RESUMO
Obesity causes systemic inflammation, hepatic and renal damage, as well as gut microbiota dysbiosis. Alternative vegetable sources rich in polyphenols are known to prevent or delay the progression of metabolic abnormalities during obesity. Vachellia farnesiana (VF) is a potent source of polyphenols with antioxidant and anti-inflammatory activities with potential anti-obesity effects. We performed an in vivo preventive or an interventional experimental study in mice and in vitro experiments with different cell types. In the preventive study, male C57BL/6 mice were fed with a Control diet, a high-fat diet, or a high-fat diet containing either 0.1% methyl gallate, 10% powdered VFP, or 0.5%, 1%, or 2% of a polyphenolic extract (PE) derived from VFP (Vachellia farnesiana pods) for 14 weeks. In the intervention study, two groups of mice were fed for 14 weeks with a high-fat diet and then one switched to a high-fat diet with 10% powdered VFP for ten additional weeks. In the in vitro studies, we evaluated the effect of a VFPE (Vachellia farnesiana polyphenolic extract) on glucose-stimulated insulin secretion in INS-1E cells or of naringenin or methyl gallate on mitochondrial activity in primary hepatocytes and C2C12 myotubes. VFP or a VFPE increased whole-body energy expenditure and mitochondrial activity in skeletal muscle; prevented insulin resistance, hepatic steatosis, and kidney damage; exerted immunomodulatory effects; and reshaped fecal gut microbiota composition in mice fed a high-fat diet. VFPE decreased insulin secretion in INS-1E cells, and its isolated compounds naringenin and methyl gallate increased mitochondrial activity in primary hepatocytes and C2C12 myotubes. In conclusion VFP or a VFPE prevented systemic inflammation, insulin resistance, and hepatic and renal damage in mice fed a high-fat diet associated with increased energy expenditure, improved mitochondrial function, and reduction in insulin secretion.
Assuntos
Dieta Hiperlipídica , Resistência à Insulina , Masculino , Animais , Camundongos , Dieta Hiperlipídica/efeitos adversos , Prebióticos , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Extratos Vegetais/farmacologia , Inflamação/tratamento farmacológicoRESUMO
SIRT1 is an NAD+-dependent class III histone deacetylase that is abundantly expressed in the kidney, where it modulates gene expression, apoptosis, energy homeostasis, autophagy, acute stress responses, and mitochondrial biogenesis. Alterations in SIRT1 activity and NAD+ metabolism are frequently observed in acute and chronic kidney diseases of diverse origins, including obesity and diabetes. Nevertheless, in vitro and in vivo studies and clinical trials with humans show that the SIRT1-activating compounds derived from natural sources, such as polyphenols found in fruits, vegetables, and plants, including resveratrol, quercetin, and isoflavones, can prevent disease and be part of treatments for a wide variety of diseases. Here, we summarize the roles of SIRT1 and NAD+ metabolism in renal pathophysiology and provide an overview of polyphenols that have the potential to restore SIRT1 and NAD+ metabolism in renal diseases.
Assuntos
Nefropatias , Sirtuína 1 , Humanos , Rim/metabolismo , Nefropatias/tratamento farmacológico , Nefropatias/metabolismo , NAD/metabolismo , Polifenóis/farmacologia , Sirtuína 1/metabolismoRESUMO
BACKGROUND AND AIM: Circulating amino acids are modified by sex, body mass index (BMI) and insulin resistance (IR). However, whether the presence of genetic variants in branched-chain amino acid (BCAA) catabolic enzymes modifies circulating amino acids is still unknown. Thus, we determined the frequency of two genetic variants, one in the branched-chain aminotransferase 2 (BCAT2) gene (rs11548193), and one in the branched-chain ketoacid dehydrogenase (BCKDH) gene (rs45500792), and elucidated their impact on circulating amino acid levels together with clinical, anthropometric and biochemical parameters. METHODS AND RESULTS: We performed a cross-sectional comparative study in which we recruited 1612 young adults (749 women and 863 men) aged 19.7 ± 2.1 years and with a BMI of 24.9 ± 4.7 kg/m2. Participants underwent clinical evaluation and provided blood samples for DNA extraction and biochemical analysis. The single nucleotide polymorphisms (SNPs) were determined by allelic discrimination using real-time polymerase chain reaction (PCR). The frequencies of the less common alleles were 15.2 % for BCAT2 and 9.83 % for BCKDH. The subjects with either the BCAT2 or BCKDH SNPs displayed no differences in the evaluated parameters compared with subjects homozygotes for the most common allele at each SNP. However, subjects with both SNPs had higher body weight, BMI, blood pressure, glucose, and circulating levels of aspartate, isoleucine, methionine, and proline than the subjects homozygotes for the most common allele (P < 0.05, One-way ANOVA). CONCLUSION: Our findings suggest that the joint presence of both the BCAT2 rs11548193 and BCKDH rs45500792 SNPs induces metabolic alterations that are not observed in subjects without either SNP.
Assuntos
3-Metil-2-Oxobutanoato Desidrogenase (Lipoamida)/genética , Aminoácidos/sangue , Antígenos de Histocompatibilidade Menor/genética , Polimorfismo de Nucleotídeo Único , Proteínas da Gravidez/genética , Transaminases/genética , 3-Metil-2-Oxobutanoato Desidrogenase (Lipoamida)/metabolismo , Adolescente , Fatores Etários , Biomarcadores/sangue , Glicemia/análise , Pressão Sanguínea , Índice de Massa Corporal , Estudos Transversais , Feminino , Frequência do Gene , Estudos de Associação Genética , Homozigoto , Humanos , Masculino , México , Antígenos de Histocompatibilidade Menor/metabolismo , Fenótipo , Proteínas da Gravidez/metabolismo , Transaminases/metabolismo , Adulto JovemRESUMO
BACKGROUND: Swietenia humilis seeds are consumed in Mexico to treat type 2 diabetes; the antihyperglycemic effect of this species was previously demonstrated and related to the presence of tetranortriterpenoids of the mexicanolide class. PURPOSE AND STUDY DESIGN: The present investigation was conducted to determine the mechanism of action of selected mexicanolides, including 2-hydroxy-destigloyl-6-deoxyswietenine acetate (1), methyl-2-hydroxy-3-ß-tigloyloxy-1-oxomeliac-8(30)-enate (2) and humilinolide H (3), using in vivo experiments with hyperglycemic mice, and cell-based models. METHODS: Nicotinamide-streptozotocin hyperglycemic mice (50-130â¯mg/kg, i.p.) were used to build antihyperglycemic drug-response curves using an oral glucose tolerance test model. In vitro studies were carried out on INSE1, H4IIE and C2C12 cells to assess insulin secretion, glucose-6-phosphatase inhibition, glucose uptake and mitochondrial bioenergetics, respectively. RESULTS: The combination of the decoction of S. humilis or 2-hydroxy-destigloyl-6-deoxyswietenine acetate (mexicanolide 1) with glibenclamide resulted in a reduction of the antihyperglycemic effect while a significant increase was observed when they were dosed with metformin. These effects were related to KATP SUR blockade, insulin secretion in INSE1 cells, and modulation of 5-HT2 receptors. Furthermore, mexicanolides 1-3 inhibited glucose-phosphatase in H4IIE cells, and enhanced glucose uptake and spare respiratory capacity in C2C12 myotubes. CONCLUSION: S. humilis mexicanolides interact with pharmacological targets at pancreas (KATP channels), liver (glucose-6-phosphatase), and skeletal muscle (mitochondria and possibly glucose transporters) to modulate glucose homeostasis, and could be a promising resource to treat type 2 diabetes.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/farmacologia , Limoninas/farmacologia , Meliaceae/química , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Teste de Tolerância a Glucose , Glibureto/farmacologia , Hipoglicemiantes/administração & dosagem , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Metformina/farmacologia , México , Camundongos Endogâmicos ICR , Pâncreas/efeitos dos fármacos , Pâncreas/metabolismo , Plantas Medicinais/químicaRESUMO
The STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) controls the activity of the electroneutral cation-chloride cotransporters (SLC12 family) and thus physiological processes such as modulation of cell volume, intracellular chloride concentration [Cl-]i, and transepithelial salt transport. Modulation of SPAK kinase activity may have an impact on hypertension and obesity, as STK39, the gene encoding SPAK, has been suggested as a hypertension and obesity susceptibility gene. In fact, the absence of SPAK activity in mice in which the activating threonine in the T loop was substituted by alanine (SPAK-KI mice) is associated with decreased blood pressure; however its consequences in metabolism have not been explored. Here, we fed wild-type and homozygous SPAK-KI mice a high-fat diet for 17 wk to evaluate weight gain, circulating substrates and hormones, energy expenditure, glucose tolerance, and insulin sensitivity. SPAK-KI mice exhibit resistance to HFD-induced obesity and hepatic steatosis associated with increased energy expenditure, higher thermogenic activity in brown adipose tissue, increased mitochondrial activity in skeletal muscle, and reduced white adipose tissue hypertrophy mediated by augmented whole body insulin sensitivity and glucose tolerance. Our data reveal a previously unrecognized role for the SPAK kinase in the regulation of energy balance, thermogenesis, and insulin sensitivity, suggesting that this kinase could be a new drug target for the treatment of obesity and the metabolic syndrome.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/genética , Resistência à Insulina/genética , Proteínas Serina-Treonina Quinases/genética , Aumento de Peso/genética , Animais , Células Cultivadas , Gorduras na Dieta/farmacologia , Metabolismo Energético/efeitos dos fármacos , Técnicas de Introdução de Genes , Inativação Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Serina-Treonina Quinases/fisiologia , Aumento de Peso/efeitos dos fármacosRESUMO
SCOPE: Hyperglucagonemia contributes to hyperglycemia in type 2 diabetes (T2D). Previously, we have found that soy protein normalized fasting hyperglucagonemia in obese Zucker (fa/fa) rats, sensitizing the HSL-lipolytic signaling pathway in white adipose tissue (WAT), however the mechanism remains unknown. METHODS AND RESULTS: Zucker (fa/fa) rats were fed casein or soy protein diet in combination with soybean or coconut oil. Glucagon receptor (GR) was increased at the plasma membrane of adipocytes of rats fed soy protein compared to those fed casein, without changes in total GR abundance. The protein abundance of Rab4, a GTPase involved in GR fast recycling, was dramatically up-regulated in adipocytes of rats fed soy protein. The proportion of GR bound to Rab4 or to RAMP2, involved in promoting GR ligand-binding and G protein selectivity, increased when soy protein was combined with soybean oil as fat source. In rats fed soy protein with coconut oil, Rab11 levels, a protein involved in the slow recycling of GR, was also increased. CONCLUSION: Soy protein increases GR recycling to the membrane of adipocytes and its ligand-binding and G protein selectivity, suggesting, it could be used in T2D dietary treatment to reestablish glucagon sensitivity in WAT, leading to the regulation of circulating glucagon levels.
Assuntos
Adipócitos/efeitos dos fármacos , Glucagon/sangue , Obesidade/sangue , Receptores de Glucagon/metabolismo , Proteínas de Soja/farmacologia , Adipócitos/metabolismo , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Animais , Membrana Celular/metabolismo , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dieta , Modelos Animais de Doenças , Regulação da Expressão Gênica , Hiperglicemia/sangue , Hiperglicemia/tratamento farmacológico , Masculino , Obesidade/tratamento farmacológico , Ratos , Ratos Zucker , Receptores de Glucagon/genética , Triglicerídeos/sangue , Proteínas rab de Ligação ao GTP/genética , Proteínas rab de Ligação ao GTP/metabolismoRESUMO
Long-term dietary and pharmacological treatments for obesity have been questioned, particularly in individuals with severe obesity, so a new approach may involve adipose tissue transplants, particularly autologous transplants. Thus, the aim of this study was to evaluate the metabolic effects of autologous subcutaneous adipose tissue (SAT) transplants into two specific intraabdominal cavity sites (omental and retroperitoneal) after 90 days. The study was performed using two different diet-induced obesity (DIO) rat models: one using a high-fat diet (HFD) and the other using a high-carbohydrate diet (HCHD). Autologous SAT transplant reduced hypertrophic adipocytes, improved insulin sensitivity, reduced hepatic lipid content, and fasting serum-free fatty acids (FFAs) concentrations in the two DIO models. In addition, the reductions in FFAs and glycerol were accompanied by a greater reduction in lipolysis, assessed via the phosphorylation status of HSL, in the transplanted adipose tissue localized in the omentum compared with that localized in the retroperitoneal compartment. Therefore, the improvement in hepatic lipid content after autologous SAT transplant may be partially attributed to a reduction in lipolysis in the transplanted adipose tissue in the omentum due to the direct drainage of FFAs into the liver. The HCHD resulted in elevated fasting and postprandial serum insulin levels, which were dramatically reduced by the autologous SAT transplant. In conclusion, the specific intraabdominal localization of the autologous SAT transplant improved the carbohydrate and lipid metabolism of adipose tissue in obese rats and selectively corrected the metabolic parameters that are dependent on the type of diet used to generate the DIO model.
Assuntos
Tecido Adiposo/metabolismo , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/metabolismo , Resistência à Insulina/fisiologia , Fígado/metabolismo , Obesidade/metabolismo , Gordura Subcutânea/transplante , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Autoenxertos , Dieta da Carga de Carboidratos/efeitos adversos , Dieta da Carga de Carboidratos/métodos , Dieta Hiperlipídica/métodos , Ácidos Graxos não Esterificados/sangue , Insulina/sangue , Metabolismo dos Lipídeos , Fígado/patologia , Masculino , Obesidade/etiologia , Obesidade/cirurgia , Ratos , Ratos WistarRESUMO
BACKGROUND AND AIMS: Dietary fat plays a central role in the development of obesity. However, the metabolic consequences of dietary fat can vary depending on their fatty acid composition. Therefore, the aim of the present work was to study the effect of the type and amount of dietary fat on the expression of genes controlling lipogenesis and fatty acid oxidation in the liver or adipose tissue of rats. METHODS: The expression of hepatic or adipose tissue lipid metabolic genes from Sprague Dawley or Zucker(fa/fa) rats, respectively, was measured after chronic consumption of diets containing different types/amounts of dietary fats or after rats were adapted for 2 months to a high-fat Western diet and then fed different types and amounts of fats. RESULTS: Each fat or oil in the diet regulated differentially the expression of transcription factors involved in lipogenesis and fatty acid oxidation as well as some of its target genes in liver. The expression of these genes after a chronic consumption of a high-fat Western diet was reestablished in the presence of less dietary fat and was dependent on the type of fat. In obese Zucker(fa/fa) rats, consumption of a high-fat diet repressed the expression of lipogenic, fatty acid oxidation and thermogenic genes in adipose tissue. CONCLUSIONS: Type of fat influences the expression of genes that are involved in lipid metabolism in liver and adipose tissue, but this response is repressed when the amount of dietary fat is excessive, diminishing the differences between each type of fat.
Assuntos
Tecido Adiposo/metabolismo , Gorduras na Dieta/administração & dosagem , Expressão Gênica , Metabolismo dos Lipídeos/genética , Fígado/metabolismo , Animais , Gorduras na Dieta/metabolismo , Ratos , Ratos Sprague-Dawley , Ratos Zucker , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Obesity is a risk factor for the development of chronic kidney disease (CKD) and end-stage renal disease. It is not clear whether the adoption of a high-protein diet in obese patients affects renal lipid metabolism or kidney function. Thus the aims of this study were to assess in obese Zuckerfa/fa rats the effects of different types and amounts of dietary protein on the expression of lipogenic and inflammatory genes, as well as renal lipid concentration and biochemical parameters of kidney function. Rats were fed different concentrations of soy protein or casein (20, 30, 45%) for 2 mo. Independent of the type of protein ingested, higher dietary protein intake led to higher serum triglycerides (TG) than rats fed adequate concentrations of protein. Additionally, the soy protein diet significantly increased serum TG compared with the casein diet. However, rats fed soy protein had significantly decreased serum cholesterol concentrations compared with those fed a casein diet. No significant differences in renal TG and cholesterol concentrations were observed between rats fed with either protein diets. Renal expression of sterol-regulatory element binding protein 2 (SREBP-2) and its target gene HMG-CoA reductase was significantly increased as the concentration of dietary protein increased. The highest protein diets were associated with greater expression of proinflammatory cytokines in the kidney, independent of the type of dietary protein. These results indicate that high soy or casein protein diets upregulate the expression of lipogenic and proinflammatory genes in the kidney.
Assuntos
Caseínas/administração & dosagem , Proteínas Alimentares/administração & dosagem , Rim/fisiologia , Obesidade/metabolismo , Proteínas de Soja/administração & dosagem , Animais , Glicemia/metabolismo , Caseínas/farmacologia , Colesterol/sangue , Colágeno Tipo IV/biossíntese , Proteínas Alimentares/farmacologia , Peróxido de Hidrogênio/urina , Hidroximetilglutaril-CoA Redutases/biossíntese , Insulina/sangue , Interleucina-6/biossíntese , Rim/anatomia & histologia , Rim/efeitos dos fármacos , Lipogênese , Tamanho do Órgão , Estresse Oxidativo , Ratos , Ratos Zucker , Proteínas de Soja/farmacologia , Proteína de Ligação a Elemento Regulador de Esterol 1/biossíntese , Proteína de Ligação a Elemento Regulador de Esterol 2/biossíntese , Fator de Crescimento Transformador beta/biossíntese , Triglicerídeos/sangue , Fator de Necrose Tumoral alfa/biossínteseRESUMO
The mammalian kidney bumetanide-sensitive Na(+)-K(+)-2Cl(-) and thiazide-sensitive Na(+)-Cl(-) cotransporters are the major pathways for salt reabsorption in the thick ascending limb of Henle's loop and distal convoluted tubule, respectively. These cotransporters serve as receptors for the loop- and thiazide-type diuretics, and inactivating mutations of corresponding genes are associated with development of Bartter's syndrome type I and Gitleman's disease, respectively. Structural requirements for ion translocation and diuretic binding specificity are unknown. As an initial approach for analyzing structural determinants conferring ion or diuretic preferences in these cotransporters, we exploited functional differences and structural similarities between Na(+)-K(+)-2Cl(-) and Na(+)-Cl(-) cotransporters to design and study chimeric proteins in which the NH(2)-terminal and/or COOH-terminal domains were switched between each other. Thus six chimeric proteins were produced. Using the heterologous expression system of Xenopus laevis oocytes, we observed that four chimeras exhibited functional activity. Our results revealed that, in the Na(+)-K(+)-2Cl(-) cotransporter, ion translocation and diuretic binding specificity are determined by the central hydrophobic domain. Thus NH(2)-terminal and COOH-terminal domains do not play a role in defining these properties. A similar conclusion can be suggested for the Na(+)-Cl(-) cotransporter.
Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Alça do Néfron/metabolismo , Receptores de Droga/genética , Receptores de Droga/metabolismo , Simportadores de Cloreto de Sódio-Potássio/genética , Simportadores de Cloreto de Sódio-Potássio/metabolismo , Simportadores , Animais , Benzotiadiazinas , Bumetanida/farmacologia , Proteínas de Transporte/química , Polaridade Celular/fisiologia , Clonagem Molecular , Diuréticos/farmacologia , Feminino , Mutagênese , Oócitos , Estrutura Terciária de Proteína , Ratos , Receptores de Droga/química , Proteínas Recombinantes de Fusão/metabolismo , Inibidores de Simportadores de Cloreto de Sódio/farmacologia , Simportadores de Cloreto de Sódio , Simportadores de Cloreto de Sódio-Potássio/química , Membro 1 da Família 12 de Carreador de Soluto , Membro 3 da Família 12 de Carreador de Soluto , Xenopus laevisRESUMO
The thiazide-sensitive Na+:Cl- cotransporter is the major salt transport pathway in the distal convoluted tubule of the kidney, and a role of this cotransporter in blood pressure homeostasis has been defined by physiological studies on pressure natriuresis and by its involvement in monogenic diseases that feature arterial hypotension or hypertension. Data base analysis revealed that 135 single nucleotide polymorphisms along the human SLC12A3 gene that encodes the Na+:Cl- cotransporter have been reported. Eight are located within the coding region, and one results in a single amino acid change; the residue glycine at the position 264 is changed to alanine (G264A). This residue is located within the fourth transmembrane domain of the predicted structure. Because Gly-264 is a highly conserved residue, we studied the functional properties of this polymorphism by using in vitro mutagenesis and the heterologous expression system in Xenopus laevis oocytes. G264A resulted in a significant and reproducible reduction ( approximately 50%) in (22)Na+ uptake when compared with the wild type cotransporter. The affinity for extracellular Cl- and for thiazide diuretics was increased in G264A. Western blot analysis showed similar immunoreactive bands between the wild type and the G264A cotransporters, and confocal images of oocytes injected with enhanced green fluorescent protein-tagged wild type and G264A cotransporter showed no differences in the protein surface expression level. These observations suggest that the G264A polymorphism is associated with reduction in the substrate translocation rate of the cotransporter, due to a decrease in the intrinsic activity. Our study also reveals a role of the transmembrane segment 4 in defining the affinity for extracellular Cl- and thiazide diuretics.