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Cheung G, Lin YC, Papadopoulos V. Translocator protein in the rise and fall of central nervous system neurons. Front Cell Neurosci 2023; 17:1210205. [PMID: 37416505 PMCID: PMC10322222 DOI: 10.3389/fncel.2023.1210205] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
Translocator protein (TSPO), a 18 kDa protein found in the outer mitochondrial membrane, has historically been associated with the transport of cholesterol in highly steroidogenic tissues though it is found in all cells throughout the mammalian body. TSPO has also been associated with molecular transport, oxidative stress, apoptosis, and energy metabolism. TSPO levels are typically low in the central nervous system (CNS), but a significant upregulation is observed in activated microglia during neuroinflammation. However, there are also a few specific regions that have been reported to have higher TSPO levels than the rest of the brain under normal conditions. These include the dentate gyrus of the hippocampus, the olfactory bulb, the subventricular zone, the choroid plexus, and the cerebellum. These areas are also all associated with adult neurogenesis, yet there is no explanation of TSPO's function in these cells. Current studies have investigated the role of TSPO in microglia during neuron degeneration, but TSPO's role in the rest of the neuron lifecycle remains to be elucidated. This review aims to discuss the known functions of TSPO and its potential role in the lifecycle of neurons within the CNS.
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Shin TH, Lee DY, Manavalan B, Basith S, Na YC, Yoon C, Lee HS, Paik MJ, Lee G. Silica-coated magnetic nanoparticles activate microglia and induce neurotoxic D-serine secretion. Part Fibre Toxicol 2021; 18:30. [PMID: 34384435 PMCID: PMC8359100 DOI: 10.1186/s12989-021-00420-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 07/13/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Nanoparticles have been studied for brain imaging, diagnosis, and drug delivery owing to their versatile properties due to their small sizes. However, there are growing concerns that nanoparticles may exert toxic effects in the brain. In this study, we assessed direct nanotoxicity on microglia, the resident macrophages of the central nervous system, and indirect toxicity on neuronal cells exerted by silica-coated magnetic nanoparticles containing rhodamine B isothiocyanate dye [MNPs@SiO2(RITC)]. METHODS We investigated MNPs@SiO2(RITC)-induced biological changes in BV2 murine microglial cells via RNA-sequencing-based transcriptome analysis and gas chromatography-mass spectrometry-based intracellular and extracellular amino acid profiling. Morphological changes were analyzed by transmission electron microscopy. Indirect effects of MNPs@SiO2(RITC) on neuronal cells were assessed by Transwell-based coculture with MNPs@SiO2(RITC)-treated microglia. MNPs@SiO2(RITC)-induced biological changes in the mouse brain in vivo were examined by immunohistochemical analysis. RESULTS BV2 murine microglial cells were morphologically activated and the expression of Iba1, an activation marker protein, was increased after MNPs@SiO2(RITC) treatment. Transmission electron microscopy analysis revealed lysosomal accumulation of MNPs@SiO2(RITC) and the formation of vesicle-like structures in MNPs@SiO2(RITC)-treated BV2 cells. The expression of several genes related to metabolism and inflammation were altered in 100 µg/ml MNPs@SiO2(RITC)-treated microglia when compared with that in non-treated (control) and 10 µg/ml MNPs@SiO2(RITC)-treated microglia. Combined transcriptome and amino acid profiling analyses revealed that the transport of serine family amino acids, including glycine, cysteine, and serine, was enhanced. However, only serine was increased in the growth medium of activated microglia; especially, excitotoxic D-serine secretion from primary rat microglia was the most strongly enhanced. Activated primary microglia reduced intracellular ATP levels and proteasome activity in cocultured neuronal cells, especially in primary cortical neurons, via D-serine secretion. Moreover, ubiquitinated proteins accumulated and inclusion bodies were increased in primary dopaminergic and cortical neurons cocultured with activated primary microglia. In vivo, MNPs@SiO2(RITC), D-serine, and ubiquitin aggresomes were distributed in the MNPs@SiO2(RITC)-treated mouse brain. CONCLUSIONS MNPs@SiO2(RITC)-induced activation of microglia triggers excitotoxicity in neurons via D-serine secretion, highlighting the importance of neurotoxicity mechanisms incurred by nanoparticle-induced microglial activation.
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Affiliation(s)
- Tae Hwan Shin
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Da Yeon Lee
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Balachandran Manavalan
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Shaherin Basith
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
| | - Yun-Cheol Na
- Western Seoul Center, Korea Basic Science Institute, 150 Bugahyeon-ro, 03759 Seoul, Republic of Korea
| | - Cheolho Yoon
- Ochang Center, Korea Basic Science Institute, 162 Yeongudanji-ro, 28119 Cheongju, Republic of Korea
| | - Hyeon-Seong Lee
- College of Pharmacy, Sunchon National University, 255 Jungang-ro, 57922 Suncheon, Republic of Korea
| | - Man Jeong Paik
- College of Pharmacy, Sunchon National University, 255 Jungang-ro, 57922 Suncheon, Republic of Korea
| | - Gwang Lee
- Department of Physiology, Ajou University School of Medicine, 206 World cup-ro, 16499 Suwon, Republic of Korea
- Department of Molecular Science and Technology, Ajou University, 206 World cup-ro, 16499 Suwon, Republic of Korea
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Homoplasmic deleterious MT-ATP6/8 mutations in adult patients. Mitochondrion 2020; 55:64-77. [PMID: 32858252 DOI: 10.1016/j.mito.2020.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/13/2020] [Accepted: 08/14/2020] [Indexed: 01/10/2023]
Abstract
To address the frequency of complex V defects, we systematically sequenced MT-ATP6/8 genes in 512 consecutive patients. We performed functional analysis in muscle or fibroblasts for 12 out of 27 putative homoplasmic mutations and in cybrids for four. Fibroblasts, muscle and cybrids with known deleterious mutations underwent parallel analysis. It included oxidative phosphorylation spectrophotometric assays, western blots, structural analysis, ATP production, glycolysis and cell proliferation evaluation. We demonstrated the deleterious nature of three original mutations. Striking gradation in severity of the mutations consequences and differences between muscle, fibroblasts and cybrids implied a likely under-diagnosis of human complex V defects.
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Kuffner K, Triebelhorn J, Meindl K, Benner C, Manook A, Sudria-Lopez D, Siebert R, Nothdurfter C, Baghai TC, Drexler K, Berneburg M, Rupprecht R, Milenkovic VM, Wetzel CH. Major Depressive Disorder is Associated with Impaired Mitochondrial Function in Skin Fibroblasts. Cells 2020; 9:cells9040884. [PMID: 32260327 PMCID: PMC7226727 DOI: 10.3390/cells9040884] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial malfunction is supposed to be involved in the etiology and pathology of major depressive disorder (MDD). Here, we aimed to identify and characterize the molecular pathomechanisms related to mitochondrial dysfunction in adult human skin fibroblasts, which were derived from MDD patients or non-depressive control subjects. We found that MDD fibroblasts showed significantly impaired mitochondrial functioning: basal and maximal respiration, spare respiratory capacity, non-mitochondrial respiration and adenosine triphosphate (ATP)-related oxygen consumption was lower. Moreover, MDD fibroblasts harbor lower ATP levels and showed hyperpolarized mitochondrial membrane potential. To investigate cellular resilience, we challenged both groups of fibroblasts with hormonal (dexamethasone) or metabolic (galactose) stress for one week, and found that both stressors increased oxygen consumption but lowered ATP content in MDD as well as in non-depressive control fibroblasts. Interestingly, the bioenergetic differences between fibroblasts from MDD or non-depressed subjects, which were observed under non-treated conditions, could not be detected after stress. Our findings support the hypothesis that altered mitochondrial function causes a bioenergetic imbalance, which is associated with the molecular pathophysiology of MDD. The observed alterations in the oxidative phosphorylation system (OXPHOS) and other mitochondria-related properties represent a basis for further investigations of pathophysiological mechanisms and might open new ways to gain insight into antidepressant signaling pathways.
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Affiliation(s)
- Kerstin Kuffner
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Julian Triebelhorn
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Katrin Meindl
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Christoph Benner
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - André Manook
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Daniel Sudria-Lopez
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Ramona Siebert
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Thomas C. Baghai
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Konstantin Drexler
- Department of Dermatology, University Hospital Regensburg, 93053 Regensburg, Germany
| | - Mark Berneburg
- Department of Dermatology, University Hospital Regensburg, 93053 Regensburg, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Vladimir M. Milenkovic
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
| | - Christian H. Wetzel
- Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany; (K.K.); (T.C.B.)
- Correspondence: ; Tel.: +49-941-944-8955
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Angajala A, Lim S, Phillips JB, Kim JH, Yates C, You Z, Tan M. Diverse Roles of Mitochondria in Immune Responses: Novel Insights Into Immuno-Metabolism. Front Immunol 2018; 9:1605. [PMID: 30050539 PMCID: PMC6052888 DOI: 10.3389/fimmu.2018.01605] [Citation(s) in RCA: 260] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/27/2018] [Indexed: 12/20/2022] Open
Abstract
Lack of immune system cells or impairment in differentiation of immune cells is the basis for many chronic diseases. Metabolic changes could be the root cause for this immune cell impairment. These changes could be a result of altered transcription, cytokine production from surrounding cells, and changes in metabolic pathways. Immunity and mitochondria are interlinked with each other. An important feature of mitochondria is it can regulate activation, differentiation, and survival of immune cells. In addition, it can also release signals such as mitochondrial DNA (mtDNA) and mitochondrial ROS (mtROS) to regulate transcription of immune cells. From current literature, we found that mitochondria can regulate immunity in different ways. First, alterations in metabolic pathways (TCA cycle, oxidative phosphorylation, and FAO) and mitochondria induced transcriptional changes can lead to entirely different outcomes in immune cells. For example, M1 macrophages exhibit a broken TCA cycle and have a pro-inflammatory role. By contrast, M2 macrophages undergo β-oxidation to produce anti-inflammatory responses. In addition, amino acid metabolism, especially arginine, glutamine, serine, glycine, and tryptophan, is critical for T cell differentiation and macrophage polarization. Second, mitochondria can activate the inflammatory response. For instance, mitochondrial antiviral signaling and NLRP3 can be activated by mitochondria. Third, mitochondrial mass and mobility can be influenced by fission and fusion. Fission and fusion can influence immune functions. Finally, mitochondria are placed near the endoplasmic reticulum (ER) in immune cells. Therefore, mitochondria and ER junction signaling can also influence immune cell metabolism. Mitochondrial machinery such as metabolic pathways, amino acid metabolism, antioxidant systems, mitochondrial dynamics, mtDNA, mitophagy, and mtROS are crucial for immune functions. Here, we have demonstrated how mitochondria coordinate to alter immune responses and how changes in mitochondrial machinery contribute to alterations in immune responses. A better understanding of the molecular components of mitochondria is necessary. This can help in the development of safe and effective immune therapy or prevention of chronic diseases. In this review, we have presented an updated prospective of the mitochondrial machinery that drives various immune responses.
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Affiliation(s)
- Anusha Angajala
- Center for Cell Death and Metabolism, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States.,Department of Biology, Center for Cancer Research, Tuskegee University, Tuskegee, AL, United States
| | - Sangbin Lim
- Center for Cell Death and Metabolism, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Joshua B Phillips
- Center for Cell Death and Metabolism, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Jin-Hwan Kim
- Center for Cell Death and Metabolism, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
| | - Clayton Yates
- Department of Biology, Center for Cancer Research, Tuskegee University, Tuskegee, AL, United States
| | - Zongbing You
- Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA, United States
| | - Ming Tan
- Center for Cell Death and Metabolism, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, United States
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Biswas J, Gupta S, Verma DK, Gupta P, Singh A, Tiwari S, Goswami P, Sharma S, Singh S. Involvement of glucose related energy crisis and endoplasmic reticulum stress: Insinuation of streptozotocin induced Alzheimer's like pathology. Cell Signal 2018; 42:211-226. [DOI: 10.1016/j.cellsig.2017.10.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/05/2017] [Accepted: 10/30/2017] [Indexed: 11/24/2022]
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Effect of a Fusion Peptide by Covalent Conjugation of a Mitochondrial Cell-Penetrating Peptide and a Glutathione Analog Peptide. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 5:221-231. [PMID: 28567432 PMCID: PMC5437736 DOI: 10.1016/j.omtm.2017.04.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/30/2017] [Indexed: 11/23/2022]
Abstract
Previously, we designed and synthesized a library of mitochondrial antioxidative cell-penetrating peptides (mtCPPs) superior to the parent peptide, SS31, to protect mitochondria from oxidative damage. A library of antioxidative glutathione analogs called glutathione peptides (UPFs), exceptional in hydroxyl radical elimination compared with glutathione, were also designed and synthesized. Here, a follow-up study is described, investigating the effects of the most promising members from both libraries on reactive oxidative species scavenging ability. None of the peptides influenced cell viability at the concentrations used. Fluorescence microscopy studies showed that the fluorescein-mtCPP1-UPF25 (mtgCPP) internalized into cells, and spectrofluorometric analysis determined the presence and extent of peptide into different cell compartments. mtgCPP has superior antioxidative activity compared with mtCPP1 and UPF25 against H2O2 insult, preventing ROS formation by 2- and 3-fold, respectively. Moreover, we neither observed effects on mitochondrial membrane potential nor production of ATP. These data indicate that mtgCPP is targeting mitochondria, protecting them from oxidative damage, while also being present in the cytosol. Our hypothesis is based on a synergistic effect resulting from the fused peptide. The mitochondrial peptide segment is targeting mitochondria, whereas the glutathione analog peptide segment is active in the cytosol, resulting in increased scavenging ability.
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8
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Ding YY, Cheng XR, Li ZQ, Wu SJ, Yang Y, Shi YH, Le GW. Effect of dietary oxidized tyrosine products on insulin secretion via the oxidative stress-induced mitochondria damage in mice pancreas. RSC Adv 2017. [DOI: 10.1039/c7ra02945d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The findings suggested that decreased insulin secretion triggered by OTPs may be mediated by oxidative stress and mitochondrial damage in pancreatic β cells.
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Affiliation(s)
- Yin-Yi Ding
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Xiang-Rong Cheng
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Zhu-Qing Li
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Sha-Ji Wu
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Yuhui Yang
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Yong-Hui Shi
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Guo-Wei Le
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
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Zhu X, Shi D, Li X, Gong W, Wu F, Guo X, Xiao H, Liu L, Zhou H. TLR signalling affects sperm mitochondrial function and motility via phosphatidylinositol 3-kinase and glycogen synthase kinase-3α. Cell Signal 2015; 28:148-156. [PMID: 26658093 DOI: 10.1016/j.cellsig.2015.12.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Revised: 12/03/2015] [Accepted: 12/03/2015] [Indexed: 02/08/2023]
Abstract
Infection in male and female genital tracts can lead to infertility. The underlying mechanisms of this process remain unclear. Toll-like receptors (TLRs) recognize conserved structures and respond to pathogens by initiating signals that activate inflammatory gene transcription. Here, we demonstrate that TLR activation in sperm reduces sperm motility via signalling through myeloid differentiation factor 88 (MyD88), phosphatidylinositol 3-kinase (PI3K), and glycogen synthase kinase (GSK)-3α. Upon TLR activation, phosphorylated forms of PI3K and GSK3α were detected in the mitochondria, and the mitochondrial membrane potential was impaired in sperm. In addition, mitochondrial ATP levels were decreased after TLR agonist stimulation. Furthermore, blocking PI3K or GSK3α activation abrogated these effects and reversed the TLR-induced reduction in sperm motility. These results identify a previously unrecognized TLR signalling pathway that leads to dysfunctional sperm mitochondria, which reduce sperm motility. Our study reveals a novel mechanism by which pathogenic infection affects sperm motility and possibly leads to infertility.
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Affiliation(s)
- Xingxing Zhu
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Dongyan Shi
- Department of Immunology, Nanjing Medical University, Nanjing 210029, China
| | - Xiaoqian Li
- Department of Immunology, Nanjing Medical University, Nanjing 210029, China
| | - Weijuan Gong
- Department of Microbiology & Immunology, Yangzhou University, Yangzhou 225009, China
| | - Fengjiao Wu
- Department of Immunology, Nanjing Medical University, Nanjing 210029, China
| | - Xuejiang Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Hui Xiao
- Institute of Pasteur Shanghai, Chinese Academy of Sciences, Shanghai 200025, China
| | - Lixin Liu
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Hong Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China.
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Bagkos G, Koufopoulos K, Piperi C. A new model for mitochondrial membrane potential production and storage. Med Hypotheses 2014; 83:175-81. [PMID: 24907229 DOI: 10.1016/j.mehy.2014.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 05/10/2014] [Indexed: 02/05/2023]
Abstract
Mitochondrial membrane potential (MMP) is the most reliable indicator of mitochondrial function. The MMP value range of -136 to -140mV has been considered optimal for maximum ATP production for all living organisms. Even small changes from the above range result in a large fall in ATP production and a large increase in ROS production. The resulting bioenergetic deregulation is considered as the causative agent for numerous major human diseases. Normalization of MMP value improves mitochondrial function and gives excellent therapeutic results. In order for a systematic effective treatment of these diseases to be developed, a detailed knowledge of the mechanism of MMP production is absolutely necessary. However, despite the long-standing research efforts, a concrete mechanism for MMP production has not been found yet. The present paper proposes a novel mechanism of MMP production based on new considerations underlying the function of the two basic players of MMP production, the electron transport chain (ETC) and the F1F0 ATP synthase. Under normal conditions, MMP is almost exclusively produced by the electron flow through ETC complexes I-IV, creating a direct electric current that stops in subunit II of complex IV and gradually charges MMP. However, upon ETC dysfunction F1F0 ATP synthase reverses its action and starts to hydrolyze ATP. ATP hydrolysis further produces electric energy which is transferred, in the form of a direct electric current, from F1 to F0 where is used to charge MMP. This new model is expected to redirect current experimental research on mitochondrial bioenergetics and indicate new therapeutic schemes for mitochondrial disorders.
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Affiliation(s)
- Georgios Bagkos
- Department of Biological Chemistry, University of Athens Medical School, Athens, Greece
| | - Kostas Koufopoulos
- Department of Biological Chemistry, University of Athens Medical School, Athens, Greece
| | - Christina Piperi
- Department of Biological Chemistry, University of Athens Medical School, Athens, Greece.
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Liu S, Lee YF, Chou S, Uno H, Li G, Brookes P, Massett MP, Wu Q, Chen LM, Chang C. Mice lacking TR4 nuclear receptor develop mitochondrial myopathy with deficiency in complex I. Mol Endocrinol 2011; 25:1301-10. [PMID: 21622535 DOI: 10.1210/me.2010-0455] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The estimated incidence of mitochondrial diseases in humans is approximately 1:5000 to 1:10,000, whereas the molecular mechanisms for more than 50% of human mitochondrial disease cases still remain unclear. Here we report that mice lacking testicular nuclear receptor 4 (TR4(-/-)) suffered mitochondrial myopathy, and histological examination of TR4(-/-) soleus muscle revealed abnormal mitochondrial accumulation. In addition, increased serum lactate levels, decreased mitochondrial ATP production, and decreased electron transport chain complex I activity were found in TR4(-/-) mice. Restoration of TR4 into TR4(-/-) myoblasts rescued mitochondrial ATP generation capacity and complex I activity. Further real-time PCR quantification and promoter studies found TR4 could modulate complex I activity via transcriptionally regulating the complex I assembly factor NDUFAF1, and restoration of NDUFAF1 level in TR4(-/-) myoblasts increased mitochondrial ATP generation capacity and complex I activity. Together, these results suggest that TR4 plays vital roles in mitochondrial function, which may help us to better understand the pathogenesis of mitochondrial myopathy, and targeting TR4 via its ligands/activators may allow us to develop better therapeutic approaches.
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Affiliation(s)
- Su Liu
- Department of Pathology, University of Rochester, Medical Center, Rochester, New York 14646, USA
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12
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Houstek J, Pícková A, Vojtísková A, Mrácek T, Pecina P, Jesina P. Mitochondrial diseases and genetic defects of ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1400-5. [PMID: 16730639 DOI: 10.1016/j.bbabio.2006.04.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 03/31/2006] [Accepted: 04/04/2006] [Indexed: 11/16/2022]
Abstract
ATP synthase is a key enzyme of mitochondrial energy conversion. In mammals, it produces most of cellular ATP. Alteration of ATP synthase biogenesis may cause two types of isolated defects: qualitative when the enzyme is structurally modified and does not function properly, and quantitative when it is present in insufficient amounts. In both cases the cellular energy provision is impaired, and diminished use of mitochondrial DeltamuH+ promotes ROS production by the mitochondrial respiratory chain. The primary genetic defects have so far been localized in mtDNA ATP6 gene and nuclear ATP12 gene, however, involvement of other nuclear genes is highly probable.
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Affiliation(s)
- Josef Houstek
- Institute of Physiology and Centre for Applied Genomics, Academy of Sciences of the Czech Republic, Vídenská 1083, CZ 142 20 Prague, Czech Republic.
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Labajova A, Vojtiskova A, Krivakova P, Kofranek J, Drahota Z, Houstek J. Evaluation of mitochondrial membrane potential using a computerized device with a tetraphenylphosphonium-selective electrode. Anal Biochem 2006; 353:37-42. [PMID: 16643832 DOI: 10.1016/j.ab.2006.03.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 02/13/2006] [Accepted: 03/17/2006] [Indexed: 11/22/2022]
Abstract
Mitochondrial membrane potential (Deltapsi(m)) plays important roles in the normal function of cells and in pathobiochemical situations. The application of ion-selective electrodes for the measurement of Deltapsi(m) is important for studying normal biological reactions and pathways and mitochondrial diseases. We constructed and optimized a computerized device for real-time monitoring of the Deltapsi(m), which included modification of tetraphenylphosphonium (TPP(+))-selective membrane that improved reproducibility of the TPP(+)-selective electrode. Application of MATLAB software increased the sensitivity of the system. We tested our improved device for membrane potential measurements of isolated mitochondria (in absolute scale of millivolts). In addition, we assessed relative changes of Deltapsi(m) (as changes in TPP(+) concentration) of digitonin-permeabilized cells (hepatocytes, control transmitochondrial cybrids, HeLa G and BSC-40) after addition of substrates, inhibitors, and uncoupler of respiratory chain. Our system can be successfully used for studies of many aspects of the regulation of mitochondrial bioenergetics and as a diagnostic tool for mitochondrial oxidative phosphorylation disorders.
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Affiliation(s)
- Anna Labajova
- Institute of Pathophysiology, 1st Faculty of Medicine, Charles University, Prague, Czech Republic.
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Plásek J, Vojtísková A, Houstek J. Flow-cytometric monitoring of mitochondrial depolarisation: from fluorescence intensities to millivolts. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005; 78:99-108. [PMID: 15664496 DOI: 10.1016/j.jphotobiol.2004.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 09/23/2004] [Accepted: 09/24/2004] [Indexed: 11/16/2022]
Abstract
Redistribution potentiometric dyes represent a powerful tool for monitoring membrane potential of mitochondria, especially when these dyes are used with flow cytometry. In particular, tetramethylrhodamine methyl ester proved to be suitable for the screening of mitochondrial membrane potential in cultured human skin fibroblasts from patients suffering from different defects of oxidative phosphorylation. We have developed a method that makes it possible to measure the changes in mitochondrial membrane potential, or to assess the differences between respective mitochondrial membrane potentials in investigated cells and controls in the absolute scale of millivolts. Our approach employs the fact that a logarithmic transformation of Nernst equation-controlled intensity of fluorescence from potentiometric dyes accumulated in mitochondria leads to a linear scale for mitochondrial membrane potentials.
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Affiliation(s)
- J Plásek
- Faculty of Mathematics and Physics, Institute of Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic.
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Houstek J, Mrácek T, Vojtísková A, Zeman J. Mitochondrial diseases and ATPase defects of nuclear origin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1658:115-21. [PMID: 15282182 DOI: 10.1016/j.bbabio.2004.04.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Revised: 04/01/2004] [Accepted: 04/20/2004] [Indexed: 10/26/2022]
Abstract
Dysfunctions of the F(1)F(o)-ATPase complex cause severe mitochondrial diseases affecting primarily the paediatric population. While in the maternally inherited ATPase defects due to mtDNA mutations in the ATP6 gene the enzyme is structurally and functionally modified, in ATPase defects of nuclear origin mitochondria contain a decreased amount of otherwise normal enzyme. In this case biosynthesis of ATPase is down-regulated due to a block at the early stage of enzyme assembly-formation of the F(1) catalytic part. The pathogenetic mechanism implicates dysfunction of Atp12 or other F(1)-specific assembly factors. For cellular energetics, however, the negative consequences may be quite similar irrespective of whether the ATPase dysfunction is of mitochondrial or nuclear origin.
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Affiliation(s)
- Josef Houstek
- Institute of Physiology and Centre for Integrated Genomics, Academy of Sciences of the Czech Republic, Vídenská 1083, CZ 142 20 Prague 4-Krc, Czech Republic.
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