RESUMEN
Radiation induces the generation of platelet-activating factor receptor (PAF-R) ligands, including PAF and oxidized phospholipids. Alternatively, PAF is also synthesized by the biosynthetic enzymes lysophosphatidylcholine acyltransferases (LPCATs) which are expressed by tumor cells including melanoma. The activation of PAF-R by PAF and oxidized lipids triggers a survival response protecting tumor cells from radiation-induced cell death, suggesting the involvement of the PAF/PAF-R axis in radioresistance. Here, we investigated the role of LPCATs in the melanoma cell radiotherapy response. LPCAT is a family of four enzymes, LPCAT1-4, and modular nucleic acid nanoparticles (NANPs) allowed for the simultaneous silencing of all four LPCATs. We found that the in vitro simultaneous silencing of all four LPCAT transcripts by NANPs enhanced the therapeutic effects of radiation in melanoma cells by increasing cell death, reducing long-term cell survival, and activating apoptosis. Thus, we propose that NANPs are an effective strategy for improving radiotherapy efficacy in melanomas.
Asunto(s)
1-Acilglicerofosfocolina O-Aciltransferasa , Silenciador del Gen , Melanoma , Nanopartículas , Proteínas de Neoplasias , Ácidos Nucleicos , 1-Acilglicerofosfocolina O-Aciltransferasa/antagonistas & inhibidores , 1-Acilglicerofosfocolina O-Aciltransferasa/biosíntesis , Línea Celular Tumoral , Humanos , Melanoma/tratamiento farmacológico , Melanoma/enzimología , Nanopartículas/química , Nanopartículas/uso terapéutico , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/biosíntesis , Ácidos Nucleicos/química , Ácidos Nucleicos/farmacologíaRESUMEN
Two commercial exogenous pulmonary surfactants, Curosurf and Survanta, are investigated. Their thermotropic behavior and associated structural changes for the samples in bulk are characterized and described. For Survanta, the obtained results of differential scanning calorimetry showed a thermogram with three peaks on heating and only a single peak on cooling. Curosurf on the other hand, presents calorimetric thermograms with only one peak in both the heating and cooling scans. This distinct thermotropic behavior between the two pulmonary surfactants, a consequence of their particular compositions, is associated with structural changes that were evaluated by simultaneous small- and wide-angle X-ray scattering experiments with in situ temperature variation. Interestingly, for temperatures below â¼35 °C for Curosurf and â¼53 °C for Survanta, the scattering data indicated the coexistence of two lamellar phases with different carbon chain organizations. For temperatures above these limits, the coexistence of phases disappears, giving rise to a fluid phase in both pulmonary surfactants, with multilamelar vesicles for Curosurf and unilamellar vesicles for Survanta. This process is quasi-reversible under cooling, and advanced data analysis for the scattering data indicated differences in the structural and elastic properties of the pulmonary surfactants. The detailed and systematic investigation shown in this work expands on the knowledge of the structure and thermodynamic behavior of Curosurf and Survanta, being relevant from both physiological and biophysical perspectives and also providing a basis for further studies on other types of pulmonary surfactants.
Asunto(s)
Surfactantes Pulmonares , Animales , Rastreo Diferencial de Calorimetría , Bovinos , Pulmón , Tensoactivos , Porcinos , TermodinámicaRESUMEN
The Commelina erecta L. (C. erecta) also known as erva-de-santa-luzia is reported by local population to have medical properties against some pathological conditions. In this study, two extracts of C. erecta leaves (aqueous and ethanolic) were phytochemically analysed and evaluated for their in-vitro antioxidant activities by DPPH, TBARS, NO assays and cell viability assays. The ultra-high performance liquid chromatography followed by tandem mass spectrometry analysis showed the presence of rutin and caffeic acid in aqueous and ethanolic extract. The total polyphenols in aqueous and ethanolic extracts found were 142.7 ± 3.0 and 123.1 ± 5.8 µg/mL of GAE, respectively. The ethanolic extract (5 mg/mL) inhibits TBARS by 33.8%, and the aqueous extract (5 mg/mL) exhibited scavenger property against nitric oxide derivatives to an extent of 77.8%. In cell culture, both extracts improved cell survivability under H2O2 induced oxidative stress. Thus, C. erecta extract is a good candidate to become a phytotherapic medicine.
Asunto(s)
Antioxidantes/farmacología , Ácidos Cafeicos/análisis , Cromatografía Líquida de Alta Presión/métodos , Commelina/química , Extractos Vegetales/farmacología , Rutina/análisis , Animales , Técnicas de Cultivo de Célula , Humanos , Peróxido de Hidrógeno/farmacocinética , Estrés Oxidativo/efectos de los fármacos , Fenoles/análisis , Fitoquímicos/análisis , Hojas de la Planta/química , Polifenoles/análisis , Espectrometría de Masas en Tándem/métodosRESUMEN
Radical mediated oxidation of polyunsaturated fatty acids (PUFA) is known to generate a series of polyoxygenated cyclic products (PUFA-On, n ≥ 3). Here, we describe the characterization of glutathione (GSH) conjugates bound to polyoxygenated docosahexaenoic (DHA-On, n = 3-9), arachidonic (ARA-On, n = 3-7), α-linolenic (ALA-O3), and linoleic (LA-O3) acid species. Similar conjugates were also characterized for N-acetylcysteine (NAC) and Cu,Zn-superoxide dismutase (SOD1). Extensive LC-MS/MS characterization using a synthetic α-linolenic hydroxy-endoperoxide (ALA-O3) derivative revealed at least two types of mechanisms leading to thiol adduction: a mechanism involving the nucleophilic attack by thiolate anion on 1,2-dioxolane to form a sulfenate ester-bonded conjugate and a mechanism involving cleavage of the dioxolane to form a α,ß-unsaturated carbonyl followed by the Michael addition reaction. Finally, we detected a GSH conjugate with hydroxy-endoperoxide derived from linoleic acid (LA-O3) in mice liver. In summary, our study reveals the formation of a series of thiol conjugates that are bound to highly oxygenated PUFA species. GSH conjugates described in our study may potentially play relevant roles in redox and inflammatory processes, especially under high oxygen tension conditions.
Asunto(s)
Ácidos Grasos Insaturados/química , Glutatión/química , Animales , Cromatografía Liquida , Ácidos Grasos Insaturados/metabolismo , Glutatión/aislamiento & purificación , Glutatión/metabolismo , Hígado/química , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Estructura Molecular , Oxidación-Reducción , Peróxidos/química , Peróxidos/metabolismo , Espectrometría de Masas en TándemRESUMEN
Mechanistic target of rapamycin complex (mTORC)1 activity is increased in adipose tissue of obese insulin-resistant mice, but its role in the regulation of tissue inflammation is unknown. Herein, we investigated the effects of adipocyte mTORC1 deficiency on adipose tissue inflammation and glucose homeostasis. For this, mice with adipocyte raptor deletion and controls fed a chow or a high-fat diet were evaluated for body mass, adiposity, glucose homeostasis, and adipose tissue inflammation. Despite reducing adiposity, adipocyte mTORC1 deficiency promoted hepatic steatosis, insulin resistance, and adipose tissue inflammation (increased infiltration of macrophages, neutrophils, and B lymphocytes; crown-like structure density; TNF-α, interleukin (IL)-6, and monocyte chemoattractant protein 1 expression; IL-1ß protein content; lipid peroxidation; and de novo ceramide synthesis). The anti-oxidant, N-acetylcysteine, partially attenuated, whereas treatment with de novo ceramide synthesis inhibitor, myriocin, completely blocked adipose tissue inflammation and nucleotide oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3)-inflammasome activation, but not hepatic steatosis and insulin resistance induced by adipocyte raptor deletion. Rosiglitazone treatment, however, completely abrogated insulin resistance induced by adipocyte raptor deletion. In conclusion, adipocyte mTORC1 deficiency induces adipose tissue inflammation and NLRP3-inflammasome activation by promoting oxidative stress and de novo ceramide synthesis. Such adipose tissue inflammation, however, is not an underlying cause of the insulin resistance displayed by these mice.
Asunto(s)
Adipocitos/metabolismo , Tejido Adiposo/patología , Ceramidas/biosíntesis , Inflamasomas/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/deficiencia , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Estrés Oxidativo , Adipocitos/efectos de los fármacos , Adipocitos/patología , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/metabolismo , Animales , Dieta Alta en Grasa/efectos adversos , Glucosa/metabolismo , Homeostasis/efectos de los fármacos , Diana Mecanicista del Complejo 2 de la Rapamicina/deficiencia , Ratones , Ratones Endogámicos C57BL , Estrés Oxidativo/efectos de los fármacosRESUMEN
Metastasis formation is a complex process, involving multiple crucial steps, which are controlled by different regulatory mechanisms. In this context, the contribution of cancer metabolism to the metastatic cascade is being increasingly recognized. This Review focuses on changes in lipid metabolism that contribute to metastasis formation in solid tumors. We discuss the molecular mechanisms by which lipids induce a pro-metastatic phenotype and explore the role of lipids in response to oxidative stress and as signaling molecules. Finally, we reflect on potential avenues to target lipid metabolism to improve the treatment of metastatic cancers.
Asunto(s)
Neoplasias , Humanos , Transducción de Señal , Estrés Oxidativo , LípidosRESUMEN
Lipids have essential functions as structural components of cellular membranes, as efficient energy storage molecules, and as precursors of signaling mediators. While deregulated glucose and amino acid metabolism in cancer have received substantial attention, the roles of lipids in the metabolic reprogramming of cancer cells are less well understood. However, since the first description of de novo fatty acid biosynthesis in cancer tissues almost 70 years ago, numerous studies have investigated the complex functions of altered lipid metabolism in cancer. Here, we will summarize the mechanisms by which oncogenic signaling pathways regulate fatty acid and cholesterol metabolism to drive rapid proliferation and protect cancer cells from environmental stress. The review also discusses the role of fatty acid metabolism in metabolic plasticity required for the adaptation to changing microenvironments during cancer progression and the connections between fatty acid and cholesterol metabolism and ferroptosis.
RESUMEN
Cholesterol is essential for the ability of cytotoxic T cells to eliminate cancer cells. In this issue of Cancer Cell, Yan et al. reveal how intra-tumoral cholesterol deficiency contributes to T cell exhaustion by inhibiting mTORC1 signaling. Moreover, they demonstrate that increasing cholesterol levels in chimeric antigen receptor (CAR)-T cells by blocking liver X receptor (LXR) leads to improved anti-tumor function.
Asunto(s)
Neoplasias , Receptores Quiméricos de Antígenos , Humanos , Microambiente Tumoral , Inmunoterapia Adoptiva , Neoplasias/terapia , Linfocitos T CitotóxicosRESUMEN
Total absence of adipose tissue (lipoatrophy) is associated with the development of severe metabolic disorders including hepatomegaly and fatty liver. Here, we sought to investigate the impact of severe lipoatrophy induced by deletion of peroxisome proliferator-activated receptor gamma (PPARγ) exclusively in adipocytes on lipid metabolism in mice. Untargeted lipidomics of plasma, gastrocnemius and liver uncovered a systemic depletion of the essential linoleic (LA) and α-linolenic (ALA) fatty acids from several lipid classes (storage lipids, glycerophospholipids, free fatty acids) in lipoatrophic mice. Our data revealed that such essential fatty acid depletion was linked to increased: 1) capacity for liver mitochondrial fatty acid ß-oxidation (FAO), 2) citrate synthase activity and coenzyme Q content in the liver, 3) whole-body oxygen consumption and reduced respiratory exchange rate in the dark period, and 4) de novo lipogenesis and carbon flux in the TCA cycle. The key role of de novo lipogenesis in hepatic steatosis was evidenced by an accumulation of stearic, oleic, sapienic and mead acids in liver. Our results thus indicate that the simultaneous activation of the antagonic processes FAO and de novo lipogenesis in liver may create a futile metabolic cycle leading to a preferential depletion of LA and ALA. Noteworthy, this previously unrecognized cycle may also explain the increased energy expenditure displayed by lipoatrophic mice, adding a new piece to the metabolic regulation puzzle in lipoatrophies.
Asunto(s)
Hígado Graso , Lipogénesis , Animales , Ratones , Ciclo del Sustrato , Metabolismo de los Lípidos , Hígado Graso/metabolismo , Ácido alfa-Linolénico/metabolismoRESUMEN
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive loss of motor neurons, systemic hypermetabolism, and inflammation. In this context, oxylipins have been investigated as signaling molecules linked to neurodegeneration, although their specific role in ALS remains unclear. Importantly, most methods focused on oxylipin analysis are based on low-resolution mass spectrometry, which usually confers high sensitivity, but not great accuracy for molecular characterization, as provided by high-resolution MS (HRMS). Here, we established an ultra-high performance liquid chromatography HRMS (LC-HRMS) method for simultaneous analysis of 126 oxylipins in plasma. Intra- and inter-day method validation showed high sensitivity (0.3-25 pg), accuracy and precision for more than 90% of quality controls. This method was applied in plasma of ALS rats overexpressing the mutant human Cu/Zn-superoxide dismutase gene (SOD1-G93A) at asymptomatic (ALS 70 days old) and symptomatic stages (ALS 120 days old), and their respective age-matched wild type controls. From the 56 oxylipins identified in plasma, 17 species were significantly altered. Remarkably, most of oxylipins linked to inflammation and oxidative stress derived from arachidonic acid (AA), like prostaglandins and mono-hydroxides, were increased in ALS 120 d rats. In addition, ketones derived from AA and linoleic acid (LA) were increased in both WT 120 d and ALS 120 d groups, supporting that age also modulates oxylipin metabolism in plasma. Interestingly, the LA-derived diols involved in fatty acid uptake and ß-oxidation, 9(10)-DiHOME and 12(13)-DiHOME, were decreased in ALS 120 d rats and showed significant synergic effects between age and disease factors. In summary, we validated a high-throughput LC-HRMS method for oxylipin analysis and provided a comprehensive overview of plasma oxylipins involved in ALS disease progression. Noteworthy, the oxylipins altered in plasma have potential to be investigated as biomarkers for inflammation and hypermetabolism in ALS.
Asunto(s)
Esclerosis Amiotrófica Lateral , Enfermedades Neurodegenerativas , Ratas , Humanos , Animales , Ratones , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/metabolismo , Oxilipinas , Espectrometría de Masas , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/metabolismo , Inflamación , Modelos Animales de Enfermedad , Ratones Transgénicos , Superóxido Dismutasa/genéticaRESUMEN
Hancornia speciosa Gomes (HS) is a Brazilian fruit tree used in inflammatory disorders by folk medicine. Here we sought to investigate the antioxidant and hepatoprotective properties of HS fruit juice in acetaminophen-induced hepatoxicity model in rats, as well as to perform a comprehensive chemical characterization of phenolics and metals by mass spectrometry. HS showed hepatoprotective and antioxidant activity by decreasing MDA and liver injury markers at healthy control levels. In addition, liver histopathological analysis revealed that HS decreases hepatocellular degeneration. Chemical characterization revealed 16 different phenolics, being chlorogenic acid (150 ± 5 µg/g) and rutin (120 ± 8 µg/g) the major phenolics in HS. Among the 14 micronutrients we identified, zinc and boron were the most abundant metals detected in HS. In line with previous studies involving liver diseases, our data supports evidence that such phenolics and metals present in HS may prevent liver injury induced by acetaminophen.
Asunto(s)
Apocynaceae , Enfermedad Hepática Inducida por Sustancias y Drogas , Acetaminofén/toxicidad , Animales , Antioxidantes/farmacología , Apocynaceae/química , Enfermedad Hepática Inducida por Sustancias y Drogas/tratamiento farmacológico , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Jugos de Frutas y Vegetales , Hígado , Fenoles/farmacología , Extractos Vegetales/química , Extractos Vegetales/farmacología , RatasRESUMEN
Cardiovascular manifestations account for marked morbi-mortality in autosomal dominant polycystic kidney disease (ADPKD). Pkd1- and Pkd2-deficient mice develop cardiac dysfunction, however the underlying mechanisms remain largely unclear. It is unknown whether impairment of polycystin-1 cleavage at the G-protein-coupled receptor proteolysis site, a significant ADPKD mutational mechanism, is involved in this process. We analyzed the impact of polycystin-1 cleavage on heart metabolism using Pkd1V/V mice, a model unable to cleave this protein and with early cardiac dysfunction. Pkd1V/V hearts showed lower levels of glucose and amino acids and higher lipid levels than wild-types, as well as downregulation of p-AMPK, p-ACCß, CPT1B-Cpt1b, Ppara, Nppa and Acta1. These findings suggested decreased fatty acid ß-oxidation, which was confirmed by lower oxygen consumption by Pkd1V/V isolated mitochondria using palmitoyl-CoA. Pkd1V/V hearts also presented increased oxygen consumption in response to glucose, suggesting that alternative substrates may be used to generate energy. Pkd1V/V hearts displayed a higher density of decreased-size mitochondria, a finding associated with lower MFN1, Parkin and BNIP3 expression. These derangements were correlated with increased apoptosis and inflammation but not hypertrophy. Notably, Pkd1V/V neonate cardiomyocytes also displayed shifts in oxygen consumption and p-AMPK downregulation, suggesting that, at least partially, the metabolic alterations are not induced by kidney dysfunction. Our findings reveal that disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice, expanding the understanding of heart dysfunction associated with Pkd1 deficiency and likely with human ADPKD.
Asunto(s)
Riñón Poliquístico Autosómico Dominante , Canales Catiónicos TRPP , Animales , Corazón , Ratones , Mitocondrias/metabolismo , Mutación , Riñón Poliquístico Autosómico Dominante/genética , Riñón Poliquístico Autosómico Dominante/metabolismo , Canales Catiónicos TRPP/genética , Canales Catiónicos TRPP/metabolismoRESUMEN
Dietary sugar is an important determinant of the development and progression of nonalcoholic fatty liver disease (NAFLD). However, the molecular mechanisms underlying the deleterious effects of sugar intake on NAFLD under energy-balanced conditions are still poorly understood. Here, we provide a comprehensive analysis of the liver lipidome and mechanistic insights into the pathogenesis of NAFLD induced by the chronic consumption of high-sugar diet (HSD). Newly weaned male Wistar rats were fed either a standard chow diet or an isocaloric HSD for 18 weeks. Livers were harvested for histological, oxidative stress, gene expression, and lipidomic analyses. Intake of HSD increased oxidative stress and induced severe liver injury, microvesicular steatosis, and ballooning degeneration of hepatocytes. Using untargeted lipidomics, we identified and quantified 362 lipid species in the liver. Rats fed with HSD displayed increased hepatic levels of triacylglycerol enriched in saturated and monounsaturated fatty acids, lipids related to mitochondrial function/structure (phosphatidylglycerol, cardiolipin, and ubiquinone), and acylcarnitine (an intermediate lipid of fatty acid beta-oxidation). HSD-fed animals also presented increased levels of some species of membrane lipids and a decreased content of phospholipids containing omega-6 fatty acids. These changes in the lipidome were associated with the downregulation of genes involved in fatty acid oxidation in the liver. In conclusion, our data suggest that the chronic intake of a HSD, even under isocaloric conditions, induces lipid overload, and inefficient/impaired fatty acid oxidation in the liver. Such events lead to marked disturbance in hepatic lipid metabolism and the development of NAFLD.
Asunto(s)
Dieta de Carga de Carbohidratos/efectos adversos , Metabolismo de los Lípidos , Hígado/metabolismo , Enfermedad del Hígado Graso no Alcohólico/etiología , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Animales , Lipidómica , Masculino , Redes y Vías Metabólicas , Ratas WistarRESUMEN
The nutrient sensors peroxisome proliferator-activated receptor γ (PPARγ) and mechanistic target of rapamycin complex 1 (mTORC1) closely interact in the regulation of adipocyte lipid storage. The precise mechanisms underlying this interaction and whether this extends to other metabolic processes and the endocrine function of adipocytes are still unknown. We investigated herein the involvement of mTORC1 as a mediator of the actions of the PPARγ ligand rosiglitazone in subcutaneous inguinal white adipose tissue (iWAT) mass, endocrine function, lipidome, transcriptome and branched-chain amino acid (BCAA) metabolism. Mice bearing regulatory associated protein of mTOR (Raptor) deletion and therefore mTORC1 deficiency exclusively in adipocytes and littermate controls were fed a high-fat diet supplemented or not with the PPARγ agonist rosiglitazone (30 mg/kg/day) for 8 weeks and evaluated for iWAT mass, lipidome, transcriptome (Rnaseq), respiration and BCAA metabolism. Adipocyte mTORC1 deficiency not only impaired iWAT adiponectin transcription, synthesis and secretion, PEPCK mRNA levels, triacylglycerol synthesis and BCAA oxidation and mRNA levels of related proteins but also completely blocked the upregulation in these processes induced by pharmacological PPARγ activation with rosiglitazone. Mechanistically, adipocyte mTORC1 deficiency impairs PPARγ transcriptional activity by reducing PPARγ protein content, as well as by downregulating C/EBPα, a co-partner and facilitator of PPARγ. In conclusion, mTORC1 and PPARγ are essential partners involved in the regulation of subcutaneous adipose tissue adiponectin production and secretion and BCAA oxidative metabolism.
Asunto(s)
Adiponectina/metabolismo , Aminoácidos de Cadena Ramificada/metabolismo , Glicerol/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , PPAR gamma/metabolismo , Grasa Subcutánea/metabolismo , Regulación hacia Arriba , Animales , Ratones , Oxidación-ReducciónRESUMEN
SCOPE: Glucose homeostasis and progression of nonalcoholic fatty liver disease (NAFLD) and hepatomegaly in severe lipoatrophic mice and their modulation by intake of a diet rich in omega 3 (n-3) fatty acids (HFO) are evaluated. METHODS AND RESULTS: Severe lipoatrophic mice induced by PPAR-γ deletion exclusively in adipocytes (A-PPARγ KO) and littermate controls (A-PPARγ WT) are evaluated for glucose homeostasis and liver mass, proteomics, lipidomics, inflammation, and fibrosis. Lipoatrophic mice are heavier than controls, severely glucose intolerant, and hyperinsulinemic, and develop NAFLD characterized by increased liver glycogen, triacylglycerol, and diacylglycerol contents, mitotic index, apoptosis, inflammation, steatosis score, fibrosis, and fatty acid synthase (FAS) content and activity. Lipoatrophic mice also display liver enrichment with monounsaturated in detriment of polyunsaturated fatty acids including n-3 fatty acids, and increased content of cardiolipin, a tetracyl phospholipid exclusively found at the mitochondria inner membrane. Administration of a high-fat diet rich in n-3 fatty acids (HFO) to lipoatrophic mice enriches liver with n-3 fatty acids, reduces hepatic steatosis, FAS content and activity, apoptosis, inflammation, and improves glucose homeostasis. CONCLUSION: Diet enrichment with n-3 fatty acids improves glucose homeostasis and reduces liver steatosis and inflammation without affecting hepatomegaly in severe lipoatrophic mice.
Asunto(s)
Ácidos Grasos Omega-3/farmacología , Resistencia a la Insulina , Lipodistrofia/complicaciones , Enfermedad del Hígado Graso no Alcohólico/dietoterapia , Adipocitos/metabolismo , Animales , Dieta Alta en Grasa , Glucosa/metabolismo , Homeostasis/efectos de los fármacos , Masculino , Ratones Noqueados , Ratones Transgénicos , Enfermedad del Hígado Graso no Alcohólico/etiología , Enfermedad del Hígado Graso no Alcohólico/patología , PPAR gamma/genéticaRESUMEN
Palmitoleic acid (POA, 16:1n-7) is a lipokine that has potential nutraceutical use to treat non-alcoholic fatty liver disease. We tested the effects of POA supplementation (daily oral gavage, 300 mg/Kg, 15 days) on murine liver inflammation induced by a high fat diet (HFD, 59% fat, 12 weeks). In HFD-fed mice, POA supplementation reduced serum insulin and improved insulin tolerance compared with oleic acid (OA, 300 mg/Kg). The livers of POA-treated mice exhibited less steatosis and inflammation than those of OA-treated mice with lower inflammatory cytokine levels and reduced toll-like receptor 4 protein content. The anti-inflammatory effects of POA in the liver were accompanied by a reduction in liver macrophages (LM, CD11c+; F4/80+; CD86+), an effect that could be triggered by peroxisome proliferator activated receptor (PPAR)-γ, a lipogenic transcription factor upregulated in livers of POA-treated mice. We also used HFD-fed mice with selective deletion of PPAR-γ in myeloid cells (PPAR-γ KOLyzCre+) to test whether the beneficial anti-inflammatory effects of POA are dependent on macrophages PPAR-γ. POA-mediated improvement of insulin tolerance was tightly dependent on myeloid PPAR-γ, while POA anti-inflammatory actions including the reduction in liver inflammatory cytokines were preserved in mice bearing myeloid cells deficient in PPAR-γ. This overlapped with increased CD206+ (M2a) cells and downregulation of CD86+ and CD11c+ liver macrophages. Moreover, POA supplementation increased hepatic AMPK activity and decreased expression of the fatty acid binding scavenger receptor, CD36. We conclude that POA controls liver inflammation triggered by fat accumulation through induction of M2a macrophages independently of myeloid cell PPAR-γ.
Asunto(s)
Ácidos Grasos Monoinsaturados/farmacología , Inflamación/tratamiento farmacológico , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , PPAR gamma/genética , Quinasas de la Proteína-Quinasa Activada por el AMP , Animales , Antígeno B7-2/genética , Antígeno CD11c/genética , Dieta Alta en Grasa/efectos adversos , Ácidos Grasos Monoinsaturados/metabolismo , Humanos , Inflamación/genética , Inflamación/metabolismo , Inflamación/patología , Resistencia a la Insulina/genética , Lectinas Tipo C/genética , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Receptor de Manosa , Lectinas de Unión a Manosa/genética , Ratones , Células Mieloides/efectos de los fármacos , Células Mieloides/metabolismo , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Ácido Oléico/metabolismo , Ácido Oléico/farmacología , Proteínas Quinasas/genética , Receptores de Superficie Celular/genéticaRESUMEN
Microglial activation by oleate and palmitate differentially modulates brain inflammatory status. However, the metabolic reprogramming supporting these reactive phenotypes remains unknown. Employing real-time metabolic measurements and lipidomic analysis, we show that both fatty acids promote microglial oxidative metabolism, while lipopolysaccharide (LPS) enhances glycolytic rates. Interestingly, oleate treatment was followed by enrichment in storage lipids bound to polyunsaturated fatty acids (PUFA), in parallel with protection against oxidative imbalance. Palmitate, in turn, induced a distinct lipid distribution defined by PUFA linked to membrane phospholipids, which are more susceptible to lipid peroxidation and inflammatory signaling cascades. This distribution was mirrored by LPS treatment, which led to a strong pro-inflammatory phenotype in microglia. Thus, although both oleate and palmitate preserve mitochondrial function, a contrasting lipid distribution supports differences in fatty acid-induced neuroinflammation. These data reinforce the concept that reactive microglial profiles are achieved by stimulus-evoked remodeling in cell metabolism.
Asunto(s)
Encéfalo/patología , Microglía/metabolismo , Mitocondrias/metabolismo , Ácido Oléico/metabolismo , Palmitatos/metabolismo , Animales , Línea Celular , Glucólisis/fisiología , Inflamación/patología , Peroxidación de Lípido/fisiología , Lipopolisacáridos/farmacología , Lípidos de la Membrana/metabolismo , Ratones , Microglía/citología , Neuroinmunomodulación/fisiología , Oxidación-Reducción , Fosforilación OxidativaRESUMEN
SCOPE: The mechanisms and involvement of uncoupling protein 1 (UCP1) in the protection from obesity and insulin resistance induced by intake of a high-fat diet rich in omega-3 (n-3) fatty acids are investigated. METHODS AND RESULTS: C57BL/6J mice are fed either a low-fat (control group) or one of two isocaloric high-fat diets containing either lard (HFD) or fish oil (HFN3) as fat source and evaluated for body weight, adiposity, energy expenditure, glucose homeostasis, and inguinal white and interscapular brown adipose tissue (iWAT and iBAT, respectively) gene expression, lipidome, and mitochondrial bioenergetics. HFN3 intake protected from obesity, glucose and insulin intolerances, and hyperinsulinemia. This is associated with increased energy expenditure, iWAT UCP1 expression, and incorporation of n-3 eicosapentaenoic and docosahexaenoic fatty acids in iWAT and iBAT triacylglycerol. Importantly, HFN3 is equally effective in reducing body weight gain, adiposity, and glucose intolerance and increasing energy expenditure in wild-type and UCP1-deficient mice without recruiting other thermogenic processes in iWAT and iBAT, such as mitochondrial uncoupling and SERCA-mediated calcium and creatine-driven substrate cyclings. CONCLUSION: Intake of a high-fat diet rich in omega-3 fatty acids protects both wild-type and UCP1-deficient mice from obesity and insulin resistance by increasing energy expenditure through unknown mechanisms.
Asunto(s)
Metabolismo Energético/efectos de los fármacos , Aceites de Pescado/farmacología , Intolerancia a la Glucosa/dietoterapia , Obesidad/prevención & control , Proteína Desacopladora 1/genética , Tejido Adiposo Pardo/efectos de los fármacos , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/efectos de los fármacos , Tejido Adiposo Blanco/metabolismo , Animales , Dieta Alta en Grasa/efectos adversos , Metabolismo Energético/genética , Ácidos Grasos Omega-3/análisis , Ácidos Grasos Omega-3/farmacología , Aceites de Pescado/química , Intolerancia a la Glucosa/genética , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/etiología , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/metabolismo , Termogénesis/efectos de los fármacos , Termogénesis/genética , Proteína Desacopladora 1/metabolismoRESUMEN
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by degeneration of upper and lower motor neurons. While the fundamental causes of the disease are still unclear, the accumulation of Cu,Zn-superoxide dismutase (SOD1) immunoreactive aggregates is associated with familial ALS cases. Cholesterol 5,6-secosterol aldehydes (Seco A and Seco B) are reported to contribute to neurodegenerative disease pathology by inducing protein modification and aggregation. Here we have investigated the presence of secosterol aldehydes in ALS SOD1-G93A rats and their capacity to induce SOD1 aggregation. Secosterol aldehydes were analyzed in blood plasma, spinal cord and motor cortex of ALS rats at the pre-symptomatic and symptomatic stages. Seco B was significantly increased in plasma of symptomatic ALS rats compared to pre-symptomatic animals, suggesting an association with disease progression. In vitro experiments showed that both Seco A and Seco B induce the formation of high molecular weight (HMW) SOD1 aggregates with amorphous morphology. SOD1 adduction to ω-alkynyl-secosterols analyzed by click assay showed that modified proteins are only detected in the HMW region, indicating that secosterol adduction generates species highly prone to aggregate. Of note, SOD1-secosterol adducts containing up to five secosterol molecules were confirmed by MALDI-TOF analysis. Interestingly, mass spectrometry sequencing of SOD1 aggregates revealed preferential secosterol adduction to Lys residues located at the electrostatic loop (Lys 122, 128 and 136) and nearby the dimer interface (Lys 3 and 9). Altogether, our results show that secosterol aldehydes are increased in plasma of symptomatic ALS rats and represent a class of aldehydes that can potentially modify SOD1 enhancing its propensity to aggregate.
Asunto(s)
Aldehídos/metabolismo , Esclerosis Amiotrófica Lateral/metabolismo , Colesterol/análogos & derivados , Agregación Patológica de Proteínas/metabolismo , Superóxido Dismutasa-1/metabolismo , Aldehídos/sangre , Esclerosis Amiotrófica Lateral/sangre , Esclerosis Amiotrófica Lateral/genética , Animales , Colesterol/sangre , Colesterol/metabolismo , Modelos Animales de Enfermedad , Humanos , Masculino , Mutación Puntual , Agregado de Proteínas , Agregación Patológica de Proteínas/sangre , Agregación Patológica de Proteínas/genética , Ratas Sprague-Dawley , Ratas Transgénicas , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/ultraestructuraRESUMEN
Uric acid is the final product of purine metabolism in humans and is considered to be quantitatively the main antioxidant in plasma. In vitro studies showed that the oxidation of uric acid by peroxidases, in presence of superoxide, generates urate free radical and urate hydroperoxide. Urate hydroperoxide is a strong oxidant and might be a relevant intermediate in inflammatory conditions. However, the identification of urate hydroperoxide in cells and biological samples has been a challenge due to its high reactivity. By using mass spectrometry, we undoubtedly demonstrated the formation of urate hydroperoxide and its corresponding alcohol, hydroxyisourate during the respiratory burst in peripheral blood neutrophils and in human leukemic cells differentiated in neutrophils (dHL-60). The respiratory burst was induced by phorbol myristate acetate (PMA) and greatly increased oxygen consumption and superoxide production. Both oxygen consumption and superoxide production were further augmented by incubation with uric acid. Conversely, uric acid significantly decreased the levels of HOCl, probably because of the competition with chloride by the catalysis of myeloperoxidase. In spite of the decrease in HOCl, the overall oxidative status, measured by GSH/GSSG ratio, was augmented in the presence of uric acid. In summary, the present results support the formation of urate hydroperoxide, a novel oxidant in neutrophils oxidative burst. Urate hydroperoxide is a strong oxidant and alters the redox balance toward a pro-oxidative environment. The production of urate hydroperoxide in inflammatory conditions could explain, at least in part, the harmful effect associated to uric acid.