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Messina M, Vaz FM, Rahman S. Mitochondrial membrane synthesis, remodelling and cellular trafficking. J Inherit Metab Dis 2024. [PMID: 38872485 DOI: 10.1002/jimd.12766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/14/2024] [Accepted: 05/21/2024] [Indexed: 06/15/2024]
Abstract
Mitochondria are dynamic cellular organelles with complex roles in metabolism and signalling. Primary mitochondrial disorders are a group of approximately 400 monogenic disorders arising from pathogenic genetic variants impacting mitochondrial structure, ultrastructure and/or function. Amongst these disorders, defects of complex lipid biosynthesis, especially of the unique mitochondrial membrane lipid cardiolipin, and membrane biology are an emerging group characterised by clinical heterogeneity, but with recurrent features including cardiomyopathy, encephalopathy, neurodegeneration, neuropathy and 3-methylglutaconic aciduria. This review discusses lipid synthesis in the mitochondrial membrane, the mitochondrial contact site and cristae organising system (MICOS), mitochondrial dynamics and trafficking, and the disorders associated with defects of each of these processes. We highlight overlapping functions of proteins involved in lipid biosynthesis and protein import into the mitochondria, pointing to an overarching coordination and synchronisation of mitochondrial functions. This review also focuses on membrane interactions between mitochondria and other organelles, namely the endoplasmic reticulum, peroxisomes, lysosomes and lipid droplets. We signpost disorders of these membrane interactions that may explain the observation of secondary mitochondrial dysfunction in heterogeneous pathological processes. Disruption of these organellar interactions ultimately impairs cellular homeostasis and organismal health, highlighting the central role of mitochondria in human health and disease.
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Affiliation(s)
- Martina Messina
- Mitochondrial Research Group, Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Frédéric M Vaz
- Department of Laboratory Medicine and Pediatrics, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Inborn Errors of Metabolism, Amsterdam, The Netherlands
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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2
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Sadeesh EM, Lahamge MS, Malik A, Ampadi AN. Differential Expression of Nuclear-Encoded Mitochondrial Protein Genes of ATP Synthase Across Different Tissues of Female Buffalo. Mol Biotechnol 2024:10.1007/s12033-024-01085-x. [PMID: 38305843 DOI: 10.1007/s12033-024-01085-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 01/22/2024] [Indexed: 02/03/2024]
Abstract
The physiological well-being of buffaloes, encompassing phenotypic traits, reproductive health, and productivity, depends on their energy status. Mitochondria, the architects of energy production, orchestrate a nuanced interplay between nuclear and mitochondrial domains. Oxidative phosphorylation complexes and associated proteins wield significant influence over metabolic functions, energy synthesis, and organelle dynamics, often linked to tissue-specific pathologies. The unexplored role of ATP synthase in buffalo tissues prompted a hypothesis: in-depth exploration of nuclear-derived mitochondrial genes, notably ATP synthase, reveals distinctive tissue-specific diversity. RNA extraction and sequencing of buffalo tissues (kidney, heart, brain, and ovary) enabled precise quantification of nuclear-derived mitochondrial protein gene expression. The analysis unveiled 24 ATP synthase transcript variants, each with unique tissue-specific patterns. Kidney, brain, and heart exhibited elevated gene expression compared to ovaries, with 10, 8, and 19 up-regulated genes, respectively. The kidney showed 3 and 12 down-regulated genes compared to the brain and heart. The heart-brain comparison highlighted ten highly expressed genes in ATP synthase functions. Gene ontology and pathway analyses revealed enriched functions linked to ATP synthesis and oxidative phosphorylation, offering a comprehensive understanding of energy production in buffalo tissues. This analysis enhances understanding of tissue-specific gene expression, emphasizing the influence of energy demands. Revealing intricate links between mitochondrial gene expression and tissue specialization in buffaloes, it provides nuanced insights into tissue-specific expression of nuclear-encoded mitochondrial protein genes, notably ATP synthase, advancing the comprehension of buffalo tissue biology.
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Affiliation(s)
- E M Sadeesh
- Laboratory of Mitochondrial Biology of Farm Animals, Animal Biochemistry Division, ICAR- National Dairy Research Institute, Karnal, Haryana, 132001, India.
| | - Madhuri S Lahamge
- Laboratory of Mitochondrial Biology of Farm Animals, Animal Biochemistry Division, ICAR- National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - Anuj Malik
- Laboratory of Mitochondrial Biology of Farm Animals, Animal Biochemistry Division, ICAR- National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - A N Ampadi
- Laboratory of Mitochondrial Biology of Farm Animals, Animal Biochemistry Division, ICAR- National Dairy Research Institute, Karnal, Haryana, 132001, India
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3
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Genetic Complementation of ATP Synthase Deficiency Due to Dysfunction of TMEM70 Assembly Factor in Rat. Biomedicines 2022; 10:biomedicines10020276. [PMID: 35203486 PMCID: PMC8869460 DOI: 10.3390/biomedicines10020276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/05/2022] [Accepted: 01/18/2022] [Indexed: 11/17/2022] Open
Abstract
Mutations of the TMEM70 gene disrupt the biogenesis of the ATP synthase and represent the most frequent cause of autosomal recessive encephalo-cardio-myopathy with neonatal onset. Patient tissues show isolated defects in the ATP synthase, leading to the impaired mitochondrial synthesis of ATP and insufficient energy provision. In the current study, we tested the efficiency of gene complementation by using a transgenic rescue approach in spontaneously hypertensive rats with the targeted Tmem70 gene (SHR-Tmem70ko/ko), which leads to embryonic lethality. We generated SHR-Tmem70ko/ko knockout rats expressing the Tmem70 wild-type transgene (SHR-Tmem70ko/ko,tg/tg) under the control of the EF-1α universal promoter. Transgenic rescue resulted in viable animals that showed the variable expression of the Tmem70 transgene across the range of tissues and only minor differences in terms of the growth parameters. The TMEM70 protein was restored to 16–49% of the controls in the liver and heart, which was sufficient for the full biochemical complementation of ATP synthase biogenesis as well as for mitochondrial energetic function in the liver. In the heart, we observed partial biochemical complementation, especially in SHR-Tmem70ko/ko,tg/0 hemizygotes. As a result, this led to a minor impairment in left ventricle function. Overall, the transgenic rescue of Tmem70 in SHR-Tmem70ko/ko knockout rats resulted in the efficient complementation of ATP synthase deficiency and thus in the successful genetic treatment of an otherwise fatal mitochondrial disorder.
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Lin Y, Huang J, Zhu Z, Zhang Z, Xian J, Yang Z, Qin T, Chen L, Huang J, Huang Y, Wu Q, Hu Z, Lin X, Xu G. Overlap phenotypes of the left ventricular noncompaction and hypertrophic cardiomyopathy with complex arrhythmias and heart failure induced by the novel truncated DSC2 mutation. Orphanet J Rare Dis 2021; 16:496. [PMID: 34819141 PMCID: PMC8611834 DOI: 10.1186/s13023-021-02112-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/06/2021] [Indexed: 12/18/2022] Open
Abstract
Background The left ventricular noncompaction cardiomyopathy (LVNC) is a rare subtype of cardiomyopathy associated with a high risk of heart failure (HF), thromboembolism, arrhythmia, and sudden cardiac death. Methods The proband with overlap phenotypes of LVNC and hypertrophic cardiomyopathy (HCM) complicates atrial fibrillation (AF), ventricular tachycardia (VT), and HF due to the diffuse myocardial lesion, which were diagnosed by electrocardiogram, echocardiogram and cardiac magnetic resonance imaging. Peripheral blood was collected from the proband and his relatives. DNA was extracted from the peripheral blood of proband for high-throughput target capture sequencing. The Sanger sequence verified the variants. The protein was extracted from the skin of the proband and healthy volunteer. The expression difference of desmocollin2 was detected by Western blot. Results The novel heterozygous truncated mutation (p.K47Rfs*2) of the DSC2 gene encoding an important component of desmosomes was detected by targeted capture sequencing. The western blots showed that the expressing level of functional desmocollin2 protein (~ 94kd) was lower in the proband than that in the healthy volunteer, indicating that DSC2 p.K47Rfs*2 obviously reduced the functional desmocollin2 protein expression in the proband. Conclusion The heterozygous DSC2 p.K47Rfs*2 remarkably and abnormally reduced the functional desmocollin2 expression, which may potentially induce the overlap phenotypes of LVNC and HCM, complicating AF, VT, and HF.
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Affiliation(s)
- Yubi Lin
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Jiana Huang
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China.,Reproductive Center, The Six Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510000, China
| | - Zhiling Zhu
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Zuoquan Zhang
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Jianzhong Xian
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Zhe Yang
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Tingfeng Qin
- Department of Physiology, The School of Medicine of Jinan University, Guangzhou, 510000, China
| | - Linxi Chen
- Department of Physiology, The School of Medicine of Jinan University, Guangzhou, 510000, China
| | - Jingmin Huang
- Department of Physiology, The School of Medicine of Jinan University, Guangzhou, 510000, China
| | - Yin Huang
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Qiaoyun Wu
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China
| | - Zhenyu Hu
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117593, Singapore
| | - Xiufang Lin
- The Center of Cardiovascular Diseases, The Department of Cardiology, Radiology and Ultrasonography, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, China.
| | - Geyang Xu
- Department of Physiology, The School of Medicine of Jinan University, Guangzhou, 510000, China.
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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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6
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Zanfardino P, Doccini S, Santorelli FM, Petruzzella V. Tackling Dysfunction of Mitochondrial Bioenergetics in the Brain. Int J Mol Sci 2021; 22:8325. [PMID: 34361091 PMCID: PMC8348117 DOI: 10.3390/ijms22158325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022] Open
Abstract
Oxidative phosphorylation (OxPhos) is the basic function of mitochondria, although the landscape of mitochondrial functions is continuously growing to include more aspects of cellular homeostasis. Thanks to the application of -omics technologies to the study of the OxPhos system, novel features emerge from the cataloging of novel proteins as mitochondrial thus adding details to the mitochondrial proteome and defining novel metabolic cellular interrelations, especially in the human brain. We focussed on the diversity of bioenergetics demand and different aspects of mitochondrial structure, functions, and dysfunction in the brain. Definition such as 'mitoexome', 'mitoproteome' and 'mitointeractome' have entered the field of 'mitochondrial medicine'. In this context, we reviewed several genetic defects that hamper the last step of aerobic metabolism, mostly involving the nervous tissue as one of the most prominent energy-dependent tissues and, as consequence, as a primary target of mitochondrial dysfunction. The dual genetic origin of the OxPhos complexes is one of the reasons for the complexity of the genotype-phenotype correlation when facing human diseases associated with mitochondrial defects. Such complexity clinically manifests with extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. Finally, we briefly discuss the future directions of the multi-omics study of human brain disorders.
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Affiliation(s)
- Paola Zanfardino
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
| | - Stefano Doccini
- IRCCS Fondazione Stella Maris, Calambrone, 56128 Pisa, Italy;
| | | | - Vittoria Petruzzella
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
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Imai-Okazaki A, Matsunaga A, Yatsuka Y, Nitta KR, Kishita Y, Sugiura A, Sugiyama Y, Fushimi T, Shimura M, Ichimoto K, Tajika M, Tominaga M, Ebihara T, Matsuhashi T, Tsuruoka T, Kohda M, Hirata T, Harashima H, Nojiri S, Takeda A, Nakaya A, Kogaki S, Sakata Y, Ohtake A, Murayama K, Okazaki Y. Long-term prognosis and genetic background of cardiomyopathy in 223 pediatric mitochondrial disease patients. Int J Cardiol 2021; 341:48-55. [PMID: 34298071 DOI: 10.1016/j.ijcard.2021.06.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Cardiomyopathy is a risk factor for poor prognosis in pediatric patients with mitochondrial disease. However, other risk factors including genetic factors related to poor prognosis in mitochondrial disease has yet to be fully elucidated. METHODS AND RESULTS Between January 2004 and September 2019, we enrolled 223 consecutive pediatric mitochondrial disease patients aged <18 years with a confirmed genetic diagnosis, including 114 with nuclear gene mutations, 89 patients with mitochondrial DNA (mtDNA) point mutations, 11 with mtDNA single large-scale deletions and 9 with chromosomal aberrations. Cardiomyopathy at baseline was observed in 46 patients (22%). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for all-cause mortality. Over a median follow-up of 36 months (12-77), there were 85 deaths (38%). The overall survival rate was significantly lower in patients with cardiomyopathy than in those without (p < 0.001, log-rank test). By multivariable analysis, left ventricular (LV) hypertrophy (HR = 4.6; 95% CI: 2.8-7.3), neonatal onset (HR = 2.9; 95% CI: 1.8-4.5) and chromosomal aberrations (HR = 2.9; 95% CI: 1.3-6.5) were independent predictors of all-cause mortality. Patients with LV hypertrophy with neonatal onset and/or chromosomal aberrations had higher mortality (100% in 21 patients) than those with LV hypertrophy alone (71% in 14 patients). CONCLUSION In pediatric patients with mitochondrial disease, cardiomyopathy was common (22%) and was associated with increased mortality. LV hypertrophy, neonatal onset and chromosomal aberrations were independent predictors of all-cause mortality. Prognosis is particularly unfavourable if LV hypertrophy is combined with neonatal onset and/or chromosomal aberrations.
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Affiliation(s)
- Atsuko Imai-Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Ayako Matsunaga
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yukiko Yatsuka
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Kazuhiro R Nitta
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yoshihito Kishita
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Ayumu Sugiura
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Yohei Sugiyama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Takuya Fushimi
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Masaru Shimura
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Keiko Ichimoto
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Makiko Tajika
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Minako Tominaga
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Tomohiro Ebihara
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | | | - Tomoko Tsuruoka
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Masakazu Kohda
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Tomoko Hirata
- Laboratory for Comprehensive Genomic Analysis, RIKEN Centre for Integrative Medical Sciences, Kanagawa, Japan
| | - Hiroko Harashima
- Department of Paediatrics & Clinical Genomics, Saitama Medical University, Saitama, Japan; Centre for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Shuko Nojiri
- Clinical Research and Trial Centre, Juntendo University, Japan
| | - Atsuhito Takeda
- Department of Paediatrics, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan
| | - Akihiro Nakaya
- Department of Genome Data Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Shigetoyo Kogaki
- Department of Paediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yasushi Sakata
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Akira Ohtake
- Department of Paediatrics & Clinical Genomics, Saitama Medical University, Saitama, Japan; Centre for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Centre, Graduate School of Medicine, Juntendo University, Tokyo, Japan; Laboratory for Comprehensive Genomic Analysis, RIKEN Centre for Integrative Medical Sciences, Kanagawa, Japan.
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Fernandez-Vizarra E, Zeviani M. Mitochondrial disorders of the OXPHOS system. FEBS Lett 2020; 595:1062-1106. [PMID: 33159691 DOI: 10.1002/1873-3468.13995] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/21/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial disorders are among the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase [also called complex V (cV)]. The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by cV to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here, we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.
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Affiliation(s)
- Erika Fernandez-Vizarra
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Padova, Italy.,Department of Neurosciences, University of Padova, Italy
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9
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Finsterer J, Stöllberger C. Left Ventricular Noncompaction Syndrome: Genetic Insights and Therapeutic Perspectives. Curr Cardiol Rep 2020; 22:84. [DOI: 10.1007/s11886-020-01339-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Changes in the expression of oxidative phosphorylation complexes in the aging intestinal mucosa. Exp Gerontol 2020; 135:110924. [PMID: 32173460 DOI: 10.1016/j.exger.2020.110924] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 03/02/2020] [Accepted: 03/11/2020] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Mitochondria produce cellular energy via oxidative phosphorylation (OXPHOS), mediated by respiratory chain complexes I to IV and ATP synthase (complex V). Mitochondrial respiratory complexes have been shown to decline with age in several tissues. As the intestinal epithelium is a tissue with a high energy demand, the aim of the present study was to establish whether the expression profile of OXPHOS subunits in the intestinal mucosa changes during the aging process. DESIGN Biopsies of intestinal mucosa with no evidence of endoscopic or histomorphologic abnormalities, taken from 55 patients (mean age 42 years, age range 4-82 years; 62% female), were divided into four age groups (4-19, 20-39, 40-59, ≥60 years). Sections from different intestinal segments (terminal ileum, ascending colon, and sigmoid colon/rectum) were stained immunohistochemically (IHC) for subunits of OXPHOS complexes I-V and the voltage-dependent anion-selective channel 1 protein (VDAC1, porin), a marker of mitochondrial mass. Scores for IHC staining were determined by multiplication of the staining intensity and the percentage of positive cells. In addition, the numbers of intestinal crypts staining positive, partly positive, and negative were assessed. RESULTS The average protein expression levels of OXPHOS subunits increased continuously from childhood onward, peaked in persons aged 20 to 59 years, and declined thereafter. This was seen for complexes II to V in the terminal ileum, complexes I to V in the ascending colon, and complexes I to IV in the sigmoid colon/rectum. Across all age groups, no effect of age on expression of the porin subunit VDAC1 was detected. The number of complex I- and IV-negative crypts in different intestinal segments increased with age. CONCLUSION The protein expression levels of OXPHOS complexes increases from childhood onward and declines in elderly individuals, while the numbers of crypts with partial or complete loss of expression of complexes I and IV increase continuously with age. These data suggest that the continued reductions in the levels of mitochondrial OXPHOS complexes in crypts might be compensated in adulthood, but that, ultimately, reduced expression levels occur in persons aged 60 years and older. These findings raise two important questions: first, can the process of aging could be delayed through (pharmacological) intervention of mitochondrial pathways, and second, pathophysiologically, are these findings associated with disorders of the intestinal mucosa, e.g. inflammation?
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