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Narayanan B, Xia C, McAndrew R, Shen AL, Kim JJP. Structural basis for expanded substrate specificities of human long chain acyl-CoA dehydrogenase and related acyl-CoA dehydrogenases. Sci Rep 2024; 14:12976. [PMID: 38839792 PMCID: PMC11153573 DOI: 10.1038/s41598-024-63027-6] [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: 02/23/2024] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Crystal structures of human long-chain acyl-CoA dehydrogenase (LCAD) and the catalytically inactive Glu291Gln mutant, have been determined. These structures suggest that LCAD harbors functions beyond its historically defined role in mitochondrial β-oxidation of long and medium-chain fatty acids. LCAD is a homotetramer containing one FAD per 43 kDa subunit with Glu291 as the catalytic base. The substrate binding cavity of LCAD reveals key differences which makes it specific for longer and branched chain substrates. The presence of Pro132 near the start of the E helix leads to helix unwinding that, together with adjacent smaller residues, permits binding of bulky substrates such as 3α, 7α, l2α-trihydroxy-5β-cholestan-26-oyl-CoA. This structural element is also utilized by ACAD11, a eucaryotic ACAD of unknown function, as well as bacterial ACADs known to metabolize sterol substrates. Sequence comparison suggests that ACAD10, another ACAD of unknown function, may also share this substrate specificity. These results suggest that LCAD, ACAD10, ACAD11 constitute a distinct class of eucaryotic acyl CoA dehydrogenases.
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Affiliation(s)
- Beena Narayanan
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Chuanwu Xia
- Department of Chemistry and Biochemistry, College of Arts and Sciences, University of North Florida, Jacksonville, FL, 32224, USA
| | - Ryan McAndrew
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94740, USA
| | - Anna L Shen
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Jung-Ja P Kim
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
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2
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Narayanan B, Xia C, McAndrew R, Shen AL, Kim JJP. Structural Basis for Expanded Substrate Speci ficities of Human Long Chain Acyl-CoA Dehydrogenase and Related Acyl- CoA Dehydrogenases. RESEARCH SQUARE 2024:rs.3.rs-3980524. [PMID: 38464032 PMCID: PMC10925408 DOI: 10.21203/rs.3.rs-3980524/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Crystal structures of human long-chain acyl-CoA dehydrogenase (LCAD) and the E291Q mutant, have been determined. These structures suggest that LCAD harbors functions beyond its historically defined role in mitochondrial β-oxidation of long and medium-chain fatty acids. LCAD is a homotetramer containing one FAD per 43kDa subunit with Glu291 as the catalytic base. The substrate binding cavity of LCAD reveals key differences which makes it specific for longer and branched chain substrates. The presence of Pro132 near the start of the E helix leads to helix unwinding that, together with adjacent smaller residues, permits binding of bulky substrates such as 3α, 7α, l2α-trihydroxy-5β-cholestan-26-oyl-CoA. This structural element is also utilized by ACAD11, a eucaryotic ACAD of unknown function, as well as bacterial ACADs known to metabolize sterol substrates. Sequence comparison suggests that ACAD10, another ACAD of unknown function, may also share this substrate specificity. These results suggest that LCAD, ACAD10, ACAD11 constitute a distinct class of eucaryotic acyl CoA dehydrogenases.
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3
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Bjune MS, Lawrence-Archer L, Laupsa-Borge J, Sommersten CH, McCann A, Glastad RC, Johnston IG, Kern M, Blüher M, Mellgren G, Dankel SN. Metabolic role of the hepatic valine/3-hydroxyisobutyrate (3-HIB) pathway in fatty liver disease. EBioMedicine 2023; 91:104569. [PMID: 37084480 PMCID: PMC10148099 DOI: 10.1016/j.ebiom.2023.104569] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 03/30/2023] [Accepted: 03/30/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND The valine (branched-chain amino acid) metabolite 3-hydroxyisobutyrate (3-HIB), produced by 3-Hydroxyisobutyryl-CoA Hydrolase (HIBCH), is associated with insulin resistance and type 2 diabetes, but implicated tissues and cellular mechanisms are poorly understood. We hypothesized that HIBCH and 3-HIB regulate hepatic lipid accumulation. METHODS HIBCH mRNA in human liver biopsies ("Liver cohort") and plasma 3-HIB ("CARBFUNC" cohort) were correlated with fatty liver and metabolic markers. Human Huh7 hepatocytes were supplemented with fatty acids (FAs) to induce lipid accumulation. Following HIBCH overexpression, siRNA knockdown, inhibition of PDK4 (a marker of FA β-oxidation) or 3-HIB supplementation, we performed RNA-seq, Western blotting, targeted metabolite analyses and functional assays. FINDINGS We identify a regulatory feedback loop between the valine/3-HIB pathway and PDK4 that shapes hepatic FA metabolism and metabolic health and responds to 3-HIB treatment of hepatocytes. HIBCH overexpression increased 3-HIB release and FA uptake, while knockdown increased cellular respiration and decreased reactive oxygen species (ROS) associated with metabolic shifts via PDK4 upregulation. Treatment with PDK4 inhibitor lowered 3-HIB release and increased FA uptake, while increasing HIBCH mRNA. Implicating this regulatory loop in fatty liver, human cohorts show positive correlations of liver fat with hepatic HIBCH and PDK4 expression (Liver cohort) and plasma 3-HIB (CARBFUNC cohort). Hepatocyte 3-HIB supplementation lowered HIBCH expression and FA uptake and increased cellular respiration and ROS. INTERPRETATION These data implicate the hepatic valine/3-HIB pathway in mechanisms of fatty liver, reflected in increased plasma 3-HIB concentrations, and present possible targets for therapeutic intervention. FUNDING Funding was provided by the Research Council of Norway (263124/F20), the University of Bergen, the Western Norway Health Authorities, Novo Nordisk Scandinavia AS, the Trond Mohn Foundation and the Norwegian Diabetes Association.
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Affiliation(s)
- Mona Synnøve Bjune
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Laurence Lawrence-Archer
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Johnny Laupsa-Borge
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Bevital AS, Bergen, Norway
| | - Cathrine Horn Sommersten
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Mohn Nutrition Research Laboratory, Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | | | | | - Iain George Johnston
- Department of Mathematics, University of Bergen, Bergen, Norway; Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Matthias Kern
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany; Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany; Medical Department III-Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany
| | - Gunnar Mellgren
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Simon N Dankel
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway.
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Qian L, Liu YF, Lu SM, Yang JJ, Miao HJ, He X, Huang H, Zhang JG. Construction of a fatty acid metabolism-related gene signature for predicting prognosis and immune response in breast cancer. Front Genet 2023; 14:1002157. [PMID: 36936412 PMCID: PMC10014556 DOI: 10.3389/fgene.2023.1002157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
Background: Breast cancer has the highest incidence among malignant tumors in women, and its prevalence ranks first in global cancer morbidity. Aim: This study aimed to explore the feasibility of a prognostic model for patients with breast cancer based on the differential expression of genes related to fatty acid metabolism. Methods: The mRNA expression matrix of breast cancer and paracancer tissues was downloaded from The Cancer Genome Atlas database. The differentially expressed genes related to fatty acid metabolism were screened in R language. The TRRUST database was used to predict transcriptional regulators related to hub genes and construct an mRNA-transcription factor interaction network. A consensus clustering approach was used to identify different fatty acid regulatory patterns. In combination with patient survival data, Lasso and multivariate Cox proportional risk regression models were used to establish polygenic prognostic models based on fatty acid metabolism. The median risk score was used to categorize patients into high- and low-risk groups. Kaplan-Meier survival curves were used to analyze the survival differences between both groups. The Cox regression analysis included risk score and clinicopathological factors to determine whether risk score was an independent risk factor. Models based on genes associated with fatty acid metabolism were evaluated using receiver operating characteristic curves. A comparison was made between risk score levels and the fatty acid metabolism-associated genes in different subtypes of breast cancer. The differential gene sets of the Kyoto Encyclopedia of Genes and Genomes for screening high- and low-risk populations were compared using a gene set enrichment analysis. Furthermore, we utilized CIBERSORT to examine the abundance of immune cells in breast cancer in different clustering models. Results: High expression levels of ALDH1A1 and UBE2L6 prevented breast cancer, whereas high RDH16 expression levels increased its risk. Our comprehensive assessment of the association between prognostic risk scoring models and tumor microenvironment characteristics showed significant differences in the abundance of various immune cells between high- and low-risk breast cancer patients. Conclusions: By assessing fatty acid metabolism patterns, we gained a better understanding of the infiltration characteristics of the tumor microenvironment. Our findings are valuable for prognosis prediction and treatment of patients with breast cancer based on their clinicopathological characteristics.
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Affiliation(s)
- Li Qian
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
| | - Yi-Fei Liu
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
| | - Shu-Min Lu
- Department of Oncology, Shanghai Jiaotong University School of Medicine Xinhua Hospital, Shanghai, China
| | - Juan-Juan Yang
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
| | - Hua-Jie Miao
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
| | - Xin He
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
| | - Hua Huang
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
- *Correspondence: Hua Huang, ; Jian-Guo Zhang,
| | - Jian-Guo Zhang
- Department of Pathology, Affiliated Hospital of Nantong University, Nantong, China
- *Correspondence: Hua Huang, ; Jian-Guo Zhang,
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Karunanidhi A, Van’t Land C, Rajasundaram D, Grings M, Vockley J, Mohsen AW. Medium branched chain fatty acids improve the profile of tricarboxylic acid cycle intermediates in mitochondrial fatty acid β-oxidation deficient cells: A comparative study. J Inherit Metab Dis 2022; 45:541-556. [PMID: 35076099 PMCID: PMC9090965 DOI: 10.1002/jimd.12480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 01/09/2022] [Accepted: 01/24/2022] [Indexed: 12/06/2022]
Abstract
Inherited errors of mitochondrial fatty acid β-oxidation (FAO) are life threatening, even with optimum care. FAO is the major source of energy for heart and is critical for skeletal muscles especially during physiologic stress. Clinical trials revealed that triheptanoin (commercially known as Dojolvi; C7G), improved heart function and decreased hypoglycemia in long chain FAO disorders, but other symptoms including rhabdomyolysis persisted, suggesting suboptimal tissue distribution/utilization of heptanoic acid (C7) conjugates and/or rapid liver breakdown. In this study, medium branched chain fatty acids were tested as potential anaplerotic treatments in fibroblasts from patients deficient in very long chain acyl-CoA dehydrogenase (VLCAD), long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD), trifunctional protein (TFP), and carnitine palmitoyltransferase II (CPT II). Cells were cultured to near confluency and treated with C7, 2,6-dimethylheptanoic acid (dMC7), 6-amino-2,4-dimethylheptanoic acid (AdMC7), or 4,8-dimethylnonanoic acid (dMC9) for 72 h and targeted metabolomics performed. The profile of TCA cycle intermediates was improved in cells treated with these branched chain fatty acids compared with C7. Intracellular propionate was higher in AdMC7 treated cells compared with C7 in VLCAD, LCHAD, and TFP deficient cell lines. With AdMC7 treatment, succinate was higher in CPT II and VLCAD deficient cells, compared with C7. Malate and glutamate were consistently higher in AdMC7 treated VLCAD, LCHAD, TFP, and CPT II deficient cells compared with the C7 treatment. The results provide the impetus to further evaluate and consider branched chain fatty acids as viable anaplerotic therapy for fatty acid oxidation disorders and other diseases.
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Affiliation(s)
- Anuradha Karunanidhi
- Department of Pediatrics, School of Medicine, UPMC Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Clinton Van’t Land
- Department of Pediatrics, School of Medicine, UPMC Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Dhivyaa Rajasundaram
- Department of Pediatrics, School of Medicine, UPMC Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Mateus Grings
- Department of Pediatrics, School of Medicine, UPMC Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Jerry Vockley
- Department of Pediatrics, School of Medicine, UPMC Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Al-Walid Mohsen
- Department of Pediatrics, School of Medicine, UPMC Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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D’Annibale OM, Koppes EA, Sethuraman M, Bloom K, Mohsen AW, Vockley J. Characterization of exonic variants of uncertain significance in very long-chain acyl-CoA dehydrogenase identified through newborn screening. J Inherit Metab Dis 2022; 45:529-540. [PMID: 35218577 PMCID: PMC9090957 DOI: 10.1002/jimd.12492] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/20/2022] [Accepted: 02/22/2022] [Indexed: 11/06/2022]
Abstract
Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) is an autosomal recessive disease resulting from mutations in the ACADVL gene and is among the disorders tested for in newborn screening (NBS). Confirmatory sequencing following suspected VLCADD NBS results often identifies variants of uncertain significance (VUS) in the ACADVL gene, leading to uncertainty of diagnosis and providing effective treatment regimen. Currently, ACADVL has >300 VUSs in the ClinVar database that requiring characterization to determine potential pathogenicity. In this study, CRISPR/Cas9 genome editing was used to knock out ACADVL in HEK293T cells, and targeted deletion was confirmed by droplet digital polymerase chain reaction (PCR). No VLCAD protein was detected and an 84% decrease in enzyme activity using the electron transfer flavoprotein fluorescence reduction assay and C21-CoA as substrate was observed compared to control. Plasmids containing control or variant ACADVL coding sequence were transfected into the ACADVL null HEK293T. While transfection of control ACADVL restored VLCAD protein and enzyme activity, cells expressing the VLCAD Val283Ala mutant had 18% VLCAD enzyme activity and reduced protein compared to control. VLCAD Ile420Leu, Gly179Arg, and Gln406Pro produced protein comparable to control but 25%, 4%, and 5% VLCAD enzyme activity, respectively. Leu540Pro and Asp570_Ala572dup had reduced VLCAD protein and 10% and 3% VLCAD enzyme activity, respectively. VLCADD fibroblasts containing the same variations had decreased VLCAD protein and activity comparable to the transfection experiments. Generating ACADVL null HEK293T cell line allowed functional studies to determine pathogenicity of ACADVL exonic variants. This approach can be applied to multiple genes for other disorders identified through NBS.
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Affiliation(s)
- Olivia M. D’Annibale
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261
| | - Erik A. Koppes
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224
| | - Meena Sethuraman
- University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Kaitlyn Bloom
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224
| | - Al-Walid Mohsen
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261
| | - Jerry Vockley
- Division of Genetic and Genomic Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, and UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261
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7
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Goetzman ES, Bharathi SS, Zhang Y, Zhao XJ, Dobrowolski SF, Peasley K, Sims-Lucas S, Monga SP. Impaired mitochondrial medium-chain fatty acid oxidation drives periportal macrovesicular steatosis in sirtuin-5 knockout mice. Sci Rep 2020; 10:18367. [PMID: 33110171 PMCID: PMC7591893 DOI: 10.1038/s41598-020-75615-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/08/2020] [Indexed: 12/14/2022] Open
Abstract
Medium-chain triglycerides (MCT), containing C8-C12 fatty acids, are used to treat several pediatric disorders and are widely consumed as a nutritional supplement. Here, we investigated the role of the sirtuin deacylase Sirt5 in MCT metabolism by feeding Sirt5 knockout mice (Sirt5KO) high-fat diets containing either C8/C10 fatty acids or coconut oil, which is rich in C12, for five weeks. Coconut oil, but not C8/C10 feeding, induced periportal macrovesicular steatosis in Sirt5KO mice. 14C-C12 degradation was significantly reduced in Sirt5KO liver. This decrease was localized to the mitochondrial β-oxidation pathway, as Sirt5KO mice exhibited no change in peroxisomal C12 β-oxidation. Endoplasmic reticulum ω-oxidation, a minor fatty acid degradation pathway known to be stimulated by C12 accumulation, was increased in Sirt5KO liver. Mice lacking another mitochondrial C12 oxidation enzyme, long-chain acyl-CoA dehydrogenase (LCAD), also developed periportal macrovesicular steatosis when fed coconut oil, confirming that defective mitochondrial C12 oxidation is sufficient to induce the steatosis phenotype. Sirt5KO liver exhibited normal LCAD activity but reduced mitochondrial acyl-CoA synthetase activity with C12. These studies reveal a role for Sirt5 in regulating the hepatic response to MCT and may shed light into the pathogenesis of periportal steatosis, a hallmark of human pediatric non-alcoholic fatty liver disease.
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Affiliation(s)
- Eric S Goetzman
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Pittsburgh Liver Research Center, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Sivakama S Bharathi
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Yuxun Zhang
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Xue-Jun Zhao
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Steven F Dobrowolski
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kevin Peasley
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sunder Sims-Lucas
- Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Satdarshan P Monga
- Division of Experimental Pathology, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Pittsburgh Liver Research Center, University of Pittsburgh Medical Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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8
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Beck ME, Zhang Y, Bharathi SS, Kosmider B, Bahmed K, Dahmer MK, Nogee LM, Goetzman ES. The common K333Q polymorphism in long-chain acyl-CoA dehydrogenase (LCAD) reduces enzyme stability and function. Mol Genet Metab 2020; 131:83-89. [PMID: 32389575 PMCID: PMC7606262 DOI: 10.1016/j.ymgme.2020.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 01/19/2023]
Abstract
The fatty acid oxidation enzyme long-chain acyl-CoA dehydrogenase (LCAD) is expressed at high levels in human alveolar type II (ATII) cells in the lung. A common polymorphism causing an amino acid substitution (K333Q) was previously linked to a loss of LCAD antigen in the lung tissue in sudden infant death syndrome. However, the effects of the polymorphism on LCAD function has not been tested. The present work evaluated recombinant LCAD K333Q. Compared to wild-type LCAD protein, LCAD K333Q exhibited significantly reduced enzymatic activity. Molecular modeling suggested that K333 is within interacting distance of the essential FAD cofactor, and the K333Q protein showed a propensity to lose FAD. Exogenous FAD only partially rescued the activity of LCAD K333Q. LCAD K333Q protein was less stable than wild-type when incubated at physiological temperatures, likely explaining the observation of dramatically reduced LCAD antigen in primary ATII cells isolated from individuals homozygous for K333Q. Despite the effect of K333Q on activity, stability, and antigen levels, the frequency of the polymorphism was not increased among infants and children with lung disease.
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Affiliation(s)
- Megan E Beck
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA 15224, United States of America
| | - Yuxun Zhang
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA 15224, United States of America
| | - Sivakama S Bharathi
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA 15224, United States of America
| | - Beata Kosmider
- Department of Physiology, Temple University, Philadelphia, PA 19140, United States of America; Department of Thoracic Medicine and Surgery, Temple University, Philadelphia, PA 19140, United States of America; Center for Inflammation, Translational and Clinical Lung Research, Temple University, Philadelphia, PA 19140, United States of America; Department of Medicine, National Jewish Health, Denver, CO 80206, United States of America
| | - Karim Bahmed
- Department of Thoracic Medicine and Surgery, Temple University, Philadelphia, PA 19140, United States of America; Center for Inflammation, Translational and Clinical Lung Research, Temple University, Philadelphia, PA 19140, United States of America
| | - Mary K Dahmer
- Department of Pediatrics, Division of Critical Care, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Lawrence M Nogee
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States of America
| | - Eric S Goetzman
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA 15224, United States of America.
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9
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Houten SM, Wanders RJA, Ranea-Robles P. Metabolic interactions between peroxisomes and mitochondria with a special focus on acylcarnitine metabolism. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165720. [PMID: 32057943 DOI: 10.1016/j.bbadis.2020.165720] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/03/2020] [Accepted: 02/05/2020] [Indexed: 12/13/2022]
Abstract
Carnitine plays an essential role in mitochondrial fatty acid β-oxidation as a part of a cycle that transfers long-chain fatty acids across the mitochondrial membrane and involves two carnitine palmitoyltransferases (CPT1 and CPT2). Two distinct carnitine acyltransferases, carnitine octanoyltransferase (COT) and carnitine acetyltransferase (CAT), are peroxisomal enzymes, which indicates that carnitine is not only important for mitochondrial, but also for peroxisomal metabolism. It has been demonstrated that after peroxisomal metabolism, specific intermediates can be exported as acylcarnitines for subsequent and final mitochondrial metabolism. There is also evidence that peroxisomes are able to degrade fatty acids that are typically handled by mitochondria possibly after transport as acylcarnitines. Here we review the biochemistry and physiological functions of metabolite exchange between peroxisomes and mitochondria with a special focus on acylcarnitines.
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Affiliation(s)
- Sander M Houten
- Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, Box 1498, New York, NY 10029, USA.
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Pablo Ranea-Robles
- Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, Box 1498, New York, NY 10029, USA
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10
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Zhang Y, Bharathi SS, Beck ME, Goetzman ES. The fatty acid oxidation enzyme long-chain acyl-CoA dehydrogenase can be a source of mitochondrial hydrogen peroxide. Redox Biol 2019; 26:101253. [PMID: 31234015 PMCID: PMC6597861 DOI: 10.1016/j.redox.2019.101253] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/31/2019] [Accepted: 06/10/2019] [Indexed: 11/29/2022] Open
Abstract
Fatty acid oxidation (FAO)-driven H2O2 has been shown to be a major source of oxidative stress in several tissues and disease states. Here, we established that the mitochondrial flavoprotein long-chain acyl-CoA dehydrogenase (LCAD), which catalyzes a key step in mitochondrial FAO, directly produces H2O2in vitro by leaking electrons to oxygen. Kinetic analysis of recombinant human LCAD showed that it produces H2O2 15-fold faster than the related mitochondrial enzyme very long-chain acyl-CoA dehydrogenase (VLCAD), but 50-fold slower than a bona fide peroxisomal acyl-CoA oxidase. The rate of H2O2 formation by human LCAD is slow compared to its activity as a dehydrogenase (about 1%). However, expression of hLCAD in HepG2 cells is sufficient to significantly increase H2O2 in the presence of fatty acids. Liver mitochondria from LCAD−/− mice, but not VLCAD−/− mice, produce significantly less H2O2 during incubation with fatty acids. Finally, we observe highest LCAD expression in human liver, followed by kidney, lung, and pancreas. Based on our data, we propose that the presence of LCAD drives H2O2 formation in response to fatty acids in these tissues.
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Affiliation(s)
- Yuxun Zhang
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - Sivakama S Bharathi
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - Megan E Beck
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - Eric S Goetzman
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.
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11
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An acyl-CoA dehydrogenase microplate activity assay using recombinant porcine electron transfer flavoprotein. Anal Biochem 2019; 581:113332. [PMID: 31194945 DOI: 10.1016/j.ab.2019.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 12/12/2022]
Abstract
Acyl-CoA dehydrogenases (ACADs) play key roles in the mitochondrial catabolism of fatty acids and branched-chain amino acids. All nine characterized ACAD enzymes use electron transfer flavoprotein (ETF) as their redox partner. The gold standard for measuring ACAD activity is the anaerobic ETF fluorescence reduction assay, which follows the decrease of pig ETF fluorescence as it accepts electrons from an ACAD in vitro. Although first described 35 years ago, the assay has not been widely used due to the need to maintain an anaerobic assay environment and to purify ETF from pig liver mitochondria. Here, we present a method for expressing recombinant pig ETF in E coli and purifying it to homogeneity. The recombinant protein is virtually pure after one chromatography step, bears higher intrinsic fluorescence than the native enzyme, and provides enhanced activity in the ETF fluorescence reduction assay. Finally, we present a simplified protocol for removing molecular oxygen that allows adaption of the assay to a 96-well plate format. The availability of recombinant pig ETF and the microplate version of the ACAD activity assay will allow wide application of the assay for both basic research and clinical diagnostics.
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12
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Lipid metabolism in Rhodnius prolixus: Lessons from the genome. Gene 2016; 596:27-44. [PMID: 27697616 DOI: 10.1016/j.gene.2016.09.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/22/2016] [Accepted: 09/28/2016] [Indexed: 01/01/2023]
Abstract
The kissing bug Rhodnius prolixus is both an important vector of Chagas' disease and an interesting model for investigation into the field of physiology, including lipid metabolism. The publication of this insect genome will bring a huge amount of new molecular biology data to be used in future experiments. Although this work represents a promising scenario, a preliminary analysis of the sequence data is necessary to identify and annotate the genes involved in lipid metabolism. Here, we used bioinformatics tools and gene expression analysis to explore genes from different genes families and pathways, including genes for fat breakdown, as lipases and phospholipases, and enzymes from β-oxidation, fatty acid metabolism, and acyl-CoA and glycerolipid synthesis. The R. prolixus genome encodes 31 putative lipase genes, including 21 neutral lipases and 5 acid lipases. The expression profiles of some of these genes were analyzed. We were able to identify nine phospholipase A2 genes. A variety of gene families that participate in fatty acid synthesis and modification were studied, including fatty acid synthase, elongase, desaturase and reductase. Concerning the synthesis of glycerolipids, we found a second isoform of glycerol-3-phosphate acyltransferase that was ubiquitously expressed throughout the organs. Finally, all genes involved in fatty acid β-oxidation were identified, but not a long-chain acyl-CoA dehydrogenase. These results provide fundamental data to be used in future research on insect lipid metabolism and its possible relevance to Chagas' disease transmission.
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13
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Houten SM, Violante S, Ventura FV, Wanders RJA. The Biochemistry and Physiology of Mitochondrial Fatty Acid β-Oxidation and Its Genetic Disorders. Annu Rev Physiol 2015; 78:23-44. [PMID: 26474213 DOI: 10.1146/annurev-physiol-021115-105045] [Citation(s) in RCA: 459] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondrial fatty acid β-oxidation (FAO) is the major pathway for the degradation of fatty acids and is essential for maintaining energy homeostasis in the human body. Fatty acids are a crucial energy source in the postabsorptive and fasted states when glucose supply is limiting. But even when glucose is abundantly available, FAO is a main energy source for the heart, skeletal muscle, and kidney. A series of enzymes, transporters, and other facilitating proteins are involved in FAO. Recessively inherited defects are known for most of the genes encoding these proteins. The clinical presentation of these disorders may include hypoketotic hypoglycemia, (cardio)myopathy, arrhythmia, and rhabdomyolysis and illustrates the importance of FAO during fasting and in hepatic and (cardio)muscular function. In this review, we present the current state of knowledge on the biochemistry and physiological functions of FAO and discuss the pathophysiological processes associated with FAO disorders.
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Affiliation(s)
- Sander M Houten
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029; ,
| | - Sara Violante
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029; ,
| | - Fatima V Ventura
- Metabolism and Genetics Group, Research Institute for Medicines and Pharmaceutical Sciences, iMed.ULisboa, 1649-003 Lisboa, Portugal; .,Department of Biochemistry and Human Biology, Faculty of Pharmacy, University of Lisbon, 1649-003 Lisboa, Portugal
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, University of Amsterdam, 1100 DE Amsterdam, The Netherlands; .,Department of Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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14
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Chai AF, Bulloch EMM, Evans GL, Lott JS, Baker EN, Johnston JM. A covalent adduct of MbtN, an acyl-ACP dehydrogenase from Mycobacterium tuberculosis, reveals an unusual acyl-binding pocket. ACTA ACUST UNITED AC 2015; 71:862-72. [PMID: 25849397 DOI: 10.1107/s1399004715001650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/25/2015] [Indexed: 11/10/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis. Access to iron in host macrophages depends on iron-chelating siderophores called mycobactins and is strongly correlated with Mtb virulence. Here, the crystal structure of an Mtb enzyme involved in mycobactin biosynthesis, MbtN, in complex with its FAD cofactor is presented at 2.30 Å resolution. The polypeptide fold of MbtN conforms to that of the acyl-CoA dehydrogenase (ACAD) family, consistent with its predicted role of introducing a double bond into the acyl chain of mycobactin. Structural comparisons and the presence of an acyl carrier protein, MbtL, in the same gene locus suggest that MbtN acts on an acyl-(acyl carrier protein) rather than an acyl-CoA. A notable feature of the crystal structure is the tubular density projecting from N(5) of FAD. This was interpreted as a covalently bound polyethylene glycol (PEG) fragment and resides in a hydrophobic pocket where the substrate acyl group is likely to bind. The pocket could accommodate an acyl chain of 14-21 C atoms, consistent with the expected length of the mycobactin acyl chain. Supporting this, steady-state kinetics show that MbtN has ACAD activity, preferring acyl chains of at least 16 C atoms. The acyl-binding pocket adopts a different orientation (relative to the FAD) to other structurally characterized ACADs. This difference may be correlated with the apparent ability of MbtN to catalyse the formation of an unusual cis double bond in the mycobactin acyl chain.
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Affiliation(s)
- Ai-Fen Chai
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Esther M M Bulloch
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Genevieve L Evans
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - J Shaun Lott
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Edward N Baker
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jodie M Johnston
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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15
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Acetyl-L-carnitine increases mitochondrial protein acetylation in the aged rat heart. Mech Ageing Dev 2015; 145:39-50. [PMID: 25660059 DOI: 10.1016/j.mad.2015.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 11/24/2014] [Accepted: 01/27/2015] [Indexed: 12/30/2022]
Abstract
Previously we showed that in vivo treatment of elderly Fisher 344 rats with acetylcarnitine abolished the age-associated defect in respiratory chain complex III in interfibrillar mitochondria and improved the functional recovery of the ischemic/reperfused heart. Herein, we explored mitochondrial protein acetylation as a possible mechanism for acetylcarnitine's effect. In vivo treatment of elderly rats with acetylcarnitine restored cardiac acetylcarnitine content and increased mitochondrial protein lysine acetylation and increased the number of lysine-acetylated proteins in cardiac subsarcolemmal and interfibrillar mitochondria. Enzymes of the tricarboxylic acid cycle, mitochondrial β-oxidation, and ATP synthase of the respiratory chain showed the greatest acetylation. Acetylation of isocitrate dehydrogenase, long-chain acyl-CoA dehydrogenase, complex V, and aspartate aminotransferase was accompanied by decreased catalytic activity. Several proteins were found to be acetylated only after treatment with acetylcarnitine, suggesting that exogenous acetylcarnitine served as the acetyl-donor. Two-dimensional fluorescence difference gel electrophoresis analysis revealed that acetylcarnitine treatment also induced changes in mitochondrial protein amount; a two-fold or greater increase/decrease in abundance was observed for thirty one proteins. Collectively, our data provide evidence for the first time that in the aged rat heart in vivo administration of acetylcarnitine provides acetyl groups for protein acetylation and affects the amount of mitochondrial proteins.
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16
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Goetzman ES, Alcorn JF, Bharathi SS, Uppala R, McHugh KJ, Kosmider B, Chen R, Zuo YY, Beck ME, McKinney RW, Skilling H, Suhrie KR, Karunanidhi A, Yeasted R, Otsubo C, Ellis B, Tyurina YY, Kagan VE, Mallampalli RK, Vockley J. Long-chain acyl-CoA dehydrogenase deficiency as a cause of pulmonary surfactant dysfunction. J Biol Chem 2014; 289:10668-10679. [PMID: 24591516 DOI: 10.1074/jbc.m113.540260] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Long-chain acyl-CoA dehydrogenase (LCAD) is a mitochondrial fatty acid oxidation enzyme whose expression in humans is low or absent in organs known to utilize fatty acids for energy such as heart, muscle, and liver. This study demonstrates localization of LCAD to human alveolar type II pneumocytes, which synthesize and secrete pulmonary surfactant. The physiological role of LCAD and the fatty acid oxidation pathway in lung was subsequently studied using LCAD knock-out mice. Lung fatty acid oxidation was reduced in LCAD(-/-) mice. LCAD(-/-) mice demonstrated reduced pulmonary compliance, but histological examination of lung tissue revealed no obvious signs of inflammation or pathology. The changes in lung mechanics were found to be due to pulmonary surfactant dysfunction. Large aggregate surfactant isolated from LCAD(-/-) mouse lavage fluid had significantly reduced phospholipid content as well as alterations in the acyl chain composition of phosphatidylcholine and phosphatidylglycerol. LCAD(-/-) surfactant demonstrated functional abnormalities when subjected to dynamic compression-expansion cycling on a constrained drop surfactometer. Serum albumin, which has been shown to degrade and inactivate pulmonary surfactant, was significantly increased in LCAD(-/-) lavage fluid, suggesting increased epithelial permeability. Finally, we identified two cases of sudden unexplained infant death where no lung LCAD antigen was detectable. Both infants were homozygous for an amino acid changing polymorphism (K333Q). These findings for the first time identify the fatty acid oxidation pathway and LCAD in particular as factors contributing to the pathophysiology of pulmonary disease.
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Affiliation(s)
- Eric S Goetzman
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
| | - John F Alcorn
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Sivakama S Bharathi
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Radha Uppala
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Kevin J McHugh
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Beata Kosmider
- Department of Medicine, National Jewish Health, Denver, Colorado 80206
| | - Rimei Chen
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Megan E Beck
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Richard W McKinney
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Helen Skilling
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Kristen R Suhrie
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Anuradha Karunanidhi
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Renita Yeasted
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Chikara Otsubo
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224
| | - Bryon Ellis
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Yulia Y Tyurina
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Valerian E Kagan
- Center for Free Radical and Antioxidant Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Rama K Mallampalli
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, Pennsylvania 15213; Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15213
| | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15224; Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
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17
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Jang GW, Lee KT, Park JE, Kim H, Kim TH, Choi BH, Kim MJ, Lim D. Gene Expression Profiling in Hepatic Tissue of two Pig Breeds. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2012. [DOI: 10.5187/jast.2012.54.6.383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Houten SM, Wanders RJA. A general introduction to the biochemistry of mitochondrial fatty acid β-oxidation. J Inherit Metab Dis 2010; 33:469-77. [PMID: 20195903 PMCID: PMC2950079 DOI: 10.1007/s10545-010-9061-2] [Citation(s) in RCA: 600] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 10/14/2009] [Accepted: 01/28/2010] [Indexed: 12/30/2022]
Abstract
Over the years, the mitochondrial fatty acid β-oxidation (FAO) pathway has been characterised at the biochemical level as well as the molecular biological level. FAO plays a pivotal role in energy homoeostasis, but it competes with glucose as the primary oxidative substrate. The mechanisms behind this so-called glucose-fatty acid cycle operate at the hormonal, transcriptional and biochemical levels. Inherited defects for most of the FAO enzymes have been identified and characterised and are currently included in neonatal screening programmes. Symptoms range from hypoketotic hypoglycaemia to skeletal and cardiac myopathies. The pathophysiology of these diseases is still not completely understood, hampering optimal treatment. Studies of patients and mouse models will contribute to our understanding of the pathogenesis and will ultimately lead to better treatment.
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Affiliation(s)
- Sander Michel Houten
- Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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19
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Maher AC, Mohsen AW, Vockley J, Tarnopolsky MA. Low expression of long-chain acyl-CoA dehydrogenase in human skeletal muscle. Mol Genet Metab 2010; 100:163-7. [PMID: 20363655 PMCID: PMC3974577 DOI: 10.1016/j.ymgme.2010.03.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 03/13/2010] [Accepted: 03/14/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Long-chain acyl-CoA dehydrogenase (LCAD) is a mitochondrial flavoenzyme thought to be one of the major enzymes responsible for the first step of long-chain fatty acid (LCFA) beta-oxidation. Surprisingly, recent studies have shown LCAD is hardly detectable in human tissues such as liver and heart. Skeletal muscle is the largest organ in the body in terms of mass, and accounts for the majority of LCFA oxidation, especially during exercise. The purpose of this study was to investigate the expression levels of LCAD in human skeletal muscle. METHODS Muscle biopsies were obtained from the vastus lateralis of healthy athletic men and women, and examined for mRNA abundance, protein content, and enzyme activity of LCAD. We compared LCAD content with that of very-long chain acyl-CoA dehydrogenase (VLCAD) and medium chain acyl-CoA dehydrogenase (MCAD); two mitochondrial beta-oxidation enzymes that have overlapping chain-length specificity to that of LCAD. LCAD protein content and enzyme activity were also examined in enriched mitochondrial protein fractions. As controls, LCAD presence in skeletal muscle was compared to human heart, liver, and mouse skeletal muscle. RESULTS The mRNA presence of LCAD in human skeletal muscle is significantly less than VLCAD and MCAD (0.08+/-0.01 vs 7.3+/-0.5 vs 2.4+/-0.2 respectively, P<or=0.0001). LCAD protein was undetectable in human muscle homogenates, and coordinately LCAD enzyme activity was undetectable in enriched mitochondrial samples. CONCLUSION LCAD is minimally expressed in human skeletal muscle and likely does not play a significant role in LCFA oxidation.
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Affiliation(s)
- Amy C. Maher
- Department of Medical Science, McMaster University, Hamilton, Ontario, Canada
| | - Al-Walid Mohsen
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15213, USA
| | - Mark A. Tarnopolsky
- Department of Pediatrics and Medicine, McMaster University, Hamilton, Ontario, Canada
- Correspondence to: M.A. Tarnopolsky, Department of Pediatrics and Medicine, Division of Neurology, Room 2H26, McMaster University Medical Center, 1200 Main Street West, Hamilton, Ontario, Canada L8S 3Z5. Fax: +1 905 577 8380
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20
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Sobhi HF, Minkler PE, Hoppel CL. Synthesis and characterization of cis-4-decenoyl-CoA, 3-phenylpropionyl-CoA, and 2,6-dimethylheptanoyl-CoA. Anal Biochem 2010; 401:114-24. [PMID: 20184857 DOI: 10.1016/j.ab.2010.02.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 02/04/2010] [Accepted: 02/19/2010] [Indexed: 11/26/2022]
Abstract
The measurement of acyl-CoA dehydrogenase activities is an essential part of the investigation of patients with suspected defects in fatty acid oxidation. Multiple methods are available for the synthesis of the substrates used for measuring acyl-CoA dehydrogenase activities; however, the yields are low and the products are used without purification. In addition, the reported characterization of acyl-CoAs focuses on the CoA moiety, not on the acyl group. Here we describe the synthesis of three medium-chain acyl-CoAs from mixed anhydrides of the fatty acids using an aqueous-organic solvent mixture optimized to obtain the highest yield. First, cis-4-decenoic acid and 2,6-dimethylheptanoic acid were prepared (3-phenylpropionic acid is commercially available). These were characterized by gas chromatography/mass spectrometry (GC/MS), (1)H nuclear magnetic resonance (NMR), and (13)C NMR. Then cis-4-decenoyl-CoA, 3-phenylpropionyl-CoA, and 2,6-dimethylheptanoyl-CoA were synthesized. These were then purified by ion exchange solid-phase extraction using 2-(2-pyridyl)ethyl-functionalized silica gel, followed by reversed-phase semipreparative high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The purified acyl-CoAs were characterized by analytical HPLC-UV followed by data-dependent tandem mass spectrometry (MS/MS) analysis on the largest responding MS mass (HPLC-UV-MS-MS/MS) and (13)C NMR. The yields of the purified acyl-CoAs were between 75% and 78% based on coenzyme A trilithium salt (CoASH). Acyl-CoA dehydrogenase activities were measured in rat skeletal muscle mitochondria using, as substrates, the synthesized cis-4-decenoyl-CoA, 3-phenylpropionyl-CoA, and 2,6-dimethylheptanoyl-CoA. These results were compared with the results using our standard substrates butyryl-CoA, octanoyl-CoA, and palmitoyl-CoA.
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Affiliation(s)
- Hany F Sobhi
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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21
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Chegary M, Brinke HT, Ruiter JPN, Wijburg FA, Stoll MSK, Minkler PE, van Weeghel M, Schulz H, Hoppel CL, Wanders RJA, Houten SM. Mitochondrial long chain fatty acid beta-oxidation in man and mouse. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:806-15. [PMID: 19465148 DOI: 10.1016/j.bbalip.2009.05.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 04/28/2009] [Accepted: 05/18/2009] [Indexed: 10/20/2022]
Abstract
Several mouse models for mitochondrial fatty acid beta-oxidation (FAO) defects have been developed. So far, these models have contributed little to our current understanding of the pathophysiology. The objective of this study was to explore differences between murine and human FAO. Using a combination of analytical, biochemical and molecular methods, we compared fibroblasts of long chain acyl-CoA dehydrogenase knockout (LCAD(-/-)), very long chain acyl-CoA dehydrogenase knockout (VLCAD(-/-)) and wild type mice with fibroblasts of VLCAD-deficient patients and human controls. We show that in mice, LCAD and VLCAD have overlapping and distinct roles in FAO. The absence of VLCAD is apparently fully compensated, whereas LCAD deficiency is not. LCAD plays an essential role in the oxidation of unsaturated fatty acids such as oleic acid, but seems redundant in the oxidation of saturated fatty acids. In strong contrast, LCAD is neither detectable at the mRNA level nor at the protein level in men, making VLCAD indispensable in FAO. Our findings open new avenues to employ the existing mouse models to study the pathophysiology of human FAO defects.
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Affiliation(s)
- Malika Chegary
- Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, The Netherlands
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22
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Oey NA, Ruiter JPN, Ijlst L, Attie-Bitach T, Vekemans M, Wanders RJA, Wijburg FA. Acyl-CoA dehydrogenase 9 (ACAD 9) is the long-chain acyl-CoA dehydrogenase in human embryonic and fetal brain. Biochem Biophys Res Commun 2006; 346:33-7. [PMID: 16750164 DOI: 10.1016/j.bbrc.2006.05.088] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Accepted: 05/08/2006] [Indexed: 11/20/2022]
Abstract
We recently reported the expression and activity of several fatty acid oxidation enzymes in human embryonic and fetal tissues including brain and spinal cord. Liver and heart showed expression of both very long-chain acyl-CoA dehydrogenase (VLCAD) and long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) mRNA. However, while mRNA expression of LCHAD could be clearly detected in the retina and spinal cord, expression of VLCAD mRNA was low to undetectable in these tissues. Nevertheless, abundant acyl-CoA dehydrogenase (ACAD) activity was detected with palmitoyl-CoA as substrate in fetal central nervous tissue. These conflicting data suggested the presence of a different long-chain ACAD in human embryonic and fetal brain. In this study, using in situ hybridization as well as enzymatic studies, we identified acyl-CoA dehydrogenase 9 (ACAD 9) as the long-chain ACAD in human embryonic and fetal central nervous tissue. Until now, no clinical signs and symptoms of central nervous system involvement have been reported in VLCAD deficiency. A novel long-chain FAO defect, i.e., ACAD 9 deficiency with only central nervous system involvement, could, if not lethal during intra uterine development, easily escape proper diagnosis, since probably no classical signs and symptoms of FAO deficiency will be observed. Screening for ACAD 9 deficiency in patients with undefined neurological symptoms and/or impairment in neurological development of unknown origin is necessary to establish if ACAD 9 deficiency exists as a separate disease entity.
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Affiliation(s)
- N A Oey
- Department of Paediatrics, Laboratory for Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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23
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van Vlies N, Tian L, Overmars H, Bootsma A, Kulik W, Wanders R, Wood P, Vaz F. Characterization of carnitine and fatty acid metabolism in the long-chain acyl-CoA dehydrogenase-deficient mouse. Biochem J 2005; 387:185-93. [PMID: 15535801 PMCID: PMC1134946 DOI: 10.1042/bj20041489] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In the present paper, we describe a novel method which enables the analysis of tissue acylcarnitines and carnitine biosynthesis intermediates in the same sample. This method was used to investigate the carnitine and fatty acid metabolism in wild-type and LCAD-/- (long-chain acyl-CoA dehydrogenase-deficient) mice. In agreement with previous results in plasma and bile, we found accumulation of the characteristic C14:1-acylcarnitine in all investigated tissues from LCAD-/- mice. Surprisingly, quantitatively relevant levels of 3-hydroxyacylcarnitines were found to be present in heart, muscle and brain in wild-type mice, suggesting that, in these tissues, long-chain 3-hydroxyacyl-CoA dehydrogenase is rate-limiting for mitochondrial beta-oxidation. The 3-hydroxyacylcarnitines were absent in LCAD-/- tissues, indicating that, in this situation, the beta-oxidation flux is limited by the LCAD deficiency. A profound deficiency of acetylcarnitine was observed in LCAD-/- hearts, which most likely corresponds with low cardiac levels of acetyl-CoA. Since there was no carnitine deficiency and only a marginal elevation of potentially cardiotoxic acylcarnitines, we conclude from these data that the cardiomyopathy in the LCAD-/- mouse is caused primarily by a severe energy deficiency in the heart, stressing the important role of LCAD in cardiac fatty acid metabolism in the mouse.
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Affiliation(s)
- Naomi van Vlies
- *Departments of Clinical Chemistry and Pediatrics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
| | - Liqun Tian
- †Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0024, U.S.A
| | - Henk Overmars
- *Departments of Clinical Chemistry and Pediatrics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
| | - Albert H. Bootsma
- *Departments of Clinical Chemistry and Pediatrics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
| | - Willem Kulik
- *Departments of Clinical Chemistry and Pediatrics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
| | - Ronald J. A. Wanders
- *Departments of Clinical Chemistry and Pediatrics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
| | - Philip A. Wood
- †Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0024, U.S.A
| | - Frédéric M. Vaz
- *Departments of Clinical Chemistry and Pediatrics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
- To whom correspondence should be addressed (email )
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24
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Ensenauer R, He M, Willard JM, Goetzman ES, Corydon TJ, Vandahl BB, Mohsen AW, Isaya G, Vockley J. Human acyl-CoA dehydrogenase-9 plays a novel role in the mitochondrial beta-oxidation of unsaturated fatty acids. J Biol Chem 2005; 280:32309-16. [PMID: 16020546 DOI: 10.1074/jbc.m504460200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Unsaturated fatty acids play an important role in the prevention of human diseases such as diabetes, obesity, cancer, and neurodegeneration. However, their oxidation in vivo by acyl-CoA dehydrogenases (ACADs) that catalyze the first step of each cycle of mitochondrial fatty acid beta-oxidation is not entirely understood. Recently, a novel ACAD (ACAD-9) of unknown function that is highly homologous to human very-long-chain acyl-CoA dehydrogenase was identified by large-scale random sequencing. To characterize its enzymatic role, we have expressed ACAD-9 in Escherichia coli, purified it, and determined its pattern of substrate utilization. The N terminus of the mature form of the enzyme was identified by in vitro mitochondrial import studies of precursor protein. A 37-amino acid leader peptide was cleaved sequentially by two mitochondrial peptidases to yield a predicted molecular mass of 65 kDa for the mature subunit. Submitochondrial fractionation studies found native ACAD-9 to be associated with the mitochondrial membrane. Gel filtration analysis indicated that, like very-long-chain acyl-CoA dehydrogenase, ACAD-9 is a dimer, in contrast to the other known ACADs, which are tetramers. Purified mature ACAD-9 had maximal activity with long-chain unsaturated acyl-CoAs as substrates (C16:1-, C18:1-, C18:2-, C22:6-CoA). These results suggest a previously unrecognized role for ACAD-9 in the mitochondrial beta-oxidation of long-chain unsaturated fatty acids. Because of the substrate specificity and abundance of ACAD-9 in brain, we speculate that it may play a role in the turnover of lipid membrane unsaturated fatty acids that are essential for membrane integrity and structure.
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MESH Headings
- Acyl-CoA Dehydrogenase, Long-Chain/metabolism
- Acyl-CoA Dehydrogenase, Long-Chain/physiology
- Amino Acid Sequence
- Animals
- Brain/metabolism
- Cell Membrane/metabolism
- Chromatography, Gel
- Chromatography, High Pressure Liquid
- Cloning, Molecular
- Escherichia coli/metabolism
- Fatty Acids/metabolism
- Humans
- Kinetics
- Lipid Metabolism
- Lipids/chemistry
- Mitochondria/metabolism
- Models, Molecular
- Molecular Sequence Data
- Muscles/metabolism
- Mutagenesis
- Oxygen/metabolism
- Peptides/chemistry
- Polymerase Chain Reaction
- Protein Conformation
- Protein Structure, Tertiary
- Recombinant Proteins/chemistry
- Sequence Analysis, DNA
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Substrate Specificity
- Transcription, Genetic
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Affiliation(s)
- Regina Ensenauer
- Department of Medical Genetics, Pediatric and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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25
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Gloerich J, van Vlies N, Jansen GA, Denis S, Ruiter JPN, van Werkhoven MA, Duran M, Vaz FM, Wanders RJA, Ferdinandusse S. A phytol-enriched diet induces changes in fatty acid metabolism in mice both via PPARalpha-dependent and -independent pathways. J Lipid Res 2005; 46:716-26. [PMID: 15654129 DOI: 10.1194/jlr.m400337-jlr200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Branched-chain fatty acids (such as phytanic and pristanic acid) are ligands for the nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in vitro. To investigate the effects of these physiological compounds in vivo, wild-type and PPARalpha-deficient (PPARalpha-/-) mice were fed a phytol-enriched diet. This resulted in increased plasma and liver levels of the phytol metabolites phytanic and pristanic acid. In wild-type mice, plasma fatty acid levels decreased after phytol feeding, whereas in PPARalpha-/- mice, the already elevated fatty acid levels increased. In addition, PPARalpha-/- mice were found to be carnitine deficient in both plasma and liver. Dietary phytol increased liver free carnitine in wild-type animals but not in PPARalpha-/- mice. Investigation of carnitine biosynthesis revealed that PPARalpha is likely involved in the regulation of carnitine homeostasis. Furthermore, phytol feeding resulted in a PPARalpha-dependent induction of various peroxisomal and mitochondrial beta-oxidation enzymes. In addition, a PPARalpha-independent induction of catalase, phytanoyl-CoA hydroxylase, carnitine octanoyltransferase, peroxisomal 3-ketoacyl-CoA thiolase, and straight-chain acyl-CoA oxidase was observed. In conclusion, branched-chain fatty acids are physiologically relevant ligands of PPARalpha in mice. These findings are especially relevant for disorders in which branched-chain fatty acids accumulate, such as Refsum disease and peroxisome biogenesis disorders.
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Affiliation(s)
- J Gloerich
- University of Amsterdam, Academic Medical Center, Departments of Clinical Chemistry and Pediatrics, Laboratory for Genetic Metabolic Diseases, 1100 DE Amsterdam, The Netherlands
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26
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Clark-Taylor T, Clark-Taylor BE. Is autism a disorder of fatty acid metabolism? Possible dysfunction of mitochondrial beta-oxidation by long chain acyl-CoA dehydrogenase. Med Hypotheses 2004; 62:970-5. [PMID: 15142659 DOI: 10.1016/j.mehy.2004.01.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Accepted: 01/26/2004] [Indexed: 10/26/2022]
Abstract
Long chain acyl-CoA dehydrogenase (LCAD) has recently been shown to be the mitochondrial enzyme responsible for the beta-oxidation of branched chain and unsaturated fatty acids [Biochim. Biophys. Acta 1393 (1998) 35; Biochim. Biophys. Acta 1485 (2000) 121]. Whilst disorders of short, medium and very long chain acyl dehydrogenases are known, there is no known disorder of LCAD deficiency in humans. Experimental LCAD deficiency in mice shows an acyl-carnitine profile with prominent elevations of unsaturated fatty acid metabolites C14:1 and C14:2 [Hum. Mol. Genet. 10 (2001) 2069]. A child with autism whose acyl-carnitine profile also shows these abnormalities is presented, and it is hypothesized that the child may have LCAD deficiency. Additional metabolic abnormalities seen in this patient include alterations of TCA energy production, ammonia detoxification, reduced synthesis of omega-3 DHA, and abnormal cholesterol metabolism. These metabolic changes are also seen as secondary abnormalities in dysfunction of fatty acid beta-oxidation, and have also been reported in autism. It is hypothesized that LCAD deficiency may be a cause of autism. Similarities between metabolic disturbances in autism, and those of disorders of fatty acid beta-oxidation are discussed.
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27
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Abstract
Mitochondrial beta-oxidation is a complex pathway involving, in the case of saturated straight chain fatty acids of even carbon number, at least 16 proteins which are organized into two functional subdomains; one associated with the inner face of the inner mitochondrial membrane and the other in the matrix. Overall, the pathway is subject to intramitochondrial control at multiple sites. However, at least in the liver, carnitine palmitoyl transferase I exerts approximately 80% of control over pathway flux under normal conditions. Clearly, when one or more enzyme activities are attenuated because of a mutation, the major site of flux control will change.
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Affiliation(s)
- Kim Bartlett
- Department of Child Health, Sir James Spence Institute of Child Health, University of Newcastle upon Tyne, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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28
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Heales SJR, Gegg ME, Clark JB. Oxidative phosphorylation: structure, function, and intermediary metabolism. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2003; 53:25-56. [PMID: 12512336 DOI: 10.1016/s0074-7742(02)53003-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Simon J R Heales
- Department of Neurochemistry, Clinical Biochemistry (Neurometabolic Unit), Institute of Neurology and National Hospital, London, WC1N 3BG, United Kingdom
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29
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Tran TN, Christophersen BO. Partitioning of polyunsaturated fatty acid oxidation between mitochondria and peroxisomes in isolated rat hepatocytes studied by HPLC separation of oxidation products. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1583:195-204. [PMID: 12117563 DOI: 10.1016/s1388-1981(02)00213-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The extent of mitochondrial and peroxisomal contribution to beta-oxidation of 18-, 20- and 24-carbon n-3 and n-6 polyunsaturated fatty acids (PUFAs) in intact rat hepatocytes is not fully clear. In this study, we analyzed radiolabeled acid soluble oxidation products by HPLC to identify mitochondrial and peroxisomal oxidation of 24:5n-3, 18- and 20-carbon n-3 and n-6 PUFAs. Mitochondrial fatty acid oxidation produced high levels of ketone bodies, tricarboxylic acid cycle intermediates and CO(2), while peroxisomal beta-oxidation released acetate. Inhibition of mitochondrial fatty acid oxidation with 2-tetradecylglycidic acid (TDGA), high amounts of [14C]acetate from oxidation of 24:5n-3, 18- and 20-carbon PUFAs were observed. In the absence of TDGA, high amounts of [14C]-labeled mitochondrial oxidation products were formed from oxidation of 24:5n-3, 18- and 20-carbon PUFAs. With 18:1n-9, high amounts of mitochondrial oxidation products were formed in the absence of TDGA, and TDGA strongly suppressed the oxidation of this fatty acid. Data of this study indicated that a shift in the partitioning from mitochondrial to peroxisomal oxidation differed for each individual fatty acid and is a specific property of 24:5n-3, 18- and 20-carbon n-3 and n-6 PUFAs.[14C]22:6n-3 was detected with [3-14C]24:5n-3, but not with [1-14C]24:5n-3 as the substrate, while [14C]16:0 was detected with [1-14C]24:5n-3, but not with [3-14C]24:5n-3 as the substrate. Furthermore, the amounts of 14CO(2) were similar when cells were incubated with [3-14C]24:5n-3 versus [1-14C]24:5n-3. These findings indicated that the proportion of 24:5n-3 oxidized in mitochondria was high, and that 24:5n-3 and 24:6n-3 were mostly beta-oxidized only one cycle in peroxisomes.
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Affiliation(s)
- Thien N Tran
- Institute of Clinical Biochemistry, Rikshospitalet University Hospital, University of Oslo, NO-0027 Oslo, Norway.
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30
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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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31
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Bremer J. The biochemistry of hypo- and hyperlipidemic fatty acid derivatives: metabolism and metabolic effects. Prog Lipid Res 2001; 40:231-68. [PMID: 11412891 DOI: 10.1016/s0163-7827(01)00004-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A selection of amphipatic hyper- and hypolipidemic fatty acid derivatives (fibrates, thia- and branched chain fatty acids) are reviewed. They are probably all ligands for the peroxisome proliferation activation receptor (PPARalpha) which has a low selectivity for its ligands. These compounds give hyper- or hypolipidemic responses depending on their ability to inhibit or stimulate mitochondrial fatty acid oxidation in the liver. The hypolipidemic response is explained by the following metabolic effects: Lipoprotein lipase is induced in liver where it is normally not expressed. Apolipoprotein CIII is downregulated. These two effects in liver lead to a facilitated (re)uptake of chylomicrons and VLDL, thus creating a direct transport of fatty acids from the gut to the liver. Fatty acid metabolizing enzymes in the liver (CPT-I and II, peroxisomal and mitochondrial beta-oxidation enzymes, enzymes of ketogenesis, and omega-oxidation enzymes) are induced and create an increased capacity for fatty acid oxidation. The increased oxidation of fatty acids "drains" fatty acids from the body, reduces VLDL formation, and ultimately explains the antiadiposity and improved insulin sensitivity observed after administration of peroxisome proliferators.
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Affiliation(s)
- J Bremer
- Institute of Medical Biochemistry, University of Oslo, Pb 1112 Blindern, 0317, Oslo, Norway
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32
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Ferdinandusse S, Denis S, IJlst L, Dacremont G, Waterham HR, Wanders RJ. Subcellular localization and physiological role of α-methylacyl-CoA racemase. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31983-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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33
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Lea W, Abbas AS, Sprecher H, Vockley J, Schulz H. Long-chain acyl-CoA dehydrogenase is a key enzyme in the mitochondrial beta-oxidation of unsaturated fatty acids. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1485:121-8. [PMID: 10832093 DOI: 10.1016/s1388-1981(00)00034-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first reaction of mitochondrial beta-oxidation, which is catalyzed by acyl-CoA dehydrogenases, was studied with unsaturated fatty acids that have a double bond either at the 4,5 or 5,6 position. The CoA thioesters of docosahexaenoic acid, arachidonic acid, 4,7,10-cis-hexadecatrienoic acid, 5-cis-tetradecenoic acid, and 4-cis-decenoic acid were effectively dehydrogenated by both rat and human long-chain acyl-CoA dehydrogenases (LCAD), whereas they were poor substrates of very long-chain acyl-CoA dehydrogenases (VLCAD). VLCAD, however, was active with CoA derivatives of long-chain saturated fatty acids or unsaturated fatty acids that have double bonds further removed from the thioester function. Although bovine LCAD effectively dehydrogenated 5-cis-tetradecenoyl-CoA (14:1) and 4,7,10-cis-hexadecatrienoyl-CoA, it was nearly inactive toward the other unsaturated substrates. The catalytic efficiency of rat VLCAD with 14:1 as substrate was only 4% of the efficiency determined with tetradecanoyl-CoA, whereas LCAD acted equally well on both substrates. The conclusion of this study is that LCAD serves an important, if not essential function in the beta-oxidation of unsaturated fatty acids.
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Affiliation(s)
- W Lea
- Department of Chemistry, City College of the City University of New York, NY 10031, USA
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34
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Ferdinandusse S, Mulders J, IJlst L, Denis S, Dacremont G, Waterham HR, Wanders RJ. Molecular cloning and expression of human carnitine octanoyltransferase: evidence for its role in the peroxisomal beta-oxidation of branched-chain fatty acids. Biochem Biophys Res Commun 1999; 263:213-8. [PMID: 10486279 DOI: 10.1006/bbrc.1999.1340] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To study the putative role of human carnitine octanoyltransferase (COT) in the beta-oxidation of branched-chain fatty acids, we identified and cloned the cDNA encoding human COT and expressed it in the yeast Saccharomyces cerevisiae. Enzyme activity measurements showed that COT efficiently converts one of the end products of the peroxisomal beta-oxidation of pristanic acid, 4, 8-dimethylnonanoyl-CoA, to its corresponding carnitine ester. Production of the carnitine ester of this branched/medium-chain acyl-CoA within the peroxisome is required for its transport to the mitochondrion where further beta-oxidation occurs. In contrast, 4, 8-dimethylnonanoyl-CoA is not a substrate for carnitine acetyltransferase, another acyltransferase localized in peroxisomes, which catalyzes the formation of carnitine esters of the other products of pristanic acid beta-oxidation, namely acetyl-CoA and propionyl-CoA. Our results shed new light on the function of COT in fatty acid metabolism and point to a crucial role of COT in the beta-oxidation of branched-chain fatty acids.
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Affiliation(s)
- S Ferdinandusse
- Departments of Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, Amsterdam, 1100 DE, The Netherlands
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35
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Wanders RJ, Vreken P, den Boer ME, Wijburg FA, van Gennip AH, IJlst L. Disorders of mitochondrial fatty acyl-CoA beta-oxidation. J Inherit Metab Dis 1999; 22:442-87. [PMID: 10407780 DOI: 10.1023/a:1005504223140] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In recent years tremendous progress has been made with respect to the enzymology of the mitochondrial fatty acid beta-oxidation machinery and defects therein. Firstly, a number of new mitochondrial beta-oxidation enzymes have been identified, including very-long-chain acyl-CoA dehydrogenase (VLCAD) and mitochondrial trifunctional protein (MTP). Secondly, the introduction of tandem MS for the analysis of plasma acylcarnitines has greatly facilitated the identification of patients with a defect in fatty acid oxidation (FAO). These two developments explain why the number of defined FAO disorders has increased dramatically, making FAO disorders the most rapidly growing group of inborn errors of metabolism. In this review we describe the current state of knowledge of the enzymes involved in the mitochondrial oxidation of straight-chain, branched-chain and (poly)unsaturated fatty acyl-CoAs as well as disorders of fatty acid oxidation. The laboratory diagnosis of these disorders is described, with particular emphasis on the methods used to identify the underlying enzyme defect and the molecular mutations. In addition, a simple flowchart is presented as a guide to the identification of mitochondrial FAO-disorders. Finally, treatment strategies are discussed briefly.
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Affiliation(s)
- R J Wanders
- Academic Medical Center, University of Amsterdam, The Netherlands.
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