1
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Du W, Zhang L, Brett-Morris A, Aguila B, Kerner J, Hoppel CL, Puchowicz M, Serra D, Herrero L, Rini BI, Campbell S, Welford SM. HIF drives lipid deposition and cancer in ccRCC via repression of fatty acid metabolism. Nat Commun 2017; 8:1769. [PMID: 29176561 PMCID: PMC5701259 DOI: 10.1038/s41467-017-01965-8] [Citation(s) in RCA: 264] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 10/30/2017] [Indexed: 01/17/2023] Open
Abstract
Clear cell renal cell carcinoma (ccRCC) is histologically defined by its lipid and glycogen-rich cytoplasmic deposits. Alterations in the VHL tumor suppressor stabilizing the hypoxia-inducible factors (HIFs) are the most prevalent molecular features of clear cell tumors. The significance of lipid deposition remains undefined. We describe the mechanism of lipid deposition in ccRCC by identifying the rate-limiting component of mitochondrial fatty acid transport, carnitine palmitoyltransferase 1A (CPT1A), as a direct HIF target gene. CPT1A is repressed by HIF1 and HIF2, reducing fatty acid transport into the mitochondria, and forcing fatty acids to lipid droplets for storage. Droplet formation occurs independent of lipid source, but only when CPT1A is repressed. Functionally, repression of CPT1A is critical for tumor formation, as elevated CPT1A expression limits tumor growth. In human tumors, CPT1A expression and activity are decreased versus normal kidney; and poor patient outcome associates with lower expression of CPT1A in tumors in TCGA. Together, our studies identify HIF control of fatty acid metabolism as essential for ccRCC tumorigenesis. Clear cell renal cancers (ccRCC) display elevated intracellular lipid storage. Here the authors show that such lipid accumulation is due to the repression of carnitine palmitoyltransferase 1A (CPT1A) enzyme that impairs fatty acid (FA) transport into the mitochondrion resulting in reduced FA beta oxidation.
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Affiliation(s)
- Weinan Du
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Luchang Zhang
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Adina Brett-Morris
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Brittany Aguila
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Janos Kerner
- Department of Pharmacology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Charles L Hoppel
- Department of Pharmacology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.,Department of Medicine, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Michelle Puchowicz
- Department of Nutrition, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Dolors Serra
- Department of Biochemistry and Physiology, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, E-08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029, Madrid, Spain
| | - Laura Herrero
- Department of Biochemistry and Physiology, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, E-08028, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, E-28029, Madrid, Spain
| | - Brian I Rini
- Department of Hematology and Oncology, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Steven Campbell
- Department of Urology, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Scott M Welford
- Department of Radiation Oncology, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
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Minkler PE, Stoll MSK, Ingalls ST, Kerner J, Hoppel CL. Quantitative acylcarnitine determination by UHPLC-MS/MS--Going beyond tandem MS acylcarnitine "profiles". Mol Genet Metab 2015; 116:231-41. [PMID: 26458767 PMCID: PMC5009370 DOI: 10.1016/j.ymgme.2015.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 01/22/2023]
Abstract
Tandem MS "profiling" of acylcarnitines and amino acids was conceived as a first-tier screening method, and its application to expanded newborn screening has been enormously successful. However, unlike amino acid screening (which uses amino acid analysis as its second-tier validation of screening results), acylcarnitine "profiling" also assumed the role of second-tier validation, due to the lack of a generally accepted second-tier acylcarnitine determination method. In this report, we present results from the application of our validated UHPLC-MS/MS second-tier method for the quantification of total carnitine, free carnitine, butyrobetaine, and acylcarnitines to patient samples with known diagnoses: malonic acidemia, short-chain acyl-CoA dehydrogenase deficiency (SCADD) or isobutyryl-CoA dehydrogenase deficiency (IBD), 3-methyl-crotonyl carboxylase deficiency (3-MCC) or ß-ketothiolase deficiency (BKT), and methylmalonic acidemia (MMA). We demonstrate the assay's ability to separate constitutional isomers and diastereomeric acylcarnitines and generate values with a high level of accuracy and precision. These capabilities are unavailable when using tandem MS "profiles". We also show examples of research interest, where separation of acylcarnitine species and accurate and precise acylcarnitine quantification is necessary.
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MESH Headings
- Acetyl-CoA C-Acyltransferase/blood
- Acetyl-CoA C-Acyltransferase/cerebrospinal fluid
- Acetyl-CoA C-Acyltransferase/deficiency
- Acetyl-CoA C-Acyltransferase/urine
- Acyl-CoA Dehydrogenase/blood
- Acyl-CoA Dehydrogenase/cerebrospinal fluid
- Acyl-CoA Dehydrogenase/deficiency
- Acyl-CoA Dehydrogenase/urine
- Amino Acid Metabolism, Inborn Errors/blood
- Amino Acid Metabolism, Inborn Errors/cerebrospinal fluid
- Amino Acid Metabolism, Inborn Errors/diagnosis
- Amino Acid Metabolism, Inborn Errors/urine
- Betaine/analogs & derivatives
- Betaine/blood
- Betaine/cerebrospinal fluid
- Betaine/urine
- Carbon-Carbon Ligases/blood
- Carbon-Carbon Ligases/cerebrospinal fluid
- Carbon-Carbon Ligases/deficiency
- Carbon-Carbon Ligases/urine
- Carnitine/analogs & derivatives
- Carnitine/blood
- Carnitine/cerebrospinal fluid
- Carnitine/urine
- Chromatography, High Pressure Liquid/methods
- Chromatography, High Pressure Liquid/standards
- Female
- Humans
- Infant, Newborn
- Isomerism
- Lipid Metabolism, Inborn Errors/blood
- Lipid Metabolism, Inborn Errors/cerebrospinal fluid
- Lipid Metabolism, Inborn Errors/diagnosis
- Lipid Metabolism, Inborn Errors/urine
- Male
- Neonatal Screening
- Reproducibility of Results
- Sensitivity and Specificity
- Tandem Mass Spectrometry/standards
- Urea Cycle Disorders, Inborn/blood
- Urea Cycle Disorders, Inborn/cerebrospinal fluid
- Urea Cycle Disorders, Inborn/diagnosis
- Urea Cycle Disorders, Inborn/urine
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Affiliation(s)
- Paul E Minkler
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Maria S K Stoll
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Stephen T Ingalls
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Janos Kerner
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Charles L Hoppel
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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3
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Minkler PE, Stoll MSK, Ingalls ST, Kerner J, Hoppel CL. Validated method for the quantification of free and total carnitine, butyrobetaine, and acylcarnitines in biological samples. Anal Chem 2015; 87:8994-9001. [PMID: 26270397 DOI: 10.1021/acs.analchem.5b02198] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A validated quantitative method for the determination of free and total carnitine, butyrobetaine, and acylcarnitines is presented. The versatile method has four components: (1) isolation using strong cation-exchange solid-phase extraction, (2) derivatization with pentafluorophenacyl trifluoromethanesulfonate, (3) sequential ion-exchange/reversed-phase (ultra) high-performance liquid chromatography [(U)HPLC] using a strong cation-exchange trap in series with a fused-core HPLC column, and (4) detection with electrospray ionization multiple reaction monitoring (MRM) mass spectrometry (MS). Standardized carnitine along with 65 synthesized, standardized acylcarnitines (including short-chain, medium-chain, long-chain, dicarboxylic, hydroxylated, and unsaturated acyl moieties) were used to construct multiple-point calibration curves, resulting in accurate and precise quantification. Separation of the 65 acylcarnitines was accomplished in a single chromatogram in as little as 14 min. Validation studies were performed showing a high level of accuracy, precision, and reproducibility. The method provides capabilities unavailable by tandem MS procedures, making it an ideal approach for confirmation of newborn screening results and for clinical and basic research projects, including treatment protocol studies, acylcarnitine biomarker studies, and metabolite studies using plasma, urine, tissue, or other sample matrixes.
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Affiliation(s)
- Paul E Minkler
- Center for Mitochondrial Diseases, †Department of Pharmacology and ‡Department of Medicine, Case Western Reserve University School of Medicine , Cleveland, Ohio 44106, United States
| | - Maria S K Stoll
- Center for Mitochondrial Diseases, †Department of Pharmacology and ‡Department of Medicine, Case Western Reserve University School of Medicine , Cleveland, Ohio 44106, United States
| | - Stephen T Ingalls
- Center for Mitochondrial Diseases, †Department of Pharmacology and ‡Department of Medicine, Case Western Reserve University School of Medicine , Cleveland, Ohio 44106, United States
| | - Janos Kerner
- Center for Mitochondrial Diseases, †Department of Pharmacology and ‡Department of Medicine, Case Western Reserve University School of Medicine , Cleveland, Ohio 44106, United States
| | - Charles L Hoppel
- Center for Mitochondrial Diseases, †Department of Pharmacology and ‡Department of Medicine, Case Western Reserve University School of Medicine , Cleveland, Ohio 44106, United States
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Benmoussa N, Muller AL, Kerner J, Josset P, Conan P, Charlier P. [Paleopathology of deafness: skulls of the Dupuytren Museum]. Hist Sci Med 2015; 49:367-374. [PMID: 27029129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In the 18th and 19th centuries, the Dupuytren Museum was indispensable for the knowledge of pathological anatomy for physicians and surgeons. Nowadays, it is more a museum than a learning unit, but it provides an opportunity to understand through numerous scientific studies the origin of diseases, injuries mechanism and the functional consequences of which could suffer some patients. This study illustrates the interest of the study on pieces in pathological anatomy's museums, this time across selected skulls which belonged to hearing loss people. bizarre.
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5
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Kerner J, Liu J, Wang K, Fung S, Landry C, Lockwood G, Zitzelsberger L, Mai V. Canadian cancer screening disparities: a recent historical perspective. ACTA ACUST UNITED AC 2015; 22:156-63. [PMID: 25908914 DOI: 10.3747/co.22.2539] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Across Canada, introduction of the Pap test for cervical cancer screening, followed by mammography for breast cancer screening and, more recently, the fecal occult blood test for colorectal cancer screening, has contributed to a reduction in cancer mortality. However, another contribution of screening has been disparities in cancer mortality between certain populations. Here, we explore the disparities associated with breast and cervical cancer screening and preliminary data concerning disparities in colorectal cancer screening. Although some disparities in screening utilization have been successfully reduced over time (for example, mammography and Pap test screening in rural and remote populations), screening utilization data for other populations (for example, low-income groups) clearly indicate that disparities have existed and continue to exist across Canada. Organized screening programs in Canada have been able to successfully engage 80% of women for regular cervical cancer screening and 70% of women for regular mammography screening, but of the women who remain to be reached or engaged in regular screening, those with the least resources, those who are the most isolated, and those who are least culturally integrated into Canadian society as a whole are over-represented. Population differences are also observed for utilization of colorectal cancer screening services. The research literature on interventions to promote screening utilization provides some evidence about what can be done to increase participation in organized screening by vulnerable populations. Adaption and adoption of evidence-based screening promotion interventions can increase the utilization of available screening services by populations that have experienced the greatest burden of disease with the least access to screening services.
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Affiliation(s)
- J Kerner
- Canadian Partnership Against Cancer, Toronto, ON
| | - J Liu
- Canadian Partnership Against Cancer, Toronto, ON
| | - K Wang
- Canadian Partnership Against Cancer, Toronto, ON
| | - S Fung
- Canadian Partnership Against Cancer, Toronto, ON
| | - C Landry
- Canadian Partnership Against Cancer, Toronto, ON
| | - G Lockwood
- Canadian Partnership Against Cancer, Toronto, ON
| | | | - V Mai
- Canadian Partnership Against Cancer, Toronto, ON
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6
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Kerner J, Minkler P, Lesnefsky E, Hoppel C. Fatty acid chain elongation in palmitate‐perfused working rat heart: mitochondrial acetyl‐CoA is the source of two‐carbon units for chain elongation (758.2). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.758.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Janos Kerner
- Pharmacology Case Western Reserve UniversityClevelandOHUnited States
| | - Paul Minkler
- Pharmacology Case Western Reserve UniversityClevelandOHUnited States
| | | | - Charles Hoppel
- Pharmacology Case Western Reserve UniversityClevelandOHUnited States
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7
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Kerner J, Minkler PE, Lesnefsky EJ, Hoppel CL. Fatty acid chain elongation in palmitate-perfused working rat heart: mitochondrial acetyl-CoA is the source of two-carbon units for chain elongation. J Biol Chem 2014; 289:10223-34. [PMID: 24558043 DOI: 10.1074/jbc.m113.524314] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rat hearts were perfused with [1,2,3,4-(13)C4]palmitic acid (M+4), and the isotopic patterns of myocardial acylcarnitines and acyl-CoAs were analyzed using ultra-HPLC-MS/MS. The 91.2% (13)C enrichment in palmitoylcarnitine shows that little endogenous (M+0) palmitate contributed to its formation. The presence of M+2 myristoylcarnitine (95.7%) and M+2 acetylcarnitine (19.4%) is evidence for β-oxidation of perfused M+4 palmitic acid. Identical enrichment data were obtained in the respective acyl-CoAs. The relative (13)C enrichment in M+4 (84.7%, 69.9%) and M+6 (16.2%, 17.8%) stearoyl- and arachidylcarnitine, respectively, clearly shows that the perfused palmitate is chain-elongated. The observed enrichment of (13)C in acetylcarnitine (19%), M+6 stearoylcarnitine (16.2%), and M+6 arachidylcarnitine (17.8%) suggests that the majority of two-carbon units for chain elongation are derived from β-oxidation of [1,2,3,4-(13)C4]palmitic acid. These data are explained by conversion of the M+2 acetyl-CoA to M+2 malonyl-CoA, which serves as the acceptor for M+4 palmitoyl-CoA in chain elongation. Indeed, the (13)C enrichment in mitochondrial acetyl-CoA (18.9%) and malonyl-CoA (19.9%) are identical. No (13)C enrichment was found in acylcarnitine species with carbon chain lengths between 4 and 12, arguing against the simple reversal of fatty acid β-oxidation. Furthermore, isolated, intact rat heart mitochondria 1) synthesize malonyl-CoA with simultaneous inhibition of carnitine palmitoyltransferase 1b and 2) catalyze the palmitoyl-CoA-dependent incorporation of (14)C from [2-(14)C]malonyl-CoA into lipid-soluble products. In conclusion, rat heart has the capability to chain-elongate fatty acids using mitochondria-derived two-carbon chain extenders. The data suggest that the chain elongation process is localized on the outer surface of the mitochondrial outer membrane.
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8
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Prosdocimo DA, Anand P, Liao X, Zhu H, Shelkay S, Artero-Calderon P, Zhang L, Kirsh J, Moore D, Rosca MG, Vazquez E, Kerner J, Akat KM, Williams Z, Zhao J, Fujioka H, Tuschl T, Bai X, Schulze PC, Hoppel CL, Jain MK, Haldar SM. Kruppel-like factor 15 is a critical regulator of cardiac lipid metabolism. J Biol Chem 2014; 289:5914-24. [PMID: 24407292 DOI: 10.1074/jbc.m113.531384] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The mammalian heart, the body's largest energy consumer, has evolved robust mechanisms to tightly couple fuel supply with energy demand across a wide range of physiologic and pathophysiologic states, yet, when compared with other organs, relatively little is known about the molecular machinery that directly governs metabolic plasticity in the heart. Although previous studies have defined Kruppel-like factor 15 (KLF15) as a transcriptional repressor of pathologic cardiac hypertrophy, a direct role for the KLF family in cardiac metabolism has not been previously established. We show in human heart samples that KLF15 is induced after birth and reduced in heart failure, a myocardial expression pattern that parallels reliance on lipid oxidation. Isolated working heart studies and unbiased transcriptomic profiling in Klf15-deficient hearts demonstrate that KLF15 is an essential regulator of lipid flux and metabolic homeostasis in the adult myocardium. An important mechanism by which KLF15 regulates its direct transcriptional targets is via interaction with p300 and recruitment of this critical co-activator to promoters. This study establishes KLF15 as a key regulator of myocardial lipid utilization and is the first to implicate the KLF transcription factor family in cardiac metabolism.
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Affiliation(s)
- Domenick A Prosdocimo
- From the Case Cardiovascular Research Institute and Harrington Heart and Vascular Institute
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9
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Ruiz R, Jideonwo V, Ahn M, Surendran S, Tagliabracci VS, Hou Y, Gamble A, Kerner J, Irimia-Dominguez JM, Puchowicz MA, DePaoli-Roach A, Hoppel C, Roach P, Morral N. Sterol regulatory element-binding protein-1 (SREBP-1) is required to regulate glycogen synthesis and gluconeogenic gene expression in mouse liver. J Biol Chem 2014; 289:5510-7. [PMID: 24398675 DOI: 10.1074/jbc.m113.541110] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Sterol regulatory element-binding protein-1 (SREBP-1) is a key transcription factor that regulates genes in the de novo lipogenesis and glycolysis pathways. The levels of SREBP-1 are significantly elevated in obese patients and in animal models of obesity and type 2 diabetes, and a vast number of studies have implicated this transcription factor as a contributor to hepatic lipid accumulation and insulin resistance. However, its role in regulating carbohydrate metabolism is poorly understood. Here we have addressed whether SREBP-1 is needed for regulating glucose homeostasis. Using RNAi and a new generation of adenoviral vector, we have silenced hepatic SREBP-1 in normal and obese mice. In normal animals, SREBP-1 deficiency increased Pck1 and reduced glycogen deposition during fed conditions, providing evidence that SREBP-1 is necessary to regulate carbohydrate metabolism during the fed state. Knocking SREBP-1 down in db/db mice resulted in a significant reduction in triglyceride accumulation, as anticipated. However, mice remained hyperglycemic, which was associated with up-regulation of gluconeogenesis gene expression as well as decreased glycolysis and glycogen synthesis gene expression. Furthermore, glycogen synthase activity and glycogen accumulation were significantly reduced. In conclusion, silencing both isoforms of SREBP-1 leads to significant changes in carbohydrate metabolism and does not improve insulin resistance despite reducing steatosis in an animal model of obesity and type 2 diabetes.
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Affiliation(s)
- Rafaela Ruiz
- From the Departments of Medical and Molecular Genetics and
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10
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Gao XH, Qanungo S, Pai HV, Starke DW, Steller KM, Fujioka H, Lesnefsky EJ, Kerner J, Rosca MG, Hoppel CL, Mieyal JJ. Aging-dependent changes in rat heart mitochondrial glutaredoxins--Implications for redox regulation. Redox Biol 2013; 1:586-98. [PMID: 25126518 PMCID: PMC4127417 DOI: 10.1016/j.redox.2013.10.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 10/28/2013] [Accepted: 10/29/2013] [Indexed: 12/17/2022] Open
Abstract
Clinical and animal studies have documented that hearts of the elderly are more susceptible to ischemia/reperfusion damage compared to young adults. Recently we found that aging-dependent increase in susceptibility of cardiomyocytes to apoptosis was attributable to decrease in cytosolic glutaredoxin 1 (Grx1) and concomitant decrease in NF-κB-mediated expression of anti-apoptotic proteins. Besides primary localization in the cytosol, Grx1 also exists in the mitochondrial intermembrane space (IMS). In contrast, Grx2 is confined to the mitochondrial matrix. Here we report that Grx1 is decreased by 50–60% in the IMS, but Grx2 is increased by 1.4–2.6 fold in the matrix of heart mitochondria from elderly rats. Determination of in situ activities of the Grx isozymes from both subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria revealed that Grx1 was fully active in the IMS. However, Grx2 was mostly in an inactive form in the matrix, consistent with reversible sequestration of the active-site cysteines of two Grx2 molecules in complex with an iron–sulfur cluster. Our quantitative evaluations of the active/inactive ratio for Grx2 suggest that levels of dimeric Grx2 complex with iron–sulfur clusters are increased in SSM and IFM in the hearts of elderly rats. We found that the inactive Grx2 can be fully reactivated by sodium dithionite or exogenous superoxide production mediated by xanthine oxidase. However, treatment with rotenone, which generates intramitochondrial superoxide through inhibition of mitochondrial respiratory chain Complex I, did not lead to Grx2 activation. These findings suggest that insufficient ROS accumulates in the vicinity of dimeric Grx2 to activate it in situ. Glutaredoxins play key roles in cellular redox regulation, which is sensitive to aging-dependent dysregulation. Grx1 is diminished in the intermembrane space of mitochondria from aged heart; matrix Grx2 is increased but mostly in an inactive form. The inactive Grx2 is selectively activated by superoxide. Mitochondrial glutaredoxin changes may contribute to dysregulation of redox homeostasis during aging. Changes in in situ activities of heart mitochondrial Grx1 and Grx2 with aging provide mechanistic insights for future studies.
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Key Words
- Aging
- Cys-SSG, l-cysteine–glutathione mixed disulfide
- DT, sodium dithionite
- GSH, reduced glutathione
- GSSG, glutathione disulfide
- Glutaredoxin
- Glutathionylation
- Grx, glutaredoxin
- IFM, Heart interfibrillar mitochondria
- Iron–sulfur cluster
- Mitochondria
- Mn-TMPyP, Mn(III) tetrakis (1-methyl-4-pyridyl) porphyrin
- Reactive oxygen species (ROS)
- Redox regulation
- SSM, heart subsarcolemmal mitochondria
- t-Bid, caspase-8-cleaved human BID
- tetratosylate, hydroxide
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Affiliation(s)
- Xing-Huang Gao
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Suparna Qanungo
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Harish V Pai
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - David W Starke
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Kelly M Steller
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA ; Louis Stokes Cleveland Veterans Affairs Medical Research Center, Cleveland, OH 44106, USA
| | - Hisashi Fujioka
- Center for Mitochondrial Disease, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Edward J Lesnefsky
- Department of Medicine, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Janos Kerner
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA ; Center for Mitochondrial Disease, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Mariana G Rosca
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA ; Center for Mitochondrial Disease, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Charles L Hoppel
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA ; Center for Mitochondrial Disease, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA ; Department of Medicine, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - John J Mieyal
- Department of Pharmacology, Division of Cardiology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA ; Louis Stokes Cleveland Veterans Affairs Medical Research Center, Cleveland, OH 44106, USA
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11
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Rosca MG, Vazquez EJ, Chen Q, Kerner J, Kern TS, Hoppel CL. Oxidation of fatty acids is the source of increased mitochondrial reactive oxygen species production in kidney cortical tubules in early diabetes. Diabetes 2012; 61:2074-83. [PMID: 22586586 PMCID: PMC3402323 DOI: 10.2337/db11-1437] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial reactive oxygen species (ROS) cause kidney damage in diabetes. We investigated the source and site of ROS production by kidney cortical tubule mitochondria in streptozotocin-induced type 1 diabetes in rats. In diabetic mitochondria, the increased amounts and activities of selective fatty acid oxidation enzymes is associated with increased oxidative phosphorylation and net ROS production with fatty acid substrates (by 40% and 30%, respectively), whereas pyruvate oxidation is decreased and pyruvate-supported ROS production is unchanged. Oxidation of substrates that donate electrons at specific sites in the electron transport chain (ETC) is unchanged. The increased maximal production of ROS with fatty acid oxidation is not affected by limiting the electron flow from complex I into complex III. The maximal capacity of the ubiquinol oxidation site in complex III in generating ROS does not differ between the control and diabetic mitochondria. In conclusion, the mitochondrial ETC is neither the target nor the site of ROS production in kidney tubule mitochondria in short-term diabetes. Mitochondrial fatty acid oxidation is the source of the increased net ROS production, and the site of electron leakage is located proximal to coenzyme Q at the electron transfer flavoprotein that shuttles electrons from acyl-CoA dehydrogenases to coenzyme Q.
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Affiliation(s)
- Mariana G Rosca
- Center of Mitochondrial Diseases, Case Western Reserve University, Cleveland, Ohio, USA.
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12
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Haldar SM, Jeyaraj D, Anand P, Zhu H, Lu Y, Prosdocimo DA, Eapen B, Kawanami D, Okutsu M, Brotto L, Fujioka H, Kerner J, Rosca MG, McGuinness OP, Snow RJ, Russell AP, Gerber AN, Bai X, Yan Z, Nosek TM, Brotto M, Hoppel CL, Jain MK. Kruppel-like factor 15 regulates skeletal muscle lipid flux and exercise adaptation. Proc Natl Acad Sci U S A 2012; 109:6739-44. [PMID: 22493257 PMCID: PMC3340075 DOI: 10.1073/pnas.1121060109] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of skeletal muscle to enhance lipid utilization during exercise is a form of metabolic plasticity essential for survival. Conversely, metabolic inflexibility in muscle can cause organ dysfunction and disease. Although the transcription factor Kruppel-like factor 15 (KLF15) is an important regulator of glucose and amino acid metabolism, its endogenous role in lipid homeostasis and muscle physiology is unknown. Here we demonstrate that KLF15 is essential for skeletal muscle lipid utilization and physiologic performance. KLF15 directly regulates a broad transcriptional program spanning all major segments of the lipid-flux pathway in muscle. Consequently, Klf15-deficient mice have abnormal lipid and energy flux, excessive reliance on carbohydrate fuels, exaggerated muscle fatigue, and impaired endurance exercise capacity. Elucidation of this heretofore unrecognized role for KLF15 now implicates this factor as a central component of the transcriptional circuitry that coordinates physiologic flux of all three basic cellular nutrients: glucose, amino acids, and lipids.
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Affiliation(s)
- Saptarsi M Haldar
- Harrington Heart and Vascular Institute and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, Cleveland, OH 44106, USA.
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13
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Kerner J, Virmani A, Koverech A, Hoppel C. Effect of propionylcarnitine on mitochondrial energy metabolism in elderly rat heart. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.785.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Janos Kerner
- PharmacologyCase Western Reserve UniversityClevelandOH
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14
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Lee K, Kerner J, Hoppel C. Isolation and mass spectrometric analysis of native protein complexes in rat liver mitochondrial contact sites. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.988.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kwangwon Lee
- Center for Mitochondrial DiseaseCase Western Reserve UniversityClevelandOH
- PharmacologyCase Western Reserve UniversityClevelandOH
| | - Janos Kerner
- Center for Mitochondrial DiseaseCase Western Reserve UniversityClevelandOH
- PharmacologyCase Western Reserve UniversityClevelandOH
| | - Charles Hoppel
- Center for Mitochondrial DiseaseCase Western Reserve UniversityClevelandOH
- PharmacologyCase Western Reserve UniversityClevelandOH
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15
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Lee K, Kerner J, Hoppel CL. Mitochondrial carnitine palmitoyltransferase 1a (CPT1a) is part of an outer membrane fatty acid transfer complex. J Biol Chem 2011; 286:25655-62. [PMID: 21622568 DOI: 10.1074/jbc.m111.228692] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
CPT1a (carnitine palmitoyltransferase 1a) in the liver mitochondrial outer membrane (MOM) catalyzes the primary regulated step in overall mitochondrial fatty acid oxidation. It has been suggested that the fundamental unit of CPT1a exists as a trimer, which, under native conditions, could form a dimer of the trimers, creating a hexamer channel for acylcarnitine translocation. To examine the state of CPT1a in the MOM, we employed a combined approach of sizing by mass and isolation using an immunological method. Blue native electrophoresis followed by detection with immunoblotting and mass spectrometry identified large molecular mass complexes that contained not only CPT1a but also long chain acyl-CoA synthetase (ACSL) and the voltage-dependent anion channel (VDAC). Immunoprecipitation with antisera against the proteins revealed a strong interaction between the three proteins. Immobilized CPT1a-specific antibodies immunocaptured not only CPT1a but also ACSL and VDAC, further strengthening findings with blue native electrophoresis and immunoprecipitation. This study shows strong protein-protein interaction between CPT1a, ACSL, and VDAC. We propose that this complex transfers activated fatty acids through the MOM.
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Affiliation(s)
- Kwangwon Lee
- Center for Mitochondrial Diseases, Cleveland, Ohio 44106-4981, USA
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Abstract
Parenteral nutrition (PN), containing fat emulsions derived from soybean, has been implicated in the progression of PN-associated liver disease and cholestasis, particularly in infants with short bowel syndrome. Clinical use of Omegaven, a parenteral fish-oil emulsion, has been shown in recent studies to be a promising therapy to reverse liver disease and cholestasis. This review summarizes the rationale, relevant clinical investigations and future direction of Omegaven therapy for PN-dependent infants.
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Affiliation(s)
- K T Park
- Department of Pediatric Gastroenterology, Stanford University Medical Center, Lucile Packard Children's Hospital, 750 Welch Road, Palo Alto, CA 94304, USA
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Lee K, Kerner J, Hoppel CL. A liver mitochondrial outer membrane (MOM) fatty acid transfer complex. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.850.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Charles L. Hoppel
- Pharmacology and Medicine
- Center for Mitochondrial DiseaseCase Western Reserve UniversityClevelandOH
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Kerner J, Yohannes E, Virmani A, Koverech A, Chance M, Hoppel C. Acetylcarnitine treatment increases mitochondrial protein‐lysine acetylation and protein expression. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.660.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Elizabeth Yohannes
- Center for Proteomics and BioinformaticsCase Western Reserve UniversityClevelandOH
| | | | | | - Marc Chance
- Center for Proteomics and BioinformaticsCase Western Reserve UniversityClevelandOH
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20
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Papapetropoulos S, Tibbetts A, Seitzman R, Kerner J, Barnard J, Ward A, Michels S, O'Neil G. P1.156 Non-motor comorbidities in patients with Parkinson's disease: a US claims database analysis. Parkinsonism Relat Disord 2009. [DOI: 10.1016/s1353-8020(09)70278-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Kerner J, Minkler P, Stoll M, Hoppel C. Fatty acid beta oxidation is the source of malonyl‐CoA for fatty acid chain elongation in rat heart. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.793.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Charles Hoppel
- Pharmacology and MedicineCase Western Reserve UniversityClevelandOH
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Abstract
For the proteomic study of mitochondrial membranes, documented high quality mitochondrial preparations are a necessity to ensure proper localization. Despite the state-of-the-art technologies currently in use, there is no single technique that can be used for all studies of mitochondrial membrane proteins. Herein, we use examples to highlight solubilization techniques, different chromatographic methods, and developments in gel electrophoresis for proteomic analysis of mitochondrial membrane proteins. Blue-native gel electrophoresis has been successful not only for dissection of the inner membrane oxidative phosphorylation system, but also for the components of the outer membrane such as those involved in protein import. Identification of PTMs such as phosphorylation, acetylation, and nitration of mitochondrial membrane proteins has been greatly improved by the use of affinity techniques. However, understanding of the biological effect of these modifications is an area for further exploration. The rapid development of proteomic methods for both identification and quantitation, especially for modifications, will greatly impact the understanding of the mitochondrial membrane proteome.
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Affiliation(s)
- Anne M Distler
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
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23
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Abstract
In recent years, a wide variety of proteomic approaches using gel electrophoresis and mass spectrometry has been developed to detect post-translational modifications. Mitochondria are often a focus of these studies due to their important role in cellular function. Many of their crucial transport and oxidative-phosphorylation functions are performed by proteins residing in the inner and outer membranes of the mitochondria. Although proteomic technologies have greatly enhanced our understanding of regulation in cellular processes, analysis of membrane proteins has lagged behind that of soluble proteins. Herein, we present techniques to facilitate the detection of post-translational modifications of mitochondrial membrane proteins including the isolation of resident membranes as well as electrophoretic and immunological-based methods for identification of post-translational modifications.
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Affiliation(s)
- Anne M Distler
- Department of Pharmacology, and Center for Mitochondrial Disease, Case Western Reserve University, Cleveland, Ohio, USA
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24
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Rosca MG, Vazquez EJ, Kerner J, Parland W, Chandler MP, Stanley W, Sabbah HN, Hoppel CL. Cardiac mitochondria in heart failure: decrease in respirasomes and oxidative phosphorylation. Cardiovasc Res 2008; 80:30-9. [PMID: 18710878 PMCID: PMC2533423 DOI: 10.1093/cvr/cvn184] [Citation(s) in RCA: 285] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Aims Mitochondrial dysfunction is a major factor in heart failure (HF). A pronounced variability of mitochondrial electron transport chain (ETC) defects is reported to occur in severe acquired cardiomyopathies without a consistent trend for depressed activity or expression. The aim of this study was to define the defect in the integrative function of cardiac mitochondria in coronary microembolization-induced HF. Methods and results Studies were performed in the canine coronary microembolization-induced HF model of moderate severity. Oxidative phosphorylation was assessed as the integrative function of mitochondria, using a comprehensive variety of substrates in order to investigate mitochondrial membrane transport, dehydrogenase activity and electron-transport coupled to ATP synthesis. The supramolecular organization of the mitochondrial ETC also was investigated by native gel electrophoresis. We found a dramatic decrease in ADP-stimulated respiration that was not relieved by an uncoupler. Moreover, the ADP/O ratio was normal, indicating no defect in the phosphorylation apparatus. The data point to a defect in oxidative phosphorylation within the ETC. However, the individual activities of ETC complexes were normal. The amount of the supercomplex consisting of complex I/complex III dimer/complex IV, the major form of respirasome considered essential for oxidative phosphorylation, was decreased. Conclusions We propose that the mitochondrial defect lies in the supermolecular assembly rather than in the individual components of the ETC.
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Affiliation(s)
- Mariana G Rosca
- Department of Medicine, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland 44106-4981, OH, USA
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25
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Minkler PE, Stoll MSK, Ingalls ST, Yang S, Kerner J, Hoppel CL. Quantification of carnitine and acylcarnitines in biological matrices by HPLC electrospray ionization-mass spectrometry. Clin Chem 2008; 54:1451-62. [PMID: 18678604 DOI: 10.1373/clinchem.2007.099226] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Analysis of carnitine and acylcarnitines by tandem mass spectrometry (MS/MS) has limitations. First, preparation of butyl esters partially hydrolyzes acylcarnitines. Second, isobaric nonacylcarnitine compounds yield false-positive results in acylcarnitine tests. Third, acylcarnitine constitutional isomers cannot be distinguished. METHODS Carnitine and acylcarnitines were isolated by ion-exchange solid-phase extraction, derivatized with pentafluorophenacyl trifluoromethanesulfonate, separated by HPLC, and detected with an ion trap mass spectrometer. Carnitine was quantified with d(3)-carnitine as the internal standard. Acylcarnitines were quantified with 42 synthesized calibrators. The internal standards used were d(6)-acetyl-, d(3)-propionyl-, undecanoyl-, undecanedioyl-, and heptadecanoylcarnitine. RESULTS Example recoveries [mean (SD)] were 69.4% (3.9%) for total carnitine, 83.1% (5.9%) for free carnitine, 102.2% (9.8%) for acetylcarnitine, and 107.2% (8.9%) for palmitoylcarnitine. Example imprecision results [mean (SD)] within runs (n = 6) and between runs (n = 18) were, respectively: total carnitine, 58.0 (0.9) and 57.4 (1.7) micromol/L; free carnitine, 44.6 (1.5) and 44.3 (1.2) micromol/L; acetylcarnitine, 7.74 (0.51) and 7.85 (0.69) micromol/L; and palmitoylcarnitine, 0.12 (0.01) and 0.11 (0.02) micromol/L. Standard-addition slopes and linear regression coefficients were 1.00 and 0.9998, respectively, for total carnitine added to plasma, 0.99 and 0.9997 for free carnitine added to plasma, 1.04 and 0.9972 for octanoylcarnitine added to skeletal muscle, and 1.05 and 0.9913 for palmitoylcarnitine added to skeletal muscle. Reference intervals for plasma, urine, and skeletal muscle are provided. CONCLUSIONS This method for analysis of carnitine and acylcarnitines overcomes the observed limitations of MS/MS methods.
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Affiliation(s)
- Paul E Minkler
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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26
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Kerner J, Parland WK, Minkler PE, Hoppel CL. Rat liver mitochondrial carnitine palmitoyltransferase-I, hepatic carnitine, and malonyl-CoA: effect of starvation. Arch Physiol Biochem 2008; 114:161-70. [PMID: 18629681 DOI: 10.1080/13813450802181062] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Hepatic mitochondrial fatty acid oxidation and ketogenesis increase during starvation. Carnitine palmitoyltransferase I (CPT-I) catalyses the rate-controlling step in the overall pathway and retains its control over beta-oxidation under fed, starved and diabetic conditions. To determine the factors contributing to the reported several-fold increase in fatty acid oxidation in perfused livers, we measured the V(max) and K(m) values for palmitoyl-CoA and carnitine, the K(i) (and IC(50)) values for malonyl-CoA in isolated liver mitochondria as well as the hepatic malonyl-CoA and carnitine contents in control and 48 h starved rats. Since CPT-I is localized in the mitochondrial outer membrane and in contact sites, the kinetic properties of CPT-I also was determined in these submitochondrial structures. After 48 h starvation, there is: (a) a significant increase in K(i) and decrease in hepatic malonyl-CoA content; (b) a decreased K(m) for palmitoyl-CoA; and (c) increased catalytic activity (V(max)) and CPT-I protein abundance that is significantly greater in contact sites compared with outer membranes. Based on these changes the estimated increase in mitochondrial fatty acid oxidation is significantly less than that observed in perfused liver. This suggests that CPT-I is regulated in vivo by additional mechanism(s) lost during mitochondrial isolation or/and that mitochondrial oxidation of peroxisomal beta-oxidation products contribute to the increased ketogenesis by bypassing CPT-I. Furthermore, the greater increase in CPT-I protein in contact sites as compared to outer membranes emphasizes the significance of contact sites in hepatic fatty acid oxidation.
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Affiliation(s)
- Janos Kerner
- Department of Nutrition, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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27
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Ji S, You Y, Kerner J, Hoppel CL, Schoeb TR, Chick WS, Hamm DA, Sharer JD, Wood PA. Homozygous carnitine palmitoyltransferase 1b (muscle isoform) deficiency is lethal in the mouse. Mol Genet Metab 2008; 93:314-22. [PMID: 18023382 PMCID: PMC2270477 DOI: 10.1016/j.ymgme.2007.10.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Accepted: 10/06/2007] [Indexed: 11/29/2022]
Abstract
Carnitine palmitoyltransferase-1 (CPT-1) catalyzes the rate-limiting step of mitochondrial beta-oxidation of long chain fatty acids (LCFA), the most abundant fatty acids in mammalian membranes and in energy metabolism. Human deficiency of the muscle isoform CPT-1b is poorly understood. In the current study, embryos with a homozygous knockout of Cpt-1b were lost before embryonic day 9.5-11.5. Also, while there were normal percentages of CPT-1b+/- pups born from both male and female CPT-1b+/- mice crossed with wild-type mates, the number of CPT-1b+/- pups from CPT-1b+/- breeding pairs was under-represented (63% of the expected number). Northern blot analysis demonstrated approximately 50% Cpt-1b mRNA expression in brown adipose tissue (BAT), heart and skeletal muscles in the CPT-1b+/- male mice. Consistent with tissue-specific expression of Cpt-1b mRNA in muscle but not liver, CPT-1+/- mice had approximately 60% CPT-1 activity in skeletal muscle and no change in total liver CPT-1 activity. CPT-1b+/- mice had normal fasting blood glucose concentration. Consistent with expression of CPT-1b in BAT and muscle, approximately 7% CPT-1b+/- mice (n=30) developed fatal hypothermia following a 3h cold challenge, while none of the CPT-1b+/+ mice (n=30) did. With a prolonged cold challenge (6h), significantly more CPT-1b+/- mice developed fatal hypothermia (52% CPT-1b+/- mice vs. 21% CPT-1b+/+ mice), with increased frequency in females of both genotypes (67% female vs. 38% male CPT-1b+/- mice, and 33% female vs. 8% male CPT-1b+/+ mice). Therefore, lethality of homozygous CPT-1b deficiency in the mice is consistent with paucity of human cases.
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Affiliation(s)
- Shaonin Ji
- Department of Genetics, University of Alabama at Birmingham, USA
| | - Yun You
- Mammalian Genetics & Genomics, Life Sciences Division, Oak Ridge National Laboratory, USA
| | - Janos Kerner
- Department of Nutrition, Case Western Reserve University, School of Medicine, Cleveland, OH, USA
| | - Charles L. Hoppel
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University, School of Medicine, Cleveland, OH, USA
| | | | - Wallace S.H. Chick
- Mammalian Genetics & Genomics, Life Sciences Division, Oak Ridge National Laboratory, USA
| | - Doug A. Hamm
- Department of Genetics, University of Alabama at Birmingham, USA
| | - J. Daniel Sharer
- Department of Genetics, University of Alabama at Birmingham, USA
| | - Philip A. Wood
- Department of Genetics, University of Alabama at Birmingham, USA
- Corresponding author. FAX: 205−975−4418 Telephone: 205−934−1303 e-mail: web: www.uab.edu/genetics
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King KL, Stanley WC, Rosca M, Kerner J, Hoppel CL, Febbraio M. Fatty acid oxidation in cardiac and skeletal muscle mitochondria is unaffected by deletion of CD36. Arch Biochem Biophys 2007; 467:234-8. [PMID: 17904092 PMCID: PMC2702466 DOI: 10.1016/j.abb.2007.08.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 08/17/2007] [Accepted: 08/18/2007] [Indexed: 11/20/2022]
Abstract
Recent studies found that the plasma membrane fatty acid transport protein CD36 also resides in mitochondrial membranes in cardiac and skeletal muscle. Pharmacological studies suggest that CD36 may play an essential role in mitochondrial fatty acid oxidation. We isolated cardiac and skeletal muscle mitochondria from wild type and CD36 knock-out mice. There were no differences between wild type and CD36 knock-out mice in mitochondrial respiration with palmitoyl-CoA, palmitoyl-carnitine or glutamate as substrate. We investigated a potential alternative role for CD36 in mitochondria, i.e. the export of fatty acids generated in the matrix. Palmitate export was not different between wild type and CD36 knock-out mice. Taken together, CD36 does not appear to play an essential role in mitochondrial uptake of fatty acids or export of fatty acid anions.
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Affiliation(s)
- Kristen L. King
- Department of Physiology and Biophysics, Case Western Reserve University; Cleveland, USA
| | - William C. Stanley
- Department of Physiology and Biophysics, Case Western Reserve University; Cleveland, USA
- Department of Nutrition, Case Western Reserve University; Cleveland, USA
- Department of Medicine, Division of Cardiology, University of Maryland, Baltimore, USA
| | - Mariana Rosca
- Department of Pharmacology. School of Medicine, Case Western Reserve University; Cleveland, USA
| | - Janos Kerner
- Department of Nutrition, Case Western Reserve University; Cleveland, USA
| | - Charles L. Hoppel
- Department of Pharmacology. School of Medicine, Case Western Reserve University; Cleveland, USA
| | - Maria Febbraio
- Department of Cell Biology, Cleveland Clinic, Lerner Institute; Cleveland, USA
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Kerner J, Minkler PE, Lesnefsky EJ, Hoppel CL. Fatty acid chain-elongation in perfused rat heart: synthesis of stearoylcarnitine from perfused palmitate. FEBS Lett 2007; 581:4491-4. [PMID: 17761175 PMCID: PMC2743553 DOI: 10.1016/j.febslet.2007.08.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2007] [Accepted: 08/14/2007] [Indexed: 10/22/2022]
Abstract
Rat hearts perfused for up to 60 min in the working mode with palmitate, but not with glucose, resulted in substantial formation of palmitoylcarnitine and stearoylcarnitine. To test whether lipolysis of endogenous lipids was responsible for the increased stearoylcarnitine content or whether some of the perfused palmitate underwent chain elongation, hearts were perfused with hexadecanoic-16,16,16-d(3) acid (M+3). The pentafluorophenacyl ester of deuterium labeled stearoylcarnitine had an M+3 (639.4 m/z) compared to the unlabeled M+0 (636.3 m/z) consistent with a direct chain elongation of the perfused palmitate. Furthermore, the near equal isotope enrichment of palmitoyl- (90.2+/-5.8%) and stearoylcarnitine (78.0+/-7.1%) suggest that both palmitoyl- and stearoyl-CoA have ready access to mitochondrial carnitine palmitoyltransferase and that most of the stearoylcarnitine is derived from the perfused palmitate.
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Affiliation(s)
- Janos Kerner
- Case Western Reserve University, School of Medicine, Department of Nutrition, Cleveland, OH 44106, United States.
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King KL, Young ME, Kerner J, Huang H, O'Shea KM, Alexson SEH, Hoppel CL, Stanley WC. Diabetes or peroxisome proliferator-activated receptor alpha agonist increases mitochondrial thioesterase I activity in heart. J Lipid Res 2007; 48:1511-7. [PMID: 17438340 DOI: 10.1194/jlr.m600364-jlr200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peroxisome proliferator-activated receptor alpha (PPAR alpha) is a transcriptional regulator of the expression of mitochondrial thioesterase I (MTE-I) and uncoupling protein 3 (UCP3), which are induced in the heart at the mRNA level in response to diabetes. Little is known about the regulation of protein expression of MTE-I and UCP3 or about MTE-I activity; thus, we investigated the effects of diabetes and treatment with a PPAR alpha agonist on these parameters. Rats were either made diabetic with streptozotocin (55 mg/kg ip) and maintained for 10-14 days or treated with the PPAR alpha agonist fenofibrate (300 mg/kg/day) for 4 weeks. MTE-I and UCP3 protein expression, MTE-1 activity, palmitate export, and oxidative phosphorylation were measured in isolated cardiac mitochondria. Diabetes and fenofibrate increased cardiac MTE-I mRNA, protein, and activity ( approximately 4-fold compared with controls). This increase in activity was matched by a 6-fold increase in palmitate export in fenofibrate-treated animals, despite there being no effect in either group on UCP3 protein expression. Both diabetes and fenofibrate caused significant decreases in state III respiration of isolated mitochondria with pyruvate + malate as the substrate, but only diabetes reduced state III rates with palmitoylcarnitine. Both diabetes and specific PPAR alpha activation increased MTE-I protein, activity, and palmitate export in the heart, with little effect on UCP3 protein expression.
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Affiliation(s)
- Kristen L King
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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Kerner J, Minkler P, Parland W, Lesnefsky E, Hoppel C. Effect Of Age, Anesthesia, And Ischemia/Reperfusion With Palmitate On Myocardial Acylcarnitines. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a716-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Paul Minkler
- PharmacologyCase Western Reserve University2109 Adalbert Road, Room W517, Wood Bldg.ClevelandOH44106
| | - William Parland
- MedicineCase Western Reserve University2109 Adalbert Road, Room W161, Wood Bldg.ClevelandOH44106
| | - Edward Lesnefsky
- Medical Research ServiceLouis Stokes VA Medical Center10701 East BoulevardClevelandOH44106
| | - Charles Hoppel
- Pharmacology and MedicineCase Western Reserve University2109 Adalbert Road, Room W165, Wood Bldg.ClevelandOH44106
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Distler AM, Kerner J, Hoppel CL. Post-translational modifications of rat liver mitochondrial outer membrane proteins identified by mass spectrometry. Biochim Biophys Acta 2007; 1774:628-36. [PMID: 17478130 PMCID: PMC1950290 DOI: 10.1016/j.bbapap.2007.03.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 03/13/2007] [Accepted: 03/14/2007] [Indexed: 12/17/2022]
Abstract
The identification of post-translational modifications is difficult especially for hydrophobic membrane proteins. Here we present the identification of several types of protein modifications on membrane proteins isolated from mitochondrial outer membranes. We show, in vivo, that the mature rat liver mitochondrial carnitine palmitoyltransferase-I enzyme is N-terminally acetylated, phosphorylated on two threonine residues, and nitrated on two tyrosine residues. We show that long chain acyl-CoA synthetase 1 is acetylated at both the N-terminal end and at a lysine residue and tyrosine residues are found to be phosphorylated and nitrated. For the three voltage-dependent anion channel isoforms present in the mitochondria, the N-terminal regions of the protein were determined and sites of phosphorylation were identified. These novel findings raise questions about regulatory aspects of carnitine palmitoyltransferase-I, long chain acyl-CoA synthetase and voltage dependent anion channel and further studies should advance our understanding about regulation of mitochondrial fatty acid oxidation in general and these three proteins in specific.
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Affiliation(s)
- Anne M. Distler
- Department of Medicine, Case Western Reserve University and Medical Research Service, Cleveland OH, 44106
- Department of Nutrition, Case Western Reserve University and Medical Research Service, Cleveland OH, 44106
| | - Janos Kerner
- Department of Medicine, Case Western Reserve University and Medical Research Service, Cleveland OH, 44106
- Department of Nutrition, Case Western Reserve University and Medical Research Service, Cleveland OH, 44106
| | - Charles L. Hoppel
- Department of Medicine, Case Western Reserve University and Medical Research Service, Cleveland OH, 44106
- Department of Pharmacology, Case Western Reserve University and Medical Research Service, Cleveland OH, 44106
- Louis Stokes Department of Veterans Affairs Medical Center, Cleveland OH, 44106
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Rosca MG, Vazquez EJ, Kerner J, Stanley W, Recchia F, Hoppel CL. Pacing‐induced heart failure causes specific defects in the phosphorylation apparatus in skeletal muscle mitochondria. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a945-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - William Stanley
- Physiology and BiophysicsCase Western Reserve University2085 Adelbert Str.ClevelandOH44106
| | - Fabio Recchia
- PhysiologyNew York Medical College, ValhallaValhallaNY10595
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Bian F, Kasumov T, Jobbins KA, Minkler PE, Anderson VE, Kerner J, Hoppel CL, Brunengraber H. Competition between acetate and oleate for the formation of malonyl-CoA and mitochondrial acetyl-CoA in the perfused rat heart. J Mol Cell Cardiol 2006; 41:868-75. [PMID: 17020764 PMCID: PMC1941666 DOI: 10.1016/j.yjmcc.2006.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 07/28/2006] [Accepted: 08/17/2006] [Indexed: 11/29/2022]
Abstract
We previously showed that, in the perfused rat heart, the capacity of n-fatty acids to generate mitochondrial acetyl-CoA decreases as their chain length increases. In the present study, we investigated whether the oxidation of a long-chain fatty acid, oleate, is inhibited by short-chain fatty acids, acetate or propionate (which do and do not generate mitochondrial acetyl-CoA, respectively). We perfused rat hearts with buffer containing 4 mM glucose, 0.2 mM pyruvate, 1 mM lactate, and various concentrations of either (i) [U-(13)C]acetate, (ii) [U-(13)C]acetate plus [1-(13)C]oleate, or (iii) unlabeled propionate plus [1-(13)C]oleate. Using mass isotopomer analysis, we determined the contributions of the labeled substrates to the acetyl moiety of citrate (a probe of mitochondrial acetyl-CoA) and to malonyl-CoA. We found that acetate, even at low concentration, markedly inhibits the oxidation of [1-(13)C]oleate in the heart, without change in malonyl-CoA concentration. We also found that propionate, at a concentration higher than 1 mM, decreases (i) the contribution of [1-(13)C]oleate to mitochondrial acetyl-CoA and (ii) malonyl-CoA concentration. The inhibition by acetate or propionate of acetyl-CoA production from oleate probably results from a competition for mitochondrial CoA between the CoA-utilizing enzymes.
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Affiliation(s)
- Fang Bian
- Department of Nutrition, Case Western Reserve University, Cleveland OH 44106
| | - Takhar Kasumov
- Department of Nutrition, Case Western Reserve University, Cleveland OH 44106
| | - Kathryn A. Jobbins
- Department of Nutrition, Case Western Reserve University, Cleveland OH 44106
| | - Paul E. Minkler
- Department of Pharmacology, Case Western Reserve University, Cleveland OH 44106
| | - Vernon E. Anderson
- Department of Biochemistry, Case Western Reserve University, Cleveland OH 44106
| | - Janos Kerner
- Department of Nutrition, Case Western Reserve University, Cleveland OH 44106
| | - Charles L. Hoppel
- Department of Pharmacology, Case Western Reserve University, Cleveland OH 44106
| | - Henri Brunengraber
- Department of Nutrition, Case Western Reserve University, Cleveland OH 44106
- * To whom correspondence should be addressed: Department of Nutrition, Case Western Reserve University, 2109 Adelbert Road, room BRB923, Cleveland OH 44106-4906. Tel: (216)368-6548; E-mail:
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35
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Distler AM, Kerner J, Peterman SM, Hoppel CL. A targeted proteomic approach for the analysis of rat liver mitochondrial outer membrane proteins with extensive sequence coverage. Anal Biochem 2006; 356:18-29. [PMID: 16876102 DOI: 10.1016/j.ab.2006.03.053] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 03/23/2006] [Accepted: 03/31/2006] [Indexed: 11/19/2022]
Abstract
Membrane proteins play an important role in cellular function. However, their analysis by mass spectrometry often is hindered by their hydrophobicity and/or low abundance. In this article, we present a method for the mass spectrometric analysis of membrane proteins based on the isolation of the resident membranes, isolation of the proteins by gel electrophoresis, and electroelution followed by enzymatic digestion by both trypsin and proteinase K. With this method, we have achieved 82-99% sequence coverage for the membrane proteins carnitine palmitoyltransferase-I (CPT-I), long-chain acyl-CoA synthetase (LCAS), and voltage-dependent anion channel (VDAC), isolated from rat liver mitochondrial outer membranes, including the transmembrane domains of these integral membrane proteins. This high sequence coverage allowed the identification of the isoforms of the proteins under study. This methodology provides a targeted approach for examining membrane proteins in detail.
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Affiliation(s)
- Anne M Distler
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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36
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Minkler PE, Kerner J, Kasumov T, Parland W, Hoppel CL. Quantification of malonyl-coenzyme A in tissue specimens by high-performance liquid chromatography/mass spectrometry. Anal Biochem 2006; 352:24-32. [PMID: 16545769 DOI: 10.1016/j.ab.2006.02.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 12/15/2005] [Accepted: 02/08/2006] [Indexed: 11/18/2022]
Abstract
We present a validated high-performance liquid chromatography/mass spectrometry (HPLC/MS) method for the quantification of malonyl-coenzyme A (CoA) in tissues. The assay consists of extraction of malonyl-CoA from tissue using 10% trichloroacetic acid, isolation using a reversed-phase solid-phase extraction column, HPLC separation, and detection using electrospray MS. Quantification was performed using an internal standard ([(13)C(3)]malonyl-CoA) and multiple-point standard curves from 50 to 1000pmol. The procedure was validated by performing recovery, accuracy, and precision studies. Recoveries of malonyl-CoA were determined to be 28.8+/-0.9, 48.5+/-1.8, and 44.7+/-4.4% (averages+/-SD, n=5) for liver, heart, and skeletal muscle, respectively. Accuracy was demonstrated by the addition of known amounts of malonyl-CoA to tissue samples. The malonyl-CoA detected was compared with the malonyl-CoA added, and the resulting relationships were linear with slopes and regression coefficients equal to 1. Precision was demonstrated by repetitive analysis of identical samples. These showed a within-run variation between 5 and 11%, and the interbatch repeatability was essentially the same. This procedure was then applied to rat liver, heart, and skeletal muscle, where the malonyl-CoA contents were found to be 1.9+/-0.6, 1.3+/-0.4, and 0.7+/-0.2nmol/g wet weight, respectively, for these tissues. This analytical approach can be extended to the quantification of other acyl-CoA species with no significant modification.
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Affiliation(s)
- Paul E Minkler
- Louis Stokes Department of Veterans Affairs Medical Center, Medical Research Service, Cleveland, OH 44106, USA
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37
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Distler AM, Kerner J, Hoppel CL. Post‐translational Modifications of the Mitochondrial Outer Membrane Proteins: Carnitine Palmitoyltransferase‐I, Long‐chain acyl‐CoA synthetase, and Voltage Dependent Anion Channel. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a139-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Charles L. Hoppel
- Pharmacology and MedicineCase Western Reserve UniversityVA Medical Center151W, 10701 East Blvd.ClevelandOH44106
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38
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Kerner J, Minkler P, Hoppel C. Is there a single malonyl‐CoA pool in the heart for regulation of carnitine palmitoyltransferase‐I and fatty acid chain elongation. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a139-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Janos Kerner
- NutritionCase Western Reserve University10900 Euclid Ave.ClevelandOhio44106
| | - Paul Minkler
- Medical Research 151WVA Medical Center10701 East BoulevardClevelandOhio44106
| | - Charles Hoppel
- Pharmacology and MedicineCase Western Reserve UniversityVA Medical Center10900 Euclid Ave.ClevelandOhio44106
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39
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King KL, Young ME, Vazquez E, Kerner J, Hoppel CL, Stanley WC. Effects of PPARalpha activation on mitochondrial function in the heart. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a315-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kristen L King
- Physiology and BiophysicsCase Western Reserve University10900 Euclid AveClevelandOH44106‐4970
| | - Martin E Young
- Department of PediatricsBaylor College of Medicine1100 Bates St.HoustonTX77030
| | | | - Janos Kerner
- NutritionCase Western Reserve University10900 Euclid AveClevelandOH44106
| | | | - William C Stanley
- Physiology and BiophysicsCase Western Reserve University10900 Euclid AveClevelandOH44106‐4970
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40
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Sher RB, Aoyama C, Huebsch KA, Ji S, Kerner J, Yang Y, Frankel WN, Hoppel CL, Wood PA, Vance DE, Cox GA. A Rostrocaudal Muscular Dystrophy Caused by a Defect in Choline Kinase Beta, the First Enzyme in Phosphatidylcholine Biosynthesis. J Biol Chem 2006; 281:4938-48. [PMID: 16371353 DOI: 10.1074/jbc.m512578200] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Muscular dystrophies include a diverse group of genetically heterogeneous disorders that together affect 1 in 2000 births worldwide. The diseases are characterized by progressive muscle weakness and wasting that lead to severe disability and often premature death. Rostrocaudal muscular dystrophy (rmd) is a new recessive mouse mutation that causes a rapidly progressive muscular dystrophy and a neonatal forelimb bone deformity. The rmd mutation is a 1.6-kb intragenic deletion within the choline kinase beta (Chkb) gene, resulting in a complete loss of CHKB protein and enzymatic activity. CHKB is one of two mammalian choline kinase (CHK) enzymes (alpha and beta) that catalyze the phosphorylation of choline to phosphocholine in the biosynthesis of the major membrane phospholipid phosphatidylcholine. While mutant rmd mice show a dramatic decrease of CHK activity in all tissues, the dystrophy is only evident in skeletal muscle tissues in an unusual rostral-to-caudal gradient. Minor membrane disruption similar to dysferlinopathies suggest that membrane fusion defects may underlie this dystrophy, because severe membrane disruptions are not evident as determined by creatine kinase levels, Evans Blue infiltration, and unaltered levels of proteins in the dystrophin-glycoprotein complex. The rmd mutant mouse offers the first demonstration of a defect in a phospholipid biosynthetic enzyme causing muscular dystrophy, representing a unique model for understanding mechanisms of muscle degeneration.
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MESH Headings
- Animals
- Blotting, Northern
- Carnitine O-Palmitoyltransferase/metabolism
- Catalysis
- Cell Membrane/metabolism
- Cholesterol/metabolism
- Choline Kinase/genetics
- Choline Kinase/physiology
- Chromosome Mapping
- Coloring Agents/pharmacology
- Creatine Kinase/metabolism
- Crosses, Genetic
- Dystrophin/metabolism
- Evans Blue/pharmacology
- Female
- Genotype
- Glycoproteins/metabolism
- Immunoblotting
- Lipids/chemistry
- Liver/metabolism
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Transgenic
- Microscopy, Electron
- Microscopy, Fluorescence
- Mitochondria/metabolism
- Models, Genetic
- Muscle Proteins/ultrastructure
- Muscle, Skeletal/ultrastructure
- Muscles/pathology
- Muscular Dystrophy, Animal/enzymology
- Muscular Dystrophy, Animal/pathology
- Mutation
- Phenotype
- Phosphatidylcholines/chemistry
- Physical Chromosome Mapping
- Recombination, Genetic
- Sarcolemma/ultrastructure
- Time Factors
- Triglycerides/metabolism
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Affiliation(s)
- Roger B Sher
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
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41
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Abstract
Carnitine status in humans is reported to vary according to body composition, gender, and diet. Plasma carnitine concentration positively correlates with the dietary intake of carnitine. The content of carnitine in foodstuff is based on old and inadequate methodology. Nevertheless, dietary carnitine is important. The molecular biology of the enzymes of carnitine biosynthesis has recently been accomplished. Carnitine biosynthesis requires pathways in different tissues and is an efficient system. Overall biosynthesis is determined by the availability of trimethyllysine from tissue proteins. Carnitine deficiency resulting from a defect in biosynthesis has yet to be reported. The role of carnitine in long-chain fatty acid oxidation is well defined. Recent evidence supports a role for the voltage-dependent anion channel in the transport of acyl-CoAs through the mitochondrial outer membrane. The mitochondrial outer membrane carnitine palmitoyltransferase-I in liver can be phosphorylated and when phosphorylated the sensitivity to malonyl-CoA is greatly decreased. This may explain the change in sensitivity of liver carnitine palmitoyltransferase-I observed during fasting and diabetes. Recently reported data clarify the role of carnitine and the carnitine transport system in the interplay between peroxisomes and mitochondrial fatty acid oxidation. Lastly, the buffering of the acyl-CoA/CoA coupled by carnitine reflects intracellular metabolism. This mass action effect underlies the use of carnitine as a therapeutic agent. In summary, these new observations help to further our understanding of the molecular aspects of carnitine in medicine.
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Affiliation(s)
- Alison Steiber
- Department of Nutrition, Case Western Reserve University, Medical Research Service, Cleveland, OH 44106, USA
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42
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Nyman LR, Cox KB, Hoppel CL, Kerner J, Barnoski BL, Hamm DA, Tian L, Schoeb TR, Wood PA. Homozygous carnitine palmitoyltransferase 1a (liver isoform) deficiency is lethal in the mouse. Mol Genet Metab 2005; 86:179-87. [PMID: 16169268 DOI: 10.1016/j.ymgme.2005.07.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 07/23/2005] [Accepted: 07/26/2005] [Indexed: 11/27/2022]
Abstract
To better understand carnitine palmitoyltransferase 1a (liver isoform, gene=Cpt-1a, protein=CPT-1a) deficiency in human disease, we developed a gene knockout mouse model. We used a replacement gene targeting strategy in ES cells that resulted in the deletion of exons 11-18, thus producing a null allele. Homozygous deficient mice (CPT-1a -/-) were not viable. There were no CPT-1a -/- pups, embryos or fetuses detected from day 10 of gestation to term. FISH analysis demonstrated targeting vector recombination at the expected single locus on chromosome 19. The inheritance pattern from heterozygous matings was skewed in both C57BL/6NTac, 129S6/SvEvTac (B6;129 mixed) and 129S6/SvEvTac (129 coisogenic) genetic backgrounds biased toward CPT-1a +/- mice (>80%). There was no sex preference with regard to germ-line transmission of the mutant allele. CPT-1a +/- mice had decreased Cpt-1a mRNA expression in liver, heart, brain, testis, kidney, and white fat. This resulted in 54.7% CPT-1 activity in liver from CPT-1a +/- males but no significant difference in females as compared to CPT-1a +/+ controls. CPT-1a +/- mice showed no fatty change in liver and were cold tolerant. Fasting free fatty acid concentrations were significantly elevated, while blood glucose concentrations were significantly lower in 6-week-old CPT-1a +/- mice compared to controls. Although the homozygous mutants were not viable, we did find some aspects of haploinsufficiency in the CPT-1a +/- mutants, which will make them an important mouse model for studying the role of CPT-1a in human disease.
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Affiliation(s)
- Lara R Nyman
- Department of Genetics, University of Alabama at Birmingham, USA
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43
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44
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King KL, Okere IC, Sharma N, Dyck JRB, Reszko AE, McElfresh TA, Kerner J, Chandler MP, Lopaschuk GD, Stanley WC. Regulation of cardiac malonyl-CoA content and fatty acid oxidation during increased cardiac power. Am J Physiol Heart Circ Physiol 2005; 289:H1033-7. [PMID: 15821035 DOI: 10.1152/ajpheart.00210.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myocardial fatty acid oxidation is regulated by carnitine palmitoyltransferase I (CPT I), which is inhibited by malonyl-CoA. Increased cardiac power causes a fall in malonyl-CoA content and accelerated fatty acid oxidation; however, the mechanism for the decrease in malonyl-CoA is unclear. Malonyl-CoA is formed by acetyl-CoA carboxylase (ACC) and degraded by malonyl-CoA decarboxylase (MCD); thus a fall in malonyl-CoA could be due to activation of MCD, inhibition of ACC, or both. This study assessed the effects of increased cardiac power on malonyl-CoA content and ACC and MCD activities. Anesthetized pigs were studied under control conditions and during increased cardiac power in response to dobutamine infusion and aortic constriction alone, under hyperglycemic conditions, or with the CPT I inhibitor oxfenicine. An increase in cardiac power was accompanied by increased myocardial O(2) consumption, decreased malonyl-CoA concentration, and increased fatty acid oxidation. There were no differences among groups in activity of ACC or AMP-activated protein kinase (AMPK), which physiologically inhibits ACC. There also were no differences in V(max) or K(m) of MCD. Previous studies have demonstrated that AMPK can be inhibited by protein kinase B (PKB); however, PKB was activated by dobutamine and the elevated insulin that accompanied hyperglycemia, but there was no effect on AMPK activity. In conclusion, the fall in malonyl-CoA and increase in fatty acid oxidation that occur with increased cardiac work were not due to inhibition of ACC or activation of MCD, suggesting alternative regulatory mechanisms for the work-induced decrease in malonyl-CoA concentration.
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Affiliation(s)
- Kristen L King
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106-4970, USA
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45
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Minkler PE, Kerner J, North KN, Hoppel CL. Quantitation of long-chain acylcarnitines by HPLC/fluorescence detection: application to plasma and tissue specimens from patients with carnitine palmitoyltransferase-II deficiency. Clin Chim Acta 2005; 352:81-92. [PMID: 15653102 DOI: 10.1016/j.cccn.2004.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2003] [Revised: 02/03/2004] [Accepted: 02/04/2004] [Indexed: 01/10/2023]
Abstract
BACKGROUND Carnitine palmitoyltransferase-II deficiency (CPT-II deficiency) is a rare disorder of lipid metabolism, in which the accumulation of long-chain acylcarnitines is a diagnostic marker. HPLC with fluorescence detection is an attractive analysis method due to its favorable combination of sensitivity, specificity, ease of analysis and minimal capital equipment costs. METHODS Long-chain acylcarnitines were isolated from tissue homogenates (0.5-2 mg wet weight) or plasma (50 microl) using silica gel columns and derivatized with 2-(2,3-naphthalimino)ethyl trifluoromethanesulfonate. Quantitation was by HPLC and fluorescence detection with standard curves (0.0-5.0 nmol/ml) for myristoyl-, palmitoleoyl-, palmitoyl-, oleoyl- and stearoylcarnitine using heptadecanoylcarnitine as the internal standard. RESULTS Significantly greater amounts of long-chain acylcarnitines were quantified in patients with CPT-II deficiency when compared to controls; e.g. (nmol/ml in patient plasma, controls mean+/-standard deviation): myristoylcarnitine (0.3, not detectable), palmitoleoylcarnitine (0.5, 0.1+/-0.1), palmitoylcarnitine (0.9, 0.1+/-0.0), oleoylcarnitine (3.0, 0.2+/-0.1), stearoylcarnitine (0.4, not detectable). CONCLUSIONS This method can be used to quantitate long-chain acylcarnitines, illustrating their accumulation in CPT-II deficiency. The analysis was accomplished using inexpensive and widely available instrumentation and is appropriate for research investigators who require precise quantitation of long-chain acylcarnitines in complex biological samples.
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Affiliation(s)
- Paul E Minkler
- Medical Research Service, Louis Stokes Department of Veterans Affairs Medical Center, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
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46
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Minkler PE, Anderson VE, Maiti NC, Kerner J, Hoppel CL. Isolation and identification of two isomeric forms of malonyl-coenzyme A in commercial malonyl-coenzyme A. Anal Biochem 2005; 328:203-9. [PMID: 15113698 DOI: 10.1016/j.ab.2004.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Indexed: 10/26/2022]
Abstract
Two isomers of malonyl-coenzyme A (malonyl-CoA) were detected in a commercial preparation of malonyl-CoA. These compounds were separated by preparative high-performance liquid chromatography (HPLC) and characterized by HPLC/ultraviolet (UV)/mass spectrometry. Both compounds had a UV absorbance maximum at 259-260 nm. Both compounds underwent negative electrospray ionization to produce a [M-H](-)quasi-molecular ion at m/z 852 and both compounds underwent collision-induced dissociation to produce a characteristic fragment at m/z 808, all consistent with the structure of malonyl-CoA. Nuclear magnetic resonance spectrometry showed that the two chromatographically distinguishable malonyl-CoAs are structural isomers: the major component is the naturally occurring malonyl-CoA and the contaminant is 3'-dephospho- 2'-phospho-coenzyme A.
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Affiliation(s)
- Paul E Minkler
- Medical Research Service, Louis Stokes Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA
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47
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Chandler MP, Kerner J, Huang H, Vazquez E, Reszko A, Martini WZ, Hoppel CL, Imai M, Rastogi S, Sabbah HN, Stanley WC. Moderate severity heart failure does not involve a downregulation of myocardial fatty acid oxidation. Am J Physiol Heart Circ Physiol 2004; 287:H1538-43. [PMID: 15191896 DOI: 10.1152/ajpheart.00281.2004] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent human and animal studies have demonstrated that in severe end-stage heart failure (HF), the cardiac muscle switches to a more fetal metabolic phenotype, characterized by downregulation of free fatty acid (FFA) oxidation and an enhancement of glucose oxidation. The goal of this study was to examine myocardial substrate metabolism in a model of moderate coronary microembolization-induced HF. We hypothesized that during well-compensated HF, FFA oxidation would predominate as opposed to a more fetal metabolic phenotype of greater glucose oxidation. Cardiac substrate uptake and oxidation were measured in normal dogs ( n = 8) and in dogs with microembolization-induced HF ( n = 18, ejection fraction = 28%) by infusing three isotopic tracers ([9,10-3H]oleate, [U-14C]glucose, and [1-13C]lactate) in anesthetized open-chest animals. There were no differences in myocardial substrate metabolism between the two groups. The total activity of pyruvate dehydrogenase, the key enzyme regulating myocardial pyruvate oxidation (and hence glucose and lactate oxidation) was not affected by HF. We did not observe any difference in the activity of carnitine palmitoyl transferase I (CPT-I) and its sensitivity to inhibition by malonyl-CoA between groups; however, malonyl-CoA content was decreased by 22% with HF, suggesting less in vivo inhibition of CPT-I activity. The differences in malonyl-CoA content cannot be explained by changes in the Michaelis-Menten constant and maximal velocity for malonyl-CoA decarboxylase because neither were affected by HF. These results support the concept that there is no decrease in fatty acid oxidation during compensated HF and that the downregulation of fatty acid oxidation enzymes and the switch to carbohydrate oxidation observed in end-stage HF is only a late-stage phenomemon.
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Affiliation(s)
- Margaret P Chandler
- Dept. of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4970, USA
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48
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Kerner J, Distler AM, Minkler P, Parland W, Peterman SM, Hoppel CL. Phosphorylation of rat liver mitochondrial carnitine palmitoyltransferase-I: effect on the kinetic properties of the enzyme. J Biol Chem 2004; 279:41104-13. [PMID: 15247243 DOI: 10.1074/jbc.m406570200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hepatic carnitine palmitoyltransferase-I (CPT-IL) isolated from mitochondrial outer membranes obtained in the presence of protein phosphatase inhibitors is readily recognized by phosphoamino acid antibodies. Mass spectrometric analysis of CPT-IL tryptic digests revealed the presence of three phosphopeptides including one with a protein kinase CKII (CKII) consensus site. Incubation of dephosphorylated outer membranes with protein kinases and [gamma-32P]ATP resulted in radiolabeling of CPT-I only by CKII. Using mass spectrometry, only one region of phosphorylation was detected in CPT-I isolated from CKII-treated mitochondria. The sequence of the peptide and position of phosphorylated amino acids have been determined unequivocally as FpSSPETDpSHRFGK (residues 740-752). Furthermore, incubation of dephosphorylated outer membranes with CKII and unlabeled ATP led to increased catalytic activity and rendered malonyl-CoA inhibition of CPT-I from competitive to uncompetitive. These observations identify a new mechanism for regulation of hepatic CPT-I by phosphorylation.
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Affiliation(s)
- Janos Kerner
- Department of Nutrition, Biochemistry, and Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Affiliation(s)
- Joseph P Sterk
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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Abstract
Malonyl-CoA decarboxylase is the main route for the disposal of malonyl-CoA, the key metabolite in the regulation of mitochondrial fatty acid oxidation. We have developed a simple and sensitive radiochemical assay to determine malonyl-CoA decarboxylase activity. The decarboxylation of [2-14C]malonyl-CoA produces [2-14C]acetyl-CoA, which is converted to [2-14C]acetylcarnitine in the presence of excess L-carnitine and carnitine acetyltransferase. The positively charged radiolabeled product, acetylcarnitine, is separated from negatively charged excess radiolabeled substrate and the radioactivity measured by scintillation counting. Measurement of malonyl-CoA decarboxylase activities with this method gives values comparable to those obtained with assays currently in use, but has the advantage of being simpler and less labor intensive. We have applied this assay to rat skeletal muscle of different fiber-type composition and to rat heart. Malonyl-CoA decarboxylase activity (mU/g wet wt) correlates with the oxidative capacity of the muscles, being lowest in type IIb fibers (42.7 +/- 3.0) and highest in heart (1071.4 +/- 260), with intermediate activity in type IIa fibers (150.7 +/- 4.3) and type I fibers (107.8 +/- 7.6). Studies on subcellular distribution of malonyl-CoA decarboxylase activity in rat heart and rat skeletal muscle show that approximately 50 and 65% is localized to mitochondria, while 50 and 35% of the activity is extramitochondrial.
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Affiliation(s)
- Janos Kerner
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA
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