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Sample records for active lipid oleamide

  1. In Vivo Evidence that N-Oleoylglycine Acts Independently of Its Conversion to Oleamide

    PubMed Central

    Chaturvedi, Shalini; Driscoll, William J.; Elliot, Brenda M.; Faraday, Martha M.; Grunberg, Neil E.; Mueller, Gregory P.

    2006-01-01

    Oleamide (cis-9-octadecenamide) is a member of an emerging class of lipid-signaling molecules, the primary fatty acid amides. A growing body of evidence indicates that oleamide mediates fundamental neurochemical processes including sleep, thermoregulation, and nociception. Nevertheless, the mechanism for oleamide biosynthesis remains unknown. The leading hypothesis holds that oleamide is synthesized from oleoylglycine via the actions of the peptide amidating enzyme, peptidylglycine alpha amidating monooxygenase (PAM). The present study investigated this hypothesis using pharmacologic treatments, physiologic assessments, and measurements of serum oleamide levels using a newly development enzyme-linked immunosorbant assay (ELISA). Oleamide and oleoylglycine both induced profound hypothermia and decreased locomotion, over equivalent dose ranges and time courses, whereas, closely related compounds, stearamide and oleic acid, were essentially without effect. While the biologic actions of oleamide and oleoylglycine were equivalent, the two compounds differed dramatically with respect to their effects on serum levels of oleamide. Oleamide administration (80 mg/kg) elevated blood-borne oleamide by eight-fold, whereas, the same dose of oleoylglycine had no effect on circulating oleamide levels. In addition, pretreatment with the established PAM inhibitor, disulfiram, produced modest reductions in the hypothermic responses to both oleoylglycine and oleamide, suggesting that the effects of disulfiram were not mediated through inhibition of PAM and a resulting decrease in the formation of oleamide from oleoylglycine. Collectively, these findings raise the possibilities that: (1) oleoylglycine possesses biologic activity that is independent of its conversion to oleamide, and (2) the increased availability of oleoylglycine as a potential substrate does not drive the biosynthesis of oleamide. PMID:17085322

  2. Enhanced radiosensitization of p53 mutant cells by oleamide

    SciTech Connect

    Lee, Yoon-Jin; Chung, Da Yeon; Lee, Su-Jae; Ja Jhon, Gil; Lee, Yun-Sil . E-mail: yslee@kcch.re.kr

    2006-04-01

    Purpose: Effect of oleamide, an endogenous fatty-acid primary amide, on tumor cells exposed to ionizing radiation (IR) has never before been explored. Methods and Materials: NCI H460, human lung cancer cells, and human astrocytoma cell lines, U87 and U251, were used. The cytotoxicity of oleamide alone or in combination with IR was determined by clonogenic survival assay, and induction of apoptosis was estimated by FACS analysis. Protein expressions were confirmed by Western blotting, and immunofluorescence analysis of Bax by use of confocal microscopy was also performed. The combined effect of IR and oleamide to suppress tumor growth was studied by use of xenografts in the thighs of nude mice. Results: Oleamide in combination with IR had a synergistic effect that decreased clonogenic survival of lung-carcinoma cell lines and also sensitized xenografts in nude mice. Enhanced induction of apoptosis of the cells by the combined treatment was mediated by loss of mitochondrial membrane potential, which resulted in the activation of caspase-8, caspase-9, and caspase-3 accompanied by cytochrome c release and Bid cleavage. The synergistic effects of the combined treatment were more enhanced in p53 mutant cells than in p53 wild-type cells. In p53 wild-type cells, both oleamide and radiation induced Bax translocation to mitochondria. On the other hand, in p53 mutant cells, radiation alone slightly induced Bax translocation to mitochondria, whereas oleamide induced a larger translocation. Conclusions: Oleamide may exhibit synergistic radiosensitization in p53 mutant cells through p53-independent Bax translocation to mitochondria.

  3. Antiallergic Activity of Ethanol Extracts of Arctium lappa L. Undried Roots and Its Active Compound, Oleamide, in Regulating FcεRI-Mediated and MAPK Signaling in RBL-2H3 Cells.

    PubMed

    Yang, Woong-Suk; Lee, Sung Ryul; Jeong, Yong Joon; Park, Dae Won; Cho, Young Mi; Joo, Hae Mi; Kim, Inhye; Seu, Young-Bae; Sohn, Eun-Hwa; Kang, Se Chan

    2016-05-11

    The antiallergic potential of Arctium lappa L. was investigated in Sprague-Dawley rats, ICR mice, and RBL-2H3 cells. Ethanol extract (90%) of A. lappa (ALE, 100 μg/mL) inhibited the degranulation rate by 52.9%, determined by the level of β-hexosaminidase. ALE suppressed passive cutaneous anaphylaxis (PCA) in rats and attenuated anaphylaxis and histamine release in mice. To identify the active compound of ALE, we subsequently fractionated and determined the level of β-hexosaminidase in all subfractions. Oleamide was identified as an active compound of ALE, which attenuated the secretion of histamine and the production of tumor necrosis factor (TNF)-α and interleukin-4 (IL-4) in cells treated with compound 48/80 or A23187/phorbol myristate acetate (PMA). Oleamide suppressed FcεRI-tyrosine kinase Lyn-mediated pathway, c-Jun N-terminal kinases (JNK/SAPK), and p38 mitogen-activated protein kinases (p38-MAPKs). These results showed that ALE and oleamide attenuated allergic reactions and should serve as a platform to search for compounds with antiallergic activity.

  4. Oleamide: a fatty acid amide signaling molecule in the cardiovascular system?

    PubMed

    Hiley, C Robin; Hoi, Pui Man

    2007-01-01

    Oleamide (cis-9,10-octadecenoamide), a fatty acid primary amide discovered in the cerebrospinal fluid of sleep-deprived cats, has a variety of actions that give it potential as a signaling molecule, although these actions have not been extensively investigated in the cardiovascular system. The synthetic pathway probably involves synthesis of oleoylglycine and then conversion to oleamide by peptidylglycine alpha-amidating monooxygenase (PAM); breakdown of oleamide is by fatty acid amide hydrolase (FAAH). Oleamide interacts with voltage-gated Na(+) channels and allosterically with GABA(A) and 5-HT(7) receptors as well as having cannabinoid-like actions. The latter have been suggested to be due to potentiation of the effects of endocannabinoids such as anandamide by inhibiting FAAH-mediated hydrolysis. This might underlie an "entourage effect" whereby co-released endogenous nonagonist congeners of endocannabinoids protect the active molecule from hydrolysis by FAAH. However, oleamide has direct agonist actions at CB(1) cannabinoid receptors and also activates the TRPV1 vanilloid receptor. Other actions include inhibition of gap-junctional communication, and this might give oleamide a role in myocardial development. Many of these actions are absent from the trans isomer of 9,10-octadecenoamide. One of the most potent actions of oleamide is vasodilation. In rat small mesenteric artery the response does not involve CB(1) cannabinoid receptors but another pertussis toxin-sensitive, G protein-coupled receptor, as yet unidentified. This receptor is sensitive to rimonabant and O-1918, an antagonist at the putative "abnormal-cannabidiol" or endothelial "anandamide" receptors. Vasodilation is mediated by endothelium-derived nitric oxide, endothelium-dependent hyperpolarization, and also through activation of TRPV1 receptors. A physiological role for oleamide in the heart and circulation has yet to be demonstrated, as has production by cells of the cardiovascular system, but

  5. Stereoselective modulatory actions of oleamide on GABAA receptors and voltage-gated Na+ channels in vitro: a putative endogenous ligand for depressant drug sites in CNS

    PubMed Central

    Verdon, Bernard; Zheng, Jian; Nicholson, Russell A; Ganelli, C Robin; Lees, George

    2000-01-01

    cis-9,10-octadecenoamide (‘oleamide') accumulates in CSF on sleep deprivation. It induces sleep in animals (the trans form is inactive) but its cellular actions are poorly characterized. We have used electrophysiology in cultures from embryonic rat cortex and biochemical studies in mouse nerve preparations to address these issues. Twenty μM cis-oleamide (but not trans) reversibly enhanced GABAA currents and depressed the frequency of spontaneous excitatory and inhibitory synaptic activity in cultured networks. cis-oleamide stereoselectively blocked veratridine-induced (but not K+-induced) depolarisation of mouse synaptoneurosomes (IC50, 13.9 μM). The cis isomer stereoselectively blocked veratridine-induced (but not K+-induced) [3H]-GABA release from mouse synaptosomes (IC50, 4.6 μM). At 20 μM cis-oleamide, but not trans, produced a marked inhibition of Na+ channel-dependent rises in intrasynaptosomal Ca2+. The physiological significance of these observations was examined by isolating Na+ spikes in cultured pyramidal neurones. Sixty-four μM cis-oleamide did not significantly alter the amplitude, rate of rise or duration of unitary action potentials (1 Hz). cis-Oleamide stereoselectively suppressed sustained repetitive firing (SRF) in these cells with an EC50 of 4.1 μM suggesting a frequency- or state-dependent block of voltage-gated Na+ channels. Oleamide is a stereoselective modulator of both postsynaptic GABAA receptors and presynaptic or somatic voltage-gated Na+ channels which are crucial for synaptic inhibition and conduction. The modulatory actions are strikingly similar to those displayed by sedative or anticonvulsant barbiturates and a variety of general anaesthetics. Oleamide may represent an endogenous modulator for drug receptors and an important regulator of arousal. PMID:10694234

  6. Differential proteomic analysis of the anti-depressive effects of oleamide in a rat chronic mild stress model of depression.

    PubMed

    Ge, Lin; Zhu, Ming-Ming; Yang, Jing-Yu; Wang, Fang; Zhang, Rong; Zhang, Jing-Hai; Shen, Jing; Tian, Hui-Fang; Wu, Chun-Fu

    2015-04-01

    Depression is a complex psychiatric disorder, and its etiology and pathophysiology are not completely understood. Depression involves changes in many biogenic amine, neuropeptide, and oxidative systems, as well as alterations in neuroendocrine function and immune-inflammatory pathways. Oleamide is a fatty amide which exhibits pharmacological effects leading to hypnosis, sedation, and anti-anxiety effects. In the present study, the chronic mild stress (CMS) model was used to investigate the antidepressant-like activity of oleamide. Rats were exposed to 10weeks of CMS or control conditions and were then subsequently treated with 2weeks of daily oleamide (5mg/kg, i.p.), fluoxetine (10mg/kg, i.p.), or vehicle. Protein extracts from the hippocampus were then collected, and hippocampal maps were generated by way of two-dimensional gel electrophoresis (2-DE). Altered proteins induced by CMS and oleamide were identified through mass spectrometry and database searches. Compared to the control group, the CMS rats exhibited significantly less body weight gain and decreased sucrose consumption. Treatment with oleamide caused a reversal of the CMS-induced deficit in sucrose consumption. In the proteomic analysis, 12 protein spots were selected and identified. CMS increased the levels of adenylate kinase isoenzyme 1 (AK1), nucleoside diphosphate kinase B (NDKB), histidine triad nucleotide-binding protein 1 (HINT1), acyl-protein thioesterase 2 (APT-2), and glutathione S-transferase A4 (GSTA4). Compared to the CMS samples, seven spots changed significantly following treatment with oleamide, including GSTA4, glutathione S-transferase A6 (GSTA6), GTP-binding nuclear protein Ran (Ran-GTP), ATP synthase subunit d, transgelin-3, small ubiquitin-related modifier 2 (SUMO2), and eukaryotic translation initiation factor 5A-1 (eIF5A1). Of these seven proteins, the level of eIF5A1 was up-regulated, whereas the remaining proteins were down-regulated. In conclusion, oleamide has antidepressant

  7. Efficiency Enhancement of Inverted Structure Perovskite Solar Cells via Oleamide Doping of PCBM Electron Transport Layer.

    PubMed

    Xia, Fei; Wu, Qiliang; Zhou, Pengcheng; Li, Yi; Chen, Xiang; Liu, Qing; Zhu, Jun; Dai, Songyuan; Lu, Yalin; Yang, Shangfeng

    2015-06-24

    An amphiphilic surfactant, oleamide, was applied to dope the PCBM electron transport layer (ETL) of inverted structure perovskite solar cells (ISPSCs), resulting in a dramatic efficiency enhancement. Under the optimized oleamide doping ratio of 5.0 wt %, the power conversion efficiency of the CH3NH3PbIxCl(3-x) perovskite-based ISPSC device is enhanced from 10.05% to 12.69%, and this is primarily due to the increases of both fill factor and short-circuit current. According to the surface morphology study of the perovskite/PCBM bilayer film, oleamide doping improves the coverage of PCBM ETL onto the perovskite layer, and this is beneficial for the interfacial contact between the perovskite layer and the Ag cathode and consequently the electron transport from perovskite to the Ag cathode. Such an improved electron transport induced by oleamide doping is further evidenced by the impedance spectroscopic study, revealing the prohibited electron-hole recombination at the interface between the perovskite layer and the Ag cathode.

  8. Lipid Dependent Mechanisms of Protein Pump Activity

    DTIC Science & Technology

    1989-05-23

    properties which result form the colligative interactions of many lipid molecules. Important materials properties include . . . i I I II II I i I 1 the...d identify by olock number) *This project is aime at investigating if a lipid elastic property , known as the spontaneous radius of curvature Ro’, is...a regulated membrane property and if its value modulates membrane protein activity. Specific aims reported on here include: 1) Correlation of ion pump

  9. Results from in vitro and ex vivo skin aging models assessing the antiglycation and anti-elastase MMP-12 potential of glycylglycine oleamide

    PubMed Central

    Bogdanowicz, Patrick; Haure, Marie-José; Ceruti, Isabelle; Bessou-Touya, Sandrine; Castex-Rizzi, Nathalie

    2016-01-01

    Background Glycation is an aging reaction of naturally occurring sugars with dermal proteins. Type I collagen and elastin are most affected by glycation during intrinsic chronological aging. Aim To study the in vitro and ex vivo assays in human skin cells and explants and the antiaging effects of glycylglycine oleamide (GGO). Materials and methods The antiglycation effect of GGO was assessed in a noncellular in vitro study on collagen and, ex vivo, by immunohistochemical staining on human skin explants (elastin network glycation). The ability of GGO to contract fibroblasts was assessed in a functional assay, and its anti-elastase (MMP-12) activity was compared to that of oleic acid alone, glycylglycine (GG) alone, and oleic acid associated with GG. Results In vitro, GGO reduced the glycation of type I collagen. Ex vivo, GGO restored the expression of fibrillin-1 inhibited by glycation. Furthermore, GGO induced a tissue retraction of almost 30%. Moreover, the MMP-12 activity was inhibited by up to 60%. Conclusion Under the present in vitro and ex vivo conditions, GGO prevents glycation of the major structural proteins of the dermis, helping to reduce the risk of rigidification. By maintaining the elastic function of the skin, GGO may be a promising sparring partner for other topical antiaging agents. PMID:27382322

  10. Lipid Dependent Mechanisms of Protein Pump Activity

    DTIC Science & Technology

    1993-04-29

    AD -A26 4 48~_ _ _ _ _ __ _ _ _ _ _ _ IDF C~ tl~,’ ApiZ’ C, tdfii 1111iII~iji .. rirTATION PAGE OWNo0MB ý8 2a SECURITY CLASSiFICAT ON. A 3 0SR37...between lipid composition and the spontaneous curva - ture of native membranes. The first two specific objectives were successfully met, while the...1992). Basically, the results show that the spontaneous curva - tures of lipids extracted from mycoplasma membranes cluster tightly, even under growth

  11. Obesity and lipid stress inhibit carnitine acetyltransferase activity[S

    PubMed Central

    Seiler, Sarah E.; Martin, Ola J.; Noland, Robert C.; Slentz, Dorothy H.; DeBalsi, Karen L.; Ilkayeva, Olga R.; An, Jie; Newgard, Christopher B.; Koves, Timothy R.; Muoio, Deborah M.

    2014-01-01

    Carnitine acetyltransferase (CrAT) is a mitochondrial matrix enzyme that catalyzes the interconversion of acetyl-CoA and acetylcarnitine. Emerging evidence suggests that this enzyme functions as a positive regulator of total body glucose tolerance and muscle activity of pyruvate dehydrogenase (PDH), a mitochondrial enzyme complex that promotes glucose oxidation and is feedback inhibited by acetyl-CoA. Here, we used tandem mass spectrometry-based metabolic profiling to identify a negative relationship between CrAT activity and muscle content of lipid intermediates. CrAT specific activity was diminished in muscles from obese and diabetic rodents despite increased protein abundance. This reduction in enzyme activity was accompanied by muscle accumulation of long-chain acylcarnitines (LCACs) and acyl-CoAs and a decline in the acetylcarnitine/acetyl-CoA ratio. In vitro assays demonstrated that palmitoyl-CoA acts as a direct mixed-model inhibitor of CrAT. Similarly, in primary human myocytes grown in culture, nutritional and genetic manipulations that promoted mitochondrial influx of fatty acids resulted in accumulation of LCACs but a pronounced decrease of CrAT-derived short-chain acylcarnitines. These results suggest that lipid-induced antagonism of CrAT might contribute to decreased PDH activity and glucose disposal in the context of obesity and diabetes. PMID:24395925

  12. Steady-state compartmentalization of lipid membranes by active proteins.

    PubMed Central

    Sabra, M C; Mouritsen, O G

    1998-01-01

    Using a simple microscopic model of lipid-protein interactions, based on the hydrophobic matching principle, we study some generic aspects of lipid-membrane compartmentalization controlled by a dispersion of active integral membrane proteins. The activity of the proteins is simulated by conformational excitations governed by an external drive, and the deexcitation is controlled by interaction of the protein with its lipid surroundings. In response to the flux of energy into the proteins from the environment and the subsequent dissipation of energy into the lipid bilayer, the lipid-protein assembly reorganizes into a steady-state structure with a typical length scale determined by the strength of the external drive. In the specific case of a mixed dimyristoylphosphatidylcholine-distearoylphosphatidylcholine bilayer in the gel-fluid coexistence region, it is shown explicitly by computer simulation that the activity of an integral membrane protein can lead to a compartmentalization of the lipid-bilayer membrane. The compartmentalization is related to the dynamical process of phase separation and lipid domain formation. PMID:9533687

  13. Hydrophobic Moiety of Cationic Lipids Strongly Modulates Their Transfection Activity

    SciTech Connect

    Koynova, Rumiana; Tenchov, Boris; Wang, Li; MacDonald, Robert C.

    2010-01-18

    Synthetic cationic lipids are widely used components of nonviral gene carriers, and the factors regulating their transfection efficiency are the subject of considerable interest. In view of the important role that electrostatic interactions with the polyanionic nucleic acids play in formation of lipoplexes, a common empirical approach to improving transfection has been the synthesis and testing of amphiphiles with new versions of positively charged polar groups, while much less attention has been given to the role of the hydrophobic lipid moieties. On the basis of data for {approx}20 cationic phosphatidylcholine (PC) derivatives, here we demonstrate that hydrocarbon chain variations of these lipids modulate by over 2 orders of magnitude their transfection efficiency. The observed molecular structure-activity relationship manifests in well-expressed dependences of activity on two important molecular characteristics, chain unsaturation and total number of carbon atoms in the lipid chains, which is representative of the lipid hydrophobic volume and hydrophilic-lipophilic ratio. Transfection increases with decrease of chain length and increase of chain unsaturation. Maximum transfection was found for cationic PCs with monounsaturated 14:1 chains. It is of particular importance that the high-transfection lipids strongly promote cubic phase formation in zwitterionic membrane phosphatidylethanolamine (PE). These remarkable correlations point to an alternative, chain-dependent process in transfection, not related to the electrostatic cationic-anionic lipid interactions.

  14. A new dermocosmetic containing retinaldehyde, delta-tocopherol glucoside and glycylglycine oleamide for managing naturally aged skin: results from in vitro to clinical studies

    PubMed Central

    Rouvrais, Céline; Bacqueville, Daniel; Bogdanowicz, Patrick; Haure, Marie-José; Duprat, Laure; Coutanceau, Christine; Castex-Rizzi, Nathalie; Duplan, Hélène; Mengeaud, Valérie; Bessou-Touya, Sandrine

    2017-01-01

    Introduction Natural aging of skin tissues, the addition of the cumulative action of the time and radiation exposure result in skin atrophy, wrinkles and degeneration of the extracellular matrix (ECM). The aim of the study was to investigate the beneficial effect of a combination containing retinaldehyde (RAL), delta-tocopherol glucoside (delta-TC) and glycylglycine ole-amide (GGO) and of a dermocosmetic containing the combination. Materials and methods The protective effect of the combination was assessed through in vitro gene expression of ultraviolet (UV)-irradiated fibroblasts. A skin aging assay using UV light on ex vivo skin samples and a clinical study conducted in 36 women aged from 35 to 55 years with a minimum of level 4 to a maximum of level 6 on the crow’s feet photoscale assessed the antiaging effect of the dermocosmetic. Results When added to UV-irradiated fibroblasts, the combination substantially improved the ECM in activating the elastin fiber production (fibrillin 2, fibulin 1 and 5 and lysyl oxidase-like 2) as well as that of proteins involved in the cellular ECM interactions (integrin b1, paxillin and actin a2). An ex vivo photodamaged human skin model showed that the dermocosmetic formulation containing the combination of the active ingredients protected the elastic network against UV-induced alterations including both elastin and fibrillin-rich fibers in the dermis. A daily application of the dermocosmetic for 2 months on naturally aged skin resulted in a statistically significant improvement (p<0.05) of visible signs of aging comprising crow’s feet, wrinkles and periocular fine lines. Finally, the formulation was well tolerated. Conclusion The dermocosmetic containing RAL, delta-TC and GGO provides a substantial benefit in the daily care of naturally aged skin in women aged 35–55 years. PMID:28203099

  15. Immunobiological activities of synthetic lipid A analogs with low endotoxicity.

    PubMed Central

    Kotani, S; Takada, H; Takahashi, I; Ogawa, T; Tsujimoto, M; Shimauchi, H; Ikeda, T; Okamura, H; Tamura, T; Harada, K

    1986-01-01

    Synthetic lipid A analogs, beta(1-6)glucosamine disaccharide 1,4'-bisphosphates, which possesses four tetradecanoyl groups at the 2- and 2'-amino, and 3- and 3'-hydroxyl groups (LA-17-PP), and each two of the (R)-3-hydroxytetradecanoyl and tetradecanoyl groups at the 2- and 2'-amino and 3- and 3'-hydroxyl groups, respectively (LA-18-PP), were far less endotoxic than synthetic (506, LA-15-PP) and bacterial Escherichia coli type lipid A's; neither compound showed any detectable lethal toxicity in chicken embryos or preparatory activity for the local Shwartzman reaction in rabbits. Also both compounds were only weakly pyrogenic and comparably less lethally toxic in galactosamine-loaded mice than the reference synthetic and bacterial lipid A's and a synthetic counterpart to biosynthetic lipid A precursor Ia (406, LA-14-PP). Nevertheless, LA-17-PP and LA-18-PP exhibited definite in vivo immunoadjuvant activity in mice, and the ability to induce a possible tumor necrosis factor and alpha/beta interferon in Mycobacterium bovis BCG and Propionibacterium acnes-primed mice, respectively, although these activities were weaker than those of the reference lipid A's. 4'-Monophosphate analogs of the above two test compounds exhibited neither endotoxic nor beneficial activities, but they showed remarkable in vitro bioactivities comparable to those of the corresponding bisphosphate compounds; the ability to activate the human complement system and the clotting enzyme cascade of horseshoe crab amoebocyte lysate, stimulatory effects on guinea pig and murine peritoneal macrophages, and murine splenocytes. PMID:3781622

  16. Structure-activity relationship in cationic lipid mediated gene transfection.

    PubMed

    Niculescu-Duvaz, Dan; Heyes, James; Springer, Caroline J

    2003-07-01

    Non-viral synthetic vectors for gene delivery represent a safer alternative to viral vectors. Their main drawback is the low transfection efficiency, especially in vivo. Among the non-viral vectors currently in use, the cationic liposomes composed of cationic lipids are the most common. This review discusses the physicochemical properties of cationic lipids, the formation, macrostructure and specific parameters of the corresponding formulated liposomes, and the effect of all these parameters on transfection efficiency. The optimisation of liposomal vectors requires both the understanding of the biological variables involved in the transfection process, and the effect of the structural elements of the cationic lipids on these biological variables. The biological barriers relevant for in vitro and in vivo transfection are identified, and solutions to overcome them based on rational design of the cationic lipids are discussed. The review focuses on the relationship between the structure of the cationic lipid and the transfection activity. The structure is analysed in a modular manner. The hydrophobic domain, the cationic head group, the backbone that acts as a scaffold for the other domains, the linkers between backbone, hydrophobic domain and cationic head group, the polyethyleneglycol chains and the targeting moiety are identified as distinct elements of the cationic lipids used in gene therapy. The main chemical functionalities used to built these domains, as well as overall molecular features such as architecture and geometry, are presented. Studies of structure-activity relationships of each cationic lipid domain, including the authors', and the trends identified by these studies, help furthering the understanding of the mechanism governing the formation and behaviour of cationic liposomes in gene delivery, and therefore the rational design of new improved cationic lipids vectors capable of achieving clinical significance.

  17. How Membrane-Active Peptides Get into Lipid Membranes.

    PubMed

    Sani, Marc-Antoine; Separovic, Frances

    2016-06-21

    The structure-function relationship for a family of antimicrobial peptides (AMPs) from the skin of Australian tree frogs is discussed and compared with that of peptide toxins from bee and Australian scorpion venoms. Although these membrane-active peptides induce a similar cellular fate by disrupting the lipid bilayer integrity, their lytic activity is achieved via different modes of action, which are investigated in relation to amino acid sequence, secondary structure, and membrane lipid composition. In order to better understand what structural features govern the interaction between peptides and lipid membranes, cell-penetrating peptides (CPPs), which translocate through the membrane without compromising its integrity, are also discussed. AMPs possess membrane lytic activities that are naturally designed to target the cellular membrane of pathogens or competitors. They are extremely diverse in amino acid composition and often show specificity against a particular strain of microbe. Since our antibiotic arsenal is declining precariously in the face of the rise in multiantibiotic resistance, AMPs increasingly are seen as a promising alternative. In an effort to understand their molecular mechanism, biophysical studies of a myriad of AMPs have been reported, yet no unifying mechanism has emerged, rendering difficult the rational design of drug leads. Similarly, a wide variety of cytotoxic peptides are found in venoms, the best known being melittin, yet again, predicting their activity based on a particular amino acid composition or secondary structure remains elusive. A common feature of these membrane-active peptides is their preference for the lipid environment. Indeed, they are mainly unstructured in solution and, in the presence of lipid membranes, quickly adsorb onto the surface, change their secondary structure, eventually insert into the hydrophobic core of the membrane bilayer, and finally disrupt the bilayer integrity. These steps define the molecular

  18. Comparative phytohormone profiles, lipid kinase and lipid phosphatase activities in barley aleurone, coleoptile, and root tissues.

    PubMed

    Meringer, Maria V; Villasuso, Ana L; Pasquaré, Susana J; Giusto, Norma M; Machado, Estela E; Racagni, Graciela E

    2012-09-01

    We analyzed lipid kinase and lipid phosphatase activities and determined endogenous phytohormone levels by liquid chromatography-tandem mass spectrometry in root and coleoptile tissues following germination of barley (Hordeum vulgare) seeds. The enzymes showing highest activity in aleurone cells were diacylglycerol kinase (DAG-k, EC 2.7.1.107) and phosphatidate kinase (PA-k). The ratio of gibberellins (GAs) to abscisic acid (ABA) was 2-fold higher in aleurone than in coleoptile or root tissues. In coleoptiles, phosphatidylinositol 4-kinase (PI4-k, EC 2.7.1.67) showed the highest enzyme activity, and jasmonic acid (JA) level was higher than in aleurone. In roots, activities of PI4-k, DAG-k, and PA-k were similar, and salicylic acid (SA) showed the highest concentration. In the assays to evaluate the hydrolysis of DGPP (diacylglycerol pyrophosphate) and PA (phosphatidic acid) we observed that PA hydrolysis by LPPs (lipid phosphate phosphatases) was not modified; however, the diacylglycerol pyrophosphate phosphatase (DGPPase) was strikingly higher in coleoptile and root tissues than to aleurone. Relevance of these findings in terms of signaling responses and seedling growth is discussed.

  19. Cytoskeletal Modulation of Lipid Interactions Regulates Lck Kinase Activity*

    PubMed Central

    Chichili, Gurunadh R.; Cail, Robert C.; Rodgers, William

    2012-01-01

    The actin cytoskeleton promotes clustering of proteins associated with cholesterol-dependent rafts, but its effect on lipid interactions that form and maintain rafts is not understood. We addressed this question by determining the effect of disrupting the cytoskeleton on co-clustering of dihexadecyl-(C16)-anchored DiO and DiI, which co-enrich in ordered lipid environments such as rafts. Co-clustering was assayed by fluorescence resonance energy transfer (FRET) in labeled T cells, where rafts function in the phosphoregulation of the Src family kinase Lck. Our results show that probe co-clustering was sensitive to depolymerization of actin filaments with latrunculin B (Lat B), inhibition of myosin II with blebbistatin, and treatment with neomycin to sequester phosphatidylinositol 4,5-bisphosphate. Cytoskeletal effects on lipid interactions were not restricted to order-preferring label because co-clustering of C16-anchored DiO with didodecyl (C12)-anchored DiI, which favors disordered lipids, was also reduced by Lat B and blebbistatin. Furthermore, conditions that disrupted probe co-clustering resulted in activation of Lck. These data show that the cytoskeleton globally modulates lipid interactions in the plasma membrane, and this property maintains rafts that function in Lck regulation. PMID:22613726

  20. The influence of membrane lipid structure on plasma membrane Ca2+ -ATPase activity.

    PubMed

    Tang, Daxin; Dean, William L; Borchman, Douglas; Paterson, Christopher A

    2006-03-01

    Lipid composition and Ca(2+)-ATPase activity both change with age and disease in many tissues. We explored relationships between lipid composition/structure and plasma membrane Ca(2+)-ATPase (PMCA) activity. PMCA was purified from human erythrocytes and was reconstituted into liposomes prepared from human ocular lens membrane lipids and synthetic lipids. Lens lipids were used in this study as a model for naturally ordered lipids, but the influence of lens lipids on PMCA function is especially relevant to the lens since calcium homeostasis is vital to lens clarity. Compared to fiber cell lipids, epithelial lipids exhibited an ordered to disordered phase transition temperature that was 12 degrees C lower. Reconstitution of PMCA into lipids was essential for maximal activity. PMCA activity was two to three times higher when the surrounding phosphatidylcholine molecules contained acyl chains that were ordered (stiff) compared to disordered (fluid) acyl chains. In a completely ordered lipid hydrocarbon chain environment, PMCA associates more strongly with the acidic lipid phosphatidylserine in comparison to phosphatidylcholine. PMCA associates much more strongly with phosphatidylcholine containing disordered hydrocarbon chains than ordered hydrocarbon chains. PMCA activity is influenced by membrane lipid composition and structure. The naturally high degree of lipid order in plasma membranes such as those found in the human lens may serve to support PMCA activity. The absence of PMCA activity in the cortical region of human lenses is apparently not due to a different lipid environment. Changes in lipid composition such as those observed with age or disease could potentially influence PMCA function.

  1. Cancer Cells Differentially Activate and Thrive on De Novo Lipid Synthesis Pathways in a Low-Lipid Environment

    PubMed Central

    Daniëls, Veerle W.; Smans, Karine; Royaux, Ines; Chypre, Melanie

    2014-01-01

    Increased lipogenesis is a hallmark of a wide variety of cancers and is under intense investigation as potential antineoplastic target. Although brisk lipogenesis is observed in the presence of exogenous lipids, evidence is mounting that these lipids may adversely affect the efficacy of inhibitors of lipogenic pathways. Therefore, to fully exploit the therapeutic potential of lipid synthesis inhibitors, a better understanding of the interrelationship between de novo lipid synthesis and exogenous lipids and their respective role in cancer cell proliferation and therapeutic response to lipogenesis inhibitors is of critical importance. Here, we show that the proliferation of various cancer cell lines (PC3M, HepG2, HOP62 and T24) is attenuated when cultured in lipid-reduced conditions in a cell line-dependent manner, with PC3M being the least affected. Interestingly, all cell lines - lipogenic (PC3M, HepG2, HOP62) as well as non-lipogenic (T24) - raised their lipogenic activity in these conditions, albeit to a different degree. Cells that attained the highest lipogenic activity under these conditions were best able to cope with lipid reduction in term of proliferative capacity. Supplementation of the medium with very low density lipoproteins, free fatty acids and cholesterol reversed this activation, indicating that the mere lack of lipids is sufficient to activate de novo lipogenesis in cancer cells. Consequently, cancer cells grown in lipid-reduced conditions became more dependent on de novo lipid synthesis pathways and were more sensitive to inhibitors of lipogenic pathways, like Soraphen A and Simvastatin. Collectively, these data indicate that limitation of access to exogenous lipids, as may occur in intact tumors, activates de novo lipogenesis is cancer cells, helps them to thrive under these conditions and makes them more vulnerable to lipogenesis inhibitors. These observations have important implications for the design of new antineoplastic strategies targeting

  2. Effect of acylethanolamides on lipid peroxidation and paraoxonase activity.

    PubMed

    Zolese, Giovanna; Bacchetti, Tiziana; Masciangelo, Simona; Ragni, Letizia; Ambrosi, Simona; Ambrosini, Annarina; Marini, Milvia; Ferretti, Gianna

    2008-01-01

    N-acylethanolamides (NAEs) are hydrophobic molecules synthesized in many tissues. An increase in the plasma levels of NAEs has been observed in human diseases. Previous studies have suggested that NAEs could exert a protective effect against oxidative stress. Aim of the study was to investigate whether NAEs (oleoylethanolamide, palmitoylethanolamide and anandamide), differing for acyl chain length and unsaturation, exert a protective role against plasma lipid peroxidation triggered by incubation with Cu2+2 or AAPH (2,2'-azobis(2-amidinopropane) dihydrochloride). Moreover, we investigated the effect of NAEs on the activity of HDL-associated paraoxonase (PON1), an enzyme involved in the antioxidant end anti-inflammatory role of human high density lipoproteins (HDL). The results demonstrated that the NAEs protect plasma lipids and PON1 activity against AAPH and/or copper-induced oxidation.

  3. P-glycoprotein ATPase activity requires lipids to activate a switch at the first transmission interface.

    PubMed

    Loo, Tip W; Clarke, David M

    2016-04-01

    P-glycoprotein (P-gp) is an ABC (ATP-Binding Cassette) drug pump. A common feature of ABC proteins is that they are organized into two wings. Each wing contains a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Drug substrates and ATP bind at the interface between the TMDs and NBDs, respectively. Drug transport involves ATP-dependent conformational changes between inward- (open, NBDs far apart) and outward-facing (closed, NBDs close together) conformations. P-gps crystallized in the presence of detergent show an open structure. Human P-gp is inactive in detergent but basal ATPase activity is restored upon addition of lipids. The lipids might cause closure of the wings to bring the NBDs close together to allow ATP hydrolysis. We show however, that cross-linking the wings together did not activate ATPase activity when lipids were absent suggesting that lipids may induce other structural changes required for ATPase activity. We then tested the effect of lipids on disulfide cross-linking of mutants at the first transmission interface between intracellular loop 4 (TMD2) and NBD1. Mutants L443C/S909C and L443C/R905C but not G471C/S909C and V472C/S909C were cross-linked with oxidant when in membranes. The mutants were then purified and cross-linked with or without lipids. Mutants G471C/S909C and V472C/S909C cross-linked only in the absence of lipids whereas mutants L443C/S909C and L443C/R905C were cross-linked only in the presence of lipids. The results suggest that lipids activate a switch at the first transmission interface and that the structure of P-gp is different in detergents and lipids.

  4. Novel Cationic Lipids with Enhanced Gene Delivery and Antimicrobial Activity

    PubMed Central

    Fein, David E.; Bucki, Robert; Byfield, Fitzroy; Leszczynska, Katarzyna; Janmey, Paul A.

    2010-01-01

    Cationic lipids facilitate plasmid delivery, and some cationic sterol-based compounds have antimicrobial activity because of their amphiphilic character. These dual functions are relevant in the context of local ongoing infection during intrapulmonary gene transfer for cystic fibrosis. The transfection activities of two cationic lipids, dexamethasone spermine (DS) and disubstituted spermine (D2S), were tested as individual components and mixtures in bovine aortic endothelial cells and A549 cells. The results showed a 3- to 7-fold improvement in transgene expression for mixtures of DS with 20 to 40 mol% D2S. D2S and coformulations with DS, dioleoyl phosphatidylethanolamine, and DNA exhibited potent bactericidal activity against Escherichia coli MG1655, Bacillus subtilis, and Pseudomonas aeruginosa PAO1, which was maintained in bronchoalveolar lavage fluid. Complete bacterial killing was demonstrated at ∼5 μM, including gene delivery formulations, with 2 orders of magnitude higher tolerance before eukaryotic membrane disruption (erythrocyte hemolysis). D2S also exhibited lipopolysaccharide (LPS) scavenging activity resulting in significant inhibition of LPS-mediated activation of human neutrophils with 85 and 65% lower interleukin-8 released at 12 and 24 h, respectively. Mixtures of DS and D2S can improve transfection activity over common lipofection reagents, and D2S has strong antimicrobial action suited for the suppression of bacterial-mediated inflammation. PMID:20573781

  5. Differential anti-lipid peroxidative activity of melatonin

    NASA Astrophysics Data System (ADS)

    Kawanishi, Shinya; Sakurai, Hiromu

    2002-01-01

    Scavenging activities of melatonin, which is a pineal secretory product and functions in circadian biology, and its related compounds against reactive oxygen species such as superoxide anion radical, hydrogen peroxide, hydroxyl radical and singlet oxygen as well as organic peroxide radical (t-BuOO•) were evaluated chemically by using electron spin resonance-spin trap and chemiluminescence methods. Antioxidative activity of the compounds was estimated by IC50 value (µM), 50% inhibiting concentration of a compound against reactive oxygen species formed in each system, and the second-order rate constants ( k 2) for the reactions of the compounds and superoxide anion radical or hydroxyl radical. Because melatonin has exhibited the highest scavenging activity against t-BuOO•, the biochemical anti-lipid peroxide radical scavenging activities of melatonin were examined. We found that melatonin exhibits higher anti-lipid peroxidative activity in the rat brain microsomes than in the rat liver microsomal and liposomal systems, suggesting that melatonin may function as a treatment for reactive oxygen species-related diseases of the brain.

  6. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity[S

    PubMed Central

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-01-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids. PMID:26175473

  7. Evidences for anti-mycobacterium activities of lipids and surfactants.

    PubMed

    Hussain, Afzal; Singh, Sandeep Kumar

    2016-01-01

    Tuberculosis is the most widespread and deadly airborne disease caused by Mycobacterium tuberculosis. The two-pronged lethal effect on the bacteria using lipids/surfactants and anti-tubercular drugs may render the miniaturization of dose owing to synergistic and tandem effect of both. The current research has been focused on screening and evaluating various lipids/surfactants possessing inherent anti-mycobacterium activity that can ferry the anti-tubercular drugs. In vitro anti-mycobacterium activity was evaluated using agar well diffusion method. Furthermore, time-concentration dependent killing and DNA/RNA content release studies were performed to correlate the findings. The exact mechanism of bacterial killing was further elucidated by electron/atomic force microscopy studies. Finally, to negate any toxicity, in vitro hemolysis and toxicity studies were performed. The study revealed that capmul MCM C-8, labrasol and acconon C-80 possessed highest in vitro anti-mycobacterium activity. Electron/atomic force microscopy results confirmed in vitro studies and verified the killing of Mycobacterium owing to the release of cytoplasmic content after cell wall fragmentation and disruption. Moreover, the least hemolysis and hundred percent survivals rate of mice using the excipients demonstrated the safety aspects of explored excipients that can ferry the anti-tubercular drugs. The present study concluded the safe, efficient and synergistic activity of the explored excipients and anti-tubercular drugs in controlling the menace of tuberculosis.

  8. Physical activity-induced alterations on tissue lipid composition and lipid metabolism in fattening pigs.

    PubMed

    Daza, A; Rey, A I; Olivares, A; Cordero, G; Toldrá, F; López-Bote, C J

    2009-04-01

    In a first experiment one group of pigs was maintained in free-range conditions according to the traditional way in a Mediterranean forest (exercised-1) and another group was housed individually and received acorns (sedentary-1). In a second experiment two groups of pigs were fed a mixed diet for the whole experimental period. One of these groups was housed individually in 8m(2) pens (sedentary-2). The other group was housed in a corridor and forced to walk daily (exercised-2). The subcutaneous fat and neutral lipids of muscle from the exercised pigs fed acorns had higher C18:1n-9, MUFA, C18:1/C18:0, MUFA/SAT and lower C16:0 and SAT when compared with the fat from the pigs fed acorns in confinement. Those exercised animals fed the mixed diet had also lower C16:0 and SAT in subcutaneous fat and lower SAT and higher C18:2, C18:3, PUFA and MUFA/SAT in neutral lipids when compared with the sedentary pigs, which may indicate that delta-9-desaturase activity was higher in exercised than in sedentary pigs. Exercised pigs had higher acid and neutral esterases and lower neutral lipase activity than sedentary pigs. No differences in the α-tocopherol concentration and TBARS values of meat samples among the pigs that received a mixed diet either exercised or sedentary were observed. The moderate exercise reduced the postprandrial concentrations of triglycerides in plasma, but did not reduce other plasma levels.

  9. Highly antioxidant carotene-lipid nanocarriers: synthesis and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Lacatusu, Ioana; Badea, Nicoleta; Ovidiu, Oprea; Bojin, Dionezie; Meghea, Aurelia

    2012-06-01

    The objective of this study was to explore the potential of two natural oils (squalene—Sq and grape seed oil—GSO) to prepare biocompatible antioxidant nanostructured lipid carriers—NLCs as a safety and protective formulation for sensitive β-carotene. For this purpose different oil-in-water nanoemulsions stabilized by a combination of alkylpolyoxy ethylene sorbitans, lecithin and a block copolymer, were prepared using a melt high-shear homogenization process. The physico-chemical characteristics of the carotene-loaded NLCs were firstly investigated in detail. The smaller lipid nanoparticles have been obtained by using Tween 20 as main non-ionic surfactant, with average diameters of about 85 nm for GSO and 89 nm for Sq, with a polydispersity index <0.19. The developed carotene-NLCs presented an excellent physical stability with almost all zeta potential values ranging between -29 ÷ -40 mV. The differential scanning calorimetry analysis showed that the β-carotene incorporation has led to a perturbation of solid lipid matrix with a less ordered arrangement. By UV-Vis spectroscopy it was evidenced that after encapsulation β-carotene adopts a supramolecular structure demonstrated by appearance of a shoulder at 530 nm related to a β-carotene triplet-triplet absorption. The carotene-NLCs have been also evaluated in terms of in vitro antioxidant properties. The presence of Sq and GSO produced a significant effect on the antioxidant capacity of developed NLCs. The samples prepared with GSO and Tween 80 as main surfactant showed the highest antioxidant activity (AA %) against free oxygen radicals, exhibiting an enhancement of 35 % for loaded NLCs, as comparing to pure carotene. In addition to these properties, the ability of NLCs to manifest antibacterial activity was tested against Escherichia coli bacteria. The antibacterial analysis shown that loaded-NLCs develop an effective inhibition zone against bacteria growth and it was dependent in a higher extent on the

  10. The antagonist activity of lipid IVa on the stimulation by lipid A of TNF-alpha production from canine blood mononuclear cells.

    PubMed

    Takasawa, Kenji; Kano, Rui; Maruyama, Haruhiko; Hasegawa, Atsuhiko; Kamata, Hiroshi

    2011-09-15

    Lipid A, the active component of lipopolysaccharide (LPS), exists in the outer membrane of Gram-negative bacteria and binds to the Toll-like receptor 4 (TLR4) and MD-2 complex. On the other hand, the synthetic precursor of Escherichia coli lipid A, tetraacylated lipid IVa, is an agonist for TLR4 and MD-2 complex in murine, equine and feline cells but is an antagonist for lipid A in human cells. The aim of the study was to examine the function of canine Toll-like receptor 4 (TLR4) and MD-2 complex on canine blood mononuclear cells (BMC), by analyzing lipid A- or lipid IVa-induction of TNF-α production from these cells in order to understand canine innate immune system. After 5-h culture of canine BMC with lipid A (lipid A culture) or lipid IVa (lipid IVa culture), the TNF-α, as determined by ELISA, had increased in the supernatants of the lipid A cultures in a dose-dependent manner, whereas the TNF-α was undetectable in supernatant of lipid IVa-treated cultures. The TNF-α was statistically significantly different between the lipid A and lipid IVa cultures (100 and 1000 ng/ml). TNF-α production from canine BMC was inhibited, in a lipid IVa-dose-dependent manner, when the BMC were pre-cultured with lipid IVa for 60 min and then cultured with lipid A for 5h, while in control BMC cultures production if TNF-α was unchanged. These results indicate that the TNF-α production stimulated by lipid A was competed out by pre-exposing the BMC to lipid IVa. Thus, lipid A is an agonist for TNF-α production in canine BMC, whereas lipid IVa appears to be an antagonist against this lipid A stimulation of canine BMC.

  11. Improved antimycobacterial activity of rifampin using solid lipid nanoparticles

    NASA Astrophysics Data System (ADS)

    Aboutaleb, Ehsan; Noori, Massoumeh; Gandomi, Narges; Atyabi, Fatemeh; Fazeli, Mohammad Reza; Jamalifar, Hossein; Dinarvand, Rassoul

    2012-10-01

    Rifampin (RIF) is one of the front-line drugs in therapy of tuberculosis (TB). The emergence of multidrug-resistant strains of mycobacteria has greatly contributed to the increased incidence of TB. Nano-based formulation of several antimicrobials has been shown to improve either antibacterial efficacy or pharmacokinetic behavior. In this study, RIF-loaded solid lipid nanoparticles (SLNs) were prepared by a modified microemulsion-based method and their particle size, zeta potential, encapsulation efficiency, morphology, and antibacterial activity against Mycobacterium fortuitum were evaluated. The resulting SLNs were spherical with diameter of about 100 nm, with low negative zeta potential, and an encapsulation efficiency of 82%. The formulation also sustained the drug release for 72 h. The antimycobacterial efficacy was greatly improved against M. fortuitum, and the minimum inhibitory concentration of drug-loaded SLNs was eight times less than free RIF. Drug-free SLNs and the ingredients showed no antibacterial effect. It can be concluded that as expected, solid lipid nanoparticles are promising vehicles for enhanced antimycobacterial effect of rifampin.

  12. Thermal activation of superheated lipid-coated perfluorocarbon drops.

    PubMed

    Mountford, Paul A; Thomas, Alec N; Borden, Mark A

    2015-04-28

    This study explored the thermal conditions necessary for the vaporization of superheated perfluorocarbon nanodrops. Droplets C3F8 and C4F10 coated with a homologous series of saturated diacylphosphatidylcholines were formed by condensation of 4 μm diameter microbubbles. These drops were stable at room temperature and atmospheric pressure, but they vaporized back into microbubbles at higher temperatures. The vaporization transition was measured as a function of temperature by laser light extinction. We found that C3F8 and C4F10 drops experienced 90% vaporization at 40 and 75 °C, respectively, near the theoretical superheat limits (80-90% of the critical temperature). We therefore conclude that the metastabilty of these phase-change agents arises not from the droplet Laplace pressure altering the boiling point, as previously reported, but from the metastability of the pure superheated fluid to homogeneous nucleation. The rate of C4F10 drop vaporization was quantified at temperatures ranging from 55 to 75 °C, and an apparent activation energy barrier was calculated from an Arrhenius plot. Interestingly, the activation energy increased linearly with acyl chain length from C14 to C20, indicating that lipid interchain cohesion plays an important role in suppressing the vaporization rate. The vaporized drops (microbubbles) were found to be unstable to dissolution at high temperatures, particularly for C14 and C16. However, proper choice of the fluorocarbon and lipid species provided a nanoemulsion that could undergo at least ten reversible condensation/vaporization cycles. The vaporization properties presented in this study may facilitate the engineering of tunable phase-shift particles for diagnostic imaging, targeted drug delivery, tissue ablation, and other applications.

  13. Effects of Oxidized Tallow on the Rabbit Serum Lipids and Antioxidant Activity of the In-vitro Lipids

    PubMed Central

    Zeb, Alam; Rahman, Waheed ur

    2012-01-01

    This paper describes the effects of thermally oxidized tallow on the serum lipids profile and radical scavenging activity (RSA) of the lipids extracted from the different tissues of the rabbits. Tallow was thermally oxidized at 130℃ for 9, 18, 27, 36 and 45 h respectively. Thermally oxidized tallow was fed to the local strain of Himalayan rabbits for one week. Results show that oxidation increases the formation of hydroperoxides and decrease the level of radical scavenging activity of the tallow. The rabbit serum lipids profile showed a dose dependent increase in triglyceride, total cholesterol and LDL-cholesterol. However, no statistically significant increase was observed in the HDL-cholesterol with an increase of oxidation time. Serum glucose and rabbits body weight decrease significantly (p < 0.05) and was highly correlated with the serum lipids profile. The percent RSA of the lipids extracted from the liver, brain and muscles tissues showed a significant decrease with respect to 0.5, 1.0 and 1.5 g/body weight as well as oxidation time. Data suggests that thermal oxidation and use of thermally oxidized beef tallow is harmful and therefore an alternative way of cooking should be used. PMID:24278604

  14. Effects of Oxidized Tallow on the Rabbit Serum Lipids and Antioxidant Activity of the In-vitro Lipids.

    PubMed

    Zeb, Alam; Rahman, Waheed Ur

    2012-09-01

    This paper describes the effects of thermally oxidized tallow on the serum lipids profile and radical scavenging activity (RSA) of the lipids extracted from the different tissues of the rabbits. Tallow was thermally oxidized at 130℃ for 9, 18, 27, 36 and 45 h respectively. Thermally oxidized tallow was fed to the local strain of Himalayan rabbits for one week. Results show that oxidation increases the formation of hydroperoxides and decrease the level of radical scavenging activity of the tallow. The rabbit serum lipids profile showed a dose dependent increase in triglyceride, total cholesterol and LDL-cholesterol. However, no statistically significant increase was observed in the HDL-cholesterol with an increase of oxidation time. Serum glucose and rabbits body weight decrease significantly (p < 0.05) and was highly correlated with the serum lipids profile. The percent RSA of the lipids extracted from the liver, brain and muscles tissues showed a significant decrease with respect to 0.5, 1.0 and 1.5 g/body weight as well as oxidation time. Data suggests that thermal oxidation and use of thermally oxidized beef tallow is harmful and therefore an alternative way of cooking should be used.

  15. Mechanical properties that influence antimicrobial peptide activity in lipid membranes.

    PubMed

    Marín-Medina, Nathaly; Ramírez, Diego Alejandro; Trier, Steve; Leidy, Chad

    2016-12-01

    Antimicrobial peptides are small amphiphilic proteins found in animals and plants as essential components of the innate immune system and whose function is to control bacterial infectious activity. In order to accomplish their function, antimicrobial peptides use different mechanisms of action which have been deeply studied in view of their potential exploitation to treat antibiotic-resistant bacterial infections. One of the main mechanisms of action of these peptides is the disruption of the bacterial membrane through pore formation, which, in some cases, takes place via a monomer to oligomer cooperative transition. Previous studies have shown that lipid composition, and the presence of exogenous components, such as cholesterol in model membranes or carotenoids in bacteria, can affect the potency of distinct antimicrobial peptides. At the same time, considering the membrane as a two-dimensional material, it has been shown that membrane composition defines its mechanical properties which might be relevant in many membrane-related processes. Nevertheless, the correlation between the mechanical properties of the membrane and antimicrobial peptide potency has not been considered according to the importance it deserves. The relevance of these mechanical properties in membrane deformation due to peptide insertion is reviewed here for different types of pores in order to elucidate if indeed membrane composition affects antimicrobial peptide activity by modulation of the mechanical properties of the membrane. This would also provide a better understanding of the mechanisms used by bacteria to overcome antimicrobial peptide activity.

  16. High-throughput fluorescence-activated cell sorting for lipid hyperaccumulating Chlamydomonas reinhardtii mutants.

    PubMed

    Xie, Bo; Stessman, Dan; Hart, Jason H; Dong, Haili; Wang, Yingjun; Wright, David A; Nikolau, Basil J; Spalding, Martin H; Halverson, Larry J

    2014-09-01

    The genetically tractable microalga Chlamydomonas reinhardtii has many advantages as a model for renewable bioproducts and/or biofuels production. However, one limitation of C. reinhardtii is its relatively low-lipid content compared with some other algal species. To overcome this limitation, we combined ethane methyl sulfonate mutagenesis with fluorescence-activated cell sorting (FACS) of cells stained with the lipophilic stain Nile Red to isolate lipid hyperaccumulating mutants of C. reinhardtii. By manipulating the FACS gates, we sorted mutagenized cells with extremely high Nile Red fluorescence signals that were rarely detected in nonmutagenized populations. This strategy successfully isolated several putative lipid hyperaccumulating mutants exhibiting 23% to 58% (dry weight basis) higher fatty acid contents than their progenitor strains. Significantly, for most mutants, nitrogen starvation was not required to attain high-lipid content nor was there a requirement for a deficiency in starch accumulation. Microscopy of Nile Red stained cells revealed that some mutants exhibit an increase in the number of lipid bodies, which correlated with TLC analysis of triacyglycerol content. Increased lipid content could also arise through increased biomass production. Collectively, our findings highlight the ability to enhance intracellular lipid accumulation in algae using random mutagenesis in conjunction with a robust FACS and lipid yield verification regime. Our lipid hyperaccumulating mutants could serve as a genetic resource for stacking additional desirable traits to further increase lipid production and for identifying genes contributing to lipid hyperaccumulation, without lengthy lipid-induction periods.

  17. Effect of Low Dose Gamma Irradiation together with Lipid A on Human Leukocytes Activities In Vitro

    NASA Astrophysics Data System (ADS)

    Belyakova, E.; Dubnickova, M.; Boreyko, A.

    2010-01-01

    The influence of gamma irradiation and of Lipid A from Escherichia coli on phagocytosis, lyzosyme and peroxidase activities of human leukocytes, in vitro was investigated. Leukocytes samples were irradiated with 1 and 5 Gy, respectively. The number of irradiated leukocytes was decreased in the irradiated samples. Only samples with additive Lipid A were not damaged by irradiation. The Lipid A had positive influence on biological activities of the irradiated leukocytes.

  18. Isoleukotrienes are biologically active free radical products of lipid peroxidation.

    PubMed

    Harrison, K A; Murphy, R C

    1995-07-21

    The free radical oxidation of arachidonic acid esterified to glycerophospholipids is known to generate complex metabolites, termed isoprostanes, that share structural features of prostaglandins derived from prostaglandin H2 synthase. Furthermore, certain isoprostanes have been found to exert biological activity through endogenous receptors on cell surfaces. Using mass spectrometry and ancillary techniques, the free radical oxidation of 1-hexadecanoyl-2-arachidonoyl-glycerophosphocholine was studied in the search for products of arachidonic acid isomeric to the leukotrienes that are derived from 5-lipoxygenase-catalyzed metabolism of arachidonic acid. Several conjugated triene metabolites were chromatographically separated from known 5-lipoxygenase products and structures characterized as 5,12-dihydroxy-6,8,10,14-eicosatetraenoic acid esterified to the glycerophosphocholine backbone. We have termed these products as B4-isoleukotrienes. Following saponification some, but not all, B4-isoleukotrienes were found to exert biological activity in elevating intracellular calcium in Indo-1-loaded human polymorphonuclear leukocytes. This activity could be blocked by a leukotriene B4 receptor antagonist. An EC50 of approximately 30 nM was determined for one unique B4-isoleukotriene with a relative retention index of 2.54. We have shown that free radical processes can lead to the formation of biologically active isoleukotrienes in glycerophosphocholine liposomes, and we propose that B4-isoleukotrienes may also be formed in membrane glycerophospholipids as a result of lipid peroxidation during tissue injury. Such B4-isoleukotrienes could then mediate events of tissue damage through activation of leukotriene B4 receptors on target cells.

  19. The effect of charged lipids on bacteriorhodopsin membrane reconstitution and its photochemical activities

    SciTech Connect

    Wang Zhen; Bai Jing; Xu Yuhong

    2008-07-11

    Bacteriorhodopsin (BR) was reconstituted into artificial lipid membrane containing various charged lipid compositions. The proton pumping activity of BR under flash and continuous illumination, proton permeability across membrane, as well as the decay kinetics of the photocycle intermediate M{sub 412} were studied. The results showed that lipid charges would significantly affect the orientation of BR inserted into lipid membranes. In liposomes containing anionic lipids, BRs were more likely to take natural orientation as in living cells. In neutral or positively charged liposomes, most BRs were reversely assembled, assuming an inside out orientation. Moreover, the lipids charges also affect BR's M intermediate kinetics, especially the slow component in M intermediate decay. The half-life M{sub 412s} increased significantly in BRs in liposomes containing cationic lipids, while decreased in those in anionic liposomes.

  20. [Biological activity of lipids and photosynthetic pigments of Sargassum pallidum C. Agardh].

    PubMed

    Gerasimenko, N I; Martyias, E A; Logvinov, S V; Busarova, N G

    2014-01-01

    The biological activity of lipids and photosynthetic pigments of the kelp Sargassum pallidum (Turner) C. Agardh has been studied. Free fatty acids and their esters demonstrated considerable antimicrobial activity against bacteria (Staphylococcus aureus[ital] and Escherichia coli), yeast-like fungi (Candida albicans), and opportunistic pathogenic (Aspergilius niger) and phytopathogenic (Fusarium oxysporum, and Septoria glycines) fungi. Glyceroglycolipids and neutral lipids demonstrated moderate activity. Fucoxanthin and chlorophylls weakly suppressed the growth of microorganisms. None of the studied substances demonstrated activity against Ehrlich's carcinoma. It was shown that the season of weed harvesting affected both antimicrobial and hemolytic activities of different lipids due to changes in their fatty acid composition.

  1. HAMLET - A protein-lipid complex with broad tumoricidal activity.

    PubMed

    Ho, James C S; Nadeem, Aftab; Svanborg, Catharina

    2017-01-15

    HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is a tumoricidal protein-lipid complex with broad effects against cancer cells of different origin. The therapeutic potential is emphasized by a high degree of specificity for tumor tissue. Here we review early studies of HAMLET, in collaboration with the Orrenius laboratory, and some key features of the subsequent development of the HAMLET project. The early studies focused on the apoptotic response that accompanies death in HAMLET treated tumor cells and the role of mitochondria in this process. In subsequent studies, we have identified a sequence of interactions that starts with the membrane integration of HAMLET and the activation of ion fluxes followed by HAMLET internalization, progressive inhibition of MAPK kinases and GTPases and sorting of HAMLET to different cellular compartments, including the nuclei. Therapeutic efficacy of HAMLET has been demonstrated in animal models of glioblastoma, bladder cancer and intestinal cancer. In clinical studies, HAMLET has been shown to target skin papillomas and bladder cancers. The findings identify HAMLET as a new drug candidate with promising selectivity for cancer cells and a strong therapeutic potential.

  2. Activity of a novel-designed antimicrobial peptide and its interaction with lipids.

    PubMed

    Yu, Lanlan; Fan, Qiannan; Yue, Xiu; Mao, Yexuan; Qu, Lingbo

    2015-04-01

    A new antimicrobial peptide l-RW containing double amphipathic binding sequences was designed, and its biological activities were investigated in the present study. L-RW showed antibacterial activity against several bacterial strains but low cytotoxicity to mammalian cells and low hemolytic activity to red blood cells, which makes it a potential and promising peptide for further development. Microscale thermophoresis (MST), a new technique, was applied to study the antimicrobial peptide-lipid interaction for the first time, which examined the binding affinities of this new antimicrobial peptide to various lipids, including different phospholipids, mixture lipids and bacterial lipid extracts. The results demonstrated that l-RW bound preferentially to negatively charged lipids over neutral lipids, which was consistent with the biological activities, revealing the important role of electrostatic interaction in the binding process. L-RW also showed higher binding affinity for lipid extract from Staphyloccocus aureus compared with Pseudomonas aeruginosa and Escherichia coli, which were in good agreement with the higher antibacterial activity against S. aureus than P. aeruginosa and E. coli, suggesting that the binding affinity is capable to predict the antibacterial activity to some extent. Additionally, the binding of l-RW to phospholipids was also performed in fetal bovine serum solution by MST, which revealed that the components in biological solution may have interference with the binding event. The results proved that MST is a useful and potent tool in antimicrobial peptide-lipid interaction investigation.

  3. Enhanced detection of lipid transfer inhibitor protein activity by an assay involving only low density lipoprotein.

    PubMed

    Morton, R E; Greene, D J

    1994-11-01

    Lipid transfer inhibitor protein (LTIP) activity has been typically quantitated by its ability to suppress lipid transfer protein-mediated lipid movement between low density lipoprotein (LDL) and high density lipoprotein (HDL). In an attempt to establish an LTIP activity assay that is more sensitive, we have exploited the reported preference of the inhibitor protein to interact with LDL. A lipid transfer assay was established that involves LDL as both the donor and the acceptor; LDL in one of these two pools was biotinylated to facilitate its removal with immobilized avidin. Compared to the standard LDL to HDL assay, LTIP inhibited lipid transfer from radiolabeled LDL to biotin-LDL 7-fold more. In the absence of LTIP, lipid transfer activity was the same in both assays. An added benefit of this assay was the near linearity (up to 85%) of the inhibitory response, in contrast to the highly curvilinear response of LTIP in LDL to HDL transfer assays. The high sensitivity of the LDL to biotin-LDL transfer assay in measuring LTIP activity could not be duplicated by other transfer assays including assays containing only HDL (HDL to biotin-HDL), assays between liposomes and LDL, or assays between LDL and HDL where the concentration of lipoproteins was reduced 10-fold. Thus, LTIP activity is most effectively measured in homologous lipid transfer assays involving only LDL (and its biotin derivative). This increased sensitivity to LTIP suggests that the inhibitor binds more avidly to the LDL surface than does lipid transfer protein.

  4. Lipid lowering and imaging protease activation in atherosclerosis Lipid therapy and MMP imaging in atherosclerosis

    PubMed Central

    Challa, Azariyas; Zhang, Jiasheng; Golestani, Reza; Jung, Jae-Joon; Robinson, Simon; Sadeghi, Mehran M.

    2014-01-01

    Background Lipid lowering is a mainstay of modern therapeutic approach to atherosclerosis. We sought to evaluate matrix metalloproteinase (MMP)-targeted microSPECT imaging for tracking of the effect of lipid-lowering interventions on plaque biology in atherosclerotic mice in vivo. Methods and Results ApoE−/− mice fed on a high fat diet (HFD) for 2 months were randomly assigned to continuation of HFD, HFD plus simvastatin, HFD plus fenofibrate and high fat withdrawal (HFW). The animals underwent serial microSPECT/CT imaging using RP805, a 99mTc-labeled MMP-targeted tracer at 1 and 4 weeks after randomization. All three interventions reduced total blood cholesterol by 4 weeks. In animals on HFD, aortic arch RP805 uptake significantly increased from 1 week to 4 weeks. Tracer uptake in fenofibrate and HFW groups was significantly lower than uptake in the HFD group at 4 weeks. Similarly, CD 68 gene expression, reflecting plaque inflammation, was significantly lower in fenofibrate and HFW groups compared to HFD group. MMP tracer uptake significantly correlated with aortic CD68, but not VE-cadherin or smooth muscle α-actin expression. Conclusions MMP tracer uptake paralleled the effect of lipid-lowering interventions on plaque inflammation in atherosclerotic mice. MMP-targeted imaging may be used to track the effect of therapeutic interventions in atherosclerosis. PMID:24368425

  5. How Lipid Membranes Affect Pore Forming Toxin Activity.

    PubMed

    Rojko, Nejc; Anderluh, Gregor

    2015-12-15

    Pore forming toxins (PFTs) evolved to permeate the plasma membrane of target cells. This is achieved in a multistep mechanism that usually involves binding of soluble protein monomer to the lipid membrane, oligomerization at the plane of the membrane, and insertion of part of the polypeptide chain across the lipid membrane to form a conductive channel. Introduced pores allow uncontrolled transport of solutes across the membrane, inflicting damage to the target cell. PFTs are usually studied from the perspective of structure-function relationships, often neglecting the important role of the bulk membrane properties on the PFT mechanism of action. In this Account, we discuss how membrane lateral heterogeneity, thickness, and fluidity influence the pore forming process of PFTs. In general, lipid molecules are more accessible for binding in fluid membranes due to steric reasons. When PFT specifically binds ordered domains, it usually recognizes a specific lipid distribution pattern, like sphingomyelin (SM) clusters or SM/cholesterol complexes, and not individual lipid species. Lipid domains were also suggested to act as an additional concentration platform facilitating PFT oligomerization, but this is yet to be shown. The last stage in PFT action is the insertion of the transmembrane segment across the membranes to build the transmembrane pore walls. Conformational changes are a spontaneous process, and sufficient free energy has to be available for efficient membrane penetration. Therefore, fluid bilayers are permeabilized more readily in comparison to highly ordered and thicker liquid ordered lipid phase (Lo). Energetically more costly insertion into the Lo phase can be driven by the hydrophobic mismatch between the thinner liquid disordered phase (Ld) and large protein complexes, which are unable to tilt like single transmembrane segments. In the case of proteolipid pores, membrane properties can directly modulate pore size, stability, and even selectivity. Finally

  6. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity.

    PubMed

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-09-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids.

  7. Structure-activity investigation on the gene transfection properties of cardiolipin mimicking gemini lipid analogues.

    PubMed

    Bajaj, Avinash; Paul, Bishwajit; Kondaiah, Paturu; Bhattacharya, Santanu

    2008-06-01

    A structure-activity relationship has been explored on the gene transfection efficiencies of cardiolipin mimicking gemini lipid analogues upon variation of length and hydrophilicity of the spacer between the cationic ammonium headgroups and lipid hydrocarbon chain lengths. All the gemini lipids were found to be highly superior in gene transfer abilities as compared to their monomeric lipid and a related commercially available formulation. Pseudoglyceryl gemini lipids bearing an oxyethylene (-CH2-(CH2-O-CH2)m-CH2-) spacer were found to be superior gene transfecting agents as compared to those bearing polymethylene (-CH2)m-) spacers. The major characteristic feature of the present set of gemini lipids is their serum compatibility, which is most often the major hurdle in liposome-mediated gene delivery.

  8. Enhanced Lipid and Biodiesel Production from Glucose-Fed Activated Sludge: Kinetics an Microbial Community Analysis

    EPA Science Inventory

    An innovative approach to increase biofuel feedstock lipid yields from municipal sewage sludge via manipulation of carbon:nitrogen (C:N) ratio and glucose loading in activated sludge bioreactors was investigated. Sludge lipid and fatty acid methyl ester (biodiesel) yields (% cel...

  9. Charge requirements of lipid II flippase activity in Escherichia coli.

    PubMed

    Butler, Emily K; Tan, Wee Boon; Joseph, Hildy; Ruiz, Natividad

    2014-12-01

    Peptidoglycan (PG) is an extracytoplasmic glycopeptide matrix essential for the integrity of the envelope of most bacteria. The PG building block is a disaccharide-pentapeptide that is synthesized as a lipid-linked precursor called lipid II. The translocation of the amphipathic lipid II across the cytoplasmic membrane is required for subsequent incorporation of the disaccharide-pentapeptide into PG. In Escherichia coli, the essential inner membrane protein MurJ is the lipid II flippase. Previous studies showed that 8 charged residues in the central cavity region of MurJ are crucial for function. Here, we completed the functional analysis of all 57 charged residues in MurJ and demonstrated that the respective positive or negative charge of the 8 aforementioned residues is required for proper MurJ function. Loss of the negative charge in one of these residues, D39, causes a severe defect in MurJ biogenesis; by engineering an intragenic suppressor mutation that restores MurJ biogenesis, we found that this charge is also essential for MurJ function. Because of the low level of homology between MurJ and putative orthologs from Gram-positive bacteria, we explored the conservation of these 8 charged residues in YtgP, a homolog from Streptococcus pyogenes. We found that only 3 positive charges are similarly positioned and essential in YtgP; YtgP possesses additional charged residues within its predicted cavity that are essential for function and conserved among Gram-positive bacteria. From these data, we hypothesize that some charged residues in the cavity region of MurJ homologs are required for interaction with lipid II and/or energy coupling during transport.

  10. Identification of hydrophobic amino acids required for lipid activation of C. elegans CTP:phosphocholine cytidylyltransferase

    PubMed Central

    Braker, Jay D; Hodel, Kevin J.; Mullins, David R.; Friesen, Jon A.

    2009-01-01

    CTP:phosphocholine cytidylyltransferase (CCT), critical for phosphatidylcholine biosynthesis, is activated by translocation to the membrane surface. The lipid activation region of Caenorhabditis elegans CCT is between residues 246 and 266 of the 347 amino acid polypeptide, a region proposed to form an amphipathic alpha helix. When leucine 246, tryptophan 249, isoleucine 256, isoleucine 257, or phenylalanine 260, on the hydrophobic face of the helix, were changed individually to serine low activity was observed in the absence of lipid vesicles, similar to wild-type CCT, while lipid stimulated activity was reduced compared to wild-type CCT. Mutational analysis of phenylalanine 260 implicated this residue as a contributor to auto-inhibition of CCT while mutation of L246, W249, I256, and I257 simultaneously to serine resulted in significantly higher activity in the absence of lipid vesicles and an enzyme that was not lipid activated. These results support a concerted mechanism of lipid activation that requires multiple residues on the hydrophobic face of the putative amphipathic alpha helix. PMID:19836342

  11. Lipid II-based antimicrobial activity of the lantibiotic plantaricin C.

    PubMed

    Wiedemann, Imke; Böttiger, Tim; Bonelli, Raquel Regina; Schneider, Tanja; Sahl, Hans-Georg; Martínez, Beatriz

    2006-04-01

    We analyzed the mode of action of the lantibiotic plantaricin C (PlnC), produced by Lactobacillus plantarum LL441. Compared to the well-characterized type A lantibiotic nisin and type B lantibiotic mersacidin, which are both able to interact with the cell wall precursor lipid II, PlnC displays structural features of both prototypes. In this regard, we found that lipid II plays a key role in the antimicrobial activity of PlnC besides that of pore formation. The pore forming activity of PlnC in whole cells was prevented by shielding lipid II on the cell surface. However, in contrast to nisin, PlnC was not able to permeabilize Lactococcus lactis cells or to form pores in 1,2-dioleoyl-sn-glycero-3-phosphocholine liposomes supplemented with 0.1 mol% purified lipid II. This emphasized the different requirements of these lantibiotics for pore formation. Using cell wall synthesis assays, we identified PlnC as a potent inhibitor of (i) lipid II synthesis and (ii) the FemX reaction, i.e., the addition of the first Gly to the pentapeptide side chain of lipid II. As revealed by thin-layer chromatography, both reactions were clearly blocked by the formation of a PlnC-lipid I and/or PlnC-lipid II complex. On the basis of the in vivo and in vitro activities of PlnC shown in this study and the structural lipid II binding motifs described for other lantibiotics, the specific interaction of PlnC with lipid II is discussed.

  12. [Effect of phensuccinal on lipid metabolism, lipid peroxidation, and antioxidant system activity in rabbits with dithiazone-induced diabetes].

    PubMed

    Gorbenko, N I; Poltorak, V V; Gladkikh, A I; Ivanova, O V

    2003-01-01

    A three-month administration of phensuccinal improved glucose homeostasis, decreased the levels of total cholesterol, triglycerides, fatty acids, and low-density lipoproteins in the blood serum, and reduced the lipid peroxidation rate as compared to the untreated diabetic control. In addition, phensuccinal increased the content of the antiatherogenic high-density lipoprotein fraction and the related paraoxonase enzyme activity. The preventive effect of phensuccinal with respect to diabetic dyslipidemia development, together with the antioxidant action, show this compound to be a promising therapeutic means of preventing and/or reducing macrovascular complications in diabetic patients.

  13. Determinants of the tumor suppressor INPP4B protein and lipid phosphatase activities.

    PubMed

    Lopez, Sandra M; Hodgson, Myles C; Packianathan, Charles; Bingol-Ozakpinar, Ozlem; Uras, Fikriye; Rosen, Barry P; Agoulnik, Irina U

    2013-10-18

    The tumor suppressor INPP4B is an important regulator of phosphatidyl-inositol signaling in the cell. Reduced INPP4B expression is associated with poor outcomes for breast, prostate, and ovarian cancer patients. INPP4B contains a CX5R catalytic motif characteristic of dual-specificity phosphatases, such as PTEN. Lipid phosphatase activity of INPP4B has previously been described. In this report we show that INPP4B can dephosphorylate para-nitrophenyl phosphate (pNPP) and 6,8-difluoro-4-methylumbelliferyl (DiFMUP), synthetic phosphotyrosine analogs, suggesting that INPP4B has protein tyrosine phosphatase (PTP) activity. Using mutagenesis, we examined the functional role of specific amino acids within the INPP4B C842KSAKDR catalytic site. The K843M mutant displayed increased pNPP hydrolysis, the K846M mutant lost lipid phosphatase activity with no effect on PTP activity, and the D847E substitution ablated PTP activity and significantly reduced lipid phosphatase activity. Further, we show that INPP4B but not PTEN is able to reduce tyrosine phosphorylation of Akt1 and both the lipid and PTP activity of INPP4B likely contribute to the reduction of Akt1 phosphorylation. Taken together our data identified key residues in the INPP4B catalytic domain associated with lipid and protein phosphatase activities and found a robust downstream target regulated by INPP4B but not PTEN.

  14. A Two-Stage Model for Lipid Modulation of the Activity of Integral Membrane Proteins

    PubMed Central

    Dodes Traian, Martín M.; Cattoni, Diego I.; Levi, Valeria; González Flecha, F. Luis

    2012-01-01

    Lipid-protein interactions play an essential role in the regulation of biological function of integral membrane proteins; however, the underlying molecular mechanisms are not fully understood. Here we explore the modulation by phospholipids of the enzymatic activity of the plasma membrane calcium pump reconstituted in detergent-phospholipid mixed micelles of variable composition. The presence of increasing quantities of phospholipids in the micelles produced a cooperative increase in the ATPase activity of the enzyme. This activation effect was reversible and depended on the phospholipid/detergent ratio and not on the total lipid concentration. Enzyme activation was accompanied by a small structural change at the transmembrane domain reported by 1-aniline-8-naphtalenesulfonate fluorescence. In addition, the composition of the amphipilic environment sensed by the protein was evaluated by measuring the relative affinity of the assayed phospholipid for the transmembrane surface of the protein. The obtained results allow us to postulate a two-stage mechanistic model explaining the modulation of protein activity based on the exchange among non-structural amphiphiles at the hydrophobic transmembrane surface, and a lipid-induced conformational change. The model allowed to obtain a cooperativity coefficient reporting on the efficiency of the transduction step between lipid adsorption and catalytic site activation. This model can be easily applied to other phospholipid/detergent mixtures as well to other membrane proteins. The systematic quantitative evaluation of these systems could contribute to gain insight into the structure-activity relationships between proteins and lipids in biological membranes. PMID:22723977

  15. Isolation and characterization of a complement-activating lipid extracted from human atherosclerotic lesions

    PubMed Central

    1990-01-01

    The major characteristics of human atherosclerotic lesions are similar to those of a chronic inflammatory reaction, namely fibrosis, mesenchymal cell proliferation, the presence of resident macrophages, and cell necrosis. Atherosclerosis exhibits in addition the feature of lipid (mainly cholesterol) accumulation. The results of the present report demonstrate that a specific cholesterol-containing lipid particle present in human atherosclerotic lesions activates the complement system to completion. Thus, lipid could represent a stimulatory factor for the inflammatory reaction, whose underlying mechanistic basis may be, at least in part, complement activation. The complement-activating lipid was purified from saline extracts of aortic atherosclerotic lesions by sucrose density gradient centrifugation followed by molecular sieve chromatography on Sepharose 2B. It contained little protein other than albumin, was 100-500 nm in size, exhibited an unesterified to total cholesterol ratio of 0.58 and an unesterified cholesterol to phospholipid ratio of 1.2. The lipid, termed lesion lipid complement (LCA), activated the alternative pathway of complement in a dose-dependent manner. Lesion-extracted low density lipoprotein (LDL) obtained during the purification procedure failed to activate complement. Specific generation of C3a desArg and C5b-9 by LCA indicated C3/C5 convertase formation with activation proceeding to completion. Biochemical and electron microscopic evaluations revealed that much of the C5b-9 present in atherosclerotic lesions is membraneous, rather than fluid phase SC5b-9. The observations reported herein establish a link between lipid insudation and inflammation in atherosclerotic lesions via the mechanism of complement activation. PMID:2373993

  16. The shedding activity of ADAM17 is sequestered in lipid rafts

    SciTech Connect

    Tellier, Edwige; Canault, Matthias; Rebsomen, Laure; Bonardo, Bernadette; Juhan-Vague, Irene; Nalbone, Gilles; Peiretti, Franck . E-mail: Franck.Peiretti@medecine.univ-mrs.fr

    2006-12-10

    The tumor necrosis factor-alpha (TNF) converting enzyme (ADAM17) is a metalloprotease-disintegrin responsible for the cleavage of several biologically active transmembrane proteins. However, the substrate specificity of ADAM17 and the regulation of its shedding activity are still poorly understood. Here, we report that during its transport through the Golgi apparatus, ADAM17 is included in cholesterol-rich membrane microdomains (lipid rafts) where its prodomain is cleaved by furin. Consequently, ADAM17 shedding activity is sequestered in lipid rafts, which is confirmed by the fact that metalloproteinase inhibition increases the proportion of ADAM17 substrates (TNF and its receptors TNFR1 and TNFR2) in lipid rafts. Membrane cholesterol depletion increases the ADAM17-dependent shedding of these substrates demonstrating the importance of lipid rafts in the control of this process. Furthermore, ADAM17 substrates are present in different proportions in lipid rafts, suggesting that the entry of each of these substrates in these particular membrane microdomains is specifically regulated. Our data support the idea that one of the mechanisms regulating ADAM17 substrate cleavage involves protein partitioning in lipid rafts.

  17. Altered in vivo activity of liposome-incorporated lipopolysaccharide and lipid A.

    PubMed Central

    Dijkstra, J; Mellors, J W; Ryan, J L

    1989-01-01

    We compared the abilities of free and liposome-incorporated Salmonella minnesota wild-type lipopolysaccharide (LPS) and lipid A to activate peritoneal macrophages and induce lethal toxicity in mice. Incorporation of lipid A into multilamellar vesicles resulted in a 100-fold-decreased potency to prime macrophages for phorbol myristate acetate-triggered release of H2O2. In addition, liposome incorporation reduced the lethality of LPS and lipid A at least 10-fold in dactinomycin-sensitized mice. Similar results were obtained with multilamellar liposomes delivered intravenously and when small unilamellar vesicles were employed. The observed difference in toxicity was not dependent on dactinomycin treatment, since a similar decrease was obtained with large doses of liposomal LPS in unsensitized mice. Control liposomes, prepared without LPS and lipid A, did not reduce the activities of the free compounds. The administration of a sublethal amount of liposomal LPS induced within 20 days, but not during the first week, tolerance to a subsequently injected lethal dose of free endotoxin. The latter observation suggests that early-phase tolerance is not the mechanism responsible for the reduced toxicity of liposomal LPS. These data show that liposomal LPS and lipid A have reduced endotoxic activity in vivo and are consistent with our hypothesis that a direct interaction of lipid A with appropriate plasma membrane components is necessary to efficiently trigger biologic responses. This interaction, however, is prevented by the stable insertion of LPS into the liposomal membrane. PMID:2807528

  18. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    NASA Astrophysics Data System (ADS)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  19. Activation of the lipid droplet controls the rate of lipolysis of triglycerides in the insect fat body.

    PubMed

    Patel, Rajesh T; Soulages, Jose L; Hariharasundaram, Balaji; Arrese, Estela L

    2005-06-17

    The hydrolysis of triglyceride (TG) stored in the lipid droplets of the insect fat body is under hormonal regulation by the adipokinetic hormone (AKH), which triggers a rapid activation cAMP-dependent kinase cascade (protein kinase A (PKA)). The role of phosphorylation on two components of the lipolytic process, the TG-lipase and the lipid droplet, was investigated in fat body adipocytes. The activity of purified TG-lipase determined using in vivo TG-radiolabeled lipid droplets was unaffected by the phosphorylation of the lipase. However, the activity of purified lipase was 2.4-fold higher against lipid droplets isolated from hormone-stimulated fat bodies than against lipid droplets isolated from unstimulated tissue. In vivo stimulation of lipolysis promotes a rapid phosphorylation of a lipid droplet protein with an apparent mass of 42-44 kDa. This protein was identified as "Lipid Storage Droplet Protein 1" (Lsdp1). In vivo phosphorylation of this protein reached a peak approximately 10 min after the injection of AKH. Supporting a role of Lsdp1 in lipolysis, maximum TG-lipase activity was also observed with lipid droplets isolated 10 min after hormonal stimulation. The activation of lipolysis was reconstituted in vitro using purified insect PKA and TG-lipase and lipid droplets. In vitro phosphorylation of lipid droplets catalyzed by PKA enhanced the phosphorylation of Lsdp1 and the lipolytic rate of the lipase, demonstrating a prominent role PKA and protein phosphorylation on the activation of the lipid droplets. AKH-induced changes in the properties of the substrate do not promote a tight association of the lipase with the lipid droplets. It is concluded that the lipolysis in fat body adipocytes is controlled by the activation of the lipid droplet. This activation is achieved by PKA-mediated phosphorylation of the lipid droplet. Lsdp1 is the main target of PKA, suggesting that this protein is a major player in the activation of lipolysis in insects.

  20. Effect of acetic acid on lipid accumulation by glucose-fed activated sludge cultures

    SciTech Connect

    Mondala, Andro; Hernandez, Rafael; French, Todd; McFarland, Linda; Sparks, Darrell; Holmes, William; Haque, Monica

    2012-01-01

    The effect of acetic acid, a lignocellulose hydrolysis by-product, on lipid accumulation by activated sludge cultures grown on glucose was investigated. This was done to assess the possible application of lignocellulose as low-cost and renewable fermentation substrates for biofuel feedstock production. Results: Biomass yield was reduced by around 54% at a 2 g L -1 acetic acid dosage but was increased by around 18% at 10 g L -1 acetic acid dosage relative to the control run. The final gravimetric lipid contents at 2 and 10 g L -1 acetic acid levels were 12.5 + 0.7% and 8.8 + 3.2% w/w, respectively, which were lower than the control (17.8 + 2.8% w/w). However, biodiesel yields from activated sludge grown with acetic acid (5.6 + 0.6% w/w for 2 g L -1 acetic acid and 4.2 + 3.0% w/w for 10 g L -1 acetic acid) were higher than in raw activated sludge (1-2% w/w). The fatty acid profiles of the accumulated lipids were similar with conventional plant oil biodiesel feedstocks. Conclusions: Acetic acid enhanced biomass production by activated sludge at high levels but reduced lipid production. Further studies are needed to enhance acetic acid utilization by activated sludge microorganisms for lipid biosynthesis.

  1. Tracking activity and function of microorganisms by stable isotope probing of membrane lipids.

    PubMed

    Wegener, Gunter; Kellermann, Matthias Y; Elvert, Marcus

    2016-10-01

    Microorganisms in soils and sediments are highly abundant and phylogenetically diverse, but their specific metabolic activity and function in the environment is often not well constrained. To address this critical aspect in environmental biogeochemistry, different methods involving stable isotope probing (SIP) and detection of the isotope label in a variety of molecular compounds have been developed. Here we review recent progress in lipid-SIP, a technique that combines the assimilation of specific (13)C-labeled metabolic substrates such as inorganic carbon, methane, glucose and amino acids into diagnostic membrane lipid compounds. Using the structural characteristics of certain lipid types in combination with genetic molecular techniques, the SIP approach reveals the activity and function of distinct microbial groups in the environment. More recently, deuterium labeling in the form of deuterated water (D2O) extended the lipid-SIP portfolio. Since lipid biosynthetic pathways involve hydrogen (H(+)) uptake from water, lipid production can be inferred from the detection of D-assimilation into these compounds. Furthermore, by combining D2O and (13)C-inorganic carbon (IC) labeling in a dual-SIP approach, rates of auto- and heterotrophic carbon fixation can be estimated. We discuss the design, analytical prerequisites, data processing and interpretation of single and dual-SIP experiments and highlight a case study on anaerobic methanotrophic communities inhabiting hydrothermally heated marine sediments.

  2. Mfge8 regulates enterocyte lipid storage by promoting enterocyte triglyceride hydrolase activity

    PubMed Central

    Khalifeh-Soltani, Amin; Gupta, Deepti; Ha, Arnold; Iqbal, Jahangir; Hussain, Mahmood; Podolsky, Michael J.

    2016-01-01

    The small intestine has an underappreciated role as a lipid storage organ. Under conditions of high dietary fat intake, enterocytes can minimize the extent of postprandial lipemia by storing newly absorbed dietary fat in cytoplasmic lipid droplets. Lipid droplets can be subsequently mobilized for the production of chylomicrons. The mechanisms that regulate this process are poorly understood. We report here that the milk protein Mfge8 regulates hydrolysis of cytoplasmic lipid droplets in enterocytes after interacting with the αvβ3 and αvβ5 integrins. Mice deficient in Mfge8 or the αvβ3 and αvβ5 integrins accumulate excess cytoplasmic lipid droplets after a fat challenge. Mechanistically, interruption of the Mfge8-integrin axis leads to impaired enterocyte intracellular triglyceride hydrolase activity in vitro and in vivo. Furthermore, Mfge8 increases triglyceride hydrolase activity through a PI3 kinase/mTORC2–dependent signaling pathway. These data identify a key role for Mfge8 and the αvβ3 and αvβ5 integrins in regulating enterocyte lipid processing. PMID:27812539

  3. Natural lipid nanoparticles containing nimesulide: synthesis, characterization and in vivo antiedematogenic and antinociceptive activities.

    PubMed

    Raffin, Renata P; Lima, Amanda; Lorenzoni, Ricardo; Antonow, Michelli B; Turra, Cláudia; Alves, Marta P; Fagan, Solange B

    2012-04-01

    Lipid nanoparticles are drug delivery systems able to increase bioavailability of poorly soluble drugs. They can be prepared with different lipid materials, especially natural lipids. Shea butter is a natural lipid obtained from the Butyrospermum parkii seed and rich in oleic and stearic acids. Nimesulide is a COX 2 selective anti-inflammatory that is poorly soluble in water. The purpose of this study was to develop and characterize shea butter lipid nanoparticles using a new technique and evaluate the in vivo activity of these nanoparticles. Lipid nanoparticles were prepared by melting shea butter and mixing with an aqueous phase using a high shear mixer. The nanoparticles presented pH of 6.9 +/- 0.1, mean particle size of 90 nm and a narrow polydispersity (0.21). Zeta potential was around -20 mV and the encapsulation efficiency was 97.5%. Drug release was evaluated using dialysis bags and presented monoexponential profile with t50% of 4.80 h (free drug t50% was only 2.86 h). Antinociceptive activity was performed by the acetic acid model. Both nimesulide and nimesulide-loaded nanoparticles presented significant activity compared to the control. The in vivo anti-inflammatory activity was evaluated by paw edema and was statistically different for the nanoparticles containing nimesulide compared to free nimesulide, blank nanoparticles and saline. In conclusion, the use of shea butter as encapsulating lipid was very successful and allowed nanoparticles to be prepared with a very simple technique. The nanoparticles presented significant pharmacological effects that were not seen for free drug administration.

  4. [Lipid peroxidation processes and activity of brain succinate dehydrogenase in experimental craniocerebral trauma].

    PubMed

    Demchuk, M L; Medvedev, A E; Promyslov, M Sh; Gorkin, V Z

    1993-01-01

    A statistically significant decrease in the activity of succinate dehydrogenase (SDH) was found in the rabbit brain after craniocerebral injury. The decrease in the activity of brain SDH was not shown to result from "competitive inhibition" by malonate accumulated after activation of lipid peroxidation. The activity of brain SDH was normalized by directed modification of the function of the central nervous system via administration of phenamine (amphetamine) into the injured animals.

  5. Searching for line active molecules on biphasic lipid monolayers.

    PubMed

    Bischof, Andrea Alejandra; Mangiarotti, Agustín; Wilke, Natalia

    2015-03-21

    In membranes with phase coexistence, line tension appears as an important parameter for the determination of the amount of domains, as well as their size and their shape, thus defining the membrane texture. Different molecules have been proposed as "linactants" (i.e. molecules that reduce the line tension, thereby modulating the membrane texture). In this work, we explore the efficiency of different molecules as linactants in monolayers with two coexisting phases of different thicknesses. We tested the linactant ability of a molecule with chains of different saturation degrees, another molecule with different chain lengths and a bulky molecule. In this way, we show in the same system the effect of molecules with chains of different rigidities, with an intrinsic thickness mismatch and with a bulky moiety, thereby analyzing different hypotheses of how a molecule may change the line tension in a monolayer system. Both lipids with different hydrocarbon chains did not act as linactants, while only one of the bulky molecules tested decreased the line tension in the monolayer studied. We conclude that there are no universal rules for the structure of a molecule that enable us to predict that it will behave as a linactant and thus, designing linactants appears to be a difficult task and a challenge for future studies. Furthermore, in regard to the membrane texture, there was no direct influence of the line tension in the distribution of domain sizes.

  6. Enhancement in antifungal activity of eugenol in immunosuppressed rats through lipid nanocarriers.

    PubMed

    Garg, A; Singh, S

    2011-10-15

    In the present study eugenol loaded solid lipid nanoparticles (SLN) was prepared and characterized for particle size, polydispersity index, zeta potential, encapsulation efficiency, in vitro release and in vivo antifungal activity. Effect of addition of liquid lipid (caprylic triglyceride) to solid lipid (stearic acid) on crystallinity of lipid matrix of SLN was determined by using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. Transmission electron microscopy (TEM) was carried out to determine the morphology of SLN. In vivo antifungal activity of eugenol loaded lipid nanoparticles was evaluated by using a model of oral candidiasis in immunosuppressed rats. Particle size results showed that d(90) of SLN(1) (single lipid matrix) and SLN(2) (binary lipid matrix) was 332±14.2 nm and 87.8±3.8 nm, respectively. Polydispersity index was found to be in the range of 0.27-0.4 which indicate moderate size distribution. Encapsulation efficiency of SLN(2) (98.52%) was found to be more than that of SLN(1) (91.80%) at same lipid concentration (2%, w/v). Increasing of the solid lipid concentration from 2% (w/v) to 4% (w/v) resulted in increase in encapsulation efficiency and the particle size. SLN(2) shows faster release of eugenol than that of SLN(1) due to smaller size and presence of liquid lipid which provide less barriers to the diffusion of drug from matrix. TEM study reveals the spherical shape of SLN. FT-IR, DSC and XRD results indicate less crystallinity of SLN(2) than that of SLN(1). In vivo studies show no significant difference in log cfu value of all the groups at 0 day. At 8th day, log cfu value of group treated with saline (control), standard antifungal agent, eugenol solution, SLN(1) and SLN(2) was found to be 3.89±.032, 2.69, 3.39±.088, 3.19±.028 and 3.08±0.124, respectively. The in vivo study results indicate improvement in the antifungal activity of eugenol when

  7. Improved tumor targeting and antitumor activity of camptothecin loaded solid lipid nanoparticles by preinjection of blank solid lipid nanoparticles.

    PubMed

    Jang, Dong-Jin; Moon, Cheol; Oh, Euichaul

    2016-05-01

    This study aimed to enhance the in vivo antitumor effects of camptothecin (CPT), a strong antitumor agent whose delivery is limited by poor aqueous solubility and instability of the active lactone form. CPT was loaded into sterically stabilized, solid lipid nanoparticles (CPT-SLNs) formulated for intravenous administration. The influence of preinjected blank SLNs on the tumor targeting, pharmacokinetics and antitumor activity of CPT-SLNs was investigated. The CPT-SLNs composed of trilaurin-based lipid matrix containing poloxamer188 and pegylated phospholipid as stabilizers were prepared by hot homogenization method and evaluated for in vitro characteristics and in vivo performance. The CPT-SLNs showed an in vitro long-term sustained release pattern and effectively protected the CPT lactone form from hydrolysis under physiological conditions. Notable tumor targeting and tumor growth inhibition were observed after intravenous administration of CPT-SLNs to mice with subcutaneous transplants of CT26 carcinoma cells. In pharmacokinetic studies in rats, CPT-SLNs markedly elevated plasma CPT level and prolonged blood circulation compared to free CPT. Nonetheless, high uptake of CPT-SLNs by reticuloendothelial system (RES)-rich tissues resulted in limited tumor targeting of CPT-SLNs and plasma CPT levels. Preinjection of blank SLNs before administration of CPT-SLNs to tumor-bearing mice substantially reduced the accumulation of CPT-SLNs in RES organs. This led to significantly enhanced tumor targeting, improved pharmacokinetic parameters and increased antitumor efficacy of CPT-SLNs. These results suggested that the in vivo antitumor effects of CPT-SLNs could be further enhanced by preinjection of blank SLNs. Therefore, CPT-SLNs with preinjected blank SLNs could be a potential approach for stable and effective CPT-based cancer therapy.

  8. Structure-activity exploration of a small-molecule Lipid II inhibitor.

    PubMed

    Fletcher, Steven; Yu, Wenbo; Huang, Jing; Kwasny, Steven M; Chauhan, Jay; Opperman, Timothy J; MacKerell, Alexander D; de Leeuw, Erik P H

    2015-01-01

    We have recently identified low-molecular weight compounds that act as inhibitors of Lipid II, an essential precursor of bacterial cell wall biosynthesis. Lipid II comprises specialized lipid (bactoprenol) linked to a hydrophilic head group consisting of a peptidoglycan subunit (N-acetyl glucosamine [GlcNAc]-N-acetyl muramic acid [MurNAc] disaccharide coupled to a short pentapeptide moiety) via a pyrophosphate. One of our lead compounds, a diphenyl-trimethyl indolene pyrylium, termed BAS00127538, interacts with the MurNAc moiety and the isoprenyl tail of Lipid II. Here, we report on the structure-activity relationship of BAS00127538 derivatives obtained by in silico analyses and de novo chemical synthesis. Our results indicate that Lipid II binding and bacterial killing are related to three features: the diphenyl moiety, the indolene moiety, and the positive charge of the pyrylium. Replacement of the pyrylium moiety with an N-methyl pyridinium, which may have importance in stability of the molecule, did not alter Lipid II binding or antibacterial potency.

  9. Paraoxonase Activity and Lipid Profile in Paediatric Nephrotic Syndrome: A Cross-sectional Study

    PubMed Central

    Patil, Anuradha B.; Patil, Vidya S.; Ingleshwar, Deepti G.

    2016-01-01

    Introduction Dyslipidaemia of Nephrotic Syndrome (NS) is known to be linked to oxidative reactions and atherosclerosis. Paraoxonase (PON1) has been implicated in the prevention of Low Density Lipoprotein (LDL) lipid peroxidation and also degrades biologically active oxidised lipids in lipoprotein. Aim The present study was taken up to assess PON1 levels in paediatric nephrotic syndrome and also to see if any correlation exists between lipid parameters and PON1. Materials and Methods This study consists of Group 1 with 40 cases of NS in the age group of 2-14 years and Group 2 with 40 age and sex matched healthy controls. Lipid profile and paraoxonase activity was measured in serum samples of both the groups. Results Statistical analysis by student’s t-test showed that the mean levels of Total Cholesterol, Trigylycerides, LDL, and VLDL were significantly increased in Group 1 when compared to Group 2 (p <0.001). The mean levels of HDL were similar in both groups. The levels of PON1 were significantly lowered in Group 1 when compared to Group 2. Correlation studies showed no significant correlation between lipid profile and PON1. Conclusion Cases have atherosclerotic dyslipidaemia and significantly decreased PON1 activity. Decreased PON1 may lead to increased oxidation of LDL accelerating the process of atherosclerosis. PMID:27134858

  10. Cefuroxime axetil loaded solid lipid nanoparticles for enhanced activity against S. aureus biofilm.

    PubMed

    Singh, Bhupender; Vuddanda, Parameswara Rao; M R, Vijayakumar; Kumar, Vinod; Saxena, Preeti S; Singh, Sanjay

    2014-09-01

    The present research work is focused on the development of solid lipid nanoparticles of cefuroxime axetil (CA-SLN) for its enhanced inhibitory activity against Staphylococcus aureus produced biofilm. CA-SLN was prepared by solvent emulsification/evaporation method using single lipid (stearic acid (SA)) and binary lipids (SA and tristearin (TS)). Process variables such as volume of dispersion medium, concentration of surfactant, homogenization speed and time were optimized. The prepared SLN were characterized for encapsulation efficiency, drug polymer interaction studies (DSC and FT-IR), shape and surface morphology (SEM and AFM), in vitro drug release, stability studies and in vitro anti biofilm activity against S. aureus biofilm. Among the process variables, increased volume of dispersion medium, homogenization speed and time led to increase in particle size whereas increase in surfactant concentration decreased the particle size. SLN prepared using binary lipids exhibited higher entrapment efficiency than the single lipid. DSC and FT-IR studies showed no incompatible interaction between drug and excipients. CA-SLN showed two folds higher anti-biofilm activity in vitro than pristine CA against S. aureus biofilm.

  11. Anti lipid peroxidation activity of Piper trioicum Roxb. and Physalis minima L. extracts.

    PubMed

    Dinakaran, Sathis Kumar; Saraswathi, Narasimha Raju; Nalini, Venkata Rama Rao; Srisudharson; Bodanapu, Venkat Ram Reddy; Avasarala, Harani; Banji, David

    2011-07-01

    Attempt has been made to evaluate free radical scavenging activity of ethanolic extract of Piper trioicum Roxb. and Physalis minima L. individually. In this study goat liver has been used as lipid source. This in vitro evaluation was done by measuring the malondialdehyde (MDA) of tissue homogenates. The results suggest that the ethanolic extract of the Piper trioicum Roxb. and Physalis minima L. has the ability to suppress the lipid peroxidation and it was also found that Piper trioicum Roxb. extract has more activity than Physalis minima L. extract.

  12. Elevated CETP Lipid Transfer Activity is Associated with the Risk of Venous Thromboembolism

    PubMed Central

    Deguchi, Hiroshi; Banerjee, Yajnavalka; Elias, Darlene J.

    2016-01-01

    Aim: Cholesteryl ester transfer protein (CETP) is an important lipid transfer factor in plasma that enhances prothrombinase activity in purified systems. This study was conducted to test the association of plasma CETP activity with venous thrombosis (VTE) and to address the procoagulant mechanism of CETP activity in prothrombinase assays. Methods: We measured CETP lipid transfer activity in plasmas of 49 male VTE patients and in plasmas of matched controls. CETP procoagulant activity was tested in purified prothrombinase systems. Results: CETP lipid transfer activity levels were significantly higher in VTE patients than in controls (p = 0.0008). A subset of patients carrying the CETP mutations Ala373Pro and Arg451Gln, which were also linked to the VTE risk, showed significantly higher plasma CETP activity than the non-carriers. The plasma CETP activity negatively correlated with APTT, suggesting that the CETP activity is associated with plasma coagulability. Recombinant (r) CETP bound to both factor Xa (Kd = 15 nM) and Gla-domainless factor Xa (Kd = 59 nM), whereas rCETP enhanced prothrombin activation by factor Xa, but not by Gla-domainless factor Xa. rCETP also required factor Va for enhancement of prothrombinase activity. When we addressed the effects of mutations in CETP on prothrombinase activity, Gln451-rCETP was found to have five-fold higher thrombin generation activity than wt-rCETP or Pro373-rCETP. Conclusions: Elevated CETP lipid transfer activity in plasma was associated with the risk of VTE. Gln451-CETP, which is linked to VTE, has much higher procoagulant activity than wt-CETP. CETP might act as a physiologic procoagulant by mechanisms that involve its direct binding to factor Xa. PMID:27169917

  13. Lipid IVa incompletely activates MyD88-independent Toll-like receptor 4 signaling in mouse macrophage cell lines.

    PubMed

    Ogura, Norihiko; Muroi, Masashi; Sugiura, Yuka; Tanamoto, Ken-ichi

    2013-04-01

    We investigated the difference in the effect of synthetic lipid A compounds on MyD88-dependent and -independent Toll-like receptor 4 (TLR4) signaling in mouse macrophage cells. At higher concentrations, Escherichia coli-type hexa-acylated lipid A 506, Salmonella-type hepta-acylated lipid A 516, the lipid A precursor lipid IVa and monophosphoryl lipid A induced similar levels of production of the MyD88-dependent cytokine IL-1β although their potencies varied, whereas the maximum production of the MyD88-independent cytokine RANTES induced by lipid IVa was less than 50% that of other lipid A compounds. A maximum level of NF-κB activation, which is involved in IL-1β gene transcription, was also induced to a similar level by these four lipid A compounds, while the maximum level of IFN-β promoter activity induced during MyD88-independent signaling was also less than 50% for lipid IVa stimulation compared with other lipid A compounds. Early IκBα phosphorylation activated by MyD88-dependent signaling was similarly induced by 506 and lipid IVa, whereas lipid IVa barely stimulated the phosphorylation of IRF3, a MyD88-independent transcription factor, although efficient phosphorylation was observed with 506 stimulation. These results indicate that lipid IVa has limited activity toward MyD88-independent signaling of TLR4, in macrophage cell lines, despite having efficient activity in the MyD88-dependent pathway.

  14. Activation of protein kinase C by the lipid moieties of lipopolysaccharide

    SciTech Connect

    Wightman, P.D.; Raetz, C.R.H.

    1986-03-01

    Protein kinase C (PKC) was partially purified from the RAW264.7 macrophage-like cell and characterized by its activation by phosphatidylserine (PS) in the presence of calcium and its insensitivity to cyclic nucleotides or calmodulin. This PKC can also be activated by the acidic lipid moieties of lipopolysaccharide (LPS). The LPS lipids activate PKC in the absence of PS and, like PS, synergize with diacylglycerol (DAG). Intact RAW264.7 cells were prelabelled with /sup 32/Pi and treated with the well characterized PKC ligands, phorbol myristate acetate (PMA) or DAG. The phosphoproteins thereby induced were separated in 2-D gels and visualized by autoradiography. These phosphoproteins were used as standards to identify the PKC-associated phosphoproteins induced in these cells using other stimulators. The authors demonstrate that the LPS lipids as well as LPS itself induce the formation of phosphoproteins common to those induced by PMA or DAG. PMA, DAG, the LPS lipids, and LPS itself activate the RAW264.7 cell and stimulate the release of prostaglandin D/sub 2/ at the same concentration that stimulate new protein phosphorylation. These results suggest that the activation of PKC is an early event in the activation of the RAW264.7 macrophage by LPS.

  15. Glass-supported lipid/polydiacetylene films for colour sensing of membrane-active compounds.

    PubMed

    Volinsky, Roman; Kliger, Mark; Sheynis, Tania; Kolusheva, Sofiya; Jelinek, Raz

    2007-06-15

    Glass-supported biomimetic lipid/polydiacetylene films were employed for colourimetric detection and analysis of amphiphilic and membrane-active molecules. The sensor films comprise lipid monolayers that constitute a biomimetic membrane platform, interspersed within polydiacetylene domains that function as the colour reporter. The optical detection scheme is based on visible blue-red transitions of polydiacetylene, induced by amphiphilic analytes interacting with the film. The colour transitions of the lipid/polydiacetylene films can be either detected by the naked eye, recorded spectroscopically, or registered through digital image analysis using conventional scanning devices. Digital image analysis, in particular, allows quantification of the colourimetric transformations. Detection threshold of micromolar concentration of a membrane-active cytolytic peptide is demonstrated.

  16. Electrosprayed core-shell polymer-lipid nanoparticles for active component delivery.

    PubMed

    Eltayeb, Megdi; Stride, Eleanor; Edirisinghe, Mohan

    2013-11-22

    A key challenge in the production of multicomponent nanoparticles for healthcare applications is obtaining reproducible monodisperse nanoparticles with the minimum number of preparation steps. This paper focus on the use of electrohydrodynamic (EHD) techniques to produce core-shell polymer-lipid structures with a narrow size distribution in a single step process. These nanoparticles are composed of a hydrophilic core for active component encapsulation and a lipid shell. It was found that core-shell nanoparticles with a tunable size range between 30 and 90 nm and a narrow size distribution could be reproducibly manufactured. The results indicate that the lipid component (stearic acid) stabilizes the nanoparticles against collapse and aggregation and improves entrapment of active components, in this case vanillin, ethylmaltol and maltol. The overall structure of the nanoparticles produced was examined by multiple methods, including transmission electron microscopy and differential scanning calorimetry, to confirm that they were of core-shell form.

  17. Electrosprayed core-shell polymer-lipid nanoparticles for active component delivery

    NASA Astrophysics Data System (ADS)

    Eltayeb, Megdi; Stride, Eleanor; Edirisinghe, Mohan

    2013-11-01

    A key challenge in the production of multicomponent nanoparticles for healthcare applications is obtaining reproducible monodisperse nanoparticles with the minimum number of preparation steps. This paper focus on the use of electrohydrodynamic (EHD) techniques to produce core-shell polymer-lipid structures with a narrow size distribution in a single step process. These nanoparticles are composed of a hydrophilic core for active component encapsulation and a lipid shell. It was found that core-shell nanoparticles with a tunable size range between 30 and 90 nm and a narrow size distribution could be reproducibly manufactured. The results indicate that the lipid component (stearic acid) stabilizes the nanoparticles against collapse and aggregation and improves entrapment of active components, in this case vanillin, ethylmaltol and maltol. The overall structure of the nanoparticles produced was examined by multiple methods, including transmission electron microscopy and differential scanning calorimetry, to confirm that they were of core-shell form.

  18. Lipid constituents of the edible mushroom, Pleurotus giganteus demonstrate anti-Candida activity.

    PubMed

    Phan, Chia-Wei; Lee, Guan-Serm; Macreadie, Ian G; Malek, Sri Nurestri Abd; Pamela, David; Sabaratnam, Vikineswary

    2013-12-01

    Different solvent extracts of Pleurotus giganteus fruiting bodies were tested for antifungal activities against Candida species responsible for human infections. The lipids extracted from the ethyl acetate fraction significantly inhibited the growth of all the Candida species tested. Analysis by GC/MS revealed lipid components such as fatty acids, fatty acid methyl esters, ergosterol, and ergosterol derivatives. The sample with high amounts of fatty acid methyl esters was the most effective antifungal agent. The samples were not cytotoxic to a mammalian cell line, mouse embryonic fibroblasts BALB/c 3T3 clone A31. To our knowledge, this is the first report of antifungal activity of the lipid components of Pleurotus giganteus against Candida species.

  19. Correlation among lung damage after radiation, amount of lipid peroxides, and antioxidant enzyme activities

    SciTech Connect

    Nozue, M.; Ogata, T.

    1989-04-01

    The correlation between lipid peroxidation and morphologic changes was examined in Sprague-Dawley rat lungs after 30 Gy single thoracic radiation. The rats were sacrificed every week until the end of the fifth week after radiation. The left lungs were used for the measurement of lipid peroxides and antioxidant enzymes activities. The right lungs were examined by light and electron microscopy. Amounts of lung lipid peroxides were within normal limits, and no cellular degenerative changes were observed in the lungs except for subendothelial and interstitial edema 2 weeks after radiation. Lipid peroxides drastically increased and marked degenerative cellular changes such as edematous swelling, vacuolation, and destruction of cell membranes occurred in the alveolar septa following the third week after radiation. The activities of catalase were significantly higher during the period from the second to the fifth week and those of superoxide dismutase and glutathione peroxidase increased at the end of the fifth week. Our results demonstrated that the acceleration of lipid peroxidation was well correlated with the morphologic expression of cell injury in the irradiated lungs.

  20. V-ATPase and osmotic imbalances activate endolysosomal LC3 lipidation

    PubMed Central

    Florey, Oliver; Gammoh, Noor; Kim, Sung Eun; Jiang, Xuejun; Overholtzer, Michael

    2014-01-01

    Recently a noncanonical activity of autophagy proteins has been discovered that targets lipidation of microtubule-associated protein 1 light chain 3 (LC3) onto macroendocytic vacuoles, including macropinosomes, phagosomes, and entotic vacuoles. While this pathway is distinct from canonical autophagy, the mechanism of how these nonautophagic membranes are targeted for LC3 lipidation remains unclear. Here we present evidence that this pathway requires activity of the vacuolar-type H+-ATPase (V-ATPase) and is induced by osmotic imbalances within endolysosomal compartments. LC3 lipidation by this mechanism is induced by treatment of cells with the lysosomotropic agent chloroquine, and through exposure to the Heliobacter pylori pore-forming toxin VacA. These data add novel mechanistic insights into the regulation of noncanonical LC3 lipidation and its associated processes, including LC3-associated phagocytosis (LAP), and demonstrate that the widely and therapeutically used drug chloroquine, which is conventionally used to inhibit autophagy flux, is an inducer of LC3 lipidation. PMID:25484071

  1. Phosphatidylserine lipids and membrane order precisely regulate the activity of Polybia-MP1 peptide.

    PubMed

    Alvares, Dayane S; Neto, João Ruggiero; Ambroggio, Ernesto E

    2017-03-05

    Polybia-MP1 (IDWKKLLDAAKQIL-NH2) is a lytic peptide from the Brazilian wasp venom with known anti-cancer properties. Previous evidence indicates that phosphatidylserine (PS) lipids are relevant for the lytic activity of MP1. In agreement with this requirement, phosphatidylserine lipids are translocated to the outer leaflet of cells, and are available for MP1 binding, depending on the presence of liquid-ordered domains. Here, we investigated the effect of PS on MP1 activity when this lipid is reconstituted in membranes of giant or large liposomes with different lipid-phase states. By monitoring the membrane and soluble luminal content of giant unilamellar vesicles (GUVs), using fluorescence confocal microscopy, we were able to determine that MP1 has a pore-forming activity at the membrane level. Liquid-ordered domains, which were phase-separated within the membrane of GUVs, influenced the pore-forming activity of MP1. Experiments evaluating the membrane-binding and lytic activity of MP1 on large unilamellar vesicles (LUVs), with the same lipid composition as GUVs, demonstrated that there was synergy between liquid-ordered domains and PS, which enhanced both activities. Based on our findings, we propose that the physicochemical properties of cancer cell membranes, which possess a much higher concentration of PS than normal cells, renders them susceptible to MP1 binding and lytic pore formation. These results can be correlated with MP1's potent and selective anti-cancer activity and pave the way for future research to develop cancer therapies that harness and exploit the properties of MP1.

  2. Evidence for Lipid Packaging in the Crystal Structure of the GM2-Activator Complex with Platelet Activating Factor

    SciTech Connect

    Wright, Christine S.; Mi, Li-Zhi; Rastinejad, Fraydoon

    2010-11-16

    GM2-activator protein (GM2-AP) is a lipid transfer protein that has the ability to stimulate the enzymatic processing of gangliosides as well as T-cell activation through lipid presentation. Our previous X-ray crystallographic studies of GM2-AP have revealed a large lipid binding pocket as the central overall feature of the structure with non-protein electron density within this pocket suggesting bound lipid. To extend these studies, we present here the 2 {angstrom} crystal structure of GM2-AP complexed with platelet activating factor (PAF). PAF is a potent phosphoacylglycerol whose toxic patho-physiological effects can be inhibited by GM2-AP. The structure shows an ordered arrangement of two bound lipids and a fatty acid molecule. One PAF molecule binds in an extended conformation within the hydrophobic channel that has an open and closed conformation, and was seen to contain bound phospholipid in the low pH apo structure. The second molecule is submerged inside the pocket in a U-shaped conformation with its head group near the single polar residue S141. It was refined as lyso-PAF as it lacks electron density for the sn-2 acetate group. The alkyl chains of PAF interact through van der Waals contacts, while the head groups bind in different environments with their phosphocholine moieties in contact with aromatic rings (Y137, F80). The structure has revealed further insights into the lipid binding properties of GM2-AP, suggesting an unexpected unique mode of lipid packaging that may explain the efficiency of GM2-AP in inhibiting the detrimental biological effects of PAF.

  3. Hydration in Lipid Monolayers: Correlation of Water Activity and Surface Pressure.

    PubMed

    Disalvo, E Anibal; Hollmann, Axel; Martini, M Florencia

    2015-01-01

    In order to give a physical meaning to each region of the membrane we define the interphase as the region in a lipid membrane corresponding to the polar head groups imbibed in water with net different properties than the hydrocarbon region and the water phase. The interphase region is analyzed under the scope of thermodynamics of surface and solutions based on the definition of Defay-Prigogine of an interphase and the derivation that it has in the understanding of membrane processeses in the context of biological response. In the view of this approach, the complete monolayer is considered as the lipid layer one molecule thick plus the bidimensional solution of the polar head groups inherent to it (the interphase region). Surface water activity appears as a common factor for the interaction of several aqueous soluble and surface active proteins with lipid membranes of different composition. Protein perturbation can be measured by changes in the surface pressure of lipid monolayers at different initial water surface activities. As predicted by solution chemistry, the increase of surface pressure is independent of the particle nature that dissolves. Therefore, membranes give a similar response in terms of the determined surface states given by water activity independent of the protein or peptide.

  4. Ether lipid-ester prodrugs of acyclic nucleoside phosphonates: activity against adenovirus replication in vitro.

    PubMed

    Hartline, Caroll B; Gustin, Kortney M; Wan, William B; Ciesla, Stephanie L; Beadle, James R; Hostetler, Karl Y; Kern, Earl R

    2005-02-01

    The acyclic nucleoside phosphonate cidofovir (CDV) and its closely related analogue (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)-adenine ([S]-HPMPA) have been reported to have activity against many adenovirus (AdV) serotypes. A new series of orally active ether lipid-ester prodrugs of CDV and of (S)-HPMPA that have slight differences in the structure of their lipid esters were evaluated, in tissue-culture cells, for activity against 5 AdV serotypes. The results indicated that, against several AdV serotypes, the most active compounds were 15-2500-fold more active than the unmodified parent compounds and should be evaluated further for their potential to treat AdV infections in humans.

  5. Progression of NMR studies of membrane-active peptides from lipid bilayers to live cells

    NASA Astrophysics Data System (ADS)

    Sani, M.-A.; Separovic, F.

    2015-04-01

    Understanding the structure of membrane-active peptides faces many challenges associated with the development of appropriate model membrane systems as the peptide structure depends strongly on the lipid environment. This perspective provides a brief overview of the approach taken to study antimicrobial and amyloid peptides in phospholipid bilayers using oriented bilayers and magic angle spinning techniques. In particular, Boltzmann statistics REDOR and maximum entropy analysis of spinning side bands are used to analyse systems where multiple states of peptide or lipid molecules may co-exist. We propose that in future, rather than model membranes, structural studies in whole cells are feasible.

  6. Lipid selectivity in novel antimicrobial peptides: Implication on antimicrobial and hemolytic activity.

    PubMed

    Maturana, P; Martinez, M; Noguera, M E; Santos, N C; Disalvo, E A; Semorile, L; Maffia, P C; Hollmann, A

    2017-05-01

    Antimicrobial peptides (AMPs) are small cationic molecules that display antimicrobial activity against a wide range of bacteria, fungi and viruses. For an AMP to be considered as a therapeutic option, it must have not only potent antibacterial properties but also low hemolytic and cytotoxic activities [1]. Even though many studies have been conducted in order to correlate the antimicrobial activity with affinity toward model lipid membranes, the use of these membranes to explain cytotoxic effects (especially hemolysis) has been less explored. In this context, we studied lipid selectivity in two related novel AMPs, peptide 6 (P6) and peptide 6.2 (P6.2). Each peptide was designed from a previously reported AMP, and specific amino acid replacements were performed in an attempt to shift their hydrophobic moment or net charge. P6 showed no antimicrobial activity and high hemolytic activity, and P6.2 exhibited good antibacterial and low hemolytic activity. Using both peptides as a model we correlated the affinity toward membranes of different lipid composition and the antimicrobial and hemolytic activities. Our results from surface pressure and zeta potential assays showed that P6.2 exhibited a higher affinity and faster binding kinetic toward PG-containing membranes, while P6 showed this behavior for pure PC membranes. The final position and structure of P6.2 into the membrane showed an alpha-helix conversion, resulting in a parallel alignment with the Trps inserted into the membrane. On the other hand, the inability of P6 to adopt an amphipathic structure, plus its lower affinity toward PG-containing membranes seem to explain its poor antimicrobial activity. Regarding erythrocyte interactions, P6 showed the highest affinity toward erythrocyte membranes, resulting in an increased hemolytic activity. Overall, our data led us to conclude that affinity toward negatively charged lipids instead of zwitterionic ones seems to be a key factor that drives from hemolytic to

  7. Bioconversion of volatile fatty acids derived from waste activated sludge into lipids by Cryptococcus curvatus.

    PubMed

    Liu, Jia; Liu, Jia-Nan; Yuan, Ming; Shen, Zi-Heng; Peng, Kai-Ming; Lu, Li-Jun; Huang, Xiang-Feng

    2016-07-01

    Pure volatile fatty acid (VFA) solution derived from waste activated sludge (WAS) was used to produce microbial lipids as culture medium in this study, which aimed to realize the resource recovery of WAS and provide low-cost feedstock for biodiesel production simultaneously. Cryptococcus curvatus was selected among three oleaginous yeast to produce lipids with VFAs derived from WAS. In batch cultivation, lipid contents increased from 10.2% to 16.8% when carbon to nitrogen ratio increased from about 3.5 to 165 after removal of ammonia nitrogen by struvite precipitation. The lipid content further increased to 39.6% and the biomass increased from 1.56g/L to 4.53g/L after cultivation for five cycles using sequencing batch culture (SBC) strategy. The lipids produced from WAS-derived VFA solution contained nearly 50% of monounsaturated fatty acids, including palmitic acid, heptadecanoic acid, ginkgolic acid, stearic acid, oleic acid, and linoleic acid, which showed the adequacy of biodiesel production.

  8. Natural compounds regulate energy metabolism by the modulating the activity of lipid-sensing nuclear receptors.

    PubMed

    Goto, Tsuyoshi; Kim, Young-Il; Takahashi, Nobuyuki; Kawada, Teruo

    2013-01-01

    Obesity causes excess fat accumulation in various tissues, most notoriously in the adipose tissue, along with other insulin-responsive organs such as skeletal muscle and the liver, which predisposes an individual to the development of metabolic abnormalities. The molecular mechanisms underlying obesity-induced metabolic abnormalities have not been completely elucidated; however, in recent years, the search for therapies to prevent the development of obesity and obesity-associated metabolic disorders has increased. It is known that several nuclear receptors, when activated by specific ligands, regulate carbohydrate and lipid metabolism at the transcriptional level. The expression of lipid metabolism-related enzymes is directly regulated by the activity of various nuclear receptors via their interaction with specific response elements in promoters of those genes. Many natural compounds act as ligands of nuclear receptors and regulate carbohydrate and lipid metabolism by regulating the activities of these nuclear receptors. In this review, we describe our current knowledge of obesity, the role of lipid-sensing nuclear receptors in energy metabolism, and several examples of food factors that act as agonists or antagonists of nuclear receptors, which may be useful for the management of obesity and the accompanying energy metabolism abnormalities.

  9. A model for the interfacial kinetics of phospholipase D activity on long-chain lipids.

    PubMed

    Majd, Sheereen; Yusko, Erik C; Yang, Jerry; Sept, David; Mayer, Michael

    2013-07-02

    The membrane-active enzyme phospholipase D (PLD) catalyzes the hydrolysis of the phosphodiester bond in phospholipids and plays a critical role in cell signaling. This catalytic reaction proceeds on lipid-water interfaces and is an example of heterogeneous catalysis in biology. Recently we showed that planar lipid bilayers, a previously unexplored model membrane for these kinetic studies, can be used for monitoring interfacial catalytic reactions under well-defined experimental conditions with chemical and electrical access to both sides of the lipid membrane. Employing an assay that relies on the conductance of the pore-forming peptide gramicidin A to monitor PLD activity, the work presented here reveals the kinetics of hydrolysis of long-chain phosphatidylcholine lipids in situ. We have developed an extension of a basic kinetic model for interfacial catalysis that includes product activation and substrate depletion. This model describes the kinetic behavior very well and reveals two kinetic parameters, the specificity constant and the interfacial quality constant. This approach results in a simple and general model to account for product accumulation in interfacial enzyme kinetics.

  10. Structural elucidation of olive pomace fed sea bass (Dicentrarchus labrax) polar lipids with cardioprotective activities.

    PubMed

    Nasopoulou, Constantina; Smith, Terry; Detopoulou, Maria; Tsikrika, Constantina; Papaharisis, Leonidas; Barkas, Dimitris; Zabetakis, Ioannis

    2014-02-15

    The purpose of this study was to structurally characterise the polar lipids of sea bass (Dicentrarchus labrax), fed with an experimental diet containing olive pomace (OP), that exhibit cardioprotective activities. OP has been added to conventional fish oil (FO) feed at 4% and this was the OP diet, having been supplemented as finishing diet to fish. Sea bass was aquacultured using either FO or OP diet. At the end of the dietary experiment, lipids in both samples of fish muscle were quantified and HPLC fractionated. The in vitro cardioprotective properties of the polar lipid fractions, using washed rabbit's platelets, have been assessed and the two most biologically active fractions were further analysed by mass spectrometry. The gas-chromatrograpy-mass spectrometric data shows that these two fractions contain low levels of myristic (14:0), oleic (18:1 cis ω-9) and linoleic acids (18:2 ω-6), but high levels of palmitic (16:0) and stearic acids (18:0) as well as eicosadienoic acid (20:2 ω-6). The first fraction (MS1) also contained significant levels of arachidonic acid (20:4 ω-6) and the omega-3 fatty acids: eicosapentaenoic acid (22:5) and docosahexaenoic acid (22:6). Electrospray-mass spectrometry elucidated that the lipid composition of the two fractions contained various diacyl-glycerophospholipids species, where the majority of them have either 18:0 or 18:1 fatty acids in the sn-1 position and either 22:6 or 20:2 fatty acids in the sn-2 position for MS1 and MS2, respectively. Our research focuses on the structure/function relationship of fish muscle polar lipids and cardiovascular diseases and structural data are given for polar lipid HPLC fractions with strong cardioprotective properties.

  11. Immunobiological activities of synthetic lipid A analogs and related compounds as compared with those of bacterial lipopolysaccharide, re-glycolipid, lipid A, and muramyl dipeptide.

    PubMed Central

    Kotani, S; Takada, H; Tsujimoto, M; Ogawa, T; Mori, Y; Sakuta, M; Kawasaki, A; Inage, M; Kusumoto, S; Shiba, T; Kasai, N

    1983-01-01

    Thirteen acylated and phosphorylated derivatives of beta-1,6-linked glucosamine disaccharide (lipid A analogs), which were synthesized after the structural model of Salmonella-type lipid A, and seven similar derivatives of glucosamine monosaccharide (lipid A-related compounds) were studied for their immunobiological activities. These included mitogenicity and polyclonal B cell activation enhancement of migration of monocytes and polymorphonuclear leukocytes derived from human peripheral blood, stimulation of guinea pig peritoneal macrophages, activation of human complement, and stimulation of serum antibody production and induction of delayed-type hypersensitivity against ovalbumin in guinea pigs. Comparisons were made with lipid A, RE-glycolipid, lipopolysaccharide of natural sources, and a well-known synthetic adjuvant, N-acetylmuramyl-L-alanyl-D-isoglutamine. Some of the lipid A analogs were found to manifest the mitogenic, polyclonal B cell-activating macrophage-stimulating, complement-activating, and immunostimulating activities, although the observed activities were generally far less than those of natural products in intensity and efficiency. Other immunobiological effects exhibited by most of the synthetic lipid A analogs were the enhancement of migration of monocytes and polymorphonuclear leukocytes. It is premature to draw definite conclusions on structure-activity relationships, since a few compounds which were active in some assay systems were scarcely active in other assays. However, an indisputable fact was that beta-1,6-glucosamine disaccharide 1 alpha,4'-diphosphate, which carries two amide-bound (R)-3-hydroxytetradecanoyl and three ester-bound tetradecanoyl residues, and thus has the structure most closely resembling natural lipid A among test compounds in this study, was definitely active in all of the present assay systems. However, its potency was generally much less than natural products. Some of glucosamine monosaccharide derivatives

  12. Nur77 modulates hepatic lipid metabolism through suppression of SREBP1c activity

    SciTech Connect

    Pols, Thijs W.H.; Ottenhoff, Roelof; Vos, Mariska; Levels, Johannes H.M.; Quax, Paul H.A.; Meijers, Joost C.M.; Pannekoek, Hans; Groen, Albert K.; Vries, Carlie J.M. de

    2008-02-22

    NR4A nuclear receptors are induced in the liver upon fasting and regulate hepatic gluconeogenesis. Here, we studied the role of nuclear receptor Nur77 (NR4A1) in hepatic lipid metabolism. We generated mice expressing hepatic Nur77 using adenoviral vectors, and demonstrate that these mice exhibit a modulation of the plasma lipid profile and a reduction in hepatic triglyceride. Expression analysis of >25 key genes involved in lipid metabolism revealed that Nur77 inhibits SREBP1c expression. This results in decreased SREBP1c activity as is illustrated by reduced expression of its target genes stearoyl-coA desaturase-1, mitochondrial glycerol-3-phosphate acyltransferase, fatty acid synthase and the LDL receptor, and provides a mechanism for the physiological changes observed in response to Nur77. Expression of LXR target genes Abcg5 and Abcg8 is reduced by Nur77, and may suggest involvement of LXR in the inhibitory action of Nur77 on SREBP1c expression. Taken together, our study demonstrates that Nur77 modulates hepatic lipid metabolism through suppression of SREBP1c activity.

  13. Ethanol alters cellular activation and CD14 partitioning in lipid rafts

    SciTech Connect

    Dai Qun; Zhang Jun; Pruett, Stephen B. . E-mail: spruet@lsuhsc.edu

    2005-06-24

    Alcohol consumption interferes with innate immunity. In vivo EtOH administration suppresses cytokine responses induced through Toll-like receptor 4 (TLR4) and inhibits TLR4 signaling. Actually, EtOH exhibits a generalized suppressive effect on signaling and cytokine responses induced by through most TLRs. However, the underlying mechanism remains unknown. RAW264.7 cells were treated with LPS or co-treated with EtOH or with lipid raft-disrupting drugs. TNF-{alpha} production, IRAK-1 activation, and CD14 partition were evaluated. EtOH or nystatin, a lipid raft-disrupting drug, suppressed LPS-induced production of TNF-{alpha}. The suppressive effect of EtOH on LPS-induced TNF-{alpha} production was additive with that of methyl-{beta}-cyclodextrin (MCD), another lipid raft-disrupting drug. EtOH interfered with IRAK-1 activation, an early TLR4 intracellular signaling event. Cell fractionation analyses show that acute EtOH altered LPS-related partition of CD14, a critical component of the LPS receptor complex. These results suggest a novel mechanism of EtOH action that involves interference with lipid raft clustering induced by LPS. This membrane action of EtOH might be one of the mechanisms by which EtOH acts as a generalized suppressor for TLR signaling.

  14. A fluorescence-activated cell sorting-based strategy for rapid isolation of high-lipid Chlamydomonas mutants.

    PubMed

    Terashima, Mia; Freeman, Elizabeth S; Jinkerson, Robert E; Jonikas, Martin C

    2015-01-01

    There is significant interest in farming algae for the direct production of biofuels and valuable lipids. Chlamydomonas reinhardtii is the leading model system for studying lipid metabolism in green algae, but current methods for isolating mutants of this organism with a perturbed lipid content are slow and tedious. Here, we present the Chlamydomonas high-lipid sorting (CHiLiS) strategy, which enables enrichment of high-lipid mutants by fluorescence-activated cell sorting (FACS) of pooled mutants stained with the lipid-sensitive dye Nile Red. This method only takes 5 weeks from mutagenesis to mutant isolation. We developed a staining protocol that allows quantification of lipid content while preserving cell viability. We improved separation of high-lipid mutants from the wild type by using each cell's chlorophyll fluorescence as an internal control. We initially demonstrated 20-fold enrichment of the known high-lipid mutant sta1 from a mixture of sta1 and wild-type cells. We then applied CHiLiS to sort thousands of high-lipid cells from a pool of about 60,000 mutants. Flow cytometry analysis of 24 individual mutants isolated by this approach revealed that about 50% showed a reproducible high-lipid phenotype. We further characterized nine of the mutants with the highest lipid content by flame ionization detection and mass spectrometry lipidomics. All mutants analyzed had a higher triacylglycerol content and perturbed whole-cell fatty acid composition. One arbitrarily chosen mutant was evaluated by microscopy, revealing larger lipid droplets than the wild type. The unprecedented throughput of CHiLiS opens the door to a systems-level understanding of green algal lipid biology by enabling genome-saturating isolation of mutants in key genes.

  15. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    SciTech Connect

    Souza, Sandra C.; Chau, Mary D.L.; Yang, Qing; Gauthier, Marie-Soleil; Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper; Dole, William P.

    2011-07-08

    Highlights: {yields} Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). {yields} ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. {yields} ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. {yields} Exposure of human adipocytes to fatty acids and (TNF{alpha}) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and

  16. Synthetic lipid A with endotoxic and related biological activities comparable to those of a natural lipid A from an Escherichia coli re-mutant.

    PubMed Central

    Kotani, S; Takada, H; Tsujimoto, M; Ogawa, T; Takahashi, I; Ikeda, T; Otsuka, K; Shimauchi, H; Kasai, N; Mashimo, J

    1985-01-01

    A synthetic compound (506), beta (1-6) D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated at 2'-amino and 3'-hydroxyl groups with (R)-3-dodecanoyloxytetradecanoyl and (R)-3-tetradecanoyloxytetradecanoyl groups, respectively, and has (R)-3-hydroxytetradecanoyl groups at 2-amino and 3-hydroxyl groups, exhibited full endotoxic activities identical to or sometimes stronger than those of a reference lipid A from an Escherichia coli Re-mutant (strain F515). Endotoxic activities tested include pyrogenicity and leukopenia-inducing activity in rabbits, body weight-decreasing toxicity in normal mice, lethal toxicity in galactosamine-sensitized mice and chicken embryos, and the preparation and provocation of the local Shwartzman reaction in rabbits. Compound 406, a synthetic counterpart of a biosynthetic precursor of lipid A molecule, showed by contrast only weak activities in all of the above assay systems except for the lethality in galactosamine-loaded mice. This finding strongly suggests that the presence of acyloxyacyl groups at the C-2' and C-3' positions of the disaccharide backbone is one of the most important determinant structures of the lipid A molecule for exhibition of strong biological activities characteristic of lipopolysaccharide and its lipid A moiety. The activities of the corresponding 4'-monophosphate (compound 504) and 1-monophosphate (505) analogs were considerably less than those of the parent molecule 506 and the reference F515 lipid A. Regarding other biological activities, not only compound 506 but also compounds 504, 505, and 406 showed definite activities, sometimes comparable to those of F515 lipid A and other reference natural products. These are the activation of Tachypleus tridentatus amoebocyte clotting enzyme cascade and human complement via the classical pathway, mitogenic and polyclonal B-cell activation of murine splenocytes, stimulation of peritoneal macrophages in a guinea pig, enhancement of migration of human blood

  17. The maltose ABC transporter: action of membrane lipids on the transporter stability, coupling and ATPase activity.

    PubMed

    Bao, Huan; Dalal, Kush; Wang, Victor; Rouiller, Isabelle; Duong, Franck

    2013-08-01

    The coupling between ATP hydrolysis and substrate transport remains a key question in the understanding of ABC-mediated transport. We show using the MalFGK2 complex reconstituted into nanodiscs, that membrane lipids participate directly to the coupling reaction by stabilizing the transporter in a low energy conformation. When surrounded by short acyl chain phospholipids, the transporter is unstable and hydrolyzes large amounts of ATP without inducing maltose. The presence of long acyl chain phospholipids stabilizes the conformational dynamics of the transporter, reduces its ATPase activity and restores dependence on maltose. Membrane lipids therefore play an essential allosteric function, they restrict the transporter ATPase activity to increase coupling to the substrate. In support to the notion, we show that increasing the conformational dynamics of MalFGK2 with mutations in MalF increases the transporter ATPase activity but decreases the maltose transport efficiency.

  18. Augmentation of macrophage growth-stimulating activity of lipids by their peroxidation

    SciTech Connect

    Yui, S.; Yamazaki, M. )

    1990-02-15

    Previously, we reported that some kinds of lipids (cholesterol esters, triglycerides, and some negatively charged phospholipids) that are constituents of lipoproteins or cell membranes induce growth of peripheral macrophages in vitro. In this paper, we examined the effect of peroxidation of lipids on their macrophage growth-stimulating activity because lipid peroxidation is observed in many pathological states such as inflammation. When phosphatidylserine, one of the phospholipids with growth-stimulating activity, was peroxidized by UV irradiation, its macrophage growth-stimulating activity was augmented in proportion to the extent of its peroxidation. The activity of phosphatidylethanolamine was also increased by UV irradiation. On the other hand, phosphatidylcholine or highly unsaturated free fatty acids, such as arachidonic acid and eicosapentaenoic acid, did not induce macrophage growth irrespective of whether they were peroxidized. The augmented activity of UV-irradiated phosphatidylserine was not affected by the coexistence of an antioxidant, vitamin E or BHT. These results suggest that some phospholipids included in damaged cells or denatured lipoproteins which are scavenged by macrophages in vivo may induce growth of peripheral macrophages more effectively when they are peroxidized by local pathological processes.

  19. Interactive protein network of FXIII-A1 in lipid rafts of activated and non-activated platelets.

    PubMed

    Rabani, Vahideh; Montange, Damien; Davani, Siamak

    2016-09-01

    Lipid-rafts are defined as membrane microdomains enriched in cholesterol and glycosphingolipids within platelet plasma membrane. Lipid raft-mediated clot retraction requires factor XIII and other interacting proteins. The aim of this study was to investigate the proteins that interact with factor XIII in raft and non-raft domains of activated and non-activated platelet plasma membrane. By lipidomics analysis, we identified cholesterol- and sphingomyelin-enriched areas as lipid rafts. Platelets were activated by thrombin. Proteomics analysis provided an overview of the pathways in which proteins of rafts and non-rafts participated in the interaction network of FXIII-A1, a catalytic subunit of FXIII. "Platelet activation" was the principal pathway among KEGG pathways for proteins of rafts, both before and after activation. Network analysis showed four types of interactions (activation, binding, reaction, and catalysis) in raft and non-raft domains in interactive network of FXIII-A1. FXIII-A1 interactions with other proteins in raft domains and their role in homeostasis highlight the specialization of the raft domain in clot retraction via the Factor XIII protein network.

  20. Enhanced antimalarial activity by a novel artemether-lumefantrine lipid emulsion for parenteral administration.

    PubMed

    Ma, Yufan; Lu, Tingli; Zhao, Wen; Wang, Ying; Chen, Ting; Mei, Qibing; Chen, Tao

    2014-10-01

    Artemether and lumefantrine (also known as benflumetol) are difficult to formulate for parenteral administration because of their low aqueous solubility. Cremophor EL as an emulsion excipient has been shown to cause serious side effects. This study reports a method of preparation and the therapeutic efficacies of novel lipid emulsion (LE) delivery systems with artemether, lumefantrine, or artemether in combination with lumefantrine, for parenteral administration. Their physical and chemical stabilities were also evaluated. Furthermore, the in vivo antimalarial activities of the lipid emulsions developed were tested in Plasmodium berghei-infected mice. Artemether, lumefantrine, or artemether in combination with lumefantrine was encapsulated in an oil phase, and the in vivo performance was assessed by comparison with artesunate for injection. It was found that the lumefantrine lipid emulsion (LUM-LE) and artemether-lumefantrine lipid emulsion (ARM-LUM-LE-3) (1:6) began to decrease the parasitemia levels after only 3 days, and the parasitemia inhibition was 90% at doses of 0.32 and 0.27 mg/kg, respectively, with immediate antimalarial effects greater than those of the positive-control group and constant antimalarial effects over 30 days. LUM-LE and ARM-LUM-LE-3 demonstrated the best performance in terms of chemical and physical stabilities and antiplasmodial efficacy, with a mean particle size of 150 nm, and they have many favorable properties for parenteral administration, such as biocompatibility, physical stability, and ease of preparation.

  1. Essential oils as active ingredients of lipid nanocarriers for chemotherapeutic use.

    PubMed

    Severino, Patricia; Andreani, Tatiana; Chaud, Marco V; Benites, Cibelem I; Pinho, Samantha C; Souto, Eliana B

    2015-01-01

    Essential oils have increased interest as promising ingredients for novel pharmaceutical dosage forms. These oils are reported to provide synergistic effects of their active ingredients, in parallel with their biodegradable properties. In addition, essential oils may also have therapeutic effects in diabetes, inflammation, cancer and to treat microbial infections. However, there are some physicochemical properties that may limit their use as active compounds in several formulations, such as high volatility, low-appealing organoleptic properties, low bioavailability and physicochemical instability, as result of exposure to light, oxygen and high temperatures. To overcome these limitations, lipid colloidal carriers (e.g. liposomes, solid lipid nanoparticles (SLN), self nanoemulsified drug delivery systems (SNEDDS)) have been pointed out as suitable carriers to improve bioavailability, low solubility, taste, flavor and long-term storage of sensitive compounds. This paper reviews the potential beneficial effects of formulating essential oils in pharmaceutical applications using colloidal carriers as delivery systems.

  2. Two roles of thylakoid lipids in modifying the activity of herbicides which inhibit photosystem II

    SciTech Connect

    Kupatt, C.C. Jr.

    1985-01-01

    Thylakoid lipids may modify the activity of herbicides which inhibit electron transport at the Q/sub B/ protein of photosystem II in two ways: (1) lipids can act as a hydrophobic barrier to a binding site localized close to the loculus of the membrane, and (2) changes in lipid composition can reduce the ability of inhibitors to block electron transport, possibly due to a change in the conformation of the Q/sub B/ protein. The herbicide binding site was localized close to the locular side of the thylakoid membrane by determining the activity of a number of substituted phenylurea and s-triazine herbicides in inverted and non-inverted thylakoids. Quantitative structure-activity relationship analysis showed that inversion of thylakoids reduced the requirement of molecular lipophilicity deemed necessary for phenylurea activity in non-inverted membranes, whereas s-triazines exhibited no differences in the lipophilicity requirement in thylakoid membranes of either orientation. The binding affinity of /sup 14/C-diuron was reduced in bicarbonate-depleted thylakoids relative to reconstituted or control membranes, as is the case with atrazine binding. These observations support a model of the herbicide binding site containing both common and herbicide family specific binding domains. Thylakoids isolated either from detached lambs quarters (Chenopodium album L.) leaves, treated with SAN 6706, or from soybean (Glycine max L.), with norflurazon or pyrazon applied preemergence, exhibited decreased susceptibility to atrazine. The ability of lipid-modifying treatments to decrease the atrazine susceptibility of field-grown soybeans was also investigated.

  3. Enhancement of Lytic Activity by Leptin Is Independent From Lipid Rafts in Murine Primary Splenocytes.

    PubMed

    Collin, Aurore; Noacco, Audrey; Talvas, Jérémie; Caldefie-Chézet, Florence; Vasson, Marie-Paule; Farges, Marie-Chantal

    2017-01-01

    Leptin, a pleiotropic adipokine, is known as a regulator of food intake, but it is also involved in inflammation, immunity, cell proliferation, and survival. Leptin receptor is integrated inside cholesterol-rich microdomains called lipid rafts, which, if disrupted or destroyed, could lead to a perturbation of lytic mechanism. Previous studies also reported that leptin could induce membrane remodeling. In this context, we studied the effect of membrane remodeling in lytic activity modulation induced by leptin. Thus, primary mouse splenocytes were incubated with methyl-β-cyclodextrin (β-MCD), a lipid rafts disrupting agent, cholesterol, a major component of cell membranes, or ursodeoxycholic acid (UDCA), a membrane stabilizer agent for 1 h. These treatments were followed by splenocyte incubation with leptin (absence, 10 and 100 ng/ml). Unlike β-MCD or cholesterol, UDCA was able to block leptin lytic induction. This result suggests that leptin increased the lytic activity of primary spleen cells against syngenic EO771 mammary cancer cells independently from lipid rafts but may involve membrane fluidity. Furthermore, natural killer cells were shown to be involved in the splenocyte lytic activity. To our knowledge it is the first publication in primary culture that provides the link between leptin lytic modulation and membrane remodeling. J. Cell. Physiol. 232: 101-109, 2017. © 2016 Wiley Periodicals, Inc.

  4. Theaflavins attenuate hepatic lipid accumulation through activating AMPK in human HepG2 cells.

    PubMed

    Lin, Chih-Li; Huang, Hsiu-Chen; Lin, Jen-Kun

    2007-11-01

    Black tea is one of the world's most popular beverages, and its health-promoting effects have been intensively investigated. The antiobesity and hypolipidemic effects of black tea have attracted increasing interest, but the mechanisms underlying these phenomena remain unclear. In the present study, the black tea major component theaflavins were assessed for their hepatic lipid-lowering potential when administered in fatty acid overload conditions both in cell culture and in an animal experimental model. We found that theaflavins significantly reduced lipid accumulation, suppressed fatty acid synthesis, and stimulated fatty acid oxidation. Furthermore, theaflavins also inhibited acetyl-coenzyme A carboxylase activities by stimulating AMP-activated protein kinase (AMPK) through the LKB1 and reactive oxygen species pathways. These observations support the idea that AMPK is a critical component of decreased hepatic lipid accumulation by theaflavin treatments. Our results show that theaflavins are bioavailable both in vitro and in vivo and may be active in the prevention of fatty liver and obesity.

  5. Cationic solid lipid nanoparticles interfere with the activity of antioxidant enzymes in hepatocellular carcinoma cells.

    PubMed

    Doktorovová, Slavomira; Santos, Dario L; Costa, Inês; Andreani, Tatiana; Souto, Eliana B; Silva, Amélia M

    2014-08-25

    Solid lipid nanoparticles (SLN) are colloidal drug and/or gene carriers developed from solid lipids and surfactants that are considered safe. Cationic SLN, usually used for formulating poorly water-soluble drugs and for gene delivery purposes, as positively charged particles may attach to cellular surfaces and be internalized more easily than negatively charged SLN, but they can also cause damage. The main aim of this work was to test a set of cationic SLN and investigate its influence on the amount of reactive oxygen species (ROS), on antioxidant enzymes activities and on possible oxidative damage to membrane lipids in HepG2 cells. The Dichlorofluorescein assay revealed great increase in ROS presence after cell exposure to SLN. While the exposure to SLN increased the activities of superoxide dismutase and glutathione peroxidase it decreased glutathione reductase activity. Although no significant increase in thiobarbituric reactive species was found, a decrease in sulfhydryl groups was detected. These results indicate that cationic SLN caused oxidative stress in HepG2 cells, but under reported exposure conditions HepG2 cells could attenuate the stress and thus the damage to cellular components was minimal.

  6. Non-acidic activation of pain-related Acid-Sensing Ion Channel 3 by lipids.

    PubMed

    Marra, Sébastien; Ferru-Clément, Romain; Breuil, Véronique; Delaunay, Anne; Christin, Marine; Friend, Valérie; Sebille, Stéphane; Cognard, Christian; Ferreira, Thierry; Roux, Christian; Euller-Ziegler, Liana; Noel, Jacques; Lingueglia, Eric; Deval, Emmanuel

    2016-02-15

    Extracellular pH variations are seen as the principal endogenous signal that triggers activation of Acid-Sensing Ion Channels (ASICs), which are basically considered as proton sensors, and are involved in various processes associated with tissue acidification. Here, we show that human painful inflammatory exudates, displaying non-acidic pH, induce a slow constitutive activation of human ASIC3 channels. This effect is largely driven by lipids, and we identify lysophosphatidylcholine (LPC) and arachidonic acid (AA) as endogenous activators of ASIC3 in the absence of any extracellular acidification. The combination of LPC and AA evokes robust depolarizing current in DRG neurons at physiological pH 7.4, increases nociceptive C-fiber firing, and induces pain behavior in rats, effects that are all prevented by ASIC3 blockers. Lipid-induced pain is also significantly reduced in ASIC3 knockout mice. These findings open new perspectives on the roles of ASIC3 in the absence of tissue pH variation, as well as on the contribution of those channels to lipid-mediated signaling.

  7. Toxicity and Antileishmanial Activity of a New Stable Lipid Suspension of Amphotericin B

    PubMed Central

    Larabi, Malika; Yardley, Vanessa; Loiseau, Philippe M.; Appel, Martine; Legrand, Philippe; Gulik, Annette; Bories, Christian; Croft, Simon L.; Barratt, Gillian

    2003-01-01

    The aim of the present study was to evaluate the toxicity and the activity of a new lipid complex formulation of amphotericin B (AMB) (LC-AMB; dimyristoyl phosphatidylcholine, dimyristoyl phosphatidylglycerol, and AMB) that can be produced by a simple process. Like other lipid formulations, this new complex reduced both the hemolytic activity of AMB (the concentration causing 50% hemolysis of human erythrocytes, >100 μg/ml) and its toxicity toward murine peritoneal macrophages (50% inhibitory concentration, >100 μg/ml at 24 h). The in vivo toxicity of the new formulation (50% lethal dose, >200 mg/kg of body weight for CD1 mice) was similar to those of other commercial lipid formulations of AMB. The complex was the most effective formulation against the DD8 strain of Leishmania donovani. It was unable to reverse the resistance of an AMB-resistant L. donovani strain. In vivo LC-AMB was less efficient than AmBisome against L. donovani. PMID:14638481

  8. Communication: Activation energy of tension-induced pore formation in lipid membranes.

    PubMed

    Karal, Mohammad Abu Sayem; Yamazaki, Masahito

    2015-08-28

    Tension plays a vital role in pore formation in biomembranes, but the mechanism of pore formation remains unclear. We investigated the temperature dependence of the rate constant of constant tension (σ)-induced pore formation in giant unilamellar vesicles of lipid membranes using an experimental method we developed. By analyzing this result, we determined the activation energy (Ua) of tension-induced pore formation as a function of tension. A constant (U0) that does not depend on tension was found to contribute significantly to Ua. Analysis of the activation energy clearly indicated that the dependence of Ua on σ in the classical theory is correct, but that the classical theory of pore formation is not entirely correct due to the presence of U0. We can reasonably consider that U0 is a nucleation free energy to form a hydrophilic pre-pore from a hydrophobic pre-pore or a region with lower lateral lipid density. After obtaining U0, the evolution of a pre-pore follows a classical theory. Our data provide valuable information that help explain the mechanism of tension-induced pore formation in biomembranes and lipid membranes.

  9. GST activity and membrane lipid saturation prevents mesotrione-induced cellular damage in Pantoea ananatis.

    PubMed

    Prione, Lilian P; Olchanheski, Luiz R; Tullio, Leandro D; Santo, Bruno C E; Reche, Péricles M; Martins, Paula F; Carvalho, Giselle; Demiate, Ivo M; Pileggi, Sônia A V; Dourado, Manuella N; Prestes, Rosilene A; Sadowsky, Michael J; Azevedo, Ricardo A; Pileggi, Marcos

    2016-12-01

    Callisto(®), containing the active ingredient mesotrione (2-[4-methylsulfonyl-2-nitrobenzoyl]1,3-cyclohenanedione), is a selective herbicide that controls weeds in corn crops and is a potential environmental contaminant. The objective of this work was to evaluate enzymatic and structural changes in Pantoea ananatis, a strain isolated from water, in response to exposure to this herbicide. Despite degradation of mesotrione, probably due a glutathione-S-transferase (GST) pathway in Pantoea ananatis, this herbicide induced oxidative stress by increasing hydrogen peroxide production. Thiol fragments, eventually produced after mesotrione degradation, could be involved in increased GST activity. Nevertheless, there was no peroxidation damage related to this production, as malondialdehyde (MDA) synthesis, which is due to lipid peroxidation, was highest in the controls, followed by the mesotrione- and Callisto(®)-treated cultures at log growth phase. Therefore, P. ananatis can tolerate and grow in the presence of the herbicide, probably due an efficient control of oxidative stress by a polymorphic catalase system. MDA rates depend on lipid saturation due to a pattern change to a higher level of saturation. These changes are likely related to the formation of GST-mesotrione conjugates and mesotrione degradation-specific metabolites and to the presence of cytotoxic adjuvants. These features may shift lipid membrane saturation, possibly providing a protective effect to bacteria through an increase in membrane impermeability. This response system in P. ananatis provides a novel model for bacterial herbicide tolerance and adaptation in the environment.

  10. Lipids as regulators of the activity of transient receptor potential type V1 (TRPV1) channels.

    PubMed

    De Petrocellis, Luciano; Di Marzo, Vincenzo

    2005-08-19

    After 7 years from its cloning, the transient receptor potential vanilloid type-1 (TRPV1) channel remains the sole membrane receptor mediating the pharmacological effects of the hot chilli pepper pungent component, capsaicin, and of the Euphorbia toxin, resiniferatoxin. Yet, this ion channel represents one of the most complex examples of how the activity of a protein can be regulated. Among the several chemicophysical stimuli that can modulate TRPV1 permeability to cations, endogenous lipids appear to play a major role, either as allosteric effectors or as direct agonists, or both. Furthermore, the capability of some mediators, such as the endocannabinoid anandamide, or the eicosanoid precursors 12- and 5-hydroperoxy-eicosatetraenoic acids, to activate TRPV1 receptors provides a striking example of the "site-dependent" and "metabolic" functional plasticity, respectively, typical of bioactive lipids. In this article, the multi-faceted and most recently discovered aspects of TRPV1 regulation are reviewed, with particular emphasis on the interaction between these membrane channels and some lipid molecules.

  11. Lipid lowering activity of hydrosoluble chitosan and association with Aloe vera L. and Brassica olearaceae L.

    PubMed

    Geremias, R; Pedrosa, R C; Locatelli, C; de Fávere, V T; Coury-Pedrosa, R; Laranjeira, M C M

    2006-04-01

    The lipid lowering activity of chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. has been studied in rats. In this study, rats were submitted to different treatments with hydrosoluble chitosan alone (4% diet), hydrosoluble chitosan associated with Aloe vera L. or hydrosoluble chitosan with Brassica olearaceae L. (1:4, 4% diet) for 35 days, to identify the formula with the highest hypolipaemic potential. The results showed that all treatments reduced blood lipid levels but that hydrosoluble chitosan associated with Brassica olearaceae L. proved most efficient, because it decreased the levels of total cholesterol, LDL-cholesterol, VLDL-cholesterol and triglycerides in blood serum. The overall results suggest that the hydrosoluble chitosan/Brassica olearaceae L. association is a therapeutic alternative for hyperlipidaemia, and in this way may contribute to the prevention of atherogenic processes.

  12. In vivo effects of nickel and cadmium in rats on lipid peroxidation and ceruloplasmin activity

    SciTech Connect

    Sole, J.; Huguet, J.; Arola, L.; Romeu, A. )

    1990-05-01

    Before Ni(II) and Cd(II), or any other metallic ion, can interact intracellulary, it must penetrate the cell membrane. The latter, therefore, is a primary target for toxic metals. Damage to cell membranes may allow a greater uptake of metal and thus injury may extend to more critical targets, although loss of plasmatic membrane functionality may be a crucial factor to explain the interactions of these metals with cellular components. In this sense the present study has been carried out. Factors that have been investigated in order to prove the membrane response of nickel and cadmium toxicity include lipid peroxidation, since divalent ions of transition metals can promote lipid peroxidation and this evidently contributes to the toxicity of certain metals and to metal interaction with ceruloplasmin, as its ferroxidase and scavenger of superoxide radicals activities are important protective mechanisms in vivo against peroxidative damage.

  13. Investigation of nano lipid vesicles of methotrexate for anti-rheumatoid activity

    PubMed Central

    Prabhu, Prabhakara; Shetty, Rakshith; Koland, Marina; Vijayanarayana, K; Vijayalakshmi, KK; Nairy, M Harish; Nisha, GS

    2012-01-01

    Background The purpose of this study was to formulate and evaluate nano lipid vesicles of methotrexate (MTX) for its anti-rheumatoid activity. Methods In this study the principle of both active as well as passive targeting using MTX-loaded stealth liposomes as per the magic gun approach was followed. Stealth liposomes of MTX were prepared by thin-film hydration method using a PEGylated phospholipid-like DSPE-MPEG 2000. Similarly, conventional liposomes were prepared using phospholipids like DPPC and DSPC. Conventional liposomes were coated with a hydrophilic biocompatible polymer like chitosan. They were investigated for their physical properties and in vitro release profile. Further, in vivo screening of the formulations for their anti-rheumatoid efficacy was carried out in rats. Rheumatoid arthritis was induced in male Wistar-Lewis rats using complete Freund’s adjuvant (1 mg/mL Mycobacterium tuberculosis, heat killed in mineral oil). Results It was found that chitosan coating of the conventional liposomes increased the physical stability of the liposomal suspension as well as its entrapment efficiency. The size of the unsonicated lipid vesicles was found to be in the range of 8–10 μm, and the sonicated lipid vesicles in the range of 210–260 nm, with good polydispersity index. Further, chitosan-coated conventional liposomes and the PEGylated liposomes released the drug for a prolonged period of time, compared to the uncoated conventional liposomes. It was found that there was a significant reduction in edema volume in the rat group administered with the test stealth liposomal formulations and chitosan-coated conventional liposomes (PEGylated and chitosan-coated conventional) compared to that of the control and standard (administered with free MTX) group of rats. PEGylated liposomes showed almost equal efficacy as that of the chitosan-coated conventional liposomes. Conclusion Lipid nano vesicles of MTX can be administered by intravenous route, whereby the

  14. Diazepam blocks striatal lipid peroxidation and improves stereotyped activity in a rat model of acute stress.

    PubMed

    Méndez-Cuesta, Luis A; Márquez-Valadez, Berenice; Pérez-De La Cruz, Verónica; Escobar-Briones, Carolina; Galván-Arzate, Sonia; Alvarez-Ruiz, Yarummy; Maldonado, Perla D; Santana, Ricardo A; Santamaría, Abel; Carrillo-Mora, Paul

    2011-11-01

    In this work, the effect of a single dose of diazepam was tested on different markers of oxidative damage in the striatum of rats in an acute model of immobilization (restraint) stress. In addition, the locomotor activity was measured at the end of the restraint period. Immobilization was induced to animals for 24 hr, and then, lipid peroxidation, superoxide dismutase activity and content, and mitochondrial function were all estimated in striatal tissue samples. Corticosterone levels were measured in serum. Diazepam was given to rats as a pre-treatment (1 mg/kg, i.p.) 20 min. before the initiation of stress. Our results indicate that acute stress produced enhanced striatal levels of lipid peroxidation (73% above the control), decreased superoxide dismutase activity (54% below the control), reduced levels of mitochondrial function (35% below the control) and increased corticosterone serum levels (86% above the control). Pre-treatment of stressed rats with diazepam decreased the striatal lipid peroxidation levels (68% below the stress group) and improved mitochondrial function (18% above the stress group), but only mild preservation of superoxide dismutase activity was detected (17% above the stress group). In regard to the motor assessment, only the stereotyped activity was increased in the stress group with respect to control (46% above the control), and this effect was prevented by diazepam administration (30% below the stress group). The preventive actions of diazepam in this acute model of stress suggest that drugs exhibiting anxiolytic and antioxidant properties might be useful for the design of therapies against early acute phases of physic stress.

  15. The dipeptide H-Trp-Glu-OH (WE) shows agonistic activity to peroxisome proliferator-activated protein-α and reduces hepatic lipid accumulation in lipid-loaded H4IIE cells.

    PubMed

    Jia, Yaoyao; Kim, Jong-Ho; Nam, Bora; Kim, Jiyoung; Lee, Ji Hae; Hwang, Kwang-Yeon; Lee, Sung-Joon

    2014-07-01

    Dipeptides digested from dietary proteins can be directly absorbed by the intestine and delivered to the circulatory system. However, the dipeptides' metabolic roles and biological activities are largely unknown. Lipid-loaded HII4E cells stimulated with H-Trp-Glu-OH (WE) exhibited reduced lipid accumulation, of which the effect was abolished by peroxisome proliferator-activated receptor (PPAR) α gene knock down. A luciferase assay showed that the WE dipeptide induced PPARα transactivation in a dose-dependent manner. Surface plasmon resonance and time-resolved fluorescence resonance energy transfer analyses demonstrated that WE interacts directly with the PPARα ligand binding domain (KD, 120 μM; EC50, 83 μM). Cells stimulated with WE induced PPARα and its responsive genes and increased cellular fatty acid uptake. In conclusion, WE reduces hepatic lipid accumulation in lipid-loaded hepatocytes via the activation of PPARα by a direct interaction.

  16. Novel bio-active lipid nanocarriers for the stabilization and sustained release of sitosterol

    NASA Astrophysics Data System (ADS)

    Lacatusu, I.; Badea, N.; Stan, R.; Meghea, A.

    2012-11-01

    In this work, new stable and efficiently bio-active lipid nanocarriers (NLCs) with antioxidant properties have been developed for the transport of active ingredients in food. The novel NLCs loaded with β-sitosterol/β-sitosterol and green tea extract (GTE) and prepared by a combination of natural oils (grape seed oil, fish oil and squalene) and biological lipids with food grade surfactants, were physico-chemically examined by DLS, TEM, electrokinetic potential, DSC and HPLC and found to have main diameters less than 200 nm, a spherical morphology, excellent physical stability, an imperfect crystalline lattice and high entrapment efficiency. The novel loaded-NLCs have demonstrated the potential to develop a high blocking action of chain reactions, trapping up to 92% of the free-oxygen radicals, as compared to the native β-sitosterol (AA%=36.5). Another advantage of this study is associated with the quality of bio-active NLCs based on grape seed oil and squalene to manifest a better sitosterol—sustained release behaviour as compared to their related nanoemulsions. By coupling both in vitro results, i.e. the enhanced antioxidant activity and superior release properties, this study emphasizes the sustainability of novel bio-active nanocarriers to gain specific bio-food features for development of functional foods with a high applicability spectrum.

  17. Dietary regulation of adiponectin by direct and indirect lipid activators of nuclear hormone receptors.

    PubMed

    Rühl, R; Landrier, J F

    2016-01-01

    Adiponectin is an adipokine mainly secreted by adipocytes that presents antidiabetic, anti-inflammatory, and antiatherogenic functions. Therefore, modulation of adiponectin expression represents a promising target for prevention or treatment of several diseases including insulin resistance and type II diabetes. Pharmacological agents such as the nuclear hormone receptor synthetic agonists like peroxisome proliferator activated receptor γ agonists are of particular interest in therapeutic strategies due to their ability to increase the plasma adiponectin concentration. Nutritional approaches are also of particular interest, especially in primary prevention, since some active compounds of our diet (notably vitamins, carotenoids, or other essential nutrients) are direct or indirect lipid-activators of nuclear hormone receptors and are modifiers of adiponectin expression and secretion. The aim of the present review is to summarize current knowledge about the nutritional regulation of adiponectin by derivatives of active compounds naturally present in the diet acting as indirect or direct activators of nuclear hormone receptors.

  18. Correlation between Antioxidant Enzyme Activity, Free Iron Content and Lipid Oxidation in Four Lines of Korean Native Chicken Meat

    PubMed Central

    Kim, Hye-Kyung; Cho, Chang-Yeon; Lee, Cheol-Koo

    2016-01-01

    This study was conducted to observe the association between antioxidant enzyme activity, free iron content and lipid oxidation of Korean native chicken (KNC) meat during refrigerated storage. Four lines of KNC (Yeonsan ogye, Hyunin black, Hoengseong yakdak and Hwangbong) were raised under similar conditions. A total of 16 roosters were randomly sampled and slaughtered at the age of 12 mon. The breast and thigh meats were stored aerobically for 10 d at 4℃. Although thigh meat had higher antioxidant enzyme activity, it was more susceptible to lipid oxidation and released more iron during storage than breast meat. Aerobic refrigerated storage for 10 d significantly decreased the activity of antioxidant enzymes and increased the amount of free iron and malondialdehyde. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were negatively correlated with lipid oxidation, whereas that of catalase was not. The amount of free iron was positively associated with lipid oxidation. We concluded that chicken line did not affect strongly on antioxidant enzyme activity and lipid oxidation in breast meat of KNC. However, the thigh meat of Hwangbong and Hyunin black had higher SOD and GSH-Px activity, respectively, and lower malondialdehyde contents than that of other chickens. SOD, GSH-Px and free iron play significant roles in meat lipid oxidation during refrigerated storage. PMID:27499663

  19. Low temperature alters plasma membrane lipid composition and ATPase activity of pineapple fruit during blackheart development.

    PubMed

    Zhou, Yuchan; Pan, Xiaoping; Qu, Hongxia; Underhill, Steven J R

    2014-02-01

    Plasma membrane (PM) plays central role in triggering primary responses to chilling injury and sustaining cellular homeostasis. Characterising response of membrane lipids to low temperature can provide important information for identifying early causal factors contributing to chilling injury. To this end, PM lipid composition and ATPase activity were assessed in pineapple fruit (Ananas comosus) in relation to the effect of low temperature on the development of blackheart, a form of chilling injury. Chilling temperature at 10 °C induced blackheart development in concurrence with increase in electrolyte leakage. PM ATPase activity was decreased after 1 week at low temperature, followed by a further decrease after 2 weeks. The enzyme activity was not changed during 25 °C storage. Loss of total PM phospholipids was found during postharvest senescence, but more reduction was shown from storage at 10 °C. Phosphatidylcholine and phosphatidylethanolamine were the predominant PM phospholipid species. Low temperature increased the level of phosphatidic acid but decreased the level of phosphatidylinositol. Both phospholipid species were not changed during storage at 25 °C. Postharvest storage at both temperatures decreased the levels of C18:3 and C16:1, and increased level of C18:1. Low temperature decreased the level of C18:2 and increased the level of C14:0. Exogenous application of phosphatidic acid was found to inhibit the PM ATPase activity of pineapple fruit in vitro. Modification of membrane lipid composition and its effect on the functional property of plasma membrane at low temperature were discussed in correlation with their roles in blackheart development of pineapple fruit.

  20. Ciprofloxacin Controlled-Solid Lipid Nanoparticles: Characterization, In Vitro Release, and Antibacterial Activity Assessment

    PubMed Central

    2017-01-01

    The objective of this research was to formulate ciprofloxacin (CIP) in solid lipid nanoparticles (SLNs) in an attempt to develop a controlled drug delivery system. An ultrasonic melt-emulsification method was used for preparing CIP-loaded SLNs. Key findings included that SLNs were successfully produced with average particle sizes ranging from 165 to 320 nm and polydispersity index in the range of 0.18–0.33. High entrapment efficiency values were reported in all formulations. The atomic force scanning microscopic images showed spherical shape with the size range closer to those found by the particle size analyzer. CIP release exhibited controlled-release behavior with various lipids. Ciprofloxacin solid lipid nanoparticles formula containing stearic acid (CIPSTE) displayed the strongest burst effect and the most rapid release rate. The release data revealed a better fit to the Higuchi diffusion model. After storing the CIPSTE formula at room temperature for 120 days, no significant difference in particle size and zeta potential was found. CIP-loaded SLNs exhibited superior antibacterial activity. Incorporation of CIP into SLNs leads to controlled release and a superior antibacterial effect of CIP. PMID:28194408

  1. Purification, biochemical characterization, and antimicrobial activity of a new lipid transfer protein from Coffea canephora seeds.

    PubMed

    Bard, G C V; Zottich, U; Souza, T A M; Ribeiro, S F F; Dias, G B; Pireda, S; Da Cunha, M; Rodrigues, R; Pereira, L S; Machado, O L T; Carvalho, A O; Gomes, V M

    2016-10-24

    Coffee, an agronomical crop of great economic importance, is also among the most commonly traded commodities in worldwide markets. Antimicrobial peptides, which play a role in plant defense, have been identified and isolated particularly from seeds. We isolated and immunolocalized Cc-LTP2, a new lipid transfer protein (LTP) from Coffea canephora seeds. We report its antimicrobial activity against various phytopathogenic fungi of economic importance, and against the bacterium Xanthomonas euvesicatoria. Peptides from C. canephora seeds were initially extracted using acid buffer and subjected to ion-exchange and reverse-phase chromatographies. A purified peptide of approximately 9 kDa, which we named Cc-LTP2, was then subjected to amino acid sequencing. The analyses showed that it was similar to LTPs isolated from various plants. The tissue and subcellular localization of C. canephora LTPs indicated that they were located in cell walls and intracellular palisade parenchyma, mainly in large vacuoles. The results of immunohistochemistry and histochemistry superposed from C. canephora seed tissues showed that LTPs and lipid bodies are present in organelles, supporting the hypothesis that LTPs from seeds are involved in lipid mobilization during germination. Cc-LTP2 did inhibit the development of the phytopathogenic fungi Colletotrichum lindemuthianum, Colletotrichum gloeosporioides, Fusarium solani, Fusarium lateritium, and Colletotrichum sp, but did inhibit X. euvesicatoria. Cc-LTP2 also increased membrane permeability and induced endogenous production of reactive oxygen species in all the fungi tested.

  2. Activation of integrin α5 mediated by flow requires its translocation to membrane lipid rafts in vascular endothelial cells.

    PubMed

    Sun, Xiaoli; Fu, Yi; Gu, Mingxia; Zhang, Lu; Li, Dan; Li, Hongliang; Chien, Shu; Shyy, John Y-J; Zhu, Yi

    2016-01-19

    Local flow patterns determine the uneven distribution of atherosclerotic lesions. Membrane lipid rafts and integrins are crucial for shear stress-regulated endothelial function. In this study, we investigate the role of lipid rafts and integrin α5 in regulating the inflammatory response in endothelial cells (ECs) under atheroprone versus atheroprotective flow. Lipid raft proteins were isolated from ECs exposed to oscillatory shear stress (OS) or pulsatile shear stress, and then analyzed by quantitative proteomics. Among 396 proteins redistributed in lipid rafts, integrin α5 was the most significantly elevated in lipid rafts under OS. In addition, OS increased the level of activated integrin α5 in lipid rafts through the regulation of membrane cholesterol and fluidity. Disruption of F-actin-based cytoskeleton and knockdown of caveolin-1 prevented the OS-induced integrin α5 translocation and activation. In vivo, integrin α5 activation and EC dysfunction were observed in the atheroprone areas of low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice, and knockdown of integrin α5 markedly attenuated EC dysfunction in partially ligated carotid arteries. Consistent with these findings, mice with haploinsufficency of integrin α5 exhibited a reduction of atherosclerotic lesions in the regions under atheroprone flow. The present study has revealed an integrin- and membrane lipid raft-dependent mechanotransduction mechanism by which atheroprone flow causes endothelial dysfunction.

  3. Interfacial regulation of acid ceramidase activity. Stimulation of ceramide degradation by lysosomal lipids and sphingolipid activator proteins.

    PubMed

    Linke, T; Wilkening, G; Sadeghlar, F; Mozcall, H; Bernardo, K; Schuchman, E; Sandhoff, K

    2001-02-23

    The lysosomal degradation of ceramide is catalyzed by acid ceramidase and requires sphingolipid activator proteins (SAP) as cofactors in vivo. The aim of this study was to investigate how ceramide is hydrolyzed by acid ceramidase at the water-membrane interface in the presence of sphingolipid activator proteins in a liposomal assay system. The degradation of membrane-bound ceramide was significantly increased both in the absence and presence of SAP-D when anionic lysosomal phospholipids such as bis(monoacylglycero)phosphate, phosphatidylinositol, and dolichol phosphate were incorporated into substrate-bearing liposomes. Higher ceramide degradation rates were observed in vesicles with increased membrane curvature. Dilution assays indicated that acid ceramidase remained bound to the liposomal surface during catalysis. Not only SAP-D, but also SAP-C and SAP-A, were found to be stimulators of ceramide hydrolysis in the presence of anionic phospholipids. This finding was confirmed by cell culture studies, in which SAP-A, -C, and -D reduced the amount of ceramide storage observed in fibroblasts of a patient suffering from prosaposin deficiency. Strong protein-lipid interactions were observed for both SAP-D and acid ceramidase in surface plasmon resonance experiments. Maximum binding of SAP-D and acid ceramidase to lipid bilayers occurred at pH 4.0. Our results demonstrate that anionic, lysosomal lipids are required for efficient hydrolysis of ceramide by acid ceramidase.

  4. Ethanol Enhances TGF-β Activity by Recruiting TGF-β Receptors From Intracellular Vesicles/Lipid Rafts/Caveolae to Non-Lipid Raft Microdomains.

    PubMed

    Huang, Shuan Shian; Chen, Chun-Lin; Huang, Franklin W; Johnson, Frank E; Huang, Jung San

    2016-04-01

    Regular consumption of moderate amounts of ethanol has important health benefits on atherosclerotic cardiovascular disease (ASCVD). Overindulgence can cause many diseases, particularly alcoholic liver disease (ALD). The mechanisms by which ethanol causes both beneficial and harmful effects on human health are poorly understood. Here we demonstrate that ethanol enhances TGF-β-stimulated luciferase activity with a maximum of 0.5-1% (v/v) in Mv1Lu cells stably expressing a luciferase reporter gene containing Smad2-dependent elements. In Mv1Lu cells, 0.5% ethanol increases the level of P-Smad2, a canonical TGF-β signaling sensor, by ∼ 2-3-fold. Ethanol (0.5%) increases cell-surface expression of the type II TGF-β receptor (TβR-II) by ∼ 2-3-fold from its intracellular pool, as determined by I(125) -TGF-β-cross-linking/Western blot analysis. Sucrose density gradient ultracentrifugation and indirect immunofluorescence staining analyses reveal that ethanol (0.5% and 1%) also displaces cell-surface TβR-I and TβR-II from lipid rafts/caveolae and facilitates translocation of these receptors to non-lipid raft microdomains where canonical signaling occurs. These results suggest that ethanol enhances canonical TGF-β signaling by increasing non-lipid raft microdomain localization of the TGF-β receptors. Since TGF-β plays a protective role in ASCVD but can also cause ALD, the TGF-β enhancer activity of ethanol at low and high doses appears to be responsible for both beneficial and harmful effects. Ethanol also disrupts the location of lipid raft/caveolae of other membrane proteins (e.g., neurotransmitter, growth factor/cytokine, and G protein-coupled receptors) which utilize lipid rafts/caveolae as signaling platforms. Displacement of these membrane proteins induced by ethanol may result in a variety of pathologies in nerve, heart and other tissues.

  5. Synthesis, self-assembly, and immunological activity of α-galactose-functionalized dendron-lipid amphiphiles.

    PubMed

    Trant, John F; Jain, Namrata; Mazzuca, Delfina M; McIntosh, James T; Fan, Bo; Haeryfar, S M Mansour; Lecommandoux, Sebastien; Gillies, Elizabeth R

    2016-10-14

    Nanoassemblies presenting multivalent displays of biologically active carbohydrates are of significant interest for a wide array of biomedical applications ranging from drug delivery to immunotherapy. In this study, glycodendron-lipid hybrids were developed as a new and tunable class of dendritic amphiphiles. A modular synthesis was used to prepare dendron-lipid hybrids comprising distearylglycerol and 0 through 4th generation polyester dendrons with peripheral protected amines. Following deprotection of the amines, an isothiocyanate derivative of C-linked α-galactose (α-Gal) was conjugated to the dendron peripheries, affording amphiphiles with 1 to 16 α-Gal moieties. Self-assembly in water through a solvent exchange process resulted in vesicles for the 0 through 2(nd) generation systems and micelles for the 3(rd) and 4(th) generation systems. The critical aggregation concentrations decreased with increasing dendron generation, suggesting that the effects of increasing molar mass dominated over the effects of increasing the hydrophilic weight fraction. The binding of the assemblies to Griffonia simplicifolia Lectin I (GSL 1), a protein with specificity for α-Gal was studied by quantifying the binding of fluorescently labeled assemblies to GSL 1-coated beads. It was found that binding was enhanced for amphiphiles containing higher generation dendrons. Despite their substantial structural differences with the natural ligands for the CD1d receptor, the glycodendron-lipid hybrids were capable of stimulating invariant natural killer T (iNKT) cells, a class of innate-like T cells that recognize lipid and glycolipid antigens presented by CD1d and that are implicated in a wide range of diseases and conditions including but not limited to infectious diseases, diabetes and cancer.

  6. Enzyme activity alteration by cadmium administration to rats: the possibility of iron involvement in lipid peroxidation.

    PubMed

    Casalino, E; Sblano, C; Landriscina, C

    1997-10-15

    The specific activities of D-3-hydroxybutyrate dehydrogenase (BDH) and glutamate dehydrogenase (GDH) are reduced in the liver and kidney of rats intoxicated with 2.5 mg Cd/kg body wt and sacrificed after 24 h; conversely ketone-body concentration is strongly increased in both of these organs and blood. In the same animals a great stimulation of antioxidant enzymes glutathione reductase and glutathione peroxidase occurs. The prooxidant state induced by cadmium in liver mitochondria and microsomes is unaffected by superoxide dismutase, catalase, or mannitol, whereas it is completely blocked by vitamin E thus excluding the involvement of reactive oxygen species in this process. The mechanism by which cadmium induces lipid peroxidation has been investigated by measuring the effect of this metal on liposomes. Ninety-minute treatment of liposomes with CdCl2 does not induce any lipid peroxidation. In contrast, Fe2+ ions under the same conditions cause strong liposome peroxidation. It has also been observed that cadmium promotes a time-dependent iron release from biological membranes. When lipid peroxidation is induced by a low concentration (5 microM) of FeCl2, in place of CdCl2, the characteristics of this process and the sensitivity to the various antioxidants used are similar to those observed with Cd. From these results we conclude that the prooxidative effect of cadmium is an indirect one since it is mediated by iron. With regard to the inhibitory effect on BDH and GDH following cadmium intoxication, it does not appear to be imputable to lipid peroxidation since in vitro investigations indicate that the presence of vitamin E does not remove the inhibition at all.

  7. Equilibrium sampling of environmental pollutants in fish: comparison with lipid-normalized concentrations and homogenization effects on chemical activity.

    PubMed

    Jahnke, Annika; Mayer, Philipp; Adolfsson-Erici, Margaretha; McLachlan, Michael S

    2011-07-01

    Equilibrium sampling of organic pollutants into the silicone polydimethylsiloxane (PDMS) has recently been applied in biological tissues including fish. Pollutant concentrations in PDMS can then be multiplied with lipid/PDMS distribution coefficients (D(Lipid,PDMS) ) to obtain concentrations in fish lipids. In the present study, PDMS thin films were used for equilibrium sampling of polychlorinated biphenyls (PCBs) in intact tissue of two eels and one salmon. A classical exhaustive extraction technique to determine lipid-normalized PCB concentrations, which assigns the body burden of the chemical to the lipid fraction of the fish, was additionally applied. Lipid-based PCB concentrations obtained by equilibrium sampling were 85 to 106% (Norwegian Atlantic salmon), 108 to 128% (Baltic Sea eel), and 51 to 83% (Finnish lake eel) of those determined using total extraction. This supports the validity of the equilibrium sampling technique, while at the same time confirming that the fugacity capacity of these lipid-rich tissues for PCBs was dominated by the lipid fraction. Equilibrium sampling was also applied to homogenates of the same fish tissues. The PCB concentrations in the PDMS were 1.2 to 2.0 times higher in the homogenates (statistically significant in 18 of 21 cases, p < 0.05), indicating that homogenization increased the chemical activity of the PCBs and decreased the fugacity capacity of the tissue. This observation has implications for equilibrium sampling and partition coefficients determined using tissue homogenates.

  8. The potent antioxidant activity of the vitamin K cycle in microsomal lipid peroxidation.

    PubMed

    Vervoort, L M; Ronden, J E; Thijssen, H H

    1997-10-15

    In the vitamin K cycle, vitamin K-hydroquinone, the active cofactor for gamma-glutamylcarboxylase, is continuously regenerated. The successive pathways contain oxidation of the hydroquinone to the epoxide, followed by reduction to the quinone and reduction to the hydroquinone. Vitamin K-hydroquinone is a potent radical scavenging species (Mukai et al., J Biol Chem 267: 22277-22281, 1992). We tested the potential antioxidant activity of the vitamin K cycle in lipid peroxidation reactions (thiobarbituric acid reactive substances, TBARS) in rat liver microsomes. As prooxidant we used Fe2+/ascorbate, NADPH-Fe3+/ATP, and NADPH/CCl4. Vitamin K (< or = 50 microM) on its own did not influence the formation of TBARS. In combination with 1 mM dithiothreitol (DTT), the reductive cofactor for the microsomal enzyme vitamin K epoxide reductase, vitamin K suppressed lipid peroxidation with a concentration that blocked the maximal response by 50% (IC50) of ca. 0.2 microM. Vitamin K1 (phylloquinone) and vitamin K2 (menaquinone-4) were equally active. Warfarin (5 microM) and chloro-vitamin K (50 microM), inhibitors of vitamin K epoxide reductase and gamma-glutamylcarboxylase, respectively, were able to completely abolish the antioxidant effect. Lipid peroxidation was inversely related to the amount of vitamin K hydroquinone in the reaction. Vitamin K epoxide reductase seemed sensitive to lipid peroxidation, with half of the activity being lost within 10 min during oxidation with NADPH/CCl4. The inactivation could be attenuated by antioxidants such as vitamin E, reduced glutathione, and menadione and also by a K vitamin in combination with DTT, but not by superoxide dismutase and catalase. The results show that the vitamin K cycle could act as a potent antioxidant, that the active species in all probability is vitamin K-hydroquinone, and that the primary reaction product is the semiquinone. The results also show that the reaction product is processed in the vitamin K cycle to

  9. Hydrodynamic collective effects of active protein machines in solution and lipid bilayers

    PubMed Central

    Mikhailov, Alexander S.; Kapral, Raymond

    2015-01-01

    The cytoplasm and biomembranes in biological cells contain large numbers of proteins that cyclically change their shapes. They are molecular machines that can function as molecular motors or carry out various other tasks in the cell. Many enzymes also undergo conformational changes within their turnover cycles. We analyze the advection effects that nonthermal fluctuating hydrodynamic flows induced by active proteins have on other passive molecules in solution or membranes. We show that the diffusion constants of passive particles are enhanced substantially. Furthermore, when gradients of active proteins are present, a chemotaxis-like drift of passive particles takes place. In lipid bilayers, the effects are strongly nonlocal, so that active inclusions in the entire membrane contribute to local diffusion enhancement and the drift. All active proteins in a biological cell or in a membrane contribute to such effects and all passive particles, and the proteins themselves, will be subject to them. PMID:26124140

  10. Membrane lipid physical state and modulation of the Na+,Mg2+-ATPase activity in Acholeplasma laidlawii B.

    PubMed Central

    Silvius, J R; McElhaney, R N

    1980-01-01

    Careful analysis of the Arrhenius plot of the Na+,Mg2+-ATPase (ATP pyrophosphohydrolase, EC 3.6.1.8) activity in Acholeplasma laidlawii B membranes of varying fatty acid composition has been combined with differential thermal analysis of the membrane lipid phase transitions to evaluate the effects of membrane lipid properties on the enzyme activity. Our results indicate that the enzyme is active only in association with liquid-crystalline lipids, exhibiting a significant heat capacity of activation, delta Cp++, for the ATP hydrolytic reaction in this case. Quantitative analyses of Arrhenius plots for the enzyme activity in membranes whose lipids exhibit a gel-to-liquid-crystalline phase transition in the physiological temperature range suggest that the ATPase is inactivated when its boundary lipids undergo a phase transition that is driven by the bulk lipid phase transition but is less cooperative than the latter. Our results suggest that the familiar "biphasic linear" Arrhenius plots obtained for many membrane enzymes may in fact have a more complex shape, analysis of which can furnish useful information regarding the behavior of the enzyme molecule. Images PMID:6445554

  11. Keratinocyte differentiation and upregulation of ceramide synthesis induced by an oat lipid extract via the activation of PPAR pathways.

    PubMed

    Chon, Su-Hyoun; Tannahill, Ruth; Yao, Xiang; Southall, Michael D; Pappas, Apostolos

    2015-04-01

    Activation of peroxisome proliferator-activated receptors (PPARs) has been shown to have an important role in skin barrier function by regulating differentiation and lipid synthesis in keratinocytes. Oat (Avena sativa) has long been used as a soothing agent to relieve skin irritations, and the clinical benefits of topical oat formulations have been proven; however, the mechanistic understanding of oat's mode of action remains unknown. We investigated whether an oat lipid extract could activate PPARs and subsequently increase epidermal lipid synthesis and differentiation markers. Primary human epidermal keratinocytes and transformed cell lines were treated with PPAR agonists and oat lipid extracts to investigate the PPAR agonism. PPAR target genes and epidermal differentiation markers were analysed using quantitative real-time PCR and HPTLC analysis. Oat lipid extract demonstrated robust dual agonism for PPARα and PPARβ/δ, and increased direct PPAR target gene induction in primary human keratinocytes. In addition, oat oil treatment increased both receptor expression and, consistent with the literature on PPARs, oat oil treatment resulted in a significant upregulation of differentiation genes (involucrin, SPRRs and transglutaminase 1) and ceramide processing genes (β-glucocerebrosidase, sphingomyelinases 3 and ABCA12). Further, oat oil treatment in keratinocytes significantly increased ceramide levels (70%), suggesting a functional translation of PPAR activation by oat oil in keratinocytes. Taken together, these results demonstrate that oat lipids possess robust dual agonistic activities for PPARα and PPARβ/δ, increase their gene expression and induce differentiation and ceramide synthesis in keratinocytes, which can collectively improve skin barrier function.

  12. Metabolomic study of lipids in serum for biomarker discovery in Alzheimer's disease using direct infusion mass spectrometry.

    PubMed

    González-Domínguez, R; García-Barrera, T; Gómez-Ariza, J L

    2014-09-01

    In this study, we demonstrated the potential of direct infusion mass spectrometry for the lipidomic characterization of Alzheimer's disease. Serum samples were extracted for lipids recovery, and directly analyzed using an electrospray source. Metabolomic fingerprints were subjected to multivariate analysis in order to discriminate between groups of patients and healthy controls, and then some key-compounds were identified as possible markers of Alzheimer's disease. Major differences were found in lipids, although some low molecular weight metabolites also showed significant changes. Thus, important metabolic pathways involved in neurodegeneration could be studied on the basis of these perturbations, such as membrane breakdown (phospholipids and diacylglycerols), oxidative stress (prostaglandins, imidazole and histidine), alterations in neurotransmission systems (oleamide and putrescine) and hyperammonaemia (guanidine and arginine). Moreover, it is noteworthy that some of these potential biomarkers have not been previously described for Alzheimer's disease.

  13. Synthesis and structure-activity relationships of novel cationic lipids with anti-inflammatory and antimicrobial activities.

    PubMed

    Myint, Melissa; Bucki, Robert; Janmey, Paul A; Diamond, Scott L

    2015-07-15

    Certain membrane-active cationic steroids are known to also possess both anti-inflammatory and antimicrobial properties. This combined functionality is particularly relevant for potential therapies of infections associated with elevated tissue damage, for example, cystic fibrosis airway disease, a condition characterized by chronic bacterial infections and ongoing inflammation. In this study, six novel cationic glucocorticoids were synthesized using beclomethasone, budesonide, and flumethasone. Products were either monosubstituted or disubstituted, containing one or two steroidal groups, respectively. In vitro evaluation of biological activities demonstrated dual anti-inflammatory and antimicrobial properties with limited cytotoxicity for all synthesized compounds. Budesonide-derived compounds showed the highest degree of both glucocorticoid and antimicrobial properties within their respective mono- and disubstituted categories. Structure-activity analyses revealed that activity was generally related to the potency of the parent glucocorticoid. Taken together, these data indicate that these types of dual acting cationic lipids can be synthesized with the appropriate starting steroid to tailor activities as desired.

  14. The lipid sensor GPR120 promotes brown fat activation and FGF21 release from adipocytes

    PubMed Central

    Quesada-López, Tania; Cereijo, Rubén; Turatsinze, Jean-Valery; Planavila, Anna; Cairó, Montserrat; Gavaldà-Navarro, Aleix; Peyrou, Marion; Moure, Ricardo; Iglesias, Roser; Giralt, Marta; Eizirik, Decio L.; Villarroya, Francesc

    2016-01-01

    The thermogenic activity of brown adipose tissue (BAT) and browning of white adipose tissue are important components of energy expenditure. Here we show that GPR120, a receptor for polyunsaturated fatty acids, promotes brown fat activation. Using RNA-seq to analyse mouse BAT transcriptome, we find that the gene encoding GPR120 is induced by thermogenic activation. We further show that GPR120 activation induces BAT activity and promotes the browning of white fat in mice, whereas GRP120-null mice show impaired cold-induced browning. Omega-3 polyunsaturated fatty acids induce brown and beige adipocyte differentiation and thermogenic activation, and these effects require GPR120. GPR120 activation induces the release of fibroblast growth factor-21 (FGF21) by brown and beige adipocytes, and increases blood FGF21 levels. The effects of GPR120 activation on BAT activation and browning are impaired in FGF21-null mice and cells. Thus, the lipid sensor GPR120 activates brown fat via a mechanism that involves induction of FGF21. PMID:27853148

  15. Lack of Maf1 enhances pyruvate kinase activity and fermentative metabolism while influencing lipid homeostasis in Saccharomyces cerevisiae.

    PubMed

    Mierzejewska, Jolanta; Chreptowicz, Karolina

    2016-01-01

    The Maf1 protein is a general negative repressor of RNA polymerase III, which is conserved in eukaryotes from yeast to humans. Herein, we show the yeast maf1Δ mutant increases pyruvate kinase activity, the key enzyme in glycolysis and an important player in switching between fermentative and oxidative metabolism. We observed enhanced ethanol production and elevated lipid content in the maf1Δ strain grown on glucose. However, after shifting to a non-fermentable carbon source, the opposite effect was observed, and the mutant cells accumulated smaller lipid droplets. Thus, it has been concluded that the Maf1 protein is essential for regulation of glucose metabolism and lipid homeostasis.

  16. Lipolytic activity of ricin from Ricinus sanguineus and Ricinus communis on neutral lipids.

    PubMed Central

    Lombard, S; Helmy, M E; Piéroni, G

    2001-01-01

    The present study was carried out with a view of determining ricin lipolytic activity on neutral lipids in emulsion and in a membrane-like model. Using 2,3-dimercapto-1-propanol tributyrate (BAL-TC(4)) as substrate, the lipolytic activity of ricin was found to be proportional to ricin and substrate concentrations, with an apparent K(m) (K(m,app)) of 2.4 mM, a k(cat) of 200 min(-1) and a specific activity of 1.0 unit/mg of protein. This work was extended to p-nitrophenyl (pNP) fatty acid esters containing two to twelve carbon atoms. Maximum lipolytic activity was registered on pNP decanoate (pNPC(10)), with a K(m,app) of 3.5 mM, a k(cat) of 173 min(-1) and a specific activity of 3.5 units/mg of protein. Ricin lipolytic activity is pH and galactose dependent, with a maximum at pH 7.0 in the presence of 0.2 M galactose. Using the monolayer technique with dicaprin as substrate, ricin showed a lipolytic activity proportional to the ricin concentration at 20 mN/m, which is dependent on the surface pressure of the lipid monolayer and is detectable up to 30 mN/m, a surface pressure that is of the same order of magnitude as that of natural cell membranes. The methods based on pNPC(10) and BAL-TC(4) hydrolysis are simple and reproducible; thus they can be used for routine studies of ricin lipolytic activity. Ricin from Ricinus communis and R. sanguineus were treated with diethyl p-nitrophenylphosphate, an irreversible serine esterase inhibitor, and their lipolytic activities on BAL-TC(4) and pNPC(10), and cytotoxic activity, were concurrently recorded. A reduction in lipolytic activity was accompanied by a decrease in cytotoxicity on Caco2 cells. These data support the idea that the lipolytic activity associated with ricin is relevant to a lipase whose activity is pH and galactose dependent, sensitive to diethyl p-nitrophenylphosphate, and that a lipolytic step may be involved in the process of cell poisoning by ricin. Both colorimetric tests used in this study are sensitive

  17. Human serum activates CIDEB-mediated lipid droplet enlargement in hepatoma cells

    SciTech Connect

    Singaravelu, Ragunath; Lyn, Rodney K.; Srinivasan, Prashanth; Delcorde, Julie; Steenbergen, Rineke H.; Tyrrell, D. Lorne; Pezacki, John P.

    2013-11-15

    Highlights: •Human serum induced differentiation of hepatoma cells increases cellular lipid droplet (LD) size. •The observed increase in LD size correlates with increased PGC-1α and CIDEB expression. •Induction of CIDEB expression correlates with rescue of VLDL secretion and loss of ADRP. •siRNA knockdown of CIDEB impairs the human serum mediated increase in LD size. •This system represents a cost-efficient model to study CIDEB’s role in lipid biology. -- Abstract: Human hepatocytes constitutively express the lipid droplet (LD) associated protein cell death-inducing DFFA-like effector B (CIDEB). CIDEB mediates LD fusion, as well as very-low-density lipoprotein (VLDL) maturation. However, there are limited cell culture models readily available to study CIDEB’s role in these biological processes, as hepatoma cell lines express negligible levels of CIDEB. Recent work has highlighted the ability of human serum to differentiate hepatoma cells. Herein, we demonstrate that culturing Huh7.5 cells in media supplemented with human serum activates CIDEB expression. This activation occurs through the induced expression of PGC-1α, a positive transcriptional regulator of CIDEB. Coherent anti-Stokes Raman scattering (CARS) microscopy revealed a correlation between CIDEB levels and LD size in human serum treated Huh7.5 cells. Human serum treatment also resulted in a rapid decrease in the levels of adipose differentiation-related protein (ADRP). Furthermore, individual overexpression of CIDEB was sufficient to down-regulate ADRP protein levels. siRNA knockdown of CIDEB revealed that the human serum mediated increase in LD size was CIDEB-dependent. Overall, our work highlights CIDEB’s role in LD fusion, and presents a new model system to study the PGC-1α/CIDEB pathway’s role in LD dynamics and the VLDL pathway.

  18. Lipid peroxidation inhibition and antiradical activities of some leaf fractions of Mangifera indica.

    PubMed

    Badmus, Jelili A; Adedosu, Temitope O; Fatoki, John O; Adegbite, Victor A; Adaramoye, Oluwatosin A; Odunola, Oyeronke A

    2011-01-01

    This study was undertaken to assess in vitro lipid peroxidation inhibitions and anti-radical activities of methanolic, chloroform, ethyl acetate and water fractions of Mangifera indica leaf. Inhibition of Fe(2+)-induced lipid peroxidation (LPO) in egg, brain, and liver homogenates, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (OH-) radical scavenging activities were evaluated. Total phenol was assessed in all fractions, and the reducing power of methanolic fraction was compared to gallic acid and ascorbic acid. The results showed that Fe2+ induced significant lipid peroxidation (LPO) in all the homogenates. Ethyl acetate fraction showed the highest percentage inhibition of LPO in both egg yolk (68.3%) and brain (66.3%), while the aqueous fraction exerted the highest inhibition in liver homogenate (89.1%) at a concentration of 10 microg/mL. These observed inhibitions of LPO by these fractions were higher than that of ascorbic acid used as a standard. The DPPH radical scavenging ability exhibited by ethyl acetate fraction was found to be the highest with IC50 value of 1.5 microg/mL. The ethyl acetate and methanolic fractions had the highest OH- radical scavenging ability with the same IC50 value of 5 microg/mL. The total phenol content of ethyl acetate fraction was the highest with 0.127 microg/mg gallic acid equivalent (GAE). The reductive potential of methanolic fraction showed a concentration-dependent increase. This study showed that inhibition of LPO and the DPPH and OH- radicals scavenging abilities of Mangifera indica leaf could be related to the presence of phenolic compounds. Therefore, the ethyl acetate fraction of the leaf may be a good source of natural antioxidative agent.

  19. Conserved valproic-acid-induced lipid droplet formation in Dictyostelium and human hepatocytes identifies structurally active compounds.

    PubMed

    Elphick, Lucy M; Pawolleck, Nadine; Guschina, Irina A; Chaieb, Leila; Eikel, Daniel; Nau, Heinz; Harwood, John L; Plant, Nick J; Williams, Robin S B

    2012-03-01

    Lipid droplet formation and subsequent steatosis (the abnormal retention of lipids within a cell) has been reported to contribute to hepatotoxicity and is an adverse effect of many pharmacological agents including the antiepileptic drug valproic acid (VPA). In this study, we have developed a simple model system (Dictyostelium discoideum) to investigate the effects of VPA and related compounds in lipid droplet formation. In mammalian hepatocytes, VPA increases lipid droplet accumulation over a 24-hour period, giving rise to liver cell damage, and we show a similar effect in Dictyostelium following 30 minutes of VPA treatment. Using (3)H-labelled polyunsaturated (arachidonic) or saturated (palmitic) fatty acids, we shown that VPA treatment of Dictyostelium gives rise to an increased accumulation of both types of fatty acids in phosphatidylcholine, phosphatidylethanolamine and non-polar lipids in this time period, with a similar trend observed in human hepatocytes (Huh7 cells) labelled with [(3)H]arachidonic acid. In addition, pharmacological inhibition of β-oxidation in Dictyostelium phenocopies fatty acid accumulation, in agreement with data reported in mammalian systems. Using Dictyostelium, we then screened a range of VPA-related compounds to identify those with high and low lipid-accumulation potential, and validated these activities for effects on lipid droplet formation by using human hepatocytes. Structure-activity relationships for these VPA-related compounds suggest that lipid accumulation is independent of VPA-catalysed teratogenicity and inositol depletion. These results suggest that Dictyostelium could provide both a novel model system for the analysis of lipid droplet formation in human hepatocytes and a rapid method for identifying VPA-related compounds that show liver toxicology.

  20. Bid, a Widely Expressed Proapoptotic Protein of the Bcl-2 Family, Displays Lipid Transfer Activity

    PubMed Central

    Esposti, Mauro Degli; Erler, Janine T.; Hickman, John A.; Dive, Caroline

    2001-01-01

    Bid is an abundant proapoptotic protein of the Bcl-2 family that is crucial for the induction of death receptor-mediated apoptosis in primary tissues such as liver. Bid action has been proposed to involve the relocation of its truncated form, tBid, to mitochondria to facilitate the release of apoptogenic cytochrome c. The mechanism of Bid relocation to mitochondria was unclear. We report here novel biochemical evidence indicating that Bid has lipid transfer activity between mitochondria and other intracellular membranes, thereby explaining its dynamic relocation to mitochondria. First, physiological concentrations of phospholipids such as phosphatidic acid and phosphatidylgycerol induced an accumulation of full-length Bid in mitochondria when incubated with light membranes enriched in endoplasmic reticulum. Secondly, native and recombinant Bid, as well as tBid, displayed lipid transfer activity under the same conditions and at the same nanomolar concentrations leading to mitochondrial relocation and release of cytochrome c. Thus, Bid is likely to be involved in the transport and recycling of mitochondrial phospholipids. We discuss how this new role of Bid may relate to its proapoptotic action. PMID:11585909

  1. Relationship between Active Oxygen Species, Lipid Peroxidation, Necrosis, and Phytoalexin Production Induced by Elicitins in Nicotiana.

    PubMed Central

    Rusterucci, C.; Stallaert, V.; Milat, M. L.; Pugin, A.; Ricci, P.; Blein, J. P.

    1996-01-01

    Excised leaves of Nicotiana tabacum var Xanthi and Nicotiana rustica were treated with cryptogein and capsicein, basic and acidic elicitins, respectively. Both compounds induced leaf necrosis, the intensity of which depended on concentration and duration of treatment. N. tabacum var Xanthi was the most sensitive species and cryptogein was the most active elicitin. Lipid peroxidation in elicitin-treated Nicotiana leaves was closely correlated with the appearance of necrosis. Elicitin treatments induced a rapid and transient burst of active oxygen species (AOS) in cell cultures of both Nicotiana species, with the production by Xanthi cells being 6-fold greater than that by N. rustica. Similar maximum AOS production levels were observed with both elicitins, but capsicein required 10-fold higher concentrations than those of cryptogein. Phytoalexin production was lower in response to both elicitins in N. tabacum var Xanthi cells than in N. rustica cells, and capsicein was the most efficient elicitor of this response. In cryptogein-treated cell suspensions, phytoalexin synthesis was unaffected by diphenyleneiodonium, which inhibited AOS generation, nor was it affected by tiron or catalase, which suppressed AOS accumulation in the extracellular medium. These results suggest that AOS production, lipid peroxidation, and necrosis are directly related, whereas phytoalexin production depends on neither the presence nor the intensity of these responses. PMID:12226334

  2. Influence of membrane lipid composition on flavonoid-membrane interactions: Implications on their biological activity.

    PubMed

    Selvaraj, Stalin; Krishnaswamy, Sridharan; Devashya, Venkappayya; Sethuraman, Swaminathan; Krishnan, Uma Maheswari

    2015-04-01

    The membrane interactions and localization of flavonoids play a vital role in altering membrane-mediated cell signaling cascades as well as influence the pharmacological activities such as anti-tumour, anti-microbial and anti-oxidant properties of flavonoids. Various techniques have been used to investigate the membrane interaction of flavonoids. These include partition coefficient, fluorescence anisotropy, differential scanning calorimetry, NMR spectroscopy, electrophysiological methods and molecular dynamics simulations. Each technique will provide specific information about either alteration of membrane fluidity or localization of flavonoids within the lipid bilayer. Apart from the diverse techniques employed, the concentrations of flavonoids and lipid membrane composition employed in various studies reported in literature also are different and together these variables contribute to diverse findings that sometimes contradict each other. This review highlights different techniques employed to investigate the membrane interaction of flavonoids with special emphasis on erythrocyte model membrane systems and their significance in understanding the nature and extent of flavonoid-membrane interactions. We also attempt to correlate the membrane localization and alteration in membrane fluidity with the biological activities of flavonoids such as anti-oxidant, anti-cancer and anti-microbial properties.

  3. Identification and antifungal activity of novel organic compounds found in cuticular and internal lipids of medically important flies.

    PubMed

    Gołębiowski, Marek; Cerkowniak, Magdalena; Urbanek, Aleksandra; Dawgul, Małgorzata; Kamysz, Wojciech; Boguś, Mieczysława I; Stepnowski, Piotr

    2015-01-01

    Novel organic compounds found in the cuticular and internal lipids of medically important flies were identified. Uracil, 9-tricosene, 1-oleoyl glycerol, dimethyl suberate and butyl stearate were tested for their potential antifungal activity. Minimal inhibitory concentrations of the compounds against reference strains of fungi were determined. Uracil and dimethyl suberate slightly inhibited the growth of entomopathogenic fungi. The cuticular and internal lipids of Calliphora vicina, Calliphora vomitoria, Sarcophaga carnaria and Musca domestica were studied by gas chromatography (GC) combined with mass spectrometry (GC/MS). A comparison of the lipid extracts between the preimaginal and mature stages showed adults flies contained a higher total content of the identified components. Furthermore, their amounts distinctly predominated in the internal lipids of all the species. The amount of 9-tricosene was the highest in adults of C. vicina, while the larvae and pupae had a definitively lower amount of this compound. Uracil was found to be the most abundant component in extracts obtained from C. vomitoria especially in the internal lipids of adults. 1-oleoyl glycerol was detected in all of the examined species of flies. It was most abundant in the internal extracts isolated from the larvae of C. vicina and the pupae of C. vomitoria. Suberic acid dimethyl ester was found in the larval and pupal internal lipids of C. vicina and S. carnaria in low amounts. Butyl stearate was identified only in the internal lipids of the larvae and adults of houseflies.

  4. Mimetics of caloric restriction include agonists of lipid-activated nuclear receptors.

    PubMed

    Corton, J Christopher; Apte, Udayan; Anderson, Steven P; Limaye, Pallavi; Yoon, Lawrence; Latendresse, John; Dunn, Corrie; Everitt, Jeffrey I; Voss, Kenneth A; Swanson, Cynthia; Kimbrough, Carie; Wong, Jean S; Gill, Sarjeet S; Chandraratna, Roshantha A S; Kwak, Mi-Kyoung; Kensler, Thomas W; Stulnig, Thomas M; Steffensen, Knut R; Gustafsson, Jan-Ake; Mehendale, Harihara M

    2004-10-29

    The obesity epidemic in industrialized countries is associated with increases in cardiovascular disease (CVD) and certain types of cancer. In animal models, caloric restriction (CR) suppresses these diseases as well as chemical-induced tissue damage. These beneficial effects of CR overlap with those altered by agonists of nuclear receptors (NR) under control of the fasting-responsive transcriptional co-activator, peroxisome proliferator-activated co-activator 1alpha (PGC-1alpha). In a screen for compounds that mimic CR effects in the liver, we found statistically significant overlaps between the CR transcript profile in wild-type mice and the profiles altered by agonists of lipid-activated NR, including peroxisome proliferator-activated receptor alpha (PPARalpha), liver X receptor, and their obligate heterodimer partner, retinoid X receptor. The overlapping genes included those involved in CVD (lipid metabolism and inflammation) and cancer (cell fate). Based on this overlap, we hypothesized that some effects of CR are mediated by PPARalpha. As determined by transcript profiling, 19% of all gene expression changes in wild-type mice were dependent on PPARalpha, including Cyp4a10 and Cyp4a14, involved in fatty acid omega-oxidation, acute phase response genes, and epidermal growth factor receptor but not increases in PGC-1alpha. CR protected the livers of wild-type mice from damage induced by thioacetamide, a liver toxicant and hepatocarcinogen. CR protection was lost in PPARalpha-null mice due to inadequate tissue repair. These results demonstrate that PPARalpha mediates some of the effects of CR and indicate that a pharmacological approach to mimicking many of the beneficial effects of CR may be possible.

  5. Fatty acid composition of plasma lipids and erythrocyte membranes during simulated extravehicular activity

    NASA Astrophysics Data System (ADS)

    Skedina, M. A.; Katuntsev, V. P.; Buravkova, L. B.; Naidina, V. P.

    Ten subjects (from 27 to 41 years) have been participated in 32 experiments. They were decompressed from ground level to 40-35 kPa in altitude chamber when breathed 100% oxygen by mask and performed repeated cycles of exercises (3.0 Kcal/min). The intervals between decompressions were 3-5 days. Plasma lipid and erythrocyte membrane fatty acid composition was evaluated in the fasting venous blood before and immediately after hypobaric exposure. There were 7 cases decompression sickness (DCS). Venous gas bubbles (GB) were detected in 27 cases (84.4%). Any significant changes in the fatty acid composition of erythrocyte membranes and plasma didn't practically induce after the first decompression. However, by the beginning of the second decompression the total lipid level in erythrocyte membranes decreased from 54.6 mg% to 40.4 mg% in group with DCS symptoms and from 51.2 mg% to 35.2 mg% (p < 0.05) without DCS symptoms. In group with DCS symptoms a tendency to increased level of saturated fatty acids in erythrocyte membranes (16:0, 18:0), the level of the polyunsaturated linoleic fatty acid (18:2) and arachidonic acid (20:4) tended to be decreased by the beginning of the second decompression. Insignificant changes in blood plasma fatty acid composition was observed in both groups. The obtained biochemical data that indicated the simulated extravehicular activity (EVA) condition is accompanied by the certain changes in the blood lipid metabolism, structural and functional state of erythrocyte membranes, which are reversible. The most pronounced changes are found in subjects with DCS symptoms.

  6. Structural stability and surface activity of sunflower 2S albumins and nonspecific lipid transfer protein.

    PubMed

    Berecz, Bernadett; Mills, E N Clare; Tamás, László; Láng, Ferenc; Shewry, Peter R; Mackie, Alan R

    2010-05-26

    The structural and interfacial properties of five different fractions of sunflower ( Helianthus annuus L.) seed storage proteins were studied. The fractions comprised lipid transfer protein (LTP), the methionine-rich 2S albumin SFA8 (sunflower albumin 8), and three mixtures of non-methionine-rich 2S albumins called Alb1 and Alb2 proteins (sunflower albumins 1 and 2). Heating affected all of the proteins studied, with SFA8 and LTP becoming more surface active than the native proteins after heating and cooling. LTP appeared to be less thermostable than homologous LTPs from other plant species. SFA8 generated the greatest elastic modulus and formed the most stable emulsions, whereas LTP showed poorer emulsification properties. The mixed 2S albumin fractions showed moderate levels of surface activity but had the poorest emulsification properties among the proteins studied.

  7. Inhibition of iron induced lipid peroxidation and antioxidant activity of Indian spices and Acacia in vitro.

    PubMed

    Yadav, Amit Singh; Bhatnagar, Deepak

    2010-03-01

    The spices used in the Indian foods such as Star anise (Illicium verum), Bay leaves (Cinnamomum zeylanicum) and Cobra's saffron (Mesua ferrea), and Acacia (Acacia catechu), which have medicinal value, were used as test samples, to find their effect on in vitro lipid peroxidation (LPO). Rat liver post mitochondrial supernatant (PMS) in Tris HCl buffer, pH 7.4 was incubated for 0 and 1 h, with various test extracts in three different oxidant systems. The results show that addition of test samples to FeCl(3) medium at 0 h significantly stop the initiation of the LPO. However, the propagation phase of LPO was inhibited by Cobra's saffron and Acacia and not by Star anise and Bay leaves. The test samples also showed strong reducing power and superoxide radical scavenging activity. Cobra's saffron and Acacia showed the highest antioxidant activity, probably due to the higher polyphenol content as compared to other test samples.

  8. AMPK activation promotes lipid droplet dispersion on detyrosinated microtubules to increase mitochondrial fatty acid oxidation

    PubMed Central

    Herms, Albert; Bosch, Marta; Reddy, Babu J.N.; Schieber, Nicole L.; Fajardo, Alba; Rupérez, Celia; Fernández-Vidal, Andrea; Ferguson, Charles; Rentero, Carles; Tebar, Francesc; Enrich, Carlos; Parton, Robert G.; Gross, Steven P.; Pol, Albert

    2015-01-01

    Lipid droplets (LDs) are intracellular organelles that provide fatty acids (FAs) to cellular processes including synthesis of membranes and production of metabolic energy. While known to move bidirectionally along microtubules (MTs), the role of LD motion and whether it facilitates interaction with other organelles are unclear. Here we show that during nutrient starvation, LDs and mitochondria relocate on detyrosinated MT from the cell centre to adopt a dispersed distribution. In the cell periphery, LD–mitochondria interactions increase and LDs efficiently supply FAs for mitochondrial beta-oxidation. This cellular adaptation requires the activation of the energy sensor AMPK, which in response to starvation simultaneously increases LD motion, reorganizes the network of detyrosinated MTs and activates mitochondria. In conclusion, we describe the existence of a specialized cellular network connecting the cellular energetic status and MT dynamics to coordinate the functioning of LDs and mitochondria during nutrient scarcity. PMID:26013497

  9. Stearoyl CoA desaturase is required to produce active, lipid-modified Wnt proteins.

    PubMed

    Rios-Esteves, Jessica; Resh, Marilyn D

    2013-09-26

    Wnt proteins contain palmitoleic acid, an unusual lipid modification. Production of an active Wnt signal requires the acyltransferase Porcupine and depends on the attachment of palmitoleic acid to Wnt. The source of this monounsaturated fatty acid has not been identified, and it is not known how Porcupine recognizes its substrate and whether desaturation occurs before or after fatty acid transfer to Wnt. Here, we show that stearoyl desaturase (SCD) generates a monounsaturated fatty acid substrate that is then transferred by Porcupine to Wnt. Treatment of cells with SCD inhibitors blocked incorporation of palmitate analogs into Wnt3a and Wnt5a and reduced Wnt secretion as well as autocrine and paracrine Wnt signaling. The SCD inhibitor effects were rescued by exogenous addition of monounsaturated fatty acids. We propose that SCD is a key molecular player responsible for Wnt biogenesis and processing and that SCD inhibition provides an alternative mechanism for blocking Wnt pathway activation.

  10. Lipid raft-regulated IGF-1R activation antagonizes TRAIL-induced apoptosis in gastric cancer cells.

    PubMed

    Xu, Ling; Qu, Xiujuan; Hu, Xuejun; Zhu, Zhitu; Li, Ce; Li, Enze; Ma, Yanju; Song, Na; Liu, Yunpeng

    2013-11-29

    Gastric cancer cells are resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and the resistance mechanism is not fully understood. In human gastric cancer MGC803 and BGC823 cells, TRAIL induces insulin-like growth factor-1 receptor (IGF-1R) pathway activation. Treatment with IGF-1R inhibitor OSI-906 or small interfering RNAs against IGF-1R, prevents IGF-1R pathway activation and increases TRAIL-induced apoptosis. The TRAIL-induced IGF-1R pathway activation is promoted by IGF-1R translocation into lipid rafts. Moreover, the translocation of IGF-1R into lipid rafts is regulated by Casitas B-lineage lymphoma b (Cbl-b). Taken together, TRAIL-induced IGF-1R activation antagonizes TRAIL-induced apoptosis by Cbl-b-regulated distribution of IGF-1R in lipid rafts.

  11. A repressor activator protein1 homologue from an oleaginous strain of Candida tropicalis increases storage lipid production in Saccharomyces cerevisiae.

    PubMed

    Chattopadhyay, Atrayee; Dey, Prabuddha; Barik, Amita; Bahadur, Ranjit P; Maiti, Mrinal K

    2015-06-01

    The repressor activator protein1 (Rap1) has been studied over the years as a multifunctional regulator in Saccharomyces cerevisiae. However, its role in storage lipid accumulation has not been investigated. This report documents the identification and isolation of a putative transcription factor CtRap1 gene from an oleaginous strain of Candida tropicalis, and establishes the direct effect of its expression on the storage lipid accumulation in S. cerevisiae, usually a non-oleaginous yeast. In silico analysis revealed that the CtRap1 polypeptide binds relatively more strongly to the promoter of fatty acid synthase1 (FAS1) gene of S. cerevisiae than ScRap1. The expression level of CtRap1 transcript in vivo was found to correlate directly with the amount of lipid produced in oleaginous native host C. tropicalis. Heterologous expression of the CtRap1 gene resulted in ∼ 4-fold enhancement of storage lipid content (57.3%) in S. cerevisiae. We also showed that the functionally active CtRap1 upregulates the endogenous ScFAS1 and ScDGAT genes of S. cerevisiae, and this, in turn, might be responsible for the increased lipid production in the transformed yeast. Our findings pave the way for the possible utility of the CtRap1 gene in suitable microorganisms to increase their storage lipid content through transcription factor engineering.

  12. In Vitro and In Vivo Trypanocidal Activity of H2bdtc-Loaded Solid Lipid Nanoparticles

    PubMed Central

    Carneiro, Zumira A.; da S. Maia, Pedro I.; Sesti-Costa, Renata; Lopes, Carla D.; Pereira, Tatiana A.; Milanezi, Cristiane M.; da Silva, Marcelo A. Pereira.; Lopez, Renata F. V.; Silva, João S.; Deflon, Victor M.

    2014-01-01

    The parasite Trypanosoma cruzi causes Chagas disease, which remains a serious public health concern and continues to victimize thousands of people, primarily in the poorest regions of Latin America. In the search for new therapeutic drugs against T. cruzi, here we have evaluated both the in vitro and the in vivo activity of 5-hydroxy-3-methyl-5-phenyl-pyrazoline-1-(S-benzyl dithiocarbazate) (H2bdtc) as a free compound or encapsulated into solid lipid nanoparticles (SLN); we compared the results with those achieved by using the currently employed drug, benznidazole. H2bdtc encapsulated into solid lipid nanoparticles (a) effectively reduced parasitemia in mice at concentrations 100 times lower than that normally employed for benznidazole (clinically applied at a concentration of 400 µmol kg−1 day−1); (b) diminished inflammation and lesions of the liver and heart; and (c) resulted in 100% survival of mice infected with T. cruzi. Therefore, H2bdtc is a potent trypanocidal agent. PMID:24810753

  13. Redistribution of Cholesterol in Model Lipid Membranes in Response to the Membrane-Active Peptide Alamethicin

    NASA Astrophysics Data System (ADS)

    Heller, William; Qian, Shuo

    2013-03-01

    The cellular membrane is a heterogeneous, dynamic mixture of molecules and macromolecules that self-assemble into a tightly-regulated functional unit that provides a semipermeable barrier between the cell and its environment. Among the many compositional differences between mammalian and bacterial cell membranes that impact its physical properties, one key difference is cholesterol content, which is more prevalent in mammals. Cholesterol is an amphiphile that associates with membranes and serves to maintain its fluidity and permeability. Membrane-active peptides, such as the alpha-helical peptide alamethicin, interact with membranes in a concentration- and composition-dependent manner to form transmembrane pores that are responsible for the lytic action of the peptide. Through the use of small-angle neutron scattering and deuterium labeling, it was possible to observe a redistribution of the lipid and cholesterol in unilamellar vesicles in response to the presence of alamethicin at a peptide-to-lipid ratio of 1/200. The results demonstrate that the membrane remodeling powers of alamethicin reach beyond the membrane thinning effect to altering the localization of specific components in the bilayer, complementing the accepted two-state mechanism of pore formation. Research was supported by U. S. DOE-OBER (CSMB; FWP ERKP291) and the U. S. DOE-BES Scientific User Facilities Division (ORNL's SNS and HFIR).

  14. Insulin Clearance Is Associated with Hepatic Lipase Activity and Lipid and Adiposity Traits in Mexican Americans

    PubMed Central

    Labadzhyan, Artak; Cui, Jinrui; Péterfy, Miklós; Guo, Xiuqing; Chen, Yii-Der I.; Hsueh, Willa A.; Rotter, Jerome I.; Goodarzi, Mark O.

    2016-01-01

    Reduction in insulin clearance plays an important role in the compensatory response to insulin resistance. Given the importance of this trait to the pathogenesis of diabetes, a deeper understanding of its regulation is warranted. Our goal was to identify metabolic and cardiovascular traits that are independently associated with metabolic clearance rate of insulin (MCRI). We conducted a cross-sectional analysis of metabolic and cardiovascular traits in 765 participants from the Mexican-American Coronary Artery Disease (MACAD) project who had undergone blood sampling, oral glucose tolerance test, euglycemic-hyperinsulinemic clamp, dual-energy X-ray absorptiometry, and carotid ultrasound. We assessed correlations of MCRI with traits from seven domains, including anthropometry, biomarkers, cardiovascular, glucose homeostasis, lipase activity, lipid profile, and liver function tests. We found inverse independent correlations between MCRI and hepatic lipase (P = 0.0004), insulin secretion (P = 0.0002), alanine aminotransferase (P = 0.0045), total fat mass (P = 0.014), and diabetes (P = 0.03). MCRI and apolipoprotein A-I exhibited a positive independent correlation (P = 0.035). These results generate a hypothesis that lipid and adiposity associated traits related to liver function may play a role in insulin clearance. PMID:27846285

  15. First isolation and antinociceptive activity of a lipid transfer protein from noni (Morinda citrifolia) seeds.

    PubMed

    Campos, Dyély C O; Costa, Andrea S; Lima, Amanda D R; Silva, Fredy D A; Lobo, Marina D P; Monteiro-Moreira, Ana Cristina O; Moreira, Renato A; Leal, Luzia K A M; Miron, Diogo; Vasconcelos, Ilka M; Oliveira, Hermógenes D

    2016-05-01

    In this study a novel heat-stable lipid transfer protein, designated McLTP1, was purified from noni (Morinda citrifolia L.) seeds, using four purification steps which resulted in a high-purified protein yield (72 mg McLTP1 from 100g of noni seeds). McLTP1 exhibited molecular masses of 9.450 and 9.466 kDa, determined by electrospray ionisation mass spectrometry. The N-terminal sequence of McLTP1 (AVPCGQVSSALSPCMSYLTGGGDDPEARCCAGV), as analysed by NCBI-BLAST database, revealed a high degree of identity with other reported plant lipid transfer proteins. In addition, this protein proved to be resistant to pepsin, trypsin and chymotrypsin digestion. McLTP1 given intraperitoneally (1, 2, 4 and 8 mg/kg) and orally (8 mg/kg) caused an inhibition of the writhing response induced by acetic acid in mice. This protein displayed thermostability, retaining 100% of its antinociceptive activity after 30 min incubation at 80 °C. Pretreatment of mice with McLTP1 (8 mg/kg, i.p. and p.o.) also decreased neurogenic and inflammatory phases of nociception in the formalin test. Naloxone (2 mg/kg, i.p.) antagonised the antinociceptive effect of McLTP1 suggesting that the opioid mechanisms mediate the analgesic properties of this protein.

  16. Antioxidant activity of idebenone-loaded neutral and cationic solid-lipid nanoparticles.

    PubMed

    Leonardi, Antonio; Crasci', Lucia; Panico, Annamaria; Pignatello, Rosario

    2015-01-01

    Idebenone (IDE) is a lipophilic benzoquinone electron carrier synthetic analogue of coenzyme Q10, which behaves as an antioxidant and free radical scavenging molecule. Recently, the therapeutic application of IDE in Leber's hereditary optic neuropathy has been discussed. This work was aimed at evaluating the encapsulation of IDE in solid-lipid nanoparticles (SLN). In particular, we tested the possibility of adapting the quasi-emulsion solvent diffusion technique, already proposed to produce polymeric nanoparticles, to prepare positively charged SLN with different compositions. Such a charge, due to the addition of a cationic lipid, would facilitate the interaction with the negatively charged eye surface epithelium, with a consequent longer pre-corneal residence time of the colloidal systems. In a preliminary evaluation of the produced IDE-loaded SLN, the antioxidant activity of the drug was demonstrated using an oxygen radical absorbance capacity assay. Encapsulation of the drug in the nanocarrier systems seems able to protect IDE from degradation and prolong its antioxidant potential.

  17. A novel peroxisome proliferator-activated receptor alpha/gamma dual agonist demonstrates favorable effects on lipid homeostasis.

    PubMed

    Guo, Qiu; Sahoo, Soumya P; Wang, Pei-Ran; Milot, Denise P; Ippolito, Marc C; Wu, Margaret S; Baffic, Joanne; Biswas, Chhabi; Hernandez, Melba; Lam, My-Hanh; Sharma, Neelam; Han, Wei; Kelly, Linda J; MacNaul, Karen L; Zhou, Gaochao; Desai, Ranjit; Heck, James V; Doebber, Thomas W; Berger, Joel P; Moller, David E; Sparrow, Carl P; Chao, Yu-Sheng; Wright, Samuel D

    2004-04-01

    Patients with type 2 diabetes mellitus exhibit hyperglycemia and dyslipidemia as well as a markedly increased incidence of atherosclerotic cardiovascular disease. Here we report the characterization of a novel arylthiazolidinedione capable of lowering both glucose and lipid levels in animal models. This compound, designated TZD18, is a potent agonist with dual human peroxisome proliferator-activated receptor (PPAR)-alpha/gamma activities. In keeping with its PPARgamma activity, TZD18 caused complete normalization of the elevated glucose in db/db mice and Zucker diabetic fatty rats. TZD18 lowered both cholesterol and triglycerides in hamsters and dogs. TZD18 inhibited cholesterol biosynthesis at steps before mevalonate and reduced hepatic levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. Moreover, TZD18 significantly suppressed gene expression of fatty acid synthesis and induced expression of genes for fatty acid degradation and triglyceride clearance. Studies on 17 additional PPARalpha or PPARalpha/gamma agonists showed that lipid lowering in hamsters correlated with the magnitude of hepatic gene expression changes. Importantly, the presence of PPARgamma agonism did not affect the relationship between hepatic gene expression and lipid lowering. Taken together, these data suggest that PPARalpha/gamma agonists, such as TZD18, affect lipid homeostasis, leading to an antiatherogenic plasma lipid profile. Agents with these properties may provide favorable means for treatment of type 2 diabetes and dyslipidemia and the prevention of atherosclerotic cardiovascular disease.

  18. Nitric oxide inhibition of adenylyl cyclase type 6 activity is dependent upon lipid rafts and caveolin signaling complexes.

    PubMed

    Ostrom, Rennolds S; Bundey, Richard A; Insel, Paul A

    2004-05-07

    Several cell types, including cardiac myocytes and vascular endothelial cells, produce nitric oxide (NO) via both constitutive and inducible isoforms of NO synthase. NO attenuates cardiac contractility and contributes to contractile dysfunction in heart failure, although the precise molecular mechanisms for these effects are poorly defined. Adenylyl cyclase (AC) isoforms type 5 and 6, which are preferentially expressed in cardiac myocytes, may be inhibited via a direct nitrosylation by NO. Because endothelial NO synthase (eNOS and NOS3), beta-adrenergic (betaAR) receptors, and AC6 all can localize in lipid raft/caveolin-rich microdomains, we sought to understand the role of lipid rafts in organizing components of betaAR-G(s)-AC signal transduction together with eNOS. Using neonatal rat cardiac myocytes, we found that disruption of lipid rafts with beta-cyclodextrin inhibited forskolin-stimulated AC activity and cAMP production, eliminated caveolin-3-eNOS interaction, and increased NO production. betaAR- and G(s)-mediated activation of AC activity were inhibited by beta-cyclodextrin treatment, but prostanoid receptor-stimulated AC activity, which appears to occur outside caveolin-rich microdomains, was unaffected unless eNOS was overexpressed and lipid rafts were disrupted. An NO donor, SNAP, inhibited basal and forskolin-stimulated cAMP production in both native cardiac myocytes and cardiac myocytes and pulmonary artery endothelial cells engineered to overexpress AC6. These effects of SNAP were independent of guanylyl cyclase activity and were mimicked by overexpression of eNOS. The juxtaposition of eNOS with betaAR and AC types 5 and 6 results in selective regulation of betaAR by eNOS activity in lipid raft domains over other G(s)-coupled receptors localized in nonraft domains. Thus co-localization of multiple signaling components in lipid rafts provides key spatial regulation of AC activity.

  19. Activation of autophagy in macrophages by pro-resolving lipid mediators

    PubMed Central

    Prieto, Patricia; Rosales-Mendoza, César Eduardo; Terrón, Verónica; Toledano, Víctor; Cuadrado, Antonio; López-Collazo, Eduardo; Bannenberg, Gerard; Martín-Sanz, Paloma; Fernández-Velasco, María; Boscá, Lisardo

    2015-01-01

    The resolution of inflammation is an active process driven by specialized pro-resolving lipid mediators, such as 15-epi-LXA4 and resolvin D1 (RvD1), that promote tissue regeneration. Macrophages regulate the innate immune response being key players during the resolution phase to avoid chronic inflammatory pathologies. Their half-life is tightly regulated to accomplish its phagocytic function, allowing the complete cleaning of the affected area. The balance between apoptosis and autophagy appears to be essential to control the survival of these immune cells within the inflammatory context. In the present work, we demonstrate that 15-epi-LXA4 and RvD1 at nanomolar concentrations promote autophagy in murine and human macrophages. Both compounds induced the MAP1LC3-I to MAP1LC3-II processing and the degradation of SQSTM1 as well as the formation of MAP1LC3+ autophagosomes, a typical signature of autophagy. Furthermore, 15-epi-LXA4 and RvD1 treatment favored the fusion of the autophagosomes with lysosomes, allowing the final processing of the autophagic vesicles. This autophagic response involves the activation of MAPK1 and NFE2L2 pathways, but by an MTOR-independent mechanism. Moreover, these pro-resolving lipids improved the phagocytic activity of macrophages via NFE2L2. Therefore, 15-epi-LXA4 and RvD1 improved both survival and functionality of macrophages, which likely supports the recovery of tissue homeostasis and avoiding chronic inflammatory diseases. PMID:26506892

  20. Activation of autophagy in macrophages by pro-resolving lipid mediators.

    PubMed

    Prieto, Patricia; Rosales-Mendoza, César Eduardo; Terrón, Verónica; Toledano, Víctor; Cuadrado, Antonio; López-Collazo, Eduardo; Bannenberg, Gerard; Martín-Sanz, Paloma; Fernández-Velasco, María; Boscá, Lisardo

    2015-01-01

    The resolution of inflammation is an active process driven by specialized pro-resolving lipid mediators, such as 15-epi-LXA4 and resolvin D1 (RvD1), that promote tissue regeneration. Macrophages regulate the innate immune response being key players during the resolution phase to avoid chronic inflammatory pathologies. Their half-life is tightly regulated to accomplish its phagocytic function, allowing the complete cleaning of the affected area. The balance between apoptosis and autophagy appears to be essential to control the survival of these immune cells within the inflammatory context. In the present work, we demonstrate that 15-epi-LXA4 and RvD1 at nanomolar concentrations promote autophagy in murine and human macrophages. Both compounds induced the MAP1LC3-I to MAP1LC3-II processing and the degradation of SQSTM1 as well as the formation of MAP1LC3(+) autophagosomes, a typical signature of autophagy. Furthermore, 15-epi-LXA4 and RvD1 treatment favored the fusion of the autophagosomes with lysosomes, allowing the final processing of the autophagic vesicles. This autophagic response involves the activation of MAPK1 and NFE2L2 pathways, but by an MTOR-independent mechanism. Moreover, these pro-resolving lipids improved the phagocytic activity of macrophages via NFE2L2. Therefore, 15-epi-LXA4 and RvD1 improved both survival and functionality of macrophages, which likely supports the recovery of tissue homeostasis and avoiding chronic inflammatory diseases.

  1. Mechanical stimulation of skeletal muscle generates lipid-related second messengers by phospholipase activation

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H. H.; Shansky, J.; Karlisch, P.; Solerssi, R. L.

    1993-01-01

    Repetitive mechanical stimulation of cultured avian skeletal muscle increases the synthesis of prostaglandins (PG) E2 and F2 alpha which regulate protein turnover rates and muscle cell growth. These stretch-induced PG increases are reduced in low extracellular calcium medium and by specific phospholipase inhibitors. Mechanical stimulation increases the breakdown rate of 3H-arachidonic acid labelled phospholipids, releasing free 3H-arachidonic acid, the rate-limiting precursor of PG synthesis. Mechanical stimulation also increases 3H-arachidonic acid labelled diacylglycerol formation and intracellular levels of inositol phosphates from myo-[2-3H]inositol labelled phospholipids. Phospholipase A2 (PLA2), phosphatidylinositol-specific phospholipase C (PLC), and phospholipase D (PLD) are all activated by stretch. The stretch-induced increases in PG production, 3H-arachidonic acid labelled phospholipid breakdown, and 3H-arachidonic acid labelled diacylglycerol formation occur independently of cellular electrical activity (tetrodotoxin insensitive) whereas the formation of inositol phosphates from myo-[2-3H]inositol labelled phospholipids is dependent on cellular electrical activity. These results indicate that mechanical stimulation increases the lipid-related second messengers arachidonic acid, diacylglycerol, and PG through activation of specific phospholipases such as PLA2 and PLD, but not by activation of phosphatidylinositol-specific PLC.

  2. Enzyme activities and membrane lipids in artemia cysts after a long duration space flight

    NASA Astrophysics Data System (ADS)

    Gaubin, Y.; Prévost, M. C.; Cariven, C.; Pianezzi, B.; Planel, H.; Soleilhavoup, J. P.

    1996-01-01

    In the Free Flyer Biostack Experiment (L.D.E.F. mission) investigations have shown that biological objects in a resting state can survive more than 5.5 years of exposure to the space factors in particular microgravity and cosmic rays. We have measured enzyme activities involved in metabolic pathways of sugar and lipid degradation and determined phospholipid composition. Pyruvate kinase and glucose-6-phosphate dehydrogenase activities in space-exposed cysts were higher than in earth controls after 1 hour incubation. In controls, total phospholipids remained unchanged, on the contrary they increased significantly in space-exposed cysts. The rate of metabolism of various phospholipid components was unchanged in controls allowing the development while the level of most of them decreased in space-exposed cysts except for phosphatidylcholine. Enzyme activities (acetylhydrolase, phospholipase A_2 and lyso phospholipase) involved in phospholipid degradation increased ; however, activities were much higher in space-exposed cysts. In conclusion, the long duration space flight resulted in an increase of the metabolic activity correlated with a faster development within the first 20 hours of post flight incubation.

  3. Mechanical stimulation of skeletal muscle generates lipid-related second messengers by phospholipase activation

    NASA Technical Reports Server (NTRS)

    Vandenburgh, Herman H.; Shansky, Janet; Karlisch, Patricia; Solerssi, Rosa Lopez

    1991-01-01

    Repetitive mechanical stimulation of cultured avian skeletal muscle increases the synthesis of prostaglandins E2 and F2(alpha) which regulate protein turnover rates and muscle cell growth. Mechnical stimulation significantly increases the breakdown rate of (3)H-arachidonic acid labelled phospholipids, releasing free (3)H-arachidonic acid, and the rate-limiting precursor of prostaglandin synthesis. Mechanical stimulation also significantly increases (3)H-arachidonic acid labelled diacylglycerol formation and intracellular levels of inositol phosphates from myo-2-(3)H inositol labelled phospholipids. Phospholipase A2, phosphatidylinositol-specific phospholipase C (PLC), and phospholipase D (PLD) are activated by stretch. The lipase inhibitors bromophenacylbromide and RHC80267 together reduce stretch-induced prostaglandin production by 73-83 percent. The stretch-induced increases in prostaglandin production, (3)H-arachidonic acid labelled phospholipid breakdown, and (3)H-arachidonic acid labelled diacylglycerol formation occur independently of cellular electrical activity (tetrodotoxin insensitive) whereas the formation of inositol phosphates from myo-2-(3)H inositol labelled phospholipids are dependent on cellular electrical activity. These results indicate that mechanical stimulation increases the lipid-related second messengers arachidonic acid, diacylglycerol, and prostaglandins through activation of specific phospholipases such as PLA2 and PLD, but not by activation of phosphatidylinositol-specific PLC.

  4. Sodium pump molecular activity and membrane lipid composition in two disparate ectotherms, and comparison with endotherms.

    PubMed

    Turner, Nigel; Hulbert, A J; Else, Paul L

    2005-02-01

    Previous research has shown that the lower sodium pump molecular activity observed in tissues of ectotherms compared to endotherms, is largely related to the lower levels of polyunsaturates and higher levels of monounsaturates found in the cell membranes of ectotherms. Marine-based ectotherms, however, have very polyunsaturated membranes, and in the current study, we measured molecular activity and membrane lipid composition in tissues of two disparate ectothermic species, the octopus (Octopus vulgaris) and the bearded dragon lizard (Pogona vitticeps), to determine whether the high level of membrane polyunsaturation generally observed in marine-based ectotherms is associated with an increased sodium pump molecular activity relative to other ectotherms. Phospholipids from all tissues of the octopus were highly polyunsaturated and contained high concentrations of the omega-3 polyunsaturate, docosahexaenoic acid (22:6 (n-3)). In contrast, phospholipids from bearded dragon tissues contained higher proportions of monounsaturates and lower proportions of polyunsaturates. Sodium pump molecular activity was only moderately elevated in tissues of the octopus compared to the bearded dragon, despite the much greater level of polyunsaturation in octopus membranes. When the current data were combined with data for the ectothermic cane toad, a significant (P = 0.003) correlation was observed between sodium pump molecular activity and the content of 22:6 (n-3) in the surrounding membrane. These results are discussed in relation to recent work which shows a similar relationship in endotherms.

  5. Metformin regulates hepatic lipid metabolism through activating AMP-activated protein kinase and inducing ATGL in laying hens.

    PubMed

    Chen, Wei-Lu; Wei, Hen-Wei; Chiu, Wen-Zan; Kang, Ching-Hui; Lin, Ting-Han; Hung, Chien-Ching; Chen, Ming-Chun; Shieh, Ming-Song; Lee, Chin-Cheng; Lee, Horng-Mo

    2011-12-05

    Although many clinical trials have showed that metformin improves non-alcoholic fatty liver disease, which is a common liver disease associated with hepatic enzyme abnormalities, an animal model is required to investigate the effects of altered gene expression and post-translational processing (proteins) in mediating the observed responses. Laying hens appear to develop fatty livers, as in the case in human beings, when ingesting energy in excess of maintenance, and they can be used as an animal model for observing hepatic steatosis. The aim of this study was to investigate whether metformin could improve the non-alcoholic fatty liver of laying hens and to examine the possible mechanisms of lipid-lowering effects. Forty-eight Leghorn laying hens of Hy-Line variety W-36 - 44 weeks with 64.8% hen-day egg production - were randomly assigned into 4 treatments, each receiving 0, 10, 30, or 100mg of metformin with saline per kg body weight by daily wing vein injection. Results showed that, compared with the control, significant decreases existed in the laying rates; plasma triglyceride, cholesterol, and insulin levels; body weights; abdominal fat weights; hepatic lipid contents; and hepatic fatty acid synthase expression of layers receiving 30 or 100mg per kg body weight, whereas significant increases in their hepatic 5'adenosine monophosphate-activated protein kinase, acyl-CoA carboxylase phosphorylation, adipose triglyceride lipase, and carnitine palmitoyl transferase-1 expression were observed. These data suggest that metformin could reduce lipid deposits in the liver and that the laying hen is a valuable animal model for studying hepatic steatosis.

  6. Effect of sound wave stress on antioxidant enzyme activities and lipid peroxidation of Dendrobium candidum.

    PubMed

    Li, Biao; Wei, Jinmin; Wei, Xiaolan; Tang, Kun; Liang, Yilong; Shu, Kunxian; Wang, Bochu

    2008-06-01

    The effect of sound wave stress on important medicinal plant, Dendrobium candidum Wall. ex Lindl, was investigated, including the responses on malondialdehyde (MDA) content, the activities change of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). Results were found that the activities of SOD, CAT, POD and APX enhanced totally in different organs of D. candidum, as leaves, stems and roots, in response to the stress. Furthermore there happened similar shift of antioxidant enzymes activities, which increased in the initial stimulation and decreased afterwards. Data showed SOD, CAT, POD and APX activities ascended to max at day 9, 6, 9 and 12 in leaves, at day 9, 6, 12 and 9 in stems, and at day 12, 6, 9 and 9 in roots, respectively. As a lipid peroxidation parameter, MDA content in different organs increased in the beginning, dropped afterward, and increased again in the late. Anyway the total trend was the rise of MDA level compared to the control. It was interesting that the MDA content appeared the lowest levels almost when the antioxidant enzymes activities were up to the highest. Our results demonstrated the different organs of D. candidum might produce accumulation of active oxygen species (AOS) under initial treatment of sound wave stress. Later AOS might start to reduce due to the enhancement of antioxidant enzymes activities treated by the stress. The data revealed that the antioxidant metabolism was to be important in determining the ability of plants to survive in sound stress, and the up regulation of these enzymes activities would help to reduce the build up of AOS, which could protect plant cells from oxidative damage. Moreover, different cell compartments might activate different defensive system to reduce excessive amount of AOS. Finally the mechanism of this action was also discussed simply.

  7. Peroxisome proliferator-activated receptor ligands regulate lipid content, metabolism, and composition in fetal lungs of diabetic rats.

    PubMed

    Kurtz, M; Capobianco, E; Careaga, V; Martinez, N; Mazzucco, M B; Maier, M; Jawerbaum, A

    2014-03-01

    Maternal diabetes impairs fetal lung development. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors relevant in lipid homeostasis and lung development. This study aims to evaluate the effect of in vivo activation of PPARs on lipid homeostasis in fetal lungs of diabetic rats. To this end, we studied lipid concentrations, expression of lipid metabolizing enzymes and fatty acid composition in fetal lungs of control and diabetic rats i) after injections of the fetuses with Leukotriene B4 (LTB4, PPARα ligand) or 15deoxyΔ(12,14)prostaglandin J2 (15dPGJ2, PPARγ ligand) and ii) fed during pregnancy with 6% olive oil- or 6% safflower oil-supplemented diets, enriched with PPAR ligands were studied. Maternal diabetes increased triglyceride concentrations and decreased expression of lipid-oxidizing enzymes in fetal lungs of diabetic rats, an expression further decreased by LTB4 and partially restored by 15dPGJ2 in lungs of male fetuses in the diabetic group. In lungs of female fetuses in the diabetic group, maternal diets enriched with olive oil increased triglyceride concentrations and fatty acid synthase expression, while those enriched with safflower oil increased triglyceride concentrations and fatty acid transporter expression. Both olive oil- and safflower oil-supplemented diets decreased cholesterol and cholesteryl ester concentrations and increased the expression of the reverse cholesterol transporter ATP-binding cassette A1 in fetal lungs of female fetuses of diabetic rats. In fetal lungs of control and diabetic rats, the proportion of polyunsaturated fatty acids increased with the maternal diets enriched with olive and safflower oils. Our results revealed important changes in lipid metabolism in fetal lungs of diabetic rats, and in the ability of PPAR ligands to modulate the composition of lipid species relevant in the lung during the perinatal period.

  8. Xenoreceptors CAR and PXR activation and consequences on lipid metabolism, glucose homeostasis, and inflammatory response.

    PubMed

    Moreau, Amélie; Vilarem, Marie José; Maurel, Patrick; Pascussi, Jean Marc

    2008-01-01

    Xenobiotic and drug metabolism and transport are managed by a large number of genes coordinately regulated by at least three nuclear receptors or xenosensors: aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR, NR1I3), and pregnane X receptor (PXR, NR1I2). Initially characterized as xenosensors, it is now evident that CAR and PXR also trigger pleiotropic effects on liver function. Recent studies have shown the existence of crosstalk between xenosensors and other nuclear receptors or transcription factors controlling endogenous signaling pathways which regulate physiological functions. This review is focused on recent observations showing that activation of CAR and PXR alters lipid metabolism, glucose homeostasis, and inflammation by interfering with HNF4alpha, FoxO1, FoxA2, PGC1alpha, or NFkB p65. Such crosstalks explain clinical observations and provide molecular mechanisms allowing understanding how xenobiotics and drugs may affect physiological functions and provoke endocrine disruptions.

  9. LIPID PEROXIDATION GENERATES BIOLOGICALLY ACTIVE PHOSPHOLIPIDS INCLUDING OXIDATIVELY N-MODIFIED PHOSPHOLIPIDS

    PubMed Central

    Davies, Sean S.; Guo, Lilu

    2014-01-01

    Peroxidation of membranes and lipoproteins converts “inert” phospholipids into a plethora of oxidatively modified phospholipids (oxPL) that can act as signaling molecules. In this review, we will discuss four major classes of oxPL: mildly oxygenated phospholipids, phospholipids with oxidatively truncated acyl chains, phospholipids with cyclized acyl chains, and phospholipids that have been oxidatively N-modified on their headgroups by reactive lipid species. For each class of oxPL we will review the chemical mechanisms of their formation, the evidence for their formation in biological samples, the biological activities and signaling pathways associated with them, and the catabolic pathways for their elimination. We will end by briefly highlighting some of the critical questions that remain about the role of oxPL in physiology and disease. PMID:24704586

  10. The stromal cell-surface protease fibroblast activation protein-α localizes to lipid rafts and is recruited to invadopodia.

    PubMed

    Knopf, Julia D; Tholen, Stefan; Koczorowska, Maria M; De Wever, Olivier; Biniossek, Martin L; Schilling, Oliver

    2015-10-01

    Fibroblast activation protein alpha (FAPα) is a cell surface protease expressed by cancer-associated fibroblasts in the microenvironment of most solid tumors. As there is increasing evidence for proteases having non-catalytic functions, we determined the FAPα interactome in cancer-associated fibroblasts using the quantitative immunoprecipitation combined with knockdown (QUICK) method. Complex formation with adenosin deaminase, erlin-2, stomatin, prohibitin, Thy-1 membrane glycoprotein, and caveolin-1 was further validated by immunoblotting. Co-immunoprecipitation (co-IP) of the known stoichiometric FAPα binding partner dipeptidyl-peptidase IV (DPPIV) corroborated the proteomic strategy. Reverse co-IPs validated the FAPα interaction with caveolin-1, erlin-2, and stomatin while co-IP upon RNA-interference mediated knock-down of DPPIV excluded adenosin deaminase as a direct FAPα interaction partner. Many newly identified FAPα interaction partners localize to lipid rafts, including caveolin-1, a widely-used marker for lipid raft localization. We hypothesized that this indicates a recruitment of FAPα to lipid raft structures. In density gradient centrifugation, FAPα co-fractionates with caveolin-1. Immunofluorescence optical sectioning microscopy of FAPα and lipid raft markers further corroborates recruitment of FAPα to lipid rafts and invadopodia. FAPα is therefore an integral component of stromal lipid rafts in solid tumors. In essence, we provide one of the first interactome analyses of a cell surface protease and translate these results into novel biological aspects of a marker protein for cancer-associated fibroblasts.

  11. Effects of water activity on the lipid oxidation and antioxidants of dried laver (porphyra) during storage in the dark.

    PubMed

    Choe, Eunok; Oh, Soojung

    2013-08-01

    Lipid oxidation and antioxidant degradation in dried laver (Porphyra) were determined during storage at water activities (Aw ) of 0.11, 0.30, 0.51, 0.75, or 0.89 in the dark at 40 °C for 15 d. Lipid oxidation was evaluated by measuring peroxide value (POV) and conjugated dienoic acid (CDA) contents, and fatty acid composition was analyzed by gas chromatography. Contents of polyphenols, tocopherols, and porphyran were determined by spectrophotometry, HPLC, and gravimetry, respectively. The POV and CDA contents of the dried laver lipids increased during storage as Aw increased from 0.11 to 0.30, 0.51, 0.75, and 0.89, whereas the relative content of eicosapentaenoic acid was decreased; however, the contents of polyphenols, α-tocopherol, and porphyran in dried laver showed the reverse phenomena. Lipid oxidation and antioxidant degradation in dried laver sharply increased at an Aw of 0.51. Polyphenols, α-tocopherol, and porphyran contributed to reduction of lipid oxidation in dried laver. The degree of lipid oxidation of dried laver was more dependent on the concentration of α-tocopherol than that of either polyphenols or porphyran during storage in the dark. The results strongly suggest that the quality of dried laver can be improved by preserving tocopherols as much as possible while decreasing A(w) during storage.

  12. Ex Vivo Antioxidant Activity of Selected Medicinal Plants against Fenton Reaction-Mediated Oxidation of Biological Lipid Substrates

    PubMed Central

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha; Urooj, Asna

    2015-01-01

    Free radical-mediated oxidation is often linked to various degenerative diseases. Biological substrates with lipids as major components are susceptible to oxygen-derived lipid peroxidation due to their composition. Lipid peroxide products act as biomarkers in evaluating the antioxidant potential of various plants and functional foods. The study focused on evaluation of the antioxidant potential of two extracts (methanol and 80% methanol) of four medicinal plants, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, against Fenton reaction-mediated oxidation of three biological lipid substrates; cholesterol, low-density lipoprotein, and brain homogenate. The antioxidant activity of the extracts was measured by thiobarbituric acid reactive substances method. Also, the correlation between the polyphenol, flavonoid content, and the antioxidant activity in biological substrates was analyzed. Results indicated highest antioxidant potential by 80% methanol extract of Canthium parviflorum (97.55%), methanol extract of Andrographis paniculata (72.15%), and methanol extract of Canthium parviflorum (49.55%) in cholesterol, low-density lipoprotein, and brain, respectively. The polyphenol and flavonoid contents of methanol extract of Andrographis paniculata in cholesterol (r = 0.816) and low-density lipoprotein (r = 0.948) and Costus speciosus in brain (r = 0.977, polyphenols, and r = 0.949, flavonoids) correlated well with the antioxidant activity. The findings prove the antioxidant potential of the selected medicinal plants against Fenton reaction in biological lipid substrates. PMID:26933511

  13. Dermal quercetin lipid nanocapsules: Influence of the formulation on antioxidant activity and cellular protection against hydrogen peroxide.

    PubMed

    Hatahet, T; Morille, M; Shamseddin, A; Aubert-Pouëssel, A; Devoisselle, J M; Bégu, S

    2017-02-25

    Quercetin is a plant flavonoid with strong antioxidant and antiinflammatory properties interesting for skin protection. However, its poor water solubility limits its penetration and so its efficiency on skin. For this purpose, quercetin lipid nanocapsules were formulated implementing phase inversion technique wherein several modifications were introduced to enhance quercetin loading. Quercetin lipid nanocapsules were formulated with two particle size range, (50nm and 20nm) allowing a drug loading of 18.6 and 32mM respectively. The successful encapsulation of quercetin within lipid nanocapsules increased its apparent water solubility by more than 5000 fold (from 0.5μg/ml to about 5mg/ml). The physicochemical properties of these formulations such as surface charge, stability and morphology were characterized. Lipid nanocapsules had spherical shape and were stable for 28days at 25°C. Quercetin release from lipid nanocapsules was studied and revealed a prolonged release kinetics during 24h. Using DPPH assay, we demonstrated that the formulation process of lipid nanocapsules did not modify the antioxidant activity of quercetin in vitro (92.3%). With the goal of a future dermal application, quercetin lipid nanocapsules were applied to THP-1 monocytes and proved the cellular safety of the formulation up to 2μg/ml of quercetin. Finally, formulated quercetin was as efficient as the crude form in the protection of THP-1 cells from oxidative stress by exogenous hydrogen peroxide. With its lipophilic nature and occlusive effect on skin, lipid nanocapsules present a promising strategy to deliver quercetin to skin tissue and can be of value for other poorly water soluble drug candidates.

  14. Bactericidal activities of cathelicidin LL-37 and select cationic lipids against the hypervirulent Pseudomonas aeruginosa strain LESB58.

    PubMed

    Wnorowska, Urszula; Niemirowicz, Katarzyna; Myint, Melissa; Diamond, Scott L; Wróblewska, Marta; Savage, Paul B; Janmey, Paul A; Bucki, Robert

    2015-07-01

    Pseudomonas aeruginosa Liverpool epidemic strain (LES) infections in cystic fibrosis (CF) patients are associated with transmissibility and increased patient morbidity. This study was designed to assess the in vitro activities of cathelicidin LL-37 peptide (LL-37) and select cationic lipids against Pseudomonas aeruginosa LESB58 in CF sputum and in a setting mimicking the CF airway. We found that LL-37 naturally present in airway surface fluid and some nonpeptide cationic lipid molecules such as CSA-13, CSA-90, CSA-131, and D2S have significant, but broadly differing, bactericidal activities against P. aeruginosa LESB58. We observed strong inhibition of LL-37 bactericidal activity in the presence of purified bacteriophage Pf1, which is highly expressed by P. aeruginosa LES, but the activities of the cationic lipids CSA-13 and CSA-131 were not affected by this polyanionic virus. Additionally, CSA-13 and CSA-131 effectively prevent LESB58 biofilm formation, which is stimulated by Pf1 bacteriophage, DNA, or F-actin. CSA-13 and CSA-131 display strong antibacterial activities against different clinical strains of P. aeruginosa, and their activities against P. aeruginosa LESB58 and Xen5 strains were maintained in CF sputum. These data indicate that synthetic cationic lipids (mimics of natural antimicrobial peptides) are suitable for developing an effective treatment against CF lung P. aeruginosa infections, including those caused by LES strains.

  15. Bactericidal Activities of Cathelicidin LL-37 and Select Cationic Lipids against the Hypervirulent Pseudomonas aeruginosa Strain LESB58

    PubMed Central

    Wnorowska, Urszula; Niemirowicz, Katarzyna; Myint, Melissa; Diamond, Scott L.; Wróblewska, Marta; Savage, Paul B.; Janmey, Paul A.

    2015-01-01

    Pseudomonas aeruginosa Liverpool epidemic strain (LES) infections in cystic fibrosis (CF) patients are associated with transmissibility and increased patient morbidity. This study was designed to assess the in vitro activities of cathelicidin LL-37 peptide (LL-37) and select cationic lipids against Pseudomonas aeruginosa LESB58 in CF sputum and in a setting mimicking the CF airway. We found that LL-37 naturally present in airway surface fluid and some nonpeptide cationic lipid molecules such as CSA-13, CSA-90, CSA-131, and D2S have significant, but broadly differing, bactericidal activities against P. aeruginosa LESB58. We observed strong inhibition of LL-37 bactericidal activity in the presence of purified bacteriophage Pf1, which is highly expressed by P. aeruginosa LES, but the activities of the cationic lipids CSA-13 and CSA-131 were not affected by this polyanionic virus. Additionally, CSA-13 and CSA-131 effectively prevent LESB58 biofilm formation, which is stimulated by Pf1 bacteriophage, DNA, or F-actin. CSA-13 and CSA-131 display strong antibacterial activities against different clinical strains of P. aeruginosa, and their activities against P. aeruginosa LESB58 and Xen5 strains were maintained in CF sputum. These data indicate that synthetic cationic lipids (mimics of natural antimicrobial peptides) are suitable for developing an effective treatment against CF lung P. aeruginosa infections, including those caused by LES strains. PMID:25870055

  16. HCV core protein induces hepatic lipid accumulation by activating SREBP1 and PPAR{gamma}

    SciTech Connect

    Kim, Kook Hwan; Hong, Sung Pyo; Kim, KyeongJin; Park, Min Jung; Kim, Kwang Jin; Cheong, JaeHun . E-mail: molecule85@pusan.ac.kr

    2007-04-20

    Hepatic steatosis is a common feature in patients with chronic hepatitis C virus (HCV) infection. HCV core protein plays an important role in the development of hepatic steatosis in HCV infection. Because SREBP1 (sterol regulatory element binding protein 1) and PPAR{gamma} (peroxisome proliferators-activated receptor {gamma}) are involved in the regulation of lipid metabolism of hepatocyte, we sought to determine whether HCV core protein may impair the expression and activity of SREBP1 and PPAR{gamma}. In this study, it was demonstrated that HCV core protein increases the gene expression of SREBP1 not only in Chang liver, Huh7, and HepG2 cells transiently transfected with HCV core protein expression plasmid, but also in Chang liver-core stable cells. Furthermore, HCV core protein enhanced the transcriptional activity of SREBP1. In addition, HCV core protein elevated PPAR{gamma} transcriptional activity. However, HCV core protein had no effect on PPAR{gamma} gene expression. Finally, we showed that HCV core protein stimulates the genes expression of lipogenic enzyme and fatty acid uptake associated protein. Therefore, our finding provides a new insight into the mechanism of hepatic steatosis by HCV infection.

  17. Influence of fine structure of lipid A on Limulus amebocyte lysate clotting and toxic activities.

    PubMed Central

    Takayama, K; Qureshi, N; Raetz, C R; Ribi, E; Peterson, J; Cantrell, J L; Pearson, F C; Wiggins, J; Johnson, A G

    1984-01-01

    We examined the relationship between the fine structure of lipid A and the toxicity of endotoxin or lipopolysaccharides as measured by the Limulus amebocyte lysate (LAL), rabbit pyrogenicity, chicken embryo lethal dose, and dermal Shwartzman reaction tests. Lipid A and lipid A-like compounds obtained from deep-rough mutants of Salmonella spp. and Escherichia coli had a wide range of structural variations. These compounds included native lipopolysaccharides, diphosphoryl and monophosphoryl lipid A's, and lipid X (a monosaccharide). The LAL test was positive for all lipids tested with lysates from Travenol Laboratories and from Associates of Cape Cod (2.9 X 10(3) to 2.6 X 10(7) endotoxin units per mg), except for O-deacylated and dephosphorylated lipid X, which were negative. The Mallinckrodt lysate gave negative tests for lipid X. In the rabbit pyrogenicity and chicken embryo lethal dose tests, only native lipopolysaccharide and diphosphoryl lipid A's were judged toxic. The Shwartzman reaction was positive for a specific purified diphosphoryl lipid A (thin-layer chromatography-3 fraction) but negative for the purified monophosphoryl lipid A (also a thin-layer chromatography-3 fraction). These results show that the LAL test is not a valid measure of all parameters of toxicity of a lipid A or lipid A-like compound and can yield false-positive results. However, these findings are not in conflict with the widespread use of the LAL assay for pyrogens in the pharmaceutical industry since a good correlation exists between LAL results and pyrogenicity when undegraded endotoxin is evaluated in parallel assays. Images PMID:6378795

  18. Structure-activity correlation in transfection promoted by pyridinium cationic lipids.

    PubMed

    Parvizi-Bahktar, P; Mendez-Campos, J; Raju, L; Khalique, N A; Jubeli, E; Larsen, H; Nicholson, D; Pungente, M D; Fyles, T M

    2016-03-21

    The efficiency of the transfection of a plasmid DNA encoding a galactosidase promoted by a series of pyridinium lipids in mixtures with other cationic lipids and neutral lipids was assessed in CHO-K1 cells. We identify key molecular parameters of the lipids in the mixture - clog P, lipid length, partial molar volume - to predict the morphology of the lipid-DNA lipoplex and then correlate these same parameters with transfection efficiency in an in vitro assay. We define a Transfection Index that provides a linear correlation with normalized transfection efficiency over a series of 90 different lipoplex compositions. We also explore the influence of the same set of molecular parameters on the cytotoxicity of the formulations.

  19. Oncogene KRAS activates fatty acid synthase, resulting in specific ERK and lipid signatures associated with lung adenocarcinoma.

    PubMed

    Gouw, Arvin M; Eberlin, Livia S; Margulis, Katherine; Sullivan, Delaney K; Toal, Georgia G; Tong, Ling; Zare, Richard N; Felsher, Dean W

    2017-04-11

    KRAS gene mutation causes lung adenocarcinoma. KRAS activation has been associated with altered glucose and glutamine metabolism. Here, we show that KRAS activates lipogenesis, and this activation results in distinct proteomic and lipid signatures. By gene expression analysis, KRAS is shown to be associated with a lipogenesis gene signature and specific induction of fatty acid synthase (FASN). Through desorption electrospray ionization MS imaging (DESI-MSI), specific changes in lipogenesis and specific lipids are identified. By the nanoimmunoassay (NIA), KRAS is found to activate the protein ERK2, whereas ERK1 activation is found in non-KRAS-associated human lung tumors. The inhibition of FASN by cerulenin, a small molecule antibiotic, blocked cellular proliferation of KRAS-associated lung cancer cells. Hence, KRAS is associated with activation of ERK2, induction of FASN, and promotion of lipogenesis. FASN may be a unique target for KRAS-associated lung adenocarcinoma remediation.

  20. Designed low amphipathic peptides with alpha-helical propensity exhibiting antimicrobial activity via a lipid domain formation mechanism.

    PubMed

    Yamamoto, Naoki; Tamura, Atsuo

    2010-05-01

    Although several low amphipathic peptides have been known to exhibit antimicrobial activity, their mode of action has not been completely elucidated. In this study, using designed low amphipathic peptides that retain different alpha-helical content and hydrophobicity, we attempted to investigate the mechanism of these properties. Calorimetric and thermodynamic analyses demonstrated that the peptides induce formation of two lipid domains in an anionic liposome at a high peptide-to-lipid ratio. On the other hand, even at a low peptide-to-lipid ratio, they caused minimal membrane damage, such as flip-flop of membrane lipids or leakage of calcein molecules from liposomes, and never translocated across membranes. Interaction energies between the peptides and anionic liposomes showed good correlation with antimicrobial activity for both Escherichia coli and Bacillus subtilis. We thus propose that the domain formation mechanism in which antimicrobial peptides exhibit activity solely by forming lipid domains without membrane damage is a major determinant of the antimicrobial activity of low amphipathic peptides. These peptides appear to stiffen the membrane such that it is deprived of the fluidity necessary for biological functions. We also showed that to construct the lipid domains, peptides need not form stable and cooperative structures. Rather, it is essential for peptides to only interact tightly with the membrane interface via strong electrostatic interactions, and slight differences in binding strength are invoked by differences in hydrophobicity. The peptides thus designed might pave the way for "clean" antimicrobial reagents that never cause release of membrane elements and efflux of their inner components.

  1. Inhibition of SREBP transcriptional activity by a boron-containing compound improves lipid homeostasis in diet-induced obesity.

    PubMed

    Zhao, Xiaoping; Xiaoli; Zong, Haihong; Abdulla, Arian; Yang, Ellen S T; Wang, Qun; Ji, Jun-Yuan; Pessin, Jeffrey E; Das, Bhaskar C; Yang, Fajun

    2014-07-01

    Dysregulation of lipid homeostasis is intimately associated with obesity, type 2 diabetes, and cardiovascular diseases. Sterol regulatory-element binding proteins (SREBPs) are the master regulators of lipid biosynthesis. Previous studies have shown that the conserved transcriptional cofactor Mediator complex is critically required for the SREBP transcriptional activity, and recruitment of the Mediator complex to the SREBP transactivation domains (TADs) is through the MED15-KIX domain. Recently, we have synthesized several boron-containing small molecules. Among these novel compounds, BF175 can specifically block the binding of MED15-KIX to SREBP1a-TAD in vitro, resulting in an inhibition of the SREBP transcriptional activity and a decrease of SREBP target gene expression in cultured hepatocytes. Furthermore, BF175 can improve lipid homeostasis in the mouse model of diet-induced obesity. Compared with the control, BF175 treatment decreased the expression of SREBP target genes in mouse livers and decreased hepatic and blood levels of lipids. These results suggest that blocking the interaction between SREBP-TADs and the Mediator complex by small molecules may represent a novel approach for treating diseases with aberrant lipid homeostasis.

  2. Serum levels of lipids, lipoproteins and paraoxonase activity in pre-eclampsia.

    PubMed

    Demir, B; Demir, S; Atamer, Y; Guven, S; Atamer, A; Kocyigit, Y; Hekimoglu, A; Toprak, G

    2011-01-01

    Serum paraoxonase 1 (PON1) activity and the oxidation of lipoproteins were investigated in 35 women with pre-eclampsia and in 35 healthy control women with normal pregnancies. Blood pressure, body mass index (BMI), serum levels of total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and lipoprotein (a) (Lp[a]), and PON1 activity were assessed. There were no significant between-group differences in subject age, gestational age at diagnosis of pre-eclampsia, BMI, serum total cholesterol, triglycerides, LDL and ApoB levels. Mean systolic and diastolic blood pressures and serum Lp(a) were significantly higher in subjects with pre-eclampsia than in controls. Mean serum HDL, ApoA1 and PON1 activity were significantly lower in subjects with pre-eclampsia compared with controls. In conclusion, lipids and oxidized lipoproteins may play important roles in the pathogenesis of pre-eclampsia.

  3. Modulation of CD14 and TLR4.MD-2 activities by a synthetic lipid A mimetic

    PubMed Central

    Cighetti, Roberto; Ciaramelli, Carlotta; Sestito, Stefania Enza; Zanoni, Ivan; Kubik, Łukasz; Ardá-Freire, Ana; Calabrese, Valentina; Granucci, Francesca; Jerala, Roman; Martín-Santamaría, Sonsoles; Jiménez-Barbero, Jesus

    2014-01-01

    Monosaccharide lipid A mimetics composed by a glucosamine core linked to two fatty acid chains and bearing one or two phosphates have been synthesized. While compounds 1 and 2, with one phosphate group, were practically inactive in inhibiting LPS-induced TLR4 signaling and cytokine production in HEK-blue™ cells and murine macrophages, compound 3 with two phosphates was found to be active in efficiently inhibiting TLR4 signal in both cell types. The direct interaction of molecule 3 with MD-2 co-receptor has been investigated by means of NMR and molecular modeling/docking analysis. This compound also interacts directly with CD14 receptor, stimulating its internalization by endocytosis. Experiments on macrophages show that the effect on CD14 reinforces the activity on MD-2.TLR4, because compound 3 activity is higher when CD14 is important for TLR4 signaling i,e, at low LPS concentration. The dual MD-2 and CD14 targeting, accompanied by good solubility in water and lack of toxicity, suggests the use of monosaccharide 3 as a lead compound to develop drugs directed against TLR4-related syndromes. PMID:24339336

  4. Lipid-lowering Activity of Natural and Semi-Synthetic Sterols and Stanols.

    PubMed

    Taha, Dhiaa A; Wasan, Ellen K; Wasan, Kishor M; Gershkovich, Pavel

    2015-01-01

    Consumption of plant sterols/ stanols has long been demonstrated to reduce plasma cholesterol levels. The objective of this review is to demonstrate the lipid-lowering activity and anti-atherogenic effects of natural and semi-synthetic plant sterols/ stanols based on evidence from cell-culture studies, animal studies and clinical trials. Additionally, this review highlights certain molecular mechanisms by which plant sterols/ stanols lower plasma cholesterol levels with a special emphasis on factors that affect the cholesterol-lowering activity of plant sterols/stanols. The crystalline nature and the poor oil solubility of these natural products could be important factors that limit their cholesterol-lowering efficiency. Several attempts have been made to improve the cholesterol-lowering activity by enhancing the bioavailability of crystalline sterols and stanols. Approaches involved reduction of the crystal size and/or esterification with fatty acids from vegetable or fish oils. However, the most promising approach in this context is the chemical modification of plant sterols /stanols into water soluble disodium ascorbyl phytostanyl phosphates analogue by esterification with ascorbic acid. This novel semi-synthetic stanol derivative has improved efficacy over natural plant sterols/ stanols and can provide additional benefits by combining the cholesterol-lowering properties of plant stanols with the antioxidant potential of ascorbic acid. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

  5. Mitofusin 2 decreases intracellular lipids in macrophages by regulating peroxisome proliferator-activated receptor-γ

    SciTech Connect

    Liu, Chun; Ge, Beihai; He, Chao; Zhang, Yi; Liu, Xiaowen; Liu, Kejian; Qian, Cuiping; Zhang, Yu; Peng, Wenzhong; Guo, Xiaomei

    2014-07-18

    Highlights: • Mfn2 decreases cellular lipid accumulation by activating cholesterol transporters. • PPARγ is involved in the Mfn2-mediated increase of cholesterol transporter expressions. • Inactivation of ERK1/2 and p38 is involved in Mfn2-induced PPARγ expression. - Abstract: Mitofusin 2 (Mfn2) inhibits atherosclerotic plaque formation, but the underlying mechanism remains elusive. This study aims to reveal how Mfn2 functions in the atherosclerosis. Mfn2 expression was found to be significantly reduced in arterial atherosclerotic lesions of both mice and human compared with healthy counterparts. Here, we observed that Mfn2 increased cellular cholesterol transporter expression in macrophages by upregulating peroxisome proliferator-activated receptor-γ, an effect achieved at least partially by inhibiting extracellular signal-regulated kinase1/2 (ERK1/2) and p38 mitogen-activated protein kinases (MAPKs) pathway. These findings provide insights into potential mechanisms of Mfn2-mediated alterations in cholesterol transporter expression, which may have significant implications for the treatment of atherosclerotic heart disease.

  6. meso-Dihydroguaiaretic acid inhibits hepatic lipid accumulation by activating AMP-activated protein kinase in human HepG2 cells.

    PubMed

    Lee, Myoung-Su; Kim, Kyung Jin; Kim, Daeyoung; Lee, Kyung-Eun; Hwang, Jae-Kwan

    2011-01-01

    Hepatic lipid accumulation is a major risk factor for dyslipidemia, nonalcoholic fatty liver disease, and insulin resistance. The present study was conducted to evaluate hypolipidemic effects of meso-dihydroguaiaretic acid (MDA), anti-oxidative and anti-inflammatory compound isolated from the Myristica fragrans HOUTT., by oil red O staining, reverse transcription-polymerase chain reaction (RT-PCR), and Western blot. MDA significantly inhibited insulin-induced hepatic lipid accumulation in a dose-dependent manner. The lipid-lowering effect of MDA was accompanied by increased expression of proteins involved in fatty acid oxidation and decreased expression of lipid synthetic proteins. In addition, MDA activated AMP-activated protein kinase (AMPK) as determined by phosphorylation of acetyl-CoA carboxylase (ACC), a downstream target of AMPK. The effects of MDA on lipogenic protein expression were suppressed by pretreatment with compound C, an AMPK inhibitor. Taken together, these findings show that MDA inhibits insulin-induced lipid accumulation in human HepG2 cells by suppressing expression of lipogenic proteins through AMPK signaling, suggesting a potent lipid-lowering agent.

  7. Altered linkage of hydroxyacyl chains in lipid A of Campylobacter jejuni reduces TLR4 activation and antimicrobial resistance.

    PubMed

    van Mourik, Andries; Steeghs, Liana; van Laar, Jacoline; Meiring, Hugo D; Hamstra, Hendrik-Jan; van Putten, Jos P M; Wösten, Marc M S M

    2010-05-21

    Modification of the lipid A moiety of bacterial lipopolysaccharide influences cell wall properties, endotoxic activity, and bacterial resistance to antimicrobial peptides. Known modifications are variation in the number or length of acyl chains and/or attached phosphoryl groups. Here we identified two genes (gnnA and gnnB) in the major foodborne pathogen Campylobacter jejuni that enable the synthesis of a GlcN3N precursor UDP 2-acetamido-3-amino-2,3-dideoxy-alpha-D-glucopyranose (UDP-GlcNAc3N) in the lipid A backbone. Mass spectrometry of purified lipooligosaccharide verified that the gene products facilitate the formation of a 2,3-diamino-2,3-dideoxy-D-glucose (GlcN3N) disaccharide lipid A backbone when compared with the beta-1'-6-linked D-glucosamine (GlcN) disaccharide observed in Escherichia coli lipid A. Functional assays showed that inactivation of the gnnA or gnnB gene enhanced the TLR4-MD2-mediated NF-kappaB activation. The mutants also displayed increased susceptibility to killing by the antimicrobial peptides polymyxin B, colistin and the chicken cathelicidin-1. The gnnA and gnnB genes are organized in one operon with hemH, encoding a ferrochelatase catalyzing the last step in heme biosynthesis. These results indicate that lipid A modification resulting in amide-linked acyl chains in the lipid A is an effective mechanism to evade activation of the innate host defense and killing by antimicrobial peptides.

  8. The synthetic cationic lipid diC14 activates a sector of the Arabidopsis defence network requiring endogenous signalling components.

    PubMed

    Cambiagno, Damián Alejandro; Lonez, Caroline; Ruysschaert, Jean-Marie; Alvarez, María Elena

    2015-12-01

    Natural and synthetic elicitors have contributed significantly to the study of plant immunity. Pathogen-derived proteins and carbohydrates that bind to immune receptors, allow the fine dissection of certain defence pathways. Lipids of a different nature that act as defence elicitors, have also been studied, but their specific effects have been less well characterized, and their receptors have not been identified. In animal cells, nanoliposomes of the synthetic cationic lipid 3-tetradecylamino-tert-butyl-N-tetradecylpropionamidine (diC14) activate the TLR4-dependent immune cascade. Here, we have investigated whether this lipid induces Arabidopsis defence responses. At the local level, diC14 activated early and late defence gene markers (FRK1, WRKY29, ICS1 and PR1), acting in a dose-dependent manner. This lipid induced the salicylic acid (SA)-dependent, but not jasmonic acid (JA)-dependent, pathway and protected plants against Pseudomonas syringae pv. tomato (Pst), but not Botrytis cinerea. diC14 was not toxic to plant or pathogen, and potentiated pathogen-induced callose deposition. At the systemic level, diC14 induced PR1 expression and conferred resistance against Pst. diC14-induced defence responses required the signalling protein EDS1, but not NDR1. Curiously, the lipid-induced defence gene expression was lower in the fls2/efr/cerk1 triple mutant, but still unchanged in the single mutants. The amidine headgroup and chain length were important for its activity. Given the robustness of the responses triggered by diC14, its specific action on a defence pathway and the requirement for well-known defence components, this synthetic lipid is emerging as a useful tool to investigate the initial events involved in plant innate immunity.

  9. Regulation of lipid synthesis genes and milk fat production in human mammary epithelial cells during secretory activation.

    PubMed

    Mohammad, Mahmoud A; Haymond, Morey W

    2013-09-15

    Expression of genes for lipid biosynthetic enzymes during initiation of lactation in humans is unknown. Our goal was to study mRNA expression of lipid metabolic enzymes in human mammary epithelial cell (MEC) in conjunction with the measurement of milk fatty acid (FA) composition during secretory activation. Gene expression from mRNA isolated from milk fat globule (MFG) and milk FA composition were measured from 6 h to 42 days postpartum in seven normal women. Over the first 96 h postpartum, daily milk fat output increased severalfold and mirrored expression of genes for all aspects of lipid metabolism and milk FA production, including lipolysis at the MEC membrane, FA uptake from blood, intracellular FA transport, de novo FA synthesis, FA and glycerol activation, FA elongation, FA desaturation, triglyceride synthesis, cholesterol synthesis, and lipid droplet formation. Expression of the gene for a key lipid synthesis regulator, sterol regulatory element-binding transcription factor 1 (SREBF1), increased 2.0-fold by 36 h and remained elevated over the study duration. Expression of genes for estrogen receptor 1, thyroid hormone-responsive protein, and insulin-induced 2 increased progressively to plateau by 96 h. In contrast, mRNA of peroxisome proliferator-activated receptor-γ decreased severalfold. With onset of lactation, increased de novo synthesis of FA was the most prominent change in milk FA composition and mirrored the expression of FA synthesis genes. In conclusion, milk lipid synthesis and secretion in humans is a complex process requiring the orchestration of a wide variety of pathways of which SREBF1 may play a primary role.

  10. Antioxidant activity and inhibitory effects of lead (Leucaena leucocephala) seed extracts against lipid oxidation in model systems.

    PubMed

    Benjakul, Soottawat; Kittiphattanabawon, Phanat; Shahidi, Fereidoon; Maqsood, Sajid

    2013-08-01

    Antioxidant activity of brown lead (Leucaena leucocephala) seed extracts with and without prior chlorophyll removal was studied in comparison with mimosine. Both extracts showed similar hydroxyl radical (HO(•)) scavenging activity, hydrogen peroxide (H2O2) scavenging activity, singlet oxygen inhibition and hypochlorous acid (HOCl) scavenging capacity (p > 0.05). Nevertheless, the extract without prior chlorophyll removal had higher oxygen radical absorbance capacity than that with prior chlorophyll removal (p < 0.05). Generally, lead seed extracts with and without prior chlorophyll removal possessed a lower antioxidant activity, compared with mimosine. When lead seed extract without prior chlorophyll removal (100 and 200 ppm) was used in different lipid oxidation model systems, including β-carotene-linoleic acid and lecithin liposome systems, the preventive effect toward lipid oxidation was dose-dependent. At the same level of use, mimosine exhibited a higher efficacy in prevention of lipid oxidation in both systems as indicated by the lower increases in thiobarbituric acid reactive substances. A similar result was obtained in minced mackerel. Therefore, lead seed extract containing mimosine could act as a natural antioxidant to prevent lipid oxidation in foods.

  11. FATTY ACIDS MODULATE TOLL-LIKE RECEPTOR 4 ACTIVATION THROUGH REGULATION OF RECEPTOR DIMERIZATION AND RECRUITMENT INTO LIPID RAFTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The saturated fatty acids acylated on Lipid A of lipopolysaccharide (LPS) or bacterial lipoproteins play critical roles in ligand recognition and receptor activation for Toll-like Receptor 4 (TLR4) and TLR2. The results from our previous studies (J Biol Chem 2003, 2004) demonstrated that saturated ...

  12. Selenium status, lipid peroxides concentration, and glutathione peroxidase activity in the blood of power station and rubber factory workers.

    PubMed

    Zachara, B A; Wasowicz, W; Sklodowska, M; Gromadzinska, J

    1987-01-01

    Concentration of selenium in whole blood and plasma, lipid peroxides in plasma, and glutathione peroxidase activities in red blood cell hemolysates and plasma were determined in 49 coal power plant workers and in 50 rubber factory workers. The results were compared with those obtained for 58 nonindustrial controls. Whole blood selenium was significantly lower and plasma lipid peroxides were significantly higher in power plant workers when compared to the nonindustrial group. In the rubber factory workers, whole blood selenium and red blood cells and plasma glutathione peroxidase activities were significantly lower than in the control group. Urinary output of selenium was also significantly decreased in rubber factory workers. Slightly elevated lipid peroxides were also observed in that group. It seems reasonable to conclude that the lower blood selenium and decreased urinary output of this element may result from increased loss of selenium with perspiration. No correlation has been observed between selenium concentration and glutathione peroxidase activity and between enzyme activity and lipid peroxides concentration in the industrial group.

  13. Enzymatic Synthesis of Structured Lipids using a Novel Cold-Active Lipase from Pichia lynferdii NRRL Y-7723

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Structured lipids (SL) were synthesized by the acidolysis of borage oil with caprylic acid using lipases. Six commercial lipases from different sources and a novel lipase from Pichia lynferdii NRRL Y-7723 were screened for their acidolysis activities and Lipozyme RM IM and NRRL Y-7723 lipase were s...

  14. Using fluorescence-activated flow cytometry to determine reactive oxygen species formation and membrane lipid peroxidation in viable boar spermatozoa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fluorescence-activated flow cytometry analyses were developed for determination of reactive oxygen species (ROS) formation and membrane lipid peroxidation in live spermatozoa loaded with, respectively, hydroethidine (HE) or the lipophilic probe 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-d...

  15. GRP1 pleckstrin homology domain: activation parameters and novel search mechanism for rare target lipid.

    PubMed

    Corbin, John A; Dirkx, Ronald A; Falke, Joseph J

    2004-12-28

    Pleckstrin homology (PH) domains play a central role in a wide array of signaling pathways by binding second messenger lipids of the phosphatidylinositol phosphate (PIP) lipid family. A given type of PIP lipid is formed in a specific cellular membrane where it is generally a minor component of the bulk lipid mixture. For example, the signaling lipid PI(3,4,5)P(3) (or PIP(3)) is generated primarily in the inner leaflet of the plasma membrane where it is believed to never exceed 0.02% of the bulk lipid. The present study focuses on the PH domain of the general receptor for phosphoinositides, isoform 1 (GRP1), which regulates the actin cytoskeleton in response to PIP(3) signals at the plasma membrane surface. The study systematically analyzes both the equilibrium and kinetic features of GRP1-PH domain binding to its PIP lipid target on a bilayer surface. Equilibrium binding measurements utilizing protein-to-membrane fluorescence resonance energy transfer (FRET) to detect GRP1-PH domain docking to membrane-bound PIP lipids confirm specific binding to PIP(3). A novel FRET competitive binding measurement developed to quantitate docking affinity yields a K(D) of 50 +/- 10 nM for GRP1-PH domain binding to membrane-bound PIP(3) in a physiological lipid mixture approximating the composition of the plasma membrane inner leaflet. This observed K(D) lies in a suitable range for regulation by physiological PIP(3) signals. Interestingly, the affinity of the interaction decreases at least 12-fold when the background anionic lipids phosphatidylserine (PS) and phosphatidylinositol (PI) are removed from the lipid mixture. Stopped-flow kinetic studies using protein-to-membrane FRET to monitor association and dissociation time courses reveal that this affinity decrease arises from a corresponding decrease in the on-rate for GRP1-PH domain docking with little or no change in the off-rate for domain dissociation from membrane-bound PIP(3). Overall, these findings indicate that the PH

  16. Influence of iron solubility and charged surface-active compounds on lipid oxidation in fatty acid ethyl esters containing association colloids.

    PubMed

    Homma, Rika; Johnson, David R; McClements, D Julian; Decker, Eric A

    2016-05-15

    The impact of iron compounds with different solubilities on lipid oxidation was studied in the presence and absence of association colloids. Iron (III) sulfate only accelerated lipid oxidation in the presence of association colloids while iron (III) oleate accelerated oxidation in the presence and absence of association colloids. Further, iron (III) oxide retarded lipid oxidation both with and without association colloids. The impact of charged association colloids on lipid oxidation in ethyl oleate was also investigated. Association colloids consisting of the anionic surface-active compound dodecyl sulphosuccinate sodium salt (AOT), cationic surface-active compound hexadecyltrimethylammonium bromide (CTAB), and nonionic surface-active compound 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100) retarded, promoted, and had no effect on lipid oxidation rates, respectively. These results indicate that the polarity of metal compounds and the charge of association colloids play a big role in lipid oxidation.

  17. Effect of lipid peroxidation on membrane-bound Ca2+-ATPase activity of the intestinal brush-border membranes.

    PubMed

    Ohta, A; Mohri, T; Ohyashiki, T

    1989-09-04

    We have studied lipid peroxidation and Ca2+-ATPase activity of the porcine intestinal brush-border membranes using a oxygen-radical-generating system consisting of dithiothreitol (DTT)/Fe2+ and tert-butyl hydroperoxide (t-BuOOH). The rates of lipid peroxidation were measured by formation of thiobarbituric acid-reactive substances (TBAR) and conjugated diene. Incubation of the membranes with DTT/Fe2+ in the absence and presence of t-BuOOH resulted in a slight (about 20%) and a marked (about 50%) inhibition of Ca2+-ATPase activity, respectively. The degree of inhibition was dependent on the hydroperoxide concentration. Addition of thiourea effectively protected Ca2+-ATPase activity but catalase and superoxide dismutase showed a slight and no effect on protection of the ATPase activity, respectively. Results of kinetic studies on the ATPase activity with varying ATP and Ca2+ concentrations revealed that the decrease in the enzyme activity by treatment with these oxidizing agents is mainly due to decrease of the Vmax value. Modification of SH groups in the membrane proteins by thiol group reagents such as N-ethylmaleimide, monoiodoacetate and monoiodacetamide did not induce the inhibition of Ca2+-ATPase activity. From these results, it is suggested that inhibition of the ATPase activity of the membranes by treatment with DTT/Fe2+ in the presence and absence of t-BuOOH is dependent on lipid peroxidation and that oxidative modification of SH groups may not be directly involved to the loss of the ATPase activity. In addition, results of the fluorescence anisotropy measurements of pyrene-labeled membranes suggested that change in the Ca2+-ATPase activity is partly related to a decrease in the membrane lipid fluidity.

  18. A subset of annular lipids is linked to the flippase activity of an ABC transporter.

    PubMed

    Bechara, Chérine; Nöll, Anne; Morgner, Nina; Degiacomi, Matteo T; Tampé, Robert; Robinson, Carol V

    2015-03-01

    Lipids are critical components of membranes that could affect the properties of membrane proteins, yet the precise compositions of lipids surrounding membrane-embedded protein complexes is often difficult to discern. Here we report that, for the heterodimeric ABC transporter TmrAB, the extent of delipidation can be controlled by timed exposure to detergent. We subsequently characterize the cohort of endogenous lipids that are extracted in contact with the membrane protein complex, and show that with prolonged delipidation the number of neutral lipids is reduced in favour of their negatively charged counterparts. We show that lipid A is retained by the transporter and that the extent of its binding decreases during the catalytic cycle, implying that lipid A release is linked to adenosine tri-phosphate hydrolysis. Together, these results enable us to propose that a subset of annular lipids is invariant in composition, with negatively charged lipids binding tightly to TmrAB, and imply a role for this exporter in glycolipid translocation.

  19. A subset of annular lipids is linked to the flippase activity of an ABC transporter

    NASA Astrophysics Data System (ADS)

    Bechara, Chérine; Nöll, Anne; Morgner, Nina; Degiacomi, Matteo T.; Tampé, Robert; Robinson, Carol V.

    2015-03-01

    Lipids are critical components of membranes that could affect the properties of membrane proteins, yet the precise compositions of lipids surrounding membrane-embedded protein complexes is often difficult to discern. Here we report that, for the heterodimeric ABC transporter TmrAB, the extent of delipidation can be controlled by timed exposure to detergent. We subsequently characterize the cohort of endogenous lipids that are extracted in contact with the membrane protein complex, and show that with prolonged delipidation the number of neutral lipids is reduced in favour of their negatively charged counterparts. We show that lipid A is retained by the transporter and that the extent of its binding decreases during the catalytic cycle, implying that lipid A release is linked to adenosine tri-phosphate hydrolysis. Together, these results enable us to propose that a subset of annular lipids is invariant in composition, with negatively charged lipids binding tightly to TmrAB, and imply a role for this exporter in glycolipid translocation.

  20. Transferrin mediated solid lipid nanoparticles containing curcumin: enhanced in vitro anticancer activity by induction of apoptosis.

    PubMed

    Mulik, Rohit S; Mönkkönen, Jukka; Juvonen, Risto O; Mahadik, Kakasaheb R; Paradkar, Anant R

    2010-10-15

    Photodegradation and low bioavailability are major hurdles for the therapeutic use of curcumin. Aim of the present study was to formulate transferrin-mediated solid lipid nanoparticles (Tf-C-SLN) to increase photostability, and enhance its anticancer activity against MCF-7 breast cancer cells. Tf-C-SLN were prepared by homogenization method and characterized by size, zeta potential, entrapment efficiency and stability, transmission electron microscopy (TEM), X-ray diffraction (XRD) and in vitro release study. Microplate analysis and flow cytometry techniques were used for cytotoxicity and apoptosis study. The physical characterization showed the suitability of method of preparation. TEM and XRD study revealed the spherical nature and entrapment of curcumin in amorphous form, respectively. The cytotoxicity, ROS and cell uptake was found to be increased considerably with Tf-C-SLN compared to curcumin solubilized surfactant solution (CSSS) and curcumin-loaded SLN (C-SLN) suggesting the targeting effect. AnnexinV-FITC/PI double staining, DNA analysis and reduced mitochondrial potential confirmed the apoptosis. The flow cytometric studies revealed that the anticancer activity of curcumin is enhanced with Tf-C-SLN compared to CSSS and C-SLN, and apoptosis is the mechanism underlying the cytotoxicity. The present study indicated the potential of Tf-C-SLN in enhancing the anticancer effect of curcumin in breast cancer cells in vitro.

  1. Antioxidant activities of essential oil mixtures toward skin lipid squalene oxidized by UV irradiation.

    PubMed

    Wei, Alfreda; Shibamoto, Takayuki

    2007-01-01

    Antioxidant activities of essential oil mixtures--thyme or clove leaf with cinnamon leaf, rose, or parsley seed--toward skin lipid, squalene oxidized by UV irradiation were investigated using the malonaldehyde/gas chromatography assay. At all concentrations (50, 100, or 500 mug/mL) tested, thyme oil mixed with 500 mug/mL clove oil showed over 90% inhibitory effect against malonaldehyde formation. The order of potency of all oils mixed together at 500 mug/mL was thyme/clove leaf (93%) > clove leaf/parsley seed = clove leaf /rose (87%) > thyme/parsley seed (83%) > clove leaf/cinnamon leaf (77%) > thyme/parsley seed (71%) > thyme/cinnamon leaf (7%). In comparison, the inhibitory activities of 500 microg/mL of BHT or alpha-tocopheroltoward malonaldehyde formation were 85% and 76%, respectively. Pro-oxidant effects were observed for some mixtures of thyme with cinnamon leaf or rose oils. The potent antioxidant effects resulting from a mixture of thyme and clove leaf oils may be due to the presence of thymol and eugenol.

  2. Activated CD4+ T cells preferentially take up lipid microspheres, but resting cells do not.

    PubMed Central

    Suzuki, K

    1995-01-01

    Lipid microspheres (LM) used as drug carriers increase the effectiveness and reduce the toxicity of incorporated drugs. The present study is designed to determine whether or not activated T lymphocytes, which were the cells chosen first from the 'inflammatory cells', can take up LM in vitro. LM were labelled with a fluorescent probe, DiI (DiI-LM), to examine the kinetics. Flow cytometric analysis demonstrated that in freshly isolated peripheral blood mononuclear cells (PBMC), monocytes principally took up DiI-LM, while lymphocytes and granulocytes did not. When PBMC were stimulated with immobilized anti-CD3 MoAb and IL-2, cells expressing CD3, CD4, CD8 and CD16 incorporated DiI-LM. Purified CD4+ T cells, obtained by positive panning selection, were stimulated with this system. They were CD25, CD71, LFA-1-positive, and also showed an ability to take up DiI-LM, which resting cells did not. The findings were confirmed by flow cytometry and quantitative analysis of DiI. Confocal micrographs showed fluorescent granules from the probe in the cytoplasm of stimulated CD4+ T cells after incubation with DiI-LM. These results suggest that immunomodulatory agents incorporated into LM might selectively regulate the function of CD4+ or CD8+ T cells when these are activated. Images Fig. 4 PMID:7882572

  3. Cigarette smoking, physical activity, and alcohol consumption: relationship to blood lipids and lipoproteins in premenopausal females.

    PubMed

    Stamford, B A; Matter, S; Fell, R D; Sady, S; Cresanta, M K; Papanek, P

    1984-07-01

    A total of 164 premenopausal female subjects were randomly selected for evaluation from a much larger pool of volunteers. The relationships between blood lipid and lipoprotein levels as dependent variables and cigarette smoking, physical activity, and alcohol consumption were determined from partial regression coefficients. A lower HDL-C level (10.1 mg/dL) was seen in smokers v nonsmokers. For each ounce of alcohol consumed, HDL-C level was higher by 2.8 mg/dL, and greater physical activity was associated with a higher HDL-C level of 8.6 mg/dL. An analysis of covariance with covariance adjustments for age and body fat revealed that smokers who regularly exercise or consume alcohol had significantly lower HDL-C levels than nonsmokers with similar habits. Subjects who both exercise and consume alcohol demonstrated higher HDL-C levels than those who indulge in one or the other separately. Results suggest that cigarette smoking may attenuate the effects of chronic exercise or alcohol consumption, or of both, to raise HDL-C levels. Also, chronic exercise and alcohol consumption may exert an additive effect, raising HDL-C level.

  4. Production of hybrid lipid-based particles loaded with inorganic nanoparticles and active compounds for prolonged topical release.

    PubMed

    García-González, C A; Sampaio da Sousa, A R; Argemí, A; López Periago, A; Saurina, J; Duarte, C M M; Domingo, C

    2009-12-01

    The production of particulate hybrid carriers containing a glyceryl monostearate (Lumulse GMS-K), a waxy triglyceride (Cutina HR), silanized TiO(2) and caffeine were investigated with the aim of producing sunscreens with UV-radiation protection properties. Particles were obtained using the supercritical PGSS (Particles from Gas Saturated Solutions) technique. This method takes advantages of the lower melting temperatures of the lipids obtained from the dissolution of CO(2) in the bulk mixture. Experiments were performed at 13 MPa and 345 K, according to previous melting point measurements. Blends containing Lumulse GMS-K and Cutina HR lipids (50 wt%) were loaded with silanized TiO(2) and caffeine in percentile proportions of 6 and 4 wt%, respectively. The particles produced were characterized using several analytical techniques as follows: system crystallinity was checked by X-ray diffraction and differential scanning calorimetry, thermal stability by thermogravimetric analysis, and morphology by scanning and transmission electron microscopy. Further, the UV-shielding ability of TiO(2) after its dispersion in the lipidic matrix was assessed by solid UV-vis spectroscopy. Preliminary results indicated that caffeine-loaded solid lipid particles presented a two-step dissolution profile, with an initial burst of 60 wt% of the loaded active agent. Lipid blends loaded with TiO(2) and caffeine encompassed the UV-filter behavior of TiO(2) and the photoaging prevention properties of caffeine.

  5. Lipid droplets in activated mast cells - a significant source of triglyceride-derived arachidonic acid for eicosanoid production.

    PubMed

    Dichlberger, Andrea; Schlager, Stefanie; Kovanen, Petri T; Schneider, Wolfgang J

    2016-08-15

    Mast cells are potent effectors of immune reactions and key players in various inflammatory diseases such as atherosclerosis, asthma, and rheumatoid arthritis. The cellular defense response of mast cells represents a unique and powerful system, where external signals can trigger cell activation resulting in a stimulus-specific and highly coordinated release of a plethora of bioactive mediators. The arsenal of mediators encompasses preformed molecules stored in cytoplasmic secretory granules, as well as newly synthesized proteinaceous and lipid mediators. The release of mediators occurs in strict chronological order and requires proper coordination between the endomembrane system and various enzymatic machineries. For the generation of lipid mediators, cytoplasmic lipid droplets have been shown to function as a major intracellular pool of arachidonic acid, the precursor for eicosanoid biosynthesis. Recent studies have revealed that not only phospholipids in mast cell membranes, but also triglycerides in mast cell lipid droplets are a substrate source for eicosanoid formation. The present review summarizes current knowledge about mast cell lipid droplet biology, and discusses expansions and challenges of traditional mechanistic models for eicosanoid production.

  6. Effects of Iron Overload on the Activity of Na,K-ATPase and Lipid Profile of the Human Erythrocyte Membrane.

    PubMed

    Sousa, Leilismara; Garcia, Israel J P; Costa, Tamara G F; Silva, Lilian N D; Renó, Cristiane O; Oliveira, Eneida S; Tilelli, Cristiane Q; Santos, Luciana L; Cortes, Vanessa F; Santos, Herica L; Barbosa, Leandro A

    2015-01-01

    Iron is an essential chemical element for human life. However, in some pathological conditions, such as hereditary hemochromatosis type 1 (HH1), iron overload induces the production of reactive oxygen species that may lead to lipid peroxidation and a change in the plasma-membrane lipid profile. In this study, we investigated whether iron overload interferes with the Na,K-ATPase activity of the plasma membrane by studying erythrocytes that were obtained from the whole blood of patients suffering from iron overload. Additionally, we treated erythrocytes of normal subjects with 0.8 mM H2O2 and 1 μM FeCl3 for 24 h. We then analyzed the lipid profile, lipid peroxidation and Na,K-ATPase activity of plasma membranes derived from these cells. Iron overload was more frequent in men (87.5%) than in women and was associated with an increase (446%) in lipid peroxidation, as indicated by the amount of the thiobarbituric acid reactive substances (TBARS) and an increase (327%) in the Na,K-ATPase activity in the plasma membrane of erythrocytes. Erythrocytes treated with 1 μM FeCl3 for 24 h showed an increase (132%) in the Na,K-ATPase activity but no change in the TBARS levels. Iron treatment also decreased the cholesterol and phospholipid content of the erythrocyte membranes and similar decreases were observed in iron overload patients. In contrast, erythrocytes treated with 0.8 mM H2O2 for 24 h showed no change in the measured parameters. These results indicate that erythrocytes from patients with iron overload exhibit higher Na,K-ATPase activity compared with normal subjects and that this effect is specifically associated with altered iron levels.

  7. Effects of Iron Overload on the Activity of Na,K-ATPase and Lipid Profile of the Human Erythrocyte Membrane

    PubMed Central

    Sousa, Leilismara; Garcia, Israel J. P.; Costa, Tamara G. F.; Silva, Lilian N. D.; Renó, Cristiane O.; Oliveira, Eneida S.; Tilelli, Cristiane Q.; Santos, Luciana L.; Cortes, Vanessa F.; Santos, Herica L.; Barbosa, Leandro A.

    2015-01-01

    Iron is an essential chemical element for human life. However, in some pathological conditions, such as hereditary hemochromatosis type 1 (HH1), iron overload induces the production of reactive oxygen species that may lead to lipid peroxidation and a change in the plasma-membrane lipid profile. In this study, we investigated whether iron overload interferes with the Na,K-ATPase activity of the plasma membrane by studying erythrocytes that were obtained from the whole blood of patients suffering from iron overload. Additionally, we treated erythrocytes of normal subjects with 0.8 mM H2O2 and 1 μM FeCl3 for 24 h. We then analyzed the lipid profile, lipid peroxidation and Na,K-ATPase activity of plasma membranes derived from these cells. Iron overload was more frequent in men (87.5%) than in women and was associated with an increase (446%) in lipid peroxidation, as indicated by the amount of the thiobarbituric acid reactive substances (TBARS) and an increase (327%) in the Na,K-ATPase activity in the plasma membrane of erythrocytes. Erythrocytes treated with 1 μM FeCl3 for 24 h showed an increase (132%) in the Na,K-ATPase activity but no change in the TBARS levels. Iron treatment also decreased the cholesterol and phospholipid content of the erythrocyte membranes and similar decreases were observed in iron overload patients. In contrast, erythrocytes treated with 0.8 mM H2O2 for 24 h showed no change in the measured parameters. These results indicate that erythrocytes from patients with iron overload exhibit higher Na,K-ATPase activity compared with normal subjects and that this effect is specifically associated with altered iron levels. PMID:26197432

  8. Regulation of Ras Exchange Factors and Cellular Localization of Ras Activation by Lipid Messengers in T Cells

    PubMed Central

    Jun, Jesse E.; Rubio, Ignacio; Roose, Jeroen P.

    2013-01-01

    The Ras-MAPK signaling pathway is highly conserved throughout evolution and is activated downstream of a wide range of receptor stimuli. Ras guanine nucleotide exchange factors (RasGEFs) catalyze GTP loading of Ras and play a pivotal role in regulating receptor-ligand induced Ras activity. In T cells, three families of functionally important RasGEFs are expressed: RasGRF, RasGRP, and Son of Sevenless (SOS)-family GEFs. Early on it was recognized that Ras activation is critical for T cell development and that the RasGEFs play an important role herein. More recent work has revealed that nuances in Ras activation appear to significantly impact T cell development and selection. These nuances include distinct biochemical patterns of analog versus digital Ras activation, differences in cellular localization of Ras activation, and intricate interplays between the RasGEFs during distinct T cell developmental stages as revealed by various new mouse models. In many instances, the exact nature of these nuances in Ras activation or how these may result from fine-tuning of the RasGEFs is not understood. One large group of biomolecules critically involved in the control of RasGEFs functions are lipid second messengers. Multiple, yet distinct lipid products are generated following T cell receptor (TCR) stimulation and bind to different domains in the RasGRP and SOS RasGEFs to facilitate the activation of the membrane-anchored Ras GTPases. In this review we highlight how different lipid-based elements are generated by various enzymes downstream of the TCR and other receptors and how these dynamic and interrelated lipid products may fine-tune Ras activation by RasGEFs in developing T cells. PMID:24027568

  9. Effects of alginate on frozen-thawed boar spermatozoa quality, lipid peroxidation and antioxidant enzymes activities.

    PubMed

    Hu, Jinghua; Geng, Guoxia; Li, Qingwang; Sun, Xiuzhu; Cao, Hualin; Liu, Yawei

    2014-06-30

    Although alginate was reported to play an important role as free radical scavengers in vitro and could be used as sources of natural antioxidants, there was no study about the cryoprotective effects of alginate on boar spermatozoa freezing. The objective of this research was to evaluate the effects of different concentrations of alginate added to the freezing extenders on boar spermatozoa motility, plasma membrane integrity, acrosomal integrity, mitochondrial activities, lipid peroxidation and antioxidative enzymes activities (SOD and GSH-Px) after thawing. Alginate was added to the TCG extender to yield six different final concentrations: 0, 0.2, 0.4, 0.6, 0.8, and 1.0mg/mL. The semen extender supplemented with various doses of alginate increased (P<0.05) total motility. The spermatozoa plasma membrane integrity and mitochondrial activity were improved at four different concentrations: 0.4, 0.6, 0.8, 1.0mg/mL. The addition of alginate also provided significantly positive effect on post-thaw boar spermatozoa acrosomal integrity at concentrations of 0.6, 0.8, 1.0mg/mL, compared with that of the control (P<0.05). The freezing extenders with the presence of alginate led to higher SOD and GSH-Px activities and lower MDA levels, in comparison to the control (P<0.05). In summary, alginate exhibited a dose-related response on frozen-thawed boar spermatozoa motility, functional integrity and antioxidative capacity at appropriate concentrations. Therefore alginate could be employed as an effective cryoprotectant in boar spermatozoa cryopreservation.

  10. Lipid phosphatase SHIP2 functions as oncogene in colorectal cancer by regulating PKB activation

    PubMed Central

    Hoekstra, Elmer; Das, Asha M.; Willemsen, Marcella; Swets, Marloes; Kuppen, Peter J.K.; van der Woude, Christien J.; Bruno, Marco J.; Shah, Jigisha P.; Hagen, Timo L.M. ten; Chisholm, John D.; Kerr, William G.; Peppelenbosch, Maikel P.; Fuhler, Gwenny M.

    2016-01-01

    Colorectal cancer (CRC) is the second most common cause of cancer-related death, encouraging the search for novel therapeutic targets affecting tumor cell proliferation and migration. These cellular processes are under tight control of two opposing groups of enzymes; kinases and phosphatases. Aberrant activity of kinases is observed in many forms of cancer and as phosphatases counteract such “oncogenic” kinases, it is generally assumed that phosphatases function as tumor suppressors. However, emerging evidence suggests that the lipid phosphatase SH2-domain-containing 5 inositol phosphatase (SHIP2), encoded by the INPPL1 gene, may act as an oncogene. Just like the well-known tumor suppressor gene Phosphatase and Tensin Homolog (PTEN) it hydrolyses phosphatidylinositol (3,4,5) triphosphate (PI(3,4,5)P3). However, unlike PTEN, the reaction product is PI(3,4)P2, which is required for full activation of the downstream protein kinase B (PKB/Akt), suggesting that SHIP2, in contrast to PTEN, could have a tumor initiating role through PKB activation. In this work, we investigated the role of SHIP2 in colorectal cancer. We found that SHIP2 and INPPL1 expression is increased in colorectal cancer tissue in comparison to adjacent normal tissue, and this is correlated with decreased patient survival. Moreover, SHIP2 is more active in colorectal cancer tissue, suggesting that SHIP2 can induce oncogenesis in colonic epithelial cells. Furthermore, in vitro experiments performed on colorectal cancer cell lines shows an oncogenic role for SHIP2, by enhancing chemoresistance, cell migration, and cell invasion. Together, these data indicate that SHIP2 expression contributes to the malignant potential of colorectal cancer, providing a possible target in the fight against this devastating disease. PMID:27716613

  11. Effect of Repeatedly Heated Palm Olein on Blood Pressure—Regulating Enzymes Activity and Lipid Peroxidation in Rats

    PubMed Central

    Xin-Fang, Leong; Jumat, Salimon; Mohd Rais, Mustafa; Kamsiah, Jaarin

    2012-01-01

    Background: Oxidative stress is associated with the pathogenesis of cardiovascular diseases. The process of deep-fat frying in dietary cooking oil plays a role in the generation of free radicals. In this study, palm olein heated to 180 °C was tested for its effect on the activity of blood pressure–regulating enzymes and lipid peroxidation. Methods: Forty-two adult male Sprague-Dawley rats were equally assigned into 6 groups.The first group was fed with normal rat chow as the control group, and the subsequent groups were fed with rat chow fortified with 15% weight/weight of the following: fresh palm olein, palm olein heated once, palm olein heated twice, palm olein heated 5 times, or palm olein heated 10 times. The duration of feeding was 6 months. Fatty acid analyses of oil were performed using gas chromatography. Peroxide values were determined using standard titration. Plasma was collected for biochemical analyses. Results: Repeatedly heated palm olein increased the levels of peroxide, angiotensin-converting enzyme, and lipid peroxidation as well as reduced the level of heme oxygenase. Fresh palm olein and palm olein heated once had lesser effects on lipid peroxidation and a better effect on the activity of blood pressure–regulating enzymes than repeatedly heated palm olein. Conclusion: Repeatedly heated palm olein may negatively affect the activity of blood pressure–regulating enzymes and increase lipid peroxidation. PMID:22977371

  12. The influence of the long chain fatty acid on the antagonistic activities of Rhizobium sin-1 lipid A

    PubMed Central

    Zhang, Yanghui; Wolfert, Margreet A.; Boons, Geert-Jan

    2007-01-01

    The lipid A from nitrogen-fixing bacterial species R. sin-1 is structurally unusual due to lack of phosphates and the presence of a 2-aminogluconolactone and a very long chain fatty acid, 27-hydroxyoctacosanoic acid (27OHC28:0), moiety. This structurally unusual lipid A can antagonize TNF-α production by human monocytes induced by E. coli LPS. To establish the relevance of the unusual long chain 27-hydroxyoctacosanoic acid for antagonistic properties, a highly convergent strategy for the synthesis of several derivatives of the lipid A of Rhizobium sin-1 has been developed. Compound 1 is a natural R. sin-1 lipid A having a 27-hydroxyoctacosanoic acid at C-2′, compound 2 contains an octacosanoic acid moiety at this position, and compound 3 is modified by a short chain tetradecanoic acid. Cellular activation studies with a human monocytic cell line have shown that the octacosanoic acid is important for optimal antagonistic properties. The hydroxyl of the natural 27-hydroxyoctacosanoic moiety does, however, not account for inhibitory activity. The resulting structure activity relationships are important for the design of compounds for the treatment of septic shock. PMID:17513113

  13. Acclimation to salt modifies the activation of several osmotic stress-activated lipid signalling pathways in Chlamydomonas.

    PubMed

    Meijer, Harold J G; van Himbergen, John A J; Musgrave, Alan; Munnik, Teun

    2017-03-01

    Osmotic stress rapidly activates several phospholipid signalling pathways in the unicellular alga Chlamydomonas. In this report, we have studied the effects of salt-acclimation on growth and phospholipid signalling. Growing cells on media containing 100 mM NaCl increased their salt-tolerance but did not affect the overall phospholipid content, except that levels of phosphatidylinositol phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] were reduced by one-third. When these NaCl-acclimated cells were treated with increasing concentrations of salt, the same lipid signalling pathways as in non-acclimated cells were activated. This was witnessed as increases in phosphatidic acid (PA), lyso-phosphatidic acid (L-PA), diacylglycerol pyrophosphate (DGPP), PI(4,5)P2 and its isomer PI(3,5)P2. However, all dose-dependent responses were shifted to higher osmotic-stress levels, and the responses were lower than in non-acclimated cells. When NaCl-acclimated cells were treated with other osmotica, such as KCl and sucrose, the same effects were found, illustrating that they were due to hyperosmotic rather than hyperionic acclimation. The results indicate that acclimation to moderate salt stress modifies stress perception and the activation of several downstream pathways.

  14. Transcellular activation of platelets and endothelial cells by bioactive lipids in platelet microparticles.

    PubMed Central

    Barry, O. P.; Pratico, D.; Lawson, J. A.; FitzGerald, G. A.

    1997-01-01

    , which it may then use to synthesize PGI2. Both PGE2 and iloprost, a stable PGI2 analog, evoke human umbilical vein endothelial cell COX-2 expression, albeit with kinetics that differ from the response to platelet microparticles. These studies indicate a novel mechanism of transcellular lipid metabolism whereby platelet activation may be amplified or modulated by concentrated delivery of arachidonic acid to adjacent platelets and endothelial cells. PMID:9151784

  15. LINGO-1 regulates oligodendrocyte differentiation by inhibiting ErbB2 translocation and activation in lipid rafts.

    PubMed

    Lee, Xinhua; Shao, Zhaohui; Sheng, Guoqing; Pepinsky, Blake; Mi, Sha

    2014-05-01

    Oligodendrocyte differentiation is negatively regulated by LINGO-1 and positively regulated by the ErbB2 receptor tyrosine kinase. In wild-type oligodendrocytes, inhibition of ErbB2 blocks differentiation, whereas activation of ErbB2 promotes differentiation. In LINGO-1(-/-) oligodendrocytes, inhibition of ErbB2 blocks oligodendrocyte differentiation; whereas activation of ErbB2 does not enhance differentiation. Biological and biochemical evidence showing that LINGO-1 can directly bind to ErbB2, block ErbB2 translocation into lipid rafts, and inhibit its phosphorylation for activation. The study demonstrates a novel regulatory mechanism of ErbB2 function whereby LINGO-1 suppresses oligodendrocyte differentiation by inhibiting ErbB2 translocation and activation in lipid rafts.

  16. Recombinant cannabinoid type 2 receptor in liposome model activates g protein in response to anionic lipid constituents.

    PubMed

    Kimura, Tomohiro; Yeliseev, Alexei A; Vukoti, Krishna; Rhodes, Steven D; Cheng, Kejun; Rice, Kenner C; Gawrisch, Klaus

    2012-02-03

    Human cannabinoid type 2 (CB(2)) receptor expressed in Escherichia coli was purified and successfully reconstituted in the functional form into lipid bilayers composed of POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS), and cholesteryl hemisuccinate (CHS). Reconstitution was performed by detergent removal from the protein/lipid/detergent mixed micelles either on an adsorbent column, or by rapid dilution to below the critical micelle concentration of detergent followed by removal of detergent monomers on a concentrator. Proteoliposomes prepared at a protein/phospholipid/CHS molar ratio of 1/620-650/210-220 are free of detergent as shown by (1)H NMR, have a homogeneous protein/lipid ratio shown by isopycnic gradient ultracentrifugation, and are small in size with a mean diameter of 150-200 nm as measured by dynamic light scattering. Functional integrity of the reconstituted receptor was confirmed by quantitative binding of (2)H-labeled agonist CP-55,940-d(6) measured by (2)H magic angle spinning NMR, as well as by activation of G protein. The efficiency of G protein activation by agonist-bound CB(2) receptor was affected by negative electric surface potentials of proteoliposomes controlled by the content of anionic CHS or POPS. The activation was highest at an anionic lipid content of about 50 mol %. There was no correlation between the efficiency of G protein activation and an increase of hydrocarbon chain order induced by CHS or cholesterol. The results suggest the importance of anionic lipids in regulating signal transduction by CB(2) receptor and other class A GPCR. The successful reconstitution of milligram quantities of pure, functional CB(2) receptor enables a wide variety of structural studies.

  17. Involvement of active oxygen in lipid peroxide radical reaction of epidermal homogenate following ultraviolet light exposure

    SciTech Connect

    Nishi, J.; Ogura, R.; Sugiyama, M.; Hidaka, T.; Kohno, M. )

    1991-07-01

    To elucidate the radical mechanism of lipid peroxidation induced by ultraviolet light (UV) irradiation, an electron spin resonance (ESR) study was made on epidermal homogenate prepared from albino rat skin. The exposure of the homogenate to UV light resulted in an increase in lipid peroxide content, which was proportional to the time of UV exposure. Using ESR spin trapping (dimethyl-1-pyrroline-N-oxide, DMPO), the DMPO spin adduct spectrum of lipid radicals (L.) was measured following UV exposure (DMPO-L.:aN = 15.5 G, aH = 22.7 G), as was the spectrum of DMPO-hydroxyl radical (DMPO-OH, aN = aH = 15.5 G). In the presence of superoxide dismutase, the DMPO spin adduct spectrum of lipid radicals was found to be reduced remarkably. Therefore, it was shown that the generation of the lipid radicals partially involves superoxide anion radicals, in addition to hydroxyl radicals. In the ESR free-radical experiment, an ESR signal appeared at g = 2.0064 when the ESR tube filled with homogenate was exposed to UV light at -150 degrees C. The temperature-dependent change in the ESR free radical signal of homogenate exposed to UV light was observed at temperatures varying from -150 degrees C to room temperature. By using degassed samples, it was confirmed that oxygen is involved in the formation of the lipid peroxide radicals (LOO.) from the lipid radicals (L.).

  18. The activation loop of PIP5K functions as a membrane sensor essential for lipid substrate processing

    PubMed Central

    Liu, Aizhuo; Sui, Dexin; Wu, Dianqing; Hu, Jian

    2016-01-01

    Phosphatidylinositol 4-phosphate 5-kinase (PIP5K), a representative member of the phosphatidylinositol phosphate kinase (PIPK) family, is a major enzyme that biosynthesizes the signaling molecule PI(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) in eukaryotic cells. The stringent specificity toward lipid substrates and the high sensitivity to the membrane environment strongly suggest a membrane-sensing mechanism, but the underlying structural basis is still largely unknown. We present a nuclear magnetic resonance (NMR) study on a peptide commensurate with a PIP5K’s activation loop, which has been reported to be a determinant of lipid substrate specificity and subcellular localization of PIP5K. Although the activation loop is severely disordered in the crystal structure of PIP5K, the NMR experiments showed that the largely unstructured peptide folded into an amphipathic helix upon its association with the 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) micellar surface. Systematic mutagenesis and functional assays further demonstrated the crucial roles of the amphipathic helix and its hydrophobic surface in kinase activity and membrane-sensing function, supporting a working model in which the activation loop is a critical structural module conferring a membrane-sensing mechanism on PIP5K. The activation loop, surprisingly functioning as a membrane sensor, represents a new paradigm of kinase regulation by the activation loop through protein-membrane interaction, which also lays a foundation on the regulation of PIP5K (and other PIPKs) by membrane lipids for future studies. PMID:28138522

  19. Inhibition of RPE65 Retinol Isomerase Activity by Inhibitors of Lipid Metabolism*

    PubMed Central

    Eroglu, Abdulkerim; Gentleman, Susan; Poliakov, Eugenia; Redmond, T. Michael

    2016-01-01

    RPE65 is the isomerase catalyzing conversion of all-trans-retinyl ester (atRE) into 11-cis-retinol in the retinal visual cycle. Crystal structures of RPE65 and site-directed mutagenesis reveal aspects of its catalytic mechanism, especially retinyl moiety isomerization, but other aspects remain to be determined. To investigate potential interactions between RPE65 and lipid metabolism enzymes, HEK293-F cells were transfected with expression vectors for visual cycle proteins and co-transfected with either fatty acyl:CoA ligases (ACSLs) 1, 3, or 6 or the SLC27A family fatty acyl-CoA synthase FATP2/SLCA27A2 to test their effect on isomerase activity. These experiments showed that RPE65 activity was reduced by co-expression of ACSLs or FATP2. Surprisingly, however, in attempting to relieve the ACSL-mediated inhibition, we discovered that triacsin C, an inhibitor of ACSLs, also potently inhibited RPE65 isomerase activity in cellulo. We found triacsin C to be a competitive inhibitor of RPE65 (IC50 = 500 nm). We confirmed that triacsin C competes directly with atRE by incubating membranes prepared from chicken RPE65-transfected cells with liposomes containing 0–1 μm atRE. Other inhibitors of ACSLs had modest inhibitory effects compared with triascin C. In conclusion, we have identified an inhibitor of ACSLs as a potent inhibitor of RPE65 that competes with the atRE substrate of RPE65 for binding. Triacsin C, with an alkenyl chain resembling but not identical to either acyl or retinyl chains, may compete with binding of the acyl moiety of atRE via the alkenyl moiety. Its inhibitory effect, however, may reside in its nitrosohydrazone/triazene moiety. PMID:26719343

  20. Association between Physical Activity and Metabolic Risk Factors in Adolescents: Tehran Lipid and Glucose Study

    PubMed Central

    Fam, Bita; Amouzegar, Atieh; Arzhan, Soraya; Ghanbariyan, Arash; Delshad, Maryam; Hosseinpanah, Farhad; Azizi, Fereidoun

    2013-01-01

    Background: Physical activity (PA) is associated with the metabolic syndrome (MetS) and its components. This study aimed to examine the association between PA and MetS and its components among normal weight and overweight/obese adolescent in Tehran Lipid and Glucose Study (TLGS). Methods: This cross-sectional study includes 777 adolescents, aged 12-18 years, who were selected by multi-stage random cluster sampling from among TLGS participants. Subjects were classified as normal weight and overweight/obese based on the age- and sex-specific standardized percentile curves of BMI for Iranian population. Levels of PA were assessed using a standardized and modifiable activity questionnaire (MAQ), and categorized into tertiles. MetS was defined according to the Cook's criteria. Results: Prevalence of the MetS was higher in overweight/obese than normal group (35% vs. 3%; P: 0.02). Normal groups were more physically active (50% vs. 44%); however, difference was not significant. There was a significant association between the light PA and risk of lower level of HDL-C before and after adjustment, in normal weight group (OR: 1.61, CI 95%: 1.11, 2.35; OR: 1.65, CI 95%: 1.12, 2.44, respectively). The overweight/obese group with light and moderate PA had a higher risk of having abdominal obesity than those with vigorous PA, only after adjustment for determined covariates (OR: 1.11, CI 95%: 1.07, 1.21; OR: 1.06, CI 95%: 1.01, 1.08, respectively); the association between MetS and PA was not significant. Conclusions: The results of this study confirm the association between PA and some individual components of MetS such as waist and HDL-C. PMID:24130941

  1. Activation of lecithin cholesterol acyltransferase by human apolipoprotein E in discoidal complexes with lipids.

    PubMed

    Zorich, N; Jonas, A; Pownall, H J

    1985-07-25

    In a continued investigation of lecithin cholesterol acyltransferase reaction with micellar discoidal complexes of phosphatidylcholine, cholesterol, and various water soluble apolipoproteins, we prepared complexes containing human apo-E by the cholate dialysis method. These complexes were systematically compared to apo-A-I complexes synthesized under the same reaction conditions. Apo-E complexes (134 A in diameter) were slightly larger than apo-A-I complexes (110 A) but were very similar in terms of their protein and lipid content (2.4:0.10:1.0, egg phosphatidylcholine/cholesterol/apolipoprotein, w/w) and in the percentage of apolipoprotein in alpha-helical structure (72-74%). Concentration and temperature-dependence experiments on the velocity of the lecithin cholesterol acyltransferase reaction revealed differences in apparent Km values and small differences in apparent Vmax but very similar activation energies (18-20 kcal/mol). These observations suggest that differences in lecithin cholesterol acyltransferase activation by apo-A-I and apo-E are primarily a result of different affinities of the enzyme for the particles but that the rate-limiting step of the reaction is comparable for both complexes. Apo-E was found to be 18% as effective as apo-A-I in activating purified human lecithin cholesterol acyltransferase. Addition of free apo-A-I to apo-E complexes resulted in the exchange of bound for free apolipoprotein causing a slight increase in the reactivity with the enzyme when the incubation mixture was assayed. When the unbound apolipoproteins were removed by ultracentrifugation reisolated complexes containing both apo-E and apo-A-I demonstrated an even greater increase in reactivity with the enzyme.

  2. The Lipid Portion of Activated Platelet-Rich Plasma Significantly Contributes to Its Wound Healing Properties

    PubMed Central

    Hoeferlin, Lauren Alexis; Huynh, Quoc K.; Mietla, Jennifer A.; Sell, Scott A.; Tucker, Jason; Chalfant, Charles Edward; Wijesinghe, Dayanjan Shanaka

    2015-01-01

    Objective: Platelet-rich plasma (PRP) is a popular choice for the treatment of chronic wounds. Current dogma attributes these healing properties to the peptide growth factors of PRP. However, PRP is also rich in bioactive lipids whose contribution to healing has not been characterized and warrants investigation due to the protease-rich environment of chronic wounds. Approach: The lipid fraction of PRP was tested with respect to proliferation and migration of primary adult human dermal fibroblasts (HDFa)±exposure to chronic wound fluid (CWF). This fraction was also characterized via LC-MS/MS for bioactive lipids. A synthetic formulation of the bioactive lipid composition was developed and tested for the ability to overcome proliferative growth arrest induced by CWF. Results: The data demonstrate the ability of the lipid fraction of PRP to significantly enhance the migration and proliferation of HDFa, and to overcome the proliferative growth arrest induced by CWF. Furthermore, the synthetic lipid formulation generated following characterization of the PRP lipidome demonstrated a similar ability to overcome proliferative arrest of HDFa in the presence of CWF. Innovation: For the first time, we demonstrate the relevance of the lipid fraction of PRP toward the biology of wound healing. These studies open the possibility of altering the lipid profile of PRP via diet or exogenous pathway manipulation to obtain a better healing outcome. Conclusion: The lipid fraction of PRP is under investigated and yet relevant component in wound healing. The current study demonstrates the relevance of this fraction in wound healing by PRP. PMID:25713752

  3. New Role for Kruppel-like Factor 14 as a Transcriptional Activator Involved in the Generation of Signaling Lipids*

    PubMed Central

    de Assuncao, Thiago M.; Lomberk, Gwen; Cao, Sheng; Yaqoob, Usman; Mathison, Angela; Simonetto, Douglas A.; Huebert, Robert C.; Urrutia, Raul A.; Shah, Vijay H.

    2014-01-01

    Sphingosine kinase 1 (SK1) is an FGF-inducible gene responsible for generation of sphingosine-1-phosphate, a critical lipid signaling molecule implicated in diverse endothelial cell functions. In this study, we identified SK1 as a target of the canonical FGF2/FGF receptor 1 activation pathway in endothelial cells and sought to identify novel transcriptional pathways that mediate lipid signaling. Studies using the 1.9-kb SK1 promoter and deletion mutants revealed that basal and FGF2-stimulated promoter activity occurred through two GC-rich regions located within 633 bp of the transcription start site. Screening for GC-rich binding transcription factors that could activate this site demonstrated that KLF14, a gene implicated in obesity and the metabolic syndrome, binds to this region. Congruently, overexpression of KLF14 increased basal and FGF2-stimulated SK1 promoter activity by 3-fold, and this effect was abrogated after mutation of the GC-rich sites. In addition, KLF14 siRNA transfection decreased SK1 mRNA and protein levels by 3-fold. Congruently, SK1 mRNA and protein levels were decreased in livers from KLF14 knock-out mice. Combined, luciferase, gel shift, and chromatin immunoprecipitation assays showed that KLF14 couples to p300 to increase the levels of histone marks associated with transcriptional activation (H4K8ac and H3K14ac), while decreasing repressive marks (H3K9me3 and H3K27me3). Collectively, the results demonstrate a novel mechanism whereby SK1 lipid signaling is regulated by epigenetic modifications conferred by KLF14 and p300. Thus, this is the first description of the activity and mechanisms underlying the function of KLF14 as an activator protein and novel regulator of lipid signaling. PMID:24759103

  4. Tuning a cellular lipid kinase activity adapts hepatitis C virus to replication in cell culture.

    PubMed

    Harak, Christian; Meyrath, Max; Romero-Brey, Inés; Schenk, Christian; Gondeau, Claire; Schult, Philipp; Esser-Nobis, Katharina; Saeed, Mohsan; Neddermann, Petra; Schnitzler, Paul; Gotthardt, Daniel; Perez-Del-Pulgar, Sofia; Neumann-Haefelin, Christoph; Thimme, Robert; Meuleman, Philip; Vondran, Florian W R; Francesco, Raffaele De; Rice, Charles M; Bartenschlager, Ralf; Lohmann, Volker

    2016-12-19

    With a single exception, all isolates of hepatitis C virus (HCV) require adaptive mutations to replicate efficiently in cell culture. Here, we show that a major class of adaptive mutations regulates the activity of a cellular lipid kinase, phosphatidylinositol 4-kinase IIIα (PI4KA). HCV needs to stimulate PI4KA to create a permissive phosphatidylinositol 4-phosphate-enriched membrane microenvironment in the liver and in primary human hepatocytes (PHHs). In contrast, in Huh7 hepatoma cells, the virus must acquire loss-of-function mutations that prevent PI4KA overactivation. This adaptive mechanism is necessitated by increased PI4KA levels in Huh7 cells compared with PHHs, and is conserved across HCV genotypes. PI4KA-specific inhibitors promote replication of unadapted viral isolates and allow efficient replication of patient-derived virus in cell culture. In summary, this study has uncovered a long-sought mechanism of HCV cell-culture adaptation and demonstrates how a virus can adapt to changes in a cellular environment associated with tumorigenesis.

  5. α-Tocopherol succinate improves encapsulation and anticancer activity of doxorubicin loaded in solid lipid nanoparticles.

    PubMed

    Oliveira, Mariana S; Mussi, Samuel V; Gomes, Dawidson A; Yoshida, Maria Irene; Frezard, Frederic; Carregal, Virgínia M; Ferreira, Lucas A M

    2016-04-01

    This work aimed to develop solid lipid nanoparticles (SLN) co-loaded with doxorubicin and α-tocopheryl succinate (TS), a succinic acid ester of α-tocopherol that exhibits anticancer actions, evaluating the influence of TS on drug encapsulation efficiency. The SLN were characterized for size, zeta potential, entrapment efficiency (EE), and drug release. Studies of in vitro anticancer activity were also conducted. The EE was significantly improved from 30 ± 1% to 96 ± 2% for SLN without and with TS at 0.4%, respectively. In contrast, a reduction in particle size from 298 ± 1 to 79 ± 1 nm was observed for SLN without and with TS respectively. The doxorubicin release data show that SLN provide a controlled drug release. The in vitro studies showed higher cytotoxicity for doxorubicin-TS-loaded SLN than for free doxorubicin in breast cancer cells. These findings suggest that TS-doxorubicin-loaded SLN is a promising alternative for the treatment of cancer.

  6. Lipid infusion lowers sympathetic nervous activity and leads to increased β-cell responsiveness to glucose

    PubMed Central

    Magnan, Christophe; Collins, Stephan; Berthault, Marie-France; Kassis, Nadim; Vincent, Mylène; Gilbert, Marc; Pénicaud, Luc; Ktorza, Alain; Assimacopoulos-Jeannet, Françoise

    1999-01-01

    We investigated the possible involvement of the autonomic nervous system in the effect of a long-term elevation of plasma free fatty acid (FFA) concentration on glucose-induced insulin secretion (GIIS) in rats. Rats were infused with an emulsion of triglycerides (Intralipid) for 48 hours (IL rats). This resulted in a twofold increase in plasma FFA concentration. At the end of infusion, GIIS as reflected in the insulinogenic index (ΔI/ΔG) was 2.5-fold greater in IL rats compared with control saline-infused rats. The ratio of sympathetic to parasympathetic nervous activities was sharply decreased in IL rats relative to controls. GIIS was studied in the presence of increasing amounts of α- and β-adrenoreceptor agonists and antagonists. The lowest concentrations of the α2A-adrenoreceptor agonist oxymetazoline, which were ineffective in control rats, reduced GIIS in IL rats. At the dose of 0.3 pmol/kg, GIIS became similar in IL and control rats. The use of β-adrenoreceptor agonist (isoproterenol) or antagonist (propranolol) did not result in a significant alteration in GIIS in both groups. GIIS remained as high in IL vagotomized rats as in intact IL rats, indicating that changes in parasympathetic tone were of minor importance. Altogether, the data show that lipid infusion provokes β-cell hyperresponsiveness in vivo, at least in part through changes in α2-adrenergic innervation. PMID:9927503

  7. Preparation, characterisation and antibacterial activity of a florfenicol-loaded solid lipid nanoparticle suspension.

    PubMed

    Wang, Ting; Chen, Xiaojin; Lu, Mengmeng; Li, Xihe; Zhou, WenZhong

    2015-12-01

    A florfenicol-loaded solid lipid nanoparticle (FFC-SLN) suspension was prepared by hot homogenisation and ultrasonic technique. The suspension was characterised for its release profile, stability, toxicity, and the physicochemical properties of the nanoparticles. Antibacterial activity of the suspension was evaluated in vitro and in vivo. The results showed that the mean diameter, polydispersity index and zeta potential of the nanoparticles were 253 ± 3 nm, 0.409 ± 0.022 and 47.5 ± 0.21 mV, respectively. In vitro release profile showed the FFC-SLN suspension had sustained release effect. The minimum inhibition concentration values of the FFC-SLN suspension were 6 and 3 µg/mL against Staphylococcus aureus and Escherichia coli respectively, compared with 3.5 and 2 µg/mL of native florfenicol. The suspension was relatively stable at 4°C and less stable at room temperature during 9 months storage. Although the nanoparticle carriers exhibited cytotoxicity in cell cultures, the LD50 of the lyophilised dry power of the suspension was higher than 5 g/kg body weight. Mortality protection against E. coli lethal infection in mice showed that the nanoparticle suspension had much better efficacy (6/10) than native drug (1/10). These results indicate that FFC-SLN suspension could be a promising formulation in veterinary medicine.

  8. Modulation Effect of Peroxisome Proliferator-Activated Receptor Agonists on Lipid Droplet Proteins in Liver

    PubMed Central

    Zhu, Yun-Xia; Zhang, Ming-Liang; Zhong, Yuan; Wang, Chen; Jia, Wei-Ping

    2016-01-01

    Peroxisome proliferator-activated receptor (PPAR) agonists are used for treating hyperglycemia and type 2 diabetes. However, the mechanism of action of these agonists is still under investigation. The lipid droplet-associated proteins FSP27/CIDEC and LSDP5, regulated directly by PPARγ and PPARα, are associated with hepatic steatosis and insulin sensitivity. Here, we evaluated the expression levels of FSP27/CIDEC and LSDP5 and the regulation of these proteins by consumption of a high-fat diet (HFD) or administration of PPAR agonists. Mice with diet-induced obesity were treated with the PPARγ or PPARα agonist, pioglitazone or fenofibrate, respectively. Liver tissues from db/db diabetic mice and human were also collected. Interestingly, FSP27/CIEDC was expressed in mouse and human livers and was upregulated in obese C57BL/6J mice. Fenofibrate treatment decreased hepatic triglyceride (TG) content and FSP27/CIDEC protein expression in mice fed an HFD diet. In mice, LSDP5 was not detected, even in the context of insulin resistance or treatment with PPAR agonists. However, LSDP5 was highly expressed in humans, with elevated expression observed in the fatty liver. We concluded that fenofibrate greatly decreased hepatic TG content and FSP27/CIDEC protein expression in mice fed an HFD, suggesting a potential regulatory role for fenofibrate in the amelioration of hepatic steatosis. PMID:26770990

  9. A keratin scaffold regulates epidermal barrier formation, mitochondrial lipid composition, and activity

    PubMed Central

    Kumar, Vinod; Bouameur, Jamal-Eddine; Bär, Janina; Rice, Robert H.; Hornig-Do, Hue-Tran; Roop, Dennis R.; Schwarz, Nicole; Brodesser, Susanne; Thiering, Sören; Leube, Rudolf E.; Wiesner, Rudolf J.; Vijayaraj, Preethi; Brazel, Christina B.; Heller, Sandra; Binder, Hans; Löffler-Wirth, Henry; Seibel, Peter

    2015-01-01

    Keratin intermediate filaments (KIFs) protect the epidermis against mechanical force, support strong adhesion, help barrier formation, and regulate growth. The mechanisms by which type I and II keratins contribute to these functions remain incompletely understood. Here, we report that mice lacking all type I or type II keratins display severe barrier defects and fragile skin, leading to perinatal mortality with full penetrance. Comparative proteomics of cornified envelopes (CEs) from prenatal KtyI−/− and KtyII−/−K8 mice demonstrates that absence of KIF causes dysregulation of many CE constituents, including downregulation of desmoglein 1. Despite persistence of loricrin expression and upregulation of many Nrf2 targets, including CE components Sprr2d and Sprr2h, extensive barrier defects persist, identifying keratins as essential CE scaffolds. Furthermore, we show that KIFs control mitochondrial lipid composition and activity in a cell-intrinsic manner. Therefore, our study explains the complexity of keratinopathies accompanied by barrier disorders by linking keratin scaffolds to mitochondria, adhesion, and CE formation. PMID:26644517

  10. Quercetin-nanostructured lipid carriers: characteristics and anti-breast cancer activities in vitro.

    PubMed

    Sun, Ming; Nie, Shufang; Pan, Xuan; Zhang, Ruiwen; Fan, Zhaoyang; Wang, Shu

    2014-01-01

    Quercetin (Q), a common dietary flavonoid, has gained research attention in cancer chemo-prevention, but its low level of aqueous solubility, stability, cellular bioavailability has limited its application. We have synthesized biocompatible and biodegradable Q-nanostructured lipid carriers (Q-NLC) using a novel phase inversion-based process method. The average size of Q-NLC was 32 nm in diameter. Q-NLC had good chemical and physical stability, and showed a sustained release pattern. The encapsulation efficiency and loading capacity of Q-NLC were 95% and 11%, respectively. The aqueous solubility of Q was dramatically improved by at least 1000 folds. The results from Raman spectroscopy, powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) demonstrated that Q presented in NLC as an encapsulated molecule form. As compared to native Q, Q-NLC dramatically increased cytotoxicity in a dose-dependent manner (1-50 μM) and induced apoptosis at 20 μM in MCF-7 and MDA-MB-231 breast cancer cells. The enhanced cytotoxicity and apoptosis were parallel to increased Q uptake by those cancer cells. Void NLC did not change the viability and apoptosis of those cancer cells as compared to phosphate buffered saline. In conclusion, Q-NLC dramatically enhanced the anti-cancer activities of Q, which were associated with enhanced Q solubility and stability, and increased Q content in those cancer cells. Q-NLC have a potential for chemo-preventive use in breast cancer.

  11. Role of Innate Immune Factors in the Adjuvant Activity of Monophosphoryl Lipid A

    PubMed Central

    Martin, Michael; Michalek, Suzanne M.; Katz, Jannet

    2003-01-01

    Monophosphoryl lipid A (MPL) is a nontoxic derivative of lipopolysaccharide (LPS) that exhibits adjuvant properties similar to those of the parent LPS molecule. However, the mechanism by which MPL initiates its immunostimulatory properties remains unclear. Due to the involvement of Toll-like receptors in recognizing and transducing intracellular signals in response to LPS, the aim of the present study was to determine the ability of MPL to utilize the Toll-like receptor 2 (TLR2) and TLR4. We provide evidence that MPL differentially utilizes TLR2 and TLR4 for the induction of tumor necrosis factor alpha, interleukin 10 (IL-10), and IL-12 by purified human monocytes as well as by human peripheral blood mononuclear cells. Assessment of NF-κB activity demonstrated that MPL utilized TLR2 and especially TLR4 for the activation of NF-κB p65 by human monocytes. In addition, stimulation of human monocytes by MPL led to an up-regulation of the costimulatory molecules CD80 and CD86, an effect that could be reduced by pretreatment of cells with a monoclonal antibody to TLR2 or TLR4. Analysis of MPL-induced activation of the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases revealed that MPL utilized both TLR2 and TLR4 for the phosphorylation of ERK1/2, while TLR4 was the predominant receptor involved in the ability of MPL to phosphorylate p38. Moreover, using selective inhibitors for MAP kinase kinase (PD98059) and p38 (SB203580), we show that ERK1/2 exhibited differential effects on production of TNF-α and IL-12 p40 by human monocytes, whereas MPL-induced activation of p38 appeared to be predominantly involved in production of IL-10 and IL-12 p40 by MPL-stimulated monocytes. Taken together, these findings aid in understanding the cellular mechanisms by which MPL induces host cell activation and subsequent adjuvant properties. PMID:12704121

  12. A novel lipid-based nanomicelle of docetaxel: evaluation of antitumor activity and biodistribution

    PubMed Central

    Ma, Mingshu; Hao, Yanli; Liu, Nan; Yin, Zhe; Wang, Lan; Liang, Xingjie; Zhang, Xiaoning

    2012-01-01

    Purpose A lipid-based, nanomicelle-loaded docetaxel (M-DOC) was designed and characterized. Optical imaging was employed to evaluate the pharmacokinetics and antitumor efficacy of docetaxel in vivo. Materials and methods The M-DOC was prepared using the emulsion-diffusion method. Transmission electron microscopy and dynamic light scattering were used to assess the morphology and particle size of the M-DOC. Critical micelle concentrations, their stability under physiological conditions, and their encapsulation efficiency – as measured by high-performance liquid chromatography – were assessed. Pharmacological features were evaluated in two different animal models by comparing M-DOC treatments with docetaxel injections (I-DOC). Bioluminescence imaging was used to assess antitumor activity and docetaxel distribution in vivo, using nude mice injected with luciferase-expressing MDA-MB-231 human breast tumor cells. In addition, animals injected with B16 melanoma cells were used to measure survival time and docetaxel distribution. Results The M-DOC was prepared as round, uniform spheres with an effective diameter of 20.8 nm. The critical micelle concentration of the original emulsion was 0.06%. Satisfactory encapsulation efficiency (87.6% ± 3.0%) and 12-hour stability were achieved. Xenograft results demonstrated that the M-DOC was more effective in inhibiting tumor growth, without significantly changing body weight. Survival was prolonged by 12.6% in the M-DOC group. Tumor growth inhibitory rates in the M-DOC and I-DOC groups were 91.2% and 57.8% in volume and 71.8% and 44.9% in weight, respectively. Optical bioluminescence imaging of tumor growths yielded similar results. Area under the curve(0–6 hour) levels of docetaxel in blood and tumors were significantly higher in the M-DOC group (15.9 ± 3.2 μg/mL−1, 601.1 ± 194.5 μg/g−1) than in the I-DOC group (7.2 ± 1.7 μg/mL−1, 357.8 ± 86.2 μg/g−1). The fluorescent dye 1,1-dioctadecyl-3,3,3,3

  13. Efficacious gene silencing in serum and significant apoptotic activity induction by survivin downregulation mediated by new cationic gemini tocopheryl lipids.

    PubMed

    Kumar, Krishan; Maiti, Bappa; Kondaiah, Paturu; Bhattacharya, Santanu

    2015-02-02

    Nonviral gene delivery offers cationic liposomes as promising instruments for the delivery of double-stranded RNA (ds RNA) molecules for successful sequence-specific gene silencing (RNA interference). The efficient delivery of siRNA (small interfering RNA) to cells while avoiding unexpected side effects is an important prerequisite for the exploitation of the power of this excellent tool. We present here six new tocopherol based cationic gemini lipids, which induce substantial gene knockdown without any obvious cytotoxicity. All the efficient coliposomal formulations derived from each of these geminis and a helper lipid, dioleoylphosphatidylethanolamine (DOPE), were well characterized using physical methods such as atomic force microscopy (AFM) and dynamic light scattering (DLS). Zeta potential measurements were conducted to estimate the surface charge of these formulations. Flow cytometric analysis showed that the optimized coliposomal formulations could transfect anti-GFP siRNA efficiently in three different GFP expressing cell lines, viz., HEK 293T, HeLa, and Caco-2, significantly better than a potent commercial standard Lipofectamine 2000 (L2K) both in the absence and in the presence of serum (FBS). Notably, the knockdown activity of coliposomes of gemini lipids was not affected even in the presence of serum (10% and 50% FBS) while it dropped down for L2K significantly. Observations under a fluorescence microscope, RT-PCR, and Western blot analysis substantiated the flow cytometry results. The efficient cellular entry of labeled siRNA in GFP expressing cells as evidenced from confocal microscopy put forward these gemini lipids among the potent lipidic carriers for siRNA. The efficient transfection capabilities were also profiled in a more relevant fashion while performing siRNA transfections against survivin (an anti-apoptotic protein) which induced substantial apoptosis. Furthermore, the survivin downregulation improved the therapeutic efficacy levels of an

  14. Lipid emulsion enhances cardiac performance after ischemia-reperfusion in isolated hearts from summer-active arctic ground squirrels.

    PubMed

    Salzman, Michele M; Cheng, Qunli; Deklotz, Richard J; Dulai, Gurpreet K; Douglas, Hunter F; Dikalova, Anna E; Weihrauch, Dorothee; Barnes, Brian M; Riess, Matthias L

    2017-03-31

    Hibernating mammals, like the arctic ground squirrel (AGS), exhibit robust resistance to myocardial ischemia/reperfusion (IR) injury. Regulated preference for lipid over glucose to fuel metabolism may play an important role. We tested whether providing lipid in an emulsion protects hearts from summer-active AGS better than hearts from Brown Norway (BN) rats against normothermic IR injury. Langendorff-prepared AGS and BN rat hearts were perfused with Krebs solution containing 7.5 mM glucose with or without 1% Intralipid™. After stabilization and cardioplegia, hearts underwent 45-min global ischemia and 60-min reperfusion. Coronary flow, isovolumetric left ventricular pressure, and mitochondrial redox state were measured continuously; infarct size was measured at the end of the experiment. Glucose-only AGS hearts functioned significantly better on reperfusion than BN rat hearts. Intralipid™ administration resulted in additional functional improvement in AGS compared to glucose-only and BN rat hearts. Infarct size was not different among groups. Even under non-hibernating conditions, AGS hearts performed better after IR than the best-protected rat strain. This, however, appears to strongly depend on metabolic fuel: Intralipid™ led to a significant improvement in return of function in AGS, but not in BN rat hearts, suggesting that year-round endogenous mechanisms are involved in myocardial lipid utilization that contributes to improved cardiac performance, independent of the metabolic rate decrease during hibernation. Comparative lipid analysis revealed four candidates as possible cardioprotective lipid groups. The improved function in Intralipid™-perfused AGS hearts also challenges the current paradigm that increased glucose and decreased lipid metabolism are favorable during myocardial IR.

  15. Association of Vibrio parahaemolyticus thermostable direct hemolysin with lipid rafts is essential for cytotoxicity but not hemolytic activity.

    PubMed

    Matsuda, Shigeaki; Kodama, Toshio; Okada, Natsumi; Okayama, Kanna; Honda, Takeshi; Iida, Tetsuya

    2010-02-01

    Thermostable direct hemolysin (TDH), a major virulence factor of Vibrio parahaemolyticus, induces cytotoxicity in cultured cells. However, the mechanism of TDH's cytotoxic effect including its target molecules on the plasma membrane of eukaryotic cells remains unclear. In this study, we identified the role of lipid rafts, cholesterol- and sphingolipid-enriched microdomains, in TDH cytotoxicity. Treatment of cells with methyl-beta-cyclodextrin (MbetaCD), a raft-disrupting agent, inhibited TDH cytotoxicity. TDH was associated with detergent-resistant membranes (DRMs), and MbetaCD eliminated this association. In contrast, there was no such association between a nontoxic TDH mutant and DRMs. The disruption of lipid rafts neither affected hemolysis nor inhibited Ca(2+) influx into HeLa cells induced by TDH. These findings indicate that the cytotoxicity but not the hemolytic activity of TDH is dependent on lipid rafts. The exogenous and endogenous depletion of cellular sphingomyelin also prevented TDH cytotoxicity, but a direct interaction between TDH and sphingomyelin was not detected with either a lipid overlay assay or a liposome absorption test. Treatment with sphingomyelinase (SMase) at 100 mU/ml disrupted the association of TDH with DRMs but did not affect the localization of lipid raft marker proteins (caveolin-1 and flotillin-1) with DRMs. These results suggest that sphingomyelin is important for the association of TDH with lipid rafts but is not a molecular target of TDH. We hypothesize that TDH may target a certain group of rafts that are sensitive to SMase at a certain concentration, which does not affect other types of rafts.

  16. The neutral lipid composition present in the digestive vacuole of Plasmodium falciparum concentrates heme and mediates β-hematin formation with an unusually low activation energy.

    PubMed

    Hoang, Anh N; Sandlin, Rebecca D; Omar, Aneesa; Egan, Timothy J; Wright, David W

    2010-11-30

    In eukaryotic cells, neutral lipids serve as major energy storage molecules; however, in Plasmodium falciparum, a parasite responsible for causing malaria in humans, neutral lipids may have other functions during the intraerythrocytic stage of the parasite life cycle. Specifically, experimental data suggest that neutral lipid structures behave as a catalyst for the crystallization of hemozoin, a detoxification byproduct of several blood-feeding organisms, including malaria parasites. Synthetic neutral lipid droplets (SNLDs) were produced by depositing a lipid blend solution comprised of mono- and diglycerides onto an aqueous surface. These lipid droplets are able to mediate the production of brown pigments that are morphologically and chemically identical to hemozoin. The partitioning of heme into these SNLDs was examined by employing Nile Red, a lipid specific dye. Soluble ferriprotoporphyrin IX was observed to spontaneously localize to the lipid droplets, partitioning in a pH-dependent manner with an estimated log P of 2.6. Interestingly, the pH profile of heme partitioning closely resembles that of β-hematin formation. Differential scanning calorimetry and kinetic studies demonstrated that the SNLDs provide a unique environment that promotes hemozoin formation. SNLD-mediated formation of the malaria pigment displayed an activation energy barrier lower than those of individual lipid components. In particular, lipid droplets composed of diglycerides displayed activation barriers lower than those composed of monoglycerides. This difference was attributed to the greater fluidity of these lipids. In conjunction with the known pattern of lipid body proliferation, it is suggested that neutral lipid structures within the digestive vacuole not only are the location of in vivo hemozoin formation but are also essential for the survival of the parasite by functioning as a kinetically competent and site specific mediator for heme detoxification.

  17. Nanostructured lipid system as a strategy to improve the anti-Candida albicans activity of Astronium sp.

    PubMed Central

    Bonifácio, Bruna Vidal; Ramos, Matheus Aparecido dos Santos; da Silva, Patrícia Bento; Negri, Kamila Maria Silveira; de Oliveira Lopes, Érica; de Souza, Leonardo Perez; Vilegas, Wagner; Pavan, Fernando Rogério; Chorilli, Marlus; Bauab, Taís Maria

    2015-01-01

    The genus Astronium (Anacardiaceae) includes species, such as Astronium fraxinifolium, Astronium graveolens, and Astronium urundeuva, which possess anti-inflammatory, anti-ulcerogenic, healing, and antimicrobial properties. Nanostructured lipid systems are able to potentiate the action of plant extracts, reducing the required dose and side effects and improving antimicrobial activity. This work aims to evaluate a nanostructured lipid system that was developed as a strategy to improve the anti-Candida albicans activity of hydroethanolic extracts of stems and leaves from Astronium sp. The antifungal activity against C. albicans (ATCC 18804) was evaluated in vitro by a microdilution technique. In addition to the in vitro assays, the Astronium sp. that showed the best antifungal activity and selectivity index was submitted to an in vivo assay using a model of vulvovaginal candidiasis infection. In these assays, the extracts were either used alone or were incorporated into the nanostructured lipid system (comprising 10% oil phase, 10% surfactant, and 80% aqueous phase). The results indicated a minimal inhibitory concentration of 125.00 µg/mL before incorporation into the nanostructured system; this activity was even more enhanced when this extract presented a minimal inhibitory concentration of 15.62 µg/mL after its incorporation. In vivo assay dates showed that the nanostructure-incorporated extract of A. urundeuva leaves was more effective than both the unincorporated extract and the antifungal positive control (amphotericin B). These results suggest that this nanostructured lipid system can be used in a strategy to improve the in vitro and in vivo anti-C. albicans activity of hydroethanolic extracts of Astronium sp. PMID:26300640

  18. Structure And Gene Silencing Activities of Monovalent And Pentavalent Cationic Lipid Vectors Complexed With Sirna

    SciTech Connect

    Bouxsein, N.F.; McAllister, C.S.; Ewert, K.K.; Samuel, C.E.; Safinya, C.R.; /UC, Santa Barbara

    2007-07-03

    Small interfering RNAs (siRNAs) of 19-25 bp mediate the cleavage of complementary mRNA, leading to post-transcriptional gene silencing. We examined cationic lipid (CL)-mediated delivery of siRNA into mammalian cells and made comparisons to CL-based DNA delivery. The effect of lipid composition and headgroup charge on the biophysical and biological properties of CL-siRNA vectors was determined. X-ray diffraction revealed that CL-siRNA complexes exhibited lamellar and inverted hexagonal phases, qualitatively similar to CL-DNA complexes, but also formed other nonlamellar structures. Surprisingly, optimally formulated inverted hexagonal 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) CL-siRNA complexes exhibited high toxicity and much lower target-specific gene silencing than lamellar CL-siRNA complexes even though optimally formulated, inverted hexagonal CL-DNA complexes show high transfection efficiency in cell culture. We further found that efficient silencing required cationic lipid/nucleic acid molar charge ratios (chg) nearly an order of magnitude larger than those yielding efficiently transfecting CL-DNA complexes. This second unexpected finding has implications for cell toxicity. Multivalent lipids (MVLs) require a smaller number of cationic lipids at a given chg of the complex. Consistent with this observation, the pentavalent lipid MVL5 exhibited lower toxicity and superior silencing efficiency over a large range in both the lipid composition and chg when compared to monovalent DOTAP. Most importantly, MVL5 achieved much higher total knockdown of the target gene in CL-siRNA complex regimes where toxicity was low. This property of CL-siRNA complexes contrasts to CL-DNA complexes, where the optimized transfection efficiencies of multivalent and monovalent lipids are comparable.

  19. One-dimensional potential of mean force underestimates activation barrier for transport across flexible lipid membranes

    NASA Astrophysics Data System (ADS)

    Kopelevich, Dmitry I.

    2013-10-01

    Transport of a fullerene-like nanoparticle across a lipid bilayer is investigated by coarse-grained molecular dynamics (MD) simulations. Potentials of mean force (PMF) acting on the nanoparticle in a flexible bilayer suspended in water and a bilayer restrained to a flat surface are computed by constrained MD simulations. The rate of the nanoparticle transport into the bilayer interior is predicted using one-dimensional Langevin models based on these PMFs. The predictions are compared with the transport rates obtained from a series of direct (unconstrained) MD simulations of the solute transport into the flexible bilayer. It is observed that the PMF acting on the solute in the flexible membrane underestimates the transport rate by more than an order of magnitude while the PMF acting on the solute in the restrained membrane yields an accurate estimate of the activation energy for transport into the flexible membrane. This paradox is explained by a coexistence of metastable membrane configurations for a range of the solute positions inside and near the flexible membrane. This leads to a significant reduction of the contribution of the transition state to the mean force acting on the solute. Restraining the membrane shape ensures that there is only one stable membrane configuration corresponding to each solute position and thus the transition state is adequately represented in the PMF. This mechanism is quite general and thus this phenomenon is expected to occur in a wide range of interfacial systems. A simple model for the free energy landscape of the coupled solute-membrane system is proposed and validated. This model explicitly accounts for effects of the membrane deformations on the solute transport and yields an accurate prediction of the activation energy for the solute transport.

  20. Membrane lipid peroxidation in neurodegeneration: Role of thrombin and proteinase-activated receptor-1.

    PubMed

    Citron, Bruce A; Ameenuddin, Syed; Uchida, K; Suo, William Z; SantaCruz, Karen; Festoff, Barry W

    2016-07-15

    Thrombin and membrane lipid peroxidation (MLP) have been implicated in various central nervous system (CNS) disorders from CNS trauma to stroke, Alzheimer's (AD) and Parkinson's (PD) diseases. Because thrombin also induces MLP in platelets and its involvement in neurodegenerative diseases we hypothesized that its deleterious effects might, in part, involve formation of MLP in neuronal cells. We previously showed that thrombin induced caspase-3 mediated apoptosis in motor neurons, via a proteinase-activated receptor (PAR1). We have now investigated thrombin's influence on the oxidative state of neurons leading to induction of MLP-protein adducts. Translational relevance of thrombin-induced MLP is supported by increased levels of 4-hydroxynonenal-protein adducts (HNEPA) in AD and PD brains. We now report for the first time that thrombin dose-dependently induces formation of HNEPA in NSC34 mouse motor neuron cells using anti-HNE and anti-acrolein monoclonal antibodies. The most prominent immunoreactive band, in SDS-PAGE, was at ∼54kDa. Membrane fractions displayed higher amounts of the protein-adduct than cytosolic fractions. Thrombin induced MLP was mediated, at least in part, through PAR1 since a PAR1 active peptide, PAR1AP, also elevated HNEPA levels. Of interest, glutamate and Fe2SO4 also increased the ∼54kDa HNEPA band in these cells but to a lesser extent. Taken together our results implicate the involvement of thrombin and MLP in neuronal cell loss observed in various CNS degenerative and traumatic pathologies.

  1. Effects of platelet activating factor and related lipids on phase transition of dipalmitoylphosphatidylcholine.

    PubMed

    Bratton, D L; Harris, R A; Clay, K L; Henson, P M

    1988-06-07

    Recent evidence localizing the inflammatory mediator, platelet activating factor, (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) to the membranes of stimulated neutrophils raises the possibility that PAF may, in addition to its activities as a mediator, alter the physical properties of membranes. Accordingly, the effects of PAF and related alkyl ether and acyl analogs on phase transition thermodynamics of dipalmitoylphosphatidylcholine (DPPC) were studied using fluorescence polarization of the fluorescent probe, 1,6-diphenyl-1,3,5-hexatriene (DPH). PAF, its ester analog (1-palmitoyl-2-acetylphosphatidylcholine) and both the corresponding alkyl and acyl lysophospholipid analogs (each at a concentration of 10 mol%) significantly decreased the phase transition temperature and broadened the phase transition of DPPC (P less than 0.05). The relative potency of the lipids in causing this effect was ester-PAF greater than or equal to PAF greater than or equal to lyso-PAF greater than lyso-PC suggesting that the fluidization of the synthetic membranes was attributable to both the 2-position acetyl group and the 1-position alkyl linkage. Furthermore, using various related compounds, increases in chain length and degree of unsaturation in the 2-position were shown to enhance the depression in transition temperature and broadening of the phase transition. Phase transition thermodynamics were also assessed using differential scanning calorimetry. Similar depression in the phase transition temperature was measured for PAF and both the alkyl and acyl lysophospholipids. Broadening of the phase transition for DPPC by the various analogs was assessed by calculation of transition peak width and cooperative unit. Data from fluorescence polarization and differential scanning calorimetry provide similar though not identical results and support the hypothesis that the unique features of PAF may alter membrane physical properties and could ultimately explain some of its biologic

  2. One-dimensional potential of mean force underestimates activation barrier for transport across flexible lipid membranes.

    PubMed

    Kopelevich, Dmitry I

    2013-10-07

    Transport of a fullerene-like nanoparticle across a lipid bilayer is investigated by coarse-grained molecular dynamics (MD) simulations. Potentials of mean force (PMF) acting on the nanoparticle in a flexible bilayer suspended in water and a bilayer restrained to a flat surface are computed by constrained MD simulations. The rate of the nanoparticle transport into the bilayer interior is predicted using one-dimensional Langevin models based on these PMFs. The predictions are compared with the transport rates obtained from a series of direct (unconstrained) MD simulations of the solute transport into the flexible bilayer. It is observed that the PMF acting on the solute in the flexible membrane underestimates the transport rate by more than an order of magnitude while the PMF acting on the solute in the restrained membrane yields an accurate estimate of the activation energy for transport into the flexible membrane. This paradox is explained by a coexistence of metastable membrane configurations for a range of the solute positions inside and near the flexible membrane. This leads to a significant reduction of the contribution of the transition state to the mean force acting on the solute. Restraining the membrane shape ensures that there is only one stable membrane configuration corresponding to each solute position and thus the transition state is adequately represented in the PMF. This mechanism is quite general and thus this phenomenon is expected to occur in a wide range of interfacial systems. A simple model for the free energy landscape of the coupled solute-membrane system is proposed and validated. This model explicitly accounts for effects of the membrane deformations on the solute transport and yields an accurate prediction of the activation energy for the solute transport.

  3. Ginsenoside Rh2 induces ligand-independent Fas activation via lipid raft disruption

    SciTech Connect

    Yi, Jae-Sung; Choo, Hyo-Jung; Cho, Bong-Rae; Kim, Hwan-Myung; Kim, Yong-Nyun; Ham, Young-Mi; Ko, Young-Gyu

    2009-07-24

    Lipid rafts are plasma membrane platforms mediating signal transduction pathways for cellular proliferation, differentiation and apoptosis. Here, we show that membrane fluidity was increased in HeLa cells following treatment with ginsenoside Rh2 (Rh2), as determined by cell staining with carboxy-laurdan (C-laurdan), a two-photon dye designed for measuring membrane hydrophobicity. In the presence of Rh2, caveolin-1 appeared in non-raft fractions after sucrose gradient ultracentrifugation. In addition, caveolin-1 and GM1, lipid raft landmarkers, were internalized within cells after exposure to Rh2, indicating that Rh2 might disrupt lipid rafts. Since cholesterol overloading, which fortifies lipid rafts, prevented an increase in Rh2-induced membrane fluidity, caveolin-1 internalization and apoptosis, lipid rafts appear to be essential for Rh2-induced apoptosis. Moreover, Rh2-induced Fas oligomerization was abolished following cholesterol overloading, and Rh2-induced apoptosis was inhibited following treatment with siRNA for Fas. This result suggests that Rh2 is a novel lipid raft disruptor leading to Fas oligomerization and apoptosis.

  4. Lipid Tail Protrusion in Simulations Predicts Fusogenic Activity of Influenza Fusion Peptide Mutants and Conformational Models

    PubMed Central

    Larsson, Per; Kasson, Peter M.

    2013-01-01

    Fusion peptides from influenza hemagglutinin act on membranes to promote membrane fusion, but the mechanism by which they do so remains unknown. Recent theoretical work has suggested that contact of protruding lipid tails may be an important feature of the transition state for membrane fusion. If this is so, then influenza fusion peptides would be expected to promote tail protrusion in proportion to the ability of the corresponding full-length hemagglutinin to drive lipid mixing in fusion assays. We have performed molecular dynamics simulations of influenza fusion peptides in lipid bilayers, comparing the X-31 influenza strain against a series of N-terminal mutants. As hypothesized, the probability of lipid tail protrusion correlates well with the lipid mixing rate induced by each mutant. This supports the conclusion that tail protrusion is important to the transition state for fusion. Furthermore, it suggests that tail protrusion can be used to examine how fusion peptides might interact with membranes to promote fusion. Previous models for native influenza fusion peptide structure in membranes include a kinked helix, a straight helix, and a helical hairpin. Our simulations visit each of these conformations. Thus, the free energy differences between each are likely low enough that specifics of the membrane environment and peptide construct may be sufficient to modulate the equilibrium between them. However, the kinked helix promotes lipid tail protrusion in our simulations much more strongly than the other two structures. We therefore predict that the kinked helix is the most fusogenic of these three conformations. PMID:23505359

  5. Effects of chilled storage and cryopreservation on sperm characteristics, antioxidant enzyme activities, and lipid peroxidation in Pacific cod Gadus microcephalus

    NASA Astrophysics Data System (ADS)

    Wang, Xueying; Shi, Xuehui; Liu, Yifan; Yu, Daode; Guan, Shuguang; Liu, Qinghua; Li, Jun

    2016-07-01

    The present study evaluated the effects of chilled storage and cryopreservation on sperm motion characteristics, antioxidant enzyme activities, and lipid peroxidation in the Pacific cod Gadus macrocephalus. Sperm motility and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (Gr), and lipid peroxidation (measured via malondialdehyde (MDA) content) were determined after the milt was stored at 4°C for 12 h, cryopreserved without cryoprotectant in 12% propylene glycol (PG), cryopreserved in 12% PG+0.1 mol/L trehalose, or cryopreserved in 12% PG spermatozoa but centrifuged to decant the supernatant prior to cryopreservation (only sperm cells were cryopreserved). After chilled storage or cryopreservation, the SOD, CAT and GPx activities were reduced in sperm cells and increased in seminal plasma in almost all treatments; sperm motility parameters were also decreased. However, the addition of trehalose into the cryoprotectant could significantly improve the postthaw sperm quality as revealed by the sperm average path velocity. This improvement might be attributed to the function of trehalose in scavenging reactive oxygen species. Chilled storage and cryopreservation had significant effects on sperm motion characteristics, antioxidant enzyme activities, and lipid peroxidation in the Pacific cod.

  6. Effect of tea polyphenols on lipid peroxidation and antioxidant activity of litchi (Litchi chinensis Sonn.) fruit during cold storage.

    PubMed

    Chen, Wenrong; Zhang, Zhenzhen; Shen, Yanwen; Duan, Xuewu; Jiang, Yuemin

    2014-10-20

    To understand the potential of application of tea polyphenols to the shelf life extension and quality maintenance of litchi (Litchi chinensis Sonn.) fruit, the fruits were dipped into a solution of 1% tea phenols for 5 min before cold storage at 4 °C. Changes in browning index, contents of anthocyanins and phenolic compounds, superoxide dismutase (SOD) and peroxidase (POD) activities, O2.- production rate and H2O2 content, levels of relative leakage rate and lipid peroxidation, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were measured after 0, 10, 20 and 30 days of cold storage. The results showed that application of tea polyphenols markedly delayed pericarp browning, alleviated the decreases in contents of total soluble solids (TSS) and ascorbic acid, and maintained relatively high levels of total phenolics and anthocyanins of litchi fruit after 30 days of cold storage. Meanwhile, the treatment reduced the increases in relative leakage rate and lipid peroxidation content, delayed the increases in both O2.- production rate and H2O2 contents, and increased SOD activity but reduced POD activity throughout this storage period. These data indicated that the delayed pericarp browning of litchi fruit by the treatment with tea polyphenols could be due to enhanced antioxidant capability, reduced accumulations of reactive oxygen species and lipid peroxidation, and improved membrane integrity.

  7. TRAIL-activated EGFR by Cbl-b-regulated EGFR redistribution in lipid rafts antagonises TRAIL-induced apoptosis in gastric cancer cells.

    PubMed

    Xu, Ling; Zhang, Ye; Liu, Jing; Qu, Jinglei; Hu, Xuejun; Zhang, Fan; Zheng, Huachuan; Qu, Xiujuan; Liu, Yunpeng

    2012-11-01

    Most gastric cancer cells are resistant to tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). Since TRAIL resistance is associated with lipid rafts, in which both death receptors and epidermal growth factor receptors (EGFR) are enriched, our aim is to identify how lipid raft-regulated receptor redistribution influences the sensitivity of TRAIL in gastric cancer cells. In TRAIL-resistant gastric cancer cells, TRAIL did not induce effective death-inducing signalling complex (DISC) formation in lipid rafts, accompanied with EGFR translocation into lipid rafts, and activation of EGFR pathway. Knockdown of casitas B-lineage lymphoma-b (Cbl-b) enhanced TRAIL-induced apoptosis by promoting DISC formation in lipid rafts. However, knockdown of Cbl-b also enhanced EGFR translocation into lipid rafts and EGFR pathway activation induced by TRAIL. Either using inhibitors of EGFR or depletion of EGFR with small interfering RNA (siRNA) prevented EGFR pathway activation, and thus increased TRAIL-induced apoptosis, especially in Cbl-b knockdown clones. Taken together, TRAIL-induced EGFR activation through Cbl-b-regulated EGFR redistribution in lipid rafts antagonised TRAIL-induced apoptosis. The contribution of DISC formation and the inhibition of EGFR signal triggered in lipid rafts are both essential for increasing the sensitivity of gastric cancer cells to TRAIL.

  8. Antioxidant Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry

    PubMed Central

    Muhlisin; Utama, Dicky Tri; Lee, Jae Ho; Choi, Ji Hye; Lee, Sung Ki

    2016-01-01

    This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus) were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT) in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx) in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD) activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat. PMID:26954148

  9. Nanostructured Lipid Carriers (NLC) as Vehicles for Topical Administration of Sesamol: In Vitro Percutaneous Absorption Study and Evaluation of Antioxidant Activity.

    PubMed

    Puglia, Carmelo; Lauro, Maria Rosaria; Offerta, Alessia; Crascì, Lucia; Micicchè, Lucia; Panico, Anna Maria; Bonina, Francesco; Puglisi, Giovanni

    2017-03-01

    Sesamol is a natural phenolic compound extracted from Sesamum indicum seed oil. Sesamol is endowed with several beneficial effects, but its use as a topical agent is strongly compromised by unfavorable chemical-physical properties. Therefore, to improve its characteristics, the aim of the present work was the formulation of nanostructured lipid carriers as drug delivery systems for topical administration of sesamol.Two different nanostructured lipid carrier systems have been produced based on the same solid lipid (Compritol® 888 ATO) but in a mixture with two different kinds of oil phase such as Miglyol® 812 (nanostructured lipid carrier-M) and sesame oil (nanostructured lipid carrier-PLUS). Morphology and dimensional distribution of nanostructured lipid carriers have been characterized by differential scanning calorimetry and photon correlation spectroscopy, respectively. The release pattern of sesamol from nanostructured lipid carriers was evaluated in vitro determining drug percutaneous absorption through excised human skin. Furthermore, an oxygen radical absorbance capacity assay was used to determine their antioxidant activity.From the results obtained, the method used to formulate nanostructured lipid carriers led to a homogeneous dispersion of particles in a nanometric range. Sesamol has been encapsulated efficiently in both nanostructured lipid carriers, with higher encapsulation efficiency values (> 90 %) when sesame oil was used as the oil phase (nanostructured lipid carrier-PLUS). In vitro evidences show that nanostructured lipid carrier dispersions were able to control the rate of sesamol diffusion through the skin, with respect to the reference formulations.Furthermore, the oxygen radical absorbance capacity assay pointed out an interesting and prolonged antioxidant activity of sesamol, especially when vehiculated by nanostructured lipid carrier-PLUS.

  10. Preparation and Characterization of Three Tilmicosin-loaded Lipid Nanoparticles: Physicochemical Properties and in-vitro Antibacterial Activities

    PubMed Central

    Al-Qushawi, Alwan; Rassouli, Ali; Atyabi, Fatemeh; Peighambari, Seyed Mostafa; Esfandyari-Manesh, Mehdi; Shams, Gholam Reza; Yazdani, Azam

    2016-01-01

    Tilmicosin (TLM) is an important antibiotic in veterinary medicine with low bioavailability and safety. This study aimed to formulate and evaluate physicochemical properties, storage stability after lyophilization, and antibacterial activity of three TLM-loaded lipid nanoparticles (TLM-LNPs) including solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), and lipid-core nanocapsules (LNCs). Physicochemical parameters such as particle size-mean diameter, polydispersity index, zeta potential, drug encapsulation efficiency (EE), loading capacity, and morphology of the formulations were evaluated and the effects of various cryoprotectants during lyophilization and storage for 8 weeks were also studied. The profiles of TLM release and the antibacterial activities of these TLM-LNPs suspensions (against Escherichia coli and Staphylococcus aureus) were tested in comparison with their corresponding powders. TLM-LNPs suspensions were in nano-scale range with mean diameters of 186.3 ± 1.5, 149.6 ± 3.0, and 85.0 ± 1.0nm, and also EE, 69.1, 86.3, and 94.3% for TLM- SLNs, TLM-NLCs, and TLM- LNCs respectively. TLM-LNCs gave the best results with significantly low particle size and high EE (p<0.05). Mannitol was the most effective cryoprotectant for lyophilization and storage of TLM-LNPs. The drug release profiles were biphasic and the release times were longer at pH 7.4 where TLM-NLCs and TLM-LNCs powders showed longer release times. In microbiological tests, S. aureus was about 4 times more sensitive than E. coli to TLM-LNPs with minimum inhibitory concentration ranges of 0.5-1.0 and 2-4 µg/mL respectively, and TLM-LNCs exhibited the best antibacterial activities. In conclusion, TLM-LNP formulations especially TLM-LNCs and TLM-NLCs are promising carriers for TLM with better drug encapsulation capacity, release behavior, and antibacterial activity. PMID:28261309

  11. Anthocyanin content, lipid peroxidation and cyclooxygenase enzyme inhibitory activities of sweet and sour cherries.

    PubMed

    Mulabagal, Vanisree; Lang, Gregory A; DeWitt, David L; Dalavoy, Sanjeev S; Nair, Muraleedharan G

    2009-02-25

    Cherries contain bioactive anthocyanins that are reported to possess antioxidant, anti-inflammatory, anticancer, antidiabetic and antiobese properties. The present study revealed that red sweet cherries contained cyanidin-3-O-rutinoside as major anthocyanin (>95%). The sweet cherry cultivar "Kordia" (aka "Attika") showed the highest cyanidin-3-O-rutinoside content, 185 mg/100 g fresh weight. The red sweet cherries "Regina" and "Skeena" were similar to "Kordia", yielding cyanidin-3-O-rutinoside at 159 and 134 mg/100 g fresh weight, respectively. The yields of cyanidin-3-O-glucosylrutinoside and cyanidin-3-O-rutinoside were 57 and 19 mg/100 g fresh weight in "Balaton" and 21 and 6.2 mg/100 g fresh weight in "Montmorency", respectively, in addition to minor quantities of cyanidin-3-O-glucoside. The water extracts of "Kordia", "Regina", "Glacier" and "Skeena" sweet cherries gave 89, 80, 80 and 70% of lipid peroxidation (LPO) inhibition, whereas extracts of "Balaton" and "Montmorency" were in the range of 38 to 58% at 250 microg/mL. Methanol and ethyl acetate extracts of the yellow sweet cherry "Rainier" containing beta-carotene, ursolic, coumaric, ferulic and cafeic acids inhibited LPO by 78 and 79%, respectively, at 250 microg/mL. In the cyclooxygenase (COX) enzyme inhibitory assay, the red sweet cherry water extracts inhibited the enzymes by 80 to 95% at 250 microg/mL. However, the methanol and ethyl acetate extracts of "Rainier" and "Gold" were the most active against COX-1 and -2 enzymes. Water extracts of "Balaton" and "Montmorency" inhibited COX-1 and -2 enzymes by 84, and 91 and 77, and 87%, respectively, at 250 microg/mL.

  12. Lipid bilayer nanodisc platform for investigating polyprenol-dependent enzyme interactions and activities

    PubMed Central

    Hartley, Meredith D.; Schneggenburger, Philipp E.; Imperiali, Barbara

    2013-01-01

    Membrane-bound polyprenol-dependent pathways are important for the assembly of essential glycoconjugates in all domains of life. However, despite their prevalence, the functional significance of the extended linear polyprenyl groups in the interactions of the glycan substrates, the biosynthetic enzymes that act upon them, and the membrane bilayer in which they are embedded remains a mystery. These interactions are investigated simultaneously and uniquely through application of the nanodisc membrane technology. The Campylobacter jejuni N-linked glycosylation pathway has been chosen as a model pathway in which all of the enzymes and substrates are biochemically accessible. We present the functional reconstitution of two enzymes responsible for the early membrane-committed steps in glycan assembly. Protein stoichiometry analysis, fluorescence-based approaches, and biochemical activity assays are used to demonstrate the colocalization of the two enzymes in nanodiscs. Isotopic labeling of the substrates reveals that undecaprenyl-phosphate is coincorporated into discs with the two enzymes, and furthermore, that both enzymes are functionally reconstituted and can sequentially convert the coembedded undecaprenyl-phosphate into undecaprenyl-diphosphate-linked disaccharide. These studies provide a proof-of-concept demonstrating that the nanodisc model membrane system represents a promising experimental platform for analyzing the multifaceted interactions among the enzymes involved in polyprenol-dependent glycan assembly pathways, the membrane-associated substrates, and the lipid bilayer. The stage is now set for exploration of the roles of the conserved polyprenols in promoting protein–protein interactions among pathway enzymes and processing of substrates through sequential steps in membrane-associated glycan assembly. PMID:24302767

  13. Physical Activity and Lipid Profile in the ELSA-Brasil Study

    PubMed Central

    da Silva, Raquel Caroline; Diniz, Maria de Fátima Haueisen Sander; Alvim, Sheila; Vidigal, Pedro Guatimosim; Fedeli, Ligia Maria Giongo; Barreto, Sandhi Maria

    2016-01-01

    Background Regular physical activity (PA) induces desirable changes in plasma levels of high- and low-density lipoproteins (HDL and LDL, respectively) and triglycerides (TG), important risk factors for cardiometabolic diseases. However, doubts whether intensity and duration have equivalent benefits remain. Objective To assess the association of PA intensity and duration with HDL, LDL and TG levels. Methods Cross-sectional study with 12,688 participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) baseline, who were not on lipid-lowering medication. After adjustment for important covariates, multiple linear regression was used to assess the association of PA intensity and duration with HDL, LDL and TG (natural logarithm) levels. Results Both moderate and vigorous PA and PA practice ≥ 150 min/week were significantly associated with higher HDL and lower TG levels. Vigorous PA was associated with lower LDL only on univariate analysis. After adjustments, moderate and vigorous PA increased mean HDL level by 0.89 mg/dL and 1.71 mg/dL, respectively, and reduced TG geometric mean by 0.98 mg/dL and 0.93 mg/dL, respectively. PA practice ≥ 150 min/week increased mean HDL level by 1.05 mg/dL, and decreased TG geometric mean by 0.98 mg/dL. Conclusion Our findings reinforce the benefits of both PA parameters studied on HDL and TG levels, with a slight advantage for vigorous PA as compared to the recommendation based only on PA duration. PMID:27355470

  14. Lipids, lipoproteins, fibrinogen and fibrinolytic activity in angiographically assessed coronary heart disease.

    PubMed

    Lipinska, I; Gurewich, V; Meriam, C M; Kosowsky, B D; Ramaswamy, K; Philbin, E; Losordo, D

    1987-01-01

    Plasma lipids, lipoproteins, fibrinogen and fibrinolytic activity (FA) were measured in 202 consecutive patients undergoing coronary angiography. Twenty-one patients, 13 men and 8 women with a mean age of 52.8 years and 56.7 years respectively, were found to be angiographically free of coronary artery disease (CAD) and served as the principal control group. Since this group contained a disproportionate number of subjects with risk factors such as family history, hypertension and smoking, a second control group of clinically healthy subjects selected for age was also tested. Their laboratory results were not used in the statistical calculations. The group with angiographic CAD consisted of 130 men (mean age 57.6 years) and 51 women (mean age 61.5 years). Abnormal angiograms were graded according to the number of major vessels with more than 50% stenosis involved. The laboratory variables which were significantly (p less than .01-.001) associated with the presence of CAD were: High density lipoprotein (HDL) when determined by polyacrylamide gel electrophoresis (PAGE) and expressed as a percentage of total lipoproteins rather than concentration, presence of Intermediate Density Lipoprotein (IDL), percent of Very Low Density Lipoprotein (VLDL), fibrinogen concentration and FA. The HDL2 subfraction was significantly inversely correlated only in women. The total plasma cholesterol was normal and virtually identical in both groups. Within the CAD group, only two of the laboratory results were significantly correlated with the extent of disease. By univariate analysis, the FA showed the closest association with the score for severity of CAD (p less than .001) followed by the presence of IDL (p less than .01). In conclusion, lipoprotein analysis by a method which measures not only HDL, but also LDL, VLDL and IDL, together with the determination of fibrinogen and FA provides information useful in the identification of individuals at risk for CAD.

  15. Lipid nanocarriers of a lipid-conjugated estrogenic derivative inhibit tumor growth and enhance cisplatin activity against triple-negative breast cancer: pharmacokinetic and efficacy evaluation.

    PubMed

    Andey, Terrick; Sudhakar, Godeshala; Marepally, Srujan; Patel, Apurva; Banerjee, Rajkumar; Singh, Mandip

    2015-04-06

    Breast cancer is the leading cause of malignancies among women globally. The triple negative breast cancer (TNBC) subtype is the most difficult to treat and accounts for 15% of all cases. Targeted therapies have been developed for TNBC but come short of clinical translation due to acquired tumor resistance. An effective therapy against TNBC must combine properties of target specificity, efficient tumor killing, and translational relevance. The objective of this study was to formulate a nontoxic, cationic, lipid-conjugated estrogenic derivative (ESC8), with demonstrated anticancer activity, for oral delivery in mice bearing triple negative breast cancer (TNBC) as xenograft tumors. The in vitro cell viability, Caco-2 permeability, and cell cycle dynamics of ESC8-treated TNBC cells were investigated. ESC8 was formulated as liposomes, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs) and characterized for size, zeta potential, entrapment efficiency, size stability, and tumor biodistribution. Pharmacokinetic modeling of plasma concentration-time course data was carried out following intravenous and oral administration in Sprague-Dawley rats. In vivo efficacy investigation of ESC8-SLNC was carried out in Nu/Nu mice bearing MDA-MB-231 TNBC as xenograft tumors, and the molecular dynamics modulating tumor growth inhibition was analyzed by Western blot. In vitro ESC8 inhibited TNBC and non-TNBC cell viability with IC50 ranging from 1.81 to 3.33 μM. ESC8 was superior to tamoxifen and Cisplatin in inhibiting MDA-MB-231 cell viability; and at 2.0 μM ESC8 enhanced Cisplatin cytotoxicity 16-fold. Intravenous ESC8 (2.0 mg/kg) was eliminated at a rate of 0.048 ± 0.01 h(-1) with a half-life of 14.63 ± 2.95 h in rats. ESC8 was orally bioavailable (47.03%) as solid lipid nanoparticles (ESC8-SLN). ESC8-SLN (10 mg/kg/day, ×14 days, p.o.) inhibited breast tumor growth by 74% (P < 0.0001 vs control) in mice bearing MDA-MB-231 cells as xenografts; and when

  16. Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism.

    PubMed

    Jouffe, Céline; Gobet, Cédric; Martin, Eva; Métairon, Sylviane; Morin-Rivron, Delphine; Masoodi, Mojgan; Gachon, Frédéric

    2016-04-21

    Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape.

  17. Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism

    PubMed Central

    Jouffe, Céline; Gobet, Cédric; Martin, Eva; Métairon, Sylviane; Morin-Rivron, Delphine; Masoodi, Mojgan; Gachon, Frédéric

    2016-01-01

    Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape. PMID:27097688

  18. Lipid-laden cells differentially distributed in the aging brain are functionally active and correspond to distinct phenotypes.

    PubMed

    Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M; Batista, Claudia Maria de Castro; Mattson, Mark P; Mello Coelho, Valeria de

    2016-03-31

    We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN(+) LLC. Some cortical NeuN(+) neurons, GFAP(+) glia limitans astrocytes, Iba-1(+) microglia and S100β(+) ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes.

  19. Role of membrane cholesterol and lipid peroxidation in regulating the Na+/K+-ATPase activity in schizophrenia

    PubMed Central

    Roy, Suparna; Dasgupta, Anindya; Banerjee, Ushasi; Chowdhury, Piali; Mukhopadhyay, Ashis; Saha, Gautam; Singh, Omprakash

    2016-01-01

    Background: Na+/K+-ATPase (NKA) activity is compromised in several neuropsychiatric disorders. Oxidative stress and membrane lipid composition play important roles in regulating NKA activity. Aims: The present study was undertaken to evaluate the effects of oxidative stress-induced membrane lipid damage and membrane cholesterol composition on NKA pump activity in schizophrenia. Settings and Design: It was a hospital-based, cross-sectional, observational study in 49 cases and 51 controls for 1 year. Materials and Methods: NKA pump activity in red blood cell membrane, serum levels of thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC) adducts, and cholesterol were measured by standard spectrophotometric techniques in newly diagnosed schizophrenia patients by Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criteria. Membrane cholesterol was analyzed by chloroform and isopropanol extraction followed by measuring the cholesterol concentration by spectrophotometric technique. Statistical Analysis and Results: Mean values for NKA pump activity, membrane cholesterol level, and serum cholesterol levels were significantly lower in the case group (P < 0.001). The activity of NKA pump was found to be directly correlated to membrane cholesterol level rather than with the serum cholesterol values. Although the NKA pump activity showed inverse relationship with the serum values of TBARS and PC products both, on multiple linear regression analysis, it was found to be significantly positively dependent on the membrane cholesterol (β = 0.268, P = 0.01) and negatively dependent on the serum TBARS (β = −0.63, P < 0.001) levels only. Conclusion: Reduced membrane cholesterol and oxidative stress-induced damage to membrane lipids play crucial roles in decreasing the NKA activity in schizophrenia. Hence, for a better prognosis and treatment, measures are required to maintain optimum levels of cholesterol in neuronal tissues along

  20. Screening for lipid yielding microalgae: activities for 1983. Final subcontract report

    SciTech Connect

    Thomas, W. H.; Tornabene, T. G.; Weissman, J.

    1984-04-01

    The SERI/DOE Aquatic Species Program is conducting a screening project, to select microalgae species and strains that are acceptable for liquid fuel production in outdoor culture. The emphases are on finding species that grow rapidly at high biomass density, in outdoor culture and produce large quantities of lipids. During 1983 over 100 species were isolated from saline waters at the California and Nevada deserts. Some of these species were characterized for growth response to various nutrients, temperatures, and salinities. Selected species were analyzed for lipid composition. Lipids were characterized into fractions, hydrocarbons, isoprenoids, triglyceride, glycolipids, and phospholipids. The most promising species were tested for growth and monoculture sustainability in outdoor culture. Each section (microalgae selection, chemical profiles of microalgae, mass culture of macroalgae) was abstracted separately. 51 references, 8 figures, 14 tables.

  1. By activating Fas/ceramide synthase 6/p38 kinase in lipid rafts, stichoposide D inhibits growth of leukemia xenografts.

    PubMed

    Yun, Seong-Hoon; Park, Eun-Seon; Shin, Sung-Won; Ju, Mi-Ha; Han, Jin-Yeong; Jeong, Jin-Sook; Kim, Sung-Hyun; Stonik, Valentin A; Kwak, Jong-Young; Park, Joo-In

    2015-09-29

    Stichoposide D (STD) is a marine triterpene glycoside isolated from sea cucumbers. We examined the molecular mechanisms underlying the antitumor activity of STD in human leukemia cells. The role of Fas (CD95), ceramide synthase 6 (CerS6) and p38 kinase during STD-induced apoptosis was examined in human leukemia cells. In addition, the antitumor effects of STD in K562 and HL-60 leukemia xenograft models were investigated. We found that STD induces Fas translocation to lipid rafts, and thus mediates cell apoptosis. We also observed the activation of CerS6 and p38 kinase during STD-induced apoptosis. The use of methyl-β-cyclodextrin and nystatin to disrupt lipid rafts prevents the clustering of Fas and the activation of CerS6 and p38 kinase, and also inhibits STD-induced apoptosis. Specific inhibition by Fas, CerS6, and p38 kinase siRNA transfection partially blocked STD-induced apoptosis. In addition, STD has antitumor activity through the activation of CerS6 and p38 kinase without displaying any toxicity in HL-60 and K562 xenograft models. We observed that the anti-tumor effect of STD is partially prevented in CerS6 shRNA-silenced xenograft models. We first report that Fas/CerS6/p38 kinase activation in lipid rafts by STD is involved in its anti-leukemic activity. We also established that STD is able to enhance the chemosensitivity of K562 cells to etoposide or Ara-C. These data suggest that STD may be used alone or in combination with other chemotherapeutic agents to treat leukemia.

  2. By activating Fas/ceramide synthase 6/p38 kinase in lipid rafts, Stichoposide D inhibits growth of leukemia xenografts

    PubMed Central

    Yun, Seong-Hoon; Park, Eun-Seon; Shin, Sung-Won; Ju, Mi-Ha; Han, Jin-Yeong; Jeong, Jin-Sook; Kim, Sung-Hyun; Stonik, Valentin A.; Kwak, Jong-Young; Park, Joo-In

    2015-01-01

    Stichoposide D (STD) is a marine triterpene glycoside isolated from sea cucumbers. We examined the molecular mechanisms underlying the antitumor activity of STD in human leukemia cells. The role of Fas (CD95), ceramide synthase 6 (CerS6) and p38 kinase during STD-induced apoptosis was examined in human leukemia cells. In addition, the antitumor effects of STD in K562 and HL-60 leukemia xenograft models were investigated. We found that STD induces Fas translocation to lipid rafts, and thus mediates cell apoptosis. We also observed the activation of CerS6 and p38 kinase during STD-induced apoptosis. The use of methyl-β-cyclodextrin and nystatin to disrupt lipid rafts prevents the clustering of Fas and the activation of CerS6 and p38 kinase, and also inhibits STD-induced apoptosis. Specific inhibition by Fas, CerS6, and p38 kinase siRNA transfection partially blocked STD-induced apoptosis. In addition, STD has antitumor activity through the activation of CerS6 and p38 kinase without displaying any toxicity in HL-60 and K562 xenograft models. We observed that the anti-tumor effect of STD is partially prevented in CerS6 shRNA-silenced xenograft models. We first report that Fas/CerS6/p38 kinase activation in lipid rafts by STD is involved in its anti-leukemic activity. We also established that STD is able to enhance the chemosensitivity of K562 cells to etoposide or Ara-C. These data suggest that STD may be used alone or in combination with other chemotherapeutic agents to treat leukemia. PMID:26318294

  3. Effects of α-lipoic acid and L-carnosine supplementation on antioxidant activities and lipid profiles in rats

    PubMed Central

    Kim, Mi Young; Kim, Eun Jin; Kim, Young-Nam; Choi, Changsun

    2011-01-01

    α-Lipoic acid and L-carnosine are powerful antioxidants and are often used as a health supplement and as an ergogenic aid. The objective of this study was to investigate the effects of α-lipoic acid and/or L-carnosine supplementation on antioxidant activity in serum, skin, and liver of rats and blood lipid profiles for 6 weeks. Four treatment groups received diets containing regular rat chow diet (control, CON), 0.5% α-lipoic acid (ALA), 0.25% α-lipoic acid + 0.25% L-carnosine (ALA + LC), or 0.5% L-carnosine (LC). Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and lipid peroxidation products, malondialdehyde (MDA) concentrations, were analyzed in serum, skin, and liver. Blood lipid profiles were measured, including triglycerides (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C). Skin and liver SOD activities of the ALA and LC groups were higher than those of the CON group (P < 0.05), but serum SOD activity was higher only in the LC group compared to that in the CON group (P < 0.05). Additionally, only liver GSH-Px activity in the LC group was higher than that of the CON and the other groups. Serum and skin MDA levels in the ALA and LC groups were lower than those in the CON group (P < 0.05). Serum TG and TC in the ALA and ALA + LC groups were lower than those in the CON and LC groups (P < 0.05). The HDL-C level in the LC group was higher than that in any other group (P < 0.05). LDL-C level was lower in the ALA + LC and LC groups than that in the CON group (P < 0.05). Thus, α-lipoic acid and L-carnosine supplementation increased antioxidant activity, decreased lipid peroxidation in the serum, liver, and skin of rats and positively modified blood lipid profiles. PMID:22125679

  4. Lipid A structural modifications in extreme conditions and identification of unique modifying enzymes to define the Toll-like receptor 4 structure-activity relationship.

    PubMed

    Scott, Alison J; Oyler, Benjamin L; Goodlett, David R; Ernst, Robert K

    2017-01-17

    Strategies utilizing Toll-like receptor 4 (TLR4) agonists for treatment of cancer, infectious diseases, and other targets report promising results. Potent TLR4 antagonists are also gaining attention as therapeutic leads. Though some principles for TLR4 modulation by lipid A have been described, a thorough understanding of the structure-activity relationship (SAR) is lacking. Only through a complete definition of lipid A-TLR4 SAR is it possible to predict TLR4 signaling effects of discrete lipid A structures, rendering them more pharmacologically relevant. A limited 'toolbox' of lipid A-modifying enzymes has been defined and is largely composed of enzymes from mesophile human and zoonotic pathogens. Expansion of this 'toolbox' will result from extending the search into lipid A biosynthesis and modification by bacteria living at the extremes. Here, we review the fundamentals of lipid A structure, advances in lipid A uses in TLR4 modulation, and the search for novel lipid A-modifying systems in extremophile bacteria. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.

  5. Structure-guided enzymology of the lipid A acyltransferase LpxM reveals a dual activity mechanism

    PubMed Central

    Dovala, Dustin; Rath, Christopher M.; Hu, Qijun; Sawyer, William S.; Shia, Steven; Elling, Robert A.; Knapp, Mark S.; Metzger, Louis E.

    2016-01-01

    Gram-negative bacteria possess a characteristic outer membrane, of which the lipid A constituent elicits a strong host immune response through the Toll-like receptor 4 complex, and acts as a component of the permeability barrier to prevent uptake of bactericidal compounds. Lipid A species comprise the bulk of the outer leaflet of the outer membrane and are produced through a multistep biosynthetic pathway conserved in most Gram-negative bacteria. The final steps in this pathway involve the secondary acylation of lipid A precursors. These are catalyzed by members of a superfamily of enzymes known as lysophospholipid acyltransferases (LPLATs), which are present in all domains of life and play important roles in diverse biological processes. To date, characterization of this clinically important class of enzymes has been limited by a lack of structural information and the availability of only low-throughput biochemical assays. In this work, we present the structure of the bacterial LPLAT protein LpxM, and we describe a high-throughput, label-free mass spectrometric assay to characterize acyltransferase enzymatic activity. Using our structure and assay, we identify an LPLAT thioesterase activity, and we provide experimental evidence to support an ordered-binding and “reset” mechanistic model for LpxM function. This work enables the interrogation of other bacterial acyltransferases’ structure–mechanism relationships, and the assay described herein provides a foundation for quantitatively characterizing the enzymology of any number of clinically relevant LPLAT proteins. PMID:27681620

  6. Mechanism of a Prototypical Synthetic Membrane-Active Antimicrobial: Efficient Hole-Punching Via Interaction With Negative Intrinsic Curvature Lipids

    SciTech Connect

    Yang, L.; Gordon, V.D.; Trinkle, D.R.; Schmidt, N.W.; Davis, M.A.; DeVries, C.; Som, A.; Cronan, J.E., Jr.; Tew, G.N.; Wong, G.C.L.

    2009-05-28

    Phenylene ethynylenes comprise a prototypical class of synthetic antimicrobial compounds that mimic antimicrobial peptides produced by eukaryotes and have broad-spectrum antimicrobial activity. We show unambiguously that bacterial membrane permeation by these antimicrobials depends on the presence of negative intrinsic curvature lipids, such as phosphatidylethanolamine (PE) lipids, found in high concentrations within bacterial membranes. Plate-killing assays indicate that a PE-knockout mutant strain of Escherichia coli drastically out-survives the wild type against the membrane-active phenylene ethynylene antimicrobials, whereas the opposite is true when challenged with traditional metabolic antibiotics. That the PE deletion is a lethal mutation in normative environments suggests that resistant bacterial strains do not evolve because a lethal mutation is required to gain immunity. PE lipids allow efficient generation of negative curvature required for the circumferential barrel of an induced membrane pore; an inverted hexagonal HII phase, which consists of arrays of water channels, is induced by a small number of antimicrobial molecules. The estimated antimicrobial occupation in these water channels is nonlinear and jumps from {approx}1 to 3 per 4 nm of induced water channel length as the global antimicrobial concentration is increased. By comparing to exactly solvable 1D spin models for magnetic systems, we quantify the cooperativity of these antimicrobials.

  7. Antibacterial/antifungal activity and synergistic interactions between polyprenols and other lipids isolated from Ginkgo biloba L. leaves.

    PubMed

    Tao, Ran; Wang, Cheng-Zhang; Kong, Zhen-Wu

    2013-02-07

    Polyprenols separated from lipids are promising new components from Ginkgo biloba L. leaves (GBL). In this paper, ginkgo lipids were isolated by extraction with petroleum ether, saponification, and molecular distillation. Eight known compounds: isophytol (1), nerolidol (2), linalool (3), β-sitosterol acetate (4), β-sitosterol (5), stigmasterol (6), ergosterol (7), β-sitosterol-3-O-β-D-glucopyranoside (8) and Ginkgo biloba polyprenols (GBP) were separated from GBL by chromatography and identified mainly by NMR. The separated and identified compounds 1, 2 and 3 are reported here for the first time in GBL. The 3D-DAD-HPLC-chromatogram (190-232 nm) of GBP was recorded. This study provides new evidence as there are no previous reports on antibacterial/antifungal activities and synergistic interactions between GBP and the compounds separated from GBL lipids against Salmonella enterica, Staphylocococus aureus and Aspergillus niger. Nerolidol (2) showed the highest activity among all the tested samples and of all mixture groups tested the GBP with isophytol (1) mixture had the strongest synergistic effect against Salmonella enterica among the three tested strains. A proportion of isophytol and GBP of 38.19%:61.81% (wt/wt) was determined by mixture design as the optimal proportion for the synergistic effect of GBP with isophytol against Salmonella enterica.

  8. Influence of Sorghum Kafirin on Serum Lipid Profile and Antioxidant Activity in Hyperlipidemic Rats (In Vitro and In Vivo Studies)

    PubMed Central

    Ortíz Cruz, Raquel A.; Cárdenas López, José L.; González Aguilar, Gustavo A.; Astiazarán García, Humberto; Gorinstein, Shela; Canett Romero, Rafael; Robles Sánchez, Maribel

    2015-01-01

    The aim of this study was to compare in vitro the antioxidant potential of sorghum kafirin and sorghum flour and their influence on lipids and antioxidant capacity in rats. The antioxidant activity in sorghum kafirin extract measured by the DPPH and TEAC methods was increased 30 and 65 times, respectively, compared to that of its counterpart, sorghum flour. According to electrophoresis assay, the kafirins tert-butanol extract showed a high proportion of α-kafirin monomers, and its amino acid composition revealed higher hydrophobic amino acid content such as alanine, isoleucine, leucine, tyrosine and phenylalanine than sorghum flour extract. Diets supplemented with sorghum kafirin extract have improved lipid metabolism and increased the serum antioxidant potential (67%) especially in rats fed with added cholesterol. The bioactive peptides generated from kafirin in vivo hydrolysis appear to be associated with the positive effect on serum lipids and antioxidant activity. According to these results, sorghum kafirin extract at the levels used in this study apparently could be used for prevention of atherosclerosis and other chronic diseases. PMID:26634202

  9. Structure-guided enzymology of the lipid A acyltransferase LpxM reveals a dual activity mechanism.

    PubMed

    Dovala, Dustin; Rath, Christopher M; Hu, Qijun; Sawyer, William S; Shia, Steven; Elling, Robert A; Knapp, Mark S; Metzger, Louis E

    2016-10-11

    Gram-negative bacteria possess a characteristic outer membrane, of which the lipid A constituent elicits a strong host immune response through the Toll-like receptor 4 complex, and acts as a component of the permeability barrier to prevent uptake of bactericidal compounds. Lipid A species comprise the bulk of the outer leaflet of the outer membrane and are produced through a multistep biosynthetic pathway conserved in most Gram-negative bacteria. The final steps in this pathway involve the secondary acylation of lipid A precursors. These are catalyzed by members of a superfamily of enzymes known as lysophospholipid acyltransferases (LPLATs), which are present in all domains of life and play important roles in diverse biological processes. To date, characterization of this clinically important class of enzymes has been limited by a lack of structural information and the availability of only low-throughput biochemical assays. In this work, we present the structure of the bacterial LPLAT protein LpxM, and we describe a high-throughput, label-free mass spectrometric assay to characterize acyltransferase enzymatic activity. Using our structure and assay, we identify an LPLAT thioesterase activity, and we provide experimental evidence to support an ordered-binding and "reset" mechanistic model for LpxM function. This work enables the interrogation of other bacterial acyltransferases' structure-mechanism relationships, and the assay described herein provides a foundation for quantitatively characterizing the enzymology of any number of clinically relevant LPLAT proteins.

  10. Reduction of lipid accumulation in white adipose tissues by Cassia tora (Leguminosae) seed extract is associated with AMPK activation.

    PubMed

    Tzeng, Thing-Fong; Lu, Hung-Jen; Liou, Shorong-Shii; Chang, Chia Ju; Liu, I-Min

    2013-01-15

    Natural herbal medications may be one answer to the worldwide epidemic of obesity. This study examines the effects of Cassia seed ethanol extract (CSEE) upon lipid accumulation in white adipose tissue (WAT). CSEE exhibited a significant concentration-dependent decrease in the intracellular accumulation of trigycerides in 3T3-L1 adipocytes. After being fed a high-fat diet (HFD) for 2 weeks, rats were fed CSEE (100, 200 or 300 mg/kg) once daily for 8 weeks. CSEE caused dose-related reductions in body weight gain (as well as plasma lipid levels and epididymal WAT sizes in HFD-fed rats). CSEE enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and its primary downstream targeting enzyme, acetyl-CoA carboxylase, up-regulated gene expression of carnitine palmitoyl transferase 1, and down-regulated sterol regulatory element-binding protein 1 and fatty acid synthase protein levels in epididymal WAT of HFD-fed rats. CSEE could attenuate lipid accumulation in WAT via AMPK signaling pathway activation.

  11. Modulation of hexa-acyl pyrophosphate lipid A population under Escherichia coli phosphate (Pho) regulon activation.

    PubMed

    Lamarche, Martin G; Kim, Sang-Hyun; Crépin, Sébastien; Mourez, Michael; Bertrand, Nicolas; Bishop, Russell E; Dubreuil, J Daniel; Harel, Josée

    2008-08-01

    Environmental phosphate is an important signal for microorganism gene regulation, and it has recently been shown to trigger some key bacterial virulence mechanisms. In many bacteria, the Pho regulon is the major circuit involved in adaptation to phosphate limitation. The Pho regulon is controlled jointly by the two-component regulatory system PhoR/PhoB and by the phosphate-specific transport (Pst) system, which both belong to the Pho regulon. We showed that a pst mutation results in virulence attenuation in extraintestinal pathogenic Escherichia coli (ExPEC) strains. Our results indicate that the bacterial cell surface of the pst mutants is altered. In this study, we show that pst mutants of ExPEC strains display an increased sensitivity to different cationic antimicrobial peptides and vancomycin. Remarkably, the hexa-acylated 1-pyrophosphate form of lipid A is significantly less abundant in pst mutants. Among differentially expressed genes in the pst mutant, lpxT coding for an enzyme that transfers a phosphoryl group to lipid A, forming the 1-diphosphate species, was found to be downregulated. Our results strongly suggest that the Pho regulon is involved in lipid A modifications, which could contribute to bacterial surface perturbations. Since the Pho regulon and the Pst system are conserved in many bacteria, such a lipid A modification mechanism could be widely distributed among gram-negative bacterial species.

  12. Acid sphingomyelinase activity is regulated by membrane lipids and facilitates cholesterol transfer by NPC2[S

    PubMed Central

    Oninla, Vincent O.; Breiden, Bernadette; Babalola, Jonathan O.; Sandhoff, Konrad

    2014-01-01

    During endocytosis, membrane components move to intraluminal vesicles of the endolysosomal compartment for digestion. At the late endosomes, cholesterol is sorted out mainly by two sterol-binding proteins, Niemann-Pick protein type C (NPC)1 and NPC2. To study the NPC2-mediated intervesicular cholesterol transfer, we developed a liposomal assay system. (Abdul-Hammed, M., B. Breiden, M. A. Adebayo, J. O. Babalola, G. Schwarzmann, and K. Sandhoff. 2010. Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion. J. Lipid Res. 51: 1747–1760.) Anionic lipids stimulate cholesterol transfer between liposomes while SM inhibits it, even in the presence of anionic bis(monoacylglycero)phosphate (BMP). Preincubation of vesicles containing SM with acid sphingomyelinase (ASM) (SM phosphodiesterase, EC 3.1.4.12) results in hydrolysis of SM to ceramide (Cer), which enhances cholesterol transfer. Besides SM, ASM also cleaves liposomal phosphatidylcholine. Anionic phospholipids derived from the plasma membrane (phosphatidylglycerol and phosphatidic acid) stimulate SM and phosphatidylcholine hydrolysis by ASM more effectively than BMP, which is generated during endocytosis. ASM-mediated hydrolysis of liposomal SM was also stimulated by incorporation of diacylglycerol (DAG), Cer, and free fatty acids into the liposomal membranes. Conversely, phosphatidylcholine hydrolysis was inhibited by incorporation of cholesterol, Cer, DAG, monoacylglycerol, and fatty acids. Our data suggest that SM degradation by ASM is required for physiological secretion of cholesterol from the late endosomal compartment, and is a key regulator of endolysosomal lipid digestion. PMID:25339683

  13. Copper and zinc induction of lipid peroxidation and effects on antioxidant enzyme activities in the microalga Pavlova viridis (Prymnesiophyceae).

    PubMed

    Li, Mei; Hu, Changwei; Zhu, Qin; Chen, Li; Kong, Zhiming; Liu, Zhili

    2006-01-01

    The metal-induced lipid peroxidation and response of antioxidative enzymes have been investigated in the marine microalga Pavlova viridis to understand the mechanisms of metal resistance in algal cells. We have analyzed superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) activities and glutathione (GSH) contents in microalgal cells grown at different concentrations of copper and zinc. In response to each metal, lipid peroxidation was enhanced with the increase of concentrations, as an indication of the oxidative damage caused by metal concentration assayed in the microalgae cells. Exposure of P. viridis to the two metals caused changes in enzyme activities in a different manner, depending on the metal assayed: after copper treatments, total SOD activity was enhanced, while it was reduced after zinc exposure. Copper and zinc stimulated the activities of CAT and GSH whereas GPX showed a remarkable increase in activity in response to copper treatments and decrease after zinc treatments. These results suggest that an activation of some antioxidant enzymes was enhanced to counteract the oxidative stress induced by the two metals.

  14. Balanced pan-PPAR activator bezafibrate in combination with statin: comprehensive lipids control and diabetes prevention?

    PubMed

    Tenenbaum, Alexander; Fisman, Enrique Z

    2012-11-14

    All fibrates are peroxisome proliferators-activated receptors (PPARs)-alpha agonists with ability to decrease triglyceride and increase high density lipoprotein- cholesterol (HDL-C). However, bezafibrate has a unique characteristic profile of action since it activates all three PPAR subtypes (alpha, gamma and delta) at comparable doses. Therefore, bezafibrate operates as a pan-agonist for all three PPAR isoforms. Selective PPAR gamma agonists (thiazolidinediones) are used to treat type 2 diabetes mellitus (T2DM). They improve insulin sensitivity by up-regulating adipogenesis, decreasing free fatty acid levels, and reversing insulin resistance. However, selective PPAR gamma agonists also cause water retention, weight gain, peripheral edema, and congestive heart failure. The expression of PPAR beta/ delta in essentially all cell types and tissues (ubiquitous presence) suggests its potential fundamental role in cellular biology. PPAR beta/ delta effects correlated with enhancement of fatty acid oxidation, energy consumption and adaptive thermogenesis. Together, these data implicate PPAR beta/delta in fuel combustion and suggest that pan-PPAR agonists that include a component of PPAR beta/delta activation might offset some of the weight gain issues seen with selective PPAR gamma agonists, as was demonstrated by bezafibrate studies. Suggestively, on the whole body level all PPARs acting as one orchestra and balanced pan-PPAR activation seems as an especially attractive pharmacological goal. Conceptually, combined PPAR gamma and alpha action can target simultaneously insulin resistance and atherogenic dyslipidemia, whereas PPAR beta/delta properties may prevent the development of overweight. Bezafibrate, as all fibrates, significantly reduced plasma triglycerides and increased HDL-C level (but considerably stronger than other major fibrates). Bezafibrate significantly decreased prevalence of small, dense low density lipoproteins particles, remnants, induced

  15. Regulation of the high-affinity choline transporter activity and trafficking by its association with cholesterol-rich lipid rafts.

    PubMed

    Cuddy, Leah K; Winick-Ng, Warren; Rylett, Rebecca Jane

    2014-03-01

    The sodium-coupled, hemicholinium-3-sensitive, high-affinity choline transporter (CHT) is responsible for transport of choline into cholinergic nerve terminals from the synaptic cleft following acetylcholine release and hydrolysis. In this study, we address regulation of CHT function by plasma membrane cholesterol. We show for the first time that CHT is concentrated in cholesterol-rich lipid rafts in both SH-SY5Y cells and nerve terminals from mouse forebrain. Treatment of SH-SY5Y cells expressing rat CHT with filipin, methyl-β-cyclodextrin (MβC) or cholesterol oxidase significantly decreased choline uptake. In contrast, CHT activity was increased by addition of cholesterol to membranes using cholesterol-saturated MβC. Kinetic analysis of binding of [(3)H]hemicholinium-3 to CHT revealed that reducing membrane cholesterol with MβC decreased both the apparent binding affinity (KD) and maximum number of binding sites (Bmax ); this was confirmed by decreased plasma membrane CHT protein in lipid rafts in cell surface protein biotinylation assays. Finally, the loss of cell surface CHT associated with lipid raft disruption was not because of changes in CHT internalization. In summary, we provide evidence that CHT association with cholesterol-rich rafts is critical for transporter function and localization. Alterations in plasma membrane cholesterol cholinergic nerve terminals could diminish cholinergic transmission by reducing choline availability for acetylcholine synthesis. The sodium-coupled choline transporter CHT moves choline into cholinergic nerve terminals to serve as substrate for acetylcholine synthesis. We show for the first time that CHT is concentrated in cholesterol-rich lipid rafts, and decreasing membrane cholesterol significantly reduces both choline uptake activity and cell surface CHT protein levels. CHT association with cholesterol-rich rafts is critical for its function, and alterations in plasma membrane cholesterol could diminish cholinergic

  16. Evaluation of antioxidant activity of green tea extract and its effect on the biscuits lipid fraction oxidative stability.

    PubMed

    Mildner-Szkudlarz, S; Zawirska-Wojtasiak, R; Obuchowski, W; Gośliński, M

    2009-10-01

    This article investigates the effect of green tea extract (GTE) on biscuits lipid fraction oxidative stability. The antioxidant activity of GTE was compared with commonly used synthetic antioxidant butylated hydroxyanisole (BHA). Biscuits were prepared in 3 variations. Control samples were prepared without addition of antioxidants. The other variations were prepared by adding BHA (0.02%) and GTE at 3 different levels: 0.02%, 0.1%, and 1%. Biscuits were subjected to sensory studies and instrumental and chemical analysis. Phenolic compounds of GTE characterized powerful antioxidant activities evaluated using free radical, 2,2-diphenyl-1-picrylhydrazyl method, compared with gallic acid and significantly better than BHA. Antioxidants added to the samples clearly slowed down the process of oxidation of fatty acids, inhibiting the monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) decomposition. Addition of GTE at the level of 1% gave an excellent antioxidant effect on the biscuits lipid stability, inhibiting hydroperoxides formation by about 47% to 73% compared with BHA, which showed about 16% to 60% inhibition. However, GTE did not improve significantly lipid stability, measured by anisidine value (p-AV), and inhibited formation of secondary oxidation products only by 3.5%. After accelerated storage time, insensitivity of oxidized-like flavor was about 2 times higher for control samples compared to samples with addition of antioxidants. Moreover, after storage biscuits treated with natural antioxidant received a higher panel score of overall acceptance compared to samples with BHA. Using volatile compound formation as a marker of lipid oxidation, both GTE and BHA were effective inhibitors of the decomposition of hydroperoxides.

  17. Ion transport through lipid bilayers by synthetic ionophores: modulation of activity and selectivity.

    PubMed

    De Riccardis, Francesco; Izzo, Irene; Montesarchio, Daniela; Tecilla, Paolo

    2013-12-17

    The ion-coupled processes that occur in the plasma membrane regulate the cell machineries in all the living organisms. The details of the chemical events that allow ion transport in biological systems remain elusive. However, investigations of the structure and function of natural and artificial transporters has led to increasing insights about the conductance mechanisms. Since the publication of the first successful artificial system by Tabushi and co-workers in 1982, synthetic chemists have designed and constructed a variety of chemically diverse and effective low molecular weight ionophores. Despite their relative structural simplicity, ionophores must satisfy several requirements. They must partition in the membrane, interact specifically with ions, shield them from the hydrocarbon core of the phospholipid bilayer, and transport ions from one side of the membrane to the other. All these attributes require amphipathic molecules in which the polar donor set used for ion recognition (usually oxygens for cations and hydrogen bond donors for anions) is arranged on a lipophilic organic scaffold. Playing with these two structural motifs, donor atoms and scaffolds, researchers have constructed a variety of different ionophores, and we describe a subset of interesting examples in this Account. Despite the ample structural diversity, structure/activity relationships studies reveal common features. Even when they include different hydrophilic moieties (oxyethylene chains, free hydroxyl, etc.) and scaffolds (steroid derivatives, neutral or polar macrocycles, etc.), amphipathic molecules, that cannot span the entire phospholipid bilayer, generate defects in the contact zone between the ionophore and the lipids and increase the permeability in the bulk membrane. Therefore, topologically complex structures that span the entire membrane are needed to elicit channel-like and ion selective behaviors. In particular the alternate-calix[4]arene macrocycle proved to be a versatile

  18. Autophagy Releases Lipid That Promotes Fibrogenesis by Activated Hepatic Stellate Cells in Mice and in Human Tissues

    PubMed Central

    HERNÁNDEZ–GEA, VIRGINIA; GHIASSI–NEJAD, ZAHRA; ROZENFELD, RAPHAEL; GORDON, RONALD; FIEL, MARIA ISABEL; YUE, ZHENYU; CZAJA, MARK J.; FRIEDMAN, SCOTT L.

    2012-01-01

    BACKGROUND & AIMS The pathogenesis of liver fibrosis involves activation of hepatic stellate cells, which is associated with depletion of intracellular lipid droplets. When hepatocytes undergo autophagy, intracellular lipids are degraded in lysosomes. We investigated whether autophagy also promotes loss of lipids in hepatic stellate cells to provide energy for their activation and extended these findings to other fibrogenic cells. METHODS We analyzed hepatic stellate cells from C57BL/6 wild-type, Atg7F/F, and Atg7F/F-GFAP-Cre mice, as well as the mouse stellate cell line JS1. Fibrosis was induced in mice using CCl4 or thioacetamide (TAA); liver tissues and stellate cells were analyzed. Autophagy was blocked in fibrogenic cells from liver and other tissues using small interfering RNAs against Atg5 or Atg7 and chemical antagonists. Human pulmonary fibroblasts were isolated from samples of lung tissue from patients with idiopathic pulmonary fibrosis or from healthy donors. RESULTS In mice, induction of liver injury with CCl4 or TAA increased levels of autophagy. We also observed features of autophagy in activated stellate cells within injured human liver tissue. Loss of autophagic function in cultured mouse stellate cells and in mice following injury reduced fibrogenesis and matrix accumulation; this effect was partially overcome by providing oleic acid as an energy substrate. Autophagy also regulated expression of fibrogenic genes in embryonic, lung, and renal fibroblasts. CONCLUSIONS Autophagy of activated stellate cells is required for hepatic fibrogenesis in mice. Selective reduction of autophagic activity in fibrogenic cells in liver and other tissues might be used to treat patients with fibrotic diseases. PMID:22240484

  19. Effects of intravenous glucose and lipids on innate immune cell activation in healthy, obese, and type 2 diabetic subjects

    PubMed Central

    Horvath, Peter; Oliver, Stacy R; Zaldivar, Frank P; Radom-Aizik, Shlomit; Galassetti, Pietro R

    2015-01-01

    Atherosclerosis/cardiovascular disease are major causes of morbidity/mortality in obesity and type 2 diabetes (T2D), and have been associated with activation of innate immune cells, their diapedesis to the arterial intima and formation of the atherosclerotic plaque. While in obesity/T2D immune cell activation likely depends on dysregulated metabolism, the interaction between individual metabolic factors typical of these conditions (hyperglycemia, hyperlipidemia), innate immune cell activation, and the progression of atherosclerosis remains unclear. We, therefore, measured by flow cytometry cell surface expression of CD11b, CD14, CD16, CD62L, and CD66b, known markers of granulocyte (Gc) and monocyte (Mc) activation, in five healthy, five obese, and five T2D subjects, during 4-h i.v. infusions of 20% dextrose (raising blood sugar levels to ∼220 mg/dL), 20% Intralipid (raising trygliceride levels to ∼6 mmol/L), or a combination of the two. We hypothesized that both glucose and lipids would increase Gc/Mc surface marker expression, and simultaneous infusion would have an additive or synergistic effect. Surprisingly, though, infusion of glucose alone had little effect, while lipids, alone or combined with glucose, significantly increased expression of several markers (such as CD11b in Gc and Mc, and CD66 b in GC) within 60–90 min. Less pronounced increases in systemic inflammatory cytokines also occurred in obese and T2D subject, with no acute changes in gene expression of the the proinflammatory genes NFκB and CCR2. Our results suggest that lipids may be stronger acute contributors to innate cell activation than acute hyperglycemia per se, possibly helping shape more effective preventive dietary guidelines in T2D. PMID:25677544

  20. Modulation of endotoxicity of Shigella generalized modules for membrane antigens (GMMA) by genetic lipid A modifications: relative activation of TLR4 and TLR2 pathways in different mutants.

    PubMed

    Rossi, Omar; Pesce, Isabella; Giannelli, Carlo; Aprea, Susanna; Caboni, Mariaelena; Citiulo, Francesco; Valentini, Sara; Ferlenghi, Ilaria; MacLennan, Calman Alexander; D'Oro, Ugo; Saul, Allan; Gerke, Christiane

    2014-09-05

    Outer membrane particles from Gram-negative bacteria are attractive vaccine candidates as they present surface antigens in their natural context. We previously developed a high yield production process for genetically derived particles, called generalized modules for membrane antigens (GMMA), from Shigella. As GMMA are derived from the outer membrane, they contain immunostimulatory components, especially lipopolysaccharide (LPS). We examined ways of reducing their reactogenicity by modifying lipid A, the endotoxic part of LPS, through deletion of late acyltransferase genes, msbB or htrB, in GMMA-producing Shigella sonnei and Shigella flexneri strains. GMMA with resulting penta-acylated lipid A from the msbB mutants showed a 600-fold reduced ability, and GMMA from the S. sonnei ΔhtrB mutant showed a 60,000-fold reduced ability compared with GMMA with wild-type lipid A to stimulate human Toll-like receptor 4 (TLR4) in a reporter cell line. In human peripheral blood mononuclear cells, GMMA with penta-acylated lipid A showed a marked reduction in induction of inflammatory cytokines (S. sonnei ΔhtrB, 800-fold; ΔmsbB mutants, 300-fold). We found that the residual activity of these GMMA is largely due to non-lipid A-related TLR2 activation. In contrast, in the S. flexneri ΔhtrB mutant, a compensatory lipid A palmitoleoylation resulted in GMMA with hexa-acylated lipid A with ∼10-fold higher activity to stimulate peripheral blood mononuclear cells than GMMA with penta-acylated lipid A, mostly due to retained TLR4 activity. Thus, for use as vaccines, GMMA will likely require lipid A penta-acylation. The results identify the relative contributions of TLR4 and TLR2 activation by GMMA, which need to be taken into consideration for GMMA vaccine development.

  1. Effects of blueberry (Vaccinium ashei) on DNA damage, lipid peroxidation, and phase II enzyme activities in rats.

    PubMed

    Dulebohn, Rachel V; Yi, Weiguang; Srivastava, Anita; Akoh, Casimir C; Krewer, Gerard; Fischer, Joan G

    2008-12-24

    Blueberry extracts have high antioxidant potential and increase phase II enzyme activities in vitro. This study tested the hypothesis that blueberries would reduce DNA damage and lipid peroxidation and increase phase II enzyme activities in vivo. Young, healthy male Sprague-Dawley rats (n = 8 per group) were fed control AIN-93 diets or AIN-93 diets supplemented with blueberries or blueberry extracts for 3 weeks. Diets were supplemented with 10% freeze-dried whole blueberries, blueberry polyphenol extract and sugars to match the 10% blueberry diet, or 1 and 0.2% blueberry flavonoids, which were primarily anthocyanins. Liver and colon mucosa glutathione-S-transferase (GST), quinone reductase, and UDP-glucuronosyltransferase activities in colon mucosa and liver were not significantly increased by freeze-dried whole blueberries or blueberry fractions. Liver GST activity, however, was approximately 25% higher than controls for the freeze-dried whole blueberry, blueberry polyphenol, and 1% flavonoid groups. DNA damage was significantly lower than control only in the liver of animals fed the 1% flavonoid diet. The level of urinary F(2)-isoprostanes, a measure of lipid peroxidation, was unaffected. In summary, in healthy rats, short-term supplementation with freeze-dried whole blueberries, blueberry polyphenols, or blueberry flavonoids did not significantly increase phase II enzyme activities. However, supplementation with 1% blueberry flavonoids did decrease oxidative DNA damage in the liver.

  2. Macrophages enhance the radiosensitizing activity of lipid A: A novel role for immune cells in tumor cell radioresponse

    SciTech Connect

    Ridder, Mark de . E-mail: Mark.De.Ridder@vub.ac.be; Verovski, Valeri N.; Darville, Martine I.; Berge, Dirk L. van den; Monsaert, Christinne; Eizirik, Decio L.; Storme, Guy A.

    2004-10-01

    Purpose: This study examines whether activated macrophages may radiosensitize tumor cells through the release of proinflammatory mediators. Methods and materials: RAW 264.7 macrophages were activated by lipid A, and the conditioned medium (CM) was analyzed for the secretion of cytokines and the production of nitric oxide (NO) through inducible nitric oxide synthase (iNOS). EMT-6 tumor cells were exposed to CM and analyzed for hypoxic cell radiosensitivity. The role of nuclear factor (NF)-{kappa}B in the transcriptional activation of iNOS was examined by luciferase reporter gene assay. Results: Clinical immunomodulator lipid A, at a plasma-relevant concentration of 3 {mu}g/mL, stimulated RAW 264.7 macrophages to release NO, tumor necrosis factor (TNF)-{alpha}, and other cytokines. This in turn activated iNOS-mediated NO production in EMT-6 tumor cells and drastically enhanced their radiosensitivity. Radiosensitization was abrogated by the iNOS inhibitor aminoguanidine but not by a neutralizing anti-TNF-{alpha} antibody. The mechanism of iNOS induction was linked to NF-{kappa}B but not to JAK/STAT signaling. Interferon-{gamma} further increased the NO production by macrophages to a level that caused radiosensitization of EMT-6 cells through the bystanding effect of diffused NO. Conclusions: We demonstrate for the first time that activated macrophages may radiosensitize tumor cells through the induction of NO synthesis, which occurs in both tumor and immune cells.

  3. Nanostructured lipid carriers (NLC) for the delivery of natural molecules with antimicrobial activity: production, characterisation and in vitro studies.

    PubMed

    Cortesi, Rita; Valacchi, Giuseppe; Muresan, Ximena Maria; Drechsler, Markus; Contado, Catia; Esposito, Elisabetta; Grandini, Alessandro; Guerrini, Alessandra; Forlani, Giuseppe; Sacchetti, Gianni

    2017-02-01

    This study describes the preparation, characterisation and in vitro activity of nanostructured lipid carriers (NLCs) encapsulating natural molecules with antimicrobial activity, such as plumbagin, hydroquinon, eugenol, alpha-asarone and alpha-tocopherol. NLCs were prepared by melt and ultrasonication method, characterised by Cryo-TEM for morphology and SdFFF for dimensional distribution and active encapsulation yields. In vitro tests were conducted on bacteria, fungi and human cell cultures. In vitro tests demonstrated that plumbagin is strongly toxic towards F. oxysporum especially when active molecules are loaded on NLC. Plumbagin was completely non toxic on cyanobacterial model strain up to a threshold over which cell viability was completely lost. NLC loaded with active molecules showed a lower toxicity as compared to their free form on human cultured cells. Although further studies need to be performed, these systems can be potentially proposed to control phytopathogenic organisms.

  4. The Hepatitis C Virus-induced NLRP3 Inflammasome Activates the Sterol Regulatory Element-binding Protein (SREBP) and Regulates Lipid Metabolism*

    PubMed Central

    McRae, Steven; Iqbal, Jawed; Sarkar-Dutta, Mehuli; Lane, Samantha; Nagaraj, Abhiram; Ali, Naushad; Waris, Gulam

    2016-01-01

    Hepatitis C virus (HCV) relies on host lipids and lipid droplets for replication and morphogenesis. The accumulation of lipid droplets in infected hepatocytes manifests as hepatosteatosis, a common pathology observed in chronic hepatitis C patients. One way by which HCV promotes the accumulation of intracellular lipids is through enhancing de novo lipogenesis by activating the sterol regulatory element-binding proteins (SREBPs). In general, activation of SREBPs occurs during cholesterol depletion. Interestingly, during HCV infection, the activation of SREBPs occurs under normal cholesterol levels, but the underlying mechanisms are still elusive. Our previous study has demonstrated the activation of the inflammasome complex in HCV-infected human hepatoma cells. In this study, we elucidate the potential link between chronic hepatitis C-associated inflammation and alteration of lipid homeostasis in infected cells. Our results reveal that the HCV-activated NLRP3 inflammasome is required for the up-regulation of lipogenic genes such as 3-hydroxy-3-methylglutaryl-coenzyme A synthase, fatty acid synthase, and stearoyl-CoA desaturase. Using pharmacological inhibitors and siRNA against the inflammasome components (NLRP3, apoptosis-associated speck-like protein containing a CARD, and caspase-1), we further show that the activation of the NLRP3 inflammasome plays a critical role in lipid droplet formation. NLRP3 inflammasome activation in HCV-infected cells enables caspase-1-mediated degradation of insulin-induced gene proteins. This subsequently leads to the transport of the SREBP cleavage-activating protein·SREBP complex from the endoplasmic reticulum to the Golgi, followed by proteolytic activation of SREBPs by S1P and S2P in the Golgi. Typically, inflammasome activation leads to viral clearance. Paradoxically, here we demonstrate how HCV exploits the NLRP3 inflammasome to activate SREBPs and host lipid metabolism, leading to liver disease pathogenesis associated with

  5. The arbuscular mycorrhizal Rhizophagus irregularis activates storage lipid biosynthesis to cope with the benzo[a]pyrene oxidative stress.

    PubMed

    Calonne, Maryline; Fontaine, Joël; Debiane, Djouher; Laruelle, Frédéric; Grandmougin-Ferjani, Anne; Lounès-Hadj Sahraoui, Anissa

    2014-01-01

    The phytoremediation assisted by arbuscular mycorrhizal fungi (AMF) could constitute an ecological and economic method to restore polycyclic aromatic hydrocarbon (PAH) polluted soils. Unfortunately, little is known about the PAH impact on the beneficial symbiotic AMF. Using radiolabelling experiments, our work aims to understand how benzo[a]pyrene (B[a]P), a representative of high molecular weight PAH, acts on the AMF lipid metabolism. Our results showed decreases in the sterol precursors as well as in total phospholipid quantities, in link with the [1-(14)C]acetate incorporation decreases in these lipids. Interestingly, a concomitant increase of [1-(14)C]acetate incorporation by 29.5% into phosphatidylcholine with its content decrease in Rhizophagus irregularis extraradical mycelium was observed, suggesting a membrane regeneration. A second concomitant increase (estimated to 69%) of [1-(14)C]acetate incorporation into triacylglycerols (TAG) with the content decrease was also observed. This suggests a fungal TAG biosynthesis activation probably to offset the decrease in storage lipid content when the fungus was grown under B[a]P pollution. In addition, our findings showed that lipase activity was induced by more than 3 fold in the presence of B[a]P in comparison to the control indicating that the drop in TAG content could be a consequence of their active degradation. Taken together, our data suggest the involvement of the fungal TAG metabolism to cope B[a]P toxicity through two means: (i) by providing carbon skeletons and energy necessary for membrane regeneration and/or for B[a]P translocation and degradation as well as (ii) by activating the phosphatidic acid and hexose metabolisms which may be involved in cellular stress defence.

  6. Lipid metabolism as a target for brain cancer therapy: synergistic activity of lovastatin and sodium phenylacetate against human glioma cells.

    PubMed

    Prasanna, P; Thibault, A; Liu, L; Samid, D

    1996-02-01

    Malignant gliomas, the most common form of primary brain tumors, are highly dependent on the mevalonate (MVA) pathway for the synthesis of lipid moieties critical to cell replication. Human glioblastoma cells were found to be uniquely vulnerable to growth arrest by lovastatin, a competitive inhibitor of the enzyme regulating MVA synthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase. The sodium salt of phenylacetic acid (NaPA), an inhibitor of MVA-pyrophosphate decarboxylase, the enzyme that controls MVA use, acted synergistically with lovastatin to suppress malignant growth. When used at pharmacologically attainable concentrations, the two compounds induced profound cytostasis and loss of malignant properties such as invasiveness and expression of the transforming growth factor-beta 2 gene, coding for a potent immunosuppressive cytokine. Supplementation with exogenous ubiquinone, an end product of the MVA pathway, failed to rescue the cells, suggesting that decreased synthesis of intermediary products are responsible for the antitumor effects observed. In addition to blocking the MVA pathway, lovastatin alone and in combination with NaPA increased the expression of the peroxisome proliferator-activated receptor, a transcription factor implicated in the control of lipid metabolism, cell growth, and differentiation. Our results indicate that targeting lipid metabolism with lovastatin, used alone or in combination with the aromatic fatty acid NaPA, may offer a novel approach to the treatment of malignant gliomas.

  7. Phosphorylated heat shock protein 27 promotes lipid clearance in hepatic cells through interacting with STAT3 and activating autophagy.

    PubMed

    Shen, Lei; Qi, Zhilin; Zhu, Yanyan; Song, Xiaomeng; Xuan, Chunxia; Ben, Peiling; Lan, Lei; Luo, Lan; Yin, Zhimin

    2016-08-01

    Nonalcoholic fatty liver disease (NAFLD) has become the major liver disease worldwide. Recently, several studies have identified that the activation of autophagy attenuates hepatic steatosis. Heat shock protein 27 (Hsp27) is involved in autophagy in response to various stimuli. In this study, we demonstrate that phosphorylated Hsp27 stimulates autophagy and lipid droplet clearance and interacts with STAT3. In vivo study showed that high fat diet (HFD) feeding increased Hsp25 (mouse orthology of Hsp27) phosphorylation and autophagy in mouse livers. Inhibition of Hsp25 phosphorylation exacerbated HFD-induced hepatic steatosis in mice. In vitro study showed that palmitate-induced lipid overload in hepatic cells was enhanced by Hsp27 knockdown, KRIBB3 treatment and Hsp27-3A (non-phosphorylatable) overexpression but was prevented by Hsp27-WT (wild type) and Hsp27-3D (phosphomimetic) overexpression. Mechanism analysis demonstrated that palmitate could induce Hsp27 phosphorylation which promoted palmitate-induced autophagy. Phosphorylated Hsp27 interacted with STAT3 in response to palmitate treatment, and disrupted the STAT3/PKR complexes, facilitated PKR-dependent eIF2α phosphorylation, and thus stimulated autophagy. To conclude, our study provides a novel mechanism by which the phosphorylated Hsp27 promotes hepatic lipid clearance and suggests a new insight for therapy of steatotic diseases such as nonalcoholic fatty liver disease (NAFLD).

  8. The role of sulfatide lipid domains in the membrane pore-forming activity of cobra cardiotoxin.

    PubMed

    Wu, Po-Long; Chiu, Chang-Ru; Huang, Wei-Ning; Wu, Wen-Guey

    2012-05-01

    Cobra CTX A3, the major cardiotoxin (CTX) from Naja atra, is a cytotoxic, basic β-sheet polypeptide that is known to induce a transient membrane leakage of cardiomyocytes through a sulfatide-dependent CTX membrane pore formation and internalization mechanism. The molecular specificity of CTX A3-sulfatide interaction at atomic levels has also been shown by both nuclear magnetic resonance (NMR) and X-ray diffraction techniques to reveal a role of CTX-induced sulfatide conformational changes for CTX A3 binding and dimer formation. In this study, we investigate the role of sulfatide lipid domains in CTX pore formation by various biophysical methods, including fluorescence imaging and atomic force microscopy, and suggest an important role of liquid-disordered (ld) and solid-ordered (so) phase boundary in lipid domains to facilitate the process. Fluorescence spectroscopic studies on the kinetics of membrane leakage and CTX oligomerization further reveal that, although most CTXs can oligomerize on membranes, only a small fraction of CTXs oligomerizations form leakage pores. We therefore suggest that CTX binding at the boundary between the so and so/ld phase coexistence sulfatide lipid domains could form effective pores to significantly enhance the CTX-induced membrane leakage of sulfatide-containing phosphatidylcholine vesicles. The model is consistent with our earlier observations that CTX may penetrate and lyse the bilayers into small aggregates at a lipid/protein molar ratio of about 20 in the ripple P(β)' phase of phosphatidylcholine bilayers and suggest a novel mechanism for the synergistic action of cobra secretary phospholipase A2 and CTXs.

  9. Lipid lateral heterogeneity in phosphatidylcholine/phosphatidylserine/diacylglycerol vesicles and its influence on protein kinase C activation.

    PubMed Central

    Dibble, A R; Hinderliter, A K; Sando, J J; Biltonen, R L

    1996-01-01

    To test the hypothesis that the activation of protein kinase C (PKC) is influenced by lateral heterogeneities of the components of the lipid bilayer, the thermotropic phase behavior of dimyristoylphosphatidylcholine (DMPC)/dimyristoylphosphatidylserine (DMPS)/dioleoylglycerol (DO) vesicles was compared with the activation of PKC by this system. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to monitor the main transition (i.e., the gel-to-fluid phase transition) as a function of mole fraction DO (chi(DO)) in DMPC/DO, DMPS/DO, and [DMPC/DMPS (1:1, mol/mol)]/DO multilamellar vesicles (MLVs). In each case, when chi(DO) < or approximately 0.3, DO significantly broadened the main transition and shifted it to lower temperatures; but when chi(DO) > approximately 0.3, the main transition became highly cooperative, i.e., narrow, again. The coexistence of overlapping narrow and broad transitions was clearly evident in DSC thermograms from chi(DO) approximately 0.1 to chi(DO) approximately 0.3, with the more cooperative transition growing at the expense of the broader one as chi(DO) increased. FTIR spectroscopy, using analogs of DMPC and DMPS with perdeuterated acyl chains, showed that the melting profiles of all three lipid components in [DMPC/DMPS (1:1, mol/mol)]/DO MLVs virtually overlay when chi(DO) = 0.33, suggesting that a new type of phase, with a phospholipid/DO mole ratio near 2:1, is formed in this system. Collectively, the results are consistent with the coexistence of DO-poor and DO-rich domains throughout the compositions chi(DO) approximately 0.1 to chi(DO) approximately 0.3, even at temperatures above the main transition. Comparison of the phase behavior of the binary mixtures with that of the ternary mixtures suggests that DMPS/DO interactions may be more favorable than DMPC/DO interactions in the ternary system, especially in the gel state. PKC activity was measured using [DMPC/DMPS (1:1, mol/mol)]/DO MLVs

  10. [Effects of exogenous spermidine on lipid peroxidation and membrane proton pump activity of cucumber seedling leaves under high temperature stress].

    PubMed

    Tian, Jing; Guo, Shi-Rong; Sun, Jin; Wang, Li-Ping; Yang, Yan-Juan; Li, Bin

    2011-12-01

    Taking a relatively heat-resistant cucumber (Cucumis sativus) cultivar 'Jinchun No. 4' as test material, a sand culture experiment was conducted in growth chamber to investigate the effects of foliar spraying spermidine (Spd) on the lipid peroxidation, membrane proton pump activity, and corresponding gene expression of cucumber seedling leaves under high temperature stress. Compared with the control, foliar spraying Spd increased the plant height, stem diameter, dry and fresh mass, and leaf area significantly, and inhibited the increase of leaf relative conductivity, malondialdehyde (MDA) content, and lipoxygenase (LOX) activity effectively. Foliar spraying Spd also helped to the increase of leaf plasma membrane- and tonoplast H(+)-ATPase activity, but no significant difference was observed in the gene expression levels. These results suggested that exogenous Spd could significantly decrease the leaf lipid peroxidation and increase the proton pump activity, and thus, stabilize the leaf membrane structure and function, alleviate the damage induced by high temperature stress, and enhance the heat tolerance of cucumber seedlings.

  11. Structure activity characterization of Bordetella petrii lipid A, from environment to human isolates.

    PubMed

    Basheer, Soorej M; Bouchez, Valerie; Novikov, Alexey; Augusto, Luis A; Guiso, Nicole; Caroff, Martine

    2016-01-01

    Bordetella petrii, a facultative anaerobic species, is the only known member of the Bordetella genus with environmental origin. However it was also recently isolated from humans. The structures of the B. petrii lipid A moieties of the endotoxins were characterized here for the first time for an environmental strain and compared to that of human isolates. Characterization was achieved using chemical analyses, gas chromatography-mass spectrometry, and Matrix Assisted Laser Desorption Ionisation mass spectrometry. The analyses revealed that the different lipid A structures contain a common bisphosphorylated β-(1→6)-linked d-glucosamine disaccharide with hydroxytetradecanoic acid in amide as well at the C-3' in ester linkages. Similar to Bordetella pertussis and Bordetella bronchiseptica lipids A, the hydroxytetradecanoic acid at the C-2' position was substituted by tetradecanoic acid. Unlike B. pertussis, the hydroxytetradecanoic acid at the C-2 position was substituted with either 12:0 or 14:0 and/or their 2-OH forms. Depending on the environmental or human origin the structures differed in the length and degree of fatty acid acylation and impacted the IL-6 and TNF-α inflammatory responses tested. In one isolate we showed the presence at the C-3 position of the short-chain 10:0(3-OH), which according to our previous analyses is more characteristic of the human pathogens in the genus like B. pertussis and Bordetella parapertussis.

  12. Sesame lignans enhance antioxidant activity of vitamin E in lipid peroxidation systems.

    PubMed

    Ghafoorunissa; Hemalatha, S; Rao, M Vishnu Vardhana

    2004-07-01

    The antioxidant properties of sesame lignans (sesamol, sesamin and sesamolin) were evaluated in comparison to tocols (alpha- and gamma-tocopherols and alpha-tocotrienol) and butylated hydroxytoluene (BHT) using the following in vitro lipid peroxidation systems: (i) rat liver microsomes and cumene hydroperoxide (CumOOH)/Fe2+-ADP-NADPH (enzymatic) or (ii) rat liver mitochondria and Fe2+-ascorbate (nonenzymatic) systems. Sesamol containing a free phenolic group inhibited lipid peroxidation in both the systems whereas sesamin and sesamolin having methylenedioxy groups were effective only in the microsomal system. Since detoxifying enzymes are localized in microsomes, the inhibitory effects of sesamin and sesamolin observed in the microsomal system may be attributed to their metabolites. However, the inhibitory effects of lignans were lower than tocols and BHT. Combination of individual lignans and tocopherols (alpha, gamma) or alpha-tocotrienol showed higher inhibitory effects than the sum of individual inhibitions in CumOOH and Fe2+-ascorbate systems suggesting synergistic interactions. The time course of CumOOH-mediated lipid peroxidation showed a lag period and a decreased rate of thiobarbituric acid reactive product formation in the presence of individual lignans in combination with alpha-tocopherol suggesting recycling of alpha-tocopherol.

  13. Piperidine alkaloids from Piperretrofractum Vahl. protect against high-fat diet-induced obesity by regulating lipid metabolism and activating AMP-activated protein kinase

    SciTech Connect

    Kim, Kyung Jin; Lee, Myoung-Su; Jo, Keunae; Hwang, Jae-Kwan

    2011-07-22

    Highlights: {yields} Piperidine alkaloids from Piperretrofractum Vahl. (PRPAs), including piperine, pipernonaline, and dehydropipernonaline, are isolated as the anti-obesity constituents. {yields} PRPA administration significantly reduces body weight gain without altering food intake and fat pad mass. {yields} PRPA reduces high-fat diet-induced triglyceride accumulation in liver. {yields} PRPAs attenuate HFD-induced obesity by activating AMPK and PPAR{delta}, and regulate lipid metabolism, suggesting their potential anti-obesity effects. -- Abstract: The fruits of Piperretrofractum Vahl. have been used for their anti-flatulent, expectorant, antitussive, antifungal, and appetizing properties in traditional medicine, and they are reported to possess gastroprotective and cholesterol-lowering properties. However, their anti-obesity activity remains unexplored. The present study was conducted to isolate the anti-obesity constituents from P. retrofractum Vahl. and evaluate their effects in high-fat diet (HFD)-induced obese mice. Piperidine alkaloids from P. retrofractum Vahl. (PRPAs), including piperine, pipernonaline, and dehydropipernonaline, were isolated as the anti-obesity constituents through a peroxisome proliferator-activated receptor {delta} (PPAR{delta}) transactivation assay. The molecular mechanism was investigated in 3T3-L1 adipocytes and L6 myocytes. PRPA treatment activated AMP-activated protein kinase (AMPK) signaling and PPAR{delta} protein and also regulated the expression of lipid metabolism-related proteins. In the animal model, oral PRPA administration (50, 100, or 300 mg/kg/day for 8 weeks) significantly reduced HFD-induced body weight gain without altering the amount of food intake. Fat pad mass was reduced in the PRPA treatment groups, as evidenced by reduced adipocyte size. In addition, elevated serum levels of total cholesterol, low-density lipoprotein cholesterol, total lipid, leptin, and lipase were suppressed by PRPA treatment. PRPA also

  14. Resveratrol prevents the impairment of advanced glycosylation end products (AGE) on macrophage lipid homeostasis by suppressing the receptor for AGE via peroxisome proliferator-activated receptor gamma activation.

    PubMed

    Zhang, Yihua; Luo, Zhidan; Ma, Liqun; Xu, Qiang; Yang, Qihong; Si, Liangyi

    2010-05-01

    Advanced glycosylation end products (AGE) and its receptor (RAGE) axis is involved in the regulation of lipid homeostasis and is critical in the pathogenesis of diabetic atherosclerosis. We investigated the protective role of resveratrol against the AGE-induced impairment on macrophage lipid homeostasis. In THP-1-derived macrophages, RAGE was dose-dependently induced by AGE and played a key role in the AGE-induced cholesterol accumulation. Resveratrol markedly reduced RAGE expression via peroxisome proliferator-activated receptor (PPAR) gamma but not PPARalpha or AMP-activated protein kinase. Importantly, pretreatment with resveratrol significantly ameliorated AGE-induced up-regulation of scavenger receptor-A (SR-A) and down-regulation of ATP-binding cassette (ABC) A1 and ABCG1 and thus effectively prevented the cholesterol accumulation in macrophages as shown by cellular cholesterol analysis and oil red O staining. Moreover, blockade of PPARgamma abolished all these effects of resveratrol. Collectively, our results indicate that resveratrol prevents the impairment of AGE on macrophage lipid homeostasis partially by suppressing RAGE via PPARgamma activation, which might provide new insight into the protective role of resveratrol against diabetic atherosclerosis.

  15. Dietary antioxidant supplementation enhances lipid and protein oxidative stability of chicken broiler meat through promotion of antioxidant enzyme activity.

    PubMed

    Delles, Rebecca M; Xiong, Youling L; True, Alma D; Ao, Touying; Dawson, Karl A

    2014-06-01

    Recent nutrigenomic studies have shown that animal nutrition can have a major influence on tissue gene expression. Dietary antioxidant supplements can enhance the quality of meat through modification of tissue metabolic processes. This study investigated the influence of dietary antioxidants and quality of oil on the oxidative and enzymatic properties of chicken broiler breast meat stored in an oxygen-enriched package (HiOx: 80% O2/20% CO2) in comparison with air-permeable polyvinylchloride (PVC) or skin packaging systems during retail display at 2 to 4°C for up to 21 d. Broilers were fed either a diet with a low-oxidized (peroxide value 23 mEq of O2/kg) or high-oxidized (peroxide value 121 mEq of O2/kg) oil, supplemented with or without an algae-based Se yeast and organic mineral antioxidant pack for 42 d. Lipid and protein oxidation and tissue enzymatic activity were analyzed. In all packaging systems, lipid oxidation (TBA reactive substances) was inhibited by up to 32.5% (P < 0.05) with an antioxidant-supplemented diet when compared with diets without antioxidants, particularly in the HiOx and PVC systems. Protein sulfhydryls were significantly protected by antioxidant diets (e.g., by 14.6 and 17.8% for low-and high-oxidized dietary groups, respectively, in PVC d 7 samples). Glutathione peroxidase, catalase, and superoxide dismutase activities were significantly higher (P < 0.05) in antioxidant-supplemented diets compared with the basal diet, regardless of oil quality. Also, serum carbonyls were lower in broilers fed a low-oxidized antioxidant-supplemented treatment. The results demonstrate that dietary antioxidants can minimize the oxidative instability of proteins and lipids, and the protection may be linked to improved cellular antioxidant enzymatic activity.

  16. Dietary antioxidant supplementation enhances lipid and protein oxidative stability of chicken broiler meat through promotion of antioxidant enzyme activity1

    PubMed Central

    Delles, Rebecca M.; Xiong, Youling L.; True, Alma D.; Ao, Touying; Dawson, Karl A.

    2014-01-01

    Recent nutrigenomic studies have shown that animal nutrition can have a major influence on tissue gene expression. Dietary antioxidant supplements can enhance the quality of meat through modification of tissue metabolic processes. This study investigated the influence of dietary antioxidants and quality of oil on the oxidative and enzymatic properties of chicken broiler breast meat stored in an oxygen-enriched package (HiOx: 80% O2/20% CO2) in comparison with air-permeable polyvinylchloride (PVC) or skin packaging systems during retail display at 2 to 4°C for up to 21 d. Broilers were fed either a diet with a low-oxidized (peroxide value 23 mEq of O2/kg) or high-oxidized (peroxide value 121 mEq of O2/kg) oil, supplemented with or without an algae-based Se yeast and organic mineral antioxidant pack for 42 d. Lipid and protein oxidation and tissue enzymatic activity were analyzed. In all packaging systems, lipid oxidation (TBA reactive substances) was inhibited by up to 32.5% (P < 0.05) with an antioxidant-supplemented diet when compared with diets without antioxidants, particularly in the HiOx and PVC systems. Protein sulfhydryls were significantly protected by antioxidant diets (e.g., by 14.6 and 17.8% for low-and high-oxidized dietary groups, respectively, in PVC d 7 samples). Glutathione peroxidase, catalase, and superoxide dismutase activities were significantly higher (P < 0.05) in antioxidant-supplemented diets compared with the basal diet, regardless of oil quality. Also, serum carbonyls were lower in broilers fed a low-oxidized antioxidant-supplemented treatment. The results demonstrate that dietary antioxidants can minimize the oxidative instability of proteins and lipids, and the protection may be linked to improved cellular antioxidant enzymatic activity. PMID:24879706

  17. Serum biochemical profile, enzymatic activity and lipid peroxidation in organs of laying hens fed diets containing cashew nut shell liquid.

    PubMed

    Braz, N M; Freitas, E R; Trevisan, M T S; do Nascimento, G A J; Salles, R P R; Cruz, C E B; Farias, N N P; da Silva, I N G; Watanabe, P H

    2017-03-16

    The objective of this study was to evaluate the effect of feeding laying hens diets containing cashew nut shell liquid (CNSL) as a source of anacardic acid on the blood biochemical parameters as well as the enzymatic activity and lipid peroxidation of liver and tissues of the reproductive system (ovary, magnum, and uterus). A total of 216 Hisex White commercial laying hens were distributed randomly into six treatments, with six replicates of six birds. Treatments consisted of a diet without growth promoter (GP); a diet with GP; and diets without GP, with addition of increasing levels of CNSL (0.25, 0.50, 0.75 and 1.0%). Addition of CNSL to the diet did not affect the blood biochemical parameters (uric acid, creatinine, alanine aminotransferase, aspartate aminotransferase, total cholesterol, high density lipoproteins, low-density lipoproteins and triglycerides), the enzymatic activity (superoxide dismutase and nonprotein sulphydryl groups) in the organs (liver, ovary, magnum and uterus) or the peroxidation of lipids from the blood serum, liver, magnum and uterus (p > 0.05). However, the addition of 0.75% and 1.00% CNSL provided a lower thiobarbituric acid reactive substances content in the birds' ovary (p < 0.001) compared to birds of other treatments, whereas the treatment without the GP provided a higher value. Addition of up to 1% of the CNSL as a source of anacardic acid in the laying hens' diets does not influence blood biochemical parameters or the endogenous enzymatic activity in the liver, ovary, magnum and uterus, but affects the lipid peroxidation in the ovary, although the problem is reduced from the inclusion of 0.75% CNSL.

  18. Smoke exposure causes endoplasmic reticulum stress and lipid accumulation in retinal pigment epithelium through oxidative stress and complement activation.

    PubMed

    Kunchithapautham, Kannan; Atkinson, Carl; Rohrer, Bärbel

    2014-05-23

    Age-related macular degeneration (AMD) is a complex disease caused by genetic and environmental factors, including genetic variants in complement components and smoking. Smoke exposure leads to oxidative stress, complement activation, endoplasmic reticulum (ER) stress, and lipid dysregulation, which have all been proposed to be associated with AMD pathogenesis. Here we examine the effects of smoke exposure on the retinal pigment epithelium (RPE). Mice were exposed to cigarette smoke or filtered air for 6 months. RPE cells grown as stable monolayers were exposed to 5% cigarette smoke extract (CSE). Effects of smoke were determined by biochemical, molecular, and histological measures. Effects of the alternative pathway (AP) of complement and complement C3a anaphylatoxin receptor signaling were analyzed using knock-out mice or specific inhibitors. ER stress markers were elevated after smoke exposure in RPE of intact mice, which was eliminated in AP-deficient mice. To examine this relationship further, RPE monolayers were exposed to CSE. Short term smoke exposure resulted in production and release of complement C3, the generation of C3a, oxidative stress, complement activation on the cell membrane, and ER stress. Long term exposure to CSE resulted in lipid accumulation, and secretion. All measures were reversed by blocking C3a complement receptor (C3aR), alternative complement pathway signaling, and antioxidant therapy. Taken together, our results provide clear evidence that smoke exposure results in oxidative stress and complement activation via the AP, resulting in ER stress-mediated lipid accumulation, and further suggesting that oxidative stress and complement act synergistically in the pathogenesis of AMD.

  19. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-02

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  20. Brown bears (Ursus arctos) seem resistant to atherosclerosis despite highly elevated plasma lipids during hibernation and active state.

    PubMed

    Arinell, Karin; Sahdo, Berolla; Evans, Alina L; Arnemo, Jon M; Baandrup, Ulrik; Fröbert, Ole

    2012-06-01

    Hibernation is an extreme physiological challenge for the brown bear (Ursus arctos) in which metabolism is based mainly on lipids. The study objective was to compare plasma lipids in hibernating and active free-ranging brown bears and relate them to arterial histopathology. Blood was drawn from seven immobilized free-ranging brown bears (three females, 2-3 years old) during hibernation in February and from the same bears while active in June and analyzed by enzymatic and automated hematology methods within 48 hours of sampling. Left anterior descending coronary arteries and aortic arches from 12 bears (six females, 1.5-12 years old) killed in hunting were examined by histopathology. Total plasma cholesterol decreased from hibernation to the active period (11.08 ± 1.04 mmol/L vs. 7.89 ± 1.96 mmol/L, P= 0.0028) as did triglyceride (3.16 ± 0.62 mmol/L vs. 1.44 ± 0.27 mmol/L, P= 0.00012) and LDL cholesterol (4.30 ± 0.71 mmol/L vs. 2.02 ± 1.03 mmol/L, P= 0.0075), whereas HDL cholesterol was unchanged. No atherosclerosis, fatty streaks, foam cell infiltration, or inflammation were seen in any arterial samples. Brown bears tolerate elevated cholesterol levels, obesity, physical inactivity, and circulatory slow flow during hibernation without signs of -atherosclerosis. This species might serve as a reverse translational model for atherosclerosis resistance.

  1. Influence of arbuscular mycorrhiza on lipid peroxidation and antioxidant enzyme activity of maize plants under temperature stress.

    PubMed

    Zhu, Xiancan; Song, Fengbin; Xu, Hongwen

    2010-06-01

    The influence of the arbuscular mycorrhizal (AM) fungus, Glomus etunicatum, on characteristics of growth, membrane lipid peroxidation, osmotic adjustment, and activity of antioxidant enzymes in leaves and roots of maize (Zea mays L.) plants was studied in pot culture under temperature stress. The maize plants were placed in a sand and soil mixture under normal temperature for 6 weeks and then exposed to five different temperature treatments (5 degrees C, 15 degrees C, 25 degrees C, 35 degrees C, and 40 degrees C) for 1 week. AM symbiosis decreased membrane relative permeability and malondialdehyde content in leaves and roots. The contents of soluble sugar content and proline in roots were higher, but leaf proline content was lower in mycorrhizal than nonmycorrhizal plants. AM colonization increased the activities of superoxide dismutase, catalase, and peroxidase in leaves and roots. The results indicate that the AM fungus is capable of alleviating the damage caused by temperature stress on maize plants by reducing membrane lipid peroxidation and membrane permeability and increasing the accumulation of osmotic adjustment compounds and antioxidant enzyme activity. Consequently, arbuscular mycorrhiza formation highly enhanced the extreme temperature tolerance of maize plant, which increased host biomass and promoted plant growth.

  2. Curcumin Blocks Naproxen-Induced Gastric Antral Ulcerations through Inhibition of Lipid Peroxidation and Activation of Enzymatic Scavengers in Rats.

    PubMed

    Kim, Jeong-Hwan; Jin, Soojung; Kwon, Hyun Ju; Kim, Byung Woo

    2016-08-28

    Curcumin is a polyphenol derived from the plant Curcuma longa, which is used for the treatment of diseases associated with oxidative stress and inflammation. The present study was undertaken to determine the protective effect of curcumin against naproxen-induced gastric antral ulcerations in rats. Different doses (10, 50, and 100 mg/kg) of curcumin or vehicle (curcumin, 0 mg/kg) were pretreated for 3 days by oral gavage, and then gastric mucosal lesions were caused by 80 mg/kg naproxen applied for 3 days. Curcumin significantly inhibited the naproxen-induced gastric antral ulcer area and lipid peroxidation in a dose-dependent manner. In addition, curcumin markedly increased activities of radical scavenging enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase in a dose-dependent manner. Specifically, 100 mg/kg curcumin completely protected the gastric mucosa against the loss in the enzyme, resulting in a drastic increase of activities of radical scavenging enzymes up to more than the level of untreated normal rats. Histological examination obviously showed that curcumin prevents naproxen-induced gastric antral ulceration as a result of direct protection of the gastric mucosa. These results suggest that curcumin blocks naproxen-induced gastric antral ulcerations through prevention of lipid peroxidation and activation of radical scavenging enzymes, and it may offer a potential remedy of gastric antral ulcerations.

  3. Prospective associations among cereal intake in childhood and adiposity, lipid levels, and physical activity during late adolescence.

    PubMed

    Albertson, Ann M; Thompson, Douglas; Franko, Debra L; Holschuh, Norton M; Bauserman, Robert; Barton, Bruce A

    2009-10-01

    Cereal consumption is a common dietary behavior that has been associated with positive health outcomes. The objective of this study was to examine prospective associations between cereal intake in childhood and percent body fat, waist-to-hip ratio, lipid levels, and physical activity during late adolescence. In this longitudinal investigation (data collected 1987-1997), data were analyzed for the 2,379 girls who participated in the 10-year National Heart, Lung, and Blood Institute Growth and Health Study. The cumulative percent of days that each girl consumed cereal during childhood (based on 3-day food diaries collected during six study visits between ages 11.5 and 18.6 years) was examined in relation to percent body fat, waist-to-hip ratio, lipid levels, and physical activity measured at age 18.6 years. Results indicated that nearly all girls (90.1%) reported eating cereal and 18.7% reported eating cereal on half or more of the days reported in the food diaries. Girls who ate cereal on a greater percentage of days during childhood had lower percent body fat and total cholesterol, and were more likely to exhibit high levels of physical activity and less television viewing during Study Year 10 (P values<0.05). Further research should explore lifestyle issues related to cereal consumption.

  4. [Anti-radical activity of products of processing of holothurian Cucumaria japonica and their practical application for lipid stabilization].

    PubMed

    Tabakaeva, O V; Kalenik, T K; Tabakaev, A V

    2015-01-01

    Products of technological and biotechnological modification (acid and enzymatic hydrolyzates and hydrothermal extracts) of the holothurian Cucumariajaponica from the Far East region are the complex multicomponent systems containing biologically active agents of a sea origin that has to provide them biological activity. The research objective consisted in quantitative studying of anti-radical properties of acid, enzymatic hydrolyzates and hydrothermal extracts from soft fabrics of a holothurian from the Far East region (Cucumaria japonica) and their influence on oxidation of lipids in fat emulsion products. The reaction with stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was used as a model system. Radical relating activity of hydrolyzates and extracts from Cucumaria japonica varied over a wide range from 48 to 78%. The maximum radical binding activity was noted for acid hydrolyzates. The activity of the hydrolyzate from a nimbus and feelers of Cucumaria japonica was comparable with activity of ionol. It has been defined that levels of manifestation of anti-radical activity depended on a way of technological and biotechnological processing of raw materials. Studying of fractional composition of melanoidins of hydrolyzates and extracts from Cucumaria japonica established that they can be divided into fractions--with molecular masses about 10,000 and 1000 Da. The maximum content of melanoidins has been defined in fraction weighing about 1000 Da. Introduction of acid, enzymatic hydrolyzates and hydrothermal extracts from Cucumaria japonica in the composition of oil-fat emulsion systems allowed to slow down processes of lipid oxidation and triglyceride hydrolysis in mayonnaise. Introduction of hydrolyzates and hydrothermal extracts from Cucumaria japonica in an oil-fat emulsion product allowed to reduce peroxide value by 22-45%, acid value by 12-35% on the 90th days of storage. Acid hydrolysates of Cucumaria Japonica most significantly reduce the rate of

  5. Salinity stress increases lipid, secondary metabolites and enzyme activity in Amphora subtropica and Dunaliella sp. for biodiesel production.

    PubMed

    BenMoussa-Dahmen, Ines; Chtourou, Haifa; Rezgui, Fatma; Sayadi, Sami; Dhouib, Abdelhafidh

    2016-10-01

    Amphora subtropica and Dunaliella sp. isolated from Tunisian biotopes were retained for their high lipid contents. Respective optimized parameters for rapid growth were: pH 9 and 10, light period 21 and 24h and temperature 31 and 34°C, respectively. After optimization, Amphora subtropica growth rate increased from 0.2 to 0.5day(-1) and Dunaliella sp. growth rate increased from 0.38 to 0.7day(-1). Amphora subtropica biomass production, productivity and lipid content increased from 0.3 to 0.7gL(-1)(dw), 69-100mgL(-1)d(-1)(dw) and 150-190gkg(-1)(dw), respectively, and Dunaliella sp. from 0.5 to 1.4gL(-1)(dw), 124-200mgL(-1)d(-1) (dw) and 190-280gkg(-1)(dw), respectively. Often to overcome trade-off between microalgae rapid growth and high lipid content which are often conflicting and very difficult to obtain at the same time, separation in a growth stage and a lipid accumulation stage is obvious. Salinity stress in a single stage of culture was studied. Compared to the optimal concentration of growth, excess or deficiency of NaCl engendered the same cellular responses by implication of oxidative stress systems and reactivation of defense and storage systems. Indeed, increasing salinity from 1M to 2M for Amphora subtropica or decreasing salinity from 3M to 2M for Dunaliella sp. have both increased lipids content from (220 and 280) to (350 and 430)gkg(-1), carotenoids from (1.8 and 2.4) to (2.3 and 3.7)pgcell(-1), TBARS amount from (10.4 and 5.3) to (12.1 and 10.7)nmolmg(-1) proteins and SOD activity from of (46.6 and 61.8) to (71.6 and 79.4)Umg(-1) proteins, respectively. With further improved fatty acids profile, the microalgae strains could be potent candidates for biofuel production.

  6. Antifungal activity of Zataria multiflora essential oil-loaded solid lipid nanoparticles in-vitro condition

    PubMed Central

    Nasseri, Mahboobeh; Golmohammadzadeh, Shiva; Arouiee, Hossein; Jaafari, Mahmoud Reza; Neamati, Hossein

    2016-01-01

    Objective(s): The aim of the present study was to prepare, characterize, and evaluate solid lipid nanoparticles (SLNs) containing Zataria multiflora essential oil (ZEO). Materials and Methods: In this study, Z. multiflora essential oil-loaded solid lipid nanoparticles (ZE-SLNs) were prepared to improve its efficiency in controlling some fungal pathogens. SLNs containing Z. multiflora essential oil were prepared by high shear homogenization and ultra sound technique. ZEO-SLNs contained 0.03% ZEO in 5% of lipid phase (Glyceryl monostearate-GMS and Precirol® ATO 5). Tween 80 and Poloxamer 188 (2.5% w/v) were used as surfactant in the aqueous phase. The antifungal efficacy of ZE-SLNs and ZEO was compared under in vitro conditions. Results: The particle size of ZE-SLNs was around 255.5±3 nm with PDI of 0.369±0.05 and zeta potential was about -37.8±0.8 mV. Encapsulation efficacy of ZE-SLNs in crystalline form was 84±0.92%. The results showed that the ZEO and ZE-SLNs had 54 and 79% inhibition on the growth of fungal pathogens, respectively. The minimum inhibitory concentration (MIC) under in vitro conditions for the ZEO on the fungal pathogens of Aspergillus ochraceus, Aspergillus niger, Aspergillus flavus, Alternaria solani, Rhizoctonia solani, and Rhizopus stolonifer was 300, 200, 300, 200, 200 and 200 ppm, respectively, for ZE-SLNs, it was 200, 200, 200, 100, 50 and 50 ppm. The antifungal efficacy of ZE-SLNs was significantly more than ZEO. Conclusion: Our results showed that the SLNs were suitable carriers for Z. multiflora essential oil in controlling the fungal pathogens and merits further investigation. PMID:27917280

  7. Enhanced in Vitro Anti-Tumor Activity of 5-Azacytidine by Entrapment into Solid Lipid Nanoparticles

    PubMed Central

    Jahanfar, Farhad; Hasani, Akbar; Shanebandi, Dariush; Rahmati, Mohammad; Hamishehkar, Hamed

    2016-01-01

    Purpose: In this study the effectiveness of encapsulating of 5-azacytidine into the lipid nanoparticles was investigated and in vitro effect of encapsulated 5-azacytidine studied on MCF-7 cell lines Methods: 5-azacytidine -loaded solid lipid nanoparticles were produced by double emulsification (w/o/w) method by using stearic acid as lipid matrix, soy lecithin and poloxamer 407 as surfactant and co-surfactant respectively. Particle size, zeta potential, surface morphology, entrapment efficiency and kinetic of drug release were studied. In vitro effect of 5-azacytidine on MCF-7 cell line studied by MTT assay, DAPI staining, Rhodamine B relative uptake, and also Real time RT-PCR was performed for studying difference effect of free and encapsulated drug on expression of RARß2 gene. Results: The formulation F5 with 55.84±0.46 % of entrapment efficiency shows zero order kinetic of drug release and selected for in vitro studies; the cytotoxicity of free drug and encapsulated drug in 48 h of incubation have significant difference. DAPI staining shows morphology of apoptotic nucleus in both free and encapsulated drug, Rhodamine B labeled SLNs show time dependency and accumulation of SLNs in cytoplasm. Real time qRT-PCR doesn’t show any significant difference (p>0.05) in expression of RARß2 gene in both cells treated with free or encapsulated drug. Conclusion: The results of the present study indicated that the entrapment of 5-azacytidine into SLNs enhanced its cytotoxicity performance and may pave a way for the future design of a desired dosage form for 5-azacytidine. PMID:27766220

  8. Folate-targeted docetaxel-lipid-based-nanosuspensions for active-targeted cancer therapy

    PubMed Central

    Wang, Lili; Li, Min; Zhang, Na

    2012-01-01

    The purpose of this study was to develop two novel drug delivery systems based on biodegradable docetaxel-lipid-based-nanosuspensions. The first one was poly(ethylene glycol)- modified docetaxel-lipid-based-nanosuspensions (pLNS). It was developed to increase the cycle time of the drug within the body and enhance the accumulation of the drug at the tumor site. The second one was targeted docetaxel-lipid-based-nanosuspensions (tLNS) using folate as the target ligand. The tLNS could target the tumor cells that overexpressed folate receptor (FR). The morphology, particle size, and zeta potential of pLNS and tLNS were characterized, respectively. The in vitro cytotoxicity evaluation of Duopafei®, pLNS, and tLNS were performed in human hepatocellular liver carcinoma HepG2 (FR−) and B16 (FR+) cells, respectively. The in vivo antitumor efficacy and pharmacokinetics, as well as the drug tissue distribution, were evaluated in Kunming mice bearing B16 cells. The particle size of pLNS was 204.2 ± 6.18 nm and tLNS had a mean particle size of 220.6 ± 9.54 nm. Cytotoxicity of tLNS against B16 (FR+) cell lines was superior to pLNS (P < 0.05), while there was no significant difference in the half maximum inhibitory concentration values for HepG2 (FR−) cells between pLNS and tLNS. The results of the in vivo antitumor efficacy evaluation showed that tLNS exhibited higher antitumor efficacy by reducing tumor volume (P < 0.01) compared with Duopafei and pLNS, respectively. The results of the in vivo biodistribution study indicate that the better antitumor efficacy of tLNS was attributed to the increased accumulation of the drug in the tumor. PMID:22802688

  9. CD169+ MACROPHAGES PRESENT LIPID ANTIGENS TO MEDIATE EARLY ACTIVATION OF INVARIANT NKT CELLS IN LYMPH NODES

    PubMed Central

    Barral, Patricia; Polzella, Paolo; Bruckbauer, Andreas; van Rooijen, Nico; Besra, Gurdyal S.; Cerundolo, Vincenzo; Batista, Facundo D.

    2010-01-01

    Invariant NKT (iNKT) cells are involved in host defence against microbial infections. While it is known that iNKT cells recognize glycolipids presented by CD1d, how and where they encounter antigen in vivo remains unclear. We used multi-photon microscopy to visualize the dynamics and activation of iNKT cells in lymph nodes. Following antigen administration, iNKT cells become confined in a CD1d-dependent manner in close proximity to subcapsular sinus CD169+ macrophages. These macrophages retain, internalize and present lipid antigen, and are required for iNKT cell activation, cytokine production and expansion. Thus, CD169+ macrophages can act as bona fide antigen presenting cells controlling early iNKT cell activation and favouring fast initiation of immune responses. PMID:20228797

  10. CD169(+) macrophages present lipid antigens to mediate early activation of iNKT cells in lymph nodes.

    PubMed

    Barral, Patricia; Polzella, Paolo; Bruckbauer, Andreas; van Rooijen, Nico; Besra, Gurdyal S; Cerundolo, Vincenzo; Batista, Facundo D

    2010-04-01

    Invariant natural killer T cells (iNKT cells) are involved in the host defense against microbial infection. Although it is known that iNKT cells recognize glycolipids presented by CD1d, how and where they encounter antigen in vivo remains unclear. Here we used multiphoton microscopy to visualize the dynamics and activation of iNKT cells in lymph nodes. After antigen administration, iNKT cells became confined in a CD1d-dependent manner in close proximity to subcapsular sinus CD169(+) macrophages. These macrophages retained, internalized and presented lipid antigen and were required for iNKT cell activation, cytokine production and population expansion. Thus, CD169(+) macrophages can act as true antigen-presenting cells controlling early iNKT cell activation and favoring the fast initiation of immune responses.

  11. Perfluorinated chemicals: Differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells

    SciTech Connect

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs – PFOS, PFDoA, PFNA, PFOA – showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA > PFOS ≫ PFNA > PFOA > PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57–80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells. - Highlights: • Eight perfluorinated chemicals of different chain lengths have been selected. • Long chain ones – PFOS, PFDoA, PFNA, PFOA – were cytotoxic in placenta cells. • The uptake of long chain perfluorinated chemicals by cells was comparatively higher. • PFOS, PFOA and the short chain PFBS significantly inhibited aromatase activity. • A mixture of perfluorinated chemicals significantly altered placenta cell

  12. Addition of Ascorbic Acid to the Extracellular Environment Activates Lipoplexes of a Ferrocenyl Lipid and Promotes Cell Transfection

    PubMed Central

    Aytar, Burcu S.; Muller, John P. E.; Golan, Sharon; Hata, Shinichi; Takahashi, Hiro; Kondo, Yukishige; Talmon, Yeshayahu; Abbott, Nicholas L.; Lynn, David M.

    2011-01-01

    The level of cell transfection mediated by lipoplexes formed using the ferrocenyl lipid bis(11-ferrocenylundecyl)dimethylammonium bromide (BFDMA) depends strongly on the oxidation state of the two ferrocenyl groups of the lipid (reduced BFDMA generally mediates high levels of transfection, but oxidized BFDMA mediates very low levels of transfection). Here, we report that it is possible to chemically transform inactive lipoplexes (formed using oxidized BFMDA) to “active” lipoplexes that mediate high levels of transfection by treatment with the small-molecule reducing agent ascorbic acid (vitamin C). Our results demonstrate that this transformation can be conducted in cell culture media and in the presence of cells by addition of ascorbic acid to lipoplex-containing media in which cells are growing. Treatment of lipoplexes of oxidized BFDMA with ascorbic acid resulted in lipoplexes composed of reduced BFDMA, as characterized by UV/vis spectrophotometry, and lead to activated lipoplexes that mediated high levels of transgene expression in the COS-7, HEK 293T/17, HeLa, and NIH 3T3 cell lines. Characterization of internalization of DNA by confocal microscopy and measurements of the zeta potentials of lipoplexes suggested that these large differences in cell transfection result from (i) differences in the extents to which these lipoplexes are internalized by cells and (ii) changes in the oxidation state of BFDMA that occur in the extracellular environment (i.e., prior to internalization of lipoplexes by cells). Characterization of lipoplexes by small-angle neutron scattering (SANS) and by cryogenic transmission electron microscopy (cryo-TEM) revealed changes in the nanostructures of lipoplexes upon the addition of ascorbic acid, from aggregates that were generally amorphous, to aggregates with a more extensive multilamellar nanostructure. The results of this study provide guidance for the design of redox-active lipids that could lead to methods that enable spatial

  13. Local salt substitutes “Obu-otoyo” activate acetylcholinesterase and butyrylcholinesterase and induce lipid peroxidation in rat brain

    PubMed Central

    Oboh, Ganiyu; Ademiluyi, Adedayo O.

    2015-01-01

    Evidence has shown that ingestion of heavy metals can lead to neurodegenerative diseases. This study aimed to investigate the neurotoxic potential of salt substitutes (Obu-Otoyo); salt A (made by burning palm kernel shaft then soaked in water overnight and the extract from the resulting residue is used as the salt substitute) and salt B (an unrefined salt mined from a local site at Ilobu town, Osun-State, Nigeria) by assessing their effect on some key enzymes linked with neurodegenerative disease [acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities] as well as on malondialdehyde (MDA) content of the rat brain. Salt substitutes were fed to normal rats as dietary inclusion at doses of 0.5 and 1.0% for 30 days. Thereafter, the effect of the salt substitutes on AChE and BChE activities as well as on MDA level in the rat brain was determined. The results revealed that the salt substitutes caused a significant (p<0.05) increase in both AChE and BChE activity and also induced lipid peroxidation in the brain of rats in vivo as well as under in vitro condition in a dose-dependent manner. The effect of the salt substitutes on AChE and BChE activities could be attributed to the presence of some toxic heavy metals. Therefore, the ability of the salt substitutes to induce lipid peroxidation and activate AChE and BChE activities could provide some possible mechanism for their neurotoxic effect. PMID:27486373

  14. Local salt substitutes "Obu-otoyo" activate acetylcholinesterase and butyrylcholinesterase and induce lipid peroxidation in rat brain.

    PubMed

    Akinyemi, Ayodele J; Oboh, Ganiyu; Ademiluyi, Adedayo O

    2015-09-01

    Evidence has shown that ingestion of heavy metals can lead to neurodegenerative diseases. This study aimed to investigate the neurotoxic potential of salt substitutes (Obu-Otoyo); salt A (made by burning palm kernel shaft then soaked in water overnight and the extract from the resulting residue is used as the salt substitute) and salt B (an unrefined salt mined from a local site at Ilobu town, Osun-State, Nigeria) by assessing their effect on some key enzymes linked with neurodegenerative disease [acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities] as well as on malondialdehyde (MDA) content of the rat brain. Salt substitutes were fed to normal rats as dietary inclusion at doses of 0.5 and 1.0% for 30 days. Thereafter, the effect of the salt substitutes on AChE and BChE activities as well as on MDA level in the rat brain was determined. The results revealed that the salt substitutes caused a significant (p<0.05) increase in both AChE and BChE activity and also induced lipid peroxidation in the brain of rats in vivo as well as under in vitro condition in a dose-dependent manner. The effect of the salt substitutes on AChE and BChE activities could be attributed to the presence of some toxic heavy metals. Therefore, the ability of the salt substitutes to induce lipid peroxidation and activate AChE and BChE activities could provide some possible mechanism for their neurotoxic effect.

  15. Neutralized nanoparticle composed of SS-cleavable and pH-activated lipid-like material as a long-lasting and liver-specific gene delivery system.

    PubMed

    Ukawa, Masami; Akita, Hidetaka; Hayashi, Yasuhiro; Ishiba, Ryohei; Tange, Kota; Arai, Masaya; Kubo, Kazuhiro; Higuchi, Yuriko; Shimizu, Kazunori; Konishi, Satoshi; Hashida, Mitsuru; Harashima, Hideyoshi

    2014-08-01

    Charge-neutralized lipid envelope-type nanoparticles formed with SS-cleavable and pH-activated lipid-like materials (ssPalm) accumulate rapidly in the liver without forming aggregates in the blood circulation, and result in a liver-specific gene expression for a long duration (>2 weeks) with neither immunological responses nor hepatotoxicity after intraveneous administration, when it carries pDNA free from CpG-motifs.

  16. Docosahexaenoic acid loaded lipid nanoparticles with bactericidal activity against Helicobacter pylori.

    PubMed

    Seabra, Catarina Leal; Nunes, Cláudia; Gomez-Lazaro, Maria; Correia, Marta; Machado, José Carlos; Gonçalves, Inês C; Reis, Celso A; Reis, Salette; Martins, M Cristina L

    2017-03-15

    Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid present in fish oil, has been described as a promising molecule to the treatment of Helicobacter pylori gastric infection. However, due to its highly unsaturated structure, DHA can be easily oxidized loosing part of its bioactivity. This work aims the nanoencapsulation of DHA to improve its bactericidal efficacy against H. pylori. DHA was loaded into nanostructured lipid carriers (NLC) produced by hot homogenization and ultrasonication using a blend of lipids (Precirol ATO5(®), Miglyol-812(®)) and a surfactant (Tween 60(®)). Homogeneous NLC with 302±14nm diameter, -28±3mV surface charge (dynamic and electrophoretic light scattering) and containing 66±7% DHA (UV/VIS spectroscopy) were successfully produced. Bacterial growth curves, performed over 24h in the presence of different DHA concentrations (free or loaded into NLC), demonstrated that nanoencapsulation enhanced DHA bactericidal effect, since DHA-loaded NLC were able to inhibit H. pylori growth in a much lower concentrations (25μM) than free DHA (>100μM). Bioimaging studies, using scanning and transmission electron microscopy and also imaging flow cytometry, demonstrated that DHA-loaded NLC interact with H. pylori membrane, increasing their periplasmic space and disrupting membrane and allowing the leakage of cytoplasmic content. Furthermore, the developed nanoparticles are not cytotoxic to human gastric adenocarcinoma cells at bactericidal concentrations. DHA-loaded NLC should, therefore, be envisaged as an alternative to the current treatments for H. pylori infection.

  17. The impact of membrane lipid composition on macrophage activation in the immune defense against Rhodococcus equi and Pseudomonas aeruginosa.

    PubMed

    Schoeniger, Axel; Adolph, Stephanie; Fuhrmann, Herbert; Schumann, Julia

    2011-01-01

    Nutritional fatty acids are known to have an impact on membrane lipid composition of body cells, including cells of the immune system, thus providing a link between dietary fatty acid uptake, inflammation and immunity. In this study we reveal the significance of macrophage membrane lipid composition on gene expression and cytokine synthesis thereby highlighting signal transduction processes, macrophage activation as well as macrophage defense mechanisms. Using RAW264.7 macrophages as a model system, we identified polyunsaturated fatty acids (PUFA) of both the n-3 and the n-6 family to down-regulate the synthesis of: (i) the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α; (ii) the co-stimulatory molecule CD86; as well as (iii) the antimicrobial polypeptide lysozyme. The action of the fatty acids partially depended on the activation status of the macrophages. It is particularly important to note that the anti-inflammatory action of the PUFA could also be seen in case of infection of RAW264.7 with viable microorganisms of the genera R. equi and P. aeruginosa. In summary, our data provide strong evidence that PUFA from both the n-3 and the n-6 family down-regulate inflammation processes in context of chronic infections caused by persistent pathogens.

  18. Oxidative stress responses and lipid peroxidation damage are induced during dehydration in the production of dry active wine yeasts.

    PubMed

    Garre, Elena; Raginel, Françoise; Palacios, Antonio; Julien, Anne; Matallana, Emilia

    2010-01-01

    The tolerance of the yeast Saccharomyces cerevisiae to desiccation is important for the use of this microorganism in the wine industry, since active dry wine yeast is routinely used as starter for must fermentations. Many studies have shown the complexity of the cellular effects caused by water loss, including oxidative injuries on macromolecular components. However the technological interest of yeast drying was not addressed in those studies, and the dehydration conditions were far from the industrial practice. In the present study a molecular approach was used to characterize the relevant injuring conditions during pilot plant dehydration under two different drying temperatures (i.e., 35 and 41 degrees C). We have analyzed expression changes for several stress gene markers and we have determined two biochemical redox indicators (glutathione and lipid peroxidation levels) during pilot plant dehydration to produce active dry biomass, according to the standard practice in industry. The main gene expression response involves the induction of genes TRR1 and GRX5, corresponding to the two main redox balance systems, thioredoxins and glutathione/glutaredoxins. Elevated glutathione content and significant lipid peroxidation damage indicate the physiological impact of the oxidative stress on cellular components. The comparison between commercial stocks and pilot plant samples demonstrate the suitability of the molecular approach at the pilot plant scale to study physiological traits of industrial yeast products.

  19. Miconazole-loaded solid lipid nanoparticles: formulation and evaluation of a novel formula with high bioavailability and antifungal activity

    PubMed Central

    Aljaeid, Bader Mubarak; Hosny, Khaled Mohamed

    2016-01-01

    Background and objective Miconazole is a broad-spectrum antifungal drug that has poor aqueous solubility (<1 µg/mL); as a result, a reduction in its therapeutic efficacy has been reported. The aim of this study was to formulate and evaluate miconazole-loaded solid lipid nanoparticles (MN-SLNs) for oral administration to find an innovative way to alleviate the disadvantages associated with commercially available capsules. Methods MN-SLNs were prepared by hot homogenization/ultrasonication. The solubility of miconazole in different solid lipids was measured. The effect of process variables, such as surfactant types, homogenization and ultrasonication times, and the charge-inducing agent on the particle size, zeta potential, and encapsulation efficiency were determined. Furthermore, in vitro drug release, antifungal activity against Candida albicans, and in vivo pharmacokinetics were studied in rabbits. Results The MN-SLN, consisting of 1.5% miconazole, 2% Precirol ATO5, 2.5% Cremophor RH40, 0.5% Lecinol, and 0.1% Dicetylphosphate, had an average diameter of 23 nm with a 90.2% entrapment efficiency. Furthermore, the formulation of MN-SLNs enhanced the antifungal activity compared with miconazole capsules. An in vivo pharmacokinetic study revealed that the bioavailability was enhanced by >2.5-fold. Conclusion MN-SLN was more efficient in the treatment of candidiasis with enhanced oral bioavailability and could be a promising carrier for the oral delivery of miconazole. PMID:26869787

  20. Saturated lipids decrease mitofusin 2 leading to endoplasmic reticulum stress activation and insulin resistance in hypothalamic cells.

    PubMed

    Diaz, Brenda; Fuentes-Mera, Lizeth; Tovar, Armando; Montiel, Teresa; Massieu, Lourdes; Martínez-Rodríguez, Herminia Guadalupe; Camacho, Alberto

    2015-11-19

    Endoplasmic reticulum (ER) and mitochondria dysfunction contribute to insulin resistance generation during obesity and diabetes. ER and mitochondria interact through Mitofusin 2 (MTF2), which anchors in the outer mitochondrial and ER membranes regulating energy metabolism. Ablation of MTF2 leads to ER stress activation and insulin resistance. Here we determine whether lipotoxic insult induced by saturated lipids decreases MTF2 expression leading to ER stress response in hypothalamus and its effects on insulin sensitivity using in vitro and in vivo models. We found that lipotoxic stimulation induced by palmitic acid, but not the monounsaturated palmitoleic acid, decreases MTF2 protein levels in hypothalamic mHypoA-CLU192 cells. Also, palmitic acid incubation activates ER stress response evidenced by increase in the protein levels of GRP78/BIP marker at later stage than MTF2 downregulation. Additionally, we found that MTF2 alterations induced by palmitic, but not palmitoleic, stimulation exacerbate insulin resistance in hypothalamic cells. Insulin resistance induced by palmitic acid is prevented by pre-incubation of the anti-inflammatory and the ER stress release reagents, sodium salicylate and 4 phenylbutirate, respectively. Finally, we demonstrated that lipotoxic insult induced by high fat feeding to mice decreases MTF2 proteins levels in arcuate nucleus of hypothalamus. Our data indicate that saturated lipids modulate MTF2 expression in hypothalamus coordinating the ER stress response and the susceptibility to insulin resistance.

  1. Investigation of Channel-Forming Activity of Polyene Macrolide Antibiotics in Planar Lipid Bilayers in the Presence of Dipole Modifiers

    PubMed Central

    Efimova, S. S.; Schagina, L. V.; Ostroumova, O. S.

    2014-01-01

    The role of membrane components, sterols, phospholipids and sphingolipids in the formation and functioning of ion-permeable nanopores formed by antifungal macrolide antibiotics, amphotericin B, nystatin and filipin in planar lipid bilayers was studied. Dipole modifiers, flavonoids and styryl dyes, were used as a tool to study the molecular mechanisms of polyene channel-forming activity. The introduction of dipole modifiers into the membrane bathing solutions was shown to change the conductance of single channels and the steadystate transmembrane current induced by polyene antibiotics in the sterol-containing phospholipid-bilayers. The conductance of single amphotericin B channels was found to depend on the dipole potential of the membrane. The experiments with various phospholipids, sterols, and polyenes led to the assumption that the shape of a phospholipid molecule, the presence of double bonds at the positions 7 and 22 of a sterol molecule, the number of conjugated double bonds, and the presence of an amino sugar in the polyene antibiotic molecule are important factors impacting the stability of polyene-lipid complexes forming ion-permeable pores. Experimental and literature data presented in the paper suggest that the channel-forming activity of polyene antibiotics is also affected by the physicochemical properties of polyene-enriched ordered membrane domains. PMID:25558397

  2. Fatty acids from lipids of marine organisms: molecular biodiversity, roles as biomarkers, biologically active compounds, and economical aspects.

    PubMed

    Bergé, Jean-Pascal; Barnathan, Gilles

    2005-01-01

    Because of their characteristic living environments, marine organisms produce a variety of lipids. Fatty acids constitute the essential part of triglycerides and wax esters, which are the major components of fats and oils. Nevertheless, phospholipids and glycolipids have considerable importance and will be taken into account, especially the latter compounds that excite increasing interest regarding their promising biological activities. Thus, in addition to the major polyunsaturated fatty acids (PUFA) such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, a great number of various fatty acids occur in marine organisms, e.g. saturated, mono- and diunsaturated, branched, halogenated, hydroxylated, methoxylated, non-methylene-interrupted. Various unprecedented chemical structures of fatty acids, and lipid-containing fatty acids, have recently been discovered, especially from the most primitive animals such as sponges and gorgonians. This review of marine lipidology deals with recent advances in the field of fatty acids since the end of the 1990s. Different approaches will be followed, mainly developing biomarkers of trophic chains in marine ecosystems and of chemotaxonomic interest, reporting new structures, especially those with biological activities or biosynthetic interest. An important part of this review will be devoted to the major PUFA, their relevance to health and nutrition, their biosynthesis, their sources (usual and promising) and market.

  3. Epidermal surface lipids.

    PubMed

    Pappas, Apostolos

    2009-03-01

    A layer of lipids, which are of both sebaceous and keratinocyte origin, covers the surface of the skin. The apparent composition of surface lipids varies depending on the selected method of sampling. Lipids produced by the epidermal cells are an insignificant fraction of the total extractable surface lipid on areas rich in sebaceous glands. Due to the holocrine activity of the sebaceous gland, its product of secretion (sebum) is eventually released to the surface of the skin and coats the fur as well. Lipids of epidermal origin fill the spaces between the cells, like mortar or cement. The sebaceous lipids are primarily non polar lipids as triglycerides, wax esters and squalene, while epidermal lipids are a mixture of ceramides, free fatty acids and cholesterol. The composition of the sebaceous lipids is unique and intriguing and elevated sebum excretion is a major factor involved in the pathophysiology of acne. Recent studies have elucidated the roles that epidermal surface lipids have on normal skin functions and acne.

  4. Epidermal surface lipids

    PubMed Central

    2009-01-01

    A layer of lipids, which are of both sebaceous and keratinocyte origin, covers the surface of the skin. The apparent composition of surface lipids varies depending on the selected method of sampling. Lipids produced by the epidermal cells are an insignificant fraction of the total extractable surface lipid on areas rich in sebaceous glands. Due to the holocrine activity of the sebaceous gland, its product of secretion (sebum) is eventually released to the surface of the skin and coats the fur as well. Lipids of epidermal origin fill the spaces between the cells, like mortar or cement. The sebaceous lipids are primarily non polar lipids as triglycerides, wax esters and squalene, while epidermal lipids are a mixture of ceramides, free fatty acids and cholesterol. The composition of the sebaceous lipids is unique and intriguing and elevated sebum excretion is a major factor involved in the pathophysiology of acne. Recent studies have elucidated the roles that epidermal surface lipids have on normal skin functions and acne. PMID:20224687

  5. Benefits of Omega-3 Fatty Acids Supplementation on Serum Paraoxonase 1 Activity and Lipids Ratios in Polycystic Ovary Syndrome

    PubMed Central

    Mohammadi, Elahe; Rafraf, Maryam

    2012-01-01

    Background: Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with increased risk of cardiovascular disease. The purpose of this study was to investigate the ef¬fects of omega-3 fatty acids on serum paraoxonase 1 activity and lipids ratios in polycystic ovary syndrome. Methods: This double-blind randomized controlled clinical trial was conducted on 64 PCOS pa¬tients with 20-35 years old. Thirty two of the subjects had taken 4 g/day omega -3 fatty acids and 32 patients were given placebo for 8 weeks. Fasting blood samples, anthropometric measure¬ments and dietary intakes were collected at the beginning and the end of the study. Serum total cholesterol, triglyceride, and HDL-C were measured using the enzymatic methods. LDL-C con¬centration was calculated by the Friedewald formula and arylesterase activity of serum PON1 was measured. Data were analyzed using SPSS software. Results: Omega-3 fatty acids significantly decreased TC/HDL-C and LDL-C/HDL-C ratios (P = 0.009 for both) and significantly increased serum PON1 activity (P = 0.048) compared with placebo. Changes in TG/HDL-C ratio were not statistically significant in omega-3 fatty acids group at the end of the study in comparison to placebo group. Reduction in TC/HDL-C, LDL-C/HDL-C and TG/HDL-C ratios and increase in serum PON1 activity were also significant in omega-3 fatty acids group at the end of the study compared with baseline values (P <0.001, P < 0.001, P = 0.004, and P = 0.001, respectively). Conclusion: Omega-3 fatty acids may decrease the risk for cardiovascular disease through the improvement in paraxonase-1 activity and reduction in some lipids ratio in PCOS women. PMID:24688934

  6. Lipid Requirements for the Enzymatic Activity of MraY Translocases and in Vitro Reconstitution of the Lipid II Synthesis Pathway.

    PubMed

    Henrich, Erik; Ma, Yi; Engels, Ina; Münch, Daniela; Otten, Christian; Schneider, Tanja; Henrichfreise, Beate; Sahl, Hans-Georg; Dötsch, Volker; Bernhard, Frank

    2016-01-29

    Screening of new compounds directed against key protein targets must continually keep pace with emerging antibiotic resistances. Although periplasmic enzymes of bacterial cell wall biosynthesis have been among the first drug targets, compounds directed against the membrane-integrated catalysts are hardly available. A promising future target is the integral membrane protein MraY catalyzing the first membrane associated step within the cytoplasmic pathway of bacterial peptidoglycan biosynthesis. However, the expression of most MraY homologues in cellular expression systems is challenging and limits biochemical analysis. We report the efficient production of MraY homologues from various human pathogens by synthetic cell-free expression approaches and their subsequent characterization. MraY homologues originating from Bordetella pertussis, Helicobacter pylori, Chlamydia pneumoniae, Borrelia burgdorferi, and Escherichia coli as well as Bacillus subtilis were co-translationally solubilized using either detergent micelles or preformed nanodiscs assembled with defined membranes. All MraY enzymes originating from Gram-negative bacteria were sensitive to detergents and required nanodiscs containing negatively charged lipids for obtaining a stable and functionally folded conformation. In contrast, the Gram-positive B. subtilis MraY not only tolerates detergent but is also less specific for its lipid environment. The MraY·nanodisc complexes were able to reconstitute a complete in vitro lipid I and lipid II forming pipeline in combination with the cell-free expressed soluble enzymes MurA-F and with the membrane-associated protein MurG. As a proof of principle for future screening platforms, we demonstrate the inhibition of the in vitro lipid II biosynthesis with the specific inhibitors fosfomycin, feglymycin, and tunicamycin.

  7. Differences in lipid distribution and expression of peroxisome proliferator-activated receptor gamma and lipoprotein lipase genes in torafugu and red seabream.

    PubMed

    Kaneko, Gen; Yamada, Toshihiro; Han, Yuna; Hirano, Yuki; Khieokhajonkhet, Anurak; Shirakami, Hirohito; Nagasaka, Reiko; Kondo, Hidehiro; Hirono, Ikuo; Ushio, Hideki; Watabe, Shugo

    2013-04-01

    Lipid content is one of the major determinants of the meat quality in fish. However, the mechanisms underlying the species-specific distribution of lipid are still poorly understood. The present study was undertaken to investigate the mechanisms associated with lipid accumulation in two species of fish: torafugu (a puffer fish) and red seabream. The lipid content of liver and carcass were 67.0% and 0.8% for torafugu, respectively, and 8.8% and 7.3% for red seabream, respectively. Visceral adipose tissue was only apparent in the red seabream and accounted for 73.3% of its total lipid content. Oil red O staining confirmed this species-specific lipid distribution, and further demonstrated that the lipid in the skeletal muscle of the red seabream was mainly localized in the myosepta. We subsequently cloned cDNAs from torafugu encoding lipoprotein lipase 1 (LPL1) and LPL2, important enzymes for the uptake of lipids from blood circulation system into various tissues. The relative mRNA levels of peroxisome proliferator-activated receptor gamma (PPARγ) and the LPLs of torafugu were determined by quantitative real-time PCR together with their counterparts in red seabream previously reported. The relative mRNA levels of PPARγ and LPL1 correlated closely to the lipid distribution of both fish, being significantly higher in liver than skeletal muscle in torafugu, whereas the highest in the adipose tissue, followed by liver and skeletal muscle in red seabream. However, the relative mRNA levels of LPL2 were tenfold lower than LPL1 in both species and only correlated to lipid distribution in torafugu, suggesting that LPL2 has only a minor role in lipid accumulation. In situ hybridization revealed that the transcripts of LPL1 co-localized with lipids in the adipocytes located along the myosepta of the skeletal muscle of red seabream. These results suggest that the transcriptional regulation of PPARγ and LPL1 is responsible for the species-specific lipid distribution of torafugu

  8. Exoplasmic cysteine Cys384 of the HDL receptor SR-BI is critical for its sensitivity to a small-molecule inhibitor and normal lipid transport activity

    PubMed Central

    Yu, Miao; Romer, Katherine A.; Nieland, Thomas J. F.; Xu, Shangzhe; Saenz-Vash, Veronica; Penman, Marsha; Yesilaltay, Ayce; Carr, Steven A.; Krieger, Monty

    2011-01-01

    The HDL receptor, scavenger receptor, class B, type I (SR-BI), is a homooligomeric cell surface glycoprotein that controls HDL structure and metabolism by mediating the cellular selective uptake of lipids, mainly cholesteryl esters, from HDL. The mechanism underlying SR-BI-mediated lipid transfer, which differs from classic receptor-mediated endocytosis, involves a two-step process (binding followed by lipid transport) that is poorly understood. Our previous structure/activity analysis of the small-molecule inhibitor blocker of lipid transport 1 (BLT-1), which potently (IC50 ∼ 50 nM) blocks SR-BI-mediated lipid transport, established that the sulfur in BLT-1’s thiosemicarbazone moiety was essential for activity. Here we show that BLT-1 is an irreversible inhibitor of SR-BI, raising the possibility that cysteine(s) in SR-BI interact with BLT-1. Mass spectrometric analysis of purified SR-BI showed two of its six exoplasmic cysteines have free thiol groups (Cys251 and Cys384). Converting Cys384 (but not Cys251) to serine resulted in complete BLT-1 insensitivity, establishing that the unique molecular target of BLT-1 inhibition of cellular SR-BI dependent lipid transport is SR-BI itself. The C384S substitution reduced the receptor’s intrinsic lipid uptake activity by approximately 60% without dramatically altering its surface expression, homooligomerization, or HDL binding. Thus, a small-molecule screening approach identified a key residue in SR-BI involved in lipid transport, providing a powerful springboard into the analyses of the structure and mechanism of SR-BI, and highlighting the power of this approach for such analyses. PMID:21746906

  9. Lipids: Absorption and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipid has long been recognized as an important dietary component. Dietary lipid (fat) is a critical source of metabolic energy and a substrate for the synthesis of metabolically active compounds (essential fatty acids), and serves as a carrier for other nutrients such as the fat-soluble vitamins A, ...

  10. Perfluorinated chemicals: differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells.

    PubMed

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs--PFOS, PFDoA, PFNA, PFOA--showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA>PFOS≫PFNA>PFOA>PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57-80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells.

  11. Lipid-lowering activity of Cow urine ark in guinea pigs fed with a high cholesterol diet

    PubMed Central

    Manubhai, Chawda Hiren; Rasiklal, Mandavia Divyesh; Natvarlal, Baxi Seema; Kishorbhai, Vadgama Vishalkumar; Rajkishor, Tripathi ‎Chandrabhanu

    2014-01-01

    Objectives: Cow urine ark (CUA), known as “Amrita” as mentioned in Ayurveda, contains‎ anti-hyperglycemic and antioxidant effects. Therefore, we designed the present study to evaluate the lipid ‎lowering activity of CUA and its possible implication in metabolic syndrome.‎ Materials and Methods: Thirty guinea pigs of either sex were divided into five groups: Group 1 and 2 serving as a vehicle ‎and sham control, received normal and high fat diet for 60 days respectively; Group 3, 4 and 5 ‎received high fat diet for 60 days with CUA 0.8 ml/kg, 1.6 ml/kg and rosuvastatin (1.5 mg/kg) on the‎last 30 days of study period, respectively. Serum lipid profile (total cholesterol, triglycerides, LDL-‎C, VLDL-C, HDL-C, total Cholesterol/HDL-C) and serum enzymes (ALT, AST, ALP, LDH and CK-MB) ‎were performed in each group at the beginning and end of the study. Histological study of liver and ‎kidney was done in each group. Results: CUA (0.8 ml/kg) significantly decreased the serum triglycerides and VLDL-C, but CUA (1.6 ml/kg) ‎decreased the total serum Cholesterol, triglycerides and VLDL-C (p < 0.05). Higher dose (1.6 ml/kg) of ‎CUA also increased HDL-C level, significantly (p < 0.05). CUA reduced serum AST, ALP and LDH ‎level, which was statistically significant as well, while it also decreased the accumulation of lipid in hepatocytes as ‎compared to sham control.‎ Conclusions: CUA reduced triglycerides, increased HDL-C and found to be hepatoprotective in ‎animals that are on a high fat diet. PMID:25386398

  12. Using fluorine nuclear magnetic resonance to probe the interaction of membrane-active peptides with the lipid bilayer.

    PubMed

    Buer, Benjamin C; Chugh, Jeetender; Al-Hashimi, Hashim M; Marsh, E Neil G

    2010-07-13

    A variety of biologically active peptides exert their function through direct interactions with the lipid membrane of the cell. These surface interactions are generally transient and highly dynamic, making them hard to study. Here we have examined the feasibility of using solution phase (19)F nuclear magnetic resonance (NMR) to study peptide-membrane interactions. Using the antimicrobial peptide MSI-78 as a model system, we demonstrate that peptide binding to either small unilamellar vesicles (SUVs) or bicelles can readily be detected by simple one-dimensional (19)F NMR experiments with peptides labeled with l-4,4,4-trifluoroethylglycine. The (19)F chemical shift associated with the peptide-membrane complex is sensitive both to the position of the trifluoromethyl reporter group (whether in the hydrophobic face or positively charged face of the amphipathic peptide) and to the curvature of the lipid bilayer (whether the peptide is bound to SUVs or bicelles). (19)F spin echo experiments using the Carr-Purcell-Meiboom-Gill pulse sequence were used to measure the transverse relaxation (T(2)) of the nucleus and thereby examine the local mobility of the MSI-78 analogues bound to bicelles. The fluorine probe positioned in the hydrophobic face of the peptide relaxes at a rate that correlates with the tumbling of the bicelle, suggesting that it is relatively immobile, whereas the probe at the positively charged face relaxes more slowly, indicating this position is much more dynamic. These results are in accord with structural models of MSI-78 bound to lipids and point to the feasibility of using fluorine-labeled peptides to monitor peptide-membrane interactions in living cells.

  13. Beyond lipids, pharmacological PPARalpha activation has important effects on amino acid metabolism as studied in the rat.

    PubMed

    Sheikh, Kashif; Camejo, Germán; Lanne, Boel; Halvarsson, Torbjörn; Landergren, Marie Rydén; Oakes, Nicholas D

    2007-04-01

    PPARalpha agonists have been characterized largely in terms of their effects on lipids and glucose metabolism, whereas little has been reported about effects on amino acid metabolism. We studied responses to the PPARalpha agonist WY 14,643 (30 micromol x kg(-1) x day(-1) for 4 wk) in rats fed a saturated fat diet. Plasma and urine were analyzed with proton NMR. Plasma amino acids were measured using HPLC, and hepatic gene expression was assessed with DNA arrays. The high-fat diet elevated plasma levels of insulin and triglycerides (TG), and WY 14,643 treatment ameliorated this insulin resistance and dyslipidemia, lowering plasma insulin and TG levels. In addition, treatment decreased body weight gain, without altering cumulative food intake, and increased liver mass. WY 14,643 increased plasma levels of 12 of 22 amino acids, including glucogenic and some ketogenic amino acids, whereas arginine was significantly decreased. There was no alteration in branched-chain amino acid levels. Compared with the fat-fed control animals, WY 14,643-treated animals had raised plasma urea and ammonia levels as well as raised urine levels of N-methylnicotinamide and dimethylglycine. WY 14,643 induced changes in a number of key genes involved in amino acid metabolism in addition to expected effects on hepatic genes involved in lipid catabolism and ketone body formation. In conclusion, the present results suggest that, in rodents, effects of pharmacological PPARalpha activation extend beyond control of lipid metabolism to include important effects on whole body amino acid mobilization and hepatic amino acid metabolism.

  14. Physical properties, lipid composition and enzyme activities of hepatic subcellular membranes from chick embryo after ethanol treatment

    SciTech Connect

    Sanchez-Amate, M.C.; Marco, C.; Segovia, J.L. )

    1992-01-01

    Exposure of chick embryos to ethanol resulted in significant alterations to the lipid composition of various different hepatic subcellular membranes. A marked decrease in cholesterol levels and an increase in the phospholipid content of microsomes and mitochondria was observed. Ethanol also affected the fatty acid profiles, mainly by decreasing the percentage of oleic acid in phosphatidylcholine and phosphatidylethanolamine in the mitochondria and phosphatidylethanolamine in the microsomes. In spite of these changes ethanol only induced alterations in the fluidity of the mitochondrial membranes, which showed a more rigid core, in contrast to the phospholipid-head region, which was not affected. In accordance with the changes observed in the physical state of the membrane, the enzymes involved in the microsomal electron-transport systems were not modified by ethanol, while cytochrome oxidase activity decreased by 50% compared to the activity in the mitochondria from control chick embryos.

  15. Effect of Hypoxia on the Calcium and Magnesium Content, Lipid Peroxidation Level, and Ca2+-ATPase Activity of Syncytiotrophoblast Plasma Membranes from Placental Explants

    PubMed Central

    Chiarello, Delia I.; Benzo, Zully; Piñero, Sandy; Botana, Desirée; Abad, Cilia

    2014-01-01

    In the current study the possible relationship between the Ca2+/Mg2+ ratio of human syncytiotrophoblast plasma membranes and their lipid peroxidation and Ca2+-ATPase activity was determined. Syncytiotrophoblast plasma membranes of placental explants cultured under hypoxia increased their lipid peroxidation and Ca2+ content, diminished their Ca2+-ATPase activity, and kept their Mg2+ content unchanged. Membranes preincubated with different concentrations of Ca2+ increased their Ca2+ content without changes in their Mg2+ content. There is a direct relationship between Ca2+ content and lipid peroxidation of the membranes, as well as an inverse relationship between their Ca2+ content and Ca2+-ATPase activity. On the contrary, preincubation of membranes with different concentrations of Mg2+ showed a higher Mg2+ content without changing their lipid peroxidation and Ca2+-ATPase activity. Explants cultured under hypoxia in the presence of 4 mM MgSO4 showed similar values of lipid peroxidation and Ca2+-ATPase activity of their membranes compared to those of explants cultured under normoxia. Increased Ca2+ content of the membranes by interacting with negatively charged phospholipids could result in destabilizing effects of the membrane structure, exposing hydrocarbon chains of fatty acids to the action of free radicals. Mg2+ might exert a stabilizing effect of the membranes, avoiding their exposure to free radicals. PMID:25180187

  16. Peroxisome Proliferator-activated Receptor γ Regulates Genes Involved in Insulin/Insulin-like Growth Factor Signaling and Lipid Metabolism during Adipogenesis through Functionally Distinct Enhancer Classes*

    PubMed Central

    Oger, Frédérik; Dubois-Chevalier, Julie; Gheeraert, Céline; Avner, Stéphane; Durand, Emmanuelle; Froguel, Philippe; Salbert, Gilles; Staels, Bart; Lefebvre, Philippe; Eeckhoute, Jérôme

    2014-01-01

    The nuclear receptor peroxisome proliferator-activated receptor (PPAR) γ is a transcription factor whose expression is induced during adipogenesis and that is required for the acquisition and control of mature adipocyte functions. Indeed, PPARγ induces the expression of genes involved in lipid synthesis and storage through enhancers activated during adipocyte differentiation. Here, we show that PPARγ also binds to enhancers already active in preadipocytes as evidenced by an active chromatin state including lower DNA methylation levels despite higher CpG content. These constitutive enhancers are linked to genes involved in the insulin/insulin-like growth factor signaling pathway that are transcriptionally induced during adipogenesis but to a lower extent than lipid metabolism genes, because of stronger basal expression levels in preadipocytes. This is consistent with the sequential involvement of hormonal sensitivity and lipid handling during adipocyte maturation and correlates with the chromatin structure dynamics at constitutive and activated enhancers. Interestingly, constitutive enhancers are evolutionary conserved and can be activated in other tissues, in contrast to enhancers controlling lipid handling genes whose activation is more restricted to adipocytes. Thus, PPARγ utilizes both broadly active and cell type-specific enhancers to modulate the dynamic range of activation of genes involved in the adipogenic process. PMID:24288131

  17. Lipid peroxidation-derived aldehyde-protein adducts contribute to trichloroethene-mediated autoimmunity via activation of CD4+ T cells.

    PubMed

    Wang, Gangduo; König, Rolf; Ansari, G A S; Khan, M Firoze

    2008-04-01

    Lipid peroxidation is implicated in the pathogenesis of various autoimmune diseases. Lipid peroxidation-derived aldehydes such as malondialdehyde (MDA) and 4-hydroxynonenal (HNE) are highly reactive and bind to proteins, but their role in eliciting an autoimmune response and their contribution to disease pathogenesis remain unclear. To investigate the role of lipid peroxidation in the induction and/or exacerbation of autoimmune response, 6-week-old autoimmune-prone female MRL+/+ mice were treated for 4 weeks with trichloroethene (TCE; 10 mmol/kg, ip, once a week), an environmental contaminant known to induce lipid peroxidation. Sera from TCE-treated mice showed significant levels of antibodies against MDA-and HNE-adducted proteins along with antinuclear antibodies. This suggested that TCE exposure not only caused increased lipid peroxidation, but also accelerated autoimmune responses. Furthermore, stimulation of cultured splenic lymphocytes from both control and TCE-treated mice with MDA-adducted mouse serum albumin (MDA-MSA) or HNE-MSA for 72 h showed significant proliferation of CD4+ T cells in TCE-treated mice as analyzed by flow cytometry. Also, splenic lymphocytes from TCE-treated mice released more IL-2 and IFN-gamma into cultures when stimulated with MDA-MSA or HNE-MSA, suggesting a Th1 cell activation. Thus, our data suggest a role for lipid peroxidation-derived aldehydes in TCE-mediated autoimmune responses and involvement of Th1 cell activation.

  18. Study of supported bilayer lipid membranes for use in chemo-electric energy conversion via active proton transport

    NASA Astrophysics Data System (ADS)

    Sarles, Stephen A.; Sundaresan, Vishnu B.; Leo, Donald J.

    2007-09-01

    Bilayer lipid membranes (BLMs) have been studied extensively due to functional and structural similarities to cell membranes, fostering research to understand ion-channel protein functions, measure bilayer mechanical properties, and identify self-assembly mechanisms. BLMs have traditionally been formed across single pores in substrates such as PTFE (Teflon). The incorporation of ion-channel proteins into the lipid bilayer enables the selective transfer of ions and fluid through the BLM. Processes of this nature have led to the measurement of ion current flowing across the lipid membrane and have been used to develop sensors that signal the presence of a particular reactant (glucose, urea, penicillin), improve drug recognition in cells, and develop materials capable of creating chemical energy from light. Recent research at Virginia Tech has shown that the incorporation of proton transporters in a supported BLM formed across an array of pores can convert chemical energy available in the adenosine triphosphate (ATP) into electricity. Experimental results from this work show that the system-named Biocell-is capable of developing 2µW/cm2 of membrane area with 15μl of ATPase. Efforts to increase the power output and conversion efficiency of this process while moving toward a packaged device present a unique engineering problem. The bilayer, as host to the active proton transporters, must therefore be formed evenly across a porous substrate, remain stable and yet fluid-like for protein interaction, and exhibit a large seal resistance. This article presents the ongoing work to characterize the Biocell using impedance analysis. Electrical impedance spectroscopy (EIS) is used to study the effect of adding ATPase proteins to POPS:POPE bilayer lipid membranes and correlate structural changes evident in the impedance data to the energy-conversion capability of various partial and whole Biocell assemblies. The specific membrane resistance of a pure BLM drops from 40-120k

  19. Relation of fatty acid composition in lead-exposed mallards to fat mobilization, lipid peroxidation and alkaline phosphatase activity

    USGS Publications Warehouse

    Mateo, R.; Beyer, W.N.; Spann, J.W.; Hoffman, D.J.

    2003-01-01

    The increase of n-6 polyunsaturated fatty acids (PUFA) in animal tissues has been proposed as a mechanism of Pb poisoning through lipid peroxidation or altered eicosanoids metabolism. We have studied fatty acid (FA) composition in liver and brain of mallards (Anas platyrhynchos) feeding for three weeks on diets containing combinations of low or high levels of vitamin E (20 or 200 UI/kg) and Pb (0 or 2 g/kg). Saturated FA, n-6 PUFA and total concentrations of FA were higher in livers of Pb-exposed mallards, but not in their brains. The percentage of n-6 PUFA in liver and brain was slightly higher in Pb-exposed mallards. The increase of n-6 PUFA in liver was associated with increased triglycerides and cholesterol in plasma, thus could be in part attributed to feed refusal and fat mobilization. The hepatic ratios between adrenic acid (22:4 n-6) and arachidonic acid (20:4 n-6) or between adrenic acid and linoleic acid (18:2 n-6) were higher in Pb exposed birds, supporting the existing hypothesis of increased fatty acid elongation by Pb. Among the possible consequences of increased n-6 PUFA concentration in tissues, we found increased lipid peroxidation in liver without important histopathological changes, and decreased plasma alkaline phosphatase activity that may reflect altered bone metabolism in birds.

  20. Channel-forming activity of syringopeptin 25A in mercury-supported lipid bilayers with a phosphatidylcholine distal leaflet.

    PubMed

    Becucci, Lucia; Rossi, Marta; Fiore, Alberto; Scaloni, Andrea; Guidelli, Rolando

    2016-04-01

    The channel-forming activity of the lipodepsipeptide syringopeptin 25A (SP25A) was investigated at a tethered bilayer lipid membrane (tBLM) with a dioleoylphosphatidylcholine distal leaflet, anchored to a mercury electrode through a hydrophilic tetraethyleneoxy spacer. SP25A was incorporated in the tBLM from different aqueous solutions by recording a series of impedance spectra over a potential range encompassing non-physiological transmembrane potential (Δϕ) values. Once incorporated, SP25A forms stable ion channels over the narrower range of physiological Δϕ values. Ion flow into and out of the spacer, through the lipid bilayer moiety of the tBLM, was monitored by potential step chronocoulometry and cyclic voltammetry at pH3, 5.4 and 6.8. Potassium ion flow into the hydrophilic spacer along the SP25A channels, during the negative potential scan, proceeds in two stages, except at the higher pH and lower SP25A concentration adopted, where it proceeds in a single stage. In light of the behavior of SP25A single channel currents reported in the literature, the first stage is ascribed to large channels resulting from the aggregation of small ones, while the second more negative stage is associated with the small channels resulting from the disaggregation of the large ones.

  1. Functional nanoemulsion-hybrid lipid nanocarriers enhance the bioavailability and anti-cancer activity of lipophilic diferuloylmethane

    NASA Astrophysics Data System (ADS)

    Sun, Lili; Wan, Kun; Hu, Xueyuan; Zhang, Yonghong; Yan, Zijun; Feng, Jiao; Zhang, Jingqing

    2016-02-01

    The purpose of this study was to assess the enhanced physicochemical characteristics, in vitro release behavior, anti-lung cancer activity, gastrointestinal absorption, in vivo bioavailability and bioequivalence of functional nanoemulsion-hybrid lipid nanocarriers containing diferuloylmethane (DNHLNs). The DNHLNs were first fabricated by loading water-in-oil nanoemulsions into hybrid lipid nanosystems using nanoemulsion-thin film-sonication dispersion technologies. The in situ absorption and in vitro and in vivo kinetic features of DNHLNs were measured using an in situ unidirectional perfusion method, a dynamic dialysis method and a plasma concentration-time profile-based method, respectively. The cytotoxic effects of DNHLNs in lung adenocarcinoma A549 cells were examined using MTT colorimetric analysis. The absorptive constants and permeabilities of DNHLNs in four gastrointestinal sections increased by 1.43-3.23 times and by 3.10-7.76 times that of diferuloylmethane (DIF), respectively. The relative bioavailability of DNHLNs to free DIF was 855.02%. DNHLNs inhibited cancer cell growth in a time- and dose-dependent manner. DNHLNs markedly improved the absorption and bioavailability of DIF after oral administration. DNHLNs had stronger inhibitory effects on the viability of A549 cells than that of free DIF. DNHLNs might be potentially promising nanocarriers for DIF delivery via the oral route to address unmet clinical needs.

  2. Disruption of lipid homeostasis in the Gram-negative cell envelope activates a novel cell death pathway.

    PubMed

    Sutterlin, Holly A; Shi, Handuo; May, Kerrie L; Miguel, Amanda; Khare, Somya; Huang, Kerwyn Casey; Silhavy, Thomas J

    2016-03-15

    Gram-negative bacteria balance synthesis of the outer membrane (OM), cell wall, and cytoplasmic contents during growth via unknown mechanisms. Here, we show that a dominant mutation (designated mlaA*, maintenance of lipid asymmetry) that alters MlaA, a lipoprotein that removes phospholipids from the outer leaflet of the OM of Escherichia coli, increases OM permeability, lipopolysaccharide levels, drug sensitivity, and cell death in stationary phase. Surprisingly, single-cell imaging revealed that death occurs after protracted loss of OM material through vesiculation and blebbing at cell-division sites and compensatory shrinkage of the inner membrane, eventually resulting in rupture and slow leakage of cytoplasmic contents. The death of mlaA* cells was linked to fatty acid depletion and was not affected by membrane depolarization, suggesting that lipids flow from the inner membrane to the OM in an energy-independent manner. Suppressor analysis suggested that the dominant mlaA* mutation activates phospholipase A, resulting in increased levels of lipopolysaccharide and OM vesiculation that ultimately undermine the integrity of the cell envelope by depleting the inner membrane of phospholipids. This novel cell-death pathway suggests that balanced synthesis across both membranes is key to the mechanical integrity of the Gram-negative cell envelope.

  3. Myricetin Increases Hepatic Peroxisome Proliferator-Activated Receptor α Protein Expression and Decreases Plasma Lipids and Adiposity in Rats

    PubMed Central

    Chang, Chia Ju; Tzeng, Thing-Fong; Liou, Shorong-Shii; Chang, Yuan-Shiun; Liu, I-Min

    2012-01-01

    The aim of this study was to investigate the antiobesity and antihyperlipidaemic effects of myricetin. Myricetin exhibited a significant concentration-dependent decrease in the intracellular accumulation of triglyceride in 3T3-L1 adipocytes. The high-fat diet (HFD)-fed rats were dosed orally with myricetin or fenofibrate, once daily for eight weeks. Myricetin (300 mg kg−1 per day) displayed similar characteristics to fenofibrate (100 mg kg−1 per day) in reducing lowered body weight (BW) gain, visceral fat-pad weights and plasma lipid levels of HFD-fed rats. Myricetin also reduced the hepatic triglyceride and cholesterol contents, as well as lowered hepatic lipid droplets accumulation and epididymal adipocyte size in HFD-fed rats. Myricetin and fenofibrate reversed the HFD-induced down-regulation of the hepatic peroxisome proliferator activated receptor (PPAR)α. HFD-induced decreases of the hepatic protein level of acyl-CoA oxidase and cytochrome P450 isoform 4A1 were up-regulated by myricetin and fenofibrate. The elevated expressions of hepatic sterol regulatory element binding proteins (SREBPs) of HFD-fed rats were lowered by myricetin and fenofibrate. These results suggest that myricetin suppressed BW gain and body fat accumulation by increasing the fatty acid oxidation, which was likely mediated via up-regulation of PPARα and down-regulation of SREBP expressions in the liver of HFD-fed rats. PMID:22474525

  4. Disruption of lipid homeostasis in the Gram-negative cell envelope activates a novel cell death pathway

    PubMed Central

    Sutterlin, Holly A.; Shi, Handuo; May, Kerrie L.; Miguel, Amanda; Khare, Somya; Huang, Kerwyn Casey; Silhavy, Thomas J.

    2016-01-01

    Gram-negative bacteria balance synthesis of the outer membrane (OM), cell wall, and cytoplasmic contents during growth via unknown mechanisms. Here, we show that a dominant mutation (designated mlaA*, maintenance of lipid asymmetry) that alters MlaA, a lipoprotein that removes phospholipids from the outer leaflet of the OM of Escherichia coli, increases OM permeability, lipopolysaccharide levels, drug sensitivity, and cell death in stationary phase. Surprisingly, single-cell imaging revealed that death occurs after protracted loss of OM material through vesiculation and blebbing at cell-division sites and compensatory shrinkage of the inner membrane, eventually resulting in rupture and slow leakage of cytoplasmic contents. The death of mlaA* cells was linked to fatty acid depletion and was not affected by membrane depolarization, suggesting that lipids flow from the inner membrane to the OM in an energy-independent manner. Suppressor analysis suggested that the dominant mlaA* mutation activates phospholipase A, resulting in increased levels of lipopolysaccharide and OM vesiculation that ultimately undermine the integrity of the cell envelope by depleting the inner membrane of phospholipids. This novel cell-death pathway suggests that balanced synthesis across both membranes is key to the mechanical integrity of the Gram-negative cell envelope. PMID:26929379

  5. Antimicrobial activities of novel mannosyl lipids isolated from the biocontrol fungus Simplicillium lamellicola BCP against phytopathogenic bacteria.

    PubMed

    Le Dang, Quang; Shin, Teak Soo; Park, Myung Soo; Choi, Yong Ho; Choi, Gyung Ja; Jang, Kyoung Soo; Kim, In Seon; Kim, Jin-Cheol

    2014-04-16

    The antagonistic fungus Simplicillium lamellicola BCP has been developed as a microbial biopesticide that effectively controls the development of various plant diseases caused by both pathogenic bacteria and pathogenic fungi. Antibacterial bioassay-directed fractionation was used to isolate mannosyl lipids from S. lamellicola BCP, and the structures of these compounds were elucidated using spectral analysis and chemical degradation. Three novel mannosyl lipids were characterized and identified as halymecins F and G and (3R,5R)-3-O-β-D-mannosyl-3,5-dihydrodecanoic acid. Massoia lactone and (3R, 5R)-3-hydroxydecan-5-olide were also isolated from S. lamellicola BCP. The three novel compounds inhibited the growth of the majority of phytopathogenic bacteria that were tested, and halymecin F displayed the strongest antibacterial activity. Agrobacterium tumefaciens was the most sensitive to the three novel compounds, with IC₅₀ values ranging from 1.58 to 24.8 μg/mL. The ethyl acetate extract of the fermentation broth from the antagonistic fungus effectively reduced the bacterial wilt caused by Ralstonia solanacearum on tomato seedlings. These results indicate that S. lamellicola BCP suppresses the development of plant bacterial diseases through the production of antibacterial metabolites.

  6. Effects of hydrostatic pressure on lipid bilayer membranes. I. Influence on membrane thickness and activation volumes of lipophilic ion transport.

    PubMed Central

    Benz, R; Conti, F

    1986-01-01

    Measurements of membrane capacitance, Cm, were performed on lipid bilayers of different lipidic composition (diphytanoyl phosphatidylcholine PPhPC, dioleoyl phosphatidylcholine DOPE, glycerylmonooleate GMO) and containing n-decane as solvent. In the same membranes, the absorption of the lipophilic ions dipicrylamine (DPA-) and tetraphenylborate (TPhB-), and the kinetics of their translocation between the two membrane faces have been studied. The data were obtained from charge pulse relaxation measurements. Upon increasing pressure the specific capacity Cm increased in a fully reversible and reproducible way reflecting a thinning of the membrane that is attributed to extrusion of n-decane from the black membrane area. High pressure decreased the rate constant, ki, for lipophilic ion translocation. After correcting for changes in the height of the energy barrier for translocation due to membrane thinning the pressure dependence of ki yields an apparent activation volume for translocation of approximately 14 cm3/mol both for DPA- and TPhB-. Changes in lipophilic ion absorption following a step of pressure developed with a rather slow time course due to diffusion limitations in solution. The stationary concentration of membrane absorbed lipophilic ions increased with pressure according to an apparent volume of absorption of about -10 cm3/mol. The relevance of the results for the interpretation of the effects of pressure on nerve membrane physiology is discussed. Images FIGURE 1 PMID:3730509

  7. Membrane Morphology Is Actively Transformed by Covalent Binding of the Protein Atg8 to PE-Lipids

    PubMed Central

    Knorr, Roland L.; Nakatogawa, Hitoshi; Ohsumi, Yoshinori; Lipowsky, Reinhard; Baumgart, Tobias; Dimova, Rumiana

    2014-01-01

    Autophagy is a cellular degradation pathway involving the shape transformation of lipid bilayers. During the onset of autophagy, the water-soluble protein Atg8 binds covalently to phosphatdylethanolamines (PEs) in the membrane in an ubiquitin-like reaction coupled to ATP hydrolysis. We reconstituted the Atg8 conjugation system in giant and nm-sized vesicles with a minimal set of enzymes and observed that formation of Atg8-PE on giant vesicles can cause substantial tubulation of membranes even in the absence of Atg12-Atg5-Atg16. Our findings show that ubiquitin-like processes can actively change properties of lipid membranes and that membrane crowding by proteins can be dynamically regulated in cells. Furthermore we provide evidence for curvature sorting of Atg8-PE. Curvature generation and sorting are directly linked to organelle shapes and, thus, to biological function. Our results suggest that a positive feedback exists between the ubiquitin-like reaction and the membrane curvature, which is important for dynamic shape changes of cell membranes, such as those involved in the formation of autophagosomes. PMID:25522362

  8. Toward the de novo design of antimicrobial peptides: Lack of correlation between peptide permeabilization of lipid vesicles and antimicrobial, cytolytic, or cytotoxic activity in living cells.

    PubMed

    He, Jing; Krauson, Aram J; Wimley, William C

    2014-01-01

    We previously performed a lipid vesicle-based, high-throughput screen on a 26-residue combinatorial peptide library that was designed de novo to yield membrane-permeabilizing peptides that fold into β-sheets. The most active and soluble library members that were identified permeabilized lipid vesicles detectably, but not with high potency. Nonetheless, they were broad-spectrum, membrane-permeabilizing antibiotics with minimum sterilizing activity at low µM concentrations. In an expansion of that work, we recently performed an iterative screen in which an active consensus sequence from that first-generation library was used as a template to design a second-generation library which was then screened against lipid vesicles at very high stringency. Compared to the consensus sequence from the first library, the most active second-generation peptides are highly potent, equilibrium pore-formers in synthetic lipid vesicles. Here, we use these first- and second-generation families of peptides to test the hypothesis that a large increase in potency in bacteria-like lipid vesicles will correlate with a large improvement in antimicrobial activity. The results do not support the hypothesis. Despite a 20-fold increase in potency against bacteria-like lipid vesicles, the second-generation peptides are only slightly more active against bacteria, and at the same time, are also more toxic against mammalian cells. The results suggest that a "pipeline" strategy toward the optimization of antimicrobial peptides could begin with a vesicle-based screen for identifying families with broad-spectrum activity, but will also need to include screening or optimization steps that are done under conditions that are more directly relevant to possible therapeutic applications.

  9. Lipid nanoparticles for cyclosporine A administration: development, characterization, and in vitro evaluation of their immunosuppression activity

    PubMed Central

    Guada, Melissa; Sebastián, Victor; Irusta, Silvia; Feijoó, Esperanza; Dios-Viéitez, María del Carmen; Blanco-Prieto, María José

    2015-01-01

    Cyclosporine A (CsA) is an immunosuppressant commonly used in transplantation for prevention of organ rejection as well as in the treatment of several autoimmune disorders. Although commercial formulations are available, they have some stability, bioavailability, and toxicity related problems. Some of these issues are associated with the drug or excipients and others with the dosage forms. With the aim of overcoming these drawbacks, lipid nanoparticles (LN) have been proposed as an alternative, since excipients are biocompatible and also a large amount of surfactants and organic solvents can be avoided. CsA was successfully incorporated into LN using the method of hot homogenization followed by ultrasonication. Three different formulations were optimized for CsA oral administration, using different surfactants: Tween® 80, phosphatidylcholine, taurocholate and Pluronic® F127 (either alone or mixtures). Freshly prepared Precirol nanoparticles showed mean sizes with a narrow size distribution ranging from 121 to 202 nm, and after freeze-drying were between 163 and 270 nm, depending on the stabilizer used. Surface charge was negative in all LN developed. High CsA entrapment efficiency of approximately 100% was achieved. Transmission electron microscopy was used to study the morphology of the optimized LN. Also, the crystallinity of the nanoparticles was studied by X-ray powder diffraction and differential scanning calorimetry. The presence of the drug in LN surfaces was confirmed by X-ray photoelectron spectroscopy. The CsA LN developed preserved their physicochemical properties for 3 months when stored at 4°C. Moreover, when the stabilizer system was composed of two surfactants, the LN formulations were also stable at room temperature. Finally, the new CsA formulations showed in vitro dose-dependent immuno-suppressive effects caused by the inhibition of IL-2 levels secreted from stimulated Jurkat cells. The findings obtained in this paper suggest that new lipid

  10. Influence of the lipid membrane environment on structure and activity of the outer membrane protein Ail from Yersinia pestis

    PubMed Central

    Ding, Yi; Fujimoto, L. Miya; Yao, Yong; Plano, Gregory V.; Marassi, Francesca M.

    2014-01-01

    The surrounding environment has significant consequences for the structural and functional properties of membrane proteins. While native structure and function can be reconstituted in lipid bilayer membranes, the detergents used for protein solubilization are not always compatible with biological activity and, hence, not always appropriate for direct detection of ligand binding by NMR spectroscopy. Here we describe how the sample environment affects the activity of the outer membrane protein Ail (attachment invasion locus) from Yersinia pestis. Although Ail adopts the correct β-barrel fold in micelles, the high detergent concentrations required for NMR structural studies are not compatible with the ligand binding functionality of the protein. We also describe preparations of Ail embedded in phospholipid bilayer nanodiscs, optimized for NMR studies and ligand binding activity assays. Ail in nanodiscs is capable of binding its human ligand fibronectin and also yields high quality NMR spectra that reflect the proper fold. Binding activity assays, developed to be performed directly with the NMR samples, show that ligand binding involves the extracellular loops of Ail. The data show that even when detergent micelles support the protein fold, detergents can interfere with activity in subtle ways. PMID:25433311

  11. [THE INFLUENCE OF OPIOID PEPTIDES ON LIPID PEROXIDATION AND ANTIOXIDANT ENZYME ACTIVITY IN RATS AFTER SWIMMING STRESS].

    PubMed

    Solin, A V; Lyashev, Yu D

    2015-08-01

    It was established in experiments on rats, that injection of opioid peptides DAGO (a selective igonist of opioid mu-receptors), DSLET (a selective agonist of opioid delta-receptors) or dynorpiin A (1-13) (a selective agonist of opioid kappa-receptors) decreased the stress-induced activatin of lipid peroxidation in liver tissue and plasma. A selective agonist of opioid mu-receptors) AGO manifested the most expressed activity. The using of investigating peptides caused the increase of superoxiddismutase activity in liver tissue. The reinforcement of catalase activity was )bserved in DSLET or dynorphin A (1-13). DAGO decreased its activity. The peptide effects of lifferent directions oncatalase activity in plasma were established. These effects can be explained y the stress-limiting action of peptides in entire organism, the peculiarities of opioid receptors spreading in liver tissue and by the influence of preceded load with non-complete oxidized sub stances after intensive swimming on the opioid receptor affinity.

  12. AMP-activated protein kinase: an emerging drug target to regulate imbalances in lipid and carbohydrate metabolism to treat cardio-metabolic diseases

    PubMed Central

    Srivastava, Rai Ajit K.; Pinkosky, Stephen L.; Filippov, Sergey; Hanselman, Jeffrey C.; Cramer, Clay T.; Newton, Roger S.

    2012-01-01

    The adenosine monophosphate-activated protein kinase (AMPK) is a metabolic sensor of energy metabolism at the cellular as well as whole-body level. It is activated by low energy status that triggers a switch from ATP-consuming anabolic pathways to ATP-producing catabolic pathways. AMPK is involved in a wide range of biological activities that normalizes lipid, glucose, and energy imbalances. These pathways are dysregulated in patients with metabolic syndrome (MetS), which represents a clustering of major cardiovascular risk factors including diabetes, lipid abnormalities, and energy imbalances. Clearly, there is an unmet medical need to find a molecule to treat alarming number of patients with MetS. AMPK, with multifaceted activities in various tissues, has emerged as an attractive drug target to manage lipid and glucose abnormalities and maintain energy homeostasis. A number of AMPK activators have been tested in preclinical models, but many of them have yet to reach to the clinic. This review focuses on the structure-function and role of AMPK in lipid, carbohydrate, and energy metabolism. The mode of action of AMPK activators, mechanism of anti-inflammatory activities, and preclinical and clinical findings as well as future prospects of AMPK as a drug target in treating cardio-metabolic disease are discussed. PMID:22798688

  13. [Lipid peroxidation, activity of Na+,k(+) -ATPase and exzymes of antioxidant defence in rats with nephropathy induced by cobalt chloride].

    PubMed

    Tedtoeva, A I; Dzugkoeva, F S; Mozhaeva, I V; Dzugkoev, S G

    2010-01-01

    Chronic parenteral administration of cobalt chloride (6 mg/kg) to male rats for 2 weeks or 1 month was accompanied by activation of lipid peroxidation (LPO), a decrease of superoxide dismutase activity and an increase of catalase activity. The membrane toxic action also resulted in a decrease of cortical and medullar Na+,K(+)-ATPase activity of kidneys, and the decrease in renal functions (glomerular filtration, renal water reabsorption, spontaneous diuresis, electrolyte excretion).

  14. Characterization and Inducing Melanoma Cell Apoptosis Activity of Mannosylerythritol Lipids-A Produced from Pseudozyma aphidis

    PubMed Central

    Fan, Linlin; Li, Hongji; Niu, Yongwu; Chen, Qihe

    2016-01-01

    Mannosylerythritol lipids (MELs) are natural glycolipid biosurfactants which have potential applications in the fields of food, cosmetic and medicine. In this study, MELs were produced from vegetable oil by Pseudozyma aphidis. Their structural data through LC/MS, GC/MS and NMR analysis revealed that MEL-A with two acetyls was the major compound and the identified homologs of MEL-A contained a length of C8 to C14 fatty acid chains. This glycolipid exhibited a surface tension of 27.69 mN/m at a critical micelle concentration (CMC), self-assembling into particles in the water solution. It was observed to induce cell growth-inhibition and apoptosis of B16 melanoma cells in a dose-dependent manner, as well as cause cell cycle arrest at the S phase. Further quantitative RT-PCR analysis and western blotting revealed an increasing tendency of both mRNA and protein expressions of Caspase-12, CHOP, GRP78 and Caspase-3, and a down-regulation of protein Bcl-2. Combined with the up regulation of signaling IRE1 and ATF6, it can be speculated that MEL-A-induced B16 melanoma cell apoptosis was associated with the endoplasmic reticulum stress (ERS). PMID:26828792

  15. Evaluation of antiradical activity of different cocoa and chocolate products: relation with lipid and protein composition.

    PubMed

    Vertuani, Silvia; Scalambra, Emanuela; Vittorio, Trotta; Bino, Alessia; Malisardi, Gemma; Baldisserotto, Anna; Manfredini, Stefano

    2014-04-01

    Chocolate antioxidant properties are often claimed; however, they are frequently different from the parent natural sources due to the industry or artisan transformation. In particular, antioxidant property of chocolate and cocoa are not adequately taken into consideration by consumers who normally make use of this food just for its flavor and taste properties. In this study, we have investigated the antioxidant capacity and total phenolic content of cocoa nibs, cocoa masses, and corresponding chocolate bars with different percentages of cocoa from different origins. The antioxidant capacity of the different samples was measured by two different assays [1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) and ferric reducing antioxidant of potency (FRAP) tests]. The Folin-Ciocalteu reagent was used to assess the total phenolic content. The masses showed a higher antioxidant power than the nibs, and this has been attributed to the fact that in the nibs is still present the lipid part, which will form the cocoa butter. The influence of milk, whey, and soy proteins was also investigated. Our results showed that the extra dark cocoa bar, 100% cocoa chocolate, is the best in terms of total polyphenol content and in terms of antioxidant capacity according to the DPPH and FRAP tests. In addition, the bars of organic dark chocolate 80%, dark Tanzania 80%, and Trinidad 80% products are well performing in all respects. As highlighted by us, the antiradical properties of cocoa products are higher than many antioxidant supplements in tablets.

  16. Evaluation of Antiradical Activity of Different Cocoa and Chocolate Products: Relation with Lipid and Protein Composition

    PubMed Central

    Vertuani, Silvia; Scalambra, Emanuela; Vittorio, Trotta; Bino, Alessia; Malisardi, Gemma; Baldisserotto, Anna

    2014-01-01

    Abstract Chocolate antioxidant properties are often claimed; however, they are frequently different from the parent natural sources due to the industry or artisan transformation. In particular, antioxidant property of chocolate and cocoa are not adequately taken into consideration by consumers who normally make use of this food just for its flavor and taste properties. In this study, we have investigated the antioxidant capacity and total phenolic content of cocoa nibs, cocoa masses, and corresponding chocolate bars with different percentages of cocoa from different origins. The antioxidant capacity of the different samples was measured by two different assays [1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) and ferric reducing antioxidant of potency (FRAP) tests]. The Folin–Ciocalteu reagent was used to assess the total phenolic content. The masses showed a higher antioxidant power than the nibs, and this has been attributed to the fact that in the nibs is still present the lipid part, which will form the cocoa butter. The influence of milk, whey, and soy proteins was also investigated. Our results showed that the extra dark cocoa bar, 100% cocoa chocolate, is the best in terms of total polyphenol content and in terms of antioxidant capacity according to the DPPH and FRAP tests. In addition, the bars of organic dark chocolate 80%, dark Tanzania 80%, and Trinidad 80% products are well performing in all respects. As highlighted by us, the antiradical properties of cocoa products are higher than many antioxidant supplements in tablets. PMID:24433077

  17. Effect of boric acid on antioxidant enzyme activity, lipid peroxidation, and ultrastructure of midgut and fat body of Galleria mellonella.

    PubMed

    Büyükgüzel, Ender; Büyükgüzel, Kemal; Snela, Milena; Erdem, Meltem; Radtke, Katarzyna; Ziemnicki, Kazimierz; Adamski, Zbigniew

    2013-04-01

    Boric acid is widely used as an insecticide, acaricide, herbicide, and fungicide and also during various industrial processings. Hence, numerous populations are subjects to this toxic compound. Its action on animals is still not fully known and understood. We examined the effect of boric acid on larvae of greater wax moth (Galleria mellonella). The chemical appeared to be toxic for larvae, usually in a concentration-dependent manner. Exposed groups revealed increased lipid peroxidation and altered activity of catalase, superoxide dismutase, glutathione S-transferase, and glutathione peroxidase. We also observed changes of ultrastructure, which were in tune with biochemical assays. We suggest that boric acid has a broad mode of action, which may affect exposed larvae, and even if sublethal, they may lead to disturbances within exposed populations.

  18. Glucosamine found as a substituent of both phosphate groups in Bordetella lipid A backbones: role of a BvgAS-activated ArnT ortholog.

    PubMed

    Marr, Nico; Tirsoaga, Alina; Blanot, Didier; Fernandez, Rachel; Caroff, Martine

    2008-06-01

    Endotoxins are amphipathic lipopolysaccharides (LPSs), major constituents of the outer membrane of gram-negative bacteria. They consist of a lipid region, covalently linked to a core oligosaccharide, to which may be linked a repetitive glycosidic chain carrying antigenic determinants. Most of the biological activities of endotoxins have been associated with the lipid moiety of the molecule: unique to gram-negative bacteria, LPS is a ligand of the mammalian TLR4-MD2-CD14 pathogen recognition receptor complex. Lipid A preparations are often heterogeneous with respect to both the numbers and the lengths of fatty acids and the natures of substituents on the phosphate groups when present. The variants can significantly affect host immune responses. Nine species in the Bordetella genus have been described, and the fine LPS structures of seven of them have been published. In this report, lipids A from Bordetella pertussis Tohama I and B. bronchiseptica strain 4650 were further characterized and revealed to have a glucosamine substituting both lipid A phosphate groups of the diglucosamine backbone. These substitutions have not been previously described for bordetellae. Moreover, a B. pertussis transposon mutation that maps within a gene encoding a Bordetella ArnT (formerly PmrK) glycosyl transferase ortholog does not carry this substitution, thus providing a genetic basis for the modification. Reverse transcriptase PCR of this locus showed that it is Bvg regulated, suggesting that the ability of Bordetella to modify lipid A via this glucosamine modification is a potential virulence trait.

  19. Structural variations of the cell wall precursor lipid II and their influence on binding and activity of the lipoglycopeptide antibiotic oritavancin.

    PubMed

    Münch, Daniela; Engels, Ina; Müller, Anna; Reder-Christ, Katrin; Falkenstein-Paul, Hildegard; Bierbaum, Gabriele; Grein, Fabian; Bendas, Gerd; Sahl, Hans-Georg; Schneider, Tanja

    2015-02-01

    Oritavancin is a semisynthetic derivative of the glycopeptide antibiotic chloroeremomycin with activity against Gram-positive pathogens, including vancomycin-resistant staphylococci and enterococci. Compared to vancomycin, oritavancin is characterized by the presence of two additional residues, a hydrophobic 4'-chlorobiphenyl methyl moiety and a 4-epi-vancosamine substituent, which is also present in chloroeremomycin. Here, we show that oritavancin and its des-N-methylleucyl variant (des-oritavancin) effectively inhibit lipid I- and lipid II-consuming peptidoglycan biosynthesis reactions in vitro. In contrast to that for vancomycin, the binding affinity of oritavancin to the cell wall precursor lipid II appears to involve, in addition to the D-Ala-D-Ala terminus, other species-specific binding sites of the lipid II molecule, i.e., the crossbridge and D-isoglutamine in position 2 of the lipid II stem peptide, both characteristic for a number of Gram-positive pathogens, including staphylococci and enterococci. Using purified lipid II and modified lipid II variants, we studied the impact of these modifications on the binding of oritavancin and compared it to those of vancomycin, chloroeremomycin, and des-oritavancin. Analysis of the binding parameters revealed that additional intramolecular interactions of oritavancin with the peptidoglycan precursor appear to compensate for the loss of a crucial hydrogen bond in vancomycin-resistant strains, resulting in enhanced binding affinity. Augmenting previous findings, we show that amidation of the lipid II stem peptide predominantly accounts for the increased binding of oritavancin to the modified intermediates ending in D-Ala-D-Lac. Corroborating our conclusions, we further provide biochemical evidence for the phenomenon of the antagonistic effects of mecA and vanA resistance determinants in Staphylococcus aureus, thus partially explaining the low frequency of methicillin-resistant S. aureus (MRSA) acquiring high

  20. Effect of detergents and endogenous lipids on the activity and properties of tyrosinase and its related proteins.

    PubMed

    Jiménez-Cervantes, C; García-Borrón, J C; Lozano, J A; Solano, F

    1995-04-13

    Within mammalian melanocytes, melanin biosynthesis is controlled by three enzymes structurally related: tyrosinase and two tyrosinase related proteins, TRP1 and TRP2. These melanosomal enzymes are integral membrane proteins with a carboxyl tail oriented to the cytoplasm, a single membrane-spanning helix and the bulk of the protein located inside the melanosome. Their solubilization is usually carried out by treatment of melanosomal preparations with non-ionic detergents, but, so far, no comparative study of the effect of the detergents employed on the properties of the solubilized proteins has been reported. We have compared the effect of the detergents Brij-35, Nonidet P-40, Tween-20, sodium deoxycholate and Triton X-114 on several properties of the melanogenic enzymes, including the solubilization yield, stability, electrophoretic behaviour and accessibility of epitopes located in the carboxyl tail to specific antibodies. Our data indicate that not only the total amount of enzymes solubilized, but also their relative proportions in the solubilized preparations depend on the detergent used. The non-ionic detergents apparently interact strongly with the melanogenic enzymes, affecting their mobility in SDS-PAGE, and might induce different conformations of the carboxyl tail. Complete replacement of lipids by the detergents results in a decreased stability that can be partially reversed by the addition of endogenous lipids. This treatment also produces a noticeable activation of the tyrosinase isoenzymes, which is higher for TRP1 than for tyrosinase. Taken together, these data show that the transmembrane and carboxyl fragments of the proteins of the tyrosinase family might modulate the stability and activity of the melanogenic enzymes.

  1. Peptidoglycan-mediated IL-8 expression in human alveolar type II epithelial cells requires lipid raft formation and MAPK activation.

    PubMed

    Cheon, In Su; Woo, Sang Su; Kang, Seok-Seong; Im, Jintaek; Yun, Cheol-Heui; Chung, Dae Kyun; Park, Dong Ki; Han, Seung Hyun

    2008-03-01

    Staphylococcus aureus, a major sepsis-causing Gram-positive bacterium, invades pulmonary epithelial cells and causes lung diseases. In the lung, alveolar type II epithelial cells play an important role in innate immunity by secreting chemokines and antimicrobial peptides upon bacterial infection whereas type I cells mainly function in gas-exchange. In this study, we investigated the ability of S. aureus peptidoglycan (PGN) to induce expression of a chemokine, IL-8, in a human alveolar type II epithelial cell line, A549. PGN induces IL-8 mRNA and protein expression in a dose- and time-dependent manner. Supplementation of soluble CD14 further enhanced the PGN-induced IL-8 expression. Interestingly, PGN-induced IL-8 expression was inhibited by nystatin, a specific inhibitor for lipid rafts, but not by chlorpromazine, a specific inhibitor for clathrin-coated pits. Furthermore, PGN-induced IL-8 expression was attenuated by inhibitors for MAP kinases such as ERK, p38 kinase, and JNK/SAPK, whereas no inhibitory effect was observed by inhibitors for reactive oxygen species or protein kinase C. Electrophoretic mobility shift assay demonstrates that PGN increased the DNA binding of the transcription factors, AP-1 and NF-kappaB while minimally, NF-IL6, all of which are involved in the transcription of IL-8. Taken together, these results suggest that PGN induces IL-8 expression in a CD14-enhanced manner in human alveolar type II epithelial cells, through the formation of lipid rafts and the activation of MAP kinases, which ultimately leads to activation of AP-1, NF-kappaB, and NF-IL6.

  2. Antioxidant Activity of Allium hookeri Root Extract and Its Effect on Lipid Stability of Sulfur-fed Pork Patties

    PubMed Central

    2015-01-01

    This study was performed to assess the antioxidant activity of Allium hookeri root extract (AHE) on lipid oxidation of raw sulfur-fed pork patties for 14 d of refrigerated storage. Different concentration of ethanol (0-100%) and time (1-12 h) were applied to determine the extraction condition. Water (0% ethanol) extraction for 1 h was selected as an optimal extraction condition of AHE for the following study showing the highest total phenolic content and total flavonoid content, as well as the strongest antioxidant activity. The 1% AHE (SP1), 3% AHE (SP2), and 0.05% ascorbic acid (SP3) were added into sulfur-fed pork patties against controls; SP0 (sulfur-fed pork patties with no AHE) and P0 (normal pork patties with no AHE). The pH values of P0 and SP0 significantly increased (p<0.05) than others on 14 d and redness of P0 showed the largest decrement during storage. P0 and SP0 showed higher production of conjugated dienes on d 7 than others (p<0.05). Thiobarbituric acid reactive substances (TBARS) values were decreased in proportion to the increased level of AHE on 14 d (p<0.05) resulting in higher TBARS values on P0 and SP0 (p<0.05) and the negative correlation between AHE level and TBARS were also demonstrated (r=-0.910, p=0.001). Therefore, the results suggest that AHE effectively retarded the lipid oxidation rate of sulfur-fed pork patties indicating the potential usage of AHE as a natural preservative. PMID:26761799

  3. Metabolism. Part III: Lipids.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Describes the metabolic processes of complex lipids, including saponification, activation and transport, and the beta-oxidation spiral. Discusses fatty acid degradation in regard to biochemical energy and ketone bodies. (TW)

  4. Lipid and Carbohydrate Modifications of α-Galactosylceramide Differently Influence Mouse and Human Type I Natural Killer T Cell Activation.

    PubMed

    Birkholz, Alysia; Nemčovič, Marek; Yu, Esther Dawen; Girardi, Enrico; Wang, Jing; Khurana, Archana; Pauwels, Nora; Farber, Elisa; Chitale, Sampada; Franck, Richard W; Tsuji, Moriya; Howell, Amy; Van Calenbergh, Serge; Kronenberg, Mitchell; Zajonc, Dirk M

    2015-07-10

    The ability of different glycosphingolipids (GSLs) to activate type I natural killer T cells (NKT cells) has been known for 2 decades. The possible therapeutic use of these GSLs has been studied in many ways; however, studies are needed in which the efficacy of promising GSLs is compared under identical conditions. Here, we compare five unique GSLs structurally derived from α-galactosylceramide. We employed biophysical and biological assays, as well as x-ray crystallography to study the impact of the chemical modifications of the antigen on type I NKT cell activation. Although all glycolipids are bound by the T cell receptor of type I NKT cells in real time binding assays with high affinity, only a few activate type I NKT cells in in vivo or in vitro experiments. The differences in biological responses are likely a result of different pharmacokinetic properties of each lipid, which carry modifications at different parts of the molecule. Our results indicate a need to perform a variety of assays to ascertain the therapeutic potential of type I NKT cell GSL activators.

  5. Gestational diabetes mellitus (GDM) decreases butyrylcholinesterase (BChE) activity and changes its relationship with lipids

    PubMed Central

    Guimarães, Larissa O.; de Andrade, Fabiana A.; Bono, Gleyse F.; Setoguchi, Thaís E.; Brandão, Mariana B.; Chautard-Freire-Maia, Eleidi A.; dos Santos, Izabella C.R.; Picheth, Geraldo; Faria, Ana Cristina R. de A.; Réa, Rosângela R.; Souza, Ricardo L.R.; Furtado-Alle, Lupe

    2014-01-01

    Many conditions interfere with butyrylcholinesterase (BChE) activity, e.g., pregnancy or presence of the BCHE gene variant −116A can decrease activity whereas obesity and types I and II diabetes mellitus can increase activity. In this study, we examined BChE activity, −116A and 1615A BCHE gene variants, and anthropometric and biochemical variables associated with diabetes in patients with gestational diabetes mellitus (GDM) and in healthy pregnant women. BChE activity was measured spectrophotometrically using propionylthiocholine as substrate and genotyping of the −116 and 1615 sites of the BCHE gene was done with a TaqMan SNP genotyping assay. Three groups were studied: 150 patients with GDM, 295 healthy pregnant women and 156 non-pregnant healthy women. Mean BChE activity was significantly lower in healthy pregnant women than in women from the general population and was further reduced in GDM patients. BChE activity was significantly reduced in carriers of −116A in GDM patients and healthy pregnant women. Although GDM patients had a significantly higher mean body mass index (BMI) and triglycerides than healthy pregnant women, they had lower mean BChE activity, suggesting that the lowering effect of GDM on BChE activity was stronger than the characteristic enhancing effect of increased BMI and triglycerides. PMID:24688284

  6. Correlation of serum triglyceride and its reduction by omega-3 fatty acids with lipid transfer activity and the neutral lipid compositions of high-density and low-density lipoproteins.

    PubMed

    Pownall, H J; Brauchi, D; Kilinç, C; Osmundsen, K; Pao, Q; Payton-Ross, C; Gotto, A M; Ballantyne, C M

    1999-04-01

    Serum triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) concentrations are inversely correlated and mechanistically linked by means of lipid transfer activities. Phospholipid transfer activity (PLTA) moves phospholipids among serum lipoproteins; cholesteryl ester transfer activity (CETA), which exchanges cholesteryl esters (CE) and TG among lipoproteins, is stimulated by nonesterified fatty acids (NEFA). The aims of this study were (a) to develop a quantitative model that correlates the neutral lipid (NL = CE + TG) compositions of HDL and LDL with serum TG concentration; (b) identify the serum lipid determinants of CETA and PLTA, and; (c) identify the effects of serum TG reductions on the neutral lipid compositions of HDL and LDL, serum NEFA concentrations, and on PLTA and CETA. These aims were addressed in 40 hypertriglyceridemic subjects before and after treatment with an 85% concentrate of omega-3 fatty acids (Omacor) and in 16 untreated normolipidemic subjects. In vivo, the NL compositions of LDL and HDL were described by a mathematical model having the form of adsorption isotherms: HDL - (TG/NL) = (0.90 +/- 0.07) serum TG/(7.0 +/- 1.2 mmol/l + serum TG) and LDL - (TG/NL) = (0.65 +/- 0.08) serum TG/(4.9 +/- 1.5 mmol/l + serum TG). Reduction of serum TG was associated with reductions in HDL - (TG/NL), serum NEFA concentration, and serum CETA but not PLTA. These data suggest that both hypertriglyceridemia and the attendant elevated serum CETA but not PLTA are determinants of HDL and LDL composition and structure and that serum TG concentrations are good predictors of the NL compositions of HDL and LDL.

  7. [The effect of periodontal cytomedin on free-radical lipid oxidation and on antiaggregation activity in the periodontium in chronic stress].

    PubMed

    Silenko, Iu I; Mishchenko, V P; Tokar', D L; Khavinson, V Kh; Popsuĭko, G I

    1994-01-01

    Effects of polypeptide bioregulators isolated from periodontal tissue on free-radical oxidation of lipids and the microcirculatory hemostasis during the development of chronic stress were under study. Increased reactions of lipid free-radical oxidation and blood hydrocortisone levels, denudation of dental necks were observed in animals during stress, which was explained by disordered reaction of microcirculatory hemostasis assessed from the antiaggregation activity of the periodontium. Administration of a polypeptide bioregulator led to a reduction of free-radical oxidation of lipids, to an increase in the activities of antioxidative enzymes, and hence, to a reduction of the injury to the cellular structures of the periodontium due to decrease of disorders of the microcirculatory hemostasis and ischemia in it.

  8. Mitochondrial lipids in neurodegeneration.

    PubMed

    Aufschnaiter, Andreas; Kohler, Verena; Diessl, Jutta; Peselj, Carlotta; Carmona-Gutierrez, Didac; Keller, Walter; Büttner, Sabrina

    2017-01-01

    Mitochondrial dysfunction is a common feature of many neurodegenerative diseases, including proteinopathies such as Alzheimer's or Parkinson's disease, which are characterized by the deposition of aggregated proteins in the form of insoluble fibrils or plaques. The distinct molecular processes that eventually result in mitochondrial dysfunction during neurodegeneration are well studied but still not fully understood. However, defects in mitochondrial fission and fusion, mitophagy, oxidative phosphorylation and mitochondrial bioenergetics have been linked to cellular demise. These processes are influenced by the lipid environment within mitochondrial membranes as, besides membrane structure and curvature, recruitment and activity of different proteins also largely depend on the respective lipid composition. Hence, the interaction of neurotoxic proteins with certain lipids and the modification of lipid composition in different cell compartments, in particular mitochondria, decisively impact cell death associated with neurodegeneration. Here, we discuss the relevance of mitochondrial lipids in the pathological alterations that result in neuronal demise, focussing on proteinopathies.

  9. Keys to Lipid Selection in Fatty Acid Amide Hydrolase Catalysis: Structural Flexibility, Gating Residues and Multiple Binding Pockets

    PubMed Central

    Palermo, Giulia; Bauer, Inga; Campomanes, Pablo; Cavalli, Andrea; Armirotti, Andrea; Girotto, Stefania; Rothlisberger, Ursula; De Vivo, Marco

    2015-01-01

    The fatty acid amide hydrolase (FAAH) regulates the endocannabinoid system cleaving primarily the lipid messenger anandamide. FAAH has been well characterized over the years and, importantly, it represents a promising drug target to treat several diseases, including inflammatory-related diseases and cancer. But its enzymatic mechanism for lipid selection to specifically hydrolyze anandamide, rather than similar bioactive lipids, remains elusive. Here, we clarify this mechanism in FAAH, examining the role of the dynamic paddle, which is formed by the gating residues Phe432 and Trp531 at the boundary between two cavities that form the FAAH catalytic site (the “membrane-access” and the “acyl chain-binding” pockets). We integrate microsecond-long MD simulations of wild type and double mutant model systems (Phe432Ala and Trp531Ala) of FAAH, embedded in a realistic membrane/water environment, with mutagenesis and kinetic experiments. We comparatively analyze three fatty acid substrates with different hydrolysis rates (anandamide > oleamide > palmitoylethanolamide). Our findings identify FAAH’s mechanism to selectively accommodate anandamide into a multi-pocket binding site, and to properly orient the substrate in pre-reactive conformations for efficient hydrolysis that is interceded by the dynamic paddle. Our findings therefore endorse a structural framework for a lipid selection mechanism mediated by structural flexibility and gating residues between multiple binding cavities, as found in FAAH. Based on the available structural data, this exquisite catalytic strategy for substrate specificity seems to be shared by other lipid-degrading enzymes with similar enzymatic architecture. The mechanistic insights for lipid selection might assist de-novo enzyme design or drug discovery efforts. PMID:26111155

  10. Effects of acute exposure to the radiofrequency fields of cellular phones on plasma lipid peroxide and antioxidase activities in human erythrocytes.

    PubMed

    Moustafa, Y M; Moustafa, R M; Belacy, A; Abou-El-Ela, S H; Ali, F M

    2001-11-01

    Radiofrequency fields of cellular phones may affect biological systems by increasing free radicals, which appear mainly to enhance lipid peroxidation, and by changing the antioxidase activities of human blood thus leading to oxidative stress. To test this, we have investigated the effect of acute exposure to radiofrequency fields of commercially available cellular phones on some parameters indicative of oxidative stress in 12 healthy adult male volunteers. Each volunteer put the phone in his pocket in standby position with the keypad facing the body. The parameters measured were lipid peroxide and the activities of superoxide dismutase (SOD), total glutathione peroxidase (GSH-Px) and catalase. The results obtained showed that the plasma level of lipid peroxide was significantly increased after 1, 2 and 4 h of exposure to radiofrequency fields of the cellular phone in standby position. Moreover, the activities of SOD and GSH-Px in human erythrocytes showed significant reduction while the activity of catalase in human erythrocytes did not decrease significantly. These results indicate that acute exposure to radiofrequency fields of commercially available cellular phones may modulate the oxidative stress of free radicals by enhancing lipid peroxidation and reducing the activation of SOD and GSH-Px, which are free radical scavengers. Therefore, these results support the interaction of radiofrequency fields of cellular phones with biological systems.

  11. The mouse liver displays daily rhythms in the metabolism of phospholipids and in the activity of lipid synthesizing enzymes.

    PubMed

    Gorné, Lucas D; Acosta-Rodríguez, Victoria A; Pasquaré, Susana J; Salvador, Gabriela A; Giusto, Norma M; Guido, Mario Eduardo

    2015-02-01

    The circadian system involves central and peripheral oscillators regulating temporally biochemical processes including lipid metabolism; their disruption leads to severe metabolic diseases (obesity, diabetes, etc). Here, we investigated the temporal regulation of glycerophospholipid (GPL) synthesis in mouse liver, a well-known peripheral oscillator. Mice were synchronized to a 12:12 h light-dark (LD) cycle and then released to constant darkness with food ad libitum. Livers collected at different times exhibited a daily rhythmicity in some individual GPL content with highest levels during the subjective day. The activity of GPL-synthesizing/remodeling enzymes: phosphatidate phosphohydrolase 1 (PAP-1/lipin) and lysophospholipid acyltransferases (LPLATs) also displayed significant variations, with higher levels during the subjective day and at dusk. We evaluated the temporal regulation of expression and activity of phosphatidylcholine (PC) synthesizing enzymes. PC is mainly synthesized through the Kennedy pathway with Choline Kinase (ChoK) as a key regulatory enzyme or through the phosphatidylethanolamine (PE) N-methyltransferase (PEMT) pathway. The PC/PE content ratio exhibited a daily variation with lowest levels at night, while ChoKα and PEMT mRNA expression displayed maximal levels at nocturnal phases. Our results demonstrate that mouse liver GPL metabolism oscillates rhythmically with a precise temporal control in the expression and/or activity of specific enzymes.

  12. Passive and active strategies for transdermal delivery using co-encapsulating nanostructured lipid carriers: in vitro vs. in vivo studies.

    PubMed

    Vitorino, Carla; Almeida, António; Sousa, João; Lamarche, Isabelle; Gobin, Patrice; Marchand, Sandrine; Couet, William; Olivier, Jean-Christophe; Pais, Alberto

    2014-02-01

    This work aimed at designing a formulation based on nanostructured lipid carriers (NLC) for transdermal co-administration of olanzapine and simvastatin, using passive and active strategies in a combined in vitro/in vivo development approach. NLC were prepared by two distinct methods, namely solvent emulsification-evaporation (SE/E) and high pressure homogenization (HPH). HPH was selected on the basis of a better performance in terms of drug loading and in vitro permeation rate. Several mathematical models were used to elucidate the release mechanisms from lipid nanoparticles. In vitro release kinetics was shown to be driven by diffusion, but other mechanisms were also present, and supported the feasibility of using NLC for sustained drug delivery. The in vitro skin studies showed that the chemical penetration enhancers, limonene and ethanol, added to the NLC formulations, promoted a synergistic permeation enhancement of both drugs, with olanzapine exhibiting a higher permeation than simvastatin. Transdermal administration to rats resulted in steady-state levels reached at around 10h and maintained for 48h, again with olanzapine exhibiting a better permeation rate. The pharmacokinetic parameters indicated that the NLC dispersion displayed a better in vivo performance than the gel, which was consistent with the in vitro results. These differences were, however, negligible in the flux values, supporting the use of gel as a final, more convenient, formulation. The in vivo experiments in rats correlated well with in vitro findings and revealed that the combined use of ethanol and limonene, incorporated in the NLC formulation, provided the main driving force for drug permeation. The Dermaroller® pretreatment did not significantly enhance drug permeation, supporting the use of passive methods as suitable for a transdermal delivery system. Furthermore, this work may provide a promising proof-of-concept for further clinical application in the treatment of schizophrenia and

  13. Introduction to membrane lipids.

    PubMed

    Epand, Richard M

    2015-01-01

    Biological membranes are composed largely of lipids and proteins. The most common arrangement of lipids in biological membranes is as a bilayer. This arrangement spontaneously forms a barrier for the passage of polar materials. The bilayer is thin but can have a large area in the dimension perpendicular to its thickness. The physical nature of the bilayer membrane will vary according to the conditions of the environment as well as the chemical structure of the lipid constituents of the bilayer. These physical properties determine the function of the membrane together with specific structural features of the lipids that allow them to have signaling properties. The lipids of the membrane are not uniformly distributed. There is an intrinsic asymmetry between the two monolayers that constitute the bilayer. In addition, some lipids tend to be enriched in particular regions of the membrane, termed domains. There is evidence that certain domains recruit specific proteins into that domain. This has been suggested to be important for allowing interaction among different proteins involved in certain signal transduction pathways. Membrane lipids have important roles in determining the physical properties of the membrane, in modulating the activity of membrane-bound proteins and in certain cases being specific secondary messengers that can interact with specific proteins. A large variety of lipids present in biological membranes result in them possessing many functions.

  14. Time course of changes in serum glucose, insulin, lipids and tissue lipase activities in macrosomic offspring of rats with streptozotocin-induced diabetes.

    PubMed

    Merzouk, H; Madani, S; Chabane Sari, D; Prost, J; Bouchenak, M; Belleville, J

    2000-01-01

    The aim of this investigation was to determine the time course of changes in serum glucose, insulin and lipid levels, as well as lipid and protein content and lipolytic activities in insulin target organs (liver, adipose tissue and muscle), in macrosomic offspring of streptozotocin-induced mildly hyperglycaemic rats. Food intake and nutritional efficiency were also evaluated. Mild hyperglycaemia in pregnant rats was induced by intraperitoneal injection of streptozotocin (40 mg/kg body weight) on day 5 of gestation. Control pregnant rats were injected with citrate buffer. At birth, macrosomic pups (birth weight >1.7 S.D. greater than the mean value for the control pups) had higher serum insulin, glucose and lipid levels than control pups. These macrosomic rats maintained accelerated postnatal growth combined with high adipose tissue weight up to 12 weeks of age. These rats were not hyperphagic; however, they had higher food efficiency and fat storage capacity with higher adipocyte lipoprotein lipase activity, which contributed to persisting obesity. Hepatic lipase activity was increased in macrosomic rats at all ages. Moreover, macrosomia was associated with metabolic disturbances that varied according to age and sex. After 1 month, several alterations observed at birth had disappeared. Serum glucose, insulin and lipid levels in male and female macrosomic rats became similar to those of their respective controls. At 2 months of age, hepatic and serum triacylglycerol levels were higher in macrosomic females than in controls. By 3 months, macrosomic rats (both males and females) had developed insulin resistance with hyperinsulinaemia, hyperglycaemia, and higher serum and hepatic lipids. In conclusion, macrosomia was associated with alterations in glucose and lipid metabolism through to adulthood. It should be considered as an important potential risk factor for obesity and its metabolic complications.

  15. Hepatic mTORC1 controls locomotor activity, body temperature, and lipid metabolism through FGF21.

    PubMed

    Cornu, Marion; Oppliger, Wolfgang; Albert, Verena; Robitaille, Aaron M; Trapani, Francesca; Quagliata, Luca; Fuhrer, Tobias; Sauer, Uwe; Terracciano, Luigi; Hall, Michael N

    2014-08-12

    The liver is a key metabolic organ that controls whole-body physiology in response to nutrient availability. Mammalian target of rapamycin (mTOR) is a nutrient-activated kinase and central controller of growth and metabolism that is negatively regulated by the tumor suppressor tuberous sclerosis complex 1 (TSC1). To investigate the role of hepatic mTOR complex 1 (mTORC1) in whole-body physiology, we generated liver-specific Tsc1 (L-Tsc1 KO) knockout mice. L-Tsc1 KO mice displayed reduced locomotor activity, body temperature, and hepatic triglyceride content in a rapamycin-sensitive manner. Ectopic activation of mTORC1 also caused depletion of hepatic and plasma glutamine, leading to peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α)-dependent fibroblast growth factor 21 (FGF21) expression in the liver. Injection of glutamine or knockdown of PGC-1α or FGF21 in the liver suppressed the behavioral and metabolic defects due to mTORC1 activation. Thus, mTORC1 in the liver controls whole-body physiology through PGC-1α and FGF21. Finally, mTORC1 signaling correlated with FGF21 expression in human liver tumors, suggesting that treatment of glutamine-addicted cancers with mTOR inhibitors might have beneficial effects at both the tumor and whole-body level.

  16. Hepatic mTORC1 controls locomotor activity, body temperature, and lipid metabolism through FGF21

    PubMed Central

    Cornu, Marion; Oppliger, Wolfgang; Albert, Verena; Robitaille, Aaron M.; Trapani, Francesca; Quagliata, Luca; Fuhrer, Tobias; Sauer, Uwe; Terracciano, Luigi; Hall, Michael N.

    2014-01-01

    The liver is a key metabolic organ that controls whole-body physiology in response to nutrient availability. Mammalian target of rapamycin (mTOR) is a nutrient-activated kinase and central controller of growth and metabolism that is negatively regulated by the tumor suppressor tuberous sclerosis complex 1 (TSC1). To investigate the role of hepatic mTOR complex 1 (mTORC1) in whole-body physiology, we generated liver-specific Tsc1 (L-Tsc1 KO) knockout mice. L-Tsc1 KO mice displayed reduced locomotor activity, body temperature, and hepatic triglyceride content in a rapamycin-sensitive manner. Ectopic activation of mTORC1 also caused depletion of hepatic and plasma glutamine, leading to peroxisome proliferator–activated receptor γ coactivator-1α (PGC-1α)–dependent fibroblast growth factor 21 (FGF21) expression in the liver. Injection of glutamine or knockdown of PGC-1α or FGF21 in the liver suppressed the behavioral and metabolic defects due to mTORC1 activation. Thus, mTORC1 in the liver controls whole-body physiology through PGC-1α and FGF21. Finally, mTORC1 signaling correlated with FGF21 expression in human liver tumors, suggesting that treatment of glutamine-addicted cancers with mTOR inhibitors might have beneficial effects at both the tumor and whole-body level. PMID:25082895

  17. Antitumor activity of tripterine via cell-penetrating peptide-coated nanostructured lipid carriers in a prostate cancer model

    PubMed Central

    Yuan, Ling; Liu, Congyan; Chen, Yan; Zhang, Zhenhai; Zhou, Lei; Qu, Ding

    2013-01-01

    Background The purpose of this study was to evaluate the antitumor effect of cell-penetrating peptide-coated tripterine-loaded nanostructured lipid carriers (CT-NLC) on prostate tumor cells in vitro and in vivo. Methods CT-NLC were developed to improve the hydrophilicity of tripterine. The antiproliferative effects of CT-NLC, tripterine-loaded nanostructured lipid carriers (T-NLC), and free tripterine in a human prostatic carcinoma cell line (PC-3) and a mouse prostate carcinoma cell line (RM-1) were evaluated using an MTT assay. The advantage of CT-NLC over T-NLC and free tripterine with regard to antitumor activity in vivo was evaluated in a prostate tumor-bearing mouse model. The induced tumor necrosis factor-alpha and interleukin-6 cytokine content was investigated by enzyme-linked immunosorbent assay to determine the effect of CT-NLC, T-NLC, and free tripterine on immune responses. Histologic and TUNEL assays were carried out to investigate the mechanisms of tumor necrosis and apoptosis. Results CT-NLC, T-NLC, and free tripterine showed high antiproliferative activity in a dose-dependent manner, with an IC50 of 0.60, 0.81, and 1.02 μg/mL in the PC-3 cell line and 0.41, 0.54, and 0.89 μg/mL in the RM-1 cell line after 36 hours. In vivo, the tumor inhibition rates for cyclophosphamide, high-dose (4 mg/kg) and low-dose (2 mg/kg) tripterine, high-dose (4 mg/kg) and low-dose (2 mg/kg) T-NLC, high-dose (4 mg/kg) and low-dose (2 mg/kg) CT-NLC were 76.51%, 37.07%, 29.53%, 63.56%, 48.25%, 72.68%, and 54.50%, respectively, showing a dose-dependent pattern. The induced tumor necrosis factor-alpha and interleukin-6 cytokine content after treatment with CT-NLC and T-NLC was significantly higher than that of high-dose tripterine. Moreover, CT-NLC showed the expected advantage of inducing necrosis and apoptosis in prostate tumor cells. Conclusion CT-NLC noticeably enhanced antitumor activity in vitro and in vivo and showed dramatically improved cytotoxicity in normal cells

  18. Effects of temperature on oxidative stress defense systems, lipid peroxidation and lipoxygenase activity in Phalaenopsis.

    PubMed

    Ali, Mohammad Babar; Hahn, Eun-Joo; Paek, Kee-Yoeup

    2005-03-01

    Higher plants growing in natural environments experience various abiotic stresses. The aim of this study was to determine whether exposure to temperature-stress would lead to oxidative stress and whether this effect varied with different exposure periods. The thermal dependencies of the activities of protective enzymes, photosynthetic efficiency (Fv/Fm), protein, non-protein thiol (NP-SH), cysteine content, lipoxygenase (LOX) activity (EC 1.13.11.12) and malondialdehyde (MDA) content at 25-40 degrees C were determined for 4, 24 and 48 h in leaf and root segments of Phalaenopsis. The increase in MDA level and LOX activity may be due to temperature-associated oxidative damage to leaf and root segments. Temperature-stress induced not only activities of active oxygen species (AOS) scavenging enzymes but also protein, NP-SH and cysteine content in both leaf and root segments at 30 degrees C for 4 and 24 h (except for 48 h in some cases) compared to 25 degrees C-and greenhouse-grown leaf and root segments indicating that antioxidants enzymes played an important role in protecting plant from temperature-stress. However, activities of dehydroascorbate reductase (DHAR, EC 1.8.5.1), glutathione peroxidase (GPX, EC 1.11.1.9) and glutathione-S-transferase (GST, EC 2.5.1.18) in leaf and root, glutathione reductase (GR, EC 1.6.4.2) in leaf and guaiacol peroxidase (G-POD, 1.11.1.7) in root segments were induced significantly at 40 degrees C compared to 25 degrees C and greenhouse-grown plants suggesting that these enzymes play protective roles at high temperature. In contrast, activities of superoxide dismutase (SOD, EC 1.15.1.1) and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) in leaf and root, catalase (CAT, EC 1.11.1.6) in root, GR in root, and protein, cysteine, NP-SH content in both root and leaf and Fv/Fm ratio were diminished significantly at 40 degrees C compared to 25 degrees C-and greenhouse-grown plants. These indicate that these enzymes were apparently not

  19. Phytol directly activates peroxisome proliferator-activated receptor {alpha} (PPAR{alpha}) and regulates gene expression involved in lipid metabolism in PPAR{alpha}-expressing HepG2 hepatocytes

    SciTech Connect

    Goto, Tsuyoshi; Takahashi, Nobuyuki; Kato, Sota; Egawa, Kahori; Ebisu, Shogo; Moriyama, Tatsuya; Fushiki, Tohru; Kawada, Teruo . E-mail: fat@kais.kyoto-u.ac.jp

    2005-11-18

    The peroxisome proliferator-activated receptor (PPAR) is one of the indispensable transcription factors for regulating lipid metabolism in various tissues. In our screening for natural compounds that activate PPAR using luciferase assays, a branched-carbon-chain alcohol (a component of chlorophylls), phytol, has been identified as a PPAR{alpha}-specific activator. Phytol induced the increase in PPAR{alpha}-dependent luciferase activity and the degree of in vitro binding of a coactivator, SRC-1, to GST-PPAR{alpha}. Moreover, the addition of phytol upregulated the expression of PPAR{alpha}-target genes at both mRNA and protein levels in PPAR{alpha}-expressing HepG2 hepatocytes. These findings indicate that phytol is functional as a PPAR{alpha} ligand and that it stimulates the expression of PPAR{alpha}-target genes in intact cells. Because PPAR{alpha} activation enhances circulating lipid clearance, phytol may be important in managing abnormalities in lipid metabolism.

  20. Effect of Carissa opaca leaves extract on lipid peroxidation, antioxidant activity and reproductive hormones in male rats

    PubMed Central

    2013-01-01

    Background Carissa opaca leaves are traditionally used in the treatment of male dysfunction and hormonal disorder as well as in oxidative stress in Pakistan and Asia. The present study was designed to assess the protective effects of methanolic extract of Carissa opaca leaves (MLC) on carbon tetrachloride (CCl4)-induced reproductive stress in male rats and bioactive constituents responsible for the activity. Methods CCl4 was induced in 42 male rats for eight weeks and checked the protective efficacy of methanolic extract of Carissa opaca leaves at various hormonal imbalances, alteration of antioxidant enzymes, DNA fragmentation levels and lipid peroxidation caused testicular fibrosis in testis while High performance Liquid Chromatography (HPLC) was used for detection of bioactive components. Results HPLC characterization revealed the presence of isoquercitin , hyperoside , vitexin , myricetin and kaempherol. CCl4 caused significant alteration in the secretion of reproductive hormones. Activity of antioxidant enzymes viz; catalase, superoxide dimutase and phase II metabolizing enzymes including glutathione peroxidase, glutathione reductase and reduced glutathione was decreased while DNA fragmentation, hydrogen per oxide contents and thiobarbituric acid reactive substances (TBARS) were increased with CCl4 treatment. Co-administration of 100 mg/kg and 200 mg/kg b.w. MLC effectively ameliorated the alterations in the biochemical markers; hormonal and molecular levels. Conclusion Protective effects of methanolic extract of Carissa opaca against CCl4−induced antioxidant and hormonal dysfunction which might be due to bioactive compound present in extract. PMID:23786717

  1. The effects of dietary boric acid and borax supplementation on lipid peroxidation, antioxidant activity, and DNA damage in rats.

    PubMed

    Ince, Sinan; Kucukkurt, Ismail; Cigerci, Ibrahim Hakki; Fatih Fidan, A; Eryavuz, Abdullah

    2010-07-01

    The aims of this study were to clarify the effects of high dietary supplementation with boric acid and borax, called boron (B) compounds, on lipid peroxidation (LPO), antioxidant activity, some vitamin levels, and DNA damage in rats. Thirty Sprague Dawley male rats were divided into three equal groups: the animals in the first group (control) were fed with a standard rodent diet containing 6.4 mg B/kg, and the animals in the experimental group were fed with a standard rodent diet added with a supra-nutritional amount of boric acid and borax (100 mg B/kg) throughout the experimental period of 28 days. The B compounds decreased malondialdehyde (MDA), DNA damage, the protein carbonyl content (PCO) level in blood, and glutathione (GSH) concentration in the liver, Cu-Zn superoxide dismutase (SOD), and catalase (CAT) activity in the kidney. The B compounds increased GSH concentration in blood and the vitamin C level in plasma. Consequently, our results demonstrate that B supplementation (100 mg/kg) in diet decreases LPO, and enhances the antioxidant defense mechanism and vitamin status. There are no differences in oxidant/antioxidant balance and biochemical parameters except for serum vitamin A and liver GSH concentration, between the boron compounds used in this study.

  2. Solid lipid nanoparticles co-loaded with simazine and atrazine: preparation, characterization, and evaluation of herbicidal activity.

    PubMed

    de Oliveira, Jhones Luiz; Campos, Estefânia Vangelie Ramos; Gonçalves da Silva, Camila Morais; Pasquoto, Tatiane; Lima, Renata; Fraceto, Leonardo Fernandes

    2015-01-21

    Solid lipid nanoparticles (SLN) containing the herbicides atrazine and simazine were prepared and characterized, and in vitro evaluation was made of the release kinetics, herbicidal activity, and cytotoxicity. The stability of the nanoparticles was investigated over a period of 120 days, via analyses of particle size, ζ potential, polydispersion, pH, and encapsulation efficiency. SLN showed good physicochemical stability and high encapsulation efficiencies. Release kinetics tests showed that use of SLN modified the release profiles of the herbicides in water. Herbicidal activity assays performed with pre- and postemergence treatment of the target species Raphanus raphanistrum showed the effectiveness of the formulations of nanoparticles containing herbicides. Assays with nontarget organisms (Zea mays) showed that the formulations did not affect plant growth. The results of cytotoxicity assays indicated that the presence of SLN acted to reduce the toxicity of the herbicides. The new nanoparticle formulations enable the use of smaller quantities of herbicide and therefore offer a more environmentally friendly method of controlling weeds in agriculture.

  3. Miconazole-loaded nanostructured lipid carriers (NLC) for local delivery to the oral mucosa: improving antifungal activity.

    PubMed

    Mendes, A I; Silva, A C; Catita, J A M; Cerqueira, F; Gabriel, C; Lopes, C M

    2013-11-01

    Miconazole is a widely used antifungal agent with poor aqueous solubility, which requires the development of drug delivery systems able to improve its therapeutic activity. For this purpose, a miconazole-loaded nanostructured lipid carriers (NLC) dispersion was prepared and characterized. Further, the dispersion was used to prepare a NLC-based hydrogel formulation proposed as an alternative system to improve the local delivery of miconazole to the oral mucosa. NLC dispersion showed particles in the nanometer range (≈ 200 nm) with low polidispersity index (<0.3), good physical stability and high encapsulation efficiency (>87%). A controlled miconazole release was observed from NLC and NLC-based hydrogel formulations, in contrast to a commercial oral gel formulation, which demonstrated a faster release. Additionally, it was observed that the encapsulation of miconazole in the NLC improved its antifungal activity against Candida albicans. Therefore, it was demonstrated that the encapsulation of miconazole in NLC allows for obtaining the same therapeutic effect of a commercial oral gel formulation, using a 17-fold lower dose of miconazole.

  4. Behaviour of Saccharomyces cerevisiae wine strains during adaptation to unfavourable conditions of fermentation on synthetic medium: cell lipid composition, membrane integrity, viability and fermentative activity.

    PubMed

    Mannazzu, Ilaria; Angelozzi, Daniele; Belviso, Simona; Budroni, Marilena; Farris, Giovanni Antonio; Goffrini, Paola; Lodi, Tiziana; Marzona, Mario; Bardi, Laura

    2008-01-15

    During must fermentation wine strains are exposed to a variety of biotic and abiotic stresses which, when prevailing over the cellular defence systems, can affect cell viability with negative consequences on the progression of the fermentative process. To investigate the ability of wine strains to survive and adapt to unfavourable conditions of fermentation, the lipid composition, membrane integrity, cell viability and fermentative activity of three strains of Saccharomyces cerevisiae were analysed during hypoxic growth in a sugar-rich medium lacking lipid nutrients. These are stressful conditions, not unusual during must fermentation, which, by affecting lipid biosynthesis may exert a negative effect on yeast viability. The results obtained showed that the three strains were able to modulate cell lipid composition during fermentation. However, only two of them, which showed highest viability and membrane integrity at the end of the fermentation process, reached a fatty acid composition which seemed to be optimal for a successful adaptation. In particular, C16/TFA and UFA/TFA ratios, more than total lipid and ergosterol contents, seem to be involved in yeast adaptation.

  5. Effect of the nature of the spacer on gene transfer efficacies of novel thiocholesterol derived gemini lipids in different cell lines: a structure-activity investigation.

    PubMed

    Bajaj, Avinash; Kondaiah, Paturu; Bhattacharya, Santanu

    2008-04-24

    A structure-activity investigation was undertaken to see the effect of the nature of the spacer on the gene transfection efficacies of thiocholesterol-derived cationic gemini lipids possessing disulfide linkage between the cationic headgroup and the thiocholesterol moiety. Three gemini cationic lipids possessing hydrophobic flexible (-(CH 2) 5-; 1), hydrophobic rigid (-C 6H 4-; 2), and hydrophilic flexible (-CH 2-CH 2-O-CH 2-CH 2-; 3) spacer segments were synthesized. In HeLa cells, lipid formulations 1 and 2 were found to be more effective as compared to lipid 3 formulation. In HT1080 cell line, the order of transfectability was 3 > 1 > 2. Transfection studies in HeLa and HT1080 cell line also showed 40-50% transfection efficacy in the presence of 10% serum conditions. These formulations were also able to transfect gene across difficult cells like HaCaT. Cytotoxic studies showed the nontoxic nature of these lipid-DNA complexes at different N/P ratios used for transfection studies.

  6. Effects of the PPARα agonist WY-14,643 on plasma lipids, enzymatic activities and mRNA expression of lipid metabolism genes in a marine flatfish, Scophthalmus maximus.

    PubMed

    Urbatzka, R; Galante-Oliveira, S; Rocha, E; Lobo-da-Cunha, A; Castro, L F C; Cunha, I

    2015-07-01

    Fibrates and other lipid regulator drugs are widespread in the aquatic environment including estuaries and coastal zones, but little is known on their chronic effects on non-target organisms as marine fish. In the present study, turbot juveniles were exposed to the PPARα model agonist WY-14,643 for 21 days by repeated injections at the concentrations of 5mg/kg (lo-WY) and 50mg/kg (hi-WY), and samples taken after 7 and 21 days. Enzyme activity and mRNA expression of palmitoyl-CoA oxidase and catalase in the liver were analyzed as first response, which validated the experiment by demonstrating interactions with the peroxisomal fatty acid oxidation and oxidative stress pathways in the hi-WY treatment. In order to get mechanistic insights, alterations of plasma lipids (free cholesterol, FC; HDL associated cholesterol, C-HDL; triglycerides, TG; non-esterified fatty acids, NEFA) and hepatic mRNA expression of 17 genes involved in fatty acid and lipid metabolism were studied. The exposure to hi-WY reduced the quantity of plasma FC, C-HDL, and NEFA. Microsomal triglyceride transfer protein and apolipoprotein E mRNA expression were higher in hi-WY, and indicated an increased formation of VLDL particles and energy mobilization from liver. It is speculated that energy depletion by PPARα agonists may contribute to a higher susceptibility to environmental stressors.

  7. 2-Benzoxazolinone (BOA) induced oxidative stress, lipid peroxidation and changes in some antioxidant enzyme activities in mung bean (Phaseolus aureus).

    PubMed

    Batish, D R; Singh, H P; Setia, N; Kaur, S; Kohli, R K

    2006-01-01

    2-Benzoxazolinone (BOA), a well-known allelochemical with strong phytotoxicity, is a potential herbicidal candidate. The aim of the present study was to determine whether phytotoxicity of BOA is due to induction of oxidative stress caused by generation of reactive oxygen species (ROS) and the changes in levels of antioxidant enzymes induced in response to BOA. Effect of BOA was studied on electrolyte leakage, lipid peroxidation (LP), hydrogen peroxide (H(2)O(2)) generation, proline (PRO) accumulation, and activities of antioxidant enzymes-superoxide dismutase (SOD, 1.15.1.1), ascorbate peroxidase (APX, 1.11.1.11), guaiacol peroxidase (GPX, 1.11.1.7), catalase (CAT, 1.11.1.6) and glutathione reductase (GR, 1.6.4.2) in Phaseolus aureus (mung bean). BOA significantly enhanced malondialdehyde (MDA) content, a product of LP, in both leaves and roots of mung bean. The amount of H(2)O(2), a product of oxidative stress, and endogenous PRO increased many-fold in response to BOA. Accumulation of PRO, MDA and H(2)O(2) indicates the cellular damage in the target tissue caused by ROS generated by BOA. In response to BOA, there was a significant increase in the activities of scavenging enzymes SOD, APX, GPX, CAT, and GR in root and leaf tissue of mung bean. At 5 mM BOA, GR activity in roots showed a nearly 22-fold increase over that in control. The present study concludes that BOA induces oxidative stress in mung bean through generation of ROS and upregulation of activities of various scavenging enzymes.

  8. The impact of cationic solid lipid nanoparticles on human neutrophil activation and formation of neutrophil extracellular traps (NETs).

    PubMed

    Hwang, Tsong-Long; Aljuffali, Ibrahim A; Hung, Chi-Feng; Chen, Chun-Han; Fang, Jia-You

    2015-06-25

    Cationic solid lipid nanoparticles (cSLNs) are extensively employed as the nanocarriers for drug/gene targeting to tumors and the brain. Investigation into the possible immune response of cSLNs is still lacking. The aim of this study was to evaluate the impact of cSLNs upon the activation of human polymorphonuclear neutrophil cells (PMNs). The cytotoxicity, pro-inflammatory mediators, Ca(2+) mobilization, mitogen-activated protein kinases (MAPKs), and neutrophil extracellular traps (NETs) as the indicators of PMN stimulation were examined in this work. The cSLNs presented a diameter of 195 nm with a zeta potential of 44 mV. The cSLNs could interact with the cell membrane to produce a direct membrane lysis and the subsequent cytotoxicity according to lactate dehydrogenase (LDH) elevation. The interaction of cSLNs with the membrane also triggered a Ca(2+) influx, followed by the induction of oxidative stress and degranulation. The cationic nanoparticles elevated the levels of superoxide anion and elastase by 24- and 9-fold, respectively. The PMN activation by cSLNs promoted the phosphorylation of p38 and Jun-N-terminal kinases (JNK) but not extracellular signal-regulated kinases (ERK). The imaging of scanning electron microscopy (SEM) and immunofluorescence demonstrated the production of NETs by cSLNs. This phenomenon was not significant for the neutral SLNs (nSLNs), although histones in NETs also increased after treatment of nSLNs. Our results suggest an important role of cSLNs in governing the activation of human neutrophils.

  9. Impact of purification conditions and history on A2A adenosine receptor activity: The role of CHAPS and lipids

    DOE PAGES

    Naranjo, Andrea N.; McNeely, Patrick M.; Katsaras, John; ...

    2016-05-27

    The adenosine A2A receptor (A2AR) is a much-studied class A G protein-coupled receptor (GPCR). For biophysical studies, A2AR is commonly purified in a detergent mixture of dodecylmaltoside (DDM), 3-(3-cholamidopropyl) dimethylammoniopropane sulfonate (CHAPS), and cholesteryl hemisuccinate (CHS). Here we studied the effects of CHAPS on the ligand binding activity and stability of wild type, full-length human A2AR. We also tested the cholesterol requirement for maintaining the active conformation of the receptor when solubilized in detergent micelles. To this end, the receptor was purified using DDM, DDM/CHAPS, or the short hydrocarbon chain lipid 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC, di-6:0PC). After solubilization in DDM, DDM/CHAPS, ormore » DHPC micelles, although A2AR was found to retain its native-like fold, its binding ability was significantly compromised compared to DDM or DDM/CHAPS with CHS. It therefore appears that although cholesterol is not needed for A2AR to retain a native-like, α-helical conformation, it may be a critical component for high affinity ligand binding. Further, this result suggests that the conformational differences between the active and inactive protein may be so subtle that commonly used spectroscopic methods are unable to differentiate between the two forms, highlighting the need for activity measurements. Furthermore, the studies presented in this paper also underline the importance of the protein’s purification history; i.e., detergents that interact with the protein during purification affect the ligand binding properties of the receptor in an irreversible manner.« less

  10. A Model for the Interfacial Kinetics of Phospholipase D Activity on Long-Chain Lipids

    DTIC Science & Technology

    2013-07-01

    activity. MATERIALS AND METHODS Materials We purchased cesium acetate, cyclosporin A, and 1-octadecanethiol from Sigma Aldrich (St. Louis, MO... cesium chloride (CsCl) from International Biotechnologies (New Haven, CT); and calcium chloride (CaCl2), pentane, and hexadecane from Fluka. gA was...sn- glycero-3-phosphate ( sodium salt) (DiPhyPA). PLD from cabbage (EC 3.1.4.4) was obtained from Sigma Aldrich. Storage and final concentration of PLD

  11. Effect of vitamin E and selenium supplementation of cockerel diets on glutathione peroxidase activity and lipid peroxidation susceptibility in sperm, testes, and liver.

    PubMed

    Surai, P; Kostjuk, I; Wishart, G; Macpherson, A; Speake, B; Noble, R; Ionov, I; Kutz, E

    1998-01-01

    The phospholipids of avian spermatozoa are characterized by high proportions of arachidonic (20:4n-6) and docosatetraenoic (22:4n-6) fatty acids and are therefore sensitive to lipid peroxidation. Alpha-tocopherol and glutathione peroxidase [GSH-Px] are believed to be the primary components of the antioxidant system of the spermatozoa. The present study evaluates the effect of vitamin E and vitamin E plus Se supplementation of the cockerel diet on GSH-Px activity, vitamin E accumulation, and lipid peroxidation in the spermatozoa, testes, and liver. At the beginning of the experiment 75 Rhode Island Red cockerels were divided into five groups, kept in individual cages, and fed a wheat-barley-based ration balanced in all nutrients. Supplements fed to the different groups were as follows: vitamin E, 0, 20, 200, 20, and 200 mg/kg to groups 1-5, respectively, with groups 4 and 5 also receiving 0. 3 mg Se/kg. The vitamin E supplementation produced increased levels of alpha-tocopherol in semen, testes, and liver. The inclusion of the Se into the cock diet had a significant (P < 0.01) stimulating effect on GSH-Px activity in seminal plasma, spermatozoa, testes, and liver. The increased vitamin E concentration in the spermatozoa was associated with a reduction in their susceptibility to lipid peroxidation. Similarly, the increased GSH-Px activity provided enhanced protection against lipid peroxidation.

  12. Use of the parallax-quench method to determine the position of the active-site loop of cholesterol oxidase in lipid bilayers.

    PubMed

    Chen, X; Wolfgang, D E; Sampson, N S

    2000-11-07

    To elucidate the cholesterol oxidase-membrane bilayer interaction, a cysteine was introduced into the active site lid at position-81 using the Brevibacterium enzyme. To eliminate the possibility of labeling native cysteine, the single cysteine in the wild-type enzyme was mutated to a serine without any change in activity. The loop-cysteine mutant was then labeled with acrylodan, an environment-sensitive fluorescence probe. The fluorescence increased and blue-shifted upon binding to lipid vesicles, consistent with a change into a more hydrophobic, i.e., lipid, environment. This acrylodan-labeled cholesterol oxidase was used to explore the pH, ionic strength, and headgroup dependence of binding. Between pH 6 and 10, there was no significant change in binding affinity. Incorporation of anionic lipids (phosphatidylserine) into the vesicles did not increase the binding affinity nor did altering the ionic strength. These experiments suggested that the interactions are primarily driven by hydrophobic effects not ionic effects. Using vesicles doped with either 5-doxyl phosphatidylcholine, 10-doxyl phosphatidylcholine, or phosphatidyl-tempocholine, quenching of acrylodan fluorescence was observed upon binding. Using the parallax method of London [Chattopadhyay, A., and London, E. (1987) Biochemistry 26, 39-45], the acrylodan ring is calculated to be 8.1 +/- 2.5 A from the center of the lipid bilayer. Modeling the acrylodan-cysteine residue as an extended chain suggests that the backbone of the loop does not penetrate into the lipid bilayer but interacts with the headgroups, i.e., the choline. These results demonstrate that cholesterol oxidase interacts directly with the lipid bilayer and sits on the surface of the membrane.

  13. Dietary freshwater clam (Corbicula fluminea) extract suppresses accumulation of hepatic lipids and increases in serum cholesterol and aminotransferase activities induced by dietary chloretone in rats.

    PubMed

    Chijimatsu, Takeshi; Umeki, Miki; Kobayashi, Satoru; Kataoka, Yutaro; Yamada, Koji; Oda, Hiroaki; Mochizuki, Satoshi

    2015-01-01

    We investigated the ameliorative effect of freshwater clam extract (FCE) on fatty liver, hypercholesterolemia, and liver injury in rats exposed to chloretone. Furthermore, we examined the effects of major FCE components (fat and protein fractions) to determine the active components in FCE. Chloretone increased serum aminotransferase activities and led to hepatic lipid accumulation. Serum aminotransferase activities and hepatic lipid content were lower in rats fed total FCE or fat/protein fractions of FCE. Expression of fatty acid synthase and fatty acid desaturase genes was upregulated by chloretone. Total FCE and fat/protein fractions of FCE suppressed the increase in gene expression involved in fatty acid synthesis. Serum cholesterol levels increased twofold upon chloretone exposure. Total FCE or fat/protein fractions of FCE showed hypocholesterolemic effects in rats with hypercholesterolemia induced by chloretone. These suggest that FCE contains at least two active components against fatty liver, hypercholesterolemia, and liver injury in rats exposed to chloretone.

  14. Fatty acids and retinoids control lipid metabolism through activation of peroxisome proliferator-activated receptor-retinoid X receptor heterodimers.

    PubMed Central

    Keller, H; Dreyer, C; Medin, J; Mahfoudi, A; Ozato, K; Wahli, W

    1993-01-01

    The nuclear hormone receptors called PPARs (peroxisome proliferator-activated receptors alpha, beta, and gamma) regulate the peroxisomal beta-oxidation of fatty acids by induction of the acyl-CoA oxidase gene that encodes the rate-limiting enzyme of the pathway. Gel retardation and cotransfection assays revealed that PPAR alpha heterodimerizes with retinoid X receptor beta (RXR beta; RXR is the receptor for 9-cis-retinoic acid) and that the two receptors cooperate for the activation of the acyl-CoA oxidase gene promoter. The strongest stimulation of this promoter was obtained when both receptors were exposed simultaneously to their cognate activators. Furthermore, we show that natural fatty acids, and especially polyunsaturated fatty acids, activate PPARs as potently as does the hypolipidemic drug Wy 14,643, the most effective activator known so far. Moreover, we discovered that the synthetic arachidonic acid analogue 5,8,11,14-eicosatetraynoic acid is 100 times more effective than Wy 14,643 in the activation of PPAR alpha. In conclusion, our data demonstrate a convergence of the PPAR and RXR signaling pathways in the regulation of the peroxisomal beta-oxidation of fatty acids by fatty acids and retinoids. Images Fig. 1 Fig. 2 PMID:8384714

  15. Reviewing and identifying amino acids of human, murine, canine and equine TLR4 / MD-2 receptor complexes conferring endotoxic innate immunity activation by LPS/lipid A, or antagonistic effects by Eritoran, in contrast to species-dependent modulation by lipid IVa.

    PubMed

    Scior, Thomas; Alexander, Christian; Zaehringer, Ulrich

    2013-01-01

    There is literature evidence gathered throughout the last two decades reflecting unexpected species differences concerning the immune response to lipid IVa which provides the opportunity to gain more detailed insight by the molecular modeling approach described in this study. Lipid IVa is a tetra-acylated precursor of lipid A in the biosynthesis of lipopolysaccharide (LPS) in Gram-negative bacteria. Lipid A of the prototypic E. coli-type is a hexa-acylated structure that acts as an agonist in all tested mammalian species by innate immunorecognition via the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD-2) receptor complex. In contrast, lipid IVa is proinflammatory in mouse cells (agonism) but it remains inactive to human macrophages and even antagonizes the action of potent agonists like E. coli-type lipid A. This particular ambivalent activity profile of lipid IVa has been confirmed in other mammalian species: in equine cells Lipid IVa also acts in a weak agonistic manner, whereas being inactive and antagonizing the lipid A-induced activation of canine TLR4/MD-2. Intriguingly, the respective TLR4 amino acid sequences of the latter species are more identical to the human (67%, 68%) than to the murine (62%, 58%) ortholog. In order to address the unpaired activity-sequence dualism for human, murine, canine and equine species regarding the activity of lipid IVa as compared to LPS and lipid A and, we review the literature and computationally pinpoint the differential biological effects of lipid IVa versus LPS and lipid A to specific amino acid residues. In contrast to lipid IVa the structurally related synthetic compound Eritoran (E5564) acts consistently in an antagonistic manner in these mammalian species and serves as a reference ligand for molecular modeling in this study. The combined evaluation of data sets provided by prior studies and in silico homology mapping of differential residues of TLR4/MD-2 complexes lends detailed insight into the

  16. Lipid metabolism enzyme 5-LOX and its metabolite LTB4 are capable of activating transcription factor NF-{kappa}B in hepatoma cells

    SciTech Connect

    Zhao, Yu; Wang, Wenhui; Wang, Qi; Zhang, Xiaodong; Ye, Lihong

    2012-02-24

    Highlights: Black-Right-Pointing-Pointer 5-LOX is able to upregulate expression of NF-{kappa}B p65. Black-Right-Pointing-Pointer 5-LOX enhances nuclear translocation of NF-{kappa}B p65 via increasing p-I{kappa}B-{alpha} level. Black-Right-Pointing-Pointer 5-LOX stimulates transcriptional activity of NF-{kappa}B in hepatoma cells. Black-Right-Pointing-Pointer LTB4 activates transcriptional activity of NF-{kappa}B in hepatoma cells. -- Abstract: The issue that lipid metabolism enzyme and its metabolites regulate transcription factors in cancer cell is not fully understood. In this study, we first report that the lipid metabolism enzyme 5-Lipoxygenase (5-LOX) and its metabolite leukotriene B4 (LTB4) are capable of activating nuclear factor-{kappa}B (NF-{kappa}B) in hepatoma cells. We found that the treatment of MK886 (an inhibitor of 5-LOX) or knockdown of 5-LOX was able to downregulate the expression of NF-{kappa}B p65 at the mRNA level and decreased the phosphorylation level of inhibitor {kappa}B{alpha} (I{kappa}B{alpha}) in the cytoplasm of hepatoma HepG2 or H7402 cells, which resulted in the decrease of the level of nuclear NF-{kappa}B p65. These were confirmed by immunofluorescence staining in HepG2 cell. Moreover, the above treatments were able to decrease the transcriptional activity of NF-{kappa}B in the cells. The LTB4, one of metabolites of 5-LOX, is responsible for 5-LOX-activated NF-{kappa}B in a dose-dependent manner. Thus, we conclude that the lipid metabolism enzyme 5-LOX and its metabolite LTB4 are capable of activating transcription factor NF-{kappa}B in hepatoma cells. Our finding provides new insight into the significance of lipid metabolism in activation of transcription factors in cancer.

  17. Specific binding of nisin to the peptidoglycan precursor lipid II combines pore formation and inhibition of cell wall biosynthesis for potent antibiotic activity.

    PubMed

    Wiedemann, I; Breukink, E; van Kraaij, C; Kuipers, O P; Bierbaum, G; de Kruijff, B; Sahl, H G

    2001-01-19

    Unlike numerous pore-forming amphiphilic peptide antibiotics, the lantibiotic nisin is active in nanomolar concentrations, which results from its ability to use the lipid-bound cell wall precursor lipid II as a docking molecule for subsequent pore formation. Here we use genetically engineered nisin variants to identify the structural requirements for the interaction of the peptide with lipid II. Mutations affecting the conformation of the N-terminal part of nisin comprising rings A through C, e.g. [S3T]nisin, led to reduced binding and increased the peptide concentration necessary for pore formation. The binding constant for the S3T mutant was 0.043 x 10(7) m(-1) compared with 2 x 10(7) m(-1) for the wild-type peptide, and the minimum concentration for pore formation increased from the 1 nm to the 50 nm range. In contrast, peptides mutated in the flexible hinge region, e.g. [DeltaN20/DeltaM21]nisin, were completely inactive in the pore formation assay, but were reduced to some extent in their in vivo activity. We found the remaining in vivo activity to result from the unaltered capacity of the mutated peptide to bind to lipid II and thus to inhibit its incorporation into the peptidoglycan network. Therefore, through interaction with the membrane-bound cell wall precursor lipid II, nisin inhibits peptidoglycan synthesis and forms highly specific pores. The combination of two killing mechanisms in one molecule potentiates antibiotic activity and results in nanomolar MIC values, a strategy that may well be worth considering for the construction of novel antibiotics.

  18. Cutting edge: nonglycosidic CD1d lipid ligands activate human and murine invariant NKT cells.

    PubMed

    Silk, Jonathan D; Salio, Mariolina; Reddy, B Gopal; Shepherd, Dawn; Gileadi, Uzi; Brown, James; Masri, S Hajar; Polzella, Paolo; Ritter, Gerd; Besra, Gurdyal S; Jones, E Yvonne; Schmidt, Richard R; Cerundolo, Vincenzo

    2008-05-15

    Invariant NKT cells (iNKT cells) recognize CD1d/glycolipid complexes. We demonstrate that the nonglycosidic compound threitolceramide efficiently activates iNKT cells, resulting in dendritic cell (DC) maturation and the priming of Ag-specific T and B cells. Threitolceramide-pulsed DCs are more resistant to iNKT cell-dependent lysis than alpha-galactosylceramide-pulsed DCs due to the weaker affinity of the human iNKT TCR for CD1d/ threitolceramide than CD1d/alpha-galactosylceramide complexes. iNKT cells stimulated with threitolceramide also recover more quickly from activation-induced anergy. Kinetic and functional experiments showed that shortening or lengthening the threitol moiety by one hydroxymethylene group modulates ligand recognition, as human and murine iNKT cells recognize glycerolceramide and arabinitolceramide differentially. Our data broaden the range of potential iNKT cell agonists. The ability of these compounds to assist the priming of Ag-specific immune responses while minimizing iNKT cell-dependent DC lysis makes them attractive adjuvants for vaccination strategies.

  19. Wedelolactone Regulates Lipid Metabolism and Improves Hepatic Steatosis Partly by AMPK Activation and Up-Regulation of Expression of PPARα/LPL and LDLR

    PubMed Central

    Yang, Li-chao; Xu, Xu-dong; Li, Wei-jie; Luo, Xiu-mei; Jin, Xin

    2015-01-01

    Hyperlipidemia is considered one of the greatest risk factors of cardiovascular diseases. We investigated the anti-hyperlipidemic effect and the underlying mechanism of wedelolactone, a plant-derived coumestan, in HepG2 cells and high-fat diet (HFD)−induced hyperlipidemic hamsters. We showed that in cultured HepG2 cells, wedelolactone up-regulated protein levels of adenosine monophosphate activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-alpha (PPARα) as well as the gene expression of AMPK, PPARα, lipoprotein lipase (LPL), and the low-density lipoprotein receptor (LDLR). Meanwhile, administration of wedelolactone for 4 weeks decreased the lipid profiles of plasma and liver in HFD−induced hyperlipidemic hamsters, including total cholesterol (TC), triglycerides (TG), and low-density lipoprotein-cholesterol (LDL-C). The activation of AMPK and up-regulation of PPARα was also observed with wedelolactone treatment. Furthermore, wedelolactone also increased the activities of superoxidase dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased the level of the lipid peroxidation product malondialdehyde (MDA) in the liver, therefore decreasing the activity of alanine aminotransferase (ALT). In conclusion, we provide novel experimental evidence that wedelolactone possesses lipid-lowering and steatosis-improving effects, and the underlying mechanism is, at least in part, mediated by the activation of AMPK and the up-regulation of PPARα/LPL and LDLR. PMID:26168156

  20. Dill seed extract improves abnormalities in lipid metabolism through peroxisome proliferator-activated receptor-α (PPAR-α) activation in diabetic obese mice.

    PubMed

    Takahashi, Nobuyuki; Yao, Lan; Kim, Minji; Sasako, Hiroshi; Aoyagi, Morihiro; Shono, Jinji; Tsuge, Nobuaki; Goto, Tsuyoshi; Kawada, Teruo

    2013-07-01

    Dill, a small annual herb, is widely used as a flavoring agent in dishes including salads. It has been demonstrated that dill extract and its essential oil show hypolipidemic effects in rats. However, the mechanism of these effects has not been elucidated yet. We found that dill seed extract (DSE) activated peroxisome proliferator-activated receptor-α (PPAR-α), an indispensable regulator for hepatic lipid metabolism, by luciferase assay. Thus, we performed DSE feeding experiments using diabetic obese model KK-Ay mice to examine the effects of DSE on PPAR-α activation in vivo. A 4-week feeding of DSE contained in a high-fat diet decreased plasma triacylglyceride and glucose levels and increased the mRNA expression levels of fatty acid oxidation-related genes in the liver. In addition, the DSE feeding as well as bezafibrate (a PPAR-α potent agonist) feeding increased oxygen consumption rate and rectal temperature. These results indicate that DSE suppresses high-fat diet-induced hyperlipidemia through hepatic PPAR-α activation.

  1. Dual modulation of both lipid oxidation and synthesis by peroxisome proliferator-activated receptor-gamma coactivator-1alpha and -1beta in cultured myotubes.

    PubMed

    Espinoza, Daniel O; Boros, Laszlo G; Crunkhorn, Sarah; Gami, Hiral; Patti, Mary-Elizabeth

    2010-04-01

    The peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) family is a key regulator of mitochondrial function, and reduced mRNA expression may contribute to muscle lipid accumulation in obesity and type 2 diabetes. To characterize the effects of PGC-1 on lipid metabolism, we overexpressed PGC-1alpha and PGC-1beta in C2C12 myotubes using adenoviral vectors. Both PGC-1alpha and -1beta increased palmitate oxidation [31% (P<0.01) and 26% (P<0.05), respectively] despite reductions in cellular uptake [by 6% (P<0.05) and 21% (P<0.001)]. Moreover, PGC-1alpha and -1beta increased mRNA expression of genes regulating both lipid oxidation (e.g., CPT1b and ACADL/M) and synthesis (FAS, CS, ACC1/2, and DGAT1). To determine the net effect, we assessed lipid composition in PGC-1-expressing cells. Total lipid content decreased by 42% in palmitate-loaded serum-starved cells overexpressing PGC-1alpha (P<0.05). In contrast, in serum-replete cells, total lipid content was not significantly altered, but fatty acids C14:0, C16:0, C18:0, and C18:1 were increased 2- to 4-fold for PGC-1alpha/beta (P<0.05). Stable isotope-based dynamic metabolic profiling in serum-replete cells labeled with (13)C substrates revealed both increased de novo fatty acid synthesis from glucose and increased fatty acid synthesis by chain elongation with either PGC-1alpha or -1beta expression. These results indicate that PGC-1 can promote both lipid oxidation and synthesis, with net balance determined by the nutrient/hormonal environment.-Espinoza, D. O., Boros, L. G., Crunkhorn, S., Gami, H., Patti, M.-E. Dual Modulation of both lipid oxidation and synthesis by peroxisome proliferator-activated receptor-gamma coactivator-1alpha and -1beta in cultured myotubes.

  2. Life-history evolution and the microevolution of intermediary metabolism: activities of lipid-metabolizing enzymes in life-history morphs of a wing-dimorphic cricket.

    PubMed

    Zera, Anthony J; Zhao, Zhangwu

    2003-03-01

    Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100-400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride flight fuel (40% greater in LW[f]). Consistently higher activity of each enzyme in LW(f) versus SW-selected lines, and strong co-segregation between morph and enzyme activity, demonstrated genetically based co-variance between wing morph and enzyme activity. Developmental profiles of enzyme activities strongly paralleled profiles of triglyceride accumulation during adulthood and previous measures of in vivo lipid biosynthesis. These data strongly imply that genetically based elevation in activities of lipogenic enzymes, and enzymes controlling the conversion of amino acids into lipids, is an important cause underlying the elevated accumulation of triglyceride in the LW(f) morph, a key biochemical component of the trade-off between elevated early fecundity and flight capability. Global changes in lipid and amino-acid metabolism appear to have resulted from microevolutionary alteration of regulators of metabolism. Finally, strong genotype x environment (diet) interactions were observed for most enzyme activities. Future progress in understanding the functional causes of life-history evolution requires a more detailed synthesis of the fields of life-history evolution and metabolic biochemistry. Wing polymorphism is a powerful experimental model in such integrative studies.

  3. A Recipe Composed of Chinese Herbal Active Components Regulates Hepatic Lipid Metabolism of NAFLD In Vivo and In Vitro

    PubMed Central

    Meng, Sheng-xi; Liu, Qian; Tang, Ya-jun; Wang, Wen-jing; Zheng, Qing-shan; Tian, Hua-jie; Yao, Dong-sheng; Liu, Lin; Peng, Jing-hua; Zhao, Yu; Hu, Yi-yang; Feng, Qin

    2016-01-01

    This study is to investigate the therapeutic effects of the recipe composed of Atractylodes macrocephala polysaccharide, chlorogenic acid, and geniposide (named ACG) on experimental nonalcoholic fatty liver (NAFL). The research was divided into two parts as screening experiment and verification experiment. In the screening experiment, we used high-fat diet (HFD) induced NAFL rat model and uniform design to get the recipe from five Chinese herbal active components. In the verification experiment, HFD induced fatty liver rat and mouse NAFL models and free fatty acid (FFA) induced HepG2 cell model were used to verify the effects of ACG. According to the multiple regression equation of the hepatic triglyceride (TG) contents of each group in the screening experiment, the recipe ACG was obtained and the doses of Atractylodes macrocephala polysaccharide, chlorogenic acid, and geniposide for rats were 266.67, 3.33, and 45 mg/kg, respectively. The results of verification experiment verified that ACG could significantly reduce hepatic TG contents of NAFL rats and mice, as well as the cellular TG content of FFA-induced HepG2 cells. ACG could also improve HOMA-IR and hepatic mitochondrial ultrastructure of NAFL mice. Our study verified that ACG recipe could regulate lipid metabolism of NAFL in vivo and in vitro. PMID:27069915

  4. Lipid composition in a strain of Bacillus subtilis, a producer of iturin A lipopeptides that are active against uropathogenic bacteria.

    PubMed

    Bernat, Przemysław; Paraszkiewicz, Katarzyna; Siewiera, Paulina; Moryl, Magdalena; Płaza, Grażyna; Chojniak, Joanna

    2016-10-01

    Urinary tract infections are a common disease in humans. Therefore, new methods are needed to destroy biofilms that are formed by uropathogens. Iturin A lipopeptides (LPs) C14 and C15 are potent biosurfactants synthetized by the Bacillus subtilis I'1a strain. The biological activity of extracted LPs was confirmed by examining extracts from I'1a cultures against uropathogenic bacteria that had been isolated from biofilms on urinary catheters. Compared with cultures of DSM 3257, which produce surfactin at a relatively low level, the extract obtained from strain I'1a exhibited a greater inhibitory effect against both planktonic and sessile forms of Escherichia coli, Serratia marcescens, Enterobacter cloacae, Proteus mirabilis, Citrobacter freundii and Enterococcus faecalis. Moreover, cyclic LP biosurfactants may disturb the integrity of cytoplasmic membranes; therefore, we investigated the effects of synthetized LPs on fatty acids and phospholipids of B. subtilis. LPs and lipids were analyzed using GC-MS, LC-MS/MS and MALDI-TOF/TOF techniques. Compared with B. subtilis DSM 3257, membranes of the I'1a strain were characterized by an increased amount of anteiso fatty acids and a ten-fold higher ratio of phosphatidylglycerol (PG)-to-phosphatidylethanolamine (PE). Interestingly, in cultures of B. subtilis DSM 3257 supplemented with LP extracts of the I'1a strain, the PG-to-PE ratio was fourfold higher, and the amount of anteiso fatty acids was also increased.

  5. Property of large conductance Ca(2+)-activated K+ channels from Fasciola hepatica incorporated into planar lipid bilayer.

    PubMed

    Jang, Jung Hee; Park, Jin Bong; Kim, Sun Don; Lee, So Yeong; Hong, Sung-Jong; Ryu, Pan Dong

    2012-05-25

    Fasciola hepatica causes biliary epithelial hyperplasia and obstructive jaundice in humans and animals. Using a planar lipid bilayer technique, we further characterized the single channel property of large conductance K(+)-permeable channels that were previously identified from F. hepatica. The single channel conductance was 254.7±17.9 pS under a symmetrical 200/200 mM (cis/trans) KCl gradient. Open state probability (P(o)) varied from channel to channel at a given membrane potential and Ca(2+) concentration, but increased with voltage (-60 to +40 mV) and cis Ca(2+) (1-200 μM). Under a near bi-ionic condition of 200 mM [K(+)](cis)/200 mM [Na(+)](trans), the permeability ratio of K(+) to Na(+) was 5.0. Charybdotoxin (1 μM) inhibited P(o), whereas tetraethylammonium reduced the conductance (K(D)=67.8mM). Taken together, the results show that the single channel properties of the large conductance K(+)-permeable channels in F. hepatica are similar to those of large conductance Ca(2+)-activated K(+) (BK) channels in general, but distinct from typical BK channels in the extent of voltage- and Ca(2+)-dependence, as well as permeability to Na(+). This study further reveals a variant BK channel in F. hepatica that could serve as a new drug target to treat fascioliasis.

  6. Active and water-soluble form of lipidated Wnt protein is maintained by a serum glycoprotein afamin/α-albumin

    PubMed Central

    Mihara, Emiko; Hirai, Hidenori; Yamamoto, Hideki; Tamura-Kawakami, Keiko; Matano, Mami; Kikuchi, Akira; Sato, Toshiro; Takagi, Junichi

    2016-01-01

    Wnt plays important role during development and in various diseases. Because Wnts are lipidated and highly hydrophobic, they can only be purified in the presence of detergents, limiting their use in various in vitro and in vivo assays. We purified N-terminally tagged recombinant Wnt3a secreted from cells and accidentally discovered that Wnt3a co-purified with a glycoprotein afamin derived from the bovine serum included in the media. Wnt3a forms a 1:1 complex with afamin, which remains soluble in aqueous buffer after isolation, and can induce signaling in various cellular systems including the intestical stem cell growth assay. By co-expressing with afamin, biologically active afamin-Wnt complex can be easily obtained in large quantity. As afamin can also solubilize Wnt5a, Wnt3, and many more Wnt subtypes, afamin complexation will open a way to put various Wnt ligands and their signaling mechanisms under a thorough biochemical scrutiny that had been difficult for years. DOI: http://dx.doi.org/10.7554/eLife.11621.001 PMID:26902720

  7. Rifampicin-Induced Hepatic Lipid Accumulation: Association with Up-Regulation of Peroxisome Proliferator-Activated Receptor γ in Mouse Liver

    PubMed Central

    Zhang, Da-Gang; Li, Lu; Chen, Xi; Xu, De-Xiang

    2016-01-01

    Previous study found that rifampicin caused intrahepatic cholestasis. This study investigated the effects of rifampicin on hepatic lipid metabolism. Mice were orally administered with rifampicin (200 mg/kg) daily for different periods. Results showed that serum TG level was progressively reduced after a short elevation. By contrast, hepatic TG content was markedly increased in rifampicin-treated mice. An obvious hepatic lipid accumulation, as determined by Oil Red O staining, was observed in mice treated with rifampicin for more than one week. Moreover, mRNA levels of Fas, Acc and Scd-1, several key genes for fatty acid synthesis, were elevated in rifampicin-treated mice. In addition, the class B scavenger receptor CD36 was progressively up-regulated by rifampicin. Interestingly, hepatic SREBP-1c and LXR-α, two important transcription factors that regulate genes for hepatic fatty acid synthesis, were not activated by rifampicin. Instead, hepatic PXR was rapidly activated in rifampicin-treated mice. Hepatic PPARγ, a downstream target of PXR, was transcriptionally up-regulated. Taken together, the increased hepatic lipid synthesis and uptake of fatty acids from circulation into liver jointly contribute to rifampicin-induced hepatic lipid accumulation. The increased uptake of fatty acids from circulation into liver might be partially attributed to rifampicin-induced up-regulation of PPARγ and its target genes. PMID:27806127

  8. Degradable lipid nanoparticles with predictable in vivo siRNA delivery activity

    NASA Astrophysics Data System (ADS)

    Whitehead, Kathryn A.; Dorkin, J. Robert; Vegas, Arturo J.; Chang, Philip H.; Veiseh, Omid; Matthews, Jonathan; Fenton, Owen S.; Zhang, Yunlong; Olejnik, Karsten T.; Yesilyurt, Volkan; Chen, Delai; Barros, Scott; Klebanov, Boris; Novobrantseva, Tatiana; Langer, Robert; Anderson, Daniel G.

    2014-06-01

    One of the most significant challenges in the development of clinically viable delivery systems for RNA interference therapeutics is to understand how molecular structures influence delivery efficacy. Here, we have synthesized 1,400 degradable lipidoids and evaluate their transfection ability and structure-function activity. We show that lipidoid nanoparticles mediate potent gene knockdown in hepatocytes and immune cell populations on IV administration to mice (siRNA EC50 values as low as 0.01 mg kg-1). We identify four necessary and sufficient structural and pKa criteria that robustly predict the ability of nanoparticles to mediate greater than 95% protein silencing in vivo. Because these efficacy criteria can be dictated through chemical design, this discovery could eliminate our dependence on time-consuming and expensive cell culture assays and animal testing. Herein, we identify promising degradable lipidoids and describe new design criteria that reliably predict in vivo siRNA delivery efficacy without any prior biological testing.

  9. Adiponectin increases glucose-induced insulin secretion through the activation of lipid oxidation.

    PubMed

    Patané, G; Caporarello, N; Marchetti, P; Parrino, C; Sudano, D; Marselli, L; Vigneri, R; Frittitta, L

    2013-12-01

    The expression of adiponectin receptors has been demonstrated in human and rat pancreatic beta cells, where globular (g) adiponectin rescues rat beta cells from cytokine and fatty acid-induced apoptosis. The aim of our study was to evaluate whether adiponectin has a direct effect on insulin secretion and the metabolic pathways involved. Purified human pancreatic islets and rat beta cells (INS-1E) were exposed (1 h) to g-adiponectin, and glucose-induced insulin secretion was measured. A significant increase in glucose-induced insulin secretion was observed in the presence of g-adiponectin (1 nmol/l) with respect to control cells in both human pancreatic islets (n = 5, p < 0.05) and INS-1E cells (n = 5, p < 0.001). The effect of globular adiponectin on insulin secretion was independent of AMP-dependent protein kinase (AMPK) activation or glucose oxidation. In contrast, g-adiponectin significantly increased oleate oxidation (n = 5, p < 0.05), and the effect of g-adiponectin (p < 0.001) on insulin secretion by INS-1E was significantly reduced in the presence of etomoxir (1 μmol/l), an inhibitor of fatty acid beta oxidation. g-Adiponectin potentiates glucose-induced insulin secretion in both human pancreatic islets and rat beta cells via an AMPK independent pathway. Increased fatty acid oxidation rather than augmented glucose oxidation is the mechanism responsible. Overall, our data indicate that, in addition to its anti-apoptotic action, g-adiponectin has another direct effect on beta cells by potentiating insulin secretion. Adiponectin, therefore, in addition to its well-known effect on insulin sensitivity, has important effects at the pancreatic level.

  10. [Analysis of the applicability of model systems to measuring the activity of lipid-soluble antioxidants by the electrochemiluminescent method].

    PubMed

    Lukin, Iu L

    1976-11-01

    A comparative study of two most common model systems (methanol-sodium citrate and chloroform-aceton-maleic acid (10(-3) M)) was carried out to measure lipid-soluble antioxidants by the method of electrochemiluminescence. alpha-naftole, pyrogalole, phenole, hydroquinone, acrylamide, cholesterine and alkohol lipid extract from rat liver were used as inhibitors. The analysis has shown that it is worthwhile to apply only the system chloroform-aceton-maleic acid as a model of electroluminescent studies.

  11. Gemfibrozil, a Lipid-lowering Drug, Increases Myelin Genes in Human Oligodendrocytes via Peroxisome Proliferator-activated Receptor-β*

    PubMed Central

    Jana, Malabendu; Mondal, Susanta; Gonzalez, Frank J.; Pahan, Kalipada

    2012-01-01

    An increase in CNS remyelination and a decrease in CNS inflammation are important steps to halt the progression of multiple sclerosis. Earlier studies have shown that gemfibrozil, a lipid-lowering drug, has anti-inflammatory properties. The current study identified another novel property of gemfibrozil in stimulating the expression of myelin-specific genes (myelin basic protein, myelin oligodendrocyte glycoprotein, 2′,3′-cyclic-nucleotide 3′-phosphodiesterase, and proteolipid protein (PLP)) in primary human oligodendrocytes, mixed glial cells, and spinal cord organotypic cultures. Although gemfibrozil is a known activator of peroxisome proliferator-activated receptor-α (PPAR-α), we were unable to detect PPAR-α in either gemfibrozil-treated or untreated human oligodendrocytes, and gemfibrozil increased the expression of myelin genes in oligodendrocytes isolated from both wild type and PPAR-α(−/−) mice. On the other hand, gemfibrozil markedly increased the expression of PPAR-β but not PPAR-γ. Consistently, antisense knockdown of PPAR-β, but not PPAR-γ, abrogated the stimulatory effect of gemfibrozil on myelin genes in human oligodendrocytes. Gemfibrozil also did not up-regulate myelin genes in oligodendroglia isolated from PPAR-β(−/−) mice. Chromatin immunoprecipitation analysis showed that gemfibrozil induced the recruitment of PPAR-β to the promoter of PLP and myelin oligodendrocyte glycoprotein genes in human oligodendrocytes. Furthermore, gemfibrozil treatment also led to the recruitment of PPAR-β to the PLP promoter in vivo in the spinal cord of experimental autoimmune encephalomyelitis mice and suppression of experimental autoimmune encephalomyelitis symptoms in PLP-T cell receptor transgenic mice. These results suggest that gemfibrozil stimulates the expression of myelin genes via PPAR-β and that gemfibrozil, a prescribed drug for humans, may find further therapeutic use in demyelinating diseases. PMID:22879602

  12. Lipid-Mediated Endocytosis

    PubMed Central

    Ewers, Helge; Helenius, Ari

    2011-01-01

    Receptor-mediated endocytosis is used by a number of viruses and toxins to gain entry into cells. Some have evolved to use specific lipids in the plasma membrane as their receptors. They include bacterial toxins such as Shiga and Cholera toxin and viruses such as mouse polyoma virus and simian virus 40. Through multivalent binding to glycosphingolipids, they induce lipid clustering and changes in membrane properties. Internalization occurs by unusual endocytic mechanisms involving lipid rafts, induction of membrane curvature, trans-bilayer coupling, and activation of signaling pathways. Once delivered to early endosomes, they follow diverse intracellular routes to the lumen of the ER, from which they penetrate into the cytosol. The role of the lipid receptors is central in these well-studied processes. PMID:21576253

  13. Activation of hindbrain neurons in response to gastrointestinal lipid is attenuated by high fat, high energy diets in mice prone to diet-induced obesity.

    PubMed

    Donovan, Michael J; Paulino, Gabriel; Raybould, Helen E

    2009-01-12

    Food intake is controlled by peripheral signals from the gastrointestinal tract and adipocytes, which are integrated within the central nervous system. There is evidence that signals from the GI tract are modulated by long term changes in diet, possibly leading to hyperphagia and increased body weight. We tested the hypothesis that diet-induced obese-prone (DIO-P) and obese-resistant (DIO-R) mice strains differ in the long term adaptive response of the gut-brain pathway to a high fat diet. Immunochemical detection of Fos protein was used as a measure of neuronal activation in the nucleus of the solitary tract (NTS) in response to intragastric administration of lipid in DIO-P (C57Bl6) and DIO-R (129sv) mouse strains maintained on chow or high fat, high energy diets (45% or 60% kcal from fat). Intragastric lipid administration activated neurons in the NTS in both DIO-P and DIO-R mice; the number of activated neurons was significantly greater in DIO-P than in DIO-R mice (P<0.001). However, lipid-induced activation of NTS neurons in DIO-P mice was attenuated by approximately 30% after maintenance on either 45% or 60% HF diet, for 4 or 8 weeks, compared to chow fed controls (P<0.05). In contrast, in DIO-R mice, maintenance on a HF diet (45% or 60%) had no effect on lipid-induced activation of NTS neurons. These results demonstrate that DIO-P and DIO-R mice strains differ in the adaptation of the pathway to long term ingestion of high fat diets, which may contribute to decrease satiation and increased food intake.

  14. Lipid nanocapsules containing the non-ionic surfactant Solutol HS15 inhibit the transport of calcium through hyperforin-activated channels in neuronal cells.

    PubMed

    Chauvet, Sylvain; Barras, Alexandre; Boukherroub, Rabah; Bouron, Alexandre

    2015-12-01

    Hyperforin is described as a natural antidepressant inhibiting the reuptake of neurotransmitters and also activating cation channels. However the blood-brain barrier limits the access to the brain of this biomolecule. To circumvent this problem it was envisaged to encapsulate hyperforin into biomimetic lipid nano-carriers like lipid nanocapsules (LNCs). When testing the safety of 25 nm LNCs it appeared that they strongly blocked hyperforin-activated Ca2+ channels of cultured cortical neurons. This inhibition was due to one of their main component: solutol HS15 (polyoxyethylene-660-12-hydroxy stearate), a non-ionic soluble surfactant. Solutol HS15 rapidly depresses in a concentration-dependent manner the entry of Ca2+ through hyperforin-activated channels without influencing store-operated channels. This effect is mimicked by Brij58 but not by PEG600, indicating that the lipid chain of Solutol HS15 is important in determining its effects on the channels. The inhibition of the Ca2+ fluxes depends on the cellular cholesterol content; it is stronger after depleting cholesterol with methyl-β-cyclodextrin and is nearly absent on cells cultured in a cholesterol-rich medium. When chronically applied for 24 h, Solutol HS15 slightly up-regulates the entry of Ca2+ through hyperforin-activated channels. Similar observations were made when testing 25 nm lipid nanocapsules containing the surfactant Solutol HS15. Altogether, this study shows that Solutol HS15 perturbs in a cholesterol-dependent manner the activity of some neuronal channels. This is the first demonstration that LNCs containing this surfactant can influence cellular calcium signaling in the brain, a finding that can have important clinical implications.

  15. Minocycline increases the life span and motor activity and decreases lipid peroxidation in manganese treated Drosophila melanogaster.

    PubMed

    Bonilla, E; Contreras, R; Medina-Leendertz, S; Mora, M; Villalobos, V; Bravo, Y

    2012-03-29

    The objective of this study was to investigate the effect of Minocycline in the life span, motor activity, and lipid peroxidation of Drosophila melanogaster treated with manganese. Two days after emerging from the pupa male wild-type D. melanogaster were fed for 13 days with corn media containing 15 mM manganese. Then, they were divided in six groups of 300 flies each: group (a) remained treated with manganese (Mn group); group (b) began treatment with Minocycline (0.05 mM) (Mn-Minocycline group); group (c) received no additional treatment (Mn-no treatment group); group (d) simultaneously fed with manganese and Minocycline (Mn+Minocycline group). Additionally, a control (group e) with no treatment and another group (f) fed only with Minocycline after emerging from the pupa were added. All the manganese treated flies (group a) were dead on the 25th day. The life span in group f (101.66±1.33 days, mean S.E.M.) and of group b (97.00±3.46 days) were similar, but in both cases it was significantly higher than in group e (68.33±1.76 days), group c (67.05±2.30 days) and in those of group d (37.33±0.88). Manganese (groups a and d) decreased motor activity in D. melanogaster. In the Minocycline fed flies (groups b and f) a higher motor activity was detected. In Mn-Minocycline and Mn+Minocycline treated flies a significant decrease of MDA levels was detected when compared to the Minocycline group indicating that Minocycline and Mn appear to have a synergistic effect. In conclusion, Minocycline increased the life span and motor activity and decreased MDA formation of manganese treated D. melanogaster, probably by an inhibition of the production of reactive oxygen species. Manganese also exerted an antioxidant effect as shown by the significant decrease of MDA levels when compared to control flies.

  16. Selective interaction of LAT (linker of activated T cells) with the open-active form of Lck in lipid rafts reveals a new mechanism for the regulation of Lck in T cells.

    PubMed Central

    Kabouridis, Panagiotis S

    2003-01-01

    In T cells, the lipid raft-associated Lck is strongly tyrosine phosphorylated and has reduced enzymic activity in contrast with the detergent-soluble pool, which has substantial activity. Lck tagged at the C-terminus (Lck/V5-His) was efficiently captured by epitope-specific reagents from the detergent-soluble fraction but not from lipid rafts. Binding was restored following urea denaturation, suggesting that Lck/V5-His is in a 'closed' conformation in these domains. In agreement with this hypothesis, the Tyr(505) --> Phe/V5-His and Arg(154) --> Lys/V5-His mutants, which disrupt the SH2-Tyr(505) intramolecular interaction, were efficiently precipitated from lipid rafts. In contrast to Lck, Fyn/V5-His was precipitated equally well from both fractions. In the LAT(linker of activated T cells)-deficient J.CaM2 cells, Tyr(505) phosphorylation of raft-associated Lck was reduced whereas its enzymic activity was elevated. This correlated with decreased levels of raft-localized Csk (C-terminal Src kinase) kinase. Increased tyrosine phosphorylation of Lck was restored in LAT-reconstituted J.CaM2 cells suggesting that LAT negatively regulates Lck activity in lipid rafts. Co-immunoprecipitation experiments from Tyr(505) --> Phe/V5-His-expressing cells revealed that LAT preferentially interacts with the 'open' form of Lck in T cell raft domains. These results demonstrate that, unlike the non-raft pool, Lck in lipid rafts has a 'closed'-inactive structure, and that LAT plays a role in maintaining this conformation, possibly by facilitating critical associations within lipid rafts via its capacity to interact with the 'open' form of the kinase. PMID:12570875

  17. IRE1α-XBP1s induces PDI expression to increase MTP activity for hepatic VLDL assembly and lipid homeostasis.

    PubMed

    Wang, Shiyu; Chen, Zhouji; Lam, Vivian; Han, Jaeseok; Hassler, Justin; Finck, Brian N; Davidson, Nicholas O; Kaufman, Randal J

    2012-10-03

    The unfolded protein response (UPR) is a signaling pathway required to maintain endoplasmic reticulum (ER) homeostasis and hepatic lipid metabolism. Here, we identify an essential role for the inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α)-X box binding protein 1 (XBP1) arm of the UPR in regulation of hepatic very low-density lipoprotein (VLDL) assembly and secretion. Hepatocyte-specific deletion of Ire1α reduces lipid partitioning into the ER lumen and impairs the assembly of triglyceride (TG)-rich VLDL but does not affect TG synthesis, de novo lipogenesis, or the synthesis or secretion of apolipoprotein B (apoB). The defect in VLDL assembly is, at least in part, due to decreased microsomal triglyceride-transfer protein (MTP) activity resulting from reduced protein disulfide isomerase (PDI) expression. Collectively, our findings reveal a key role for the IRE1α-XBP1s-PDI axis in linking ER homeostasis with regulation of VLDL production and hepatic lipid homeostasis that may provide a therapeutic target for disorders of lipid metabolism.

  18. Characterization of the Aroma-Active, Phenolic, and Lipid Profiles of the Pistachio (Pistacia vera L.) Nut as Affected by the Single and Double Roasting Process.

    PubMed

    Rodríguez-Bencomo, Juan José; Kelebek, Hasim; Sonmezdag, Ahmet Salih; Rodríguez-Alcalá, Luis Miguel; Fontecha, Javier; Selli, Serkan

    2015-09-09

    The pistachio (Pistacia vera L.) nut is one of the most widely consumed edible nuts in the world. However, it is the roasting process that makes the pistachio commercially viable and valuable as it serves as the key step to improving the nut's hallmark sensory characteristics including flavor, color, and texture. Consequently, the present study explores the effects of the single-roasting and double-roasting process on the pistachio's chemical composition, specifically aroma-active compounds, polyphenols, and lipids. Results showed the total polyphenol content of increased with the roasting treatment; however, not all phenolic compounds demonstrated this behavior. With regard to the aroma and aroma-active compounds, the results indicated that roasting process results in the development of characteristics and pleasant aroma of pistachio samples due to the Maillard reaction. With regard to lipids, the pistachio roasting treatment reduced the concentration of CN38 diacylglycerides while increasing the amount of elaidic acid.

  19. Tlr4-mutant mice are resistant to acute alcohol-induced sterol-regulatory element binding protein activation and hepatic lipid accumulation.

    PubMed

    Zhang, Zhi-Hui; Liu, Xiao-Qian; Zhang, Cheng; He, Wei; Wang, Hua; Chen, Yuan-Hua; Liu, Xiao-Jing; Chen, Xi; Xu, De-Xiang

    2016-09-15

    Previous studies demonstrated that acute alcohol intoxication caused hepatic lipid accumulation. The present study showed that acute alcohol intoxication caused hepatic lipid accumulation in Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic sterol-regulatory element binding protein (SREBP)-1, a transcription factor regulating fatty acid and triglyceride (TG) synthesis, was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic Fas, Acc, Scd-1 and Dgat-2, the key genes for fatty acid and TG synthesis, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Additional experiment showed that hepatic MyD88 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic NF-κB was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Moreover, hepatic GSH content was reduced and hepatic MDA level was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic CYP2E1 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic p67phox and gp91phox, two NADPH oxidase subunits, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin-trapping agent, protected against alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. In conclusion, Tlr4-mutant mice are resistant to acute alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation.

  20. Tlr4-mutant mice are resistant to acute alcohol-induced sterol-regulatory element binding protein activation and hepatic lipid accumulation

    PubMed Central

    Zhang, Zhi-Hui; Liu, Xiao-Qian; Zhang, Cheng; He, Wei; Wang, Hua; Chen, Yuan-Hua; Liu, Xiao-Jing; Chen, Xi; Xu, De-Xiang

    2016-01-01

    Previous studies demonstrated that acute alcohol intoxication caused hepatic lipid accumulation. The present study showed that acute alcohol intoxication caused hepatic lipid accumulation in Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic sterol-regulatory element binding protein (SREBP)-1, a transcription factor regulating fatty acid and triglyceride (TG) synthesis, was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic Fas, Acc, Scd-1 and Dgat-2, the key genes for fatty acid and TG synthesis, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Additional experiment showed that hepatic MyD88 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic NF-κB was activated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Moreover, hepatic GSH content was reduced and hepatic MDA level was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic CYP2E1 was elevated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Hepatic p67phox and gp91phox, two NADPH oxidase subunits, were up-regulated in alcohol-treated Tlr4-wild-type mice but not in Tlr4-mutant mice. Alpha-phenyl-N-t-butylnitrone (PBN), a free radical spin-trapping agent, protected against alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. In conclusion, Tlr4-mutant mice are resistant to acute alcohol-induced hepatic SREBP-1 activation and hepatic lipid accumulation. PMID:27627966

  1. Solid lipid nanoparticles affect microbial colonization and enzymatic activity throughout the decomposition of alder leaves in freshwater microcosms.

    PubMed

    Sampaio, A C; Mendes, R J; Castro, P G; Silva, A M

    2017-01-01

    Solid lipid nanoparticles (SLNs) are used as carriers for drug delivery, and are high biocompatible and designed to endure in the host organism. Despite its current industrial production is low, many of these substances are available on the market, and much more are in the production pipeline. As a result, many of them will end in aquatic systems raising the question whether they can pose a risk to aquatic biota and the associated ecological processes. Microbial decomposers of plant litter, play a key role in forested streams being responsible for the energy flow between terrestrial and aquatic environments. Here, we investigated the effects of SLNs on alder leaf litter decomposition by aquatic microbes. Alder leaves were immersed in a stream of Northeast Portugal to allow microbial colonization before being exposed in microcosms of two types of SLNs at two concentrations for 42 days. Results showed that rates of leaf decomposition decreased with exposure to SLNs. Bacterial biomass was not inhibited by SLNs, and cultivable fungi densities remained constant (SLN-A) or increased (SLN-C) compared with control microcosms. The type and concentration of SLNs influenced differently the leaf colonization by fungi as well as fungal sporulation rate. These effects were accompanied by changes in the community extraenzymatic profile: the activities of alkaline phosphatase, acidic phosphatase, Naphthol-AS-BI-phosphohydrolase (P cycle) and lipases increased in the SLNs microcosms. This study provided the first evidence of the adverse effects of the release of SLNs to streams on leaf litter decomposition. Those effects seem to depend on the composition and concentration of SLNs, as well on the microbial target group, or enzyme. Thus, prior to massive industrial production of these nanomaterials, some measures should be taken to avoid environmental impact affecting the microbial communities responsible for detritus decomposition.

  2. Lipid droplet binding thalidomide analogs activate endoplasmic reticulum stress and suppress hepatocellular carcinoma in a chemically induced transgenic mouse model

    PubMed Central

    2013-01-01

    Background Hepatocellular carcinoma (HCC) is the most frequent and aggressive primary tumor of the liver and it has limited treatment options. Results In this study, we report the in vitro and in vivo effects of two novel amino-trifluoro-phtalimide analogs, Ac-915 and Ac-2010. Both compounds bind lipid droplets and endoplasmic reticulum membrane, and interact with several proteins with chaperone functions (HSP60, HSP70, HSP90, and protein disulfide isomerase) as determined by affinity chromatography and resonant waveguide optical biosensor technology. Both compounds inhibited protein disulfide isomerase activity and induced cell death of different HCC cells at sub or low micromolar ranges detected by classical biochemical end-point assay as well as with real-time label-free measurements. Besides cell proliferation inhibiton, analogs also inhibited cell migration even at 250 nM. Relative biodistribution of the analogs was analysed in native tissue sections of different organs after administration of drugs, and by using fluorescent confocal microscopy based on the inherent blue fluorescence of the compounds. The analogs mainly accumulated in the liver. The effects of Ac-915 and Ac-2010 were also demonstrated on the advanced stages of hepatocarcinogenesis in a transgenic mouse model of N-nitrosodiethylamine (DEN)-induced HCC. Significantly less tumor development was found in the livers of the Ac-915- or Ac-2010-treated groups compared with control mice, characterized by less liver tumor incidence, fewer tumors and smaller tumor size. Conclusion These results imply that these amino-trifluoro-phthalimide analogs could serve potent clinical candidates against HCC alone or in combination with dietary polyunsaturated fatty acids. PMID:24268070

  3. Plasma phospholipid mass transfer rate: relationship to plasma phospholipid and cholesteryl ester transfer activities and lipid parameters.

    PubMed

    Cheung, M C; Wolfbauer, G; Albers, J J

    1996-09-27

    Human plasma phospholipid transfer protein (PLTP) has been shown to facilitate the transfer of phospholipid from liposomes or isolated very low and low density lipoproteins to high density lipoproteins. Its activity in plasma and its physiological function are presently unknown. To elucidate the role of PLTP in lipoprotein metabolism and to delineate factors that may affect the rate of phospholipid transfer between lipoproteins, we determined the plasma phospholipid mass transfer rate (PLTR) in 16 healthy adult volunteers and assessed its relationship to plasma lipid levels, and to phospholipid transfer activity (PLTA) and cholesteryl ester transfer activity (CETA) measured by radioassays. The plasma PLTR in these subjects was 27.2 +/- 11.8 nmol/ml per h at 37 degrees C (mean +/- S.D.), and their PLTA and CETA were 13.0 +/- 1.7 mumol/ml per h and 72.8 +/- 15.7 nmol/ml per h, respectively. Plasma PLTR was correlated directly with total, non-HDL, and HDL triglyceride (rs = 0.76, P < 0.001), total and non-HDL phospholipid (rs > 0.53, P < 0.05), and inversely with HDL free cholesterol (rs = -0.54, P < 0.05), but not with plasma PLTA and CETA. When 85% to 96% of the PLTA in plasma was removed by polyclonal antibodies against recombinant human PLTP, phospholipid mass transfer from VLDL and LDL to HDL was reduced by 50% to 72%, but 80% to 100% of CETA could still be detected. These studies demonstrate that PLTP plays a major role in facilitating the transfer of phospholipid between lipoproteins, and suggest that triglyceride is a significant modulator of intravascular phospholipid transport. Furthermore, most of the PLTP and CETP in human plasma is associated with different particles. Plasma PLTA and CETA were also measured in mouse, rat, hamster, guinea pig, rabbit, dog, pig, and monkey. Compared to human, PLTA in rat and mouse was significantly higher and in rabbit and guinea pig was significantly lower while the remaining animal species had PLTA similar to humans. No

  4. Effects of hydrostatic pressure on lipid bilayer membranes. II. Activation and reaction volumes of carrier mediated ion transport.

    PubMed Central

    Benz, R.; Conti, F.

    1986-01-01

    Measurements of voltage relaxations following brief charge-pulses applied to lipid bilayers have been performed at different hydrostatic pressures in the presence of the neutral carriers cyclo (D-Val-L-Pro-L-Val-D-Pro)3(PV) and valinomycin. From double-exponential relaxations observed in membranes containing PV-K+ complexes estimates were obtained of the amount of membrane absorbed complexes, NMS, and of the rate of complex translocation, kMS. The pressure dependence of kMS corresponded to an activation volume for translocation of approximately 12 cm3/mol independent of ionic strength and K+ concentration. The pressure dependence of NMS strongly varied with K+-concentration suggesting a major role of ion-complexation in solution which is estimated to involve a reaction volume of 25.5 cm3/mol, while the volume of absorption of a PV-K+ complex by the membrane was estimated -7.5 cm3/mol. The relaxations observed in the presence of valinomycin contained three exponentials and could be used to estimate four rate constants and one absorption parameter which characterize the valinomycin-mediated transport. When the transport of Rb+ was tested, the rate constant for the complex dissociation, kD, and the total concentration of free and complexed carriers in the membrane, No, were found to be pressure insensitive. The translocation rates for the complex, kMS and for the free carrier, kS, were instead markedly pressure dependent according to estimated activation volumes in the range of 11 to 18 cm3/mol. The recombination rate constant kR was also pressure dependent according to an activation volume of 12-14 cm3/mol. The study of the valinomycin-K+ transport yielded similar results as far as N.,ks, and kms are concerned, but in this case kR was pressure independent, while kD was increased by pressure. The net volume change associated with the transfer of a free ion to the membrane in the form of a valinomycin-ion complex was nevertheless very similar for K+ and Rb+. It is

  5. Solid lipid nanoparticles containing copaiba oil and allantoin: development and role of nanoencapsulation on the antifungal activity.

    PubMed

    Svetlichny, G; Külkamp-Guerreiro, I C; Cunha, S L; Silva, F E K; Bueno, K; Pohlmann, A R; Fuentefria, A M; Guterres, S S

    2015-03-01

    The aim of this work was to develop solid lipid nanoparticles (SLN) containing copaiba oil with and without allantoin (NCOA, NCO, respectively) and to evaluate their antifungal activity. Nanoparticle suspensions were prepared using a high homogenisation technique and characterised by dynamic light scattering, laser diffraction, nanoparticle tracking analysis, multiple light scattering analysis, high-pressure liquid chromatography, pH and rheology. The antifungal activities of the formulations were tested in vitro against the emergent yeasts Candida krusei and Candida parapsilosis, and the fungal pathogens of human skin Trichophyton rubrum and Microsporum canis. The dynamic light scattering analysis showed z-average diameters (intensity) between 118.63 ± 8.89 nm for the nanoparticles with both copaiba oil and allantoin and 126.06 ± 9.84nm for the nanoparticles with just copaiba oil. The D[4,3] determined by laser diffraction showed similar results of 123 ± 1.73 nm for the nanoparticles with copaiba oil and allantoin and 130 ± 3.6 nm for the nanoparticles with copaiba oil alone. Nanoparticle tracking analysis demonstrated that both suspensions had monomodal profiles and consequently, the nanoparticle populations were homogeneous. This analysis also corroborated the results of dynamic light scattering and laser diffraction, exhibiting a smaller mean diameter for the nanoparticles with copaiba oil and allantoin (143 nm) than for the nanoparticles with copaiba oil (204 nm). The physicochemical properties indicated that the dispersions were stable overtime. Rheology evidenced Newtonian behaviour for both suspensions. Antifungal susceptibility showed a MIC90 of 125 μg/mL (nanoparticles with copaiba oil) and 7.8 μg/mL (nanoparticles with copaiba oil and allantoin) against C. parapsilosis. The nanoparticles with copaiba oil and the nanoparticles with copaiba oil and allantoin presented a MIC90 of 500 μg/mL and 250 μg/mL, respectively, against C. krusei. The MIC90

  6. Enhancement of skin radical scavenging activity