Chondrosarcoma is a malignant cartilage tumor that may arise from benign precursor lesions, such as enchondromas. Some cases of multiple enchondromas are caused by a mutation that results in constitutive activation of Hedgehog-mediated signaling. We found that chondrosarcomas expressed high levels of the Hedgehog target genes PTCH1 and GLI1. Treatment ... More
Overexpression of nicastrin increases Abeta production.
Gamma-secretase cleavage is the final proteolytic step that releases the amyloid beta-peptide (Abeta) from the amyloid beta-protein precursor (APP). Significant evidence indicates that the presenilins (PS) are catalytic components of a high molecular weight gamma-secretase complex. The glycoprotein nicastrin was recently identified as a functional unit of this complex based ... More
Association of excitatory amino acid transporters, especially EAAT2, with cholesterol-rich lipid raft microdomains: importance for excitatory amino acid transporter localization and function.
AuthorsButchbach ME, Tian G, Guo H, Lin CL
JournalJ Biol Chem
PubMed ID15187084
In the present study, we investigated the role of membrane cholesterol in the function of glutamate transporters. Depletion of membrane cholesterol by methyl-beta-cyclodextrin resulted in reduced Na(+)-dependent glutamate uptake in primary cortical cultures. Glial glutamate transporter EAAT2-mediated uptake was more sensitive to this effect. Cell surface biotinylation and immunostaining experiments ... More
Lipid rafts in the maintenance of synapses, dendritic spines, and surface AMPA receptor stability.
AuthorsHering H, Lin CC, Sheng M
JournalJ Neurosci
PubMed ID12716933
'Cholesterol/sphingolipid microdomains (lipid rafts) in the membrane are involved in protein trafficking, formation of signaling complexes, and regulation of actin cytoskeleton. Here, we show that lipid rafts exist abundantly in dendrites of cultured hippocampal neurons, in which they are associated with several postsynaptic proteins including surface AMPA receptors. Depletion of ... More
Involvement of raft-like plasma membrane domains of Entamoeba histolytica in pinocytosis and adhesion.
AuthorsLaughlin RC, McGugan GC, Powell RR, Welter BH, Temesvari LA
JournalInfect Immun
PubMed ID15322032
'Lipid rafts are highly ordered, cholesterol-rich, and detergent-resistant microdomains found in the plasma membrane of many eukaryotic cells. These domains play important roles in endocytosis, secretion, and adhesion in a variety of cell types. The parasitic protozoan Entamoeba histolytica, the causative agent of amoebic dysentery, was determined to have raft-like ... More
Amyloidogenic processing of the Alzheimer beta-amyloid precursor protein depends on lipid rafts.
AuthorsEhehalt R, Keller P, Haass C, Thiele C, Simons K
JournalJ Cell Biol
PubMed ID12515826
'Formation of senile plaques containing the beta-amyloid peptide (A beta) derived from the amyloid precursor protein (APP) is an invariant feature of Alzheimer''s disease (AD). APP is cleaved either by beta-secretase or by alpha-secretase to initiate amyloidogenic (release of A beta) or nonamyloidogenic processing of APP, respectively. A key to ... More
Single-particle tracking of murine polyoma virus-like particles on live cells and artificial membranes.
AuthorsEwers H, Smith AE, Sbalzarini IF, Lilie H, Koumoutsakos P, Helenius A
JournalProc Natl Acad Sci U S A
PubMed ID16219700
'The lateral mobility of individual murine polyoma virus-like particles (VLPs) bound to live cells and artificial lipid bilayers was studied by single fluorescent particle tracking using total internal reflection fluorescence microscopy. The particle trajectories were analyzed in terms of diffusion rates and modes of motion as described by the moment ... More
Novel role for apolipoprotein E in the central nervous system. Modulation of sulfatide content.
'It has long been postulated that apolipoprotein E (apoE) may play a role in lipid metabolism in the brain. However, direct evidence that apoE plays such a role is lacking. We investigated whether apoE isoforms influence lipid content in the brain. We compared the brains of wild-type mice to apoE ... More
AuthorsSteinert S, Lee E, Tresset G, Zhang D, Hortsch R, Wetzel R, Hebbar S, Sundram JR, Kesavapany S, Boschke E, Kraut R,
JournalPLoS ONE
PubMed ID18716682
'BACKGROUND: The uptake and intracellular trafficking of sphingolipids, which self-associate into plasma membrane microdomains, is associated with many pathological conditions, including viral and toxin infection, lipid storage disease, and neurodegenerative disease. However, the means available to label the trafficking pathways of sphingolipids in live cells are extremely limited. In order ... More
Role for influenza virus envelope cholesterol in virus entry and infection.
AuthorsSun X, Whittaker GR
JournalJ Virol
PubMed ID14610177
'Enveloped viruses are highly dependent on their lipid envelopes for entry into and infection of host cells. Here, we have examined the role of cholesterol in the virus envelope, using methyl-beta-cyclodextrin depletion. Pretreatment of virions with methyl-beta-cyclodextrin efficiently depleted envelope cholesterol from influenza virus and significantly reduced virus infectivity in ... More
Caveolin-induced activation of the phosphatidylinositol 3-kinase/Akt pathway increases arsenite cytotoxicity.
AuthorsShack S, Wang XT, Kokkonen GC, Gorospe M, Longo DL, Holbrook NJ
JournalMol Cell Biol
PubMed ID12640124
'The inhibitory effect of caveolin on the cellular response to growth factor stimulation is well established. Given the significant overlap in signaling pathways involved in regulating cell proliferation and stress responsiveness, we hypothesized that caveolin would also affect a cell''s ability to respond to environmental stress. Here we investigated the ... More
Acyl-coenzyme A:cholesterol acyltransferase promotes oxidized LDL/oxysterol-induced apoptosis in macrophages.
AuthorsFreeman NE, Rusinol AE, Linton M, Hachey DL, Fazio S, Sinensky MS, Thewke D
JournalJ Lipid Res
PubMed ID15995174
'7-Ketocholesterol (7KC) is a cytotoxic component of oxidized low density lipoproteins (OxLDLs) and induces apoptosis in macrophages by a mechanism involving the activation of cytosolic phospholipase A2 (cPLA2). In the current study, we examined the role of ACAT in 7KC-induced and OxLDL-induced apoptosis in murine macrophages. An ACAT inhibitor, Sandoz ... More
Raft composition at physiological temperature and pH in the absence of detergents.
AuthorsAyuyan AG, Cohen FS,
JournalBiophys J
PubMed ID17993486
'Biological rafts were identified and isolated at 37 degrees C and neutral pH. The strategy for isolating rafts utilized membrane tension to generate large domains. For lipid compositions that led only to microscropically unresolvable rafts in lipid bilayers, membrane tension led to the appearance of large, observable rafts. The large ... More
Characterisation of Weibel-Palade body fusion by amperometry in endothelial cells reveals fusion pore dynamics and the effect of cholesterol on exocytosis.
AuthorsCookson EA, Conte IL, Dempster J, Hannah MJ, Carter T,
Journal
PubMed ID24127569
'Regulated secretion from endothelial cells is mediated by Weibel-Palade body (WPB) exocytosis. Plasma membrane cholesterol is implicated in regulating secretory granule exocytosis and fusion pore dynamics; however, its role in modulating WPB exocytosis is not clear. To address this we combined high-resolution electrochemical analysis of WPB fusion pore dynamics, by ... More
Cholesterol-induced caveolin targeting to lipid droplets in adipocytes: a role for caveolar endocytosis.
AuthorsLe Lay S, Hajduch E, Lindsay MR, Le Lièpvre X, Thiele C, Ferré P, Parton RG, Kurzchalia T, Simons K, Dugail I
JournalTraffic
PubMed ID16643278
'We have investigated the targeting of caveolin to lipid bodies in adipocytes that express high levels of caveolins and contain well-developed lipid droplets. We observed that the lipid droplets isolated from adipocytes of caveolin-1 knock out mice contained dramatically reduced levels of cholesterol, indicating that caveolin is required for maintaining ... More
Ceramide displaces cholesterol from lipid rafts and decreases the association of the cholesterol binding protein caveolin-1.
AuthorsYu C, Alterman M, Dobrowsky RT
JournalJ Lipid Res
PubMed ID15863835
'Addition of exogenous ceramide causes a significant displacement of cholesterol in lipid raft model membranes. However, whether ceramide-induced cholesterol displacement is sufficient to alter the protein composition of caveolin-enriched lipid raft membranes is unknown. Therefore, we examined whether increasing endogenous ceramide levels with bacterial sphingomyelinase (bSMase) depleted cholesterol and changed ... More
Inhibition of capacitation-associated tyrosine phosphorylation signaling in rat sperm by epididymal protein Crisp-1.
AuthorsRoberts KP, Wamstad JA, Ensrud KM, Hamilton DW
JournalBiol Reprod
PubMed ID12700197
'Ejaculated sperm are unable to fertilize an egg until they undergo capacitation. Capacitation results in the acquisition of hyperactivated motility, changes in the properties of the plasma membrane, including changes in proteins and glycoproteins, and acquisition of the ability to undergo the acrosome reaction. In all mammalian species examined, capacitation ... More
Sodium benzoate, a metabolite of cinnamon and a food additive, reduces microglial and astroglial inflammatory responses.
AuthorsBrahmachari S, Jana A, Pahan K,
JournalJ Immunol
PubMed ID19812204
'Upon activation, microglia and astrocytes produce a number of proinflammatory molecules that participate in the pathophysiology of several neurodegenerative disorders. This study explores the anti-inflammatory property of cinnamon metabolite sodium benzoate (NaB) in microglia and astrocytes. NaB, but not sodium formate, was found to inhibit LPS-induced expression of inducible NO ... More
Annexin A6-balanced late endosomal cholesterol controls influenza a replication and propagation.
AuthorsMusiol A, Gran S, Ehrhardt C, Ludwig S, Grewal T, Gerke V, Rescher U,
Journal
PubMed ID24194536
'Influenza is caused by influenza A virus (IAV), an enveloped, negative-stranded RNA virus that derives its envelope lipids from the host cell plasma membrane. Here, we examined the functional role of cellular cholesterol in the IAV infection cycle. We show that shifting of cellular cholesterol pools via the Ca(2+)-regulated membrane-binding ... More
A model of flux regulation in the cholesterol biosynthesis pathway: Immune mediated graduated flux reduction versus statin-like led stepped flux reduction.
AuthorsWatterson S, Guerriero ML, Blanc M, Mazein A, Loewe L, Robertson KA, Gibbs H, Shui G, Wenk MR, Hillston J, Ghazal P,
JournalBiochimie
PubMed ID22664637
'The cholesterol biosynthesis pathway has recently been shown to play an important role in the innate immune response to viral infection with host protection occurring through a coordinate down regulation of the enzymes catalysing each metabolic step. In contrast, statin based drugs, which form the principle pharmaceutical agents for decreasing ... More
Internalization of beta-amyloid peptide by primary neurons in the absence of apolipoprotein E.
AuthorsSaavedra L, Mohamed A, Ma V, Kar S, de Chaves EP,
JournalJ Biol Chem
PubMed ID17911110
'Extracellular accumulation of beta-amyloid peptide (Abeta) has been linked to the development of Alzheimer disease. The importance of intraneuronal Abeta has been recognized more recently. Although considerable evidence indicates that extracellular Abeta contributes to the intracellular pool of Abeta, the mechanisms involved in Abeta uptake by neurons are poorly understood. ... More
'Nitric oxide (NO) signaling is inextricably linked to both its physical and chemical properties. Due to its preferentially hydrophobic solubility, NO molecules tend to partition from the aqueous milieu into biological membranes. We hypothesized that plasma membrane ordering provided by cholesterol further couples the physics of NO diffusion with cellular ... More
Direct effect of cholesterol on insulin secretion: a novel mechanism for pancreatic beta-cell dysfunction.
AuthorsHao M, Head WS, Gunawardana SC, Hasty AH, Piston DW,
JournalDiabetes
PubMed ID17575085
'OBJECTIVE: Type 2 diabetes is often accompanied by abnormal blood lipid and lipoprotein levels, but most studies on the link between hyperlipidemia and diabetes have focused on free fatty acids (FFAs). In this study, we examined the relationship between cholesterol and insulin secretion from pancreatic beta-cells that is independent of ... More
Down-regulation of endogenous amyloid precursor protein processing due to cellular aging.
AuthorsKern A, Roempp B, Prager K, Walter J, Behl C
JournalJ Biol Chem
PubMed ID16303768
'Processing of amyloid precursor protein (APP) is a well acknowledged central pathogenic mechanism in Alzheimer disease. However, influences of age-associated cellular alterations on the biochemistry of APP processing have not been studied in molecular detail so far. Here, we report that processing of endogenous APP is down-regulated during the aging ... More
Knockdown of ACAT-1 reduces amyloidogenic processing of APP.
AuthorsHuttunen HJ, Greco C, Kovacs DM
JournalFEBS Lett
PubMed ID17412327
'Previous studies have shown that acyl-coenzyme A:cholesterol acyl transferase (ACAT), an enzyme that controls cellular equilibrium between free cholesterol and cholesteryl esters, modulates proteolytic processing of APP in cell-based and animal models of Alzheimer''s disease. Here we report that ACAT-1 RNAi reduced cellular ACAT-1 protein by approximately 50% and cholesteryl ... More
A method of direct measurement for the enzymatic determination of cholesteryl esters.
AuthorsMizoguchi T, Edano T, Koshi T
JournalJ Lipid Res
PubMed ID14563821
'A direct measurement method for the enzymatic determination of cholesteryl esters (CEs) without measuring total cholesterol (TC) and free cholesterol (FC) is described. In the first step, hydrogen peroxide generated by cholesterol oxidase from FC was decomposed by catalase. In the second step, CE was measured by enzymatic determination using ... More
Fluorometric method for the enzymatic determination of cholesterol.
AuthorsAmundson DM, Zhou M
JournalJ Biochem Biophys Methods
PubMed ID10078872
A fluorometric method for the enzymatic determination of cholesterol content has been developed using a novel fluorogenic H2O2 probe, Amplex Red. This assay is performed in a 96-well microplate, and it is a one-step method amenable to automated procedures. Using commercially available cholesterol, our assay allows detection of 5 pmol ... More
Deletion of Cdkn1b ameliorates hyperglycemia by maintaining compensatory hyperinsulinemia in diabetic mice.
AuthorsUchida T, Nakamura T, Hashimoto N, Matsuda T, Kotani K, Sakaue H, Kido Y, Hayashi Y, Nakayama KI, White MF, Kasuga M
JournalNat Med
PubMed ID15685168
The protein p27(Kip1) regulates cell cycle progression in mammals by inhibiting the activity of cyclin-dependent kinases (CDKs). Here we show that p27(Kip1) progressively accumulates in the nucleus of pancreatic beta cells in mice that lack either insulin receptor substrate 2 (Irs2(-/-)) or the long form of the leptin receptor (Lepr(-/-) ... More
Co-localization of cholesterol, apolipoprotein E and fibrillar Abeta in amyloid plaques.
AuthorsBurns MP, Noble WJ, Olm V, Gaynor K, Casey E, LaFrancois J, Wang L, Duff K
JournalBrain Res Mol Brain Res
PubMed ID12573540
Recent evidence strongly suggests a role for cholesterol and apolipoprotein E in the etiology of Alzheimer's disease. We have demonstrated the co-localization of cholesterol and apolipoprotein E with beta-amyloid immunoreactivity and thioflavin S immunofluorescence in AD type plaques of a transgenic mouse model. Cholesterol and apolipoprotein E co-localized to the ... More
All-trans retinoic acid-triggered antimicrobial activity against Mycobacterium tuberculosis is dependent on NPC2.
AuthorsWheelwright M, Kim EW, Inkeles MS, De Leon A, Pellegrini M, Krutzik SR, Liu PT,
Journal
PubMed ID24501203
A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the mechanism is unclear. In this study, we demonstrate that vitamin A-triggered antimicrobial activity against M. tuberculosis requires expression of NPC2. Comparison of monocytes stimulated with all-trans retinoic acid ... More
Adenovirus RIDa uncovers a novel pathway requiring ORP1L for lipid droplet formation independent of NPC1.
AuthorsCianciola NL, Greene DJ, Morton RE, Carlin CR,
Journal
PubMed ID24025716
Niemann-Pick disease type C (NPC) is caused by mutations in NPC1 or NPC2, which coordinate egress of low-density-lipoprotein (LDL)-cholesterol from late endosomes. We previously reported that the adenovirus-encoded protein RIDa rescues the cholesterol storage phenotype in NPC1-mutant fibroblasts. We show here that RIDa reconstitutes deficient endosome-to-endoplasmic reticulum (ER) transport, allowing ... More
Statins reduce amyloid-beta production through inhibition of protein isoprenylation.
Epidemiological evidence suggests that long term treatment with hydroxymethylglutaryl-CoA reductase inhibitors, or statins, decreases the risk for developing Alzheimer disease (AD). However, statin-mediated AD protection cannot be fully explained by reduction of cholesterol levels. In addition to their cholesterol lowering effects, statins have pleiotropic actions and act to lower the ... More
Independent inhibition of Alzheimer disease beta- and gamma-secretase cleavage by lowered cholesterol levels.
The major molecular risk factor for Alzheimer disease so far identified is the amyloidogenic peptide Abeta(42). In addition, growing evidence suggests a role of cholesterol in Alzheimer disease pathology and Abeta generation. However, the cellular mechanism of lipid-dependent Abeta production remains unclear. Here we describe that the two enzymatic activities ... More
Sequestration of free cholesterol in cell membranes by prions correlates with cytoplasmic phospholipase A2 activation.
AuthorsBate C, Tayebi M, Williams A,
JournalBMC Biol
PubMed ID18269734
BACKGROUND: The transmissible spongiform encephalopathies (TSEs), otherwise known as the prion diseases, occur following the conversion of the normal cellular prion protein (PrPC) to an alternatively folded isoform (PrPSc). The accumulation of PrPSc within the brain leads to neurodegeneration through an unidentified mechanism. Since many neurodegenerative disorders including prion, Parkinson's ... More
MicroRNA-148a regulates LDL receptor and ABCA1 expression to control circulating lipoprotein levels.
AuthorsGoedeke L, Rotllan N, Canfrán-Duque A, Aranda JF, Ramírez CM, Araldi E, Lin CS, Anderson NN, Wagschal A, de Cabo R, Horton JD, Lasunción MA, Näär AM, Suárez Y, Fernández-Hernando C,
Journal
PubMed ID26437365
The hepatic low-density lipoprotein receptor (LDLR) pathway is essential for clearing circulating LDL cholesterol (LDL-C). Whereas the transcriptional regulation of LDLR is well characterized, the post-transcriptional mechanisms that govern LDLR expression are just beginning to emerge. Here we develop a high-throughput genome-wide screening assay to systematically identify microRNAs (miRNAs) that ... More
Cholesterol synthesis and import contribute to protective cholesterol increments in acute myeloid leukemia cells.
AuthorsBanker DE, Mayer SJ, Li HY, Willman CL, Appelbaum FR, Zager RA,
JournalBlood
PubMed ID15161671
Cholesterol levels are abnormally increased in many acute myeloid leukemia (AML) samples exposed in vitro to chemotherapy. Blocking these acute cholesterol responses selectively sensitizes AML cells to therapeutics. Thus, defining the molecular mechanisms by which AML cells accomplish these protective cholesterol increments might elucidate novel therapeutic targets. We now report ... More
Free fatty acid transport across adipocytes is mediated by an unknown membrane protein pump.
AuthorsKampf JP, Parmley D, Kleinfeld AM,
JournalAm J Physiol Endocrinol Metab
PubMed ID17711989
The role of cell membranes in regulating the flux of long chain free fatty acids (FFA) into and out of adipocytes is intensely debated. Four different membrane proteins including, FABPpm, CD36/FAT, caveolin-1, and FATP have been identified as facilitating FFA transport. Moreover, CD36 and caveolin-1 are also reported to mediate ... More
Cholesterol level regulates endosome motility via Rab proteins.
AuthorsChen H, Yang J, Low PS, Cheng JX,
JournalBiophys J
PubMed ID17981910
The role of cholesterol in the regulation of endosome motility was investigated by monitoring the intracellular trafficking of endocytosed folate receptors (FRs) labeled with fluorescent folate conjugates. Real-time fluorescence imaging of HeLa cells transfected with green fluorescent protein-tubulin revealed that FR-containing endosomes migrate along microtubules. Moreover, microinjection with antibodies that ... More
Cytoskeletal control of CD36 diffusion promotes its receptor and signaling function.
The mechanisms that govern receptor coalescence into functional clusters--often a critical step in their stimulation by ligand--are poorly understood. We used single-molecule tracking to investigate the dynamics of CD36, a clustering-responsive receptor that mediates oxidized LDL uptake by macrophages. We found that CD36 motion in the membrane was spatially structured ... More
Endogenous 24(S),25-epoxycholesterol fine-tunes acute control of cellular cholesterol homeostasis.
AuthorsWong J, Quinn CM, Gelissen IC, Brown AJ,
JournalJ Biol Chem
PubMed ID17981807
Certain oxysterols, when added to cultured cells, are potent regulators of cholesterol homeostasis, decreasing cholesterol synthesis and uptake and increasing cholesterol efflux. However, very little is known about whether or not endogenous oxysterol(s) plays a significant role in cholesterol homeostasis. 24(S),25-Epoxycholesterol (24,25EC) is unique among oxysterols in that it is ... More
Opposite effects of simvastatin on the bactericidal and inflammatory response of macrophages to opsonized S. aureus.
AuthorsBenati D, Ferro M, Savino MT, Ulivieri C, Schiavo E, Nuccitelli A, Pasini FL, Baldari CT,
JournalJ Leukoc Biol
PubMed ID19892847
Besides lowering circulating cholesterol, statins act as immunomodulators. Although the effects of statins on lymphocyte activation and differentiation have been clearly defined, there is no consensus as to effects of these drugs on phagocytes. We have addressed the outcome of simvastatin treatment on the activation and effector function of human ... More
Consequences of the selective blockage of chaperone-mediated autophagy.
AuthorsMassey AC, Kaushik S, Sovak G, Kiffin R, Cuervo AM
JournalProc Natl Acad Sci U S A
PubMed ID16585521
Chaperone-mediated autophagy (CMA) is a selective pathway for the degradation of cytosolic proteins in lysosomes. CMA declines with age because of a decrease in the levels of lysosome-associated membrane protein (LAMP) type 2A, a lysosomal receptor for this pathway. We have selectively blocked the expression of LAMP-2A in mouse fibroblasts ... More
Unbiased quantitative proteomics of lipid rafts reveals high specificity for signaling factors.
AuthorsFoster LJ, De Hoog CL, Mann M
JournalProc Natl Acad Sci U S A
PubMed ID12724530
Membrane lipids were once thought to be homogenously distributed in the 2D surface of a membrane, but the lipid raft theory suggests that cholesterol and sphingolipids partition away from other membrane lipids. Lipid raft theory further implicates these cholesterol-rich domains in many processes such as signaling and vesicle traffic. However, ... More
A role for myosin-1A in the localization of a brush border disaccharidase.
AuthorsTyska MJ, Mooseker MS
JournalJ Cell Biol
PubMed ID15138292
To gain insight regarding myosin-1A (M1A) function, we expressed a dominant negative fragment of this motor in the intestinal epithelial cell line, CACO-2BBE. Sucrase isomaltase (SI), a transmembrane disaccharidase found in microvillar lipid rafts, was missing from the brush border (BB) in cells expressing this fragment. Density gradient centrifugation, affinity ... More
Regulation of cholesterol and sphingomyelin metabolism by amyloid-beta and presenilin.
AuthorsGrimm MO, Grimm HS, Pätzold AJ, Zinser EG, Halonen R, Duering M, Tschäpe JA, De Strooper B, Müller U, Shen J, Hartmann T
JournalNat Cell Biol
PubMed ID16227967
Amyloid beta peptide (Abeta) has a key role in the pathological process of Alzheimer's disease (AD), but the physiological function of Abeta and of the amyloid precursor protein (APP) is unknown. Recently, it was shown that APP processing is sensitive to cholesterol and other lipids. Hydroxymethylglutaryl-CoA reductase (HMGR) and sphingomyelinases ... More
Signaling-dependent immobilization of acylated proteins in the inner monolayer of the plasma membrane.
AuthorsCorbett-Nelson EF, Mason D, Marshall JG, Collette Y, Grinstein S
JournalJ Cell Biol
PubMed ID16831891
Phospholipids play a critical role in the recruitment and activation of several adaptors and effectors during phagocytosis. Changes in lipid metabolism during phagocytosis are restricted to the phagocytic cup, the area of the plasmalemma lining the target particle. It is unclear how specific lipids and lipid-associated molecules are prevented from ... More
Dietary n-3 polyunsaturated fatty acids promote activation-induced cell death in Th1-polarized murine CD4+ T-cells.
AuthorsSwitzer KC, Fan YY, Wang N, McMurray DN, Chapkin RS
JournalJ Lipid Res
PubMed ID15145980
Dietary n-3 PUFAs have been shown to attenuate T-cell-mediated inflammation. To investigate whether dietary n-3 PUFAs promote activation-induced cell death (AICD) in CD4+ T-cells induced in vitro to a polarized T-helper1 (Th1) phenotype, C57BL/6 mice were fed diets containing either 5% corn oil (CO; n-6 PUFA control) or 4% fish ... More
Phospholipase Cdelta4 is required for Ca2+ mobilization essential for acrosome reaction in sperm.
AuthorsFukami K, Yoshida M, Inoue T, Kurokawa M, Fissore RA, Yoshida N, Mikoshiba K, Takenawa T
JournalJ Cell Biol
PubMed ID12695499
Zona pellucida (ZP)-induced acrosome reaction in sperm is a required step for mammalian fertilization. However, the precise mechanism of the acrosome reaction remains unclear. We previously reported that PLCdelta4 is involved in the ZP-induced acrosome reaction in mouse sperm. Here we have monitored Ca2+ responses in single sperm, and we ... More
Cholesterol depletion induces solid-like regions in the plasma membrane.
AuthorsNishimura SY, Vrljic M, Klein LO, McConnell HM, Moerner WE
JournalBiophys J
PubMed ID16272447
Glycosylphosphatidylinositol-linked and transmembrane major histocompatibility complex (MHC) class II I-E(k) proteins, as well as N-(6-tetramethylrhodaminethiocarbamoyl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (Tritc-DHPE), are used as probes to determine the effect of cholesterol concentration on the organization of the plasma membrane at temperatures in the range 22 degrees C-42 degrees C. Cholesterol depletion caused a decrease in ... More
Activation of membrane cholesterol by displacement from phospholipids.
AuthorsLange Y, Ye J, Steck TL
JournalJ Biol Chem
PubMed ID16129675
We tested the hypothesis that certain membrane-intercalating agents increase the chemical activity of cholesterol by displacing it from its low activity association with phospholipids. Octanol, 1,2-dioctanoyl-sn-glycerol (a diglyceride), and N-hexanoyl-D-erythrosphingosine (a ceramide) were shown to increase both the rate of transfer and the extent of equilibrium partition of human red ... More
Measurement of cholesterol bidirectional flux between cells and lipoproteins.
AuthorsZimetti F, Weibel GK, Duong M, Rothblat GH
JournalJ Lipid Res
PubMed ID16327021
We developed an assay that quantitates bidirectional cholesterol flux between cells and lipoproteins. Incubating Fu5AH cells with increasing concentrations of human serum resulted in increased influx and efflux; however, influx was 2- to 3-fold greater at all serum concentrations. With apolipoprotein B (apoB)-depleted serum, the ratio of influx to efflux ... More
OxLDL increases endothelial stiffness, force generation, and network formation.
AuthorsByfield FJ, Tikku S, Rothblat GH, Gooch KJ, Levitan I
JournalJ Lipid Res
PubMed ID16418538
This study investigates the effect of oxidatively modified low density lipoprotein (OxLDL) on the biomechanical properties of human aortic endothelial cells (HAECs). We show that treatment with OxLDL results in a 90% decrease in the membrane deformability of HAECs, as determined by micropipette aspiration. Furthermore, aortic endothelial cells freshly isolated ... More
Disturbed cholesterol traffic but normal proteolytic function in LAMP-1/LAMP-2 double-deficient fibroblasts.
AuthorsEskelinen EL, Schmidt CK, Neu S, Willenborg M, Fuertes G, Salvador N, Tanaka Y, Lüllmann-Rauch R, Hartmann D, Heeren J, von Figura K, Knecht E, Saftig P
JournalMol Biol Cell
PubMed ID15121881
Mice double deficient in LAMP-1 and -2 were generated. The embryos died between embryonic days 14.5 and 16.5. An accumulation of autophagic vacuoles was detected in many tissues including endothelial cells and Schwann cells. Fibroblast cell lines derived from the double-deficient embryos accumulated autophagic vacuoles and the autophagy protein LC3II ... More
Cholesterol modulates the membrane binding and intracellular distribution of annexin 6.
Authors de Diego Iñaki; Schwartz Felix; Siegfried Heide; Dauterstedt Paul; Heeren Joerg; Beisiegel Ulrike; Enrich Carlos; Grewal Thomas;
JournalJ Biol Chem
PubMed ID12070178
Annexins are Ca(2+)- and phospholipid-binding proteins that are widely expressed in mammalian tissues and that bind to different cellular membranes. In recent years its role in membrane traffic has emerged as one of its predominant functions, but the regulation of its intracellular distribution still remains unclear. We demonstrated that annexin ... More
Cholesterol is essential for macrophage inflammatory protein 1 beta binding and conformational integrity of CC chemokine receptor 5.
AuthorsNguyen DH, Taub D
JournalBlood
PubMed ID12036855
The chemokine receptor, CCR5, is used as a human immunodeficiency virus coreceptor in combination with CD4 during transmission and early infection. CCR5 has been shown to be palmitoylated and targeted to cholesterol- and sphingolipid-rich membrane microdomains termed "lipid rafts." However, the role of cholesterol and lipid rafts on chemokine binding ... More
Cholesterol depletion suppresses the translational diffusion of class II major histocompatibility complex proteins in the plasma membrane.
AuthorsVrljic M, Nishimura SY, Moerner WE, McConnell HM
JournalBiophys J
PubMed ID15516525
Glycosylphosphatidylinositol (GPI)-linked and native major histocompatibility complex class II I-E(k) were used as probes to determine the effect of varying cholesterol concentration on the mobility of proteins in the plasma membrane. These proteins were imaged in Chinese hamster ovary cells using single-molecule fluorescence microscopy. Observed diffusion coefficients of both native ... More
Quaternary ammonium beta-cyclodextrin nanoparticles for enhancing doxorubicin permeability across the in vitro blood-brain barrier.
AuthorsGil ES, Li J, Xiao H, Lowe TL,
JournalBiomacromolecules
PubMed ID19216528
This study describes novel quaternary ammonium beta-cyclodextrin (QAbetaCD) nanoparticles as drug delivery carriers for doxorubicin (DOX), a hydrophobic anticancer drug, across the blood-brain barrier (BBB). QAbetaCD nanoparticles show 65-88 nm hydrodynamic radii with controllable cationic properties by adjusting the incorporated amount of quaternary ammonium group in their structure. ATR-FTIR studies ... More
Differential effects of modification of membrane cholesterol and sphingolipids on the conformation, function, and trafficking of the G protein-coupled cholecystokinin receptor.
AuthorsHarikumar KG, Puri V, Singh RD, Hanada K, Pagano RE, Miller LJ
JournalJ Biol Chem
PubMed ID15537636
The lipid microenvironment of receptors can influence their conformation, function, and regulation. Cholecystokinin (CCK)-stimulated signaling is abnormal in some forms of hyperlipidemia, suggesting the possibility of unique sensitivity to its lipid environment. Here we examined the influence of cholesterol and sphingolipids on CCK receptors in model Chinese hamster ovary cell ... More
CD44 interaction with Na+-H+ exchanger (NHE1) creates acidic microenvironments leading to hyaluronidase-2 and cathepsin B activation and breast tumor cell invasion.
AuthorsBourguignon LY, Singleton PA, Diedrich F, Stern R, Gilad E
JournalJ Biol Chem
PubMed ID15090545
We have explored CD44 (a hyaluronan (HA) receptor) interaction with a Na(+)-H(+) exchanger (NHE1) and hyaluronidase-2 (Hyal-2) during HA-induced cellular signaling in human breast tumor cells (MDA-MB-231 cell line). Immunological analyses demonstrate that CD44s (standard form) and two signaling molecules (NHE1 and Hyal-2) are closely associated in a complex in ... More
Disruption of lipid rafts inhibits P2X1 receptor-mediated currents and arterial vasoconstriction.
AuthorsVial C, Evans RJ
JournalJ Biol Chem
PubMed ID16006561
P2X1 receptors for ATP are ligand-gated cation channels expressed on a range of smooth muscle preparations and blood platelets. The receptors appear to be clustered close to sympathetic nerve varicosities and mediate the underlying membrane potential changes and constriction following nerve stimulation in a range of arteries and resistance arterioles. ... More
Lipid rafts and HIV pathogenesis: host membrane cholesterol is required for infection by HIV type 1.
AuthorsLiao Z, Cimakasky LM, Hampton R, Nguyen DH, Hildreth JE
JournalAIDS Res Hum Retroviruses
PubMed ID11485618
In a previous study we showed that budding of HIV-1 particles occurs at highly specialized membrane microdomains known as lipid rafts. These microdomains are characterized by a distinct lipid composition that includes high concentrations of cholesterol, sphingolipids, and glycolipids. Since cholesterol is known to play a key role in the ... More
Cholesterol is required for endocytosis and endosomal escape of adenovirus type 2.
AuthorsImelli N, Meier O, Boucke K, Hemmi S, Greber UF
JournalJ Virol
PubMed ID14990728
The species C adenovirus type 2 (Ad2) and Ad5 bind the coxsackievirus B Ad receptor and alphav integrin coreceptors and enter epithelial cells by clathrin-mediated endocytosis. This pathway is rapid and efficient. It leads to cell activation and the cholesterol-dependent formation of macropinosomes. Macropinosomes are triggered to release their contents ... More
Vaccinia virus penetration requires cholesterol and results in specific viral envelope proteins associated with lipid rafts.
AuthorsChung CS, Huang CY, Chang W
JournalJ Virol
PubMed ID15650188
Vaccinia virus infects a wide variety of mammalian cells from different hosts, but the mechanism of virus entry is not clearly defined. The mature intracellular vaccinia virus contains several envelope proteins mediating virion adsorption to cell surface glycosaminoglycans; however, it is not known how the bound virions initiate virion penetration ... More
Modulation of the bilayer thickness of exocytic pathway membranes by membrane proteins rather than cholesterol.
AuthorsMitra K, Ubarretxena-Belandia I, Taguchi T, Warren G, Engelman DM
JournalProc Natl Acad Sci U S A
PubMed ID15016920
A biological membrane is conceptualized as a system in which membrane proteins are naturally matched to the equilibrium thickness of the lipid bilayer. Cholesterol, in addition to lipid composition, has been suggested to be a major regulator of bilayer thickness in vivo because measurements in vitro have shown that cholesterol ... More
The lipofuscin fluorophore A2E perturbs cholesterol metabolism in retinal pigment epithelial cells.
AuthorsLakkaraju A, Finnemann SC, Rodriguez-Boulan E
JournalProc Natl Acad Sci U S A
PubMed ID17578916
Proteins involved in cholesterol trafficking are known to contribute to the pathogenesis of atherosclerosis and Alzheimer's disease. Allelic variants in the cholesterol transporters apolipoprotein E and ATP-binding cassette protein A1 (ABCA1) have recently been associated with susceptibility to age-related macular degeneration (AMD). Histopathological analyses of eyes with AMD demonstrate the ... More
Requirements for CEACAMs and cholesterol during murine coronavirus cell entry.
AuthorsThorp EB, Gallagher TM
JournalJ Virol
PubMed ID14990688
Previous reports have documented that cholesterol supplementations increase cytopathic effects in tissue culture and also intensify in vivo pathogenicities during infection by the enveloped coronavirus murine hepatitis virus (MHV). To move toward a mechanistic understanding of these phenomena, we used growth media enriched with methyl-beta-cyclodextrin or cholesterol to reduce or ... More
Protection by cholesterol-extracting cyclodextrins: a role for N-methyl-D-aspartate receptor redistribution.
AuthorsAbulrob A, Tauskela JS, Mealing G, Brunette E, Faid K, Stanimirovic D
JournalJ Neurochem
PubMed ID15748165
Cyclodextrins (CDs) are cyclic oligosaccharides composed of a lipophilic central cavity and a hydrophilic outer surface. Some CDs are capable of extracting cholesterol from cell membranes and can affect function of receptors and proteins localized in cholesterol-rich membrane domains. In this report, we demonstrate the neuroprotective activity of some CD ... More