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Liu JJ, Green P, John Mann J, Rapoport SI, Sublette ME. Pathways of polyunsaturated fatty acid utilization: implications for brain function in neuropsychiatric health and disease. Brain Res 2015; 1597:220-46. [PMID: 25498862 PMCID: PMC4339314 DOI: 10.1016/j.brainres.2014.11.059] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/11/2014] [Accepted: 11/27/2014] [Indexed: 12/28/2022]
Abstract
Essential polyunsaturated fatty acids (PUFAs) have profound effects on brain development and function. Abnormalities of PUFA status have been implicated in neuropsychiatric diseases such as major depression, bipolar disorder, schizophrenia, Alzheimer's disease, and attention deficit hyperactivity disorder. Pathophysiologic mechanisms could involve not only suboptimal PUFA intake, but also metabolic and genetic abnormalities, defective hepatic metabolism, and problems with diffusion and transport. This article provides an overview of physiologic factors regulating PUFA utilization, highlighting their relevance to neuropsychiatric disease.
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Affiliation(s)
- Joanne J Liu
- Department of Molecular Imaging & Neuropathology, New York State Psychiatric Institute, New York, NY, USA; New York Medical College, Valhalla, NY, USA
| | - Pnina Green
- Laboratory of Metabolic Research, Felsenstein Medical Research Center, Tel Aviv University, Petach Tikva, Israel
| | - J John Mann
- Department of Molecular Imaging & Neuropathology, New York State Psychiatric Institute, New York, NY, USA; Department of Psychiatry, Columbia University, New York, NY, USA; Department of Radiology, Columbia University, New York, NY, USA
| | - Stanley I Rapoport
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - M Elizabeth Sublette
- Department of Molecular Imaging & Neuropathology, New York State Psychiatric Institute, New York, NY, USA; Department of Psychiatry, Columbia University, New York, NY, USA.
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Liu J, Ma DWL. The role of n-3 polyunsaturated fatty acids in the prevention and treatment of breast cancer. Nutrients 2014; 6:5184-223. [PMID: 25412153 PMCID: PMC4245586 DOI: 10.3390/nu6115184] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/28/2014] [Accepted: 11/04/2014] [Indexed: 02/07/2023] Open
Abstract
Breast cancer (BC) is the most common cancer among women worldwide. Dietary fatty acids, especially n-3 polyunsaturated fatty acids (PUFA), are believed to play a role in reducing BC risk. Evidence has shown that fish consumption or intake of long-chain n-3 PUFA, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are beneficial for inhibiting mammary carcinogenesis. The evidence regarding α-linolenic acid (ALA), however, remains equivocal. It is essential to clarify the relation between ALA and cancer since ALA is the principal source of n-3 PUFA in the Western diet and the conversion of ALA to EPA and DHA is not efficient in humans. In addition, the specific anticancer roles of individual n-3 PUFA, alone, have not yet been identified. Therefore, the present review evaluates ALA, EPA and DHA consumed individually as well as in n-3 PUFA mixtures. Also, their role in the prevention of BC and potential anticancer mechanisms of action are examined. Overall, this review suggests that each n-3 PUFA has promising anticancer effects and warrants further research.
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Affiliation(s)
- Jiajie Liu
- Department of Human Health & Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada.
| | - David W L Ma
- Department of Human Health & Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Guéguinou M, Gambade A, Félix R, Chantôme A, Fourbon Y, Bougnoux P, Weber G, Potier-Cartereau M, Vandier C. Lipid rafts, KCa/ClCa/Ca2+ channel complexes and EGFR signaling: Novel targets to reduce tumor development by lipids? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:2603-20. [PMID: 25450343 DOI: 10.1016/j.bbamem.2014.10.036] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/15/2014] [Accepted: 10/22/2014] [Indexed: 12/29/2022]
Abstract
Membrane lipid rafts are distinct plasma membrane nanodomains that are enriched with cholesterol, sphingolipids and gangliosides, with occasional presence of saturated fatty acids and phospholipids containing saturated acyl chains. It is well known that they organize receptors (such as Epithelial Growth Factor Receptor), ion channels and their downstream acting molecules to regulate intracellular signaling pathways. Among them are Ca2+ signaling pathways, which are modified in tumor cells and inhibited upon membrane raft disruption. In addition to protein components, lipids from rafts also contribute to the organization and function of Ca2+ signaling microdomains. This article aims to focus on the lipid raft KCa/ClCa/Ca2+ channel complexes that regulate Ca2+ and EGFR signaling in cancer cells, and discusses the potential modification of these complexes by lipids as a novel therapeutic approach in tumor development. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Maxime Guéguinou
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Audrey Gambade
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Romain Félix
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Aurélie Chantôme
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Yann Fourbon
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Philippe Bougnoux
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France; Centre HS Kaplan, CHRU Tours, Tours F-37032, France
| | - Günther Weber
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Marie Potier-Cartereau
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France
| | - Christophe Vandier
- Inserm, UMR1069, Nutrition, Croissance et Cancer, Tours F-37032, France; Université François Rabelais, Tours F-37032, France.
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D'Antona G, Nabavi SM, Micheletti P, Di Lorenzo A, Aquilani R, Nisoli E, Rondanelli M, Daglia M. Creatine, L-carnitine, and ω3 polyunsaturated fatty acid supplementation from healthy to diseased skeletal muscle. BIOMED RESEARCH INTERNATIONAL 2014; 2014:613890. [PMID: 25243159 PMCID: PMC4163371 DOI: 10.1155/2014/613890] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/19/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022]
Abstract
Myopathies are chronic degenerative pathologies that induce the deterioration of the structure and function of skeletal muscle. So far a definitive therapy has not yet been developed and the main aim of myopathy treatment is to slow the progression of the disease. Current nonpharmacological therapies include rehabilitation, ventilator assistance, and nutritional supplements, all of which aim to delay the onset of the disease and relieve its symptoms. Besides an adequate diet, nutritional supplements could play an important role in the treatment of myopathic patients. Here we review the most recent in vitro and in vivo studies investigating the role supplementation with creatine, L-carnitine, and ω3 PUFAs plays in myopathy treatment. Our results suggest that these dietary supplements could have beneficial effects; nevertheless continued studies are required before they could be recommended as a routine treatment in muscle diseases.
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Affiliation(s)
- Giuseppe D'Antona
- Department of Molecular Medicine and Laboratory for Motor Activities in Rare Diseases (LUSAMMR), University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
| | - Seyed Mohammad Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, P.O. Box 19395-5487, Tehran, Iran
| | - Piero Micheletti
- Department of Experimental and Forensic Medicine, University of Pavia, Via Forlanini 2, 27100 Pavia, Italy
| | - Arianna Di Lorenzo
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Roberto Aquilani
- Maugeri Foundation IRCCS, Montescano Scientific Institute, Via Per Montescano 31, 27040 Montescano, Italy
| | - Enzo Nisoli
- Center for Study and Research on Obesity, Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Vanvitelli 32, 20129 Milan, Italy
| | - Mariangela Rondanelli
- Human Nutrition Section, Health Sciences Department, University of Pavia, Azienda di Servizi alla Persona, Via Emilia 12, 27100 Pavia, Italy
| | - Maria Daglia
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy
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Chapkin RS, DeClercq V, Kim E, Fuentes NR, Fan YY. Mechanisms by Which Pleiotropic Amphiphilic n-3 PUFA Reduce Colon Cancer Risk. CURRENT COLORECTAL CANCER REPORTS 2014; 10:442-452. [PMID: 25400530 DOI: 10.1007/s11888-014-0241-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. Genetic susceptibility and diet are primary determinants of cancer risk and tumor behavior. Experimental, epidemiological, and clinical data substantiate the beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing chronic inflammation and colon cancer. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely alters membrane structure/ cytoskeletal function, impacting membrane receptor function and downstream signaling cascades, including gene expression profiles and cell phenotype. In addition, n-3 PUFA can synergize with other potential anti-tumor agents, such as fermentable fiber and curcumin. With the rising prevalence of diet-induced obesity, there is also an urgent need to elucidate the link between chronic inflammation in adipose tissue and colon cancer risk in obesity. In this review, we will summarize recent developments linking n-3 PUFA intake, membrane alterations, epigenetic modulation, and effects on obesity-associated colon cancer risk.
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Affiliation(s)
- Robert S Chapkin
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX 77843, USA. Center for Translational Environmental Health Research, Texas A&M University, College Station, TX 77843, USA. Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA. Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843, USA. Faculty of Toxicity, Texas A&M University, College Station, TX 77843, USA
| | - Vanessa DeClercq
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX 77843, USA. Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA
| | - Eunjoo Kim
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX 77843, USA. Molecular & Cellular Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Natividad Roberto Fuentes
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX 77843, USA. Faculty of Toxicity, Texas A&M University, College Station, TX 77843, USA
| | - Yang-Yi Fan
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX 77843, USA. Department of Nutrition and Food Science, Texas A&M University, College Station, TX 77843, USA
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Yang G, Xu H, Li Z, Li F. Interactions of caveolin-1 scaffolding and intramembrane regions containing a CRAC motif with cholesterol in lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2588-99. [PMID: 24998359 DOI: 10.1016/j.bbamem.2014.06.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/13/2014] [Accepted: 06/22/2014] [Indexed: 11/27/2022]
Abstract
Caveolin-1 is a major structural protein of caveolae and specifically binds cholesterol (Chol). The caveolin scaffolding domain is thought to be involved in caveolin-Chol interaction through the sequence V94-T-K-Y-W-F-Y-R101, a motif that matches a cholesterol recognition amino-acid consensus (CRAC). In the present work, three CRAC-containing peptides, corresponding to caveolin-1 94-101, 82-101 and 93-126, were tested to study the role of the CRAC motif in the caveolin-Chol interaction in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers using differential scanning calorimetry (DSC), fluorescence and circular dichroism (CD). The Y97I substituents of the three peptides and one peptide segment corresponding to caveolin-1 101-126 that excludes the CRAC motif were also tested for comparison. Our results showed the potency of these CRAC-containing peptides in sequestering Chol into domains and the enhanced role of the intramembrane domain and scaffolding domain for the potency. Of the three CRAC-containing peptides, the peptide 93-126 was particularly effective in promoting Chol segregation, while the peptide 82-101 was less potent in promoting the formation of domains than the peptide 93-126, but was more potent than the peptide 94-101. The domain partition of DPPC/Chol bilayers was not observed in the presence of the peptide 101-126, in contrast to the case in the presence of the peptide 93-126 at the same concentrations of peptide and Chol. The potency of the CRAC motif in Chol segregation was lowered by the Y97I mutation. The difference in structure may be a factor that contributes to different effects of these peptides on the distribution of Chol in the lipid membrane.
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Affiliation(s)
- Guanhua Yang
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, PR China
| | - Haoran Xu
- Key Laboratory for Molecular Enzymology & Engineering, The Ministry of Education, Jilin University, Changchun 130012, PR China
| | - Zhengqiang Li
- Key Laboratory for Molecular Enzymology & Engineering, The Ministry of Education, Jilin University, Changchun 130012, PR China
| | - Fei Li
- State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, PR China.
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Hofmanová J, Straková N, Vaculová AH, Tylichová Z, Šafaříková B, Skender B, Kozubík A. Interaction of dietary fatty acids with tumour necrosis factor family cytokines during colon inflammation and cancer. Mediators Inflamm 2014; 2014:848632. [PMID: 24876678 PMCID: PMC4021685 DOI: 10.1155/2014/848632] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/29/2014] [Indexed: 12/14/2022] Open
Abstract
Intestinal homeostasis is precisely regulated by a number of endogenous regulatory molecules but significantly influenced by dietary compounds. Malfunction of this system may result in chronic inflammation and cancer. Dietary essential n-3 polyunsaturated fatty acids (PUFAs) and short-chain fatty acid butyrate produced from fibre display anti-inflammatory and anticancer activities. Both compounds were shown to modulate the production and activities of TNF family cytokines. Cytokines from the TNF family (TNF- α, TRAIL, and FasL) have potent inflammatory activities and can also regulate apoptosis, which plays an important role in cancer development. The results of our own research showed enhancement of apoptosis in colon cancer cells by a combination of either docosahexaenoic acid (DHA) or butyrate with TNF family cytokines, especially by promotion of the mitochondrial apoptotic pathway and modulation of NF κ B activity. This review is focused mainly on the interaction of dietary PUFAs and butyrate with these cytokines during colon inflammation and cancer development. We summarised recent knowledge about the cellular and molecular mechanisms involved in such effects and outcomes for intestinal cell behaviour and pathologies. Finally, the possible application for the prevention and therapy of colon inflammation and cancer is also outlined.
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Affiliation(s)
- Jiřina Hofmanová
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Nicol Straková
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Alena Hyršlová Vaculová
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Zuzana Tylichová
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Barbora Šafaříková
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Belma Skender
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Alois Kozubík
- Department of Cytokinetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
- Institute of Experimental Biology, Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
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Yamanushi TT, Kabuto H, Hirakawa E, Janjua N, Takayama F, Mankura M. Oral administration of eicosapentaenoic acid or docosahexaenoic acid modifies cardiac function and ameliorates congestive heart failure in male rats. J Nutr 2014; 144:467-74. [PMID: 24523492 DOI: 10.3945/jn.113.175125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
This study assessed the effects of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) on normal cardiac function (part 1) and congestive heart failure (CHF) (part 2) through electrocardiogram analysis and determination of EPA, DHA, and arachidonic acid (AA) concentrations in rat hearts. In part 2, pathologic assessments were also performed. For part 1 of this study, 4-wk-old male rats were divided into a control group and 2 experimental groups. The rats daily were orally administered (1 g/kg body weight) saline, EPA-ethyl ester (EPA-Et; E group), or DHA-ethyl ester (DHA-Et; D group), respectively, for 28 d. ECGs revealed that QT intervals were significantly shorter for groups E and D compared with the control group (P ≤ 0.05). Relative to the control group, the concentration of EPA was higher in the E group and concentrations of EPA and DHA were higher in the D group, although AA concentrations were lower (P ≤ 0.05). In part 2, CHF was produced by subcutaneous injection of monocrotaline into 5-wk-old rats. At 3 d before monocrotaline injection, rats were administered either saline, EPA-Et, or DHA-Et as mentioned above and then killed at 21 d. The study groups were as follows: normal + saline (control), CHF + saline (H group), CHF + EPA-Et (HE group), and CHF + DHA-Et (HD group). QT intervals were significantly shorter (P ≤ 0.05) in the control and HD groups compared with the H and HE groups. Relative to the H group, concentrations of EPA were higher in the HE group and those of DHA were higher in the control and HD groups (P ≤ 0.05). There was less mononuclear cell infiltration in the myocytes of the HD group than in the H group (P = 0.06). The right ventricles in the H, HE, and HD groups showed significantly increased weights (P ≤ 0.05) compared with controls. The administration of EPA-Et or DHA-Et may affect cardiac function by modification of heart fatty acid composition, and the administration of DHA-Et may ameliorate CHF.
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Affiliation(s)
- Tomoko T Yamanushi
- Kagawa Prefectural University of Health Sciences, Takamatsu City, Kagawa, Japan
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Bürgin-Maunder CS, Brooks PR, Russell FD. Omega-3 fatty acids modulate Weibel-Palade body degranulation and actin cytoskeleton rearrangement in PMA-stimulated human umbilical vein endothelial cells. Mar Drugs 2013; 11:4435-50. [PMID: 24217286 PMCID: PMC3853737 DOI: 10.3390/md11114435] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/15/2013] [Accepted: 10/22/2013] [Indexed: 01/03/2023] Open
Abstract
Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) produce cardiovascular benefits by improving endothelial function. Endothelial cells store von Willebrand factor (vWF) in cytoplasmic Weibel-Palade bodies (WPBs). We examined whether LC n-3 PUFAs regulate WPB degranulation using cultured human umbilical vein endothelial cells (HUVECs). HUVECs were incubated with or without 75 or 120 µM docosahexaenoic acid or eicosapentaenoic acid for 5 days at 37 °C. WPB degranulation was stimulated using phorbol 12-myristate 13-acetate (PMA), and this was assessed by immunocytochemical staining for vWF. Actin reorganization was determined using phalloidin-TRITC staining. We found that PMA stimulated WPB degranulation, and that this was significantly reduced by prior incubation of cells with LC n-3 PUFAs. In these cells, WPBs had rounded rather than rod-shaped morphology and localized to the perinuclear region, suggesting interference with cytoskeletal remodeling that is necessary for complete WPB degranulation. In line with this, actin rearrangement was altered in cells containing perinuclear WPBs, where cells exhibited a thickened actin rim in the absence of prominent cytoplasmic stress fibers. These findings indicate that LC n-3 PUFAs provide some protection against WBP degranulation, and may contribute to an improved understanding of the anti-thrombotic effects previously attributed to LC n-3 PUFAs.
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Affiliation(s)
- Corinna S Bürgin-Maunder
- Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Queensland 4556, Australia.
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Cho Y, Turner ND, Davidson LA, Chapkin RS, Carroll RJ, Lupton JR. A chemoprotective fish oil/pectin diet enhances apoptosis via Bcl-2 promoter methylation in rat azoxymethane-induced carcinomas. Exp Biol Med (Maywood) 2013; 237:1387-93. [PMID: 23354397 DOI: 10.1258/ebm.2012.012244] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We have demonstrated that diets containing fish oil and pectin (FO/P) reduce colon tumor incidence relative to control (corn oil and cellulose [CO/C]) in part by inducing apoptosis of DNA-damaged colon cells. Relative to FO/P, CO/C promotes colonocyte expression of the antiapoptotic modulator, Bcl-2, and Bcl-2 promoter methylation is altered in colon cancer. To determine if FO/P, compared with CO/C, limits Bcl-2 expression by enhancing promoter methylation in colon tumors, we examined Bcl-2 promoter methylation, mRNA levels, colonocyte apoptosis and colon tumor incidence in azoxymethane (AOM)-injected rats. Rats were provided diets containing FO/P or CO/C, and were terminated 16 and 34 weeks after AOM injection. DNA isolated from paraformaldehyde-fixed colon tumors and uninvolved tissue was bisulfite modified and amplified by quantitative reverese transcriptase-polymerase chain reaction to assess DNA methylation in Bcl-2 cytosine-guanosine islands. FO/P increased Bcl-2 promoter methylation (P = 0.009) in tumor tissues and colonocyte apoptosis (P = 0.020) relative to CO/C. An inverse correlation between Bcl-2 DNA methylation and Bcl-2 mRNA levels was observed in the tumors. We conclude that dietary FO/P promotes apoptosis in part by enhancing Bcl-2 promoter methylation. These Bcl-2 promoter methylation responses, measured in vivo, contribute to our understanding of the mechanisms involved in chemoprevention of colon cancer by diets containing FO/P.
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Affiliation(s)
- Youngmi Cho
- Faculty of Nutrition, Texas A&M University, College Station, TX 77843, USA
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Petrescu AD, Huang H, Martin GG, McIntosh AL, Storey SM, Landrock D, Kier AB, Schroeder F. Impact of L-FABP and glucose on polyunsaturated fatty acid induction of PPARα-regulated β-oxidative enzymes. Am J Physiol Gastrointest Liver Physiol 2013; 304:G241-56. [PMID: 23238934 PMCID: PMC3566512 DOI: 10.1152/ajpgi.00334.2012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Liver fatty acid binding protein (L-FABP) is the major soluble protein that binds very-long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs) in hepatocytes. However, nothing is known about L-FABP's role in n-3 PUFA-mediated peroxisome proliferator activated receptor-α (PPARα) transcription of proteins involved in long-chain fatty acid (LCFA) β-oxidation. This issue was addressed in cultured primary hepatocytes from wild-type, L-FABP-null, and PPARα-null mice with these major findings: 1) PUFA-mediated increase in the expression of PPARα-regulated LCFA β-oxidative enzymes, LCFA/LCFA-CoA binding proteins (L-FABP, ACBP), and PPARα itself was L-FABP dependent; 2) PPARα transcription, robustly potentiated by high glucose but not maltose, a sugar not taken up, correlated with higher protein levels of these LCFA β-oxidative enzymes and with increased LCFA β-oxidation; and 3) high glucose altered the potency of n-3 relative to n-6 PUFA. This was not due to a direct effect of glucose on PPARα transcriptional activity nor indirectly through de novo fatty acid synthesis from glucose. Synergism was also not due to glucose impacting other signaling pathways, since it was observed only in hepatocytes expressing both L-FABP and PPARα. Ablation of L-FABP or PPARα as well as treatment with MK886 (PPARα inhibitor) abolished/reduced PUFA-mediated PPARα transcription of these genes, especially at high glucose. Finally, the PUFA-enhanced L-FABP distribution into nuclei with high glucose augmentation of the L-FABP/PPARα interaction reveals not only the importance of L-FABP for PUFA induction of PPARα target genes in fatty acid β-oxidation but also the significance of a high glucose enhancement effect in diabetes.
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Affiliation(s)
- Anca D. Petrescu
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
| | - Huan Huang
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
| | - Gregory G. Martin
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
| | - Avery L. McIntosh
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
| | - Stephen M. Storey
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
| | - Danilo Landrock
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
| | - Ann B. Kier
- 2Department of Pathobiology, Texas A&M University, TVMC, College Station, Texas
| | - Friedhelm Schroeder
- 1Department of Physiology and Pharmacology, Texas A&M University, TVMC, College Station, Texas; and
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Myogenic differentiation and lipid-raft composition of L6 skeletal muscle cells are modulated by PUFAs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:602-13. [DOI: 10.1016/j.bbamem.2012.10.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 10/08/2012] [Accepted: 10/10/2012] [Indexed: 11/20/2022]
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63
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Gortan Cappellari G, Losurdo P, Mazzucco S, Panizon E, Jevnicar M, Macaluso L, Fabris B, Barazzoni R, Biolo G, Carretta R, Zanetti M. Treatment with n-3 polyunsaturated fatty acids reverses endothelial dysfunction and oxidative stress in experimental menopause. J Nutr Biochem 2013; 24:371-9. [DOI: 10.1016/j.jnutbio.2012.07.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/12/2012] [Accepted: 07/20/2012] [Indexed: 10/27/2022]
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64
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Turk HF, Chapkin RS. Membrane lipid raft organization is uniquely modified by n-3 polyunsaturated fatty acids. Prostaglandins Leukot Essent Fatty Acids 2013; 88:43-7. [PMID: 22515942 PMCID: PMC3404206 DOI: 10.1016/j.plefa.2012.03.008] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 03/27/2012] [Accepted: 03/28/2012] [Indexed: 01/20/2023]
Abstract
Fish oil, enriched in bioactive n-3 polyunsaturated fatty acids (PUFA), has been shown to play a role in prevention of colon cancer. The effects of n-3 PUFA are pleiotropic and multifaceted, resulting in an incomplete understanding of their molecular mechanisms of action. Here, we focus on a highly conserved mechanism of n-3 PUFA, which is the alteration of the organization of the plasma membrane. We highlight recent work demonstrating that enrichment of n-3 PUFA in the plasma membrane alters the lateral organization of membrane signaling assemblies (i.e. lipid rafts). This mechanism is central for n-3 PUFA regulation of downstream signaling, T-cell activation, transcriptional activation, and cytokine secretion. We conclude that these studies provide strong evidence for a predominant mechanism by which n-3 PUFA function in colon cancer prevention.
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Affiliation(s)
- Harmony F Turk
- Program in Integrative Nutrition and Complex Diseases and the Center for Environmental and Rural Health, Texas A&M University, College Station, TX 77843, USA
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KrawczyńSka A, Olczak E, Rembiszewska A, Gromadzka-Ostrowska J. High-fat, cholesterol-rich diet affects leptin expression in the aortic layers. Exp Biol Med (Maywood) 2013; 238:47-56. [DOI: 10.1258/ebm.2012.012228] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Leptin is stated to be an important mediator between obesity and cardiovascular disease. However, whether leptin location in the aorta is dependent on diet and its atherogenic character is still unknown. This study examined the relationship between a high-fat diet with or without cholesterol and the expression of leptin in aortic layers. Forty male rats were fed a high-fat diet with fish or grape seed oil as a dietary fat source, with or without cholesterol, to enhance the atherogenic character of their diet. The experiments lasted for three and six weeks, respectively. Plasma lipid profile, plasma leptin concentration and leptin expression in the endothelium (E), myometrium (M) and adventitia (A) were examined. The length of feeding was a key factor which influenced both the lipid profile and leptin expression in the aorta. Leptin concentration positively correlated with body weight and plasma triglycerides only in the three-week experiment, which suggests that the physiological actions of leptin can be disturbed by prolonged consumption of a high-fat diet. Short-term intake of a high-fat diet with fish oil, increasing high density lipoprotein cholesterol (HDL) level and decreasing total cholesterol (TC)/HDL ratio, enhanced leptin expression in E in comparison to the group fed grape seed oil. However, in the group with the highest diet intake, leptin expression in each layer was lowest. Generally, leptin expression was most common in E; however, an extension of the period of feeding in groups fed a diet with grape seed oil with or without additional cholesterol increased leptin presence in M and A in comparison to the group fed fish oil. Significantly higher values of TC and HDL in the same groups may suggest that leptin changes in the aorta and the atherogenic impact of grape seed oil can be connected when the consumption of a high-fat diet is excessive.
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Affiliation(s)
- Agata KrawczyńSka
- The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Laboratory of Molecular Biology, ul. Instytucka 3, 05-110 Jablonna
| | - Elzbieta Olczak
- Division of Nutrition Physiology, Department of Dietetics, Faculty of Human Nutrition and Consumer Science, Warsaw University of Life Sciences - SGGW, 02-776 Warsaw
| | - Alina Rembiszewska
- Department of Molecular Pathology, The Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, 02-776 Warsaw, Poland
| | - Joanna Gromadzka-Ostrowska
- Division of Nutrition Physiology, Department of Dietetics, Faculty of Human Nutrition and Consumer Science, Warsaw University of Life Sciences - SGGW, 02-776 Warsaw
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66
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Terashima M, Aoyama-Ishikawa M, Ueda T, Hagi A, Usami M, Nakao A, Kotani J. The effects of n-3 polyunsaturated fatty acid-rich total parenteral nutrition on neutrophil apoptosis in a rat endotoxemia. J Clin Biochem Nutr 2012; 52:154-9. [PMID: 23524349 PMCID: PMC3593133 DOI: 10.3164/jcbn.12-86] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 08/19/2012] [Indexed: 01/12/2023] Open
Abstract
Although recruited neutrophils function as first-line defense to remove bacteria, delayed apoptosis is implicated in persistent inflammation leading to organ injury. Leukotrien B4, n-6 polyunsaturated fatty acids (PUFAs) product, is one of the mediators that delay neutrophil apoptosis. The mechanism of the beneficial effects of supplementation of fish oil-based long-chain n-3 PUFAs in parenteral nutrition for critically ill patients has not been fully understood. One possible mechanism is the less inflammatory n-3 PUFAs products can compete with proinflammatory n-6 PUFAs products for access to the enzymes. The aim of this study was to determine whether n-3 PUFA rich parenteral nutrition may alter the composition of fatty acids in the neutrophil membrane and restore delay of neutrophil apoptosis during endotoxin-induced systemic inflammation in rats. The animals in group 1 were treated with 20% Hicaliq NC-N in Neoparen-2 for three days. The animals in group 2 (referred to as n-6 PUFA-rich parenteral nutrition) were given parenteral nutrition solutions containing 20% soybean oil in Neoparen-2 (n-6/n-3 = 10). The animals in group 3 (referred to as n-3 PUFA-rich parenteral nutrition) were administered parenteral nutrition consisting of 10% soybean oil and 10% fish oil emulsion (n-6/n-3 = 1.3). The n-3/n-6 ratio of the neutrophil membrane was significantly increased in group 3 and was associated with restored lipopolysaccharide-delayed-apoptosis of neutrophils in bone marrow cells and increased production of leukotriene B5 from peritoneal neutrophils stimulated by lipopolysaccharide. Our preliminary results showed that n-3 PUFA-rich parenteral nutrition regulated neutrophil apoptosis and prevented synthesis of pro-inflammatory eicosanoids, explaining the protective effects seen in the clinical setting.
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Affiliation(s)
- Mariko Terashima
- Department of Emergency and Critical Care Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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Antifibrotic effects of ω-3 fatty acids in the heart: one possible treatment for diastolic heart failure. Trends Cardiovasc Med 2012; 21:90-5. [PMID: 22626248 DOI: 10.1016/j.tcm.2012.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Half of heart failure patients have diastolic heart failure, which has no effective treatments. Several studies indicate a role for ω-3 polyunsaturated fatty acids (PUFAs) in heart failure. Recent studies suggest that ω-3 PUFAs inhibit cardiac fibrosis and attenuate diastolic dysfunction. This opens up possible new avenues for treatment of diastolic heart failure. In this review, we focus on the antifibrotic effects of ω-3 PUFAs in heart and the underlying cellular and molecular mechanisms.
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68
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Agbor LN, Walsh MT, Boberg JR, Walker MK. Elevated blood pressure in cytochrome P4501A1 knockout mice is associated with reduced vasodilation to omega-3 polyunsaturated fatty acids. Toxicol Appl Pharmacol 2012; 264:351-60. [PMID: 22995157 DOI: 10.1016/j.taap.2012.09.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/04/2012] [Accepted: 09/09/2012] [Indexed: 01/19/2023]
Abstract
In vitro cytochrome P4501A1 (CYP1A1) metabolizes omega-3 polyunsaturated fatty acids (n-3 PUFAs); eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), primarily to 17,18-epoxyeicosatetraenoic acid (17,18-EEQ) and 19,20-epoxydocosapentaenoic acid (19,20-EDP), respectively. These metabolites have been shown to mediate vasodilation via increases in nitric oxide (NO) and activation of potassium channels. We hypothesized that genetic deletion of CYP1A1 would reduce vasodilatory responses to n-3 PUFAs, but not the metabolites, and increase blood pressure (BP) due to decreases in NO. We assessed BP by radiotelemetry in CYP1A1 wildtype (WT) and knockout (KO) mice±NO synthase (NOS) inhibitor. We also assessed vasodilation to acetylcholine (ACh), EPA, DHA, 17,18-EEQ and 19,20-EDP in aorta and mesenteric arterioles. Further, we assessed vasodilation to an NO donor and to DHA±inhibitors of potassium channels. CYP1A1 KO mice were hypertensive, compared to WT, (mean BP in mmHg, WT 103±1, KO 116±1, n=5/genotype, p<0.05), and exhibited a reduced heart rate (beats per minute, WT 575±5; KO 530±7; p<0.05). However, BP responses to NOS inhibition and vasorelaxation responses to ACh and an NO donor were normal in CYP1A1 KO mice, suggesting that NO bioavailability was not reduced. In contrast, CYP1A1 KO mice exhibited significantly attenuated vasorelaxation responses to EPA and DHA in both the aorta and mesenteric arterioles, but normal vasorelaxation responses to the CYP1A1 metabolites, 17,18-EEQ and 19,20-EDP, and normal responses to potassium channel inhibition. Taken together these data suggest that CYP1A1 metabolizes n-3 PUFAs to vasodilators in vivo and the loss of these vasodilators may lead to increases in BP.
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Affiliation(s)
- Larry N Agbor
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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69
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Turk HF, Barhoumi R, Chapkin RS. Alteration of EGFR spatiotemporal dynamics suppresses signal transduction. PLoS One 2012; 7:e39682. [PMID: 22761867 PMCID: PMC3384615 DOI: 10.1371/journal.pone.0039682] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 05/29/2012] [Indexed: 01/18/2023] Open
Abstract
The epidermal growth factor receptor (EGFR), which regulates cell growth and survival, is integral to colon tumorigenesis. Lipid rafts play a role in regulating EGFR signaling, and docosahexaenoic acid (DHA) is known to perturb membrane domain organization through changes in lipid rafts. Therefore, we investigated the mechanistic link between EGFR function and DHA. Membrane incorporation of DHA into immortalized colonocytes altered the lateral organization of EGFR. DHA additionally increased EGFR phosphorylation but paradoxically suppressed downstream signaling. Assessment of the EGFR-Ras-ERK1/2 signaling cascade identified Ras GTP binding as the locus of the DHA-induced disruption of signal transduction. DHA also antagonized EGFR signaling capacity by increasing receptor internalization and degradation. DHA suppressed cell proliferation in an EGFR-dependent manner, but cell proliferation could be partially rescued by expression of constitutively active Ras. Feeding chronically-inflamed, carcinogen-injected C57BL/6 mice a fish oil containing diet enriched in DHA recapitulated the effects on the EGFR signaling axis observed in cell culture and additionally suppressed tumor formation. We conclude that DHA-induced alteration in both the lateral and subcellular localization of EGFR culminates in the suppression of EGFR downstream signal transduction, which has implications for the molecular basis of colon cancer prevention by DHA.
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Affiliation(s)
- Harmony F. Turk
- Program in Integrative Nutrition and Complex Diseases, Texas A & M University, College Station, Texas, United States of America
| | - Rola Barhoumi
- Image Analysis Laboratory, Texas A & M University, College Station, Texas, United States of America
| | - Robert S. Chapkin
- Program in Integrative Nutrition and Complex Diseases, Texas A & M University, College Station, Texas, United States of America
- Center for Environmental and Rural Health, Texas A & M University, College Station, Texas, United States of America
- * E-mail:
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70
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Omega-3 fatty acids and cardiovascular disease: effects on risk factors, molecular pathways, and clinical events. J Am Coll Cardiol 2011; 58:2047-67. [PMID: 22051327 DOI: 10.1016/j.jacc.2011.06.063] [Citation(s) in RCA: 1126] [Impact Index Per Article: 86.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 06/08/2011] [Accepted: 06/16/2011] [Indexed: 11/22/2022]
Abstract
We reviewed available evidence for cardiovascular effects of n-3 polyunsaturated fatty acid (PUFA) consumption, focusing on long chain (seafood) n-3 PUFA, including their principal dietary sources, effects on physiological risk factors, potential molecular pathways and bioactive metabolites, effects on specific clinical endpoints, and existing dietary guidelines. Major dietary sources include fatty fish and other seafood. n-3 PUFA consumption lowers plasma triglycerides, resting heart rate, and blood pressure and might also improve myocardial filling and efficiency, lower inflammation, and improve vascular function. Experimental studies demonstrate direct anti-arrhythmic effects, which have been challenging to document in humans. n-3 PUFA affect a myriad of molecular pathways, including alteration of physical and chemical properties of cellular membranes, direct interaction with and modulation of membrane channels and proteins, regulation of gene expression via nuclear receptors and transcription factors, changes in eicosanoid profiles, and conversion of n-3 PUFA to bioactive metabolites. In prospective observational studies and adequately powered randomized clinical trials, benefits of n-3 PUFA seem most consistent for coronary heart disease mortality and sudden cardiac death. Potential effects on other cardiovascular outcomes are less-well-established, including conflicting evidence from observational studies and/or randomized trials for effects on nonfatal myocardial infarction, ischemic stroke, atrial fibrillation, recurrent ventricular arrhythmias, and heart failure. Research gaps include the relative importance of different physiological and molecular mechanisms, precise dose-responses of physiological and clinical effects, whether fish oil provides all the benefits of fish consumption, and clinical effects of plant-derived n-3 PUFA. Overall, current data provide strong concordant evidence that n-3 PUFA are bioactive compounds that reduce risk of cardiac death. National and international guidelines have converged on consistent recommendations for the general population to consume at least 250 mg/day of long-chain n-3 PUFA or at least 2 servings/week of oily fish.
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71
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Aliche-Djoudi F, Podechard N, Chevanne M, Nourissat P, Catheline D, Legrand P, Dimanche-Boitrel MT, Lagadic-Gossmann D, Sergent O. Physical and chemical modulation of lipid rafts by a dietary n-3 polyunsaturated fatty acid increases ethanol-induced oxidative stress. Free Radic Biol Med 2011; 51:2018-30. [PMID: 21945097 DOI: 10.1016/j.freeradbiomed.2011.08.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 08/25/2011] [Accepted: 08/25/2011] [Indexed: 12/28/2022]
Abstract
Dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) have been reported to modulate lipid raft-dependent signaling, but not yet lipid raft-dependent oxidative stress. Previously, we have shown that ethanol-induced membrane remodeling, i.e., an increase in membrane fluidity and alterations in physical and biochemical properties of lipid rafts, participated in the development of oxidative stress. Thus, we decided to study n-3 PUFA effects in this context, by pretreating hepatocytes with eicosapentaenoic acid (EPA), a long-chain n-3 PUFA, before addition of ethanol. EPA was found to increase ethanol-induced oxidative stress through membrane remodeling. Addition of EPA resulted in a marked increase in lipid raft aggregation compared to ethanol alone. In addition, membrane fluidity of lipid rafts was markedly enhanced. Interestingly, EPA was found to preferentially incorporate into nonraft membrane regions, leading to raft cholesterol increase. Lipid raft aggregation by EPA enhanced phospholipase Cγ translocation into these microdomains. Finally, phospholipase Cγ was shown to participate in the potentiation of oxidative stress by promoting lysosome accumulation, a major source of low-molecular-weight iron. To conclude, the ability of EPA to modify lipid raft physical and chemical properties plays a key role in the enhancement, by this dietary n-3 PUFA, of ethanol-induced oxidative stress.
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Affiliation(s)
- Fatiha Aliche-Djoudi
- EA 4427 SeRAIC/IRSET, IFR 140, UFR des Sciences Pharmaceutiques et Biologiques, Université de Rennes 1, Rennes Cédex, France
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72
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Shaikh SR. Biophysical and biochemical mechanisms by which dietary N-3 polyunsaturated fatty acids from fish oil disrupt membrane lipid rafts. J Nutr Biochem 2011; 23:101-5. [PMID: 22137258 DOI: 10.1016/j.jnutbio.2011.07.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 07/08/2011] [Accepted: 07/11/2011] [Indexed: 12/11/2022]
Abstract
N-3 polyunsaturated fatty acids (PUFAs) from fish oil exert their functional effects by targeting multiple mechanisms. One mechanism to emerge in the past decade is the ability of n-3 PUFA acyl chains to perturb the molecular organization of plasma membrane sphingolipid/cholesterol-enriched lipid raft domains. These domains are nanometer-scale assemblies that coalesce to compartmentalize select proteins for optimal function. Here we review recent evidence on how n-3 PUFAs modify lipid rafts from biophysical and biochemical experiments from several different model systems. A central theme emerges from these studies. N-3 PUFA acyl chains display tremendous conformational flexibility and a low affinity for cholesterol and saturated acyl chains. This unique flexibility of n-3 PUFA acyl chains impacts the organization of inner and outer leaflet lipid rafts by disrupting acyl chain packing and molecular order within rafts. Ultimately, the disruption in raft organization has consequences for protein clustering and thereby signaling. Overall, elucidating the complex mechanisms by which n-3 PUFA acyl chains reorganize membrane architecture will enhance the translation of these fatty acids into the clinic for treating several diseases.
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Affiliation(s)
- Saame Raza Shaikh
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA.
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73
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Yajima T, Inoue R, Yajima M, Tsuruta T, Karaki S, Hira T, Kuwahara A. The G-protein on cholesterol-rich membrane microdomains mediates mucosal sensing of short- chain fatty acid and secretory response in rat colon. Acta Physiol (Oxf) 2011; 203:381-9. [PMID: 21649864 DOI: 10.1111/j.1748-1716.2011.02331.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIM Short-chain fatty acids (SCFA) stimulate colonic contraction and secretion, which are mediated by an enteric reflex via a mucosal sensing and cholinergic mechanisms. The involvement of G-protein signal transduction was examined in the secretory response to luminal propionate sensing in rat distal colon. METHODS Mucosa-submucosa and mucosa preparations were used to measure short-circuit current (I(sc)) and acetylcholine (ACh) release respectively. Cholesterol-rich membrane microdomains, lipid rafts/caveolae, were fractionated using a sucrose gradient ultra-centrifugation after detergent-free extraction of the isolated colonic crypt. RESULTS Luminal addition of methyl-β-cyclodextrin (10 mm) and mastoparan (30 μm), lipid rafts/caveolae disruptors, significantly inhibited luminal propionate-induced (0.5 mm) increases in I(sc) , but did not affect increases in I(sc) induced by serosal ACh (0.05 mm) or electrical field stimulation (EFS). Luminal addition of YM-254890 (10 μm), a Gα(q/11) -selective inhibitor, markedly inhibited propionate-induced increase in I(sc) , but did not affect I(sc) responses to ACh and EFS. Both methyl-β-cyclodextrin and YM-254890 significantly inhibited luminal propionate-induced non-neuronal release of ACh from colonocytes. Real-time PCR demonstrated that in mRNA expression of SCFA receptors, GPR 43 was far higher than that of GPR41 in the colon. Western blotting analysis revealed that the cholesterol-rich membrane microdomains that fractionated from colonic crypt cells were associated with caveolin-1, flotillin-1 and Gα(q/11) , but not GPR43. Uncoupling of Gα(q/11) from flotillin-1 in lipid rafts occurred under desensitization of the I(sc) response to propionate. CONCLUSIONS These data demonstrate that the secretory response to luminal propionate in rat colon is mediated by G-protein on cholesterol-rich membrane microdomains, provably via Gα(q/11) .
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Affiliation(s)
- T Yajima
- Meiji Dairies Research Chair, Creative Research Institution, Hokkaido University, Sapporo, Japan.
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74
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Shaikh SR, Jolly CA, Chapkin RS. n-3 Polyunsaturated fatty acids exert immunomodulatory effects on lymphocytes by targeting plasma membrane molecular organization. Mol Aspects Med 2011; 33:46-54. [PMID: 22020145 DOI: 10.1016/j.mam.2011.10.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 10/04/2011] [Accepted: 10/09/2011] [Indexed: 01/26/2023]
Abstract
Fish oil, enriched in bioactive n-3 polyunsaturated fatty acids (PUFA), has therapeutic value for the treatment of inflammation-associated disorders. The effects of n-3 PUFAs are pleiotropic and complex; hence, an understanding of their cellular targets and molecular mechanisms of action remains incomplete. Here we focus on recent data indicating n-3 PUFAs exert immunosuppressive effects on the function of effector and regulatory CD4(+) T cells. In addition, we also present emerging evidence that n-3 PUFAs have immunomodulatory effects on B cells. We then focus on one multifaceted mechanism of n-3 PUFAs, which is the alteration of the biophysical and biochemical organization of the plasma membrane. This mechanism is central for downstream signaling, eicosanoid production, transcriptional regulation and cytokine secretion. We highlight recent work demonstrating n-3 PUFA acyl chains in the plasma membrane target the lateral organization of membrane signaling assemblies (i.e. lipid rafts or signaling networks) and de novo phospholipid biosynthesis. We conclude by proposing new functional and mechanistic questions in this area of research that will aid in the development of fish oil as adjuvant therapy for treating unresolved chronic inflammation.
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Affiliation(s)
- Saame Raza Shaikh
- Department of Biochemistry & Molecular Biology and East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA.
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75
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Zhao G, Subbaiah PV, Mintzer E, Chiu SW, Jakobsson E, Scott HL. Molecular dynamic simulation study of cholesterol and conjugated double bonds in lipid bilayers. Chem Phys Lipids 2011; 164:811-8. [PMID: 21982866 DOI: 10.1016/j.chemphyslip.2011.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 01/23/2023]
Abstract
Conjugated linoleic acids (CLA) are found naturally in dairy products. Two isomers of CLA, that differ only in the location of cis and trans double bonds, are found to have distinct and different biological effects. The cis 9 trans 11 (C9T11) isomer is believed to have anti-carcinogenic effects, while the trans 10 cis 12 (T10C12) isomer is believed to be associated with anti-obesity effects. In this paper we extend earlier molecular dynamics (MD) simulations of pure CLA-phosphatidylcholine bilayers to investigate the comparative effects of cholesterol on bilayers composed of the two respective isomers. Simulations of phosphatidylcholine lipid bilayers in which the sn-2 chains contained one of the two isomers of CLA were performed in which, for each isomer, the simulated bilayers contained 10% and 30% cholesterol (Chol). From MD trajectories we calculate and compare structural properties of the bilayers, including areas per molecule, thickness of bilayers, tilt angle of cholesterols, order parameter profiles, and one and two-dimensional radial distribution function (RDF), as functions of Chol concentration. While the structural effect of cholesterol is approximately the same for both isomers, we find differences at an atomistic level in order parameter profiles and in two-dimensional radial distribution functions.
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Affiliation(s)
- Guijun Zhao
- Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
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76
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Different subcellular populations of L-type Ca2+ channels exhibit unique regulation and functional roles in cardiomyocytes. J Mol Cell Cardiol 2011; 52:376-87. [PMID: 21888911 DOI: 10.1016/j.yjmcc.2011.08.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/11/2011] [Accepted: 08/17/2011] [Indexed: 11/23/2022]
Abstract
Influx of Ca(2+) through L-type Ca(2+) channels (LTCCs) contributes to numerous cellular processes in cardiomyocytes including excitation-contraction (EC) coupling, membrane excitability, and transcriptional regulation. Distinct subpopulations of LTCCs have been identified in cardiac myocytes, including those at dyadic junctions and within different plasma membrane microdomains such as lipid rafts and caveolae. These subpopulations of LTCCs exhibit regionally distinct functional properties and regulation, affording precise spatiotemporal modulation of L-type Ca(2+) current (I(Ca,L)). Different subcellular LTCC populations demonstrate variable rates of Ca(2+)-dependent inactivation and sometimes coupled gating of neighboring channels, which can lead to focal, persistent I(Ca,L). In addition, the assembly of spatially defined macromolecular signaling complexes permits compartmentalized regulation of I(Ca,L) by a variety of neurohormonal pathways. For example, β-adrenergic receptor subtypes signal to different LTCC subpopulations, with β(2)-adrenergic activation leading to enhanced I(Ca,L) through caveolar LTCCs and β(1)-adrenergic stimulation modulating LTCCs outside of caveolae. Disruptions in the normal subcellular targeting of LTCCs and associated signaling proteins may contribute to the pathophysiology of a variety of cardiac diseases including heart failure and certain arrhythmias. Further identifying the characteristic functional properties and array of regulatory molecules associated with specific LTCC subpopulations will provide a mechanistic framework to understand how LTCCs contribute to diverse cellular processes in normal and diseased myocardium. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
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77
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McMurray DN, Bonilla DL, Chapkin RS. n-3 Fatty acids uniquely affect anti-microbial resistance and immune cell plasma membrane organization. Chem Phys Lipids 2011; 164:626-35. [PMID: 21798252 DOI: 10.1016/j.chemphyslip.2011.07.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/20/2011] [Accepted: 07/11/2011] [Indexed: 12/18/2022]
Abstract
It is now well established that dietary lipids are incorporated into macrophage and T-cell membrane microdomains, altering their structure and function. Within cell membranes, there are specific detergent-resistant domains in which key signal transduction proteins are localized. These regions are classified as "lipid rafts". Rafts are composed mostly of cholesterol and sphingolipids and therefore do not integrate well into the fluid phospholipid bilayers causing them to form microdomains. Upon cell activation, rafts compartmentalize signal-transducing molecules, thus providing an environment conducive to signal transduction. In this review, we discuss recent novel data describing the effects of n-3 PUFA on alterations in the activation and functions of macrophages and T-cells. We believe that the modifications in these two disparate immune cell types are linked by fundamentally similar changes in membrane lipid composition and transmembrane signaling functions. We conclude that the outcomes of n-3 PUFA-mediated immune cell alterations may be beneficial (e.g., anti-inflammatory) or detrimental (e.g., loss of microbial immunity) depending upon the cell type interrogated.
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Affiliation(s)
- David N McMurray
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, TX 77843-1313, USA.
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78
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Larson MK, Shearer GC, Ashmore JH, Anderson-Daniels JM, Graslie EL, Tholen JT, Vogelaar JL, Korth AJ, Nareddy V, Sprehe M, Harris WS. Omega-3 fatty acids modulate collagen signaling in human platelets. Prostaglandins Leukot Essent Fatty Acids 2011; 84:93-8. [PMID: 21177087 PMCID: PMC3031726 DOI: 10.1016/j.plefa.2010.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 10/26/2010] [Accepted: 11/14/2010] [Indexed: 01/19/2023]
Abstract
Dietary intake of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) results in cardioprotective benefits. However, the cellular and physiological bases for these benefits remain unclear. We hypothesized that EPA and DHA treatments would interfere with collagen-mediated platelet signaling. Thirty healthy volunteers received 28 days of 3.4 g/d EPA+DHA with and without a single dose of aspirin. Clinical hematologic parameters were then measured along with assays of collagen-stimulated platelet activation and protein phosphorylation. Omega-3 therapy led to a small but significant reduction in platelets (6.3%) and red blood cells (1.7%), but did not impair clinical time-to-closure assays. However, collagen-mediated platelet signaling events of integrin activation, α-granule secretion, and phosphatidylserine exposure were all reduced by roughly 50% after omega-3 incorporation, and collagen-induced tyrosine phosphorylation was significantly impaired. The diminished platelet response to collagen may account for some of the cardioprotective benefits provided by DHA and EPA.
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Affiliation(s)
- M K Larson
- Biology Department, Augustana College, Sioux Falls, SD 57197, USA.
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79
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Zhao G, Subbaiah PV, Chiu SW, Jakobsson E, Scott HL. Conjugated double bonds in lipid bilayers: a molecular dynamics simulation study. Chem Phys Lipids 2011; 164:251-7. [PMID: 21320475 DOI: 10.1016/j.chemphyslip.2011.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 02/03/2011] [Accepted: 02/04/2011] [Indexed: 11/16/2022]
Abstract
Conjugated linoleic acids (CLA) are found naturally in dairy products. Two isomers of CLA, that differ only in the location of cis and trans double bonds, are found to have distinct and different biological effects. The cis 9 trans 11 (C9T11) isomer is attributed to have the anti-carcinogenic effects, while the trans 10 cis 12 (T10C12) isomer is believed to be responsible for the anti-obesity effects. Since dietary CLA are incorporated into membrane phospholipids, we have used Molecular Dynamics (MD) simulations to investigate the comparative effects of the two isomers on lipid bilayer structure. Specifically, simulations of phosphatidylcholine lipid bilayers in which the sn-2 chains contained one of the two isomers of CLA were performed. Force field parameters for the torsional potential of double bonds were obtained from ab initio calculations. From the MD trajectories we calculated and compared structural properties of the two lipid bilayers, including areas per molecule, density profiles, thickness of bilayers, tilt angle of tail chains, order parameters profiles, radial distribution function (RDF) and lateral pressure profiles. The main differences found between bilayers of the two CLA isomers, are (1) the order parameter profile for C9T11 has a dip in the middle of sn-2 chain while the profile for T10C12 has a deeper dip close to terminal of sn-2 chain, and (2) the lateral pressure profiles show differences between the two isomers. Our simulation results reveal localized physical structural differences between bilayers of the two CLA isomers that may contribute to different biological effects through differential interactions with membrane proteins or cholesterol.
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Affiliation(s)
- Guijun Zhao
- Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, 60616, United States
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80
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Majkova Z, Toborek M, Hennig B. The role of caveolae in endothelial cell dysfunction with a focus on nutrition and environmental toxicants. J Cell Mol Med 2011; 14:2359-70. [PMID: 20406324 PMCID: PMC2965309 DOI: 10.1111/j.1582-4934.2010.01064.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Complications of vascular diseases, including atherosclerosis, are the number one cause of death in Western societies. Dysfunction of endothelial cells is a critical underlying cause of the pathology of atherosclerosis. Lipid rafts, and especially caveolae, are enriched in endothelial cells, and down-regulation of the caveolin-1 gene may provide protection against the development of atherosclerosis. There is substantial evidence that exposure to environmental pollution is linked to cardiovascular mortality, and that persistent organic pollutants can markedly contribute to endothelial cell dysfunction and an increase in vascular inflammation. Nutrition can modulate the toxicity of environmental pollutants, and evidence suggests that these affect health and disease outcome associated with chemical insults. Because caveolae can provide a regulatory platform for pro-inflammatory signalling associated with vascular diseases such as atherosclerosis, we suggest a link between atherogenic risk and functional changes of caveolae by environmental factors such as dietary lipids and organic pollutants. For example, we have evidence that endothelial caveolae play a role in uptake of persistent organic pollutants, an event associated with subsequent production of inflammatory mediators. Functional properties of caveolae can be modulated by nutrition, such as dietary lipids (e.g. fatty acids) and plant-derived polyphenols (e.g. flavonoids), which change activation of caveolae-associated signalling proteins. The following review will focus on caveolae providing a platform for pro-inflammatory signalling, and the role of caveolae in endothelial cell functional changes associated with environmental mediators such as nutrients and toxicants, which are known to modulate the pathology of vascular diseases.
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Affiliation(s)
- Zuzana Majkova
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY, USA
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81
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Caveolae: a regulatory platform for nutritional modulation of inflammatory diseases. J Nutr Biochem 2011; 22:807-11. [PMID: 21292468 DOI: 10.1016/j.jnutbio.2010.09.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 09/13/2010] [Accepted: 09/30/2010] [Indexed: 12/18/2022]
Abstract
Dietary intervention strategies have proven to be an effective means of decreasing several risk factors associated with the development of atherosclerosis. Endothelial cell dysfunction influences vascular inflammation and is involved in promoting the earliest stages of lesion formation. Caveolae are lipid raft microdomains abundant within the plasma membrane of endothelial cells and are responsible for modulating receptor-mediated signal transduction, thus influencing endothelial activation. Caveolae have been implicated in the regulation of enzymes associated with several key signaling pathways capable of determining intracellular redox status. Diet and plasma-derived nutrients may modulate an inflammatory outcome by interacting with and altering caveolae-associated cellular signaling. For example, omega-3 fatty acids and several polyphenolics have been shown to improve endothelial cell function by decreasing the formation of ROS and increasing NO bioavailability, events associated with altered caveolae composition. Thus, nutritional modulation of caveolae-mediated signaling events may provide an opportunity to ameliorate inflammatory signaling pathways capable of promoting the formation of vascular diseases, including atherosclerosis.
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82
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Tajima N, Itokazu Y, Korpi ER, Somerharju P, Käkelä R. Activity of BK(Ca) channel is modulated by membrane cholesterol content and association with Na+/K+-ATPase in human melanoma IGR39 cells. J Biol Chem 2010; 286:5624-38. [PMID: 21135099 DOI: 10.1074/jbc.m110.149898] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interaction of large conductance Ca(2+)- and voltage-activated K(+) (BK(Ca)) channels with Na(+)/K(+)-ATPase, caveolin-1, and cholesterol was studied in human melanoma IGR39 cells. Functional BK(Ca) channels were enriched in caveolin-rich and detergent-resistant membranes, i.e. rafts, and blocking of the channels by a specific BK(Ca) blocker paxilline reduced proliferation of the cells. Disruption of rafts by selective depletion of cholesterol released BK(Ca) channels from these domains with a consequent increase in their activity. Consistently, cholesterol enrichment of the cells increased the proportion of BK(Ca) channels in rafts and decreased their activity. Immunocytochemical analysis showed that BK(Ca) channels co-localize with Na(+)/K(+)-ATPase in a cholesterol-dependent manner, thus suggesting their co-presence in rafts. Supporting this, ouabain, a specific blocker of Na(+)/K(+)-ATPase, inhibited BK(Ca) whole-cell current markedly in control cells but not in cholesterol-depleted ones. This inhibition required the presence of external Na(+). Collectively, these data indicate that the presence of Na(+)/K(+)-ATPase in rafts is essential for efficient functioning of BK(Ca) channels, presumably because the pump maintains a low intracellular Na(+) proximal to the BK(Ca) channel. In conclusion, cholesterol could play an important role in cellular ion homeostasis and thus modulate many cellular functions and cell proliferation.
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Affiliation(s)
- Nobuyoshi Tajima
- Department of Medical Biochemistry and Developmental Biology, Institute of Biomedicine, University of Helsinki, Helsinki FI-00014, Finland
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83
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Fiaccavento R, Carotenuto F, Vecchini A, Binaglia L, Forte G, Capucci E, Maccari AM, Minieri M, Di Nardo P. An omega-3 fatty acid-enriched diet prevents skeletal muscle lesions in a hamster model of dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2176-84. [PMID: 20829440 DOI: 10.2353/ajpath.2010.100174] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Currently, despite well-known mutational causes, a universal treatment for neuromuscular disorders is still lacking, and current therapeutic efforts are mainly restricted to symptomatic treatments. In the present study, δ-sarcoglycan-null dystrophic hamsters were fed a diet enriched in flaxseed-derived ω3 α-linolenic fatty acid from weaning until death. α-linolenic fatty acid precluded the dystrophic degeneration of muscle morphology and function. In fact, in dystrophic animals fed flaxseed-derived α-linolenic fatty acid, the histological appearance of the muscular tissue was improved, the proliferation of interstitial cells was decreased, and the myogenic differentiation originated new myocytes to repair the injured muscle. In addition, muscle myofibers were larger and cell membrane integrity was preserved, as witnessed by the correct localization of α-, β-, and γ-sarcoglycans and α-dystroglycan. Furthermore, the cytoplasmic accumulation of both β-catenin and caveolin-3 was abolished in dystrophic hamster muscle fed α-linolenic fatty acid versus control animals fed standard diet, while α-myosin heavy chain was expressed at nearly physiological levels. These findings, obtained by dietary intervention only, introduce a novel concept that provides evidence that the modulation of the plasmalemma lipid profile could represent an efficacious strategy to ameliorate human muscular dystrophy.
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Affiliation(s)
- Roberta Fiaccavento
- Laboratorio di Cardiologia Molecolare e Cellulare, Dipartimento di Medicina Interna, Università di Roma Tor Vergata, Via Montpellier, 1, 00133 Roma, Italy
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84
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Adkins Y, Kelley DS. Mechanisms underlying the cardioprotective effects of omega-3 polyunsaturated fatty acids. J Nutr Biochem 2010; 21:781-92. [DOI: 10.1016/j.jnutbio.2009.12.004] [Citation(s) in RCA: 362] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 12/01/2009] [Accepted: 12/03/2009] [Indexed: 12/11/2022]
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85
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Matesanz N, Park G, McAllister H, Leahey W, Devine A, McVeigh GE, Gardiner TA, McDonald DM. Docosahexaenoic acid improves the nitroso-redox balance and reduces VEGF-mediated angiogenic signaling in microvascular endothelial cells. Invest Ophthalmol Vis Sci 2010; 51:6815-25. [PMID: 20702831 DOI: 10.1167/iovs.10-5339] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Disturbances to the cellular production of nitric oxide (NO) and superoxide (O(2)(-)) can have deleterious effects on retinal vascular integrity and angiogenic signaling. Dietary agents that could modulate the production of these signaling molecules from their likely enzymatic sources, endothelial nitric oxide synthase (eNOS) and NADPH oxidase, would therefore have a major beneficial effect on retinal vascular disease. The effect of ω-3 polyunsaturated fatty acids (PUFAs) on angiogenic signaling and NO/superoxide production in retinal microvascular endothelial cells (RMECs) was investigated. METHODS Primary RMECs were treated with docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) for 48 hours. RMEC migration was determined by scratch-wound assay, proliferation by the incorporation of BrdU, and angiogenic sprouting using a three-dimensional model of in vitro angiogenesis. NO production was quantified by Griess assay, and phospho-eNOS accumulation and superoxide were measured using the fluorescent probe dihydroethidine. eNOS localization to caveolin-rich microdomains was determined by Western blot analysis after subfractionation on a linear sucrose gradient. RESULTS DHA treatment increased nitrite and decreased superoxide production, which correlated with the displacement of eNOS from caveolar subdomains and colocalization with the negative regulator caveolin-1. In addition, both ω-3 PUFAs demonstrated reduced responsiveness to VEGF-stimulated superoxide and nitrite release and significantly impaired endothelial wound healing, proliferation, and angiogenic sprout formation. CONCLUSIONS DHA improves NO bioavailability, decreases O(2)(-) production, and blunts VEGF-mediated angiogenic signaling. These findings suggest a role for ω-3 PUFAs, particularly DHA, in maintaining vascular integrity while reducing pathologic retinal neovascularization.
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Affiliation(s)
- Nuria Matesanz
- Centre for Vision and Vascular Science, Queen's University Belfast, Northern Ireland, United Kingdom
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86
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Flaxseed oil–trastuzumab interaction in breast cancer. Food Chem Toxicol 2010; 48:2223-6. [DOI: 10.1016/j.fct.2010.05.052] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 04/28/2010] [Accepted: 05/18/2010] [Indexed: 11/18/2022]
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87
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Ye S, Tan L, Ma J, Shi Q, Li J. Polyunsaturated docosahexaenoic acid suppresses oxidative stress induced endothelial cell calcium influx by altering lipid composition in membrane caveolar rafts. Prostaglandins Leukot Essent Fatty Acids 2010; 83:37-43. [PMID: 20206488 DOI: 10.1016/j.plefa.2010.02.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Revised: 01/22/2010] [Accepted: 02/02/2010] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To determine whether DHA suppresses oxidative stress induced endothelial cell calcium influx by altering lipid composition and TRPC1 distribution in membrane rafts. METHODS Endothelial cells (EC) were pretreated with DHA or stearic acid, then incubated for another 3h with media containing H(2)O(2). Membrane lipid rafts were isolated using the discontinuous sucrose density gradient ultracentrifugation method. Intracellular calcium was detected with laser scanning confocal microscope. TRPC1 protein in membrane fractions was detected by immunoblotting. Membrane fatty acids compositions were analyzed by gas chromatography; raft cholesterol level was assayed by an Amplex Red Cholesterol Assay kit, and DAG concentration was quantified by a DAG kinase assay. RESULTS DHA significantly reduced oxidative stress induced calcium influx; pretreated with DHA the n-3 PUFAs were significantly increased in raft fractions, as well as saturated myristic acid, palmitic acid content of membrane rafts in EC; while the stearic acid, monounsaturated oleic acid and cis-oleic acid were decreased. Incubation with DHA also significantly reduced the amount of SM and cholesterol levels in the raft. Interestingly, we fractioned plasma membrane subcellular compartments and discovered that certain amounts of TRPC1 existed in detergent-resistant plasma membrane fractions of EC. After DHA treatment, TRPC1 was partly displaced from lipid raft to detergent-soluble membrane fractions. CONCLUSIONS DHA significantly reduces oxidative stress induced endothelial calcium influx, this effect might be associated with, at least in part, altered raft lipid environment, and suppresses TRPC1-mediated calcium signaling pathway by partially displacing TRPC1 from membrane caveolar lipid rafts.
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Affiliation(s)
- Sheng Ye
- Institute of Hepatobiliary Surgery, Chinese PLA General Hospital, Beijing 100853, China.
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88
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Huot PS, Sarkar B, Ma DW. Conjugated linoleic acid alters caveolae phospholipid fatty acid composition and decreases caveolin-1 expression in MCF-7 breast cancer cells. Nutr Res 2010; 30:179-85. [DOI: 10.1016/j.nutres.2010.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 02/25/2010] [Accepted: 02/26/2010] [Indexed: 12/30/2022]
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89
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Kello M, Mikeš J, Jendželovský R, Kovaľ J, Fedoročko P. PUFAs enhance oxidative stress and apoptosis in tumour cells exposed to hypericin-mediated PDT. Photochem Photobiol Sci 2010; 9:1244-51. [DOI: 10.1039/c0pp00085j] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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90
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Bozza PT, D’Avila H, Almeida PE, Magalhães KG, Molinaro R, Almeida CJ, Maya-Monteiro CM. Lipid droplets in host–pathogen interactions. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/clp.09.63] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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91
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Davidson LA, Wang N, Shah MS, Lupton JR, Ivanov I, Chapkin RS. n-3 Polyunsaturated fatty acids modulate carcinogen-directed non-coding microRNA signatures in rat colon. Carcinogenesis 2009; 30:2077-84. [PMID: 19825969 PMCID: PMC2792315 DOI: 10.1093/carcin/bgp245] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 09/04/2009] [Accepted: 09/30/2009] [Indexed: 12/13/2022] Open
Abstract
We have hypothesized that dietary modulation of intestinal non-coding RNA [microRNA (miRNA)] expression may contribute to the chemoprotective effects of nutritional bioactives (fish oil and pectin). To fully understand the effects of these agents on the expression of miRNAs, Sprague-Dawley rats were fed diets containing corn oil or fish oil with pectin or cellulose and injected with azoxymethane (AOM, a colon-specific carcinogen) or saline (control). Real-time polymerase chain reaction using miRNA-specific primers and Taq Man probes was carried out to quantify effects on miRNA expression in colonic mucosa. From 368 mature miRNAs assayed, at an early stage of cancer progression (10 week post AOM injection), let-7d, miR-15b, miR-107, miR-191 and miR-324-5p were significantly (P < 0.05) affected by diet x carcinogen interactions. Overall, fish oil fed animals exhibited the smallest number of differentially expressed miRNAs (AOM versus saline treatment). With respect to the tumor stage (34 week post AOM injection), 46 miRNAs were dysregulated in adenocarcinomas compared with normal mucosa from saline-injected animals. Of the 27 miRNAs expressed at higher (P < 0.05) levels in tumors, miR-34a, 132, 223 and 224 were overexpressed at >10-fold. In contrast, the expression levels of miR-192, 194, 215 and 375 were dramatically reduced (< or = 0.32-fold) in adenocarcinomas. These results demonstrate for the first time the utility of the rat AOM model and the novel role of fish oil in protecting the colon from carcinogen-induced miRNA dysregulation.
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Affiliation(s)
- Laurie A. Davidson
- Program in Integrative Nutrition & Complex Diseases
- Center for Environmental and Rural Health
| | | | - Manasvi S. Shah
- Program in Integrative Nutrition & Complex Diseases
- Intercollegiate Faculty of Genetics
| | - Joanne R. Lupton
- Program in Integrative Nutrition & Complex Diseases
- Center for Environmental and Rural Health
| | - Ivan Ivanov
- Center for Environmental and Rural Health
- Department of Veterinary Physiology & Pharmacology
| | - Robert S. Chapkin
- Program in Integrative Nutrition & Complex Diseases
- Center for Environmental and Rural Health
- Intercollegiate Faculty of Genetics
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, TX 77843, USA
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92
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Shaikh SR, Locascio DS, Soni SP, Wassall SR, Stillwell W. Oleic- and docosahexaenoic acid-containing phosphatidylethanolamines differentially phase separate from sphingomyelin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2421-6. [PMID: 19735642 DOI: 10.1016/j.bbamem.2009.08.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 08/22/2009] [Accepted: 08/31/2009] [Indexed: 10/20/2022]
Abstract
A central tenet of the lipid raft model is the existence of non-raft domains. In support of this view, we have established in model membranes that a phosphatidylethanolamine (PE)-containing docosahexaenoic acid (DHA) forms organizationally distinct non-raft domains in the presence of sphingomyelin (SM) and cholesterol (Chol). We have shown that formation of DHA-rich domains is driven by unfavorable molecular interactions between the rigid Chol molecule and the highly flexible DHA acyl chain. However, the molecular interactions between SM and the DHA-containing PE, which could also contribute to the formation of DHA-rich non-raft domains, have not been sufficiently investigated. To address this issue, we use differential scanning calorimetry (DSC) to study the phase behavior of mixtures of SM with either 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphoethanolamine (16:0-22:6PE) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (16:0-18:1PE), an oleic acid (OA)-containing control, over a wide range of concentrations. Deconvolution of binary DSC scans shows that both 16:0-22:6PE and 16:0-18:1PE phase separate from SM. Analysis of transition temperatures and partial phase diagrams, constructed from the DSC scans for the first time, shows that 16:0-22:6PE displays greater non-ideal mixing with SM compared to 16:0-18:1PE. Our findings support a model in which DHA- and OA-containing PEs differentially phase separate from SM over a wide range of molar ratios to initiate the formation of non-raft domains, which is greatly enhanced by DHA, but not OA, in the presence of cholesterol.
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Affiliation(s)
- Saame Raza Shaikh
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA.
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93
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Anderson BM, Ma DWL. Are all n-3 polyunsaturated fatty acids created equal? Lipids Health Dis 2009; 8:33. [PMID: 19664246 PMCID: PMC3224740 DOI: 10.1186/1476-511x-8-33] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 08/10/2009] [Indexed: 12/14/2022] Open
Abstract
N-3 Polyunsaturated fatty acids have been shown to have potential beneficial effects for chronic diseases including cancer, insulin resistance and cardiovascular disease. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in particular have been studied extensively, whereas substantive evidence for a biological role for the precursor, alpha-linolenic acid (ALA), is lacking. It is not enough to assume that ALA exerts effects through conversion to EPA and DHA, as the process is highly inefficient in humans. Thus, clarification of ALA's involvement in health and disease is essential, as it is the principle n-3 polyunsaturated fatty acid consumed in the North American diet and intakes of EPA and DHA are typically very low. There is evidence suggesting that ALA, EPA and DHA have specific and potentially independent effects on chronic disease. Therefore, this review will assess our current understanding of the differential effects of ALA, EPA and DHA on cancer, insulin resistance, and cardiovascular disease. Potential mechanisms of action will also be reviewed. Overall, a better understanding of the individual role for ALA, EPA and DHA is needed in order to make appropriate dietary recommendations regarding n-3 polyunsaturated fatty acid consumption.
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Affiliation(s)
- Breanne M Anderson
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario N1G2W1 Canada.
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94
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Chapkin RS, Kim W, Lupton JR, McMurray DN. Dietary docosahexaenoic and eicosapentaenoic acid: emerging mediators of inflammation. Prostaglandins Leukot Essent Fatty Acids 2009; 81:187-91. [PMID: 19502020 PMCID: PMC2755221 DOI: 10.1016/j.plefa.2009.05.010] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The inflammatory response is designed to help fight and clear infection, remove harmful chemicals, and repair damaged tissue and organ systems. Although this process, in general, is protective, the failure to resolve the inflammation and return the target tissue to homeostasis can result in disease, including the promotion of cancer. A plethora of published literature supports the contention that dietary n-3 polyunsaturated fatty acids (PUFA), and eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) in particular, are important modulators of a host's inflammatory/immune responses. The following review describes a mechanistic model that may explain, in part, the pleiotropic anti-inflammatory and immunosuppressive properties of EPA and DHA. In this review, we focus on salient studies that address three overarching mechanisms of n-3 PUFA action: (i) modulation of nuclear receptor activation, i.e., nuclear factor-kappaB (NF-kappaB) suppression; (ii) suppression of arachidonic acid-cyclooxygenase-derived eicosanoids, primarily prostaglandin E(2)-dependent signaling; and (iii) alteration of the plasma membrane micro-organization (lipid rafts), particularly as it relates to the function of Toll-like receptors (TLRs), and T-lymphocyte signaling molecule recruitment to the immunological synapse (IS). We propose that lipid rafts may be targets for the development of n-3 PUFA-containing dietary bioactive agents to down-modulate inflammatory and immune responses and for the treatment of autoimmune and chronic inflammatory diseases.
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Affiliation(s)
- Robert S Chapkin
- Department of Nutrition and Food Science, Faculty of Nutrition, Kleberg Biotechnology Center, MS 2253, Texas A&M University, College Station, TX 77843-2253, USA.
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95
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Escrich E, Solanas M, Moral R, Costa I, Grau L. Are the olive oil and other dietary lipids related to cancer? Experimental evidence. Clin Transl Oncol 2009; 8:868-83. [PMID: 17169760 DOI: 10.1007/s12094-006-0150-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
There is a wealth of evidence supporting the relationship between dietary lipids and cancer, particularly those of the breast, colon and rectum and prostate. The main support comes from the international correlational studies and, especially, from experimental ones. The evidence from human analytical studies is less consistent because of several conflicting findings, probably due to methodological issues. Experimentally, it has been clearly demonstrated that quantity and type of dietary lipids as well as the particular critical phases of the carcinogenesis in which they act, are the essential factors in this relationship. Thus, whereas high dietary intake of n-6 polyunsaturated fatty acids (PUFA), primarily LA, and saturated fat has tumor-enhancing effects, long chain n-3 PUFA, CLA and GLA have inhibitory effects. Monounsaturated fatty acids (MUFA), mainly OA, present in high quantities in olive oil, seem to be protective although some inconsistent results have been reported. Bioactive compounds of virgin olive oil may also account for the protective effect of this oil, which is the main source of fat in the Mediterranean diet. Experimental studies have also provided evidence of several putative mechanisms of action of dietary lipids on cancer. Lipids can influence the hormonal status, modify cell membranes structure and function, cell signalling transduction pathways and gene expression, and modulate the function of the immune system. Although further studies are needed to evaluate and verify these mechanisms in humans, based on the multiple ways dietary lipids can act, they may have an important influence on tumorigenesis.
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Affiliation(s)
- E Escrich
- Department of Cell Biology, Physiology and Immunology, Physiology Unit, Faculty of Medicine, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.
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96
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Balijepalli RC, Kamp TJ. Caveolae, ion channels and cardiac arrhythmias. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2009; 98:149-60. [PMID: 19351512 DOI: 10.1016/j.pbiomolbio.2009.01.012] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Caveolae are specialized membrane microdomains enriched in cholesterol and sphingolipids which are present in multiple cell types including cardiomyocytes. Along with the essential scaffolding protein caveolin-3, a number of different ion channels and transporters have been localized to caveolae in cardiac myocytes including L-type Ca2+ channels (Ca(v)1.2), Na+ channels (Na(v)1.5), pacemaker channels (HCN4), Na+/Ca2+ exchanger (NCX1) and others. Closely associated with these channels are specific macromolecular signaling complexes that provide highly localized regulation of the channels. Mutations in the caveolin-3 gene (CAV3) have been linked with the congenital long QT syndrome (LQT9), and mutations in caveolar-localized ion channels may contribute to other inherited arrhythmias. Changes in the caveolar microdomain in acquired heart disease may also lead to dysregulation and dysfunction of ion channels, altering the risk of arrhythmias in conditions such as heart failure. This review highlights the existing evidence identifying and characterizing ion channels localized to caveolae in cardiomyocytes and their role in arrhythmogenesis.
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Affiliation(s)
- Ravi C Balijepalli
- Department of Medicine, Cellular and Molecular Arrhythmia Research Program, University of Wisconsin, Madison, WI 53792, USA
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97
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Experimental models and mechanisms underlying the protective effects of n-3 polyunsaturated fatty acids in Alzheimer's disease. J Nutr Biochem 2009; 20:1-10. [DOI: 10.1016/j.jnutbio.2008.05.016] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 05/07/2008] [Accepted: 05/21/2008] [Indexed: 11/19/2022]
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98
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Kim W, Chapkin RS, Barhoumi R, Ma DWL. A novel role for nutrition in the alteration of functional microdomains on the cell surface. Methods Mol Biol 2009; 579:261-70. [PMID: 19763480 DOI: 10.1007/978-1-60761-322-0_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Membrane rafts are ordered microdomains of the plasma membrane consisting of cholesterol, sphingolipids, and saturated fatty acids which appear to regulate many cellular signaling pathways. One such type of membrane raft is caveolae, which are cave-like invaginations of the plasma membrane. Interestingly, changes in the acyl composition of cellular membranes have been shown to alter the specific localization of membrane raft associated proteins and their function. This is noteworthy because modification of membrane acyl composition is readily accomplished through changes in dietary fat composition. Here we describe a common approach used to fractionate cell membranes to obtain an enriched preparation of caveolae and gas chromatographic techniques to determine fatty acyl composition. In addition, methods used to visualize and quantify lipid rafts using a fluorescent probe Laurdan in living cells will also be described.
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Affiliation(s)
- Wooki Kim
- Department of Nutritional Sciences, University of Toronto Faculty of Medicine, Toronto, ON, Canada
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99
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Wang L, Lim EJ, Toborek M, Hennig B. The role of fatty acids and caveolin-1 in tumor necrosis factor alpha-induced endothelial cell activation. Metabolism 2008; 57:1328-39. [PMID: 18803934 PMCID: PMC3349996 DOI: 10.1016/j.metabol.2008.01.036] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 01/31/2008] [Indexed: 12/27/2022]
Abstract
Hypertriglyceridemia and associated high circulating free fatty acids are important risk factors for atherosclerosis. In contrast to omega-3 fatty acids, linoleic acid, the major omega-6 unsaturated fatty acid in the American diet, may be atherogenic by amplifying an endothelial inflammatory response. We hypothesize that omega-6 and omega-3 fatty acids can differentially modulate tumor necrosis factor alpha (TNF-alpha)-induced endothelial cell activation and that functional plasma membrane microdomains called caveolae are required for endothelial cell activation. Caveolae are particularly abundant in endothelial cells and play a major role in endothelial trafficking and the regulation of signaling pathways associated with the pathology of vascular diseases. To test our hypothesis, endothelial cells were preenriched with either linoleic acid or alpha-linolenic acid before TNF-alpha-induced endothelial activation. Measurements included oxidative stress and nuclear factor kappaB-dependent induction of cyclooxygenase-2 (COX-2) and prostaglandin E(2) (PGE(2)) under experimental conditions with intact caveolae and with cells in which caveolin-1 was silenced by small interfering RNA. Exposure to TNF-alpha induced oxidative stress and inflammatory mediators, such as p38 mitogen-activated protein kinase (MAPK), nuclear factor kappaB, COX-2, and PGE(2), which were all amplified by preenrichment with linoleic acid but blocked or reduced by alpha-linolenic acid. The p38 MAPK inhibitor SB203580 blocked TNF-alpha-mediated induction of COX-2 protein expression, suggesting a regulatory mechanism through p38 MAPK signaling. Image overlay demonstrated TNF-alpha-induced colocalization of TNF receptor type 1 with caveolin-1. Caveolin-1 was significantly induced by TNF-alpha, which was further amplified by linoleic acid and blocked by alpha-linolenic acid. Furthermore, silencing of the caveolin-1 gene completely blocked TNF-alpha-induced production of COX-2 and PGE(2) and significantly reduced the amplified response of linoleic acid plus TNF-alpha. These data suggest that omega-6 and omega-3 fatty acids can differentially modulate TNF-alpha-induced inflammatory stimuli and that caveolae and its fatty acid composition play a regulatory role during TNF-alpha-induced endothelial cell activation and inflammation.
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Affiliation(s)
- Lei Wang
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington KY 40536, USA
- Molecular and Cell Nutrition Laboratory, College of Agriculture, University of Kentucky, Lexington KY 40536, USA
| | - Eun-Jin Lim
- Molecular and Cell Nutrition Laboratory, College of Agriculture, University of Kentucky, Lexington KY 40536, USA
| | - Michal Toborek
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington KY 40536, USA
- Department of Neurosurgery, University of Kentucky, Lexington KY 40536, USA
| | - Bernhard Hennig
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington KY 40536, USA
- Graduate Center for Toxicology, University of Kentucky, Lexington KY 40536, USA
- Molecular and Cell Nutrition Laboratory, College of Agriculture, University of Kentucky, Lexington KY 40536, USA
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100
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Bate C, Tayebi M, Diomede L, Salmona M, Williams A. Docosahexaenoic and eicosapentaenoic acids increase prion formation in neuronal cells. BMC Biol 2008; 6:39. [PMID: 18789130 PMCID: PMC2556658 DOI: 10.1186/1741-7007-6-39] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 09/12/2008] [Indexed: 12/12/2022] Open
Abstract
Background The transmissible spongiform encephalopathies, otherwise known as prion diseases, occur following the conversion of the cellular prion protein (PrPC) to an alternatively folded, disease-associated isoform (PrPSc). Recent studies suggest that this conversion occurs via a cholesterol-sensitive process, as cholesterol synthesis inhibitors reduced the formation of PrPSc and delayed the clinical phase of scrapie infection. Since polyunsaturated fatty acids also reduced cellular cholesterol levels we tested their effects on PrPSc formation in three prion-infected neuronal cell lines (ScGT1, ScN2a and SMB cells). Results We report that treatment with docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) or the cholesterol synthesis inhibitor simvastatin reduced the amounts of free cholesterol in membrane extracts from prion-infected neuronal cells. Simvastatin reduced cholesterol production while DHA and EPA promoted the conversion of free cholesterol to cholesterol esters. Crucially, while simvastatin reduced PrPSc formation, both DHA and EPA significantly increased the amounts of PrPSc in these cells. Unlike simvastatin, the effects of DHA and EPA on PrPSc content were not reversed by stimulation of cholesterol synthesis with mevalonate. Treatment of ScGT1 cells with DHA and EPA also increased activation of cytoplasmic phospholipase A2 and prostaglandin E2 production. Finally, treatment of neuronal cells with DHA and EPA increased the amounts of PrPC expressed at the cell surface and significantly increased the half-life of biotinylated PrPC. Conclusion We report that although treatment with DHA or EPA significantly reduced the free cholesterol content of prion-infected cells they significantly increased PrPSc formation in three neuronal cell lines. DHA or EPA treatment of infected cells increased activation of phospholipase A2, a key enzyme in PrPSc formation, and altered the trafficking of PrPC. PrPC expression at the cell surface, a putative site for the PrPSc formation, was significantly increased, and the rate at which PrPC was degraded was reduced. Cholesterol depletion is seen as a potential therapeutic strategy for prion diseases. However, these results indicate that a greater understanding of the precise relationship between membrane cholesterol distribution, PrPC trafficking, cell activation and PrPSc formation is required before cholesterol manipulation can be considered as a prion therapeutic.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts, UK, AL9 7TA.
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