RESUMO
Amuc_1100 (hereafter called Amuc) is a highly abundant pili-like protein on the outer membrane of Akkermansia muciniphila and has been found to be effective for in anti-obesity, which is probably through the activation of TLR2. However, the precise mechanisms underlying the contributions of TLR2 to obesity resistance remain unknown. Here, TLR2 knockout mice were used to decipher the anti-obesity mechanism of Amuc. Mice exposed to a high-fat diet (HFD) were treated with Amuc (60 µg) every other day for 8 weeks. The results showed that Amuc supplementation decreased mouse body weight and lipid deposition by regulating fatty acid metabolism and reducing bile acid synthesis by activating TGR5 and FXR and strengthening the intestinal barrier function. The ablation of TLR2 partially reversed the positive effect of Amuc on obesity. Furthermore, we revealed that Amuc altered the gut microbiota composition by increasing the relative abundance of Peptostreptococcaceae, Faecalibaculum, Butyricicoccus, and Mucispirillum_schaedleri_ASF457, and decreasing Desulfovibrionaceae, which may serve as a contributor for Amuc to reinforce the intestinal barrier in HFD-induced mice. Therefore, the anti-obesity effect of Amuc was accompanied by the mitigation of gut microbes. These findings provide support for the use of Amuc as a therapy targeting obesity-associated metabolic syndrome.
Assuntos
Microbioma Gastrointestinal , Síndrome Metabólica , Camundongos , Animais , Dieta Hiperlipídica/efeitos adversos , Receptor 2 Toll-Like , Verrucomicrobia , Obesidade/etiologia , Obesidade/induzido quimicamente , Ácidos Graxos/farmacologia , Ácidos e Sais Biliares/farmacologia , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Obesity, a major public health problem worldwide, is associated with dysfunction of the intestinal barrier. Glycine (Gly) has been reported to enhance the expression of tight-junction proteins in porcine enterocytes. It is unknown whether Gly can improve intestinal barrier integrity in obese mice. OBJECTIVES: This study tested the hypothesis that Gly enhances the intestinal epithelial barrier by regulating endoplasmic reticulum (ER) stress-related signaling and mitigating inflammation in high-fat diet (HFD)-induced obese mice. METHODS: Five-week-old male C57BL/6J mice were fed a normal-fat diet (ND; fat = 10% energy) or an HFD (fat = 60% energy) and received drinking water supplemented with 2% Gly or 2.37% l-alanine (Ala; isonitrogenous control) daily for 12 wk. Body weight gain and tissue weights, glucose tolerance and the activation of immune cells, as well as the abundances of tight-junction proteins, ER stress proteins, and apoptosis-related proteins in the jejunum and colon were determined. In addition, the body weights of naïve ND and HFD groups (nND and nHFD, respectively) were also recorded for comparison. Differences were analyzed statistically by ANOVA followed by the Duncan multiple-comparison test using SAS software. RESULTS: Compared with ND-Ala, HFD-feeding resulted in enhanced macrophage (CD11b+ and F4/80+) infiltration and immune cell activation by 1.9- to 5.4-fold (P < 0.05), as well as the upregulation of ER stress sensor proteins (including phospho-inositol-requiring enzyme 1α and binding immunoglobulin protein) by 2.5- to 4.5-fold, the induction of apoptotic proteins by 1.5- to 3.2-fold, and decreased abundances of tight-junction proteins by 35%-65% (P < 0.05) in the intestine. These HFD-induced abnormalities were significantly ameliorated by Gly supplementation in the HFD-Gly group (P < 0.05). Importantly, Gly supplementation also significantly enhanced glucose tolerance (P < 0.05) by 1.5-fold without affecting the fat accumulation of HFD-induced obese mice. CONCLUSIONS: Gly supplementation enhanced the intestinal barrier and ameliorated inflammation and insulin resistance in HFD-fed mice. These effects of Gly were associated with reduced ER stress-related apoptosis in the intestine of obese mice.
Assuntos
Dieta Hiperlipídica , Microbioma Gastrointestinal , Animais , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Glicina , Inflamação/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/tratamento farmacológico , SuínosRESUMO
BACKGROUND: Excessive white fat accumulation in humans and other animals is associated with the development of multiple metabolic diseases. It is unknown whether dietary L-arginine supplementation reduces lipid deposition in high fat diet-fed Nile tilapia (Oreochromis niloticus). RESULTS: In the present study, we found that dietary supplementation with 1% or 2% arginine decreased the deposition and concentration of fats in the liver; the concentrations of triglycerides, low-density lipoprotein, total cholesterol, and high-density lipoprotein in the serum; and the diameter of adipocytes in intraperitoneal adipose tissue. Compared with the un-supplementation control group, the hepatic activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase, and hepatic concentration of malondialdehyde were reduced but these for catalase and superoxide dismutase were enhanced by dietary supplementation with 2% arginine. Arginine supplementation reduced the total amounts of monounsaturated fatty acids, while increasing the total amounts of n-3 and n-6 polyunsaturated fatty acids in the liver. These effects of arginine were associated with reductions in mRNA levels for genes related to lipogenesis (sterol regulatory element-binding protein-1, acetyl-CoA carboxylase α, stearoyl-CoA desaturase, and fatty acid synthase) but increases in mRNA levels for genes involved in fatty acid ß-oxidation (carnitine palmitoyltransferase 1α and peroxisome proliferator-activated receptor α). In addition, hepatic mRNA levels for Δ4 fatty acyl desaturase 2 and elongase 5 of very long-chain fatty acids were enhanced by arginine supplementation. CONCLUSION: These results revealed that dietary L-arginine supplementation to tilapia reduced high fat diet-induced fat deposition and fatty acid composition in the liver by regulating the expression of genes for lipid metabolism.
RESUMO
Lung diseases affect millions of individuals all over the world. Various environmental factors, such as toxins, chemical pollutants, detergents, viruses, bacteria, microbial dysbiosis, and allergens, contribute to the development of respiratory disorders. Exposure to these factors activates stress responses in host cells and disrupt lung homeostasis, therefore leading to dysfunctional epithelial barriers. Despite significant advances in therapeutic treatments for lung diseases in the last two decades, novel interventional targets are imperative, considering the side effects and limited efficacy in patients treated with currently available drugs. Nutrients, such as amino acids (e.g., arginine, glutamine, glycine, proline, taurine, and tryptophan), peptides, and bioactive molecules, have attracted more and more attention due to their abilities to reduce oxidative stress, inhibit apoptosis, and regulate immune responses, thereby improving epithelial barriers. In this review, we summarize recent advances in amino acid metabolism in the lungs, as well as multifaceted functions of amino acids in attenuating inflammatory lung diseases based on data from studies with both human patients and animal models. The underlying mechanisms for the effects of physiological amino acids are likely complex and involve cell signaling, gene expression, and anti-oxidative reactions. The beneficial effects of amino acids are expected to improve the respiratory health and well-being of humans and other animals. Because viruses (e.g., coronavirus) and environmental pollutants (e.g., PM2.5 particles) induce severe damage to the lungs, it is important to determine whether dietary supplementation or intravenous administration of individual functional amino acids (e.g., arginine-HCl, citrulline, N-acetylcysteine, glutamine, glycine, proline and tryptophan) or their combinations to affected subjects may alleviate injury and dysfunction in this vital organ.
Assuntos
Aminoácidos/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Pneumopatias/metabolismo , Pneumopatias/patologia , Animais , Humanos , Pneumopatias/fisiopatologiaRESUMO
Glycine supplementation has been reported to alleviate lipopolysaccharide (LPS)-induced lung injury in mice. However, the underlying mechanisms responsible for this beneficial effect remain unknown. In the present study, male C57BL/6 mice were treated with aerosolized glycine (1000 mg in 5 mL of 0.9% saline) or vehicle (0.9% saline) once daily for 7 continuous days, and then were exposed to aerosolized LPS (5 mg in 5 mL of 0.9% saline) for 30 min to induce lung injury. Sera and lung tissues were collected 24 h post LPS challenge. Results showed that glycine pretreatment attenuated LPS-induced decreases of mucin at both protein and mRNA levels, reduced LPS-triggered upregulation of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interferons, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukins. Further study showed that glycine-reduced LPS challenge resulted in the upregulation of nuclear factor κB (NF-κB), nucleotide binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome. In addition, LPS exposure led to the downregulation of NRF2 and downstream targets, which were significantly improved by glycine administration in the lung tissues. Our findings indicated that glycine pretreatment prevented LPS-induced lung injury by regulating both NLRP3 inflammasome and NRF2 signaling.
Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Glicina/uso terapêutico , Fator 2 Relacionado a NF-E2/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Transdução de Sinais , Lesão Pulmonar Aguda/sangue , Lesão Pulmonar Aguda/induzido quimicamente , Animais , Autofagia/efeitos dos fármacos , Citocinas/sangue , Regulação para Baixo/efeitos dos fármacos , Glicina/administração & dosagem , Glicina/farmacologia , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Mediadores da Inflamação/sangue , Lipopolissacarídeos , Pulmão/patologia , Masculino , Camundongos Endogâmicos C57BL , Mucinas/metabolismo , NF-kappa B/metabolismoRESUMO
Dietary L-proline (proline) supplementation during gestation enhances fetal survival and placental development in mice. The objective of the present study was to test the hypothesis that this beneficial effect of proline was associated with alterations in inflammatory response at the placenta and fetus interface. Populations of immune cells present in peripheral blood mononuclear cells (PBMC) were determined by flow cytometry analysis. The concentrations of immunoglobulins in plasma, and the concentrations of cytokines in plasma, uterus, placenta, and amniotic fluid were measured using a bead-based immunoassay. The data showed that proline supplementation led to higher (P < 0.05) populations of B lymphocytes (CD3-CD19+), natural killer (NK) cells (CD3-NK1.1+), and dendritic cells (DCs, CD11c+MHCII+) in peripheral blood, as compared with the controls. Conversely, mice fed a proline-supplemented diet had a lower population of neutrophils (CD11b+F4/80-). Further study showed that proline supplementation decreased (P < 0.05) the concentrations of (1) interleukin (IL)-23, IL-1α, and IL-6 in plasma; (2) IL-6 in the uterus; and (3) tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein (MCP)-1, and IL-17 in the placenta; and (4) interferon (IFN)-γ in amniotic fluid, compared with controls. Conversely, proline supplementation resulted in higher (P < 0.05) concentrations of (1) IL-10, IL-17 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in plasma; (2) IL-10 and IL-1α in the uterus; and (3) IL-1α, IL-1ß, IL-10, IL-27, and IFN-ß in amniotic fluid, compared with controls. Moreover, concentrations of immunoglobulin (Ig) G2b and IgM were enhanced (P < 0.05) by proline administration. Taken together, our results reveal a regulatory effect of proline in the immunological response at the maternal-fetal interface, which is critical for embryonic development and fetal survival.
Assuntos
Citocinas/metabolismo , Suplementos Nutricionais , Troca Materno-Fetal/imunologia , Placenta/imunologia , Prolina/fisiologia , Líquido Amniótico/metabolismo , Animais , Citocinas/sangue , Desenvolvimento Embrionário , Feminino , Interleucinas/metabolismo , Leucócitos Mononucleares/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Prolina/administração & dosagem , Fator de Necrose Tumoral alfa/metabolismo , Útero/metabolismoRESUMO
BACKGROUND: Liver dysfunction impairs immunological homeostasis. Glycine (Gly) has been reported to have antioxidative and anti-inflammatory effects and to regulate apoptosis in various models. OBJECTIVES: The aim of the present study was to determine whether Gly could attenuate LPS-induced liver injury. METHODS: In Experiment 1, 48 6-week-old male C57BL/6 mice were randomly assigned into one of 4 groups: CON (control), GLY [orally administered Gly, 5 g · kg body weight (BW)-1 · d-1 for 6 d], LPS (5 mg/kg BW, intraperitoneally administered), and GLY + LPS (Gly supplementation, and on day 7 LPS treatment). In Experiment 2, mice were untreated, pretreated with Gly as above, or pretreated with Gly + l-buthionine sulfoximine (BSO) (0.5 g/kg BW, intraperitoneally administered every other day) for 6 d. On day 7, mice were injected with LPS as above. Histological alterations, activities of antioxidative enzymes, apoptosis, and immune cell infiltration were analyzed. RESULTS: In Experiment 1, compared with CON, LPS administration resulted in increased karyolysis and karyopyknosis in the liver by 8- to 10-fold, enhanced serum activities of alanine transaminase (ALT), aspartate transaminase (AST), and lactate dehydrogenase (LDH) by 1- to 1.8-fold, and increased hepatic apoptosis by 5.5-fold. Furthermore, LPS exposure resulted in increased infiltration of macrophages and neutrophils in the liver by 3.2- to 7.5-fold, elevated hepatic concentrations of malondialdehyde and hydrogen peroxide (H2O2), and elevated myeloperoxidase (MPO) activity by 1.5- to 6.3-fold. In Experiment 2, compared with the LPS group, mice in the GLY + LPS group had fewer histological alterations (68.5%-75.9%); lower serum ALT, AST, and LDH activities (24.3%-64.7%); and lower hepatic malondialdehyde and H2O2 concentrations (46.1%-80.2%), lower MPO activity (39.2%), immune cell infiltration (52.3%-85.3%), and apoptosis (69.6%), which were abrogated by BSO. Compared with the GLY + LPS group, mice in the GLY + BSO + LPS group had lower hepatic activities of catalase, superoxide dismutase, and glutathione peroxidase by 33.5%-48.5%; increased activation of NF-κB by 2.3-fold; and impaired nuclear factor (erythroid-derived 2)-like 2 signaling by 38.9%. CONCLUSIONS: Gly is a functional amino acid with an ability to protect the liver against LPS-induced injury in mice.
Assuntos
Apoptose/efeitos dos fármacos , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Glicina/farmacologia , Inflamação/prevenção & controle , Lipopolissacarídeos/administração & dosagem , Fígado/efeitos dos fármacos , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Doença Hepática Induzida por Substâncias e Drogas/patologia , Peróxido de Hidrogênio/análise , L-Lactato Desidrogenase/sangue , Fígado/química , Macrófagos/patologia , Masculino , Malondialdeído/análise , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/patologia , Peroxidase/metabolismoRESUMO
L-Proline (proline) in amniotic fluid was markedly increased during pregnancy in both pigs and sheep. However, in vivo data to support a beneficial effect of proline on fetal survival are not available. In this study, pregnant C57BL/6J mice were fed a purified diet supplemented with or without 0.50% proline from embryonic day 0.5 (E0.5) to E12.5 or term. Results indicated that dietary supplementation with proline to gestating mice enhanced fetal survival, reproductive performance, the concentrations of proline, arginine, aspartic acid, and tryptophan in plasma and amniotic fluid, while decreasing the concentrations of ammonia and urea in plasma and amniotic fluid. Placental mRNA levels for amino acid transporters, including Slc36a4, Slc38a2, Slc38a4, Slc6a14, and Na+/K+ ATPase subunit-1α (Atp1a1), fatty acid transporter Slc27a4, and glucose transporters Slc2a1 and Slc2a3, were augmented in proline-supplemented mice, compared with the control group. Histological analysis showed that proline supplementation enhanced labyrinth zone in the placenta of mice at E12.5, mRNA levels for Vegf, Vegfr, Nos2, and Nos3, compared with the controls. Western blot analysis showed that proline supplementation increased protein abundances of phosphorylated (p)-mTORC1, p-ribosomal protein S6 kinase (p70S6K), and p-eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), as well as the protein level of GCN2 (a negative regulator of mTORC1 signaling). Collectively, our results indicate a novel functional role of proline in improving placental development and fetal survival by enhancing placental nutrient transport, angiogenesis, and protein synthesis.
Assuntos
Suplementos Nutricionais , Viabilidade Fetal/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Materna , Nutrientes/farmacocinética , Placenta/metabolismo , Placentação/efeitos dos fármacos , Prolina/farmacologia , Sistemas de Transporte de Aminoácidos/metabolismo , Líquido Amniótico/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Embrião de Mamíferos , Feminino , Desenvolvimento Fetal/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Materna/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Placenta/efeitos dos fármacos , GravidezRESUMO
l-Tryptophan (Trp) is known to play an important role in the health of the large intestine. However, a role of dietary Trp in the small-intestinal mucosal barrier and microbiota remains poorly understood. The present study was conducted with weaned piglets to address this issue. Postweaning piglets were fed for 4 weeks a corn- and soybean meal-based diet supplemented with 0 (Control), 0.1, 0.2, or 0.4% Trp. The small-intestinal microbiota and serum amino acids were analyzed by bacterial 16S rRNA gene-based high-throughput sequencing methods and high-performance liquid chromatography, respectively. The mRNA levels for genes involved in host defense and the abundances of tight-junction proteins in jejunum and duodenum were measured by real time-PCR and Western blot techniques, respectively. The concentrations of Trp in the serum of Trp-supplemented piglets increased in a dose-dependent manner. Compared with the control group, dietary supplementation with 0.2â»0.4% Trp reduced the abundances of Clostridium sensu stricto and Streptococcus in the jejunum, increased the abundances of Lactobacillus and Clostridium XI (two species of bacteria that can metabolize Trp) in the jejunum, and augmented the concentrations of secretory immunoglobulin A (sIgA) as well as mRNA levels for porcine ß-defensins 2 and 3 in jejunal tissues. Moreover, dietary Trp supplementation activated the mammalian target of rapamycin signaling and increased the abundances of tight-junction proteins (zonula occludens (ZO)-1, ZO-3, and claudin-1) in jejunum and duodenum. We suggested that Trp-metabolizing bacteria in the small intestine of weaned pigs primarily mediated the beneficial effects of dietary Trp on its mucosal integrity, health, and function.
Assuntos
Suplementos Nutricionais , Mucosa Intestinal/metabolismo , Triptofano/metabolismo , Aminoácidos/sangue , Animais , Animais Recém-Nascidos , Biodiversidade , Microbioma Gastrointestinal , Expressão Gênica , Imunoglobulina A Secretora/biossíntese , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/microbiologia , Permeabilidade , Transdução de Sinais , Suínos , Proteínas de Junções Íntimas/genética , Proteínas de Junções Íntimas/metabolismo , Triptofano/farmacologia , Desmame , beta-Defensinas/genética , beta-Defensinas/metabolismoRESUMO
Glycine supplementation has been reported to enhance white-fat loss and improve sensitivity to insulin in animals with obesity or type 2 diabetes. However, the underlying mechanisms responsible for the beneficial effects of glycine remain largely unknown. The purpose of this study was to test the hypothesis that glycine regulates adipocyte differentiation, adipogenesis, and lipolysis, therefore, contributing to white-fat reduction. 3T3-L1 pre-adipocytes were induced to differentiate into adipocytes in the presence of glycine (0, 0.25, 1.0, and 2.0 mmol/L) or resveratrol (50 or 100 µmol/L, served as a positive control) during the differentiation process. Hela and HepG2 cells cultured with oleic acid to induce lipid accumulation in the presence of glycine (0, 1.0, and 2.0 mmol/L) or 10 µmol/L isoproterenol (served as a positive control) for 24 h. Intracellular lipid accumulation, intracellular triglycerides, lipid droplets' diameters of mature adipocytes, mRNA, and protein levels of genes involved in the adipogenesis and lipolysis were analyzed. Isobutylxanthine-dexamethasone-insulin (MDI)-induced adipogenesis in 3T3-L1 cells were blocked by resveratrol, but not by glycine, as shown by decreased lipid contents, reduced diameters of lipid droplets, decreased protein abundances for peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-enhancer-binding protein α (C/EBPα), as well as increased protein abundance of peroxisome proliferator-activated receptor coactivator-1α (PGC-1α), critical transcriptional factors that regulates adipogenesis. However, the mRNA levels of adiponectin and interleukin-10 (IL-10), two adipose-derived adipocytokines with anti-inflammatory effects, were greatly enhanced (P < 0.05) by 2 mmol/L glycine. Compared with non-treated controls, 10 µmol/L isoproterenol significantly decreased (P < 0.05) the intracellular lipid and triglyceride contents induced by oleic acid in Hela and HepG2 cells. mRNA level of fatty acid synthase (FASN), a gene involved in fatty acid synthesis, was significantly reduced (P < 0.05), while that for ATGL (adipose triglyceride lipase) and HSL (hormone-sensitive lipase), genes involved in lipolysis were significantly enhanced (P < 0.05) by isoproterenol. However, oleic acid induced the accumulation of intracellular triglyceride and lipid contents were not affected by glycine. In conclusion, glycine exposure enhanced the mRNA levels of adipose-derived adiponectin and IL-10 without affecting adipogenesis and lipolysis in 3T3-L1 adipocytes. These findings provide a possible explanation for the anti-obesity and anti-diabetic effects of glycine that were previously reported in animal models. More studies are needed to uncover the underlying mechanisms responsible for this regulatory effect of glycine on anti-inflammatory adipocytokines expression in both in vitro and in vivo models.
Assuntos
Adipócitos/metabolismo , Adipogenia/efeitos dos fármacos , Adiponectina/biossíntese , Regulação da Expressão Gênica/efeitos dos fármacos , Glicina/farmacologia , Interleucina-10/biossíntese , Lipólise/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/citologia , Animais , CamundongosRESUMO
n-3 Long-chain PUFA up-regulate intestinal lipid metabolism. However, whether these metabolic effects of PUFA on intestine are mediated by AMP-activated protein kinase (AMPK) remains to be elucidated. To determine the effects of α-linolenic acid (ALA) on intestinal fatty acid (FA) metabolism and whether these effects were affected by AMPK deletion, mice deficient in the catalytic subunit of AMPKα1 or AMPKα2 and wild-type (WT) mice were fed either a high-fat diet (HF) or HF supplemented with ALA (HF-A). The results showed that ALA supplementation decreased serum TAG content in WT mice. ALA also increased mRNA expression of genes (carnitine palmitoyltransferase 1a, acyl-CoA oxidase 1, medium-chain acyl-CoA dehydrogenase, cytochrome P450 4A10 and pyruvate dehydrogenase kinase isoenzyme 4a) involved in intestinal lipid oxidation and mRNA expression of TAG synthesis-related genes (monoacylglycerol O-acyltransferase 2, diacylglycerol O-acyltransferases 1 and 2) in WT mice. Consistent with these, expression levels of phosphorylated AMPKα1 and AMPKα2 were also increased in WT mice after ALA addition. However, in the absence of either AMPKα1 or AMPKα2, ALA supplementation failed to increase intestinal lipid oxidation. In addition, no significant effects of either diet (HF and HF-A) or genotype (WT, AMPKα1(-/-) and AMPKα2(-/-)) on FA uptake in the intestine and faecal TAG output were observed. Our results suggest that AMPK is indispensable for the effects of ALA on intestinal lipid oxidation.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Indução Enzimática , Mucosa Intestinal/metabolismo , Metabolismo dos Lipídeos , Regulação para Cima , Ácido alfa-Linolênico/uso terapêutico , Proteínas Quinases Ativadas por AMP/genética , Animais , Dieta Hiperlipídica/efeitos adversos , Suplementos Nutricionais , Fezes/química , Hipertrigliceridemia/sangue , Hipertrigliceridemia/etiologia , Hipertrigliceridemia/metabolismo , Hipertrigliceridemia/prevenção & controle , Íleo/enzimologia , Íleo/metabolismo , Mucosa Intestinal/enzimologia , Jejuno/enzimologia , Jejuno/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Processamento de Proteína Pós-Traducional , Triglicerídeos/efeitos adversos , Triglicerídeos/análise , Triglicerídeos/sangue , Triglicerídeos/metabolismoRESUMO
Nonalcoholic fatty liver disease (NAFLD) is now the most common cause of chronic liver disease among children and adolescents in the developed world. Betaine, as a methyl donor, recently has been demonstrated to exert its hepatoprotective effects through rectifying the genomic DNA hypomethylation state. However, whether betaine supplementation affects N6-methyladenosine (m(6)A) mRNA methylation in NAFLD is still unknown. We conducted the current study to investigate the effects of betaine supplementation during adolescence on high-fat diet-induced pathological changes in liver of mice, and we further identified the effects of betaine supplementation on expression of the fat mass and obesity-associated gene (FTO) and hepatic m(6)A mRNA methylation. Our results showed that betaine supplementation across adolescence significantly alleviated high-fat-induced impairment of liver function and morphology as well as ectopic fat accumulation. Surprisingly, no significant effects on serum TG and NEFA level, as well as fat mass, were observed in mice supplemented with betaine. We also found that high-fat diet upregulated ACC1 and FAS gene expression and downregulated HSL and ATGL gene expression. However, these alterations were rectified by betaine supplementation. Moreover, an m(6)A hypomethylation state and increased FTO expression were detected in mice fed with high-fat diet, while betaine supplementation prevented these changes. Our results suggested that betaine supplementation during adolescence could protect mice from high-fat-induced NAFLD by decreasing de novo lipogenesis and increasing lipolysis. Furthermore, a novel FTO-dependent function of m(6)A may involve in the hepatoprotective effects of betaine.
Assuntos
Betaína/farmacologia , Oxigenases de Função Mista/fisiologia , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Oxo-Ácido-Liases/fisiologia , Adenosina/análogos & derivados , Adenosina/metabolismo , Dioxigenase FTO Dependente de alfa-Cetoglutarato , Animais , Betaína/uso terapêutico , Glicemia , Colesterol/sangue , Citoproteção , Dieta Hiperlipídica/efeitos adversos , Avaliação Pré-Clínica de Medicamentos , Feminino , Expressão Gênica/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/patologia , Metilação , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Processamento Pós-Transcricional do RNA , RNA Mensageiro/metabolismo , Aumento de Peso/efeitos dos fármacosRESUMO
Selenium-enriched exopolysaccharides (EPS) produced by Enterobacter cloacae Z0206 have been proven to possess effect on reducing blood glucose level in diabetic mice. To investigate the specific mechanism, we studied the effects of oral supply with EPS on skeletal muscle glucose transportation and consumption in high-fat-diet-induced diabetic KKAy mice. We found that EPS supplementation increased expressions of glucose transporter 4 (Glut4), hexokinase 2 (hk2), phosphorylation of AMP-activated kinase subunit α2 (pAMPKα2), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and increased expression of characteristic protein of oxidative fibers such as troponin I and cytochrome c (Cytc). Furthermore, we found that EPS increased glucose uptake and expressions of pAMPKα2 and PGC-1α in palmitic acid (PA)-induced C2C12 cells. However, while EPS inhibited AMPKα2 with interference RNA (iRNA), effects of EPS on the improvement of glucose uptake diminished. These results indicated that EPS may improve skeletal muscle glucose uptake of diabetic KKAy mice through AMPKα2-PGC-1α pathway
Assuntos
Animais , Camundongos , Diabetes Mellitus Experimental/fisiopatologia , Polissacarídeos/farmacocinética , Selênio/farmacocinética , Hipoglicemiantes/farmacocinética , Glucose/metabolismo , Enterobacter cloacae/metabolismo , Músculo EsqueléticoRESUMO
Selenium-enriched exopolysaccharides (EPS) produced by Enterobacter cloacae Z0206 have been proven to possess effect on reducing blood glucose level in diabetic mice. To investigate the specific mechanism, we studied the effects of oral supply with EPS on skeletal muscle glucose transportation and consumption in high-fat-diet-induced diabetic KKAy mice. We found that EPS supplementation increased expressions of glucose transporter 4 (Glut4), hexokinase 2 (hk2), phosphorylation of AMP-activated kinase subunit α2 (pAMPKα2), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and increased expression of characteristic protein of oxidative fibers such as troponin I and cytochrome c (Cytc). Furthermore, we found that EPS increased glucose uptake and expressions of pAMPKα2 and PGC-1α in palmitic acid (PA)-induced C2C12 cells. However, while EPS inhibited AMPKα2 with interference RNA (iRNA), effects of EPS on the improvement of glucose uptake diminished. These results indicated that EPS may improve skeletal muscle glucose uptake of diabetic KKAy mice through AMPKα2-PGC-1α pathway.
Assuntos
Adenilato Quinase/metabolismo , Glucose/metabolismo , Músculo Esquelético/efeitos dos fármacos , Polissacarídeos/farmacologia , Selênio/administração & dosagem , Animais , Linhagem Celular , Meios de Cultura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/metabolismo , Polissacarídeos/administração & dosagem , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Polysaccharides belong to a structurally diverse class of macromolecules, with the necessary flexibility for the precise regulatory mechanisms and high capacity for carrying biological information. On the basis of a previous study regarding the administration of selenium-enriched exopolysaccharides (Se-ECZ-EPS) produced by Enterobacter cloacae (E. cloacae) Z0206 which resulted in a reduction of blood glucose levels and showed significant anti-inflammatory and anti-diabetic effects, the present study was conducted to evaluate the effects and mechanism of EPS on the alleviation of fat inflammation in high-fat-diet (HFD) induced-diabetic KKAy mice. The HFD induced-diabetic KKAy mice were gavaged once daily with EPS (0.2 mg/g body weight) or distilled water, while the C57BL/6J mice were gavaged with distilled water. Six weeks later visceral adipose tissue (VAT) was collected for quantified polymerase chain reaction (qPCR) and western blot (WB) analysis. The results showed that following supplementation with EPS, interleukin (IL) 6, IL1ß and tumor necrosis factor (TNF) α mRNA expression in VAT were significantly reduced, while Glut4, pAMPK and SirT1 protein expression were markedly increased when compared with KKAy mice gavaged with water. Furthermore, ATGL and HSL mRNA were also significantly decreased. Subsequently, 3T3-L1 adipocytes were treated with insulin to induce insulin resistance to determine the mechanism by which EPS affects inflammation. Following the treatment of adipocytes with 100 nM insulin for 8 h, IL6 and TNFα mRNA expression were significantly increased, while the content of glucose uptake and Glut4 protein expression were significantly decreased. When treated with 100 nM insulin and 0.1 mg/ml EPS, no significant change in IL6 and TNFα mRNA expression or glucose uptake were observed. However, when SirT1siRNA or AMPKα1-siRNA was transfected into the 3T3-L1 adipocytes prior to treatment with insulin and EPS, there was a significant increase in IL6 and TNFα mRNA abundance. In conclusion, VAT inflammation and lipolysis in HFD-induced KKAy mice were significantly decreased following EPS usage. Moreover, EPS may alleviate VAT inflammation primarily through the AMPK/SirT1 pathway.