Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 187
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Theriogenology ; 141: 54-61, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31518729

RESUMO

The concentration of fatty acids in follicular fluid reflect the physical condition of donors, and palmitic acid (PA) is a major component of follicular fluid. The present study examined the effect of PA on in vitro oocyte growth and investigated the molecular backgrounds of the PA induced-low quality oocytes. Oocyte-granulosa cell complexes (OGCs) were collected from early antral follicles of gilts. The OGCs were cultured for 14 days in a medium containing 0.5 mM PA or vehicle (BSA). PA was found to reduce granulosa cell (GCs) proliferation (0.73 fold) and viability (93.9% vs. 85.8%) and increase lipid content in oocytes and GCs. Oocytes developed in the presence of PA had low developmental ability to the blastocyst stage. In addition, PA affected developmental and epigenetic markers of histone modifications in oocytes; levels of H4K12 acetylation and H3K9 demethylation. PA affected cellular proliferation, apoptosis and endoplasmic reticulum stress markers along with reducing the phosphor-AKT/AKT levels and increasing the expression levels of caspase-3 and CHOP in GCs. Incubation of OGCs with PA increased ceramide content in the GC, and addition of ceramide to the culture medium inhibited GC proliferation. In conclusion, it is suggested that high PA content in the medium reduces viability and proliferation through ceramide accumulation, and PA impaires the developmental ability of oocytes grown in vitro. In addition, high-fat conditions induce changes in the histone modifications of oocytes grown in vitro.


Assuntos
Células da Granulosa/fisiologia , Técnicas de Maturação in Vitro de Oócitos/veterinária , Oócitos/fisiologia , Ácido Palmítico/toxicidade , Suínos , Animais , Apoptose , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Retículo Endoplasmático , Feminino
2.
Int J Med Sci ; 16(12): 1593-1603, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839747

RESUMO

Background: Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, and its pathogenesis and mechanism are intricate. In the present study, we aimed to evaluate the role of PPAR δ in LPS associated NAFLD and to investigate the signal transduction pathways underlying PPAR δ treatment in vitro. Material and Methods: L02 cells were exposed to palmitic acid (PA) and/or LPS in the absence or presence of PPAR δ inhibition and/or activation. Results: LPS treatment markedly increased lipid deposition, FFA contents, IL-6 and TNF-α levels, and cell apoptosis in PA treatment (NAFLD model). PPAR δ inhibition protects L02 cells against LPS-induced lipidosis and injury. Conversely, the result of PPAR δ activation showed the reverse trend. LPS+PA treatment group significantly decreases the relative expression level of IRS-1, PI3K, AKT, phosphorylation of AKT, TLR-4, MyD88, phosphorylation of IKKα, NF-κB, Bcl-2 and increases the relative expression level of Bax, cleaved caspase 3 and cleaved caspase 8, compared with the cells treated with NAFLD model. PPAR δ inhibition upregulated the related proteins' expression level in insulin resistance and inflammation pathway and downregulated apoptotic relevant proteins. Instead, PPAR δ agonist showed the reverse trend. Conclusion: Our data show that PPAR δ inhibition reduces steatosis, inflammation and apoptosis in LPS-related NAFLD damage, in vitro. PPAR δ may be a potential therapeutic implication for NAFLD.


Assuntos
Fígado Gorduroso/tratamento farmacológico , Lipidoses/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , PPAR delta/genética , Substâncias Protetoras/farmacologia , Apoptose/efeitos dos fármacos , Células Cultivadas , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Hepatócitos/efeitos dos fármacos , Humanos , Lipidoses/genética , Lipidoses/metabolismo , Lipidoses/patologia , Lipídeos/genética , Lipopolissacarídeos/toxicidade , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , PPAR delta/agonistas , PPAR delta/antagonistas & inibidores , Ácido Palmítico/toxicidade , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/farmacologia , Transdução de Sinais/efeitos dos fármacos , Tiazóis/farmacologia
3.
Int J Mol Sci ; 20(23)2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31771123

RESUMO

Equine metabolic syndrome (EMS) is a cluster of metabolic disorders, such as obesity, hyperinsulinemia, and hyperleptinemia, as well as insulin resistance (IR). In accordance with the theory linking obesity and IR, excessive accumulation of lipids in insulin-sensitive tissues (lipotoxicity), like liver, alters several cellular functions, including insulin signaling. Therefore, the purpose of the study was to isolate equine hepatic progenitor-like cells (HPCs) and assess whether inhibition of low molecular weight protein tyrosine phosphatase (LMPTP) affects the expression of genes involved in macroautophagy, chaperone-mediated autophagy (CMA), endoplasmic reticulum stress, and mitochondrial dynamics in a palmitate-induced IR model. We demonstrated that LMPTP inhibition significantly enhanced expression of heat shock cognate 70 kDa protein (HSC70), lysosome-associated membrane protein 2 (LAMP2), and parkin (PRKN), all master regulators of selective autophagy. We also observed downregulation of C/EBP homologous protein (CHOP), activating transcription factor 6 (ATF6) and binding immunoglobulin protein encoded by the HSPA gene. Moreover, LMPTP inhibition increased alternative splicing of X-box binding protein 1 (XBP1), suggesting high endonuclease activity of inositol-requiring enzyme 1 alpha (IRE1α). Taken together, our data provide convincing evidence that LMPTP inhibition reverses palmitate-induced insulin resistance and lipotoxicity. In conclusion, this study highlights the role of LMPTP in the regulation of CMA, mitophagy, and ER stress, and provides a new in vitro model for studying HPC lipotoxicity in pre-clinical research.


Assuntos
Morte Celular Autofágica , Estresse do Retículo Endoplasmático , Doenças dos Cavalos/enzimologia , Fígado/enzimologia , Síndrome Metabólica/enzimologia , Proteínas Tirosina Fosfatases/metabolismo , Células-Tronco/enzimologia , Animais , Doenças dos Cavalos/patologia , Cavalos , Resistência à Insulina , Fígado/patologia , Síndrome Metabólica/patologia , Ácido Palmítico/toxicidade , Células-Tronco/patologia
5.
Med Sci Monit ; 25: 7702-7708, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31607744

RESUMO

BACKGROUND Berberine (BBR), a natural alkaloid isolated from Coptis chinensis, has frequently been reported as an antidiabetic reagent, partly due to its lipid-lowering activity. Evidence suggests that BBR ameliorates palmitate-induced lipid deposition and apoptosis in renal tubular epithelial cells (TECs), which tracks in tandem with the enhancement of peroxisome proliferator-activated receptor alpha (PPAR-alpha). The study aim was to investigate the roles of BBR in renal lipotoxicity in vitro, and investigate whether PPAR-alpha was the underlying mechanism. MATERIAL AND METHODS Human TECs (HK-2 cells) were injured with palmitic acid (PA), and then treated with BBR, BBR+PPAR-alpha inhibitor (GW6471), and PA+PPAR-alpha agonist (fenofibrate). Endoplasmic reticulum (ER) stress was assessed by measuring the expression of prospective evaluation of radial keratotomy (PERK), C/EBP-homologous protein (CHOP), and 78 kDa glucose-regulated protein (GRP78). Lipid metabolism was assessed by determining lipid anabolism-associated genes, including fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and lipoprotein lipase (LPL), as well as lipid catabolism-associated gene, including carnitine palmitoyl transferase 1 (CPT1). Inflammatory response of HK-2 cells was evaluated by measuring interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha. Cell apoptosis and protein levels of cleaved-caspase-3 were evaluated. RESULTS PA downregulated PPAR-alpha and induced server lipotoxicity in HK-2 cells by ER stress, increasing lipid deposition, and elevating inflammatory response of HK-2 cells accompanied with inducting cell apoptosis and cleaved-caspase-3, which were obviously reversed by additional treatment of BBR or PPAR-alpha agonist. However, the protective effect of BBR in PA-induced lipotoxicity in HK-2 cells was significantly ameliorated by PPAR-alpha inhibitor. CONCLUSIONS BBR attenuated PA-induced lipotoxicity via the PPAR-alpha pathway.


Assuntos
Berberina/farmacologia , PPAR alfa/metabolismo , Ácido Palmítico/toxicidade , Apoptose/efeitos dos fármacos , Linhagem Celular , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Inflamação/patologia , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
6.
Nutrients ; 11(9)2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514316

RESUMO

Diets high in saturated fatty acids (FA) represent a risk factor for the development of obesity and associated metabolic disorders, partly through their impact on the epithelial cell barrier integrity. We hypothesized that unsaturated FA could alleviate saturated FA-induced endoplasmic reticulum (ER) stress occurring in intestinal secretory goblet cells, and consequently the reduced synthesis and secretion of mucins that form the protective mucus barrier. To investigate this hypothesis, we treated well-differentiated human colonic LS174T goblet cells with palmitic acid (PAL)-the most commonly used inducer of lipotoxicity in in vitro systems-or n-9, n-6, or n-3 unsaturated fatty acids alone or in co-treatment with PAL, and measured the impact of such treatments on ER stress and Muc2 production. Our results showed that only eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids protect goblet cells against ER stress-mediated altered Muc2 secretion induced by PAL, whereas neither linolenic acid nor n-9 and n-6 FA are able to provide such protection. We conclude that EPA and DHA could represent potential therapeutic nutrients against the detrimental lipotoxicity of saturated fatty acids, associated with type 2 diabetes and obesity or inflammatory bowel disease. These in vitro data remain to be explored in vivo in a context of dietary obesity.


Assuntos
Ácidos Docosa-Hexaenoicos/farmacologia , Ácido Eicosapentaenoico/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Células Caliciformes/efeitos dos fármacos , Mucina-2/metabolismo , Ácido Palmítico/toxicidade , Linhagem Celular , Citoproteção , Células Caliciformes/metabolismo , Células Caliciformes/patologia , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Via Secretória
7.
Am J Respir Cell Mol Biol ; 61(6): 737-746, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31461627

RESUMO

The impact of lipotoxicity on the development of lung fibrosis is unclear. Saturated fatty acids, such as palmitic acid (PA), activate endoplasmic reticulum (ER) stress, a cellular stress response associated with the development of idiopathic pulmonary fibrosis (IPF). We tested the hypothesis that PA increases susceptibility to lung epithelial cell death and experimental fibrosis by modulating ER stress. Total liquid chromatography and mass spectrometry were used to measure fatty acid content in IPF lungs. Wild-type mice were fed a high-fat diet (HFD) rich in PA or a standard diet and subjected to bleomycin-induced lung injury. Lung fibrosis was determined by hydroxyproline content. Mouse lung epithelial cells were treated with PA. ER stress and cell death were assessed by Western blotting, TUNEL staining, and cell viability assays. IPF lungs had a higher level of PA compared with controls. Bleomycin-exposed mice fed an HFD had significantly increased pulmonary fibrosis associated with increased cell death and ER stress compared with those fed a standard diet. PA increased apoptosis and activation of the unfolded protein response in lung epithelial cells. This was attenuated by genetic deletion and chemical inhibition of CD36, a fatty acid transporter. In conclusion, consumption of an HFD rich in saturated fat increases susceptibility to lung fibrosis and ER stress, and PA mediates lung epithelial cell death and ER stress via CD36. These findings demonstrate that lipotoxicity may have a significant impact on the development of lung injury and fibrosis by enhancing pro-death ER stress pathways.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Ácido Palmítico/toxicidade , Fibrose Pulmonar/induzido quimicamente , Animais , Apoptose/efeitos dos fármacos , Antígenos CD36/deficiência , Antígenos CD36/fisiologia , Células Epiteliais/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ácido Palmítico/administração & dosagem , Ácido Palmítico/farmacocinética , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia
8.
Biol Res ; 52(1): 44, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31426858

RESUMO

BACKGROUND: Free fatty acid receptor 1 (FFAR1) is G-protein coupled receptor predominantly expressed in pancreatic ß-cells that is activated by a variety of free fatty acids (FFAs). Once activated, it promotes glucose-stimulated insulin secretion (GSIS). However, increased levels of FFAs lead to lipotoxicity, inducing loss of ß-cell function. FFAR1 plays a key role in the development of type 2 diabetes (T2D), and previous studies have indicated the importance of developing anti-diabetic therapies against FFAR1, although its role in the regulation of ß-cell function remains unclear. The present study investigated the role of FFAR1 under lipotoxic conditions using palmitic acid (PA). The rat insulinoma 1 clone 832/13 (INS-1 832/13) cell line was used as a model as it physiologically resembles native pancreatic ß-cells. Key players of the insulin signaling pathway, such as mTOR, Akt, IRS-1, and the insulin receptor (INSR1ß), were selected as candidates to be analyzed under lipotoxic conditions. RESULTS: We revealed that PA-induced lipotoxicity affected GSIS in INS-1 cells and negatively modulated the activity of both IRS-1 and Akt. Reduced phosphorylation of both IRS-1 S636/639 and Akt S473 was observed, in addition to decreased expression of both INSR1ß and FFAR1. Moreover, transient knockdown of FFAR1 led to a reduction in IRS-1 mRNA expression and an increase in INSR1ß mRNA. Finally, PA affected localization of FFAR1 from the cytoplasm to the perinucleus. CONCLUSIONS: In conclusion, our study suggests a novel regulatory involvement of FFAR1 in crosstalk with mTOR-Akt and IRS-1 signaling in ß-cells under lipotoxic conditions.


Assuntos
Células Secretoras de Insulina/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Ácido Palmítico/toxicidade , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Apoptose , Linhagem Celular , Células Secretoras de Insulina/metabolismo , Ratos , Transdução de Sinais
9.
Nutrients ; 11(9)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443411

RESUMO

Hyperglycemia and hyperlipidemia are the hallmarks of diabetes and obesity. Experimental and epidemiological studies have suggested that dietary management and caloric restriction are beneficial in reducing the complications of diabesity. Studies have suggested that increased availability of energy metabolites like glucose and saturated fatty acids induces metabolic, oxidative, and mitochondrial stress, accompanied by inflammation that may lead to chronic complications in diabetes. In the present study, we used human hepatoma HepG2 cells to investigate the effects of high glucose (25 mM) and high palmitic acid (up to 0.3 mM) on metabolic-, inflammatory-, and redox-stress-associated alterations in these cells. Our results showed increased lipid, protein, and DNA damage, leading to caspase-dependent apoptosis and mitochondrial dysfunction. Glucolipotoxicity increased ROS production and redox stress appeared to alter mitochondrial membrane potential and bioenergetics. Our results also demonstrate the enhanced ability of cytochrome P450s-dependent drug metabolism and antioxidant adaptation in HepG2 cells treated with palmitic acid, which was further augmented with high glucose. Altered NF-kB/AMPK/mTOR-dependent cell signaling and inflammatory (IL6/TNF-α) responses were also observed. Our results suggest that the presence of high-energy metabolites enhances apoptosis while suppressing autophagy by inducing inflammatory and oxidative stress responses that may be responsible for alterations in cell signaling and metabolism.


Assuntos
Apoptose/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Glucose/toxicidade , Hepatócitos/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ácido Palmítico/toxicidade , Proteínas Quinases Ativadas por AMP/metabolismo , Autofagia/efeitos dos fármacos , Células Hep G2 , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Mediadores da Inflamação/metabolismo , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Hepáticas/patologia , NF-kappa B/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo
10.
Cells ; 8(8)2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31412623

RESUMO

Metabolic overload by saturated fatty acids (SFA), which comprises ß-cell function, and impaired glucose-stimulated insulin secretion are frequently observed in patients suffering from obesity and type 2 diabetes mellitus. The increase of intracellular Ca2+ triggers insulin granule release, therefore several mechanisms regulate Ca2+ efflux within the ß-cells, among others, the plasma membrane Ca2+-ATPase (PMCA). In this work, we describe that lipotoxicity mediated mainly by the saturated palmitic acid (PA) (16C) is associated with loss of protein homeostasis (proteostasis) and potentially cell viability, a phenomenon that was induced to a lesser extent by stearic (18C), myristic (14C) and lauric (12C) acids. PA was localized on endoplasmic reticulum, activating arms of the unfolded protein response (UPR), as also promoted by lipopolysaccharides (LPS)-endotoxins. In particular, our findings demonstrate an alteration in PMCA1/4 expression caused by PA and LPS which trigger the UPR, affecting not only insulin release and contributing to ß-cell mass reduction, but also increasing reactive nitrogen species. Nonetheless, stearic acid (SA) did not show these effects. Remarkably, the proteolytic degradation of PMCA1/4 prompted by PA and LPS was avoided by the action of monounsaturated fatty acids such as oleic and palmitoleic acid. Oleic acid recovered cell viability after treatment with PA/LPS and, more interestingly, relieved endoplasmic reticulum (ER) stress. While palmitoleic acid improved the insulin release, this fatty acid seems to have more relevant effects upon the expression of regulatory pumps of intracellular Ca2+. Therefore, chain length and unsaturation of fatty acids are determinant cues in proteostasis of ß-cells and, consequently, on the regulation of calcium and insulin secretion.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Ácidos Graxos Monoinsaturados/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Ácido Oleico/farmacologia , Ácido Palmítico/toxicidade , Proteostase/efeitos dos fármacos , Animais , Cálcio/metabolismo , Linhagem Celular , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Lipopolissacarídeos/toxicidade , ATPases Transportadoras de Cálcio da Membrana Plasmática/metabolismo , Ratos , Resposta a Proteínas não Dobradas/efeitos dos fármacos
11.
Mol Cell Biochem ; 461(1-2): 65-72, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31327095

RESUMO

Azoramide is identified as a new compound with the dual properties for the improvement of ER-folding capacity in various cells as well as for the treatment of T2DM. Although the effect of azoramide in glucose-homeostasis in mammalians is not known very well, a limited number of experimental studies showed that it could improve the insulin sensitivity in genetically obese mice. Therefore, here, we aimed to investigate the direct effect of azoramide on insulin signaling in insulin-resistant (IR) cardiomyocytes using IR-modelled ventricular cardiomyocytes. This model was established in H9c2 cells using palmitic acid incubation (50-µM for 24-h). The development of IR in cells was verified by monitoring the cellular 2-DG6P uptake assays in these treated cells. The 2-DG6P uptake was 50% less in the IR-cells compared to the control cells, while azoramide treatment (20-µM for 48-h) could prevent fully that decrease. In addition, azoramide treatment markedly preserved the IR-induced less ATP production and high-ROS production in these IR-cells. Furthermore, this treatment prevented the functional changes in mitochondria characterized by depolarized mitochondrial membrane potential and mitochondrial fusion or fusion-related protein levels as well as cellular ATP level. Moreover, this treatment provided marked protection against IR-associated changes in the insulin signaling pathway in cells, including recovery in the phosphorylation of IRS1 and Akt as well as the protein level of GLUT4 and Akt. Our present results, for the first time, demonstrated that azoramide plays an important protective role in IR-cardiomyocytes, at most, protective action on mitochondria. Therefore, one can suggest that azoramide, as a novel regulator, can provide direct cardioprotection in the IR-heart, at most, via affecting mitochondria and can be a good candidate as a new drug for the treatment of IR-associated cardiovascular disorders in mammalians with systemic IR.


Assuntos
Amidas/farmacologia , Resistência à Insulina , Mitocôndrias/metabolismo , Ácido Palmítico/toxicidade , Tiazóis/farmacologia , Trifosfato de Adenosina/metabolismo , Animais , Linhagem Celular , Glucose/metabolismo , Insulina/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Dinâmica Mitocondrial/efeitos dos fármacos , Ratos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
12.
Molecules ; 24(13)2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31266188

RESUMO

Ketosis is a nutritional metabolic disease in dairy cows, and researches indicated that ketonic cows always accompany reproductive problems. When ketosis occurs, the levels of non-esterified fatty acids (NEFAs) and ß-hydroxybutyrate (BHBA) in the blood increase significantly. Palmitic acid (PA) is a main component of saturated fatty acids composing NEFA. The aim of this study was to investigate whether high levels of PA and BHBA induce inflammatory responses and regulatory mechanisms in bovine endometrial cells (BEND). Using an enzyme-linked immunosorbent assay, quantitative real-time PCR, and western blotting, we evaluated oxidative stress, pro-inflammatory factors, and the nuclear factor (NF)-κB pathway in cultured BEND cells treated with different concentrations of PA, BHBA, pyrrolidinedithiocarbamate (PDTC, an NF-κB pathway inhibitor), and N-acetylcysteine (NAC, an antioxidant). The content of malondialdehyde was significantly higher, the content of glutathione was lower, and antioxidant activity-glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity-was lower in treated cells compared with control cells. PA- and BHBA-induced oxidative stress activated the NF-κB signaling pathway and upregulated the release of pro-inflammatory factors. Moreover, PA- and BHBA-induced activation of NF-κB-mediated inflammatory responses was inhibited by PDTC and NAC. High concentrations of PA and BHBA induce inflammatory responses in BEND cells by activating oxidative stress-mediated NF-κB signaling.


Assuntos
Ácido 3-Hidroxibutírico/toxicidade , Endométrio/patologia , NF-kappa B/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ácido Palmítico/toxicidade , Transdução de Sinais/efeitos dos fármacos , Animais , Bovinos , Linhagem Celular , Endométrio/fisiologia , Feminino , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/patologia
13.
Mol Cell Biochem ; 460(1-2): 81-92, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31183735

RESUMO

High levels of circulating free fatty acids often trigger pancreatic ß cell dysfunction during the development of type 2 diabetes. Silibinin, the main component of Silybum marianum fruit extract (silymarin), is reported to have anti-diabetic effect. This study is designed to determine the protective effect of silibinin on palmitic acid-induced damage in a rat pancreatic ß-cell line, INS-1 cells. Our results demonstrate that silibinin improves cell viability, enhances insulin synthesis and secretion, and resumes normal mitochondrial function in palmitic acid-treated INS-1 cells. An accumulating body of evidence has shown that the estrogen receptors are key molecules involved in glucose and lipid metabolism. Our results suggest that silibinin upregulates ERα signaling pathway from the finding that ERα-specific inhibitors abolish the anti-lipotoxic effect of silibinin. In conclusion, these findings suggest that silibinin protects INS-1 cells against apoptosis and mitochondrial damage through upregulation of ERα pathway.


Assuntos
Apoptose/efeitos dos fármacos , Receptor alfa de Estrogênio/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Mitocôndrias/patologia , Ácido Palmítico/toxicidade , Silibina/farmacologia , Animais , Linhagem Celular Tumoral , Citoproteção/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Substâncias Protetoras/farmacologia , Ratos , Silibina/química , Regulação para Cima/efeitos dos fármacos
14.
Int J Biol Macromol ; 133: 1063-1071, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31034903

RESUMO

Palmitic acid (PA) is known to induce lipotoxicity, a metabolic syndrome as a result of lipid accumulation in multiple cell lines. Bioactive phytochemicals derived from vegetables and fruits have gained increasing attention owing to their potential on suppressing the detrimental effect of excessive PA accumulation. However, the protective effect of natural phytochemicals derived from Rubus chingii Hu, a kind of fruit widely grown in China, against PA-induced lipotoxicity is still uncleared. In the present study, we therefore extracted the polysaccharide from Rubus chingii Hu, and identified its chemical structure. Structural characterization by HPLC, HPGPC, IR spectroscopy and GC indicated that the polysaccharide mainly consists of galacturonic acid and arabinose with copious 1 → 2 glycosidic linkages in its backbone. In addition, our results showed the cytoprotective effect of the polysaccharide against PA-induced lipotoxicity in normal human hepatocyte cell line L02. Further study indicated that the polysaccharide mitigated oxidative stress through impeding cellular reactive oxygen species (ROS) accumulation, alleviating mitochondrial membrane potential (MMP) collapse and attenuating glutathione (GSH) reduction. Overall, this study revealed that Rubus chingii Hu polysaccharide was capable of effectively alleviating palmitic acid-induced lipotoxicity, which provided a novel perspective of the health-promoting potential of isolated polysaccharide.


Assuntos
Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Ácido Palmítico/toxicidade , Polissacarídeos/farmacologia , Rubus/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Hepatócitos/citologia , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Oxirredução/efeitos dos fármacos , Ácido Periódico/metabolismo , Polissacarídeos/química , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/metabolismo
15.
Int J Mol Med ; 43(5): 2187-2198, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30896786

RESUMO

Metformin serves an important role in improving the functions of endothelial progenitor cells (EPCs). MicroRNAs (miRNAs), small non­coding RNAs, have been investigated as significant regulators of EPC vascular functions. The present study investigated the molecular crosstalk between metformin and miRNA­130a (miR­130a) in the functions of EPCs exposed to palmitic acid (PA). Isolated EPCs were treated with metformin, PA, and metformin + PA, respectively. Cell Counting Kit­8, Transwell and Matrigel assays were performed to detect the proliferation, migration and tube formation ability of EPCs following different treatments. The expression of miR­130a, phosphatase and tensin homolog (PTEN) and phosphorylated­AKT was analyzed by reverse transcription­quantitative polymerase chain reaction and western blotting. The specific mechanism underlying the function of metformin in EPCs was further elucidated by transfecting miR­130a mimics and inhibitor to overexpress and inhibit the expression of miR­130a in EPCs, respectively. EPCs exhibited impaired functions of proliferation (P<0.01 compared with the control), migration (P<0.01 compared with the control) and tube formation (P<0.01 compared with the control) following treatment with PA, and the expression levels of miR­130a and PTEN were decreased and increased, respectively. However, the presence of metformin, or the overexpression of miR­130a using miR­130a mimic alleviated the impairment of angiogenesis and proliferation, decreased the expression of PTEN and activated the phosphoinositide­3 kinase/AKT pathway in EPCs exposed to PA. By contrast, downregulating the expression of miR­130a with a miR­130a inhibitor reversed the metformin­mediated protection. These results demonstrate the beneficial effect of miR­130a/PTEN on EPC functions, which can be regulated by metformin. The effects of metformin on improving PA­induced EPC dysfunction are mediated by miR­130a and PTEN, which may assist in the prevention and/or treatment of diabetic vascular disease.


Assuntos
Células Progenitoras Endoteliais/patologia , Metformina/farmacologia , MicroRNAs/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Ácido Palmítico/toxicidade , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Citoproteção/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Células Progenitoras Endoteliais/efeitos dos fármacos , Células Progenitoras Endoteliais/metabolismo , Masculino , MicroRNAs/genética , Neovascularização Fisiológica/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Substâncias Protetoras/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley
16.
Mol Cell Endocrinol ; 486: 65-78, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30822454

RESUMO

Palmitic acid (PA) induces several metabolic and molecular changes in astrocytes, and, it is involved in pathological conditions related to neurodegenerative diseases. Previously, we demonstrated that tibolone, a synthetic steroid with estrogenic, progestogenic and androgenic actions, protects cells from mitochondrial damage and morphological changes induced by PA. Here, we have evaluated which estrogen receptor is involved in protective actions of tibolone and analyzed whether tibolone reverses gene expression changes induced by PA. Tibolone actions on astrocytic cells were mimicked by agonists of estrogen receptor α (ERα) and ß (ERß), but the blockade of both ERs suggested a predominance of ERß on mitochondria membrane potential. Expression analysis showed a significant effect of tibolone on genes associated with inflammation such as IL6, IL1B and miR155-3p. It is noteworthy that tibolone attenuated the increased expression of TERT, TERC and DNMT3B genes induced by palmitic acid. Our results suggest that tibolone has anti-inflammatory effects and can modulate pathways associated with DNA methylation and telomeric complex. However, future studies are needed to elucidate the role of epigenetic mechanisms and telomere-associated proteins on tibolone actions.


Assuntos
Astrócitos/metabolismo , Receptor alfa de Estrogênio/metabolismo , Inflamação/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Norpregnenos/farmacologia , Ácido Palmítico/toxicidade , Astrócitos/efeitos dos fármacos , Linhagem Celular , Epigênese Genética/efeitos dos fármacos , Estradiol/farmacologia , Receptor alfa de Estrogênio/agonistas , Receptor alfa de Estrogênio/antagonistas & inibidores , Receptor beta de Estrogênio/agonistas , Receptor beta de Estrogênio/antagonistas & inibidores , Receptor beta de Estrogênio/metabolismo , Humanos , Inflamação/genética , Nitrilos/farmacologia , Fenóis , Substâncias Protetoras/farmacologia , Pirazóis , Telomerase/genética , Telomerase/metabolismo , Telômero/metabolismo , Fatores de Transcrição/metabolismo
17.
Mol Cell ; 74(1): 45-58.e7, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30846317

RESUMO

Cells require a constant supply of fatty acids to survive and proliferate. Fatty acids incorporate into membrane and storage glycerolipids through a series of endoplasmic reticulum (ER) enzymes, but how these enzymes are regulated is not well understood. Here, using a combination of CRISPR-based genetic screens and unbiased lipidomics, we identified calcineurin B homologous protein 1 (CHP1) as a major regulator of ER glycerolipid synthesis. Loss of CHP1 severely reduces fatty acid incorporation and storage in mammalian cells and invertebrates. Mechanistically, CHP1 binds and activates GPAT4, which catalyzes the initial rate-limiting step in glycerolipid synthesis. GPAT4 activity requires CHP1 to be N-myristoylated, forming a key molecular interface between the two proteins. Interestingly, upon CHP1 loss, the peroxisomal enzyme, GNPAT, partially compensates for the loss of ER lipid synthesis, enabling cell proliferation. Thus, our work identifies a conserved regulator of glycerolipid metabolism and reveals plasticity in lipid synthesis of proliferating cells.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Retículo Endoplasmático/enzimologia , Glicerídeos/biossíntese , Glicerol-3-Fosfato O-Aciltransferase/metabolismo , Lipogênese , Células 3T3 , Aciltransferases/genética , Aciltransferases/metabolismo , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Ligação ao Cálcio/genética , Proliferação de Células , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/patologia , Ativação Enzimática , Regulação Enzimológica da Expressão Gênica , Glicerol-3-Fosfato O-Aciltransferase/genética , Células HEK293 , Células HeLa , Células Hep G2 , Humanos , Células Jurkat , Lipogênese/efeitos dos fármacos , Lipogênese/genética , Camundongos , Ácido Palmítico/toxicidade , Ligação Proteica
18.
Mol Cell ; 74(1): 32-44.e8, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30846318

RESUMO

Excessive levels of saturated fatty acids are toxic to cells, although the basis for this lipotoxicity remains incompletely understood. Here, we analyzed the transcriptome, lipidome, and genetic interactions of human leukemia cells exposed to palmitate. Palmitate treatment increased saturated glycerolipids, accompanied by a transcriptional stress response, including upregulation of the endoplasmic reticulum (ER) stress response. A comprehensive genome-wide short hairpin RNA (shRNA) screen identified >350 genes modulating lipotoxicity. Among previously unknown genetic modifiers of lipotoxicity, depletion of RNF213, a putative ubiquitin ligase mutated in Moyamoya vascular disease, protected cells from lipotoxicity. On a broader level, integration of our comprehensive datasets revealed that changes in di-saturated glycerolipids, but not other lipid classes, are central to lipotoxicity in this model. Consistent with this, inhibition of ER-localized glycerol-3-phosphate acyltransferase activity protected from all aspects of lipotoxicity. Identification of genes modulating the response to saturated fatty acids may reveal novel therapeutic strategies for treating metabolic diseases linked to lipotoxicity.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/efeitos dos fármacos , Glicerídeos/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Ácido Palmítico/toxicidade , Aciltransferases/genética , Aciltransferases/metabolismo , Adenosina Trifosfatases/metabolismo , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/patologia , Estresse do Retículo Endoplasmático/genética , Regulação Enzimológica da Expressão Gênica , Células HeLa , Células Hep G2 , Humanos , Células K562 , Metabolismo dos Lipídeos/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Transcriptoma , Ubiquitina-Proteína Ligases/metabolismo
19.
Hum Exp Toxicol ; 38(6): 655-664, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30859861

RESUMO

Diabetic cardiomyopathy is mediated by multiple molecular mechanisms including endoplasmic reticulum (ER) stress. Curcumin, a phenolic compound, has cytoprotective properties, but its potential protective action against diabetic cardiomyopathy and the related molecular mechanisms are not fully elucidated. In this study, we evaluated the effects of curcumin on cell viability and apoptosis in palmitic acid (PA)-treated H9C2 cardiomyocytes and investigated the signaling pathways involved. Treatment with PA reduced cell viability, induced apoptosis, enhanced apoptosis-related protein expression (Caspase 3 and BCL-2 associated X protein (BAX)), and activated ER stress marker protein expression (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)). Curcumin attenuated PA-induced reduction in cell viability and activation of apoptosis, Caspase 3 activity, BAX, CHOP, and GRP78 expression. 4-Phenylbutyric acid (4-PBA) attenuated the PA-induced effects on cell viability and apoptosis, similar to curcumin. Both curcumin and 4-PBA also attenuated PA-induced increase in ER stress protein (CHOP and GRP78) expression. Curcumin also protected against cytotoxicity, apoptosis, and ER stress induced by thapsigargin. These findings indicate that PA triggers apoptosis in H9C2 cells via ER stress pathways and curcumin protects against this phenomenon.


Assuntos
Apoptose/efeitos dos fármacos , Curcumina/farmacologia , Miócitos Cardíacos/efeitos dos fármacos , Ácido Palmítico/toxicidade , Substâncias Protetoras/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Proteínas de Choque Térmico/metabolismo , Humanos , Miócitos Cardíacos/metabolismo , Fator de Transcrição CHOP/metabolismo , Proteína X Associada a bcl-2/metabolismo
20.
Biochem Biophys Res Commun ; 508(4): 1252-1258, 2019 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-30558790

RESUMO

Recent studies have reported elevated expression of miR-181a in patients with non-alcoholic fatty liver disease (NAFLD), suggesting that it may play an important role in liver lipid metabolism and insulin resistance. We aimed to investigate the effect of miR-181a in lipid metabolism and find new treatments for NAFLD. The expression level of miR-181a in NAFLD patient serum and a palmitic acid (PA)-induced NAFLD cell model was examined by Q-PCR. Oil red O staining and triglyceride assays were used to assess lipid accumulation in hepatocytes. Western blotting was used to detect the protein expression levels of peroxisome proliferator-activated receptor-α (PPARα) and the fatty acid ß-oxidation-related genes. Direct interactions were validated by dual-luciferase reporter gene assays. MiR-181a expression was significantly upregulated in the serum of NAFLD patients and PA-induced hepatocytes. Inhibition of miR-181a expression resulted in the increased expression of PPARα and its downstream genes, and PA-induced lipid accumulation in hepatocytes was also inhibited. Upregulation of miR-181a resulted in the downregulation of its direct target PPARα and downstream gene expression of PPARα as well as aggravated lipid accumulation in hepatocytes. At the same time, the increased expression of PPARα can offset lipid accumulation in hepatocytes induced by miR-181a mimics. This study demonstrates that reducing the expression of miR-181a may improve lipid metabolism in NAFLD. The downregulation of miR-181a expression can be a therapeutic strategy for NAFLD by modulating its target PPARα.


Assuntos
Metabolismo dos Lipídeos/genética , MicroRNAs/genética , Hepatopatia Gordurosa não Alcoólica/genética , PPAR alfa/genética , Regulação para Cima/genética , Regiões 3' não Traduzidas/genética , Animais , Sequência de Bases , Linhagem Celular , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Camundongos Endogâmicos C57BL , MicroRNAs/sangue , MicroRNAs/metabolismo , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/patologia , Oxirredução , PPAR alfa/metabolismo , Ácido Palmítico/toxicidade , Regulação para Cima/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA