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Underwood EL, Redell JB, Hood KN, Maynard ME, Hylin M, Waxham MN, Zhao J, Moore AN, Dash PK. Enhanced presynaptic mitochondrial energy production is required for memory formation. Sci Rep 2023; 13:14431. [PMID: 37660191 PMCID: PMC10475119 DOI: 10.1038/s41598-023-40877-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 08/17/2023] [Indexed: 09/04/2023] Open
Abstract
Some of the prominent features of long-term memory formation include protein synthesis, gene expression, enhanced neurotransmitter release, increased excitability, and formation of new synapses. As these processes are critically dependent on mitochondrial function, we hypothesized that increased mitochondrial respiration and dynamics would play a prominent role in memory formation. To address this possibility, we measured mitochondrial oxygen consumption (OCR) in hippocampal tissue punches from trained and untrained animals. Our results show that context fear training significantly increased basal, ATP synthesis-linked, and maximal OCR in the Shaffer collateral-CA1 synaptic region, but not in the CA1 cell body layer. These changes were recapitulated in synaptosomes isolated from the hippocampi of fear-trained animals. As dynamin-related protein 1 (Drp1) plays an important role in mitochondrial fission, we examined its role in the increased mitochondrial respiration observed after fear training. Drp1 inhibitors decreased the training-associated enhancement of OCR and impaired contextual fear memory, but did not alter the number of synaptosomes containing mitochondria. Taken together, our results show context fear training increases presynaptic mitochondria respiration, and that Drp-1 mediated enhanced energy production in CA1 pre-synaptic terminals is necessary for context fear memory that does not result from an increase in the number of synaptosomes containing mitochondria or an increase in mitochondrial mass within the synaptic layer.
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Affiliation(s)
- Erica L Underwood
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
| | - John B Redell
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA.
| | - Kimberly N Hood
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
| | - Mark E Maynard
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
- Department of Electrical and Computer Engineering, University of Houston, Houston, TX, USA
| | - Michael Hylin
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
- Department of Psychology, Southern Illinois University, Carbondale, IL, USA
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
| | - Jing Zhao
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
| | - Anthony N Moore
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
| | - Pramod K Dash
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, P.O. Box 20708, Houston, TX, 77225, USA
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Ahmad F, Ramamorthy S, Areeshi MY, Ashraf GM, Haque S. Isolated Mitochondrial Preparations and In organello Assays: A Powerful and Relevant Ex vivo Tool for Assessment of Brain (Patho)physiology. Curr Neuropharmacol 2023; 21:1433-1449. [PMID: 36872352 PMCID: PMC10324330 DOI: 10.2174/1570159x21666230303123555] [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] [Received: 05/16/2022] [Revised: 10/30/2022] [Accepted: 12/29/2022] [Indexed: 03/07/2023] Open
Abstract
Mitochondria regulate multiple aspects of neuronal development, physiology, plasticity, and pathology through their regulatory roles in bioenergetic, calcium, redox, and cell survival/death signalling. While several reviews have addressed these different aspects, a comprehensive discussion focussing on the relevance of isolated brain mitochondria and their utilities in neuroscience research has been lacking. This is relevant because the employment of isolated mitochondria rather than their in situ functional evaluation, offers definitive evidence of organelle-specificity, negating the interference from extra mitochondrial cellular factors/signals. This mini-review was designed primarily to explore the commonly employed in organello analytical assays for the assessment of mitochondrial physiology and its dysfunction, with a particular focus on neuroscience research. The authors briefly discuss the methodologies for biochemical isolation of mitochondria, their quality assessment, and cryopreservation. Further, the review attempts to accumulate the key biochemical protocols for in organello assessment of a multitude of mitochondrial functions critical for neurophysiology, including assays for bioenergetic activity, calcium and redox homeostasis, and mitochondrial protein translation. The purpose of this review is not to examine each and every method or study related to the functional assessment of isolated brain mitochondria, but rather to assemble the commonly used protocols of in organello mitochondrial research in a single publication. The hope is that this review will provide a suitable platform aiding neuroscientists to choose and apply the required protocols and tools to address their particular mechanistic, diagnostic, or therapeutic question dealing within the confines of the research area of mitochondrial patho-physiology in the neuronal perspective.
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Affiliation(s)
- Faraz Ahmad
- Department of Biotechnology, School of Bio Sciences and Technology (SBST), Vellore Institute of Technology, Vellore, 632014, India
| | - Siva Ramamorthy
- Department of Biotechnology, School of Bio Sciences and Technology (SBST), Vellore Institute of Technology, Vellore, 632014, India
| | - Mohammed Y. Areeshi
- Medical Laboratory Technology Department, College of Applied Medical Sciences, Jazan University, Jazan, 45142, Saudi Arabia
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, 45142, Saudi Arabia
| | - Ghulam Md. Ashraf
- Department of Medical Laboratory Sciences, College of Health Sciences, and Sharjah Institute for Medical Research, University of Sharjah, Sharjah, 27272, United Arab Emirates
| | - Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, 45142, Saudi Arabia
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon
- Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
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3
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Kimoto S, Hashimoto T, Berry KJ, Tsubomoto M, Yamaguchi Y, Enwright JF, Chen K, Kawabata R, Kikuchi M, Kishimoto T, Lewis DA. Expression of actin- and oxidative phosphorylation-related transcripts across the cortical visuospatial working memory network in unaffected comparison and schizophrenia subjects. Neuropsychopharmacology 2022; 47:2061-2070. [PMID: 35034100 PMCID: PMC9556568 DOI: 10.1038/s41386-022-01274-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 11/09/2022]
Abstract
Visuospatial working memory (vsWM), which is impaired in schizophrenia (SZ), is mediated by a distributed cortical network. In one node of this network, the dorsolateral prefrontal cortex (DLPFC), altered expression of transcripts for actin assembly and mitochondrial oxidative phosphorylation (OXPHOS) have been reported in SZ. To understand the relationship between these processes, and the extent to which similar alterations are present in other regions of vsWM network in SZ, a subset of actin- (CDC42, BAIAP2, ARPC3, and ARPC4) and OXPHOS-related (ATP5H, COX4I1, COX7B, and NDUFB3) transcripts were quantified in DLPFC by RNA sequencing in 139 SZ and unaffected comparison (UC) subjects, and in DLPFC and three other regions of the cortical vsWM network by qPCR in 20 pairs of SZ and UC subjects. By RNA sequencing, levels of actin- and OXPHOS-related transcripts were significantly altered in SZ, and robustly correlated in both UC and SZ subject groups. By qPCR, cross-regional expression patterns of these transcripts in UC subjects were consistent with greater actin assembly in DLPFC and higher OXPHOS activity in primary visual cortex (V1). In SZ, CDC42 and ARPC4 levels were lower in all regions, BAIAP2 levels higher only in V1, and ARPC3 levels unaltered across regions. All OXPHOS-related transcript levels were lower in SZ, with the disease effect decreasing from posterior to anterior regions. The differential alterations in markers of actin assembly and energy production across regions of the cortical vsWM network in SZ suggest that each region may make specific contributions to vsWM impairments in the illness.
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Affiliation(s)
- Sohei Kimoto
- Department of Psychiatry, Nara Medical University School of Medicine, Kashihara, 634-8521, Japan
- Department of Neuropsychiatry, Wakayama Medical University School of Medicine, Wakayama, 641-8509, Japan
| | - Takanori Hashimoto
- Department of Psychiatry and Behavioral Science, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Research Center for Child Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Kimberly J Berry
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Makoto Tsubomoto
- Department of Psychiatry and Behavioral Science, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Yasunari Yamaguchi
- Department of Psychiatry, Nara Medical University School of Medicine, Kashihara, 634-8521, Japan
- Department of Neuropsychiatry, Wakayama Medical University School of Medicine, Wakayama, 641-8509, Japan
| | - John F Enwright
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Kehui Chen
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Department of Statistics, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Rika Kawabata
- Department of Psychiatry and Behavioral Science, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Mitsuru Kikuchi
- Department of Psychiatry and Behavioral Science, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
- Research Center for Child Development, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Toshifumi Kishimoto
- Department of Psychiatry, Nara Medical University School of Medicine, Kashihara, 634-8521, Japan
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Department of Statistics, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
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4
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Liu J, Qi J, Chen X, Li Z, Hong B, Ma H, Li G, Shen L, Liu D, Kong Y, Zhai H, Xie Q, Han H, Yang Y. Fear memory-associated synaptic and mitochondrial changes revealed by deep learning-based processing of electron microscopy data. Cell Rep 2022; 40:111151. [PMID: 35926462 DOI: 10.1016/j.celrep.2022.111151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 05/20/2022] [Accepted: 07/11/2022] [Indexed: 11/03/2022] Open
Abstract
Serial section electron microscopy (ssEM) can provide comprehensive 3D ultrastructural information of the brain with exceptional computational cost. Targeted reconstruction of subcellular structures from ssEM datasets is less computationally demanding but still highly informative. We thus developed a region-CNN-based deep learning method to identify, segment, and reconstruct synapses and mitochondria to explore the structural plasticity of synapses and mitochondria in the auditory cortex of mice subjected to fear conditioning. Upon reconstructing over 135,000 mitochondria and 160,000 synapses, we find that fear conditioning significantly increases the number of mitochondria but decreases their size and promotes formation of multi-contact synapses, comprising a single axonal bouton and multiple postsynaptic sites from different dendrites. Modeling indicates that such multi-contact configuration increases the information storage capacity of new synapses by over 50%. With high accuracy and speed in reconstruction, our method yields structural and functional insight into cellular plasticity associated with fear learning.
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Affiliation(s)
- Jing Liu
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Junqian Qi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Xi Chen
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhenchen Li
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Bei Hong
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Hongtu Ma
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Guoqing Li
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Lijun Shen
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Danqian Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu Kong
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hao Zhai
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China
| | - Qiwei Xie
- Research Base of Beijing Modern Manufacturing Development, Beijing University of Technology, Beijing 100124, China.
| | - Hua Han
- National Laboratory of Pattern Recognition, Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China; School of Artificial Intelligence, School of Future Technology, University of the Chinese Academy of Sciences, Beijing 101408, China; Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Yang Yang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
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5
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Amick KA, Mahapatra G, Bergstrom J, Gao Z, Craft S, Register TC, Shively CA, Molina AJA. Brain region-specific disruption of mitochondrial bioenergetics in cynomolgus macaques fed a Western versus a Mediterranean diet. Am J Physiol Endocrinol Metab 2021; 321:E652-E664. [PMID: 34569271 PMCID: PMC8791787 DOI: 10.1152/ajpendo.00165.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitochondrial dysfunction is evident in diseases affecting cognition and metabolism such as Alzheimer's disease and type 2 diabetes. Human studies of brain mitochondrial function are limited to postmortem tissue, preventing the assessment of bioenergetics by respirometry. Here, we investigated the effect of two diets on mitochondrial bioenergetics in three brain regions: the prefrontal cortex (PFC), the entorhinal cortex (ERC), and the cerebellum (CB), using middle-aged nonhuman primates. Eighteen female cynomolgus macaques aged 12.3 ± 0.7 yr were fed either a Mediterranean diet that is associated with healthy outcomes or a Western diet that is associated with poor cognitive and metabolic outcomes. Average bioenergetic capacity within each brain region did not differ between diets. Distinct brain regions have different metabolic requirements related to their function and disease susceptibility. Therefore, we also examined differences in bioenergetic capacity between brain regions. Mitochondria isolated from animals fed a Mediterranean diet maintained distinct differences in mitochondrial bioenergetics between brain regions, whereas animals fed the Western diet had diminished distinction in bioenergetics between brain regions. Notably, fatty acid β-oxidation was not affected between regions in animals fed a Western diet. In addition, bioenergetics in animals fed a Western diet had positive associations with fasting blood glucose and insulin levels in PFC and ERC mitochondria but not in CB mitochondria. Altogether, these data indicate that a Western diet disrupts bioenergetic patterns across brain regions and that circulating blood glucose and insulin levels in Western-diet fed animals influence bioenergetics in brain regions susceptible to Alzheimer's disease and type 2 diabetes.NEW & NOTEWORTHY We show that compared with cynomolgus macaques fed a Mediterranean diet, a Western diet resulted in diminished bioenergetic pattern between brain regions related to blood glucose and insulin levels, specifically in brain regions susceptible to neurodegeneration and diabetes. In addition, fatty acid metabolism not directly linked to the TCA cycle and glucose metabolism did not show differences in bioenergetics due to diet.
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Affiliation(s)
- K Allison Amick
- Section of Gerontology and Geriatrics, Sticht Center for Healthy Aging and Alzheimer's Prevention, Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
- Department of Neuroscience, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Gargi Mahapatra
- Section of Gerontology and Geriatrics, Sticht Center for Healthy Aging and Alzheimer's Prevention, Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Jaclyn Bergstrom
- Department of Family Medicine and Public Health, University of California San Diego School of Medicine, La Jolla, California
| | - Zhengrong Gao
- Section of Gerontology and Geriatrics, Sticht Center for Healthy Aging and Alzheimer's Prevention, Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Suzanne Craft
- Section of Gerontology and Geriatrics, Sticht Center for Healthy Aging and Alzheimer's Prevention, Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Thomas C Register
- Department of Pathology/Comparative Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Carol A Shively
- Department of Pathology/Comparative Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Anthony J A Molina
- Section of Gerontology and Geriatrics, Sticht Center for Healthy Aging and Alzheimer's Prevention, Department of Internal Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina
- Division of Geriatrics and Gerontology, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California
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6
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Mitochondria-Induced Immune Response as a Trigger for Neurodegeneration: A Pathogen from Within. Int J Mol Sci 2021; 22:ijms22168523. [PMID: 34445229 PMCID: PMC8395232 DOI: 10.3390/ijms22168523] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 01/14/2023] Open
Abstract
Symbiosis between the mitochondrion and the ancestor of the eukaryotic cell allowed cellular complexity and supported life. Mitochondria have specialized in many key functions ensuring cell homeostasis and survival. Thus, proper communication between mitochondria and cell nucleus is paramount for cellular health. However, due to their archaebacterial origin, mitochondria possess a high immunogenic potential. Indeed, mitochondria have been identified as an intracellular source of molecules that can elicit cellular responses to pathogens. Compromised mitochondrial integrity leads to release of mitochondrial content into the cytosol, which triggers an unwanted cellular immune response. Mitochondrial nucleic acids (mtDNA and mtRNA) can interact with the same cytoplasmic sensors that are specialized in recognizing genetic material from pathogens. High-energy demanding cells, such as neurons, are highly affected by deficits in mitochondrial function. Notably, mitochondrial dysfunction, neurodegeneration, and chronic inflammation are concurrent events in many severe debilitating disorders. Interestingly in this context of pathology, increasing number of studies have detected immune-activating mtDNA and mtRNA that induce an aberrant production of pro-inflammatory cytokines and interferon effectors. Thus, this review provides new insights on mitochondria-driven inflammation as a potential therapeutic target for neurodegenerative and primary mitochondrial diseases.
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7
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Huntington TE, Srinivasan R. Astrocytic mitochondria in adult mouse brain slices show spontaneous calcium influx events with unique properties. Cell Calcium 2021; 96:102383. [PMID: 33676316 DOI: 10.1016/j.ceca.2021.102383] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/07/2021] [Accepted: 02/21/2021] [Indexed: 12/17/2022]
Abstract
Astrocytes govern critical aspects of brain function via spontaneous calcium signals in their soma and processes. A significant proportion of these spontaneous astrocytic calcium events are associated with mitochondria, however, the extent, sources, or kinetics of astrocytic mitochondrial calcium influx have not been studied in the adult mouse brain. To measure calcium influx into astrocytic mitochondria in situ, we generated an adeno-associated virus (AAV) with the astrocyte-specific GfaABC1D promoter driving expression of the genetically encoded calcium indicator, GCaMP6f tagged to mito7, a mitochondrial matrix targeted signal sequence. Using this construct, we observed AAV-mediated expression of GCaMP6f in adult mouse astrocytic mitochondria that co-localized with MitoTracker deep red (MTDR) in the dorsolateral striatum (DLS) and in the hippocampal stratum radiatum (HPC). Astrocytic mitochondria co-labeled with MTDR and GCaMP6f displayed robust, spontaneous calcium influx events in situ, with subcellular differences in calcium influx kinetics between somatic, branch, and branchlet mitochondria, and inter-regional differences between mitochondria in DLS and HPC astrocytes. Calcium influx into astrocytic mitochondria was strongly dependent on endoplasmic reticulum calcium stores, but did not require the mitochondrial calcium uniporter, MCU. Exposure to either glutamate, D1 or D2 dopamine receptor agonists increased calcium influx in some mitochondria, while simultaneously decreasing calcium influx in other mitochondria from the same astrocyte. These findings show that astrocytic mitochondria possess unique properties with regard to their subcellular morphology, mechanisms of calcium influx, and responses to neurotransmitter receptor agonists. Our results have important implications for understanding the role of astrocytic mitochondria during pathological processes.
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Affiliation(s)
- Taylor E Huntington
- Department of Neuroscience & Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, USA; Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX 77843, USA
| | - Rahul Srinivasan
- Department of Neuroscience & Experimental Therapeutics, Texas A&M College of Medicine, Bryan, TX 77807, USA; Texas A&M Institute for Neuroscience (TAMIN), Texas A&M University, College Station, TX 77843, USA.
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8
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Terburgh K, Coetzer J, Lindeque JZ, van der Westhuizen FH, Louw R. Aberrant BCAA and glutamate metabolism linked to regional neurodegeneration in a mouse model of Leigh syndrome. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166082. [PMID: 33486097 DOI: 10.1016/j.bbadis.2021.166082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/23/2020] [Accepted: 01/16/2021] [Indexed: 02/07/2023]
Abstract
The dysfunction of respiratory chain complex I (CI) is the most common form of mitochondrial disease that most often presents as Leigh syndrome (LS) in children - a severe neurometabolic disorder defined by progressive focal lesions in specific brain regions. The mechanisms underlying this region-specific vulnerability to CI deficiency, however, remain elusive. Here, we examined brain regional respiratory chain enzyme activities and metabolic profiles in a mouse model of LS with global CI deficiency to gain insight into regional vulnerability to neurodegeneration. One lesion-resistant and three lesion-prone brain regions were investigated in Ndufs4 knockout (KO) mice at the late stage of LS. Enzyme assays confirmed significantly decreased (60-80%) CI activity in all investigated KO brain regions, with the lesion-resistant region displaying the highest residual CI activity (38% of wild type). A higher residual CI activity, and a less perturbed NADH/NAD+ ratio, correlate with less severe metabolic perturbations in KO brain regions. Moreover, less perturbed BCAA oxidation and increased glutamate oxidation seem to distinguish lesion-resistant from -prone KO brain regions, thereby identifying key areas of metabolism to target in future therapeutic intervention studies.
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Affiliation(s)
- Karin Terburgh
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Janeé Coetzer
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Jeremy Z Lindeque
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Francois H van der Westhuizen
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Roan Louw
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa.
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9
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Gella A, Prada-Dacasa P, Carrascal M, Urpi A, González-Torres M, Abian J, Sanz E, Quintana A. Mitochondrial Proteome of Affected Glutamatergic Neurons in a Mouse Model of Leigh Syndrome. Front Cell Dev Biol 2020; 8:660. [PMID: 32850799 PMCID: PMC7399339 DOI: 10.3389/fcell.2020.00660] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 07/01/2020] [Indexed: 01/03/2023] Open
Abstract
Defects in mitochondrial function lead to severe neuromuscular orphan pathologies known as mitochondrial disease. Among them, Leigh Syndrome is the most common pediatric presentation, characterized by symmetrical brain lesions, hypotonia, motor and respiratory deficits, and premature death. Mitochondrial diseases are characterized by a marked anatomical and cellular specificity. However, the molecular determinants for this susceptibility are currently unknown, hindering the efforts to find an effective treatment. Due to the complex crosstalk between mitochondria and their supporting cell, strategies to assess the underlying alterations in affected cell types in the context of mitochondrial dysfunction are critical. Here, we developed a novel virus-based tool, the AAV-mitoTag viral vector, to isolate mitochondria from genetically defined cell types. Expression of the AAV-mitoTag in the glutamatergic vestibular neurons of a mouse model of Leigh Syndrome lacking the complex I subunit Ndufs4 allowed us to assess the proteome and acetylome of a subset of susceptible neurons in a well characterized model recapitulating the human disease. Our results show a marked reduction of complex I N-module subunit abundance and an increase in the levels of the assembly factor NDUFA2. Transiently associated non-mitochondrial proteins such as PKCδ, and the complement subcomponent C1Q were also increased in Ndufs4-deficient mitochondria. Furthermore, lack of Ndufs4 induced ATP synthase complex and pyruvate dehydrogenase (PDH) subunit hyperacetylation, leading to decreased PDH activity. We provide novel insight on the pathways involved in mitochondrial disease, which could underlie potential therapeutic approaches for these pathologies.
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Affiliation(s)
- Alejandro Gella
- Mitochondrial Neuropathology Lab, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Patricia Prada-Dacasa
- Mitochondrial Neuropathology Lab, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Cellular Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Montserrat Carrascal
- Proteomics Laboratory CSIC/UAB, Institute of Biomedical Research of Barcelona, Spanish National Research Council (IIBB-CSIC/IDIBAPS), Barcelona, Spain
| | - Andrea Urpi
- Mitochondrial Neuropathology Lab, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Melania González-Torres
- Mitochondrial Neuropathology Lab, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Joaquin Abian
- Proteomics Laboratory CSIC/UAB, Institute of Biomedical Research of Barcelona, Spanish National Research Council (IIBB-CSIC/IDIBAPS), Barcelona, Spain
| | - Elisenda Sanz
- Mitochondrial Neuropathology Lab, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Cellular Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Albert Quintana
- Mitochondrial Neuropathology Lab, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Cellular Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
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10
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Balasubramanian N, Srivastava A, Pawar N, Sagarkar S, Sakharkar AJ. Repeated mild traumatic brain injury induces persistent variations in mitochondrial DNA copy number in mesocorticolimbic neurocircuitry of the rat. Neurosci Res 2020; 155:34-42. [DOI: 10.1016/j.neures.2019.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 12/18/2022]
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11
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Parent M, Chitturi J, Santhakumar V, Hyder F, Sanganahalli BG, Kannurpatti SS. Kaempferol Treatment after Traumatic Brain Injury during Early Development Mitigates Brain Parenchymal Microstructure and Neural Functional Connectivity Deterioration at Adolescence. J Neurotrauma 2020; 37:966-974. [PMID: 31830867 PMCID: PMC7175625 DOI: 10.1089/neu.2019.6486] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Targeting mitochondrial ion homeostasis using Kaempferol, a mitochondrial Ca2+ uniporter channel activator, improves energy metabolism and behavior soon after a traumatic brain injury (TBI) in developing rats. Because of broad TBI pathophysiology and brain mitochondrial heterogeneity, Kaempferol-mediated early-stage behavioral and brain metabolic benefits may accrue from diverse sources within the brain. We hypothesized that Kaempferol influences TBI outcome by differentially impacting the neural, vascular, and synaptic/axonal compartments. After TBI at early development (P31), functional magnetic resonance imaging and diffusion tensor imaging (DTI) were applied to determine imaging outcomes at adolescence (2 months post-injury). Vehicle and Kaempferol treatments were made at 1, 24, and 48 h post-TBI, and their effects were assessed at adolescence. A significant increase in neural connectivity was observed after Kaempferol treatment as assessed by the spatial extent and strength of the somatosensory cortical and hippocampal resting-state functional connectivity (RSFC) networks. However, no significant RSFC changes were observed in the thalamus. DTI measures of fractional anisotropy (FA) and apparent diffusion coefficient, representing synaptic/axonal and microstructural integrity, showed significant improvements after Kaempferol treatment, with highest changes in the frontal and parietal cortices and hippocampus. Kaempferol treatment also increased corpus callosal FA, indicating measurable improvement in the interhemispheric structural connectivity. TBI prognosis was significantly altered at adolescence by early Kaempferol treatment, with improved neural connectivity, neurovascular coupling, and parenchymal microstructure in select brain regions. However, Kaempferol failed to improve vasomotive function across the whole brain, as measured by cerebrovascular reactivity. The differential effects of Kaempferol treatment on various brain functional compartments support diverse cellular-level mitochondrial functional outcomes in vivo.
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Affiliation(s)
- Maxime Parent
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Jyothsna Chitturi
- Department of Radiology, Rutgers Biomedical and Health Sciences–New Jersey Medical School, Newark, New Jersey
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical and Health Sciences-New Jersey Medical School, Medical Science Building, Newark, New Jersey
- Department of Molecular, Cell and Systems Neuroscience, University of California at Riverside, Riverside, California
| | - Fahmeed Hyder
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Basavaraju G. Sanganahalli
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut
| | - Sridhar S. Kannurpatti
- Department of Radiology, Rutgers Biomedical and Health Sciences–New Jersey Medical School, Newark, New Jersey
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12
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Mitochondrial Bioenergetics in Brain Following Ozone Exposure in Rats Maintained on Coconut, Fish and Olive Oil-Rich Diets. Int J Mol Sci 2019; 20:ijms20246303. [PMID: 31847143 PMCID: PMC6941048 DOI: 10.3390/ijms20246303] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
Dietary supplementation with omega-3 and omega-6 fatty acids offer cardioprotection against air pollution, but these protections have not been established in the brain. We tested whether diets rich in omega-3 or -6 fatty acids offered neuroprotective benefits, by measuring mitochondrial complex enzyme I, II and IV activities and oxidative stress measures in the frontal cortex, cerebellum, hypothalamus, and hippocampus of male rats that were fed either a normal diet, or a diet enriched with fish oil olive oil, or coconut oil followed by exposure to either filtered air or ozone (0.8 ppm) for 4 h/day for 2 days. Results show that mitochondrial complex I enzyme activity was significantly decreased in the cerebellum, hypothalamus and hippocampus by diets. Complex II enzyme activity was significantly lower in frontal cortex and cerebellum of rats maintained on all test diets. Complex IV enzyme activity was significantly lower in the frontal cortex, hypothalamus and hippocampus of animals maintained on fish oil. Ozone exposure decreased complex I and II activity in the cerebellum of rats maintained on the normal diet, an effect blocked by diet treatments. While diet and ozone have no apparent influence on endogenous reactive oxygen species production, they do affect antioxidant levels in the brain. Fish oil was the only diet that ozone exposure did not alter. Microglial morphology and GFAP immunoreactivity were assessed across diet groups; results indicated that fish oil consistently decreased reactive microglia in the hypothalamus and hippocampus. These results indicate that acute ozone exposure alters mitochondrial bioenergetics in brain and co-treatment with omega-6 and omega-3 fatty acids alleviate some adverse effects within the brain.
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13
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Schmiesing J, Storch S, Dörfler AC, Schweizer M, Makrypidi-Fraune G, Thelen M, Sylvester M, Gieselmann V, Meyer-Schwesinger C, Koch-Nolte F, Tidow H, Mühlhausen C, Waheed A, Sly WS, Braulke T. Disease-Linked Glutarylation Impairs Function and Interactions of Mitochondrial Proteins and Contributes to Mitochondrial Heterogeneity. Cell Rep 2019; 24:2946-2956. [PMID: 30208319 DOI: 10.1016/j.celrep.2018.08.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 06/20/2018] [Accepted: 08/06/2018] [Indexed: 01/13/2023] Open
Abstract
Lysine glutarylation (Kglu) of mitochondrial proteins is associated with glutaryl-CoA dehydrogenase (GCDH) deficiency, which impairs lysine/tryptophan degradation and causes destruction of striatal neurons during catabolic crisis with subsequent movement disability. By investigating the role of Kglu modifications in this disease, we compared the brain and liver glutarylomes of Gcdh-deficient mice. In the brain, we identified 73 Kglu sites on 37 mitochondrial proteins involved in various metabolic degradation pathways. Ultrastructural immunogold studies indicated that glutarylated proteins are heterogeneously distributed in mitochondria, which are exclusively localized in glial cells. In liver cells, all mitochondria contain Kglu-modified proteins. Glutarylation reduces the catalytic activities of the most abundant glutamate dehydrogenase (GDH) and the brain-specific carbonic anhydrase 5b and interferes with GDH-protein interactions. We propose that Kglu contributes to the functional heterogeneity of mitochondria and may metabolically adapt glial cells to the activity and metabolic demands of neighboring GCDH-deficient neurons.
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Affiliation(s)
- Jessica Schmiesing
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Stephan Storch
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Ann-Cathrin Dörfler
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Michaela Schweizer
- Center of Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Georgia Makrypidi-Fraune
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Melanie Thelen
- Institute of Biochemistry and Molecular Biology, University of Bonn, 53115 Bonn, Germany
| | - Marc Sylvester
- Institute of Biochemistry and Molecular Biology, University of Bonn, 53115 Bonn, Germany
| | - Volkmar Gieselmann
- Institute of Biochemistry and Molecular Biology, University of Bonn, 53115 Bonn, Germany
| | - Catherine Meyer-Schwesinger
- Department of Internal Medicine III, Nephrology and Rheumatology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Henning Tidow
- The Hamburg Center for Ultrafast Imaging & Department Chemistry, University Hamburg, 20146 Hamburg, Germany
| | - Chris Mühlhausen
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Abdul Waheed
- Department of Biochemistry and Molecular Biology, Edward A. Doisy Research Center, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - William S Sly
- Department of Biochemistry and Molecular Biology, Edward A. Doisy Research Center, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Thomas Braulke
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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14
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Santuy A, Turégano-López M, Rodríguez JR, Alonso-Nanclares L, DeFelipe J, Merchán-Pérez A. A Quantitative Study on the Distribution of Mitochondria in the Neuropil of the Juvenile Rat Somatosensory Cortex. Cereb Cortex 2019; 28:3673-3684. [PMID: 30060007 PMCID: PMC6132283 DOI: 10.1093/cercor/bhy159] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/14/2018] [Indexed: 12/17/2022] Open
Abstract
Mitochondria play a key role in energy production and calcium buffering, among many other functions. They provide most of the energy required by neurons, and they are transported along axons and dendrites to the regions of higher energy demands. We have used focused ion beam milling and scanning electron microscopy (FIB/SEM) to obtain stacks of serial sections from the somatosensory cortex of the juvenile rat. We have estimated the volume fraction occupied by mitochondria and their distribution between dendritic, axonal, and nonsynaptic processes. The volume fraction of mitochondria increased from layer I (4.59%) to reach its maximum in layer IV (7.74%) and decreased to its minimum in layer VI (4.03%). On average, 44% of mitochondrial volume was located in dendrites, 15% in axons and 41% in nonsynaptic elements. Given that dendrites, axons, and nonsynaptic elements occupied 38%, 23%, and 39% of the neuropil, respectively, it can be concluded that dendrites are proportionally richer in mitochondria with respect to axons, supporting the notion that most energy consumption takes place at the postsynaptic side. We also found a positive correlation between the volume fraction of mitochondria located in neuronal processes and the density of synapses.
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Affiliation(s)
- A Santuy
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - M Turégano-López
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - J R Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - L Alonso-Nanclares
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - J DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - A Merchán-Pérez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain.,Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, Boadilla del Monte, Madrid, Spain
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15
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Goldman SL, MacKay M, Afshinnekoo E, Melnick AM, Wu S, Mason CE. The Impact of Heterogeneity on Single-Cell Sequencing. Front Genet 2019; 10:8. [PMID: 30881372 PMCID: PMC6405636 DOI: 10.3389/fgene.2019.00008] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 01/09/2019] [Indexed: 12/28/2022] Open
Abstract
The importance of diversity and cellular specialization is clear for many reasons, from population-level diversification, to improved resiliency to unforeseen stresses, to unique functions within metazoan organisms during development and differentiation. However, the level of cellular heterogeneity is just now becoming clear through the integration of genome-wide analyses and more cost effective Next Generation Sequencing (NGS). With easy access to single-cell NGS (scNGS), new opportunities exist to examine different levels of gene expression and somatic mutational heterogeneity, but these assays can generate yottabyte scale data. Here, we model the importance of heterogeneity for large-scale analysis of scNGS data, with a focus on the utilization in oncology and other diseases, providing a guide to aid in sample size and experimental design.
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Affiliation(s)
- Samantha L Goldman
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States.,The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, United States
| | - Matthew MacKay
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States.,The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, United States
| | - Ebrahim Afshinnekoo
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States.,The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, United States.,WorldQuant Initiative for Quantitative Prediction, Weill Cornell Medicine, New York, NY, United States
| | - Ari M Melnick
- Department of Medicine, Weill Cornell Medicine, New York, NY, United States
| | - Shuxiu Wu
- Hangzhou Cancer Institute, Hangzhou Cancer Hospital, Hangzhou, China.,Department of Radiation Oncology, Hangzhou Cancer Hospital, Hangzhou, China
| | - Christopher E Mason
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, United States.,The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Cornell Medicine, New York, NY, United States.,WorldQuant Initiative for Quantitative Prediction, Weill Cornell Medicine, New York, NY, United States.,The Feil Family Brain and Mind Research Institute, New York, NY, United States
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16
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Andersen JV, Jakobsen E, Waagepetersen HS, Aldana BI. Distinct differences in rates of oxygen consumption and ATP synthesis of regionally isolated non-synaptic mouse brain mitochondria. J Neurosci Res 2019; 97:961-974. [PMID: 30675904 DOI: 10.1002/jnr.24371] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 02/06/2023]
Abstract
Brain mitochondrial dysfunction has been implicated in several neurodegenerative diseases. The distribution and efficiency of mitochondria display large heterogeneity throughout the regions of the brain. This may imply that the selective regional susceptibility of neurodegenerative diseases could be mediated through inherent differences in regional mitochondrial function. To investigate regional cerebral mitochondrial energetics, the rates of oxygen consumption and adenosine-5'-triphosphate (ATP) synthesis were assessed in isolated non-synaptic mitochondria of the cerebral cortex, hippocampus, and striatum of the male mouse brain. Oxygen consumption rates were assessed using a Seahorse XFe96 analyzer and ATP synthesis rates were determined by an online luciferin-luciferase coupled luminescence assay. Complex I- and complex II-driven respiration and ATP synthesis, were investigated by applying pyruvate in combination with malate, or succinate, as respiratory substrates, respectively. Hippocampal mitochondria exhibited the lowest basal and adenosine-5'-diphosphate (ADP)-stimulated rate of oxygen consumption when provided pyruvate and malate. However, hippocampal mitochondria also exhibited an increased proton leak and an elevated relative rate of oxygen consumption in response to the uncoupler carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), showing a large capacity for uncoupled respiration in the presence of pyruvate. When the complex II-linked substrate succinate was provided, striatal mitochondria exhibited the highest respiration and ATP synthesis rate, whereas hippocampal mitochondria had the lowest. However, the mitochondrial efficiency, determined as ATP produced/O2 consumed, was similar between the three regions. This study reveals inherent differences in regional mitochondrial energetics and may serve as a tool for further investigations of regional mitochondrial function in relation to neurodegenerative diseases.
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Affiliation(s)
- Jens V Andersen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Emil Jakobsen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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17
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Gonçalves DF, Courtes AA, Hartmann DD, da Rosa PC, Oliveira DM, Soares FAA, Dalla Corte CL. 6-Hydroxydopamine induces different mitochondrial bioenergetics response in brain regions of rat. Neurotoxicology 2018; 70:1-11. [PMID: 30359634 DOI: 10.1016/j.neuro.2018.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/07/2018] [Accepted: 10/10/2018] [Indexed: 11/30/2022]
Abstract
Mitochondrial dysfunction has been demonstrated to have a central role in Parkinson Disease (PD) pathophysiology. Some studies have indicated that PD causes an impairment in mitochondrial bioenergetics; however, the effects of PD on brain-region specific bioenergetics was never investigated before. This study aimed to evaluate mitochondrial bioenergetics in different rat brain structures in an in vitro model of PD using 6-OHDA. Rat brain slices of hippocampus, striatum, and cortex were exposed to 6-OHDA (100 μM) for 1 h and mitochondrial bioenergetic parameters, peroxide production, lactate dehydrogenase (LDH) and citrate synthase (CS) activities were analyzed. Hippocampus slices exposed to 6-OHDA presented increased peroxide production but, no mitochondrial adaptive response against 6-OHDA damage. Cortex slices exposed to 6-OHDA presented increased oxygen flux related to oxidative phosphorylation and energetic pathways exchange demonstrated by the increase in LDH activity, suggesting a mitochondrial compensatory response. Striatum slices exposed to 6-OHDA presented a decrease of oxidative phosphorylation and decrease of oxygen flux related to ATP-synthase indicating an impairment in the respiratory chain. The co-incubation of 6-OHDA with n-acetylcysteine (NAC) abolished the effects of 6-OHDA on mitochondrial function in all brain regions tested, indicating that the increased reactive oxygen species (ROS) production is responsible for the alterations observed in mitochondrial bioenergetics. The present results indicate a brain-region specific response against 6-OHDA, providing new insights into brain mitochondrial bioenergetic function in PD. These findings may contribute to the development of future therapies with a target on energy metabolism.
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Affiliation(s)
- Débora F Gonçalves
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Aline A Courtes
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Diane D Hartmann
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Pamela C da Rosa
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Débora M Oliveira
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Félix A A Soares
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Cristiane L Dalla Corte
- Universidade Federal de Santa Maria, Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Camobi, 97105-900, Santa Maria, RS, Brazil; Universidade Federal do Pampa - Campus Caçapava do Sul, 96570-000, Caçapava do Sul, RS, Brazil.
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18
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Abstract
This review systematically examines the evidence for shifts in flux through energy generating biochemical pathways in Huntington’s disease (HD) brains from humans and model systems. Compromise of the electron transport chain (ETC) appears not to be the primary or earliest metabolic change in HD pathogenesis. Rather, compromise of glucose uptake facilitates glucose flux through glycolysis and may possibly decrease flux through the pentose phosphate pathway (PPP), limiting subsequent NADPH and GSH production needed for antioxidant protection. As a result, oxidative damage to key glycolytic and tricarboxylic acid (TCA) cycle enzymes further restricts energy production so that while basal needs may be met through oxidative phosphorylation, those of excessive stimulation cannot. Energy production may also be compromised by deficits in mitochondrial biogenesis, dynamics or trafficking. Restrictions on energy production may be compensated for by glutamate oxidation and/or stimulation of fatty acid oxidation. Transcriptional dysregulation generated by mutant huntingtin also contributes to energetic disruption at specific enzymatic steps. Many of the alterations in metabolic substrates and enzymes may derive from normal regulatory feedback mechanisms and appear oscillatory. Fine temporal sequencing of the shifts in metabolic flux and transcriptional and expression changes associated with mutant huntingtin expression remain largely unexplored and may be model dependent. Differences in disease progression among HD model systems at the time of experimentation and their varying states of metabolic compensation may explain conflicting reports in the literature. Progressive shifts in metabolic flux represent homeostatic compensatory mechanisms that maintain the model organism through presymptomatic and symptomatic stages.
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Affiliation(s)
- Janet M Dubinsky
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
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19
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Chan SHH, Chan JYH. Mitochondria and Reactive Oxygen Species Contribute to Neurogenic Hypertension. Physiology (Bethesda) 2018; 32:308-321. [PMID: 28615314 DOI: 10.1152/physiol.00006.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/05/2017] [Accepted: 04/13/2017] [Indexed: 02/07/2023] Open
Abstract
Beyond its primary role as fuel generators, mitochondria are engaged in a variety of cellular processes, including redox homeostasis. Mitochondrial dysfunction, therefore, may have a profound impact on high-energy-demanding organs such as the brain. Here, we review the roles of mitochondrial biogenesis and bioenergetics, and their associated signaling in cellular redox homeostasis, and illustrate their contributions to the oxidative stress-related neural mechanism of hypertension, focusing on specific brain areas that are involved in the generation or modulation of sympathetic outflows to the cardiovascular system. We also highlight future challenges of research on mitochondrial physiology and pathophysiology.
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Affiliation(s)
- Samuel H H Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Julie Y H Chan
- Institute for Translational Research in Biomedicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
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20
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Dias C, Lourenço CF, Barbosa RM, Laranjinha J, Ledo A. Analysis of respiratory capacity in brain tissue preparations: high-resolution respirometry for intact hippocampal slices. Anal Biochem 2018; 551:43-50. [PMID: 29753719 DOI: 10.1016/j.ab.2018.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/02/2018] [Accepted: 05/10/2018] [Indexed: 12/13/2022]
Abstract
The evaluation of mitochondrial function provides the basis for the study of brain bioenergetics. However, analysis of brain mitochondrial respiration has been hindered by the low yield associated with mitochondria isolation procedures. Furthermore, isolating mitochondria or cells results in loss of the inherent complexity of the central nervous system. High-resolution respirometry (HRR), is a valuable tool to study mitochondrial function and has been used in diverse biological preparations ranging from isolated mitochondria to tissue homogenates and permeabilized tissue biopsies. Here we describe a novel methodology for evaluation of mitochondrial respiration using tissue preparations from the central nervous system, namely acute hippocampal slices from rodents, with HRR. By using acute intact hippocampal slices, tissue cytoarchitecture, intercellular communication and connectivity are preserved. Mitochondrial respiration was evaluated by using an adapted substrate-uncoupler-inhibitor titration (SUIT) protocol and the expected responses were observed. This methodology can be used to detect differences in mitochondrial function at the oxidative phosphorylation level and for studies with different brain oxidative substrates in physiological and neuropathological settings, by using a system that better represents the in vivo conditions than isolated mitochondria and/or cells.
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Affiliation(s)
- Cândida Dias
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Portugal
| | - Ana Ledo
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.
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21
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Ahmad F, Salahuddin M, Alamoudi W, Acharya S. Dysfunction of cortical synapse-specific mitochondria in developing rats exposed to lead and its amelioration by ascorbate supplementation. Neuropsychiatr Dis Treat 2018; 14:813-824. [PMID: 29606875 PMCID: PMC5868605 DOI: 10.2147/ndt.s148248] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Lead (Pb) is a widespread environmental neurotoxin and its exposure even in minute quantities can lead to compromised neuronal functions. A developing brain is particularly vulnerable to Pb mediated toxicity and early-life exposure leads to permanent alterations in brain development and neuronal signaling and plasticity, culminating into cognitive and behavioral dysfunctions and elevated risk of neuropsychiatric disorders later in life. Nevertheless, the underlying biochemical mechanisms have not been completely discerned. METHODS Because of their ability to fulfill high energy needs and to act as calcium buffers in events of high intensity neuronal activity as well as their adaptive regulatory capability to match the requirements of the dynamicity of synaptic signaling, synapse-specific or synaptic mitochondria (SM) are critical for synaptic development, function and plasticity. Our aim for the present study hence was to characterize the effects of early-life Pb exposure on the functions of SM of prepubertal rats. For this purpose, employing a chronic model of Pb neurotoxicity, we exposed rat pups perinatally and postnatally to Pb and used a plethora of colorimetric and fluorometric assays for assessing redox and bioenergetic properties of SM. In addition, taking advantage of its ability as an antioxidant and as a metal chelator, we employed ascorbic acid (vitamin C) supplementation as an ameliorative therapeutic strategy against Pb-induced neurotoxicity and dysfunction of SM. RESULTS Our results suggest that early-life exposure to Pb leads to elevated oxidative stress in cortical SM with consequent compromises in its energy metabolism activity. Ascorbate supplementation resulted in significant recovery of Pb-induced oxidative stress and functional compromise of SM. CONCLUSION Alterations in redox status and bioenergetic properties of SM could potentially contribute to the synaptic dysfunction observed in events of Pb neurotoxicity. Additionally, our study provides evidence for suitability of ascorbate as a significant ameliorative agent in tacking Pb neurotoxicity.
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Affiliation(s)
- Faraz Ahmad
- Department of Public Health, College of Public Health, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia.,Neuroscience Department, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Mohammad Salahuddin
- Animal House Department, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Widyan Alamoudi
- Neuroscience Department, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Sadananda Acharya
- Department of Public Health, College of Public Health, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
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22
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Leaw B, Nair S, Lim R, Thornton C, Mallard C, Hagberg H. Mitochondria, Bioenergetics and Excitotoxicity: New Therapeutic Targets in Perinatal Brain Injury. Front Cell Neurosci 2017; 11:199. [PMID: 28747873 PMCID: PMC5506196 DOI: 10.3389/fncel.2017.00199] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/26/2017] [Indexed: 12/30/2022] Open
Abstract
Injury to the fragile immature brain is implicated in the manifestation of long-term neurological disorders, including childhood disability such as cerebral palsy, learning disability and behavioral disorders. Advancements in perinatal practice and improved care mean the majority of infants suffering from perinatal brain injury will survive, with many subtle clinical symptoms going undiagnosed until later in life. Hypoxic-ischemia is the dominant cause of perinatal brain injury, and constitutes a significant socioeconomic burden to both developed and developing countries. Therapeutic hypothermia is the sole validated clinical intervention to perinatal asphyxia; however it is not always neuroprotective and its utility is limited to developed countries. There is an urgent need to better understand the molecular pathways underlying hypoxic-ischemic injury to identify new therapeutic targets in such a small but critical therapeutic window. Mitochondria are highly implicated following ischemic injury due to their roles as the powerhouse and main energy generators of the cell, as well as cell death processes. While the link between impaired mitochondrial bioenergetics and secondary energy failure following loss of high-energy phosphates is well established after hypoxia-ischemia (HI), there is emerging evidence that the roles of mitochondria in disease extend far beyond this. Indeed, mitochondrial turnover, including processes such as mitochondrial biogenesis, fusion, fission and mitophagy, affect recovery of neurons after injury and mitochondria are involved in the regulation of the innate immune response to inflammation. This review article will explore these mitochondrial pathways, and finally will summarize past and current efforts in targeting these pathways after hypoxic-ischemic injury, as a means of identifying new avenues for clinical intervention.
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Affiliation(s)
- Bryan Leaw
- The Ritchie Centre, Hudson Institute of Medical ResearchClayton, VIC, Australia
| | - Syam Nair
- Perinatal Center, Institute of Physiology and Neuroscience, Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Rebecca Lim
- The Ritchie Centre, Hudson Institute of Medical ResearchClayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University ClaytonClayton, VIC, Australia
| | - Claire Thornton
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' HospitalLondon, United Kingdom
| | - Carina Mallard
- Perinatal Center, Institute of Physiology and Neuroscience, Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Henrik Hagberg
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' HospitalLondon, United Kingdom.,Perinatal Center, Department of Clinical Sciences, Sahlgrenska Academy, Gothenburg UniversityGothenburg, Sweden
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23
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Fedorovich SV, Waseem TV, Puchkova LV. Biogenetic and morphofunctional heterogeneity of mitochondria: the case of synaptic mitochondria. Rev Neurosci 2017; 28:363-373. [DOI: 10.1515/revneuro-2016-0077] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/29/2016] [Indexed: 12/26/2022]
Abstract
AbstractThe mitochondria of different cells are different in their morphological and biochemical properties. These organelles generate free radicals during activity, leading inevitably to mitochondrial DNA damage. It is not clear how this problem is addressed in long-lived cells, such as neurons. We propose the hypothesis that mitochondria within the same cell also differ in lifespan and ability to divide. According to our suggestion, cells have a pool of ‘stem’ mitochondria with low metabolic activity and a pool of ‘differentiated’ mitochondria with significantly shorter lifespans and high metabolic activity. We consider synaptic mitochondria as a possible example of ‘differentiated’ mitochondria. They are significantly smaller than mitochondria from the cell body, and they are different in key enzyme activity levels, proteome, and lipidome. Synaptic mitochondria are more sensitive to different damaging factors. It has been established that neurons have a sorting mechanism that sends mitochondria with high membrane potential to presynaptic endings. This review describes the properties of synaptic mitochondria and their role in the regulation of synaptic transmission.
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Affiliation(s)
- Sergei V. Fedorovich
- Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, Minsk 220072, Belarus
| | - Tatyana V. Waseem
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Ludmila V. Puchkova
- Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya str., 29, St. Petersburg 195251, Russia
- ITMO University, Kronverksky av., 49, St.Petersburg 197101, Russia
- Institute of Experimental Medicine, Pavlova str., 12, St.Petersburg 197376, Russia
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24
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Grings M, Moura AP, Parmeggiani B, Pletsch JT, Cardoso GMF, August PM, Matté C, Wyse ATS, Wajner M, Leipnitz G. Bezafibrate prevents mitochondrial dysfunction, antioxidant system disturbance, glial reactivity and neuronal damage induced by sulfite administration in striatum of rats: Implications for a possible therapeutic strategy for sulfite oxidase deficiency. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2135-2148. [PMID: 28529047 DOI: 10.1016/j.bbadis.2017.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/30/2017] [Accepted: 05/17/2017] [Indexed: 12/13/2022]
Abstract
Sulfite accumulates in tissues of patients affected by sulfite oxidase (SO) deficiency, a neurometabolic disease characterized by seizures and progressive encephalopathy, often resulting in early death. We investigated the effects of sulfite on mitochondrial function, antioxidant system, glial reactivity and neuronal damage in rat striatum, as well as the potential protective effects of bezafibrate on sulfite-induced toxicity. Thirty-day-old rats were intrastriatally administered with sulfite (2μmol) or NaCl (2μmol; control) and euthanized 30min after injection for evaluation of biochemical parameters and western blotting, or 7days after injection for analysis of glial reactivity and neuronal damage. Treatment with bezafibrate (30 or 100mg/kg/day) was performed by gavage during 7days before (pre-treatment) or after sulfite administration. Sulfite decreased creatine kinase and citrate synthase activities, mitochondrial mass, and PGC-1α nuclear content whereas bezafibrate pre-treatment prevented these alterations. Sulfite also diminished cytochrome c oxidase (COX) IV-1 content, glutathione levels and the activities of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH). On the other hand, catalase activity was increased by sulfite. Bezafibrate pre-treatment prevented the reduction of GPx, GR, GST and G6PDH activities. Finally, sulfite induced glial reactivity and neuronal damage, which were prevented by bezafibrate when administered before or after sulfite administration. Our findings provide strong evidence that sulfite induces neurotoxicity that leads to glial reactivity and neuronal damage. Since bezafibrate exerts neuroprotective effects against sulfite toxicity, it may be an attractive agent for the development of novel therapeutic strategies for SO-deficient patients.
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Affiliation(s)
- Mateus Grings
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Alana Pimentel Moura
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Belisa Parmeggiani
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Julia Tauana Pletsch
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Gabriela Miranda Fernandez Cardoso
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Pauline Maciel August
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Cristiane Matté
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Angela T S Wyse
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil
| | - Moacir Wajner
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil; Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350, CEP 90035-903 Porto Alegre, RS, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003 Porto Alegre, RS, Brazil.
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25
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Tsuyama T, Tsubouchi A, Usui T, Imamura H, Uemura T. Mitochondrial dysfunction induces dendritic loss via eIF2α phosphorylation. J Cell Biol 2017; 216:815-834. [PMID: 28209644 PMCID: PMC5346966 DOI: 10.1083/jcb.201604065] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 11/30/2016] [Accepted: 01/19/2017] [Indexed: 12/25/2022] Open
Abstract
Mitochondrial dysfunction is associated with neuropathological events, but how it mediates loss of specific neuronal subtypes is unclear. Tsuyama et al. show that mitochondrial dysfunction triggers selective dendritic loss in class IV arborization neurons in a manner dependent on eIF2α phosphorylation and translation inhibition. Mitochondria are key contributors to the etiology of diseases associated with neuromuscular defects or neurodegeneration. How changes in cellular metabolism specifically impact neuronal intracellular processes and cause neuropathological events is still unclear. We here dissect the molecular mechanism by which mitochondrial dysfunction induced by Prel aberrant function mediates selective dendritic loss in Drosophila melanogaster class IV dendritic arborization neurons. Using in vivo ATP imaging, we found that neuronal cellular ATP levels during development are not correlated with the progression of dendritic loss. We searched for mitochondrial stress signaling pathways that induce dendritic loss and found that mitochondrial dysfunction is associated with increased eIF2α phosphorylation, which is sufficient to induce dendritic pathology in class IV arborization neurons. We also observed that eIF2α phosphorylation mediates dendritic loss when mitochondrial dysfunction results from other genetic perturbations. Furthermore, mitochondrial dysfunction induces translation repression in class IV neurons in an eIF2α phosphorylation-dependent manner, suggesting that differential translation attenuation among neuron subtypes is a determinant of preferential vulnerability.
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Affiliation(s)
- Taiichi Tsuyama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Asako Tsubouchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Tadao Usui
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Hiromi Imamura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Tadashi Uemura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
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26
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Cherubini M, Ginés S. Mitochondrial fragmentation in neuronal degeneration: Toward an understanding of HD striatal susceptibility. Biochem Biophys Res Commun 2017; 483:1063-1068. [DOI: 10.1016/j.bbrc.2016.08.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/25/2016] [Accepted: 08/07/2016] [Indexed: 12/31/2022]
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27
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Kannurpatti SS. Mitochondrial calcium homeostasis: Implications for neurovascular and neurometabolic coupling. J Cereb Blood Flow Metab 2017; 37:381-395. [PMID: 27879386 PMCID: PMC5381466 DOI: 10.1177/0271678x16680637] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mitochondrial function is critical to maintain high rates of oxidative metabolism supporting energy demands of both spontaneous and evoked neuronal activity in the brain. Mitochondria not only regulate energy metabolism, but also influence neuronal signaling. Regulation of "energy metabolism" and "neuronal signaling" (i.e. neurometabolic coupling), which are coupled rather than independent can be understood through mitochondria's integrative functions of calcium ion (Ca2+) uptake and cycling. While mitochondrial Ca2+ do not affect hemodynamics directly, neuronal activity changes are mechanistically linked to functional hyperemic responses (i.e. neurovascular coupling). Early in vitro studies lay the foundation of mitochondrial Ca2+ homeostasis and its functional roles within cells. However, recent in vivo approaches indicate mitochondrial Ca2+ homeostasis as maintained by the role of mitochondrial Ca2+ uniporter (mCU) influences system-level brain activity as measured by a variety of techniques. Based on earlier evidence of subcellular cytoplasmic Ca2+ microdomains and cellular bioenergetic states, a mechanistic model of Ca2+ mobilization is presented to understand systems-level neurovascular and neurometabolic coupling. This integrated view from molecular and cellular to the systems level, where mCU plays a major role in mitochondrial and cellular Ca2+ homeostasis, may explain the wide range of activation-induced coupling across neuronal activity, hemodynamic, and metabolic responses.
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28
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Grings M, Moura AP, Parmeggiani B, Motta MM, Boldrini RM, August PM, Matté C, Wyse ATS, Wajner M, Leipnitz G. Higher susceptibility of cerebral cortex and striatum to sulfite neurotoxicity in sulfite oxidase-deficient rats. Biochim Biophys Acta Mol Basis Dis 2016; 1862:2063-2074. [PMID: 27523630 DOI: 10.1016/j.bbadis.2016.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 07/27/2016] [Accepted: 08/09/2016] [Indexed: 12/22/2022]
Abstract
Patients affected by sulfite oxidase (SO) deficiency present severe seizures early in infancy and progressive neurological damage, as well as tissue accumulation of sulfite, thiosulfate and S-sulfocysteine. Since the pathomechanisms involved in the neuropathology of SO deficiency are still poorly established, we evaluated the effects of sulfite on redox homeostasis and bioenergetics in cerebral cortex, striatum, cerebellum and hippocampus of rats with chemically induced SO deficiency. The deficiency was induced in 21-day-old rats by adding 200ppm of tungsten, a molybdenum competitor, in their drinking water for 9weeks. Sulfite (70mg/kg/day) was also administered through the drinking water from the third week of tungsten supplementation until the end of the treatment. Sulfite decreased reduced glutathione concentrations and the activities of glutathione reductase and glutathione S-transferase (GST) in cerebral cortex and of GST in cerebellum of SO-deficient rats. Moreover, sulfite increased the activities of complexes II and II-III in striatum and of complex II in hippocampus, but reduced the activity of complex IV in striatum of SO-deficient rats. Sulfite also decreased the mitochondrial membrane potential in cerebral cortex and striatum, whereas it had no effect on mitochondrial mass in any encephalic tissue evaluated. Finally, sulfite inhibited the activities of malate and glutamate dehydrogenase in cerebral cortex of SO-deficient rats. Taken together, our findings indicate that cerebral cortex and striatum are more vulnerable to sulfite-induced toxicity than cerebellum and hippocampus. It is presumed that these pathomechanisms may contribute to the pathophysiology of neurological damage found in patients affected by SO deficiency.
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Affiliation(s)
- Mateus Grings
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Alana Pimentel Moura
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Belisa Parmeggiani
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marcela Moreira Motta
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rafael Mello Boldrini
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Pauline Maciel August
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Cristiane Matté
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003, Porto Alegre, RS, Brazil
| | - Angela T S Wyse
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003, Porto Alegre, RS, Brazil
| | - Moacir Wajner
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003, Porto Alegre, RS, Brazil; Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350, CEP 90035-903, Porto Alegre, RS, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, CEP 90035-003, Porto Alegre, RS, Brazil.
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29
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Kuter K, Kratochwil M, Berghauzen-Maciejewska K, Głowacka U, Sugawa MD, Ossowska K, Dencher NA. Adaptation within mitochondrial oxidative phosphorylation supercomplexes and membrane viscosity during degeneration of dopaminergic neurons in an animal model of early Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2016; 1862:741-753. [PMID: 26844379 DOI: 10.1016/j.bbadis.2016.01.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/27/2016] [Accepted: 01/29/2016] [Indexed: 01/02/2023]
Abstract
In Parkinson's disease (PD) motor symptoms are not observed until loss of 70% of dopaminergic neurons in substantia nigra (SN), preventing early diagnosis. Mitochondrial dysfunction was indicated in neuropathological process already at early PD stages. Aging and oxidative stress, the main factors in PD pathogenesis, cause membrane stiffening, which could influence functioning of membrane-bound oxidative phosphorylation (OxPhos) complexes (Cxs) in mitochondria. In 6-OHDA rat model, medium-sized dopaminergic lesion was used to study mitochondrial membrane viscosity and changes at the level of OxPhos Cxs and their higher assembled states-supercomplexes (SCxs), during the early degeneration processes and after it. We observed loss of dopaminergic phenotype in SN and decreased dopamine level in striatum (STR) before actual death of neurons in SN. Behavioural deficits induced by lesion were reversed despite progressing neurodegeneration. Along with degeneration process in STR, mitochondrial Cx I performance and amount decreased in almost all forms of SCxs. Also, progressing decrease of Cx IV performance in SCxs (I1III2IV3-1, I1IV2-1) in STR was observed during degeneration. In SN, SCxs containing Cx I increased protein amount and a shifted individual Cx I1 into superassembled states. Importantly, mitochondrial membrane viscosity changed in parallel with altered SCxs performance. We show for the first time changes at the level of mitochondrial membrane viscosity influencing SCxs function after dopaminergic system degeneration. It implicates that altered mitochondrial membrane viscosity could play an important role in regulation of mitochondria functioning and pathomechanisms of PD. The data obtained are also discussed in relation to compensatory processes observed.
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Affiliation(s)
- Katarzyna Kuter
- Department of Neuropsychopharmacology, Polish Academy of Sciences, Smętna St. 12, 31-343 Kraków, Poland.
| | - Manuela Kratochwil
- Physical Biochemistry, Department of Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany
| | | | - Urszula Głowacka
- Department of Neuropsychopharmacology, Polish Academy of Sciences, Smętna St. 12, 31-343 Kraków, Poland
| | - Michiru D Sugawa
- Physical Biochemistry, Department of Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany; Clinical Neurobiology, Charité-Universitätsmedizin, D-12203 Berlin, Germany
| | - Krystyna Ossowska
- Department of Neuropsychopharmacology, Polish Academy of Sciences, Smętna St. 12, 31-343 Kraków, Poland
| | - Norbert A Dencher
- Physical Biochemistry, Department of Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany
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30
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Burtscher J, Zangrandi L, Schwarzer C, Gnaiger E. Differences in mitochondrial function in homogenated samples from healthy and epileptic specific brain tissues revealed by high-resolution respirometry. Mitochondrion 2015; 25:104-12. [PMID: 26516105 DOI: 10.1016/j.mito.2015.10.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 10/22/2022]
Abstract
Mitochondrial dysfunction and oxidative stress are strongly implicated in neurodegenerative diseases and epilepsy. Strikingly, neurodegenerative diseases show regional specificity in vulnerability and follow distinct patterns of neuronal loss. A challenge is to understand, why mitochondria fail in particular brain regions under specific pathological conditions. A potential explanation could be provided by regional or cellular specificity of mitochondrial function. We applied high-resolution respirometry to analyze the integrated Complex I- and II (CI and CII)-linked respiration, the activity of Complex IV, and the combined CI&II-linked oxidative phosphorylation (OXPHOS)- and electron-transfer system (ETS)-capacity in microsamples obtained from distinct regions of the mouse brain. We compared different approaches to assess mitochondrial density and suggest flux control ratios as a valid method to normalize respiration to mitochondrial density. This approach revealed significant differences of CI- and CII-linked OXPHOS capacity and coupling control between motor cortex, striatum, hippocampus and pons of naïve mice. CI-linked respiration was highest in motor cortex, while CII-linked respiration predominated in the striatum. To investigate if this method could also determine differences in normal and disease states within the same brain region, we compared hippocampal homogenates in a chronic epilepsy model. Three weeks after stereotaxic injection of kainate, there was a down-regulation of CI- and upregulation of CII-linked respiration in the resulting epileptic ipsilateral hippocampus compared to the contralateral one. In summary, respirometric OXPHOS analysis provides a very sensitive diagnostic approach using small amounts of distinct brain tissues. In a single assay, information is obtained on numerous OXPHOS parameters as indicators of tissue-specific mitochondrial performance.
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Affiliation(s)
- Johannes Burtscher
- Dept. Pharmacology, Medical University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria
| | - Luca Zangrandi
- Dept. Pharmacology, Medical University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria
| | - Christoph Schwarzer
- Dept. Pharmacology, Medical University Innsbruck, Peter-Mayr-Str. 1a, 6020 Innsbruck, Austria.
| | - Erich Gnaiger
- D. Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria; OROBOROS INSTRUMENTS, Schöpfstr. 18, 6020 Innsbruck, Austria.
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31
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Guedes-Dias P, Pinho BR, Soares TR, de Proença J, Duchen MR, Oliveira JMA. Mitochondrial dynamics and quality control in Huntington's disease. Neurobiol Dis 2015; 90:51-7. [PMID: 26388396 DOI: 10.1016/j.nbd.2015.09.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/11/2015] [Accepted: 09/16/2015] [Indexed: 12/21/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder caused by polyglutamine expansion mutations in the huntingtin protein. Despite its ubiquitous distribution, expression of mutant huntingtin (mHtt) is particularly detrimental to medium spiny neurons within the striatum. Mitochondrial dysfunction has been associated with HD pathogenesis. Here we review the current evidence for mHtt-induced abnormalities in mitochondrial dynamics and quality control, with a particular focus on brain and neuronal data pertaining to striatal vulnerability. We address mHtt effects on mitochondrial biogenesis, protein import, complex assembly, fission and fusion, mitochondrial transport, and on the degradation of damaged mitochondria via autophagy (mitophagy). For an integrated perspective on potentially converging pathogenic mechanisms, we also address impaired autophagosomal transport and abnormal mHtt proteostasis in HD.
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Affiliation(s)
- Pedro Guedes-Dias
- REQUIMTE/LAQV, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal; Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Tânia R Soares
- REQUIMTE/LAQV, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - João de Proença
- REQUIMTE/LAQV, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal.
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Herbst EAF, Holloway GP. Permeabilization of brain tissue in situ enables multiregion analysis of mitochondrial function in a single mouse brain. J Physiol 2015; 593:787-801. [PMID: 25529987 DOI: 10.1113/jphysiol.2014.285379] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/08/2014] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS Mitochondrial function in the brain is traditionally assessed through analysing respiration in isolated mitochondria, a technique that possesses significant tissue and time requirements while also disrupting the cooperative mitochondrial reticulum. We permeabilized brain tissue in situ to permit analysis of mitochondrial respiration with the native mitochondrial morphology intact, removing the need for isolation time and minimizing tissue requirements to ∼2 mg wet weight. The permeabilized brain technique was validated against the traditional method of isolated mitochondria and was then further applied to assess regional variation in the mouse brain with ischaemia-reperfusion injuries. A transgenic mouse model overexpressing catalase within mitochondria was applied to show the contribution of mitochondrial reactive oxygen species to ischaemia-reperfusion injuries in different brain regions. This technique enhances the accessibility of addressing physiological questions in small brain regions and in applying transgenic mouse models to assess mechanisms regulating mitochondrial function in health and disease. ABSTRACT Mitochondria function as the core energy providers in the brain and symptoms of neurodegenerative diseases are often attributed to their dysregulation. Assessing mitochondrial function is classically performed in isolated mitochondria; however, this process requires significant isolation time, demand for abundant tissue and disruption of the cooperative mitochondrial reticulum, all of which reduce reliability when attempting to assess in vivo mitochondrial bioenergetics. Here we introduce a method that advances the assessment of mitochondrial respiration in the brain by permeabilizing existing brain tissue to grant direct access to the mitochondrial reticulum in situ. The permeabilized brain preparation allows for instant analysis of mitochondrial function with unaltered mitochondrial morphology using significantly small sample sizes (∼2 mg), which permits the analysis of mitochondrial function in multiple subregions within a single mouse brain. Here this technique was applied to assess regional variation in brain mitochondrial function with acute ischaemia-reperfusion injuries and to determine the role of reactive oxygen species in exacerbating dysfunction through the application of a transgenic mouse model overexpressing catalase within mitochondria. Through creating accessibility to small regions for the investigation of mitochondrial function, the permeabilized brain preparation enhances the capacity for examining regional differences in mitochondrial regulation within the brain, as the majority of genetic models used for unique approaches exist in the mouse model.
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Affiliation(s)
- Eric A F Herbst
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Zhang W, Li K, Zhu X, Wu D, Shang W, Yuan X, Huang Z, Zheng M, Wang X, Yang D, Liu J, Cheng H. Subsarcolemmal mitochondrial flashes induced by hypochlorite stimulation in cardiac myocytes. Free Radic Res 2014; 48:1085-94. [PMID: 24912881 DOI: 10.3109/10715762.2014.932114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mitochondrial superoxide flash (mitoflash) reflects quantal and bursting superoxide production and concurrent membrane depolarization triggered by transient mitochondrial permeability transition in many types of cells, at the level of single mitochondria. Here we investigate reactive oxygen species (ROS)-mediated modulation of mitoflash activity in cardiac myocytes and report a surprising finding that hypochlorite ions potently and preferentially triggered mitoflashes in the subsarcolemmal mitochondria (SSM), whereas hydrogen peroxide (H2O2) elicited mitoflash activity uniformly among SSM and interfibrillar mitochondria (IFM). The striking SSM mitoflash response to hypochlorite stimulation remained intact in cardiac myocytes from NOX2-deficient mice, excluding local NOX2-mediated ROS as the major player. Furthermore, it occurred concomitantly with SSM Ca(2+) accumulation and local Ca(2+) and CaMKII signaling played an important modulatory role by altering frequency and unitary properties of SSM mitoflashes. These findings underscore the functional heterogeneity of SSM and IFM and the oxidant-specific responsiveness of mitochondria to ROS, and may bear important ramifications in devising therapeutic strategies for the treatment of oxidative stress-related heart diseases.
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Affiliation(s)
- W Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University , Beijing , China
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Amadoro G, Corsetti V, Florenzano F, Atlante A, Bobba A, Nicolin V, Nori SL, Calissano P. Morphological and bioenergetic demands underlying the mitophagy in post-mitotic neurons: the pink-parkin pathway. Front Aging Neurosci 2014; 6:18. [PMID: 24600391 PMCID: PMC3927396 DOI: 10.3389/fnagi.2014.00018] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/27/2014] [Indexed: 01/12/2023] Open
Abstract
Evidence suggests a striking causal relationship between changes in quality control of neuronal mitochondria and numerous devastating human neurodegenerative diseases, including Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. Contrary to replicating mammalian cells with a metabolism essentially glycolytic, post-mitotic neurons are distinctive owing to (i) their exclusive energetic dependence from mitochondrial metabolism and (ii) their polarized shape, which entails compartmentalized and distinct energetic needs. Here, we review the recent findings on mitochondrial dynamics and mitophagy in differentiated neurons focusing on how the exceptional characteristics of neuronal populations in their morphology and bioenergetics needs make them quite different to other cells in controlling the intracellular turnover of these organelles.
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Affiliation(s)
- Giuseppina Amadoro
- Institute of Translational Pharmacology - National Research Council Rome, Italy ; European Brain Research Institute Rome, Italy
| | - Veronica Corsetti
- Institute of Translational Pharmacology - National Research Council Rome, Italy
| | | | - Anna Atlante
- Institute of Biomembrane and Bioenergetics - National Research Council Bari, Italy
| | - Antonella Bobba
- Institute of Biomembrane and Bioenergetics - National Research Council Bari, Italy
| | - Vanessa Nicolin
- Clinical Department of Medical, Surgical and Health Science, University of Trieste Trieste, Italy
| | - Stefania L Nori
- Department of Medicine and Surgery, University of Salerno Baronissi, Italy
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35
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Robinson PA. Understanding the molecular basis of Parkinson’s disease, identification of biomarkers and routes to therapy. Expert Rev Proteomics 2014; 7:565-78. [DOI: 10.1586/epr.10.40] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bereiter-Hahn J. Do we age because we have mitochondria? PROTOPLASMA 2014; 251:3-23. [PMID: 23794102 DOI: 10.1007/s00709-013-0515-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
The process of aging remains a great riddle. Production of reactive oxygen species (ROS) by mitochondria is an inevitable by-product of respiration, which has led to a hypothesis proposing the oxidative impairment of mitochondrial components (e.g., mtDNA, proteins, lipids) that initiates a vicious cycle of dysfunctional respiratory complexes producing more ROS, which again impairs function. This does not exclude other processes acting in parallel or targets for ROS action in other organelles than mitochondria. Given that aging is defined as the process leading to death, the role of mitochondria-based impairments in those organ systems responsible for human death (e.g., the cardiovascular system, cerebral dysfunction, and cancer) is described within the context of "garbage" accumulation and increasing insulin resistance, type 2 diabetes, and glycation of proteins. Mitochondrial mass, fusion, and fission are important factors in coping with impaired function. Both biogenesis of mitochondria and their degradation are important regulatory mechanisms stimulated by physical exercise and contribute to healthy aging. The hypothesis of mitochondria-related aging should be revised to account for the limitations of the degradative capacity of the lysosomal system. The processes involved in mitochondria-based impairments are very similar across a large range of organisms. Therefore, studies on model organisms from yeast, fungi, nematodes, flies to vertebrates, and from cells to organisms also add considerably to the understanding of human aging.
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Affiliation(s)
- Jürgen Bereiter-Hahn
- Institut für Zellbiologie und Neurowissenschaften, Goethe Universität Frankfurt am Main, Max-von-Lauestrasse 13, 60438, Frankfurt am Main, Germany,
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37
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Buck KJ, Walter NAR, Denmark DL. Genetic variability of respiratory complex abundance, organization and activity in mouse brain. GENES BRAIN AND BEHAVIOR 2013; 13:135-43. [PMID: 24164700 DOI: 10.1111/gbb.12101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/22/2013] [Accepted: 10/24/2013] [Indexed: 12/14/2022]
Abstract
Mitochondrial dysfunction is implicated in the etiology and pathogenesis of numerous human disorders involving tissues with high energy demand. Murine models are widely used to elucidate genetic determinants of phenotypes relevant to human disease, with recent studies of C57BL/6J (B6), DBA/2J (D2) and B6xD2 populations implicating naturally occurring genetic variation in mitochondrial function/dysfunction. Using blue native polyacrylamide gel electrophoresis, immunoblots and in-gel activity analyses of complexes I, II, III, IV and V, our studies are the first to assess abundance, organization and catalytic activity of mitochondrial respiratory complexes and supercomplexes in mouse brain. Remarkable strain differences in supercomplex assembly and associated activity are evident, without differences in individual complexes I, II, III or IV. Supercomplexes I1 III2 IV2-3 exhibit robust complex III immunoreactivity and activities of complexes I and IV in D2, but with little detected in B6 for I1 III2 IV2 , and I1 III2 IV3 is not detected in B6. I1 III2 IV1 and I1 III2 are abundant and catalytically active in both strains, but significantly more so in B6. Furthermore, while supercomplex III2 IV1 is abundant in D2, none is detected in B6. In aggregate, these results indicate a shift toward more highly assembled supercomplexes in D2. Respiratory supercomplexes are thought to increase electron flow efficiency and individual complex stability, and to reduce electron leak and generation of reactive oxygen species. Our results provide a framework to begin assessing the role of respiratory complex suprastructure in genetic vulnerability and treatment for a wide variety of mitochondrial-related disorders.
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Affiliation(s)
- K J Buck
- Department of Behavioral Neuroscience, Veterans Affairs Medical Center and Oregon Health & Science University, Portland, OR, USA
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38
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González-Cabo P, Palau F. Mitochondrial pathophysiology in Friedreich's ataxia. J Neurochem 2013; 126 Suppl 1:53-64. [PMID: 23859341 DOI: 10.1111/jnc.12303] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/09/2013] [Accepted: 05/08/2013] [Indexed: 12/01/2022]
Abstract
Neurological examination indicates that Friedreich's ataxia corresponds to a mixed sensory and cerebellar ataxia, which affects the proprioceptive pathways. Neuropathology and pathophysiology of Friedreich's ataxia involves the peripheral sensory nerves, dorsal root ganglia, posterior columns, the spinocerebellar, and corticospinal tracts of the spinal cord, gracile and cuneate nuclei, dorsal nuclei of Clarke, and the dentate nucleus. Involvement of the myocardium and pancreatic islets of Langerhans indicates that it is also a systemic disease. The pathophysiology of the disease is the consequence of frataxin deficiency in the mitochondria and cells. Some of the biological consequences are currently recognized such as the effects on iron-sulfur cluster biogenesis or the oxidative status, but others deserve to be studied in depth. Among physiological aspects of mitochondria that have been associated with neurodegeneration and may be interesting to investigate in Friedreich's ataxia we can include mitochondrial dynamics and movement, communication with other organelles especially the endoplasmic reticulum, calcium homeostasis, apoptosis, and mitochondrial biogenesis and quality control. Changes in the mitochondrial physiology and transport in peripheral and central axons and mitochondrial metabolic functions such as bioenergetics and energy delivery in the synapses are also relevant functions to be considered. Thus, to understand the general pathophysiology of the disease and fundamental pathogenic mechanisms such as dying-back axonopathy, and determine molecular, cellular and tissue therapeutic targets, we need to discover the effect of frataxin depletion on mitochondrial properties and on specific cell susceptibility in the nervous system and other affected organs.
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Affiliation(s)
- Pilar González-Cabo
- Program in Rare and Genetic Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain
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39
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Germain M, Nguyen AP, Khacho M, Patten DA, Screaton RA, Park DS, Slack RS. LKB1-regulated adaptive mechanisms are essential for neuronal survival following mitochondrial dysfunction. Hum Mol Genet 2012. [DOI: 10.1093/hmg/dds500] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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40
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Cardoso S, Santos RX, Correia SC, Carvalho C, Santos MS, Baldeiras I, Oliveira CR, Moreira PI. Insulin-induced recurrent hypoglycemia exacerbates diabetic brain mitochondrial dysfunction and oxidative imbalance. Neurobiol Dis 2012; 49:1-12. [PMID: 22940631 DOI: 10.1016/j.nbd.2012.08.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 07/21/2012] [Accepted: 08/16/2012] [Indexed: 12/17/2022] Open
Abstract
Intensive insulin therapy can prevent or slow the progression of long-term diabetes complications but, at the same time, it increases the risk for episodes of severe hypoglycemia. In our study, we used a protocol intended to mimic the levels of blood glucose that occur in type 1 diabetic patients under an intensive insulin therapy. Streptozotocin (STZ)-induced diabetic rats were treated subcutaneously with twice-daily insulin injections for 2weeks to induce hypoglycemic episodes. Brain cortical and hippocampal mitochondria were isolated and mitochondrial bioenergetics (respiratory chain and phosphorylation system) and oxidative status parameters (malondialdehyde (MDA) levels, mitochondrial aconitase activity and enzymatic and non-enzymatic antioxidant defenses) were analyzed. The protein levels of synaptophysin, a marker of synaptic integrity, and caspase 9 activity were also evaluated in cortical and hippocampal homogenates. Brain cortical mitochondria isolated from hyper- and recurrent hypoglycemic animals presented higher levels of MDA and α-tocopherol together with an increased glutathione disulfide reductase activity, lower manganese superoxide dismutase (MnSOD) activity and glutathione-to-glutathione disulfide (GSH/GSSG) ratio. No significant alterations were found in cortical mitochondrial respiratory chain and oxidative phosphorylation system. Hippocampal mitochondria from both experimental groups presented an impaired oxidative phosphorylation system characterized by a decreased mitochondrial energization potential and ATP levels and higher repolarization lag phase. In addition, higher MDA levels and decreased GSH/GSSG, α-tocopherol levels, and aconitase, glutathione peroxidase and MnSOD activities were observed in both groups of animals. Hippocampal mitochondria from recurrent hypoglycemic animals also showed an impairment of the respiratory chain characterized by a lower state 3 of respiration, respiratory control ratio and ADP/O index, and a higher state 4 of respiration. Additionally, a non-statistically significant decrease in synaptophysin protein levels was observed in cortical homogenates from recurrent hypoglycemic rats as well as in hippocampal homogenates from hyperglycemic and recurrent hypoglycemic rats. An increase in caspase 9 activity was also observed in hippocampal homogenates from hyperglycemic and recurrent hypoglycemic animals. Our results show that mitochondrial dysfunction induced by long-term hyperglycemic effects is exacerbated by recurrent hypoglycemia, which may compromise the function and integrity of brain cells.
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Affiliation(s)
- Susana Cardoso
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Renato X Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Sónia C Correia
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Cristina Carvalho
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Maria S Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Inês Baldeiras
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Laboratory of Neurochemistry, Coimbra University Hospital, Portugal; Neurology Department, Faculty of Medicine, University of Coimbra, Portugal
| | - Catarina R Oliveira
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Institute of Biochemistry, Faculty of Medicine, University of Coimbra, Portugal
| | - Paula I Moreira
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Institute of Physiology, Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal.
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Leong DW, Komen JC, Hewitt CA, Arnaud E, McKenzie M, Phipson B, Bahlo M, Laskowski A, Kinkel SA, Davey GM, Heath WR, Voss AK, Zahedi RP, Pitt JJ, Chrast R, Sickmann A, Ryan MT, Smyth GK, Thorburn DR, Scott HS. Proteomic and metabolomic analyses of mitochondrial complex I-deficient mouse model generated by spontaneous B2 short interspersed nuclear element (SINE) insertion into NADH dehydrogenase (ubiquinone) Fe-S protein 4 (Ndufs4) gene. J Biol Chem 2012; 287:20652-63. [PMID: 22535952 PMCID: PMC3370248 DOI: 10.1074/jbc.m111.327601] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 04/05/2012] [Indexed: 01/11/2023] Open
Abstract
Eukaryotic cells generate energy in the form of ATP, through a network of mitochondrial complexes and electron carriers known as the oxidative phosphorylation system. In mammals, mitochondrial complex I (CI) is the largest component of this system, comprising 45 different subunits encoded by mitochondrial and nuclear DNA. Humans diagnosed with mutations in the gene NDUFS4, encoding a nuclear DNA-encoded subunit of CI (NADH dehydrogenase ubiquinone Fe-S protein 4), typically suffer from Leigh syndrome, a neurodegenerative disease with onset in infancy or early childhood. Mitochondria from NDUFS4 patients usually lack detectable NDUFS4 protein and show a CI stability/assembly defect. Here, we describe a recessive mouse phenotype caused by the insertion of a transposable element into Ndufs4, identified by a novel combined linkage and expression analysis. Designated Ndufs4(fky), the mutation leads to aberrant transcript splicing and absence of NDUFS4 protein in all tissues tested of homozygous mice. Physical and behavioral symptoms displayed by Ndufs4(fky/fky) mice include temporary fur loss, growth retardation, unsteady gait, and abnormal body posture when suspended by the tail. Analysis of CI in Ndufs4(fky/fky) mice using blue native PAGE revealed the presence of a faster migrating crippled complex. This crippled CI was shown to lack subunits of the "N assembly module", which contains the NADH binding site, but contained two assembly factors not present in intact CI. Metabolomic analysis of the blood by tandem mass spectrometry showed increased hydroxyacylcarnitine species, implying that the CI defect leads to an imbalanced NADH/NAD(+) ratio that inhibits mitochondrial fatty acid β-oxidation.
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Affiliation(s)
| | - Jasper C. Komen
- the Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
| | | | - Estelle Arnaud
- the Département de Génétique Médicale, Université de Lausanne, 1005 Lausanne, Switzerland
| | - Matthew McKenzie
- the Centre for Reproduction and Development, Monash Institute of Medical Research, Clayton, Victoria 3168, Australia
| | - Belinda Phipson
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Melanie Bahlo
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Adrienne Laskowski
- the Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Sarah A. Kinkel
- From the Molecular Medicine Division
- Immunology Division, and
- the Department of Medical Biology and
| | | | | | - Anne K. Voss
- From the Molecular Medicine Division
- the Department of Medical Biology and
| | - René P. Zahedi
- the Leibniz-Institut für Analytische Wissenschaften e.V., 44227 Dortmund, Germany
| | - James J. Pitt
- VCGS Pathology, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Roman Chrast
- the Département de Génétique Médicale, Université de Lausanne, 1005 Lausanne, Switzerland
| | - Albert Sickmann
- the Leibniz-Institut für Analytische Wissenschaften e.V., 44227 Dortmund, Germany
- the Medizinisches Proteom Center, Ruhr-Universität-Bochum, 44780 Bochum, Germany
| | - Michael T. Ryan
- the Department of Biochemistry, La Trobe University, Bundoora, Victoria 3086, Australia, and
| | - Gordon K. Smyth
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- the Department of Medical Biology and
- Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - David R. Thorburn
- the Murdoch Childrens Research Institute, Royal Children's Hospital and Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Hamish S. Scott
- From the Molecular Medicine Division
- the Department of Medical Biology and
- the Department of Molecular Pathology, Centre for Cancer Biology, SA Pathology, Box 14 Rundle Mall Post Office, Adelaide, South Australia 5000, Australia, and
- the Schools of Medicine and Molecular and Biomedical Science, University of Adelaide, South Australia 5005, Australia
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42
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Court FA, Coleman MP. Mitochondria as a central sensor for axonal degenerative stimuli. Trends Neurosci 2012; 35:364-72. [PMID: 22578891 DOI: 10.1016/j.tins.2012.04.001] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 03/19/2012] [Accepted: 04/02/2012] [Indexed: 12/12/2022]
Abstract
Axonal degeneration is a major contributor to neuronal dysfunction in many neurological conditions and has additional roles in development. It can be triggered by divergent stimuli including mechanical, metabolic, infectious, toxic, hereditary and inflammatory stresses. Axonal mitochondria are an important convergence point as regulators of bioenergetic metabolism, reactive oxygen species (ROS), Ca²⁺ homeostasis and protease activation. The challenges likely to render axonal mitochondria more vulnerable than their cellular counterparts are reviewed, including axonal transport, replenishing nuclear-encoded proteins and maintenance of quality control, fusion and fission in locations remote from the cell body. The potential for mitochondria to act as a decision node in axon loss is considered, highlighting the need to understand the biology of axonal mitochondria and their contributions to degenerative mechanisms for novel therapeutic strategies.
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Affiliation(s)
- Felipe A Court
- Millennium Nucleus for Regenerative Biology, Faculty of Biology, Catholic University of Chile, Santiago 8331150, Chile.
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43
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Pan JW, Duckrow RB, Spencer DD, Avdievich NI, Hetherington HP. Selective homonuclear polarization transfer for spectroscopic imaging of GABA at 7T. Magn Reson Med 2012; 69:310-6. [PMID: 22505305 DOI: 10.1002/mrm.24283] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Accepted: 03/13/2012] [Indexed: 12/29/2022]
Abstract
We develop and implement a selective homonuclear polarization transfer method for the detection of 3.0 ppm C-4 GABA resonance by spectroscopic imaging in the human brain at 7T. This single shot method is demonstrated with simulations and phantoms, which achieves comparable efficiency of detection to that of J-difference editing. The macromolecule resonance that commonly co-edits with GABA is suppressed at 7T through use of a narrow band preacquisition suppression pulse. This technique is implemented in humans with an eight channel transceiver array and high degree B(0) shimming to measure supplementary motor area and thalamic GABA in controls (n = 8) and epilepsy patients (n = 8 total). We find that the GABA/N-acetyl aspartate ratio in the thalamus of control volunteers, well controlled and poorly controlled epilepsy patients are 0.053 ± 0.012 (n = 8), 0.090 ± 0.012 (n = 2), and 0.038 ± 0.009 (n = 6), respectively.
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Affiliation(s)
- J W Pan
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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Molecular mechanisms of neonatal brain injury. Neurol Res Int 2012; 2012:506320. [PMID: 22363841 PMCID: PMC3272851 DOI: 10.1155/2012/506320] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 10/11/2011] [Indexed: 12/12/2022] Open
Abstract
Fetal/neonatal brain injury is an important cause of neurological disability. Hypoxia-ischemia and excitotoxicity are considered important insults, and, in spite of their acute nature, brain injury develops over a protracted time period during the primary, secondary, and tertiary phases. The concept that most of the injury develops with a delay after the insult makes it possible to provide effective neuroprotective treatment after the insult. Indeed, hypothermia applied within 6 hours after birth in neonatal encephalopathy reduces neurological disability in clinical trials. In order to develop the next generation of treatment, we need to know more about the pathophysiological mechanism during the secondary and tertiary phases of injury. We review some of the critical molecular events related to mitochondrial dysfunction and apoptosis during the secondary phase and report some recent evidence that intervention may be feasible also days-weeks after the insult.
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Lores-Arnaiz S, Bustamante J. Age-related alterations in mitochondrial physiological parameters and nitric oxide production in synaptic and non-synaptic brain cortex mitochondria. Neuroscience 2011; 188:117-24. [PMID: 21600964 DOI: 10.1016/j.neuroscience.2011.04.060] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/26/2011] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
Brain aging has been associated with mitochondrial dysfunction and changes in nitric oxide levels. The aim of this study was to evaluate the susceptibility of synaptic and non-synaptic mitochondria to aging-dependent dysfunction. State 3 respiratory rate and respiratory control were 43% and 33% decreased, respectively in brain cortex synaptosomes from 14-month-old animals, as compared with synaptosomes from 3-month-old mice. Respiratory rates were not significantly affected by aging in non-synaptic mitochondrial fractions. Mitochondrial dysfunction was associated with increases of 84% and 38% in H₂O₂ production rates in brain cortex synaptosomes and non-synaptic mitochondria, respectively, from 14-month-old mice, as compared with young animals. Synaptic mitochondria seem to be more susceptible to calcium insult in 14-month-old mice, as compared with non-synaptic mitochondria, as measured by response of both types of fractions to calcium-induced depolarization. With aging, nitric oxide (NO) production was 44% and 27% decreased both in synaptosomal and non-synaptic mitochondrial fractions, respectively. The results of this study suggest that with aging, mitochondrial function at the nerve terminals would be more susceptible to suffer alterations by the constant calcium changes occurring as a consequence of synaptic activity. Non-synaptic mitochondria would be more resistant to age-related dysfunction and oxidative damage.
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Affiliation(s)
- S Lores-Arnaiz
- Laboratory of Free Radical Biology, School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina.
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Sauerbeck A, Pandya J, Singh I, Bittman K, Readnower R, Bing G, Sullivan P. Analysis of regional brain mitochondrial bioenergetics and susceptibility to mitochondrial inhibition utilizing a microplate based system. J Neurosci Methods 2011; 198:36-43. [PMID: 21402103 DOI: 10.1016/j.jneumeth.2011.03.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 03/04/2011] [Accepted: 03/04/2011] [Indexed: 12/20/2022]
Abstract
The analysis of mitochondrial bioenergetic function typically has required 50-100 μg of protein per sample and at least 15 min per run when utilizing a Clark-type oxygen electrode. In the present work we describe a method utilizing the Seahorse Biosciences XF24 Flux Analyzer for measuring mitochondrial oxygen consumption simultaneously from multiple samples and utilizing only 5 μg of protein per sample. Utilizing this method we have investigated whether regionally based differences exist in mitochondria isolated from the cortex, striatum, hippocampus, and cerebellum. Analysis of basal mitochondrial bioenergetics revealed that minimal differences exist between the cortex, striatum, and hippocampus. However, the cerebellum exhibited significantly slower basal rates of Complex I and Complex II dependent oxygen consumption (p<0.05). Mitochondrial inhibitors affected enzyme activity proportionally across all samples tested and only small differences existed in the effect of inhibitors on oxygen consumption. Investigation of the effect of rotenone administration on Complex I dependent oxygen consumption revealed that exposure to 10 pM rotenone led to a clear time dependent decrease in oxygen consumption beginning 12 min after administration (p<0.05). These studies show that the utilization of this microplate based method for analysis of mitochondrial bioenergetics is effective at quantifying oxygen consumption simultaneously from multiple samples. Additionally, these studies indicate that minimal regional differences exist in mitochondria isolated from the cortex, striatum, or hippocampus. Furthermore, utilization of the mitochondrial inhibitors suggests that previous work indicating regionally specific deficits following systemic mitochondrial toxin exposure may not be the result of differences in the individual mitochondria from the affected regions.
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Affiliation(s)
- Andrew Sauerbeck
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA
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Bibliography. Genetics. Current world literature. Curr Opin Pediatr 2010; 22:833-5. [PMID: 21610333 DOI: 10.1097/mop.0b013e32834179f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Harhay GP, Smith TP, Alexander LJ, Haudenschild CD, Keele JW, Matukumalli LK, Schroeder SG, Van Tassell CP, Gresham CR, Bridges SM, Burgess SC, Sonstegard TS. An atlas of bovine gene expression reveals novel distinctive tissue characteristics and evidence for improving genome annotation. Genome Biol 2010; 11:R102. [PMID: 20961407 PMCID: PMC3218658 DOI: 10.1186/gb-2010-11-10-r102] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 07/22/2010] [Accepted: 10/20/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A comprehensive transcriptome survey, or gene atlas, provides information essential for a complete understanding of the genomic biology of an organism. We present an atlas of RNA abundance for 92 adult, juvenile and fetal cattle tissues and three cattle cell lines. RESULTS The Bovine Gene Atlas was generated from 7.2 million unique digital gene expression tag sequences (300.2 million total raw tag sequences), from which 1.59 million unique tag sequences were identified that mapped to the draft bovine genome accounting for 85% of the total raw tag abundance. Filtering these tags yielded 87,764 unique tag sequences that unambiguously mapped to 16,517 annotated protein-coding loci in the draft genome accounting for 45% of the total raw tag abundance. Clustering of tissues based on tag abundance profiles generally confirmed ontology classification based on anatomy. There were 5,429 constitutively expressed loci and 3,445 constitutively expressed unique tag sequences mapping outside annotated gene boundaries that represent a resource for enhancing current gene models. Physical measures such as inferred transcript length or antisense tag abundance identified tissues with atypical transcriptional tag profiles. We report for the first time the tissue-specific variation in the proportion of mitochondrial transcriptional tag abundance. CONCLUSIONS The Bovine Gene Atlas is the deepest and broadest transcriptome survey of any livestock genome to date. Commonalities and variation in sense and antisense transcript tag profiles identified in different tissues facilitate the examination of the relationship between gene expression, tissue, and gene function.
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Affiliation(s)
- Gregory P Harhay
- USDA-ARS US Meat Animal Research Center, State Spur 18 D, Clay Center, NE 68901, USA.
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Vos M, Lauwers E, Verstreken P. Synaptic mitochondria in synaptic transmission and organization of vesicle pools in health and disease. Front Synaptic Neurosci 2010; 2:139. [PMID: 21423525 PMCID: PMC3059669 DOI: 10.3389/fnsyn.2010.00139] [Citation(s) in RCA: 177] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 08/09/2010] [Indexed: 12/21/2022] Open
Abstract
Cell types rich in mitochondria, including neurons, display a high energy demand and a need for calcium buffering. The importance of mitochondria for proper neuronal function is stressed by the occurrence of neurological defects in patients suffering from a great variety of diseases caused by mutations in mitochondrial genes. Genetic and pharmacological evidence also reveal a role of these organelles in various aspects of neuronal physiology and in the pathogenesis of neurodegenerative disorders. Yet the mechanisms by which mitochondria can affect neurotransmission largely remain to be elucidated. In this review we focus on experimental data that suggest a critical function of synaptic mitochondria in the function and organization of synaptic vesicle pools, and in neurotransmitter release during intense neuronal activity. We discuss how calcium handling, ATP production and other mitochondrial mechanisms may influence synaptic vesicle pool organization and synaptic function. Given the link between synaptic mitochondrial function and neuronal communication, efforts toward better understanding mitochondrial biology may lead to novel therapeutic approaches of neurological disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and psychiatric disorders that are at least in part caused by mitochondrial deficits.
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Affiliation(s)
- Melissa Vos
- Department of Molecular and Developmental Genetics VIB, Leuven, Belgium
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Presynaptic mitochondria in functionally different motor neurons exhibit similar affinities for Ca2+ but exert little influence as Ca2+ buffers at nerve firing rates in situ. J Neurosci 2010; 30:1869-81. [PMID: 20130196 DOI: 10.1523/jneurosci.4701-09.2010] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mitochondria accumulate within nerve terminals and support synaptic function, most notably through ATP production. They can also sequester Ca(2+) during nerve stimulation, but it is unknown whether this limits presynaptic Ca(2+) levels at physiological nerve firing rates. Similarly, it is unclear whether mitochondrial Ca(2+) sequestration differs between functionally different nerve terminals. We addressed these questions using a combination of synthetic and genetically encoded Ca(2+) indicators to examine cytosolic and mitochondrial Ca(2+) levels in presynaptic terminals of tonic (MN13-Ib) and phasic (MNSNb/d-Is) motor neurons in Drosophila, which, as we determined, fire during fictive locomotion at approximately 42 Hz and approximately 8 Hz, respectively. Mitochondrial Ca(2+) sequestration starts in both terminals at approximately 250 nM, exhibits a similar Ca(2+)-uptake affinity (approximately 410 nM), and does not require Ca(2+) release from the endoplasmic reticulum. Nonetheless, mitochondrial Ca(2+) uptake in type Is terminals is more responsive to low-frequency nerve stimulation and this is due to higher cytosolic Ca(2+) levels. Since type Ib terminals have a higher mitochondrial density than Is terminals, it seemed possible that greater mitochondrial Ca(2+) sequestration may be responsible for the lower cytosolic Ca(2+) levels in Ib terminals. However, genetic and pharmacological manipulations of mitochondrial Ca(2+) uptake did not significantly alter nerve-stimulated elevations in cytosolic Ca(2+) levels in either terminal type within physiologically relevant rates of stimulation. Our findings indicate that presynaptic mitochondria have a similar affinity for Ca(2+) in functionally different nerve terminals, but do not limit cytosolic Ca(2+) levels within the range of motor neuron firing rates in situ.
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