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Nandi I, Ji L, Smith HW, Avizonis D, Papavasiliou V, Lavoie C, Pacis A, Attalla S, Sanguin-Gendreau V, Muller WJ. Targeting fatty acid oxidation enhances response to HER2-targeted therapy. Nat Commun 2024; 15:6587. [PMID: 39097623 PMCID: PMC11297952 DOI: 10.1038/s41467-024-50998-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 07/23/2024] [Indexed: 08/05/2024] Open
Abstract
Metabolic reprogramming, a hallmark of tumorigenesis, involves alterations in glucose and fatty acid metabolism. Here, we investigate the role of Carnitine palmitoyl transferase 1a (Cpt1a), a key enzyme in long-chain fatty acid (LCFA) oxidation, in ErbB2-driven breast cancers. In ErbB2+ breast cancer models, ablation of Cpt1a delays tumor onset, growth, and metastasis. However, Cpt1a-deficient cells exhibit increased glucose dependency that enables survival and eventual tumor progression. Consequently, these cells exhibit heightened oxidative stress and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Inhibiting Nrf2 or silencing its expression reduces proliferation and glucose consumption in Cpt1a-deficient cells. Combining the ketogenic diet, composed of LCFAs, or an anti-ErbB2 monoclonal antibody (mAb) with Cpt1a deficiency significantly perturbs tumor growth, enhances apoptosis, and reduces lung metastasis. Using an immunocompetent model, we show that Cpt1a inhibition promotes an antitumor immune microenvironment, thereby enhancing the efficacy of anti-ErbB2 mAbs. Our findings underscore the importance of targeting fatty acid oxidation alongside HER2-targeted therapies to combat resistance in HER2+ breast cancer patients.
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Affiliation(s)
- Ipshita Nandi
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Linjia Ji
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
| | - Harvey W Smith
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
| | - Daina Avizonis
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
| | - Vasilios Papavasiliou
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Cynthia Lavoie
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
| | - Alain Pacis
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
- Canadian Centre for Computational Genomics, McGill University, Montreal, QC, Canada
| | - Sherif Attalla
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Virginie Sanguin-Gendreau
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada
- Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - William J Muller
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, QC, Canada.
- Department of Biochemistry, McGill University, Montreal, QC, Canada.
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Zhao H, Wu T, Luo Z, Huang Q, Zhu S, Li C, Zhang Z, Zhang J, Zeng J, Zhang Y. Construction and validation of a fatty acid metabolism-related gene signature for predicting prognosis and therapeutic response in patients with prostate cancer. PeerJ 2023; 11:e14854. [PMID: 36778142 PMCID: PMC9910187 DOI: 10.7717/peerj.14854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/13/2023] [Indexed: 02/09/2023] Open
Abstract
Background Reprogramming of fatty acid metabolism is a newly-identified hallmark of malignancy. However, no studies have systematically investigated the fatty acid metabolism related-gene set in prostate cancer (PCa). Methods A cohort of 381 patients with gene expression and clinical data from The Cancer Genome Atlas was used as the training set, while another cohort of 90 patients with PCa from GEO (GSE70769) was used as the validation set. Differentially expressed fatty acid metabolism-related genes were subjected to least absolute shrinkage and selection operator (LASSO)-Cox regression to establish a fatty acid metabolism-related risk score. Associations between the risk score and clinical characteristics, immune cell infiltration, tumor mutation burden (TMB), tumor immune dysfunction and exclusion (TIDE) score, and response to chemotherapy were analyzed. Finally, the expression level of genes included in the model was validated using real-time PCR. Results A prognostic risk model based on five fatty acid metabolism related genes (ALDH1A1, CPT1B, CA2, CROT, and NUDT19) were constructed. Tumors with higher risk score were associated with larger tumor size, lymph node involvement, higher Gleason score, and poorer biochemical recurrence (BCR)-free survival. Furthermore, the high- and low-risk tumors exhibited distinct immune cell infiltration features and immune-related pathway activation. High-risk tumors were associated with favorable response to immunotherapy as indicated by high TMB and low TIDE score, but poor response to bicalutamide and docetaxel chemotherapy. Conclusion This study established a fatty acid metabolism-related gene signature which was predictive of BCR and response to chemotherapy and immunotherapy, providing a novel therapeutic biomarker for PCa.
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Affiliation(s)
- Hongjun Zhao
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Tong Wu
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Zehao Luo
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Qinyao Huang
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Sihua Zhu
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Chunling Li
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Zubing Zhang
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Jiahao Zhang
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Jianwen Zeng
- Department of Urology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan, China
| | - Yuying Zhang
- Shenzhen Longhua Maternity and Child Healthcare Hospital, Shenzhen, China
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Wassie T, Cheng B, Zhou T, Gao L, Lu Z, Wang J, Mulu B, Taye M, Wu X. Enteromorpha polysaccharide and yeast glycoprotein mixture improves growth, antioxidant activity, serum lipid profile and regulates lipid metabolism in broiler chickens. Poult Sci 2022; 101:102064. [PMID: 36055019 PMCID: PMC9445391 DOI: 10.1016/j.psj.2022.102064] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/30/2022] [Accepted: 07/19/2022] [Indexed: 11/18/2022] Open
Abstract
This study aimed to analyze the growth performance, antioxidant activity, serum lipid profile, meat quality, and lipid metabolism of broiler chickens fed mixtures containing Enteromorpha polysaccharide (EP) and yeast glycoprotein (YG). A total of 400 one-day-old broiler chickens were randomly divided into 4 treatment groups of 10 replicates with 10 birds each replicate. The dietary treatments consisted of the control group (fed basal diet), and diets supplemented with Enteromorpha polysaccharide (EP; 400 mg/kg), yeast glycoprotein (YG;400 mg/kg), and EP+YG (200 mg/kg EP + 200 mg/kg YG). Compared with the control group, EP+YG supplementation enhanced growth performance and significantly reduced (P < 0.05) serum total triglyceride (TG), cholesterol (CHOL), and low-density lipoprotein LDL levels, and increased high-density lipoprotein (HDL) levels. Besides, birds fed EP+YG supplemented diet exhibited higher (P < 0.05) serum catalase (CAT), total antioxidant capacity, superoxide dismutase (SOD), and lower malonaldehyde (MDA) activities, and upregulated expressions of related genes, such as nuclear factor-erythroid factor 2-related factor 2 (NRF2), SOD1, and glutathione peroxidase 4 (GPX4) in the liver and intestinal tissues than the control group. Interestingly, higher (P < 0.05) serum SOD and lower MDA contents were observed in the EP+YG group than in either EP or YG group, suggesting a synergetic effect. Breast meat from EP+YG supplemented group had significantly higher redness value (a*), and lower pH24, total saturated fatty acid profiles, C14:0, C16:0, C18:0 fatty acid, atherogenic index, and thrombogenicity index than meat from the control group (P < 0.05). Furthermore, the mRNA expressions of fatty acid synthesis genes were downregulated (P < 0.05), whereas lipid β-oxidation-related genes were upregulated (P < 0.05) in the liver of the EP+YG supplemented group than in the control group. Overall, our data suggest that dietary EP+YG inclusion may have a synergistic effect, and therefore improve growth performance, regulate serum biochemical indexes, enhance antioxidant activity, and modulate lipid metabolism in broilers, indicating that it is a potential feed additive for chickens.
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Affiliation(s)
- Teketay Wassie
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences; National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan, 410125, China
| | - Bei Cheng
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences; National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan, 410125, China
| | - Tiantian Zhou
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences; National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan, 410125, China
| | - Lumin Gao
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences; National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan, 410125, China
| | - Zhuang Lu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences; National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan, 410125, China
| | - Jianlin Wang
- The Hubei Provincial Key Laboratory of Yeast Function, Angel Yeast Co., Ltd, Yichang, 443003, China
| | - Bekalu Mulu
- Animal Production and Technology Department, College of Agriculture and Environmental Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Mengistie Taye
- Animal Production and Technology Department, College of Agriculture and Environmental Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Xin Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences; National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production; Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, Hunan, 410125, China; Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
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4
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Lu X, Zhong R, Sun H, Zheng B, Chen L, Miao S, Liang P. Inhibition Effect of Triglyceride Accumulation by Large Yellow Croaker Roe DHA-PC in HepG2 Cells. Mar Drugs 2019; 17:md17090485. [PMID: 31438457 PMCID: PMC6780795 DOI: 10.3390/md17090485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/08/2019] [Accepted: 08/14/2019] [Indexed: 02/07/2023] Open
Abstract
The phospholipids (PLs) of large yellow croaker (Pseudosciaena crocea, P. crocea) roe contain a high level of polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), which can lower blood lipid levels. In previous research, PLs of P. crocea roe were found able to regulate the accumulation of triglycerides. However, none of these involve the function of DHA-containing phosphatidylcholine (DHA-PC), which is the main component of PLs derived from P. crocea roe. The function by which DHA-PC from P. crocea roe exerts its effects has not yet been clarified. Herein, we used purified DHA-PC and oleic acid (OA) induced HepG2 cells to establish a high-fat model, and the cell activity and intracellular lipid levels were then measured. The mRNA and protein expression of Fatty Acid Synthase (FAS), Carnitine Palmitoyl Transferase 1A (CPT1A) and Peroxisome Proliferator-Activated Receptor α (PPARα) in HepG2 cells were detected via RT-qPCR and western blot as well. It was found that DHA-PC can significantly regulate triglyceride accumulation in HepG2 cells, the effect of which was related to the activation of PPARα receptor activity, upregulation of CPT1A, and downregulation of FAS expression. These results can improve the understanding of the biofunction of hyperlipidemia mediated by DHA-PC from P. crocea roe, as well as provide a theoretical basis for the utilization of DHA-PC from P. crocea roe as a functional food additive.
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Affiliation(s)
- Xiaodan Lu
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Rongbin Zhong
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - He Sun
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Baodong Zheng
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- China-Ireland International Cooperation Centre for Food Material Science and Structure Design, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lijiao Chen
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Song Miao
- China-Ireland International Cooperation Centre for Food Material Science and Structure Design, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Food Chemistry and Technology Department, Teagasc Food Research Centre, Moorepark, Fermoy, P61 C996 Co. Cork, Ireland
| | - Peng Liang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Key Laboratory of Marine Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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5
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Vantaku V, Dong J, Ambati CR, Perera D, Donepudi SR, Amara CS, Putluri V, Ravi SS, Robertson MJ, Piyarathna DWB, Villanueva M, von Rundstedt FC, Karanam B, Ballester LY, Terris MK, Bollag RJ, Lerner SP, Apolo AB, Villanueva H, Lee M, Sikora AG, Lotan Y, Sreekumar A, Coarfa C, Putluri N. Multi-omics Integration Analysis Robustly Predicts High-Grade Patient Survival and Identifies CPT1B Effect on Fatty Acid Metabolism in Bladder Cancer. Clin Cancer Res 2019; 25:3689-3701. [PMID: 30846479 DOI: 10.1158/1078-0432.ccr-18-1515] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 11/09/2018] [Accepted: 03/06/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE The perturbation of metabolic pathways in high-grade bladder cancer has not been investigated. We aimed to identify a metabolic signature in high-grade bladder cancer by integrating unbiased metabolomics, lipidomics, and transcriptomics to predict patient survival and to discover novel therapeutic targets. EXPERIMENTAL DESIGN We performed high-resolution liquid chromatography mass spectrometry (LC-MS) and bioinformatic analysis to determine the global metabolome and lipidome in high-grade bladder cancer. We further investigated the effects of impaired metabolic pathways using in vitro and in vivo models. RESULTS We identified 519 differential metabolites and 19 lipids that were differentially expressed between low-grade and high-grade bladder cancer using the NIST MS metabolomics compendium and lipidblast MS/MS libraries, respectively. Pathway analysis revealed a unique set of biochemical pathways that are highly deregulated in high-grade bladder cancer. Integromics analysis identified a molecular gene signature associated with poor patient survival in bladder cancer. Low expression of CPT1B in high-grade tumors was associated with low FAO and low acyl carnitine levels in high-grade bladder cancer, which were confirmed using tissue microarrays. Ectopic expression of the CPT1B in high-grade bladder cancer cells led to reduced EMT in in vitro, and reduced cell proliferation, EMT, and metastasis in vivo. CONCLUSIONS Our study demonstrates a novel approach for the integration of metabolomics, lipidomics, and transcriptomics data, and identifies a common gene signature associated with poor survival in patients with bladder cancer. Our data also suggest that impairment of FAO due to downregulation of CPT1B plays an important role in the progression toward high-grade bladder cancer and provide potential targets for therapeutic intervention.
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Affiliation(s)
- Venkatrao Vantaku
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas
| | - Jianrong Dong
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas
| | - Chandrashekar R Ambati
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | - Dimuthu Perera
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | - Sri Ramya Donepudi
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | - Chandra Sekhar Amara
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas
| | - Vasanta Putluri
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | - Shiva Shankar Ravi
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas
| | - Matthew J Robertson
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | | | - Mariana Villanueva
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | | | - Balasubramanyam Karanam
- Department of Biology and Center for Cancer Research, Tuskegee University, Tuskegee, Alabama
| | - Leomar Y Ballester
- Pathology & Laboratory Medicine, Neurosurgery, University of Texas Health Science Center, Houston, Texas
| | | | | | - Seth P Lerner
- Scott Department of Urology, Baylor College of Medicine, Houston, Texas
| | - Andrea B Apolo
- Center for Cancer Research, National Cancer Institute, Bethesda, Maryland
| | - Hugo Villanueva
- Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas
| | - MinJae Lee
- Division of Clinical and Translational Sciences, Department of Internal Medicine, McGovern Medical School at The University of Texas Health Science Center, Houston, Texas
| | - Andrew G Sikora
- Department of Otolaryngology-Head & Neck Surgery, Baylor College of Medicine, Houston, Texas
| | - Yair Lotan
- Department of Urology, University of Texas Southwestern, Dallas, Texas
| | - Arun Sreekumar
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas
| | - Cristian Coarfa
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas.,Dan L. Duncan Cancer Center, Advanced Technology Core, Alkek Center for Molecular Discovery, Baylor College of Medicine, Houston, Texas.,Center for Precision Environmental Health, Baylor College of Medicine, Houston, Texas
| | - Nagireddy Putluri
- Department of Molecular and Cell Biology, Baylor College of Medicine, Houston, Texas.
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Pucci S, Zonetti MJ, Fisco T, Polidoro C, Bocchinfuso G, Palleschi A, Novelli G, Spagnoli LG, Mazzarelli P. Carnitine palmitoyl transferase-1A (CPT1A): a new tumor specific target in human breast cancer. Oncotarget 2018; 7:19982-96. [PMID: 26799588 PMCID: PMC4991433 DOI: 10.18632/oncotarget.6964] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 01/01/2016] [Indexed: 12/03/2022] Open
Abstract
Transcriptional mechanisms epigenetically-regulated in tumoral tissues point out new targets for anti-cancer therapies. Carnitine palmitoyl transferase I (CPT1) is the rate-limiting enzyme in the transport of long-chain fatty acids for β-oxidation. Here we identified the tumor specific nuclear CPT1A as a product of the transcript variant 2, that doesn't retain the classical transferase activity and is strongly involved in the epigenetic regulation of cancer pro-survival, cell death escaping and tumor invasion pathways. The knockdown of CPT1A variant 2 by small interfering RNAs (siRNAs), was sufficient to induce apoptosis in MCF-7, SK-BR3 and MDA-MB-231 breast cancer cells. The cell death triggered by CPT1A silencing correlated with reduction of HDAC activity and histone hyperacetylation. Docking experiments and molecular dynamics simulations confirmed an high binding affinity of the variant 2 for HDAC1. The CPT1A silenced cells showed an up-regulated transcription of pro-apoptotic genes (BAD, CASP9, COL18A1) and down-modulation of invasion and metastasis related-genes (TIMP-1, PDGF-A, SERPINB2). These findings provide evidence of the CPT1 variant 2 involvement in breast cancer survival, cell death escape and invasion. Thus, we propose nuclear CPT1A as a striking tumor specific target for anticancer therapeutics, more selective and effective as compared with the well-known HDAC inhibitors.
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Affiliation(s)
- Sabina Pucci
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Maria Josè Zonetti
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Tommaso Fisco
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Chiara Polidoro
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Gianfranco Bocchinfuso
- Department of Chemical Sciences and Technologies, Tor Vergata University of Rome, Rome, Italy
| | - Antonio Palleschi
- Department of Chemical Sciences and Technologies, Tor Vergata University of Rome, Rome, Italy
| | - Giuseppe Novelli
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Luigi G Spagnoli
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
| | - Paola Mazzarelli
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, Rome, Italy
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7
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Longitudinal metabolic imaging of hepatocellular carcinoma in transgenic mouse models identifies acylcarnitine as a potential biomarker for early detection. Sci Rep 2016; 6:20299. [PMID: 26831370 PMCID: PMC4735819 DOI: 10.1038/srep20299] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/30/2015] [Indexed: 12/30/2022] Open
Abstract
The cumulative effects of hepatic injury due to hepatitis B virus (HBV) infections and aflatoxin-B1 (AFB1) exposure are the major risk factors of HCC. Understanding early metabolic changes involving these risk factors in an animal model closely resembling human hepatocellular carcinoma (HCC) is critical for biomarker discovery and disease therapeutics. We have used the hepatitis B surface antigen (HBsAg) transgenic mouse model that mimics HBV carriers with and without AFB1 treatment. We investigated early metabolic changes from preneoplastic state to HCC by non-invasive longitudinal imaging in three HCC groups of mice: HBsAg + AFB1(Gp-I), AFB1 alone (Gp-II), HBsAg alone (Gp-III) and a control group (wild-type untreated; Gp-IV). For the first time, we have identified acylcarnitine signals in vivo in the liver prior to the histological manifestation of the tumors in all three groups. Acylcarnitine concentration increased with increase in tumor growth in all HCC mouse models, indicating elevated metabolic activity and increased cell turnover. This was confirmed in a pilot study using human serum from HCC patients, which revealed a higher concentration of acylcarnitine compared with normal subjects. Translational clinical studies can be designed to detect acylcarnitine in patients with high risk factors for HCC.
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Hu W, Luo Z, Mai KS, Liu CX, Zheng JL. Ontogeny and kinetics of carnitine palmitoyltransferase I in hepatopancreas and skeletal muscle of grass carp (Ctenopharyngodon idella). FISH PHYSIOLOGY AND BIOCHEMISTRY 2015; 41:1393-1401. [PMID: 26170093 DOI: 10.1007/s10695-015-0094-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 07/06/2015] [Indexed: 06/04/2023]
Abstract
The ontogeny and kinetics of carnitine palmitoyltransferase I (CPT I) were investigated in hepatopancreas and muscle throughout four developmental stages (newly hatched larvae, 1-month-old juvenile, 3-month-old, and 6-month-old, respectively) of grass carp Ctenopharyngodon idella. In hepatopancreas, the maximal velocity (Vmax) significantly increased from hatching to 1-month-old grass carp and then gradually declined at 6-month-old grass carp. In muscle, CPT I activity was the highest at 1-month-old grass carp, nearly twofold higher than that at hatching (P < 0.05). The Michaelis constant (Km) value was also the highest for 1-month-old in both tested tissues. Carnitine concentrations (FC, AC and TC) were the lowest for 3-month-old grass carp and remained relatively constant in both tissues from fish under the other developmental stages. The FC concentration in hepatopancreas and muscle at four developmental stages were less than the respective Km, indicating that grass carp required supplemental carnitine in their food to ensure that CPT I activity was not constrained by carnitine availability.
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Affiliation(s)
- Wei Hu
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan, 430070, People's Republic of China
| | - Zhi Luo
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
- Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan, 430070, People's Republic of China.
| | - Kang-Sen Mai
- College of Fisheries, Ocean University of China, Qingdao, 266003, People's Republic of China
| | - Cai-Xia Liu
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan, 430070, People's Republic of China
- Bureau of Aquatic Products of Xiantao City, Xiantao, 433000, People's Republic of China
| | - Jia-Lang Zheng
- Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
- Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan, 430070, People's Republic of China
- National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan, 316022, People's Republic of China
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9
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Lahey R, Wang X, Carley AN, Lewandowski ED. Dietary fat supply to failing hearts determines dynamic lipid signaling for nuclear receptor activation and oxidation of stored triglyceride. Circulation 2014; 130:1790-9. [PMID: 25266948 PMCID: PMC4229424 DOI: 10.1161/circulationaha.114.011687] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Intramyocardial triglyceride (TG) turnover is reduced in pressure-overloaded, failing hearts, limiting the availability of this rich source of long-chain fatty acids for mitochondrial β-oxidation and nuclear receptor activation. This study explored 2 major dietary fats, palmitate and oleate, in supporting endogenous TG dynamics and peroxisome proliferator-activated receptor-α activation in sham-operated (SHAM) and hypertrophied (transverse aortic constriction [TAC]) rat hearts. METHODS AND RESULTS Isolated SHAM and TAC hearts were provided media containing carbohydrate with either (13)C-palmitate or (13)C-oleate for dynamic (13)C nuclear magnetic resonance spectroscopy and end point liquid chromatography/mass spectrometry of TG dynamics. With palmitate, TAC hearts contained 48% less TG versus SHAM (P=0.0003), whereas oleate maintained elevated TG in TAC, similar to SHAM. TG turnover in TAC was greatly reduced with palmitate (TAC, 46.7±12.2 nmol/g dry weight per min; SHAM, 84.3±4.9; P=0.0212), as was β-oxidation of TG. Oleate elevated TG turnover in both TAC (140.4±11.2) and SHAM (143.9±15.6), restoring TG oxidation in TAC. Peroxisome proliferator-activated receptor-α target gene transcripts were reduced by 70% in TAC with palmitate, whereas oleate induced normal transcript levels. Additionally, mRNA levels for peroxisome proliferator-activated receptor-γ-coactivator-1α and peroxisome proliferator-activated receptor-γ-coactivator-1β in TAC hearts were maintained by oleate. With these metabolic effects, oleate also supported a 25% improvement in contractility over palmitate with TAC (P=0.0202). CONCLUSIONS The findings link reduced intracellular lipid storage dynamics to impaired peroxisome proliferator-activated receptor-α signaling and contractility in diseased hearts, consistent with a rate-dependent lipolytic activation of peroxisome proliferator-activated receptor-α. In decompensated hearts, oleate may serve as a beneficial energy substrate versus palmitate by upregulating TG dynamics and nuclear receptor signaling.
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MESH Headings
- Animals
- Cardiomyopathy, Hypertrophic/complications
- Cardiomyopathy, Hypertrophic/metabolism
- Cell Nucleus/metabolism
- Ceramides/analysis
- Citric Acid Cycle
- Dietary Fats/pharmacokinetics
- Dietary Fats/pharmacology
- Disease Models, Animal
- Gene Expression Profiling
- Gene Expression Regulation/drug effects
- Heart Failure/diet therapy
- Heart Failure/etiology
- Heart Failure/metabolism
- Hypertrophy, Left Ventricular/complications
- Hypertrophy, Left Ventricular/metabolism
- Lipolysis
- Male
- Mitochondria, Heart/metabolism
- Myocardial Contraction/drug effects
- Myocardium/metabolism
- Myocytes, Cardiac/metabolism
- Nuclear Magnetic Resonance, Biomolecular
- Oleic Acid/administration & dosage
- Oleic Acid/pharmacokinetics
- Oleic Acid/pharmacology
- Oxidation-Reduction
- PPAR alpha/physiology
- Palmitates/administration & dosage
- Palmitates/pharmacokinetics
- Palmitates/pharmacology
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- Transcription, Genetic
- Triglycerides/metabolism
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Affiliation(s)
- Ryan Lahey
- From the Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago, IL
| | - Xuerong Wang
- From the Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago, IL
| | - Andrew N Carley
- From the Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago, IL
| | - E Douglas Lewandowski
- From the Center for Cardiovascular Research, University of Illinois at Chicago College of Medicine, Chicago, IL.
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10
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11
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Liu CX, Luo Z, Hu W, Tan XY, Zheng JL, Chen QL, Zhu QL. Kinetics of Carnitine Palmitoyltransferase I (CPT I) in Chinese sucker (Myxocyprinus asiaticus) Change with its Development. Lipids 2013; 49:173-81. [DOI: 10.1007/s11745-013-3864-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 11/05/2013] [Indexed: 11/30/2022]
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12
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Olpin SE. Pathophysiology of fatty acid oxidation disorders and resultant phenotypic variability. J Inherit Metab Dis 2013; 36:645-58. [PMID: 23674167 PMCID: PMC7101856 DOI: 10.1007/s10545-013-9611-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/27/2013] [Accepted: 04/10/2013] [Indexed: 12/16/2022]
Abstract
Fatty acids are a major fuel for the body and fatty acid oxidation is particularly important during fasting, sustained aerobic exercise and stress. The myocardium and resting skeletal muscle utilise long-chain fatty acids as a major source of energy. Inherited disorders affecting fatty acid oxidation seriously compromise the function of muscle and other highly energy-dependent tissues such as brain, nerve, heart, kidney and liver. Such defects encompass a wide spectrum of clinical disease, presenting in the neonatal period or infancy with recurrent hypoketotic hypoglycaemic encephalopathy, liver dysfunction, hyperammonaemia and often cardiac dysfunction. In older children, adolescence or adults there is often exercise intolerance with episodic myalgia or rhabdomyolysis in association with prolonged aerobic exercise or other exacerbating factors. Some disorders are particularly associated with toxic metabolites that may contribute to encephalopathy, polyneuropathy, axonopathy and pigmentary retinopathy. The phenotypic diversity encountered in defects of fat oxidation is partly explained by genotype/phenotype correlation and certain identifiable environmental factors but there remain many unresolved questions regarding the complex interaction of genetic, epigenetic and environmental influences that dictate phenotypic expression. It is becoming increasingly clear that the view that most inherited disorders are purely monogenic diseases is a naive concept. In the future our approach to understanding the phenotypic diversity and management of patients will be more realistically achieved from a polygenic perspective.
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Affiliation(s)
- Simon E Olpin
- Department of Clinical Chemistry, Sheffield Children's Hospital, Sheffield S10 2TH, UK.
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13
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trans-10,cis-12 conjugated linoleic acid improved growth performance, reduced lipid deposition and influenced CPT I kinetic constants of juvenile Synechogobius hasta. Lipids 2013; 48:505-12. [PMID: 23322076 DOI: 10.1007/s11745-013-3759-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/03/2013] [Indexed: 01/09/2023]
Abstract
trans-10,cis-12 (t10c12) Conjugated linoleic acid (CLA) reduced body lipid deposition in various experimental animals, but the mechanisms involved were still emerging. Carnitine palmitoyltransferase I (CPT I) catalyzes an important regulatory step in lipid metabolism. At present, no studies, to our knowledge, have evaluated the kinetic constants influenced by dietary CLA in fish. In the present study, we tested the hypothesis that changes in body lipid content in fish as a response to dietary t10c12 CLA was related to the change of CPT I kinetic constants [Michaelis constant (K m), maximal velocity and catalytic efficiency for carnitine and palmitoyl-CoA]. Juvenile Synechogobius hasta were fed three experimental diets with fish oil replaced with 0 (control), 1, or 2 % t10c12 CLA for 8 weeks. Weight gain, specific growth rate and protein efficiency rate increased with dietary t10c12 CLA level. Dietary t10c12 CLA addition significantly reduced lipid contents both in liver and muscle. Dietary CLA addition also improved CPT I activities in muscle but did not significantly influence hepatic CPT I activity. CPT I kinetic parameters (K m, V max and catalytic efficiency) were significantly influenced by t10c12 CLA. CPT I catalytic efficiencies with carnitine and palmitoyl-CoA as substrates were higher in muscle and liver of fish fed increasing t10c12 CLA. For the first time, the findings demonstrated effect of dietary CLA addition on CPT I kinetics in fish and supported our starting hypothesis that dietary t10c12 CLA addition induced alterations in CPT I kinetic constants of muscle and liver. Increased CPT I catalytic efficiency might be the main reason for reduced lipid deposition in these tissues by dietary t10c12 CLA supplementation.
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14
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Lewandowski ED, Fischer SK, Fasano M, Banke NH, Walker LA, Huqi A, Wang X, Lopaschuk GD, O'Donnell JM. Acute liver carnitine palmitoyltransferase I overexpression recapitulates reduced palmitate oxidation of cardiac hypertrophy. Circ Res 2012; 112:57-65. [PMID: 22982985 DOI: 10.1161/circresaha.112.274456] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
RATIONALE Muscle carnitine palmitoyltransferase I is predominant in the heart, but the liver isoform (liver carnitine palmitoyltransferase I [L-CPT1]) is elevated in hearts with low long chain fatty acid oxidation, such as fetal and hypertrophied hearts. OBJECTIVE This work examined the effect of acute L-CPT1 expression on the regulation of palmitate oxidation and energy metabolism in intact functioning rat hearts for comparison with findings in hypertrophied hearts. METHODS AND RESULTS L-CPT1 was expressed in vivo in rat hearts by coronary perfusion of Adv.cmv.L-CPT1 (L-CPT1, n=15) vs. phosphate-buffered saline (PBS) infusion (PBS, n=7) or empty virus (empty, n=5). L-CPT1 was elevated 5-fold at 72 hours after Adv.cmv.L-CPT1 infusion (P<0.05), but muscle carnitine palmitoyltransferase I was unaffected. Despite similar tricarboxylic acid cycle rates, palmitate oxidation rates were reduced with L-CPT1 (1.12 ± 0.29 μmol/min per gram of dry weight, mean±SE) vs. PBS (1.6 ± 0.34). Acetyl CoA production from palmitate was reduced with L-CPT1 (69 ± 0.02%; P<0.05; PBS=79 ± 0.01%; empty=81 ± 0.02%), similar to what occurs in hypertrophied hearts, and with no difference in malonyl CoA content. Glucose oxidation was elevated with L-CPT1 (by 60%). Surprisingly, L-CPT1 hearts contained elevated atrial natriuretic peptide, indicating induction of hypertrophic signaling. CONCLUSIONS The results link L-CPT1 expression to reduced palmitate oxidation in a nondiseased adult heart, recapitulating the phenotype of reduced long chain fatty acid oxidation in cardiac hypertrophy. The implications are that L-CPT1 expression induces metabolic remodeling hypertrophic signaling and that regulatory factors beyond malonyl CoA in the heart regulate long chain fatty acid oxidation via L-CPT1.
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Affiliation(s)
- E Douglas Lewandowski
- Center for Cardiovascular Research, UIC College of Medicine, 909 South Wolcott Ave, MC 801, Chicago, IL 60612, USA.
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15
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Shi ZZ, Liang JW, Zhan T, Wang BS, Lin DC, Liu SG, Hao JJ, Yang H, Zhang Y, Zhan QM, Zhang KT, Wang MR. Genomic alterations with impact on survival in esophageal squamous cell carcinoma identified by array comparative genomic hybridization. Genes Chromosomes Cancer 2011; 50:518-26. [PMID: 21484929 DOI: 10.1002/gcc.20875] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 03/07/2011] [Indexed: 11/08/2022] Open
Abstract
Risk assessment of esophageal squamous cell carcinoma (ESCC) is currently based on clinicopathological parameters. To identify genomic markers that can predict overall survival in ESCC, we performed array comparative genomic hybridization (array CGH) on a screening set of 35 tumor samples from ESCC patients. Prognosis association of the genes selected on the basis of the array CGH results was further validated by real-time PCR in two independent sample sets (n = 151 and 84). Genomic analysis revealed seven high-level amplifications and two homozygous deletions. Gain of 11q13.2 and loss of 7q34 and 18q21.1-q23 were associated with poor outcome. Gain of 11q13.2 was an independent prognostic factor and was selected for further validation. In both validation sets of samples, copy number increase of CPT1A in 11q13.2 was correlated with short overall survival (P = 0.015, n = 151 and P = 0.044, n = 84). Multivariate analysis confirmed that CPT1A gain provided prognostic information in ESCC (HR, 1.643; 95% CI: 1.076-2.509; P = 0.022; HR, 2.488; 95% CI: 1.235-5.013; P = 0.011). Immunohistochemistry showed significant correlation between strong expression of CPT1A protein and poor outcome of ESCC patients (P = 0.018, n = 73). Our data suggest that gain of CPT1A may be a candidate prognostic factor.
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Affiliation(s)
- Zhi-Zhou Shi
- State Key Laboratory of Molecular Oncology, Cancer Institute Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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16
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Energy Metabolic Phenotype of the Cardiomyocyte During Development, Differentiation, and Postnatal Maturation. J Cardiovasc Pharmacol 2010; 56:130-40. [DOI: 10.1097/fjc.0b013e3181e74a14] [Citation(s) in RCA: 410] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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17
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Guzmán-Ruiz R, Somoza B, Gil-Ortega M, Merino B, Cano V, Attané C, Castan-Laurell I, Valet P, Fernández-Alfonso MS, Ruiz-Gayo M. Sensitivity of cardiac carnitine palmitoyltransferase to malonyl-CoA is regulated by leptin: similarities with a model of endogenous hyperleptinemia. Endocrinology 2010; 151:1010-8. [PMID: 20056820 DOI: 10.1210/en.2009-1170] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Acute leptin increase as well as endogenous hyperleptinemia evoked by high-fat diets (HF) activate fatty acid metabolism in nonadipose tissues. This supports the notion that hyperleptinemia is pivotal to prevent/delay steatosis during periods of positive energy balance. We have previously shown that long-term HF spares ectopic accumulation of lipids specifically in the miocardium. Because carnitine palmitoyltransferase I (CPT-I) allows mitochondrial uptake/oxidation of fatty acids, we have hypothesized that leptin drives cardiac CPT-I activity. In the current study, hyperleptinemia was induced in C57BL/6J mice either by exogenous leptin administration or by means of HF, and the ability of malonyl-coenzyme A (malonyl-CoA) (the main endogenous inhibitor of CPT-I) to inhibit cardiac CPT was analyzed. IC(50) values of malonyl-CoA were 8.1 +/- 1.5 micromol/liter in controls vs. 69.3 +/- 5.2 micromol/liter (P < 0.01) in leptin-treated mice. This effect was also observed in cardiac explants incubated with leptin and was blocked by triciribine, a compound shown to inhibit protein kinase B (Akt) phosphorylation (pAkt). In accordance, acute leptin evoked an increase of cardiac pAkt levels, which correlated with CPT sensitivity to malonyl-CoA. Otherwise, the inhibitory effect of malonyl-CoA was hindered in HF hyperleptinemic mice, and in this case, pAkt levels also correlated with CPT sensitivity to malonyl-CoA. Our data show that leptin reduces the sensitivity of cardiac CPT-I to malonyl-CoA and suggest the involvement of an Akt-related signaling pathway in this effect. This mechanism appears to be sensitive to both acute and chronic hyperleptinemia. We conclude that this action of leptin is pivotal to drive cardiac metabolism under situations associated to hyperleptinemia.
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Affiliation(s)
- Rocío Guzmán-Ruiz
- Departamento de Ciencias Farmacéuticas y de la Alimentación, Facultad de Farmacia, Universidad Ceu-San Pablo, Urbanización Montepríncipe, Boadilla del Monte, 28668 Madrid, Spain
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18
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Lopaschuk GD, Ussher JR, Folmes CDL, Jaswal JS, Stanley WC. Myocardial fatty acid metabolism in health and disease. Physiol Rev 2010; 90:207-58. [PMID: 20086077 DOI: 10.1152/physrev.00015.2009] [Citation(s) in RCA: 1468] [Impact Index Per Article: 104.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
There is a constant high demand for energy to sustain the continuous contractile activity of the heart, which is met primarily by the beta-oxidation of long-chain fatty acids. The control of fatty acid beta-oxidation is complex and is aimed at ensuring that the supply and oxidation of the fatty acids is sufficient to meet the energy demands of the heart. The metabolism of fatty acids via beta-oxidation is not regulated in isolation; rather, it occurs in response to alterations in contractile work, the presence of competing substrates (i.e., glucose, lactate, ketones, amino acids), changes in hormonal milieu, and limitations in oxygen supply. Alterations in fatty acid metabolism can contribute to cardiac pathology. For instance, the excessive uptake and beta-oxidation of fatty acids in obesity and diabetes can compromise cardiac function. Furthermore, alterations in fatty acid beta-oxidation both during and after ischemia and in the failing heart can also contribute to cardiac pathology. This paper reviews the regulation of myocardial fatty acid beta-oxidation and how alterations in fatty acid beta-oxidation can contribute to heart disease. The implications of inhibiting fatty acid beta-oxidation as a potential novel therapeutic approach for the treatment of various forms of heart disease are also discussed.
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Affiliation(s)
- Gary D Lopaschuk
- Cardiovascular Research Group, Mazankowski Alberta Heart Institute, University of Alberta, Alberta T6G 2S2, Canada.
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19
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Pucci S, Bettuzzi S. Chapter 3: The shifting balance between CLU forms during tumor progression. Adv Cancer Res 2010; 104:25-32. [PMID: 19878771 DOI: 10.1016/s0065-230x(09)04003-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cell transformation is strictly linked to important metabolic changes which are instrumental for initial survival of cancer cells and subsequent spreading of disease. Early (i.e., anerobic glycolysis) and late metabolic changes (i.e., fatty acid metabolism) are required for progression and clinical emergence of cancer. Besides well-known tumor suppressors and oncogenes, several metabolic genes have been found implicated in this multistep process, among which are fatty acid synthase (FASN) and carnitine palmitoyl transferase I (CPT I). An intriguing link between these metabolic shifts and a change in the balance between nuclear and secreted forms of CLU (nCLU/sCLU) has been suggested. The shifting balance between CLU forms during tumor progression, by affecting the fate of the cell, seems to be strongly influenced by the metabolic shift occurring in the different steps of tumor progression.
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Affiliation(s)
- Sabina Pucci
- Department of Biopathology, University of Rome Tor Vergata, Rome, Italy
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20
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Rufer AC, Thoma R, Hennig M. Structural insight into function and regulation of carnitine palmitoyltransferase. Cell Mol Life Sci 2009; 66:2489-501. [PMID: 19430727 PMCID: PMC11115844 DOI: 10.1007/s00018-009-0035-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2009] [Revised: 03/18/2009] [Accepted: 04/09/2009] [Indexed: 01/07/2023]
Abstract
The control of fatty acid translocation across the mitochondrial membrane is mediated by the carnitine palmitoyltransferase (CPT) system. Modulation of its functionality has simultaneous effects on fatty acid and glucose metabolism. This encourages use of the CPT system as drug target for reduction of gluconeogenesis and restoration of lipid homeostasis, which are beneficial in the treatment of type 2 diabetes mellitus and obesity. Recently, crystal structures of CPT-2 were determined in uninhibited forms and in complexes with inhibitory substrate-analogs with anti-diabetic properties in animal models and in clinical studies. The CPT-2 crystal structures have advanced understanding of CPT structure-function relationships and will facilitate discovery of novel inhibitors by structure-based drug design. However, a number of unresolved questions regarding the biochemistry and pharmacology of CPT enzymes remain and are addressed in this review.
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Affiliation(s)
- Arne C. Rufer
- F. Hoffmann-La Roche AG, Pharma Research Discovery Technologies, 4070 Basel, Switzerland
| | - Ralf Thoma
- F. Hoffmann-La Roche AG, Pharma Research Discovery Technologies, 4070 Basel, Switzerland
| | - Michael Hennig
- F. Hoffmann-La Roche AG, Pharma Research Discovery Technologies, 4070 Basel, Switzerland
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21
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Mass spectrometric demonstration of the presence of liver carnitine palmitoyltransferase-I (CPT-I) in heart mitochondria of adult rats. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:431-7. [PMID: 19111953 DOI: 10.1016/j.bbapap.2008.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 10/17/2008] [Accepted: 11/07/2008] [Indexed: 01/03/2023]
Abstract
The carnitine palmitoyltransferase-I (CPT-I) enzymes catalyze the regulated step in overall mitochondrial fatty acid oxidation. The liver and muscle isoforms are expressed in liver and skeletal muscle respectively with the isoforms exhibiting different kinetic properties and apparent molecular weight masses. In contrast, the heart expresses both isoforms at the mRNA level. However, for the expression of the liver isoform at the protein level only indirect evidence is available, such as tagging with radiolabeled CPT-I inhibitors followed by SDS-PAGE separation and kinetic analysis using inhibitors. The importance of fatty acid oxidation in the heart and the potential regulation via the liver isoform of CPT-I demands proof of the liver isoform in the heart. Using a proteomic approach in the present study we demonstrate that rat heart mitochondria (a) contain both the muscle and liver isoforms; (b) both proteins retain their C- and N-termini; (c) the N-terminal alanine residues are acetylated; (d) and in rat heart mitochondria the liver isoform is phosphorylated on tyrosine 281. By providing amino acid sequence information this is the first unequivocal demonstration that the liver isoform of CPT-I is expressed at the protein level in adult rat heart mitochondria and that the apparent smaller molecular size of the muscle isoform is not due to proteolytic truncation.
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22
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Liu HY, Zheng G, Zhu H, Woldegiorgis G. Hormonal and nutritional regulation of muscle carnitine palmitoyltransferase I gene expression in vivo. Arch Biochem Biophys 2007; 465:437-42. [PMID: 17673163 DOI: 10.1016/j.abb.2007.06.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 06/20/2007] [Accepted: 06/21/2007] [Indexed: 11/29/2022]
Abstract
Transgenic mice carrying the human heart muscle carnitine palmitoyltransferase I (M-CPTI) gene fused to a CAT reporter gene were generated to study the regulation of M-CPTI gene expression. When the mice were fasted for 48 h, CAT activity and mRNA levels increased by more than 2-fold in heart and skeletal muscle, but not liver or kidney. In the diabetic transgenic mice, there was a 2- to 3-fold increase in CAT activity and CAT mRNA levels in heart and skeletal muscle which upon insulin administration reverted to that observed with the control insulin sufficient transgenic mice. Feeding a high fat diet increased CAT activity and mRNA levels by 2- to 4-fold in heart and skeletal muscle of the transgenic mice compared to the control transgenic mice on regular diet. Overall, the M-CPTI promoter was found to be necessary for the tissue-specific hormonal and dietary regulation of the gene expression.
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Affiliation(s)
- Hong Yan Liu
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR 97006-8921, USA
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Abstract
Carnitine, the L-beta-hydroxy-gamma-N-trimethylaminobutyric acid, is synthesized primarily in the liver and kidneys from lysine and methionine. Carnitine covers an important role in lipid metabolism, acting as an obligatory cofactor for beta-oxidation of fatty acids by facilitating the transport of long-chain fatty acids across the mitochondrial membrane as acylcarnitine esters. Furthermore, since carnitine behaves as a shuttle for acetyl groups from inside to outside the mitochondrial membrane, it covers also a key role in glucose metabolism and assists in fuel-sensing. A reduction of the fatty acid transport inside the mitochondria results in the cytosolic accumulation of triglycerides, which is implicated in the pathogenesis of insulin resistance. Acute hypercarnitinemia stimulates nonoxidative glucose disposal during euglycemic hyperinsulinemic clamp in healthy volunteers. Similar results were obtained in type 2 diabetic patients. The above findings were confirmed in healthy volunteers using the minimal modeling of glucose kinetics. The total end-clamp glucose tissue uptake was significantly increased by the administration of doses of acetyl-L-carnitine (ALC) from 3.8 to 5.2 mg/kg/min, without a significant dose-response effect. In conclusion, both L-carnitine and ALC are effective in improving insulin-mediated glucose disposal either in healthy subjects or in type 2 diabetic patients. Two possible mechanisms might be invoked in the metabolic effect of carnitine and its derivative: the first is a regulation of acetyl and acyl cellular trafficking for correctly meeting the energy demand; the second is a control action in the synthesis of key glycolytic and gluconeogenic enzymes.
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Affiliation(s)
- Geltrude Mingrone
- Department of Internal Medicine, Catholic University, School of Medicine, 00135 Roma, Italy.
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Ala-Rämi A, Ylihautala M, Ingman P, Hassinen IE. Influence of calcium-induced workload transitions and fatty acid supply on myocardial substrate selection. Metabolism 2005; 54:410-20. [PMID: 15736122 DOI: 10.1016/j.metabol.2004.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Because of differences in energy yield and oxygen demand, the selection of oxidative fuels is important in the hypoxic or ischemic heart muscle. The aim of the present study was to clarify the contradictions observed in the effects of workload and fatty acid supply on myocardial fuel preference in isolated perfused rat hearts. Nuclear magnetic resonance spectroscopy combined with the administration of substrates labeled with the stable isotope carbon 13 and isotopomer analysis of glutamate labeling offers an opportunity to simultaneously measure metabolic fluxes in pathways feeding into the tricarboxylic acid (TCA) cycle. The work output was modulated by changes in extracellular calcium. In the presence of 5 mmol/L glucose, 0.5 mmol/L octanoate in the perfusate dominated the oxidative metabolism, and workload had little effect on the ratio of glucose to fatty acid utilization. This was the case even when the octanoate concentration was lowered to 50 micromol/L. The relative rate of replenishment of the TCA cycle intermediates was higher at a low workload. The redox state of flavoproteins in the intact heart was monitored fluorometrically to obtain an estimate of the mitochondrial reduced/oxidized nicotinamide-adenine dinucleotide ratio (NADH/NAD ratio) for assessment of the dominant level of regulation of cell respiration, and the myoglobin spectrum was simultaneously monitored to evaluate the oxygenation status of the myocardium. Commencement of octanoate infusion (50 micromol/L or 0.5 mmol/L) caused a large but transient reduction of mitochondrial NAD and, conversely, its cessation elicited NADH oxidation and rebound reduction. During glucose oxidation, an increase in workload led to oxidation of the mitochondrial NADH, but this effect was much smaller in the presence of 50 micromol/L octanoate and absent in the presence of 0.5 mmol/L. This indicates that strong control of oxygen consumption during glucose oxidation is exerted in the mitochondrial respiratory chain, whereas equal control during fatty acid oxidation is exerted within the metabolic pathway upstream from the respiratory chain. It is concluded that when a medium-chain fatty acid is available, myocardial workload and energy consumption have little influence on fuel preference and glucose oxidation remains suppressed.
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Affiliation(s)
- Antti Ala-Rämi
- Department of Medical Biochemistry and Molecular Biology, University of Oulu, FIN-90014 Oulu, Finland
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Tu Y, Thupari JN, Kim EK, Pinn ML, Moran TH, Ronnett GV, Kuhajda FP. C75 alters central and peripheral gene expression to reduce food intake and increase energy expenditure. Endocrinology 2005; 146:486-93. [PMID: 15498887 DOI: 10.1210/en.2004-0976] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
C75, a synthetic inhibitor of fatty acid synthase (FAS), causes anorexia and profound weight loss in lean and genetically obese mice. C75 also acts as a stimulator of carnitine palmitoyltransferase-1 to induce fatty acid oxidation. To approximate human obesity, we used a 2-wk C75 treatment model for diet-induced obese (DIO) mice to investigate the central and peripheral effects of C75 on gene expression. C75 treatment decreased food intake, increased energy expenditure, and reduced body weight more effectively in DIO than in lean mice. Analysis of the gene expression changes in hypothalamus demonstrated that the reduced food intake in C75-treated DIO mice might be mediated by inhibition of orexigenic neuropeptide expression and induction of anorexigenic neuropeptide expression. Gene expression changes in peripheral tissues indicated that C75 increased energy expenditure by the induction of genes involved in fatty acid oxidation. C75 also inhibited the expression of genes in peripheral tissues responsible for fatty acid synthesis and accumulation. The patterns of the changes in central and peripheral gene expression that occur with C75 treatment provide mechanisms to explain the reduced food intake and increased energy expenditure observed with C75.
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Affiliation(s)
- Yajun Tu
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Liu H, Zheng G, Treber M, Dai J, Woldegiorgis G. Cysteine-scanning mutagenesis of muscle carnitine palmitoyltransferase I reveals a single cysteine residue (Cys-305) is important for catalysis. J Biol Chem 2004; 280:4524-31. [PMID: 15579906 DOI: 10.1074/jbc.m400893200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carnitine palmitoyltransferase (CPT) I catalyzes the conversion of long-chain fatty acyl-CoAs to acyl carnitines in the presence of l-carnitine, a rate-limiting step in the transport of long-chain fatty acids from the cytoplasm to the mitochondrial matrix. To determine the role of the 15 cysteine residues in the heart/skeletal muscle isoform of CPTI (M-CPTI) on catalytic activity and malonyl-CoA sensitivity, we constructed a 6-residue N-terminal, a 9-residue C-terminal, and a 15-residue cysteineless M-CPTI by cysteine-scanning mutagenesis. Both the 9-residue C-terminal mutant enzyme and the complete 15-residue cysteineless mutant enzyme are inactive but that the 6-residue N-terminal cysteineless mutant enzyme had activity and malonyl-CoA sensitivity similar to those of wild-type M-CPTI. Mutation of each of the 9 C-terminal cysteines to alanine or serine identified a single residue, Cys-305, to be important for catalysis. Substitution of Cys-305 with Ala in the wild-type enzyme inactivated M-CPTI, and a single change of Ala-305 to Cys in the 9-residue C-terminal cysteineless mutant resulted in an 8-residue C-terminal cysteineless mutant enzyme that had activity and malonyl-CoA sensitivity similar to those of the wild type, suggesting that Cys-305 is the residue involved in catalysis. Sequence alignments of CPTI with the acyltransferase family of enzymes in the GenBank led to the identification of a putative catalytic triad in CPTI consisting of residues Cys-305, Asp-454, and His-473. Based on the mutagenesis and substrate labeling studies, we propose a mechanism for the acyltransferase activity of CPTI that uses a catalytic triad composed of Cys-305, His-473, and Asp-454 with Cys-305 serving as a probable nucleophile, thus acting as a site for covalent attachment of the acyl molecule and formation of a stable acyl-enzyme intermediate. This would in turn allow carnitine to act as a second nucleophile and complete the acyl transfer reaction.
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Affiliation(s)
- Hongyan Liu
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health & Science University, Beaverton, Oregon 97006-8921, USA
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27
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Sambandam N, Steinmetz M, Chu A, Altarejos JY, Dyck JRB, Lopaschuk GD. Malonyl-CoA decarboxylase (MCD) is differentially regulated in subcellular compartments by 5′AMP-activated protein kinase (AMPK). ACTA ACUST UNITED AC 2004; 271:2831-40. [PMID: 15206948 DOI: 10.1111/j.1432-1033.2004.04218.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Malonyl-CoA, a potent inhibitor of carnitine pamitoyl transferase-I (CPT-I), plays a pivotal role in fuel selection in cardiac muscle. Malonyl-CoA decarboxylase (MCD) catalyzes the degradation of malonyl-CoA, removes a potent allosteric inhibition on CPT-I and thereby increases fatty acid oxidation in the heart. Although MCD has several Ser/Thr phosphorylation sites, whether it is regulated by AMP-activated protein kinase (AMPK) has been controversial. We therefore overexpressed MCD (Ad.MCD) and constitutively active AMPK (Ad.CA-AMPK) in H9c2 cells, using an adenoviral gene delivery approach in order to examine if MCD is regulated by AMPK. Cells infected with Ad.CA-AMPK demonstrated a fourfold increase in AMPK activity as compared with control cells expressing green fluorescent protein (Ad.GFP). MCD activity increased 40- to 50-fold in Ad.MCD + Ad.GFP cells when compared with Ad.GFP control. Co-expressing AMPK with MCD further augmented MCD expression and activity in Ad.MCD + Ad.CA-AMPK cells compared with the Ad.MCD + Ad.GFP control. Subcellular fractionation further revealed that 54.7 kDa isoform of MCD expression was significantly higher in cytosolic fractions of Ad.MCD + Ad.CA-AMPK cells than of the Ad.MCD +Ad.GFP control. However, the MCD activities in cytosolic fractions were not different between the two groups. Interestingly, in the mitochondrial fractions, MCD activity significantly increased in Ad.MCD + Ad.CA-AMPK cells when compared with Ad.MCD + Ad.GFP cells. Using phosphoserine and phosphothreonine antibodies, no phosphorylation of MCD by AMPK was observed. The increase in MCD activity in mitochondria-rich fractions of Ad.MCD + Ad.CA-AMPK cells was accompanied by an increase in the level of the 50.7 kDa isoform of MCD protein in the mitochondria. This differential regulation of MCD expression and activity in the mitochondria by AMPK may potentially regulate malonyl-CoA levels at sites nearby CPT-I on the mitochondria.
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Affiliation(s)
- Nandakumar Sambandam
- Department of Pediatrics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Canada
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Cheng L, Ding G, Qin Q, Xiao Y, Woods D, Chen YE, Yang Q. Peroxisome proliferator-activated receptor delta activates fatty acid oxidation in cultured neonatal and adult cardiomyocytes. Biochem Biophys Res Commun 2004; 313:277-86. [PMID: 14684157 DOI: 10.1016/j.bbrc.2003.11.127] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARalpha, -gamma and -delta) are nuclear receptors involved in transcriptional regulations of lipid metabolism. The effect of PPARalpha in regulation of cardiac fatty acid oxidation has been well characterized. Whether PPARdelta also independently regulates fatty acid oxidation in the heart remains unclear. In this study, we tested the hypothesis that PPARdelta activates fatty acids oxidation in cardiomyocytes through transcriptional activation that are independent of PPARalpha. Our results first indicate that PPARdelta abundantly expresses in nucleus of cardiomyocytes. Palmitate oxidation rates were significantly increased in both neonatal and adult cardiomyocytes after treatment of a PPARdelta-selective ligand (GW0742). Further increases of fatty acid oxidation were evident when the treatment was applied to cardiomyocytes overexpressing a wild type PPARdelta, but not a mutant PPARdelta that lacks the intact carboxyl ligand-binding domain. Furthermore, genes of fatty acid oxidation enzymes were significantly upregulated in cultured rat neonatal cardiomyocytes when exposed to GW0742. GW0742 can restore partly the expression of certain key genes of fatty acid oxidation in mouse adult cardiomyocytes isolated from PPARalpha knockout mice. Therefore, while active crosstalk between PPARdelta and -alpha may exist, PPARdelta regulates cardiac fatty acid oxidation in the heart at least partly independent of PPARalpha. We conclude that PPARdelta may play a key role in cardiac energy balance and may serve as a "sensor" of fatty acid of other endogenous ligands in controlling fatty acids oxidation levels in the hearts under normal and pathological conditions.
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Affiliation(s)
- Lihong Cheng
- Cardiovascular Research Institute, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310, USA
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29
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Yamazaki N. Identification of Muscle-Type Carnitine Palmitoyltransferase I and Characterization of Its Atypical Gene Structure. Biol Pharm Bull 2004; 27:1707-16. [PMID: 15516711 DOI: 10.1248/bpb.27.1707] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To characterize energy metabolism in rat brown adipose tissue (BAT), we carried out differential screening of a cDNA library of BAT with a cDNA probe of white adipose tissue and isolated one novel cDNA clone. It contained a single open-reading frame of 2316 bases, which encodes a protein of 88.2 kDa. The predicted amino acid sequence showed the highest homology (62.6%) with that of carnitine palmitoyltransferase I (CPTI) from rat liver. The transcript corresponding to this cDNA was found to be abundantly expressed not only in BAT but also in heart and skeletal muscle. CPTI is known to be a protein necessary for the beta-oxidation of long-chain fatty acids in mammalian mitochondria, and it has been suggested that at least two isoforms, the liver type and muscle type, exist. From these observations, a cDNA clone isolated from rat BAT was concluded to be encoding muscle-type CPTI (M-CPTI). Characterization of a genomic DNA clone revealed that the gene for human M-CPTI consists of two 5'-noncoding exons, 18 coding exons, and one 3'-noncoding exon spanning approximately 10 kbp, and a gene encoding choline/ethanolamine kinase-beta (CK/EK-beta) was located only about 300 bp upstream from the M-CPTI gene with the same strand direction. Furthermore, we found that unordinary transcripts containing exons of both CK/EK-beta and M-CPTI genes exist in human and rodent tissues. Although the physiologic role(s) of these transcripts is still unknown, it is interesting that such transcripts are produced from two tightly arranged and functionally unrelated genes.
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Affiliation(s)
- Naoshi Yamazaki
- Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
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Wightman PJ, Santer R, Ribes A, Dougherty F, McGill N, Thorburn DR, FitzPatrick DR. MLYCD mutation analysis: evidence for protein mistargeting as a cause of MLYCD deficiency. Hum Mutat 2003; 22:288-300. [PMID: 12955715 DOI: 10.1002/humu.10264] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Malonyl-CoA decarboxylase (MLYCD) deficiency is an autosomal recessive disorder characterized by malonic aciduria, developmental delay, seizure disorder, hypoglycemia, and cardiomyopathy. Genomic sequencing of MLYCD in nine unrelated patients identified 16 of 18 pathogenic alleles, which are documented in the newly created Human MLYCD Allelic Variant Database (http://mlycd.hgu.mrc.ac.uk/). Fibroblast cell lines were available from eight of these patients and two previously reported patients with homozygous MLYCD mutations. Western blot analysis using antisera raised to a C-terminal peptide detected a 66-kDa band that was absent in six patients and substantially reduced in three patients. One patient showed an increase in protein levels with a prominent smeary 68-l83-kDa band. Immunocytochemical analysis of MLYCD-expressing patient cell lines showed apparent intracellular mislocalization. An extreme N-terminal mutation c.8G>A (p.G3D) mislocalized to the plasma membrane, suggesting that a novel targeting signal may reside in a four-amino acid conserved N-terminal motif. A 25-base deletion between the putative mitochondrial and peroxisomal initiating codons (M1 and M40) and a point mutation ablating the second of these (c.119T>C, p.M40T) both showed punctate perinuclear staining. As none of the three mislocalizing mutations are predicted to alter the catalytic function of the peptide, it seems likely that correct subcellular localization of MLYCD is critical for it to function normally.
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Affiliation(s)
- P J Wightman
- Medical Research Council Human Genetics Unit, Western General Hospital, Edinburgh, UK
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31
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Napal L, Dai J, Treber M, Haro D, Marrero PF, Woldegiorgis G. A single amino acid change (substitution of the conserved Glu-590 with alanine) in the C-terminal domain of rat liver carnitine palmitoyltransferase I increases its malonyl-CoA sensitivity close to that observed with the muscle isoform of the enzyme. J Biol Chem 2003; 278:34084-9. [PMID: 12826662 DOI: 10.1074/jbc.m305826200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carnitine palmitoyltransferase I (CPTI) catalyzes the conversion of long-chain fatty acyl-CoAs to acylcarnitines in the presence of l-carnitine. To determine the role of the highly conserved C-terminal glutamate residue, Glu-590, on catalysis and malonyl-CoA sensitivity, we separately changed the residue to alanine, lysine, glutamine, and aspartate. Substitution of Glu-590 with aspartate, a negatively charged amino acid with only one methyl group less than the glutamate residue in the wild-type enzyme, resulted in complete loss in the activity of the liver isoform of CPTI (L-CPTI). A change of Glu-590 to alanine, glutamine, and lysine caused a significant 9- to 16-fold increase in malonyl-CoA sensitivity but only a partial decrease in catalytic activity. Substitution of Glu-590 with neutral uncharged residues (alanine and glutamine) and/or a basic positively charged residue (lysine) significantly increased L-CPTI malonyl-CoA sensitivity to the level observed with the muscle isoform of the enzyme, suggesting the importance of neutral and/or positive charges in the switch of the kinetic properties of L-CPTI to the muscle isoform of CPTI. Since a conservative substitution of Glu-590 to aspartate but not glutamine resulted in complete loss in activity, we suggest that the longer side chain of glutamate is essential for catalysis and malonyl-CoA sensitivity. This is the first demonstration whereby a single residue mutation in the C-terminal region of the liver isoform of CPTI resulted in a change of its kinetic properties close to that observed with the muscle isoform of the enzyme and provides the rationale for the high malonyl-CoA sensitivity of muscle CPTI compared with the liver isoform of the enzyme.
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Affiliation(s)
- Laura Napal
- Department of Environmental and Biomolecular Systems, OGI School of Science & Engineering, Oregon Health & Science University, Beaverton, Oregon 97006-8921, USA
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32
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Zhu H, Shi J, Treber M, Dai J, Arvidson DN, Woldegiorgis G. Substitution of glutamate-3, valine-19, leucine-23, and serine-24 with alanine in the N-terminal region of human heart muscle carnitine palmitoyltransferase I abolishes malonyl CoA inhibition and binding. Arch Biochem Biophys 2003; 413:67-74. [PMID: 12706342 DOI: 10.1016/s0003-9861(03)00081-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The muscle isoform of carnitine palmitoyltransferase I (M-CPTI) is 30- to 100-fold more sensitive to malonyl CoA inhibition than the liver isoform (L-CPTI). We have previously shown that deletion of the first 28 N-terminal amino acid residues in M-CPTI abolished malonyl CoA inhibition and high-affinity binding [Biochemistry 39 (2000) 712-717]. To determine the role of specific residues within the first 28 N-terminal amino acids of human heart M-CPTI on malonyl CoA sensitivity and binding, we constructed a series of substitution mutations and a mutant M-CPTI composed of deletion 18 combined with substitution mutations V19A, L23A, and S24A. All mutants had CPT activity similar to that of the wild type. A change of Glu3 to Ala resulted in a 60-fold decrease in malonyl CoA sensitivity and loss of high-affinity malonyl CoA binding. A change of His5 to Ala in M-CPTI resulted in only a 2-fold decrease in malonyl CoA sensitivity and a significant loss in the low- but not high-affinity malonyl CoA binding. Deletion of the first 18 N-terminal residues combined with substitution mutations V19A, L23A, and S24A resulted in a mutant M-CPTI with an over 140-fold decrease in malonyl CoA sensitivity and a significant loss in both high- and low-affinity malonyl CoA binding. This was further confirmed by a combined four-residue substitution of Glu3, Val19, Leu23, and Ser24 with alanine. Our site-directed mutagenesis studies demonstrate that Glu3, Val19, Leu23, and Ser24 in M-CPTI are important for malonyl CoA inhibition and binding, but not for catalysis.
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Affiliation(s)
- Hongfa Zhu
- Department of Biochemistry and Molecular Biology, OGI School of Science and Engineering, Oregon Health and Science University, 20000 N.W. Walker Road, Beaverton 97006-8921, USA
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33
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Gutières S, Damon M, Panserat S, Kaushik S, Médale F. Cloning and tissue distribution of a carnitine palmitoyltransferase I gene in rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol B Biochem Mol Biol 2003; 135:139-51. [PMID: 12781981 DOI: 10.1016/s1096-4959(03)00074-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The carnitine palmitoyltransferase I (EC.2.3.1.21; CPT I) mediates the transport of fatty acids across the outer mitochondrial membrane. In mammals, there are two different proteins CPT I in the skeletal muscle (M) and liver (L) encoded by two genes. The carnitine palmitoyltransferase system of lower vertebrates received little attention. With the aim of improving knowledge on the CPT family in fish, we examined CPT I cDNA and CPT activity in different tissues of rainbow trout (Oncorhynchus mykiss). Using RT-PCR, we successfully cloned a partial CPT I cDNA sequence (1650 bp). The predicted protein sequence revealed identities of 63% and 61% with human L-CPT I and M-CPT I, respectively. This mRNA is expressed in liver, white and red skeletal muscles, heart, intestine, kidney and adipose tissue of trout. This is in good agreement with the measurement of the CPT activity in the same tissues. The [IC(50)] that reflects the sensitivity to malonyl-CoA inhibition was 0.116+/-0.004 microM for the liver and 0.426+/-0.041 microM for the white muscle. These results demonstrate for the first time the existence of at least one gene encoding for CPT I present in both the liver and the muscle of rainbow trout.
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Affiliation(s)
- Stéphanie Gutières
- Fish Nutrition Laboratory, Unité mixte INRA-IFREMER, Saint-Pée-sur-Nivelle 64310, France
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34
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Bartlett K, Pourfarzam M. Defects of beta-oxidation including carnitine deficiency. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 53:469-516. [PMID: 12512350 DOI: 10.1016/s0074-7742(02)53017-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- K Bartlett
- Department of Child Health, Department of Clinical Biochemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 4LP, United Kingdom
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35
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Treber M, Dai J, Woldegiorgis G. Identification by mutagenesis of conserved arginine and glutamate residues in the C-terminal domain of rat liver carnitine palmitoyltransferase I that are important for catalytic activity and malonyl-CoA sensitivity. J Biol Chem 2003; 278:11145-9. [PMID: 12540837 DOI: 10.1074/jbc.m210566200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carnitine palmitoyltransferase I (CPTI) catalyzes the conversion of long chain fatty acyl-CoAs to acylcarnitines in the presence of l-carnitine. To determine the role of the conserved glutamate residue, Glu-603, on catalysis and malonyl-CoA sensitivity, we separately changed the residue to alanine, histidine, glutamine, and aspartate. Substitution of Glu-603 with alanine or histidine resulted in complete loss of L-CPTI activity. A change of Glu-603 to glutamine caused a significant decrease in catalytic activity and malonyl-CoA sensitivity. Substitution of Glu-603 with aspartate, a negatively charged amino acid with only one methyl group less than the glutamate residue in the wild type enzyme, resulted in partial loss in CPTI activity and a 15-fold decrease in malonyl-CoA sensitivity. The mutant L-CPTI with a replacement of the conserved Arg-601 or Arg-606 with alanine also showed over 40-fold decrease in malonyl-CoA sensitivity, suggesting that these two conserved residues may be important for substrate and inhibitor binding. Since a conservative substitution of Glu-603 to aspartate or glutamine resulted in partial loss of activity and malonyl-CoA sensitivity, it further suggests that the negative charge and the longer side chain of glutamate are essential for catalysis and malonyl-CoA sensitivity. We predict that this region of L-CPTI spanning these conserved C-terminal residues may be the region of the protein involved in binding the CoA moiety of palmitoyl-CoA and malonyl-CoA and/or the putative low affinity acyl-CoA/malonyl-CoA binding site.
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Affiliation(s)
- Michelle Treber
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health & Science University, Beaverton, Oregon 97006-8921
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36
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Dai J, Zhu H, Woldegiorgis G. Leucine-764 near the extreme C-terminal end of carnitine palmitoyltransferase I is important for activity. Biochem Biophys Res Commun 2003; 301:758-63. [PMID: 12565845 DOI: 10.1016/s0006-291x(03)00042-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Muscle carnitine palmitoyltransferase I (M-CPTI) catalyzes the conversion of long-chain fatty acyl-CoAs to acylcarnitines in the presence of L-carnitine. To determine the role of the C-terminal region of M-CPTI in enzyme activity, we constructed a series of deletion and substitution mutants. The mutants were expressed in the yeast Pichia pastoris, and the effect of the mutations on M-CPTI activity and malonyl-CoA sensitivity was determined in isolated mitochondria prepared from the yeast strains expressing the wild-type and deletion mutants. Deletion of the last 210, 113, 44, 20, 10, and 9 C-terminal amino-acid residues resulted in an inactive M-CPTI, but deletion of the last 8, 7, 6, and 3 C-terminal residues had no effect on activity, demonstrating that leucine-764 (L764) is essential for catalysis. Substitution of L764 with alanine caused a 40% loss in catalytic activity, but replacement of L764 with arginine resulted in an 84% loss of activity; substitution of L764 with valine had no effect on catalytic activity. The catalytic efficiency for the L764R mutant decreased by 80% for both substrates. Secondary structure prediction of the M-CPTI sequence identified a 21-amino-acid residue, 744-764, predicted to fold into a coiled-coil alpha-helix in the extreme C-terminal region of M-CPTI that may be important for native folding and activity. In summary, our data demonstrate that deletion of L764 or substitution with arginine inactivates the enzyme, suggesting that L764 may be important for proper folding of M-CPTI and optimal activity.
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Affiliation(s)
- Jia Dai
- Department of Biochemistry and Molecular Biology, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR 97006-8921, USA
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37
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Onay-Besikci A, Campbell FM, Hopkins TA, Dyck JRB, Lopaschuk GD, Onay Besikci A. Relative importance of malonyl CoA and carnitine in maturation of fatty acid oxidation in newborn rabbit heart. Am J Physiol Heart Circ Physiol 2003; 284:H283-9. [PMID: 12388233 DOI: 10.1152/ajpheart.00461.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
After birth, a dramatic increase in fatty acid oxidation occurs in the heart, which has been attributed to an increase in l-carnitine levels and a switch from the liver (L) to muscle (M) isoform of carnitine palmitoyltransferase (CPT)-1. However, because M-CPT-1 is more sensitive to inhibition by malonyl CoA, a potent endogenous regulator of fatty acid oxidation, a switch to the M-CPT-1 isoform should theoretically decrease fatty acid oxidation. Because of this discrepancy, we assessed the contributions of myocardial l-carnitine content and CPT-1 isoform expression and kinetics to the maturation of fatty acid oxidation in newborn rabbit hearts. Although fatty acid oxidation rates increased between 1 and 14 days after birth, myocardial l-carnitine concentrations did not increase. Changes in the expression of L-CPT-1 or M-CPT-1 mRNA after birth also did not parallel the increase in fatty acid oxidation. The K(m) of CPT-1 for carnitine and the IC(50) for malonyl CoA remained unchanged between 1 and 10 days after birth. However, malonyl CoA levels dramatically decreased, due in part to an increase in malonyl CoA decarboxylase activity. Our data suggest that a decrease in malonyl CoA control of CPT-1 is primarily responsible for the increase in fatty acid oxidation seen in the newborn heart.
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Affiliation(s)
- Arzu Onay-Besikci
- Department of Pharmacology, University of Alberta, Edmonton, Canada T6G 2S2
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38
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Lopaschuk GD. Malonyl CoA control of fatty acid oxidation in the diabetic rat heart. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2002; 498:155-65. [PMID: 11900364 DOI: 10.1007/978-1-4615-1321-6_21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Increased fatty acid metabolism can decrease cardiac function and efficiency, and may therefore contribute to the outcome of ischemic injury in the diabetic. Alterations in the control of myocardial malonyl CoA levels is an important contributing factor to these high fatty acid oxidation rates. This includes alterations in AMPK, ACC, and MCD activity in the diabetic rat heart. A further understanding of how malonyl CoA controls fatty acid oxidation in the diabetic heart should help identify new targets for pharmacological intervention which decreases the reliance of the heart on fatty acid oxidation, and ultimately improves heart function.
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Affiliation(s)
- G D Lopaschuk
- Cardiovascular Research Group, University of Alberta, Edmonton, Canada
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39
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Abstract
The control of mitochondrial beta-oxidation, including the delivery of acyl moieties from the plasma membrane to the mitochondrion, is reviewed. Control of beta-oxidation flux appears to be largely at the level of entry of acyl groups to mitochondria, but is also dependent on substrate supply. CPTI has much of the control of hepatic beta-oxidation flux, and probably exerts high control in intact muscle because of the high concentration of malonyl-CoA in vivo. beta-Oxidation flux can also be controlled by the redox state of NAD/NADH and ETF/ETFH(2). Control by [acetyl-CoA]/[CoASH] may also be significant, but it is probably via export of acyl groups by carnitine acylcarnitine translocase and CPT II rather than via accumulation of 3-ketoacyl-CoA esters. The sharing of control between CPTI and other enzymes allows for flexible regulation of metabolism and the ability to rapidly adapt beta-oxidation flux to differing requirements in different tissues.
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Affiliation(s)
- Simon Eaton
- Surgery Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
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40
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Affiliation(s)
- J Denis McGarry
- Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9135, USA.
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41
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Invernizzi F, Burlina AB, Donadio A, Giordano G, Taroni F, Garavaglia B. Lethal neonatal presentation of carnitine palmitoyltransferase I deficiency. J Inherit Metab Dis 2001; 24:601-2. [PMID: 11757589 DOI: 10.1023/a:1012476029536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A neonate subsequently diagnosed with carnitine palmitoyltransferase I deficiency died at 34 h of untreatable bradycardia. There was fatty infiltration of the liver and increased free carnitine and reduced acylcarnitines in the blood.
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Affiliation(s)
- F Invernizzi
- Divisione di Biochimica e Genetica, Istituto Nazionale Neurologico C. Besta, Milan, Italy
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42
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Eaton S, Bartlett K, Quant PA. Carnitine palmitoyl transferase I and the control of beta-oxidation in heart mitochondria. Biochem Biophys Res Commun 2001; 285:537-9. [PMID: 11444876 DOI: 10.1006/bbrc.2001.5201] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial beta-oxidation provides much of the fuel requirements of heart and skeletal muscle despite the malonyl-CoA concentration greatly exceeding the IC(50) of carnitine palmitoyl transferase for malonyl-CoA. To try to explore the relationship between inhibition of carnitine palmitoyl transferase I activity and beta-oxidation flux, we measured the flux control coefficient of carnitine palmitoyl transferase I over beta-oxidation carbon flux in suckling rat heart mitochondria. The flux control coefficient was found to be 0.08 +/- 0.05 and 50% of carnitine palmitoyl transferase I activity could be inhibited before beta-oxidation flux was affected. These observations may help to explain the presence of high rates of beta-oxidation despite the high concentration of malonyl-CoA in rat heart; we hypothesize that although not rate-limiting in vitro, carnitine palmitoyl transferase is rate-limiting in vivo because of the high malonyl-CoA concentration in heart and muscle.
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Affiliation(s)
- S Eaton
- Unit of Paediatric Surgery, Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom.
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43
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Ramsay RR, Gandour RD, van der Leij FR. Molecular enzymology of carnitine transfer and transport. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1546:21-43. [PMID: 11257506 DOI: 10.1016/s0167-4838(01)00147-9] [Citation(s) in RCA: 255] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Carnitine (L-3-hydroxy-4-N-trimethylaminobutyric acid) forms esters with a wide range of acyl groups and functions to transport and excrete these groups. It is found in most cells at millimolar levels after uptake via the sodium-dependent carrier, OCTN2. The acylation state of the mobile carnitine pool is linked to that of the limited and compartmentalised coenzyme A pools by the action of the family of carnitine acyltransferases and the mitochondrial membrane transporter, CACT. The genes and sequences of the carriers and the acyltransferases are reviewed along with mutations that affect activity. After summarising the accepted enzymatic background, recent molecular studies on the carnitine acyltransferases are described to provide a picture of the role and function of these freely reversible enzymes. The kinetic and chemical mechanisms are also discussed in relation to the different inhibitors under study for their potential to control diseases of lipid metabolism.
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Affiliation(s)
- R R Ramsay
- Centre for Biomolecular Sciences, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
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44
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Olpin SE, Allen J, Bonham JR, Clark S, Clayton PT, Calvin J, Downing M, Ives K, Jones S, Manning NJ, Pollitt RJ, Standing SJ, Tanner MS. Features of carnitine palmitoyltransferase type I deficiency. J Inherit Metab Dis 2001; 24:35-42. [PMID: 11286380 DOI: 10.1023/a:1005694320063] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Carnitine palmitoyltransferase type I (CPT I) is unique among long-chain fatty acid oxidation enzymes in that there are two tissue-specific isoforms, 'hepatic' and 'muscle', which are encoded by two separate genes. The 'hepatic' isoform is expressed in liver, kidney and fibroblasts and at low levels in the heart, while the other isoform occurs in skeletal muscle and is the predominant form in heart. Reported patients with CPT I deficiency lack activity of the hepatic isoform and present before 30 months of age with hypoketotic hypoglycaemia, hepatomegaly with raised transaminases, seizures and coma. We discuss four new cases in three families showing, variously, renal tubular acidosis, transient hyperlipidaemia and, paradoxically, myopathy with elevated creatinine kinase or cardiac involvement in the neonatal period as additional features that deserve wider recognition.
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Affiliation(s)
- S E Olpin
- Neonatal Screening and Chemical Pathology, Sheffield Children's Hospital, UK
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45
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Cook GA, Edwards TL, Jansen MS, Bahouth SW, Wilcox HG, Park EA. Differential regulation of carnitine palmitoyltransferase-I gene isoforms (CPT-I alpha and CPT-I beta) in the rat heart. J Mol Cell Cardiol 2001; 33:317-29. [PMID: 11162136 DOI: 10.1006/jmcc.2000.1304] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carnitine palmitoyltransferase-I (CPT-I) is a major control point for fatty acid oxidation. Two kinetically different isoforms, CPT-I alpha and CPT-I beta, have been identified. Cardiac ventricular myocytes are the only cells known to express both CPT-I isoforms. In this study, we characterized the differential regulation of CPT-I alpha and CPT-I beta expression in the heart. Expression of the CPT-I alpha gene was very high in the fetal heart and declined following birth. CPT-I beta was also highly expressed in fetal myocytes and remained so throughout development. CPT-I alpha mRNA abundance was increased in both the liver and heart of diabetic or fasted rats, but CPT-I beta mRNA levels were not altered in these states. A high fat diet elevated expression of the CPT-I alpha gene in the liver but not in the heart. The fat content of the diet did not affect the expression of CPT-I beta. Cultures of neonatal rat cardiac myocytes were transfected with luciferase reporter genes driven by CPT-I alpha or CPT-I beta promoters. Two regions of the CPT-I alpha promoter, including an upstream region (-1300/-960) and a region in the proximal promoter (-193/-52) contributed equally to basal expression in cardiac myocytes. Basal transcription of CPT-I alpha was dependent on Sp1 sites and a CCAAT box in the proximal promoter. Our data indicate that the CPT-I beta gene is expressed in a tissue specific manner, but that it is not subject to the same developmental or hormonal controls imposed on CPT-I alpha. In addition some aspects of CPT-I alpha expression are confined to the liver. The data presented here thus suggest that two types of differential regulation of CPT-I genes exist: (a) differential control of CPT-I alpha and CPT-I beta gene expression in the heart and (b) differential regulation of CPT-I alpha expression in the heart and liver.
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Affiliation(s)
- G A Cook
- Department of Pharmacology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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46
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Sanz M, Lopez-Bote CJ, Menoyo D, Bautista JM. Abdominal fat deposition and fatty acid synthesis are lower and beta-oxidation is higher in broiler chickens fed diets containing unsaturated rather than saturated fat. J Nutr 2000; 130:3034-7. [PMID: 11110864 DOI: 10.1093/jn/130.12.3034] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We evaluated the effects of dietary fat type on fat metabolism and deposition in broiler chickens. Birds were fed diets containing either 8 g dietary saturated (beef tallow) or polyunsaturated fat (sunflower oil)/100 g for 32 d. The abdominal fat deposition of chickens fed the sunflower oil-enriched diet was significantly lower than that of chickens fed the tallow-enriched diet (2.63 +/- 0.47 versus 3.03 +/- 0.44 g/100 g live wt.; P = 0.033). The specific activities of heart carnitine palmitoyltransferase I and L-3-hydroxyacyl-CoA dehydrogenase were higher (P < or = 0.03) in chickens fed the sunflower oil-enriched diets, indicating a greater rate of beta-oxidation. Liver fatty acid synthetase activity was lower (P = 0.01) in chickens fed the sunflower oil-enriched diet, suggesting reduced hepatic lipogenesis in this group. Postprandial plasma triglyceride levels were significantly lower (P < 0.05) in birds fed the sunflower oil-enriched diet, indicating a higher rate of dietary lipid clearance from the bloodstream to tissues. In conclusion, the lower fat deposition observed in broilers fed sunflower oil-enriched diets appears to be the net result of an increased rate of lipid catabolism and lower rate of fatty acid synthesis despite higher dietary fat absorption.
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Affiliation(s)
- M Sanz
- Departamento de Producción Animal and Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain
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47
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Martín MA, Gómez MA, Guillén F, Börnstein B, Campos Y, Rubio JC, de la Calzada CS, Arenas J. Myocardial carnitine and carnitine palmitoyltransferase deficiencies in patients with severe heart failure. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1502:330-6. [PMID: 11068176 DOI: 10.1016/s0925-4439(00)00061-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We studied myocardial tissue from 25 cardiac transplant recipients, who had end-stage congestive heart failure (CHF), and from 21 control donor hearts. Concentrations of total carnitine (TC), free carnitine (FC), short-chain acylcarnitines, long-chain acylcarnitines (LCAC) as well as carnitine palmitoyltransferase (CPT) activities were measured in myocardial tissue homogenates and referred to the concentration of non-collagen protein. Compared to controls, the concentrations of TC and FC as well as total CPT activities were significantly lower in patients. LCAC levels and the LCAC to FC ratio values were significantly greater in patients than in controls. While the malonyl-CoA sensitive fraction of CPT, which represents CPT I activity, was similar in patients and controls, the residual CPT activity after inhibition by malonyl-CoA, representing CPT II activity, was significantly reduced in patients compared to controls. Moreover, the activity of CPT in the presence of Triton X-100, which also represents the activity of CPT II, was significantly lower in patients than in controls. Malonyl-CoA concentrations required for half-maximal inhibition of CPT activity were significantly greater in patients than in controls. There was a linear relationship between ejection fraction (EF) values and concentrations of TC, FC, or total CPT activities. Values for LCAC and the LCAC to FC ratio were inversely related to EF values. We conclude that failing heart shows decreased total CPT and CPT II activities and carnitine deficiency that may be related to ventricle function.
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Affiliation(s)
- M A Martín
- Centro de Investigación, Hospital Universitario 12 de Octubre, Madrid, Spain
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48
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Dai J, Zhu H, Shi J, Woldegiorgis G. Identification by mutagenesis of conserved arginine and tryptophan residues in rat liver carnitine palmitoyltransferase I important for catalytic activity. J Biol Chem 2000; 275:22020-4. [PMID: 10801831 DOI: 10.1074/jbc.m002118200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Carnitine palmitoyltransferase I catalyzes the conversion of long-chain acyl-CoA to acylcarnitines in the presence of l-carnitine. To determine the role of the conserved arginine and tryptophan residues on catalytic activity in the liver isoform of carnitine palmitoyltransferase I (L-CPTI), we separately mutated five conserved arginines and two tryptophans to alanine. Substitution of arginine residues 388, 451, and 606 with alanine resulted in loss of 88, 82, and 93% of L-CPTI activity, respectively. Mutants R601A and R655A showed less than 2% of the wild type L-CPTI activity. A change of tryptophan 391 and 452 to alanine resulted in 50 and 93% loss in carnitine palmitoyltransferase activity, respectively. The mutations caused decreases in catalytic efficiency of 80-98%. The residual activity in the mutant L-CPTIs was sensitive to malonyl-CoA inhibition. Mutants R388A, R451A, R606A, W391A, and W452A had no effect on the K(m) values for carnitine or palmitoyl-CoA. However, these mutations decreased the V(max) values for both substrates by 10-40-fold, suggesting that the main effect of the mutations was to decrease the stability of the enzyme-substrate complex. We suggest that conserved arginine and tryptophan residues in L-CPTI contribute to the stabilization of the enzyme-substrate complex by charge neutralization and hydrophobic interactions. The predicted secondary structure of the 100-amino acid residue region of L-CPTI, containing arginines 388 and 451 and tryptophans 391 and 452, consists of four alpha-helices similar to the known three-dimensional structure of the acyl-CoA-binding protein. We predict that this 100-amino acid residue region constitutes the putative palmitoyl-CoA-binding site in L-CPTI.
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Affiliation(s)
- J Dai
- Department of Biochemistry and Molecular Biology, Oregon Graduate Institute of Science and Technology, Beaverton, Oregon 97006-8921, USA
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49
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Wieser T, Deschauer M, Zierz S. Genetics of carnitine palmitoyltransferase II deficiencies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:339-45. [PMID: 10709661 DOI: 10.1007/0-306-46818-2_39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- T Wieser
- Klinik und Poliklinik für Neurologie, Martin-Luther-Universität Halle/Wittenberg, Halle/S., Germany.
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50
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Eaton S, Bartlett K. Tissue specific differences in intramitochondrial control of beta-oxidation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:161-8. [PMID: 10709640 DOI: 10.1007/0-306-46818-2_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- S Eaton
- Sir James Spence Institute of Child Health, Royal Victoria Infirmary, Newcastle-upon-Tyne, U.K.
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