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Dratch L, Bardakjian TM, Johnson K, Babaian N, Gonzalez-Alegre P, Elman L, Quinn C, Guo MH, Scherer SS, Amado DA. The Importance of Offering Exome or Genome Sequencing in Adult Neuromuscular Clinics. BIOLOGY 2024; 13:93. [PMID: 38392311 PMCID: PMC10886886 DOI: 10.3390/biology13020093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/24/2024]
Abstract
Advances in gene-specific therapeutics for patients with neuromuscular disorders (NMDs) have brought increased attention to the importance of genetic diagnosis. Genetic testing practices vary among adult neuromuscular clinics, with multi-gene panel testing currently being the most common approach; follow-up testing using broad-based methods, such as exome or genome sequencing, is less consistently offered. Here, we use five case examples to illustrate the unique ability of broad-based testing to improve diagnostic yield, resulting in identification of SORD-neuropathy, HADHB-related disease, ATXN2-ALS, MECP2 related progressive gait decline and spasticity, and DNMT1-related cerebellar ataxia, deafness, narcolepsy, and hereditary sensory neuropathy type 1E. We describe in each case the technological advantages that enabled identification of the causal gene, and the resultant clinical and personal implications for the patient, demonstrating the importance of offering exome or genome sequencing to adults with NMDs.
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Affiliation(s)
- Laynie Dratch
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tanya M Bardakjian
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Sarepta Therapeutics Inc., Cambridge, MA 02142, USA
| | - Kelsey Johnson
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nareen Babaian
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pedro Gonzalez-Alegre
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Spark Therapeutics, Inc., Philadelphia, PA 19104, USA
| | - Lauren Elman
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Colin Quinn
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael H Guo
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Steven S Scherer
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Defne A Amado
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Odendaal C, Jager EA, Martines ACMF, Vieira-Lara MA, Huijkman NCA, Kiyuna LA, Gerding A, Wolters JC, Heiner-Fokkema R, van Eunen K, Derks TGJ, Bakker BM. Personalised modelling of clinical heterogeneity between medium-chain acyl-CoA dehydrogenase patients. BMC Biol 2023; 21:184. [PMID: 37667308 PMCID: PMC10478272 DOI: 10.1186/s12915-023-01652-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 06/21/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Monogenetic inborn errors of metabolism cause a wide phenotypic heterogeneity that may even differ between family members carrying the same genetic variant. Computational modelling of metabolic networks may identify putative sources of this inter-patient heterogeneity. Here, we mainly focus on medium-chain acyl-CoA dehydrogenase deficiency (MCADD), the most common inborn error of the mitochondrial fatty acid oxidation (mFAO). It is an enigma why some MCADD patients-if untreated-are at risk to develop severe metabolic decompensations, whereas others remain asymptomatic throughout life. We hypothesised that an ability to maintain an increased free mitochondrial CoA (CoASH) and pathway flux might distinguish asymptomatic from symptomatic patients. RESULTS We built and experimentally validated, for the first time, a kinetic model of the human liver mFAO. Metabolites were partitioned according to their water solubility between the bulk aqueous matrix and the inner membrane. Enzymes are also either membrane-bound or in the matrix. This metabolite partitioning is a novel model attribute and improved predictions. MCADD substantially reduced pathway flux and CoASH, the latter due to the sequestration of CoA as medium-chain acyl-CoA esters. Analysis of urine from MCADD patients obtained during a metabolic decompensation showed an accumulation of medium- and short-chain acylcarnitines, just like the acyl-CoA pool in the MCADD model. The model suggested some rescues that increased flux and CoASH, notably increasing short-chain acyl-CoA dehydrogenase (SCAD) levels. Proteome analysis of MCADD patient-derived fibroblasts indeed revealed elevated levels of SCAD in a patient with a clinically asymptomatic state. This is a rescue for MCADD that has not been explored before. Personalised models based on these proteomics data confirmed an increased pathway flux and CoASH in the model of an asymptomatic patient compared to those of symptomatic MCADD patients. CONCLUSIONS We present a detailed, validated kinetic model of mFAO in human liver, with solubility-dependent metabolite partitioning. Personalised modelling of individual patients provides a novel explanation for phenotypic heterogeneity among MCADD patients. Further development of personalised metabolic models is a promising direction to improve individualised risk assessment, management and monitoring for inborn errors of metabolism.
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Affiliation(s)
- Christoff Odendaal
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Emmalie A Jager
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
- Section of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Anne-Claire M F Martines
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Marcel A Vieira-Lara
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Nicolette C A Huijkman
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Ligia A Kiyuna
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Albert Gerding
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
- Department of Laboratory Medicine, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Justina C Wolters
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Karen van Eunen
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Terry G J Derks
- Section of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.
| | - Barbara M Bakker
- Laboratory of Paediatrics, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.
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3
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Gaston G, Babcock S, Ryals R, Elizondo G, DeVine T, Wafai D, Packwood W, Holden S, Raber J, Lindner JR, Pennesi ME, Harding CO, Gillingham MB. A G1528C Hadha knock-in mouse model recapitulates aspects of human clinical phenotypes for long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Commun Biol 2023; 6:890. [PMID: 37644104 PMCID: PMC10465608 DOI: 10.1038/s42003-023-05268-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 08/21/2023] [Indexed: 08/31/2023] Open
Abstract
Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) is a fatty acid oxidation disorder (FAOD) caused by a pathogenic variant, c.1528 G > C, in HADHA encoding the alpha subunit of trifunctional protein (TFPα). Individuals with LCHADD develop chorioretinopathy and peripheral neuropathy not observed in other FAODs in addition to the more ubiquitous symptoms of hypoketotic hypoglycemia, rhabdomyolysis and cardiomyopathy. We report a CRISPR/Cas9 generated knock-in murine model of G1528C in Hadha that recapitulates aspects of the human LCHADD phenotype. Homozygous pups are less numerous than expected from Mendelian probability, but survivors exhibit similar viability with wildtype (WT) littermates. Tissues of LCHADD homozygotes express TFPα protein, but LCHADD mice oxidize less fat and accumulate plasma 3-hydroxyacylcarnitines compared to WT mice. LCHADD mice exhibit lower ketones with fasting, exhaust earlier during treadmill exercise and develop a dilated cardiomyopathy compared to WT mice. In addition, LCHADD mice exhibit decreased visual performance, decreased cone function, and disruption of retinal pigment epithelium. Neurological function is affected, with impaired motor function during wire hang test and reduced open field activity. The G1528C knock-in mouse exhibits a phenotype similar to that observed in human patients; this model will be useful to explore pathophysiology and treatments for LCHADD in the future.
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Affiliation(s)
- Garen Gaston
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Shannon Babcock
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Renee Ryals
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - Gabriela Elizondo
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Tiffany DeVine
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Dahlia Wafai
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - William Packwood
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Sarah Holden
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - Jacob Raber
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
- Departments of Neurology and Radiation Medicine, Oregon Health and Science University, Portland, OR, USA
- Division of Neuroscience, Oregon National Primate Research Center (ONPRC), Oregon Health and Science University, Portland, OR, USA
| | - Jonathan R Lindner
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Cardiovascular Division, University of Virginia Medical Center, Charlottesville, VA, USA
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - Cary O Harding
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Melanie B Gillingham
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA.
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Mitochondrial Dysfunction and Acute Fatty Liver of Pregnancy. Int J Mol Sci 2022; 23:ijms23073595. [PMID: 35408956 PMCID: PMC8999031 DOI: 10.3390/ijms23073595] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 01/27/2023] Open
Abstract
The liver is one of the richest organs in mitochondria, serving as a hub for key metabolic pathways such as β-oxidation, the tricarboxylic acid (TCA) cycle, ketogenesis, respiratory activity, and adenosine triphosphate (ATP) synthesis, all of which provide metabolic energy for the entire body. Mitochondrial dysfunction has been linked to subcellular organelle dysfunction in liver diseases, particularly fatty liver disease. Acute fatty liver of pregnancy (AFLP) is a life-threatening liver disorder unique to pregnancy, which can result in serious maternal and fetal complications, including death. Pregnant mothers with this disease require early detection, prompt delivery, and supportive maternal care. AFLP was considered a mysterious illness and though its pathogenesis has not been fully elucidated, molecular research over the past two decades has linked AFLP to mitochondrial dysfunction and defects in fetal fatty-acid oxidation (FAO). Due to deficient placental and fetal FAO, harmful 3-hydroxy fatty acid metabolites accumulate in the maternal circulation, causing oxidative stress and microvesicular fatty infiltration of the liver, resulting in AFLP. In this review, we provide an overview of AFLP and mitochondrial FAO followed by discussion of how altered mitochondrial function plays an important role in the pathogenesis of AFLP.
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5
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Hitit M, Özbek M, Ayaz-Guner S, Guner H, Oztug M, Bodu M, Kirbas M, Bulbul B, Bucak MN, Ataman MB, Memili E, Kaya A. Proteomic fertility markers in ram sperm. Anim Reprod Sci 2021; 235:106882. [PMID: 34823050 DOI: 10.1016/j.anireprosci.2021.106882] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 01/26/2023]
Abstract
Precise estimation of ram fertility is important for sheep farming to sustain reproduction efficiency and profitability of production. There, however, is no conventional method to accurately predict ram fertility. The objective of this study, therefore, was to ascertain proteomic profiles of ram sperm having contrasting fertility phenotypes. Mature rams (n = 66) having greater pregnancy rates than average (89.4 ± 7.2%) were assigned into relatively-greater fertility (GF; n = 31; 94.5 ± 2.8%) whereas those with less-than-average pregnancy rates were assigned into a lesser-fertility (LF; n = 25; 83.1 ± 5.73%; P = 0.028) group. Sperm samples from the outlier greatest- and least-fertility rams (n = 6, pregnancy rate; 98.4 ± 1.8% and 76.1 ± 3.9%) were used for proteomics assessments utilizing Label-free LC-MS/MS. A total of 997 proteins were identified, and among these, 840 were shared by both groups, and 57 and 93 were unique to GF and LF, respectively. Furthermore, 190 differentially abundant proteins were identified; the abundance of 124 was larger in GF while 66 was larger in LF rams. The GF ram sperm had 79 GO/pathway terms in ten major biological networks while there were 47 GO/pathway terms in six biological networks in sperm of LF rams. Accordingly, differential abundances of sperm proteins between sperm of GF and LF rams were indicative of functional implications of sperm proteome on male fertility. The results of this study emphasize there are potential protein markers for evaluation of semen quality and estimation of ram sperm fertilizing capacity.
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Affiliation(s)
- Mustafa Hitit
- Department of Genetics, Faculty of Veterinary Medicine, Kastamonu University, Kastamonu, Turkey
| | - Mehmet Özbek
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Mehmet Akif Ersoy University, Burdur, Turkey
| | - Serife Ayaz-Guner
- Department of Molecular Biology and Genetics, Faculty of Life and Natural Science, Abdullah Gül University, Kayseri, Turkey
| | - Huseyin Guner
- Department of Molecular Biology and Genetics, Faculty of Life and Natural Science, Abdullah Gül University, Kayseri, Turkey
| | - Merve Oztug
- National Metrology Institute, TUBITAK UME, Kocaeli, Turkey
| | - Mustafa Bodu
- Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey
| | - Mesut Kirbas
- Bahri Dagdas International Agricultural Research Institute, Konya, Turkey
| | - Bulent Bulbul
- Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Mustafa Numan Bucak
- Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey
| | - Mehmet Bozkurt Ataman
- Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey
| | - Erdoğan Memili
- Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS, United States; Cooperative Agricultural Research Center, College of Agriculture and Human Sciences, Prairie View A&M University, Prairie View, TX, United States.
| | - Abdullah Kaya
- Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey.
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6
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Dagher R, Massie R, Gentil BJ. MTP deficiency caused by HADHB mutations: Pathophysiology and clinical manifestations. Mol Genet Metab 2021; 133:1-7. [PMID: 33744096 DOI: 10.1016/j.ymgme.2021.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/17/2022]
Abstract
Mutations in the HADHB gene lead to Mitochondrial Trifunctional Protein (MTP) deficiency. MTP deficiency is a rare autosomal recessive disorder affecting long-chain fatty acid oxidation. Patients affected by MTP deficiency are unable to metabolize long-chain fatty-acids and suffer a variety of symptoms exacerbated during fasting. The three phenotypes associated with complete MTP deficiency are an early-onset cardiomyopathy and early death, an intermediate form with recurrent hypoketotic hypoglycemia and a sensorimotor neuropathy with episodic rhabdomyolysis with small amount of residual enzyme activities. This review aims to discuss the pathophysiological mechanisms and clinical manifestations of each phenotype, which appears different and linked to HADHB expression levels. Notably, the pathophysiology of the sensorimotor neuropathy is relatively unknown and we provide a hypothesis on the qualitative aspect of the role of acylcarnitine buildup in Schwann cells in MTP deficiency patients. We propose that acylcarnitine may exit the Schwann cell and alter membrane properties of nearby axons leading to axonal degeneration based on recent findings in different metabolic disorders.
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Affiliation(s)
- Robin Dagher
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC H3A 2B4, Canada
| | - Rami Massie
- Department of Neurology/Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada
| | - Benoit J Gentil
- Department of Kinesiology and Physical Education, McGill University, Montreal, QC H3A 2B4, Canada; Department of Neurology/Neurosurgery, McGill University, Montreal, QC H3A 2B4, Canada.
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7
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Tan C, Liu X, Peng W, Wang H, Zhou W, Jiang J, Wei X, Mo L, Chen Y, Chen L. Seizure-induced impairment in neuronal ketogenesis: Role of zinc-α2-glycoprotein in mitochondria. J Cell Mol Med 2020; 24:6833-6845. [PMID: 32340079 PMCID: PMC7299723 DOI: 10.1111/jcmm.15337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 01/11/2020] [Accepted: 04/12/2020] [Indexed: 12/14/2022] Open
Abstract
Ketone bodies (KBs) were known to suppress seizure. Untraditionally, neurons were recently reported to utilize fatty acids and produce KBs, but the effect of seizure on neuronal ketogenesis has not been researched. Zinc‐α2‐glycoprotein (ZAG) was reported to suppress seizure via unclear mechanism. Interestingly, ZAG was involved in fatty acid β‐oxidation and thus may exert anti‐epileptic effect by promoting ketogenesis. However, this promotive effect of ZAG on neuronal ketogenesis has not been clarified. In this study, we performed immunoprecipitation and mass spectrometry to identify potential interaction partners with ZAG. The mechanisms of how ZAG translocated into mitochondria were determined by quantitative coimmunoprecipitation after treatment with apoptozole, a heat shock cognate protein 70 (HSC70) inhibitor. ZAG level was modulated by lentivirus in neurons or adeno‐associated virus in rat brains. Seizure models were induced by magnesium (Mg2+)‐free artificial cerebrospinal fluid in neurons or intraperitoneal injection of pentylenetetrazole kindling in rats. Ketogenesis was determined by cyclic thio‐NADH method in supernatant of neurons or brain homogenate. The effect of peroxisome proliferator–activated receptor γ (PPARγ) on ZAG expression was examined by Western blot, quantitative real‐time polymerase chain reaction (qRT‐PCR) and chromatin immunoprecipitation qRT‐PCR. We found that seizure induced ketogenesis deficiency via a ZAG‐dependent mechanism. ZAG entered mitochondria through a HSC70‐dependent mechanism, promoted ketogenesis by binding to four β‐subunits of long‐chain L‐3‐hydroxyacyl‐CoA dehydrogenase (HADHB) and alleviated ketogenesis impairment in a neuronal seizure model and pentylenetetrazole‐kindled epileptic rats. Additionally, PPARγ activation up‐regulated ZAG expression by binding to promoter region of AZGP1 gene and promoted ketogenesis through a ZAG‐dependent mechanism.
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Affiliation(s)
- Changhong Tan
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xi Liu
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wuxue Peng
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hui Wang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wen Zhou
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jin Jiang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xin Wei
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lijuan Mo
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yangmei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lifen Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
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8
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Nakama M, Sasai H, Kubota M, Hasegawa Y, Fujiki R, Okuyama T, Ohara O, Fukao T. Novel HADHB mutations in a patient with mitochondrial trifunctional protein deficiency. Hum Genome Var 2020; 7:10. [PMID: 32257295 PMCID: PMC7118068 DOI: 10.1038/s41439-020-0097-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/07/2020] [Accepted: 02/21/2020] [Indexed: 01/02/2023] Open
Abstract
We encountered a patient with mitochondrial trifunctional protein deficiency in whom the corresponding mutations were not identified by a DNA panel for newborn screening for targeted diseases. After diagnosis confirmation by an enzyme assay and immunoblotting using the autopsied liver, the re-evaluation of the panel data indicated a heterozygous deletion of exons 6-9 that was later confirmed at the genomic level. cDNA analysis also identified exonization of the 5' region of intron 9 caused by a deep intronic mutation, c.811 + 82A>G.
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Affiliation(s)
- Mina Nakama
- Clinical Genetics Center, Gifu University Hospital, Gifu, Japan
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Hideo Sasai
- Clinical Genetics Center, Gifu University Hospital, Gifu, Japan
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Mitsuru Kubota
- Department of General Pediatrics & Interdisciplinary Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Yuki Hasegawa
- Department of Pediatrics, Faculty of Medicine, Shimane University, Shimane, Japan
| | - Ryoji Fujiki
- Department of Applied Genomics, Kazusa DNA Research Institute, Chiba, Japan
| | - Torayuki Okuyama
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Osamu Ohara
- Department of Applied Genomics, Kazusa DNA Research Institute, Chiba, Japan
| | - Toshiyuki Fukao
- Clinical Genetics Center, Gifu University Hospital, Gifu, Japan
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Japan
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9
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Pennisi EM, Garibaldi M, Antonini G. Lipid Myopathies. J Clin Med 2018; 7:E472. [PMID: 30477112 PMCID: PMC6306737 DOI: 10.3390/jcm7120472] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 02/06/2023] Open
Abstract
Disorders of lipid metabolism affect several tissues, including skeletal and cardiac muscle tissues. Lipid myopathies (LM) are rare multi-systemic diseases, which most often are due to genetic defects. Clinically, LM can have acute or chronic clinical presentation. Disease onset can occur in all ages, from early stages of life to late-adult onset, showing with a wide spectrum of clinical symptoms. Muscular involvement can be fluctuant or stable and can manifest as fatigue, exercise intolerance and muscular weakness. Muscular atrophy is rarely present. Acute muscular exacerbations, resulting in rhabdomyolysis crisis are triggered by several factors. Several classifications of lipid myopathies have been proposed, based on clinical involvement, biochemical defect or histopathological findings. Herein, we propose a full revision of all the main clinical entities of lipid metabolism disorders with a muscle involvement, also including some those disorders of fatty acid oxidation (FAO) with muscular symptoms not included among previous lipid myopathies classifications.
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Affiliation(s)
- Elena Maria Pennisi
- Unit of Neuromuscular Disorders, Neurology, San Filippo Neri Hospital, 00135 Rome, Italy.
| | - Matteo Garibaldi
- Unit of Neuromuscular Diseases, Department of Neurology, Mental Health and Sensory Organs (NESMOS), SAPIENZA University of Rome, Sant' Andrea Hospital, 00189 Rome, Italy.
| | - Giovanni Antonini
- Unit of Neuromuscular Diseases, Department of Neurology, Mental Health and Sensory Organs (NESMOS), SAPIENZA University of Rome, Sant' Andrea Hospital, 00189 Rome, Italy.
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10
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Abstract
The mitochondrial trifunctional protein (TFP) catalyzes three reactions in the fatty acid β-oxidation process. Mutations in the two TFP subunits cause mitochondrial trifunctional protein deficiency and acute fatty liver of pregnancy that can lead to death. Here we report a 4.2-Å cryo-electron microscopy α2β2 tetrameric structure of the human TFP. The tetramer has a V-shaped architecture that displays a distinct assembly compared with the bacterial TFPs. A concave surface of the TFP tetramer interacts with the detergent molecules in the structure, suggesting that this region is involved in associating with the membrane. Deletion of a helical hairpin in TFPβ decreases its binding to the liposomes in vitro and reduces its membrane targeting in cells. Our results provide the structural basis for TFP function and have important implications for fatty acid oxidation related diseases.
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11
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Sehrawat U, Pokhriyal R, Gupta AK, Hariprasad R, Khan MI, Gupta D, Naru J, Singh SB, Mohanty AK, Vanamail P, Kumar L, Kumar S, Hariprasad G. Comparative Proteomic Analysis of Advanced Ovarian Cancer Tissue to Identify Potential Biomarkers of Responders and Nonresponders to First-Line Chemotherapy of Carboplatin and Paclitaxel. BIOMARKERS IN CANCER 2016; 8:43-56. [PMID: 26997873 PMCID: PMC4795487 DOI: 10.4137/bic.s35775] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/08/2016] [Accepted: 02/11/2016] [Indexed: 12/16/2022]
Abstract
Conventional treatment for advanced ovarian cancer is an initial debulking surgery followed by chemotherapy combination of carboplatin and paclitaxel. Despite initial high response, three-fourths of these women experience disease recurrence with a dismal prognosis. Patients with advanced-stage ovarian cancer who underwent cytoreductive surgery were enrolled and tissue samples were collected. Post surgery, these patients were started on chemotherapy and followed up till the end of the cycle. Fluorescence-based differential in-gel expression coupled with mass spectrometric analysis was used for discovery phase of experiments, and real-time polymerase chain reaction, Western blotting, and pathway analysis were performed for expression and functional validation of differentially expressed proteins. While aldehyde reductase, hnRNP, cyclophilin A, heat shock protein-27, and actin are upregulated in responders, prohibitin, enoyl-coA hydratase, peroxiredoxin, and fibrin-β are upregulated in the nonresponders. The expressions of some of these proteins correlated with increased apoptotic activity in responders and decreased apoptotic activity in nonresponders. Therefore, the proteins qualify as potential biomarkers to predict chemotherapy response.
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Affiliation(s)
- Urmila Sehrawat
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Ruchika Pokhriyal
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Ashish Kumar Gupta
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Roopa Hariprasad
- Department of Medical Oncology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Mohd Imran Khan
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Divya Gupta
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Jasmine Naru
- National Dairy Research Institute, Karnal, India
| | | | | | - Perumal Vanamail
- Department of Obstetrics and Gynecology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Lalit Kumar
- Department of Medical Oncology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Sunesh Kumar
- Department of Obstetrics and Gynecology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Gururao Hariprasad
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
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Taylor WA, Mejia EM, Mitchell RW, Choy PC, Sparagna GC, Hatch GM. Human trifunctional protein alpha links cardiolipin remodeling to beta-oxidation. PLoS One 2012; 7:e48628. [PMID: 23152787 PMCID: PMC3494688 DOI: 10.1371/journal.pone.0048628] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 10/02/2012] [Indexed: 12/19/2022] Open
Abstract
Cardiolipin (CL) is a mitochondrial membrane phospholipid which plays a key role in apoptosis and supports mitochondrial respiratory chain complexes involved in the generation of ATP. In order to facilitate its role CL must be remodeled with appropriate fatty acids. We previously identified a human monolysocardiolipin acyltransferase activity which remodels CL via acylation of monolysocardiolipin (MLCL) to CL and was identical to the alpha subunit of trifunctional protein (αTFP) lacking the first 227 amino acids. Full length αTFP is an enzyme that plays a prominent role in mitochondrial β-oxidation, and in this study we assessed the role, if any, which this metabolic enzyme plays in the remodeling of CL. Purified human recombinant αTFP exhibited acyl-CoA acyltransferase activity in the acylation of MLCL to CL with linoleoyl-CoA, oleoyl-CoA and palmitoyl-CoA as substrates. Expression of αTFP increased radioactive linoleate or oleate or palmitate incorporation into CL in HeLa cells. Expression of αTFP in Barth Syndrome lymphoblasts, which exhibit reduced tetralinoleoyl-CL, elevated linoleoyl-CoA acylation of MLCL to CL in vitro, increased mitochondrial respiratory Complex proteins and increased linoleate-containing species of CL. Knock down of αTFP in Barth Syndrome lymphoblasts resulted in greater accumulation of MLCL than those with normal αTFP levels. The results clearly indicate that the human αTFP exhibits MLCL acyltransferase activity for the resynthesis of CL from MLCL and directly links an enzyme of mitochondrial β-oxidation to CL remodeling.
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Affiliation(s)
- William A. Taylor
- Department of Pharmacology and Therapeutics, Center for Research and Treatment of Atherosclerosis, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Edgard M. Mejia
- Department of Pharmacology and Therapeutics, Center for Research and Treatment of Atherosclerosis, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ryan W. Mitchell
- Department of Pharmacology and Therapeutics, Center for Research and Treatment of Atherosclerosis, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Patrick C. Choy
- Biochemistry and Medical Genetics, Center for Research and Treatment of Atherosclerosis, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Genevieve C. Sparagna
- Department of Integrative Physiology, University of Colorado at Boulder, Boulder, Colorado, United States of America
| | - Grant M. Hatch
- Department of Pharmacology and Therapeutics, Center for Research and Treatment of Atherosclerosis, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
- Biochemistry and Medical Genetics, Center for Research and Treatment of Atherosclerosis, Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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13
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Diekman EF, Boelen CCA, Prinsen BHCMT, Ijlst L, Duran M, de Koning TJ, Waterham HR, Wanders RJA, Wijburg FA, Visser G. Necrotizing enterocolitis and respiratory distress syndrome as first clinical presentation of mitochondrial trifunctional protein deficiency. JIMD Rep 2012; 7:1-6. [PMID: 23430487 DOI: 10.1007/8904_2012_128] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 01/12/2012] [Accepted: 01/13/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Newborn screening (NBS) for long-chain 3-hydroxy acyl-CoA dehydrogenase (LCHAD) deficiency does not discriminate between isolated LCHAD deficiency, isolated long-chain keto acyl-CoA (LCKAT) deficiency and general mitochondrial trifunctional protein (MTP) deficiency. Therefore, screening for LCHAD deficiency inevitably comprises screening for MTP deficiency, which is much less amenable to treatment. Furthermore, absence of a clear classification system for these disorders is still lacking. MATERIALS AND METHODS Two newborns screened positive for LCHAD deficiency died at the age of 10 and 31 days, respectively. One due to severe necrotizing enterocolitis (NEC), cardiomyopathy and multiorgan failure and the other due to severe infant respiratory distress syndrome (IRDS) and hypertrophic cardiomyopathy. (Keto)-acylcarnitine concentration and enzymatic analysis of LCHAD and LCKAT suggested MTP deficiency in both patients. Mutation analysis revealed a homozygous HADHB c.357+5delG mutation in one patient and a homozygous splice-site HADHB mutation c.212+1G>C in the other patient.Data on enzymatic and mutation analysis of 40 patients with presumed LCHAD, LCKAT or MTP deficiency were used to design a classification to distinguish between these disorders. DISCUSSION NEC as presenting symptom in MTP deficiency has not been reported previously. High expression of long-chain fatty acid oxidation enzymes reported in lungs and gut of human foetuses suggests that the severe NEC and IRDS observed in our patients are related to the enzymatic deficiency in these organs during crucial stages of development.Furthermore, as illustrated by the cases we propose a classification system to discriminate LCHAD, LCKAT and MTP deficiency based on enzymatic analysis.
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Affiliation(s)
- Eugène F Diekman
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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14
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Zhou Z, Zhou J, Du Y. Estrogen receptor alpha interacts with mitochondrial protein HADHB and affects beta-oxidation activity. Mol Cell Proteomics 2012; 11:M111.011056. [PMID: 22375075 DOI: 10.1074/mcp.m111.011056] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
It is known that estrogen receptors can function as nuclear receptors and transcription factors in the nucleus and as signaling molecules in the plasma membrane. In addition, the localization of the receptors in mitochondria suggests that they may play important roles in mitochondria. In order to identify novel proteins that are involved in ERα-mediated actions of estrogens, we used a proteomic method that integrated affinity purification, two-dimensional gel electrophoresis, and mass spectrometry to isolate and identify cellular proteins that interact with ERα. One of the proteins identified was trifunctional protein β-subunit (HADHB), a mitochondrial protein that is required for β-oxidation of fatty acids in mitochondria. We have verified the interaction between ERα and HADHB by coimmunoprecipitation and established that ERα directly binds to HADHB by performing an in vitro binding assay. In addition, we have shown that ERα colocalizes with HADHB in the mitochondria by confocal microscopy, and the two proteins interact with each other within mitochondria by performing coimmunoprecipitation using purified mitochondria as starting materials. We have demonstrated that the expression of ERα affects HADHB activity, and a combination of 17β-estrodiol and tamoxifen affects the activity of HADHB prepared from human breast cancer cells that express ERα but not from the cells that are ERα deficient. Furthermore, we have demonstrated that 17β-estrodiol plus tamoxifen affects the association of ERα with HADHB in human cell extract. Our results suggest that HADHB is a functional molecular target of ERα in the mitochondria, and the interaction may play an important role in the estrogen-mediated lipid metabolism in animals and humans.
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Affiliation(s)
- Zhenqi Zhou
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, USA
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15
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Joost K, Ounap K, Zordania R, Uudelepp ML, Olsen RK, Kall K, Kilk K, Soomets U, Kahre T. Prevalence of Long-Chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency in Estonia. JIMD Rep 2011; 2:79-85. [PMID: 23430857 DOI: 10.1007/8904_2011_51] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/12/2011] [Accepted: 03/17/2011] [Indexed: 12/13/2022] Open
Abstract
The aim of our study was to evaluate the prevalence of long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) in the general Estonian population and among patients with symptoms suggestive of fatty acid oxidation (FAO) defects. We collected DNA from a cohort of 1,040 anonymous newborn blood spot samples. We screened these samples for the presence of the common c.1528G>C mutation in the HADHA gene. Based on the clinical suspicion of FAO defects, we screened suspected individuals since 2004 for the common c.1528G>C mutation in the HADHA gene and since 2008 in addition by tandem mass spectrometric analysis of plasma acylcarnitines. Our results showed that the carrier frequency of the c.1528G>C mutation in the Estonian population is high - 1:173. During the screening of symptomatic patients, we identified five LCHADD patients in four families. Three patients were retrospectively identified by molecular screening of the HADHA gene. One patient was homozygous for the c.1528G>C mutation in the HADHA gene, and two siblings were compound heterozygotes with HADHA genotype c.[1528G>C]+[1690-2A>G]. Among patients tested using acylcarnitine profiling, we identified two cases with an abnormal acylcarnitine profile typical to LCHADD. Molecular analysis showed homozygosity for c.1528G>C mutation. Based on a carrier frequency of 1:173 (95% Confidence Interval 1:76-1:454) and taking into account that the c.1528G>C mutation makes up 87.5% of disease alleles in Estonian LCHADD patients, the estimated prevalence of LCHADD in Estonia would be 1: 91,700.
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Affiliation(s)
- K Joost
- The Centre of Excellence for Translational Medicine, University of Tartu, Tartu, Estonia,
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16
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Rector RS, Ibdah JA. Fatty acid oxidation disorders: maternal health and neonatal outcomes. Semin Fetal Neonatal Med 2010; 15:122-8. [PMID: 19926542 DOI: 10.1016/j.siny.2009.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Mitochondrial fatty acid beta-oxidation (FAO) disorders have become an important group of inherited metabolic disorders causing serious pediatric and maternal morbidity and mortality. More than 20 defects affecting beta-oxidation have been discovered, characterized by distinct enzyme or transporter deficiencies. This growing number of FAO disorders covers a wide spectrum of phenotypes and are characterized by a wide array of clinical presentations. We discuss the major mitochondrial FAO disorders and the impact they have on maternal health and neonatal outcomes; diagnostic tools and the value of genetic screening are reviewed; and current therapeutic approaches and management strategies are discussed.
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Affiliation(s)
- R Scott Rector
- Division of Gastroenterology and Hepatology, University of Missouri-Columbia, Columbia, Missouri 65212, USA
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17
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Purevsuren J, Fukao T, Hasegawa Y, Kobayashi H, Li H, Mushimoto Y, Fukuda S, Yamaguchi S. Clinical and molecular aspects of Japanese patients with mitochondrial trifunctional protein deficiency. Mol Genet Metab 2009; 98:372-7. [PMID: 19699128 DOI: 10.1016/j.ymgme.2009.07.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 07/17/2009] [Accepted: 07/17/2009] [Indexed: 10/20/2022]
Abstract
Mitochondrial trifunctional protein (MTP) deficiency is a rare inherited metabolic disorder of mitochondrial fatty acid oxidation. We newly characterized three novel mutations in 2 Japanese patients with MTP deficiency, and investigated the clinical and molecular aspects of 5 Japanese patients including 3 previously reported cases. Herein, we describe the characterization of four missense mutations, R214C, H346R, R411K, and V422G, in the HADHB gene, which have been identified in Japanese patients, employing a newly developed, sensitive transient expression analysis. Co-transfection of wild-type HADHA and HADHB cDNAs in SV40-transfected fibroblasts from a MTP-deficient patient yielded sufficient enzyme activity to evaluate low-level residual enzyme activity, using two incubation temperatures of 30 degrees C and 37 degrees C. At 30 degrees C, residual enzyme activity was higher than that at 37 degrees C in V422G, R214C, and R411K. However, H346R, which was seen in the most severe case, showed no enzyme activity at both temperatures. Our results demonstrate that a defect of HADHB in MTP deficiency is rather common in Japanese patients, and the mutational spectrum is heterogeneous. The present findings showed that all missense mutations in this study were disease-causing. Although the number of patients is still limited, it is suggested that the phenotype is correlated with the genotype and a combination of two mutant alleles of the HADHB gene in MTP deficiency.
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Affiliation(s)
- Jamiyan Purevsuren
- Department of Pediatrics, Shimane University, Faculty of Medicine, Izumo, Japan
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18
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Jin J, Park J, Kim K, Kang Y, Park SG, Kim JH, Park KS, Jun H, Kim Y. Detection of differential proteomes of human beta-cells during islet-like differentiation using iTRAQ labeling. J Proteome Res 2009; 8:1393-403. [PMID: 19199707 DOI: 10.1021/pr800765t] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A human beta-cell line, RNAKT-15, was recently established from human pancreatic islets, whereby its differentiation into islet-like beta-cells (islet-like RNAKT-15) increased its expression of insulin 2-fold compared with RNAKT-15 cells. To characterize the differentiation of RNAKT-15 cells into islet-like RNAKT-15, microarray and quantitative proteomics were performed. Our analysis of differential proteomic and mRNA expression has resulted in a greater understanding of the molecular functions that are involved in beta-cell differentiation and insulin synthesis and release.
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Affiliation(s)
- Jonghwa Jin
- Departments of Biomedical Sciences and Internal Medicine, Genome Research Center for Diabetes and Endocrine Disease, Seoul National University College of Medicine, 28 Yongon-Dong, Seoul 110-799, Korea
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19
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Rector RS, Payne RM, Ibdah JA. Mitochondrial trifunctional protein defects: clinical implications and therapeutic approaches. Adv Drug Deliv Rev 2008; 60:1488-96. [PMID: 18652860 DOI: 10.1016/j.addr.2008.04.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Accepted: 04/21/2008] [Indexed: 02/09/2023]
Abstract
The mitochondrial trifunctional protein (MTP) is a heterotrimeric protein that consists of four alpha-subunits and four beta-subunits and catalyzes three of the four chain-shortening reactions in the mitochondrial beta-oxidation of long-chain fatty acids. Families with recessively inherited MTP defects display a spectrum of maternal and fetal phenotypes. Current management of patients with MTP defects include long-term dietary therapy of fasting avoidance, low-fat/high-carbohydrate diet with restriction of long-chain fatty acid intake and substitution with medium-chain fatty acids. These dietary approaches appear promising in the short-term, but the long-term outcome of patients treated with dietary intervention is largely unknown. Potential therapeutic approaches targeted at correcting the metabolic defect will be discussed. We will discuss the potential use of protein transduction domains that cross the mitochondrial membranes for the treatment of mitochondrial disorders. In addition, we discuss the phenotypes of MTP in a heterozygous state and potential ways to intervene to increase hepatic fatty acid oxidative capacity.
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20
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Purevsuren J, Fukao T, Hasegawa Y, Fukuda S, Kobayashi H, Yamaguchi S. Study of deep intronic sequence exonization in a Japanese neonate with a mitochondrial trifunctional protein deficiency. Mol Genet Metab 2008; 95:46-51. [PMID: 18693053 DOI: 10.1016/j.ymgme.2008.06.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 06/25/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
Abstract
Mitochondrial trifunctional protein (MTP) comprises heterooctamer alpha4beta4 and a deficiency in this protein causes a mitochondrial long-chain beta-oxidation defect. Here, we describe the molecular basis of an MTPbeta-subunit deficiency in a Japanese neonate. Mutation screening at the genomic level including all exons and exon-intron boundaries identified a novel c.1136A>G (H346R) mutation in exon 13 of the maternal allele, but none in the paternal allele. Analysis by RT-PCR identified paternal-specific 106- and 56-bp intronic insertions between exons 7 and 8, which introduced premature terminations. This intronic exonization was caused by a deep intronic mutation in intron 7 on the paternal allele that generates a cryptic splice donor site. This is the first report of a deep intronic mutation in MTP deficiency.
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Affiliation(s)
- Jamiyan Purevsuren
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 Enya, Izumo, Shimane 693-8501, Japan.
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21
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Characterization of mitochondrial trifunctional protein and its inactivation study for medicine development. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1742-9. [PMID: 18640292 DOI: 10.1016/j.bbapap.2008.06.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2008] [Revised: 06/11/2008] [Accepted: 06/23/2008] [Indexed: 11/21/2022]
Abstract
Mitochondrial trifunctional protein (MTP) catalyzes three consecutive step reactions in the beta-oxidation of long-chain fatty acids, and plays important roles in control and regulation of the beta-oxidation. We overexpressed in E. coli, and purified the MTP as a Mistic fusion protein, which was found to be an alpha(2)beta(2) protein complex and characterized with kinetic studies. Trimetazidine, used for treating chronic stable angina, has been proposed to be an inhibitor of the beta-subunit. We found that a catalytic cysteine residue C105 was labeled by trimetazidine through MS/MS analysis of a trimetazidine-labeled peptide fragment obtained from pepsin digested beta-subunit inactivated by trimetazidine. The MTP beta-subunit was then comparatively studied with monofunctional 3-ketoacyl-CoA thiolase through sequence alignment, site-directed mutagenesis, characterization of variant enzymes with kinetic studies, and homology modeling. The results indicate that the catalytic residues of the MTP beta-subunit are positioned in the active site similarly to those of monofunctional 3-ketoacyl-CoA thiolase.
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Abstract
Acute fatty liver of pregnancy (AFLP) is a serious maternal illness occurring in the third trimester of pregnancy with significant perinatal and maternal mortality. Till recently, it has been considered a mysterious illness. In this editorial, we review the recent advances in understanding the pathogenesis of AFLP and discuss the studies documenting a fetal-maternal interaction with a causative association between carrying a fetus with a defect in mitochondrial fatty acid oxidation and development of AFLP. Further, we discuss the impact of these recent advances on the offspring born to women who develop AFLP, such that screening for a genetic defect can be life saving to the newborn and would allow genetic counseling in subsequent pregnancies. The molecular basis and underlying mechanism for this unique fetal-maternal interaction causing maternal liver disease is discussed.
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Ibdah JA, Perlegas P, Zhao Y, Angdisen J, Borgerink H, Shadoan MK, Wagner JD, Matern D, Rinaldo P, Cline JM. Mice heterozygous for a defect in mitochondrial trifunctional protein develop hepatic steatosis and insulin resistance. Gastroenterology 2005; 128:1381-90. [PMID: 15887119 DOI: 10.1053/j.gastro.2005.02.001] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Little is known about the role of mitochondrial beta-oxidation in development of nonalcoholic fatty liver disease (NAFLD). Mitochondrial trifunctional protein (MTP) catalyzes long-chain fatty acid oxidation. Recently, we generated a mouse model for MTP deficiency and reported that homozygous (MTPa-/-) mice suffer neonatal death. In this study, we investigated effects of heterozygosity for the MTP defect on hepatic oxidative stress, insulin resistance, and development of NAFLD in mice. METHODS We evaluated liver histopathology, serum alanine aminotransferase (ALT), glucose, fatty acids, and insulin levels in MTPa+/- and MTPa+/+ littermates. Insulin resistance was evaluated using glucose tolerance test (GTT) and insulin tolerance test (ITT). Liver tissues were used to measure triglyceride and fatty acid content, activity of superoxide dismutases (SOD) and glutathione peroxidase (GPx), glutathione (GSH), and cytochrome P-450 2E1 expression. RESULTS Aging but not young MTPa+/- mice developed hepatic steatosis with elevated ALT, basal hyperinsulinemia, and increased insulin area under curve (AUC) on GTT compared with MTPa+/+ littermates. In response to insulin challenge, aging MTPa+/- mice had slower rate of glucose disappearance and increased glucose AUC. Significant hepatic steatosis and insulin resistance developed concomitantly in the MTPa+/- mice at 9-10 months of age. Aging MTPa+/- mice had higher antioxidant activity of total SOD and GPx, lower GSH, and increased expression of cytochrome P-450 2E1, consistent with increased hepatic oxidative stress. CONCLUSIONS Heterozygosity for beta-oxidation defects predisposes to NAFLD and insulin resistance in aging mice. Impairment of mitochondrial beta-oxidation may play an important role in pathogenesis of NAFLD.
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Affiliation(s)
- Jamal A Ibdah
- Division of Gastroenterology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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24
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Blish KR, Ibdah JA. Maternal heterozygosity for a mitochondrial trifunctional protein mutation as a cause for liver disease in pregnancy. Med Hypotheses 2005; 64:96-100. [PMID: 15533621 DOI: 10.1016/j.mehy.2004.06.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Accepted: 06/04/2004] [Indexed: 12/27/2022]
Abstract
Acute fatty liver of pregnancy (AFLP) and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome are serious complications of pregnancy associated with significant maternal and perinatal morbidity and mortality. In previous reports, we have documented an association between AFLP and fetal deficiency of long-chain 3-hydroxyacyl coenzyme A dehydrogenase (LCHAD) [N. Engl. J. Med. 340 (1999) 1723-1731; JAMA 288 (2002) 2163-2166]. LCHAD activity resides in the alpha-subunit of the mitochondrial trifunctional protein (MTP), a complex protein that catalyzes beta-oxidation of long chain fatty acids. In all reported cases, the fetus carried a common alpha-subunit MTP mutation (G1528C, E474Q) on one or both alleles. However, the association between fetal LCHAD deficiency and the maternal HELLP syndrome has been limited. Here, we report a case history of a 27-year-old black female who underwent Cesarean section for placenta previa and fetal distress at 36 weeks gestation. The newborn was a healthy male child. Post-delivery, the mother developed severe HELLP syndrome with complications resulting in death of the patient. We used single strand conformation variance and nucleotide sequence analyses to screen DNA isolated from the mother and the newborn for mutations in the MTP alpha-subunit. The mother was heterozygous for a novel mutation (C1072A, Q322K) in exon 11 of the LCHAD domain of the MTP, while the fetal genotype was completely normal. We hypothesize that, in some cases, maternal heterozygosity for an MTP mutation maybe sufficient to cause the development of maternal liver disease without carrying an affected fetus. Combination of the metabolic stress of pregnancy and other environmental stresses may overwhelm the heterozygous mother's capacity for effective metabolism of long chain fatty acids, leading to an accumulation of potentially toxic fatty acid metabolites in the maternal circulation with subsequent damage to the maternal liver.
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Affiliation(s)
- Kimberly R Blish
- Division of Gastroenterology, Department of Internal Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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25
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Tyni T, Paetau A, Strauss AW, Middleton B, Kivelä T. Mitochondrial fatty acid beta-oxidation in the human eye and brain: implications for the retinopathy of long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Pediatr Res 2004; 56:744-50. [PMID: 15347768 DOI: 10.1203/01.pdr.0000141967.52759.83] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The retinal pigment epithelium (RPE) and the choriocapillaris are affected early in the retinopathy associated with long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency. RPE in culture possesses the machinery needed for mitochondrial fatty acid beta-oxidation in vitro. To further elucidate pathogenesis of LCHAD retinopathy, we performed immunohistochemistry of the human eye and brain with antibodies to beta-oxidation enzymes. Human eye and brain sections were stained with antibodies to medium-chain (MCAD) and very long-chain acyl-CoA dehydrogenase (VLCAD), short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD), and mitochondrial trifunctional protein (MTP) harboring LCHAD. Antibodies to 2-methyl-3-hydroxybutyryl-CoA dehydrogenase (MHBD) and cytochrome c oxidase subunit I (COX I) were used as a reference. VLCAD, MTP, MCAD, SCHAD, MHBD, and COX I antibodies labeled most retinal layers and tissues of the human eye actively involved in oxidative metabolism (extraocular and intraocular muscle, the RPE, the corneal endothelium, and the ciliary epithelium). MTP and COX I antibodies labeled the inner segments of photoreceptors. The choriocapillaris was labeled only with SCHAD and MCAD antibodies. In the brain, the choroid plexus and nuclei of the brain stem were most intensely labeled with beta-oxidation antibodies, whereas COX I antibodies strongly labeled neurons in several regions of the brain. Mitochondrial fatty acid beta-oxidation likely plays a role in ocular energy production in vivo. The RPE rather than the choriocapillaris could be the critical affected cell layer in LCHAD retinopathy. Reduced energy generation in the choroid plexus may contribute to the cerebral edema observed in patients with beta-oxidation defects.
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Affiliation(s)
- Tiina Tyni
- Department of Pediatric Neurology, Hospital for Children and Adolescents, Helsinki University Central Hospital, 00029 HUS, Helsinki, Finland.
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Yamazaki H, Torigoe K, Numata O, Haniu H, Uchiyama A, Ogawa Y, Kaneko U, Imamura M, Hasegawa S. Mitochondrial trifunctional protein deficiency in a lethal neonate. Pediatr Int 2004; 46:178-80. [PMID: 15056246 DOI: 10.1046/j.1442-200x.2004.01861.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Hajime Yamazaki
- Department of Pediatrics, Nagaoka Red Cross Hospital, Nagaoka, Japan.
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Spiekerkoetter U, Khuchua Z, Yue Z, Bennett MJ, Strauss AW. General mitochondrial trifunctional protein (TFP) deficiency as a result of either alpha- or beta-subunit mutations exhibits similar phenotypes because mutations in either subunit alter TFP complex expression and subunit turnover. Pediatr Res 2004; 55:190-6. [PMID: 14630990 DOI: 10.1203/01.pdr.0000103931.80055.06] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The mitochondrial trifunctional protein (TFP) is a multienzyme complex of the beta-oxidation cycle. Human TFP is an octamer composed of four alpha-subunits harboring long-chain enoyl-CoA hydratase and long-chain L-3-hydroxyacyl-CoA dehydrogenase and four beta-subunits encoding long-chain 3-ketoacyl-CoA thiolase. Mutations in either subunit may result in general TFP deficiency with reduced activity of all three enzymes. We report five new patients with alpha-subunit mutations and compare general TFP deficiency caused by alpha-subunit mutations (n = 15) to that caused by beta-subunit mutations (n = 13) with regard to clinical features, enzyme activity, mutations, thiolase expression, and thiolase protein turnover. Among patients with alpha-subunit mutations, the same three heterogeneous phenotypes reported in patients with beta-subunit mutations were observed: a lethal form with predominating cardiomyopathy; an infancy-onset, hepatic presentation; and a milder, later-onset, neuromyopathic form. Maternal HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) occurred with an incidence of 15 to 20%, as in families with beta-subunit mutations. Enzyme assays in fibroblasts revealed an identical biochemical pattern in both groups. alpha-Subunit mutational analysis demonstrated molecular heterogeneity, with 53% (9 of 17) truncating mutations. In contrast, patients with beta-subunit mutations had predominantly missense mutations. Thiolase expression in fibroblasts was as markedly reduced in alpha-subunit patients as in the beta-subunit group with similarly increased thiolase degradation, presumably secondary to TFP complex instability. TFP deficiency as a result of either alpha- or beta-subunit mutations presents with similar, heterogeneous phenotypes. Both alpha- and beta-subunit mutations result in TFP complex instability, demonstrating that the mechanism of disease is the same in alpha- or beta-mutation-derived disease and explaining the biochemical and clinical similarities.
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Affiliation(s)
- Ute Spiekerkoetter
- Department of Pediatrics and Vanderbilt Children's Hospital, Nashville, TN 37232, USA.
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Emura I, Usuda H. Morphological investigation of two sibling autopsy cases of mitochondrial trifunctional protein deficiency. Pathol Int 2003; 53:775-9. [PMID: 14629302 DOI: 10.1046/j.1440-1827.2003.01558.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two sibling autopsy cases of type 2 mitochondrial trifunctional protein (MTP) deficiency are described. MTP is an enzyme complex involved in the mitochondrial beta-oxidation of fatty acids, which is the major pathway for energy production in heart and skeletal muscle. Both cases showed similar pathological findings. Numerous small foci of degeneration of muscle cells and cardiac myocytes were detected. Some of these cells had condensed or fragmented nuclei and most of them were positively stained using the deoxyuridine triphosphate nick-end labeling method. The lipid staining of both cases showed a small- to medium-sized fatty, vesicular morphology for liver cells, muscle cells, cardiac myocytes and proximal tubular cells of the kidney. Bone marrow was severely hypoplastic, and cortical thymocytes were markedly reduced in number. Neither case had hepatic fibrosis nor cirrhosis. The definitive diagnosis of type 2 MTP deficiency was made by verifying completely defective MTP-alpha and MTP-beta subunits in cultured skin fibroblasts of one of 2 patients. Our patients' signs indicate that there is a wider pathological spectrum of type 2 MTP deficiency, while very few autopsy cases of type 2 MTP deficiency have been confirmed. Pathologists should consider the possibility of type 2 MTP deficiency or other beta-oxidation defects in cases of sudden infant death, fatty infiltration of viscera or cardiomyopathy.
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Affiliation(s)
- Iwao Emura
- Department of Surgical Pathology, Nagaoka Red Cross Hospital, Nagaoka, Japan.
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29
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Matthews RP, Russo P, Berry GT, Piccoli DA, Rand EB. Biliary atresia associated with a fatty acid oxidation defect. J Pediatr Gastroenterol Nutr 2002; 35:624-8. [PMID: 12454576 DOI: 10.1097/00005176-200211000-00007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Randolph P Matthews
- Department of Pediatrics, Division of Gastroenterology and Nutrition and Fred and Suzanne Biesecker Liver Center, Philadelphia, Pennsylvania, USA
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30
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Tyni T, Johnson M, Eaton S, Pourfarzam M, Andrews R, Turnbull DM. Mitochondrial fatty acid beta-oxidation in the retinal pigment epithelium. Pediatr Res 2002; 52:595-600. [PMID: 12357056 DOI: 10.1203/00006450-200210000-00021] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pigmentary retinopathy is an important feature of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, a disorder of mitochondrial fatty acid beta-oxidation. Pathogenesis of this complication remains unknown. The retinal pigment epithelium (RPE) is affected early in this retinopathy. We wanted to determine whether there is evidence of mitochondrial fatty acid beta-oxidation in the RPE cells. Fatty acid oxidation was measured from cultured porcine RPE cells by incubating them with [U-13C]-hexadecanoic acid. Acylcarnitine esters were analyzed by tandem mass spectrometry. The activity of LCHAD and carnitine uptake capacity were measured from the cultured cells. Antibodies to the human mitochondrial trifunctional protein (MTP) containing LCHAD activity were used to analyze the expression of the MTP in the cultured RPE cell lysate and in human retinal sections by immunoblotting and immunohistochemistry. Fatty acid oxidation analysis showed normal chain shortening of hexadecanoic acid and production of acetylcarnitine in cultured RPE cells. Immunoblotting revealed expression of the MTP and enzyme assay showed the activity of LCHAD in the RPE cells. RPE cells were also capable of carnitine uptake. Positive labeling to the MTP antibodies was detected in the RPE, photoreceptors, and ganglion cells. The results give strong in vitro evidence for the presence of mitochondrial fatty acid beta-oxidation in RPE cells and the expression of the MTP in the RPE and other layers of the retina. Further studies are required to clarify whether this pathway acts also in vivo in the retina.
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Affiliation(s)
- Tiina Tyni
- Department of Neurology, University of Newcastle upon Tyne, UK.
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31
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Yang Z, Zhao Y, Bennett MJ, Strauss AW, Ibdah JA. Fetal genotypes and pregnancy outcomes in 35 families with mitochondrial trifunctional protein mutations. Am J Obstet Gynecol 2002; 187:715-20. [PMID: 12237653 DOI: 10.1067/mob.2002.125893] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the effects of fetal genotype on maternal and fetal outcomes in families with mitochondrial trifunctional protein mutations in the United States. Trifunctional protein has 3 enzymatic activities that include long-chain 3-hydroxyacyl-CoA dehydrogenase, which catalyzes long-chain fatty acid beta-oxidation. STUDY DESIGN We analyzed pregnancy history and offspring genotypes in 35 families with heterogeneous mutations. The fetal genotype was determined in utero in 11 pregnancies and after birth in 50 pregnancies. RESULTS Forty-nine percent of the women who carried affected fetuses had acute fatty liver of pregnancy. Another 11% of the women had the syndrome of hemolysis, elevated liver enzymes, and low platelets, or preeclampsia. All women who had the maternal illness carried fetuses with isolated long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Sixty-eight percent and 43% of the affected pregnancies also were associated with premature delivery and intrauterine growth retardation, respectively. No maternal or fetal complications were associated with heterozygous or wild-type fetal genotypes. CONCLUSION Fetal mitochondrial trifunctional protein defects should be considered a cause for maternal liver disease, preterm labor, and intrauterine growth retardation.
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Affiliation(s)
- Zi Yang
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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32
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Ibdah JA, Paul H, Zhao Y, Binford S, Salleng K, Cline M, Matern D, Bennett MJ, Rinaldo P, Strauss AW. Lack of mitochondrial trifunctional protein in mice causes neonatal hypoglycemia and sudden death. J Clin Invest 2001; 107:1403-9. [PMID: 11390422 PMCID: PMC209324 DOI: 10.1172/jci12590] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial trifunctional protein (MTP) is a hetero-octamer of four alpha and four beta subunits that catalyzes the final three steps of mitochondrial long chain fatty acid beta-oxidation. Human MTP deficiency causes Reye-like syndrome, cardiomyopathy, or sudden unexpected death. We used gene targeting to generate an MTP alpha subunit null allele and to produce mice that lack MTP alpha and beta subunits. The Mtpa(-/-) fetuses accumulate long chain fatty acid metabolites and have low birth weight compared with the Mtpa(+/-) and Mtpa(+/+) littermates. Mtpa(-/-) mice suffer neonatal hypoglycemia and sudden death 6-36 hours after birth. Analysis of the histopathological changes in the Mtpa(-/-) pups revealed rapid development of hepatic steatosis after birth and, later, significant necrosis and acute degeneration of the cardiac and diaphragmatic myocytes. This mouse model documents that intact mitochondrial long chain fatty acid oxidation is essential for fetal development and for survival after birth. Deficiency of MTP causes fetal growth retardation, neonatal hypoglycemia, and sudden death.
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Affiliation(s)
- J A Ibdah
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
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33
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Baldwin GS. Inhibition of the preferential binding of actin to the N-terminal hydratase domain of the 78-kDa gastrin-binding protein by non-steroidal anti-inflammatory drugs and gastrin receptor antagonists. Biochem Pharmacol 2001; 61:1129-36. [PMID: 11301046 DOI: 10.1016/s0006-2952(01)00563-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The 78 kDa gastrin-binding protein (GBP) is a likely target for the antiproliferative effects of gastrin receptor antagonists and non-steroidal anti-inflammatory drugs (NSAIDs) on colorectal carcinoma cells (Baldwin GS, Murphy VJ, Yang Z, and Hashimoto T. J Pharmacol Exp Ther 1998;286:1110-14). This study tested the hypotheses that the GBP bound actin, and that the interaction could be disrupted by gastrin receptor antagonists and NSAIDs. Binding of actin to the GBP was assessed by competition with (125)I-[Nle(15)]-gastrin(2,17) in a covalent cross-linking assay, and by comparison of (125)I-actin binding to the N- and C-terminal GBP domains, which had been expressed independently in E. coli as glutathione-S-transferase (GST) fusion proteins. The ability of gastrin receptor antagonists and NSAIDs to interfere with the actin-GBP interaction was measured by release of (125)I-actin from preformed complexes with the N- and C-terminal domain-GST fusion proteins. Actin purified from skeletal muscle or from gastric mucosal cytosol competed with (125)I-[Nle(15)]-gastrin(2,17) for binding to the GBP with IC(50) values of 2.6 +/- 0.7 microM, and 2.1 +/- 0.7 microM, respectively. The amount of (125)I-actin from either source bound to the N-terminal GBP domain was 8.2 times greater than the amount bound to the C-terminal domain. Binding of actin to both domains was inhibited by the gastrin receptor antagonists proglumide and benzotript, and by NSAIDs. We conclude that the GBP may associate with the cytoskeleton via an interaction between its N-terminal domain and actin, and that the association may be disrupted either by gastrin receptor antagonists or by NSAIDs.
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Affiliation(s)
- G S Baldwin
- Dept. of Surgery, University of Melbourne, Austin Campus, A&RMC, Studley Rd., Heidelberg, Victoria 3084, Australia.
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Ibdah JA, Zhao Y, Viola J, Gibson B, Bennett MJ, Strauss AW. Molecular prenatal diagnosis in families with fetal mitochondrial trifunctional protein mutations. J Pediatr 2001; 138:396-9. [PMID: 11241049 DOI: 10.1067/mpd.2001.111503] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To evaluate the feasibility of molecular prenatal diagnosis in families with mitochondrial trifunctional protein (TFP) mutations and prospectively study the effects of fetal genotype on pregnancy outcome. TFP catalyzes the last 3 steps in mitochondrial long-chain fatty acid oxidation. STUDY DESIGN We performed molecular prenatal diagnosis in 9 pregnancies, 8 in 6 families with isolated long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) deficiency and one in a family with complete TFP deficiency. Analyses were performed on chorionic villous samples in 7 pregnancies and on amniocytes in 2. RESULTS Molecular prenatal diagnosis successfully identified the fetal genotype in all 9 pregnancies. Two fetuses were affected, and both pregnancies were terminated by family decision. Two other fetuses had normal genotype and 5 others were heterozygotes. These 7 pregnancies were uncomplicated, and all the offspring are alive and apparently healthy. Genotypes of the aborted fetuses and neonates were confirmed by molecular analysis and enzymatic assays. CONCLUSIONS Molecular prenatal diagnosis is possible and valid in guiding management of pregnancies in families with known TFP defects. Women heterozygous for TFP alpha-subunit mutations who carry fetuses with wild-type or heterozygous genotypes have uncomplicated pregnancies.
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Affiliation(s)
- J A Ibdah
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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35
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Miyajima H, Ouchi Y, Sakamoto M, Takahashi Y, Kono S, Suzuki H. Increased anaerobic glycolysis in mitochondrial trifunctional protein-deficient brain. J Neurol Sci 2001; 184:197-201. [PMID: 11239956 DOI: 10.1016/s0022-510x(01)00445-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Deficiency of mitochondrial trifunctional protein (TP), beta-oxidation enzyme, is characterized by recurrent rhabdomyolysis in adult patients. Positron emission tomography was used to measure brain oxygen (CMRO(2)) and glucose (CMRGlc) metabolisms in an adult patient with TP deficiency who had a homozygous G1331A transition of the beta-subunit gene. The molar ratio of oxygen to glucose consumption showed diffuse reduction; CMRO(2) was markedly decreased, whereas CMRGlc increased. Oxidative metabolism may be impaired and anaerobic glycolysis stimulated in the brain of this patient with TP deficiency.
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Affiliation(s)
- H Miyajima
- The First Department of Medicine, Hamamatsu University School of Medicine, 3600 Handa-cho, Hamamatsu 431-3192, Japan.
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36
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Abstract
Acute fatty liver of pregnancy (AFLP) and the syndrome of hemolysis, elevated liver enzymes, and low platelets (the HELLP syndrome) are serious disorders of the third trimester with high maternal and perinatal morbidity and mortality. Over the past decade, several clinical observations have demonstrated an association between these maternal syndromes and a recessively inherited fatty acid oxidation disorder, long chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency. Many women who carried LCHAD-deficient fetuses developed maternal liver disease. Over the past few years, we and others have made significant progress in understanding the molecular basis for this fetal-maternal interaction. Here, we review the studies in literature that led to the establishment of this causative association with particular emphasis on the molecular analysis that delineated the molecular basis of this association. The likely mechanisms for the genotype-phenotype correlations in pediatric LCHAD deficiency and the fetal-maternal interaction are discussed. Finally, the potential implications of our current knowledge for families with pediatric LCHAD deficiency and for women who develop AFLP and HELLP syndrome are discussed.
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Affiliation(s)
- J A Ibdah
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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37
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Watanabe K, Fujii H, Takahashi T, Kodama M, Aizawa Y, Ohta Y, Ono T, Hasegawa G, Naito M, Nakajima T, Kamijo Y, Gonzalez FJ, Aoyama T. Constitutive regulation of cardiac fatty acid metabolism through peroxisome proliferator-activated receptor alpha associated with age-dependent cardiac toxicity. J Biol Chem 2000; 275:22293-9. [PMID: 10801788 DOI: 10.1074/jbc.m000248200] [Citation(s) in RCA: 251] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the nuclear receptor superfamily and mediates the biological effects of peroxisome proliferators. To determine the physiological role of PPARalpha in cardiac fatty acid metabolism, we examined the regulation of expression of cardiac fatty acid-metabolizing proteins using PPARalpha-null mice. The capacity for constitutive myocardial beta-oxidation of the medium and long chain fatty acids, octanoic acid and palmitic acid, was markedly reduced in the PPARalpha-null mice as compared with the wild-type mice, indicating that mitochondrial fatty acid catabolism is impaired in the absence of PPARalpha. In contrast, constitutive beta-oxidation of the very long chain fatty acid, lignoceric acid, did not differ between the mice, suggesting that the constitutive expression of enzymes involved in peroxisomal beta-oxidation is independent of PPARalpha(.) Indeed, PPARalpha-null mice had normal levels of the peroxisomal beta-oxidation enzymes except the D-type bifunctional protein. At least seven mitochondrial fatty acid-metabolizing enzymes were expressed at much lower levels in the PPARalpha-null mice, whereas other fatty acid-metabolizing enzymes were present at similar or slightly lower levels in the PPARalpha-null, as compared with wild-type mice. Additionally, lower constitutive mRNA expression levels of fatty acid transporters were found in the PPARalpha-null mice, suggesting a role for PPARalpha in fatty acid transport and catabolism. Indeed, in fatty acid metabolism experiments in vivo, myocardial uptake of iodophenyl 9-methylpentadecanoic acid and its conversion to 3-methylnonanoic acid were reduced in the PPARalpha-null mice. Interestingly, a decreased ATP concentration after exposure to stress, abnormal cristae of the mitochondria, abnormal caveolae, and fibrosis were observed only in the myocardium of the PPARalpha-null mice. These cardiac abnormalities appeared to proceed in an age-dependent manner. Taken together, the results presented here indicate that PPARalpha controls constitutive fatty acid oxidation, thus establishing a role for the receptor in cardiac fatty acid homeostasis. Furthermore, altered expression of fatty acid-metabolizing proteins seems to lead to myocardial damage and fibrosis, as inflammation and abnormal cell growth control can cause these conditions.
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Affiliation(s)
- K Watanabe
- Department of Clinical Pharmacology, Niigata College of Pharmacy, Niigata, Niigata 950-2081, Japan.
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38
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Abstract
Acute fatty liver of pregnancy (AFLP) and the childhood encephalopathy known as Reye's syndrome are both characterised by microvesicular steatosis. Mothers with AFLP are frequently heterozygous for a mutation which reduces the activity of the trifunctional protein (TP) of fatty-acid oxidation. Several lines of evidence suggest that blockade of fatty-acid oxidation may also be the underlying cause of Reye's syndrome, and epidemiological studies have identified aspirin taken during a viral illness as a contributing factor to the development of the disease. The hypotheses are presented:* that children with Reye's syndrome may also be heterozygous for TP mutation, and* that inhibition of the residual long-chain fatty-acid oxidation by NSAIDs including aspirin precipitates the similar symptoms observed in patients with Reye's syndrome and AFLP. Identification of NSAIDs as candidates for the unidentified factor which precipitates AFLP suggests that avoidance of NSAIDs during pregnancy may lead to a reduction in the incidence of this life-threatening disease.
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Affiliation(s)
- G S Baldwin
- University Department of Surgery, Austin Campus, A & RMC, Heidelberg, Victoria, Australia.
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39
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Yang SY, He XY. Molecular mechanisms of fatty acid beta-oxidation enzyme catalysis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:133-43. [PMID: 10709637 DOI: 10.1007/0-306-46818-2_15] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- S Y Yang
- Department of Pharmacology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, 10314, USA
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40
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Chevet E, Lemaître G, Cailleret K, Dahan S, Bergeron JJ, Katinka MD. Identification and characterization of an intracellular protein complex that binds fibroblast growth factor-2 in bovine brain. Biochem J 1999; 341 ( Pt 3):713-23. [PMID: 10417336 PMCID: PMC1220410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The fibroblast growth factor (FGF) family is composed of polypeptides with sequence identity which signal through transmembrane tyrosine kinase receptors. We report here the purification from bovine brain microsomes of an FGF-2-binding complex composed of three proteins of apparent molecular masses 150 kDa, 79 kDa and 46 kDa. Only the 150 kDa and 79 kDa proteins bound FGF-2 in cross-linking and ligand-blotting experiments. Binding of FGF-2 to p79 is enhanced in the presence of calcium. Peptide sequences allowed the identification of p150 and the cloning of the cDNAs encoding p79 and p46. The deduced amino acid sequence of p79 reveals high similarity to those of gastrin-binding protein and mitochondrial enoyl-CoA hydratase/hydroxyacyl-CoA dehydrogenase. p46 is similar to mitochondrial ketoacyl-CoA thiolase. Stable transfection of FR3T3 rat fibroblast cells with p79 cDNA analysed by electron microscopy following immunolabelling of ultra-thin cryosections revealed a localization of p79 in the secretory pathway, mainly in the endoplasmic reticulum and the Golgi region, where it is specifically associated with the molecular chaperone calnexin. In vivo a protein similar to the Golgi protein MG-160 forms a complex with FGF-2 and p79.
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Affiliation(s)
- E Chevet
- UER de Science, Université Paris XII, 61 avenue du Général De Gaulle, 94010 Créteil Cédex, France
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41
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Bennett MJ, Spotswood SD, Ross KF, Comfort S, Koonce R, Boriack RL, IJlst L, Wanders RJ. Fatal hepatic short-chain L-3-hydroxyacyl-coenzyme A dehydrogenase deficiency: clinical, biochemical, and pathological studies on three subjects with this recently identified disorder of mitochondrial beta-oxidation. Pediatr Dev Pathol 1999; 2:337-45. [PMID: 10347277 DOI: 10.1007/s100249900132] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This report describes the clinical, biochemical, and pathological findings in three infants with hepatic short-chain L-3-hydroxyacyl-coenzyme A dehydrogenase (SCHAD) deficiency, a recently recognized disorder of the mitochondrial oxidation of straight-chain fatty acids. Candidate subjects were identified from an ongoing study of infant deaths. SCHAD analysis was performed on previously frozen liver and skeletal muscle on subjects with a characteristic urine organic acid profile. Autopsy findings were correlated with the biochemical abnormalities. Enzyme analysis in liver revealed marked deficiency in SCHAD with residual activities of 3-11%. All subjects had normal activity in skeletal muscle. However, Western blot analysis of SCHAD revealed an identical truncated protein in both liver and muscle from one patient, suggesting that SCHAD is similar in liver and muscle and that the normal activity in muscle may be due to other enzymes with C4 activity. Autopsy findings revealed marked steatosis and a muscle pattern consistent with spinal muscular atrophy in one patient. Lipid storage was less pronounced in one patient and not detected in the third patient who had a well-documented history of recurrent hypoglycemia. This is the initial pathological characterization of this enzyme defect, and our observations suggest that SCHAD deficiency is a very severe disorder contributing to early infant death.
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Affiliation(s)
- M J Bennett
- Department of Pathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235, USA
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42
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Strauss AW, Bennett MJ, Rinaldo P, Sims HF, O'Brien LK, Zhao Y, Gibson B, Ibdah J. Inherited long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency and a fetal-maternal interaction cause maternal liver disease and other pregnancy complications. Semin Perinatol 1999; 23:100-12. [PMID: 10331463 DOI: 10.1016/s0146-0005(99)80044-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fetal-maternal interactions are critical determinants of maternal health during pregnancy and perinatal outcome. This review explores the causative relationship of a fetal disorder of mitochondrial fatty acid oxidation, long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, and the serious maternal liver diseases of pregnancy-preeclampsia, the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet counts), and acute fatty liver of pregnancy. Features of the metabolic adaptation necessitated during the fetal-neonatal transition; common phenotypes of pediatric fatty acid oxidation disorders, including neonatal hypoketotic, hypoglycemia and hepatic crisis; and clinical abnormalities of HELLP and acute fatty liver of pregnancy are presented. Evidence that a common mutation in the alpha-subunit (LCHAD) of trifunctional protein, E474Q, is always one of the mutant alleles in fetal isolated LCHAD deficiency associated with these disorders of pregnancy that cause high maternal, fetal, and newborn morbidity and mortality is reviewed. Recommendations for molecular testing for LCHAD deficiency in families with life-threatening maternal liver disease are given.
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Affiliation(s)
- A W Strauss
- Department of Pediatrics, Washington University School of Medicine, St Louis Children's Hospital, MO, USA
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43
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Abstract
The primary presentations of neuromuscular disease in the newborn period are hypotonia and weakness. Although metabolic myopathies are inherited disorders that present from birth and may present with subtle to marked neonatal hypotonia, a number of these defects are diagnosed classically in childhood, adolescence, or adulthood. Disorders of glycogen, lipid, or mitochondrial metabolism may cause three main clinical syndromes in muscle, namely, (1) progressive weakness with hypotonia (e.g., acid maltase, debrancher enzyme, and brancher enzyme deficiencies among the glycogenoses; carnitine uptake and carnitine acylcarnitine translocase defects among the fatty acid oxidation (FAO) defects; and cytochrome oxidase deficiency among the mitochondrial disorders) or (2) acute, recurrent, reversible muscle dysfunction with exercise intolerance and acute muscle breakdown or myoglobinuria (with or without cramps), e.g., phosphorylase, phosphofructokinase, and phosphoglycerate kinase among the glycogenoses and carnitine palmitoyltransferase II deficiency among the disorders of FAO or (3) both (e.g., long-chain or very long-chain acyl coenzyme A (CoA) dehydrogenase, short-chain L-3-hydroxyacyl-CoA dehydrogenase, and trifunctional protein deficiencies among the FAO defects). Episodes of exercise-induced myoglobinuria tend to present in later childhood or adolescence; however, myoglobinuria in the first year of life may occur in FAO disorders during catabolic crises precipitated by fasting or infection. The following is a survey of genetic disorders of glycogen and lipid metabolism resulting in myopathy, focusing primarily on those defects, to date, that have presented in the neonatal or early infancy period. Disorders of mitochondrial metabolism are discussed in another chapter.
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Affiliation(s)
- I Tein
- Department of Pediatrics, Hospital for Sick Children, University of Toronto, Ontario, Canada
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44
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Abstract
The enzymes involved in beta-oxidation spiral are schematically classified into two groups. The first group consists of palmitoyl-CoA oxidase, the L-bifunctional protein, which has been called as the bifunctional protein, and 3-ketoacyl-CoA thiolase. The second group consists of the newly confirmed enzymes, branched chain oxidase, the D-bifunctional protein, and sterol carrier protein x. The enzymes of the first group are inducible and act on the straight chain acyl-CoA substrates. But the enzymes of the second group are non-inducible and act on branched chain acyl-CoAs. Accordingly, bile acid formation and oxidation of pristanic acid derived from phytol are catalyzed by the enzymes of the second group but not by those of the first group. The functions of the peroxisomal system and methods of analysis of the enzymes are briefly summarized.
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Affiliation(s)
- T Hashimoto
- Department of Biochemistry, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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45
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Orii KE, Orii KO, Souri M, Orii T, Kondo N, Hashimoto T, Aoyama T. Genes for the human mitochondrial trifunctional protein alpha- and beta-subunits are divergently transcribed from a common promoter region. J Biol Chem 1999; 274:8077-84. [PMID: 10075708 DOI: 10.1074/jbc.274.12.8077] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human HADHA and HADHB genes encode the subunits of an enzyme complex, the trifunctional protein, involved in mitochondrial beta-oxidation of fatty acids. Both genes are located in the same region of chromosome 2p23. We isolated genomic clones, including 5' flanking regions, for HADHA and HADHB. Sequencing revealed that both of these genes are linked in a head-to-head arrangement on opposite strands and have in common a 350-bp 5' flanking region. The 5' flanking region has bidirectional promoter activity within this region; two cis elements proved critical for the activity. Transcription factor Sp1 functions as an activator for the bidirectional promoter by binding to both elements. Therefore, expression of trifunctional protein subunits are probably coordinately regulated by a common promoter and by Sp1.
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Affiliation(s)
- K E Orii
- Department of Pediatrics, Gifu University School of Medicine, Gifu 500-8076, Japan.
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Ibdah JA, Tein I, Dionisi-Vici C, Bennett MJ, IJlst L, Gibson B, Wanders RJ, Strauss AW. Mild trifunctional protein deficiency is associated with progressive neuropathy and myopathy and suggests a novel genotype-phenotype correlation. J Clin Invest 1998; 102:1193-9. [PMID: 9739053 PMCID: PMC509102 DOI: 10.1172/jci2091] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human mitochondrial trifunctional protein (TFP) is a heterooctamer of four alpha- and four beta-subunits that catalyzes three steps in the beta-oxidation spiral of long-chain fatty acids. TFP deficiency causes a Reye-like syndrome, cardiomyopathy, or sudden, unexpected death. We delineated the molecular basis for TFP deficiency in two patients with a unique phenotype characterized by chronic progressive polyneuropathy and myopathy without hepatic or cardiac involvement. Single-stranded conformation variance and nucleotide sequencing identified all patient mutations in exon 9 of the alpha-subunit. One patient is homozygous for the T845A mutation that substitutes aspartic acid for valine at residue 246. The second patient is a compound heterozygote for the T914A that substitutes asparagine for isoleucine at residue 269 and a C871T that creates a premature termination at residue 255. Allele-specific oligonucleotide hybridization studies revealed undetectable levels of the mRNA corresponding to the mutant allele carrying the termination codon. This study suggests a novel genotype-phenotype correlation in TFP deficiency; that is, mutations in exon 9 of the alpha-subunit, which encodes a linker domain between the NH2-terminal hydratase and the COOH-terminal 3-hydroxyacyl-CoA dehydrogenase, result in a unique neuromuscular phenotype.
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Affiliation(s)
- J A Ibdah
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Tyni T, Kivelä T, Lappi M, Summanen P, Nikoskelainen E, Pihko H. Ophthalmologic findings in long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency caused by the G1528C mutation: a new type of hereditary metabolic chorioretinopathy. Ophthalmology 1998; 105:810-24. [PMID: 9593380 DOI: 10.1016/s0161-6420(98)95019-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE The purpose of the study was to determine the nature and course of ophthalmic abnormalities in long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, a recently discovered disorder of mitochondrial fatty acid beta-oxidation. STUDY DESIGN The study design was a cohort (case series). PARTICIPANTS A retrospective review of the records of 15 children who had died during their first 2 years was performed. Also performed were a longitudinal reanalysis and cross-sectional clinical examination of four long-term survivors aged 5 to 31 years. MAIN OUTCOME MEASURES Visual acuity, refraction, visual fields, ophthalmoscopy, fluorescein angiography, biometry, corneal topography, electroretinography (ERG), visual-evoked potentials (VEPs), color vision, and dark adaptation were measured. RESULTS In seven children, ophthalmoscopic findings were within normal limits at 3 days to 13 months of age (median, 4.8 months). In 11 children, a granular retinal pigment epithelium (RPE), with or without pigment clumping in the macula, was seen at 4 months to 5 years of age (median, 9 months). Two long-term survivors, 16 and 31 years of age, eventually had circumscribed atrophy of the choroid, RPE, and retina, which coincided with a posterior staphyloma type 1. They had progressive axial myopia starting at 6 and 12 years of age and later paracentral scotomas leading to poor central vision. They suffered from early difficulty with mesopic vision, glare, and a severe generalized color vision deficiency that started as a tritanomaly. A third survivor was mildly myopic at 5 years of age. All four surviving patients had visually insignificant, flake-like supranuclear opacities in the lens. The ERG initially was normal but deteriorated during the first decade and later was unrecordable. The VEP responses remained fairly normal. Initially, angiography showed no blockade of the choroidal fluorescence because of the thin RPE. Filling of choroidal vessels was delayed, and the choriocapillaris and, later, larger choroidal vessels in the posterior pole became nonperfused. CONCLUSIONS In LCHAD deficiency, the fundus is normal at birth (stage 1). Soon, however, pigment dispersion occurs in the RPE (stage 2), followed by circumscribed chorioretinal atrophy, occlusion of choroidal vessels, and deterioration of central vision, often with relative sparing of the peripheral fundus (stage 3). Finally, posterior staphylomas and central scotomas may develop (stage 4). Developmental cataract, progressive myopia, and deterioration of visual fields and color vision are new findings in LCHAD deficiency. The chorioretinopathy and abnormal ERG precede the development of myopia and posterior staphyloma, which, in turn, coincide with the loss of macular vision. The authors postulate that the RPE or choriocapillaris is primarily affected. Awareness of the characteristic ocular features is important because of an opportunity for dietary treatment, genetic counseling, and prenatal diagnosis.
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Affiliation(s)
- T Tyni
- Department of Child Neurology, Children's Hospital, University of Helsinki, Finland
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Kamijo T, Indo Y, Souri M, Aoyama T, Hara T, Yamamoto S, Ushikubo S, Rinaldo P, Matsuda I, Komiyama A, Hashimoto T. Medium chain 3-ketoacyl-coenzyme A thiolase deficiency: a new disorder of mitochondrial fatty acid beta-oxidation. Pediatr Res 1997; 42:569-76. [PMID: 9357925 DOI: 10.1203/00006450-199711000-00002] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A Japanese male neonate died at 13 d of age after presenting at 2 d of age with vomiting, dehydration, metabolic acidosis, liver dysfunction, and terminal rhabdomyolysis with myoglobinuria. Multiple urine organic acid analyses consistently revealed a markedly elevated excretion of lactic acid, 3-hydroxybutyric acid, and saturated and unsaturated C6-C16 dicarboxylic acids, with predominant C12-C16 species. Oxidation of [1-14C]octanoic acid in cultured skin fibroblasts was significantly reduced (0.59 nmol/h/mg of protein; controls, 1.93 +/- 0.65), [1-14C]palmitic acid oxidation was 1.11 nmol/h/mg of protein (controls, 1.63 +/- 0.41). A systematic study of the catalytic activities of nine enzymes of the beta-oxidation cycle using the respective optimal substrate revealed a deficiency of a single enzyme not previously associated with a metabolic disorder, medium chain 3-ketoacyl-CoA thiolase (patient, 3.9 nmol/min/mg protein; controls (n = 6), 10.2 +/- 2.3). Immunoprecipitation with antibodies raised against medium chain 3-ketoacyl-CoA thiolase revealed a 60% decrease compared with controls.
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Affiliation(s)
- T Kamijo
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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IJlst L, Oostheim W, Ruiter JP, Wanders RJ. Molecular basis of long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency: identification of two new mutations. J Inherit Metab Dis 1997; 20:420-2. [PMID: 9266371 DOI: 10.1023/a:1005310903004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- L IJlst
- University of Amsterdam, Department of Clinical Chemistry, The Netherlands
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50
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He XY, Deng H, Yang SY. Importance of the gamma-carboxyl group of glutamate-462 of the large alpha-subunit for the catalytic function and the stability of the multienzyme complex of fatty acid oxidation from Escherichia coli. Biochemistry 1997; 36:261-8. [PMID: 8993342 DOI: 10.1021/bi961841e] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
His450 of the large alpha-subunit of the multienzyme complex of fatty acid oxidation from Escherichia coli was recently identified as an essential catalytic residue of L-3-hydroxyacyl-CoA dehydrogenase [He, X-Y., & Yang, S.-Y. (1996) Biochemistry 35, 9625-9630]. To explore the roles of acidic residues in the dehydrogenase catalysis, every conserved acidic residue in the dehydrogenase functional domain except for those in the NAD-binding motif was replaced with alanine. The resulting mutant complexes were overproduced and characterized. Their component enzymes other than the dehydrogenase were affected very slightly. Removal of the beta-carboxyl group of Asp524 and Asp542 caused only a 3- and 4-fold, respectively, decrease in the catalytic efficiency of the dehydrogenase, thereby showing that their involvement in the dehydrogenase catalysis was limited. In contrast, the alpha/Glu462-->Ala mutant complex showed a greater than 160-fold reduction in the kcat of the dehydrogenase in the forward direction without a significant change of the k(m) for the substrate. The catalytic properties of the alpha/Glu462-->Gln mutant complex were found to be similar to those of the alpha/Glu462-->Ala mutant complex except that the kcat of the dehydrogenase in the backward direction was about 4-fold lower and the Km for the substrate of the thiolase was 6-fold higher. It is concluded that the negative charge of the gamma-carboxyl group of Glu462, but not its ability to form a hydrogen bond, is critical for its interaction with His450, thereby assisting in the catalysis of the dehydrogenase. The pKa of His450 in the E.NADH binary complex was virtually unchanged by the replacement of Glu462 with Ala or Gln. It seems that the binding of substrate is necessary for forming a strong interaction between His450 and Glu462 with the result that the electroneutrality in the active site is maintained and the activation energy of the reaction is lowered. Additionally, the negative charge of Glu462 increases the thermostability of the multienzyme complex.
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Affiliation(s)
- X Y He
- Department of Pharmacology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314, USA
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