RESUMO
AIMS: Improving the composition of circulating fatty acids (FA) leads to a reduction in cardiovascular diseases (CVD) in high-risk individuals. The membrane fluidity of red blood cells (RBC), which reflects circulating FA status, may be a valid biomarker of cardiovascular (CV) risk in type 2 diabetes (T2D). METHODS: Red blood cell membrane fluidity, quantified as general polarization (GP), was assessed in 234 subjects with T2D, 86 with prior major CVD. Based on GP distribution, a cut-off of .445 was used to divide the study cohort into two groups: the first with higher GP, called GEL, and the second, defined as lower GP (LGP). Lipidomic analysis was performed to evaluate FA composition of RBC membranes. RESULTS: Although with comparable CV risk factors, the LGP group had a greater percentage of patients with major CVD than the GEL group (40% vs 24%, respectively, p < .05). Moreover, in a logistic regression analysis, a lower GP value was independently associated with the presence of macrovascular complications. Lipidomic analysis showed a clear shift of LGP membranes towards a pro-inflammatory condition due to higher content of arachidonic acid and increased omega 6/omega 3 index. CONCLUSIONS: Increased membrane fluidity is associated with a higher CV risk in subjects with T2D. If confirmed in prospective studies, membrane fluidity could be a new biomarker for residual CV risk assessment in T2D.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Humanos , Membrana Eritrocítica/metabolismo , Fluidez de Membrana , Estudos Prospectivos , Fatores de Risco , Eritrócitos/metabolismo , Ácidos Graxos/metabolismo , Fatores de Risco de Doenças Cardíacas , Biomarcadores/metabolismoRESUMO
Peanut allergy is a lifelong, increasingly prevalent, and potentially life-threatening disease burdening families and communities. Dietary, particularly polyunsaturated fatty acids (PUFAs), intakes can exert positive effects on immune and inflammatory responses, and the red blood cell (RBC) membrane lipidome contains stabilized metabolic and nutritional information connected with such responses. The fatty-acid-based membrane lipidome profile has been exploratorily evaluated in a small cohort of patients (eight males and one female, age range 4.1−21.7 years old, body mass index BMI < 25) with angioedema and/or anaphylaxis after peanut ingestion. This analysis was performed according to an ISO 17025 certified robotic protocol, isolating mature RBCs, extracting membrane lipids, and transforming them to fatty acid methyl esters for gas chromatography recognition and quantification. Comparison with a group of age- and BMI-matched healthy individuals and with benchmark interval values of a healthy population evidenced significant differences, such as higher levels of ω-6 (arachidonic acid), lower values of ω-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), together with an increased ω-6/ω-3 ratio in allergic patients. A significant inverse correlation was also found between specific immunoglobulin E (IgE) levels and ω-6 di-homo-gamma-linolenic acid (DGLA) and total PUFAs. Results of this preliminary study encourage screenings in larger cohorts, also in view of precision nutrition and nutraceuticals strategies, and stimulate interest to expand basic and applied research for unveiling molecular mechanisms that are still missing and individuating treatments in chronic allergic disorders.
Assuntos
Ácidos Graxos Ômega-3 , Hipersensibilidade a Amendoim , Masculino , Humanos , Feminino , Pré-Escolar , Criança , Adolescente , Adulto Jovem , Adulto , Ácidos Graxos , Lipidômica , Ácido Eicosapentaenoico/metabolismo , Ácidos Docosa-Hexaenoicos/metabolismoRESUMO
Fatty acids have an important place in both biological and nutritional contexts and, from a clinical point of view, they have known consequences for diseases' onset and development, including cancer. The use of fatty acid-based food and nutraceuticals to support cancer therapy is a multidisciplinary subject, involving molecular and clinical research. Knowledge regarding polyunsaturated fatty acids essentiality/oxidizability and the role of lipogenesis-desaturase pathways for cell growth, as well as oxidative reactivity in cancer cells, are discussed, since they can drive the choice of fatty acids using their multiple roles to support antitumoral drug activity. The central role of membrane fatty acid composition is highlighted for the application of membrane lipid therapy. As fatty acids are also known as biomarkers of cancer onset and progression, the personalization of the fatty acid-based therapy is also possible, taking into account other important factors such as formulation, bioavailability and the distribution of the supplementation. A holistic approach emerges combining nutra- and pharma-strategies in an appropriate manner, to develop further knowledge and applications in cancer therapy.
Assuntos
Ácidos Graxos , Neoplasias , Suplementos Nutricionais , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados/metabolismo , Humanos , Lipídeos de Membrana , Neoplasias/tratamento farmacológicoRESUMO
This work intends to describe the physical properties of red blood cell (RBC) membranes in obese adults. The hypothesis driving this research is that obesity, in addition to increasing the amount of body fat, will also modify the lipid composition of membranes in cells other than adipocytes. Forty-nine control volunteers (16 male, 33 female, BMI 21.8 ± 5.6 and 21.5 ± 4.2 kg/m2, respectively) and 52 obese subjects (16 male and 36 female, BMI 38.2± 11.0 and 40.7 ± 8.7 kg/m2, respectively) were examined. The two physical techniques applied were atomic force microscopy (AFM) in the force spectroscopy mode, which allows the micromechanical measurement of penetration forces, and fluorescence anisotropy of trimethylammonium diphenylhexatriene (TMA-DPH), which provides information on lipid order at the membrane polar-nonpolar interface. These techniques, in combination with lipidomic studies, revealed a decreased rigidity in the interfacial region of the RBC membranes of obese as compared to control patients, related to parallel changes in lipid composition. Lipidomic data show an increase in the cholesterol/phospholipid mole ratio and a decrease in sphingomyelin contents in obese membranes. ω-3 fatty acids (e.g., docosahexaenoic acid) appear to be less prevalent in obese patient RBCs, and this is the case for both the global fatty acid distribution and for the individual major lipids in the membrane phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS). Moreover, some ω-6 fatty acids (e.g., arachidonic acid) are increased in obese patient RBCs. The switch from ω-3 to ω-6 lipids in obese subjects could be a major factor explaining the higher interfacial fluidity in obese patient RBC membranes.
Assuntos
Difenilexatrieno/análogos & derivados , Membrana Eritrocítica/fisiologia , Lipidômica/métodos , Obesidade/diagnóstico por imagem , Adolescente , Adulto , Fenômenos Biomecânicos , Estudos de Casos e Controles , Difenilexatrieno/administração & dosagem , Membrana Eritrocítica/metabolismo , Feminino , Polarização de Fluorescência , Humanos , Masculino , Microscopia de Força Atômica , Pessoa de Meia-Idade , Obesidade/metabolismo , Obesidade/fisiopatologia , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Fosfatidilserinas/metabolismo , Adulto JovemRESUMO
Reductive radical stress represents the other side of the redox spectrum, less studied but equally important compared to oxidative stress. The reactivity of hydrogen atoms (Hâ¢) and hydrated electrons (e-aq) connected with peptides/proteins is summarized, focusing on the chemical transformations of methionine (Met) and cystine (CysS-SCys) residues into α-aminobutyric acid and alanine, respectively. Chemical and mechanistic aspects of desulfurization processes with formation of diffusible sulfur-centered radicals, such as methanethiyl (CH3Sâ¢) and sulfhydryl (HSâ¢) radicals, are discussed. These findings are further applied to biomimetic radical chemistry, modeling the occurrence of tandem protein-lipid damages in proteo-liposomes and demonstrating that generation of sulfur-centered radicals from a variety of proteins is coupled with the cis-trans isomerization of unsaturated lipids in membranes. Recent applications to pharmaceutical and pharmacological contexts are described, evidencing novel perspectives in the stability of formulations and mode of action of drugs, respectively.
Assuntos
Aminoácidos Sulfúricos/metabolismo , Proteínas/metabolismo , Estresse Fisiológico , Animais , Radicais Livres/metabolismo , Raios gama , Humanos , OxirreduçãoRESUMO
The conversion of ribonucleosides to 2'-deoxyribonucleosides is catalyzed by ribonucleoside reductase enzymes in nature. One of the key steps in this complex radical mechanism is the reduction of the 3'-ketodeoxynucleotide by a pair of cysteine residues, providing the electrons via a disulfide radical anion (RSSRâ¢-) in the active site of the enzyme. In the present study, the bioinspired conversion of ketones to corresponding alcohols was achieved by the intermediacy of disulfide radical anion of cysteine (CysSSCys)â¢- in water. High concentration of cysteine and pH 10.6 are necessary for high-yielding reactions. The photoinitiated radical chain reaction includes the one-electron reduction of carbonyl moiety by disulfide radical anion, protonation of the resulting ketyl radical anion by water, and H-atom abstraction from CysSH. The (CysSSCys)â¢- transient species generated by ionizing radiation in aqueous solutions allowed the measurement of kinetic data with ketones by pulse radiolysis. By measuring the rate of the decay of (CysSSCys)â¢- at λmax = 420 nm at various concentrations of ketones, we found the rate constants of three cyclic ketones to be in the range of 104-105 M-1s-1 at ~22 °C.
Assuntos
Biomimética , Dissulfetos , Cetonas , Radical Hidroxila/química , Cinética , ÁguaRESUMO
Bleomycin has a long-studied mechanism of action through the formation of a complex with metals, such as iron. The bleomycin-iron complex was recently shown to induce membrane damage by free radical reactivity. Because the use of Fe nanoparticles is spreading for drug delivery strategies, molecular mechanisms of cell damage must include different compartments in order to observe the progression of the cell reactivity. In this study, human embryonic kidney (HEK-293) cells were exposed for 24 h to bleomycin and polymeric iron oxide nanoparticles (Fe-NPs), alone or in combination. The fatty acid-based membrane lipidomic analysis evidenced the fatty acid remodeling in response to the treatments. Bleomycin alone caused the increase of saturated fatty acid (SFA) moieties in cell membrane glycerophospholipids with concomitant diminution of monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid levels. Under Fe-NPs treatment, omega-6 PUFA decreased and trans fatty acid isomers increased. Under coadministration bleomycin and Fe-NPs, all membrane remodeling changes disappeared compared to those of the controls, with only an increase of omega-6 PUFA that elevates peroxidation index remaining. Our results highlight the important role of fatty-acid-based membrane lipidome monitoring to follow up the fatty acid reorganization induced by the drug, to be considered as a side effect of the pharmacological activity, suggesting the need of an integrated approach for the investigation of drug and carrier molecular mechanisms.
Assuntos
Bleomicina/farmacologia , Ácidos Graxos/metabolismo , Compostos Férricos/farmacologia , Glicerofosfolipídeos/metabolismo , Nanopartículas/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Células Cultivadas , Células HEK293 , HumanosRESUMO
This review is an update on tris(trimethylsilyl)silane, TTMSS, in organic chemistry, focusing on the advancements of the past decade. The overview includes a wide range of chemical processes and synthetic strategies under different experimental conditions, including functional group insertion and transformations, as well as preparation of complex molecules, natural products, polymers, surfaces, and new materials. These results reveal how TTMSS has matured over the past 30 years, and they further establish its value as a free radical reagent with widespread academic and industrial applications.
RESUMO
Breast cancer is a worldwide commonly found malignancy in women and effective treatment is regarded as a huge clinical challenge even in the presence of several treatment options. Extensive literature is available demonstrating polyphenols as phytopharmaceutical anticancer agents. Among the polyphenols, quercetin and curcumin have been reported to have a strong potential against breast cancer. However, so far, no comprehensive study has been performed to demonstrate the anticarcinogenic effects of curcumin, quercetin, and their combinations with somatostatin on the fatty acid profile of breast cancer cell membranes. We used MCF-7 and MDA-MB231 breast cancer cells incubated with curcumin and quercetin for 24 h, in the absence and presence of somatostatin, at their EC50 concentrations to evaluate membrane fatty acid based functional lipidomics together with the followup of EGFR and MAPK signaling pathways. The two cell lines gave different membrane free fatty acid reorganization. In MCF-7 cells, the following changes were observed: an increase of ω6 linoleic acid in the cells incubated with somatostatin + quercetin and quercetin and a decrease of ω3 acids in the cells incubated with somatostatin + curcumin compared to somatostatin and significant increases of monounsaturated fatty acid (MUFA), mono-trans arachidonic acid levels and docosapentaenoic acid for the cells incubated with somatostatin + quercetin compared to the control cells. In MDA-MB231 cells, incubations with curcumin, quercetin, and somatostatin + quercetin induced the most significant membrane remodeling with the increase of stearic acid, diminution of ω6 linoleic, arachidonic acids, and ω3 (docosapentaenoic and docosahexaenoic acids). Distinct signaling pathway changes were found for these cell lines. In MCF-7 cells, separate or combined incubations with somatostatin and quercetin, significantly decreased EGFR and incubation with curcumin decreased MAPK signaling. In MDA-MB231 cells, incubation with curcumin decreased AKT1 and p-AKT1 (Thr308) levels. Incubation with curcumin and quercetin decreased the EGFR levels. Our results showed that cytostatic and antioxidant treatments can be combined to induce membrane fatty acid changes, including lipid isomerization as specific free radical driven process, and to influence signaling pathways. This study aimed to contribute to the literature on these antioxidants in the treatment of breast cancer to clarify the effects and mechanisms in combination with somatostatin.
Assuntos
Neoplasias da Mama/metabolismo , Membrana Celular/metabolismo , Curcumina/farmacologia , Ácidos Graxos/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Quercetina/farmacologia , Somatostatina/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Membrana Celular/efeitos dos fármacos , Feminino , Hormônios/farmacologia , Humanos , Células Tumorais CultivadasRESUMO
Membrane microdomains that include lipid rafts, are involved in key physiological and pathological processes and participate in the entry of endocellular pathogens. These assemblies, enriched in cholesterol and sphingolipids, form highly dynamic, liquid-ordered phases that can be separated from the bulk membranes thanks to their resistance to solubilization by nonionic detergents. To characterize complexity and dynamics of detergent-resistant membranes of sexual stages of the rodent malaria parasite Plasmodium berghei, here we propose an integrated study of raft components based on proteomics, lipid analysis and bioinformatics. This analysis revealed unexpected heterogeneity and unexplored pathways associated with these specialized assemblies. Protein-protein relationships and protein-lipid co-occurrence were described through multi-component networks. The proposed approach can be widely applied to virtually every cell type in different contexts and perturbations, under physiological and/or pathological conditions.
Assuntos
Estágios do Ciclo de Vida/fisiologia , Malária/parasitologia , Microdomínios da Membrana/metabolismo , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/metabolismo , Animais , Colesterol/química , Colesterol/metabolismo , Simulação por Computador , Detergentes/química , Modelos Animais de Doenças , Gametogênese/fisiologia , Humanos , Lipídeos/análise , Microdomínios da Membrana/química , Camundongos , Camundongos Endogâmicos BALB C , Proteômica , Esfingolipídeos/química , Esfingolipídeos/metabolismoRESUMO
Palmitic acid metabolism involves delta-9 and delta-6 desaturase enzymes forming palmitoleic acid (9cis-16:1; n-7 series) and sapienic acid (6cis-16:1; n-10 series), respectively. The corresponding biological consequences and lipidomic research on these positional monounsaturated fatty acid (MUFA) isomers are under development. Furthermore, sapienic acid can bring to the de novo synthesis of the n-10 polyunsaturated fatty acid (PUFA) sebaleic acid (5cis,8cis-18:2), but such transformations in cancer cells are not known. The model of Caco-2 cell line was used to monitor sapienic acid supplementation (150 and 300 µM) and provide evidence of the formation of n-10 fatty acids as well as their incorporation at levels of membrane phospholipids and triglycerides. Comparison with palmitoleic and palmitic acids evidenced that lipid remodelling was influenced by the type of fatty acid and positional isomer, with an increase of 8cis-18:1, n-10 PUFA and a decrease of saturated fats in case of sapienic acid. Cholesteryl esters were formed only in cases with sapienic acid. Sapienic acid was the less toxic among the tested fatty acids, showing the highest EC50s and inducing death only in 75% of cells at the highest concentration tested. Two-photon fluorescent microscopy with Laurdan as a fluorescent dye provided information on membrane fluidity, highlighting that sapienic acid increases the distribution of fluid regions, probably connected with the formation of 8cis-18:1 and the n-10 PUFA in cell lipidome. Our results bring evidence for MUFA positional isomers and de novo PUFA synthesis for developing lipidomic analysis and cancer research.
Assuntos
Neoplasias do Colo/metabolismo , Ácidos Graxos Ômega-3/metabolismo , Ácidos Palmíticos/metabolismo , Fosfolipídeos/química , Células CACO-2 , Membrana Celular/química , Membrana Celular/metabolismo , Ésteres do Colesterol/biossíntese , Ésteres do Colesterol/química , Ésteres do Colesterol/metabolismo , Neoplasias do Colo/química , Neoplasias do Colo/patologia , Ácidos Graxos Monoinsaturados/química , Ácidos Graxos Monoinsaturados/farmacologia , Ácidos Graxos Ômega-3/biossíntese , Humanos , Ácidos Linoleicos/química , Ácidos Linoleicos/metabolismo , Ácidos Linoleicos/farmacologia , Linoleoil-CoA Desaturase/química , Microscopia de Fluorescência , Ácido Palmítico/química , Ácido Palmítico/metabolismo , Ácidos Palmíticos/química , Ácidos Palmíticos/farmacologia , Fosfolipídeos/biossínteseRESUMO
Modern omics techniques reveal molecular structures and cellular networks of tissues and cells in unprecedented detail. Recent advances in single cell analysis have further revolutionized all disciplines in cellular and molecular biology. These methods have also been employed in current investigations on the structure and function of insulin secreting beta cells under normal and pathological conditions that lead to an impaired glucose tolerance and type 2 diabetes. Proteomic and transcriptomic analyses have pointed to significant alterations in protein expression and function in beta cells exposed to diabetes like conditions (e.g., high glucose and/or saturated fatty acids levels). These nutritional overload stressful conditions are often defined as glucolipotoxic due to the progressive damage they cause to the cells. Our recent studies on the rat insulinoma-derived INS-1E beta cell line point to differential effects of such conditions in the phospholipid bilayers in beta cells. This review focuses on confocal microscopy-based detection of these profound alterations in the plasma membrane and membranes of insulin granules and lipid droplets in single beta cells under such nutritional load conditions.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Ácidos Graxos/metabolismo , Intolerância à Glucose/metabolismo , Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Animais , Linhagem Celular Tumoral , Membrana Celular/química , Membrana Celular/metabolismo , Grânulos Citoplasmáticos/metabolismo , Grânulos Citoplasmáticos/patologia , Diabetes Mellitus Tipo 2/fisiopatologia , Glucose/farmacologia , Intolerância à Glucose/fisiopatologia , Humanos , Células Secretoras de Insulina/química , Células Secretoras de Insulina/patologia , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/patologia , Metabolismo dos Lipídeos , Lipidômica/métodos , Fosfolipídeos/metabolismo , Ratos , Análise de Célula ÚnicaRESUMO
The natural peptide somatostatin has hormonal and cytostatic effects exerted by the binding to specific receptors in various tissues. Therapeutic uses are strongly prevented by its very short biological half-life of 1-2 min due to enzymatic hydrolysis, therefore encapsulation methodologies are explored to overcome the need for continuous infusion regimes. Multilamellar liposomes made of natural phosphatidylcholine were used for the incorporation of a mixture of somatostatin and sorbitol dissolved in citrate buffer at pH = 5. Lyophilization and reconstitution of the suspension were carried out, showing the flexibility of this preparation. Full characterization of this suspension was obtained as particle size, encapsulation efficiency and retarded release properties in aqueous medium and human plasma. Liposomal somatostatin incubated at 37 °C in the presence of Fe(II) and (III) salts were used as a biomimetic model of drug-cell membrane interaction, evidencing the free radical processes of peroxidation and isomerization that transform the unsaturated fatty acid moieties of the lipid vesicles. This study offers new insights into a liposomal delivery system and highlights molecular reactivity of sulfur-containing drugs with its carrier or biological membranes for pharmacological applications.
Assuntos
Lipossomos/química , Somatostatina/química , Somatostatina/farmacologia , Soluções Tampão , Cromatografia Líquida , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Radicais Livres/química , Humanos , Lipídeos/química , Espectrometria de Massas , Estrutura Molecular , Somatostatina/farmacocinéticaRESUMO
The reaction of hydroxyl radical (HOâ¢) with DNA produces many primary reactive species and many lesions as final products. In this study, we have examined the optical spectra of intermediate species derived from the reaction of HO⢠with a variety of single- and double-stranded oligodeoxynucleotides and ct-DNA in the range of 1 µs to 1 ms by pulse radiolysis using an Intensified Charged Coupled Device (ICCD) camera. Moreover, we applied our published analytical protocol based on an LC-MS/MS system with isotopomeric internal standards to enable accurate and precise measurements of purine lesion formation. In particular, the simultaneous measurement of the four purine 5',8-cyclo-2'-deoxynucleosides (cPu) and two 8-oxo-7,8-dihydro-2'-deoxypurine (8-oxo-Pu) was obtained upon reaction of genetic material with HO⢠radicals generated either by γ-radiolysis or Fenton-type reactions. Our results contributed to the debate in the literature regarding absolute level of lesions, method of HO⢠radical generation, 5'R/5'S diastereomeric ratio in cPu, and relative abundance between cPu and 8-oxo-Pu.
Assuntos
DNA/química , Radical Hidroxila/química , Oligodesoxirribonucleotídeos/química , Animais , Dano ao DNA/genética , Humanos , Peróxido de Hidrogênio/química , Ferro/química , Purinas/químicaRESUMO
Organisms store fatty acids in triacylglycerols in the form of lipid droplets, or hydrolyze triacylglycerols in response to energetic demands via activation of lipolytic or storage pathways. These pathways are complex sets of sequential reactions that are finely regulated in different cell types. Here we present a high spatial and temporal resolution-based method for the quantification of the turnover of fatty acids into triglycerides in live cells without introducing sample preparation artifacts. We performed confocal spectral imaging of intracellular micropolarity in cultured insulin secreting beta cells to detect micropolarity variations as they occur in time and at different pixels of microscope images. Acquired data are then analyzed in the framework of the spectral phasors technique. The method furnishes a metabolic parameter, which quantitatively assesses fatty acids - triacylglycerols turnover and the activation of lipolysis and storage pathways. Moreover, it provides a polarity profile, which represents the contribution of hyperpolar, polar and non-polar classes of lipids. These three different classes can be visualized on the image at a submicrometer resolution, revealing the spatial localization of lipids in cells under physiological and pathological settings. This new method allows for a fine-tuned, real-time visualization of the turnover of fatty acids into triglycerides in live cells with submicrometric resolution. It also detects imbalances between lipid storage and usage, which may lead to metabolic disorders within living cells and organisms.
Assuntos
Polaridade Celular , Microscopia Intravital/métodos , Lipídeos/análise , Lipólise , Células 3T3-L1 , Animais , Microscopia Intravital/instrumentação , Camundongos , Microscopia Confocal/instrumentação , Microscopia Confocal/métodos , Análise Espectral/instrumentação , Análise Espectral/métodosRESUMO
Docosahexaenoic acid (DHA) is a semiessential polyunsaturated fatty acid (PUFA) for eukaryotic cells that is found in natural sources such as fish and algal oils and widely used as an ingredient for omega-3 containing foods or supplements. DHA effects are connected to its natural structure with six cis double bonds, but geometrical monotrans isomers can be formed during distillation or deodorization processes, as an unwanted event that alters molecular characteristics and annihilates health benefits. The characterization of the six monotrans DHA regioisomers is an open issue to address for analytical, biological, and nutraceutical applications. Here we report the preparation, separation, and first identification of each isomer by a dual approach consisting of the following: (i) the direct thiyl radical-catalyzed isomerization of cis-DHA methyl ester and (ii) the two-step synthesis from cis-DHA methyl ester via monoepoxides as intermediates, which are separated and identified by nuclear magnetic resonance spectroscopy, followed by elimination for the unequivocal assignment of the double bond position. This monotrans DHA isomer library with NMR and GC analytical characterization was also used to examine the products of thiyl-radical-catalyzed isomerization of a fish oil sample and to evaluate the trans isomer content in omega-3 containing supplements commercially available in Italy and Spain.
Assuntos
Suplementos Nutricionais/análise , Ácidos Docosa-Hexaenoicos/análise , Óleos de Peixe/análise , Técnicas de Química Sintética , Ácidos Docosa-Hexaenoicos/síntese química , Compostos de Epóxi/síntese química , Isomerismo , Espectroscopia de Ressonância Magnética , Fotólise , Controle de QualidadeRESUMO
Cis lipids can be converted by thiols and free radicals into trans lipids, which are therefore a valuable tell-tale for free radical activity in the cell's lipidome. Our previous studies have shown that polyunsaturated lipids are isomerized by alkanethiyl radicals (Sâ¢) in a cycle propagated by reversible double-bond addition and terminated by radical H-abstraction from the lipid. A critical flaw in this picture has long been that the reported lipid abstraction rate from radiolysis studies is faster than addition-isomerization, implying that the "cycle" must be terminating faster than it is propagating! Herein, we resolved this longstanding puzzle by combining a detailed product analysis, with reinvestigation of the time-resolved kinetics, DFT calculations of the indicated pathways, and reformulation of the radical-stasis equations. We have determined thiol-coupled products in dilute solutions arise mainly from addition to the inside position of the bisallylic group, followed by rapid intramolecular H⢠transfer, yielding allylic radicals (LZZ + S⢠â SL⢠â SL'â¢) that are slowly reduced by thiol (SL'⢠+ SH â SL'H + Sâ¢). The first-order grow-in rate of the L-H⢠signal (kexp280nm) may therefore be dominated by the addition-H-translocation rather than slower direct Hâ¢-abstraction. Steady-state kinetic analysis of the new mechanism is consistent with products and the rates and trends for polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs), and mixtures, with and without physiological [O2]. Implications of this new paradigm for the thiol-ene reactivity fall in an interdisciplinary research area spanning from synthetic applications to metabolomics.
Assuntos
Ácidos Linoleicos/química , Compostos de Sulfidrila/química , Radicais Livres/química , Estrutura Molecular , Teoria QuânticaRESUMO
Apolipoprotein E (apoE) is a major lipid carrier of the lipoprotein transport system that plays critical roles in various pathologies. Human apoE has three common isoforms, the apoE4 being associated with Alzheimer's disease. This is the first study in the literature investigating the effects of apoE (apoE3 and apoE4 isoforms) on membrane fatty acid profile in neuroblastoma SK-N-SH cells. Fatty acid analyses were carried out by gas chromatography of the corresponding methyl esters (FAME). We observed the occurrence of membrane fatty acid remodeling in the presence of each of the two apoE isoforms. ApoE3 increased the membrane level of stearic acid and dihomo-gamma-linolenic acid (DGLA), whereas apoE4 had opposite effects. Both apoE3 and apoE4 increased saturated and monounsaturated fatty acids (SFA and MUFA), omega-6/omega-3 ratio and decreased total polyunsaturated fatty acid (PUFA) amount, but with various intensities. Moreover, both apoE isoforms decreased membrane homeostasis indexes such as PUFA balance, unsaturation index and peroxidation index. Our results highlight membrane property changes connected to the apoE isoforms suggesting membrane lipidomics to be inserted in further model studies of apolipoproteins in health and disease.
Assuntos
Apolipoproteína E4/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Ácidos Graxos/metabolismo , Membranas/metabolismo , Neuroblastoma/metabolismo , Ácido 8,11,14-Eicosatrienoico/metabolismo , Doença de Alzheimer/metabolismo , Apolipoproteína E3 , Linhagem Celular Tumoral , Homeostase/fisiologia , Humanos , Isoformas de Proteínas/metabolismo , Ácidos Esteáricos/metabolismoRESUMO
PURPOSE: A gluten-free diet (GFD) has been reported to negatively impact the quality of life (QoL) of coeliac disease (CD) patients. The gut-brain axis hormones ghrelin and leptin, with the brain-derived neurotrophic factor (BDNF), may affect QoL of CD patients undergoing GFD. Our aims were to evaluate whether: (a) the circulating concentrations of leptin, ghrelin and BDNF in CD patients were different from those in healthy subjects; (b) GFD might induce changes in their levels; (c) BDNF Val66Met polymorphism variability might affect BDNF levels; and (d) serum BDNF levels were related to dietary docosahexaenoic acid (DHA) as a neurotrophin modulator. METHODS: Nineteen adult coeliac patients and 21 healthy controls were included. A QoL questionnaire was administered, and serum concentrations of ghrelin, leptin, BDNF and red blood cell membrane DHA levels were determined at the enrolment and after 1 year of GFD. BDNF Val66Met polymorphism was analysed. RESULTS: Results from the questionnaire indicated a decline in QoL after GFD. Ghrelin and leptin levels were not significantly different between groups. BDNF levels were significantly (p = 0.0213) lower in patients after GFD (22.0 ± 2.4 ng/ml) compared to controls (31.2 ± 2.2 ng/ml) and patients at diagnosis (25.0 ± 2.5 ng/ml). BDNF levels correlated with DHA levels (p = 0.008, r = 0.341) and the questionnaire total score (p = 0.041, r = 0.334). CONCLUSIONS: Ghrelin and leptin seem to not be associated with changes in QoL of patients undergoing dietetic treatment. In contrast, a link between BDNF reduction and the vulnerability of CD patients to psychological distress could be proposed, with DHA representing a possible intermediate.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Doença Celíaca/dietoterapia , Doença Celíaca/genética , Dieta Livre de Glúten/efeitos adversos , Ácidos Docosa-Hexaenoicos/sangue , Polimorfismo de Nucleotídeo Único , Qualidade de Vida , Adulto , Alelos , Substituição de Aminoácidos , Fator Neurotrófico Derivado do Encéfalo/sangue , Estudos de Casos e Controles , Doença Celíaca/sangue , Doença Celíaca/fisiopatologia , Diarreia/etiologia , Diarreia/prevenção & controle , Dieta Livre de Glúten/psicologia , Membrana Eritrocítica/metabolismo , Feminino , Seguimentos , Frequência do Gene , Estudos de Associação Genética , Grelina/sangue , Heterozigoto , Humanos , Itália , Leptina/sangue , Masculino , Estudos Prospectivos , Estresse Psicológico/etiologiaRESUMO
The use of liposomes has been crucial for investigations in biomimetic chemical biology as a membrane model and in medicinal chemistry for drug delivery. Liposomes are made of phospholipids whose biophysical characteristics strongly depend on the type of fatty acid moiety, where natural unsaturated lipids always have the double bond geometry in the cis configuration. The influence of lipid double bond configuration had not been considered so far with respect to the competence of liposomes in delivery. We were interested in evaluating possible changes in the molecular properties induced by the conversion of the double bond from cis to trans geometry. Here we report on the effects of the addition of trans-phospholipids supplied in different amounts to other liposome constituents (cholesterol, neutral phospholipids and cationic surfactants), on the size, ζ-potential and stability of liposomal formulations and on their ability to encapsulate two dyes such as rhodamine B and fluorescein. From a biotechnological point of view, trans-containing liposomes proved to have different characteristics from those containing the cis analogues, and to influence the incorporation and release of the dyes. These results open new perspectives in the use of the unnatural lipid geometry, for the purpose of changing liposome behavior and/or of obtaining molecular interferences, also in view of synergic effects of cell toxicity, especially in antitumoral strategies.