51
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Murphy EJ. The blood-brain barrier and protein-mediated fatty acid uptake: role of the blood-brain barrier as a metabolic barrier. J Neurochem 2017; 141:324-329. [DOI: 10.1111/jnc.14000] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 02/23/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Eric J. Murphy
- Department of Biomedical Sciences; School of Medicine and Health Sciences; University of North Dakota; Grand Forks North Dakota USA
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52
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Cifre M, Díaz-Rúa R, Varela-Calviño R, Reynés B, Pericás-Beltrán J, Palou A, Oliver P. Human peripheral blood mononuclear cell in vitro system to test the efficacy of food bioactive compounds: Effects of polyunsaturated fatty acids and their relation with BMI. Mol Nutr Food Res 2016; 61. [PMID: 27873461 DOI: 10.1002/mnfr.201600353] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 11/14/2016] [Accepted: 11/17/2016] [Indexed: 01/04/2023]
Abstract
SCOPE To analyse the usefulness of isolated human peripheral blood mononuclear cells (PBMC) to rapidly/easily reflect n-3 long-chain polyunsaturated fatty acid (LCPUFA) effects on lipid metabolism/inflammation gene profile, and evaluate if these effects are body mass index (BMI) dependent. METHODS AND RESULTS PBMC from normoweight (NW) and overweight/obese (OW/OB) subjects were incubated with physiological doses of docosahexaenoic (DHA), eicosapentaenoic acid (EPA), or their combination. PBMC reflected increased beta-oxidation-like capacity (CPT1A expression) in OW/OB but only after DHA treatment. However, insensitivity to n-3 LCPUFA was evident in OW/OB for lipogenic genes: both PUFA diminished FASN and SREBP1C expression in NW, but no effect was observed for DHA in PBMC from high-BMI subjects. This insensitivity was also evident for inflammation gene profile: all treatments inhibited key inflammatory genes in NW; nevertheless, no effect was observed in OW/OB after DHA treatment, and EPA effect was impaired. SLC27A2, IL6 and TNFα PBMC expression analysis resulted especially interesting to determine obesity-related n-3 LCPUFA insensitivity. CONCLUSION A PBMC-based human in vitro system reflects n-3 LCPUFA effects on lipid metabolism/inflammation which is impaired in OW/OB. These results confirm the utility of PBMC ex vivo systems for bioactive-compound screening to promote functional food development and to establish appropriate dietary strategies for obese population.
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Affiliation(s)
- Margalida Cifre
- Laboratory of Molecular Biology, Nutrition and Biotechnology, Universitat de les Illes Balears and CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Palma de Mallorca, Spain
| | - Rubén Díaz-Rúa
- Laboratory of Molecular Biology, Nutrition and Biotechnology, Universitat de les Illes Balears and CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Palma de Mallorca, Spain
| | - Rubén Varela-Calviño
- Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Bàrbara Reynés
- Laboratory of Molecular Biology, Nutrition and Biotechnology, Universitat de les Illes Balears and CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Palma de Mallorca, Spain
| | - Jordi Pericás-Beltrán
- Research Group on Evidence, Lifestyles & Health, Universitat de les Illes Balears, Palma de Mallorca, Spain
| | - Andreu Palou
- Laboratory of Molecular Biology, Nutrition and Biotechnology, Universitat de les Illes Balears and CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Palma de Mallorca, Spain
| | - Paula Oliver
- Laboratory of Molecular Biology, Nutrition and Biotechnology, Universitat de les Illes Balears and CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn), Palma de Mallorca, Spain
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53
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Yan S, Xu M, Wang R, Li Q, Yu Z, Xie J. Overexpression of Rv2788 increases mycobacterium stresses survival. Microbiol Res 2016; 195:51-59. [PMID: 28024526 DOI: 10.1016/j.micres.2016.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 11/18/2022]
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis-one of the most devastating infectious diseases, is a successful intracellular pathogen capable of surviving diverse stresses. Unveiling the molecular mechanisms governing this superior adaptation will inspire better control measures against tuberculosis. To define the role of Rv2788, a manganese-dependent transcriptional repressor, M.smegmatis was used as the host strain for heterologous expression Rv2788. Rv2788 can significantly change the colony morphology and fatty acids and permeability of cell wall, enhance the growth of the recombinants and resistance to diverse stresses, such as hydrogen peroxide (H₂O₂), diamide exposure, surface stress, acidic condition, multiple antibiotics treatment including chloramphenicol, vancomycin and amikacin. The dysregulation of the target genes of Rv2788, such as whiB1 and lexA, might underpin such phenotypes. The results implicate important roles of Rv2788 in the survival of Mycobacterium under stresses, and might represent ideal novel antibiotics target candidate.
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Affiliation(s)
- Shuangquan Yan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Mengmeng Xu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Rui Wang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Qiming Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Zhaoxiao Yu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Enviroment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
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Santucci P, Bouzid F, Smichi N, Poncin I, Kremer L, De Chastellier C, Drancourt M, Canaan S. Experimental Models of Foamy Macrophages and Approaches for Dissecting the Mechanisms of Lipid Accumulation and Consumption during Dormancy and Reactivation of Tuberculosis. Front Cell Infect Microbiol 2016; 6:122. [PMID: 27774438 PMCID: PMC5054039 DOI: 10.3389/fcimb.2016.00122] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 09/22/2016] [Indexed: 12/11/2022] Open
Abstract
Despite a slight decline since 2014, tuberculosis (TB) remains the major deadly infectious disease worldwide with about 1.5 million deaths each year and with about one-third of the population being latently infected with Mycobacterium tuberculosis, the etiologic agent of TB. During primo-infection, the recruitment of immune cells leads to the formation of highly organized granulomas. Among the different cells, one outstanding subpopulation is the foamy macrophage (FM), characterized by the abundance of triacylglycerol-rich lipid bodies (LB). M. tuberculosis can reside in FM, where it acquires, from host LB, the neutral lipids which are subsequently processed and stored by the bacilli in the form of intracytosolic lipid inclusions (ILI). Although host LB can be viewed as a reservoir of nutrients for the pathogen during latency, the molecular mechanisms whereby intraphagosomal mycobacteria interact with LB and assimilate the LB-derived lipids are only beginning to be understood. Past studies have emphasized that these physiological processes are critical to the M. tuberculosis infectious-life cycle, for propagation of the infection, establishment of the dormancy state and reactivation of the disease. In recent years, several animal and cellular models have been developed with the aim of dissecting these complex processes and of determining the nature and contribution of their key players. Herein, we review some of the in vitro and in vivo models which allowed to gain significant insight into lipid accumulation and consumption in M. tuberculosis, two important events that are directly linked to pathogenicity, granuloma formation/maintenance and survival of the tubercle bacillus under non-replicative conditions. We also discuss the advantages and limitations of each model, hoping that this will serve as a guide for future investigations dedicated to persistence and innovative therapeutic approaches against TB.
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Affiliation(s)
- Pierre Santucci
- Aix-Marseille Université, Centre National de la Recherche Scientifique, EIPL Marseille, France
| | - Feriel Bouzid
- Aix-Marseille Université, Centre National de la Recherche Scientifique, EIPLMarseille, France; Aix-Marseille Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, URMITEMarseille, France
| | - Nabil Smichi
- Aix-Marseille Université, Centre National de la Recherche Scientifique, EIPLMarseille, France; Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Centre National de la Recherche Scientifique FRE3689, Université de MontpellierMontpellier, France
| | - Isabelle Poncin
- Aix-Marseille Université, Centre National de la Recherche Scientifique, EIPL Marseille, France
| | - Laurent Kremer
- Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Centre National de la Recherche Scientifique FRE3689, Université de MontpellierMontpellier, France; Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, Institut National de la Santé et de la Recherche MédicaleMontpellier, France
| | - Chantal De Chastellier
- Aix-Marseille Université, Centre National de la Recherche Scientifique, EIPL Marseille, France
| | - Michel Drancourt
- Aix-Marseille Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de Recherche pour le Développement, URMITE Marseille, France
| | - Stéphane Canaan
- Aix-Marseille Université, Centre National de la Recherche Scientifique, EIPL Marseille, France
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55
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Huo X, Wu B, Feng M, Han B, Fang Y, Hao Y, Meng L, Wubie AJ, Fan P, Hu H, Qi Y, Li J. Proteomic Analysis Reveals the Molecular Underpinnings of Mandibular Gland Development and Lipid Metabolism in Two Lines of Honeybees (Apis mellifera ligustica). J Proteome Res 2016; 15:3342-57. [DOI: 10.1021/acs.jproteome.6b00526] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Xinmei Huo
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Bin Wu
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Mao Feng
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Bin Han
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Yu Fang
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Yue Hao
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Lifeng Meng
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Abebe Jenberie Wubie
- Department
of Animal production and Technology, College of Agriculture and Environmental
Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Pei Fan
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Han Hu
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Yuping Qi
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
| | - Jianke Li
- Institute
of Apicultural Research/Key Laboratory of Pollinating Insect Biology,
Ministry of Agriculture, Chinese Academy of Agricultural Science, Beijing 100093, China
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56
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Dongiovanni P, Valenti L. Genetics of nonalcoholic fatty liver disease. Metabolism 2016; 65:1026-37. [PMID: 26409295 DOI: 10.1016/j.metabol.2015.08.018] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/23/2015] [Accepted: 08/26/2015] [Indexed: 02/07/2023]
Abstract
UNLABELLED Epidemiological, familial, and twin studies indicate that non-alcoholic fatty liver disease, now the leading cause of liver damage in developed countries, has a strong heritability. The common I148M variant of PNPLA3 impairing hepatocellular lipid droplets remodeling is the major genetic determinant of hepatic fat content. The I148M variant has a strong impact on the full spectrum of liver damage related to fatty liver, encompassing non-alcoholic steatohepatitis, advanced fibrosis, and hepatocellular carcinoma, and influences the response to therapeutic approaches. Common variants in GCKR enhance de novo hepatic lipogenesis in response to glucose and liver inflammation. Furthermore, the low-frequency E167K variant of TM6SF2 and rare mutations in APOB, which impair very low-density lipoproteins secretion, predispose to progressive fatty liver. CONCLUSIONS These and other recent findings reviewed here indicate that impaired lipid handling by hepatocytes has a major role in the pathogenesis of non-alcoholic fatty liver disease by triggering inflammation, fibrogenesis, and carcinogenesis. These discoveries have provided potential novel biomarkers for clinical use and have revealed intriguing therapeutic targets.
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Affiliation(s)
- Paola Dongiovanni
- Internal Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
| | - Luca Valenti
- Internal Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico; Department of Pathophysiology and Transplantation, Università degli Studi Milano, Milan, Italy.
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57
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Snook LA, Wright DC, Holloway GP. Postprandial control of fatty acid transport proteins' subcellular location is not dependent on insulin. FEBS Lett 2016; 590:2661-70. [PMID: 27311759 DOI: 10.1002/1873-3468.12260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/28/2016] [Accepted: 06/14/2016] [Indexed: 01/09/2023]
Abstract
Fatty acid transport proteins rapidly translocate to the plasma membrane in response to various stimuli, including insulin, influencing lipid uptake into muscle. However, our understanding of the mechanisms regulating postprandial fatty acid transporter subcellular location remains limited. We demonstrate that the response of fatty acid transporters to insulin stimulation is extremely brief and not temporally matched in the postprandial state. We further show that high-fat diet-induced accumulation of fatty acid transporters on the plasma membrane can occur in the absence of insulin. Altogether, these data suggest that insulin is not the primary signal regulating fatty acid transporter relocation in vivo.
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Affiliation(s)
- Laelie A Snook
- Department of Human Health and Nutritional Sciences, University of Guelph, Canada
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, Canada
| | - Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Canada
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58
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Anstee QM, Seth D, Day CP. Genetic Factors That Affect Risk of Alcoholic and Nonalcoholic Fatty Liver Disease. Gastroenterology 2016; 150:1728-1744.e7. [PMID: 26873399 DOI: 10.1053/j.gastro.2016.01.037] [Citation(s) in RCA: 166] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/17/2016] [Accepted: 01/20/2016] [Indexed: 02/07/2023]
Abstract
Genome-wide association studies and candidate gene studies have informed our understanding of factors contributing to the well-recognized interindividual variation in the progression and outcomes of alcoholic liver disease and nonalcoholic fatty liver disease. We discuss the mounting evidence for shared modifiers and common pathophysiological processes that contribute to development of both diseases. We discuss the functions of proteins encoded by risk variants of genes including patatin-like phospholipase domain-containing 3 and transmembrane 6 superfamily member 2, as well as epigenetic factors that contribute to the pathogenesis of alcoholic liver disease and nonalcoholic fatty liver disease. We also discuss important areas of future genetic research and their potential to affect clinical management of patients.
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Affiliation(s)
- Quentin M Anstee
- Liver Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle-upon-Tyne, United Kingdom.
| | - Devanshi Seth
- Centenary Institute of Cancer Medicine, Royal Prince Alfred Hospital, Camperdown, Australia; Drug Health Services, Royal Prince Alfred Hospital, Camperdown, Australia; Central Clinical School, The University of Sydney, Camperdown, Australia
| | - Christopher P Day
- Liver Research Group, Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle-upon-Tyne, United Kingdom
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Metabolic reprogramming through fatty acid transport protein 1 (FATP1) regulates macrophage inflammatory potential and adipose inflammation. Mol Metab 2016; 5:506-526. [PMID: 27408776 PMCID: PMC4921943 DOI: 10.1016/j.molmet.2016.04.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 04/08/2016] [Accepted: 04/18/2016] [Indexed: 12/22/2022] Open
Abstract
Objective A novel approach to regulate obesity-associated adipose inflammation may be through metabolic reprogramming of macrophages (MΦs). Broadly speaking, MΦs dependent on glucose are pro-inflammatory, classically activated MΦs (CAM), which contribute to adipose inflammation and insulin resistance. In contrast, MΦs that primarily metabolize fatty acids are alternatively activated MΦs (AAM) and maintain tissue insulin sensitivity. In actuality, there is much flexibility and overlap in the CAM-AAM spectrum in vivo dependent upon various stimuli in the microenvironment. We hypothesized that specific lipid trafficking proteins, e.g. fatty acid transport protein 1 (FATP1), would direct MΦ fatty acid transport and metabolism to limit inflammation and contribute to the maintenance of adipose tissue homeostasis. Methods Bone marrow derived MΦs (BMDMs) from Fatp1−/− and Fatp1+/+ mice were used to investigate FATP1-dependent substrate metabolism, bioenergetics, metabolomics, and inflammatory responses. We also generated C57BL/6J chimeric mice by bone marrow transplant specifically lacking hematopoetic FATP1 (Fatp1B−/−) and controls Fatp1B+/+. Mice were challenged by high fat diet (HFD) or low fat diet (LFD) and analyses including MRI, glucose and insulin tolerance tests, flow cytometric, histologic, and protein quantification assays were conducted. Finally, an FATP1-overexpressing RAW 264.7 MΦ cell line (FATP1-OE) and empty vector control (FATP1-EV) were developed as a gain of function model to test effects on substrate metabolism, bioenergetics, metabolomics, and inflammatory responses. Results Fatp1 is downregulated with pro-inflammatory stimulation of MΦs. Fatp1−/− BMDMs and FATP1-OE RAW 264.7 MΦs demonstrated that FATP1 reciprocally controled metabolic flexibility, i.e. lipid and glucose metabolism, which was associated with inflammatory response. Supporting our previous work demonstrating the positive relationship between glucose metabolism and inflammation, loss of FATP1 enhanced glucose metabolism and exaggerated the pro-inflammatory CAM phenotype. Fatp1B−/− chimeras fed a HFD gained more epididymal white adipose mass, which was inflamed and oxidatively stressed, compared to HFD-fed Fatp1B+/+ controls. Adipose tissue macrophages displayed a CAM-like phenotype in the absence of Fatp1. Conversely, functional overexpression of FATP1 decreased many aspects of glucose metabolism and diminished CAM-stimulated inflammation in vitro. FATP1 displayed acyl-CoA synthetase activity for long chain fatty acids in MΦs and modulated lipid mediator metabolism in MΦs. Conclusion Our findings provide evidence that FATP1 is a novel regulator of MΦ activation through control of substrate metabolism. Absence of FATP1 exacerbated pro-inflammatory activation in vitro and increased local and systemic components of the metabolic syndrome in HFD-fed Fatp1B−/− mice. In contrast, gain of FATP1 activity in MΦs suggested that Fatp1-mediated activation of fatty acids, substrate switch to glucose, oxidative stress, and lipid mediator synthesis are potential mechanisms. We demonstrate for the first time that FATP1 provides a unique mechanism by which the inflammatory tone of adipose and systemic metabolism may be regulated. FATP1-mediated activation of fatty acids is a novel approach to limit inflammation. Fatp1 deficiency primed macrophages for pro-inflammatory activation. Lack of Fatp1 led to greater HFD-induced adipose inflammation. Fatp1−/− adipose tissue macrophages were classically activated.
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60
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Jayewardene AF, Mavros Y, Reeves A, Hancock DP, Gwinn T, Rooney KB. Interactions Between Fatty Acid Transport Proteins, Genes That Encode for Them, and Exercise: A Systematic Review. J Cell Physiol 2016; 231:1671-87. [PMID: 26638980 DOI: 10.1002/jcp.25281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 12/04/2015] [Indexed: 01/29/2023]
Abstract
Long-chain fatty acid (LCFA) movement into skeletal muscle involves a highly mediated process in which lipid rafts are utilized in the cellular membrane, involving numerous putative plasma membrane-associated LCFA transport proteins. The process of LCFA uptake and oxidation is of particular metabolic significance both at rest and during light to moderate exercise. A comprehensive systematic search of electronic databases was conducted to investigate whether exercise alters protein and/or gene expression of putative LCFA transport proteins. There were 31 studies meeting all eligibility criteria, of these 13 utilized an acute exercise protocol and 18 examined chronic exercise adaptations. Seventeen involved a study design incorporating an exercise stimulus, while the remaining 14 incorporated a combined exercise and diet stimulus. Divergent data relating to acute exercise, as well as prolonged exercise training (≥3 weeks), on protein content (PC) response was identified for proteins CD36, FABPpm and CAV1. Messenger ribonucleic acid (mRNA) data did not always correspond to functional PC, supporting previous suggestions of a disconnect due to potentially limiting factors post gene expression. The large array of study designs, cohorts, and primary dependent variables within the studies included in the present review elucidate the complexity of the interaction between exercise and LCFA transport proteins. Summary of the results in the present review validate the need for further targeted investigation within this topic, and provide an important information base for such research. J. Cell. Physiol. 231: 1671-1687, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Avindra F Jayewardene
- Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales, Australia
| | - Yorgi Mavros
- Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales, Australia
| | - Anneliese Reeves
- Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales, Australia
| | - Dale P Hancock
- School of Molecular Biosciences, Faculty of Science, University of Sydney, Camperdown, New South Wales, Australia
| | - Tom Gwinn
- Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales, Australia
| | - Kieron B Rooney
- Discipline of Exercise and Sport Science, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales, Australia
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61
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Combined defects in oxidative phosphorylation and fatty acid β-oxidation in mitochondrial disease. Biosci Rep 2016; 36:BSR20150295. [PMID: 26839416 PMCID: PMC4793296 DOI: 10.1042/bsr20150295] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/02/2016] [Indexed: 12/20/2022] Open
Abstract
Mitochondria provide the main source of energy to eukaryotic cells, oxidizing fats and sugars to generate ATP. Mitochondrial fatty acid β-oxidation (FAO) and oxidative phosphorylation (OXPHOS) are two metabolic pathways which are central to this process. Defects in these pathways can result in diseases of the brain, skeletal muscle, heart and liver, affecting approximately 1 in 5000 live births. There are no effective therapies for these disorders, with quality of life severely reduced for most patients. The pathology underlying many aspects of these diseases is not well understood; for example, it is not clear why some patients with primary FAO deficiencies exhibit secondary OXPHOS defects. However, recent findings suggest that physical interactions exist between FAO and OXPHOS proteins, and that these interactions are critical for both FAO and OXPHOS function. Here, we review our current understanding of the interactions between FAO and OXPHOS proteins and how defects in these two metabolic pathways contribute to mitochondrial disease pathogenesis.
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62
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Macaluso FS, Maida M, Petta S. Genetic background in nonalcoholic fatty liver disease: A comprehensive review. World J Gastroenterol 2015; 21:11088-11111. [PMID: 26494964 PMCID: PMC4607907 DOI: 10.3748/wjg.v21.i39.11088] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/11/2015] [Accepted: 09/02/2015] [Indexed: 02/06/2023] Open
Abstract
In the Western world, nonalcoholic fatty liver disease (NAFLD) is considered as one of the most significant liver diseases of the twenty-first century. Its development is certainly driven by environmental factors, but it is also regulated by genetic background. The role of heritability has been widely demonstrated by several epidemiological, familial, and twin studies and case series, and likely reflects the wide inter-individual and inter-ethnic genetic variability in systemic metabolism and wound healing response processes. Consistent with this idea, genome-wide association studies have clearly identified Patatin-like phosholipase domain-containing 3 gene variant I148M as a major player in the development and progression of NAFLD. More recently, the transmembrane 6 superfamily member 2 E167K variant emerged as a relevant contributor in both NAFLD pathogenesis and cardiovascular outcomes. Furthermore, numerous case-control studies have been performed to elucidate the potential role of candidate genes in the pathogenesis and progression of fatty liver, although findings are sometimes contradictory. Accordingly, we performed a comprehensive literature search and review on the role of genetics in NAFLD. We emphasize the strengths and weaknesses of the available literature and outline the putative role of each genetic variant in influencing susceptibility and/or progression of the disease.
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63
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Ahowesso C, Black PN, Saini N, Montefusco D, Chekal J, Malosh C, Lindsley CW, Stauffer SR, DiRusso CC. Chemical inhibition of fatty acid absorption and cellular uptake limits lipotoxic cell death. Biochem Pharmacol 2015; 98:167-81. [PMID: 26394026 DOI: 10.1016/j.bcp.2015.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/03/2015] [Indexed: 12/31/2022]
Abstract
Chronic elevation of plasma free fatty acid (FFA) levels is commonly associated with obesity, type 2 diabetes, cardiovascular disease and some cancers. Experimental evidence indicates FFA and their metabolites contribute to disease development through lipotoxicity. Previously, we identified a specific fatty acid transport inhibitor CB16.2, a.k.a. Lipofermata, using high throughput screening methods. In this study, efficacy of transport inhibition was measured in four cell lines that are models for myocytes (mmC2C12), pancreatic β-cells (rnINS-1E), intestinal epithelial cells (hsCaco-2), and hepatocytes (hsHepG2), as well as primary human adipocytes. The compound was effective in inhibiting uptake with IC50s between 3 and 6μM for all cell lines except human adipocytes (39μM). Inhibition was specific for long and very long chain fatty acids but had no effect on medium chain fatty acids (C6-C10), which are transported by passive diffusion. Derivatives of Lipofermata were evaluated to understand structural contributions to activity. Lipofermata prevented palmitate-mediated oxidative stress, induction of BiP and CHOP, and cell death in a dose-dependent manner in hsHepG2 and rnINS-1E cells, suggesting it will prevent induction of fatty acid-mediated cell death pathways and lipotoxic disease by channeling excess fatty acids to adipose tissue and away from liver and pancreas. Importantly, mice dosed orally with Lipofermata were not able to absorb (13)C-oleate demonstrating utility as an inhibitor of fatty acid absorption from the gut.
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Affiliation(s)
- Constance Ahowesso
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Paul N Black
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Nipun Saini
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - David Montefusco
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Jessica Chekal
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States
| | - Chrysa Malosh
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, United States; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States
| | - Shaun R Stauffer
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, United States; Vanderbilt Specialized Chemistry Center for Probe Development (MLPCN), Nashville, TN 37232, United States; Department of Chemistry, Vanderbilt University, Nashville, TN 37232, United States
| | - Concetta C DiRusso
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0664, United States.
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Genetic Factors in the Pathogenesis of Nonalcoholic Fatty Liver and Steatohepatitis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:460190. [PMID: 26273621 PMCID: PMC4530215 DOI: 10.1155/2015/460190] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 12/18/2014] [Indexed: 02/06/2023]
Abstract
Liver fat accumulation generally related to systemic insulin resistance characterizes nonalcoholic fatty liver disease (NAFLD), which in the presence of nonalcoholic steatohepatitis (NASH) can progress towards cirrhosis and hepatocellular carcinoma. Due to the epidemic of obesity, NAFLD is now the most frequent liver disease in Western countries. Epidemiological, familial, and twin studies provide evidence for a strong genetic component of NAFLD susceptibility. Recently, genome-wide association studies led to the identification of the major inherited determinants of hepatic fat accumulation: patatin-like phospholipase domain-containing 3 (PNPLA3) I148M gene and transmembrane 6 superfamily member 2 (TM6SF2) E167K gene variants, involved in lipid droplets remodelling and very low-density lipoproteins secretion, are the major determinants of interindividual differences in liver steatosis, and susceptibility to progressive NASH. In this review, we aimed to provide an overview of recent insights into the genetics of hepatic fat accumulation and steatohepatitis.
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65
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Luo H, Zeng J, Huang Q, Liu M, Abdalla AE, Xie L, Wang H, Xie J. Mycobacterium tuberculosisRv1265 promotes mycobacterial intracellular survival and alters cytokine profile of the infected macrophage. J Biomol Struct Dyn 2015; 34:585-99. [DOI: 10.1080/07391102.2015.1046935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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66
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Monaco C, Whitfield J, Jain SS, Spriet LL, Bonen A, Holloway GP. Activation of AMPKα2 Is Not Required for Mitochondrial FAT/CD36 Accumulation during Exercise. PLoS One 2015; 10:e0126122. [PMID: 25965390 PMCID: PMC4429092 DOI: 10.1371/journal.pone.0126122] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/30/2015] [Indexed: 12/30/2022] Open
Abstract
Exercise has been shown to induce the translocation of fatty acid translocase (FAT/CD36), a fatty acid transport protein, to both plasma and mitochondrial membranes. While previous studies have examined signals involved in the induction of FAT/CD36 translocation to sarcolemmal membranes, to date the signaling events responsible for FAT/CD36 accumulation on mitochondrial membranes have not been investigated. In the current study muscle contraction rapidly increased FAT/CD36 on plasma membranes (7.5 minutes), while in contrast, FAT/CD36 only increased on mitochondrial membranes after 22.5 minutes of muscle contraction, a response that was exercise-intensity dependent. Considering that previous research has shown that AMP activated protein kinase (AMPK) α2 is not required for FAT/CD36 translocation to the plasma membrane, we investigated whether AMPK α2 signaling is necessary for mitochondrial FAT/CD36 accumulation. Administration of 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) induced AMPK phosphorylation, and resulted in FAT/CD36 accumulation on SS mitochondria, suggesting AMPK signaling may mediate this response. However, SS mitochondrial FAT/CD36 increased following acute treadmill running in both wild-type (WT) and AMPKα 2 kinase dead (KD) mice. These data suggest that AMPK signaling is not required for SS mitochondrial FAT/CD36 accumulation. The current data also implicates alternative signaling pathways that are exercise-intensity dependent, as IMF mitochondrial FAT/CD36 content only occurred at a higher power output. Taken altogether the current data suggests that activation of AMPK signaling is sufficient but not required for exercise-induced accumulation in mitochondrial FAT/CD36.
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Affiliation(s)
- Cynthia Monaco
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Jamie Whitfield
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Swati S. Jain
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Lawrence L. Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Arend Bonen
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Graham P. Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
- * E-mail:
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67
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Obesity and cancer progression: is there a role of fatty acid metabolism? BIOMED RESEARCH INTERNATIONAL 2015; 2015:274585. [PMID: 25866768 PMCID: PMC4383231 DOI: 10.1155/2015/274585] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 11/24/2014] [Indexed: 12/30/2022]
Abstract
Currently, there is renewed interest in elucidating the metabolic characteristics of cancer and how these characteristics may be exploited as therapeutic targets. Much attention has centered on glucose, glutamine and de novo lipogenesis, yet the metabolism of fatty acids that arise from extracellular, as well as intracellular, stores as triacylglycerol has received much less attention. This review focuses on the key pathways of fatty acid metabolism, including uptake, esterification, lipolysis, and mitochondrial oxidation, and how the regulators of these pathways are altered in cancer. Additionally, we discuss the potential link that fatty acid metabolism may serve between obesity and changes in cancer progression.
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68
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Inoue M, Akama T, Jiang Y, Chun TH. The exocyst complex regulates free fatty acid uptake by adipocytes. PLoS One 2015; 10:e0120289. [PMID: 25768116 PMCID: PMC4359155 DOI: 10.1371/journal.pone.0120289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 02/03/2015] [Indexed: 11/19/2022] Open
Abstract
The exocyst is an octameric molecular complex that drives vesicle trafficking in adipocytes, a rate-limiting step in insulin-dependent glucose uptake. This study assessed the role of the exocyst complex in regulating free fatty acid (FFA) uptake by adipocytes. Upon differentiating into adipocytes, 3T3-L1 cells acquire the ability to incorporate extracellular FFAs in an insulin-dependent manner. A kinetic assay using fluoresceinated FFA (C12 dodecanoic acid) uptake allows the real-time monitoring of FFA internalization by adipocytes. The insulin-dependent uptake of C12 dodecanoic acid by 3T3-L1 adipocytes is mediated by Akt and phosphatidylinositol 3 (PI3)-kinase. Gene silencing of the exocyst components Exo70 and Sec8 significantly reduced insulin-dependent FFA uptake by adipocytes. Consistent with the roles played by Exo70 and Sec8 in FFA uptake, mCherry-tagged Exo70 and HA-tagged Sec8 partially colocalize with lipid droplets within adipocytes, suggesting their active roles in the development of lipid droplets. Tubulin polymerization was also found to regulate FFA uptake in collaboration with the exocyst complex. This study demonstrates a novel role played by the exocyst complex in the regulation of FFA uptake by adipocytes.
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Affiliation(s)
- Mayumi Inoue
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Takeshi Akama
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Yibin Jiang
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Tae-Hwa Chun
- Division of Metabolism, Endocrinology & Diabetes (MEND), Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
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69
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Chen CT, Bazinet RP. β-oxidation and rapid metabolism, but not uptake regulate brain eicosapentaenoic acid levels. Prostaglandins Leukot Essent Fatty Acids 2015; 92:33-40. [PMID: 24986271 DOI: 10.1016/j.plefa.2014.05.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The brain has a unique polyunsaturated fatty acid composition, with high levels of arachidonic and docosahexaenoic acids (DHA) while levels of eicosapentaenoic acid (EPA) are several orders of magnitude lower. As evidence accumulated that fatty acid entry into the brain was not selective and, in fact, that DHA and EPA enter the brain at similar rates, new mechanisms were required to explain their large concentration differences in the brain. Here we summarize recent research demonstrating that EPA is rapidly and extensively β-oxidized upon entry into the brain. Although the ATP generated from the β-oxidation of EPA is low compared to the use of glucose, fatty acid β-oxidation may serve to regulate brain fatty acid levels in the absence of selective transportation. Furthermore, when β-oxidation of EPA is blocked, desaturation of EPA increases and Land׳s recycling decreases to maintain low EPA levels.
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Affiliation(s)
- Chuck T Chen
- Department of Nutritional Sciences, University of Toronto, Fitzgerald Building, 150 College St. Room 306, Ontario, Toronto, M5S 3E2 Canada
| | - Richard P Bazinet
- Department of Nutritional Sciences, University of Toronto, Fitzgerald Building, 150 College St. Room 306, Ontario, Toronto, M5S 3E2 Canada.
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70
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Daniel J, Sirakova T, Kolattukudy P. An acyl-CoA synthetase in Mycobacterium tuberculosis involved in triacylglycerol accumulation during dormancy. PLoS One 2014; 9:e114877. [PMID: 25490545 PMCID: PMC4260918 DOI: 10.1371/journal.pone.0114877] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/14/2014] [Indexed: 11/17/2022] Open
Abstract
Latent infection with dormant Mycobacterium tuberculosis is one of the major reasons behind the emergence of drug-resistant strains of the pathogen worldwide. In its dormant state, the pathogen accumulates lipid droplets containing triacylglycerol synthesized from fatty acids derived from host lipids. In this study, we show that Rv1206 (FACL6), which is annotated as an acyl-CoA synthetase and resembles eukaryotic fatty acid transport proteins, is able to stimulate fatty acid uptake in E. coli cells. We show that purified FACL6 displays acyl-coenzyme A synthetase activity with a preference towards oleic acid, which is one of the predominant fatty acids in host lipids. Our results indicate that the expression of FACL6 protein in Mycobacterium tuberculosis is significantly increased during in vitro dormancy. The facl6-deficient Mycobacterium tuberculosis mutant displayed a diminished ability to synthesize acyl-coenzyme A in cell-free extracts. Furthermore, during in vitro dormancy, the mutant synthesized lower levels of intracellular triacylglycerol from exogenous fatty acids. Complementation partially restored the lost function. Our results suggest that FACL6 modulates triacylglycerol accumulation as the pathogen enters dormancy by activating fatty acids.
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Affiliation(s)
- Jaiyanth Daniel
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida, 32816, United States of America; Department of Biology, Indiana University-Purdue University Fort Wayne, Fort Wayne, Indiana, 46805, United States of America
| | - Tatiana Sirakova
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida, 32816, United States of America
| | - Pappachan Kolattukudy
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida, 32816, United States of America
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71
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Lin MH, Miner JH. Fatty acid transport protein 1 can compensate for fatty acid transport protein 4 in the developing mouse epidermis. J Invest Dermatol 2014; 135:462-470. [PMID: 25184958 PMCID: PMC4289464 DOI: 10.1038/jid.2014.378] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 11/18/2022]
Abstract
Fatty acid transport protein (FATP) 4 is one of a family of six FATPs that facilitate long- and very long-chain fatty acid uptake. Mice lacking FATP4 are born with tight, thick skin and a defective barrier; they die neonatally due to dehydration and restricted movements. Mutations in SLC27A4, the gene encoding FATP4, cause ichthyosis prematurity syndrome (IPS), characterized by premature birth, respiratory distress, and edematous skin with severe ichthyotic scaling. Symptoms of surviving patients become mild, though atopic manifestations are common. We previously showed that suprabasal keratinocyte expression of a Fatp4 transgene in Fatp4 mutant skin rescues the lethality and ameliorates the skin phenotype. Here we tested the hypothesis that FATP1, the closest FATP4 homolog, can compensate for the lack of FATP4 in our mouse model of IPS, as it might do postnatally in IPS patients. Transgenic expression of FATP1 in suprabasal keratinocytes rescued the phenotype of Fatp4 mutants, and FATP1 sorted to the same intracellular organelles as endogenous FATP4. Thus, FATP1 and FATP4 likely have overlapping substrate specificities, enzymatic activities, and biological functions. These results suggest that increasing expression of FATP1 in suprabasal keratinocytes could normalize the skin of IPS patients and perhaps prevent the atopic manifestations.
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Affiliation(s)
- Meei-Hua Lin
- Renal Division, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jeffrey H Miner
- Renal Division, Washington University School of Medicine, St. Louis, Missouri, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA.
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72
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Genistein induces deleterious effects during its acute exposure in Swiss mice. BIOMED RESEARCH INTERNATIONAL 2014; 2014:619617. [PMID: 24967385 PMCID: PMC4055018 DOI: 10.1155/2014/619617] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/14/2014] [Accepted: 04/15/2014] [Indexed: 12/27/2022]
Abstract
Genistein is a soy derived isoflavone. It has wide variety of therapeutic effects against certain diseases including cancer. Although toxic effects of genistein have been studied, its effect on the gene expression and the reason behind toxicity have not been identified yet. In the present study, genistein was administered to age and body weight matched Swiss mice at the doses of 125, 250, 500 and 1000 mg/kg. The biomarkers of hepatotoxicity in serum, liver histology, oxidative stress parameters in tissue homogenates, and global gene expression were examined. Elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) levels and degenerated liver tissue were observed in 500, and 1000 mg/kg genistein treated groups. Oxidative stress was significant at these doses as considerable increase in lipid peroxidation (LPO) and decrease in total glutathione (GSH) were observed. Gene expression analysis showed 40 differentially expressed genes at twofold change and P < 0.05.
Differentially expressed genes were corresponding to different biologically relevant pathways including metabolic and oxidative stress pathways. In 500 mg/kg group, Cyp4a14, Sult1e1, Gadd45g, Cidec, Mycs, and so forth genes were upregulated. These results suggested that the higher dose of genistein can produce several undesirable effects by affecting multiple cellular pathways.
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73
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Stremmel W, Staffer S, Wannhoff A, Pathil A, Chamulitrat W. Plasma membrane phospholipase A2 controls hepatocellular fatty acid uptake and is responsive to pharmacological modulation: implications for nonalcoholic steatohepatitis. FASEB J 2014; 28:3159-70. [PMID: 24719358 DOI: 10.1096/fj.14-249763] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Excess hepatic fat accumulation leads to nonalcoholic steatohepatitis (NASH), a serious threat to health for which no effective treatment is available. However, the mechanism responsible for fatty acid uptake by hepatocytes remains unclear. Using the human hepatocyte-derived tumor cell line HepG2, we found that fatty acid influx is mediated by a heterotetrameric plasma membrane protein complex consisting of plasma membrane fatty acid-binding protein, caveolin-1, CD36, and calcium-independent membrane phospholipase A2 (iPLA2β). Blocking iPLA2β with the bile acid-phospholipid conjugate ursodeoxycholate-lysophosphatidylethanolamide (UDCA-LPE) caused the dissociation of the complex, thereby inhibiting fatty acid influx (IC50 47 μM), and suppressed the synthesis of all subunits through a reduction in lysophosphatidylcholine from 8.0 to 3.5 μmol/mg of protein and corresponding depletion of phosphorylated c-Jun N-terminal kinase. These findings were substantiated by an observed 56.5% decrease in fatty acid influx in isolated hepatocytes derived from iPLA2β-knockout mice. Moreover, steatosis and inflammation were abrogated by UDCA-LPE treatment in a cellular model of NASH. Thus, iPLA2β acts as an upstream checkpoint for mechanisms that regulate fatty acid uptake, and its inhibition by UDCA-LPE qualifies this nontoxic compound as a therapeutic candidate for the treatment of NASH.-Stremmel, W., Staffer, S., Wannhoff, A., Pathil, A., Chamulitrat, W. Plasma membrane phospholipase A2 controls hepatocellular fatty acid uptake and is responsive to pharmacological modulation: implications for nonalcoholic steatohepatitis.
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Affiliation(s)
- Wolfgang Stremmel
- Department of Gastroenterology, University Hospital Heidelberg, Heidelberg, Germany
| | - Simone Staffer
- Department of Gastroenterology, University Hospital Heidelberg, Heidelberg, Germany
| | - Andreas Wannhoff
- Department of Gastroenterology, University Hospital Heidelberg, Heidelberg, Germany
| | - Anita Pathil
- Department of Gastroenterology, University Hospital Heidelberg, Heidelberg, Germany
| | - Walee Chamulitrat
- Department of Gastroenterology, University Hospital Heidelberg, Heidelberg, Germany
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74
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Protein mediated fatty acid uptake: Synergy between CD36/FAT-facilitated transport and acyl-CoA synthetase-driven metabolism. Arch Biochem Biophys 2014; 546:8-18. [DOI: 10.1016/j.abb.2014.01.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/17/2014] [Accepted: 01/23/2014] [Indexed: 11/21/2022]
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75
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Khan S, Abu Jawdeh BG, Goel M, Schilling WP, Parker MD, Puchowicz MA, Yadav SP, Harris RC, El-Meanawy A, Hoshi M, Shinlapawittayatorn K, Deschênes I, Ficker E, Schelling JR. Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis. J Clin Invest 2014; 124:1057-68. [PMID: 24531551 DOI: 10.1172/jci71863] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/11/2013] [Indexed: 12/12/2022] Open
Abstract
Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2-dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity.
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76
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Dongiovanni P, Anstee QM, Valenti L. Genetic predisposition in NAFLD and NASH: impact on severity of liver disease and response to treatment. Curr Pharm Des 2014; 19:5219-38. [PMID: 23394097 PMCID: PMC3850262 DOI: 10.2174/13816128113199990381] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 02/01/2013] [Indexed: 02/07/2023]
Abstract
Liver fat deposition related to systemic insulin resistance defines non-alcoholic fatty liver disease (NAFLD) which, when associated with oxidative hepatocellular damage, inflammation, and activation of fibrogenesis, i.e. non-alcoholic steatohepatitis (NASH), can progress towards cirrhosis and hepatocellular carcinoma. Due to the epidemic of obesity, NAFLD is now the most frequent liver disease and the leading cause of altered liver enzymes in Western countries. Epidemiological, familial, and twin studies provide evidence for an element of heritability of NAFLD. Genetic modifiers of disease severity and progression have been identified through genome-wide association studies. These include the Patatin-like phosholipase domain-containing 3 (PNPLA3) gene variant I148M as a major determinant of inter-individual and ethnicity-related differences in hepatic fat content independent of insulin resistance and serum lipid concentration. Association studies confirm that the I148M polymorphism is also a strong modifier of NASH and progressive hepatic injury. Furthermore, a few large multicentre case-control studies have demonstrated a role for genetic variants implicated in insulin signalling, oxidative stress, and fibrogenesis in the progression of NAFLD towards fibrosing NASH, and confirm that hepatocellular fat accumulation and insulin resistance are key operative mechanisms closely involved in the progression of liver damage. It is now important to explore the molecular mechanisms underlying these associations between gene variants and progressive liver disease, and to evaluate their impact on the response to available therapies. It is hoped that this knowledge will offer further insights into pathogenesis, suggest novel therapeutic targets, and could help guide physicians towards individualised therapy that improves clinical outcome.
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Affiliation(s)
- Paola Dongiovanni
- Department of Pathophysiology and Transplantation, section Internal Medicine, Università degli Studi Milano, UO Medicina Interna1B, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
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77
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Mehrotra D, Wu J, Papangeli I, Chun HJ. Endothelium as a gatekeeper of fatty acid transport. Trends Endocrinol Metab 2014; 25:99-106. [PMID: 24315207 PMCID: PMC3946743 DOI: 10.1016/j.tem.2013.11.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/04/2013] [Accepted: 11/05/2013] [Indexed: 12/13/2022]
Abstract
The endothelium transcends all clinical disciplines and is crucial to the function of every organ system. A critical, but poorly understood, role of the endothelium is its ability to control the transport of energy supply according to organ needs. Fatty acids (FAs) in particular represent a key energy source that is utilized by a number of tissues, but utilization must be tightly regulated to avoid potentially deleterious consequences of excess accumulation, including insulin resistance. Recent studies have identified important endothelial signaling mechanisms, involving vascular endothelial growth factor-B, peroxisome proliferator-activated receptor-γ, and apelin, that mediate endothelial regulation of FA transport. In this review, we discuss the mechanisms by which these signaling pathways regulate this key endothelial function.
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Affiliation(s)
- Devi Mehrotra
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Jingxia Wu
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Irinna Papangeli
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Hyung J Chun
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06511, USA.
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78
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Hagberg C, Mehlem A, Falkevall A, Muhl L, Eriksson U. Endothelial fatty acid transport: role of vascular endothelial growth factor B. Physiology (Bethesda) 2014; 28:125-34. [PMID: 23455771 DOI: 10.1152/physiol.00042.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dietary lipids present in the circulation have to be transported through the vascular endothelium to be utilized by tissue cells, a vital mechanism that is still poorly understood. Vascular endothelial growth factor B (VEGF-B) regulates this process by controlling the expression of endothelial fatty acid transporter proteins (FATPs). Here, we summarize research on the role of the vascular endothelium in nutrient transport, with emphasis on VEGF-B signaling.
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Yue X, Hariri DJ, Caballero B, Zhang S, Bartlett MJ, Kaut O, Mount DW, Wüllner U, Sherman SJ, Falk T. Comparative study of the neurotrophic effects elicited by VEGF-B and GDNF in preclinical in vivo models of Parkinson's disease. Neuroscience 2013; 258:385-400. [PMID: 24291725 DOI: 10.1016/j.neuroscience.2013.11.038] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 11/20/2013] [Accepted: 11/20/2013] [Indexed: 12/15/2022]
Abstract
Vascular endothelial growth factor B (VEGF-B) has recently been shown to be a promising novel neuroprotective agent for several neurodegenerative conditions. In the current study we extended previous work on neuroprotective potential for Parkinson's disease (PD) by testing an expanded dose range of VEGF-B (1 and 10 μg) and directly comparing both neuroprotective and neurorestorative effects of VEGF-B in progressive unilateral 6-hydroxydopamine (6-OHDA) PD models to a single dose of glial cell line-derived neurotrophic factor (GDNF, 10 μg), that has been established by several groups as a standard in both preclinical PD models. In the amphetamine-induced rotational tests the treatment with 1 and 10 μg VEGF-B resulted in significantly improved motor function of 6-OHDA-lesioned rats compared to vehicle-treated 6-OHDA-lesioned rats in the neuroprotection paradigm. Both doses of VEGF-B caused an increase in tyrosine hydroxylase (TH)-positive cell and fiber count in the substantia nigra (SN) and striatum in the neuroprotective experiment. The effect size was comparable to the effects seen with GDNF. In the neurorestoration paradigm, VEGF-B injection had no significant effect in either the behavioral or the immunohistochemical analyses, whereas GDNF injection significantly improved the amphetamine-induced rotational behavior and reduced TH-positive neuronal cell loss in the SN. We also present a strong positive correlation (p=1.9e-50) of the expression of VEGF-B with nuclear-encoded mitochondrial genes involved in fatty acid metabolism in rat midbrain, pointing to the mitochondria as a site of action of VEGF-B. GDNF showed a positive correlation with nuclear-encoded mitochondrial genes that was not nearly as strong (p=0.018). VEGF-B counteracted rotenone-induced reduction of (a) fatty acid transport protein 1 and 4 levels and (b) both Akt protein and phosphorylation levels in SH-SY5Y cells. We further verified VEGF-B expression in the human SN pars compacta of healthy controls and PD patients, in neuronal cells that show co-expression with neuromelanin. These results have demonstrated that VEGF-B has potential as a neuroprotective agent for PD therapy and should be further investigated.
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Affiliation(s)
- X Yue
- Department of Neurology, University of Arizona, Tucson, AZ 85724, USA
| | - D J Hariri
- Graduate Interdisciplinary Program in Physiological Sciences, University of Arizona, Tucson, AZ 85724, USA
| | - B Caballero
- Graduate Interdisciplinary Program in Physiological Sciences, University of Arizona, Tucson, AZ 85724, USA
| | - S Zhang
- Department of Neurology, University of Arizona, Tucson, AZ 85724, USA
| | - M J Bartlett
- Department of Neurology, University of Arizona, Tucson, AZ 85724, USA
| | - O Kaut
- Department of Neurology, University of Bonn, 53105 Bonn, Germany
| | - D W Mount
- Bioinformatics Shared Service, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA
| | - U Wüllner
- Department of Neurology, University of Bonn, 53105 Bonn, Germany
| | - S J Sherman
- Department of Neurology, University of Arizona, Tucson, AZ 85724, USA
| | - T Falk
- Department of Neurology, University of Arizona, Tucson, AZ 85724, USA; Graduate Interdisciplinary Program in Physiological Sciences, University of Arizona, Tucson, AZ 85724, USA.
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80
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Actinobacterial acyl coenzyme A synthetases involved in steroid side-chain catabolism. J Bacteriol 2013; 196:579-87. [PMID: 24244004 DOI: 10.1128/jb.01012-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bacterial steroid catabolism is an important component of the global carbon cycle and has applications in drug synthesis. Pathways for this catabolism involve multiple acyl coenzyme A (CoA) synthetases, which activate alkanoate substituents for β-oxidation. The functions of these synthetases are poorly understood. We enzymatically characterized four distinct acyl-CoA synthetases from the cholate catabolic pathway of Rhodococcus jostii RHA1 and the cholesterol catabolic pathway of Mycobacterium tuberculosis. Phylogenetic analysis of 70 acyl-CoA synthetases predicted to be involved in steroid metabolism revealed that the characterized synthetases each represent an orthologous class with a distinct function in steroid side-chain degradation. The synthetases were specific for the length of alkanoate substituent. FadD19 from M. tuberculosis H37Rv (FadD19Mtb) transformed 3-oxo-4-cholesten-26-oate (kcat/Km = 0.33 × 10(5) ± 0.03 × 10(5) M(-1) s(-1)) and represents orthologs that activate the C8 side chain of cholesterol. Both CasGRHA1 and FadD17Mtb are steroid-24-oyl-CoA synthetases. CasG and its orthologs activate the C5 side chain of cholate, while FadD17 and its orthologs appear to activate the C5 side chain of one or more cholesterol metabolites. CasIRHA1 is a steroid-22-oyl-CoA synthetase, representing orthologs that activate metabolites with a C3 side chain, which accumulate during cholate catabolism. CasI had similar apparent specificities for substrates with intact or extensively degraded steroid nuclei, exemplified by 3-oxo-23,24-bisnorchol-4-en-22-oate and 1β(2'-propanoate)-3aα-H-4α(3″-propanoate)-7aβ-methylhexahydro-5-indanone (kcat/Km = 2.4 × 10(5) ± 0.1 × 10(5) M(-1) s(-1) and 3.2 × 10(5) ± 0.3 × 10(5) M(-1) s(-1), respectively). Acyl-CoA synthetase classes involved in cholate catabolism were found in both Actinobacteria and Proteobacteria. Overall, this study provides insight into the physiological roles of acyl-CoA synthetases in steroid catabolism and a phylogenetic classification enabling prediction of specific functions of related enzymes.
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Xu J, Donepudi AC, Moscovitz JE, Slitt AL. Keap1-knockdown decreases fasting-induced fatty liver via altered lipid metabolism and decreased fatty acid mobilization from adipose tissue. PLoS One 2013; 8:e79841. [PMID: 24224011 PMCID: PMC3817107 DOI: 10.1371/journal.pone.0079841] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/25/2013] [Indexed: 01/10/2023] Open
Abstract
AIMS The purpose of this study was to determine whether Nrf2 activation, via Keap1-knockdown (Keap1-KD), regulates lipid metabolism and mobilization induced by food deprivation (e.g. fasting). METHODS AND RESULTS Male C57BL/6 (WT) and Keap1-KD mice were either fed ad libitum or food deprived for 24 hours. After fasting, WT mice exhibited a marked increase in hepatic lipid accumulation, but Keap1-KD mice had an attenuated increase of lipid accumulation, along with reduced expression of lipogenic genes (acetyl-coA carboxylase, stearoyl-CoA desaturase-1, and fatty acid synthase) and reduced expression of genes related to fatty acid transport, such as fatty acid translocase/CD36 (CD36) and Fatty acid transport protein (FATP) 2, which may attribute to the reduced induction of Peroxisome proliferator-activated receptor (Ppar) α signaling in the liver. Additionally, enhanced Nrf2 activity by Keap1-KD increased AMP-activated protein kinase (AMPK) phosphorylation in liver. In white adipose tissue, enhanced Nrf2 activity did not change the lipolysis rate by fasting, but reduced expression of fatty acid transporters--CD36 and FATP1, via a PPARα-dependent mechanism, which impaired fatty acid transport from white adipose tissue to periphery circulation system, and resulted in increased white adipose tissue fatty acid content. Moreover, enhanced Nrf2 activity increased glucose tolerance and Akt phosphorylation levels upon insulin administration, suggesting Nrf2 signaling pathway plays a key role in regulating insulin signaling and enhanced insulin sensitivity in skeletal muscle. CONCLUSION Enhanced Nrf2 activity via Keap1-KD decreased fasting-induced steatosis, pointing to an important function of Nrf2 on lipid metabolism under the condition of nutrient deprivation.
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Affiliation(s)
- Jialin Xu
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
- Institute of Biochemistry and Molecular Biology, College of Life and Health Sciences, Northeastern University, Shenyang, P. R. China
| | - Ajay C. Donepudi
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Jamie E. Moscovitz
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Angela L. Slitt
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, United States of America
- * E-mail:
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82
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Anderson CM, Stahl A. SLC27 fatty acid transport proteins. Mol Aspects Med 2013; 34:516-28. [PMID: 23506886 DOI: 10.1016/j.mam.2012.07.010] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/18/2012] [Indexed: 12/20/2022]
Abstract
The uptake and metabolism of long chain fatty acids (LCFA) are critical to many physiological and cellular processes. Aberrant accumulation or depletion of LCFA underlie the pathology of numerous metabolic diseases. Protein-mediated transport of LCFA has been proposed as the major mode of LCFA uptake and activation. Several proteins have been identified to be involved in LCFA uptake. This review focuses on the SLC27 family of fatty acid transport proteins, also known as FATPs, with an emphasis on the gain- and loss-of-function animal models that elucidate the functions of FATPs in vivo and how these transport proteins play a role in physiological and pathological situations.
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Affiliation(s)
- Courtney M Anderson
- Metabolic Biology, Department of Nutritional Sciences and Toxicology, University of California Berkeley, CA, USA
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83
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Kawano Y, Cohen DE. Mechanisms of hepatic triglyceride accumulation in non-alcoholic fatty liver disease. J Gastroenterol 2013; 48:434-41. [PMID: 23397118 PMCID: PMC3633701 DOI: 10.1007/s00535-013-0758-5] [Citation(s) in RCA: 619] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/15/2013] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic lipid accumulation in the absence of excess alcohol intake. NAFLD is the most common chronic liver disease, and ongoing research efforts are focused on understanding the underlying pathobiology of hepatic steatosis with the anticipation that these efforts will identify novel therapeutic targets. Under physiological conditions, the low steady-state triglyceride concentrations in the liver are attributable to a precise balance between acquisition by uptake of non-esterified fatty acids from the plasma and by de novo lipogenesis, versus triglyceride disposal by fatty acid oxidation and by the secretion of triglyceride-rich lipoproteins. In NAFLD patients, insulin resistance leads to hepatic steatosis by multiple mechanisms. Greater uptake rates of plasma non-esterified fatty acids are attributable to increased release from an expanded mass of adipose tissue as a consequence of diminished insulin responsiveness. Hyperinsulinemia promotes the transcriptional upregulation of genes that promote de novo lipogenesis in the liver. Increased hepatic lipid accumulation is not offset by fatty acid oxidation or by increased secretion rates of triglyceride-rich lipoproteins. This review discusses the molecular mechanisms by which hepatic triglyceride homeostasis is achieved under normal conditions, as well as the metabolic alterations that occur in the setting of insulin resistance and contribute to the pathogenesis of NAFLD.
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Affiliation(s)
- Yuki Kawano
- Division of Gastroenterology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115 USA
| | - David E. Cohen
- Division of Gastroenterology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115 USA
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84
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O'Neill HM, Holloway GP, Steinberg GR. AMPK regulation of fatty acid metabolism and mitochondrial biogenesis: implications for obesity. Mol Cell Endocrinol 2013; 366:135-51. [PMID: 22750049 DOI: 10.1016/j.mce.2012.06.019] [Citation(s) in RCA: 241] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/13/2012] [Accepted: 06/21/2012] [Indexed: 12/25/2022]
Abstract
Skeletal muscle plays an important role in regulating whole-body energy expenditure given it is a major site for glucose and lipid oxidation. Obesity and type 2 diabetes are causally linked through their association with skeletal muscle insulin resistance, while conversely exercise is known to improve whole body glucose homeostasis simultaneously with muscle insulin sensitivity. Exercise activates skeletal muscle AMP-activated protein kinase (AMPK). AMPK plays a role in regulating exercise capacity, skeletal muscle mitochondrial content and contraction-stimulated glucose uptake. Skeletal muscle AMPK is also thought to be important for regulating fatty acid metabolism; however, direct genetic evidence in this area is currently lacking. This review will discuss the current paradigms regarding the influence of AMPK in regulating skeletal muscle fatty acid metabolism and mitochondrial biogenesis at rest and during exercise, and highlight the potential implications in the development of insulin resistance.
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Affiliation(s)
- Hayley M O'Neill
- University of Melbourne, Department of Medicine, St. Vincent's Institute of Medical Research, Melbourne, Victoria, Australia.
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85
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Sujkowski A, Saunders S, Tinkerhess M, Piazza N, Jennens J, Healy L, Zheng L, Wessells R. dFatp regulates nutrient distribution and long-term physiology in Drosophila. Aging Cell 2012; 11:921-32. [PMID: 22809097 PMCID: PMC3533766 DOI: 10.1111/j.1474-9726.2012.00864.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2012] [Indexed: 12/31/2022] Open
Abstract
Nutrient allocation and usage plays an important part in regulating the onset and progression of age-related functional declines. Here, we describe a heterozygous mutation in Drosophila (dFatp) that alters nutrient distribution and multiple aspects of physiology. dFatp mutants have increased lifespan and stress resistance, altered feeding behavior and fat storage, and increased mobility. Concurrently, mutants experience impairment of cardiac function. We show that endurance exercise reverses increased lipid storage in the myocardium and the deleterious cardiac function conferred by dFatp mutation. These findings establish a novel conserved genetic target for regulating lifespan and physiology in aging animals. These findings also highlight the importance of varying exercise conditions in assessing aging functions of model organisms.
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Affiliation(s)
- Alyson Sujkowski
- Department of Internal Medicine, Institute of Gerontology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Qi R, Feng M, Tan X, Gan L, Yan G, Sun C. FATP1 silence inhibits the differentiation and induces the apoptosis in chicken preadipocytes. Mol Biol Rep 2012. [PMID: 23187737 DOI: 10.1007/s11033-012-2306-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
FATP1 plays an important role in the trafficking of free fatty acids in adipocytes, however, its precise function and relationship with other fatty acid transporters all remain poorly understood. In this study, FATP1 gene silencing was induced by transfecting siRNA of target sequence into chicken preadipocytes, then the expression of FABP was found down-regulated while the expression of FAT was raised. In addition, differential inhibition of the cells was observed and the expressions of PPARγ and C/EBPα were found down-regulated. Moreover, the silencing also induced the down-regulation of FAS and inhibited the adipogenesis in adipocytes. Of specific interest here was that FATP1 silencing significantly improved the expressions and activities of cell apoptotic factors Caspases 3 and BCL2 associated X protein (Bax). Consequently, FATP1 deficiency prevented the differentiation while induced apoptosis in chicken preadipocytes.
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Affiliation(s)
- Renli Qi
- College of Animal Science & Technology, Northwest A&F University, Yangling 712100, China
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87
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Chekroud K, Guillou L, Grégoire S, Ducharme G, Brun E, Cazevieille C, Bretillon L, Hamel CP, Brabet P, Pequignot MO. Fatp1 deficiency affects retinal light response and dark adaptation, and induces age-related alterations. PLoS One 2012; 7:e50231. [PMID: 23166839 PMCID: PMC3500375 DOI: 10.1371/journal.pone.0050231] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 10/19/2012] [Indexed: 11/19/2022] Open
Abstract
FATP1 is involved in lipid transport into cells and in intracellular lipid metabolism. We showed previously that this protein interacts with and inhibits the limiting-step isomerase of the visual cycle RPE65. Here, we aimed to analyze the effect of Fatp1-deficiency in vivo on the visual cycle, structure and function, and on retinal aging. Among the Fatp family members, we observed that only Fatp1 and 4 are expressed in the control retina, in both the neuroretina and the retinal pigment epithelium. In the neuroretina, Fatp1 is mostly expressed in photoreceptors. In young adult Fatp1−/− mice, Fatp4 expression was unchanged in retinal pigment epithelium and reduced two-fold in the neuroretina as compared to Fatp1+/+ mice. The Fatp1−/− mice had a preserved retinal structure but a decreased electroretinogram response to light. These mice also displayed a delayed recovery of the b-wave amplitude after bleaching, however, visual cycle speed was unchanged, and both retinal pigment epithelium and photoreceptors presented the same fatty acid pattern compared to controls. In 2 year-old Fatp1−/− mice, transmission electron microscopy studies showed specific abnormalities in the retinas comprising choroid vascularization anomalies and thickening of the Bruch membrane with material deposits, and sometimes local disorganization of the photoreceptor outer segments. These anomalies lead us to speculate that the absence of FATP1 accelerates the aging process.
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Affiliation(s)
- Karim Chekroud
- Inserm U1051, Institute for Neurosciences of Montpellier, CHU St Eloi, Montpellier, France
| | - Laurent Guillou
- Inserm U1051, Institute for Neurosciences of Montpellier, CHU St Eloi, Montpellier, France
| | | | - Gilles Ducharme
- CNRS UMR5149, Institut de Mathématiques et de Modélisation de Montpellier, France
| | - Emilie Brun
- Inserm U1051, Institute for Neurosciences of Montpellier, CHU St Eloi, Montpellier, France
| | | | | | - Christian P. Hamel
- Inserm U1051, Institute for Neurosciences of Montpellier, CHU St Eloi, Montpellier, France
| | - Philippe Brabet
- Inserm U1051, Institute for Neurosciences of Montpellier, CHU St Eloi, Montpellier, France
- * E-mail: (MOP); (PB)
| | - Marie O. Pequignot
- Inserm U1051, Institute for Neurosciences of Montpellier, CHU St Eloi, Montpellier, France
- * E-mail: (MOP); (PB)
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Ngo VA, Kalia RK, Nakano A, Vashishta P. Molecular Mechanism of Flip-Flop in Triple-Layer Oleic-Acid Membrane: Correlation between Oleic Acid and Water. J Phys Chem B 2012; 116:13416-23. [DOI: 10.1021/jp307227r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Van A. Ngo
- Department of Physics
and Astronomy, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Rajiv K. Kalia
- Collaboratory for Advanced Computing
and Simulations, Department of Physics and Astronomy, Department of
Chemical Engineering and Materials Science, and Department of Computer
Science, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing
and Simulations, Department of Physics and Astronomy, Department of
Chemical Engineering and Materials Science, and Department of Computer
Science, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Priya Vashishta
- Collaboratory for Advanced Computing
and Simulations, Department of Physics and Astronomy, Department of
Chemical Engineering and Materials Science, and Department of Computer
Science, University of Southern California, Los Angeles, California 90089-0242, United States
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89
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Saraya MA, Al-Fadhli MA, Qasem JA. Diabetic status of patients with leprosy in Kuwait. J Infect Public Health 2012; 5:360-5. [PMID: 23164565 DOI: 10.1016/j.jiph.2012.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 07/29/2012] [Accepted: 08/09/2012] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE The aim of this study was to screen for diabetes mellitus in leprosy patients to elucidate whether leprosy infection may play a role in the pathogenesis of diabetes mellitus in this population. SUBJECTS AND METHODS Thirty patients of different ages and of both sexes with various types of leprosy were included in this study. In addition, 15 healthy individuals of comparable age and sex who had no family history of diabetes mellitus were identified as controls. In both groups, determinations of fasting and postprandial blood sugar, an oral glucose tolerance test (OGTT), measures of fasting serum insulin and pro-inflammatory cytokine tumor necrosis factor alpha (TNFα), as well as calculations using the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), were carried out. RESULT Approximately 13.3% of the leprosy patients were diabetic, and 37.7% were in pre-diabetic. The highest incidences of diabetes and pre-diabetes were in lepromatous leprosy (10% and 20%, respectively); a lower incidence of pre-diabetes (6.6%) was observed in tuberculoid leprosy; and the lowest incidence of diabetes (0.0%) was noted in borderline leprosy patients. Although normal healthy persons were not diabetic (0%), 20% were pre-diabetic. CONCLUSION This study revealed that the incidence of diabetes was higher in the leprosy patients than in the control group. As a result, we recommend that all leprosy patients should be screened for diabetes.
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Affiliation(s)
- Mohammad A Saraya
- Department of Medicine, Infectious Disease Hospital, Ministry of Health, Kuwait
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90
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Nie B, Park HM, Kazantzis M, Lin M, Henkin A, Ng S, Song S, Chen Y, Tran H, Lai R, Her C, Maher JJ, Forman BM, Stahl A. Specific bile acids inhibit hepatic fatty acid uptake in mice. Hepatology 2012; 56:1300-10. [PMID: 22531947 PMCID: PMC3445775 DOI: 10.1002/hep.25797] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
UNLABELLED Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. We tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end, stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. CONCLUSION The data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease.
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Affiliation(s)
- Biao Nie
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Hyo Min Park
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Melissa Kazantzis
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Min Lin
- Diabetes Center, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Amy Henkin
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Stephanie Ng
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Sujin Song
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Yuli Chen
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Heather Tran
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Robin Lai
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
| | - Chris Her
- Department of Medicine and Liver Center, University of California San Francisco, 1001 Potrero Ave., San Francisco, CA 94110
| | - Jacquelyn J. Maher
- Department of Medicine and Liver Center, University of California San Francisco, 1001 Potrero Ave., San Francisco, CA 94110
| | - Barry M. Forman
- Diabetes Center, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Andreas Stahl
- Department of Nutritional Science and Toxicology, University of California Berkeley, Berkeley, CA 94720
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Softic S, Kirby M, Berger NG, Shroyer NF, Woods SC, Kohli R. Insulin concentration modulates hepatic lipid accumulation in mice in part via transcriptional regulation of fatty acid transport proteins. PLoS One 2012; 7:e38952. [PMID: 22745692 PMCID: PMC3380053 DOI: 10.1371/journal.pone.0038952] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 05/16/2012] [Indexed: 12/18/2022] Open
Abstract
Background Fatty liver disease (FLD) is commonly associated with insulin resistance and obesity, but interestingly it is also observed at low insulin states, such as prolonged fasting. Thus, we asked whether insulin is an independent modulator of hepatic lipid accumulation. Methods/Principal Findings In mice we induced, hypo- and hyperinsulinemia associated FLD by diet induced obesity and streptozotocin treatment, respectively. The mechanism of free fatty acid induced steatosis was studied in cell culture with mouse liver cells under different insulin concentrations, pharmacological phosphoinositol-3-kinase (PI3K) inhibition and siRNA targeted gene knock-down. We found with in vivo and in vitro models that lipid storage is increased, as expected, in both hypo- and hyperinsulinemic states, and that it is mediated by signaling through either insulin receptor substrate (IRS) 1 or 2. As previously reported, IRS-1 was up-regulated at high insulin concentrations, while IRS-2 was increased at low levels of insulin concentration. Relative increase in either of these insulin substrates, was associated with an increase in liver-specific fatty acid transport proteins (FATP) 2&5, and increased lipid storage. Furthermore, utilizing pharmacological PI3K inhibition we found that the IRS-PI3K pathway was necessary for lipogenesis, while FATP responses were mediated via IRS signaling. Data from additional siRNA experiments showed that knock-down of IRSs impacted FATP levels. Conclusions/Significance States of perturbed insulin signaling (low-insulin or high-insulin) both lead to increased hepatic lipid storage via FATP and IRS signaling. These novel findings offer a common mechanism of FLD pathogenesis in states of both inadequate (prolonged fasting) and ineffective (obesity) insulin signaling.
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Affiliation(s)
- Samir Softic
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, Riley Hospital for Children, Indiana University, Indianapolis, Indiana, United States of America
| | - Michelle Kirby
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Nicholas G. Berger
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Noah F. Shroyer
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Stephen C. Woods
- Metabolic Diseases Institute, Obesity Research Center, Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Rohit Kohli
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- * E-mail:
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92
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The Mycobacterium tuberculosis Very-Long-Chain Fatty Acyl-CoA Synthetase: Structural Basis for Housing Lipid Substrates Longer than the Enzyme. Structure 2012; 20:1062-70. [DOI: 10.1016/j.str.2012.03.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 03/23/2012] [Accepted: 03/23/2012] [Indexed: 11/17/2022]
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93
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Castillo C, Chen H, Graves C, Maisonnasse A, Le Conte Y, Plettner E. Biosynthesis of ethyl oleate, a primer pheromone, in the honey bee (Apis mellifera L.). INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:404-416. [PMID: 22406167 DOI: 10.1016/j.ibmb.2012.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/18/2012] [Accepted: 02/21/2012] [Indexed: 05/31/2023]
Abstract
Honey bees undergo a physiological transition from nursing to foraging approximately 21 days after adult emergence. This transition is delayed by ethyl oleate (EO), a primer pheromone produced by foragers when exposed to ethanol from fermented nectar. We demonstrate here that two secreted α/β-hydrolases (BeeBase ID: GB11403 and GB13365) are responsible for the reversible esterification of ethanol with oleic acid, giving EO. Expression of hydrolase GB11403 was shown to be significantly up-regulated in foragers, relative to nurses. Tissue perfusion experiments with labeled substrates consistently localized the highest level of EO production in the head, whereas in situ imaging revealed expression of relevant EO biosynthetic genes and enzymatic activity along the esophagus, the site of ethanol exposure during nectar intake. Both α/β-hydrolases were expressed in Pichia pastoris, purified and were shown produce EO in vitro. Experiments with live bees fed ethanol demonstrated that EO formed in regurgitate accumulates in the honey crop and exudes to the exoskeleton, from where it exerts its primer effect on younger bees.
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Affiliation(s)
- Carlos Castillo
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6 Canada.
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94
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Caccia S, Grimaldi A, Casartelli M, Falabella P, de Eguileor M, Pennacchio F, Giordana B. Functional analysis of a fatty acid binding protein produced by Aphidius ervi teratocytes. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:621-627. [PMID: 22226822 DOI: 10.1016/j.jinsphys.2011.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 05/31/2023]
Abstract
Aphidius ervi (Hymenoptera, Braconidae) is an endophagous parasitoid of various aphid species, including Acyrthosiphon pisum (Homoptera, Aphididae), the model host used in the present study. Parasitized hosts show a marked increase of their nutritional suitability for the developing parasitoid larvae. This alteration of the biochemical and metabolic profile is due to a castration process mediated by the combined action of the venom, injected at the oviposition, and of the teratocytes, cells deriving from the dissociation of the embryonic membrane. Teratocytes produce and release in the host haemocoel two parasitism-specific proteins, which are of crucial importance for the development of their sister larvae. One of the proteins is a fatty acid binding protein (Ae-FABP), which shows a high affinity for C14-C18 saturated fatty acids (FAs) and for oleic and arachidonic acids. To better define the possible nutritional role of this protein, we have studied its immunolocalization profile in vivo and the impact on FA uptake by the epidermal and midgut epithelia of A. ervi larvae. During the exponential growth of A. ervi larvae, Ae-FABP is distributed around discrete lipid particles, which are abundantly present in the haemocoel of parasitized host aphids and in the midgut lumen of parasitoid larvae. Moreover, a strong immunodetection signal is evident on the surface of the two larval epithelia involved in nutrient absorption: the parasitoid midgut epithelium and the external epidermal layer. These two epithelia can effectively absorb radiolabelled myristic acid, but the FA transport rates are not affected by the presence in the medium of Ae-FABP. The protein appears to act essentially as a vector in the host haemolymph, transferring FAs from the digestion sites of host lipids to the growing parasitoid larvae. These data indicate that the proteins produced by A. ervi teratocytes may play complementary roles in the nutritional exploitation of the host.
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Affiliation(s)
- Silvia Caccia
- Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, Milano, Italy
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95
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Soronen J, Laurila PP, Naukkarinen J, Surakka I, Ripatti S, Jauhiainen M, Olkkonen VM, Yki-Järvinen H. Adipose tissue gene expression analysis reveals changes in inflammatory, mitochondrial respiratory and lipid metabolic pathways in obese insulin-resistant subjects. BMC Med Genomics 2012; 5:9. [PMID: 22471940 PMCID: PMC3384471 DOI: 10.1186/1755-8794-5-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 04/03/2012] [Indexed: 02/06/2023] Open
Abstract
Background To get insight into molecular mechanisms underlying insulin resistance, we compared acute in vivo effects of insulin on adipose tissue transcriptional profiles between obese insulin-resistant and lean insulin-sensitive women. Methods Subcutaneous adipose tissue biopsies were obtained before and after 3 and 6 hours of intravenously maintained euglycemic hyperinsulinemia from 9 insulin-resistant and 11 insulin-sensitive females. Gene expression was measured using Affymetrix HG U133 Plus 2 microarrays and qRT-PCR. Microarray data and pathway analyses were performed with Chipster v1.4.2 and by using in-house developed nonparametric pathway analysis software. Results The most prominent difference in gene expression of the insulin-resistant group during hyperinsulinemia was reduced transcription of nuclear genes involved in mitochondrial respiration (mitochondrial respiratory chain, GO:0001934). Inflammatory pathways with complement components (inflammatory response, GO:0006954) and cytokines (chemotaxis, GO:0042330) were strongly up-regulated in insulin-resistant as compared to insulin-sensitive subjects both before and during hyperinsulinemia. Furthermore, differences were observed in genes contributing to fatty acid, cholesterol and triglyceride metabolism (FATP2, ELOVL6, PNPLA3, SREBF1) and in genes involved in regulating lipolysis (ANGPTL4) between the insulin-resistant and -sensitive subjects especially during hyperinsulinemia. Conclusions The major finding of this study was lower expression of mitochondrial respiratory pathway and defective induction of lipid metabolism pathways by insulin in insulin-resistant subjects. Moreover, the study reveals several novel genes whose aberrant regulation is associated with the obese insulin-resistant phenotype.
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Affiliation(s)
- Jarkko Soronen
- FIMM, Institute for Molecular Medicine Finland, University of Helsinki, Finland.
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96
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Enhanced fatty acid oxidation and FATP4 protein expression after endurance exercise training in human skeletal muscle. PLoS One 2012; 7:e29391. [PMID: 22235293 PMCID: PMC3250432 DOI: 10.1371/journal.pone.0029391] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 11/28/2011] [Indexed: 11/29/2022] Open
Abstract
FATP1 and FATP4 appear to be important for the cellular uptake and handling of long chain fatty acids (LCFA). These findings were obtained from loss- or gain of function models. However, reports on FATP1 and FATP4 in human skeletal muscle are limited. Aerobic training enhances lipid oxidation; however, it is not known whether this involves up-regulation of FATP1 and FATP4 protein. Therefore, the aim of this project was to investigate FATP1 and FATP4 protein expression in the vastus lateralis muscle from healthy human individuals and to what extent FATP1 and FATP4 protein expression were affected by an increased fuel demand induced by exercise training. Eight young healthy males were recruited to the study. All subjects were non smokers and did not participate in regular physical activity (<1 time per week for the past 6 months, VO2peak 3.4±0.1 l O2 min−1). Subjects underwent an 8 week supervised aerobic training program. Training induced an increase in VO2peak from 3.4±0.1 to 3.9±0.1 l min−1 and citrate synthase activity was increased from 53.7±2.5 to 80.8±3.7 µmol g−1 min−1. The protein content of FATP4 was increased by 33%, whereas FATP1 protein content was reduced by 20%. Interestingly, at the end of the training intervention a significant association (r2 = 0.74) between the observed increase in skeletal muscle FATP4 protein expression and lipid oxidation during a 120 min endurance exercise test was observed. In conclusion, based on the present findings it is suggested that FATP1 and FATP4 proteins perform different functional roles in handling LCFA in skeletal muscle with FATP4 apparently more important as a lipid transport protein directing lipids for lipid oxidation.
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97
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Abstract
The study of endocannabinoid pharmacology has proceeded from the discovery of Δ9-tetrahydrocannabinol, the main psychoactive compound in Cannabis sativa, to the identification of an endogenous endocannabinoid system that is essential for physiological modulation of neuronal functions. We have not yet achieved a complete understanding of the various roles of the endocannabinoids, but this is one of the fastest-growing fields in psychopharmacology. This review starts with a brief historical description of the discovery of the endocannabinoids and then focuses on recent pharmacological advances and recently discovered endocannabinoid mechanisms of action (e.g. functional selectivity, allosterism, and receptor trafficking). Finally, we will discuss the contention that the existence of evidence-based therapeutic applications for cannabinoids and the wide range of physiological functions affected by endocannabinoids suggests that the careful study of the endocannabinoid system may lead to the development of novel therapeutic drugs with higher societal acceptability and lower side effects profiles.
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Affiliation(s)
- F A Pamplona
- Laboratory of Psychopharmacology, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil.
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98
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Youm J, Saier MH. Comparative analyses of transport proteins encoded within the genomes of Mycobacterium tuberculosis and Mycobacterium leprae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:776-97. [PMID: 22179038 DOI: 10.1016/j.bbamem.2011.11.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 11/18/2011] [Accepted: 11/18/2011] [Indexed: 10/15/2022]
Abstract
The co-emergence of multidrug resistant pathogenic bacterial strains and the Human Immunodeficiency Virus pandemic has made tuberculosis a leading public health threat. The causative agent is Mycobacterium tuberculosis (Mtu), a facultative intracellular parasite. Mycobacterium leprae (Mle), a related organism that causes leprosy, is an obligate intracellular parasite. Given that different transporters are required for bacterial growth and persistence under a variety of growth conditions, we conducted comparative analyses of transport proteins encoded within the genomes of these two organisms. A minimal set of genes required for intracellular and extracellular life was identified. Drug efflux systems utilizing primary active transport mechanisms have been preferentially retained in Mle and still others preferentially lost. Transporters associated with environmental adaptation found in Mtu were mostly lost in Mle. These findings provide starting points for experimental studies that may elucidate the dependencies of pathogenesis on transport for these two pathogenic mycobacteria. They also lead to suggestions regarding transporters that function in intra- versus extra-cellular growth.
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Affiliation(s)
- Jiwon Youm
- University of California, La Jolla, CA, USA
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99
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Bazan NG, Molina MF, Gordon WC. Docosahexaenoic acid signalolipidomics in nutrition: significance in aging, neuroinflammation, macular degeneration, Alzheimer's, and other neurodegenerative diseases. Annu Rev Nutr 2011; 31:321-51. [PMID: 21756134 DOI: 10.1146/annurev.nutr.012809.104635] [Citation(s) in RCA: 298] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Essential polyunsaturated fatty acids (PUFAs) are critical nutritional lipids that must be obtained from the diet to sustain homeostasis. Omega-3 and -6 PUFAs are key components of biomembranes and play important roles in cell integrity, development, maintenance, and function. The essential omega-3 fatty acid family member docosahexaenoic acid (DHA) is avidly retained and uniquely concentrated in the nervous system, particularly in photoreceptors and synaptic membranes. DHA plays a key role in vision, neuroprotection, successful aging, memory, and other functions. In addition, DHA displays anti-inflammatory and inflammatory resolving properties in contrast to the proinflammatory actions of several members of the omega-6 PUFAs family. This review discusses DHA signalolipidomics, comprising the cellular/tissue organization of DHA uptake, its distribution among cellular compartments, the organization and function of membrane domains rich in DHA-containing phospholipids, and the cellular and molecular events revealed by the uncovering of signaling pathways regulated by DHA and docosanoids, the DHA-derived bioactive lipids, which include neuroprotectin D1 (NPD1), a novel DHA-derived stereoselective mediator. NPD1 synthesis agonists include neurotrophins and oxidative stress; NPD1 elicits potent anti-inflammatory actions and prohomeostatic bioactivity, is anti-angiogenic, promotes corneal nerve regeneration, and induces cell survival. In the context of DHA signalolipidomics, this review highlights aging and the evolving studies on the significance of DHA in Alzheimer's disease, macular degeneration, Parkinson's disease, and other brain disorders. DHA signalolipidomics in the nervous system offers emerging targets for pharmaceutical intervention and clinical translation.
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Affiliation(s)
- Nicolas G Bazan
- Neuroscience Center of Excellence and Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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100
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Digel M, Staffer S, Ehehalt F, Stremmel W, Ehehalt R, Füllekrug J. FATP4 contributes as an enzyme to the basal and insulin-mediated fatty acid uptake of C₂C₁₂ muscle cells. Am J Physiol Endocrinol Metab 2011; 301:E785-96. [PMID: 21750264 DOI: 10.1152/ajpendo.00079.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The function of membrane proteins in long-chain fatty acid transport is controversial. The acyl-CoA synthetase fatty acid transport protein-4 (FATP4) has been suggested to facilitate fatty acid uptake indirectly by its enzymatic activity, or directly by transport across the plasma membrane. Here, we investigated the function of FATP4 in basal and insulin mediated fatty acid uptake in C(2)C(12) muscle cells, a model system relevant for fatty acid metabolism. Stable expression of exogenous FATP4 resulted in a twofold higher fatty acyl-CoA synthetase activity, and cellular uptake of oleate was enhanced similarly. Kinetic analysis demonstrated that FATP4 allowed the cells to reach apparent saturation of fatty acid uptake at a twofold higher level compared with control. Short-term treatment with insulin increased fatty acid uptake in line with previous reports. Surprisingly, insulin increased the acyl-CoA synthetase activity of C(2)C(12) cells within minutes. This effect was sensitive to inhibition of insulin signaling by wortmannin. Affinity purified FATP4 prepared from insulin-treated cells showed an enhanced enzyme activity, suggesting it constitutes a novel target of short-term metabolic regulation by insulin. This offers a new mechanistic explanation for the concomitantly observed enhanced fatty acid uptake. FATP4 was colocalized to the endoplasmic reticulum by double immunofluorescence and subcellular fractionation, clearly distinct from the plasma membrane. Importantly, neither differentiation into myotubes nor insulin treatment changed the localization of FATP4. We conclude that FATP4 functions by its intrinsic enzymatic activity. This is in line with the concept that intracellular metabolism plays a significant role in cellular fatty acid uptake.
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Affiliation(s)
- Margarete Digel
- Molecular Cell Biology Laboratory Internal Medicine IV, University of Heidelberg, Heidelberg, Germany
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