1
|
Steck TL, Lange Y. Is reverse cholesterol transport regulated by active cholesterol? J Lipid Res 2023; 64:100385. [PMID: 37169287 PMCID: PMC10279919 DOI: 10.1016/j.jlr.2023.100385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/02/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023] Open
Abstract
This review considers the hypothesis that a small portion of plasma membrane cholesterol regulates reverse cholesterol transport in coordination with overall cellular homeostasis. It appears that almost all of the plasma membrane cholesterol is held in stoichiometric complexes with bilayer phospholipids. The minor fraction of cholesterol that exceeds the complexation capacity of the phospholipids is called active cholesterol. It has an elevated chemical activity and circulates among the organelles. It also moves down its chemical activity gradient to plasma HDL, facilitated by the activity of ABCA1, ABCG1, and SR-BI. ABCA1 initiates this process by perturbing the organization of the plasma membrane bilayer, thereby priming its phospholipids for translocation to apoA-I to form nascent HDL. The active excess sterol and that activated by ABCA1 itself follow the phospholipids to the nascent HDL. ABCG1 similarly rearranges the bilayer and sends additional active cholesterol to nascent HDL, while SR-BI simply facilitates the equilibration of the active sterol between plasma membranes and plasma proteins. Active cholesterol also flows downhill to cytoplasmic membranes where it serves both as a feedback signal to homeostatic ER proteins and as the substrate for the synthesis of mitochondrial 27-hydroxycholesterol (27HC). 27HC binds the LXR and promotes the expression of the aforementioned transport proteins. 27HC-LXR also activates ABCA1 by competitively displacing its inhibitor, unliganded LXR. § Considerable indirect evidence suggests that active cholesterol serves as both a substrate and a feedback signal for reverse cholesterol transport. Direct tests of this novel hypothesis are proposed.
Collapse
Affiliation(s)
- Theodore L Steck
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Yvonne Lange
- Department of Pathology, Rush University Medical Center, Chicago, IL, USA.
| |
Collapse
|
2
|
Astrinidis A, Li C, Zhang EY, Zhao X, Zhao S, Guo M, Olatoke T, Mattam U, Huang R, Zhang AG, Pitstick L, Kopras EJ, Gupta N, Jandarov R, Smith EP, Fugate E, Lindquist D, Markiewski MM, Karbowniczek M, Wikenheiser-Brokamp KA, Setchell KDR, McCormack FX, Xu Y, Yu JJ. Upregulation of acid ceramidase contributes to tumor progression in tuberous sclerosis complex. JCI Insight 2023; 8:e166850. [PMID: 36927688 PMCID: PMC10243802 DOI: 10.1172/jci.insight.166850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is characterized by multisystem, low-grade neoplasia involving the lung, kidneys, brain, and heart. Lymphangioleiomyomatosis (LAM) is a progressive pulmonary disease affecting almost exclusively women. TSC and LAM are both caused by mutations in TSC1 and TSC2 that result in mTORC1 hyperactivation. Here, we report that single-cell RNA sequencing of LAM lungs identified activation of genes in the sphingolipid biosynthesis pathway. Accordingly, the expression of acid ceramidase (ASAH1) and dihydroceramide desaturase (DEGS1), key enzymes controlling sphingolipid and ceramide metabolism, was significantly increased in TSC2-null cells. TSC2 negatively regulated the biosynthesis of tumorigenic sphingolipids, and suppression of ASAH1 by shRNA or the inhibitor ARN14976 (17a) resulted in markedly decreased TSC2-null cell viability. In vivo, 17a significantly decreased the growth of TSC2-null cell-derived mouse xenografts and short-term lung colonization by TSC2-null cells. Combined rapamycin and 17a treatment synergistically inhibited renal cystadenoma growth in Tsc2+/- mice, consistent with increased ASAH1 expression and activity being rapamycin insensitive. Collectively, the present study identifies rapamycin-insensitive ASAH1 upregulation in TSC2-null cells and tumors and provides evidence that targeting aberrant sphingolipid biosynthesis pathways has potential therapeutic value in mechanistic target of rapamycin complex 1-hyperactive neoplasms, including TSC and LAM.
Collapse
Affiliation(s)
- Aristotelis Astrinidis
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Chenggang Li
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Erik Y. Zhang
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Xueheng Zhao
- Clinical Mass Spectrometry Laboratory, Division of Pathology and Laboratory Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Shuyang Zhao
- Divisions of Pulmonary Biology and Biomedical Informatics, Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Minzhe Guo
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Divisions of Pulmonary Biology and Biomedical Informatics, Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Tasnim Olatoke
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Ushodaya Mattam
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Rong Huang
- Clinical Mass Spectrometry Laboratory, Division of Pathology and Laboratory Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Alan G. Zhang
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Lori Pitstick
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Elizabeth J. Kopras
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Nishant Gupta
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Roman Jandarov
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Eric P. Smith
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Elizabeth Fugate
- Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Diana Lindquist
- Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Maciej M. Markiewski
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas, USA
| | - Magdalena Karbowniczek
- Department of Immunotherapeutics and Biotechnology, Jerry H. Hodge School of Pharmacy, Texas Tech University Health Sciences Center, Abilene, Texas, USA
| | - Kathryn A. Wikenheiser-Brokamp
- Division of Pathology and Laboratory Medicine; Division of Pulmonary Medicine; and Division of Pulmonary Biology, Section of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Kenneth D. R. Setchell
- Clinical Mass Spectrometry Laboratory, Division of Pathology and Laboratory Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Francis X. McCormack
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Yan Xu
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Divisions of Pulmonary Biology and Biomedical Informatics, Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Jane J. Yu
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| |
Collapse
|
3
|
Peluso AA, Lundgaard AT, Babaei P, Mousovich-Neto F, Rocha AL, Damgaard MV, Bak EG, Gnanasekaran T, Dollerup OL, Trammell SAJ, Nielsen TS, Kern T, Abild CB, Sulek K, Ma T, Gerhart-Hines Z, Gillum MP, Arumugam M, Ørskov C, McCloskey D, Jessen N, Herrgård MJ, Mori MAS, Treebak JT. Oral supplementation of nicotinamide riboside alters intestinal microbial composition in rats and mice, but not humans. NPJ AGING 2023; 9:7. [PMID: 37012386 PMCID: PMC10070358 DOI: 10.1038/s41514-023-00106-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 03/20/2023] [Indexed: 04/05/2023]
Abstract
The gut microbiota impacts systemic levels of multiple metabolites including NAD+ precursors through diverse pathways. Nicotinamide riboside (NR) is an NAD+ precursor capable of regulating mammalian cellular metabolism. Some bacterial families express the NR-specific transporter, PnuC. We hypothesized that dietary NR supplementation would modify the gut microbiota across intestinal sections. We determined the effects of 12 weeks of NR supplementation on the microbiota composition of intestinal segments of high-fat diet-fed (HFD) rats. We also explored the effects of 12 weeks of NR supplementation on the gut microbiota in humans and mice. In rats, NR reduced fat mass and tended to decrease body weight. Interestingly, NR increased fat and energy absorption but only in HFD-fed rats. Moreover, 16S rRNA gene sequencing analysis of intestinal and fecal samples revealed an increased abundance of species within Erysipelotrichaceae and Ruminococcaceae families in response to NR. PnuC-positive bacterial strains within these families showed an increased growth rate when supplemented with NR. The abundance of species within the Lachnospiraceae family decreased in response to HFD irrespective of NR. Alpha and beta diversity and bacterial composition of the human fecal microbiota were unaltered by NR, but in mice, the fecal abundance of species within Lachnospiraceae increased while abundances of Parasutterella and Bacteroides dorei species decreased in response to NR. In conclusion, oral NR altered the gut microbiota in rats and mice, but not in humans. In addition, NR attenuated body fat mass gain in rats, and increased fat and energy absorption in the HFD context.
Collapse
Affiliation(s)
- A Augusto Peluso
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Agnete T Lundgaard
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Parizad Babaei
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Felippe Mousovich-Neto
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Andréa L Rocha
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Mads V Damgaard
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emilie G Bak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thiyagarajan Gnanasekaran
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ole L Dollerup
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Samuel A J Trammell
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas S Nielsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Timo Kern
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline B Abild
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Karolina Sulek
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Herlev Hospital, Herlev, Denmark
| | - Tao Ma
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Zach Gerhart-Hines
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew P Gillum
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Manimozhiyan Arumugam
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Douglas McCloskey
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Niels Jessen
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Markus J Herrgård
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
- BioInnovation Institute, Copenhagen, Denmark
| | - Marcelo A S Mori
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Obesity and Comorbidities Research Center, University of Campinas, Campinas, SP, Brazil
- Experimental Medicine Research Cluster, University of Campinas, Campinas, SP, Brazil
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
4
|
Kotlyarov S, Kotlyarova A. Clinical Significance of Lipid Transport Function of ABC Transporters in the Innate Immune System. MEMBRANES 2022; 12:1083. [PMID: 36363640 PMCID: PMC9698216 DOI: 10.3390/membranes12111083] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/25/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
ABC transporters are a large family of proteins that transport a variety of substrates across cell plasma membranes. Because of this, they are involved in many physiological processes. It is of interest to note that many ABC transporters are involved in the transport of various lipids. In addition, this function may be related to the innate immune system. The evidence that ABC transporters are involved in the regulation of the innate immune system through the transport of various substances greatly enhances the understanding of their clinical significance. ABC transporters are involved in the cellular homeostasis of cholesterol as well as in the regulation of its content in lipid rafts. Through these mechanisms, they can regulate the function of membrane proteins, including receptors of the innate immune system. By regulating lipid transport, some members of ABC transporters are involved in phagocytosis. In addition, ABC transporters are involved in the transport of lipopolysaccharide, lipid mediators of inflammation, and perform other functions in the innate immune system.
Collapse
Affiliation(s)
- Stanislav Kotlyarov
- Department of Nursing, Ryazan State Medical University, 390026 Ryazan, Russia
| | - Anna Kotlyarova
- Department of Pharmacy Management and Economics, Ryazan State Medical University, 390026 Ryazan, Russia
| |
Collapse
|
5
|
Sato Y, Kawashima K, Fukui E, Matsumoto H, Yoshizawa F, Sato Y. Functional analysis reveals that Tinagl1 is required for normal muscle development in mice through the activation of ERK signaling. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119294. [PMID: 35597451 DOI: 10.1016/j.bbamcr.2022.119294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/21/2022] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
Tinagl1 (tubulointerstitial nephritis antigen-like 1) is a matricellular protein involved in female infertility and breast cancer tumorigenesis. In this study, we analyzed the function of Tinagl1 in skeletal muscle using knockout mice and cell experiments. Although primary myoblasts isolated from Tinagl1-decifient (Tinagl1-/-) mice differentiated into normal myotubes, and treatment with recombinant Tinagl1 did not affect the proliferation or differentiation of C2C12 myoblasts, Tinagl1-/- mice exhibited reduced body mass and calf muscle weights compared to the control group (Tinagl1flox/flox). Furthermore, Tinagl1-/- mice showed myofibers with centrally located nuclei, which is a morphological marker of regenerating muscle or myopathy. In addition, the capillary density in the soleus muscle of Tinagl1-/- mice showed a decreasing trend compared to that of the control group. Importantly, si-RNA-mediated knockdown of TINAGL1 resulted in reduced tube formation in human umbilical vein endothelial cells (HUVECs), whereas treatment with Tinagl1 promoted tube formation. Immunoblot analysis revealed that Tinagl1 activates ERK signaling in both HUVECs and C2C12 myoblasts and myotubes, which are involved in the regulation of myogenic differentiation, proliferation, metabolism, and angiogenesis. Our results demonstrate that Tinagl1 may be required for normal muscle and capillary development through the activation of ERK signaling.
Collapse
Affiliation(s)
- Yoriko Sato
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto 8628652, Japan
| | - Keisuke Kawashima
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Tochigi, 3218505, Japan
| | - Emiko Fukui
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Tochigi, 3218505, Japan
| | - Hiromichi Matsumoto
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Tochigi, 3218505, Japan
| | - Fumiaki Yoshizawa
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Tochigi, 3218505, Japan
| | - Yusuke Sato
- Department of Animal Science, School of Agriculture, Tokai University, Kumamoto 8628652, Japan.
| |
Collapse
|
6
|
Patanapirunhakit P, Karlsson H, Mulder M, Ljunggren S, Graham D, Freeman D. Sphingolipids in HDL - Potential markers for adaptation to pregnancy? Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158955. [PMID: 33933650 DOI: 10.1016/j.bbalip.2021.158955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 11/15/2022]
Abstract
Plasma high density lipoprotein (HDL) exhibits many functions that render it an effective endothelial protective agent and may underlie its potential role in protecting the maternal vascular endothelium during pregnancy. In non-pregnant individuals, the HDL lipidome is altered in metabolic disease compared to healthy individuals and is linked to reduced cholesterol efflux, an effect that can be reversed by lifestyle management. Specific sphingolipids such as sphingosine-1-phosphate (S1P) have been shown to mediate the vaso-dilatory effects of plasma HDL via interaction with the endothelial nitric oxide synthase pathway. This review describes the relationship between plasma HDL and vascular function during healthy pregnancy and details how this is lost in pre-eclampsia, a disorder of pregnancy associated with widespread endothelial dysfunction. Evidence of a role for HDL sphingolipids, in particular S1P and ceramide, in cardiovascular disease and in healthy pregnancy and pre-eclampsia is discussed. Available data suggest that HDL-S1P and HDL-ceramide can mediate vascular protection in healthy pregnancy but not in preeclampsia. HDL sphingolipids thus are of potential importance in the healthy maternal adaptation to pregnancy.
Collapse
Affiliation(s)
- Patamat Patanapirunhakit
- Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand; Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
| | - Helen Karlsson
- Occupational and Environmental Medicine Center, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
| | - Monique Mulder
- Division of Pharmacology, Vascular and Metabolic Diseases, Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, the Netherlands.
| | - Stefan Ljunggren
- Occupational and Environmental Medicine Center, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
| | - Delyth Graham
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
| | - Dilys Freeman
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
| |
Collapse
|
7
|
Kuge H, Miyamoto I, Yagyu KI, Honke K. PLRP2 selectively localizes synaptic membrane proteins via acyl-chain remodeling of phospholipids. J Lipid Res 2020; 61:1747-1763. [PMID: 32963038 PMCID: PMC7707162 DOI: 10.1194/jlr.ra120001087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The plasma membrane of neurons consists of distinct domains, each of which carries specialized functions and a characteristic set of membrane proteins. While this compartmentalized membrane organization is essential for neuronal functions, it remains controversial how neurons establish these domains on the laterally fluid membrane. Here, using immunostaining, lipid-MS analysis and gene ablation with the CRISPR/Cas9 system, we report that the pancreatic lipase-related protein 2 (PLRP2), a phospholipase A1 (PLA1), is a key organizer of membrane protein localization at the neurite tips of PC12 cells. PLRP2 produced local distribution of 1-oleoyl-2-palmitoyl-PC at these sites through acyl-chain remodeling of membrane phospholipids. The resulting lipid domain assembled the syntaxin 4 (Stx4) protein within itself by selectively interacting with the transmembrane domain of Stx4. The localized Stx4, in turn, facilitated the fusion of transport vesicles that contained the dopamine transporter with the domain of the plasma membrane, which led to the localized distribution of the transporter to that domain. These results revealed the pivotal roles of PLA1, specifically PLRP2, in the formation of functional domains in the plasma membrane of neurons. In addition, our results suggest a mode of membrane organization in which the local acyl-chain remodeling of membrane phospholipids controls the selective localization of membrane proteins by regulating both lipid-protein interactions and the fusion of transport vesicles to the lipid domain.
Collapse
Affiliation(s)
- Hideaki Kuge
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan.
| | - Izumi Miyamoto
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan
| | - Ken-Ichi Yagyu
- Science Research Center, Kochi University Medical School, Nankoku, Kochi, Japan
| | - Koichi Honke
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan.
| |
Collapse
|
8
|
Zhao Y, Xu H, Tian Z, Wang X, Xu L, Li K, Gao X, Fan D, Ma X, Ling W, Yang Y. Dose-dependent reductions in plasma ceramides after anthocyanin supplementation are associated with improvements in plasma lipids and cholesterol efflux capacity in dyslipidemia: A randomized controlled trial. Clin Nutr 2020; 40:1871-1878. [PMID: 33131908 DOI: 10.1016/j.clnu.2020.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/02/2020] [Accepted: 10/10/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND & AIMS Plasma ceramides have been identified as novel risk factors for metabolic and cardiovascular diseases. We aimed to evaluate the effects of dietary anthocyanins on plasma ceramides and to disentangle whether the alterations in ceramides could be related with those in other cardiometabolic risk factors in the dyslipidemia. METHODS In a randomized double-blinded placebo-controlled trial, 176 eligible dyslipidemia subjects were randomly assigned into four groups receiving placebo, 40, 80, or 320 mg/day anthocyanins, respectively for 12 weeks. RESULTS A total of 169 subjects completed the study. After 12-week intervention, dietary anthocyanins dose-dependently reduced plasma concentrations of all six ceramide species in the dyslipidemia subjects (all Ptrend values < 0.05). Specifically, 320 mg/day anthocyanins effectively lowered plasma N-palmitoylsphingosine (Cer 16:0, mean change: -28.3 ± 41.2 versus 2.9 ± 38.2, nmol/L, P = 0.018) and N-tetracosanoylsphingosine (Cer 24:0, mean change: -157.1 ± 493.9 versus 10.7 ± 439.9, nmol/L, P = 0.002) compared with the placebo. The declines in plasma Cer 16:0 and Cer 24:0 were significantly correlated with the decreases in plasma non-high-density lipoprotein cholesterol (nonHDL-C, Spearman's r = 0.32, P = 0.040 for Cer 16:0; Spearman's r = 0.35, P = 0.026 for Cer 24:0), apolipoprotein B (Spearman's r = 0.33, P = 0.031 for Cer 16:0; Spearman's r = 0.48, P = 0.002 for Cer 24:0), and total cholesterol (Spearman's r = 0.34, P = 0.026 for Cer 16:0; Spearman's r = 0.31, P = 0.042 for Cer 24:0) after 12-week 320 mg/day anthocyanin administration. Besides, we found that anthocyanins at 320 mg/day also markedly enhanced cholesterol efflux capacity in the dyslipidemia, the changes of which were positively associated with the reductions in Cer 16:0 (Spearman's r = 0.42, P = 0.006) independent of HDL-C and apolipoprotein A-I. CONCLUSIONS Reductions in plasma Cer 16:0 and Cer 18:0 after 12-week anthocyanin intervention were dose-dependently associated with improvements in plasma lipids and cholesterol efflux capacity in the dyslipidemia. CLINICAL TRIAL REGISTRATION The study was registered at ClinicalTrials.gov with the identifier No. NCT03415503.
Collapse
Affiliation(s)
- Yimin Zhao
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Huihui Xu
- Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China; Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zezhong Tian
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xu Wang
- Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China; Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Lin Xu
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Kongyao Li
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaoli Gao
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Die Fan
- Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China; Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xilin Ma
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenhua Ling
- Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China; Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yan Yang
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, Sun Yat-sen University, Guangzhou, Guangdong, China; Guangdong Engineering Technology Center of Nutrition Transformation, Sun Yat-sen University, Guangzhou, Guangdong, China.
| |
Collapse
|
9
|
Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux. Pharmaceut Med 2020; 33:465-498. [PMID: 31933239 PMCID: PMC7101889 DOI: 10.1007/s40290-019-00308-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.
Collapse
|
10
|
Fournier N, Benoist JF, Allaoui F, Nowak M, Dakroub H, Vedie B, Paul JL. Contrasting effects of membrane enrichment with polyunsaturated fatty acids on phospholipid composition and cholesterol efflux from cholesterol-loaded J774 mouse or primary human macrophages. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158536. [PMID: 31672574 DOI: 10.1016/j.bbalip.2019.158536] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 08/30/2019] [Accepted: 09/24/2019] [Indexed: 12/15/2022]
Abstract
A high consumption of polyunsaturated fatty acids (PUFAs), particularly n-3 PUFAs, is atheroprotective. PUFAs incorporation into membrane phospholipids alters the functionality of membrane proteins. We studied the consequences of the in vitro supplementation of several PUFAs on the FA profiles and on ABCA1-dependent cholesterol efflux capacities from cholesterol-loaded macrophages. Arachidonic acid (AA, C20:4 n-6) and, to a lesser extent, eicosapentaenoic acid (EPA, C20:5 n-3), dose-dependently impaired cholesterol efflux from cholesterol-loaded J774 mouse macrophages without alterations in ABCA1 expression, whereas docosahexaenoic acid (DHA, C22:6 n-3) had no impact. AA cells exhibited higher proportions of arachidonic acid and adrenic acid (C22:4 n-6), its elongation product. EPA cells exhibited slightly higher proportions of EPA associated with much higher proportions of docosapentaenoic acid (C22:5 n-3), its elongation product and with lower proportions of AA. Conversely, both EPA and DHA and, to a lesser extent, AA decreased cholesterol efflux from cholesterol-loaded primary human macrophages (HMDM). The differences observed in FA profiles after PUFA supplementations were different from those observed for the J774 cells. In conclusion, we are the first to report that AA and EPA, but not DHA, have deleterious effects on the cardioprotective ABCA1 cholesterol efflux pathway from J774 foam cells. Moreover, the membrane incorporation of PUFAs does not have the same impact on cholesterol efflux from murine (J774) or human (HMDM) cholesterol-loaded macrophages. This finding emphasizes the key role of the cellular model in cholesterol efflux studies and may partly explain the heterogeneous literature data on the impact of PUFAs on cholesterol efflux.
Collapse
Affiliation(s)
- Natalie Fournier
- Lip(Sys)(2) - EA 7357, Athérosclérose: homéostasie et trafic du cholestérol des macrophages, Univ. Paris-Sud, Université Paris-Saclay, UFR de Pharmacie, 92290 Châtenay-Malabry, France; Laboratoire de Biochimie, AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Européen Georges Pompidou, 75015 Paris, France.
| | - Jean-François Benoist
- Lip(Sys)(2) - EA 7357, Athérosclérose: homéostasie et trafic du cholestérol des macrophages, Univ. Paris-Sud, Université Paris-Saclay, UFR de Pharmacie, 92290 Châtenay-Malabry, France; Laboratoire de Biochimie hormonale, AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Robert Debré, 75019 Paris, France
| | - Fatima Allaoui
- Lip(Sys)(2) - EA 7357, Athérosclérose: homéostasie et trafic du cholestérol des macrophages, Univ. Paris-Sud, Université Paris-Saclay, UFR de Pharmacie, 92290 Châtenay-Malabry, France
| | - Maxime Nowak
- Lip(Sys)(2) - EA 7357, Athérosclérose: homéostasie et trafic du cholestérol des macrophages, Univ. Paris-Sud, Université Paris-Saclay, UFR de Pharmacie, 92290 Châtenay-Malabry, France
| | - Hani Dakroub
- Lip(Sys)(2) - EA 7357, Athérosclérose: homéostasie et trafic du cholestérol des macrophages, Univ. Paris-Sud, Université Paris-Saclay, UFR de Pharmacie, 92290 Châtenay-Malabry, France
| | - Benoît Vedie
- Laboratoire de Biochimie, AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Européen Georges Pompidou, 75015 Paris, France
| | - Jean-Louis Paul
- Lip(Sys)(2) - EA 7357, Athérosclérose: homéostasie et trafic du cholestérol des macrophages, Univ. Paris-Sud, Université Paris-Saclay, UFR de Pharmacie, 92290 Châtenay-Malabry, France; Laboratoire de Biochimie, AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Européen Georges Pompidou, 75015 Paris, France
| |
Collapse
|
11
|
Vaidya M, Jentsch JA, Peters S, Keul P, Weske S, Gräler MH, Mladenov E, Iliakis G, Heusch G, Levkau B. Regulation of ABCA1-mediated cholesterol efflux by sphingosine-1-phosphate signaling in macrophages. J Lipid Res 2019; 60:506-515. [PMID: 30655318 DOI: 10.1194/jlr.m088443] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 01/16/2019] [Indexed: 12/21/2022] Open
Abstract
Sphingolipid and cholesterol metabolism are closely associated at the structural, biochemical, and functional levels. Although HDL-associated sphingosine-1-phosphate (S1P) contributes to several HDL functions, and S1P signaling regulates glucose and lipid metabolism, no study has addressed the involvement of S1P in cholesterol efflux. Here, we show that sphingosine kinase (Sphk) activity was induced by the LXR agonist 22(R)-hydroxycholesterol and required for the stimulation of ABCA1-mediated cholesterol efflux to apolipoprotein A-I. In support, pharmacological Sphk inhibition and Sphk2 but not Sphk1 deficiency abrogated efflux. The involved mechanism included stimulation of both transcriptional and functional ABCA1 regulatory pathways and depended for the latter on the S1P receptor 3 (S1P3). Accordingly, S1P3-deficient macrophages were resistant to 22(R)-hydroxycholesterol-stimulated cholesterol efflux. The inability of excess exogenous S1P to further increase efflux was consistent with tonic S1P3 signaling by a pool of constitutively generated Sphk-derived S1P dynamically regulating cholesterol efflux. In summary, we have established S1P as a previously unrecognized intermediate in LXR-stimulated ABCA1-mediated cholesterol efflux and identified S1P/S1P3 signaling as a positive-feedback regulator of cholesterol efflux. This constitutes a novel regulatory mechanism of cholesterol efflux by sphingolipids.
Collapse
Affiliation(s)
- Mithila Vaidya
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany.,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| | - Julian A Jentsch
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany.,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| | - Susann Peters
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany.,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| | - Petra Keul
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany.,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| | - Sarah Weske
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany.,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| | - Markus H Gräler
- Department of Anesthesiology and Intensive Care Medicine University Hospital Jena, Jena, Germany.,Center for Sepsis Control and Care, University Hospital Jena, Jena, Germany.,Center for Molecular Biomedicine University Hospital Jena, Jena, Germany
| | - Emil Mladenov
- Institute of Medical Radiation Biology University Hospital Essen, University of Duisburg-Essen, Duisburg, Germany
| | - George Iliakis
- Institute of Medical Radiation Biology University Hospital Essen, University of Duisburg-Essen, Duisburg, Germany
| | - Gerd Heusch
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany.,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| | - Bodo Levkau
- Institute for Pathophysiology, University of Duisburg-Essen, Duisburg, Germany .,West German Heart and Vascular Center University of Duisburg-Essen, Duisburg, Germany
| |
Collapse
|
12
|
Oldoni F, van Capelleveen JC, Dalila N, Wolters JC, Heeren J, Sinke RJ, Hui DY, Dallinga-Thie GM, Frikke-Schmidt R, Hovingh KG, van de Sluis B, Tybjærg-Hansen A, Kuivenhoven JA. Naturally Occurring Variants in LRP1 (Low-Density Lipoprotein Receptor-Related Protein 1) Affect HDL (High-Density Lipoprotein) Metabolism Through ABCA1 (ATP-Binding Cassette A1) and SR-B1 (Scavenger Receptor Class B Type 1) in Humans. Arterioscler Thromb Vasc Biol 2018; 38:1440-1453. [PMID: 29853565 PMCID: PMC6023722 DOI: 10.1161/atvbaha.117.310309] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— Studies into the role of LRP1 (low-density lipoprotein receptor–related protein 1) in human lipid metabolism are scarce. Although it is known that a common variant in LRP1 (rs116133520) is significantly associated with HDL-C (high-density lipoprotein cholesterol), the mechanism underlying this observation is unclear. In this study, we set out to study the functional effects of 2 rare LRP1 variants identified in subjects with extremely low HDL-C levels. Approach and Results— In 2 subjects with HDL-C below the first percentile for age and sex and moderately elevated triglycerides, we identified 2 rare variants in LRP1: p.Val3244Ile and p.Glu3983Asp. Both variants decrease LRP1 expression and stability. We show in a series of translational experiments that these variants culminate in reduced trafficking of ABCA1 (ATP-binding cassette A1) to the cell membrane. This is accompanied by an increase in cell surface expression of SR-B1 (scavenger receptor class B type 1). Combined these effects may contribute to low HDL-C levels in our study subjects. Supporting these findings, we provide epidemiological evidence that rs116133520 is associated with apo (apolipoprotein) A1 but not with apoB levels. Conclusions— This study provides the first evidence that rare variants in LRP1 are associated with changes in human lipid metabolism. Specifically, this study shows that LRP1 may affect HDL metabolism by virtue of its effect on both ABCA1 and SR-B1.
Collapse
Affiliation(s)
- Federico Oldoni
- From the Department of Pediatrics, Section of Molecular Genetics, University Medical Centre Groningen, University of Groningen, The Netherlands (F.O., J.C.W., B.v.d.S., J.A.K.)
| | | | - Nawar Dalila
- Department of Clinical Biochemistry, Rigshospitalet (N.D., R.F.-S., A.T.-H.)
| | - Justina C Wolters
- From the Department of Pediatrics, Section of Molecular Genetics, University Medical Centre Groningen, University of Groningen, The Netherlands (F.O., J.C.W., B.v.d.S., J.A.K.)
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Germany (J.H.)
| | - Richard J Sinke
- Department of Genetics, University Medical Centre Groningen, The Netherlands (R.J.S.)
| | - David Y Hui
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati College of Medicine, OH (D.Y.H.)
| | - Geesje M Dallinga-Thie
- Department of Vascular Medicine (J.C.v.C., G.M.D.-T., K.G.H.).,Department Experimental Vascular Medicine (G.M.D.-T.), Academic Medical Center, Amsterdam, The Netherlands
| | - Ruth Frikke-Schmidt
- Department of Clinical Biochemistry, Rigshospitalet (N.D., R.F.-S., A.T.-H.)
| | - Kees G Hovingh
- Department of Vascular Medicine (J.C.v.C., G.M.D.-T., K.G.H.)
| | - Bart van de Sluis
- From the Department of Pediatrics, Section of Molecular Genetics, University Medical Centre Groningen, University of Groningen, The Netherlands (F.O., J.C.W., B.v.d.S., J.A.K.)
| | - Anne Tybjærg-Hansen
- Department of Clinical Biochemistry, Rigshospitalet (N.D., R.F.-S., A.T.-H.).,Copenhagen City Heart Study, Frederiksberg Hospital (A.T.-H.), Copenhagen University Hospital and Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jan Albert Kuivenhoven
- From the Department of Pediatrics, Section of Molecular Genetics, University Medical Centre Groningen, University of Groningen, The Netherlands (F.O., J.C.W., B.v.d.S., J.A.K.)
| |
Collapse
|
13
|
Phillips MC. Is ABCA1 a lipid transfer protein? J Lipid Res 2018; 59:749-763. [PMID: 29305383 DOI: 10.1194/jlr.r082313] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/02/2018] [Indexed: 12/16/2022] Open
Abstract
ABCA1 functions as a lipid transporter because it mediates the transfer of cellular phospholipid (PL) and free (unesterified) cholesterol (FC) to apoA-I and related proteins present in the extracellular medium. ABCA1 is a membrane PL translocase and its enzymatic activity leads to transfer of PL molecules from the cytoplasmic leaflet to the exofacial leaflet of a cell plasma membrane (PM). The presence of active ABCA1 in the PM promotes binding of apoA-I to the cell surface. About 10% of this bound apoA-I interacts directly with ABCA1 and stabilizes the transporter. Most of the pool of cell surface-associated apoA-I is bound to lipid domains in the PM that are created by the activity of ABCA1. The amphipathic α-helices in apoA-I confer detergent-like properties on the protein enabling it to solubilize PL and FC in these membrane domains to create a heterogeneous population of discoidal nascent HDL particles. This review focuses on current understanding of the structure-function relationships of human ABCA1 and the molecular mechanisms underlying HDL particle production.
Collapse
Affiliation(s)
- Michael C Phillips
- Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-5158
| |
Collapse
|
14
|
Fournier N, Sayet G, Vedie B, Nowak M, Allaoui F, Solgadi A, Caudron E, Chaminade P, Benoist JF, Paul JL. Eicosapentaenoic acid membrane incorporation impairs cholesterol efflux from cholesterol-loaded human macrophages by reducing the cholesteryl ester mobilization from lipid droplets. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1079-1091. [PMID: 28739279 DOI: 10.1016/j.bbalip.2017.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 12/26/2022]
Abstract
A diet containing a high n-3/n-6 polyunsaturated fatty acids (PUFA) ratio has cardioprotective properties. PUFAs incorporation into membranes influences the function of membrane proteins. We investigated the impact of the membrane incorporation of PUFAs, especially eicosapentaenoic acid (EPA) (C20:5 n-3), on the anti-atherogenic cholesterol efflux pathways. We used cholesteryl esters (CE)-loaded human monocyte-derived macrophages (HMDM) to mimic foam cells exposed to the FAs for a long period of time to ensure their incorporation into cellular membranes. Phospholipid fraction of EPA cells exhibited high levels of EPA and its elongation product docosapentaenoic acid (DPA) (C22:5 n-3), which was associated with a decreased level of arachidonic acid (AA) (C20:4 n-6). EPA 70μM reduced ABCA1-mediated cholesterol efflux to apolipoprotein (apo) AI by 30% without any alteration in ABCA1 expression. The other tested PUFAs, DPA, docosahexaenoic acid (DHA) (C22:6 n-3), and AA, were also able to reduce ABCA1 functionality while the monounsaturated oleic FA slightly decreased efflux and the saturated palmitic FA had no impact. Moreover, EPA also reduced cholesterol efflux to HDL mediated by the Cla-1 and ABCG1 pathways. EPA incorporation did not hinder efflux in free cholesterol-loaded HMDM and did not promote esterification of cholesterol. Conversely, EPA reduced the neutral hydrolysis of cytoplasmic CE by 24%. The reduced CE hydrolysis was likely attributed to the increase in cellular TG contents and/or the decrease in apo E secretion after EPA treatment. In conclusion, EPA membrane incorporation reduces cholesterol efflux in human foam cells by reducing the cholesteryl ester mobilization from lipid droplets.
Collapse
Affiliation(s)
- Natalie Fournier
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Athérosclérose: homéostasie et trafic du cholestérol des macrophages (FKA EA 4529), UFR de Pharmacie, 92296 Châtenay-Malabry, France; AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Européen Georges Pompidou, Laboratoire de Biochimie, 75015 Paris, France.
| | - Guillaume Sayet
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Chimie Analytique Pharmaceutique (FKA EA 4041), UFR de Pharmacie, 92296 Châtenay-Malabry, France
| | - Benoît Vedie
- AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Européen Georges Pompidou, Laboratoire de Biochimie, 75015 Paris, France
| | - Maxime Nowak
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Athérosclérose: homéostasie et trafic du cholestérol des macrophages (FKA EA 4529), UFR de Pharmacie, 92296 Châtenay-Malabry, France
| | - Fatima Allaoui
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Athérosclérose: homéostasie et trafic du cholestérol des macrophages (FKA EA 4529), UFR de Pharmacie, 92296 Châtenay-Malabry, France
| | - Audrey Solgadi
- Univ Paris Sud-Paris Saclay, SFR IPSIT (Institut Paris-Saclay d'Innovation Thérapeutique), UMS IPSIT Service d'Analyse des Médicaments et Métabolites, 92296 Châtenay-Malabry, France
| | - Eric Caudron
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Chimie Analytique Pharmaceutique (FKA EA 4041), UFR de Pharmacie, 92296 Châtenay-Malabry, France
| | - Pierre Chaminade
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Chimie Analytique Pharmaceutique (FKA EA 4041), UFR de Pharmacie, 92296 Châtenay-Malabry, France
| | - Jean-François Benoist
- AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Robert Debré, Laboratoire de Biochimie hormonale, 75019 Paris, France
| | - Jean-Louis Paul
- Univ Paris Sud-Paris Saclay, EA 7357, Lip(Sys)(2), Athérosclérose: homéostasie et trafic du cholestérol des macrophages (FKA EA 4529), UFR de Pharmacie, 92296 Châtenay-Malabry, France; AP-HP (Assistance Publique-Hôpitaux de Paris), Hôpital Européen Georges Pompidou, Laboratoire de Biochimie, 75015 Paris, France
| |
Collapse
|
15
|
Wallner S, Grandl M, Liebisch G, Peer M, Orsó E, Sigrüner A, Sobota A, Schmitz G. oxLDL and eLDL Induced Membrane Microdomains in Human Macrophages. PLoS One 2016; 11:e0166798. [PMID: 27870891 PMCID: PMC5117723 DOI: 10.1371/journal.pone.0166798] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/03/2016] [Indexed: 12/14/2022] Open
Abstract
Background Extravasation of macrophages and formation of lipid-laden foam cells are key events in the development and progression of atherosclerosis. The degradation of atherogenic lipoproteins subsequently leads to alterations in cellular lipid metabolism that influence inflammatory signaling. Especially sphingolipids and ceramides are known to be involved in these processes. We therefore analyzed monocyte derived macrophages during differentiation and after loading with enzymatically (eLDL) and oxidatively (oxLDL) modified low-density lipoproteins (LDL). Methods Primary human monocytes were isolated from healthy, normolipidemic blood donors using leukapheresis and counterflow elutriation. On the fourth day of MCSF-induced differentiation eLDL (40 μg/ml) or oxLDL (80 μg/ml) were added for 48h. Lipid species were analyzed by quantitative tandem mass spectrometry. Taqman qPCR was performed to investigate transcriptional changes in enzymes involved in sphingolipid metabolism. Furthermore, membrane lipids were studied using flow cytometry and confocal microscopy. Results MCSF dependent phagocytic differentiation of blood monocytes had only minor effects on the sphingolipid composition. Levels of total sphingomyelin and total ceramide remained unchanged, while lactosylceramides, cholesterylesters and free cholesterol decreased. At the species level most ceramide species showed a reduction upon phagocytic differentiation. Loading with eLDL preferentially increased cellular cholesterol while loading with oxLDL increased cellular ceramide content. Activation of the salvage pathway with a higher mRNA expression of acid and neutral sphingomyelinase, neutral sphingomyelinase activation associated factor and glucosylceramidase as well as increased surface expression of SMPD1 were identified as potentially underlying mechanisms. Moreover, flow-cytometric analysis revealed a higher cell-surface-expression of ceramide, lactosylceramide (CDw17), globotriaosylceramide (CD77), dodecasaccharide-ceramide (CD65s) and GM1 ganglioside upon oxLDL loading. ApoE in contrast to apoA-I preferentially bound to the ceramide enriched surfaces of oxLDL loaded cells. Confocal microscopy showed a co-localization of acid sphingomyelinase with ceramide rich membrane microdomains. Conclusion eLDL leads to the formation of lipid droplets and preferentially induces cholesterol/sphingomyelin rich membrane microdomains while oxLDL promotes the development of cholesterol/ceramide rich microdomains via activation of the salvage pathway.
Collapse
Affiliation(s)
- Stefan Wallner
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Margot Grandl
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Gerhard Liebisch
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Markus Peer
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Evelyn Orsó
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Alexander Sigrüner
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
| | - Andrzej Sobota
- Department of Cell Biology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Gerd Schmitz
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Regensburg, Germany
- * E-mail:
| |
Collapse
|
16
|
Eicosapentaenoic acid membrane incorporation impairs ABCA1-dependent cholesterol efflux via a protein kinase A signaling pathway in primary human macrophages. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:331-41. [DOI: 10.1016/j.bbalip.2016.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/04/2016] [Accepted: 01/07/2016] [Indexed: 11/22/2022]
|
17
|
Rodriguez-Cuenca S, Barbarroja N, Vidal-Puig A. Dihydroceramide desaturase 1, the gatekeeper of ceramide induced lipotoxicity. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:40-50. [DOI: 10.1016/j.bbalip.2014.09.021] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/25/2022]
|
18
|
Ihlefeld K, Vienken H, Claas RF, Blankenbach K, Rudowski A, ter Braak M, Koch A, Van Veldhoven PP, Pfeilschifter J, Meyer zu Heringdorf D. Upregulation of ABC transporters contributes to chemoresistance of sphingosine 1-phosphate lyase-deficient fibroblasts. J Lipid Res 2014; 56:60-9. [PMID: 25385827 DOI: 10.1194/jlr.m052761] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Sphingosine 1-phosphate (S1P) is an extra- and intracellular mediator that regulates cell growth, survival, migration, and adhesion in many cell types. S1P lyase is the enzyme that irreversibly cleaves S1P and thereby constitutes the ultimate step in sphingolipid catabolism. It has been reported previously that embryonic fibroblasts from S1P lyase-deficient mice (Sgpl1(-/-)-MEFs) are resistant to chemotherapy-induced apoptosis through upregulation of B cell lymphoma 2 (Bcl-2) and Bcl-2-like 1 (Bcl-xL). Here, we demonstrate that the transporter proteins Abcc1/MRP1, Abcb1/MDR1, Abca1, and spinster-2 are upregulated in Sgpl1(-/-)-MEFs. Furthermore, the cells efficiently sequestered the substrates of Abcc1 and Abcb1, fluo-4 and doxorubicin, in subcellular compartments. In line with this, Abcb1 was localized mainly at intracellular vesicular structures. After 16 h of incubation, wild-type MEFs had small apoptotic nuclei containing doxorubicin, whereas the nuclei of Sgpl1(-/-)-MEFs appeared unchanged and free of doxorubicin. A combined treatment with the inhibitors of Abcb1 and Abcc1, zosuquidar and MK571, respectively, reversed the compartmentalization of doxorubicin and rendered the cells sensitive to doxorubicin-induced apoptosis. It is concluded that upregulation of multidrug resistance transporters contributes to the chemoresistance of S1P lyase-deficient MEFs.
Collapse
Affiliation(s)
- Katja Ihlefeld
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Hans Vienken
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Ralf Frederik Claas
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Kira Blankenbach
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Agnes Rudowski
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Michael ter Braak
- Institut für Pharmakologie, Universitätsklinikum Essen, Essen, Germany
| | - Alexander Koch
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Paul P Van Veldhoven
- Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Josef Pfeilschifter
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| | - Dagmar Meyer zu Heringdorf
- Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe-Universität, Frankfurt am Main, Germany
| |
Collapse
|
19
|
Gulshan K, Smith J. Sphingomyelin regulation of plasma membrane asymmetry, efflux and reverse cholesterol transport. ACTA ACUST UNITED AC 2014. [DOI: 10.2217/clp.14.28] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
20
|
Martins IJ, Creegan R. Links between Insulin Resistance, Lipoprotein Metabolism and Amyloidosis in Alzheimer’s Disease. Health (London) 2014. [DOI: 10.4236/health.2014.612190] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
21
|
Liu M, Seo J, Allegood J, Bi X, Zhu X, Boudyguina E, Gebre AK, Avni D, Shah D, Sorci-Thomas MG, Thomas MJ, Shelness GS, Spiegel S, Parks JS. Hepatic apolipoprotein M (apoM) overexpression stimulates formation of larger apoM/sphingosine 1-phosphate-enriched plasma high density lipoprotein. J Biol Chem 2013; 289:2801-14. [PMID: 24318881 DOI: 10.1074/jbc.m113.499913] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Apolipoprotein M (apoM), a lipocalin family member, preferentially associates with plasma HDL and binds plasma sphingosine 1-phosphate (S1P), a signaling molecule active in immune homeostasis and endothelial barrier function. ApoM overexpression in ABCA1-expressing HEK293 cells stimulated larger nascent HDL formation, compared with cells that did not express apoM; however, the in vivo role of apoM in HDL metabolism remains poorly understood. To test whether hepatic apoM overexpression increases plasma HDL size, we generated hepatocyte-specific apoM transgenic (APOM Tg) mice, which had an ∼3-5-fold increase in plasma apoM levels compared with wild-type mice. Although HDL cholesterol concentrations were similar to wild-type mice, APOM Tg mice had larger plasma HDLs enriched in apoM, cholesteryl ester, lecithin:cholesterol acyltransferase, and S1P. Despite the presence of larger plasma HDLs in APOM Tg mice, in vivo macrophage reverse cholesterol transport capacity was similar to that in wild-type mice. APOM Tg mice had an ∼5-fold increase in plasma S1P, which was predominantly associated with larger plasma HDLs. Primary hepatocytes from APOM Tg mice generated larger nascent HDLs and displayed increased sphingolipid synthesis and S1P secretion. Inhibition of ceramide synthases in hepatocytes increased cellular S1P levels but not S1P secretion, suggesting that apoM is rate-limiting in the export of hepatocyte S1P. Our data indicate that hepatocyte-specific apoM overexpression generates larger nascent HDLs and larger plasma HDLs, which preferentially bind apoM and S1P, and stimulates S1P biosynthesis for secretion. The unique apoM/S1P-enriched plasma HDL may serve to deliver S1P to extrahepatic tissues for atheroprotection and may have other as yet unidentified functions.
Collapse
Affiliation(s)
- Mingxia Liu
- From the Departments of Pathology-Lipid Sciences and
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
The apolipoprotein m-sphingosine-1-phosphate axis: biological relevance in lipoprotein metabolism, lipid disorders and atherosclerosis. Int J Mol Sci 2013; 14:4419-31. [PMID: 23439550 PMCID: PMC3634416 DOI: 10.3390/ijms14034419] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/17/2013] [Accepted: 02/05/2013] [Indexed: 01/27/2023] Open
Abstract
Apolipoprotein M (apoM) is a plasma apolipoprotein that mainly associates with high-density lipoproteins. Hence, most studies on apoM so far have investigated its effect on and association with lipid metabolism and atherosclerosis. The insight into apoM biology recently took a major turn. ApoM was identified as a carrier of the bioactive lipid sphingosine-1-phosphate (S1P). S1P activates five different G-protein-coupled receptors, known as the S1P-receptors 1–5 and, hence, affects a wide range of biological processes, such as lymphocyte trafficking, angiogenesis, wound repair and even virus suppression and cancer. The ability of apoM to bind S1P is due to a lipophilic binding pocket within the lipocalin structure of the apoM molecule. Mice overexpressing apoM have increased plasma S1P concentrations, whereas apoM-deficient mice have decreased S1P levels. ApoM-S1P is able to activate the S1P-receptor-1, affecting the function of endothelial cells, and apoM-deficient mice display impaired endothelial permeability in the lung. This review will focus on the putative biological roles of the new apoM–S1P axis in relation to lipoprotein metabolism, lipid disorders and atherosclerosis.
Collapse
|
23
|
Huang CX, Zhang YL, Wang JF, Jiang JY, Bao JL. MCP-1 impacts RCT by repressing ABCA1, ABCG1, and SR-BI through PI3K/Akt posttranslational regulation in HepG2 cells. J Lipid Res 2013; 54:1231-40. [PMID: 23402987 DOI: 10.1194/jlr.m032482] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monocyte chemoattractant protein-1 (MCP-1) plays crucial roles at multiple stages of atherosclerosis. We hypothesized that MCP-1 might impair the reverse cholesterol transport (RCT) capacity of HepG2 cells by decreasing the cell-surface protein expression of ATP binding cassette A1 (ABCA1), ATP binding cassette G1 (ABCG1), and scavenger receptor class B type I (SR-BI). MCP-1 reduced the total protein and mRNA levels of ABCA1 and SR-BI, but not of ABCG1. MCP-1 decreased the cell-surface protein expression of ABCA1, ABCG1, and SR-BI in dose-dependent and time-dependent manners, as measured using cell-surface biotinylation. We further studied the phosphoinositide 3-kinase (PI3K)/serine/threonine protein kinase Akt pathway in regulating receptor trafficking. Both the translation and transcription of ABCA1, ABCG1, and SR-BI were not found to be regulated by the PI3K/Akt pathway. However, the cell-surface protein expression of ABCA1, ABCG1, and SR-BI could be regulated by PI3K activity, and PI3K activation corrected the MCP-1-induced decreases in the cell-surface protein expression of ABCA1, ABCG1, and SR-BI. Moreover, we found that MCP-1 decreased the lipid uptake by HepG2 cells and the ABCA1-mediated cholesterol efflux to apoA-I, which could be reversed by PI3K activation. Our data suggest that MCP-1 impairs RCT activity in HepG2 cells by a PI3K/Akt-mediated posttranslational regulation of ABCA1, ABCG1, and SR-BI cell-surface expression.
Collapse
Affiliation(s)
- Can-Xia Huang
- Department of Cardiology, Sun Yat-sen Memorial Hospital, University of Sun Yat-sen, Guangzhou, China
| | | | | | | | | |
Collapse
|
24
|
Breen EC, Malloy JL, Tang K, Xia F, Fu Z, Hancock REW, Overhage J, Wagner PD, Spragg RG. Impaired pulmonary defense against Pseudomonas aeruginosa in VEGF gene inactivated mouse lung. J Cell Physiol 2013; 228:371-9. [PMID: 22718316 DOI: 10.1002/jcp.24140] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Repeated bacterial and viral infections are known to contribute to worsening lung function in several respiratory diseases, including asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD). Previous studies have reported alveolar wall cell apoptosis and parenchymal damage in adult pulmonary VEGF gene ablated mice. We hypothesized that VEGF expressed by type II cells is also necessary to provide an effective host defense against bacteria in part by maintaining surfactant homeostasis. Therefore, Pseudomonas aeruginosa (PAO1) levels were evaluated in mice following lung-targeted VEGF gene inactivation, and alterations in VEGF-dependent type II cell function were evaluated by measuring surfactant homeostasis in mouse lungs and isolated type II cells. In VEGF-deficient lungs increased PAO1 levels and pro-inflammatory cytokines, TNFα and IL-6, were detected 24 h after bacterial instillation compared to control lungs. In vivo lung-targeted VEGF gene deletion (57% decrease in total pulmonary VEGF) did not alter alveolar surfactant or tissue disaturated phosphatidylcholine (DSPC) levels. However, sphingomyelin content, choline phosphate cytidylyltransferase (CCT) mRNA, and SP-D expression were decreased. In isolated type II cells an 80% reduction of VEGF protein resulted in decreases in total phospholipids (PL), DSPC, DSPC synthesis, surfactant associated proteins (SP)-B and -D, and the lipid transporters, ABCA1 and Rab3D. TPA-induced DSPC secretion and apoptosis were elevated in VEGF-deficient type II cells. These results suggest a potential protective role for type II cell-expressed VEGF against bacterial initiated infection.
Collapse
Affiliation(s)
- Ellen C Breen
- Division of Physiology, Department of Medicine, University of California, San Diego, La Jolla, California 92093-0623, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Kim YM, Park TS, Kim SG. The role of sphingolipids in drug metabolism and transport. Expert Opin Drug Metab Toxicol 2013; 9:319-31. [PMID: 23289866 DOI: 10.1517/17425255.2013.748749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Sphingolipids represent a diverse class of lipid molecules. In addition to their function as membrane structural components, they serve as signaling molecules involved in various biological processes such as cell metabolism, growth, differentiation, stress and inflammatory responses and apoptosis. Sphingolipids may modulate the activity and/or expression of cytochrome P450s (CYPs) and transporters, which suggests that they may affect drug metabolism and excretion. AREAS COVERED In this review, the authors provide an overview of the properties of sphingolipid structures and metabolism. They also describe the effects of sphingolipids on the activity and expression of CYPs and transporters. In addition, the authors discuss the pathologic conditions where the sphingolipid metabolism is dysregulated particularly in association with inflammation and cancer. EXPERT OPINION Sphingolipidomic approaches have become accessible with the aid of advances in analytical technology. Sphingolipid profiles are modified by diseases, genetic disorders or certain drug treatment. The consequent changes in sphingolipid contents may alter the activities of detoxifying enzymes and those associated with cell viability. Since CYPs and transporters play roles in xenobiotics metabolism and excretion, sphingolipidomic information may be of use in understanding drug effect and toxicity.
Collapse
Affiliation(s)
- Young Mi Kim
- Seoul National University, Research Institute of Pharmaceutical Sciences, College of Pharmacy, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-742, Korea
| | | | | |
Collapse
|
26
|
Lin S, Zhou C, Neufeld E, Wang YH, Xu SW, Lu L, Wang Y, Liu ZP, Li D, Li C, Chen S, Le K, Huang H, Liu P, Moss J, Vaughan M, Shen X. BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein modulates ATP-binding cassette transporter A-1 trafficking and function. Arterioscler Thromb Vasc Biol 2012; 33:e31-8. [PMID: 23220274 DOI: 10.1161/atvbaha.112.300720] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Cell-surface localization and intracellular trafficking are essential for the function of ATP-binding cassette transporter A-1 (ABCA1). However, regulation of these activities is still largely unknown. Brefeldin A, an uncompetitive inhibitor of brefeldin A-inhibited guanine nucleotide-exchange proteins (BIGs), disturbs the intracellular distribution of ABCA1, and thus inhibits cholesterol efflux. This study aimed to define the possible roles of BIGs in regulating ABCA1 trafficking and cholesterol efflux, and further to explore the potential mechanism. METHODS AND RESULTS By vesicle immunoprecipitation, we found that BIG1 was associated with ABCA1 in vesicles preparation from rat liver. BIG1 depletion reduced surface ABCA1 on HepG2 cells, and inhibited by 60% cholesterol release. In contrast, BIG1 overexpression increased surface ABCA1 and cholesterol secretion. With partial restoration of BIG1 through overexpression in BIG1-depleted cells, surface ABCA1 was also restored. Biotinylation and glutathione cleavage revealed that BIG1 small interfering RNA dramatically decreased the internalization and recycling of ABCA1. This novel function of BIG1 was dependent on the guanine nucleotide-exchange activity and achieved through activation of ADP-ribosylation factor 1. CONCLUSIONS BIG1, through its ability to activate ADP-ribosylation factor 1, regulates cell-surface levels and function of ABCA1, indicating a transcription-independent mechanism for controlling ABCA1 action.
Collapse
Affiliation(s)
- Sisi Lin
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, No. 132, East Wai-Huan Rd, College Town, Guangzhou 510006, PR China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Coleman JA, Quazi F, Molday RS. Mammalian P4-ATPases and ABC transporters and their role in phospholipid transport. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1831:555-74. [PMID: 23103747 DOI: 10.1016/j.bbalip.2012.10.006] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/16/2012] [Accepted: 10/18/2012] [Indexed: 02/08/2023]
Abstract
Transport of phospholipids across cell membranes plays a key role in a wide variety of biological processes. These include membrane biosynthesis, generation and maintenance of membrane asymmetry, cell and organelle shape determination, phagocytosis, vesicle trafficking, blood coagulation, lipid homeostasis, regulation of membrane protein function, apoptosis, etc. P(4)-ATPases and ATP binding cassette (ABC) transporters are the two principal classes of membrane proteins that actively transport phospholipids across cellular membranes. P(4)-ATPases utilize the energy from ATP hydrolysis to flip aminophospholipids from the exocytoplasmic (extracellular/lumen) to the cytoplasmic leaflet of cell membranes generating membrane lipid asymmetry and lipid imbalance which can induce membrane curvature. Many ABC transporters play crucial roles in lipid homeostasis by actively transporting phospholipids from the cytoplasmic to the exocytoplasmic leaflet of cell membranes or exporting phospholipids to protein acceptors or micelles. Recent studies indicate that some ABC proteins can also transport phospholipids in the opposite direction. The importance of P(4)-ATPases and ABC transporters is evident from the findings that mutations in many of these transporters are responsible for severe human genetic diseases linked to defective phospholipid transport. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
Collapse
Affiliation(s)
- Jonathan A Coleman
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| | | | | |
Collapse
|
28
|
Liu J, Zhang Z, Xu Y, Feng T, Jiang W, Li Z, Hong B, Xie Z, Si S. IMB2026791, a xanthone, stimulates cholesterol efflux by increasing the binding of apolipoprotein A-I to ATP-binding cassette transporter A1. Molecules 2012; 17:2833-54. [PMID: 22399138 PMCID: PMC6268880 DOI: 10.3390/molecules17032833] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/16/2012] [Accepted: 02/24/2012] [Indexed: 11/24/2022] Open
Abstract
It is known that the ATP-binding cassette transporter A1 (ABCA1) plays a major role in cholesterol homeostasis and high density lipoprotein (HDL) metabolism. Several laboratories have demonstrated that ABCA1 binding to lipid-poor apolipoprotein A-I (apoA-I) will mediate the assembly of nascent HDL and cellular cholesterol efflux, which suggests a possible receptor-ligand interaction between ABCA1 and apoA-I. In this study, a cell-based-ELISA-like high-throughput screening (HTS) method was developed to identify the synthetic and natural compounds that can regulate binding activity of ABCA1 to apoA-I. The cell-based-ELISA-like high-throughput screen was conducted in a 96-well format using Chinese hamster ovary (CHO) cells stably transfected with ABCA1 pIRE2-EGFP (Enhanced Green Fluorecence Protein) expression vector and the known ABCA1 inhibitor glibenclamide as the antagonist control. From 2,600 compounds, a xanthone compound (IMB 2026791) was selected using this HTS assay, and it was proved as an apoA-I binding agonist to ABCA1 by a flow cytometry assay and western blot analysis. The 3H cholesterol efflux assay of IMB2026791 treated ABCA1-CHO cells and PMA induced THP-1 macrophages (human acute monocytic leukemia cell) further confirmed the compound as an accelerator of cholesterol efflux in a dose-dependent manner with an EC50 of 25.23 μM.
Collapse
Affiliation(s)
- Jikai Liu
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Zhongbing Zhang
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Yanni Xu
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Tingting Feng
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Wei Jiang
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Zhuorong Li
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Bin Hong
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
| | - Zijian Xie
- Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, OH 43614, USA
- Authors to whom correspondence should be addressed; (Z.X.); (S.S.); Tel.: +1-419-383-4182 (Z.X.); Fax: +1-419-383-2871 (Z.X.); Tel./Fax: +86-10-6318-0604 (S.S.)
| | - Shuyi Si
- China Institute of Medical Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tiantanxili #1, Beijing 100050, China; (J.L.); (Z.Z.); (Y.X.); (T.F.); (W.J.); (Z.L.); (B.H.)
- Authors to whom correspondence should be addressed; (Z.X.); (S.S.); Tel.: +1-419-383-4182 (Z.X.); Fax: +1-419-383-2871 (Z.X.); Tel./Fax: +86-10-6318-0604 (S.S.)
| |
Collapse
|
29
|
Le Lay S, Rodriguez M, Jessup W, Rentero C, Li Q, Cartland S, Grewal T, Gaus K. Caveolin-1-mediated apolipoprotein A-I membrane binding sites are not required for cholesterol efflux. PLoS One 2011; 6:e23353. [PMID: 21858084 PMCID: PMC3155548 DOI: 10.1371/journal.pone.0023353] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/13/2011] [Indexed: 11/18/2022] Open
Abstract
Caveolin-1 (Cav1), a structural protein required for the formation of invaginated membrane domains known as caveolae, has been implicated in cholesterol trafficking and homeostasis. Here we investigated the contribution of Cav1 to apolipoprotein A-I (apoA-I) cell surface binding and intracellular processing using mouse embryonic fibroblasts (MEFs) derived from wild type (WT) or Cav1-deficient (Cav1(-/-)) animals. We found that cells expressing Cav1 have 2.6-fold more apoA-I binding sites than Cav1(-/-) cells although these additional binding sites are not associated with detergent-free lipid rafts. Further, Cav1-mediated binding targets apoA-I for internalization and degradation and these processes are not correlated to cholesterol efflux. Despite lower apoA-I binding, cholesterol efflux from Cav1(-/-) MEFs is 1.7-fold higher than from WT MEFs. Stimulation of ABCA1 expression with an LXR agonist enhances cholesterol efflux from both WT and Cav1(-/-) cells without increasing apoA-I surface binding or affecting apoA-I processing. Our results indicate that there are at least two independent lipid binding sites for apoA-I; Cav1-mediated apoA-I surface binding and uptake is not linked to cholesterol efflux, indicating that membrane domains other than caveolae regulate ABCA1-mediated cholesterol efflux.
Collapse
Affiliation(s)
- Soazig Le Lay
- Centre de Recherche des Cordeliers, INSERM, U872, Paris, France
| | - Macarena Rodriguez
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Wendy Jessup
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Carles Rentero
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Qiong Li
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Siân Cartland
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
| | - Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, Australia
| | - Katharina Gaus
- Centre for Vascular Research, University of New South Wales, Sydney, Australia
- * E-mail:
| |
Collapse
|
30
|
Basford JE, Wancata L, Hofmann SM, Silva RAGD, Davidson WS, Howles PN, Hui DY. Hepatic deficiency of low density lipoprotein receptor-related protein-1 reduces high density lipoprotein secretion and plasma levels in mice. J Biol Chem 2011; 286:13079-87. [PMID: 21343303 DOI: 10.1074/jbc.m111.229369] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The low density lipoprotein receptor-related protein-1 (LRP1) is known to serve as a chylomicron remnant receptor in the liver responsible for the binding and plasma clearance of apolipoprotein E-containing lipoproteins. Previous in vitro studies have provided evidence to suggest that LRP1 expression may also influence high density lipoprotein (HDL) metabolism. The current study showed that liver-specific LRP1 knock-out (hLrp1(-/-)) mice displayed lower fasting plasma HDL cholesterol levels when compared with hLrp1(+/+) mice. Lecithin:cholesterol acyl transferase and hepatic lipase activities in plasma of hLrp1(-/-) mice were comparable with those observed in hLrp1(+/+) mice, indicating that hepatic LRP1 inactivation does not influence plasma HDL remodeling. Plasma clearance of HDL particles and HDL-associated cholesteryl esters was also similar between hLrp1(+/+) and hLrp1(-/-) mice. In contrast, HDL secretion from primary hepatocytes isolated from hLrp1(-/-) mice was significantly reduced when compared with that observed with hLrp1(+/+) hepatocytes. Biotinylation of cell surface proteins revealed decreased surface localization of the ATP-binding cassette, subfamily A, member 1 (ABCA1) protein, but total cellular ABCA1 level was not changed in hLrp1(-/-) hepatocytes. Finally, hLrp1(-/-) hepatocytes displayed reduced binding capacity for extracellular cathepsin D, resulting in lower intracellular cathepsin D content and impairment of prosaposin activation, a process that is required for membrane translocation of ABCA1 to facilitate cholesterol efflux and HDL secretion. Taken together, these results documented that hepatic LRP1 participates in cellular activation of lysosomal enzymes and through this mechanism, indirectly modulates the production and plasma levels of HDL.
Collapse
Affiliation(s)
- Joshua E Basford
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati College of Medicine, Cincinnati, Ohio 45237, USA
| | | | | | | | | | | | | |
Collapse
|
31
|
Worgall TS. Sphingolipid Synthetic Pathways are Major Regulators of Lipid Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 721:139-48. [DOI: 10.1007/978-1-4614-0650-1_9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
32
|
Abstract
Cholesterol-engorged macrophage foam cells are a critical component of the atherosclerotic lesion. Reducing the sterol deposits in lesions reduces clinical events. Sterol accumulations within lysosomes have proven to be particularly hard to mobilize out of foam cells. Moreover, excess sterol accumulation in lysosomes has untoward effects, including a complete disruption of lysosome function. Recently, we demonstrated that treatment of sterol-engorged macrophages in culture with triglyceride-containing particles can reverse many of the effects of cholesterol on lysosomes and dramatically reduce the sterol burden in these cells. This article describes what is known about lysosomal sterol engorgement, discusses the possible mechanisms by which triglyceride could produce its effects, and evaluates the possible positive and negative effects of reducing the lysosomal cholesterol levels in foam cells.
Collapse
Affiliation(s)
- W Gray Jerome
- Department of Pathology, U-2206 Medical Center North Vanderbilt University School of Medicine 1161 21st Avenue, South Nashville, TN 37232-32561, USA, Tel.: +1 615 322 5530
| |
Collapse
|
33
|
Jazwinski SM, Kim S, Dai J, Li L, Bi X, Jiang JC, Arnold J, Batzer MA, Walker JA, Welsh DA, Lefante CM, Volaufova J, Myers L, Su LJ, Hausman DB, Miceli MV, Ravussin E, Poon LW, Cherry KE, Welsch MA. HRAS1 and LASS1 with APOE are associated with human longevity and healthy aging. Aging Cell 2010; 9:698-708. [PMID: 20569235 DOI: 10.1111/j.1474-9726.2010.00600.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The search for longevity-determining genes in human has largely neglected the operation of genetic interactions. We have identified a novel combination of common variants of three genes that has a marked association with human lifespan and healthy aging. Subjects were recruited and stratified according to their genetically inferred ethnic affiliation to account for population structure. Haplotype analysis was performed in three candidate genes, and the haplotype combinations were tested for association with exceptional longevity. An HRAS1 haplotype enhanced the effect of an APOE haplotype on exceptional survival, and a LASS1 haplotype further augmented its magnitude. These results were replicated in a second population. A profile of healthy aging was developed using a deficit accumulation index, which showed that this combination of gene variants is associated with healthy aging. The variation in LASS1 is functional, causing enhanced expression of the gene, and it contributes to healthy aging and greater survival in the tenth decade of life. Thus, rare gene variants need not be invoked to explain complex traits such as aging; instead rare congruence of common gene variants readily fulfills this role. The interaction between the three genes described here suggests new models for cellular and molecular mechanisms underlying exceptional survival and healthy aging that involve lipotoxicity.
Collapse
Affiliation(s)
- S Michal Jazwinski
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Lee BJ, Kim JS, Kim BK, Jung SJ, Joo MK, Hong SG, Kim JS, Kim JH, Yeon JE, Park JJ, Byun KS, Bak YT, Yoo HS, Oh S. Effects of sphingolipid synthesis inhibition on cholesterol gallstone formation in C57BL/6J mice. J Gastroenterol Hepatol 2010; 25:1105-10. [PMID: 20594226 DOI: 10.1111/j.1440-1746.2010.06246.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND Sphingolipids play a very important role in cell membrane formation, signal transduction and plasma lipoprotein metabolism. The first rate-limiting step in the sphingolipid biosynthetic pathway is catalyzed by serine palmitoyltransferase (SPT), and myriocin is a potent and specific inhibitor of SPT. We investigated the impact of SPT inhibition on cholesterol gallstone formation in C57BL/6J mice. METHODS Three groups of eight-week-old C57BL/6J mice were utilized. Each group consisted of 20 mice; group A, B, and C were fed normal chow, lithogenic diet with phosphate buffered saline, and lithogenic diet with myriocin (0.3 mg/kg), respectively, for 6 weeks. The ceramide levels in both serum and bile were assessed by high performance liquid chromatography analysis. Protein expression of ERK, JNK and p38 in the extracted gallbladder were determined by Western-blot analysis. RESULTS Myriocin treatment caused a significant decrease in the rate of cholesterol gallstone formation. The lithogenic diet mice (group B) showed the highest ceramide activities in both the serum and bile among all the tested groups and there was significant suppression of the ceramide levels in both the serum and bile of the myriocin-treated mice (group C, p < 0.05). Phosphorylation of p38 in the gallbladder was increased in the lithogenic-diet mice and the expression of phosphorylated p38 was significantly suppressed in the myriocin treated mice. CONCLUSIONS SPT inhibition by myriocin suppressed gallstone formation and the levels of ceramide in both the serum and bile. p38 in the cellular signaling pathways might be associated with cholesterol gallstone formation.
Collapse
Affiliation(s)
- Beom Jae Lee
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Kuver R. Bioactive sphingolipids in the biliary tract: relevance for cholesterol gallstone disease. J Gastroenterol Hepatol 2010; 25:1020-3. [PMID: 20594212 DOI: 10.1111/j.1440-1746.2010.06321.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
|
36
|
|
37
|
Abstract
There is renewed interest in high-density lipoproteins (HDLs) due to recent findings linking atherosclerosis to the formation of dysfunctional HDL. This article focuses on the universe of HDL lipids and their potential protective or proinflammatory roles in vascular disease and insulin resistance. HDL carries a wide array of lipids including sterols, triglycerides, fat-soluble vitamins, and a large number of phospholipids, including phosphatidylcholine, sphingomyelin, and ceramide with many biological functions. Ceramide has been implicated in the pathogenesis of insulin resistance and has many proinflammatory properties. In contrast, sphingosine-1-phosphate, which is transported mainly in HDL, has anti-inflammatory properties that may be atheroprotective and may account for some of the beneficial effects of HDL. However, the complexity of the HDL lipidome is only beginning to reveal itself. The emergence of new analytical technologies should rapidly increase our understanding of the function of HDL lipids and their role in disease states.
Collapse
Affiliation(s)
- Andrew N Hoofnagle
- Department of Laboratory Medicine, University of Washington School of Medicine, Mailstop 358055, 815 Mercer Street, Seattle, WA 98109, USA
| | | | | | | |
Collapse
|
38
|
Bektas M, Allende ML, Lee BG, Chen W, Amar MJ, Remaley AT, Saba JD, Proia RL. Sphingosine 1-phosphate lyase deficiency disrupts lipid homeostasis in liver. J Biol Chem 2010; 285:10880-9. [PMID: 20097939 DOI: 10.1074/jbc.m109.081489] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cleavage of sphingoid base phosphates by sphingosine-1-phosphate (S1P) lyase to produce phosphoethanolamine and a fatty aldehyde is the final degradative step in the sphingolipid metabolic pathway. We have studied mice with an inactive S1P lyase gene and have found that, in addition to the expected increase of sphingoid base phosphates, other sphingolipids (including sphingosine, ceramide, and sphingomyelin) were substantially elevated in the serum and/or liver of these mice. This latter increase is consistent with a reutilization of the sphingosine backbone for sphingolipid synthesis due to its inability to exit the sphingolipid metabolic pathway. Furthermore, the S1P lyase deficiency resulted in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol. Even though lipids in serum and lipid storage were elevated in liver, adiposity was reduced in the S1P lyase-deficient mice. Microarray analysis of lipid metabolism genes in liver showed that the S1P lyase deficiency caused widespread changes in their expression pattern, with a significant increase in the expression of PPARgamma, a master transcriptional regulator of lipid metabolism. However, the mRNA expression of the genes encoding the sphingosine kinases and S1P phosphatases, which directly control the levels of S1P, were not significantly changed in liver of the S1P lyase-deficient mice. These results demonstrate that S1P lyase is a key regulator of the levels of multiple sphingolipid substrates and reveal functional links between the sphingolipid metabolic pathway and other lipid metabolic pathways that may be mediated by shared lipid substrates and changes in gene expression programs. The disturbance of lipid homeostasis by altered sphingolipid levels may be relevant to metabolic diseases.
Collapse
Affiliation(s)
- Meryem Bektas
- Genetics of Development and Disease Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Klappe K, Hummel I, Hoekstra D, Kok JW. Lipid dependence of ABC transporter localization and function. Chem Phys Lipids 2009; 161:57-64. [PMID: 19651114 DOI: 10.1016/j.chemphyslip.2009.07.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/24/2009] [Accepted: 07/24/2009] [Indexed: 02/06/2023]
Abstract
Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. ATP-binding cassette (ABC) transporters have also been localized in these membrane domains. In this review the evidence for this specific localization will be evaluated and discussed in terms of relevance to ABC transporter function. We will focus on three ABC transporters of the A, B and C subfamily, respectively. Two of these transporters are relevant to multidrug resistance in tumor cells (Pgp/ABCB1 and MRP1/ABCC1), while the third (ABCA1) is extensively studied in relation to the reverse cholesterol pathway and cellular cholesterol homeostasis. We will attempt to derive a generalized model of lipid rafts to which they associate based on the use of various different lipid raft isolation procedures. In the context of lipid rafts, modulation of ABC transporter localization and function by two relevant lipid classes, i.e. sphingolipids and cholesterol, will be discussed.
Collapse
Affiliation(s)
- Karin Klappe
- Department of Cell Biology, Section Membrane Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | | | | | | |
Collapse
|
40
|
Singaraja RR, Kang MH, Vaid K, Sanders SS, Vilas GL, Arstikaitis P, Coutinho J, Drisdel RC, El-Husseini AED, Green WN, Berthiaume L, Hayden MR. Palmitoylation of ATP-Binding Cassette Transporter A1 Is Essential for Its Trafficking and Function. Circ Res 2009; 105:138-47. [DOI: 10.1161/circresaha.108.193011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Roshni R. Singaraja
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Martin H. Kang
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Kuljeet Vaid
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Shaun S. Sanders
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Gonzalo L. Vilas
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Pamela Arstikaitis
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Jonathan Coutinho
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Renaldo C. Drisdel
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Alaa El Din El-Husseini
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - William N. Green
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Luc Berthiaume
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| | - Michael R. Hayden
- From the Centre for Molecular Medicine and Therapeutics (R.R.S., M.H.K., K.V., S.S.S., J.C., M.R.H.) and Department of Psychiatry (P.A., A.E.D.E.-H.), University of British Columbia, Vancouver, Canada; Department of Cell Biology (G.L.V., L.B.), University of Alberta, Edmonton, Canada; and Department of Neurobiology, Pharmacology and Physiology (R.C.D., W.N.G.), University of Chicago, Ill
| |
Collapse
|
41
|
Transport of lipids by ABC proteins: interactions and implications for cellular toxicity, viability and function. Chem Biol Interact 2009; 180:327-39. [PMID: 19426719 DOI: 10.1016/j.cbi.2009.04.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 04/15/2009] [Accepted: 04/24/2009] [Indexed: 12/16/2022]
Abstract
Members of the ATP-binding cassette (ABC) family of membrane-bound transporters are involved in multiple aspects of transport and redistribution of various lipids and their conjugates. Most ABC transporters localize to the plasma membrane; some are associated with liquid-ordered cholesterol-/sphingolipid-rich microdomains, and to a lesser extent the membranes of the Golgi and endoplasmic reticulum. Hence, ABC transporters are well placed to regulate plasma membrane lipid composition and the efflux and redistribution of structural phospholipids and sphingolipids during periods of cellular stress and recovery. ABC transporters can also modulate cellular sensitivity to extrinsic pro-apoptotic signals through regulation of sphingomyelin-ceramide biosynthesis and metabolism. The functionality of ABC transporters is, in turn, modulated by the lipid content of the microdomains in which they reside. Cholesterol, a major membrane microdomain component, is not only a substrate of several ABC transporters, but also regulates ABC activity through its effects on microdomain structure. Several important bioactive lipid mediators and toxic lipid metabolites are also effluxed by ABC transporters. In this review, the complex interactions between ABC transporters and their lipid/sterol substrates will be discussed and analyzed in the context of their relevance to cellular function, toxicity and apoptosis.
Collapse
|
42
|
Li Z, Park TS, Li Y, Pan X, Iqbal J, Lu D, Tang W, Yu L, Goldberg IJ, Hussain MM, Jiang XC. Serine palmitoyltransferase (SPT) deficient mice absorb less cholesterol. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:297-306. [PMID: 19416652 DOI: 10.1016/j.bbalip.2009.01.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Revised: 12/24/2008] [Accepted: 01/15/2009] [Indexed: 11/30/2022]
Abstract
Serine palmitoyltransferase (SPT) is the key enzyme for the biosynthesis of sphingolipids. It has been reported that oral administration of myriocin (an SPT inhibitor) decreases plasma sphingomyelin (SM) and cholesterol levels, and reduces atherosclerosis in apoE knockout (KO) mice. We studied cholesterol absorption in myriocin-treated WT or apoE KO animals and found that, after myriocin treatment, the mice absorbed significantly less cholesterol than controls, with no observable pathological changes in the small intestine. More importantly, we found that heterozygous Sptlc1 (a subunit of SPT) KO mice also absorbed significantly less cholesterol than controls. To understand the mechanism, we measured protein levels of Niemann-Pick C1-like 1 (NPC1L1), ABCG5, and ABCA1, three key factors involved in intestinal cholesterol absorption. We found that NPC1L1 and ABCA1 were decreased, whereas ABCG5 was increased in the SPT deficient small intestine. SM levels on the apical membrane were also measured and they were significantly decreased in SPT deficient mice, compared with controls. In conclusion, SPT deficiency might reduce intestinal cholesterol absorption by altering NPC1L1 and ABCG5 protein levels in the apical membranes of enterocytes through lowering apical membrane SM levels. This may be also true for ABCA1 which locates on basal membrane of enterocytes. Manipulation of SPT activity could thus provide a novel alternative treatment for dyslipidemia.
Collapse
Affiliation(s)
- Zhiqiang Li
- Department of Anatomy and Cell Biology, State University of New York Downstate Medical Center, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Qiu G, Hill JS. Endothelial lipase promotes apolipoprotein AI-mediated cholesterol efflux in THP-1 macrophages. Arterioscler Thromb Vasc Biol 2008; 29:84-91. [PMID: 18988890 DOI: 10.1161/atvbaha.108.176487] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Endothelial lipase (EL) is expressed by macrophages within atherosclerotic lesions. We investigated the influence of EL expression on cholesterol efflux in macrophages. METHODS AND RESULTS The present study used lentivirus to introduce either EL shRNA for loss-of-function studies or EL cDNA for gain-of-function studies to investigate the role of EL in apoAI-mediated cholesterol efflux. ApoAI-mediated cholesterol efflux was decreased after EL suppression, but increased with EL overexpression in free cholesterol labeled and acLDL loaded THP-1 macrophages. Similar findings were observed in THP-1 macrophages after exogenous EL addition and in transfected 293 cells. EL-related apoAI-mediated cholesterol efflux decreased after treatment with heparin or catalytic inactivation (S149A mutation or tetrahydrolipstatin) alone, and completely inhibited in combination. Furthermore, EL expression did not change ABCA1 expression, but was positively correlated with apoAI binding to macrophages and 293 cells. This effect was mitigated after heparin treatment but not influenced by catalytic inactivation via tetrahydrolipstatin or the S149A mutation. Moreover, EL expression was positively associated with lysophosphatidylcholine production and inversely with phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin levels. Lysophosphatidylcholine treatment dose-dependently stimulated apoAI-mediated cholesterol efflux in THP-1 macrophages. CONCLUSIONS EL appears to promote apoAI-mediated cholesterol efflux through catalytic and noncatalytic-dependent mechanisms.
Collapse
Affiliation(s)
- Guosong Qiu
- James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Providence Heart+Lung Institute, Department of Pathology and Laboratory Medicine, University of British Columbia-St. Paul's Hospital, Vancouver, BC Canada
| | | |
Collapse
|
44
|
Lu R, Arakawa R, Ito-Osumi C, Iwamoto N, Yokoyama S. ApoA-I facilitates ABCA1 recycle/accumulation to cell surface by inhibiting its intracellular degradation and increases HDL generation. Arterioscler Thromb Vasc Biol 2008; 28:1820-4. [PMID: 18617649 DOI: 10.1161/atvbaha.108.169482] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Calpain-mediated proteolysis is one of the major regulatory factors for activity of ATP-binding cassette transporter (ABC) A1. Helical apolipoproteins protect ABCA1 against this degradation and increase generation of HDL. We investigated the mechanism for this reaction focusing on roles of endocytotic internalization of ABCA1. METHODS AND RESULTS Surface ABCA1 was labeled with biotin and traced for its internalization and degradation. ABCA1 in the cell surface was internalized within 10 minutes regardless of the presence of apoA-I. ABCA1 was intracellularly degraded and was protected against this only when exposed to extracellular apoA-I before its endocytosis. Consequently, recycle of ABCA1 to the surface was enhanced, and surface ABCA1 was increased by apoA-I. Direct inhibition of ABCA1 endocytosis led to decrease of its degradation and increase of surface ABCA1. Generation of HDL increased in parallel with surface ABCA1. CONCLUSIONS Surface ABCA1 is internalized and degraded, and apoA-I interferes with only the latter step to recycle ABCA1 to the surface. Increase of surface ABCA1 results in the increase of generation of HDL.
Collapse
Affiliation(s)
- Rui Lu
- Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | | | | | | | | |
Collapse
|
45
|
Subbaiah PV, Sowa JM, Singh DK. Sphingolipids and cellular cholesterol homeostasis. Effect of ceramide on cholesterol trafficking and HMG CoA reductase activity. Arch Biochem Biophys 2008; 474:32-8. [PMID: 18395507 PMCID: PMC2464457 DOI: 10.1016/j.abb.2008.03.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 03/18/2008] [Accepted: 03/20/2008] [Indexed: 01/19/2023]
Abstract
We previously showed that degradation of cellular sphingomyelin (SM) by SMase C results in a greater stimulation of cholesterol translocation to endoplasmic reticulum, compared to its degradation by SMase D. Here we investigated the hypothesis that the effect of SMase C is partly due to the generation of ceramide, rather than due to depletion of SM alone. Inhibition of hydroxymethylglutaryl CoA reductase (HMGCR) activity was used as a measure of cholesterol translocation. Treatment of fibroblasts with SMase C resulted in a 90% inhibition of HMGCR, whereas SMase D treatment inhibited it by 29%. Treatment with exogenous ceramides, or increasing the endogenous ceramide levels also inhibited HMGCR by 60-80%. Phosphorylation of HMGCR was stimulated by SMase C or exogenous ceramide. The effects of ceramide and SMase D were additive, indicating the independent effects of SM depletion and ceramide generation. These results show that ceramide regulates sterol trafficking independent of cellular SM levels.
Collapse
Affiliation(s)
- Papasani V Subbaiah
- Departments of Medicine and Biochemistry & Molecular Genetics, University of Illinois at Chicago, 1819 West Polk Street, M/C 797, Chicago, IL 60612, USA.
| | | | | |
Collapse
|
46
|
Abstract
We review evidence that sterols can form stoichiometric complexes with certain bilayer phospholipids, and sphingomyelin in particular. These complexes appear to be the basis for the formation of condensed and ordered liquid phases, (micro)domains and/or rafts in both artificial and biological membranes. The sterol content of a membrane can exceed the complexing capacity of its phospholipids. The excess, uncomplexed membrane sterol molecules have a relatively high escape tendency, also referred to as fugacity or chemical activity (and, here, simply activity). Cholesterol is also activated when certain membrane intercalating amphipaths displace it from the phospholipid complexes. Active cholesterol projects from the bilayer and is therefore highly susceptible to attack by cholesterol oxidase. Similarly, active cholesterol rapidly exits the plasma membrane to extracellular acceptors such as cyclodextrin and high-density lipoproteins. For the same reason, the pool of cholesterol in the ER (endoplasmic reticulum) increases sharply when cell surface cholesterol is incremented above the physiological set-point; i.e., equivalence with the complexing phospholipids. As a result, the escape tendency of the excess cholesterol not only returns the plasma membrane bilayer to its set-point but also serves as a feedback signal to intracellular homeostatic elements to down-regulate cholesterol accretion.
Collapse
|
47
|
Affiliation(s)
- John F Oram
- Department of Medicine, University of Washington, Seattle, WA, USA.
| |
Collapse
|
48
|
Faulkner LE, Panagotopulos SE, Johnson JD, Woollett LA, Hui DY, Witting SR, Maiorano JN, Davidson WS. An analysis of the role of a retroendocytosis pathway in ABCA1-mediated cholesterol efflux from macrophages. J Lipid Res 2008; 49:1322-32. [PMID: 18359958 DOI: 10.1194/jlr.m800048-jlr200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ATP binding cassette transporter A-1 (ABCA1) is critical for apolipoprotein-mediated cholesterol efflux, an important mechanism employed by macrophages to avoid becoming lipid-laden foam cells, the hallmark of early atherosclerotic lesions. It has been proposed that lipid-free apolipoprotein A-I (apoA-I) enters the cell and is resecreted as a lipidated particle via a retroendocytosis pathway during ABCA1-mediated cholesterol efflux from macrophages. To determine the functional importance of such a pathway, confocal microscopy was used to characterize the internalization of a fully functional apoA-I cysteine mutant containing a thiol-reactive fluorescent probe in cultured macrophages. ApoA-I was also endogenously labeled with (35)S-methionine to quantify cellular uptake and to determine the metabolic fate of the internalized protein. It was found that apoA-I was specifically taken inside macrophages and that a small amount of intact apoA-I was resecreted from the cells. However, a majority of the label that reappeared in the media was degraded. We estimate that the mass of apoA-I retroendocytosed is not sufficient to account for the HDL produced by the cholesterol efflux reaction. Furthermore, we have demonstrated that lipid-free apoA-I-mediated cholesterol efflux from macrophages can be pharmacologically uncoupled from apoA-I internalization into cells. On the basis these findings, we present a model in which the ABCA1-mediated lipid transfer process occurs primarily at the membrane surface in macrophages, but still accounts for the observed specific internalization of apoA-I.
Collapse
Affiliation(s)
- Loren E Faulkner
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati OH, 45237, USA
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Analysis of apolipoprotein E nuclear localization using green fluorescent protein and biotinylation approaches. Biochem J 2008; 409:701-9. [DOI: 10.1042/bj20071261] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Previous results indicate that apoE (apolipoprotein E) may be associated with the nucleus in specific cell types, particularly under stress conditions such as serum starvation. In addition, nuclear apoE localization in ovarian cancer was recently shown to be correlated with patient survival. In order to better understand the factors associated with apoE nuclear localization, we examined intracellular apoE trafficking using live-cell imaging of CHO (Chinese-hamster ovary) cells that constitutively expressed apoE–GFP (green fluorescent protein). In addition, we used biotinylated apoE (in a lipid-free state and as a lipidated discoidal complex) to track the uptake and potential nuclear targeting of exogenous apoE. Our results indicate that a small proportion of apoE–GFP is detected in the nucleus of living apoE–GFP-expressing CHO cells and that the level of apoE–GFP in the nucleus is increased with serum starvation. Exposure of control CHO cells to exogenous apoE–GFP did not result in nuclear apoE–GFP localization in the recipient cells. Similarly, biotinylated apoE did not reach the nucleus of control CHO cells or SK-N-SH neurons. In contrast, when biotinylated apoE was delivered to recipient cells as a lipidated apoE disc, apoE was detected in the nucleus, suggesting that the lipoprotein complex alters the intracellular degradation or trafficking of apoE. Biotinylated apoE discs containing each of the three common human apoE isoforms (E2, E3 and E4) were also tested for nuclear trafficking. All three apoE isoforms were equally detected in the nucleus. These studies provide new evidence that apoE may be targeted to the nucleus and shed light on factors that regulate this process.
Collapse
|
50
|
Puca AA, Chatgilialoglu C, Ferreri C. Lipid metabolism and diet: Possible mechanisms of slow aging. Int J Biochem Cell Biol 2008; 40:324-33. [PMID: 17509925 DOI: 10.1016/j.biocel.2007.04.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 04/02/2007] [Accepted: 04/03/2007] [Indexed: 11/22/2022]
Abstract
The ability to survive to an extremely old age is a consequence of complex interactions among genes, environment, lifestyle and luck. In the last two centuries, life expectancy in western countries has doubled, increasing from 40 to 81 years (79 for males and 82 for females). The candidate factors to determine such mortality reduction are reduced exposure to infections and the subsequent reduction in inflammatory responses, and to some extent, improvement in diet and nutrition. Among the people born at the beginning of the previous century, a small portion of individuals (1 in 10,000 born) have reached 100 years, surviving approximately 20 years more than the general population. The successful longevity of these individuals shows a familial component, possibly genetic, as underlined by the centenarian sibling's increased chance of reaching 100 years of age compared to the general population. Genetic studies on long living individuals have led to the discovery of potential genetic causes of extreme longevity. These discoveries have highlighted the role of lipid metabolism as a potential key player in the ability to survive to extreme old age. Additional studies on the longevity phenotype have confirmed the role of lipids and lipid-associated cell activities in the predisposition to longevity, from lower eukaryotes to humans. The main focus of this review is the appreciation of demographic survival data and changes in recent diet with the above mentioned genetic and phenotypic biomarkers of longevity, in order to elucidate hypotheses on mechanisms of slow aging and disease resistance.
Collapse
|