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Liu D, Cruz-Cosme R, Wu Y, Leibowitz J, Tang Q. 2-Bromopalmitate depletes lipid droplets to inhibit viral replication. J Virol 2024; 98:e0017124. [PMID: 38488361 PMCID: PMC11019840 DOI: 10.1128/jvi.00171-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 02/26/2024] [Indexed: 04/17/2024] Open
Abstract
The global impact of emerging viral infections emphasizes the urgent need for effective broad-spectrum antivirals. The cellular organelle, lipid droplet (LD), is utilized by many types of viruses for replication, but its reduction does not affect cell survival. Therefore, LD is a potential target for developing broad-spectrum antivirals. In this study, we found that 2-bromopalmitate (2 BP), a previously defined palmitoylation inhibitor, depletes LD across all studied cell lines and exerts remarkable antiviral effects on different coronaviruses. We comprehensively utilized 2 BP, alongside other palmitoylation inhibitors such as cerulenin and 2-fluoro palmitic acid (2-FPA), as well as the enhancer palmostatin B and evaluated their impact on LD and the replication of human coronaviruses (hCoV-229E, hCoV-Oc43) and murine hepatitis virus (MHV-A59) at non-cytotoxic concentrations. While cerulenin and 2-FPA exhibited moderate inhibition of viral replication, 2 BP exhibited a much stronger suppressive effect on MHV-A59 replication, although they share similar inhibitory effects on palmitoylation. As expected, palmostatin B significantly enhanced viral replication, it failed to rescue the inhibitory effects of 2 BP, whereas it effectively counteracted the effects of cerulenin and 2-FPA. This suggests that the mechanism that 2 BP used to inhibit viral replication is beyond palmitoylation inhibition. Further investigations unveil that 2 BP uniquely depletes LDs, a phenomenon not exhibited by 2-FPA and cerulenin. Importantly, the depletion of LDs was closely associated with the inhibition of viral replication because the addition of oleic acid to 2 BP significantly rescued LD depletion and its inhibitory effects on MHV-A59. Our findings indicate that the inhibitory effects of 2 BP on viral replication primarily stem from LD disruption rather than palmitoylation inhibition. Intriguingly, fatty acid (FA) assays demonstrated that 2 BP reduces the FA level in mitochondria while concurrently increasing FA levels in the cytoplasm. These results highlight the crucial role of LDs in viral replication and uncover a novel biological activity of 2 BP. These insights contribute to the development of broad-spectrum antiviral strategies. IMPORTANCE In our study, we conducted a comparative investigation into the antiviral effects of palmitoylation inhibitors including 2-bromopalmitate (2-BP), 2-fluoro palmitic acid (2-FPA), and cerulenin. Surprisingly, we discovered that 2-BP has superior inhibitory effects on viral replication compared to 2-FPA and cerulenin. However, their inhibitory effects on palmitoylation were the same. Intrigued by this finding, we delved deeper into the underlying mechanism of 2-BP's potent antiviral activity, and we unveiled a novel biological activity of 2-BP: depletion of lipid droplets (LDs). Importantly, we also highlighted the crucial role of LDs in viral replication. Our insights shed new light on the antiviral mechanism of LD depletion paving the way for the development of broad-spectrum antiviral strategies by targeting LDs.
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Affiliation(s)
- Dongxiao Liu
- Department of Microbiology, Howard University College of Medicine, Washington, DC, USA
| | - Ruth Cruz-Cosme
- Department of Microbiology, Howard University College of Medicine, Washington, DC, USA
| | - Yong Wu
- Division of Cancer Research and Training, Department of Internal Medicine, Charles Drew University of Medicine and Science, David Geffen UCLA School of Medicine and UCLA Jonsson Comprehensive Cancer Center, Los Angeles, California, USA
| | - Julian Leibowitz
- Microbial Pathogenesis and Immunology, Texas A&M School of Medicine, Bryan, Texas, USA
| | - Qiyi Tang
- Department of Microbiology, Howard University College of Medicine, Washington, DC, USA
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Ye S, Magadán-Corpas P, Pérez-Valero Á, Villar CJ, Lombó F. Metabolic engineering strategies for naringenin production enhancement in Streptomyces albidoflavus J1074. Microb Cell Fact 2023; 22:167. [PMID: 37644530 PMCID: PMC10466684 DOI: 10.1186/s12934-023-02172-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Naringenin is an industrially relevant compound due to its multiple pharmaceutical properties as well as its central role in flavonoid biosynthesis. RESULTS On our way to develop Streptomyces albidoflavus J1074 as a microbial cell factory for naringenin production, we have significantly increased the yields of this flavanone by combining various metabolic engineering strategies, fermentation strategies and genome editing approaches in a stepwise manner. Specifically, we have screened different cultivation media to identify the optimal production conditions and have investigated how the additive feeding of naringenin precursors influences the production. Furthermore, we have employed genome editing strategies to remove biosynthetic gene clusters (BGCs) associated with pathways that might compete with naringenin biosynthesis for malonyl-CoA precursors. Moreover, we have expressed MatBC, coding for a malonate transporter and an enzyme responsible for the conversion of malonate into malonyl-CoA, respectively, and have duplicated the naringenin BGC, further contributing to the production improvement. By combining all of these strategies, we were able to achieve a remarkable 375-fold increase (from 0.06 mg/L to 22.47 mg/L) in naringenin titers. CONCLUSION This work demonstrates the influence that fermentation conditions have over the final yield of a bioactive compound of interest and highlights various bottlenecks that affect production. Once such bottlenecks are identified, different strategies can be applied to overcome them, although the efficiencies of such strategies may vary and are difficult to predict.
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Affiliation(s)
- Suhui Ye
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, Universidad de Oviedo, Oviedo, Principality of Asturias, Spain
- Principality of Asturias, IUOPA (Instituto Universitario de Oncología del Principado de Asturias), Principality of Asturias, Spain
- ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Principality of Asturias, Spain
| | - Patricia Magadán-Corpas
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, Universidad de Oviedo, Oviedo, Principality of Asturias, Spain
- Principality of Asturias, IUOPA (Instituto Universitario de Oncología del Principado de Asturias), Principality of Asturias, Spain
- ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Principality of Asturias, Spain
| | - Álvaro Pérez-Valero
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, Universidad de Oviedo, Oviedo, Principality of Asturias, Spain
- Principality of Asturias, IUOPA (Instituto Universitario de Oncología del Principado de Asturias), Principality of Asturias, Spain
- ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Principality of Asturias, Spain
| | - Claudio J Villar
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, Universidad de Oviedo, Oviedo, Principality of Asturias, Spain
- Principality of Asturias, IUOPA (Instituto Universitario de Oncología del Principado de Asturias), Principality of Asturias, Spain
- ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Principality of Asturias, Spain
| | - Felipe Lombó
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, Universidad de Oviedo, Oviedo, Principality of Asturias, Spain.
- Principality of Asturias, IUOPA (Instituto Universitario de Oncología del Principado de Asturias), Principality of Asturias, Spain.
- ISPA (Instituto de Investigación Sanitaria del Principado de Asturias), Principality of Asturias, Spain.
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Goretzki A, Lin YJ, Zimmermann J, Rainer H, Junker AC, Wolfheimer S, Vieths S, Scheurer S, Schülke S. Role of Glycolysis and Fatty Acid Synthesis in the Activation and T Cell-Modulating Potential of Dendritic Cells Stimulated with a TLR5-Ligand Allergen Fusion Protein. Int J Mol Sci 2022; 23:ijms232012695. [PMID: 36293550 PMCID: PMC9604253 DOI: 10.3390/ijms232012695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
Trained immune responses, based on metabolic and epigenetic changes in innate immune cells, are de facto innate immune memory and, therefore, are of great interest in vaccine development. In previous studies, the recombinant fusion protein rFlaA:Betv1, combining the adjuvant and toll-like receptor (TLR)5-ligand flagellin (FlaA) and the major birch pollen allergen Bet v 1 into a single molecule, significantly suppressed allergic sensitization in vivo while also changing the metabolism of myeloid dendritic cells (mDCs). Within this study, the immune-metabolic effects of rFlaA:Betv1 during mDC activation were elucidated. In line with results for other well-characterized TLR-ligands, rFlaA:Betv1 increased glycolysis while suppressing oxidative phosphorylation to different extents, making rFlaA:Betv1 a suitable model to study the immune-metabolic effects of TLR-adjuvanted vaccines. In vitro pretreatment of mDCs with cerulenin (inhibitor of fatty acid biosynthesis) led to a decrease in both rFlaA:Betv1-induced anti-inflammatory cytokine Interleukin (IL) 10 and T helper cell type (TH) 1-related cytokine IL-12p70, while the pro-inflammatory cytokine IL 1β was unaffected. Interestingly, pretreatment with the glutaminase inhibitor BPTES resulted in an increase in IL-1β, but decreased IL-12p70 secretion while leaving IL-10 unchanged. Inhibition of the glycolytic enzyme hexokinase-2 by 2-deoxyglucose led to a decrease in all investigated cytokines (IL-10, IL-12p70, and IL-1β). Inhibitors of mitochondrial respiration had no effect on rFlaA:Betv1-induced IL-10 level, but either enhanced the secretion of IL-1β (oligomycin) or decreased IL-12p70 (antimycin A). In extracellular flux measurements, mDCs showed a strongly enhanced glycolysis after rFlaA:Betv1 stimulation, which was slightly increased after respiratory shutdown using antimycin A. rFlaA:Betv1-stimulated mDCs secreted directly antimicrobial substances in a mTOR- and fatty acid metabolism-dependent manner. In co-cultures of rFlaA:Betv1-stimulated mDCs with CD4+ T cells, the suppression of Bet v 1-specific TH2 responses was shown to depend on fatty acid synthesis. The effector function of rFlaA:Betv1-activated mDCs mainly relies on glycolysis, with fatty acid synthesis also significantly contributing to rFlaA:Betv1-mediated cytokine secretion, the production of antimicrobial molecules, and the modulation of T cell responses.
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Bermeo S, Al Saedi A, Vidal C, Khalil M, Pang M, Troen BR, Myers D, Duque G. Treatment with an inhibitor of fatty acid synthase attenuates bone loss in ovariectomized mice. Bone 2019; 122:114-122. [PMID: 30779961 DOI: 10.1016/j.bone.2019.02.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/03/2019] [Accepted: 02/15/2019] [Indexed: 02/02/2023]
Abstract
Bone and fat cells have an antagonistic relationship. Adipocytes exert a toxic effect on bone cells in vitro through the secretion of fatty acids, which are synthesized by fatty acid synthase (FAS). Inhibition of FAS in vitro rescues osteoblasts from fat-induced toxicity and cell death. In this study, we hypothesized that FAS inhibition would mitigate the loss of bone mass in ovariectomized (OVX) mice. We treated OVX C57BL/6 mice with cerulenin (a known inhibitor of FAS) for 6 weeks and compared their bone phenotype with vehicle-treated controls. Cerulenin-treated mice exhibited a significant decrease in body weight, triglycerides, leptin, and marrow and subcutaneous fat without changes in serum glucose or calciotropic hormones. These effects were associated with attenuation of bone loss and normalization of the bone phenotype in the cerulenin-treated OVX group compared to the vehicle-treated OVX group. Our results demonstrate that inhibition of FAS enhances bone formation, induces uncoupling between osteoblasts and osteoclasts, and favors mineralization, thus providing evidence that inhibition of FAS could constitute a new anabolic therapy for osteoporosis.
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Affiliation(s)
- Sandra Bermeo
- Sydney Medical School Nepean, The University of Sydney, Penrith, NSW 2750, Australia; Facultad de Ciencias Básicas y Biomédicas, Universidad Simón Bolívar, Barranquilla, Colombia
| | - Ahmed Al Saedi
- Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St Albans, VIC 3021, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, St Albans, VIC 3021, Australia
| | - Christopher Vidal
- Sydney Medical School Nepean, The University of Sydney, Penrith, NSW 2750, Australia
| | - Mamdouh Khalil
- ANZAC Research Institute, Sydney Medical School Concord, The University of Sydney, Concord, NSW 2137, Australia
| | - Manhui Pang
- Division of Geriatrics and Palliative Medicine, Jacobs School of Medicine and Biomedical Sciences and Research Service, Veterans Affairs Western New York Healthcare System, University at Buffalo, Buffalo, NY, USA
| | - Bruce R Troen
- Division of Geriatrics and Palliative Medicine, Jacobs School of Medicine and Biomedical Sciences and Research Service, Veterans Affairs Western New York Healthcare System, University at Buffalo, Buffalo, NY, USA
| | - Damian Myers
- Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St Albans, VIC 3021, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, St Albans, VIC 3021, Australia
| | - Gustavo Duque
- Sydney Medical School Nepean, The University of Sydney, Penrith, NSW 2750, Australia; Australian Institute for Musculoskeletal Science (AIMSS), The University of Melbourne and Western Health, St Albans, VIC 3021, Australia; Department of Medicine-Western Health, Melbourne Medical School, The University of Melbourne, St Albans, VIC 3021, Australia.
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5
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Heredia-Martínez LG, Andrés-Garrido A, Martínez-Force E, Pérez-Pérez ME, Crespo JL. Chloroplast Damage Induced by the Inhibition of Fatty Acid Synthesis Triggers Autophagy in Chlamydomonas. Plant Physiol 2018; 178:1112-1129. [PMID: 30181343 PMCID: PMC6236622 DOI: 10.1104/pp.18.00630] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/23/2018] [Indexed: 05/19/2023]
Abstract
Fatty acids are synthesized in the stroma of plant and algal chloroplasts by the fatty acid synthase complex. Newly synthesized fatty acids are then used to generate plastidial lipids that are essential for chloroplast structure and function. Here, we show that inhibition of fatty acid synthesis in the model alga Chlamydomonas reinhardtii activates autophagy, a highly conserved catabolic process by which cells degrade intracellular material under adverse conditions to maintain cell homeostasis. Treatment of Chlamydomonas cells with cerulenin, a specific fatty acid synthase inhibitor, stimulated lipidation of the autophagosome protein ATG8 and enhanced autophagic flux. We found that inhibition of fatty acid synthesis decreased monogalactosyldiacylglycerol abundance, increased lutein content, down-regulated photosynthesis, and increased the production of reactive oxygen species. Electron microscopy revealed a high degree of thylakoid membrane stacking in cerulenin-treated cells. Moreover, global transcriptomic analysis of these cells showed an up-regulation of genes encoding chloroplast proteins involved in protein folding and oxidative stress and the induction of major catabolic processes, including autophagy and proteasome pathways. Thus, our results uncovered a link between lipid metabolism, chloroplast integrity, and autophagy through a mechanism that involves the activation of a chloroplast quality control system.
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Affiliation(s)
- Luis Gonzaga Heredia-Martínez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
| | - Ascensión Andrés-Garrido
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
| | - Enrique Martínez-Force
- Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, 41013 Seville, Spain
| | - María Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092 Seville, Spain
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6
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Richie DL, Wang L, Chan H, De Pascale G, Six DA, Wei JR, Dean CR. A pathway-directed positive growth restoration assay to facilitate the discovery of lipid A and fatty acid biosynthesis inhibitors in Acinetobacter baumannii. PLoS One 2018; 13:e0193851. [PMID: 29505586 PMCID: PMC5837183 DOI: 10.1371/journal.pone.0193851] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Accepted: 02/19/2018] [Indexed: 11/19/2022] Open
Abstract
Acinetobacter baumannii ATCC 19606 can grow without lipooligosaccharide (LOS). Lack of LOS can result from disruption of the early lipid A biosynthetic pathway genes lpxA, lpxC or lpxD. Although LOS itself is not essential for growth of A. baumannii ATCC 19606, it was previously shown that depletion of the lipid A biosynthetic enzyme LpxK in cells inhibited growth due to the toxic accumulation of lipid A pathway intermediates. Growth of LpxK-depleted cells was restored by chemical inhibition of LOS biosynthesis using CHIR-090 (LpxC) and fatty acid biosynthesis using cerulenin (FabB/F) and pyridopyrimidine (acetyl-CoA-carboxylase). Here, we expand on this by showing that inhibition of enoyl-acyl carrier protein reductase (FabI), responsible for converting trans-2-enoyl-ACP into acyl-ACP during the fatty acid elongation cycle also restored growth during LpxK depletion. Inhibition of fatty acid biosynthesis during LpxK depletion rescued growth at 37°C, but not at 30°C, whereas rescue by LpxC inhibition was temperature independent. We exploited these observations to demonstrate proof of concept for a targeted medium-throughput growth restoration screening assay to identify small molecule inhibitors of LOS and fatty acid biosynthesis. The differential temperature dependence of fatty acid and LpxC inhibition provides a simple means by which to separate growth stimulating compounds by pathway. Targeted cell-based screening platforms such as this are important for faster identification of compounds inhibiting pathways of interest in antibacterial discovery for clinically relevant Gram-negative pathogens.
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Affiliation(s)
- Daryl L. Richie
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Lisha Wang
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Helen Chan
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Gianfranco De Pascale
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - David A. Six
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Jun-Rong Wei
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
| | - Charles R. Dean
- Novartis Institutes for BioMedical Research, Emeryville, CA, United States of America
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Royle J, Donald CL, Merits A, Kohl A, Varjak M. Differential effects of lipid biosynthesis inhibitors on Zika and Semliki Forest viruses. Vet J 2017; 230:62-64. [PMID: 29102599 PMCID: PMC5726355 DOI: 10.1016/j.tvjl.2017.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 09/11/2017] [Accepted: 10/17/2017] [Indexed: 11/29/2022]
Abstract
The recent outbreak of infection with Zika virus (ZIKV; Flaviviridae) has attracted attention to this previously neglected mosquito-borne pathogen and the need for efficient therapies. Since flavivirus replication is generally known to be dependent on fatty acid biosynthesis, two inhibitors of this pathway, 5-(tetradecyloxyl)-2-furoic acid (TOFA) and cerulenin, were tested for their potentiality to inhibit virus replication. At concentrations previously shown to inhibit the replication of other flaviviruses, neither drug had a significant antiviral affect against ZIKV, but reduced the replication of the non-related mosquito-borne Semliki Forest virus (Togaviridae).
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Affiliation(s)
- Jamie Royle
- MRC -University of Glasgow Centre for Virus Research, Glasgow G61 1QH, Scotland, UK
| | - Claire L Donald
- MRC -University of Glasgow Centre for Virus Research, Glasgow G61 1QH, Scotland, UK
| | - Andres Merits
- Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia
| | - Alain Kohl
- MRC -University of Glasgow Centre for Virus Research, Glasgow G61 1QH, Scotland, UK
| | - Margus Varjak
- MRC -University of Glasgow Centre for Virus Research, Glasgow G61 1QH, Scotland, UK.
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Zhang J, Burgess JG. Enhanced eicosapentaenoic acid production by a new deep-sea marine bacterium Shewanella electrodiphila MAR441T. PLoS One 2017; 12:e0188081. [PMID: 29176835 PMCID: PMC5703452 DOI: 10.1371/journal.pone.0188081] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 10/31/2017] [Indexed: 02/05/2023] Open
Abstract
Omega-3 fatty acids are products of secondary metabolism, essential for growth and important for human health. Although there are numerous reports of bacterial production of omega-3 fatty acids, less information is available on the biotechnological production of these compounds from bacteria. The production of eicosapentaenoic acid (EPA, 20:5ω3) by a new species of marine bacteria Shewanella electrodiphila MAR441T was investigated under different fermentation conditions. This strain produced a high percentage (up to 26%) of total fatty acids and high yields (mg / g of biomass) of EPA at or below the optimal growth temperature. At higher growth temperatures these values decreased greatly. The amount of EPA produced was affected by the carbon source, which also influenced fatty acid composition. This strain required Na+ for growth and EPA synthesis and cells harvested at late exponential or early stationary phase had a higher EPA content. Both the highest amounts (20 mg g-1) and highest percent EPA content (18%) occurred with growth on L-proline and (NH4)2SO4. The addition of cerulenin further enhanced EPA production to 30 mg g-1. Chemical mutagenesis using NTG allowed the isolation of mutants with improved levels of EPA content (from 9.7 to 15.8 mg g-1) when grown at 15°C. Thus, the yields of EPA could be substantially enhanced without the need for recombinant DNA technology, often a commercial requirement for food supplement manufacture.
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Affiliation(s)
- Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratory, Exeter, United Kingdom
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - J. Grant Burgess
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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Nickels JD, Chatterjee S, Stanley CB, Qian S, Cheng X, Myles DAA, Standaert RF, Elkins JG, Katsaras J. The in vivo structure of biological membranes and evidence for lipid domains. PLoS Biol 2017; 15:e2002214. [PMID: 28542493 PMCID: PMC5441578 DOI: 10.1371/journal.pbio.2002214] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/11/2017] [Indexed: 12/19/2022] Open
Abstract
Examining the fundamental structure and processes of living cells at the nanoscale poses a unique analytical challenge, as cells are dynamic, chemically diverse, and fragile. A case in point is the cell membrane, which is too small to be seen directly with optical microscopy and provides little observational contrast for other methods. As a consequence, nanoscale characterization of the membrane has been performed ex vivo or in the presence of exogenous labels used to enhance contrast and impart specificity. Here, we introduce an isotopic labeling strategy in the gram-positive bacterium Bacillus subtilis to investigate the nanoscale structure and organization of its plasma membrane in vivo. Through genetic and chemical manipulation of the organism, we labeled the cell and its membrane independently with specific amounts of hydrogen (H) and deuterium (D). These isotopes have different neutron scattering properties without altering the chemical composition of the cells. From neutron scattering spectra, we confirmed that the B. subtilis cell membrane is lamellar and determined that its average hydrophobic thickness is 24.3 ± 0.9 Ångstroms (Å). Furthermore, by creating neutron contrast within the plane of the membrane using a mixture of H- and D-fatty acids, we detected lateral features smaller than 40 nm that are consistent with the notion of lipid rafts. These experiments-performed under biologically relevant conditions-answer long-standing questions in membrane biology and illustrate a fundamentally new approach for systematic in vivo investigations of cell membrane structure.
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Affiliation(s)
- Jonathan D. Nickels
- Shull Wollan Center—A Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Sneha Chatterjee
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Christopher B. Stanley
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Shuo Qian
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Xiaolin Cheng
- Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Dean A. A. Myles
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Robert F. Standaert
- Shull Wollan Center—A Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail: (RFS); (JGE); (JK)
| | - James G. Elkins
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail: (RFS); (JGE); (JK)
| | - John Katsaras
- Shull Wollan Center—A Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail: (RFS); (JGE); (JK)
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10
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Peng YF, Chen WC, Xiao K, Xu L, Wang L, Wan X. DHA Production in Escherichia coli by Expressing Reconstituted Key Genes of Polyketide Synthase Pathway from Marine Bacteria. PLoS One 2016; 11:e0162861. [PMID: 27649078 PMCID: PMC5029812 DOI: 10.1371/journal.pone.0162861] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/30/2016] [Indexed: 12/30/2022] Open
Abstract
The gene encoding phosphopantetheinyl transferase (PPTase), pfaE, a component of the polyketide synthase (PKS) pathway, is crucial for the production of docosahexaenoic acid (DHA, 22:6ω3), along with the other pfa cluster members pfaA, pfaB, pfaC and pfaD. DHA was produced in Escherichia coli by co-expressing pfaABCD from DHA-producing Colwellia psychrerythraea 34H with one of four pfaE genes from bacteria producing arachidonic acid (ARA, 20:4ω6), eicosapentaenoic acid (EPA, 20:5ω3) or DHA, respectively. Substitution of the pfaE gene from different strain source in E. coli did not influence the function of the PKS pathway producing DHA, although they led to different DHA yields and fatty acid profiles. This result suggested that the pfaE gene could be switchable between these strains for the production of DHA. The DHA production by expressing the reconstituted PKS pathway was also investigated in different E. coli strains, at different temperatures, or with the treatment of cerulenin. The highest DHA production, 2.2 mg of DHA per gram of dry cell weight or 4.1% of total fatty acids, was obtained by co-expressing pfaE(EPA) from the EPA-producing strain Shewanella baltica with pfaABCD in DH5α. Incubation at low temperature (10–15°C) resulted in higher accumulation of DHA compared to higher temperatures. The addition of cerulenin to the medium increased the proportion of DHA and saturated fatty acids, including C12:0, C14:0 and C16:0, at the expense of monounsaturated fatty acids, including C16:1 and C18:1. Supplementation with 1 mg/L cerulenin resulted in the highest DHA yield of 2.4 mg/L upon co-expression of pfaE(DHA) from C. psychrerythraea.
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Affiliation(s)
- Yun-Feng Peng
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Wen-Chao Chen
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Kang Xiao
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Lin Xu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Lian Wang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Xia Wan
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
- Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, China
- * E-mail:
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11
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Yasumoto Y, Miyazaki H, Vaidyan LK, Kagawa Y, Ebrahimi M, Yamamoto Y, Ogata M, Katsuyama Y, Sadahiro H, Suzuki M, Owada Y. Inhibition of Fatty Acid Synthase Decreases Expression of Stemness Markers in Glioma Stem Cells. PLoS One 2016; 11:e0147717. [PMID: 26808816 PMCID: PMC4726602 DOI: 10.1371/journal.pone.0147717] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/13/2015] [Indexed: 12/14/2022] Open
Abstract
Cellular metabolic changes, especially to lipid metabolism, have recently been recognized as a hallmark of various cancer cells. However, little is known about the significance of cellular lipid metabolism in the regulation of biological activity of glioma stem cells (GSCs). In this study, we examined the expression and role of fatty acid synthase (FASN), a key lipogenic enzyme, in GSCs. In the de novo lipid synthesis assay, GSCs exhibited higher lipogenesis than differentiated non-GSCs. Western blot and immunocytochemical analyses revealed that FASN is strongly expressed in multiple lines of patient-derived GSCs (G144 and Y10), but its expression was markedly reduced upon differentiation. When GSCs were treated with 20 μM cerulenin, a pharmacological inhibitor of FASN, their proliferation and migration were significantly suppressed and de novo lipogenesis decreased. Furthermore, following cerulenin treatment, expression of the GSC markers nestin, Sox2 and fatty acid binding protein (FABP7), markers of GCSs, decreased while that of glial fibrillary acidic protein (GFAP) expression increased. Taken together, our results indicate that FASN plays a pivotal role in the maintenance of GSC stemness, and FASN-mediated de novo lipid biosynthesis is closely associated with tumor growth and invasion in glioblastoma.
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Affiliation(s)
- Yuki Yasumoto
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hirofumi Miyazaki
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Linda Koshy Vaidyan
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yoshiteru Kagawa
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Majid Ebrahimi
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yui Yamamoto
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Masaki Ogata
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yu Katsuyama
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hirokazu Sadahiro
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Michiyasu Suzuki
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yuji Owada
- Department of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Ube, Japan
- Department of Organ Anatomy, Tohoku University Graduate School of Medicine, Sendai, Japan
- * E-mail:
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12
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Hashimoto M, Komatsu K, Iwai R, Keima T, Maejima K, Shiraishi T, Ishikawa K, Yoshida T, Kitazawa Y, Okano Y, Yamaji Y, Namba S. Cell Death Triggered by a Putative Amphipathic Helix of Radish mosaic virus Helicase Protein Is Tightly Correlated With Host Membrane Modification. Mol Plant Microbe Interact 2015; 28:675-88. [PMID: 25650831 DOI: 10.1094/mpmi-01-15-0004-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Systemic necrosis is one of the most severe symptoms caused by plant RNA viruses. Recently, systemic necrosis has been suggested to have similar features to a defense response referred to as the hypersensitive response (HR), a form of programmed cell death. In virus-infected plant cells, host intracellular membrane structures are changed dramatically for more efficient viral replication. However, little is known about whether this replication-associated membrane modification is the cause of the symptoms. In this study, we identified an amino-terminal amphipathic helix of the helicase encoded by Radish mosaic virus (RaMV) (genus Comovirus) as an elicitor of cell death in RaMV-infected plants. Cell death caused by the amphipathic helix had features similar to HR, such as SGT1-dependence. Mutational analyses and inhibitor assays using cerulenin demonstrated that the amphipathic helix-induced cell death was tightly correlated with dramatic alterations in endoplasmic reticulum (ER) membrane structures. Furthermore, the cell death-inducing activity of the amphipathic helix was conserved in Cowpea mosaic virus (genus Comovirus) and Tobacco ringspot virus (genus Nepovirus), both of which are classified in the family Secoviridae. Together, these results indicate that ER membrane modification associated with viral intracellular replication may be recognized to prime defense responses against plant viruses.
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Affiliation(s)
- Masayoshi Hashimoto
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Ken Komatsu
- 2 Laboratory of Plant Pathology, Tokyo University of Agriculture and Technology (TUAT), 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Ryo Iwai
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takuya Keima
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kensaku Maejima
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takuya Shiraishi
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kazuya Ishikawa
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tetsuya Yoshida
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yugo Kitazawa
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yukari Okano
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasuyuki Yamaji
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shigetou Namba
- 1 Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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13
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Yellen P, Foster DA. Inhibition of fatty acid synthase induces pro-survival Akt and ERK signaling in K-Ras-driven cancer cells. Cancer Lett 2014; 353:258-63. [PMID: 25086185 DOI: 10.1016/j.canlet.2014.07.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 07/15/2014] [Accepted: 07/16/2014] [Indexed: 01/04/2023]
Abstract
Cancer cells with constitutive phosphatidylinositol 3-kinase (PI3K)/Akt pathway activation have been associated with overexpression of the lipogenic enzyme fatty acid synthase (FAS) as a means to provide lipids necessary for cell growth. In contrast, K-Ras-driven cancer cells suppress utilization of de novo synthesized fatty acids and rely on exogenously supplied fatty acids for cell growth and membrane phospholipid biosynthesis. Consistent with a differential need for de novo fatty acid synthesis, cancer cells with activated PI3K signaling were sensitive to suppression of FAS; whereas mutant K-Ras-driven cancer cells continued to proliferate with suppressed FAS. Surprisingly, in response to FAS suppression, we observed robust increases in both Akt and ERK phosphorylation. Akt phosphorylation was dependent on the insulin-like growth factor-1 receptor (IGF-1R)/PI3K pathway and mTOR complex 2. Intriguingly, K-Ras-mediated ERK activation was dependent on N-Ras. Pharmacological inhibition of PI3K and MEK in K-Ras-driven cancer cells resulted in increased sensitivity to FAS inhibition. These data reveal a surprising sensitivity of K-Ras-driven cancer cells to FAS suppression when stimulation of Akt and ERK was prevented. As K-Ras-driven cancers are notoriously difficult to treat, these findings have therapeutic implications.
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Affiliation(s)
- Paige Yellen
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY, USA
| | - David A Foster
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY, USA.
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14
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Rossato FA, Zecchin KG, La Guardia PG, Ortega RM, Alberici LC, Costa RAP, Catharino RR, Graner E, Castilho RF, Vercesi AE. Fatty acid synthase inhibitors induce apoptosis in non-tumorigenic melan-a cells associated with inhibition of mitochondrial respiration. PLoS One 2014; 9:e101060. [PMID: 24964211 PMCID: PMC4071076 DOI: 10.1371/journal.pone.0101060] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/03/2014] [Indexed: 12/31/2022] Open
Abstract
The metabolic enzyme fatty acid synthase (FASN) is responsible for the endogenous synthesis of palmitate, a saturated long-chain fatty acid. In contrast to most normal tissues, a variety of human cancers overexpress FASN. One such cancer is cutaneous melanoma, in which the level of FASN expression is associated with tumor invasion and poor prognosis. We previously reported that two FASN inhibitors, cerulenin and orlistat, induce apoptosis in B16-F10 mouse melanoma cells via the intrinsic apoptosis pathway. Here, we investigated the effects of these inhibitors on non-tumorigenic melan-a cells. Cerulenin and orlistat treatments were found to induce apoptosis and decrease cell proliferation, in addition to inducing the release of mitochondrial cytochrome c and activating caspases-9 and -3. Transfection with FASN siRNA did not result in apoptosis. Mass spectrometry analysis demonstrated that treatment with the FASN inhibitors did not alter either the mitochondrial free fatty acid content or composition. This result suggests that cerulenin- and orlistat-induced apoptosis events are independent of FASN inhibition. Analysis of the energy-linked functions of melan-a mitochondria demonstrated the inhibition of respiration, followed by a significant decrease in mitochondrial membrane potential (ΔΨm) and the stimulation of superoxide anion generation. The inhibition of NADH-linked substrate oxidation was approximately 40% and 61% for cerulenin and orlistat treatments, respectively, and the inhibition of succinate oxidation was approximately 46% and 52%, respectively. In contrast, no significant inhibition occurred when respiration was supported by the complex IV substrate N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). The protection conferred by the free radical scavenger N-acetyl-cysteine indicates that the FASN inhibitors induced apoptosis through an oxidative stress-associated mechanism. In combination, the present results demonstrate that cerulenin and orlistat induce apoptosis in non-tumorigenic cells via mitochondrial dysfunction, independent of FASN inhibition.
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Affiliation(s)
- Franco A. Rossato
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Karina G. Zecchin
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
- Departamento de Diagnóstico Oral, Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP, Brazil
| | - Paolo G. La Guardia
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Rose M. Ortega
- Departamento de Diagnóstico Oral, Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP, Brazil
| | - Luciane C. Alberici
- Departamento de Química e Física, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Rute A. P. Costa
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Rodrigo R. Catharino
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Edgard Graner
- Departamento de Diagnóstico Oral, Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP, Brazil
| | - Roger F. Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
| | - Aníbal E. Vercesi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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15
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Yan C, Wei H, Minjuan Z, Yan X, Jingyue Y, Wenchao L, Sheng H. The mTOR inhibitor rapamycin synergizes with a fatty acid synthase inhibitor to induce cytotoxicity in ER/HER2-positive breast cancer cells. PLoS One 2014; 9:e97697. [PMID: 24866893 PMCID: PMC4035285 DOI: 10.1371/journal.pone.0097697] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 04/23/2014] [Indexed: 12/20/2022] Open
Abstract
Patients with ER/HER2-positive breast cancer have a poor prognosis and are less responsive to selective estrogen receptor modulators; this is presumably due to the crosstalk between ER and HER2. Fatty acid synthase (FASN) is essential for the survival and maintenance of the malignant phenotype of breast cancer cells. An intimate relationship exists between FASN, ER and HER2. We hypothesized that FASN may be the downstream effector underlying ER/HER2 crosstalk through the PI3K/AKT/mTOR pathway in ER/HER2-positive breast cancer. The present study implicated the PI3K/AKT/mTOR pathway in the regulation of FASN expression in ER/HER2-positive breast cancer cells and demonstrated that rapamycin, an mTOR inhibitor, inhibited FASN expression. Cerulenin, a FASN inhibitor, synergized with rapamycin to induce apoptosis and inhibit cell migration and tumorigenesis in ER/HER2-positive breast cancer cells. Our findings suggest that inhibiting the mTOR-FASN axis is a promising new strategy for treating ER/HER2-positive breast cancer.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Blotting, Western
- Breast Neoplasms/drug therapy
- Breast Neoplasms/enzymology
- Breast Neoplasms/pathology
- Cell Movement/drug effects
- Cell Proliferation/drug effects
- Cerulenin/pharmacology
- Drug Synergism
- Estrogen Receptor alpha/genetics
- Estrogen Receptor alpha/metabolism
- Fatty Acid Synthase, Type I/antagonists & inhibitors
- Fatty Acid Synthase, Type I/genetics
- Fatty Acid Synthase, Type I/metabolism
- Female
- Fluorescent Antibody Technique, Indirect
- Gene Expression Regulation, Neoplastic/drug effects
- Humans
- Mice
- Mice, Nude
- Protein Kinase Inhibitors/pharmacology
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sirolimus/pharmacology
- Tumor Cells, Cultured
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Chen Yan
- Department of Oncology, Xi'jing Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Huang Wei
- Department of Cardiology, Xi'jing hospital, Fourth military medical university, Xi'an, PR China
| | - Zheng Minjuan
- Department of Ultrasound, Xi'jing Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Xue Yan
- Department of Oncology, Xi'jing Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Yang Jingyue
- Department of Oncology, Xi'jing Hospital, Fourth Military Medical University, Xi'an, PR China
| | - Liu Wenchao
- Department of Oncology, Xi'jing Hospital, Fourth Military Medical University, Xi'an, PR China
- * E-mail: (LW); (HS)
| | - Han Sheng
- State Key Laboratory of Military Stomatology, Department of Information Center, School of Stomatology, Fourth Military Medical University, Xi'an, PR China
- * E-mail: (LW); (HS)
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16
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Hashimoto KI, Kawasaki H, Akazawa K, Nakamura J, Asakura Y, Kudo T, Sakuradani E, Shimizu S, Nakamatsu T. Changes in Composition and Content of Mycolic Acids in Glutamate-OverproducingCorynebacterium glutamicum. Biosci Biotechnol Biochem 2014; 70:22-30. [PMID: 16428817 DOI: 10.1271/bbb.70.22] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Overproduction of glutamate by Corynebacterium glutamicum is induced by biotin limitation or by the supplementation of specific detergents, sublethal amounts of penicillin, or cerulenin. But, it remains unclear why these different treatments, which have different sites of primary action, produce similar effects. In this study, it was found that the cellular content of mycolic acids--characteristic constituents of Corynebacterineae that are synthesized from fatty acids and form a cell surface layer--decreased under all conditions that induced glutamate overproduction. Furthermore, short mycolic acids increased under conditions of biotin limitation and cerulenin supplementation. These results suggest that different treatments produce the same effect that causes defects in the mycolic acid layer. This is perhaps one of the key factors in overproduction of glutamate by C. glutamicum.
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Affiliation(s)
- Ken-ichi Hashimoto
- Department of Environmental Materials Science, Tokyo Denki University, Japan
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17
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Cheng G, Palanisamy AP, Evans ZP, Sutter AG, Jin L, Singh I, May H, Schmidt MG, Chavin KD. Cerulenin blockade of fatty acid synthase reverses hepatic steatosis in ob/ob mice. PLoS One 2013; 8:e75980. [PMID: 24086674 PMCID: PMC3785413 DOI: 10.1371/journal.pone.0075980] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/18/2013] [Indexed: 12/14/2022] Open
Abstract
Fatty liver or hepatic steatosis is a common health problem associated with abnormal liver function and increased susceptibility to ischemia/reperfusion injury. The objective of this study was to investigate the effect of the fatty acid synthase inhibitor cerulenin on hepatic function in steatotic ob/ob mice. Different dosages of cerulenin were administered intraperitoneally to ob/ob mice for 2 to 7 days. Body weight, serum AST/ALT, hepatic energy state, and gene expression patterns in ob/ob mice were examined. We found that cerulenin treatment markedly improved hepatic function in ob/ob mice. Serum AST/ALT levels were significantly decreased and hepatic ATP levels increased in treated obese mice compared to obese controls, accompanied by fat depletion in the hepatocyte. Expression of peroxisome proliferator-activated receptors α and γ and uncoupling protein 2 were suppressed with cerulenin treatment and paralleled changes in AST/ALT levels. Hepatic glutathione content were increased in some cases and apoptotic activity in the steatotic livers was minimally changed with cerulenin treatment. In conclusion, these results demonstrate that fatty acid synthase blockade constitutes a novel therapeutic strategy for altering hepatic steatosis at non-stressed states in obese livers.
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Affiliation(s)
- Gang Cheng
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Arun P. Palanisamy
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
| | - Zachary P. Evans
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Alton G. Sutter
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Lan Jin
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Inderjit Singh
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Harold May
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Michael G. Schmidt
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Kenneth D. Chavin
- Divisions of Transplant Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina, United States of America
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18
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Wang LH, Lee HH, Fang LS, Mayfield AB, Chen CS. Fatty acid and phospholipid syntheses are prerequisites for the cell cycle of Symbiodinium and their endosymbiosis within sea anemones. PLoS One 2013; 8:e72486. [PMID: 24009685 PMCID: PMC3756969 DOI: 10.1371/journal.pone.0072486] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 07/10/2013] [Indexed: 11/30/2022] Open
Abstract
Lipids are a source of metabolic energy, as well as essential components of cellular membranes. Although they have been shown to be key players in the regulation of cell proliferation in various eukaryotes, including microalgae, their role in the cell cycle of cnidarian-dinoflagellate (genus Symbiodinium) endosymbioses remains to be elucidated. The present study examined the effects of a lipid synthesis inhibitor, cerulenin, on the cell cycle of both cultured Symbiodinium (clade B) and those engaged in an endosymbiotic association with the sea anemone Aiptasia pulchella. In the former, cerulenin exposure was found to inhibit free fatty acid (FFA) synthesis, as it does in other organisms. Additionally, while it also significantly inhibited the synthesis of phosphatidylethanolamine (PE), it did not affect the production of sterol ester (SE) or phosphatidylcholine (PC). Interestingly, cerulenin also significantly retarded cell division by arresting the cell cycles at the G0/G1 phase. Cerulenin-treated Symbiodinium were found to be taken up by anemone hosts at a significantly depressed quantity in comparison with control Symbiodinium. Furthermore, the uptake of cerulenin-treated Symbiodinium in host tentacles occurred much more slowly than in untreated controls. These results indicate that FFA and PE may play critical roles in the recognition, proliferation, and ultimately the success of endosymbiosis with anemones.
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Affiliation(s)
- Li-Hsueh Wang
- National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
- Graduate Institute of Marine Biotechnology, National Dong Hwa University, Hualien, Taiwan
| | - Hsieh-He Lee
- Graduate Institute of Marine Biotechnology, National Dong Hwa University, Hualien, Taiwan
| | - Lee-Shing Fang
- Department of Sport, Health and Leisure Studies, Cheng Shiu University, Kaohsiung, Taiwan
| | - Anderson B. Mayfield
- National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
- Living Oceans Foundation, Landover, Maryland, United States of America
| | - Chii-Shiarng Chen
- National Museum of Marine Biology and Aquarium, Checheng, Pingtung, Taiwan
- Graduate Institute of Marine Biotechnology, National Dong Hwa University, Hualien, Taiwan
- Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan
- * E-mail:
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Yitzhaki S, Rostron JE, Xu Y, Rideout MC, Authement RN, Barlow SB, Segall AM. Similarities between exogenously- and endogenously-induced envelope stress: the effects of a new antibacterial molecule, TPI1609-10. PLoS One 2012; 7:e44896. [PMID: 23071502 PMCID: PMC3469575 DOI: 10.1371/journal.pone.0044896] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 08/15/2012] [Indexed: 11/19/2022] Open
Abstract
Antibiotics with novel and/or multiple targets are highly desirable in the face of the steady rise of clinical antibiotic resistance. We have screened and identified small molecules, typified by the compound TPI1609-10 (aka SM10), with antibiotic activity against both gram-positive and gram-negative bacteria. SM10 was screened in vitro to bind branched Holliday junction intermediates of homologous recombination and tyrosine recombinase-mediated recombination; thus, the cellular targets of the small molecules were expected to include the RuvABC Holliday junction resolvasome and the XerCD complex involved in proper segregation of replicated chromosomes to daughter cells. SM10 indeed induces DNA damage and filamentation in E. coli. However, SM10 also induces envelope stress and causes increased production of intracellular reactive oxygen species. In addition, SM10 has similar effects to endogenously-induced envelope stress via overproducing outer membrane proteins (OmpC and OmpF), which also induces the SOS response, chromosome fragmentation, and production of reactive oxygen species. The synergy between SM10, and cerulenin, a fatty acid synthesis inhibitor, together with the SM10 hypersensitivity of cpx and rpoE mutants, further support that SM10's mode of action damages membrane damage. The lethality of SM10 treatment and of OmpC overproduction are observed in both aerobically- and anaerobically-grown cells, and is accompanied by substantial DNA damage even anaerobically. Thus, only some DNA damage is due to reactive oxygen. We propose that membrane depolarization and the potential reduction in intracellular pH, leading to abasic site formation, cause a substantial amount of the DNA damage associated with both SM10 treatment and endogenous envelope stress. While it is difficult to completely exclude effects related to envelope damage as the sources of DNA damage, trapping intermediates associated with DNA repair and chromosome segregation pathways remains very likely. Thus SM10 may have distinct but synergistic modes of action.
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Affiliation(s)
- Shmuel Yitzhaki
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Jason E. Rostron
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Yan Xu
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Marc C. Rideout
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - R. Nathan Authement
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Steven B. Barlow
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
- Electron Microscopy Facility, San Diego State University, San Diego, California, United States of America
| | - Anca M. Segall
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
- * E-mail:
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20
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Jiang B, Li EH, Lu YY, Jiang Q, Cui D, Jing YF, Xia SJ. Inhibition of fatty-acid synthase suppresses P-AKT and induces apoptosis in bladder cancer. Urology 2012; 80:484.e9-15. [PMID: 22554590 DOI: 10.1016/j.urology.2012.02.046] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 02/02/2012] [Accepted: 02/27/2012] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate the role of fatty acid synthase (FASN) in bladder transitional cell carcinoma (BTCC). METHODS FASN expression was investigated in non-muscle-invasive BTCC tissue specimens by immunohistochemistry and BTCC cell lines by Western blot. After treatment with FASN-siRNA or FASN inhibitor cerulenin (Cer), the proliferation and apoptosis of BTCC cell lines 5637 and 253 J were determined by cell counting Kit-8 (CCK8) assay and flow cytometry respectively. The expression of p-AKT, cyclin D1 (CCND1), and apoptosis-related proteins were detected by Western blot. RESULTS High levels of FASN expression were observed in 59% (32/54) of non-muscle-invasive BTCC tissue specimens, and FASN expression was associated with histologic grade (P < .05) and recurrence (P < .05). FASN expression was high in 6 BTCC cell lines. FASN inhibitor Cer and FASN-siRNA produced the increased apoptosis and decreased proliferation of bladder cancer cells, and caused inactivity of AKT and downregulation of CCND1. Furthermore, treatment of BTCC cell lines with Cer resulted in apoptosis via the caspase-dependent pathway involving inactivation of antiapoptotic bcl-2 protein. CONCLUSION Our data suggest that FASN plays an important role in BTCC development. Targeting FASN may be a new therapeutic strategy for BTCC.
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Affiliation(s)
- Bo Jiang
- Department of Urology, The Affiliated First People's Hospital of Shanghai Jiao Tong University, School of Medicine, Shanghai, China
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21
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Kotaka A, Sahara H, Hata Y. The construction and application of diploid sake yeast with a homozygous mutation in the FAS2 gene. J Biosci Bioeng 2010; 110:675-8. [PMID: 20708434 DOI: 10.1016/j.jbiosc.2010.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 11/18/2022]
Abstract
In Japanese sake brewing, cerulenin-resistant sake yeasts produce elevated levels of ethyl caproate, an important flavor component. The FAS2 mutation FAS2-1250S of Saccharomyces cerevisiae generates a cerulenin-resistant phenotype. This mutation is dominant, and, in general, cerulenin-resistant diploid sake yeast strains carry this mutation heterozygously. Here we constructed diploid sake yeast with a homozygous mutation of FAS2 using the high-efficiency loss of heterozygosity method. The homozygous mutants grew more slowly in YPD medium than did the wild-type and heterozygous mutants, and they produced more ethyl caproate during sake brewing. In addition, although both the wild-type and heterozygous mutant were sensitive to 4 mg/l cerulenin, the homozygous mutant was resistant to more than 4 mg/l cerulenin. Next, we obtained a homozygous mutant of FAS2 without inducing genetic modification. After cultivating the heterozygous FAS2 mutant K-1801 in YPD, homozygous mutants were selected on medium containing high concentrations of cerulenin. Non-genetically modified yeast with a homozygous mutation of FAS2 produced 2.2-fold more ethyl caproate than did heterozygous yeast. Moreover, high-quality Japanese sake with a very rich flavor could be brewed using yeast containing a homozygous mutation in the FAS2 gene.
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Affiliation(s)
- Atsushi Kotaka
- Research Institute, Gekkeikan Sake Co. Ltd., 101 Shimotoba-koyanagi-cho, Fushimi-ku, Kyoto 612-8385, Japan.
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22
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Elbaz A, Wu X, Rivas D, Gimble JM, Duque G. Inhibition of fatty acid biosynthesis prevents adipocyte lipotoxicity on human osteoblasts in vitro. J Cell Mol Med 2010; 14:982-91. [PMID: 19382912 PMCID: PMC2891630 DOI: 10.1111/j.1582-4934.2009.00751.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 03/10/2009] [Indexed: 01/08/2023] Open
Abstract
Although increased bone marrow fat in age-related bone loss has been associated with lower trabecular mass, the underlying mechanism responsible remains unknown. We hypothesized that marrow adipocytes exert a lipotoxic effect on osteoblast function and survival through the reversible biosynthesis of fatty acids (FA) into the bone marrow microenvironment. We have used a two-chamber system to co-culture normal human osteoblasts (NHOst) with differentiating pre-adipocytes in the absence or presence of an inhibitor of FA synthase (cerulenin) and separated by an insert that allowed unidirectional trafficking of soluble factors only and prevented direct cell-cell contact. Supernatants were assayed for the presence of FA using mass spectophotometry. After 3 weeks in co-culture, NHOst showed significantly lower levels of differentiation and function based on lower mineralization and expression of alkaline phosphatase, osterix, osteocalcin and Runx2. In addition, NHOst survival was affected by the presence of adipocytes as determined by MTS-formazan and TUNEL assays as well as higher activation of caspases 3/7. These toxic effects were inhibited by addition of cerulenin. Furthermore, culture of NHOst with either adipocyte-conditioned media alone in the absence of adipocytes themselves or with the addition of the most predominant FA (stearate or palmitate) produced similar toxic results. Finally, Runx2 nuclear binding was affected by addition of either adipocyte conditioned media or FA into the osteogenic media. We conclude that the presence of FA within the marrow milieu can contribute to the age-related changes in bone mass and can be prevented by the inhibition of FA synthase.
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Affiliation(s)
- Alexandre Elbaz
- Lady Davis Institute for Medical Research, McGill University, MontrealQuebec, Canada
| | - Xiying Wu
- Stem Cell Laboratory, Pennington Biomedical Research CenterBaton Rouge, LA, USA
| | - Daniel Rivas
- Lady Davis Institute for Medical Research, McGill University, MontrealQuebec, Canada
| | - Jeffrey M Gimble
- Stem Cell Laboratory, Pennington Biomedical Research CenterBaton Rouge, LA, USA
| | - Gustavo Duque
- Lady Davis Institute for Medical Research, McGill University, MontrealQuebec, Canada
- Aging Bone Research Program, Nepean Clinical School, University of SydneyPenrith, NSW, Australia
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Ons E, Gertler A, Buyse J, Lebihan-Duval E, Bordas A, Goddeeris B, Dridi S. Visfatin gene expression in chickens is sex and tissue dependent. Domest Anim Endocrinol 2010; 38:63-74. [PMID: 19786337 DOI: 10.1016/j.domaniend.2009.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 08/12/2009] [Accepted: 08/28/2009] [Indexed: 01/17/2023]
Abstract
The present study investigated the expression of visfatin mRNA in various tissues of male and female broiler chickens. We also studied the effect of leptin, cerulenin, and food deprivation, known effectors of energy balance and insulin action, on visfatin gene expression in chickens. Using reverse transcription polymerase chain reaction (RT-PCR) and Northern blot analysis, we detected chicken visfatin mRNA transcript in the kidney, hypothalamus, gizzard, liver, pancreas, proventriculus, breast and leg muscle, ovary, testis, lung, intestine, adipose tissue, and heart. Expression of the visfatin gene in various tissues of male and female chickens was determined by real-time quantitative PCR and found to be tissue and sex dependent. In both sexes, compared to other tissues, the visfatin gene is highly expressed in the muscle. Females exhibited greater (P<0.001) abundance of visfatin mRNA in adipose tissue compared to males, whereas compared to females, males showed greater (P<0.05) visfatin mRNA abundance in the kidney. Also, the regulation of visfatin gene expression by leptin, cerulenin, and food deprivation is tissue specific. Leptin decreased (P<0.05) visfatin mRNA abundance in the liver and hypothalamus, but not in muscle. In contrast, cerulenin increased (P<0.01) visfatin gene expression in the liver and in muscle, but not in the hypothalamus. Interestingly, visfatin mRNA levels increased (P<0.05) in the liver after 24-h food deprivation, but not in muscle or in the hypothalamus of genetically selected fat and lean line chickens. Our results showed that the visfatin gene is ubiquitously expressed in chickens with greater abundance in muscle, and that it is regulated in a tissue-specific manner by energy balance-related factors.
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Affiliation(s)
- E Ons
- Laboratory of Livestock Physiology, Immunology, and Genetics, Department of Biosystems, KU Leuven, 3001 Leuven, Belgium
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Bamunusinghe D, Hemenway CL, Nelson RS, Sanderfoot AA, Ye CM, Silva MAT, Payton M, Verchot-Lubicz J. Analysis of potato virus X replicase and TGBp3 subcellular locations. Virology 2009; 393:272-85. [PMID: 19729179 DOI: 10.1016/j.virol.2009.08.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/09/2009] [Accepted: 08/02/2009] [Indexed: 10/20/2022]
Abstract
Potato virus X (PVX) infection leads to certain cytopathological modifications of the host endomembrane system. The subcellular location of the PVX replicase was previously unknown while the PVX TGBp3 protein was previously reported to reside in the ER. Using PVX infectious clones expressing the green fluorescent protein reporter, and antisera detecting the PVX replicase and host membrane markers, we examined the subcellular distribution of the PVX replicase in relation to the TGBp3. Confocal and electron microscopic observations revealed that the replicase localizes in membrane bound structures that derive from the ER. A subset of TGBp3 resides in the ER at the same location as the replicase. Sucrose gradient fractionation showed that the PVX replicase and TGBp3 proteins co-fractionate with ER marker proteins. This localization represents a region where both proteins may be synthesized and/or function. There is no evidence to indicate that either PVX protein moves into the Golgi apparatus. Cerulenin, a drug that inhibits de novo membrane synthesis, also inhibited PVX replication. These combined data indicate that PVX replication relies on ER-derived membrane recruitment and membrane proliferation.
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Affiliation(s)
- Devinka Bamunusinghe
- Department of Entomology and Plant Pathology, Noble Research Center, Oklahoma State University, Stillwater, OK 74078, USA.
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Oohata AA, Fukuzawa M, Hotta R, Nakagawa M, Niwa M, Takaya Y. Differentiation inducing factors in Dictyostelium discoideum: A novel low molecular factor functions at an early stage(s) of differentiation. Dev Growth Differ 2009; 51:743-52. [PMID: 19824899 DOI: 10.1111/j.1440-169x.2009.01133.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Akiko A Oohata
- Biological Laboratory, Kansai Medical University, 18-89 Uyamahigashimachi, Hirakata, Osaka, Japan.
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Proulx K, Cota D, Woods SC, Seeley RJ. Fatty acid synthase inhibitors modulate energy balance via mammalian target of rapamycin complex 1 signaling in the central nervous system. Diabetes 2008; 57:3231-8. [PMID: 18776140 PMCID: PMC2584128 DOI: 10.2337/db07-1690] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 09/01/2008] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Evidence links the hypothalamic fatty acid synthase (FAS) pathway to the regulation of food intake and body weight. This includes pharmacological inhibitors that potently reduce feeding and body weight. The mammalian target of rapamycin (mTOR) is an intracellular fuel sensor whose activity in the hypothalamus is also linked to the regulation of energy balance. The purpose of these experiments was to determine whether hypothalamic mTOR complex 1 (mTORC1) signaling is involved in mediating the effects of FAS inhibitors. RESEARCH DESIGN AND METHODS We measured the hypothalamic phosphorylation of two downstream targets of mTORC1, S6 kinase 1 (S6K1) and S6 ribosomal protein (S6), after administration of the FAS inhibitors C75 and cerulenin in rats. We evaluated food intake in response to FAS inhibitors in rats pretreated with the mTOR inhibitor rapamycin and in mice lacking functional S6K1 (S6K1(-/-)). Food intake and phosphorylation of S6K1 and S6 were also determined after C75 injection in rats maintained on a ketogenic diet. RESULTS C75 and cerulenin increased phosphorylation of S6K1 and S6, and their anorexic action was reduced in rapamycin-treated rats and in S6K1(-/-) mice. Consistent with our previous findings, C75 was ineffective at reducing caloric intake in ketotic rats. Under ketosis, C75 was also less efficient at stimulating mTORC1 signaling. CONCLUSIONS These findings collectively indicate an important interaction between the FAS and mTORC1 pathways in the central nervous system for regulating energy balance, possibly via modulation of neuronal glucose utilization.
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Affiliation(s)
- Karine Proulx
- From the Department of Psychiatry, University of Cincinnati, Genome Research Institute, Cincinnati, Ohio
| | - Daniela Cota
- From the Department of Psychiatry, University of Cincinnati, Genome Research Institute, Cincinnati, Ohio
| | - Stephen C. Woods
- From the Department of Psychiatry, University of Cincinnati, Genome Research Institute, Cincinnati, Ohio
| | - Randy J. Seeley
- From the Department of Psychiatry, University of Cincinnati, Genome Research Institute, Cincinnati, Ohio
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Ter Beek A, Keijser BJF, Boorsma A, Zakrzewska A, Orij R, Smits GJ, Brul S. Transcriptome analysis of sorbic acid-stressed Bacillus subtilis reveals a nutrient limitation response and indicates plasma membrane remodeling. J Bacteriol 2008; 190:1751-61. [PMID: 18156260 PMCID: PMC2258692 DOI: 10.1128/jb.01516-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Accepted: 12/13/2007] [Indexed: 11/20/2022] Open
Abstract
The weak organic acid sorbic acid is a commonly used food preservative, as it inhibits the growth of bacteria, yeasts, and molds. We have used genome-wide transcriptional profiling of Bacillus subtilis cells during mild sorbic acid stress to reveal the growth-inhibitory activity of this preservative and to identify potential resistance mechanisms. Our analysis demonstrated that sorbic acid-stressed cells induce responses normally seen upon nutrient limitation. This is indicated by the strong derepression of the CcpA, CodY, and Fur regulon and the induction of tricarboxylic acid cycle genes, SigL- and SigH-mediated genes, and the stringent response. Intriguingly, these conditions did not lead to the activation of sporulation, competence, or the general stress response. The fatty acid biosynthesis (fab) genes and BkdR-regulated genes are upregulated, which may indicate plasma membrane remodeling. This was further supported by the reduced sensitivity toward the fab inhibitor cerulenin upon sorbic acid stress. We are the first to present a comprehensive analysis of the transcriptional response of B. subtilis to sorbic acid stress.
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Affiliation(s)
- Alex Ter Beek
- Laboratory for Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
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Vazquez-Martin A, Ropero S, Brunet J, Colomer R, Menendez JA. Inhibition of Fatty Acid Synthase (FASN) synergistically enhances the efficacy of 5-fluorouracil in breast carcinoma cells. Oncol Rep 2007; 18:973-80. [PMID: 17786362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
The lipogenic enzyme fatty acid synthase (FASN) is differentially overexpressed and hyperactivated in a biologically aggressive subset of breast carcinomas and minimally in most normal adult tissues, rendering it an interesting target for anti-neoplastic therapy development. We previously reported that the FASN blockade can induce a synergistic chemosensitization of breast cancer cells to microtubule interfering agents (MIAs) such as docetaxel, paclitaxel and vinorelbine. Upon pharmacological inhibition of FASN activity using the natural antibiotic cerulenin [(2S,3R)-2,3-epoxy-4-oxo-7E,10E-dodecadienamide], we evaluated the role of FASN-catalyzed endogenous fatty acid biogenesis on the sensitivity of SK-Br3, MCF-7 and MDA-MB-231 breast cancer cell lines to the anti-metabolite 5-fluorouracil (5-FU). Cells were exposed simultaneously to cerulenin and 5-FU, sequentially to 5-FU followed by cerulenin or cerulenin followed by 5-FU. Cell viability was determined by MTT assays and the increase in 5-FU-induced cell growth inhibition was measured by dividing 5-FU IC30 and IC50 values (i.e., 30% and 50% inhibitory concentrations, respectively) that were obtained in the absence of cerulenin by those in its presence. Co-exposure to cerulenin enhanced 5-FU efficacy up to 20-, 81-, and 58-times in SK-Br3, MCF-7 and MDA-MB-231 cells, respectively. Pre-treatment with cerulenin followed by the addition of 5-FU increased 5-FU efficacy up to 31-, 87-, and 126-times in SK-Br3, MCF-7 and MDA-MB-231 cells, respectively. Pre-treatment with 5-FU followed by the addition of cerulenin augmented 5-FU efficacy up to 107-, 20-, and 18-times in SK-Br3, MCF-7 and MDA-MB-231 cells, respectively. When isobologram transformations of multiple dose-response analyses were performed to detect in vitro synergy, we concluded that the nature of the interaction between cerulenin and 5-FU in individual breast cancer cells lines generally exhibited sequence-dependency. Thus, while synergism was mainly observed when breast cancer cells were exposed to 5-FU prior to cerulenin, moderate synergism or additive interactions was obtained either when the chemical FASN blocker preceded 5-FU or when both drugs were concurrently administered. Of note, no antagonist interactions occurred upon any schedule of combined treatment with cerulenin and 5-FU. Our current findings revealing a schedule-dependent synergistic interaction between 5-FU and cerulenin represents, to the best of our knowledge, the first evidence that FASN-catalyzed de novo FA biogenesis plays a key role in regulating breast cancer cell response to antimetabolite-based therapies.
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Affiliation(s)
- Alejando Vazquez-Martin
- Catalan Institute of Oncology-Health Services Division of Catalonia, 17007 Girona, Catalonia, Spain
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Ho TS, Ho YP, Wong WY, Chi-Ming Chiu L, Wong YS, Eng-Choon Ooi V. Fatty acid synthase inhibitors cerulenin and C75 retard growth and induce caspase-dependent apoptosis in human melanoma A-375 cells. Biomed Pharmacother 2007; 61:578-87. [PMID: 17904792 DOI: 10.1016/j.biopha.2007.08.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Fatty acid synthase (FAS) has been shown previously to be highly expressed in breast and prostate carcinomas, but has low expression level in normal tissues. We also found in this study that FAS was expressed in a number of cancer cell lines of different histotypes. The growth-inhibitory effects of FAS inhibitors cerulenin and C75 were then investigated on these cancer cell lines, particularly the human melanoma A-375. MTT assay revealed that the cancer cell proliferation and viability was reduced dose- and time-dependently by 20.8%-87.1% of the control levels after 24 and 48 h of treatment with 20-160 microM of the inhibitor. Immunoblotting studies showed that both cerulenin and C75 induced poly(ADP-ribose) polymerase (PARP) cleavage in the melanoma cells dose-dependently. Procaspase-3 was also found to be processed into the active and smaller 17 and 19 kDa subunits, and administration of pan-caspase inhibitor Z-VAD-FMK completely rescued the cells from PARP cleavage. This indicated that the cerulenin- and C75-induced apoptosis involved caspase activation. The proapoptotic effects of the FAS inhibitors were further confirmed using confocal microscopy with annexin-V FITC and propidium iodide staining. DNA flow cytometric studies demonstrated that the FAS inhibitors accumulated G2/M cells preceding the elevation of sub G1 or apoptotic cells with fragmented DNA. The induced cell cycle arrest and apoptosis were associated with elevation of p21 and depletion of Bcl-xL and Mcl-1, respectively. Results from this study suggest that FAS inhibitors retard growth of melanoma A-375 cells, involving activation of caspase-dependent apoptosis.
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Affiliation(s)
- Tik-Shun Ho
- Department of Biology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR
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Abstract
We report the presence of a new fatty acyl coenzyme A (acyl-CoA) elongation system in Cryptosporidium and the functional characterization of the key enzyme, a single long-chain fatty acid elongase (LCE), in this parasite. This enzyme contains conserved motifs and predicted transmembrane domains characteristic to the elongase family and is placed within the ELO6 family specific for saturated substrates. CpLCE1 gene transcripts are present at all life cycle stages, but the levels are highest in free sporozoites and in stages at 36 h and 60 h postinfection that typically contain free merozoites. Immunostaining revealed localization to the outer surface of sporozoites and to the parasitophorous vacuolar membrane. Recombinant CpLCE1 displayed allosteric kinetics towards malonyl-CoA and palmitoyl-CoA and Michaelis-Menten kinetics towards NADPH. Myristoyl-CoA (C14:0) and palmitoyl-CoA (C16:0) display the highest activity when used as substrates, and only one round of elongation occurs. CpLCE1 is fairly resistant to cerulenin, an inhibitor for both type I and II fatty acid synthases (i.e., maximum inhibitions of 20.5% and 32.7% were observed when C16:0 and C14:0 were used as substrates, respectively). These observations ultimately validate the function of CpLCE1.
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Affiliation(s)
- Jason M Fritzler
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, 4467 TAMU, College Station, TX 77843-4467, USA
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Chayakulkeeree M, Rude TH, Toffaletti DL, Perfect JR. Fatty acid synthesis is essential for survival of Cryptococcus neoformans and a potential fungicidal target. Antimicrob Agents Chemother 2007; 51:3537-45. [PMID: 17698629 PMCID: PMC2043279 DOI: 10.1128/aac.00442-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Fatty acid synthase in the yeast Cryptococcus neoformans is composed of two subunits encoded by FAS1 and FAS2 genes. We inserted a copper-regulated promoter (P(CTR4-2)) to regulate FAS1 and FAS2 expression in Cryptococcus neoformans (strains P(CTR4-2)/FAS1 and P(CTR4-2)/FAS2, respectively). Both mutants showed growth rates similar to those of the wild type in a low-copper medium in which FAS1 and FAS2 were expressed, but even in the presence of exogenous fatty acids, strains were suppressed in growth under high-copper conditions. The treatment of C. neoformans with fluconazole was shown to have an increased inhibitory activity and even became fungicidal when either FAS1 or FAS2 expression was suppressed. Furthermore, a subinhibitory dose of fluconazole showed anticryptococcal activity in vitro in the presence of cerulenin, a fatty acid synthase inhibitor. In a murine model of pulmonary cryptococcosis, a tissue census of yeast cells in P(CTR4-2)/FAS2 strain at day 7 of infection was significantly lower than that in mice treated with tetrathiomolybdate, a copper chelator (P < 0.05), and a yeast census of P(CTR4-2)/FAS1 strain at day 14 of infection in the brain was lower in the presence of more copper. In fact, no positive cultures from the brain were detected in mice (with or without tetrathiomolybdate treatment) infected with the P(CTR4-2)/FAS2 strain, which implies that this mutant did not reach the brain in mice. We conclude that both FAS1 and FAS2 in C. neoformans are essential for in vitro and in vivo growth in conditions with and without exogenous fatty acids and that FAS1 and FAS2 can potentially be fungicidal targets for C. neoformans with a potential for synergistic behavior with azoles.
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Affiliation(s)
- Methee Chayakulkeeree
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA
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Kadokawa H, Aikawa K, Kimura K, Blache D, Williams IH, Martin GB. Links between de novo fatty acid synthesis and leptin secretion in bovine adipocytes. J Vet Med Sci 2007; 69:225-31. [PMID: 17409636 DOI: 10.1292/jvms.69.225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Leptin secretion by adipose tissue is involved in many physiological control systems, including those that determine growth, development, body composition, milk production, and reproductive function. In the adipocyte of monogastric animals, malonyl CoA (coenzyme A) seems to link the flux of energy substrates to the control of leptin production. In this study, we tested this for ruminants by examining the effect of cerulenin, an inhibitor of de novo fatty acid synthesis at the step from malonyl CoA to palmitate, on leptin production by cultured bovine adipocytes derived from intermuscular fat. Purified preadipocytes were obtained by the ceiling culture method, and adipogenic media were used to induce their differentiation into adipocytes. We found that leptin concentrations increased significantly with time in culture, and with increases in glucose concentration. Addition of 2-deoxy-D-glucose to the medium, a competitive inhibitor of glucose transport and metabolism, suppressed leptin secretion. In media with high glucose concentrations, cerulenin enhanced leptin secretion. We conclude that, as in monogastrics, malonyl CoA may play a key role in the control of leptin secretion in ruminants.
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Affiliation(s)
- Hiroya Kadokawa
- Department of Veterinary Medicine, Faculty of Agricultural Science, University of Yamaguchi, Japan
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Rassmann A, Henke A, Jarasch N, Lottspeich F, Saluz HP, Munder T. The human fatty acid synthase: a new therapeutic target for coxsackievirus B3-induced diseases? Antiviral Res 2007; 76:150-8. [PMID: 17662476 DOI: 10.1016/j.antiviral.2007.06.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 06/11/2007] [Accepted: 06/21/2007] [Indexed: 11/30/2022]
Abstract
Coxsackievirus is linked to a large variety of severe human and animal diseases such as myocarditis. The interplay between host factors and virus components is crucial for the fate of the infected cells. However, host proteins which may play a role in coxsackievirus-induced diseases are ill-defined. Two-dimensional gel electrophoresis of protein extracts obtained from coxsackievirus B3 (CVB3)-infected and uninfected HeLa or HepG2 cells combined with spot analysis revealed several proteins which are exclusively up-regulated in infected cells. One of these proteins was identified as the fatty acid synthase (FAS). By using cerulenin and C75, two known inhibitors of FAS we were able to significantly block CVB3 replication. FAS appears to be directly involved in CVB3-caused pathology and is therefore suitable as a therapeutic target in CVB3-induced diseases.
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Affiliation(s)
- Alexander Rassmann
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Department of Cell and Molecular Biology, Beutenbergstrasse 11a, D-07745 Jena, Germany
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Sharma S, Sharma SK, Modak R, Karmodiya K, Surolia N, Surolia A. Mass spectrometry-based systems approach for identification of inhibitors of Plasmodium falciparum fatty acid synthase. Antimicrob Agents Chemother 2007; 51:2552-8. [PMID: 17485508 PMCID: PMC1913259 DOI: 10.1128/aac.00124-07] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence of strains of Plasmodium falciparum resistant to the commonly used antimalarials warrants the development of new antimalarial agents. The discovery of type II fatty acid synthase (FAS) in Plasmodium distinct from the FAS in its human host (type I FAS) opened up new avenues for the development of novel antimalarials. The process of fatty acid synthesis takes place by iterative elongation of butyryl-acyl carrier protein (butyryl-ACP) by two carbon units, with the successive action of four enzymes constituting the elongation module of FAS until the desired acyl length is obtained. The study of the fatty acid synthesis machinery of the parasite inside the red blood cell culture has always been a challenging task. Here, we report the in vitro reconstitution of the elongation module of the FAS of malaria parasite involving all four enzymes, FabB/F (beta-ketoacyl-ACP synthase), FabG (beta-ketoacyl-ACP reductase), FabZ (beta-ketoacyl-ACP dehydratase), and FabI (enoyl-ACP reductase), and its analysis by matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF MS). That this in vitro systems approach completely mimics the in vivo machinery is confirmed by the distribution of acyl products. Using known inhibitors of the enzymes of the elongation module, cerulenin, triclosan, NAS-21/91, and (-)-catechin gallate, we demonstrate that accumulation of intermediates resulting from the inhibition of any of the enzymes can be unambiguously followed by MALDI-TOF MS. Thus, this work not only offers a powerful tool for easier and faster throughput screening of inhibitors but also allows for the study of the biochemical properties of the FAS pathway of the malaria parasite.
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Affiliation(s)
- Shilpi Sharma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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Zhao Y, Sharp GWG, Straub SG. The inhibitors of protein acylation, cerulenin and tunicamycin, increase voltage-dependent Ca(2+) currents in the insulin-secreting INS 832/13 cell. Biochem Pharmacol 2007; 74:273-80. [PMID: 17548064 PMCID: PMC2065765 DOI: 10.1016/j.bcp.2007.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2006] [Revised: 03/23/2007] [Accepted: 04/06/2007] [Indexed: 11/23/2022]
Abstract
As it has been suggested that protein acylation plays a role in nutrient stimulus-secretion coupling in the pancreatic beta-cell, we examined the insulin-secreting INS 832/13 beta-cell line for evidence that protein acylation was involved. The perforated whole-cell configuration was employed to voltage-clamp INS 832/13 cells. Voltage pulses were applied and Ca(2+) currents measured in the presence and absence of the protein acylation inhibitors cerulenin and tunicamycin. Both inhibitors enhanced the peak amplitude of I(Ca,L). Both increased the peak inward current in the range between -40 and +30mV and shifted the apparent maximum current by 10mV in the hyperpolarizing direction without affecting the activation threshold of -40mV. The two drugs had qualitatively and quantitatively similar effects. Steady-state activation curves revealed that cerulenin and tunicamycin shifted the activation curves in the hyperpolarization direction. Activation time constants were significantly reduced in the presence of both drugs. The Ca(2+) charge influx was increased by the drugs at all potentials tested. In contrast to these effects on the L-type Ca(2+) channel, the two inhibitors of protein acylation had no effect on the ATP-sensitive K(+) channel. The results suggest that protein acylation exerts a tonic inhibitory effect on L-type Ca(2+) channel function in the insulin-secreting beta-cell.
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Affiliation(s)
- Ying Zhao
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401 USA
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Wang WQ, Zhao XY, Gong XB, Zhang XH. [Cerulenin changes apoptosis related genes expression in multiple myeloma cell line U266]. Zhonghua Xue Ye Xue Za Zhi 2007; 28:239-42. [PMID: 17877200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
OBJECTIVE To study the expression changes of apoptosis related genes induced by cerulenin in multiple myeloma cell line U266 and explore its molecular mechanism. METHODS The expression changes of 96 apoptosis related genes were analyzed by superArray cDNA in U266 cells treated with cerulenin (20 microg/ml) for 12 h. Semi-quantitative RT-PCR was used to confirm the representative expression changes genes, Rip2, caspase 9 and TRAF2. RESULTS After treated with cerulenin for 12 h, 44 apoptosis related genes expression in the U266 cells were changed, among which 41 were over 2 fold increase and 3 over 2 fold decrease. The expression of caspase 9 was increased markedly, indicating that mitochondria pathway played a key role in cerulenin inducing apoptosis and TRAF2 expression change suggested that nuclear factor (NF) participates in cerulenin inducing apoptosis. CONCLUSION The death acceptor signaling pathway and the death acceptor non-dependence signaling pathway co-regulate cerulenin inducing apoptosis in U266 cells. Mitochondria pathway played the key role and nuclear factor (NF) participates in the apoptosis process.
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Affiliation(s)
- Wei-Qin Wang
- The Hematology Department, Second Affiliated Hospital of Medical School, Zhejiang University, Hangzhou 310009, China
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Abstract
The number of ion channels expressed on the cell surface shapes the complex electrical response of excitable cells. An imbalance in the ratio of inward and outward conducting channels is unfavorable and often detrimental. For example, over- or underexpression of voltage-gated K(+) (Kv) channels can be cytotoxic and in some cases lead to disease. In this study, we demonstrated a novel role for S-acylation in Kv1.5 cell surface expression. In transfected fibroblasts, biochemical evidence showed that Kv1.5 is posttranslationally modified on both the NH(2) and COOH termini via hydroxylamine-sensitive thioester bonds. Pharmacological inhibition of S-acylation, but not myristoylation, significantly decreased Kv1.5 expression and resulted in accumulation of channel protein in intracellular compartments and targeting for degradation. Channel protein degradation was rescued by treatment with proteasome inhibitors. Time course experiments revealed that S-acylation occurred in the biosynthetic pathway of nascent channel protein and showed that newly synthesized Kv1.5 protein, but not protein expressed on the cell surface, is sensitive to inhibitors of thioacylation. Sensitivity to inhibitors of S-acylation was governed by COOH-terminal, but not NH(2)-terminal, cysteines. Surprisingly, although intracellular cysteines were required for S-acylation, mutation of these residues resulted in an increase in Kv1.5 cell surface channel expression, suggesting that screening of free cysteines by fatty acylation is an important regulatory step in the quality control pathway. Together, these results show that S-acylation can regulate steady-state expression of Kv1.5.
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Affiliation(s)
- Lian Zhang
- Dept. of Pharmacology, University of Michigan, 1150 W. Medical Center Dr., 1301 MSRB III, Ann Arbor, MI 48109-0632, USA
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Weber RWS, Kappe R, Paululat T, Mösker E, Anke H. Anti-Candida metabolites from endophytic fungi. Phytochemistry 2007; 68:886-92. [PMID: 17286994 DOI: 10.1016/j.phytochem.2006.12.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 12/19/2006] [Accepted: 12/20/2006] [Indexed: 05/13/2023]
Abstract
Submerged cultures of some 1500 Ascomycota and Basidiomycota isolated from their fruit-bodies or as soil-borne, coprophilous or endophytic fungi were screened for activity against Candida albicans and a range of other pathogenic and saprotrophic fungi. Considerably more Ascomycota (11-16%) than Basidiomycota (3.5%) produced metabolites with activity against C. albicans. From five species of endophytes, six bioactive compounds were isolated and identified, viz. cerulenin (1), arundifungin (2), sphaeropsidin A (3), 5-(1,3-butadiene-1-yl)-3-(propene-1-yl)-2-(5H)-furanone (4), ascosteroside A (formerly called ascosteroside; 5) and a derivative of 5, ascosteroside B (6). 1, 3 and 5 were isolated from fungi belonging to different orders than previously described producers. Antifungal activities of 2 and 4-6 in the agar diffusion test were comparable with those of amphotericin B. Compound 6 exhibited a similar antifungal activity as 5 but its cytotoxicity towards Hep G2 cells was considerably lower. This study points to endophytic fungi related to hemibiotrophic or latent plant pathogens as an important source of bio- and chemodiversity.
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Affiliation(s)
- Roland W S Weber
- Department of Biotechnology, University of Kaiserslautern, Erwin-Schrödinger-Strasse 56, D-67663 Kaiserslautern, Germany
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Abstract
BACKGROUND Cerulenin, an inhibitor of protein acylation, has been used as a tool to study the potential role of protein acylation in a variety of activities in different cells, and in stimulus-secretion coupling in pancreatic islets and clonal beta-cells. METHODS In the present study we investigated its effects on stimulated insulin secretion, glucose metabolism and utilization, oxygen consumption and ATP levels. RESULTS In isolated rat pancreatic islets, cerulenin pre-treatment (100 microM) inhibited insulin secretion in response to glucose, and to the non-hydrolysable analogue of leucine, aminobicyclo-[2,2,1]heptane-2-carboxylic acid (BCH). These data are in accord with the hypothesis that protein acylation could be involved in the stimulation of insulin secretion. However, we also found that cerulenin profoundly decreased glucose oxidation, glucose utilization, oxygen consumption and ATP levels. Consequently, decreased metabolism provides an alternative mechanism to inhibition of protein acylation that could explain the inhibition of insulin secretion by cerulenin. CONCLUSIONS Inhibition of insulin secretion by cerulenin can no longer be taken as evidence in favour of a role for protein acylation in the control of insulin release. As protein acylation is known to be involved in the normal functioning of proteins in stimulus-secretion coupling and exocytosis, more direct approaches to understand its role(s) are required.
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Affiliation(s)
- Susanne G Straub
- The Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
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Abstract
Emerging evidence suggests a potential role of stearoyl-CoA desaturase (SCD)-1 in the control of body weight and energy homeostasis. The present study was conducted to investigate the effects of several energy balance-related factors (leptin, cerulenin, food deprivation, genotype, and gender) on SCD gene expression in chickens. In experiment 1, 6-week-old female and male broiler chickens were used. In experiment 2, two groups of 3-week-old broiler chickens were continuously infused with recombinant chicken leptin (8 micro g/kg/h) or vehicle for 6 h. In experiment 3, two groups of 2-week-old broiler chickens received i.v. injections of cerulenin (15 mg/kg) or vehicle. In experiment 4, two broiler chicken lines (fat and lean) were submitted to two nutritional states (food deprivation for 16 or 24 h and feeding ad libitum). At the end of each experiment, tissues were collected for analyzing SCD gene expression. Data from experiment 1 showed that SCD is ubiquitously expressed in chicken tissues with highest levels in the proventriculus followed by the ovary, hypothalamus, kidney, liver, and adipose tissue in female, and hypothalamus, leg muscle, pancreas, liver, and adipose tissue in male. Female chickens exhibited significantly higher SCD mRNA levels in kidney, breast muscle, proventriculus, and intestine than male chickens. However, hypothalamic SCD gene expression was higher in male than in female (P < 0.05). Leptin increased SCD gene expression in chicken liver (P < 0.05), whereas cerulenin decreased SCD mRNA levels in muscle. Both leptin and cerulenin significantly reduced food intake (P < 0.05). Food deprivation for either 16 or 24 h decreased the hepatic SCD gene expression in fat line and lean line chickens compared with their fed counterparts (P < 0.05). The hypothalamic SCD mRNA levels were decreased in both lines only after 24 h of food deprivation (P < 0.05). In conclusion, SCD is ubiquitously expressed in chickens and it is regulated by leptin, cerulenin, nutritional state, and gender in a tissue-specific manner.
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Affiliation(s)
- Sami Dridi
- Laboratory of Physiology, Immunology, and Genetics of Domestic Animals, Catholic University of Leuven, KU Leuven, 3001 Heverlee, Belgium.
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Ramya TNC, Mishra S, Karmodiya K, Surolia N, Surolia A. Inhibitors of nonhousekeeping functions of the apicoplast defy delayed death in Plasmodium falciparum. Antimicrob Agents Chemother 2006; 51:307-16. [PMID: 17060533 PMCID: PMC1797641 DOI: 10.1128/aac.00808-06] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Targeting of apicoplast replication and protein synthesis in the apicomplexan Toxoplasma gondii has conventionally been associated with the typical "delayed death" phenotype, characterized by the death of parasites only in the generation following drug intervention. We demonstrate that antibiotics like clindamycin, chloramphenicol, and tetracycline, inhibitors of prokaryotic protein synthesis, invoke the delayed death phenotype in Plasmodium falciparum, too, as evident from a specific reduction of apicoplast genome copy number. Interestingly, however, molecules like triclosan, cerulenin, fops, and NAS-91, inhibitors of the recently discovered fatty acid synthesis pathway, and succinyl acetone, an inhibitor of heme biosynthesis that operates in the apicoplast of the parasite, display rapid and striking parasiticidal effects. Our results draw a clear distinction between apicoplast functions per se and the apicoplast as the site of metabolic pathways, which are required for parasite survival, and thus subserve the development of novel antimalarial therapy.
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Affiliation(s)
- T N C Ramya
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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42
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Wang WQ, Zhao XY, Xu GB, Liang Y. [Study on proliferation inhibiting and apoptosis inducing effects of cerulenin on multiple myeloma cells]. Zhonghua Xue Ye Xue Za Zhi 2006; 27:675-7. [PMID: 17343199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
OBJECTIVE To determine whether fatty acid synthase (FAS) is expressed in human multiple myeloma( MM) cells and investigate the proliferation inhibition effect of fatty acid synthase inhibitor cerulenin on multiple myeloma cell line U266 and its mechanism. METHODS FAS mRNA expression in human MM cell line U266, RPMI8226 cell was assayed by RT-PCR. The proliferation inhibition rate of U266 cells was assayed by MTr analysis. Cell apoptosis and cycle distribution were evaluated by flow cytometry (FCM). RESULTS FAS mRNA was highly expressed in human multiple myeloma cell lines as compared with healthy donor PBMNCs. After U266 cells were treated with cerulenin (the concentrations from 5 microg/ml to 640 microg/ ml) for 24 h, the cell proliferation was markedly inhibited with a dose related manner, while the inhibition rate of human skin fibroblast cells were all lower than 30%. When U266 cells were treated with 20 pjg/ml cerulenin for 12 h and 24 h, the early apoptosis rate revealed by Annexin V/PI were 56. 9% and 69. 3% respectively, being higher than that of the blank controls (4. 3% and 1.8%, P < 0. 01). Cell cycle analysis showed it was blocked in S phase. Conclusion FAS is highly expressed in human MM. Cerulenin could induce apoptosis and inhibit proliferation of U266 cells. FAS might be a new potential target for multiple myeloma treatment.
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Affiliation(s)
- Wei-qin Wang
- The Second Affiliated Hospital of Medical School, Zhejiang University, Hangzhou 310009, China
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Abstract
High levels of fatty acid synthase (FAS) expression have been observed in several cancers, including breast, prostate, colon and lung carcinoma, compared with their respective normal tissue. We present data that show high levels of FAS protein in human and rat glioma cell lines and human glioma tissue samples, as compared to normal rat astrocytes and normal human brain. Incubating glioma cells with the FAS inhibitor cerulenin decreased endogenous fatty acid synthesis by approximately 50%. Cell cycle analysis demonstrated a time- and dose-dependent increase in S-phase cell arrest following cerulenin treatment for 24 h. Further, treatment with cerulenin resulted in time- and dose-dependent decreases in glioma cell viability, as well as reduced clonogenic survival. Increased apoptotic cell death and PARP cleavage were observed in U251 and SNB-19 cells treated with cerulenin, which was independent of the death receptor pathway. Overexpressing Bcl-2 inhibited cerulenin-mediated cell death. In contrast, primary rat astrocytes appeared unaffected. Finally, RNAi-mediated knockdown of FAS leading to reduced FAS enzymatic activity was associated with decreased glioma cell viability. These findings suggest that FAS might be a novel target for antiglioma therapy.
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Affiliation(s)
- W Zhao
- Department of Radiation Oncology, Brain Tumor Center of Excellence, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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Pleite R, Martínez-Force E, Garcés R. Inhibitors of fatty acid biosynthesis in sunflower seeds. J Plant Physiol 2006; 163:885-94. [PMID: 16500723 DOI: 10.1016/j.jplph.2005.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Accepted: 11/05/2005] [Indexed: 05/06/2023]
Abstract
During de novo fatty acid synthesis in sunflower seeds, saturated fatty acid production is influenced by the competition between the enzymes of the principal pathways and the saturated acyl-ACP thioesterases. Genetic backgrounds with more efficient saturated acyl-ACP thioesterase alleles only express their phenotypic effects when the alleles for the enzymes in the main pathway are less efficient. For this reason, we studied the incorporation of [2-(14)C]acetate into the lipids of developing sunflower seeds (Helianthus annuus L.) from several mutant lines in vivo. The labelling of different triacylglycerol fatty acids in different oilseed mutants reflects the fatty acid composition of the seed and supports the channelling theory of fatty acid biosynthesis. Incubation with methyl viologen diminished the conversion of stearoyl-ACP to oleoyl-ACP in vivo through a decrease in the available reductant power. In turn, this led to the accumulation of stearoyl-ACP to the levels detected in seeds from high stearic acid mutants. The concomitant reduction of oleoyl-ACP content inside the plastid allowed us to study the activity of acyl-ACP thioesterases on saturated fatty acids. In these mutants, we verified that the accumulation of saturated fatty acids requires efficient thioesterase activity on saturated-ACPs. By studying the effects of cerulenin on the in vivo incorporation of [2-(14)C]acetate into lipids and on the in vitro activity of beta-ketoacyl-ACP synthase II, we found that elongation to very long chain fatty acids can occur both inside and outside of the plastid in sunflower seeds.
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Affiliation(s)
- Rafael Pleite
- Instituto de la Grasa, CSIC, Av Padre García Tejero 4, Sevilla, Spain
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Chung KS, Sun NK, Lee SH, Lee HJ, Choi SJ, Kim SK, Song JH, Jang YJ, Song KB, Yoo HS, Simon J, Won M. Cerulenin-mediated apoptosis is involved in adenine metabolic pathway. Biochem Biophys Res Commun 2006; 349:1025-31. [PMID: 16962997 DOI: 10.1016/j.bbrc.2006.08.130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Accepted: 08/22/2006] [Indexed: 11/27/2022]
Abstract
Cerulenin, a fatty acid synthase (FAS) inhibitor, induces apoptosis of variety of tumor cells. To elucidate mode of action by cerulenin, we employed the proteomics approach using Schizosaccharomyces pombe. The differential protein expression profile of S. pombe revealed that cerulenin modulated the expressions of proteins involved in stresses and metabolism, including both ade10 and adk1 proteins. The nutrient supplementation assay demonstrated that cerulenin affected enzymatic steps transferring a phosphoribosyl group. This result suggests that cerulenin accumulates AMP and p-ribosyl-s-amino-imidazole carboxamide (AICAR) and reduces other necessary nucleotides, which induces feedback inhibition of enzymes and the transcriptional regulation of related genes in de novo and salvage adenine metabolic pathway. Furthermore, the deregulation of adenine nucleotide synthesis may interfere ribonucleotide reductase and cause defects in cell cycle progression and chromosome segregation. In conclusion, cerulenin induces apoptosis through deregulation of adenine nucleotide biosynthesis resulting in nuclear division defects in S. pombe.
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Affiliation(s)
- Kyung-Sook Chung
- Biopharmaceutical Division, KRIBB, 52 Oun-dong, Yusong-gu, Daejeon 305-806, Republic of Korea
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García D, Mañas P, Gómez N, Raso J, Pagán R. Biosynthetic requirements for the repair of sublethal membrane damage in Escherichia coli cells after pulsed electric fields. J Appl Microbiol 2006; 100:428-35. [PMID: 16478482 DOI: 10.1111/j.1365-2672.2005.02795.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS The aim was to evaluate the biosynthetic requirements for the repair of sublethal membrane damages in Escherichia coli cells after exposure to pulsed electric fields (PEF). METHODS AND RESULTS The partial loss of the barrier and homeostatic functions of the cytoplasmic membrane was examined by adding sodium chloride to the recovery media. More than 4 log10 cycles of survivors were sublethally injured after PEF. Repair of such sublethal membrane damages occurred when survivors to PEF were incubated in peptone water for 2 h. Two different types of sublethally injured cells were detected. Whereas a small proportion (<5%) repaired after PEF in less than 2 min, the repair of the remaining 95% injured cells lasted 2 h and was dependent on biosynthetic requirements. The addition of inhibitors such as chloramphenicol, cerulenin, penicillin G, rifampicin and sodium azide to the liquid repair medium showed that the repair required energy and lipid synthesis, and was not dependent on protein, peptidoglican or RNA synthesis. CONCLUSIONS Cell survival after PEF is dependent on the repair of the cytoplasmic membrane. Requirement of lipid synthesis for the repair of sublethally injured cells confirms that the cytoplasmic membrane is a target directly involved in the mechanism of inactivation by PEF. SIGNIFICANCE AND IMPACT OF THE STUDY Knowledge about the damages inflicted by PEF might help in the design of more efficient treatments.
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Affiliation(s)
- D García
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain
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Dridi S, Ververken C, Hillgartner FB, Arckens L, Lutgarde A, Van der Gucht E, Cnops L, Decuypere E, Buyse J. FAS inhibitor cerulenin reduces food intake and melanocortin receptor gene expression without modulating the other (an)orexigenic neuropeptides in chickens. Am J Physiol Regul Integr Comp Physiol 2006; 291:R138-47. [PMID: 16455759 DOI: 10.1152/ajpregu.00899.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cerulenin, a natural fatty acid synthase (FAS) inhibitor, and its synthetic analog C75 are hypothesized to alter the metabolism of neurons in the hypothalamus that regulate ingestive behavior to cause a profound decrease of food intake and an increase in metabolic rate, leading to body weight loss. The bulk of data exclusively originates from mammals (rodents); however, such effects are currently lacking in nonmammalian species. We have, therefore, addressed this issue in broiler chickens because this species is selected for high growth rate and high food intake and is prone to obesity. First, we demonstrate that FAS messenger and protein are expressed in the hypothalamus of chickens. FAS immunoreactivity was detected in a number of brain regions, including the nucleus paraventricularis magnocellularis and the nucleus infundibuli hypothalami, the avian equivalent of the mammalian arcuate nucleus, suggesting that FAS may be involved in the regulation of food intake. Second, we show that hypothalamic FAS gene expression was significantly (P < 0.05) decreased by overnight fasting similar to that in liver, indicating that hypothalamic FAS gene is regulated by energy status in chickens. Finally, to investigate the physiological consequences of in vivo inhibition of fatty acid synthesis on food intake, we administered cerulenin by intravenous injections (15 mg/kg) to 2-wk-old broiler chickens. Cerulenin administration significantly reduced food intake by 23 to 34% (P < 0.05 to P < 0.0001) and downregulated FAS and melanocortin receptors 1, 4, and 5 gene expression (P < 0.05). However, the known orexigenic (neuropeptide Y, agouti gene-related peptide, orexin, and orexin receptor) and anorexigenic (pro-opiomelanocortin and corticotropin-releasing hormone) neuropeptide mRNA levels remained unchanged after cerulenin treatment. These results suggest that the catabolic effect of cerulenin in chickens may be mediated through the melanocortin system rather than the other neuropeptides known to be involved in food intake regulation.
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Affiliation(s)
- Sami Dridi
- Laboratory of Physiology and Immunology of Domestic Animals, Catholic University of Leuven, Heverlee, Belgium.
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Adhikari RP, Novick RP. Subinhibitory cerulenin inhibits staphylococcal exoprotein production by blocking transcription rather than by blocking secretion. Microbiology (Reading) 2005; 151:3059-3069. [PMID: 16151216 DOI: 10.1099/mic.0.28102-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cerulenin is an antibiotic that inhibits fatty acid synthesis by covalent modification of the active thiol of the chain-elongation subtypes of beta-ketoacyl-acyl carrier protein synthase. It also inhibits other processes that utilize essential thiols. Cerulenin has been widely reported to block protein secretion at sub-MIC levels, an effect that has been postulated to represent interference with membrane function through interference with normal fatty acid synthesis. This study confirms the profound reduction in extracellular proteins caused by low concentrations of the antibiotic, and shows by Northern blot hybridization that this reduction is due to interference with transcription. By exchanging promoters between entB, a gene that is inhibited by cerulenin, and entA, a gene that is not, it was also shown that the antibiotic does not block secretion. Subinhibitory concentrations of cerulenin were also found to block transcriptional activation of at least two regulatory determinants, agr and sae, that function by signal transduction. Interference with the activation of these and other regulatory determinants probably accounts for much of the inhibitory effect on exoprotein production of sub-MIC concentrations of cerulenin.
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Affiliation(s)
- Rajan P Adhikari
- Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine and Department of Microbiology, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA
| | - Richard P Novick
- Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine and Department of Microbiology, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA
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Abstract
The activation of cell cycle regulators at the G1/S boundary has been linked to the cellular protein synthesis rate. It is conceivable that regulatory mechanisms are required to allow cells to coordinate the synthesis of other macromolecules with cell cycle progression. The availability of highly synchronized cells and flow cytometric methods facilitates investigation of the dynamics of lipid synthesis in the entire cell cycle of the heterotrophic dinoflagellate Crypthecodinium cohnii. Flow cytograms of Nile red-stained cells revealed a stepwise increase in the polar lipid content and a continuous increase in neutral lipid content in the dinoflagellate cell cycle. A cell cycle delay at early G1, but not G2/M, was observed upon inhibition of lipid synthesis. However, lipid synthesis continued during cell cycle arrest at the G1/S transition. A cell cycle delay was not observed when inhibitors of cellulose synthesis and fatty acid synthesis were added after the late G1 phase of the cell cycle. This implicates a commitment point that monitors the synthesis of fatty acids at the late G1 phase of the dinoflagellate cell cycle. Reduction of the glucose concentration in the medium down-regulated the G1 cell size with a concomitant forward shift of the commitment point. Inhibition of lipid synthesis up-regulated cellulose synthesis and resulted in an increase in cellulosic contents, while an inhibition of cellulose synthesis had no effects on lipid synthesis. Fatty acid synthesis and cellulose synthesis are apparently coupled to the cell cycle via independent pathways.
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Affiliation(s)
- Alvin C M Kwok
- Department of Biology, Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong SAR, PR China
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Koo AJK, Fulda M, Browse J, Ohlrogge JB. Identification of a plastid acyl-acyl carrier protein synthetase in Arabidopsis and its role in the activation and elongation of exogenous fatty acids. Plant J 2005; 44:620-32. [PMID: 16262711 DOI: 10.1111/j.1365-313x.2005.02553.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Plant cells are known to elongate exogenously provided fatty acid (FA), but the subcellular sites and mechanisms for this process are not currently understood. When Arabidopsis leaves were incubated with 14C-FAs with or=20 carbons) but not synthesis of 14C-unsaturated 18-carbon or 16-carbon FAs. Isolated pea chloroplasts were also able to elongate 14C-FAs (
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Affiliation(s)
- Abraham J K Koo
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
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