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BBA - Molecular and Cell Biology of Lipids (v.1831, #4)

Editorial Board (pp. i).

Disruption of the MIG1 gene enhances lipid biosynthesis in the oleaginous yeast Yarrowia lipolytica ACA-DC 50109 by Zhi-Peng Wang; Hong-Mei Xu; Guang-Yuan Wang; Zhe Chi; Zhen-Ming Chi (pp. 675-682).

In this study, the MIG1 gene in the oleaginous yeast Yarrowia lipolytica ACA-DC 50109 (the parent yeast) was disrupted and the disruptant M25 obtained could grow in yeast nitrogen base-N₅₀₀₀ medium without uracil or the medium with 2-deoxy-D-glucose. It was found that the cells of the disruptant M25 had more lipid bodies than those of its parent yeast. The disruptant M25 contained 48.7% (w/w) of oil based on its cell weight while the parent yeast only contained 36.0% (w/w) of oil. Transcript levels of many genes relevant to lipid biosynthesis in the disruptant M25 were enhanced compared to those of the same genes in the parent yeast. However, transcript level of the MFE1 gene, one of the genes relevant to fatty acid degradation was reduced in the disruptant M25 compared to that of the same gene in the parent yeast. Such changes in gene expression profile may cause the increased lipid biosynthesis in the disruptant M25. Biosynthesis of C_18:1 fatty acid in the disruptant M25 was greatly enhanced compared to that in the parent yeast.► The cells of the disruptant M25 had more lipid bodies than its parent. ► The disruptant M25 contained 48.7% (w/w) of oil while its parent only contained 36.0% (w/w) of oil. ► Expression of many genes relevant to lipid biosynthesis in the disruptant M25 was enhanced.

Keywords: The oleaginous yeast; Yarrowia lipolytica; Lipid body; Oil accumulation; Gene expression

ATPase activity of nucleotide binding domains of human MDR3 in the context of MDR1 by Masato Ishigami; Yuko Tominaga; Kohjiro Nagao; Yasuhisa Kimura; Michinori Matsuo; Noriyuki Kioka; Kazumitsu Ueda (pp. 683-690).

Although human MDR1 and MDR3 share 86% similarity in their amino acid sequences and are predicted to share conserved domains for drug recognition, their physiological transport substrates are quite different: MDR1 transports xenobiotics and confers multidrug resistance, while MDR3 exports phosphatidylcholine into bile. Although MDR1 shows high ATPase activity, attempts to demonstrate the ATPase activity of human MDR3 have not succeeded. Therefore, it is possible that the difference in the functions of these proteins is caused by their different ATPase activities. To test this hypothesis, a chimera protein containing the transmembrane domains (TMDs) of MDR1 and the nucleotide binding domains (NBDs) of MDR3 was constructed and analyzed. The chimera protein was expressed on the plasma membrane and conferred resistance against vinblastine and paclitaxel, indicating that MDR3 NBDs can support drug transport. Vanadate-induced ADP trapping of MDR3 NBDs in the chimera protein was stimulated by verapamil as was MDR1 NBDs. The purified chimera protein showed drug-stimulated ATPase activity like MDR1, while its V_max was more than 10-times lower than MDR1. These results demonstrate that the low ATPase activity of human MDR3 cannot account for the difference in the functions of these proteins, and furthermore, that TMDs determine the features of NBDs. To our knowledge, this is the first study analyzing the features of human MDR3 NBDs.MDR3 NBD, which hydrolyzes ATP more than 10-times slower than MDR1 NBD, can support drug transport by MDR1 TMD.Display Omitted► MDR1 and MDR3 transport different substrates, xenobiotic and phosphatidylcholine, respectively. ► MDR3 NBDs hydrolyze ATP more than 10-times slower than MDR1 NBDs. ► ATPase activity cannot account for the difference in the functions of MDR1 and MDR3.

Keywords: Abbreviations; ABC; ATP-binding cassette; BSA; bovine serum albumin; DDM; n-dodecyl-β-; d; -maltopyranoside; DMEM; Dulbecco's modified Eagle's medium; DMSO; dimethyl sulfoxide; FBS; fetal bovine serum; HBSS; Hank's balanced salt solution; HEK; human embryonic kidney; HRP; horse radish peroxidase; MDR; multidrug resistance; NaTC; sodium taurocholate; NBD; nucleotide binding domain; PBS; phosphate-buffered saline; PC; phosphatidylcholine; SDS; sodium dodecyl sulfate; TMD; transmembrane domainABC protein; MDR3; MDR1; Phosphatidylcholine: ATPase; Transporter

Hepatic lipase- and endothelial lipase-deficiency in mice promotes macrophage-to-feces RCT and HDL antioxidant properties by Escola-Gil Joan Carles Escolà-Gil; Xiangyu Chen; Josep Julve; Helena Quesada; David Santos; Jari Metso; Monica Tous; Matti Jauhiainen; Francisco Blanco-Vaca (pp. 691-697).

Hepatic lipase (HL) and endothelial lipase (EL) are negative regulators of plasma HDL cholesterol (HDLc) levels and presumably could affect two main HDL atheroprotective functions, macrophage-to-feces reverse cholesterol transport (RCT) and HDL antioxidant properties. In this study, we assessed the effects of both HL and EL deficiency on macrophage-specific RCT process and HDL ability to protect against LDL oxidation. HL- and EL-deficient and wild-type mice were injected intraperitoneally with [³H]cholesterol-labeled mouse macrophages, after which the appearance of [³H]cholesterol in plasma, liver, and feces was determined. The degree of HDL oxidation and the protection of oxidative modification of LDL co-incubated with HDL were evaluated by measuring conjugated diene kinetics. Plasma levels of HDLc, HDL phospholipids, apoA-I, and platelet-activated factor acetyl-hydrolase were increased in both HL- and EL-deficient mice. These genetically modified mice displayed increased levels of radiolabeled, HDL-bound [³H]cholesterol 48h after the label injection. The magnitude of macrophage-derived [³H]cholesterol in feces was also increased in both the HL- and EL-deficient mice. HDL from the HL- and EL-deficient mice was less prone to oxidation and had a higher ability to protect LDL from oxidation, compared with the HDL derived from the wild-type mice. These changes were correlated with plasma apoA-I and apoA-I/HDL total protein levels. In conclusion, targeted inactivation of both HL and EL in mice promoted macrophage-to-feces RCT and enhanced HDL antioxidant properties.► Hepatic lipase (HL) and endothelial lipase (EL) deficiency promote RCT from macrophages to feces ► HDL from the HL- and EL-deficient mice is less prone to oxidation ► HDL from the HL- and EL-deficient mice has a higher ability to protect LDL from oxidation

Keywords: apoA-I; Endothelial lipase; Hepatic lipase; HDL; Oxidation; Reverse cholesterol transport

Cyanidin is an agonistic ligand for peroxisome proliferator-activated receptor-alpha reducing hepatic lipid by Yaoyao Jia; Jin-Young Kim; Hee-jin Jun; Sun-Joong Kim; Ji-Hae Lee; Minh Hien Hoang; Hyun Sook Kim; Hyo Ihl Chang; Kwang-Yeon Hwang; Soo-Jong Um; Sung-Joon Lee (pp. 698-708).

To investigate the underlying mechanism of targets of cyanidin, a flavonoid, which exhibits potent anti-atherogenic activities in vitro and in vivo, a natural chemical library that identified potent agonistic activity between cyanidin and peroxisome proliferator-activated receptors (PPAR) was performed. Cyanidin induced transactivation activity in all three PPAR subtypes in a reporter gene assay and time-resolved fluorescence energy transfer analyses. Cyanidin also bound directly to all three subtypes, as assessed by surface plasmon resonance experiments, and showed the greatest affinity to PPARα. These effects were confirmed by measuring the expression of unique genes of each PPAR subtype. Cyanidin significantly reduced cellular lipid concentrations in lipid-loaded steatotic hepatocytes. In addition, transcriptome profiling in lipid-loaded primary hepatocytes revealed that the net effects of stimulation with cyanidin on lipid metabolic pathways were similar to those elicited by hypolipidemic drugs. Cyanidin likely acts as a physiological PPARα agonist and potentially for PPARβ/δ and γ, and reduces hepatic lipid concentrations by rewiring the expression of genes involved in lipid metabolic pathways.Display Omitted► A flavonoid cyanidin functions as a PPARα agonist. ► Cyanidin significantly reduced cellular lipid in lipid-loaded steatotic hepatocytes. ► Cyanidin showed similar effects to hypolipidemic drugs on lipid metabolic pathways. ► Chemical structure of anthocyanidin could be used to develop moderate PPAR agonists.

Keywords: Abbreviations; PPAR; peroxisome proliferated-activated receptor; LBD; ligand-binding domain; RXR; retinoid X receptor; Apo; apolipoprotein; K; _D; equilibrium dissociation constant; EC; ₅₀; the half maximal effective concentration; SPR; surface plasmon resonance; TR-FRET; time-resolved fluorescent resonance energy transfer; PCA; procatechic acid; PGA; phloroglucinaldehydeCyanidin; Hepatocyte; Lipid metabolism; PPAR

Effect of conjugated linoleic acid, μ-calpain inhibitor, on pathogenesis of Alzheimer's disease by Eunyoung Lee; Ji-Eun Eom; Hye-Lin Kim; Kyung Hye Baek; Kyu-Yeon Jun; Hwa-Jung Kim; Minyung Lee; Inhee Mook-Jung; Youngjoo Kwon (pp. 709-718).

μ-Calpain is a calcium-dependent cysteine protease, which is activated by μM concentration of calcium in vitro. Disrupted intracellular calcium homeostasis leads to hyper-activation of μ-calpain. Hyper-activated μ-calpain enhances the accumulation of β-amyloid peptide by increasing the expression level of β-secretase (BACE1) and induces hyper-phosphorylation of tau along with the formation of neurofibrillary tangle by mediating p35 cleavage into p25, both of which are the major mechanisms of neurodegeneration in Alzheimer's disease (AD). Hence, inhibition of μ-calpain activity is very important in the treatment and prevention of AD. In this study, conjugated linoleic acid (CLA), an eighteen-carbon unsaturated fatty acid, was discovered as a μ-calpain-specific inhibitor. CLA showed neuroprotective effects against neurotoxins such as H₂O₂ and Aβ_1–42 in SH-SY5Y cells, and inhibited Aβ oligomerization/fibrillation and Aβ-induced Zona Occludens-1 degradation. In addition, CLA decreased the levels of proapoptotic proteins, p35 conversion to p25 and tau phosphorylation. These findings implicate CLA as a new core structure for selective μ-calpain inhibitors with neuroprotective effects. CLA should be further evaluated for its potential use as an AD therapeutic agent.► CLA is a potent, selective, and cell permeable non-peptidic μ-calpain inhibitor. ► CLA increased the viability of neurotoxin-treated SH-SY5Y cells. ► CLA directly scavenged ROS generation and prevented Aβ-induced ZO-1 degradation. ► CLA has a neuroprotective effect against H₂O₂ in cells and rat brain lysate. ► Docking studies showed that CLA fitted into the active site of μ-calpain.

Keywords: μ-Calpain inhibitor; Conjugated linoleic acid; Alzheimer's disease; Aβ; _1–42; oligomerization

Chronic pharmacological activation of P2Y₁₃ receptor in mice decreases HDL-cholesterol level by increasing hepatic HDL uptake and bile acid secretion by Nizar Serhan; Cendrine Cabou; Céline Verdier; Laeticia Lichtenstein; Nicole Malet; Bertrand Perret; Muriel Laffargue; Laurent O. Martinez (pp. 719-725).

High level of high-density lipoprotein cholesterol (HDL-cholesterol) is inversely correlated to the risk of atherosclerotic cardiovascular disease. The protective effect of HDL is mostly attributed to their metabolic functions in reverse cholesterol transport (RCT), a process whereby excess cell cholesterol is taken up from peripheral cells and processed in HDL particles, and is later delivered to the liver for further metabolism and bile excretion. We have previously demonstrated that P2Y₁₃ receptor is critical for RCT and that intravenous bolus injection of cangrelor (AR-C69931MX), a partial agonist of P2Y₁₃ receptor, can stimulate hepatic HDL uptake and subsequent lipid biliary secretion without any change in plasma lipid levels. In the present study, we investigated the effect of longer-term treatment with cangrelor on lipoprotein metabolism in mice. We observed that continuous delivery of cangrelor at a rate of 35μg/day/kg body weight for 3days markedly decreased plasma HDL-cholesterol level, by increasing the clearance of HDL particles by the liver. These effects were correlated to an increase in the rate of biliary bile acid secretion. An increased expression of SREBP-regulated genes of cholesterol metabolism was also observed without any change of hepatic lipid levels as compared to non-treated mice. Thus, 3-day cangrelor treatment markedly increases the flux of HDL-cholesterol from the plasma to the liver for bile acid secretion. Taken together our results suggest that P2Y₁₃ appears a promising target for therapeutic intervention aimed at preventing or reducing cardiovascular risk.► Pharmacological activation P2Y₁₃ receptor in vivo with cangrelor (AR-C69931MX) ► Cangrelor treatment stimulates plasma HDL clearance and HDL uptake by the liver. ► Cangrelor decreases HDL-C level while biliary bile acid secretion is increased. ► Role of P2Y₁₃ as a potential target in “HDL-Therapy” ► Role of P2Y₁₃ as a potential target in atherosclerosis

Keywords: High density lipoprotein (HDL); Purinergic receptor P2Y13; ATP synthase; Reverse cholesterol transport (RCT)

Iron, glucose and intrinsic factors alter sphingolipid composition as yeast cells enter stationary phase by Robert L. Lester; Bradley R. Withers; Megan A. Schultz; Robert C. Dickson (pp. 726-736).

Survival of Saccharomyces cerevisiae cells, like most microorganisms, requires switching from a rapidly dividing to a non-dividing or stationary state. To further understand how cells navigate this switch, we examined sphingolipids since they are key structural elements of membranes and also regulate signaling pathways vital for survival. During and after the switch to a non-dividing state there is a large increase in total free and sphingolipid-bound long chain-bases and an even larger increase in free and bound C20-long-chain bases, which are nearly undetectable in dividing cells. These changes are due to intrinsic factors including Orm1 and Orm2, ceramide synthase, Lcb4 kinase and the Tsc3 subunit of serine palmitoyltransferase as well as extrinsic factors including glucose and iron. Lowering the concentration of glucose, a form of calorie restriction, decreases the level of LCBs, which is consistent with the idea that reducing the level of some sphingolipids enhances lifespan. In contrast, iron deprivation increases LCB levels and decreases long term survival; however, these phenomena may not be related because iron deprivation disrupts many metabolic pathways. The correlation between increased LCBs and shorter lifespan is unsupported at this time. The physiological rise in LCBs that we observe may serve to modulate nutrient transporters and possibly other membrane phenomena that contribute to enhanced stress resistance and survival in stationary phase.► Sphingolipid long-chain bases rise 50-fold by early stationary phase. ► C20-long-chain bases rise to more than 50% of the total in stationary phase cells. ► More than 30% of the newly made C20-long-chain bases go into complex sphingolipids. ► Iron, glucose, and intrinsic factors regulate the rise in long-chain bases. ► Long-chain bases influence long-term survival.

Keywords: Abbreviations; CLS; chronological lifespan; CR; calorie restriction; CS; ceramide synthase; DHS; dihydrosphingosine; LCB; long-chain base; LCBP; long-chain base phosphate; PHS; phytosphingosine; SPT; serine palmitoyltransferaseIron; Sphingolipid; Stationary phase; Yeast; Survival

Distinct composition of human fetal HDL attenuates its anti-oxidative capacity by Ivana Sreckovic; Ruth Birner-Gruenberger; Britta Obrist; Tatjana Stojakovic; Hubert Scharnagl; Michael Holzer; Monika Scholler; Sonia Philipose; Gunther Marsche; Uwe Lang; Gernot Desoye; Christian Wadsack (pp. 737-746).

In human high-density lipoprotein (HDL) represents the major cholesterol carrying lipoprotein class in cord blood, while cholesterol is mainly carried by low-density lipoprotein in maternal serum. Additionally, to carrying cholesterol, HDL also associates with a range of proteins as cargo. We tested the hypothesis that fetal HDL carries proteins qualitatively and quantitatively different from maternal HDL. These differences then contribute to distinct HDL functionality in both circulations. Shotgun proteomics and biochemical analyses were used to assess composition/function of fetal and maternal HDL isolated from uncomplicated human pregnancies at term of gestation. The pattern of analyzed proteins that were statistically elevated in fetal HDL (apoE, proteins involved in coagulation, transport processes) suggests a particle characteristic for the light HDL₂ sub-fraction. In contrast, proteins that were enriched in maternal HDL (apoL, apoF, PON1, apoD, apoCs) have been described almost exclusively in the dense HDL₃ fraction and relevant to its anti-oxidative function and role in innate immunity. Strikingly, PON1 mass and activity were 5-fold lower ( p<0.01) in the fetus, which was accompanied by attenuation of anti-oxidant capacity of fetal HDL. Despite almost equal quantity of CETP in maternal and fetal HDL, its enzymatic activity was 55% lower ( p<0.001) in the fetal circulation, whereas LCAT activity was not altered. These findings indicate that maternally derived HDL differs from fetal HDL with respect to its proteome, size and function. Absence of apoA-1, apoL and PON1 on fetal HDL is associated with decreased anti-oxidative properties together with deficiency in innate immunity collectively indicating distinct HDLs in fetuses.► Fetal HDL carries unique range of proteins as cargo compared to maternal HDL. ► Differences contribute to distinct functionality in both circulations. ► Lack of apoA-1, apoL, and PON1 on fetal HDL is linked to modified functionality.

Keywords: Fetal HDL; PON1; Antioxidative capacity; Apolipoprotein

Caffeic acid phenethyl ester induces adrenoleukodystrophy (Abcd2) gene in human X-ALD fibroblasts and inhibits the proinflammatory response in Abcd1/2 silenced mouse primary astrocytes by Jaspreet Singh; Mushfiquddin Khan; Inderjit Singh (pp. 747-758).

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder caused by mutations in the ABCD1 gene. Accumulation of very long chain fatty acids (VLCFA) that have been attributed to reduced peroxisomal VLCFA β-oxidation activity are the hallmark of the disease. Overexpression of ABCD2 gene, the closest homolog of ABCD1, has been shown to compensate for ABCD1, thus correcting the VLCFA derangement. The accumulation of VLCFA leads to a neuroinflammatory disease process associated with demyelination of the cerebral white matter. The present study underlines the importance of caffeic acid phenethyl ester (CAPE) in inducing the expression of ABCD2 (ALDRP), and normalizing the peroxisomal β-oxidation as well as the levels of saturated and monounsaturated VLCFAs in cultured human skin fibroblasts of X-ALD patients. The expression of ELOVL1, the single elongase catalyzing the synthesis of both saturated VLCFA (C26:0) and mono-unsaturated VLCFA (C26:1), was also reduced by CAPE treatment. Importantly, CAPE upregulated Abcd2 expression and peroxisomal β-oxidation and lowered the VLCFA levels in Abcd1-deficient U87 astrocytes and B12 oligodendrocytes. In addition, using Abcd1/Abcd2-silenced mouse primary astrocytes we examined the effects of CAPE in VLCFA-induced inflammatory response. CAPE treatment decreased the inflammatory response as the expression of inducible nitric oxide synthase, inflammatory cytokine, and activation of NF-κB in Abcd1/Abcd2-silenced mouse primary astrocytes was reduced. The observations indicate that CAPE corrects both the metabolic disease of VLCFA as well as secondary inflammatory disease; therefore, it may be a potential drug candidate to be tested for X-ALD therapy in humans.► CAPE upregulated ABCD2 expression in human skin fibroblasts from X-ALD patients. ► ABCD2 expression was increased in Abcd1-deficient astrocytes and oligodendrocytes. ► Both C26:0 and C26:1 VLCFA levels were reduced in X-ALD patient fibroblasts. ► CAPE inhibited inflammatory response in Abcd1/2-silenced mouse primary astrocytes. ► CAPE may have therapeutic potential for X-ALD.

Keywords: Abbreviations; X-ALD; X-adrenoleukodystrophy; ALDP; adrenoleukodystrophy protein; ALDRP; adrenoleukodystrophy related protein; AMN; adrenomyeloneuropathy; cALD; cerebral adrenoleukodystrophy; DMEM; Dulbecco's modified Eagle's medium; FBS; fetal bovine serum; HBSS; Hanks' balanced salt solution; FAME; fatty acid methyl ester; ELOVL; elongase of very long chain fatty acid; GC; gas chromatography; ROS; reactive oxygen species; Scr; scrambled; CAPE; caffeic acid phenethyl Ester; MBP; myelin basic protein; iNOS; inducible nitric oxide synthase; NO; nitric oxide; TNF-α; tumor necrosis factor-α; VLCFA; very long chain fatty acid; 5-LOX; 5-lipoxygenase; HDAC; histone deacetylase; SAHA; suberoylanilide hydroxamic acid; VPA; valproic acid; SMN; survival of motor neuron; NT; non-targetingX-ALD; Very long chain fatty acid; Glia; Cytokine; ALDP; ABCD2

Trans-10, cis-12 conjugated linoleic acid induced cell death in human colon cancer cells through reactive oxygen species-mediated ER stress by Anne-Sophie Pierre; Mélaine Minville-Walz; Fevre Cécile Fèvre; Aziz Hichami; Joseph Gresti; Laurent Pichon; Sandrine Bellenger; Jérôme Bellenger; François Ghiringhelli; Michel Narce; Mickaël Rialland (pp. 759-768).

Dietary conjugated linoleic acids (CLA) are fatty acid isomers with anticancer activities produced naturally in ruminants or from vegetable oil processing. The anticancer effects of CLA differ upon the cancer origin and the CLA isomers. In this study, we carried out to precise the effects of CLA isomers, c9,t11 and t10,c12 CLA, on mechanisms of cell death induction in colon cancer cells. We first showed that only t10,c12 CLA treatment (25 and 50μM) for 72h triggered apoptosis in colon cancer cells without affecting viability of normal-derived colon epithelial cells. Exposure of colon cancer cells to t10,c12 CLA activated ER stress characterized by induction of eIF2α phoshorylation, splicing of Xbp1 mRNA and CHOP expression. Furthermore, we evidenced that inhibition of CHOP expression and JNK signaling decreased t10,c12 CLA-mediated cancer cell death. Finally, we showed that CHOP induction by t10,c12 CLA was dependent on ROS production and that the anti-oxidant N-acetyl-cysteine reduced CHOP induction-dependent cell death. These results highlight that t10,c12 CLA exerts its cytotoxic effect through ROS generation and a subsequent ER stress-dependent apoptosis in colon cancer cells.► Different effect of CLA isomers on colon cell cancer apoptosis. ► t10,c12 CLA-mediated ER stress. ► t10,c12 CLA-induced cell death is dependent on JNK activation. ► CHOP induction by t10,c12 CLA led to colon cancer cell death. ► t10,c12 CLA-mediated CHOP expression is controlled by ROS generation.

Keywords: Abbreviations; CHOP; C/EBP homologous protein; CLA; Conjugated linoleic acids; ER; Endoplasmic reticulum; IRE1; Inositol requiring enzyme 1; JNK; c-Jun NH(2)-terminal kinase; PERK; RNA-dependent protein kinase (PKR)-like ER kinase; ROS; Reactive oxygen species; UPR; Unfolded protein responseConjugated linoleic acids; Colon cancer; Apoptosis; ER stress; CHOP; Reactive oxygen species

Cholesterol reduction ameliorates glucose-induced calcium handling and insulin secretion in islets from low-density lipoprotein receptor knockout mice by J.C. Souza; E.C Vanzela; R.A. Ribeiro; L.F. Rezende; C.A. de Oliveira; E.M. Carneiro; H.C.F. Oliveira; A.C. Boschero (pp. 769-775).

Changes in cellular cholesterol level may contribute to beta cell dysfunction. Islets from low density lipoprotein receptor knockout (LDLR^−/−) mice have higher cholesterol content and secrete less insulin than wild-type (WT) mice. Here, we investigated the association between cholesterol content, insulin secretion and Ca2⁺ handling in these islets.Isolated islets from both LDLR^−/− and WT mice were used for measurements of insulin secretion (radioimmunoassay), cholesterol content (fluorimetric assay), cytosolic Ca2⁺ level (fura-2AM) and SNARE protein expression (VAMP-2, SNAP-25 and syntaxin-1A). Cholesterol was depleted by incubating the islets with increasing concentrations (0–10mmol/l) of methyl-beta-cyclodextrin (MβCD).The first and second phases of glucose-stimulated insulin secretion (GSIS) were lower in LDLR^−/− than in WT islets, paralleled by an impairment of Ca2⁺ handling in the former. SNAP-25 and VAMP-2, but not syntaxin-1A, were reduced in LDLR^−/− compared with WT islets. Removal of excess cholesterol from LDLR^−/− islets normalized glucose- and tolbutamide-induced insulin release. Glucose-stimulated Ca2⁺ handling was also normalized in cholesterol-depleted LDLR^−/− islets. Cholesterol removal from WT islets by 0.1 and 1.0mmol/l MβCD impaired both GSIS and Ca2⁺ handling. In addition, at 10mmol/l MβCD WT islet showed a loss of membrane integrity and higher DNA fragmentation.Abnormally high (LDLR^−/− islets) or low cholesterol content (WT islets treated with MβCD) alters both GSIS and Ca2⁺ handling. Normalization of cholesterol improves Ca2⁺ handling and insulin secretion in LDLR^−/− islets.► Cholesterol regulates calcium handling and exocytotic processes. ► Cholesterol content in islet-cells regulates insulin secretion. ► Adequate levels of cholesterol are important for pancreatic islet-cells survival. ► High levels of cholesterol may be implicated in Type 2 diabetes.

Keywords: Abbreviations; KRBB; Krebs-Ringer bicarbonate buffer; MβCD; methyl-β-cyclodextrin; RIA; radioimmunoassayCalcium handling; Cholesterol; Glucose; Insulin secretion; LDLR; ^−/−; mice; SNARE proteins

A conserved START domain coenzyme Q-binding polypeptide is required for efficient Q biosynthesis, respiratory electron transport, and antioxidant function in Saccharomyces cerevisiae by Christopher M. Allan; Shauna Hill; Susan Morvaridi; Ryoichi Saiki; Jarrett S. Johnson; Wei-Siang Liau; Kathleen Hirano; Tadashi Kawashima; Ziming Ji; Joseph A. Loo; Jennifer N. Shepherd; Catherine F. Clarke (pp. 776-791).

Coenzyme Q_n (ubiquinone or Q_n) is a redox active lipid composed of a fully substituted benzoquinone ring and a polyisoprenoid tail of n isoprene units. Saccharomyces cerevisiae coq1– coq9 mutants have defects in Q biosynthesis, lack Q₆, are respiratory defective, and sensitive to stress imposed by polyunsaturated fatty acids. The hallmark phenotype of the Q-less yeast coq mutants is that respiration in isolated mitochondria can be rescued by the addition of Q₂, a soluble Q analog. Yeast coq10 mutants share each of these phenotypes, with the surprising exception that they continue to produce Q₆. Structure determination of the Caulobacter crescentus Coq10 homolog (CC1736) revealed a steroidogenic acute regulatory protein-related lipid transfer (START) domain, a hydrophobic tunnel known to bind specific lipids in other START domain family members. Here we show that purified CC1736 binds Q₂, Q₃, Q₁₀, or demethoxy-Q₃ in an equimolar ratio, but fails to bind 3-farnesyl-4-hydroxybenzoic acid, a farnesylated analog of an early Q-intermediate. Over-expression of C. crescentus CC1736 or COQ8 restores respiratory electron transport and antioxidant function of Q₆ in the yeast coq10 null mutant. Studies with stable isotope ring precursors of Q reveal that early Q-biosynthetic intermediates accumulate in the coq10 mutant and de novo Q-biosynthesis is less efficient than in the wild-type yeast or rescued coq10 mutant. The results suggest that the Coq10 polypeptide:Q (protein:ligand) complex may serve essential functions in facilitating de novo Q biosynthesis and in delivering newly synthesized Q to one or more complexes of the respiratory electron transport chain.Display Omitted► Yeast coq10 mutants respire very poorly yet have a normal content of coenzyme Q₆. ► Expression of C. crescentus CC1736 START domain protein rescues the coq10 mutant. ► CC1736 binds Q₃ or demethoxy-Q₃, but doesn't bind 3-farnesyl-4-hydroxybenzoic acid. ► coq-10 mutants show decreased de novo Q synthesis and accumulate Q-intermediates. ► Coq10p facilitates Q biosynthesis and may deliver new Q to respiratory complexes.

Keywords: Abbreviations; αLnn; α-linolenic acid (C18:3,; n; −; 3); BCA; bicinchoninic acid; BHT; butylated hydroxytoluene; BN-PAGE; blue native-polyacrylamide gel electrophoresis; DMQ; demethoxy-Q; DOD; drop out growth medium with dextrose; FHB; farnesyl-hydroxybenzoate; HAB; hexaprenyl-4-aminobenzoic acid; HHB; hexaprenyl-4-hydroxybenzoic acid; HPLC; high performance liquid chromatography; IDMQ; 4-imino-demethoxy-Q; pABA; para; -aminobenzoic acid; PBS; phosphate buffered saline; PUFA; polyunsaturated fatty acid; Q; coenzyme Q or ubiquinone; QH; ₂; coenzyme QH; ₂; or ubiquinol; START; steroidogenic acute regulatory-related lipid transfer; YPD; rich growth medium with dextrose; YPG; rich growth medium with glycerol; YPGal; rich growth medium with galactoseUbiquinone; Yeast mitochondria; Lipid binding; Steroidogenic acute regulatory protein; Respiratory electron transport; Lipid autoxidation

Mammalian alpha beta hydrolase domain (ABHD) proteins: Lipid metabolizing enzymes at the interface of cell signaling and energy metabolism by Caleb C. Lord; Gwynneth Thomas; J. Mark Brown (pp. 792-802).

Dysregulation of lipid metabolism underlies many chronic diseases such as obesity, diabetes, cardiovascular disease, and cancer. Therefore, understanding enzymatic mechanisms controlling lipid synthesis and degradation is imperative for successful drug discovery for these human diseases. Genes encoding α/β hydrolase fold domain (ABHD) proteins are present in virtually all reported genomes, and conserved structural motifs shared by these proteins predict common roles in lipid synthesis and degradation. However, the physiological substrates and products for these lipid metabolizing enzymes and their broader role in metabolic pathways remain largely uncharacterized. Recently, mutations in several members of the ABHD protein family have been implicated in inherited inborn errors of lipid metabolism. Furthermore, studies in cell and animal models have revealed important roles for ABHD proteins in lipid metabolism, lipid signal transduction, and metabolic disease. The purpose of this review is to provide a comprehensive summary surrounding the current state of knowledge regarding mammalian ABHD protein family members. In particular, we will discuss how ABHD proteins are ideally suited to act at the interface of lipid metabolism and signal transduction. Although, the current state of knowledge regarding mammalian ABHD proteins is still in its infancy, this review highlights the potential for the ABHD enzymes as being attractive targets for novel therapies targeting metabolic disease.► α/β-hydrolase domain (ABHD) enzymes regulate glycerophospholipid metabolism. ► Several mutations in ABHD enzymes have been implicated in human diseases. ► ABHD enzymes synthesize or degrade lipids involved in cellular signal transduction. ► ABHD enzymes are attractive targets for new therapies targeting metabolic diseases.

Keywords: Triacylglycerol; Phospholipid; CGI-58; Signal transduction; Endocannabinoid; Serine hydrolase

The human liver fatty acid binding protein (FABP1) gene is activated by FOXA1 and PPARα; and repressed by C/EBPα: Implications in FABP1 down-regulation in nonalcoholic fatty liver disease by Guzman Carla Guzmán; Marta Benet; Sandra Pisonero-Vaquero; Marta Moya; Garcia-Mediavilla M. Victoria García-Mediavilla; Martinez-Chantar M. Luz Martínez-Chantar; Gonzalez-Gallego Javier González-Gallego; José Vicente Castell; Sanchez-Campos Sonia Sánchez-Campos; Ramiro Jover (pp. 803-818).

Liver fatty acid binding protein (FABP1) prevents lipotoxicity of free fatty acids and regulates fatty acid trafficking and partition. Our objective is to investigate the transcription factors controlling the human FABP1 gene and their regulation in nonalcoholic fatty liver disease (NAFLD). Adenovirus-mediated expression of multiple transcription factors in HepG2 cells and cultured human hepatocytes demonstrated that FOXA1 and PPARα are among the most effective activators of human FABP1, whereas C/EBPα is a major dominant repressor. Moreover, FOXA1 and PPARα induced re-distribution of FABP1 protein and increased cytoplasmic expression. Reporter assays demonstrated that the major basal activity of the human FABP1 promoter locates between −96 and −229bp, where C/EBPα binds to a composite DR1-C/EBP element. Mutation of this element at −123bp diminished basal reporter activity, abolished repression by C/EBPα and reduced transactivation by HNF4α. Moreover, HNF4α gene silencing by shRNA in HepG2 cells caused a significant down-regulation of FABP1 mRNA expression. FOXA1 activated the FABP1 promoter through binding to a cluster of elements between −229 and −592bp, whereas PPARα operated through a conserved proximal element at −59bp. Finally, FABP1, FOXA1 and PPARα were concomitantly repressed in animal models of NAFLD and in human nonalcoholic fatty livers, whereas C/EBPα was induced or did not change. We conclude that human FABP1 has a complex mechanism of regulation where C/EBPα displaces HNF4α and hampers activation by FOXA1 and PPARα. Alteration of expression of these transcription factors in NAFLD leads to FABP1 gen repression and could exacerbate lipotoxicity and disease progression.► A model for transcription regulation of human FABP1 gene in liver is proposed. ► HNF4α and FOXA1 contribute to the high constitutive FABP1 transcription. ► PPARα induces FABP1 in response to ligands such as GW7647. ► CEBPα is a repressor, competes with HNF4α and blunts activation by FOXA1 and PPARα. ► Repression of FOXA1 and PPARα is concomitant to FABP1 down-regulation in NAFLD.

Keywords: Abbreviations; C/EBPα; CCAAT/enhancer binding protein alpha; DR1; direct repeat with 1 base spacing; FA; fatty acid; FABP1; fatty acid binding protein 1; FOXA1 (HNF3α); forkhead box A1; GAPDH; glyceraldehyde-3-phosphate dehydrogenase; HNF4α; hepatocyte nuclear factor 4 alpha; LCFA; long-chain fatty acid; LCFA-CoA; long-chain fatty acyl CoA; MAT1A; methionine adenosyltransferase 1A; MCD; methionine- and choline-deficient; MOI; multiplicity of infection; NAFLD; nonalcoholic fatty liver disease; PBGD; porphobilinogen deaminase; PPARα; peroxisome proliferator-activated receptor alpha; PUFA; polyunsaturated fatty acidLiver fatty acid binding protein; Transcription regulation; C/EBPα; FOXA1; HNF4α; Nonalcoholic fatty liver disease

Autophagy: Emerging roles in lipid homeostasis and metabolic control by Patricia Christian; Jennifer Sacco; Khosrow Adeli (pp. 819-824).

Current evidence implicates autophagy in the regulation of lipid stores within the two main organs involved in maintaining lipid homeostasis, the liver and adipose tissue. Critical to this role in hepatocytes is the breakdown of cytoplasmic lipid droplets, a process referred to as lipophagy. Conversely, autophagy is required for adipocyte differentiation and the concurrent accumulation of lipid droplets. Autophagy also affects lipid metabolism through contributions to lipoprotein assembly. A number of reports have now implicated autophagy in the degradation of apolipoprotein B, the main structural protein of very-low-density-lipoprotein. Aberrant autophagy may also be involved in conditions of deregulated lipid homeostasis in metabolic disorders such as the metabolic syndrome. First, insulin signalling and autophagy activity appear to diverge in a mechanism of reciprocal regulation, suggesting a role for autophagy in insulin resistance. Secondly, upregulation of autophagy may lead to conversion of white adipose tissue into brown adipose tissue, thus regulating energy expenditure and obesity. Thirdly, upregulation of autophagy in hepatocytes could increase breakdown of lipid stores controlling triglyceride homeostasis and fatty liver. Taken together, autophagy appears to play a very complex role in lipid homeostasis, affecting lipid stores differently depending on the tissue, as well as contributing to pathways of lipoprotein metabolism.► Autophagic breakdown of cytoplasmic lipid droplets is termed lipophagy. ► Autophagy is needed for differentiation of preadipocytes into white adipocytes. ► Autophagic degradation of apoB downregulates VLDL assembly in hepatocytes. ► Lipophagy-mediated liberation of lipids may play a role in VLDL particle assembly. ► Autophagy is mechanistically linked to obesity, fatty liver and metabolic syndrome.

Keywords: Autophagy; Lipophagy; Apolipoprotein B; Very-low-density-lipoprotein; Metabolic syndrome

Inhibition of cholesteryl ester transfer protein by anacetrapib does not impair the anti-inflammatory properties of high density lipoprotein by Seongah Han; Lauretta LeVoci; Paul Fischer; Sheng-Ping Wang; Karen Gagen; Ying Chen; Dan Xie; Timothy Fisher; Anka G. Ehrhardt; Andrea M. Peier; Douglas G. Johns (pp. 825-833).

Cholesteryl ester transfer protein (CETP) is a target of therapeutic intervention for coronary heart disease. Anacetrapib, a potent inhibitor of CETP, has been shown to reduce LDL-cholesterol by 40% and increase HDL-cholesterol by 140% in patients, and is currently being evaluated in a phase III cardiovascular outcomes trial. HDL is known to possess anti-inflammatory properties, however with such large increases in HDL-cholesterol, it is unclear whether CETP inhibition perturbs HDL functionality such as anti-inflammatory effects on endothelial cells. The purpose of the present study was to determine whether CETP inhibition by anacetrapib affects the anti-inflammatory properties of HDL. HDL was isolated from either hamsters treated with vehicle or anacetrapib for 2weeks, or from normal human subjects treated either placebo, 20mg, or 150mg anacetrapib daily for 2weeks. Anacetrapib treatment increased plasma HDL cholesterol levels by 65% and between 48 and 82% in hamsters and humans, respectively. Pre-incubation of human aortic endothelial cells with HDL isolated from both control and anacetrapib treated hamsters suppressed TNFα induced expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin. Similar results were obtained with human HDL samples pre and post treatment with placebo or anacetrapib. Further, HDL inhibited TNFα-induced MCP-1 secretion, monocyte adhesion and NF-κB activation in endothelial cells, and the inhibition was similar between control and anacetrapib treated groups. These studies demonstrate that anacetrapib treatment does not impair the ability of HDL to suppress an inflammatory response in endothelial cells.► Until now, effects of CETP inhibition on anti-inflammatory properties of HDL were unknown. ► HDL from hamsters and humans suppressed inflammatory responses in endothelial cells. ► This effect was unchanged in HDL from anacetrapib-treated hamsters and humans. ► CETP inhibition by anacetrapib does not impair anti-inflammatory effects of HDL.

Keywords: Cholesteryl ester transfer protein; Anacetrapib; High-density lipoprotein; Endothelial cell; Inflammation

cis-9,trans-11 conjugated linoleic acid stimulates expression of angiopoietin like-4 in the placental extravillous trophoblast cells by Sanjay Basak; Asim K. Duttaroy (pp. 834-843).

A number of studies have been carried out to examine the biological function of conjugated linoleic acid (CLA) and its potential health benefits. However, not much is known about how CLA isomers mediate their effect on angiogenesis and vascularization during early placentation. In this paper we demonstrate that cis-9,trans-11( c9,t11)-CLA stimulated the expression of angiopoietin like-4 (ANGPTL4) mRNA and protein accompanied by tube formation in first trimester placental trophoblast cells, HTR8/SVneo whereas the other CLA isomer, trans-10, cis-12 ( t10,c12)-CLA had no such effects. c9,t11-CLA however did not stimulate expression of the most potent angiogenic factor, vascular endothelial growth factor (VEGF) in these cells. Silencing ANGPTL4 in these cells significantly reduced the stimulatory effect of c9,t11-CLA on tube formation, indicating the involvement of ANGPTL4. In addition, c9,t11-CLA increased the mRNA expression of several pro-angiogenic factors such as fatty acid binding protein-4 (FABP4), cyclooxygenase-2 (COX-2) and adipose differentiation-related protein (ADRP) in HTR8/SVneo cells. c9,t11-CLA also induced the uptake of docosahexaenoic acid, 22:6n−3 (DHA), a stimulator of tube formation in these cells. Triacsin C, an acylCoA synthetase inhibitor, attenuated c9,t11-CLA induced DHA uptake, tube formation and cellular proliferation in HTR8/SVneo cells.Our data suggest that the c9,t11-CLA isomer may regulate angiogenic processes during early placentation via increased expression of ANGPTL4 and other pro-angiogenic factors such as FABP4, COX-2 and ADRP with concomitant increase in the uptake of DHA in these cells.► c9,t11-conjugated linoleic acid stimulates tube formation in trophoblasts cells. ► c9,t11-conjugated linoleic-induced tube formation is mediated mainly via ANGPTL4. ► c9,t11-conjugated linoleic mediated tube formation did not involve VEGF. ► We report that c9,t11-conjugated linoleic acid may help early placentation process.

Keywords: Vascular endothelial growth factor, VEGF; cis-9, trans-11; conjugated linoleic acid,18:2 (; c9t11; -CLA); Angiopoietin like-4, ANGPTL4; HTR8/SVneo; Fatty acid binding protein 4, FABP4; Extravillous trophoblast, EVT

Overexpression of PLIN5 in skeletal muscle promotes oxidative gene expression and intramyocellular lipid content without compromising insulin sensitivity by M. Bosma; L.M. Sparks; G.J. Hooiveld; J.A. Jorgensen; S.M. Houten; P. Schrauwen; S. Kersten; M.K.C. Hesselink (pp. 844-852).

Aims/hypothesis: While lipid deposition in the skeletal muscle is considered to be involved in obesity-associated insulin resistance, neutral intramyocellular lipid (IMCL) accumulation per se does not necessarily induce insulin resistance. We previously demonstrated that overexpression of the lipid droplet coat protein perilipin 2 augments intramyocellular lipid content while improving insulin sensitivity. Another member of the perilipin family, perilipin 5 (PLIN5), is predominantly expressed in oxidative tissues like the skeletal muscle. Here we investigated the effects of PLIN5 overexpression – in comparison with the effects of PLIN2 – on skeletal muscle lipid levels, gene expression profiles and insulin sensitivity. Methods: Gene electroporation was used to overexpress PLIN5 in tibialis anterior muscle of rats fed a high fat diet. Eight days after electroporation, insulin-mediated glucose uptake in the skeletal muscle was measured by means of a hyperinsulinemic euglycemic clamp. Electron microscopy, fluorescence microscopy and lipid extractions were performed to investigate IMCL accumulation. Gene expression profiles were obtained using microarrays. Results: TAG storage and lipid droplet size increased upon PLIN5 overexpression. Despite the higher IMCL content, insulin sensitivity was not impaired and DAG and acylcarnitine levels were unaffected. In contrast to the effects of PLIN2 overexpression, microarray data analysis revealed a gene expression profile favoring FA oxidation and improved mitochondrial function. Conclusions/interpretation: Both PLIN2 and PLIN5 increase neutral IMCL content without impeding insulin-mediated glucose uptake. As opposed to the effects of PLIN2 overexpression, overexpression of PLIN5 in the skeletal muscle promoted expression of a cluster of genes under control of PPARα and PGC1α involved in FA catabolism and mitochondrial oxidation.► PLIN5 overexpression increased TAG storage and lipid droplet size. ► Despite increased IMCL, PLIN5 overexpression did not affect insulin sensitivity. ► PLIN5 increased gene expression of genes involved in fatty acid oxidation. ► The transcriptomic profile was markedly different from effects of PLIN2 overexpression.

Keywords: Abbreviations; ATGL; adipose triglyceride lipase; CGI-58; comparative gene identification-58; DAG; diacylglycerol; FA; fatty acid; GO; gene ontology; GSEA; gene set enrichment analysis; IMCL; intramyocellular lipid; LD; lipid droplet; NES; normalized enrichment score; PLIN; perilipin; TA; tibialis anterior; TAG; triacylglycerolLipid droplet; Perilipin; OXPAT; Skeletal muscle; Insulin sensitivity; Oxidative gene expression

Physicochemical properties of bacterial pro-inflammatory lipids influence their interaction with apolipoprotein-derived peptides by Sunil A. Nankar; Abhay H. Pande (pp. 853-862).

Apolipoprotein-derived peptides have emerged as a promising candidate for the treatment of various inflammatory disease conditions. Multiple mechanisms have been proposed to explain the beneficiary effects of these peptides and prominent among them being high-affinity binding of peptides to pro-inflammatory lipids and facilitating their sequestration/metabolism/clearance in the body. Pro-inflammatory lipids differ considerably in their molecular structures, chemical compositions and physicochemical properties. Importance of the properties of the pro-inflammatory lipids in their ability to bind to apolipoprotein-derived peptides is not studied in details. In this study, we have characterized the interaction of synthetic peptides derived from human apolipoprotein E with lipopolysaccharide (LPS) and lipoteichoic acid (LTA), two potent bacterial pro-inflammatory lipids that differ considerably in their molecular structures and chemical compositions. Binding of the peptides to LPS and LTA was monitored by CD spectroscopy. Effect of the peptides on the biological activity of lipids was studied by monitoring the inhibition of LPS- or LTA-induced up-regulation of the inflammatory markers in the human blood cells. Physicochemical properties of lipid aggregates were determined by fluorescence spectroscopy and native PAGE. Our results show that physicochemical properties of LPS and LTA differ considerably and influence their interaction with apolipoprotein-derived peptides.► Apolipoprotein-derived peptides can act as anti-inflammatory agents ► Peptides exert beneficiary effect by binding to pro-inflammatory lipids ► Physicochemical properties of pro-inflammatory lipids vary widely ► Properties of pro-inflammatory lipids affect their binding abilities to peptides.

Keywords: Abbreviations; ApoE; apolipoprotein E; CD; Circular Dichroism; DPPC; 1,2-dipalmitoyl-; sn; -glycero-3-phosphocholine; di-8-ANEPPS; 4-(2-(6-(dioctylamino)-(2-naphthalenyl)-(ethenyl) 1-(3-sulfopropyl)-pyridinium inner salt; ELISA; enzyme-linked immunosorbent assay; GP; generalized polarization; IL-6; interleukin 6; IL-8; interleukin 8; Laurdan; 2-dimethylamino-(6-lauroyl)-naphthalene; LPS; lipopolysaccharide; LTA; lipoteichoic acid; MCP-1; monocytes chemotactic protein-1; PBS; phosphate buffer saline; POPC; 1-palmitoyl-2-oleoyl-; sn; -glycero-3-phosphocholine; qRT-PCR; quantitative real time polymerase chain reaction; TNF-α; tumor necrosis factor-αApolipoprotein-derived peptide; Inflammation; Lipopolysaccharide; Lipoteichoic acid; Circular dichroism; qRT-PCR

Structural and catalytic insights into the algal prostaglandin H synthase reveal atypical features of the first non-animal cyclooxygenase by Külliki Varvas; Sergo Kasvandik; Kristella Hansen; Jarving Ivar Järving; Indrek Morell; Nigulas Samel (pp. 863-871).

Prostaglandin H synthases (PGHSs) have been identified in the majority of vertebrate and invertebrate animals, and most recently in the red alga Gracilaria vermiculophylla. Here we report on the cloning, expression and characterization of the algal PGHS, which shares only about 20% of the amino acid sequence identity with its animal counterparts, yet catalyzes the conversion of arachidonic acid into prostaglandin-endoperoxides, PGG₂ and PGH₂. The algal PGHS lacks structural elements identified in all known animal PGHSs, such as epidermal growth factor-like domain and helix B in the membrane binding domain. The key residues of animal PGHS, like catalytic Tyr-385 and heme liganding His-388 are conserved in the algal enzyme. However, the amino acid residues shown to be important for substrate binding and coordination, and the target residues for nonsteroidal anti-inflammatory drugs (Arg-120, Tyr-355, and Ser-530) are not found at the appropriate positions in the algal sequences. Differently from animal PGHSs the G. vermiculophylla PGHS easily expresses in Escherichia coli as a fully functional enzyme. The recombinant protein was identified as an oligomeric (evidently tetrameric) ferric heme protein. The preferred substrate for the algal PGHS is arachidonic acid with cyclooxygenase reaction rate remarkably higher than values reported for mammalian PGHS isoforms. Similarly to animal PGHS-2, the algal enzyme is capable of metabolizing ester and amide derivatives of arachidonic acid to corresponding prostaglandin products. Algal PGHS is not inhibited by non-steroidal anti-inflammatory drugs. A single copy of intron-free gene encoding for PGHS was identified in the red algae G. vermiculophylla and Coccotylus truncatus genomes.► Algal (Gv) PGHS, the first non-animal PGHS displays atypical structural features. ► GvPGHS easily expresses in E. coli as a fully functional and highly active enzyme. ► GvPGHS synthesizes prostaglandin products from arachidonic acid and endocannabinoids. ► GvPGHS is not inhibited by non-steroidal anti-inflammatory drugs.

Keywords: Abbreviations; PGHS; prostaglandin H synthase; GvPGHS; Gracilaria vermiculophylla; PGHS; CtPGHS; Coccotylus truncatus; PGHS; huPGHS; human PGHS; AA; arachidonic acid; PG; prostaglandin; AEA; arachidonoyl ethanolamide; AG; arachidonoylglycerol; HPETE; hydroperoxyeicosatetraenoic acid; HETE; hydroxyeicosatetraenoic acid; RACE; rapid amplification of cDNA ends; CHAPS; 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate; TMPD; N,N,N′,N′-tetramethylphenylenediamine; NSAID; non-steroidal anti-inflammatory drug; BN-PAGE; blue native polyacrylamide gel electrophoresis; RP-HPLC; reverse phase high-performance liquid chromatography; TLC; thin layer chromatography; LC-MS; liquid chromatography mass spectrometry; UTR; untranslated region; EGF; epidermal growth factorProstaglandin endoperoxide synthase; Cyclooxygenase; Prostaglandin; Endocannabinoid; Red algae; Gracilaria vermiculophylla

Lipid fingerprints of intact viruses by MALDI-TOF/mass spectrometry by R. Vitale; E. Roine; D.H. Bamford; A. Corcelli (pp. 872-879).

A number of viruses contain lipid membranes, which are in close contact with capsid proteins and/or nucleic acids and have an important role in the viral infection process. In this study membrane lipids of intact viruses have been analysed by MALDI-TOF/MS with a novel methodology avoiding lipid extraction and separation steps. To validate the novel method, a wide screening of viral lipids has been performed analysing highly purified intact bacterial and archaeal viruses displaying different virion architectures. Lipid profiles reported here contain all lipids previously detected by mass spectrometry analyses of virus lipid extracts. Novel details on the membrane lipid composition of selected viruses have also been obtained. In addition we show that this technique allows the study of lipid distribution easily in subviral particles during virus fractionation. The possibility to reliably analyse minute amounts of intact viruses by mass spectrometry opens new perspectives in analytical and functional lipid studies on a wider range of viruses including pathogenic human ones, which are difficult to purify in large amounts.Display Omitted► A new technique for the analysis of viral lipidome is described. ► Intact bacterial and archaeal viruses have been analysed by MALDI-TOF/MS. ► Minute amounts of viruses (approximately 1×10⁷pfu) can be reliably analysed. ► Novel lipid components have been identified in selected viruses. ► Subviral fractions can also be analysed with the new technique.

Keywords: Abbreviations; MALDI-TOF/MS; Matrix-assisted laser desorption ionization time-of-flight/mass spectrometry; TLC; Thin layer chromatography; LC–ESI/MS; Liquid chromatography–electrospray ionization/mass spectrometry; PSD; post source decay; 9-AA; 9-aminoacridine; VP; virion protein; LC; lipid core; HRPV-6; Halorubrum pleomorphic virus 6; HRTV-4; Halorubrum tailed virus 4; PL; phospholipid; CL; cardiolipin; PA; phosphatidic acid; PE; phosphatidylethanolamine; PG; phosphatidylglycerol; PC; phosphatidylcholine; PS; phosphatidylserine; PGS; archaeal analogue of phosphatidylglycerol sulphate; PGP-Me; archaeal analogue of phosphatidylglycerophosphate methyl ester; S-DGD; sulphated-diglycosyl diphytanylglycerol; S-TGD-PA; archaeal glycocardiolipin or sulphated tryglycosyl diphytanil glycerol-phosphatidic acidBacteriophage; Enveloped virus; Archaeal virus; Membrane lipid; Mass spectrometry

Propylisopropylacetic acid (PIA), a constitutional isomer of valproic acid, uncompetitively inhibits arachidonic acid acylation by rat acyl-CoA synthetase 4: A potential drug for bipolar disorder by Hiren R. Modi; Mireille Basselin; Ameer Y. Taha; Lei O. Li; Rosalind A. Coleman; Meir Bialer; Stanley I. Rapoport (pp. 880-886).

Mood stabilizers used for treating bipolar disorder (BD) selectively downregulate arachidonic acid (AA) turnover (deacylation–reacylation) in brain phospholipids, when given chronically to rats. In vitro studies suggest that one of these, valproic acid (VPA), which is teratogenic, reduces AA turnover by inhibiting the brain long-chain acyl-CoA synthetase (Acsl)4 mediated acylation of AA to AA-CoA. We tested whether non-teratogenic VPA analogues might also inhibit Acsl4 catalyzed acylation, and thus have a potential anti-BD action.Rat Acsl4-flag protein was expressed in Escherichia coli, and the ability of three VPA analogues, propylisopropylacetic acid (PIA), propylisopropylacetamide (PID) and N-methyl-2,2,3,3-tetramethylcyclopropanecarboxamide (MTMCD), and of sodium butyrate, to inhibit conversion of AA to AA-CoA by Acsl4 was quantified using Michaelis–Menten kinetics.Acsl4-mediated conversion of AA to AA-CoA in vitro was inhibited uncompetitively by PIA, with a K_i of 11.4mM compared to a published K_i of 25mM for VPA, while PID, MTMCD and sodium butyrate had no inhibitory effect.PIA's ability to inhibit conversion of AA to AA-CoA by Acsl4 in vitro suggests that, like VPA, PIA may reduce AA turnover in brain phospholipids in unanesthetized rats, and if so, may be effective as a non-teratogenic mood stabilizer in BD patients.► Valproic acid's constitutional isomer, PIA, uncompetitively inhibits Acsl4, but does not inhibit histone deacetylase. ► K_i of PIA is 11.4mM, compared to a K_i of 25mM for valproic acid. ► Like VPA, PIA may reduce AA turnover in brain phospholipids in unanesthetized rats. ► If so it may be effective as a non-teratogenic mood stabilizer in BD patients. ► Our in vitro inhibition method with Acsl4 might help to screen for less toxic drugs than valproic acid to treat bipolar disorder

Keywords: Abbreviations; AA; arachidonic acid; Acsl; acyl-CoA synthetase; BD; bipolar disorder; MTMCD; N-methyl-2,2,3,3-tetramethylcyclopropanecarboxamide; PIA; propylisopropylacetic acid; PID; propylisopropylacetamide; VPA; valproic acidBipolar disorder; Valproic acid; Arachidonic acid; Acyl-CoA synthetase 4; Mood stabilizer; Propylisopropylacetic acid; Uncompetitive inhibition

Fat lowers fat: Purified phospholipids as emerging therapies for dyslipidemia by Amirhossein Sahebkar (pp. 887-893).

Dyslipidemia is a major coronary heart disease (CHD) risk factor. In spite of the proven efficacy of statin drugs in reducing CHD burden, there is still much room for the discovery of novel therapeutic agents to address the considerable residual cardiovascular risk that remains after treatment with currently available medications. In particular, there is an urgent demand for drugs capable of boosting the concentration and/or function of high-density lipoprotein (HDL) and apolipoprotein A-I (apo A-I), thereby promoting reverse cholesterol transport. Phospholipids are naturally occurring fats that play indispensible role in human health via their structural, energy storage, signal transduction and metabolic functions. Supplementation with either purified or mixed preparations of bioactive phospholipids has been reported to ameliorate a range of nutritional and cardiovascular disorders. Moreover, several lines of evidence have supported the efficacy of dietary phospholipids in reducing serum and hepatic contents of cholesterol and triglycerides, while increasing HDL-C and apo A-I levels. These beneficial effects of phospholipids could be attributed to their ability in reducing intestinal cholesterol absorption, enhancing biliary cholesterol excretion and modulating the expression and activity of transcriptional factors and enzymes that are involved in lipoprotein metabolism. Given their extreme safety and biocompatibility, dietary supplementation with phospholipid preparations, in particular phosphatidylinositol, appears as a novel and effective strategy that could be used as an alternative or adjunctive therapy to the current medications. The present review outlines the in-vitro, in-vivo and clinical findings on the anti-dyslipidemic effects of three most abundant phospholipids in the human body and diet namely phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol.► The efficacy of currently marketed drugs in the improvement of serum lipid profile is limited. ► Dietary phospholipids are effective in reducing serum and hepatic cholesterol and triglycerides. ► Dietary phospholipids also increase HDL-C and apo A-I levels. ► Dietary phospholipids exert their beneficial effects through affecting cholesterol absorption, metabolism and excretion. ► Dietary phospholipids could serve as effective, safe and biocompatible cardiovascular drugs.

Keywords: Phospholipid; Cardiovascular disease; Lipoprotein; Cholesterol; Triglyceride; Reverse cholesterol transport

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BBA - Molecular and Cell Biology of Lipids (v.1831, #4)