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Arnold BH, Sanislav O, Fisher PR, Annesley SJ. Plate-Based Assays for the Characterization of Mitochondrial and Cellular Phenotypes. Methods Mol Biol 2024; 2746:1-20. [PMID: 38070076 DOI: 10.1007/978-1-0716-3585-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
The mitochondria are essential to eukaryotic life, acting as key drivers of energy generation while also being involved in the regulation of many cellular processes including apoptosis, cell proliferation, calcium homeostasis, and metabolism. Mitochondrial diseases which disrupt these processes lead to a diverse range of pathologies and lack consistency in symptom presentation. In disease, mitochondrial activity and energy homeostasis can be adapted to cellular requirements, and studies using Dictyostelium and human lymphoblastoid cell lines have shown that such changes can be facilitated by the key cellular and energy regulators, TORC1 and AMPK. Fluorescence-based assays are increasingly utilized to measure mitochondrial and cell signalling function in mitochondrial disease research. Here, we describe a streamlined method for the simultaneous measurement of mitochondrial mass, membrane potential, and reactive oxygen species production using MitoTracker Green™ FM, MitoTracker Red™ CMXRos, and DCFH-DA probes. This protocol has been adapted for both Dictyostelium and human lymphoblastoid cell lines. We also describe a method for assessing TORC1 and AMPK activity simultaneously in lymphoblastoid cells. These techniques allow for the characterization of mitochondrial defects in a rapid and easy to implement manner.
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Affiliation(s)
- Benjamin Henry Arnold
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
| | - Oana Sanislav
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
| | - Paul Robert Fisher
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia
| | - Sarah Jane Annesley
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, VIC, Australia.
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2
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Fan HH, Fang SB, Chang YC, Huang ST, Huang CH, Chang PR, Chang WC, Yang LTL, Lin PC, Cheng HY. Effects of colonization-associated gene yqiC on global transcriptome, cellular respiration, and oxidative stress in Salmonella Typhimurium. J Biomed Sci 2022; 29:102. [PMID: 36457101 PMCID: PMC9714038 DOI: 10.1186/s12929-022-00885-0] [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: 09/22/2022] [Accepted: 11/20/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND yqiC is required for colonizing the Salmonella enterica serovar Typhimurium (S. Typhimurium) in human cells; however, how yqiC regulates nontyphoidal Salmonella (NTS) genes to influence bacteria-host interactions remains unclear. METHODS The global transcriptomes of S. Typhimurium yqiC-deleted mutant (ΔyqiC) and its wild-type strain SL1344 after 2 h of in vitro infection with Caco-2 cells were obtained through RNA sequencing to conduct comparisons and identify major yqiC-regulated genes, particularly those involved in Salmonella pathogenicity islands (SPIs), ubiquinone and menaquinone biosynthesis, electron transportation chains (ETCs), and carbohydrate/energy metabolism. A Seahorse XFp Analyzer and assays of NADH/NAD+ and H2O2 were used to compare oxygen consumption and extracellular acidification, glycolysis parameters, adenosine triphosphate (ATP) generation, NADH/NAD+ ratios, and H2O2 production between ΔyqiC and SL1344. RESULTS After S. Typhimurium interacts with Caco-2 cells, yqiC represses gene upregulation in aspartate carbamoyl transferase, type 1 fimbriae, and iron-sulfur assembly, and it is required for expressing ilvB operon, flagellin, tdcABCD, and dmsAB. Furthermore, yqiC is required for expressing mainly SPI-1 genes and specific SPI-4, SPI-5, and SPI-6 genes; however, it diversely regulates SPI-2 and SPI-3 gene expression. yqiC significantly contributes to menD expression in menaquinone biosynthesis. A Kyoto Encyclopedia of Genes and Genomes analysis revealed the extensive association of yqiC with carbohydrate and energy metabolism. yqiC contributes to ATP generation, and the analyzer results demonstrate that yqiC is required for maintaining cellular respiration and metabolic potential under energy stress and for achieving glycolysis, glycolytic capacity, and glycolytic reserve. yqiC is also required for expressing ndh, cydA, nuoE, and sdhB but suppresses cyoC upregulation in the ETC of aerobically and anaerobically grown S. Typhimurium; priming with Caco-2 cells caused a reversed regulation of yiqC toward upregulation in these ETC complex genes. Furthermore, yqiC is required for maintaining NADH/NAD+ redox status and H2O2 production. CONCLUSIONS Specific unreported genes that were considerably regulated by the colonization-associated gene yqiC in NTS were identified, and the key role and tentative mechanisms of yqiC in the extensive modulation of virulence factors, SPIs, ubiquinone and menaquinone biosynthesis, ETCs, glycolysis, and oxidative stress were discovered.
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Affiliation(s)
- Hung-Hao Fan
- grid.412955.e0000 0004 0419 7197Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhong Jheng Road, Jhong Ho, New Taipei City, 23561 Taiwan ,grid.412896.00000 0000 9337 0481Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan ,grid.412955.e0000 0004 0419 7197Department of Emergency Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Shiuh-Bin Fang
- grid.412955.e0000 0004 0419 7197Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhong Jheng Road, Jhong Ho, New Taipei City, 23561 Taiwan ,grid.412896.00000 0000 9337 0481Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan ,grid.412896.00000 0000 9337 0481Master Program for Clinical Genomics and Proteomics, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Yu-Chu Chang
- grid.412896.00000 0000 9337 0481Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sheng-Tung Huang
- grid.412087.80000 0001 0001 3889Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Chih-Hung Huang
- grid.412087.80000 0001 0001 3889Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Pei-Ru Chang
- grid.412955.e0000 0004 0419 7197Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhong Jheng Road, Jhong Ho, New Taipei City, 23561 Taiwan ,grid.412896.00000 0000 9337 0481Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wei-Chiao Chang
- grid.412896.00000 0000 9337 0481Master Program for Clinical Genomics and Proteomics, College of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Lauderdale Tsai-Ling Yang
- grid.59784.370000000406229172National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Pei-Chun Lin
- grid.412955.e0000 0004 0419 7197Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhong Jheng Road, Jhong Ho, New Taipei City, 23561 Taiwan
| | - Hung-Yen Cheng
- grid.412955.e0000 0004 0419 7197Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, No. 291, Jhong Jheng Road, Jhong Ho, New Taipei City, 23561 Taiwan
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Divakaruni AS, Jastroch M. A practical guide for the analysis, standardization and interpretation of oxygen consumption measurements. Nat Metab 2022; 4:978-994. [PMID: 35971004 PMCID: PMC9618452 DOI: 10.1038/s42255-022-00619-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 06/17/2022] [Indexed: 12/14/2022]
Abstract
Measurement of oxygen consumption is a powerful and uniquely informative experimental technique. It can help identify mitochondrial mechanisms of action following pharmacologic and genetic interventions, and characterize energy metabolism in physiology and disease. The conceptual and practical benefits of respirometry have made it a frontline technique to understand how mitochondrial function can interface with-and in some cases control-cell physiology. Nonetheless, an appreciation of the complexity and challenges involved with such measurements is required to avoid common experimental and analytical pitfalls. Here we provide a practical guide to oxygen consumption measurements covering the selection of experimental models and instrumentation, as well as recommendations for the collection, interpretation and normalization of data. These guidelines are provided with the intention of aiding experimental design and enhancing the overall reputability, transparency and reliability of oxygen consumption measurements.
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Affiliation(s)
- Ajit S Divakaruni
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Martin Jastroch
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
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Heidorn-Czarna M, Heidorn HM, Fernando S, Sanislav O, Jarmuszkiewicz W, Mutzel R, Fisher PR. Chronic Activation of AMPK Induces Mitochondrial Biogenesis through Differential Phosphorylation and Abundance of Mitochondrial Proteins in Dictyostelium discoideum. Int J Mol Sci 2021; 22:ijms222111675. [PMID: 34769115 PMCID: PMC8584165 DOI: 10.3390/ijms222111675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial biogenesis is a highly controlled process that depends on diverse signalling pathways responding to cellular and environmental signals. AMP-activated protein kinase (AMPK) is a critical metabolic enzyme that acts at a central control point in cellular energy homeostasis. Numerous studies have revealed the crucial roles of AMPK in the regulation of mitochondrial biogenesis; however, molecular mechanisms underlying this process are still largely unknown. Previously, we have shown that, in cellular slime mould Dictyostelium discoideum, the overexpression of the catalytic α subunit of AMPK led to enhanced mitochondrial biogenesis, which was accompanied by reduced cell growth and aberrant development. Here, we applied mass spectrometry-based proteomics of Dictyostelium mitochondria to determine the impact of chronically active AMPKα on the phosphorylation state and abundance of mitochondrial proteins and to identify potential protein targets leading to the biogenesis of mitochondria. Our results demonstrate that enhanced mitochondrial biogenesis is associated with variations in the phosphorylation levels and abundance of proteins related to energy metabolism, protein synthesis, transport, inner membrane biogenesis, and cellular signalling. The observed changes are accompanied by elevated mitochondrial respiratory activity in the AMPK overexpression strain. Our work is the first study reporting on the global phosphoproteome profiling of D. discoideum mitochondria and its changes as a response to constitutively active AMPK. We also propose an interplay between the AMPK and mTORC1 signalling pathways in controlling the cellular growth and biogenesis of mitochondria in Dictyostelium as a model organism.
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Affiliation(s)
- Malgorzata Heidorn-Czarna
- Department of Biology, Chemistry, Pharmacy, Institute for Biology-Microbiology, Freie Universität Berlin, 14195 Berlin, Germany; (H.-M.H.); (R.M.)
- Department of Cellular Molecular Biology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
- Correspondence: ; Tel.: +48-71-375-62-73
| | - Herbert-Michael Heidorn
- Department of Biology, Chemistry, Pharmacy, Institute for Biology-Microbiology, Freie Universität Berlin, 14195 Berlin, Germany; (H.-M.H.); (R.M.)
| | - Sanjanie Fernando
- Discipline of Microbiology, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC 3086, Australia; (S.F.); (O.S.); (P.R.F.)
| | - Oana Sanislav
- Discipline of Microbiology, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC 3086, Australia; (S.F.); (O.S.); (P.R.F.)
| | - Wieslawa Jarmuszkiewicz
- Laboratory of Mitochondrial Biochemistry, Department of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznan, Poland;
| | - Rupert Mutzel
- Department of Biology, Chemistry, Pharmacy, Institute for Biology-Microbiology, Freie Universität Berlin, 14195 Berlin, Germany; (H.-M.H.); (R.M.)
| | - Paul R. Fisher
- Discipline of Microbiology, Department of Physiology, Anatomy and Microbiology, School of Life Sciences, College of Science, Health and Engineering, La Trobe University, Bundoora, VIC 3086, Australia; (S.F.); (O.S.); (P.R.F.)
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5
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Rosenbusch KE, Oun A, Sanislav O, Lay ST, Keizer-Gunnink I, Annesley SJ, Fisher PR, Dolga AM, Kortholt A. A Conserved Role for LRRK2 and Roco Proteins in the Regulation of Mitochondrial Activity. Front Cell Dev Biol 2021; 9:734554. [PMID: 34568343 PMCID: PMC8455996 DOI: 10.3389/fcell.2021.734554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/16/2021] [Indexed: 01/02/2023] Open
Abstract
Parkinson's Disease (PD) is the second most common neurodegenerative disease world-wide. Mutations in the multidomain protein Leucine Rich Repeat Kinase 2 (LRRK2) are the most frequent cause of hereditary PD. Furthermore, recent data suggest that independent of mutations, increased kinase activity of LRRK2 plays an essential role in PD pathogenesis. Isolated mitochondria of tissue samples from PD patients carrying LRRK2 mutations display a significant impairment of mitochondrial function. However, due to the complexity of the mitochondrial signaling network, the role of LRRK2 in mitochondrial metabolism is still not well understood. Previously we have shown that D. discoideum Roco4 is a suitable model to study the activation mechanism of LRRK2 in vivo. To get more insight in the LRRK2 pathways regulating mitochondrial activity we used this Roco4 model system in combination with murine RAW macrophages. Here we show that both Dictyostelium roco4 knockout and cells expressing PD-mutants show behavioral and developmental phenotypes that are characteristic for mitochondrial impairment. Mitochondrial activity measured by Seahorse technology revealed that the basal respiration of D. discoideum roco4- cells is significantly increased compared to the WT strain, while the basal and maximal respiration values of cells overexpressing Roco4 are reduced compared to the WT strain. Consistently, LRRK2 KO RAW 264.7 cells exhibit higher maximal mitochondrial respiration activity compared to the LRRK2 parental RAW264.7 cells. Measurement on isolated mitochondria from LRRK2 KO and parental RAW 264.7 cells revealed no difference in activity compared to the parental cells. Furthermore, neither D. discoideum roco4- nor LRRK2 KO RAW 264.7 showed a difference in either the number or the morphology of mitochondria compared to their respective parental strains. This suggests that the observed effects on the mitochondrial respiratory in cells are indirect and that LRRK2/Roco proteins most likely require other cytosolic cofactors to elicit mitochondrial effects.
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Affiliation(s)
| | - Asmaa Oun
- Department of Cell Biochemistry, University of Groningen, Groningen, Netherlands.,Groningen Research Institute of Pharmacy (GRIP), Molecular Pharmacology XB10, Groningen, Netherlands.,Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
| | - Oana Sanislav
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Sui T Lay
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Ineke Keizer-Gunnink
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Sarah J Annesley
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Paul R Fisher
- Department of Physiology Anatomy and Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Amalia M Dolga
- Groningen Research Institute of Pharmacy (GRIP), Molecular Pharmacology XB10, Groningen, Netherlands
| | - Arjan Kortholt
- Department of Cell Biochemistry, University of Groningen, Groningen, Netherlands.,Department of Pharmacology, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey
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Mroczek K, Fernando S, Fisher PR, Annesley SJ. Interactions and Cytotoxicity of Human Neurodegeneration- Associated Proteins Tau and α-Synuclein in the Simple Model Dictyostelium discoideum. Front Cell Dev Biol 2021; 9:741662. [PMID: 34552934 PMCID: PMC8450459 DOI: 10.3389/fcell.2021.741662] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/19/2021] [Indexed: 11/17/2022] Open
Abstract
The abnormal accumulation of the tau protein into aggregates is a hallmark in neurodegenerative diseases collectively known as tauopathies. In normal conditions, tau binds off and on microtubules aiding in their assembly and stability dependent on the phosphorylation state of the protein. In disease-affected neurons, hyperphosphorylation leads to the accumulation of the tau protein into aggregates, mainly neurofibrillary tangles (NFT) which have been seen to colocalise with other protein aggregates in neurodegeneration. One such protein is α-synuclein, the main constituent of Lewy bodies (LB), a hallmark of Parkinson's disease (PD). In many neurodegenerative diseases, including PD, the colocalisation of tau and α-synuclein has been observed, suggesting possible interactions between the two proteins. To explore the cytotoxicity and interactions between these two proteins, we expressed full length human tau and α-synuclein in Dictyostelium discoideum alone, and in combination. We show that tau is phosphorylated in D. discoideum and colocalises closely (within 40 nm) with tubulin throughout the cytoplasm of the cell as well as with α-synuclein at the cortex. Expressing wild type α-synuclein alone caused inhibited growth on bacterial lawns, phagocytosis and intracellular Legionella proliferation rates, but activated mitochondrial respiration and non-mitochondrial oxygen consumption. The expression of tau alone impaired multicellular morphogenesis, axenic growth and phototaxis, while enhancing intracellular Legionella proliferation. Direct respirometric assays showed that tau impairs mitochondrial ATP synthesis and increased the "proton leak," while having no impact on respiratory complex I or II function. In most cases depending on the phenotype, the coexpression of tau and α-synuclein exacerbated (phototaxis, fruiting body morphology), or reversed (phagocytosis, growth on plates, mitochondrial respiratory function, Legionella proliferation) the defects caused by either tau or α-synuclein expressed individually. Proteomics data revealed distinct patterns of dysregulation in strains ectopically expressing tau or α-synuclein or both, but down regulation of expression of cytoskeletal proteins was apparent in all three groups and most evident in the strain expressing both proteins. These results indicate that tau and α-synuclein exhibit different but overlapping patterns of intracellular localisation, that they individually exert distinct but overlapping patterns of cytotoxic effects and that they interact, probably physically in the cell cortex as well as directly or indirectly in affecting some phenotypes. The results show the efficacy of using D. discoideum as a model to study the interaction of proteins involved in neurodegeneration.
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Affiliation(s)
| | | | | | - Sarah J. Annesley
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Bundoora, VIC, Australia
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Chen S, Annesley SJ, Jasim RAF, Fisher PR. The Parkinson's Disease-Associated Protein DJ-1 Protects Dictyostelium Cells from AMPK-Dependent Outcomes of Oxidative Stress. Cells 2021; 10:cells10081874. [PMID: 34440642 PMCID: PMC8392454 DOI: 10.3390/cells10081874] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/17/2021] [Accepted: 07/22/2021] [Indexed: 01/24/2023] Open
Abstract
Mitochondrial dysfunction has been implicated in the pathology of Parkinson’s disease (PD). In Dictyostelium discoideum, strains with mitochondrial dysfunction present consistent, AMPK-dependent phenotypes. This provides an opportunity to investigate if the loss of function of specific PD-associated genes produces cellular pathology by causing mitochondrial dysfunction with AMPK-mediated consequences. DJ-1 is a PD-associated, cytosolic protein with a conserved oxidizable cysteine residue that is important for the protein’s ability to protect cells from the pathological consequences of oxidative stress. Dictyostelium DJ-1 (encoded by the gene deeJ) is located in the cytosol from where it indirectly inhibits mitochondrial respiration and also exerts a positive, nonmitochondrial role in endocytosis (particularly phagocytosis). Its loss in unstressed cells impairs endocytosis and causes correspondingly slower growth, while also stimulating mitochondrial respiration. We report here that oxidative stress in Dictyostelium cells inhibits mitochondrial respiration and impairs phagocytosis in an AMPK-dependent manner. This adds to the separate impairment of phagocytosis caused by DJ-1 knockdown. Oxidative stress also combines with DJ-1 loss in an AMPK-dependent manner to impair or exacerbate defects in phototaxis, morphogenesis and growth. It thereby phenocopies mitochondrial dysfunction. These results support a model in which the oxidized but not the reduced form of DJ-1 inhibits AMPK in the cytosol, thereby protecting cells from the adverse consequences of oxidative stress, mitochondrial dysfunction and the resulting AMPK hyperactivity.
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Affiliation(s)
- Suwei Chen
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
- School of Modern Agriculture and Biotechnology, Ankang University, Ankang 725000, China
| | - Sarah J. Annesley
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
| | - Rasha A. F. Jasim
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
- Department of Laboratory and Clinical Sciences, College of Pharmacy, University of Babylon, Hillah 51002, Iraq
| | - Paul R. Fisher
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia; (S.C.); (S.J.A.); (R.A.F.J.)
- Correspondence: ; Tel.: +61-3-9479-2229
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8
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Cytotoxicity and Mitochondrial Dysregulation Caused by α-Synuclein in Dictyostelium discoideum. Cells 2020; 9:cells9102289. [PMID: 33066427 PMCID: PMC7602147 DOI: 10.3390/cells9102289] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Alpha synuclein has been linked to both sporadic and familial forms of Parkinson’s disease (PD) and is the most abundant protein in Lewy bodies a hallmark of Parkinson’s disease. The function of this protein and the molecular mechanisms underlying its toxicity are still unclear, but many studies have suggested that the mechanism of α-synuclein toxicity involves alterations to mitochondrial function. Here we expressed human α-synuclein and two PD-causing α-synuclein mutant proteins (with a point mutation, A53T, and a C-terminal 20 amino acid truncation) in the eukaryotic model Dictyostelium discoideum. Mitochondrial disease has been well studied in D. discoideum and, unlike in mammals, mitochondrial dysfunction results in a clear set of defective phenotypes. These defective phenotypes are caused by the chronic hyperactivation of the cellular energy sensor, AMP-activated protein kinase (AMPK). Expression of α-synuclein wild type and mutant forms was toxic to the cells and mitochondrial function was dysregulated. Some but not all of the defective phenotypes could be rescued by down regulation of AMPK revealing both AMPK-dependent and -independent mechanisms. Importantly, we also show that the C-terminus of α-synuclein is required and sufficient for the localisation of the protein to the cell cortex in D. discoideum.
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9
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ATP1A3 mutation as a candidate cause of autosomal dominant cone-rod dystrophy. Hum Genet 2020; 139:1391-1401. [PMID: 32440726 DOI: 10.1007/s00439-020-02182-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/08/2020] [Indexed: 10/24/2022]
Abstract
Cone-rod dystrophy (CORD) is an inherited retinal degenerative disease characterized by progressive loss of cone and rod photoreceptors. Although several genes have been reported to cause autosomal dominant CORD (adCORD), the genetic causes of adCORD have not been fully elucidated. Here, we identified the ATP1A3 gene, encoding the α3 subunit of Na+, K+-ATPase, as a novel gene associated with adCORD. Using whole-exome sequencing (WES), we found a candidate mutation of ATP1A3 that co-segregated with the disease in an analysis of two affected patients and one healthy relative in an adCORD family. According to our RNA-seq data, we demonstrated that the Atp1a3 mRNA level was extremely high in the murine retina. Overexpression of mutant ATP1A3 in vitro led to a reduced oxygen consumption rate (OCR), reflecting the limited mitochondrial reserve capacity. Furthermore, we generated transgenic mice expressing the ATP1A3 cDNA with patient variant and found decreased electroretinogram (ERG) responses. Moreover, the mutant ATP1A3 is highly expressed in photoreceptor inner segment, where mitochondria are enriched. These results suggest that the ATP1A3 mutation is a new genetic cause responsible for adCORD and indicate that ATP1A3 plays an important role in retinal function.
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10
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Perry CJ, Warren EC, Damstra-Oddy JL, Storey C, Francione LM, Annesley SJ, Fisher PR, Müller-Taubenberger A, Williams RSB. A Dictyostelium discoideum mitochondrial fluorescent tagging vector that does not affect respiratory function. Biochem Biophys Rep 2020; 22:100751. [PMID: 32258439 PMCID: PMC7109396 DOI: 10.1016/j.bbrep.2020.100751] [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: 01/30/2020] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 02/01/2023] Open
Abstract
Visualizing mitochondria in living Dictyostelium discoideum cells using fluorescent dyes is often problematic due to variability in staining, metabolism of the dyes, and unknown potential effects of the dyes on mitochondrial function. We show that fluorescent labelling of mitochondria, using an N-terminal mitochondrial localization sequence derived from the D. discoideum protein GcvH1 (glycine cleavage system H1) attached to a red fluorescent protein enables clear mitochondrial imaging. We also show that this labelling has no effect upon mitochondria load or respiratory function.
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Affiliation(s)
- Christopher J Perry
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Eleanor C Warren
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Joseph L Damstra-Oddy
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Claire Storey
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Lisa M Francione
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Sarah J Annesley
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Paul R Fisher
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Robin S B Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
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11
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Hao Y, Wu M, Wang J. Fibroblast growth factor-2 ameliorates tumor necrosis factor-alpha-induced osteogenic damage of human bone mesenchymal stem cells by improving oxidative phosphorylation. Mol Cell Probes 2020; 52:101538. [PMID: 32084581 DOI: 10.1016/j.mcp.2020.101538] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 01/30/2020] [Accepted: 02/17/2020] [Indexed: 12/13/2022]
Abstract
Tumor necrosis factor-alpha (TNF-α) has been shown to have an inhibitory effect on the osteogenic differentiation of mesenchymal stem cells. The metabolic switch from glycolysis to oxidative phosphorylation (OXPHOS) is vital for energy supply during osteogenic differentiation. However, the metabolic switch is inhibited under inflammatory stimulation. FGF2 has shown that it can improve osteogenic differentiation and promote autoimmune inflammation. In this study, we investigated whether FGF2 can ameliorate TNF-a-inhibited osteogenic damage by improving OXPHOS. Effects of TNF-α or FGF2 on the proliferation and osteogenic differentiation of hBMSCs were evaluated by MTT assay, qRT-PCR, and ALP activity tests. The function of FGF2 on the TNF-a-inhibited metabolic switch was determined by Mito Stress test. The results showed that TNF-α was able to inhibit the osteogenic differentiation and OXPHOS of hBMSCs. FGF2 has no obvious function in improving the osteogenic-related genes, but it can ameliorate the impaired osteogenesis and OCR value caused by TNF-α. These findings suggest that FGF2 can prevent the impaired osteogenic differentiation and metabolic switch of hBMSCs under inflammatory stimulation, which might enhance the regeneration capacity of hBMSCs.
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Affiliation(s)
- Yishan Hao
- Department of Oral Implantology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China; Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Minting Wu
- Department of Oral Implantology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China; Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Jinming Wang
- Department of Oral Implantology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China; Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China.
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12
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Wenxin Keli Regulates Mitochondrial Oxidative Stress and Homeostasis and Improves Atrial Remodeling in Diabetic Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:2468031. [PMID: 32104528 PMCID: PMC7040409 DOI: 10.1155/2020/2468031] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/07/2020] [Accepted: 01/25/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial dysfunction and oxidative stress play an important role in the pathogenesis of both atrial fibrillation (AF) and diabetes mellitus (DM). Wenxin Keli (WXKL), an antiarrhythmic traditional Chinese medicine, has been shown to prevent cardiac arrhythmias through modulation of cardiac ion channels. This study tested the hypothesis that WXKL can improve atrial remodeling in diabetic rats by restoring mitochondrial function. Primary atrial fibroblasts of neonatal SD rats were divided into four groups: control, hydrogen peroxide (H2O2), H2O2+WXKL 1 g/L, and H2O2+WXKL 3 g/L groups. Intracellular mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and mitochondrial oxygen consumption were measured. SD male rats were randomly divided into three groups: control, DM, and DM+WXKL groups. Rats in the DM+WXKL group were treated with daily gavage of WXKL at 3 g/kg. After eight weeks, echocardiography, hemodynamic examination, histology, electrophysiology study, mitochondrial respiratory function, and western blots were assessed. H2O2 treatment led to increased ROS and decreased intracellular MMP and mitochondrial oxygen consumption in primary atrial fibroblasts. WXKL improved the above changes. DM rats showed increased atrial fibrosis, greater left atrial diameter, lower atrial conduction velocity, higher conduction heterogeneity, higher AF inducibility, and lower mitochondrial protein expression, and all these abnormal changes except for left atrial diameter were improved in the DM+WXKL group. WXKL improves atrial remodeling by regulating mitochondrial function and homeostasis and reducing mitochondrial ROS in diabetic rats.
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13
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Shahul Hameed UF, Sanislav O, Lay ST, Annesley SJ, Jobichen C, Fisher PR, Swaminathan K, Arold ST. Proteobacterial Origin of Protein Arginine Methylation and Regulation of Complex I Assembly by MidA. Cell Rep 2018; 24:1996-2004. [DOI: 10.1016/j.celrep.2018.07.075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/06/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022] Open
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14
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Mitochondrial HTRA2 Plays a Positive, Protective Role in Dictyostelium discoideum but Is Cytotoxic When Overexpressed. Genes (Basel) 2018; 9:genes9070355. [PMID: 30013019 PMCID: PMC6070809 DOI: 10.3390/genes9070355] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 12/20/2022] Open
Abstract
HTRA2 is a mitochondrial protein, mutations in which are associated with autosomal dominant late-onset Parkinson’s disease (PD). The mechanisms by which HTRA2 mutations result in PD are poorly understood. HTRA2 is proposed to play a proteolytic role in protein quality control and homeostasis in the mitochondrial intermembrane space. Its loss has been reported to result in accumulation of unfolded and misfolded proteins. However, in at least one case, PD-associated HTRA2 mutation can cause its hyperphosphorylation, possibly resulting in protease hyperactivity. The consequences of overactive mitochondrial HTRA2 are not clear. Dictyostelium discoideum provides a well-established model for studying mitochondrial dysfunction, such as has been implicated in the pathology of PD. We identified a single homologue of human HTRA2 encoded in the Dictyostelium discoideum genome and showed that it is localized to the mitochondria where it plays a cytoprotective role. Knockdown of HTRA2 expression caused defective morphogenesis in the multicellular phases of the Dictyostelium life cycle. In vegetative cells, it did not impair mitochondrial respiration but nonetheless caused slow growth (particularly when the cells were utilizing a bacterial food source), unaccompanied by significant defects in the requisite endocytic pathways. Despite its protective roles, we could not ectopically overexpress wild type HTRA2, suggesting that mitochondrial HTRA2 hyperactivity is lethal. This toxicity was abolished by replacing the essential catalytic serine S300 with alanine to ablate serine protease activity. Overexpression of protease-dead HTRA2 phenocopied the effects of knockdown, suggesting that the mutant protein competitively inhibits interactions between wild type HTRA2 and its binding partners. Our results show that cytopathological dysfunction can be caused either by too little or too much HTRA2 activity in the mitochondria and suggest that either could be a cause of PD.
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15
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Wheat germ supplementation alleviates insulin resistance and cardiac mitochondrial dysfunction in an animal model of diet-induced obesity. Br J Nutr 2017; 118:241-249. [DOI: 10.1017/s0007114517002082] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractObesity is strongly associated with insulin resistance (IR), along with mitochondrial dysfunction to metabolically active tissues and increased production of reactive O2 species (ROS). Foods rich in antioxidants such as wheat germ (WG), protect tissues from damage due to ROS and modulate some negative effects of obesity. This study examined the effects of WG supplementation on markers of IR, mitochondrial substrate metabolism and innate antioxidant markers in two metabolically active tissues (i.e. liver and heart) of C57BL/6 mice fed a high-fat–high-sucrose (HFS) diet. Male C57BL/6 mice, 6-week-old, were randomised into four dietary treatment groups (n 12 mice/group): control (C, 10 % fat kcal), C+10 % WG, HFS (60 % fat kcal) or HFS+10 % WG (HFS+WG). After 12 weeks of treatment, HFS+WG mice had significantly less visceral fat (−16 %, P=0·006) compared with the HFS group. WG significantly reduced serum insulin (P=0·009), the insulinotropic hormone, gastric inhibitory peptide (P=0·0003), and the surrogate measure of IR, homoeostatic model assessment of IR (P=0·006). HFS diet significantly elevated (45 %, P=0·02) cardiac complex 2 mitochondrial VO2, suggesting increased metabolic stress, whereas WG stabilised this effect to the level of control. Consequently, genes which mediate antioxidant defense and mitochondrial biogenesis (superoxide dismutase 2 (Sod2) and PPARγ coactivator 1-α (Pgc1a), respectively) were significantly reduced (P<0·05) in the heart of the HFS group, whereas WG supplementation tended to up-regulate both genes. WG significantly increased hepatic gene expression of Sod2 (P=0·048) but not Pgc1a. Together, these results showed that WG supplementation in HFS diet, reduced IR and improved cardiac mitochondrial metabolic functions.
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16
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Chen S, Annesley SJ, Jasim RAF, Musco VJ, Sanislav O, Fisher PR. The Parkinson's disease-associated protein DJ-1 plays a positive nonmitochondrial role in endocytosis in Dictyostelium cells. Dis Model Mech 2017; 10:1261-1271. [PMID: 28819044 PMCID: PMC5665451 DOI: 10.1242/dmm.028084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 08/14/2017] [Indexed: 01/01/2023] Open
Abstract
The loss of function of DJ-1 caused by mutations in DJ1 causes a form of familial Parkinson's disease (PD). However, the role of DJ-1 in healthy and in PD cells is poorly understood. Even its subcellular localization in mammalian cells is uncertain, with both cytosolic and mitochondrial locations having been reported. We show here that DJ-1 is normally located in the cytoplasm in healthy Dictyostelium discoideum cells. With its unique life cycle, straightforward genotype-phenotype relationships, experimental accessibility and genetic tractability, D.discoideum offers an attractive model to investigate the roles of PD-associated genes. Furthermore, the study of mitochondrial biology, mitochondrial genome transcription and AMP-activated protein kinase-mediated cytopathologies in mitochondrial dysfunction have been well developed in this organism. Unlike mammalian systems, Dictyostelium mitochondrial dysfunction causes a reproducible and readily assayed array of aberrant phenotypes: defective phototaxis, impaired growth, normal rates of endocytosis and characteristic defects in multicellular morphogenesis. This makes it possible to study whether the underlying cytopathological mechanisms of familial PD involve mitochondrial dysfunction. DJ-1 has a single homologue in the Dictyostelium genome. By regulating the expression level of DJ-1 in D. discoideum, we show here that in unstressed cells, DJ-1 is required for normal rates of endocytic nutrient uptake (phagocytosis and, to a lesser extent, pinocytosis) and thus growth. Reduced expression of DJ-1 had no effect on phototaxis in the multicellular migratory ‘slug’ stage of the life cycle, but resulted in thickened stalks in the final fruiting bodies. This pattern of phenotypes is distinct from that observed in Dictyostelium to result from mitochondrial dyfunction. Direct measurement of mitochondrial respiratory function in intact cells revealed that DJ-1 knockdown stimulates whereas DJ-1 overexpression inhibits mitochondrial activity. Together, our results suggest positive roles for DJ-1 in endocytic pathways and loss-of-function cytopathologies that are not associated with impaired mitochondrial function. Editor's choice: The Dictyostelium homologue of the Parkinson's disease-associated protein DJ-1 is located in the cytosol, and its loss causes cytopathological defects in endocytic and autophagic cell death pathways, but stimulates respiration by functionally normal mitochondrial respiratory complexes.
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Affiliation(s)
- Suwei Chen
- Department of Microbiology, Faculty of Science, Technology and Engineering, La Trobe University, VIC 3086, Australia.,School of Modern Agriculture and Biological Science and Technology, Ankang University, Shaanxi 725000, PRC
| | - Sarah J Annesley
- Department of Microbiology, Faculty of Science, Technology and Engineering, La Trobe University, VIC 3086, Australia
| | - Rasha A F Jasim
- Department of Microbiology, Faculty of Science, Technology and Engineering, La Trobe University, VIC 3086, Australia.,Department of Laboratory and Clinical Sciences, College of Pharmacy, University of Babylon, PO Box 4, Hilla, Iraq
| | - Vanessa J Musco
- Department of Microbiology, Faculty of Science, Technology and Engineering, La Trobe University, VIC 3086, Australia
| | - Oana Sanislav
- Department of Microbiology, Faculty of Science, Technology and Engineering, La Trobe University, VIC 3086, Australia
| | - Paul R Fisher
- Department of Microbiology, Faculty of Science, Technology and Engineering, La Trobe University, VIC 3086, Australia
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