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Flori L, Spezzini J, Calderone V, Testai L. Role of mitochondrial potassium channels in ageing. Mitochondrion 2024; 76:101857. [PMID: 38403095 DOI: 10.1016/j.mito.2024.101857] [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: 12/01/2023] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Ageing is described as an inevitable decline in body functions over time and an increase in susceptibility to age-related diseases. Therefore, the increase of life expectancy is also viewed as a condition in which many elderly will develop age-related diseases and disabilities, such as cardiovascular, metabolic, neurological and oncological ones. Currently, several recognized cellular hallmarks of senescence are taken in consideration to evaluate the level of biological ageing and are the topic to plan preventive/curative anti-ageing interventions, including genomic instability, epigenetic alterations, and mitochondrial dysfunction. In this scenario, alterations in the function/expression of mitochondrial ion channels have been found in ageing and associated to an impairment of calcium cycling and a reduced mitochondrial membrane potential. Although several ion channels have been described at mitochondrial level, undoubtedly the mitochondrial potassium (mitoK) channels are the most investigated. Therefore, this review summarized the evidence that sheds to light a correlation between age-related diseases and alteration of mitoK channels, focusing the attention of the main age-related diseases, i.e. cardiovascular, neurological and oncological ones.
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Affiliation(s)
- Lorenzo Flori
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Vincenzo Calderone
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Research Centre of Ageing Biology and Pathology, University of Pisa, Pisa, Italy
| | - Lara Testai
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Research Centre of Ageing Biology and Pathology, University of Pisa, Pisa, Italy.
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2
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Tureckova J, Hermanova Z, Marchetti V, Anderova M. Astrocytic TRPV4 Channels and Their Role in Brain Ischemia. Int J Mol Sci 2023; 24:ijms24087101. [PMID: 37108263 PMCID: PMC10138480 DOI: 10.3390/ijms24087101] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/06/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Transient receptor potential cation channels subfamily V member 4 (TRPV4) are non-selective cation channels expressed in different cell types of the central nervous system. These channels can be activated by diverse physical and chemical stimuli, including heat and mechanical stress. In astrocytes, they are involved in the modulation of neuronal excitability, control of blood flow, and brain edema formation. All these processes are significantly impaired in cerebral ischemia due to insufficient blood supply to the tissue, resulting in energy depletion, ionic disbalance, and excitotoxicity. The polymodal cation channel TRPV4, which mediates Ca2+ influx into the cell because of activation by various stimuli, is one of the potential therapeutic targets in the treatment of cerebral ischemia. However, its expression and function vary significantly between brain cell types, and therefore, the effect of its modulation in healthy tissue and pathology needs to be carefully studied and evaluated. In this review, we provide a summary of available information on TRPV4 channels and their expression in healthy and injured neural cells, with a particular focus on their role in ischemic brain injury.
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Affiliation(s)
- Jana Tureckova
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
| | - Zuzana Hermanova
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
- Second Faculty of Medicine, Charles University, 84 V Uvalu, 150 06 Prague, Czech Republic
| | - Valeria Marchetti
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
- Second Faculty of Medicine, Charles University, 84 V Uvalu, 150 06 Prague, Czech Republic
| | - Miroslava Anderova
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
- Second Faculty of Medicine, Charles University, 84 V Uvalu, 150 06 Prague, Czech Republic
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3
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Garcia SM, Hirschberg PR, Sarkar P, Siegel DM, Teegala SB, Vail GM, Routh VH. Insulin actions on hypothalamic glucose-sensing neurones. J Neuroendocrinol 2021; 33:e12937. [PMID: 33507001 PMCID: PMC10561189 DOI: 10.1111/jne.12937] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/13/2022]
Abstract
Subsequent to the discovery of insulin 100 years ago, great strides have been made in understanding its function, especially in the brain. It is now clear that insulin is a critical regulator of the neuronal circuitry controlling energy balance and glucose homeostasis. This review focuses on the effects of insulin and diabetes on the activity and glucose sensitivity of hypothalamic glucose-sensing neurones. We highlight the role of electrophysiological data in understanding how insulin regulates glucose-sensing neurones. A brief introduction describing the benefits and limitations of the major electrophysiological techniques used to investigate glucose-sensing neurones is provided. The mechanisms by which hypothalamic neurones sense glucose are discussed with an emphasis on those glucose-sensing neurones already shown to be modulated by insulin. Next, the literature pertaining to how insulin alters the activity and glucose sensitivity of these hypothalamic glucose-sensing neurones is described. In addition, the effects of impaired insulin signalling during diabetes and the ramifications of insulin-induced hypoglycaemia on hypothalamic glucose-sensing neurones are covered. To the extent that it is known, we present hypotheses concerning the mechanisms underlying the effects of these insulin-related pathologies. To conclude, electrophysiological data from the hippocampus are evaluated aiming to provide clues regarding how insulin might influence neuronal plasticity in glucose-sensing neurones. Although much has been accomplished subsequent to the discovery of insulin, the work described in our review suggests that the regulation of central glucose sensing by this hormone is both important and understudied.
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Affiliation(s)
- Stephanie M Garcia
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pamela R Hirschberg
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pallabi Sarkar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Dashiel M Siegel
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Suraj B Teegala
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Gwyndolin M Vail
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Vanessa H Routh
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
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4
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Zhao S, Wang M, Ma Z. Therapeutic potential of ATP-sensitive potassium channels in Parkinson's disease. Brain Res Bull 2021; 169:1-7. [PMID: 33434622 DOI: 10.1016/j.brainresbull.2021.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/19/2020] [Accepted: 01/04/2021] [Indexed: 11/19/2022]
Abstract
In the past decade, there was an increasing interest in the therapeutic potential targeting ATP-sensitive potassium (KATP) channels for an effective treatment of Parkinson's disease (PD). KATP channels are widely expressed in the central nervous system and were reported to mediate the degeneration and death of nigral dopamine neurons in the pathogenesis of PD. This review aims to address the pivotal roles of KATP channels played in the mechanisms underlying PD pathogenesis, and provide possible directions for further research from different perspectives, such as the vulnerability of dopamine neurons in the substantia nigra, neurotransmitter releasing, iron metabolism in the brain, α-synuclein secretion and mitochondrial dysfunction, which are off critical importance in the investigation of KATP channels-targeted precise therapeutic interventions for PD.
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Affiliation(s)
- Sha Zhao
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - MengZhen Wang
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - ZeGang Ma
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China; Institute of Brain Science and Disorders, Qingdao University, Qingdao, China.
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Morris G, Maes M, Berk M, Carvalho AF, Puri BK. Nutritional ketosis as an intervention to relieve astrogliosis: Possible therapeutic applications in the treatment of neurodegenerative and neuroprogressive disorders. Eur Psychiatry 2020; 63:e8. [PMID: 32093791 PMCID: PMC8057392 DOI: 10.1192/j.eurpsy.2019.13] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Nutritional ketosis, induced via either the classical ketogenic diet or the use of emulsified medium-chain triglycerides, is an established treatment for pharmaceutical resistant epilepsy in children and more recently in adults. In addition, the use of oral ketogenic compounds, fractionated coconut oil, very low carbohydrate intake, or ketone monoester supplementation has been reported to be potentially helpful in mild cognitive impairment, Parkinson’s disease, schizophrenia, bipolar disorder, and autistic spectrum disorder. In these and other neurodegenerative and neuroprogressive disorders, there are detrimental effects of oxidative stress, mitochondrial dysfunction, and neuroinflammation on neuronal function. However, they also adversely impact on neurone–glia interactions, disrupting the role of microglia and astrocytes in central nervous system (CNS) homeostasis. Astrocytes are the main site of CNS fatty acid oxidation; the resulting ketone bodies constitute an important source of oxidative fuel for neurones in an environment of glucose restriction. Importantly, the lactate shuttle between astrocytes and neurones is dependent on glycogenolysis and glycolysis, resulting from the fact that the astrocytic filopodia responsible for lactate release are too narrow to accommodate mitochondria. The entry into the CNS of ketone bodies and fatty acids, as a result of nutritional ketosis, has effects on the astrocytic glutamate–glutamine cycle, glutamate synthase activity, and on the function of vesicular glutamate transporters, EAAT, Na+, K+-ATPase, Kir4.1, aquaporin-4, Cx34 and KATP channels, as well as on astrogliosis. These mechanisms are detailed and it is suggested that they would tend to mitigate the changes seen in many neurodegenerative and neuroprogressive disorders. Hence, it is hypothesized that nutritional ketosis may have therapeutic applications in such disorders.
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Michael Maes
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia.,Department of Psychiatry, Chulalongkorn University, Faculty of Medicine, Bangkok, Thailand
| | - Michael Berk
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia.,Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia.,Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - André F Carvalho
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
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Dexmedetomidine attenuates the induction and reverses the progress of 6-hydroxydopamine- induced parkinsonism; involvement of KATP channels, alpha 2 adrenoceptors and anti-inflammatory mechanisms. Toxicol Appl Pharmacol 2019; 382:114743. [DOI: 10.1016/j.taap.2019.114743] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/20/2019] [Accepted: 08/30/2019] [Indexed: 01/18/2023]
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7
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León-Aparicio D, Salvador C, Aparicio-Trejo OE, Briones-Herrera A, Pedraza-Chaverri J, Vaca L, Sampieri A, Padilla-Flores T, López-González Z, León-Contreras JC, Hernández-Pando R, Escobar LI. Novel Potassium Channels in Kidney Mitochondria: The Hyperpolarization-Activated and Cyclic Nucleotide-Gated HCN Channels. Int J Mol Sci 2019; 20:ijms20204995. [PMID: 31601020 PMCID: PMC6834191 DOI: 10.3390/ijms20204995] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/05/2019] [Accepted: 10/05/2019] [Indexed: 12/18/2022] Open
Abstract
Hyperpolarization-activated cationic HCN channels comprise four members (HCN1–4) that control dendritic integration, synaptic transmission and action potential firing. In the kidney, HCN1, HCN2 and HCN3 are differentially expressed and contribute to the transport of sodium, potassium (K+) and ammonium into the nephrons. HCN3 is regulated by K+ diets in the kidney. In this work we performed a proteomic analysis of HCN3 expressed in human embryonic kidney cells (HEK293 cells). More than 50% of the interacting proteins belonged to mitochondria. Therefore, we explored the presence of HCN channels in kidney mitochondria. By immunoblotting and immunogold electron microscopy HCN3 protein expression was found in rat kidney mitochondria; it was also confirmed in human kidney. Patch-clamp recordings of renal mitochondria and mitochondria from HEK293 cells overexpressing HCN1, HCN2 and HCN3 channels, stained with MitoTracker Green FM, indicated that only HCN3 could produce inwardly K+ currents that were inhibited by ZD7288, a specific blocker of HCN channels. Furthermore, ZD7288 caused inhibition of the oxygen consumption coupled to ATP synthesis and hyperpolarization of the inner mitochondrial membrane. In conclusion, we show for the first time that pacemaker HCN channels contribute to K+ transport in mitochondria facilitating the activity of the respiratory chain and ATP synthesis by controlling the inner mitochondrial membrane potential.
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Affiliation(s)
- Daniel León-Aparicio
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Carolina Salvador
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Omar Emiliano Aparicio-Trejo
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Alfredo Briones-Herrera
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - José Pedraza-Chaverri
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Luis Vaca
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Alicia Sampieri
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Teresa Padilla-Flores
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Zinaeli López-González
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
| | - Juan C León-Contreras
- Departamento de Patología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City 14080, Mexico.
| | - Rogelio Hernández-Pando
- Departamento de Patología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City 14080, Mexico.
| | - Laura I Escobar
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico.
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8
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Ghincea CV, Ikeno Y, Aftab M, Reece TB. Spinal Cord Protection for Thoracic Aortic Surgery: Bench to Bedside. Semin Thorac Cardiovasc Surg 2019; 31:713-720. [DOI: 10.1053/j.semtcvs.2019.02.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 11/11/2022]
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9
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Szeto V, Chen NH, Sun HS, Feng ZP. The role of K ATP channels in cerebral ischemic stroke and diabetes. Acta Pharmacol Sin 2018; 39:683-694. [PMID: 29671418 PMCID: PMC5943906 DOI: 10.1038/aps.2018.10] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/19/2018] [Indexed: 12/18/2022] Open
Abstract
ATP-sensitive potassium (KATP) channels are ubiquitously expressed on the plasma membrane of cells in multiple organs, including the heart, pancreas and brain. KATP channels play important roles in controlling and regulating cellular functions in response to metabolic state, which are inhibited by ATP and activated by Mg-ADP, allowing the cell to couple cellular metabolic state (ATP/ADP ratio) to electrical activity of the cell membrane. KATP channels mediate insulin secretion in pancreatic islet beta cells, and controlling vascular tone. Under pathophysiological conditions, KATP channels play cytoprotective role in cardiac myocytes and neurons during ischemia and/or hypoxia. KATP channel is a hetero-octameric complex, consisting of four pore-forming Kir6.x and four regulatory sulfonylurea receptor SURx subunits. These subunits are differentially expressed in various cell types, thus determining the sensitivity of the cells to specific channel modifiers. Sulfonylurea class of antidiabetic drugs blocks KATP channels, which are neuroprotective in stroke, can be one of the high stoke risk factors for diabetic patients. In this review, we discussed the potential effects of KATP channel blockers when used under pathological conditions related to diabetics and cerebral ischemic stroke.
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Affiliation(s)
- Vivian Szeto
- Departments of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Nai-hong Chen
- Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Hong-shuo Sun
- Departments of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
- Surgery
- Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Zhong-ping Feng
- Departments of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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Pinto A, Bonucci A, Maggi E, Corsi M, Businaro R. Anti-Oxidant and Anti-Inflammatory Activity of Ketogenic Diet: New Perspectives for Neuroprotection in Alzheimer's Disease. Antioxidants (Basel) 2018; 7:E63. [PMID: 29710809 PMCID: PMC5981249 DOI: 10.3390/antiox7050063] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 12/11/2022] Open
Abstract
The ketogenic diet, originally developed for the treatment of epilepsy in non-responder children, is spreading to be used in the treatment of many diseases, including Alzheimer’s disease. The main activity of the ketogenic diet has been related to improved mitochondrial function and decreased oxidative stress. B-Hydroxybutyrate, the most studied ketone body, has been shown to reduce the production of reactive oxygen species (ROS), improving mitochondrial respiration: it stimulates the cellular endogenous antioxidant system with the activation of nuclear factor erythroid-derived 2-related factor 2 (Nrf2), it modulates the ratio between the oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD⁺/NADH) and it increases the efficiency of electron transport chain through the expression of uncoupling proteins. Furthermore, the ketogenic diet performs anti-inflammatory activity by inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) activation and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome as well as inhibiting histone deacetylases (HDACs), improving memory encoding. The underlying mechanisms and the perspectives for the treatment of Alzheimer’s disease are discussed.
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Affiliation(s)
- Alessandro Pinto
- Department of Experimental Medicine, Sapienza University of Rome, 00161 Roma, Italy.
| | - Alessio Bonucci
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, 04100 Latina, Italy.
| | - Elisa Maggi
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, 04100 Latina, Italy.
| | - Mariangela Corsi
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, 04100 Latina, Italy.
| | - Rita Businaro
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, 04100 Latina, Italy.
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Wu J, Li R, Li W, Ren M, Thangthaeng N, Sumien N, Liu R, Yang S, Simpkins JW, Forster MJ, Yan LJ. Administration of 5-methoxyindole-2-carboxylic acid that potentially targets mitochondrial dihydrolipoamide dehydrogenase confers cerebral preconditioning against ischemic stroke injury. Free Radic Biol Med 2017; 113:244-254. [PMID: 29017857 PMCID: PMC5699942 DOI: 10.1016/j.freeradbiomed.2017.10.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 09/09/2017] [Accepted: 10/06/2017] [Indexed: 02/06/2023]
Abstract
The objective of this study was to investigate a possible role of mitochondrial dihydrolipoamide dehydrogenase (DLDH) as a chemical preconditioning target for neuroprotection against ischemic injury. We used 5-methoxyindole-2-carboxylic acid (MICA), a reportedly reversible DLDH inhibitor, as the preconditioning agent and administered MICA to rats mainly via dietary intake. Upon completion of 4 week's MICA treatment, rats underwent 1h transient ischemia and 24h reperfusion followed by tissue collection. Our results show that MICA protected the brain against ischemic stroke injury as the infarction volume of the brain from the MICA-treated group was significantly smaller than that from the control group. Data were then collected without or with stroke surgery following MICA feeding. It was found that in the absence of stroke following MICA feeding, DLDH activity was lower in the MICA treated group than in the control group, and this decreased activity could be partly due to DLDH protein sulfenation. Moreover, DLDH inhibition by MICA was also found to upregulate the expression of NAD(P)H-ubiquinone oxidoreductase 1(NQO1) via the Nrf2 signaling pathway. In the presence of stroke following MICA feeding, decreased DLDH activity and increased Nrf2 signaling were also observed along with increased NQO1 activity, decreased oxidative stress, decreased cell death, and increased mitochondrial ATP output. We also found that MICA had a delayed preconditioning effect four weeks post MICA treatment. Our study indicates that administration of MICA confers chemical preconditioning and neuroprotection against ischemic stroke injury.
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Affiliation(s)
- Jinzi Wu
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Rongrong Li
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Wenjun Li
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ming Ren
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Nopporn Thangthaeng
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Nathalie Sumien
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ran Liu
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Shaohua Yang
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - James W Simpkins
- Department of Physiology and Pharmacology, Center for Basic and Translational Stroke Research, West Virginia University, 1 Medical Center Drive, Morgantown, WV 26506, USA
| | - Michael J Forster
- Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Liang-Jun Yan
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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Krabbendam IE, Honrath B, Culmsee C, Dolga AM. Mitochondrial Ca 2+-activated K + channels and their role in cell life and death pathways. Cell Calcium 2017; 69:101-111. [PMID: 28818302 DOI: 10.1016/j.ceca.2017.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022]
Abstract
Ca2+-activated K+ channels (KCa) are expressed at the plasma membrane and in cellular organelles. Expression of all KCa channel subtypes (BK, IK and SK) has been detected at the inner mitochondrial membrane of several cell types. Primary functions of these mitochondrial KCa channels include the regulation of mitochondrial ROS production, maintenance of the mitochondrial membrane potential and preservation of mitochondrial calcium homeostasis. These channels are therefore thought to contribute to cellular protection against oxidative stress through mitochondrial mechanisms of preconditioning. In this review, we summarize the current knowledge on mitochondrial KCa channels, and their role in mitochondrial function in relation to cell death and survival pathways. More specifically, we systematically discuss studies on the role of these mitochondrial KCa channels in pharmacological preconditioning, and according protective effects on ischemic insults to the brain and the heart.
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Affiliation(s)
- Inge E Krabbendam
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
| | - Birgit Honrath
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands; Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany.
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany.
| | - Amalia M Dolga
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
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Gao R, Yang T, Xu W. Enemies or weapons in hands: investigational anti-diabetic drug glibenclamide and cancer risk. Expert Opin Investig Drugs 2017; 26:853-864. [PMID: 28541801 DOI: 10.1080/13543784.2017.1333104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Epidemiological evidence suggests that diabetes is associated with elevated cancer risk through the actions of hyperglycemia, hyperinsulinemia and chronic inflammation. Metformin, a first-line medication for type 2 diabetes mellitus, arouses growing concerns on its anti-cancer effect. However, data regarding the effect of glibenclamide on tumor growth and cancer risk are less consistent, which may be a potential anti-cancer drug. Areas covered: In this review, we clarified probable underlying mechanisms in preclinical studies and reviewed epidemiological evidence on glibenclamide's cancer risk in clinical studies. Glibenclamide inhibited carcinogenesis through ATP-binding cassette protein super-family and ATP-sensitive potassium channels, while majority of clinical researches reported an increased or non-significant elevated cancer risk of glibenclamide users compared with metformin users. Other sulfonylureas and diarylsulfonylureas were also briefly introduced. Expert opinion: The inconsistency between the results of studies was probably ascribed to undiscovered mechanisms, confounding factors, inconsistent comparators and publication bias. Existing clinical trials were prone to be afflicted by time-related bias including immortal time bias, time-window bias, and time-lag bias. Glibenclimiade could be a promising and well-tolerated anti-neoplastic drug targeting ATP-binding cassette protein super-family and KATP channels, but its efficacy still needs to be proven in well-designed long-term randomized controlled clinical trials.
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Affiliation(s)
- Rui Gao
- a Department of Endocrinology , The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital , Nanjing , China
- b Department of Hematology , The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital , Nanjing , China
| | - Tao Yang
- a Department of Endocrinology , The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital , Nanjing , China
| | - Wei Xu
- b Department of Hematology , The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital , Nanjing , China
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Yoshida A, Hayashi H, Tanabe K, Fujita A. Segregation of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate into distinct microdomains on the endosome membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017. [PMID: 28648675 DOI: 10.1016/j.bbamem.2017.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Phosphatidylinositol 4-phosphate (PtdIns(4)P) is the immediate precursor of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), which is located on the cytoplasmic leaflet of the plasma membrane and has been reported to possess multiple cellular functions. Although PtdIns(4)P and PtdIns(4,5)P2 have been reported to localize to multiple intracellular compartments and to each function as regulatory molecules, their generation, regulation and functions in most intracellular compartments are not well-defined. To analyze PtdIns(4)P and PtdIns(4,5)P2 distributions, at a nanoscale, we employed an electron microscopy technique that specifically labels PtdIns(4)P and PtdIns(4,5)P2 on the freeze-fracture replica of intracellular biological membranes. This method minimizes the possibility of artificial perturbation, because molecules in the membrane are physically immobilized in situ. Using this technique, we found that PtdIns(4)P was localized to the cytoplasmic leaflet of Golgi apparatus and vesicular-shaped structures. The PtdIns(4,5)P2 labeling was observed in the cytoplasmic leaflet of the mitochondrial inner membrane and vesicular-shaped structures. Double labeling of PtdIns(4)P and PtdIns(4,5)P2 with endosome markers illustrated that PtdIns(4)P and PtdIns(4,5)P2 were mainly localized to the late endosome/lysosome and early endosome, respectively. PtdIns(4)P and PtdIns(4,5)P2 were colocalized in some endosomes, with the two phospholipids separated into distinct microdomains on the same endosomes. This is the first report showing, at a nanoscale, segregation of PtdIns(4)P- and PtdIns(4,5)P2-enriched microdomains in the endosome, of likely importance for endosome functionality.
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Affiliation(s)
- Akane Yoshida
- Field of Veterinary Pathobiology, Basic Veterinary Science, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Hiroki Hayashi
- Field of Veterinary Pathobiology, Basic Veterinary Science, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Kenji Tanabe
- Medical Research Institute, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Akikazu Fujita
- Field of Veterinary Pathobiology, Basic Veterinary Science, Department of Veterinary Medicine, Joint Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan.
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Zhang LC, Huang Z, Li PB, Nie HJ, Deng BN, Duan RF, Xiao ZH, Peng H, Feng H, Liu W. Diazoxide protects rat vascular endothelial cells against hypoxia and cold-induced damage. Exp Ther Med 2017; 13:3257-3266. [PMID: 28587398 PMCID: PMC5450562 DOI: 10.3892/etm.2017.4437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 01/26/2017] [Indexed: 02/07/2023] Open
Abstract
The present study aimed to examine the effects of hypoxia and cold on vascular endothelial cells (VECs), as well as the protective ability of novel VECs-protective drugs against these injuries. A rat model simulating exposure to hypoxia and cold at high altitude environments was established. Based on these animal experiments, rat aortic VECs were established as injury models and exposed to hypoxia and/or adrenaline (ADR) in vitro. The results revealed that hypoxia significantly altered the levels of nitric oxide and vascular endothelial growth factor, while the cold temperature significantly increased the release of ADR and noradrenaline. Exposure to hypoxia combined with cold temperature significantly affected all these indices. In vitro experiments demonstrated that hypoxia, ADR (which was used to simulate cold in the animal experiments) and the combination of the two factors resulted in damage to the VECs and endothelial dysfunction. In addition, the results also showed that diazoxide, a highly selective mitoKATP opener, protected VECs against these injuries. In conclusion, hypoxia and cold temperature induced endothelial cell dysfunction and endocrine disorders, respectively. Improving endothelial function using diazoxide may be an effective therapeutic strategy in patients with altitude-associated disorders. However, the potential for clinical application requires further study.
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Affiliation(s)
- Lian-Cheng Zhang
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Zhao Huang
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, P.R. China
| | - Pei-Bing Li
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Hong-Jing Nie
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Bing-Nan Deng
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Rui-Feng Duan
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Zhong-Hai Xiao
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Hui Peng
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
| | - Hong Feng
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin 300381, P.R. China
| | - Wei Liu
- Department of Environment and Pharmacy, Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, P.R. China
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Piri H, Haghdoost-Yazdi H, Fraidouni N, Dargahi T, Yaghoubidoust M, Azadmehr A. The Anti-Parkinsonism Effects of K ATP Channel Blockade in the 6-Hydroxydopamine-Induced Animal Model: The Role of Oxidative Stress. Basic Clin Neurosci 2017; 8:183-192. [PMID: 28781726 PMCID: PMC5535324 DOI: 10.18869/nirp.bcn.8.3.183] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION Studies suggest that ATP-sensitive potassium (KATP) channels are a potential pharmacotherapeutic target for neuroprotection in neurodegenerative diseases. The current study aimed at evaluating the effect of pretreatment with glibenclamide (Glib) and B vitamins supplement on the severity of behavioral symptoms in 6-hydroxydopamine (OHDA)-induced Parkinsonism. Also malondialdehyde (MDA) concentration was measured in the blood and brain suspensions to find probable neuroprotective mechanism of Glib. METHODS The 6-OHDA was injected into striatum of rats by stereotaxic surgery. Treatment with Glib and B vitamins was started before the surgery and continued up to 3 weeks after that. Development and severity of Parkinsonism were evaluated by conventional behavioral tests. MDA values were measured spectrophotometrically using thiobarbituric acid and MDA standard curve. RESULTS Pretreatments with Glib, at both doses of 1 and 5 mg/kg or B vitamins significantly ameliorated severity of the behavioral symptoms. Pretreatment with a combination of Glib and B vitamins was more effective than pretreatment with Glib or B vitamins alone. Also, pretreatment with B vitamins, Glib, or a combination of them reduced MDA concentration in the brain suspensions. Decrease in MDA concentration in the group of rats that received a combination of B vitamins and Glib was more prominent than that of the Glib groups. CONCLUSION As severity of the behavioral symptoms in the 6-OHDA-induced Parkinsonism reflects the degree of the lesion in Substantia Nigra (SN) dopaminergic neurons, it is suggested that Glib pretreatment has neuroprotective effect against 6-OHDA-induced neurotoxicity. The current study data also showed that this effect may be mediated by antioxidant effect of Glib.
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Affiliation(s)
- Hossein Piri
- Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Hashem Haghdoost-Yazdi
- Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Negin Fraidouni
- Student Research Committee, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Tahereh Dargahi
- Student Research Committee, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | | | - Abbas Azadmehr
- Department of Immunology, School of Medicine, Babol University of Medical Sciences, Babol, Iran
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Tolcos M, Petratos S, Hirst JJ, Wong F, Spencer SJ, Azhan A, Emery B, Walker DW. Blocked, delayed, or obstructed: What causes poor white matter development in intrauterine growth restricted infants? Prog Neurobiol 2017; 154:62-77. [PMID: 28392287 DOI: 10.1016/j.pneurobio.2017.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 03/17/2017] [Accepted: 03/29/2017] [Indexed: 12/22/2022]
Abstract
Poor white matter development in intrauterine growth restricted (IUGR) babies remains a major, untreated problem in neonatology. New therapies, guided by an understanding of the mechanisms that underlie normal and abnormal oligodendrocyte development and myelin formation, are required. Much of our knowledge of the mechanisms that underlie impaired myelination come from studies in adult demyelinating disease, preterm brain injury, or experimental models of hypoxia-ischemia. However, relatively less is known for IUGR which is surprising because IUGR is a leading cause of perinatal mortality and morbidity, second only to premature birth. IUGR is also a significant risk factor for the later development of cerebral palsy, and is a greater risk compared to some of the more traditionally researched antecedents - asphyxia and inflammation. Recent evidence suggests that the white matter injury and reduced myelination in the brains of some preterm babies is due to impaired maturation of oligodendrocytes thereby resulting in the reduced capacity to synthesize myelin. Therefore, it is not surprising that the hypomyelination observable in the central nervous system of IUGR infants has similarly lead to investigations identifying a delay or blockade in the progress of maturation of oligodendrocytes in these infants. This review will discuss current ideas thought to account for the poor myelination often present in the neonate's brain following IUGR, and discuss novel interventions that are promising as treatments that promote oligodendrocyte maturation, and thereby repair the myelination deficits that otherwise persist into infancy and childhood and lead to neurodevelopmental abnormalities.
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Affiliation(s)
- Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia.
| | - Steven Petratos
- Department of Medicine, Central Clinical School, Monash University, Prahran, Victoria, 3004, Australia
| | - Jonathan J Hirst
- School of Biomedical Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Flora Wong
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia; Monash Newborn and Monash University, Clayton, Victoria, 3168, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Aminath Azhan
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, 3168, Australia
| | - Ben Emery
- Oregon Health and Science University, Portland, OR, 97239-3098, USA
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, 3083, Australia
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Diazoxide Attenuates Postresuscitation Brain Injury in a Rat Model of Asphyxial Cardiac Arrest by Opening Mitochondrial ATP-Sensitive Potassium Channels. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1253842. [PMID: 27648441 PMCID: PMC5018309 DOI: 10.1155/2016/1253842] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 08/03/2016] [Indexed: 01/28/2023]
Abstract
Objective. We investigated whether and how diazoxide can attenuate brain injury after cardiopulmonary resuscitation (CPR) by selective opening of mitochondrial ATP-sensitive potassium (mitoKATP) channels. Methods. Adult male Sprague-Dawley rats with induced cerebral ischemia (n = 10 per group) received an intraperitoneal injection of 0.1% dimethyl sulfoxide (1 mL; vehicle group), diazoxide (10 mg/kg; DZ group), or diazoxide (10 mg/kg) plus 5-hydroxydecanoate (5 mg/kg; DZ + 5-HD group) 30 min after CPR. The control group (sham group, n = 5) underwent sham operation, without cardiac arrest. Mitochondrial respiratory control rate (RCR) was determined. Brain cell apoptosis was assessed using TUNEL staining. Expression of Bcl-2, Bax, and protein kinase C epsilon (PKCε) in the cerebral cortex was determined by Western blotting and immunohistochemistry. Results. The neurological deficit scores (NDS) in the vehicle group decreased significantly at 24 h and 48 h after CPR. Diazoxide significantly improved NDS and mitochondrial RCR after CPR at both time points; 5-HD cotreatment abolished these effects. Diazoxide decreased TUNEL-positive cells following CPR, upregulated Bcl-2 and PKCε, downregulated Bax, and increased the Bcl-2/Bax ratio; 5-HD cotreatment reversed these effects. Conclusions. Diazoxide attenuates postresuscitation brain injury, protects mitochondrial function, inhibits brain cell apoptosis, and activates the PKC pathway by opening mitoKATP channels.
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19
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Cunha RA. How does adenosine control neuronal dysfunction and neurodegeneration? J Neurochem 2016; 139:1019-1055. [PMID: 27365148 DOI: 10.1111/jnc.13724] [Citation(s) in RCA: 301] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/23/2016] [Accepted: 06/23/2016] [Indexed: 12/11/2022]
Abstract
The adenosine modulation system mostly operates through inhibitory A1 (A1 R) and facilitatory A2A receptors (A2A R) in the brain. The activity-dependent release of adenosine acts as a brake of excitatory transmission through A1 R, which are enriched in glutamatergic terminals. Adenosine sharpens salience of information encoding in neuronal circuits: high-frequency stimulation triggers ATP release in the 'activated' synapse, which is locally converted by ecto-nucleotidases into adenosine to selectively activate A2A R; A2A R switch off A1 R and CB1 receptors, bolster glutamate release and NMDA receptors to assist increasing synaptic plasticity in the 'activated' synapse; the parallel engagement of the astrocytic syncytium releases adenosine further inhibiting neighboring synapses, thus sharpening the encoded plastic change. Brain insults trigger a large outflow of adenosine and ATP, as a danger signal. A1 R are a hurdle for damage initiation, but they desensitize upon prolonged activation. However, if the insult is near-threshold and/or of short-duration, A1 R trigger preconditioning, which may limit the spread of damage. Brain insults also up-regulate A2A R, probably to bolster adaptive changes, but this heightens brain damage since A2A R blockade affords neuroprotection in models of epilepsy, depression, Alzheimer's, or Parkinson's disease. This initially involves a control of synaptotoxicity by neuronal A2A R, whereas astrocytic and microglia A2A R might control the spread of damage. The A2A R signaling mechanisms are largely unknown since A2A R are pleiotropic, coupling to different G proteins and non-canonical pathways to control the viability of glutamatergic synapses, neuroinflammation, mitochondria function, and cytoskeleton dynamics. Thus, simultaneously bolstering A1 R preconditioning and preventing excessive A2A R function might afford maximal neuroprotection. The main physiological role of the adenosine modulation system is to sharp the salience of information encoding through a combined action of adenosine A2A receptors (A2A R) in the synapse undergoing an alteration of synaptic efficiency with an increased inhibitory action of A1 R in all surrounding synapses. Brain insults trigger an up-regulation of A2A R in an attempt to bolster adaptive plasticity together with adenosine release and A1 R desensitization; this favors synaptotocity (increased A2A R) and decreases the hurdle to undergo degeneration (decreased A1 R). Maximal neuroprotection is expected to result from a combined A2A R blockade and increased A1 R activation. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
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Affiliation(s)
- Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,FMUC-Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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20
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Busija DW, Rutkai I, Dutta S, Katakam PV. Role of Mitochondria in Cerebral Vascular Function: Energy Production, Cellular Protection, and Regulation of Vascular Tone. Compr Physiol 2016; 6:1529-48. [PMID: 27347901 DOI: 10.1002/cphy.c150051] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mitochondria not only produce energy in the form of ATP to support the activities of cells comprising the neurovascular unit, but mitochondrial events, such as depolarization and/or ROS release, also initiate signaling events which protect the endothelium and neurons against lethal stresses via pre-/postconditioning as well as promote changes in cerebral vascular tone. Mitochondrial depolarization in vascular smooth muscle (VSM), via pharmacological activation of the ATP-dependent potassium channels on the inner mitochondrial membrane (mitoKATP channels), leads to vasorelaxation through generation of calcium sparks by the sarcoplasmic reticulum and subsequent downstream signaling mechanisms. Increased release of ROS by mitochondria has similar effects. Relaxation of VSM can also be indirectly achieved via actions of nitric oxide (NO) and other vasoactive agents produced by endothelium, perivascular and parenchymal nerves, and astroglia following mitochondrial activation. Additionally, NO production following mitochondrial activation is involved in neuronal preconditioning. Cerebral arteries from female rats have greater mitochondrial mass and respiration and enhanced cerebral arterial dilation to mitochondrial activators. Preexisting chronic conditions such as insulin resistance and/or diabetes impair mitoKATP channel relaxation of cerebral arteries and preconditioning. Surprisingly, mitoKATP channel function after transient ischemia appears to be retained in the endothelium of large cerebral arteries despite generalized cerebral vascular dysfunction. Thus, mitochondrial mechanisms may represent the elusive signaling link between metabolic rate and blood flow as well as mediators of vascular change according to physiological status. Mitochondrial mechanisms are an important, but underutilized target for improving vascular function and decreasing brain injury in stroke patients. © 2016 American Physiological Society. Compr Physiol 6:1529-1548, 2016.
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Affiliation(s)
- David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Ibolya Rutkai
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Somhrita Dutta
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Prasad V Katakam
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
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Kovach CP, Al Koborssy D, Huang Z, Chelette BM, Fadool JM, Fadool DA. Mitochondrial Ultrastructure and Glucose Signaling Pathways Attributed to the Kv1.3 Ion Channel. Front Physiol 2016; 7:178. [PMID: 27242550 PMCID: PMC4871887 DOI: 10.3389/fphys.2016.00178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/04/2016] [Indexed: 12/20/2022] Open
Abstract
Gene-targeted deletion of the potassium channel Kv1.3 (Kv1.3−∕−) results in “Super-smeller” mice with a sensory phenotype that includes an increased olfactory ability linked to changes in olfactory circuitry, increased abundance of olfactory cilia, and increased expression of odorant receptors and the G-protein, Golf. Kv1.3−∕− mice also have a metabolic phenotype including lower body weight and decreased adiposity, increased total energy expenditure (TEE), increased locomotor activity, and resistance to both diet- and genetic-induced obesity. We explored two cellular aspects to elucidate the mechanism by which loss of Kv1.3 channel in the olfactory bulb (OB) may enhance glucose utilization and metabolic rate. First, using in situ hybridization we find that Kv1.3 and the insulin-dependent glucose transporter type 4 (GLUT4) are co-localized to the mitral cell layer of the OB. Disruption of Kv1.3 conduction via construction of a pore mutation (W386F Kv1.3) was sufficient to independently translocate GLUT4 to the plasma membrane in HEK 293 cells. Because olfactory sensory perception and the maintenance of action potential (AP) firing frequency by mitral cells of the OB is highly energy demanding and Kv1.3 is also expressed in mitochondria, we next explored the structure of this organelle in mitral cells. We challenged wildtype (WT) and Kv1.3−∕− male mice with a moderately high-fat diet (MHF, 31.8 % kcal fat) for 4 months and then examined OB ultrastructure using transmission electron microscopy. In WT mice, mitochondria were significantly enlarged following diet-induced obesity (DIO) and there were fewer mitochondria, likely due to mitophagy. Interestingly, mitochondria were significantly smaller in Kv1.3−∕− mice compared with that of WT mice. Similar to their metabolic resistance to DIO, the Kv1.3−∕− mice had unchanged mitochondria in terms of cross sectional area and abundance following a challenge with modified diet. We are very interested to understand how targeted disruption of the Kv1.3 channel in the OB can modify TEE. Our study demonstrates that Kv1.3 regulates mitochondrial structure and alters glucose utilization; two important metabolic changes that could drive whole system changes in metabolism initiated at the OB.
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Affiliation(s)
- Christopher P Kovach
- Program in Neuroscience, Florida State UniversityTallahassee, FL, USA; Department of Biological Science, Florida State UniversityTallahassee, FL, USA
| | - Dolly Al Koborssy
- Program in Neuroscience, Florida State University Tallahassee, FL, USA
| | - Zhenbo Huang
- Program in Neuroscience, Florida State University Tallahassee, FL, USA
| | | | - James M Fadool
- Program in Neuroscience, Florida State UniversityTallahassee, FL, USA; Department of Biological Science, Florida State UniversityTallahassee, FL, USA
| | - Debra A Fadool
- Program in Neuroscience, Florida State UniversityTallahassee, FL, USA; Department of Biological Science, Florida State UniversityTallahassee, FL, USA; Institute of Molecular Biophysics, Florida State UniversityTallahassee, FL, USA
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Merdzo I, Rutkai I, Tokes T, Sure VNLR, Katakam PVG, Busija DW. The mitochondrial function of the cerebral vasculature in insulin-resistant Zucker obese rats. Am J Physiol Heart Circ Physiol 2016; 310:H830-8. [PMID: 26873973 DOI: 10.1152/ajpheart.00964.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/03/2016] [Indexed: 12/24/2022]
Abstract
Little is known about mitochondrial functioning in the cerebral vasculature during insulin resistance (IR). We examined mitochondrial respiration in isolated cerebral arteries of male Zucker obese (ZO) rats and phenotypically normal Zucker lean (ZL) rats using the Seahorse XFe24 analyzer. We investigated mitochondrial morphology in cerebral blood vessels as well as mitochondrial and nonmitochondrial protein expression levels in cerebral arteries and microvessels. We also measured reactive oxygen species (ROS) levels in cerebral microvessels. Under basal conditions, the mitochondrial respiration components (nonmitochondrial respiration, basal respiration, ATP production, proton leak, and spare respiratory capacity) showed similar levels among the ZL and ZO groups with the exception of maximal respiration, which was higher in the ZO group. We examined the role of nitric oxide by measuring mitochondrial respiration following inhibition of nitric oxide synthase with N(ω)-nitro-l-arginine methyl ester (l-NAME) and mitochondrial activation after administration of diazoxide (DZ). Both ZL and ZO groups showed similar responses to these stimuli with minor variations.l-NAME significantly increased the proton leak, and DZ decreased nonmitochondrial respiration in the ZL group. Other components were not affected. Mitochondrial morphology and distribution within vascular smooth muscle and endothelium as well as mitochondrial protein levels were similar in the arteries and microvessels of both groups. Endothelial nitric oxide synthase (eNOS) and ROS levels were increased in cerebral microvessels of the ZO. Our study suggests that mitochondrial function is not significantly altered in the cerebral vasculature of young ZO rats, but increased ROS production might be due to increased eNOS in the cerebral microcirculation during IR.
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Affiliation(s)
- Ivan Merdzo
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Ibolya Rutkai
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Tunde Tokes
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Venkata N L R Sure
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Prasad V G Katakam
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
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Akopova O, Nosar V, Gavenauskas B, Bratus L, Kolchinskaya L, Mankovska I, Sagach V. The effect of atp-dependent potassium uptake on mitochondrial functions under acute hypoxia. J Bioenerg Biomembr 2016; 48:67-75. [PMID: 26739597 DOI: 10.1007/s10863-015-9642-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/28/2015] [Indexed: 12/22/2022]
Abstract
The opening of mitochondrial K(+) АТР-channel (mtK(+) АТР-channel) is supposed to be important in the modulation of mitochondrial functions under hypoxia, but the underlying mechanisms have not been clarified yet. The aim of this work was to study the effect of acute hypoxia on mtK(+) АТР-channel activity and to estimate the contribution of the channel in the modulation of mitochondrial functions. MtK(+) АТР-channel activity was assessed polarographically from the rate of State 4 respiration and by potentiometric monitoring of potassium efflux from deenergized mitochondria. It was shown that hypoxia reliably increased mtK(+) АТР-channel activity, which resulted in the changes of respiration rates (increase of State 4 and suppression of State 3 respiration), uncoupling (the decrease of respiratory control ratio) and suppression of phosphorylation. These effects were well mimicked by mtK(+) АТР-channel opener diazoxide (DZ) in isolated rat liver mitochondria. MtK(+) АТР-channel opening in vitro suppressed phosphorylation too, but increased phosphorylation efficiency, while mtK(+) АТР-channel blockers reduced it dramatically. The correlation was established between mtK(+) АТР-channel activity and the endurance of the rats to physical training under hypoxia. Hypoxia improved physical endurance, but treatment by mtK(+) АТР-channel blockers glibenklamide and 5-hydroxydecanoate (5-HD) prior to hypoxia strongly reduced both the channel activity and the endurance limits. This was in accord with the observation that under glibenklamide and 5-HD administration hypoxia failed to restore mtK(+) АТР-channel activity. Based on the experiments, we came to the conclusion that mtK(+) АТР-channel opening played a decisive role in the regulation of energy metabolism under acute hypoxia via the modulation of phosphorylation system in mitochondria.
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Affiliation(s)
- Olga Akopova
- Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, 01601, Kiev, Ukraine.
| | - Valentina Nosar
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Bronislav Gavenauskas
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Larissa Bratus
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Liudmila Kolchinskaya
- Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, 01601, Kiev, Ukraine
| | - Iryna Mankovska
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
| | - Vadim Sagach
- Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, 01601, Kiev, Ukraine
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McCarty MF, DiNicolantonio JJ, O’Keefe JH. Ketosis may promote brain macroautophagy by activating Sirt1 and hypoxia-inducible factor-1. Med Hypotheses 2015; 85:631-9. [DOI: 10.1016/j.mehy.2015.08.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/06/2015] [Accepted: 08/01/2015] [Indexed: 12/25/2022]
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Rutkai I, Dutta S, Katakam PV, Busija DW. Dynamics of enhanced mitochondrial respiration in female compared with male rat cerebral arteries. Am J Physiol Heart Circ Physiol 2015; 309:H1490-500. [PMID: 26276815 DOI: 10.1152/ajpheart.00231.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/13/2015] [Indexed: 02/07/2023]
Abstract
Mitochondrial respiration has never been directly examined in intact cerebral arteries. We tested the hypothesis that mitochondrial energetics of large cerebral arteries ex vivo are sex dependent. The Seahorse XFe24 analyzer was used to examine mitochondrial respiration in isolated cerebral arteries from adult male and female Sprague-Dawley rats. We examined the role of nitric oxide (NO) on mitochondrial respiration under basal conditions, using N(ω)-nitro-l-arginine methyl ester, and following pharmacological challenge using diazoxide (DZ), and also determined levels of mitochondrial and nonmitochondrial proteins using Western blot, and vascular diameter responses to DZ. The components of mitochondrial respiration including basal respiration, ATP production, proton leak, maximal respiration, and spare respiratory capacity were elevated in females compared with males, but increased in both male and female arteries in the presence of the NOS inhibitor. Although acute DZ treatment had little effect on mitochondrial respiration of male arteries, it decreased the respiration in female arteries. Levels of mitochondrial proteins in Complexes I-V and the voltage-dependent anion channel protein were elevated in female compared with male cerebral arteries. The DZ-induced vasodilation was greater in females than in males. Our findings show that substantial sex differences in mitochondrial respiratory dynamics exist in large cerebral arteries and may provide the mechanistic basis for observations that the female cerebral vasculature is more adaptable after injury.
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Affiliation(s)
- Ibolya Rutkai
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Somhrita Dutta
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Prasad V Katakam
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
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Dutta S, Rutkai I, Katakam PVG, Busija DW. The mechanistic target of rapamycin (mTOR) pathway and S6 Kinase mediate diazoxide preconditioning in primary rat cortical neurons. J Neurochem 2015; 134:845-56. [PMID: 26016889 DOI: 10.1111/jnc.13181] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 11/27/2022]
Abstract
We examined the role of the mechanistic target of rapamycin (mTOR) pathway in delayed diazoxide (DZ)-induced preconditioning of cultured rat primary cortical neurons. Neurons were treated for 3 days with 500 μM DZ or feeding medium and then exposed to 3 h of continuous normoxia in Dulbecco's modified eagle medium with glucose or with 3 h of oxygen-glucose deprivation (OGD) followed by normoxia and feeding medium. The OGD decreased viability by 50%, depolarized mitochondria, and reduced mitochondrial respiration, whereas DZ treatment improved viability and mitochondrial respiration, and suppressed reactive oxygen species production, but did not restore mitochondrial membrane potential after OGD. Neuroprotection by DZ was associated with increased phosphorylation of protein kinase B (Akt), mTOR, and the major mTOR downstream substrate, S6 Kinase (S6K). The mTOR inhibitors rapamycin and Torin-1, as well as S6K-targeted siRNA abolished the protective effects of DZ. The effects of DZ on mitochondrial membrane potential and reactive oxygen species production were not affected by rapamycin. Preconditioning with DZ also changed mitochondrial and non-mitochondrial oxygen consumption rates. We conclude that in addition to reducing reactive oxygen species (ROS) production and mitochondrial membrane depolarization, DZ protects against OGD by activation of the Akt-mTOR-S6K pathway and by changes in mitochondrial respiration. Ischemic strokes have limited therapeutic options. Diazoxide (DZ) preconditioning can reduce neuronal damage. Using oxygen-glucose deprivation (OGD), we studied Akt/mTOR/S6K signaling and mitochondrial respiration in neuronal preconditioning. We found DZ protects neurons against OGD via the Akt/mTOR/S6K pathway and alters the mitochondrial and non-mitochondrial oxygen consumption rate. This suggests that the Akt/mTOR/S6k pathway and mitochondria are novel stroke targets.
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Affiliation(s)
- Somhrita Dutta
- Neuroscience Program, Tulane University School of Science and Engineering, New Orleans, Louisiana, USA.,Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Ibolya Rutkai
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Prasad V G Katakam
- Neuroscience Program, Tulane University School of Science and Engineering, New Orleans, Louisiana, USA.,Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - David W Busija
- Neuroscience Program, Tulane University School of Science and Engineering, New Orleans, Louisiana, USA.,Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
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Kim DY, Abdelwahab MG, Lee SH, O’Neill D, Thompson RJ, Duff HJ, Sullivan PG, Rho JM. Ketones prevent oxidative impairment of hippocampal synaptic integrity through KATP channels. PLoS One 2015; 10:e0119316. [PMID: 25848768 PMCID: PMC4388385 DOI: 10.1371/journal.pone.0119316] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 01/29/2015] [Indexed: 12/31/2022] Open
Abstract
Dietary and metabolic therapies are increasingly being considered for a variety of neurological disorders, based in part on growing evidence for the neuroprotective properties of the ketogenic diet (KD) and ketones. Earlier, we demonstrated that ketones afford hippocampal synaptic protection against exogenous oxidative stress, but the mechanisms underlying these actions remain unclear. Recent studies have shown that ketones may modulate neuronal firing through interactions with ATP-sensitive potassium (KATP) channels. Here, we used a combination of electrophysiological, pharmacological, and biochemical assays to determine whether hippocampal synaptic protection by ketones is a consequence of KATP channel activation. Ketones dose-dependently reversed oxidative impairment of hippocampal synaptic integrity, neuronal viability, and bioenergetic capacity, and this action was mirrored by the KATP channel activator diazoxide. Inhibition of KATP channels reversed ketone-evoked hippocampal protection, and genetic ablation of the inwardly rectifying K+ channel subunit Kir6.2, a critical component of KATP channels, partially negated the synaptic protection afforded by ketones. This partial protection was completely reversed by co-application of the KATP blocker, 5-hydoxydecanoate (5HD). We conclude that, under conditions of oxidative injury, ketones induce synaptic protection in part through activation of KATP channels.
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Affiliation(s)
- Do Young Kim
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
- * E-mail:
| | - Mohammed G. Abdelwahab
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
| | - Soo Han Lee
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
| | - Derek O’Neill
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph’s Hospital & Medical Center, Phoenix, Arizona, United States of America
| | - Roger J. Thompson
- Departments of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Henry J. Duff
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Patrick G. Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Jong M. Rho
- Departments of Pediatrics and Clinical Neurosciences, Alberta Children’s Hospital, Calgary, Alberta, Canada
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Mitochondrial biology, targets, and drug delivery. J Control Release 2015; 207:40-58. [PMID: 25841699 DOI: 10.1016/j.jconrel.2015.03.036] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 02/07/2023]
Abstract
In recent years, mitochondrial medicine has emerged as a new discipline resting at the intersection of mitochondrial biology, pathology, and pharmaceutics. The central role of mitochondria in critical cellular processes such as metabolism and apoptosis has placed mitochondria at the forefront of cell science. Advances in mitochondrial biology have revealed that these organelles continually undergo fusion and fission while functioning independently and in complex cellular networks, establishing direct membrane contacts with each other and with other organelles. Understanding the diverse cellular functions of mitochondria has contributed to understanding mitochondrial dysfunction in disease states. Polyplasmy and heteroplasmy contribute to mitochondrial phenotypes and associated dysfunction. Residing at the center of cell biology, cellular functions, and disease pathology and being laden with receptors and targets, mitochondria are beacons for pharmaceutical modification. This review presents the current state of mitochondrial medicine with a focus on mitochondrial function, dysfunction, and common disease; mitochondrial receptors, targets, and substrates; and mitochondrial drug design and drug delivery with a focus on the application of nanotechnology to mitochondrial medicine. Mitochondrial medicine is at the precipice of clinical translation; the objective of this review is to aid in the advancement of mitochondrial medicine from infancy to application.
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Da-bu-yin-wan and qian-zheng-san to neuroprotect the mouse model of Parkinson's disease. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:729195. [PMID: 25610480 PMCID: PMC4290155 DOI: 10.1155/2014/729195] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/03/2014] [Indexed: 12/01/2022]
Abstract
Da-Bu-Yin-Wan (DBYW) and Qian-Zheng-San (QZS), two classic traditional Chinese medicinal formulas, were clinically employed to treat Parkinson's disease (PD). Our previous studies demonstrated neuroprotective effects of them on mitochondrial function in PD mice induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The purpose of this research was to investigate their possible mechanisms in the light of mitochondrial ATP-sensitive potassium (mitoKATP) channels. The neuroprotective effect of DBYW and QZS on dopamine (DA) neurons in substantia nigra (SN) in the MPTP-induced PD mice was investigated by behavioral test (pole test) and immunohistochemistry. Adenosine triphosphate (ATP) level in the midbrain tissue was detected by firefly luciferase method. MitoKATP channel subunits SUR1 and Kir6.2 mRNA and protein expressions were tested by real-time PCR (RT-PCR) and Western blot. It was observed that DBYW and/or QZS served to ameliorate MPTP-induced behavioral impairment and prevent the loss of substantia nigra dopamine neurons, as well as increase ATP level in the midbrain tissue and downregulate SUR1 expression at mRNA and protein levels with no marked influence on Kir6.2. We concluded that DBYW and QZS exhibit neuroprotective effects probably through the regulation of ATP level and mitoKATP channel subunit expressions.
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Leandra C, Tasca CI, Boeck CR. The Role of NMDA Receptors in the Development of Brain Resistance through Pre- and Postconditioning. Aging Dis 2014; 5:430-41. [PMID: 25489494 DOI: 10.14336/ad.2014.0500430] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/30/2014] [Accepted: 02/09/2014] [Indexed: 11/01/2022] Open
Abstract
Brain tolerance or resistance can be achieved by interventions before and after injury through potential toxic agents used in low stimulus or dose. For brain diseases, the neuroprotection paradigm desires an attenuation of the resulting motor, cognitive, emotional, or memory deficits following the insult. Preconditioning is a well-established experimental and clinical translational strategy with great beneficial effects, but limited applications. NMDA receptors have been reported as protagonists in the adjacent cellular mechanisms contributing to the development of brain tolerance. Postconditioning has recently emerged as a new neuroprotective strategy, which has shown interesting results when applied immediately, i.e. several hours to days, after a stroke event. Investigations using chemical postconditioning are still incipient, but nevertheless represent an interesting and promising clinical strategy. In the present review pre- and postconditioning are discussed as neuroprotective paradigms and the focus of our attention lies on the participation of NMDA receptors proteins in the processes related to neuroprotection.
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Affiliation(s)
| | - Carla Inês Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil
| | - Carina Rodrigues Boeck
- Laboratório de Biologia Celular e Molecular, Instituto Nacional de Ciência e Tecnologia Translacional em Medicina (INCT-TM), Programa de Pós-graduação Ciências da Saúde, Universidade do Extremo Sul Catarinense-UNESC, Criciúma, 88806-000, SC, Brazil
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Akopova OV, Kolchinskaya LI, Nosar VI, Bouryi VA, Mankovska IN, Sagach VF. Effect of potential-dependent potassium uptake on production of reactive oxygen species in rat brain mitochondria. BIOCHEMISTRY (MOSCOW) 2014; 79:44-53. [PMID: 24512663 DOI: 10.1134/s0006297914010076] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effect of potential-dependent potassium uptake on reactive oxygen species (ROS) generation in mitochondria of rat brain was studied. It was found that the effect of K+ uptake on ROS production in the brain mitochondria under steady-state conditions (state 4) was determined by potassium-dependent changes in the membrane potential of the mitochondria (ΔΨm). At K+ concentrations within the range of 0-120 mM, an increase in the initial rate of K(+)-uptake into the matrix resulted in a decrease in the steady-state rate of ROS generation due to the K(+)-induced depolarization of the mitochondrial membrane. The selective blockage of the ATP-dependent potassium channel (K(ATP)(+)-channel) by glibenclamide and 5-hydroxydecanoate resulted in an increase in ROS production due to the membrane repolarization caused by partial inhibition of the potential-dependent K+ uptake. The ATP-dependent transport of K+ was shown to be ~40% of the potential-dependent K+ uptake in the brain mitochondria. Based on the findings of the experiments, the potential-dependent transport of K+ was concluded to be a physiologically important regulator of ROS generation in the brain mitochondria and that the functional activity of the native K(ATP)(+)-channel in these organelles under physiological conditions can be an effective tool for preventing ROS overproduction in brain neurons.
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Affiliation(s)
- O V Akopova
- Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, 01601, Ukraine.
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Rutkai I, Katakam PVG, Dutta S, Busija DW. Sustained mitochondrial functioning in cerebral arteries after transient ischemic stress in the rat: a potential target for therapies. Am J Physiol Heart Circ Physiol 2014; 307:H958-66. [PMID: 25063798 DOI: 10.1152/ajpheart.00405.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The objective of the present study was to determine whether mitochondrial function in the cerebral vasculature is maintained after transient middle cerebral artery (MCA) occlusion (tMCAO) in rats. Sprague-Dawley rats were exposed to 90 min of tMCAO followed by 4 or 48 h of reperfusion. MCAs from ischemic (ipsilateral) and nonischemic (contralateral) sides were compared with control MCAs from sham-operated rats. We determined 1) vasoreactivity to diazoxide (DZ; a mitochondrial ATP-activated K(+) channel opener), ACh, bradykinin (BK), serotonin, and sodium nitroprusside; 2) levels of mitochondrial and nonmitochondrial proteins and mitochondrial DNA; and 3) vascular levels of tetramethylrhodamine ethyl ester (an indicator of mitochondrial membrane potential). All dilator responses, including those with DZ, were intact 4 h post-tMCAO. Dilator responses to ACh, BK, and sodium nitroprusside were reduced in ipsilateral MCAs at 48 h compared with contralateral MCAs, but DZ responses were comparable with control MCAs. Surprisingly, contralateral responses to ACh, BK, and serotonin were reduced compared with control MCAs at 48 h. Ipsilateral vasodilation to DZ at 48 h was eliminated by endothelial denudation and endothelial nitric oxide synthase (eNOS) inhibition but was only reduced in control MCAs. Mitochondrial proteins, phosphorylated eNOS, mitochondrial DNA, and mitochondrial membrane potential were higher in ipsilateral compared with contralateral MCAs. In conclusion, contrary to conventional wisdom, mitochondria remain functional for at least 48 h after severe ischemic stress in MCAs, and DZ-induced dilation is preserved due to maintained mitochondrial mass, probably in the endothelium, and eNOS signaling. Our findings support the concept that functioning vascular mitochondria are an unexpected target for novel stroke therapies.
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Affiliation(s)
- Ibolya Rutkai
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Prasad V G Katakam
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Somhrita Dutta
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
| | - David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana
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Akopova OV, Nosar' VI, Kolchinskaia LI, Man'kovskaia IN, Malysheva MK, Sagach VF. [Estimation of ATP-dependent K(+)-channel contribution to potential-dependent potassium uptake in the rat brain mitochondria]. UKRAINIAN BIOCHEMICAL JOURNAL 2014; 86:21-8. [PMID: 24834715 DOI: 10.15407/ubj86.01.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The effect of potassium on state 4 respiration (substrate oxidation in the absence of ADP) was investigated. It was shown that potential-dependent potassium uptake in the brain mitochondria results in mitochondrial depolarization. Taking into account depolarization effect of potassium, the contribution of the endogenous proton leak as well as K(+)-uptake to the respiration rate was calculated. It was shown that such estimation allows the share of ATP-dependent potassium channel contribution to potential-dependent potassium uptake to be determined by polarographic method.
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Busija DW, Katakam PV. Mitochondrial mechanisms in cerebral vascular control: shared signaling pathways with preconditioning. J Vasc Res 2014; 51:175-89. [PMID: 24862206 PMCID: PMC4149841 DOI: 10.1159/000360765] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 02/19/2014] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial-initiated events protect the neurovascular unit against lethal stress via a process called preconditioning, which independently promotes changes in cerebrovascular tone through shared signaling pathways. Activation of adenosine triphosphate (ATP)-dependent potassium channels on the inner mitochondrial membrane (mitoKATP channels) is a specific and dependable way to induce protection of neurons, astroglia, and cerebral vascular endothelium. Through the opening of mitoKATP channels, mitochondrial depolarization leads to activation of protein kinases and transient increases in cytosolic calcium (Ca(2+)) levels that activate terminal mechanisms that protect the neurovascular unit against lethal stress. The release of reactive oxygen species from mitochondria has similar protective effects. Signaling elements of the preconditioning pathways also are involved in the regulation of vascular tone. Activation of mitoKATP channels in cerebral arteries causes vasodilation, with cell-specific contributions from the endothelium, vascular smooth muscles, and nerves. Preexisting chronic conditions, such as insulin resistance and/or diabetes, prevent preconditioning and impair relaxation to mitochondrial-centered responses in cerebral arteries. Surprisingly, mitochondrial activation after anoxic or ischemic stress appears to protect cerebral vascular endothelium and promotes the restoration of blood flow; therefore, mitochondria may represent an important, but underutilized target in attenuating vascular dysfunction and brain injury in stroke patients.
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Affiliation(s)
- David W Busija
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, La., USA
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Zhang L, Gao X, Yuan X, Dong H, Zhang Z, Wang S. Mitochondrial Calcium Uniporter Opener Spermine Attenuates the Cerebral Protection of Diazoxide through Apoptosis in Rats. J Stroke Cerebrovasc Dis 2014; 23:829-35. [DOI: 10.1016/j.jstrokecerebrovasdis.2013.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 06/26/2013] [Accepted: 07/05/2013] [Indexed: 11/16/2022] Open
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Akopova OV, Nosar' VI, Man'kovskaia IN, Sagach VF. [The effect of Ca(2+)-induced opening of cyclosporine-sensitive pore on the oxygen consumption and functional state of rat liver mitochondria]. UKRAINIAN BIOCHEMICAL JOURNAL 2014; 85:37-49. [PMID: 24479321 DOI: 10.15407/ubj85.05.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The effect of Ca(2+)-induced opening of cyclosporine-sensitive pore (mitochondrial permeability transition pore, MPTP) on the oxygen consumption and mitochondrial functional state was studied in the rat liver mitochondria. It was shown that, with the use of glutamate as oxidation substrate, in the absence of depolarization MPTP opening results in the increase of steady state respiration rate because of the activation of cyclosporine-sensitive Ca2+/H(+)-exchange and Ca2+ cycling, which was supported by the simultaneous work of MPTP and Ca(2+)-uniporter. With the aid of selective blockers, cyclosporine A and ruthenium red, it was shown that MPTP and Ca(2+)-uniporter contribute equally to the Ca(2+)-cycling and mitochondrial respiration. It was shown that bioenergetic effects of MPTP opening under steady state conditions (increase in the oxygen consumption rate under substrate oxidation without ADP, decrease in respiratory control ratio as well as the effectiveness of ATP synthesis, P/O) are close to the functional alterations, which result from the increase of endogenous proton conductance of mitochondrial membrane. Uncoupling effect of MPTP opening, by itself, had no effect on phosphorylation rate, which remains relatively stable because the fall of P/O is compensated by the activation of respiratory chain and the increase in the rate of state 3 respiration. It was concluded that under physiologically normal conditions MPTP might function as the endogenous mechanism of mild uncoupling of respiratory chain.
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Effect of Valinomycin-Induced Potassium Influx on the Formation of Reactive Oxygen Species in the Rat Brain Mitochondria. NEUROPHYSIOLOGY+ 2013. [DOI: 10.1007/s11062-013-9384-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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38
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Potassium channel in the mitochondria of human keratinocytes. J Invest Dermatol 2013; 134:764-772. [PMID: 24126847 DOI: 10.1038/jid.2013.422] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 08/21/2013] [Accepted: 09/04/2013] [Indexed: 11/08/2022]
Abstract
The activation of mitochondrial potassium channels induces cytoprotection in various cell types. Hence, the identification of ion channels present in the inner mitochondrial membrane of keratinocytes is important in distinguishing possible protective mechanisms in these cells. In this paper, inner membrane mitochondrial ion channels of the human keratinocyte HaCaT cell line were investigated using a patch-clamp technique. We observed potassium-selective channel activity with a conductance of 83 pS at positive voltages. The I-V curve indicates that the observed channel has rectifying properties. Moreover, the channel activity was inhibited by acidic pH and 1 mM lidocaine. Using reverse transcriptase-PCR, we found an mRNA transcript for the TASK-3 (tandem pore domain acid-sensitive K channels) channel. We observed co-localization of the TASK-3 protein and a mitochondrial marker in the mitochondria of HaCaT cells. Additionally, we showed that TASK-3 knockdown HaCaT cells markedly decreased viability after UVB radiation exposure compared with control cells. In summary, the single-channel activity and properties of a mitochondrial potassium channel in a keratinocyte HaCaT cell line have been described.
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Jiang X, Huang Y, Lin W, Gao D, Fei Z. Protective effects of hydrogen sulfide in a rat model of traumatic brain injury via activation of mitochondrial adenosine triphosphate–sensitive potassium channels and reduction of oxidative stress. J Surg Res 2013; 184:e27-35. [DOI: 10.1016/j.jss.2013.03.067] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 01/28/2023]
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40
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Lee M, McGeer E, Kodela R, Kashfi K, McGeer PL. NOSH-aspirin (NBS-1120), a novel nitric oxide and hydrogen sulfide releasing hybrid, attenuates neuroinflammation induced by microglial and astrocytic activation: A new candidate for treatment of neurodegenerative disorders. Glia 2013; 61:1724-34. [DOI: 10.1002/glia.22553] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/27/2013] [Accepted: 06/27/2013] [Indexed: 12/16/2022]
Affiliation(s)
- Moonhee Lee
- Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver; BC; V6T 1Z3; Canada
| | - Edith McGeer
- Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver; BC; V6T 1Z3; Canada
| | - Ravinder Kodela
- Department of Physiology; Pharmacology and Neuroscience, Sophie Davis School of Biomedical Education, City University of New York Medical School; New York; New York; 10031
| | - Khosrow Kashfi
- Department of Physiology; Pharmacology and Neuroscience, Sophie Davis School of Biomedical Education, City University of New York Medical School; New York; New York; 10031
| | - Patrick L. McGeer
- Kinsmen Laboratory of Neurological Research; University of British Columbia; Vancouver; BC; V6T 1Z3; Canada
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41
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Olszewska A, Szewczyk A. Mitochondria as a pharmacological target: magnum overview. IUBMB Life 2013; 65:273-81. [PMID: 23441041 DOI: 10.1002/iub.1147] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 12/14/2012] [Indexed: 12/30/2022]
Abstract
Mitochondria, responsible for energy metabolism within the cell, act as signaling organelles. Mitochondrial dysfunction may lead to cell death and oxidative stress and may disturb calcium metabolism. Additionally, mitochondria play a pivotal role in cardioprotective phenomena and a variety of neurodegenerative disorders ranging from Parkinson's to Alzheimer's disease. Mitochondrial DNA mutations may lead to impaired respiration. Hence, targeting the mitochondria with drugs offers great potential for new therapeutic approaches. The purpose of this overview is to present the recent state of knowledge concerning the interactions of various substances with mitochondria.
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Affiliation(s)
- Anna Olszewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland.
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Yamanaka R, Shindo Y, Hotta K, Suzuki K, Oka K. NO/cGMP/PKG signaling pathway induces magnesium release mediated by mitoKATP channel opening in rat hippocampal neurons. FEBS Lett 2013; 587:2643-8. [PMID: 23831575 DOI: 10.1016/j.febslet.2013.06.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/26/2013] [Accepted: 06/26/2013] [Indexed: 11/19/2022]
Abstract
Intracellular Mg²⁺ concentration ([Mg²⁺]i) and NO regulate cell survival and death. To reveal the involvement of NO in intracellular Mg²⁺ regulation, we visualized intracellular Mg²⁺ using the fluorescent Mg²⁺ indicator KMG-104-AM in rat hippocampal neurons. Pharmacological experiments using SNAP, 8-Br-cGMP, diazoxide and several inhibitors revealed that the NO/cGMP/Protein kinsase G (PKG) signaling pathway triggers an increase in [Mg²⁺]i, and that Mg²⁺ mobilization is due to Mg²⁺ release from mitochondria induced by mitoKATP channel opening. In addition, Mg²⁺ release is potentiated by the positive feedback loop including mitoKATP channel opening, mitochondrial depolarization and PKC activation.
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Affiliation(s)
- Ryu Yamanaka
- Center for Biosciences and Informatics, School of Fundamental Science and Technology, Keio University, Yokohama, Kanagawa, Japan
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Dudek M, Bilska-Wilkosz A, Knutelska J, Mogilski S, Bednarski M, Zygmunt M, Iciek M, Sapa J, Bugajski D, Filipek B, Włodek L. Are anti-inflammatory properties of lipoic acid associated with the formation of hydrogen sulfide? Pharmacol Rep 2013; 65:1018-24. [DOI: 10.1016/s1734-1140(13)71084-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 02/05/2013] [Indexed: 01/02/2023]
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Zhou L, Wang X, Xue W, Xie K, Huang Y, Chen H, Gong G, Zeng Y. Beneficial effects of hydrogen-rich saline against spinal cord ischemia-reperfusion injury in rabbits. Brain Res 2013; 1517:150-60. [PMID: 23603405 DOI: 10.1016/j.brainres.2013.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/26/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
Abstract
Hydrogen-rich saline (HS) is reported to be a new therapeutic agent in ischemia-reperfusion (I/R)-induced organ damage. The present study was designed to investigate the beneficial effects of HS against spinal cord I/R injury and its associated mechanisms. Spinal cord ischemia was induced by infrarenal aortic occlusion for 20min in male New Zealand white rabbits. Different doses of HS were intravenously (i.v.) administered at 5min before or after the beginning of reperfusion. Moreover, the roles of mitochondrial ATP-sensitive potassium channels (mitoKATP), oxidative stress, inflammatory cytokines and apoptosis was assessed. Here, we found that I/R-challenged rabbits exhibited significant spinal cord injury characterized by the decreased numbers of normal motor neurons and hind-limb motor dysfunction, which was significantly ameliorated by 5mL/kg and 10mL/kg HS treatment before reperfusion or 10mL/kg HS treatment after reperfusion. However, the protective effects of HS treatment in spinal cord I/R injury were partially abolished by the selective mitoKATP channel blocker 5-hydroxydecanoate (5-HD). Moreover, we showed that the beneficial effects of 10mL/kg HS treatment against spinal cord I/R damage were associated with the decreased levels of oxidative products [8-iso-prostaglandin F2α (8-iso-PGF2α) and malondialdehyde (MDA)] and pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1)], as well as the increased activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] in serum at 6h, 12h, 24h, 48h and 72h after reperfusion and in spinal cord at 72h after reperfusion. Furthermore, HS treatment (10mL/kg) reduced caspase-3 activity in the spinal cord of this model. Thus, HS may be an effective therapeutic agent for spinal cord I/R injury via activation of mitoKATP channels as well as reduction of oxidative stress, inflammatory cytokines and apoptosis.
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Affiliation(s)
- Leshun Zhou
- Department of Anesthesiology, General Hospital of Chengdu Military Command, Chengdu 610083, Sichuan Province, PR China
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Akopova OV, Kolchinskaya LI, Nosar VI, Bouryi VA, Mankovskaya IN, Sagach VF. Effect of potential-dependent potassium uptake on calcium accumulation in rat brain mitochondria. BIOCHEMISTRY (MOSCOW) 2013; 78:80-90. [PMID: 23379563 DOI: 10.1134/s0006297913010100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of potential-dependent potassium uptake at 0-120 mM K+ on matrix Ca2+ accumulation in rat brain mitochondria was studied. An increase in oxygen consumption and proton extrusion rates as well as increase in matrix pH with increase in K+ content in the medium was observed due to K+ uptake into the mitochondria. The accumulation of Ca2+ was shown to depend on K+ concentration in the medium. At K+ concentration ≤30 mM, Ca2+ uptake is decreased due to K+-induced membrane depolarization, whereas at higher K+ concentrations, up to 120 mM K+, Ca2+ uptake is increased in spite of membrane depolarization caused by matrix alkalization due to K+ uptake. Mitochondrial K+(ATP)-channel blockers (glibenclamide and 5-hydroxydecanoic acid) diminish K+ uptake as well as K+-induced depolarization and matrix alkalization, which results in attenuation of the potassium-induced effects on matrix Ca2+ uptake, i.e. increase in Ca2+ uptake at low K+ content in the medium due to the smaller membrane depolarization and decrease in Ca2+ uptake at high potassium concentrations because of restricted rise in matrix pH. The results show the importance of potential-dependent potassium uptake, and especially the K+(ATP) channel, in the regulation of calcium accumulation in rat brain mitochondria.
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Affiliation(s)
- O V Akopova
- Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev-24, Ukraine.
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Neuroprotective role of ATP-sensitive potassium channels in cerebral ischemia. Acta Pharmacol Sin 2013; 34:24-32. [PMID: 23123646 DOI: 10.1038/aps.2012.138] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are weak, inward rectifiers that couple metabolic status to cell membrane electrical activity, thus modulating many cellular functions. An increase in the ADP/ATP ratio opens K(ATP) channels, leading to membrane hyperpolarization. K(ATP) channels are ubiquitously expressed in neurons located in different regions of the brain, including the hippocampus and cortex. Brief hypoxia triggers membrane hyperpolarization in these central neurons. In vivo animal studies confirmed that knocking out the Kir6.2 subunit of the K(ATP) channels increases ischemic infarction, and overexpression of the Kir6.2 subunit reduces neuronal injury from ischemic insults. These findings provide the basis for a practical strategy whereby activation of endogenous K(ATP) channels reduces cellular damage resulting from cerebral ischemic stroke. K(ATP) channel modulators may prove to be clinically useful as part of a combination therapy for stroke management in the future.
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Rodriguez-Pallares J, Parga JA, Joglar B, Guerra MJ, Labandeira-Garcia JL. Mitochondrial ATP-sensitive potassium channels enhance angiotensin-induced oxidative damage and dopaminergic neuron degeneration. Relevance for aging-associated susceptibility to Parkinson's disease. AGE (DORDRECHT, NETHERLANDS) 2012; 34:863-880. [PMID: 21713375 PMCID: PMC3682060 DOI: 10.1007/s11357-011-9284-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 06/15/2011] [Indexed: 05/31/2023]
Abstract
Recent studies have shown that renin-angiotensin system overactivation is involved in the aging process in several tissues as well as in longevity and aging-related degenerative diseases by increasing oxidative damage and inflammation. We have recently shown that angiotensin II enhances dopaminergic degeneration by increasing levels of reactive oxygen species and neuroinflammation, and that there is an aging-related increase in angiotensin II activity in the substantia nigra in rats, which may constitute a major factor in the increased risk of Parkinson's disease with aging. The mechanisms involved in the above mentioned effects and particularly a potential angiotensin-mitochondria interaction have not been clarified. The present study revealed that activation of mitochondrial ATP-sensitive potassium channels [mitoK(ATP)] may play a major role in the angiotensin II-induced effects on aging and neurodegeneration. Inhibition of mitoK(ATP) channels with 5-hydroxydecanoic acid inhibited the increase in dopaminergic cell death induced by angiotensin II, as well as the increase in superoxide/superoxide-derived reactive oxygen species levels and the angiotensin II-induced decrease in the mitochondrial inner membrane potential in cultured dopaminergic neurons. The present study provides data for considering brain renin-angiotensin system and mitoK(ATP) channels as potential targets for protective therapy in aging-associated diseases such as Parkinson's disease.
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Affiliation(s)
- Jannette Rodriguez-Pallares
- />Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
- />Networking Research Center on Neurodegenerative Diseases (CIBERNED), Santiago de Compostela, Spain
| | - Juan Andres Parga
- />Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
- />Networking Research Center on Neurodegenerative Diseases (CIBERNED), Santiago de Compostela, Spain
| | - Belen Joglar
- />Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
- />Networking Research Center on Neurodegenerative Diseases (CIBERNED), Santiago de Compostela, Spain
| | - Maria Jose Guerra
- />Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
- />Networking Research Center on Neurodegenerative Diseases (CIBERNED), Santiago de Compostela, Spain
| | - Jose Luis Labandeira-Garcia
- />Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Faculty of Medicine, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
- />Networking Research Center on Neurodegenerative Diseases (CIBERNED), Santiago de Compostela, Spain
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Trono D, Soccio M, Laus MN, Pastore D. Potassium channel-oxidative phosphorylation relationship in durum wheat mitochondria from control and hyperosmotic-stressed seedlings. PLANT, CELL & ENVIRONMENT 2011; 34:2093-108. [PMID: 21819416 DOI: 10.1111/j.1365-3040.2011.02407.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Durum wheat mitochondria (DWM) possess an ATP-inhibited K(+) channel, the plant mitoK(ATP) (PmitoK(ATP) ), which is activated under environmental stress to control mitochondrial ROS production. To do this, PmitoK(ATP) collapses membrane potential (ΔΨ), thus suggesting mitochondrial uncoupling. We tested this point by studying oxidative phosphorylation (OXPHOS) in DWM purified from control seedlings and from seedlings subjected both to severe mannitol and NaCl stress. In severely-stressed DWM, the ATP synthesis via OXPHOS, continuously monitored by a spectrophotometric assay, was about 90% inhibited when the PmitoK(ATP) was activated by KCl. Contrarily, in control DWM, although PmitoK(ATP) collapsed ΔΨ, ATP synthesis, as well as coupling [respiratory control (RC) ratio and ratio between phosphorylated ADP and reduced oxygen (ADP/O)] checked by oxygen uptake experiments, were unaffected. We suggest that PmitoK(ATP) may play an important defensive role at the onset of the environmental/oxidative stress by preserving energy in a crucial moment for cell and mitochondrial bioenergetics. Consistently, under moderate mannitol stress, miming an early stress condition, the channel may efficiently control reactive oxygen species (ROS) generation (about 35-fold from fully open to closed state) without impairing ATP synthesis. Anyway, if the stress significantly proceeds, the PmitoK(ATP) becomes fully activated by decrease of ATP concentration (25-40%) and increase of activators [free fatty acids (FFAs) and superoxide anion], thus impairing ATP synthesis.
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Affiliation(s)
- Daniela Trono
- CRA - Centro di Ricerca per la Cerealicoltura, S.S. 16 Km 675, Dipartimento di Scienze Agroambientali, Chimica e Difesa Vegetale, Università di Foggia, Via Napoli 25, Italy
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Song JG, Hahm KD, Kim YK, Leem JG, Lee C, Jeong SM, Park PH, Shin JW. Adenosine triphosphate-sensitive potassium channel blockers attenuate the antiallodynic effect of R-PIA in neuropathic rats. Anesth Analg 2011; 112:1494-9. [PMID: 21543780 DOI: 10.1213/ane.0b013e318212b833] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Nerve injury can generate neuropathic pain. The accompanying mechanical allodynia may be reduced by the intrathecal administration of adenosine. The neuroprotective effects of adenosine are mediated by the adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channel. We assessed the relationship between the adenosine A1 receptor agonist, N⁶-(R)-phenylisopropyl adenosine (R-PIA), and K(ATP) channels to determine whether the antiallodynic effects of R-PIA are also mediated through K(ATP) channels in a rat nerve ligation injury model of neuropathic pain. METHODS Mechanical allodynia was induced by tight ligation of the left lumbar fifth and sixth spinal nerves. Mechanical allodynia in the left hindpaw was evaluated using von Frey filaments to measure withdrawal thresholds. R-PIA (0.5, 1, or 2 μg) was administered intrathecally to induce antiallodynia. We assessed whether pretreatment with the K(ATP) channel blockers glibenclamide or 5-hydroxydecanoate reversed the antiallodynic effect of R-PIA. Also, we evaluated whether diazoxide, a K(ATP) channel opener, had an antiallodynic effect and promoted the antiallodynic effect of R-PIA. Lastly, we investigated whether the voltage-activated K channel blocker 4-aminopyridine attenuated the effect of R-PIA. RESULTS Intrathecal R-PIA produced maximal antiallodynia at 2 μg (P < 0.05). Intrathecal pretreatment with glibenclamide and intraperitoneal pretreatment 5-hydroxydecanoate significantly reduced the antiallodynic effect of R-PIA. Diazoxide produced an antiallodynic effect and also enhanced the antiallodynic action of R-PIA. 4-Aminopyridine had no effect on the antiallodynic action of R-PIA. CONCLUSIONS The antiallodynic effects of adenosine A1 receptor stimulation may be related to K(ATP) channel activity in a rat model of nerve ligation injury.
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Affiliation(s)
- Jun-Gol Song
- Department of Anesthesiology and Pain Medicine, University of Ulsan College of Medicine, Asan Medical Center, Songpa-gu, Seoul, 138-736, Korea.
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Jiang K, Wang J, Zhao C, Feng M, Shen Z, Yu Z, Xia Z. Regulation of gap junctional communication by astrocytic mitochondrial K(ATP) channels following neurotoxin administration in in vitro and in vivo models. Neurosignals 2011; 19:63-74. [PMID: 21474909 DOI: 10.1159/000323575] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 12/13/2010] [Indexed: 11/19/2022] Open
Abstract
It is known that neuronal ATP-sensitive potassium (K(ATP)) channels and astrocytic gap junctions (GJs) are involved in the mechanism underlying neurodisorders. The K(ATP) channels exist also in glial cells, and the objective of this study was to determine whether the astrocytic K(ATP) channels exert their effect on neurotoxin-induced neurodysfunction through regulating the astrocytic GJ function. The results showed that diazoxide, a selective mitochondrial K(ATP) (mitoK(ATP)) channel opener, enhanced the GJ coupling, but 5-hydroxydecanoate, a selective mitoK(ATP) channel blocker that significantly inhibits GJ coupling in vitro did not. Activation of astrocytic mitoK(ATP) channels alleviated kainic acid-induced dysfunction of GJ intercellular communication. Finally, activation of mitoK(ATP) channels improved the astrocytic GJ coupling in the hippocampus after seizures due to the colabeling of GJ subunit connexin 43 and connexin 45 with glial marker and was increased substantially by the administration of diazoxide. Western blot demonstrated that the mitoK(ATP) channels regulated the expression of connexin 43 (P2; active form) and connexin 45 in the epileptic hippocampus. These findings demonstrate that activation of astrocytic mitoK(ATP) channels improves the GJ function in astrocytes, indicating that the effect of the astrocytic mitoK(ATP) channels on neurotoxin-induced neurodysfunction might be, in part, through the regulation of the GJ-coupled spatial buffering in the hippocampus.
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Affiliation(s)
- Kewen Jiang
- Department of Neurology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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