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Jones DE, Klacking E, Ryan RO. Inborn errors of metabolism associated with 3-methylglutaconic aciduria. Clin Chim Acta 2021; 522:96-104. [PMID: 34411555 PMCID: PMC8464523 DOI: 10.1016/j.cca.2021.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 11/22/2022]
Abstract
A growing number of inborn errors of metabolism (IEM) associated with compromised mitochondrial energy metabolism manifest an unusual phenotypic feature: 3-methylglutaconic (3MGC) aciduria. Two major categories of 3MGC aciduria, primary and secondary, have been described. In primary 3MGC aciduria, IEMs in 3MGC CoA hydratase (AUH) or HMG CoA lyase block leucine catabolism, resulting in a buildup of pathway intermediates, including 3MGC CoA. Subsequent thioester hydrolysis yields 3MGC acid, which is excreted in urine. In secondary 3MGC aciduria, no deficiencies in leucine catabolism enzymes exist and 3MGC CoA is formed de novo from acetyl CoA. In the "acetyl CoA diversion pathway", when IEMs directly, or indirectly, interfere with TCA cycle activity, acetyl CoA accumulates in the matrix space. This leads to condensation of two acetyl CoA to form acetoacetyl CoA, followed by another condensation between acetyl CoA and acetoacetyl CoA to form 3-hydroxy, 3-methylglutaryl (HMG) CoA. Once formed, HMG CoA serves as a substrate for AUH, producing trans-3MGC CoA. Non enzymatic isomerization of trans-3MGC CoA to cis-3MGC CoA precedes intramolecular cyclization to cis-3MGC anhydride plus CoA. Subsequent hydrolysis of cis-3MGC anhydride gives rise to cis-3MGC acid, which is excreted in urine. In reviewing 20 discrete IEMs that manifest secondary 3MGC aciduria, evidence supporting the acetyl CoA diversion pathway was obtained. This biochemical pathway serves as an "overflow valve" in muscle / brain tissue to redirect acetyl CoA to 3MGC CoA when entry to the TCA cycle is impeded.
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Affiliation(s)
- Dylan E Jones
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Emma Klacking
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States.
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Hopkins AL, Nelson TAS, Guschina IA, Parsons LC, Lewis CL, Brown RC, Christian HC, Davies JS, Wells T. Unacylated ghrelin promotes adipogenesis in rodent bone marrow via ghrelin O-acyl transferase and GHS-R 1a activity: evidence for target cell-induced acylation. Sci Rep 2017; 7:45541. [PMID: 28361877 PMCID: PMC5374529 DOI: 10.1038/srep45541] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/21/2017] [Indexed: 11/09/2022] Open
Abstract
Despite being unable to activate the cognate ghrelin receptor (GHS-R), unacylated ghrelin (UAG) possesses a unique activity spectrum that includes promoting bone marrow adipogenesis. Since a receptor mediating this action has not been identified, we re-appraised the potential interaction of UAG with GHS-R in the regulation of bone marrow adiposity. Surprisingly, the adipogenic effects of intra-bone marrow (ibm)-infused acylated ghrelin (AG) and UAG were abolished in male GHS-R-null mice. Gas chromatography showed that isolated tibial marrow adipocytes contain the medium-chain fatty acids utilised in the acylation of UAG, including octanoic acid. Additionally, immunohistochemistry and immunogold electron microscopy revealed that tibial marrow adipocytes show prominent expression of the UAG-activating enzyme ghrelin O-acyl transferase (GOAT), which is located in the membranes of lipid trafficking vesicles and in the plasma membrane. Finally, the adipogenic effect of ibm-infused UAG was completely abolished in GOAT-KO mice. Thus, the adipogenic action of exogenous UAG in tibial marrow is dependent upon acylation by GOAT and activation of GHS-R. This suggests that UAG is subject to target cell-mediated activation – a novel mechanism for manipulating hormone activity.
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Affiliation(s)
- Anna L Hopkins
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Timothy A S Nelson
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Irina A Guschina
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Lydia C Parsons
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Charlotte L Lewis
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Richard C Brown
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Helen C Christian
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, OX1 3QX, UK
| | - Jeffrey S Davies
- Institute of Life Science, School of Medicine, Swansea University, Swansea, SA2 8PP, UK
| | - Timothy Wells
- Neuroscience &Mental Health Research Institute, and School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
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Bourne SC, Townsend KN, Shyr C, Matthews A, Lear SA, Attariwala R, Lehman A, Wasserman WW, van Karnebeek C, Sinclair G, Vallance H, Gibson WT. Optic atrophy, cataracts, lipodystrophy/lipoatrophy, and peripheral neuropathy caused by a de novo OPA3 mutation. Cold Spring Harb Mol Case Stud 2017; 3:a001156. [PMID: 28050599 PMCID: PMC5171695 DOI: 10.1101/mcs.a001156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022] Open
Abstract
We describe a woman who presented with cataracts, optic atrophy, lipodystrophy/lipoatrophy, and peripheral neuropathy. Exome sequencing identified a c.235C > G p.(Leu79Val) variant in the optic atrophy 3 (OPA3) gene that was confirmed to be de novo. This report expands the severity of the phenotypic spectrum of autosomal dominant OPA3 mutations.
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Affiliation(s)
- Stephanie C Bourne
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Katelin N Townsend
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia V5Z 4H4, Canada
| | - Casper Shyr
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia V5Z 4H4, Canada
| | - Allison Matthews
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia V5Z 4H4, Canada
| | - Scott A Lear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia V5A 1S6, Canada
| | - Raj Attariwala
- AIM Medical Imaging, Vancouver, British Columbia V6H 1C9, Canada
| | - Anna Lehman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Wyeth W Wasserman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia V5Z 4H4, Canada
| | - Clara van Karnebeek
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia V5Z 4H4, Canada
| | - Graham Sinclair
- Department of Pathology, British Columbia Children's Hospital, Vancouver, British Columbia V6H 3N1, Canada
| | - Hilary Vallance
- Department of Pathology, British Columbia Children's Hospital, Vancouver, British Columbia V6H 3N1, Canada
| | - William T Gibson
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Child and Family Research Institute, British Columbia Children's Hospital, Vancouver, British Columbia V5Z 4H4, Canada
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