Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.266
Filtrar
1.
Nat Commun ; 12(1): 213, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431899

RESUMO

High-fat diet (HFD) decreases insulin sensitivity. How high-fat diet causes insulin resistance is largely unknown. Here, we show that lean mice become insulin resistant after being administered exosomes isolated from the feces of obese mice fed a HFD or from patients with type II diabetes. HFD altered the lipid composition of exosomes from predominantly phosphatidylethanolamine (PE) in exosomes from lean animals (L-Exo) to phosphatidylcholine (PC) in exosomes from obese animals (H-Exo). Mechanistically, we show that intestinal H-Exo is taken up by macrophages and hepatocytes, leading to inhibition of the insulin signaling pathway. Moreover, exosome-derived PC binds to and activates AhR, leading to inhibition of the expression of genes essential for activation of the insulin signaling pathway, including IRS-2, and its downstream genes PI3K and Akt. Together, our results reveal HFD-induced exosomes as potential contributors to the development of insulin resistance. Intestinal exosomes thus have potential as broad therapeutic targets.


Assuntos
Dieta Hiperlipídica , Exossomos/metabolismo , Resistência à Insulina/genética , Fosfatidilcolinas/metabolismo , Regulação para Cima/genética , Tecido Adiposo/metabolismo , Animais , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Dislipidemias/complicações , Dislipidemias/genética , Dislipidemias/patologia , Células Epiteliais/metabolismo , Fígado Gorduroso/complicações , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Fezes , Regulação da Expressão Gênica , Intolerância à Glucose , Proteínas de Fluorescência Verde/metabolismo , Humanos , Insulina/metabolismo , Interleucina-6/sangue , Intestinos/citologia , Lipídeos/química , Fígado/metabolismo , Fígado/patologia , Ativação de Macrófagos , Camundongos Endogâmicos C57BL , Receptores de Hidrocarboneto Arílico/metabolismo , Transdução de Sinais , Tetraspanina 30/metabolismo , Fator de Necrose Tumoral alfa/sangue
2.
Plant Physiol Biochem ; 159: 148-159, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360238

RESUMO

We used electrospray ionization tandem mass spectrometry to profile glycerolipids in the TOC159 null mutant of Arabidopsis, which is referred to as plastid protein import 2, or ppi2. The goal was to evaluate the impact of a defective atToc159 receptor in the accumulation of plastid lipids. The ppi2 mutant is severely impaired in the accumulation of monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and phosphatidylglycerol (PG), which are major components of the thylakoid membranes. Major molecular species of MGDG and DGDG are drastically decreased, which is consistent with our previous findings of decreased levels of hexadecatrienoic and linolenic acids. Under normal growth conditions, the ppi2 mutant accumulated significantly lower levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). In the cold-acclimated mutant, the amounts of PE and PI were similar to the wildtype level, which indicates that the ER pathway of lipid synthesis was functional in the mutant. The cold-acclimated ppi2 mutant accumulated increased amounts of phosphatidic acid (PA), which was mirrored by an increase in phospholipase Dα (PLDα) transcript levels. These data suggest that PLDα activity contributed to the accumulation of cold-induced PA in the ppi2 mutant. The accumulation of major molecular species in PA indicates that cold-induced PA originated from the degradation of both plastidial and extraplastidial lipids. Compared with the wildtype, the ppi2 mutant had a low double bond index and high acyl chain length, which is indicative of decreased membrane fluidity. Taken together, these data indicate that a defective atToc159 receptor severely impaired the plastid pathway of lipid synthesis, which negatively affected the synthesis and/or accumulation of PC.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , GTP Fosfo-Hidrolases , Metabolismo dos Lipídeos , Proteínas de Membrana , Fosfatidilcolinas , Plastídeos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Metabolismo dos Lipídeos/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mutação , Fosfatidilcolinas/genética , Fosfatidilcolinas/metabolismo , Plastídeos/genética , Plastídeos/metabolismo
3.
Yakugaku Zasshi ; 140(11): 1329-1334, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-33132268

RESUMO

Biliary lipids primarily consist of bile salts, phospholipids, and cholesterol. Bile salts have potent detergent properties and deleterious effects on the cell membrane and are cytotoxic to hepatocytes. We have previously reported that phosphatidylcholine (PC), the predominant bile phospholipid, protects hepatocytes from the cytotoxicity of bile salts, whereas cholesterol reverses the cytoprotective effects of PC against bile salts. ABCB4, a member of the ATP-binding cassette transporter family, secretes biliary phospholipids, especially PC, from the hepatocytes into the bile. Using Abcb4 knockout mice and HEK293 cells that stably expressed ABCB4, we examined the effects of taurine- or glycine-conjugated cholate, ursodeoxycholate, and hyodeoxycholate on the ABCB4-mediated efflux of PC. We observed that the biliary secretion of PC in wild-type mice significantly increased following infusion of all the tested bile salts, especially taurohyodeoxycholate. On the other hand, the biliary secretion of PC in Abcb4 knockout mice was not affected by the bile salt infusions. The results also demonstrated that the efflux of PC from ABCB4-expressing HEK293 cells was significantly stimulated by taurohyodeoxycholate, which has a strong potential to form mixed micelles with PC. Furthermore, the results of our study emphasized the possibility that the specific interactions of bile salts with ABCB4 are necessary for the release of PC molecules from the binding pocket of ABCB4 into the aqueous environment. Further understanding of this mechanism will aid in the development of novel therapeutic agents for cholestatic liver diseases.


Assuntos
Subfamília B de Transportador de Cassetes de Ligação de ATP/fisiologia , Ácidos e Sais Biliares/efeitos adversos , Bile/metabolismo , Doença Hepática Crônica Induzida por Substâncias e Drogas/etiologia , Doença Hepática Crônica Induzida por Substâncias e Drogas/genética , Desenvolvimento de Medicamentos , Fosfatidilcolinas/farmacologia , Fosfolipídeos/metabolismo , Ácido Taurodesoxicólico/análogos & derivados , Animais , Doença Hepática Crônica Induzida por Substâncias e Drogas/tratamento farmacológico , Colesterol/farmacologia , Células HEK293 , Hepatócitos/metabolismo , Humanos , Camundongos Knockout , Fosfatidilcolinas/metabolismo , Ácido Taurodesoxicólico/farmacologia
4.
Nat Commun ; 11(1): 4480, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32900992

RESUMO

Macroautophagy initiates by formation of isolation membranes, but the source of phospholipids for the membrane biogenesis remains elusive. Here, we show that autophagic membranes incorporate newly synthesized phosphatidylcholine, and that CTP:phosphocholine cytidylyltransferase ß3 (CCTß3), an isoform of the rate-limiting enzyme in the Kennedy pathway, plays an essential role. In starved mouse embryo fibroblasts, CCTß3 is initially recruited to autophagic membranes, but upon prolonged starvation, it concentrates on lipid droplets that are generated from autophagic degradation products. Omegasomes and isolation membranes emanate from around those lipid droplets. Autophagy in prolonged starvation is suppressed by knockdown of CCTß3 and is enhanced by its overexpression. This CCTß3-dependent mechanism is also present in U2OS, an osteosarcoma cell line, and autophagy and cell survival in starvation are decreased by CCTß3 depletion. The results demonstrate that phosphatidylcholine synthesis through CCTß3 activation on lipid droplets is crucial for sustaining autophagy and long-term cell survival.


Assuntos
Autofagia/fisiologia , Colina-Fosfato Citidililtransferase/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Animais , Autofagossomos/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular , Colina-Fosfato Citidililtransferase/antagonistas & inibidores , Colina-Fosfato Citidililtransferase/genética , Meios de Cultura , Ativação Enzimática , Técnicas de Silenciamento de Genes , Humanos , Gotículas Lipídicas/metabolismo , Camundongos , Modelos Biológicos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Osteossarcoma/metabolismo , Osteossarcoma/patologia , Fosfatidilcolinas/metabolismo
5.
Food Chem ; 332: 127384, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615384

RESUMO

Dairy polar lipids (PL) seem to exhibit antiplatelet effects. However, it is not known what molecular species may be responsible. In this study, we confirmed using C30 reversed-phase (C30RP) ultra-high-performance liquid chromatography (UHPLC) coupled to high resolution accurate mass tandem mass spectrometry (HRAM-MS/MS) that fermentation of yoghurts from ovine milk using specific starter cultures altered the PL composition. These lipid alterations occurred concomitant with increased antithrombotic properties of the yoghurts PL fractions against platelet-activating factor (PAF) and thrombin-induced platelet aggregation. Specifically, elevation in phosphatidylethanolamine (PE), sphingomyelin (SM), phosphatidylcholine (PC) and their molecular species were observed following yoghurt fermentation. Furthermore, PC(18:0/18:1), PE(18:1/18:2), SM(d18:0/22:0) and several other molecular species were significantly inversely correlated with the inhibition of PAF and thrombin. These molecular species were abundant in the most bioactive yoghurts fermented by S. thermophilus and L. acidophilus, which suggest that fermentation by these microorganisms increases the antithrombotic properties of ovine milk PL.


Assuntos
Lipídeos/análise , Leite/metabolismo , Inibidores da Agregação de Plaquetas/análise , Iogurte/análise , Animais , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Cromatografia Líquida de Alta Pressão , Fermentação , Lipídeos/farmacologia , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação de Plaquetas/farmacologia , Ovinos , Esfingomielinas/metabolismo , Espectrometria de Massas em Tandem , Trombina/farmacologia
6.
Leg Med (Tokyo) ; 46: 101724, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32516737

RESUMO

Hypochlorous acid, produced by myeloperoxidase upon neutrophil activation, can oxidize various compounds and exert antimicrobial activity in vivo. To elucidate the mechanisms underlying the reactions of the unsaturated phosphatidylcholines, which abound in cell membranes, with hypochlorous acid, we identified and examined phosphatidylcholine chlorination and oxidation products formed under various reaction conditions. We first investigated the products of unsaturated phosphatidylcholine and hypochlorous acid reaction with respect to hypochlorite concentration and reaction time. Next, we examined the lipids extracted postmortem from human abscesses. For all the analyses, we used liquid chromatography-quadrupole time-of-flight mass spectrometry. Various compounds, including phosphatidylcholine chlorohydrin and phosphatidylcholine hydroxide/epoxide, were detected. Oxidized phosphatidylcholines were mainly detectable upon reaction with low concentrations of sodium hypochlorite, whereas chlorinated phosphatidylcholines formed in the presence of higher concentrations. In human abscesses, oxidized phosphatidylcholines were detected in the cases with high procalcitonin concentration, whereas chlorinated phosphatidylcholines were undetected. The detections of oxidized phosphatidylcholines in human tissues might indicate previous exposure to hypochlorous acid in septic cases. Our results provide insight into the mechanisms underlying pathogen survival following inflammation associated with neutrophil activation and topical myeloperoxidase release and show postmortem biomarkers candidates for sepsis.


Assuntos
Abscesso/diagnóstico , Abscesso/metabolismo , Ácido Hipocloroso/metabolismo , Lipídeos/análise , Fosfatidilcolinas/metabolismo , Biomarcadores/metabolismo , Membrana Celular/metabolismo , Cromatografia Líquida , Medicina Legal/métodos , Halogenação , Humanos , Ácido Hipocloroso/química , Espectrometria de Massas , Ativação de Neutrófilo , Oxirredução , Peroxidase/metabolismo , Fosfatidilcolinas/química
7.
Proc Natl Acad Sci U S A ; 117(26): 15006-15017, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32554497

RESUMO

Cytochrome bo 3 ubiquinol oxidase is a transmembrane protein, which oxidizes ubiquinone and reduces oxygen, while pumping protons. Apart from its combination with F1Fo-ATPase to assemble a minimal ATP regeneration module, the utility of the proton pump can be extended to other applications in the context of synthetic cells such as transport, signaling, and control of enzymatic reactions. In parallel, polymers have been speculated to be phospholipid mimics with respect to their ability to self-assemble in compartments with increased stability. However, their usability as interfaces for complex membrane proteins has remained questionable. In the present work, we optimized a fusion/electroformation approach to reconstitute bo 3 oxidase in giant unilamellar vesicles made of PDMS-g-PEO and/or phosphatidylcholine (PC). This enabled optical access, while microfluidic trapping allowed for online analysis of individual vesicles. The tight polymer membranes and the inward oriented enzyme caused 1 pH unit difference in 30 min, with an initial rate of 0.35 pH·min-1 To understand the interplay in these composite systems, we studied the relevant mechanical and rheological membrane properties. Remarkably, the proton permeability of polymer/lipid hybrids decreased after protein insertion, while the latter also led to a 20% increase of the polymer diffusion coefficient in polymersomes. In addition, PDMS-g-PEO increased the activity lifetime and the resistance to free radicals. These advantageous properties may open diverse applications, ranging from cell-free biotechnology to biomedicine. Furthermore, the presented study serves as a comprehensive road map for studying the interactions between membrane proteins and synthetic membranes, which will be fundamental for the successful engineering of such hybrid systems.


Assuntos
Membrana Celular/enzimologia , Grupo dos Citocromos b/química , Proteínas de Escherichia coli/química , Escherichia coli/enzimologia , Membrana Celular/química , Membrana Celular/genética , Grupo dos Citocromos b/genética , Grupo dos Citocromos b/metabolismo , Transporte de Elétrons , Escherichia coli/química , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Fosfatidilcolinas/metabolismo , Polímeros/química , Prótons
8.
Nucleic Acids Res ; 48(11): 5967-5985, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32406921

RESUMO

During infection of a host, Pseudomonas aeruginosa orchestrates global gene expression to adapt to the host environment and counter the immune attacks. P. aeruginosa harbours hundreds of regulatory genes that play essential roles in controlling gene expression. However, their contributions to the bacterial pathogenesis remain largely unknown. In this study, we analysed the transcriptomic profile of P. aeruginosa cells isolated from lungs of infected mice and examined the roles of upregulated regulatory genes in bacterial virulence. Mutation of a novel regulatory gene pvrA (PA2957) attenuated the bacterial virulence in an acute pneumonia model. Chromatin immunoprecipitation (ChIP)-Seq and genetic analyses revealed that PvrA directly regulates genes involved in phosphatidylcholine utilization and fatty acid catabolism. Mutation of the pvrA resulted in defective bacterial growth when phosphatidylcholine or palmitic acid was used as the sole carbon source. We further demonstrated that palmitoyl coenzyme A is a ligand for the PvrA, enhancing the binding affinity of PvrA to its target promoters. An arginine residue at position 136 was found to be essential for PvrA to bind palmitoyl coenzyme A. Overall, our results revealed a novel regulatory pathway that controls genes involved in phosphatidylcholine and fatty acid utilization and contributes to the bacterial virulence.


Assuntos
Proteínas de Bactérias/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Genes Bacterianos/genética , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Animais , Arginina/metabolismo , Sequência de Bases , Imunoprecipitação da Cromatina , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Ligantes , Camundongos , Modelos Moleculares , Mutação , Ácido Palmítico/metabolismo , Palmitoil Coenzima A/metabolismo , Fosfatidilcolinas/metabolismo , Pneumonia Bacteriana/microbiologia , Regiões Promotoras Genéticas , Pseudomonas aeruginosa/genética , Transcriptoma , Virulência/genética
9.
Phys Chem Chem Phys ; 22(21): 12281-12293, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32432296

RESUMO

Carotenoids are pigment molecules that protect biomembranes against degradation and may be involved in the formation of functional bacterial membrane microdomains. Little is known on whether different types of carotenoids have different effects on the membrane or if there is any concentration dependence of these effects. In this work, we present results from molecular dynamics simulations of phospholipid bilayers containing different amounts of either ß-carotene or zeaxanthin. Both ß-carotene and zeaxanthin show the ability to laterally condense the membrane lipids and reduce their inter-leaflet interactions. With increasing concentrations, both carotenoids increase the bilayer thickness and rigidity. The results reveal that carotenoids have similar effects to cholesterol on regulating the behavior of fluid-phase membranes, suggesting that they could function as sterol substitutes and confirming their potential role in the formation of functional membrane domains.


Assuntos
Bicamadas Lipídicas/metabolismo , Zeaxantinas/metabolismo , beta Caroteno/metabolismo , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Zeaxantinas/química , beta Caroteno/química
10.
Am J Respir Cell Mol Biol ; 63(2): 219-233, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32315541

RESUMO

Pulmonary disease after World Trade Center particulate matter (WTC-PM) exposure is associated with dyslipidemia and the receptor for advanced glycation end products (RAGE); however, the mechanisms are not well understood. We used a murine model and a multiomics assessment to understand the role of RAGE in the pulmonary long-term effects of a single high-intensity exposure to WTC-PM. After 1 month, WTC-PM-exposed wild-type (WT) mice had airway hyperreactivity, whereas RAGE-deficient (Ager-/-) mice were protected. PM-exposed WT mice also had histologic evidence of airspace disease, whereas Ager-/- mice remained unchanged. Inflammatory mediators such as G-CSF (granulocyte colony-stimulating factor), IP-10 (IFN-γ-induced protein 10), and KC (keratinocyte chemoattractant) were differentially expressed after WTC-PM exposure. WTC-PM induced α-SMA, DIAPH1 (protein diaphanous homolog 1), RAGE, and significant lung collagen deposition in WT compared with Ager-/- mice. Compared with WT mice with PM exposure, relative expression of phosphorylated to total CREB (cAMP response element-binding protein) and JNK (c-Jun N-terminal kinase) was significantly increased in the lung of PM-exposed Ager-/- mice, whereas Akt (protein kinase B) was decreased. Random forests of the refined lung metabolomic profile classified subjects with 92% accuracy; principal component analysis captured 86.7% of the variance in three components and demonstrated prominent subpathway involvement, including known mediators of lung disease such as vitamin B6 metabolites, sphingolipids, fatty acids, and phosphatidylcholines. Treatment with a partial RAGE antagonist, pioglitazone, yielded similar fold-change expression of metabolites (N6-carboxymethyllysine, 1-methylnicotinamide, N1+N8-acetylspermidine, and succinylcarnitine [C4-DC]) between WT and Ager-/- mice exposed to WTC-PM. RAGE can mediate WTC-PM-induced airway hyperreactivity and warrants further investigation.


Assuntos
Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Material Particulado/efeitos adversos , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Hipersensibilidade Respiratória/induzido quimicamente , Hipersensibilidade Respiratória/metabolismo , Poluentes Atmosféricos/efeitos adversos , Animais , Asma/induzido quimicamente , Asma/metabolismo , Hiper-Reatividade Brônquica/induzido quimicamente , Hiper-Reatividade Brônquica/metabolismo , Líquido da Lavagem Broncoalveolar , Modelos Animais de Doenças , Poeira , Explosões , Ácidos Graxos/metabolismo , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Fosfatidilcolinas/metabolismo , Ataques Terroristas de 11 de Setembro , Esfingolipídeos/metabolismo , Vitamina B 6/metabolismo
11.
PLoS One ; 15(4): e0231289, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32287294

RESUMO

Breast cancer (BC) is the most prevalent type of cancer in women in western countries. BC mortality has not declined despite early detection by screening, indicating the need for better informed treatment decisions. Therefore, a novel noninvasive diagnostic tool for BC would give the opportunity of subtype-specific treatment and improved prospects for the patients. Heterogeneity of BC tumor subtypes is reflected in the expression levels of enzymes in lipid metabolism. The aim of the study was to investigate whether the subtype defined by the transcriptome is reflected in the lipidome of BC cell lines. A liquid chromatography mass spectrometry (LC-MS) platform was applied to analyze the lipidome of six cell lines derived from human BC cell lines representing different BC subtypes. We identified an increased abundance of triacylglycerols (TG) ≥ C-48 with moderate or multiple unsaturation in fatty acyl chains and down-regulated ether-phosphatidylethanolamines (PE) (C-34 to C-38) in cell lines representing estrogen receptor and progesterone receptor positive tumor subtypes. In a cell line representing HER2-overexpressing tumor subtype an elevated expression of TG (≤ C-46), phosphatidylcholines (PC) and PE containing short-chained (≤ C-16) saturated or monounsaturated fatty acids were observed. Increased abundance of PC ≥ C-40 was found in cell lines of triple negative BC subtype. In addition, differences were detected in lipidomes within these previously defined subtypes. We conclude that subtypes defined by the transcriptome are indeed reflected in differences in the lipidome and, furthermore, potentially biologically relevant differences may exist within these defined subtypes.


Assuntos
Neoplasias da Mama/classificação , Neoplasias da Mama/metabolismo , Metabolismo dos Lipídeos , Lipidômica/métodos , Linhagem Celular Tumoral , Feminino , Humanos , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Triglicerídeos/metabolismo
12.
Sci Rep ; 10(1): 5576, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32221338

RESUMO

Lipids play a significant role in regulation of health and disease. To enhance our understanding of the role of lipids in regulation of lifespan and healthspan additional studies are required. Here, UHPLC-MS/MS lipidomics was used to measure dynamic changes in lipid composition as a function of age and gender in genetically identical male and female Daphnia magna with different average lifespans. We demonstrate statistically significant age-related changes in triglycerides (TG), diglycerides (DG), phosphatidylcholine, phosphatidylethanolamine, ceramide and sphingomyelin lipid groups, for example, in males, 17.04% of TG lipid species decline with age whilst 37.86% increase in relative intensity with age. In females, 23.16% decrease and 25.31% increase in relative intensity with age. Most interestingly, the rate and direction of change can differ between genetically identical female and male Daphnia magna, which could be the cause and/or the consequence of the different average lifespans between the two genetically identical genders. This study provides a benchmark dataset to understand how lipids alter as a function of age in genetically identical female and male species with different average lifespan and ageing rate.


Assuntos
Envelhecimento/metabolismo , Daphnia/metabolismo , Daphnia/fisiologia , Metabolismo dos Lipídeos/fisiologia , Longevidade/fisiologia , Animais , Diglicerídeos/metabolismo , Feminino , Masculino , Fosfatidilcolinas/metabolismo , Esfingomielinas/metabolismo , Triglicerídeos/metabolismo
13.
Phys Rev Lett ; 124(10): 108102, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32216409

RESUMO

Lipid rafts serve as anchoring platforms for membrane proteins. Thus far they escaped direct observation by light microscopy due to their small size. Here we used differently colored dyes as reporters for the registration of both ordered and disordered lipids from the two leaves of a freestanding bilayer. Photoswitchable lipids dissolved or reformed the domains. Measurements of domain mobility indicated the presence of 120 nm wide ordered and 40 nm wide disordered domains. These sizes are in line with the predicted roles of line tension and membrane undulation as driving forces for alignment.


Assuntos
Lipídeos de Membrana/administração & dosagem , Microdomínios da Membrana/química , Colesterol/química , Colesterol/metabolismo , Diglicerídeos/química , Diglicerídeos/metabolismo , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Microdomínios da Membrana/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Microscopia Confocal/métodos , Modelos Químicos , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Espectrometria de Fluorescência/métodos
14.
Proc Natl Acad Sci U S A ; 117(14): 8032-8043, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32193339

RESUMO

Ehrlichia chaffeensis, a cholesterol-rich and cholesterol-dependent obligate intracellular bacterium, partially lacks genes for glycerophospholipid biosynthesis. We found here that E. chaffeensis is dependent on host glycerolipid biosynthesis, as an inhibitor of host long-chain acyl CoA synthetases, key enzymes for glycerolipid biosynthesis, significantly reduced bacterial proliferation. E. chaffeensis cannot synthesize phosphatidylcholine or cholesterol but encodes enzymes for phosphatidylethanolamine (PE) biosynthesis; however, exogenous NBD-phosphatidylcholine, Bodipy-PE, and TopFluor-cholesterol were rapidly trafficked to ehrlichiae in infected cells. DiI (3,3'-dioctadecylindocarbocyanine)-prelabeled host-cell membranes were unidirectionally trafficked to Ehrlichia inclusion and bacterial membranes, but DiI-prelabeled Ehrlichia membranes were not trafficked to host-cell membranes. The trafficking of host-cell membranes to Ehrlichia inclusions was dependent on both host endocytic and autophagic pathways, and bacterial protein synthesis, as the respective inhibitors blocked both infection and trafficking of DiI-labeled host membranes to Ehrlichia In addition, DiI-labeled host-cell membranes were trafficked to autophagosomes induced by the E. chaffeensis type IV secretion system effector Etf-1, which traffic to and fuse with Ehrlichia inclusions. Cryosections of infected cells revealed numerous membranous vesicles inside inclusions, as well as multivesicular bodies docked on the inclusion surface, both of which were immunogold-labeled by a GFP-tagged 2×FYVE protein that binds to phosphatidylinositol 3-phosphate. Focused ion-beam scanning electron microscopy of infected cells validated numerous membranous structures inside bacteria-containing inclusions. Our results support the notion that Ehrlichia inclusions are amphisomes formed through fusion of early endosomes, multivesicular bodies, and early autophagosomes induced by Etf-1, and they provide host-cell glycerophospholipids and cholesterol that are necessary for bacterial proliferation.


Assuntos
Ehrlichia chaffeensis/metabolismo , Ehrlichiose/patologia , Corpos de Inclusão/metabolismo , Fosfatidilcolinas/metabolismo , Vacúolos/microbiologia , Animais , Autofagossomos/metabolismo , Membrana Celular/metabolismo , Cães , Ehrlichia chaffeensis/citologia , Ehrlichia chaffeensis/patogenicidade , Ehrlichiose/sangue , Ehrlichiose/microbiologia , Endossomos/metabolismo , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Corpos de Inclusão/ultraestrutura , Microscopia Intravital , Microscopia Eletrônica de Varredura , Células THP-1 , Imagem com Lapso de Tempo , Vacúolos/ultraestrutura
15.
Biomed Res Int ; 2020: 5393041, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32149115

RESUMO

Resveratrol (Resv) offers health benefits in cancer and has been reported to modulate important enzymes of lipid metabolism. Studies of its effects on lipid composition in different subtypes of breast-cancer cells are scarce. Thus, we investigated the alterations in phospholipids (PL), fatty acids (FA), and lipid metabolism enzymes in two breast-cancer cell lines after Resv treatment. MCF-7 and MDA-MB-231 cells were treated with 80 and 200 µM of Resv, respectively, for 24 hours. We analyzed PL with radiolabeled inorganic phosphate (32Pi) by thin-layer chromatography, FA by gas chromatography-mass spectrometry, and lipid metabolism enzymes (DGAT2, FAS, ρACCß, pAMPKα, and AMPK) by Western blot. Resv treated MDA-MB-231 phospholipids showed a reduction in phosphatidylcholine (63%) and phosphatidylethanolamine (35%). We observed an increase in eicosapentaenoic acid (EPA) (73%) and docosahexaenoic acid (DHA) (65%) in MCF-7 cells after Resv treatment. Interestingly, the same treatment caused 50% and 90% increases in EPA and DHA, respectively, in MDA-MB-231 cells. In MCF-7 cells, Resv increased the expression of ρACCß (3.3-fold) and AMPKα/ρAMPKα (1.5-fold) and in MDA-MB-231 cells it inhibited the expression of ρACCß (111.8-fold) and AMPKα/ρAMPKα (1.2 fold). Our results show that Resv modified PL and saturated and unsaturated FA especially in MDA-MB-231 cells, and open new perspectives to the understanding of the reported anticancer effect of Resv on these cells.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Metabolismo dos Lipídeos/efeitos dos fármacos , Resveratrol/farmacologia , Proteínas Quinases Ativadas por AMP/metabolismo , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Ácidos Docosa-Hexaenoicos/metabolismo , Ácido Eicosapentaenoico/análogos & derivados , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados , Feminino , Humanos , Lipídeos/análise , Células MCF-7 , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Fosfolipídeos/metabolismo , Resveratrol/uso terapêutico
16.
Int J Mol Sci ; 21(3)2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32023864

RESUMO

Brain aging involves changes in the lipid membrane composition that lead to a decrease in membrane excitability and neurotransmitter release. These membrane modifications have been identified as contributing factors in age-related memory decline. In this sense, precursors of phospholipids (PLs) can restore the physiological composition of cellular membranes and produce valuable therapeutic effects in brain aging. Among promising drugs, alpha-glycerylphosphorylethanolamine (GPE) has demonstrated protective effects in amyloid-injured astrocytes and in an aging model of human neural stem cells. However, the compound properties on mature neuronal cells remain unexplored. Herein, GPE was tested in human hippocampal neurons, which are involved in learning and memory, and characterized by a functional cholinergic transmission, thus representing a valuable cellular model to explore the beneficial properties of GPE. GPE induced the release of the main membrane phospholipids and of the acetylcholine neurotransmitter. Moreover, the compound reduced lipid peroxidation and enhanced membrane fluidity of human brain cells. GPE counteracted the DNA damage and viability decrease observed in in vitro aged neurons. Among GPE treatment effects, the autophagy was found positively upregulated. Overall, these results confirm the beneficial effects of GPE treatment and suggest the compound as a promising drug to preserve hippocampal neurons and virtually memory performances.


Assuntos
Hipocampo/citologia , Fármacos Neuroprotetores/farmacologia , Nootrópicos/farmacologia , Fosfatidiletanolaminas/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Modelos Biológicos , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo
17.
Sci Rep ; 10(1): 1837, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-32020000

RESUMO

Liposomes or biological vesicles can be created from cholesterol, phospholipid, and water. Their stability is affected by their phospholipid composition which can influence disease treatment and drug delivery efficacy. In this study, the effect of phospholipid type on the formation and stability of liposomes using coarse-grained molecular dynamics simulations is investigated. For this purpose, the simulation study of the DSPC (1,2-distearoyl-sn-glycero-3-phosphocholine) and DPSM (Egg sphingomyelin) lipids were considered. All simulations were carried out using the Gromacs software and Martini force field 2.2. Energy minimization (3000 steps) model, equilibrium at constant volume to adjust the temperature at 400 Kelvin and equilibrium at constant pressure to adjust the pressure, at atmospheric pressure (1 bar) have been validated. Microsecond simulations, as well as formation analysis including density, radial distribution function, and solvent accessible surface area, demonstrated spherical nanodisc structures for the DPSM and DSPC liposomes. The results revealed that due to the cylindrical geometric structure and small-size head group, the DSPC lipid maintained its perfectly spherical structure. However, the DPSM lipid showed a conical geometric structure with larger head group than other lipids, which allows the liposome to form a micelle structure. Although the DSPC and DPSM lipids used in the laboratory tests exhibit liposome and micelle behaviors, the simulation results revealed their nanodisc structures. Energy analysis including overall energy, Van der Waals interaction energy, and electrostatic interaction energy showed that DPSM liposome is more stable than DSPC liposome.


Assuntos
Lipossomos/metabolismo , Fosfatidilcolinas/metabolismo , Esfingomielinas/metabolismo , Pressão do Ar , Metabolismo Energético , Nanoestruturas , Eletricidade Estática , Temperatura
18.
PLoS One ; 15(2): e0228279, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027677

RESUMO

Smoke exposure is known to decrease total pulmonary surfactant and alter its composition, but the role of surfactant in chronic obstructive pulmonary disease (COPD) remains unknown. We aimed to analyze the compositional changes in the surfactant lipidome in COPD and identify specific lipids associated with pulmonary function decline. Bronchoalveolar lavage (BAL) fluid was obtained from 12 former smokers with COPD and 5 non-smoking, non-asthmatic healthy control volunteers. Lipids were extracted and analyzed by liquid chromatography and mass spectrometry. Pulmonary function data were obtained by spirometry, and correlations of lung function with lipid species were determined. Wild-type C57BL/6 mice were exposed to 6 months of second-hand smoke in a full-body chamber. Surfactant lipids were decreased by 60% in subjects with COPD. All phospholipid classes were dramatically decreased, including ether phospholipids, which have not been studied in pulmonary surfactant. Availability of phospholipid, cholesterol, and sphingomyelin in BAL strongly correlated with pulmonary function and this was attributable to specific lipid species of phosphatidylcholine with surface tension reducing properties, and of phosphatidylglycerol with antimicrobial roles, as well as to other less studied lipid species. Mice exposed to smoke for six months recapitulated surfactant lipidomic changes observed in human subjects with COPD. In summary, we show that the surfactant lipidome is substantially altered in subjects with COPD, and decreased availability of phospholipids correlated with decreased pulmonary function. Further investigation of surfactant alterations in COPD would improve our understanding of its physiopathology and reveal new potential therapeutic targets.


Assuntos
Lipídeos/análise , Pulmão/metabolismo , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Surfactantes Pulmonares/metabolismo , Idoso , Animais , Líquido da Lavagem Broncoalveolar/química , Estudos de Casos e Controles , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Humanos , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Fosfolipídeos/química , Fosfolipídeos/metabolismo , Fumantes , Poluição por Fumaça de Tabaco
19.
J Gastroenterol Hepatol ; 35(8): 1437-1448, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32030821

RESUMO

BACKGROUND AND AIM: Aging is an independent risk factor for the progression of non-alcoholic steatohepatitis. Here, we investigated the role of age-related alterations in fatty acid metabolism in dietary steatohepatitis using lipidomics analysis. METHODS: Male 8-week and 55-week-old C57BL/6 J mice were fed a high-fat diet (HFD) for 8 weeks. The quality and quantity of lipid molecular species in the liver were evaluated using the lipidomics approach. RESULTS: Elder mice fed an HFD developed more severe steatohepatitis than young mice. Oxidative stress and inflammatory cytokines in the liver were exacerbated following HFD feeding in elder mice compared with young mice. In elder mice, de novo fatty acid synthesis was promoted, whereas ß oxidation was blunted following HFD feeding, and lipid secretion from the liver was reduced. The expression of sirtuin 1 was not only reduced with age as expected but also significantly decreased due to intake of HFD. In the lipidomics analysis, the concentrations of diacylglycerol and TAG molecular species containing monounsaturated fatty acids were markedly increased following HFD feeding in elder mice compared with young mice. In contrast, the concentration of phosphatidylethanolamine and phosphatidylcholine molecular species containing polyunsaturated fatty acids were remarkably decreased following HFD feeding in elder mice compared with young mice, and the expression of fatty acid desaturase was blunted. CONCLUSIONS: Aging-dependent alterations in lipid metabolism under excessive lipid supply most likely enhance hepatic lipotoxicity, thereby exacerbating metabolic steatohepatitis in elderly.


Assuntos
Envelhecimento/metabolismo , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/etiologia , Fígado Gorduroso/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Animais , Diglicerídeos/metabolismo , Progressão da Doença , Ácidos Graxos Monoinsaturados/metabolismo , Ácidos Graxos Insaturados/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Sirtuína 1/metabolismo
20.
J Mol Biol ; 432(7): 1978-1995, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32035904

RESUMO

Serum amyloid A (SAA) is a plasma protein that transports lipids during inflammation. To explore SAA solution conformations and lipid-binding mechanism, we used hydrogen-deuterium exchange mass spectrometry, lipoprotein reconstitution, amino acid sequence analysis, and molecular dynamics simulations. Solution conformations of lipid-bound and lipid-free mSAA1 at pH~7.4 agreed in details with the crystal structures but also showed important differences. The results revealed that amphipathic α-helices h1 and h3 comprise a lipid-binding site that is partially pre-formed in solution, is stabilized upon binding lipids, and shows lipid-induced folding of h3. This site sequesters apolar ligands via a concave hydrophobic surface in SAA oligomers. The largely disordered/dynamic C-terminal region is conjectured to mediate the promiscuous binding of other ligands. The h1-h2 linker region is predicted to form an unexpected ß-hairpin that may represent an early amyloidogenic intermediate. The results help establish structural underpinnings for understanding SAA interactions with its key functional ligands, its evolutional conservation, and its transition to amyloid.


Assuntos
Fosfatidilcolinas/metabolismo , Conformação Proteica , Proteína Amiloide A Sérica/química , Proteína Amiloide A Sérica/metabolismo , Animais , Sítios de Ligação , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Camundongos , Simulação de Dinâmica Molecular , Dobramento de Proteína
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA