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Diaz-Vegas A, Cooke KC, Cutler HB, Yau B, Masson SWC, Harney D, Fuller OK, Potter M, Madsen S, Craw NR, Zhang Y, Moreno CL, Kebede MA, Neely GG, Stöckli J, Burchfield JG, James DE. Deletion of miPEP in adipocytes protects against obesity and insulin resistance by boosting muscle metabolism. Mol Metab 2024; 86:101983. [PMID: 38960128 PMCID: PMC11292358 DOI: 10.1016/j.molmet.2024.101983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/05/2024] Open
Abstract
Mitochondria facilitate thousands of biochemical reactions, covering a broad spectrum of anabolic and catabolic processes. Here we demonstrate that the adipocyte mitochondrial proteome is markedly altered across multiple models of insulin resistance and reveal a consistent decrease in the level of the mitochondrial processing peptidase miPEP. OBJECTIVE To determine the role of miPEP in insulin resistance. METHODS To experimentally test this observation, we generated adipocyte-specific miPEP knockout mice to interrogate its role in the aetiology of insulin resistance. RESULTS We observed a strong phenotype characterised by enhanced insulin sensitivity and reduced adiposity, despite normal food intake and physical activity. Strikingly, these phenotypes vanished when mice were housed at thermoneutrality, suggesting that metabolic protection conferred by miPEP deletion hinges upon a thermoregulatory process. Tissue specific analysis of miPEP deficient mice revealed an increment in muscle metabolism, and upregulation of the protein FBP2 that is involved in ATP hydrolysis in the gluconeogenic pathway. CONCLUSION These findings suggest that miPEP deletion initiates a compensatory increase in skeletal muscle metabolism acting as a protective mechanism against diet-induced obesity and insulin resistance.
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Affiliation(s)
- Alexis Diaz-Vegas
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia.
| | - Kristen C Cooke
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Harry B Cutler
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Belinda Yau
- School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Stewart W C Masson
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Dylan Harney
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Oliver K Fuller
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Meg Potter
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Søren Madsen
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Niamh R Craw
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Yiju Zhang
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Cesar L Moreno
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Melkam A Kebede
- School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - G Gregory Neely
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - Jacqueline Stöckli
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - James G Burchfield
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
| | - David E James
- School of Life and Environmental Sciences, University of Sydney, Camperdown, New South Wales, Australia; Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia; School of Medical Sciences, University of Sydney, Camperdown, New South Wales, Australia.
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Wang L, Lu P, Yin J, Xu K, Xiang D, Zhang Z, Zhang H, Zheng B, Zhou W, Wang C, Yang S. Case report: Rare novel MIPEP compound heterozygous variants presenting with hypertrophic cardiomyopathy, severe lactic acidosis and hypotonia in a Chinese infant. Front Cardiovasc Med 2023; 9:1095882. [PMID: 36727025 PMCID: PMC9884671 DOI: 10.3389/fcvm.2022.1095882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 12/29/2022] [Indexed: 01/18/2023] Open
Abstract
Background Mitochondrial intermediate peptidase, encoded by the MIPEP gene, is involved in the processing of precursor mitochondrial proteins related to oxidative phosphorylation. Only a few studies have shown that mutations in MIPEP can cause combined oxidative phosphorylation deficiency-31 (COXPD31), an autosomal recessive multisystem disorder associated with mitochondrial dysfunction. We report herein a rare case of an 8-month-old boy in China with hypertrophic cardiomyopathy (HCM), severe lactic acidosis, and hypotonia caused by novel MIPEP compound heterozygous variants. Methods Trio-whole-exome sequencing and copy number variation sequencing were performed to identify mutated genetic loci. Sanger sequencing and quantitative real-time PCR were used to validate the candidate single nucleotide variants and copy number variants, respectively. Results The proband was an 8-month-old boy with HCM, severe lactic acidosis, and hypotonia who died 2 months after his first admission. Two novel compound heterozygous variants, c.1081T > A (p. Tyr361Asn) and a whole deletion (Ex1-19 del), were found in the MIPEP gene, which were inherited from his healthy parents respectively. Additionally, his mitochondria DNA copy number was significantly reduced. Conclusion We are the first to report a patient with rare MIPEP variants in China. Our findings expand the mutation spectrum of MIPEP, and provide insights into the genotype-phenotype relationship in COXPD31.
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Affiliation(s)
- Ling Wang
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Pengtao Lu
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Jie Yin
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Kangkang Xu
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Dandan Xiang
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Zhongman Zhang
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Han Zhang
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Zhou
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Shiwei Yang
- Department of Cardiology, Children’s Hospital of Nanjing Medical University, Nanjing, China,*Correspondence: Shiwei Yang,
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Phenotype-Genotype Analysis Based on Molecular Classification in 135 Children With Mitochondrial Disease. Pediatr Neurol 2022; 132:11-18. [PMID: 35598585 DOI: 10.1016/j.pediatrneurol.2022.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/29/2022] [Accepted: 04/25/2022] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Over the past decades, mitochondrial disease classification has been mainly based on molecular defects. We aim to analyze phenotype-genotype correlation of mitochondrial disorders according to molecular classification. METHODS In this cohort study, we identified 135 individuals diagnosed with mitochondrial disorders, and all patients were divided into four subgroups based on molecular functions: the Respiratory Chain group (including subunits and assembly proteins in the respiratory chain), the Protein Synthesis group (including mitochondrial RNA metabolism, mitochondrial translation), the mitcohindrial DNA (mtDNA) Replication group, and the Others group (including cofactors, homeostasis, substrates, and inhibitors). RESULTS We found that in China, patients with the mtDNA variant constituted a large percentage of mitochondrial disease and were associated with a male preponderance in the Respiratory Chain group, whereas those in the Protein Synthesis group showed a relatively later onset and higher serum lactate level. In contrast, patients with nuclear DNA variants were younger at onset, with no specific lactate or cranial imaging features, especially in the Others group, which contained several mitochondrial diseases with corresponding treatment. CONCLUSION The mtDNA was recommended to detect first in patients with typical lactate and cranial imaging features. A broader consideration and detection are necessary for a better prognosis in an atypical patient.
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Kunová N, Havalová H, Ondrovičová G, Stojkovičová B, Bauer JA, Bauerová-Hlinková V, Pevala V, Kutejová E. Mitochondrial Processing Peptidases-Structure, Function and the Role in Human Diseases. Int J Mol Sci 2022; 23:1297. [PMID: 35163221 PMCID: PMC8835746 DOI: 10.3390/ijms23031297] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial proteins are encoded by both nuclear and mitochondrial DNA. While some of the essential subunits of the oxidative phosphorylation (OXPHOS) complexes responsible for cellular ATP production are synthesized directly in the mitochondria, most mitochondrial proteins are first translated in the cytosol and then imported into the organelle using a sophisticated transport system. These proteins are directed mainly by targeting presequences at their N-termini. These presequences need to be cleaved to allow the proper folding and assembly of the pre-proteins into functional protein complexes. In the mitochondria, the presequences are removed by several processing peptidases, including the mitochondrial processing peptidase (MPP), the inner membrane processing peptidase (IMP), the inter-membrane processing peptidase (MIP), and the mitochondrial rhomboid protease (Pcp1/PARL). Their proper functioning is essential for mitochondrial homeostasis as the disruption of any of them is lethal in yeast and severely impacts the lifespan and survival in humans. In this review, we focus on characterizing the structure, function, and substrate specificities of mitochondrial processing peptidases, as well as the connection of their malfunctions to severe human diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Eva Kutejová
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (H.H.); (G.O.); (B.S.); (J.A.B.); (V.B.-H.); (V.P.)
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Heidorn-Czarna M, Maziak A, Janska H. Protein Processing in Plant Mitochondria Compared to Yeast and Mammals. FRONTIERS IN PLANT SCIENCE 2022; 13:824080. [PMID: 35185991 PMCID: PMC8847149 DOI: 10.3389/fpls.2022.824080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/12/2022] [Indexed: 05/02/2023]
Abstract
Limited proteolysis, called protein processing, is an essential post-translational mechanism that controls protein localization, activity, and in consequence, function. This process is prevalent for mitochondrial proteins, mainly synthesized as precursor proteins with N-terminal sequences (presequences) that act as targeting signals and are removed upon import into the organelle. Mitochondria have a distinct and highly conserved proteolytic system that includes proteases with sole function in presequence processing and proteases, which show diverse mitochondrial functions with limited proteolysis as an additional one. In virtually all mitochondria, the primary processing of N-terminal signals is catalyzed by the well-characterized mitochondrial processing peptidase (MPP). Subsequently, a second proteolytic cleavage occurs, leading to more stabilized residues at the newly formed N-terminus. Lately, mitochondrial proteases, intermediate cleavage peptidase 55 (ICP55) and octapeptidyl protease 1 (OCT1), involved in proteolytic cleavage after MPP and their substrates have been described in the plant, yeast, and mammalian mitochondria. Mitochondrial proteins can also be processed by removing a peptide from their N- or C-terminus as a maturation step during insertion into the membrane or as a regulatory mechanism in maintaining their function. This type of limited proteolysis is characteristic for processing proteases, such as IMP and rhomboid proteases, or the general mitochondrial quality control proteases ATP23, m-AAA, i-AAA, and OMA1. Identification of processing protease substrates and defining their consensus cleavage motifs is now possible with the help of large-scale quantitative mass spectrometry-based N-terminomics, such as combined fractional diagonal chromatography (COFRADIC), charge-based fractional diagonal chromatography (ChaFRADIC), or terminal amine isotopic labeling of substrates (TAILS). This review summarizes the current knowledge on the characterization of mitochondrial processing peptidases and selected N-terminomics techniques used to uncover protease substrates in the plant, yeast, and mammalian mitochondria.
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