes. Conclusion: Our findings support the link between COVID-19 pathogenesis and immunometabolic dysregulation, and show that fluorometric quantification of circulating pyruvate is a cost-effective clinical decision support tool to improve patient stratification and prognosis prediction.
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COVID-19 , Biomarcadores , Proteína C-Reactiva , Creatinina , Glucosa , Humanos , Ácidos Cetoglutáricos , Lactatos , Pronóstico , Ácido Pirúvico , SARS-CoV-2 , Succinatos , Ácidos TricarboxílicosRESUMEN
BACKGROUND: Succinate is produced by both human cells and by gut bacteria and couples metabolism to inflammation as an extracellular signaling transducer. Circulating succinate is elevated in patients with obesity and type 2 diabetes and is linked to numerous complications, yet no studies have specifically addressed the contribution of gut microbiota to systemic succinate or explored the consequences of reducing intestinal succinate levels in this setting. RESULTS: Using germ-free and microbiota-depleted mouse models, we show that the gut microbiota is a significant source of circulating succinate, which is elevated in obesity. We also show in vivo that therapeutic treatments with selected bacteria diminish the levels of circulating succinate in obese mice. Specifically, we demonstrate that Odoribacter laneus is a promising probiotic based on its ability to deplete succinate and improve glucose tolerance and the inflammatory profile in two independent models of obesity (db/db mice and diet-induced obese mice). Mechanistically, this is partly mediated by the succinate receptor 1. Supporting these preclinical findings, we demonstrate an inverse correlation between plasma and fecal levels of succinate in a cohort of patients with severe obesity. We also show that plasma succinate, which is associated with several components of metabolic syndrome including waist circumference, triglycerides, and uric acid, among others, is a primary determinant of insulin sensitivity evaluated by the euglycemic-hyperinsulinemic clamp. CONCLUSIONS: Overall, our work uncovers O. laneus as a promising next-generation probiotic to deplete succinate and improve glucose tolerance and obesity-related inflammation. Video Abstract.
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Glucemia , Diabetes Mellitus Tipo 2 , Animales , Bacteroidetes , Diabetes Mellitus Tipo 2/microbiología , Dieta Alta en Grasa , Humanos , Inflamación , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Obesidad/etiología , Ácido SuccínicoAsunto(s)
Péptido 1 Similar al Glucagón/farmacología , Péptido 2 Similar al Glucagón/farmacología , Obesidad/dietoterapia , Obesidad/tratamiento farmacológico , Adulto , Estudios de Cohortes , Femenino , Péptido 1 Similar al Glucagón/metabolismo , Péptido 1 Similar al Glucagón/uso terapéutico , Péptido 2 Similar al Glucagón/metabolismo , Péptido 2 Similar al Glucagón/uso terapéutico , Humanos , Masculino , Microbiota/efectos de los fármacos , Microbiota/fisiología , Persona de Mediana Edad , Estudios Prospectivos , Programas de Reducción de Peso/métodos , Programas de Reducción de Peso/normas , Programas de Reducción de Peso/estadística & datos numéricosRESUMEN
BACKGROUND: Succinate is produced by both host and microbiota, with a key role in the interplay of immunity and metabolism and an emerging role as a biomarker for inflammatory and metabolic disorders in middle-aged adults. The relationship between plasma succinate levels and cardiovascular disease (CVD) risk in young adults is unknown. METHODS: Cross-sectional study in 100 (65% women) individuals aged 18-25 years from the ACTIvating Brown Adipose Tissue through Exercise (ACTIBATE) study cohort. CVD risk factors, body composition, dietary intake, basal metabolic rate, and cardiorespiratory fitness were assessed by routine methods. Plasma succinate was measured with an enzyme-based assay. Brown adipose tissue (BAT) was evaluated by positron emission tomography, and circulating oxylipins were assessed by targeted metabolomics. Fecal microbiota composition was analyzed in a sub-sample. RESULTS: Individuals with higher succinate levels had higher levels of visceral adipose tissue (VAT) mass (+ 42.5%), triglycerides (+ 63.9%), C-reactive protein (+ 124.2%), diastolic blood pressure (+ 5.5%), and pro-inflammatory omega-6 oxylipins than individuals with lower succinate levels. Succinate levels were also higher in metabolically unhealthy individuals than in healthy overweight/obese peers. Succinate levels were not associated with BAT volume or activity or with fecal microbiota composition and diversity. CONCLUSIONS: Plasma succinate levels are linked to a specific pro-inflammatory omega-6 signature pattern and higher VAT levels, and seem to reflect the cardiovascular status of young adults.
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Enfermedades Cardiovasculares/sangre , Ácido Succínico/sangre , Adiposidad , Adolescente , Adulto , Factores de Edad , Biomarcadores/sangre , Presión Sanguínea , Proteína C-Reactiva/análisis , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/fisiopatología , Estudios Transversales , Femenino , Microbioma Gastrointestinal , Factores de Riesgo de Enfermedad Cardiaca , Humanos , Mediadores de Inflamación/sangre , Grasa Intraabdominal/fisiopatología , Masculino , Oxilipinas/sangre , Ensayos Clínicos Controlados Aleatorios como Asunto , Medición de Riesgo , Triglicéridos/sangre , Regulación hacia Arriba , Adulto JovenRESUMEN
There has been an explosion of interest in the signaling capacity of energy metabolites. A prime example is the Krebs cycle substrate succinate, an archetypal respiratory substrate with functions beyond energy production as an intracellular and extracellular signaling molecule. Long associated with inflammation, emerging evidence supports a key role for succinate in metabolic processes relating to energy management. As the natural ligand for SUCNR1, a G protein-coupled receptor, succinate is akin to hormones and likely functions as a reporter of metabolism and stress. In this review, we reconcile new and old observations to outline a regulatory role for succinate in metabolic homeostasis. We highlight the importance of the succinate-SUCNR1 axis in metabolic diseases as an integrator of macrophage immune response, and we discuss new metabolic functions recently ascribed to succinate in specific tissues. Because circulating succinate has emerged as a promising biomarker in chronic metabolic diseases, a better understanding of the physiopathological role of the succinate-SUCNR1 axis in metabolism might open new avenues for clinical use in patients with obesity or diabetes.
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Ácido Succínico , Animales , Metabolismo Energético , Homeostasis , Humanos , Receptores Acoplados a Proteínas GRESUMEN
Adipose-derived mesenchymal stem cells (ASCs) are a promising option for the treatment of obesity and its metabolic co-morbidities. Despite the recent identification of brown adipose tissue (BAT) as a potential target in the management of obesity, the use of ASCs isolated from BAT as a therapy for patients with obesity has not yet been explored. Metabolic activation of BAT has been shown to have not only thermogenic effects, but it also triggers the secretion of factors that confer protection against obesity. Herein, we isolated and characterized ASCs from the visceral adipose tissue surrounding a pheochromocytoma (IB-hASCs), a model of inducible BAT in humans. We then compared the anti-obesity properties of IB-hASCs and human ASCs isolated from visceral white adipose tissue (W-hASCs) in a murine model of diet-induced obesity. We found that both ASC therapies mitigated the metabolic abnormalities of obesity to a similar extent, including reducing weight gain and improving glucose tolerance. However, infusion of IB-hASCs was superior to W-hASCs in suppressing lipogenic and inflammatory markers, as well as preserving insulin secretion. Our findings provide evidence for the metabolic benefits of visceral ASC infusion and support further studies on IB-hASCs as a therapeutic option for obesity-related comorbidities.
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Tejido Adiposo Blanco/patología , Dieta , Obesidad/patología , Células Madre/patología , Neoplasias de las Glándulas Suprarrenales/patología , Animales , Biomarcadores/metabolismo , Femenino , Regulación de la Expresión Génica , Glucosa/metabolismo , Humanos , Inflamación/genética , Metabolismo de los Lípidos/genética , Masculino , Ratones Endogámicos C57BL , Persona de Mediana Edad , Feocromocitoma/patología , Aumento de PesoRESUMEN
Head and neck squamous cell carcinoma (HNSCC) is characterized by high rates of mortality and treatment-related morbidity, underscoring the urgent need for innovative and safe treatment strategies and diagnosis practices. Mitochondrial dysfunction is a hallmark of cancer and can lead to the accumulation of tricarboxylic acid cycle intermediates, such as succinate, which function as oncometabolites. In addition to its role in cancer development through epigenetic events, succinate is an extracellular signal transducer that modulates immune response, angiogenesis and cell invasion by activating its cognate receptor SUCNR1. Here, we explored the potential value of the circulating succinate and related genes in HNSCC diagnosis and prognosis. We determined the succinate levels in the serum of 66 pathologically confirmed, untreated patients with HNSCC and 20 healthy controls. We also surveyed the expression of the genes related to succinate metabolism and signaling in tumoral and nontumoral adjacent tissue and in normal mucosa from 50 patients. Finally, we performed immunohistochemical analysis of SUCNR1 in mucosal samples. The results showed that the circulating levels of succinate were higher in patients with HNSCC than in the healthy controls. Additionally, the expression of SUCNR1, HIF-1α, succinate dehydrogenase (SDH) A, and SDHB was higher in the tumor tissue than in the matched normal mucosa. Consistent with this, immunohistochemical analysis revealed an increase in SUCNR1 protein expression in tumoral and nontumoral adjacent tissue. High SUCNR1 and SDHA expression levels were associated with poor locoregional control, and the locoregional recurrence-free survival rate was significantly lower in patients with high SUCNR1 and SDHA expression than in their peers with lower levels (77.1% [95% CI: 48.9-100.0] vs. 16.7% [95% CI: 0.0-44.4], p = 0.018). Thus, the circulating succinate levels are elevated in HNSCC and high SUCNR1/SDHA expression predicts poor locoregional disease-free survival, identifying this oncometabolite as a potentially valuable noninvasive biomarker for HNSCC diagnosis and prognosis.
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OBJECTIVE: To explore the meal response of circulating succinate in patients with obesity and type 2 diabetes undergoing bariatric surgery and to examine the role of gastrointestinal glucose sensing in succinate dynamics in healthy subjects. RESEARCH DESIGN AND METHODS: Cohort I comprised 45 patients with morbid obesity and type 2 diabetes (BMI 39.4 ± 1.9 kg/m2) undergoing metabolic surgery. Cohort II was a confirmatory cohort of 13 patients (BMI 39.3 ± 1.4 kg/m2) undergoing gastric bypass surgery. Cohort III comprised 15 healthy subjects (BMI 26.4 ± 0.5 kg/m2). Cohorts I and II completed a 2-h mixed-meal tolerance test (MTT) before the intervention and at 1 year of follow-up, and cohort II also completed a 3-h lipid test (LT). Cohort III underwent a 3-h oral glucose tolerance test (OGTT) and an isoglycemic intravenous glucose infusion (IIGI) study. RESULTS: In cohort I, succinate response to MTT at follow-up was greater than before the intervention (P < 0.0001). This response was confirmed in cohort II with a greater increase after 1 year of surgery (P = 0.009). By contrast, LT did not elicit a succinate response. Changes in succinate response were associated with changes in the area under the curve of glucose (r = 0.417, P < 0.0001) and insulin (r = 0.204, P = 0.002). In cohort III, glycemia, per se, stimulated a plasma succinate response (P = 0.0004), but its response was greater in the OGTT (P = 0.02; OGTT versus IIGI). CONCLUSIONS: The meal-related response of circulating succinate in patients with obesity and type 2 diabetes is recovered after metabolic surgery.
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Cirugía Bariátrica , Diabetes Mellitus Tipo 2/cirugía , Ingestión de Alimentos/fisiología , Obesidad Mórbida/cirugía , Ácido Succínico/sangre , Adulto , Anciano , Glucemia/metabolismo , Estudios de Cohortes , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/complicaciones , Técnicas de Diagnóstico Endocrino/normas , Femenino , Estudios de Seguimiento , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/sangre , Masculino , Comidas , Persona de Mediana Edad , Obesidad Mórbida/sangre , Obesidad Mórbida/complicaciones , Valores de Referencia , Ácido Succínico/normas , Adulto JovenRESUMEN
OBJECTIVE: To determine the potential use of baseline circulating succinate to predict type 2 diabetes remission after bariatric surgery. RESEARCH DESIGN AND METHODS: Forty-five obese patients with diabetes were randomly assigned to Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), or laparoscopic greater curvature plication. Anthropometric parameters were evaluated, and a complete biochemical analysis including circulating serum succinate concentrations was performed at baseline and 1 year after surgery. The results were externally validated in a second cohort including 88 obese patients with diabetes assigned to RYGB or SG based on clinical criteria. RESULTS: Succinate baseline concentrations were an independent predictor of diabetes remission after bariatric surgery. Patients achieving remission after 1 year had lower levels of baseline succinate (47.8 [37.6-64.6] µmol/L vs. 64.1 [52.5-82.9] µmol/L; P = 0.018). Moreover, succinate concentrations were significantly decreased 1 year after surgery (58.9 [46.4-82.4] µmol/L vs. 46.0 [35.8-65.3] µmol/L, P = 0.005). In multivariate analysis, the best logistic regression model showed that baseline succinate (odds ratio [OR] 11.3, P = 0.031) and the type of surgery (OR 26.4, P = 0.010) were independently associated with remission. The C-statistic for this model was 0.899 (95% CI 0.809-0.989) in the derivation cohort, which significantly improved the prediction of remission compared with current available scores, and 0.729 (95% CI 0.612-0.846) in the validation cohort. Interestingly, patients had a different response to the type of surgery according to baseline succinate, with significant differences in remission rates. CONCLUSIONS: Circulating succinate is reduced after bariatric surgery. Baseline succinate levels have predictive value for diabetes remission independently of previously described presurgical factors and improve upon the current available scores to predict remission.
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Cirugía Bariátrica , Biomarcadores/sangre , Diabetes Mellitus Tipo 2/cirugía , Obesidad/cirugía , Ácido Succínico/sangre , Adulto , Anciano , Cirugía Bariátrica/métodos , Estudios de Cohortes , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/diagnóstico , Femenino , Humanos , Laparoscopía/métodos , Masculino , Persona de Mediana Edad , Obesidad/sangre , Obesidad/complicaciones , Obesidad/diagnóstico , Periodo Preoperatorio , Pronóstico , Inducción de Remisión , Resultado del Tratamiento , Pérdida de PesoRESUMEN
Succinate is a signaling metabolite sensed extracellularly by succinate receptor 1 (SUNCR1). The accumulation of succinate in macrophages is known to activate a pro-inflammatory program; however, the contribution of SUCNR1 to macrophage phenotype and function has remained unclear. Here we found that activation of SUCNR1 had a critical role in the anti-inflammatory responses in macrophages. Myeloid-specific deficiency in SUCNR1 promoted a local pro-inflammatory phenotype, disrupted glucose homeostasis in mice fed a normal chow diet, exacerbated the metabolic consequences of diet-induced obesity and impaired adipose-tissue browning in response to cold exposure. Activation of SUCNR1 promoted an anti-inflammatory phenotype in macrophages and boosted the response of these cells to type 2 cytokines, including interleukin-4. Succinate decreased the expression of inflammatory markers in adipose tissue from lean human subjects but not that from obese subjects, who had lower expression of SUCNR1 in adipose-tissue-resident macrophages. Our findings highlight the importance of succinate-SUCNR1 signaling in determining macrophage polarization and assign a role to succinate in limiting inflammation.
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Inflamación/inmunología , Macrófagos/inmunología , Obesidad/inmunología , Receptores Acoplados a Proteínas G/inmunología , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/inmunología , Tejido Adiposo/metabolismo , Animales , Células Cultivadas , Citocinas/genética , Citocinas/inmunología , Citocinas/metabolismo , Perfilación de la Expresión Génica/métodos , Humanos , Inflamación/genética , Inflamación/metabolismo , Macrófagos/metabolismo , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Obesidad/genética , Obesidad/metabolismo , Receptores Acoplados a Proteínas G/deficiencia , Receptores Acoplados a Proteínas G/genética , Ácido Succínico/inmunología , Ácido Succínico/metabolismo , Ácido Succínico/farmacología , Células THP-1RESUMEN
BACKGROUND: A functional population of adipocyte precursors, termed adipose-derived stromal/stem cells (ASCs), is crucial for proper adipose tissue (AT) expansion, lipid handling, and prevention of lipotoxicity in response to chronic positive energy balance. We previously showed that obese human subjects contain a dysfunctional pool of ASCs. Elucidation of the mechanisms underlying abnormal ASC function might lead to therapeutic interventions for prevention of lipotoxicity by improving the adipogenic capacity of ASCs. METHODS: Using epigenome-wide association studies, we explored the impact of obesity on the methylation signature of human ASCs and their differentiated counterparts. Mitochondrial phenotyping of lean and obese ASCs was performed. TBX15 loss- and gain-of-function experiments were carried out and western blotting and electron microscopy studies of mitochondria were performed in white AT biopsies from lean and obese individuals. RESULTS: We found that DNA methylation in adipocyte precursors is significantly modified by the obese environment, and adipogenesis, inflammation, and immunosuppression were the most affected pathways. Also, we identified TBX15 as one of the most differentially hypomethylated genes in obese ASCs, and genetic experiments revealed that TBX15 is a regulator of mitochondrial mass in obese adipocytes. Accordingly, morphological analysis of AT from obese subjects showed an alteration of the mitochondrial network, with changes in mitochondrial shape and number. CONCLUSIONS: We identified a DNA methylation signature in adipocyte precursors associated with obesity, which has a significant impact on the metabolic phenotype of mature adipocytes.
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Adipocitos/patología , Tejido Adiposo/patología , Metilación de ADN , Mitocondrias/patología , Obesidad/genética , Obesidad/patología , Células Madre/metabolismo , Células Madre/patología , Adipocitos/metabolismo , Adipogénesis , Adulto , Femenino , Humanos , Inflamación/genética , Inflamación/patología , Mitocondrias/genética , Estrés Oxidativo , Delgadez/genética , Delgadez/patologíaRESUMEN
OBJECTIVE: ß-secretase/ß-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a key enzyme involved in Alzheimer's disease that has recently been implicated in insulin-independent glucose uptake in myotubes. However, it is presently unknown whether BACE1 and the product of its activity, soluble APPß (sAPPß), contribute to lipid-induced inflammation and insulin resistance in skeletal muscle cells. MATERIALS/METHODS: Studies were conducted in mouse C2C12 myotubes, skeletal muscle from Bace1-/-mice and mice treated with sAPPß and adipose tissue and plasma from obese and type 2 diabetic patients. RESULTS: We show that BACE1 inhibition or knockdown attenuates palmitate-induced endoplasmic reticulum (ER) stress, inflammation, and insulin resistance and prevents the reduction in Peroxisome Proliferator-Activated Receptor γ Co-activator 1α (PGC-1α) and fatty acid oxidation caused by palmitate in myotubes. The effects of palmitate on ER stress, inflammation, insulin resistance, PGC-1α down-regulation, and fatty acid oxidation were mimicked by soluble APPß in vitro. BACE1 expression was increased in subcutaneous adipose tissue of obese and type 2 diabetic patients and this was accompanied by a decrease in PGC-1α mRNA levels and by an increase in sAPPß plasma levels of obese type 2 diabetic patients compared to obese non-diabetic subjects. Acute sAPPß administration to mice reduced PGC-1α levels and increased inflammation in skeletal muscle and decreased insulin sensitivity. CONCLUSIONS: Collectively, these findings indicate that the BACE1 product sAPPß is a key determinant in ER stress, inflammation and insulin resistance in skeletal muscle and gluconeogenesis in liver.
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Secretasas de la Proteína Precursora del Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/metabolismo , Estrés del Retículo Endoplásmico/fisiología , Inflamación/metabolismo , Insulina/metabolismo , Músculo Esquelético/metabolismo , Transducción de Señal/fisiología , Animales , Línea Celular , Células Cultivadas , Estrés del Retículo Endoplásmico/efectos de los fármacos , Humanos , Resistencia a la Insulina/fisiología , Masculino , Ratones , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/efectos de los fármacos , FN-kappa B/metabolismo , Ácido Palmítico/farmacología , Transducción de Señal/efectos de los fármacosRESUMEN
Gut microbiota-related metabolites are potential clinical biomarkers for cardiovascular disease (CVD). Circulating succinate, a metabolite produced by both microbiota and the host, is increased in hypertension, ischemic heart disease, and type 2 diabetes. We aimed to analyze systemic levels of succinate in obesity, a major risk factor for CVD, and its relationship with gut microbiome. We explored the association of circulating succinate with specific metagenomic signatures in cross-sectional and prospective cohorts of Caucasian Spanish subjects. Obesity was associated with elevated levels of circulating succinate concomitant with impaired glucose metabolism. This increase was associated with specific changes in gut microbiota related to succinate metabolism: a higher relative abundance of succinate-producing Prevotellaceae (P) and Veillonellaceae (V), and a lower relative abundance of succinate-consuming Odoribacteraceae (O) and Clostridaceae (C) in obese individuals, with the (P + V/O + C) ratio being a main determinant of plasma succinate. Weight loss intervention decreased (P + V/O + C) ratio coincident with the reduction in circulating succinate. In the spontaneous evolution after good dietary advice, alterations in circulating succinate levels were linked to specific metagenomic signatures associated with carbohydrate metabolism and energy production with independence of body weight change. Our data support the importance of microbe-microbe interactions for the metabolite signature of gut microbiome and uncover succinate as a potential microbiota-derived metabolite related to CVD risk.
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Microbioma Gastrointestinal , Obesidad/microbiología , Ácido Succínico/sangre , Adulto , Anciano , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/metabolismo , Biomarcadores/sangre , Estudios Transversales , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/microbiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obesidad/sangre , Filogenia , Estudios ProspectivosRESUMEN
BACKGROUND: The primary purpose of this study was to investigate the significance of pretreatment glycemic parameters in the prognosis of head and neck squamous cell carcinoma (HNSCC). METHODS: Plasma samples of 71 patients with untreated HNSCC were obtained at the time of diagnosis. The prognostic value of fasting insulin, glucose, glycosylated hemoglobin levels, and the homeostatic model of risk assessment-insulin resistance (HOMA-IR) was evaluated toward disease-free survival. RESULTS: High HOMA-IR levels were associated with poor disease-free survival in intermediate-advanced stage tumors. Kaplan-Meier curves showed lower disease-free survival rates in patients with high HOMA-IR than in patients with low levels. In patients with intermediate-advanced stage tumors, multivariate analysis revealed that those with an HOMA-IR >2.974 presented a 2.7 times higher risk of poor outcome (95% confidence interval [CI] 1.023-7.341; P = .045). CONCLUSION: The HOMA-IR is independently associated with disease-free survival in patients with HNSCC. We found an optimal HOMA-IR cutoff value for disease-free survival in patients with intermediate-advanced HNSCC.
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Carcinoma de Células Escamosas/sangre , Carcinoma de Células Escamosas/mortalidad , Neoplasias de Cabeza y Cuello/sangre , Neoplasias de Cabeza y Cuello/mortalidad , Resistencia a la Insulina , Adulto , Anciano , Glucemia/análisis , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/terapia , Estudios de Cohortes , Terapia Combinada , Supervivencia sin Enfermedad , Femenino , Neoplasias de Cabeza y Cuello/patología , Neoplasias de Cabeza y Cuello/terapia , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Invasividad Neoplásica/patología , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Pronóstico , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Medición de Riesgo , Carcinoma de Células Escamosas de Cabeza y Cuello , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
M2 macrophages, innate lymphoid type 2 cells (ILC2s), eosinophils, Tregs, and invariant NK T cells (iNKT cells) all help to control adipose tissue inflammation, while M1 macrophages, TNF, and other inflammatory cytokines drive inflammation and insulin resistance in obesity. Stromal cells regulate leukocyte responses in lymph nodes, but the role of stromal cells in adipose tissue inflammation is unknown. PDGFRα+ stromal cells are major producers of IL-33 in adipose tissue. Here, we show that mesenchymal cadherin-11 modulates stromal fibroblast function. Cadherin-11-deficient mice displayed increased stromal production of IL-33, with concomitant enhancements in ILC2s and M2 macrophages that helped control adipose tissue inflammation. Higher expression levels of IL-33 in cadherin-11-deficient mice mediated ILC2 activation, resulting in higher IL-13 expression levels and M2 macrophage expansion in adipose tissue. Consistent with reduced adipose tissue inflammation, cadherin-11-deficient mice were protected from obesity-induced glucose intolerance and adipose tissue fibrosis. Importantly, anti-cadherin-11 mAb blockade similarly improved inflammation and glycemic control in obese WT mice. These results suggest that stromal fibroblasts expressing cadherin-11 regulate adipose tissue inflammation and thus highlight cadherin-11 as a potential therapeutic target for the management of obesity.