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Gómez Del Val A, Contreras C, Muñoz M, Sáenz-Medina J, Mohamed M, Rivera L, Sánchez A, Prieto D. Activation of mitoK ATP channels induces penile vasodilation and inhibits mitochondrial respiration and ROS production: Role of NO. Free Radic Biol Med 2024; 217:15-28. [PMID: 38522485 DOI: 10.1016/j.freeradbiomed.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/17/2024] [Accepted: 03/12/2024] [Indexed: 03/26/2024]
Abstract
OBJECTIVE Mitochondrial ATP-sensitive K+ (mitoKATP) channels are involved in neuronal and cardiac protection from ischemia and oxidative stress. Penile erection is a neurovascular event mediated by relaxation of the erectile tissue via nitric oxide (NO) released from nerves and endothelium. In the present study, we investigated whether mitoKATP channels play a role in the control of penile vascular tone and mitochondrial dynamics, and the involvement of NO. METHODS The effect of the selective mitoKATP activator BMS191095 was examined on vascular tone, on mitochondrial bioenergetics by real-time measurements with Agilent Seahorse and on ROS production by MitoSOX fluorescence in freshly isolated microarteries. RESULTS BMS191095 and diazoxide relaxed penile arteries, BMS191095 being one order of magnitude more potent. BMS191095-induced relaxations were reduced by mechanical endothelium removal and by inhibitors of the nitric oxide synthase (NOS) and PI3K enzymes. The NO-dependent component of the relaxation to BMS191095 was impaired in penile arteries from insulin resistant obese rats. The blockers of mitoKATP channel 5-HD, sarcolemma KATP (sarcKATP) channel glibenclamide, and large conductance Ca2+-activated K+ (BKCa) channel iberiotoxin, inhibited relaxations to BMS191095 and to the NO donor SNAP. BMS191095 reduced the mitochondrial bioenergetic profile of penile arteries and attenuated mitochondrial ROS production. Blockade of endogenous NO impaired and exogenous NO mimicked, respectively, the inhibitory effects of BMS191095 on basal respiration and oxygen consumed for ATP synthesis. Exogenous NO exhibited dual inhibitory/stimulatory effects on mitochondrial respiration. CONCLUSIONS These results demonstrate that selective activation of mitoKATP channels causes penile vasodilation, attenuates ROS production and inhibits mitochondrial respiration in part by releasing endothelial NO. These mechanisms couple blood flow and metabolism in penile arterial wall and suggest that activation of vascular mitoKATP channels may protect erectile tissue against ischemic injury.
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Affiliation(s)
- Alfonso Gómez Del Val
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Cristina Contreras
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Mercedes Muñoz
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Javier Sáenz-Medina
- Department of Urology, Puerta de Hierro-Majadahonda University Hospital, 28222, Majadahonda, Spain
| | - Mariam Mohamed
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Luis Rivera
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Ana Sánchez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
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Naima J, Ohta Y. Potassium Ions Decrease Mitochondrial Matrix pH: Implications for ATP Production and Reactive Oxygen Species Generation. Int J Mol Sci 2024; 25:1233. [PMID: 38279231 PMCID: PMC10815940 DOI: 10.3390/ijms25021233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/05/2024] [Accepted: 01/14/2024] [Indexed: 01/28/2024] Open
Abstract
Potassium (K+) is the most abundant cation in the cytosol and is maintained at high concentrations within the mitochondrial matrix through potassium channels. However, many effects of K+ at such high concentrations on mitochondria and the underlying mechanisms remain unclear. This study aims to elucidate these effects and mechanisms by employing fluorescence imaging techniques to distinguish and precisely measure signals inside and outside the mitochondria. We stained the mitochondrial matrix with fluorescent dyes sensitive to K+, pH, reactive oxygen species (ROS), and membrane potential in plasma membrane-permeabilized C6 cells and isolated mitochondria from C6 cells. Fluorescence microscopy facilitated the accurate measurement of fluorescence intensity inside and outside the matrix. Increasing extramitochondrial K+ concentration from 2 mM to 127 mM led to a reduction in matrix pH and a decrease in the generation of highly reactive ROS. In addition, elevated K+ levels electrically polarized the inner membrane of the mitochondria and promoted efficient ATP synthesis via FoF1-ATPase. Introducing protons (H+) into the matrix through phosphate addition led to further mitochondrial polarization, and this effect was more pronounced in the presence of K+. K+ at high concentrations, reaching sub-hundred millimolar levels, increased H+ concentration within the matrix, suppressing ROS generation and boosting ATP synthesis. Although this study does not elucidate the role of specific types of potassium channels in mitochondria, it does suggest that mitochondrial K+ plays a beneficial role in maintaining cellular health.
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Affiliation(s)
| | - Yoshihiro Ohta
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Nakacho, Koganei, Tokyo 184-8588, Japan;
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3
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Rysz S, Fagerlund MJ, Lundberg J, Ringh M, Hollenberg J, Lindgren M, Jonsson M, Djärv T, Nordberg P. The Use of Levosimendan after Out-of-Hospital Cardiac Arrest and Its Association with Outcome-An Observational Study. J Clin Med 2022; 11:jcm11092621. [PMID: 35566747 PMCID: PMC9103888 DOI: 10.3390/jcm11092621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/03/2022] [Accepted: 05/04/2022] [Indexed: 02/06/2023] Open
Abstract
Background: Levosimendan improves resuscitation rates and cardiac performance in animal cardiac arrest models. The aim of this study was to describe the use of levosimendan in out-of-hospital cardiac arrest (OHCA) patients and its association with outcome. Methods: A retrospective observational study of OHCA patients admitted to six intensive care units in Stockholm, Sweden, between 2010 and 2016. Patients treated with levosimendan within 24 h from admission were compared with those not treated with levosimendan. Propensity score matching and multivariable logistic regression analysis were used to assess the association between levosimendan treatment and 30-day mortality Results: Levosimendan treatment was initiated in 94/940 (10%) patients within 24 h. The proportion of men (81%, vs. 67%, p = 0.007), initial shockable rhythm (66% vs. 37%, p < 0.001), acute myocardial infarction, AMI (47% vs. 24%, p < 0.001) and need for vasoactive support (98% vs. 61%, p < 0.001) were higher among patients treated with levosimendan. After adjustment for age, sex, bystander cardiopulmonary resuscitation, witnessed status, initial rhythm and AMI, the odds ratio (OR) for 30-day mortality in the levosimendan group compared to the no-levosimendan group was 0.94 (95% Confidence interval [CI], 0.56−1.57, p = 0.82). Similar results were seen when using a propensity score analysis comparing patients with circulatory shock. Conclusions: In this observational study of OHCA patients, levosimendan was used in a limited patient group, most often in those with initial shockable rhythms, acute myocardial infarction and with a high need for vasopressors. In this limited patient cohort, levosimendan treatment was not associated with 30-day mortality. However, a better matching of patient factors and indications for use is required to derive conclusions on associations with outcome.
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Affiliation(s)
- Susanne Rysz
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76 Stockholm, Sweden; (S.R.); (M.J.F.)
- Department of Medicine Solna, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Malin Jonsson Fagerlund
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76 Stockholm, Sweden; (S.R.); (M.J.F.)
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Johan Lundberg
- Department of Clinical Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
- Department of Neuroradiology, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Mattias Ringh
- Center for Resuscitation Science, Department of Clinical Science and Education, Karolinska Institutet Södersjukhuset, 118 83 Stockholm, Sweden; (M.R.); (J.H.); (M.J.)
| | - Jacob Hollenberg
- Center for Resuscitation Science, Department of Clinical Science and Education, Karolinska Institutet Södersjukhuset, 118 83 Stockholm, Sweden; (M.R.); (J.H.); (M.J.)
| | - Marcus Lindgren
- Department of Medicine, Piteå Hospital, 941 50 Piteå, Sweden;
| | - Martin Jonsson
- Center for Resuscitation Science, Department of Clinical Science and Education, Karolinska Institutet Södersjukhuset, 118 83 Stockholm, Sweden; (M.R.); (J.H.); (M.J.)
| | - Therese Djärv
- Department of Medicine Solna, Karolinska Institutet, 171 77 Stockholm, Sweden;
- Function Emergency Medicine, Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Per Nordberg
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76 Stockholm, Sweden; (S.R.); (M.J.F.)
- Center for Resuscitation Science, Department of Clinical Science and Education, Karolinska Institutet Södersjukhuset, 118 83 Stockholm, Sweden; (M.R.); (J.H.); (M.J.)
- Correspondence:
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4
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González-Sanabria N, Echeverría F, Segura I, Alvarado-Sánchez R, Latorre R. BK in Double-Membrane Organelles: A Biophysical, Pharmacological, and Functional Survey. Front Physiol 2021; 12:761474. [PMID: 34764886 PMCID: PMC8577798 DOI: 10.3389/fphys.2021.761474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 09/29/2021] [Indexed: 12/04/2022] Open
Abstract
In the 1970s, calcium-activated potassium currents were recorded for the first time. In 10years, this Ca2+-activated potassium channel was identified in rat skeletal muscle, chromaffin cells and characterized in skeletal muscle membranes reconstituted in lipid bilayers. This calcium- and voltage-activated potassium channel, dubbed BK for “Big K” due to its large ionic conductance between 130 and 300 pS in symmetric K+. The BK channel is a tetramer where the pore-forming α subunit contains seven transmembrane segments. It has a modular architecture containing a pore domain with a highly potassium-selective filter, a voltage-sensor domain and two intracellular Ca2+ binding sites in the C-terminus. BK is found in the plasma membrane of different cell types, the inner mitochondrial membrane (mitoBK) and the nuclear envelope’s outer membrane (nBK). Like BK channels in the plasma membrane (pmBK), the open probability of mitoBK and nBK channels are regulated by Ca2+ and voltage and modulated by auxiliary subunits. BK channels share common pharmacology to toxins such as iberiotoxin, charybdotoxin, paxilline, and agonists of the benzimidazole family. However, the precise role of mitoBK and nBK remains largely unknown. To date, mitoBK has been reported to play a role in protecting the heart from ischemic injury. At the same time, pharmacology suggests that nBK has a role in regulating nuclear Ca2+, membrane potential and expression of eNOS. Here, we will discuss at the biophysical level the properties and differences of mitoBK and nBK compared to those of pmBK and their pharmacology and function.
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Affiliation(s)
- Naileth González-Sanabria
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Felipe Echeverría
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Ignacio Segura
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Rosangelina Alvarado-Sánchez
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Ramon Latorre
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
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5
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Uryash A, Mijares A, Flores V, Adams JA, Lopez JR. Effects of Naringin on Cardiomyocytes From a Rodent Model of Type 2 Diabetes. Front Pharmacol 2021; 12:719268. [PMID: 34497520 PMCID: PMC8419284 DOI: 10.3389/fphar.2021.719268] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/10/2021] [Indexed: 12/15/2022] Open
Abstract
Diabetic cardiomyopathy (DCM) is a primary disease in diabetic patients characterized by diastolic dysfunction leading to heart failure and death. Unfortunately, even tight glycemic control has not been effective in its prevention. We have found aberrant diastolic Ca2+ concentrations ([Ca2+]d), decreased glucose transport, elevated production of reactive oxygen species (ROS), and increased calpain activity in cardiomyocytes from a murine model (db/db) of type 2 diabetes (T2D). Cardiomyocytes from these mice demonstrate significant cell injury, increased levels of tumor necrosis factor-alpha and interleukin-6 and expression of the transcription nuclear factor-κB (NF-κB). Furthermore, decreased cell viability, and reduced expression of Kir6.2, SUR1, and SUR2 subunits of the ATP-sensitive potassium (KATP) channels. Treatment of T2D mice with the citrus fruit flavonoid naringin for 4 weeks protected cardiomyocytes by reducing diastolic Ca2+ overload, improving glucose transport, lowering reactive oxygen species production, and suppressed myocardial inflammation. In addition, naringin reduced calpain activity, decreased cardiac injury, increased cell viability, and restored the protein expression of Kir6.2, SUR1, and SUR2 subunits of the KATP channels. Administration of the KATP channel inhibitor glibenclamide caused a further increase in [Ca2+]d in T2D cardiomyocytes and abolished the naringin effect on [Ca2+]d. Nicorandil, a KATP channel opener, and nitric oxide donor drug mimic the naringin effect on [Ca2+]d in T2D cardiomyocyte; however, it aggravated the hyperglycemia in T2D mice. These data add new insights into the mechanisms underlying the beneficial effects of naringin in T2D cardiomyopathy, thus suggesting a novel approach to treating this cardiovascular complication.
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Affiliation(s)
- A. Uryash
- Department of Neonatology, Mount Sinai Medical Center, Miami, FL, United States
| | - A. Mijares
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - V. Flores
- Department of Research, Mount Sinai Medical Center, Miami, FL, United States
| | - J. A. Adams
- Department of Neonatology, Mount Sinai Medical Center, Miami, FL, United States
| | - J. R. Lopez
- Department of Research, Mount Sinai Medical Center, Miami, FL, United States
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6
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Flavonoids and Mitochondria: Activation of Cytoprotective Pathways? Molecules 2020; 25:molecules25133060. [PMID: 32635481 PMCID: PMC7412508 DOI: 10.3390/molecules25133060] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023] Open
Abstract
A large number of diverse mechanisms that lead to cytoprotection have been described to date. Perhaps, not surprisingly, the role of mitochondria in these phenomena is notable. In addition to being metabolic centers, due to their role in cell catabolism, ATP synthesis, and biosynthesis these organelles are triggers and/or end-effectors of a large number of signaling pathways. Their role in the regulation of the intrinsic apoptotic pathway, calcium homeostasis, and reactive oxygen species signaling is well documented. In this review, we aim to characterize the prospects of influencing cytoprotective mitochondrial signaling routes by natural substances of plant origin, namely, flavonoids (e.g., flavanones, flavones, flavonols, flavan-3-ols, anthocyanidins, and isoflavones). Flavonoids are a family of widely distributed plant secondary metabolites known for their beneficial effects on human health and are widely applied in traditional medicine. Their pharmacological characteristics include antioxidative, anticarcinogenic, anti-inflammatory, antibacterial, and antidiabetic properties. Here, we focus on presenting mitochondria-mediated cytoprotection against various insults. Thus, the role of flavonoids as antioxidants and modulators of antioxidant cellular response, apoptosis, mitochondrial biogenesis, autophagy, and fission and fusion is reported. Finally, an emerging field of flavonoid-mediated changes in the activity of mitochondrial ion channels and their role in cytoprotection is outlined.
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7
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Signaling pathways targeting mitochondrial potassium channels. Int J Biochem Cell Biol 2020; 125:105792. [PMID: 32574707 DOI: 10.1016/j.biocel.2020.105792] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
Abstract
In this review, we describe key signaling pathways regulating potassium channels present in the inner mitochondrial membrane. The signaling cascades covered here include phosphorylation, redox reactions, modulation by calcium ions and nucleotides. The following types of potassium channels have been identified in the inner mitochondrial membrane of various tissues: ATP-sensitive, Ca2+-activated, voltage-gated and two-pore domain potassium channels. The direct roles of these channels involve regulation of mitochondrial respiration, membrane potential and synthesis of reactive oxygen species (ROS). Changes in channel activity lead to diverse pro-life and pro-death responses in different cell types. Hence, characterizing the signaling pathways regulating mitochondrial potassium channels will facilitate understanding the physiological role of these proteins. Additionally, we describe in this paper certain regulatory mechanisms, which are unique to mitochondrial potassium channels.
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8
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Ge Z, Li A, McNamara J, Dos Remedios C, Lal S. Pathogenesis and pathophysiology of heart failure with reduced ejection fraction: translation to human studies. Heart Fail Rev 2020; 24:743-758. [PMID: 31209771 DOI: 10.1007/s10741-019-09806-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Heart failure represents the end result of different pathophysiologic processes, which culminate in functional impairment. Regardless of its aetiology, the presentation of heart failure usually involves symptoms of pump failure and congestion, which forms the basis for clinical diagnosis. Pathophysiologic descriptions of heart failure with reduced ejection fraction (HFrEF) are being established. Most commonly, HFrEF is centred on a reactive model where a significant initial insult leads to reduced cardiac output, further triggering a cascade of maladaptive processes. Predisposing factors include myocardial injury of any cause, chronically abnormal loading due to hypertension, valvular disease, or tachyarrhythmias. The pathophysiologic processes behind remodelling in heart failure are complex and reflect systemic neurohormonal activation, peripheral vascular effects and localised changes affecting the cardiac substrate. These abnormalities have been the subject of intense research. Much of the translational successes in HFrEF have come from targeting neurohormonal responses to reduced cardiac output, with blockade of the renin-angiotensin-aldosterone system (RAAS) and beta-adrenergic blockade being particularly fruitful. However, mortality and morbidity associated with heart failure remains high. Although systemic neurohormonal blockade slows disease progression, localised ventricular remodelling still adversely affects contractile function. Novel therapy targeted at improving cardiac contractile mechanics in HFrEF hold the promise of alleviating heart failure at its source, yet so far none has found success. Nevertheless, there are increasing calls for a proximal, 'cardiocentric' approach to therapy. In this review, we examine HFrEF therapy aimed at improving cardiac function with a focus on recent trials and emerging targets.
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Affiliation(s)
- Zijun Ge
- Sydney Medical School, University of Sydney, Camperdown, Australia
- Bosch Institute, School of Medical Sciences, University of Sydney, Camperdown, Australia
| | - Amy Li
- Bosch Institute, School of Medical Sciences, University of Sydney, Camperdown, Australia
- Department of Pharmacy and Biomedical Science, La Trobe University, Melbourne, Australia
| | - James McNamara
- Bosch Institute, School of Medical Sciences, University of Sydney, Camperdown, Australia
| | - Cris Dos Remedios
- Bosch Institute, School of Medical Sciences, University of Sydney, Camperdown, Australia
| | - Sean Lal
- Sydney Medical School, University of Sydney, Camperdown, Australia.
- Bosch Institute, School of Medical Sciences, University of Sydney, Camperdown, Australia.
- Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia.
- Cardiac Research Laboratory, Discipline of Anatomy and Histology, University of Sydney, Anderson Stuart Building (F13), Camperdown, NSW, 2006, Australia.
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9
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Rysz S, Lundberg J, Nordberg P, Eriksson H, Wieslander B, Lundin M, Fyrdahl A, Pernow J, Ugander M, Djärv T, Jonsson Fagerlund M. The effect of levosimendan on survival and cardiac performance in an ischemic cardiac arrest model - A blinded randomized placebo-controlled study in swine. Resuscitation 2020; 150:113-120. [PMID: 32234367 DOI: 10.1016/j.resuscitation.2020.02.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/03/2020] [Accepted: 02/27/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Survival after out-of-hospital cardiac arrest remains poor. Levosimendan could be a new intervention in this setting. Therefore, we conducted a blinded, placebo controlled randomized study investigating the effects of levosimendan on survival and cardiac performance in an ischemic cardiac arrest model in swine. METHODS Twenty-four anesthetised swines underwent experimentally-induced acute myocardial infarction and ventricular fibrillation. At the start of CPR, a bolus dose of levosimendan (12 μg kg-1) or placebo was given followed by a 24-h infusion (0.2 μg kg-1 min-1) after return of spontaneously circulation. Animals were evaluated by risk of death, post-resuscitation hemodynamics and infarction size by magnetic resonance imaging (MRI) up to 32 h post arrest. RESULTS Spontaneous circulation was restored in all (12/12) animals in the levosimendan group compared to two thirds (8/12) in the placebo group (P = 0.09). Protocol survival was higher for the levosimendan group (P = 0.02) with an estimated 88% lower risk of death compared to placebo (hazard ratio [95% confidence interval] 0.12 [0.01-0.96], P = 0.046). Cardiac output (CO) recovered 40% faster during the first hour of the intensive care period for the levosimendan group (difference 0.13 [0.01-0.26] L min-1P = 0.04). The placebo group required higher inotropic support during the intensive care period which masked an even bigger recovery in CO in the levosimendan group (58%). The MRI showed no difference in myocardial scar size or in myocardial area at risk. CONCLUSIONS Levosimendan given intra-arrest and during the first 24-h of post-resuscitation care improved survival and cardiac performance in this ischemic cardiac arrest model. Institutional Protocol Number; KERIC 5.2.18-14933.
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Affiliation(s)
- Susanne Rysz
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden; Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
| | - Johan Lundberg
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden
| | - Per Nordberg
- Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Helen Eriksson
- Stockholm University Demography Unit, Department of Sociology, Stockholm University, Sweden
| | - Björn Wieslander
- Department of Clinical Physiology, Karolinska University Hospital, and Karolinska Institutet, Stockholm, Sweden
| | - Magnus Lundin
- Department of Clinical Physiology, Karolinska University Hospital, and Karolinska Institutet, Stockholm, Sweden
| | - Alexander Fyrdahl
- Department of Clinical Physiology, Karolinska University Hospital, and Karolinska Institutet, Stockholm, Sweden
| | - John Pernow
- Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Heart and Vascular Theme, Karolinska University Hospital, Sweden
| | - Martin Ugander
- Department of Clinical Physiology, Karolinska University Hospital, and Karolinska Institutet, Stockholm, Sweden; Kolling Institute, Royal North Shore Hospital, and Northern Clinical School, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Therese Djärv
- Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Function Emergency Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Malin Jonsson Fagerlund
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden; Department of Physiology and Pharmacology, Karolinska Institutet, Sweden
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Oliveira HCF, Vercesi AE. Mitochondrial bioenergetics and redox dysfunctions in hypercholesterolemia and atherosclerosis. Mol Aspects Med 2019; 71:100840. [PMID: 31882067 DOI: 10.1016/j.mam.2019.100840] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 12/12/2022]
Abstract
In the first part of this review, we summarize basic mitochondrial bioenergetics concepts showing that mitochondria are critical regulators of cell life and death. Until a few decades ago, mitochondria were considered to play essential roles only in respiration, ATP formation, non-shivering thermogenesis and a variety of metabolic pathways. However, the concept presented by Peter Mitchell regarding coupling between electron flow and ATP synthesis through the intermediary of a H+ electrochemical potential leads to the recognition that the proton-motive force also regulates a series of relevant cell signalling processes, such as superoxide generation, redox balance and Ca2+ handling. Alterations in these processes lead to cell death and disease states. In the second part of this review, we discuss the role of mitochondrial dysfunctions in the specific context of hypercholesterolemia-induced atherosclerosis. We provide a literature analysis that indicates a decisive role of mitochondrial redox dysfunction in the development of atherosclerosis and discuss the underlying molecular mechanisms. Finally, we highlight the potential mitochondrial-targeted therapeutic strategies that are relevant for atherosclerosis.
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Affiliation(s)
- Helena C F Oliveira
- Department of Structural and Functional Biology, Biology Institute, State University of Campinas, Campinas, SP, Brazil.
| | - Anibal E Vercesi
- Department of Clinical Pathology, Faculty of Medical Sciences, State University of Campinas, Campinas, SP, Brazil.
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11
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Kampa RP, Kicinska A, Jarmuszkiewicz W, Pasikowska-Piwko M, Dolegowska B, Debowska R, Szewczyk A, Bednarczyk P. Naringenin as an opener of mitochondrial potassium channels in dermal fibroblasts. Exp Dermatol 2019; 28:543-550. [PMID: 30776180 DOI: 10.1111/exd.13903] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 02/14/2019] [Indexed: 12/25/2022]
Abstract
Flavonoids belong to a large group of polyphenolic compounds that are widely present in plants. Certain flavonoids, including naringenin, have cytoprotective properties. Although the antioxidant effect has long been thought to be a crucial factor accounting for the cellular effects of flavonoids, mitochondrial channels have emerged recently as targets for cytoprotective strategies. In the present study, we characterized interactions between naringenin and the mitochondrial potassium (mitoBKC a and mitoKATP ) channels recently described in dermal fibroblasts. With the use of the patch-clamp technique and mitoplasts isolated from primary human dermal fibroblast cells, our study shows that naringenin in micromolar concentrations leads to an increase in mitoBKC a channel activity. The opening probability of the channel decreased from 0.97 in the control conditions (200 μmol/L Ca2+ ) to 0.06 at a low Ca2+ level (1 μmol/L) and increased to 0.85 after the application of 10 μmol/L naringenin. Additionally, the activity of the mitoKATP channel increased following the application of 10 μmol/L naringenin. To investigate the effects of naringenin on mitochondrial function, the oxygen consumption of dermal fibroblast cells was measured in potassium-containing media. The addition of naringenin significantly and dose-dependently increased the respiratory rate from 5.8 ± 0.2 to 14.0 ± 0.6 nmol O2 × min-1 × mg protein-1 . Additionally, a Raman spectroscopy analysis of skin penetration indicated that the naringenin was distributed in all skin layers, including the epidermis and dermis. In this study, we demonstrated that a flavonoid, naringenin, can activate two potassium channels present in the inner mitochondrial membrane of dermal fibroblasts.
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Affiliation(s)
- Rafal Pawel Kampa
- Department of Biophysics, Warsaw, University of Life Sciences - SGGW, Warsaw, Poland.,Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw, Poland
| | - Anna Kicinska
- Laboratory of Bioenergetics, Adam Mickiewicz University, Poznan, Poland
| | | | | | - Barbara Dolegowska
- Department of Laboratory Medicine, Pomeranian Medical University, Szczecin, Poland
| | - Renata Debowska
- Dr Irena Eris Cosmetic Laboratory, Center for Science and Research, Piaseczno, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Science, Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Biophysics, Warsaw, University of Life Sciences - SGGW, Warsaw, Poland
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12
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Goswami SK, Ponnalagu D, Hussain AT, Shah K, Karekar P, Gururaja Rao S, Meredith AL, Khan M, Singh H. Expression and Activation of BK Ca Channels in Mice Protects Against Ischemia-Reperfusion Injury of Isolated Hearts by Modulating Mitochondrial Function. Front Cardiovasc Med 2019; 5:194. [PMID: 30746365 PMCID: PMC6360169 DOI: 10.3389/fcvm.2018.00194] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 12/18/2018] [Indexed: 12/14/2022] Open
Abstract
Aims: Activation and expression of large conductance calcium and voltage-activated potassium channel (BKCa) by pharmacological agents have been implicated in cardioprotection from ischemia-reperfusion (IR) injury possibly by regulating mitochondrial function. Given the non-specific effects of pharmacological agents, it is not clear whether activation of BKCa is critical to cardioprotection. In this study, we aimed to decipher the mechanistic role of BKCa in cardioprotection from IR injury by genetically activating BKCa channels. Methods and Results: Hearts from adult (3 months old) wild-type mice (C57/BL6) and mice expressing genetically activated BKCa (Tg-BKCa R207Q, referred as Tg-BKCa) along with wild-type BKCa were subjected to 20 min of ischemia and 30 min of reperfusion with or without ischemic preconditioning (IPC, 2 times for 2.5 min interval each). Left ventricular developed pressure (LVDP) was recorded using Millar's Mikrotip® catheter connected to ADInstrument data acquisition system. Myocardial infarction was quantified by 2,3,5-triphenyl tetrazolium chloride (TTC) staining. Our results demonstrated that Tg-BKCa mice are protected from IR injury, and BKCa also contributes to IPC-mediated cardioprotection. Cardiac function parameters were also measured by echocardiography and no differences were observed in left ventricular ejection fraction, fractional shortening and aortic velocities. Amplex Red® was used to assess reactive oxygen species (ROS) production in isolated mitochondria by spectrofluorometry. We found that genetic activation of BKCa reduces ROS after IR stress. Adult cardiomyocytes and mitochondria from Tg-BKCa mice were isolated and labeled with Anti-BKCa antibodies. Images acquired via confocal microscopy revealed localization of cardiac BKCa in the mitochondria. Conclusions: Activation of BKCa is essential for recovery of cardiac function after IR injury and is likely a factor in IPC mediated cardioprotection. Genetic activation of BKCa reduces ROS produced by complex I and complex II/III in Tg-BKCa mice after IR, and IPC further decreases it. These results implicate BKCa-mediated cardioprotection, in part, by reducing mitochondrial ROS production. Localization of Tg-BKCa in adult cardiomyocytes of transgenic mice was similar to BKCa in wild-type mice.
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Affiliation(s)
- Sumanta Kumar Goswami
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States.,Department of Physiology and Cell Biology, Wexner Medical Center, Ohio State University, Columbus, OH, United States
| | - Devasena Ponnalagu
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States.,Department of Physiology and Cell Biology, Wexner Medical Center, Ohio State University, Columbus, OH, United States
| | - Ahmed T Hussain
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Kajol Shah
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Priyanka Karekar
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States.,Department of Physiology and Cell Biology, Wexner Medical Center, Ohio State University, Columbus, OH, United States
| | - Shubha Gururaja Rao
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States.,Department of Physiology and Cell Biology, Wexner Medical Center, Ohio State University, Columbus, OH, United States
| | - Andrea L Meredith
- Department of Physiology, University of Maryland, Baltimore, MD, United States
| | - Mahmood Khan
- Department of Physiology and Cell Biology, Wexner Medical Center, Ohio State University, Columbus, OH, United States.,Department of Emergency Medicine, Wexner Medical Center, Ohio State University, Columbus, OH, United States
| | - Harpreet Singh
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, United States.,Department of Physiology and Cell Biology, Wexner Medical Center, Ohio State University, Columbus, OH, United States
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13
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Vercesi AE, Castilho RF, Kowaltowski AJ, de Oliveira HCF, de Souza-Pinto NC, Figueira TR, Busanello ENB. Mitochondrial calcium transport and the redox nature of the calcium-induced membrane permeability transition. Free Radic Biol Med 2018; 129:1-24. [PMID: 30172747 DOI: 10.1016/j.freeradbiomed.2018.08.034] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/16/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022]
Abstract
Mitochondria possess a Ca2+ transport system composed of separate Ca2+ influx and efflux pathways. Intramitochondrial Ca2+ concentrations regulate oxidative phosphorylation, required for cell function and survival, and mitochondrial redox balance, that participates in a myriad of signaling and damaging pathways. The interaction between Ca2+ accumulation and redox imbalance regulates opening and closing of a highly regulated inner membrane pore, the membrane permeability transition pore (PTP). In this review, we discuss the regulation of the PTP by mitochondrial oxidants, reactive nitrogen species, and the interactions between these species and other PTP inducers. In addition, we discuss the involvement of mitochondrial redox imbalance and PTP in metabolic conditions such as atherogenesis, diabetes, obesity and in mtDNA stability.
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Affiliation(s)
- Anibal E Vercesi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil.
| | - Roger F Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Helena C F de Oliveira
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, SP, Brazil
| | - Nadja C de Souza-Pinto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Tiago R Figueira
- Escola de Educação Física e Esporte de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Estela N B Busanello
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
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14
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Mitochondrial BK Channel Openers CGS7181 and CGS7184 Exhibit Cytotoxic Properties. Int J Mol Sci 2018; 19:ijms19020353. [PMID: 29370072 PMCID: PMC5855575 DOI: 10.3390/ijms19020353] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 02/08/2023] Open
Abstract
Potassium channel openers (KCOs) have been shown to play a role in cytoprotection through the activation of mitochondrial potassium channels. Recently, in several reports, a number of data has been described as off-target actions for KCOs. In the present study, we investigated the effects of BKCa channel openers CGS7181, CGS7184, NS1619, and NS004 in neuronal cells. For the purpose of this research, we used a rat brain, the mouse hippocampal HT22 cells, and the human astrocytoma U-87 MG cell line. We showed that CGS7184 activated the mitochondrial BKCa (mitoBKCa) channel in single-channel recordings performed on astrocytoma mitoplasts. Moreover, when applied to the rat brain homogenate or isolated rat brain mitochondria, CGS7184 increased the oxygen consumption rate, and can thus be considered a potentially cytoprotective agent. However, experiments on intact neuronal HT22 cells revealed that both CGS7181 and CGS7184 induced HT22 cell death in a concentration- and time-dependent manner. By contrast, we did not observe cell death when NS1619 or NS004 was applied. CGS7184 toxicity was not abolished by BKCa channel inhibitors, suggesting that the observed effects were independent of a BKCa-type channel activity. CGS7184 treatment resulted in an increase of cytoplasmic Ca2+ concentration that likely involved efflux from internal calcium stores and the activation of calpains (calcium-dependent proteases). The cytotoxic effect of the channel opener was partially reversed by a calpain inhibitor. Our data show that KCOs under study not only activate mitoBKCa channels from brain tissue, but also induce cell death when used in cellular models.
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15
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Leaw B, Nair S, Lim R, Thornton C, Mallard C, Hagberg H. Mitochondria, Bioenergetics and Excitotoxicity: New Therapeutic Targets in Perinatal Brain Injury. Front Cell Neurosci 2017; 11:199. [PMID: 28747873 PMCID: PMC5506196 DOI: 10.3389/fncel.2017.00199] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/26/2017] [Indexed: 12/30/2022] Open
Abstract
Injury to the fragile immature brain is implicated in the manifestation of long-term neurological disorders, including childhood disability such as cerebral palsy, learning disability and behavioral disorders. Advancements in perinatal practice and improved care mean the majority of infants suffering from perinatal brain injury will survive, with many subtle clinical symptoms going undiagnosed until later in life. Hypoxic-ischemia is the dominant cause of perinatal brain injury, and constitutes a significant socioeconomic burden to both developed and developing countries. Therapeutic hypothermia is the sole validated clinical intervention to perinatal asphyxia; however it is not always neuroprotective and its utility is limited to developed countries. There is an urgent need to better understand the molecular pathways underlying hypoxic-ischemic injury to identify new therapeutic targets in such a small but critical therapeutic window. Mitochondria are highly implicated following ischemic injury due to their roles as the powerhouse and main energy generators of the cell, as well as cell death processes. While the link between impaired mitochondrial bioenergetics and secondary energy failure following loss of high-energy phosphates is well established after hypoxia-ischemia (HI), there is emerging evidence that the roles of mitochondria in disease extend far beyond this. Indeed, mitochondrial turnover, including processes such as mitochondrial biogenesis, fusion, fission and mitophagy, affect recovery of neurons after injury and mitochondria are involved in the regulation of the innate immune response to inflammation. This review article will explore these mitochondrial pathways, and finally will summarize past and current efforts in targeting these pathways after hypoxic-ischemic injury, as a means of identifying new avenues for clinical intervention.
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Affiliation(s)
- Bryan Leaw
- The Ritchie Centre, Hudson Institute of Medical ResearchClayton, VIC, Australia
| | - Syam Nair
- Perinatal Center, Institute of Physiology and Neuroscience, Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Rebecca Lim
- The Ritchie Centre, Hudson Institute of Medical ResearchClayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University ClaytonClayton, VIC, Australia
| | - Claire Thornton
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' HospitalLondon, United Kingdom
| | - Carina Mallard
- Perinatal Center, Institute of Physiology and Neuroscience, Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Henrik Hagberg
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' HospitalLondon, United Kingdom.,Perinatal Center, Department of Clinical Sciences, Sahlgrenska Academy, Gothenburg UniversityGothenburg, Sweden
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16
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Lee KH, Lee SR, Cho H, Woo JS, Kang JH, Jeong YM, Cheng XW, Kim WS, Kim W. Cardioprotective effects of PKG activation by soluble GC activator, BAY 60-2770, in ischemia-reperfusion-injured rat hearts. PLoS One 2017; 12:e0180207. [PMID: 28671970 PMCID: PMC5495340 DOI: 10.1371/journal.pone.0180207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 06/12/2017] [Indexed: 11/19/2022] Open
Abstract
Soluble guanylate cyclase (sGC) has been suggested as a therapeutic target for cardiac ischemia-reperfusion (IR) injury. Until now, the molecular mechanism of BAY 60-2770, a sGC activator, in cardiac IR injury has not been assessed. To identify the cardioprotective effects of BAY 60-2770 in IR-injured rat hearts, IR injury was established by occlusion of LAD for 40 min and reperfusion for 7 days, and the effects of BAY 60-2770 on myocardial protection were assessed by echocardiography and TTC staining. 5 nM and 5 μM of BAY 60-2770 were perfused into isolated rat hearts in a Langendorff system. After 10- or 30-min reperfusion with BAY 60-2770, cGMP and cAMP concentrations and PKG activation status were examined. Hearts were also perfused with 1 μM KT5823 or 100 μM 5-HD in conjunction with 5 nM Bay 60-2770 to evaluate the protective role of PKG. Mitochondrial oxidative stress was investigated under hypoxia-reoxygenation in H9c2 cells. In IR-injured rat hearts, BAY 60-2770 oral administration reduced infarct size by TTC staining and improved left ventricular function by echocardiography. Tissue samples from BAY 60-2770-perfused hearts had approximately two-fold higher cGMP levels. BAY 60-2770 increased PKG activity in the myocardium, and the reduced infarct area by BAY 60-2770 was abrogated by KT-5823 in isolated myocardium. In H9c2 cardiac myoblasts, hypoxia-reoxygenation-mediated mitochondrial ROS generation was diminished with BAY 60-2770 treatment, but was recovered by pretreatment with KT-5823. BAY 60-2770 demonstrated a protective effect against cardiac IR injury via mitoKATP opening and decreased mitoROS by PKG activation. BAY 60-2770 has a protective effect against cardiac IR injury via mitoKATP opening and decreased mitoROS by PKG activation. These results demonstrated that BAY 60-2770 may be used as a therapeutic agent for cardiac IR injury.
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Affiliation(s)
- Kyung Hye Lee
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - So-Ra Lee
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Haneul Cho
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Jong Shin Woo
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Jung Hee Kang
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Yun-Mi Jeong
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Xian Wu Cheng
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Woo-Shik Kim
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
| | - Weon Kim
- Department of Cardiovascular of Internal Medicine, Kyung Hee University Hospital, Kyung Hee University, Seoul, Republic of Korea
- * E-mail:
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17
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Augustynek B, Kunz WS, Szewczyk A. Guide to the Pharmacology of Mitochondrial Potassium Channels. Handb Exp Pharmacol 2017; 240:103-127. [PMID: 27838853 DOI: 10.1007/164_2016_79] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This chapter provides a critical overview of the available literature on the pharmacology of mitochondrial potassium channels. In the first part, the reader is introduced to the topic, and eight known protein contributors to the potassium permeability of the inner mitochondrial membrane are presented. The main part of this chapter describes the basic characteristics of each channel type mentioned in the introduction. However, the most important and valuable information included in this chapter concerns the pharmacology of mitochondrial potassium channels. Several available channel modulators are critically evaluated and rated by suitability for research use. The last figure of this chapter shows the results of this evaluation at a glance. Thus, this chapter can be very useful for beginners in this field. It is intended to be a time- and resource-saving guide for those searching for proper modulators of mitochondrial potassium channels.
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Affiliation(s)
- Bartłomiej Augustynek
- Laboratory of Intracellular Ion Channels, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Wolfram S Kunz
- Department of Epileptology, University of Bonn, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Department of Biochemistry, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093, Warsaw, Poland.
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18
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Cardiac Slo2.1 Is Required for Volatile Anesthetic Stimulation of K+ Transport and Anesthetic Preconditioning. Anesthesiology 2016; 124:1065-76. [PMID: 26845140 DOI: 10.1097/aln.0000000000001046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Anesthetic preconditioning (APC) is a clinically important phenomenon in which volatile anesthetics (VAs) protect tissues such as heart against ischemic injury. The mechanism of APC is thought to involve K channels encoded by the Slo gene family, and the authors showed previously that slo-2 is required for APC in Caenorhabditis elegans. Thus, the authors hypothesized that a slo-2 ortholog may mediate APC-induced cardioprotection in mammals. METHODS A perfused heart model of ischemia-reperfusion injury, a fluorescent assay for K flux, and mice lacking Slo2.1 (Slick), Slo2.2 (Slack), or both (double knockouts, Slo2.x dKO) were used to test whether these channels are required for APC-induced cardioprotection and for cardiomyocyte or mitochondrial K transport. RESULTS In wild-type (WT) hearts, APC improved post-ischemia-reperfusion functional recovery (APC = 39.5 ± 3.7% of preischemic rate × pressure product vs. 20.3 ± 2.3% in controls, means ± SEM, P = 0.00051, unpaired two-tailed t test, n = 8) and lowered infarct size (APC = 29.0 ± 4.8% of LV area vs. 51.4 ± 4.5% in controls, P = 0.0043, n = 8). Protection by APC was absent in hearts from Slo2.1 mice (% recovery APC = 14.6 ± 2.6% vs. 16.5 ± 2.1% in controls, P = 0.569, n = 8 to 9, infarct APC = 52.2 ± 5.4% vs. 53.5 ± 4.7% in controls, P = 0.865, n = 8 to 9). APC protection was also absent in Slo2.x dKO hearts (% recovery APC = 11.0 ± 1.7% vs. 11.9 ± 2.2% in controls, P = 0.725, n = 8, infarct APC = 51.6 ± 4.4% vs. 50.5 ± 3.9% in controls, P = 0.855, n = 8). Meanwhile, Slo2.2 hearts responded similar to WT (% recovery APC = 41.9 ± 4.0% vs. 18.0 ± 2.5% in controls, P = 0.00016, n = 8, infarct APC = 25.2 ± 1.3% vs. 50.8 ± 3.3% in controls, P < 0.000005, n = 8). Furthermore, VA-stimulated K transport seen in cardiomyocytes or mitochondria from WT or Slo2.2 mice was absent in Slo2.1 or Slo2.x dKO. CONCLUSION Slick (Slo2.1) is required for both VA-stimulated K flux and for the APC-induced cardioprotection.
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19
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Laskowski M, Augustynek B, Kulawiak B, Koprowski P, Bednarczyk P, Jarmuszkiewicz W, Szewczyk A. What do we not know about mitochondrial potassium channels? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1247-1257. [PMID: 26951942 DOI: 10.1016/j.bbabio.2016.03.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 01/14/2023]
Abstract
In this review, we summarize our knowledge about mitochondrial potassium channels, with a special focus on unanswered questions in this field. The following potassium channels have been well described in the inner mitochondrial membrane: ATP-regulated potassium channel, Ca(2+)-activated potassium channel, the voltage-gated Kv1.3 potassium channel, and the two-pore domain TASK-3 potassium channel. The primary functional roles of these channels include regulation of mitochondrial respiration and the alteration of membrane potential. Additionally, they modulate the mitochondrial matrix volume and the synthesis of reactive oxygen species by mitochondria. Mitochondrial potassium channels are believed to contribute to cytoprotection and cell death. In this paper, we discuss fundamental issues concerning mitochondrial potassium channels: their molecular identity, channel pharmacology and functional properties. Attention will be given to the current problems present in our understanding of the nature of mitochondrial potassium channels. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Michał Laskowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Bartłomiej Augustynek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Biophysics, Warsaw University of Life Sciences - SGGW, 159 Nowoursynowska St., 02-776 Warsaw, Poland
| | - Wieslawa Jarmuszkiewicz
- Laboratory of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
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20
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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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21
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Cavalcante FP, Coelho AMM, Machado MCC, Sampietre SN, Patzina RA, Diniz MA, Chaib E, D'Albuquerque LAC. Mechanisms of the beneficial effect of sevoflurane in liver ischemia/reperfusion injury. Acta Cir Bras 2015; 30:749-55. [DOI: 10.1590/s0102-865020150110000005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/19/2015] [Indexed: 11/22/2022] Open
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Abstract
Acute heart failure (AHF) emerges as a major and growing epidemiological concern with high morbidity and mortality rates. Current therapies in patients with acute heart failure rely on different strategies. Patients with hypotension, hypoperfusion, or shock require inotropic support, whereas diuretics and vasodilators are recommended in patients with systemic or pulmonary congestion. Traditionally inotropic agents, referred to as Ca2+ mobilizers load the cardiomyocyte with Ca2+ and thereby increase oxygen consumption and risk for arrhythmias. These limitations of traditional inotropes may be avoided by sarcomere targeted agents. Direct activation of the cardiac sarcomere may be achieved by either sensitizing the cardiac myofilaments to Ca2+ or activating directly the cardiac myosin. In this review, we focus on sarcomere targeted inotropic agents, emphasizing their mechanisms of action and overview the most relevant clinical considerations.
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23
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Li S, Guo J, Ying Z, Chen S, Yang L, Chen K, Long Q, Qin D, Pei D, Liu X. Valproic acid-induced hepatotoxicity in Alpers syndrome is associated with mitochondrial permeability transition pore opening-dependent apoptotic sensitivity in an induced pluripotent stem cell model. Hepatology 2015; 61:1730-9. [PMID: 25605636 DOI: 10.1002/hep.27712] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 01/13/2015] [Indexed: 12/29/2022]
Abstract
UNLABELLED Valproic acid (VPA) is widely used to treat epilepsy, migraine, chronic headache, bipolar disorder, and as adjuvant chemotherapy, but potentially causes idiosyncratic liver injury. Alpers-Huttenlocher syndrome (AHS), a neurometabolic disorder caused by mutations in mitochondrial DNA polymerase gamma (POLG), is associated with an increased risk of developing fatal VPA hepatotoxicity. However, the mechanistic link of this clinical mystery remains unknown. Here, fibroblasts from 2 AHS patients were reprogrammed to induced pluripotent stem cells (iPSCs) and then differentiated to hepatocyte-like cells (AHS iPSCs-Hep). Both AHS iPSCs-Hep are more sensitive to VPA-induced mitochondrial-dependent apoptosis than controls, showing more activated caspase-9 and cytochrome c release. Strikingly, levels of both soluble and oligomeric optic atrophy 1, which together keep cristae junctions tight, are reduced in AHS iPSCs-Hep. Furthermore, POLG mutation cells show reduced POLG expression, mitochondrial DNA (mtDNA) amount, mitochondrial adenosine triphosphate production, as well as abnormal mitochondrial ultrastructure after differentiation to hepatocyte-like cells. Superoxide flashes, spontaneous bursts of superoxide generation, caused by opening of the mitochondrial permeability transition pore (mPTP), occur more frequently in AHS iPSCs-Hep. Moreover, the mPTP inhibitor, cyclosporine A, rescues VPA-induced apoptotic sensitivity in AHS iPSCs-Hep. This result suggests that targeting mPTP opening could be an effective method to prevent hepatotoxicity by VPA in AHS patients. In addition, carnitine or N-acetylcysteine, which has been used in the treatment of VPA-induced hepatotoxicity, is able to rescue VPA-induced apoptotic sensitivity in AHS iPSCs-Hep. CONCLUSION AHS iPSCs-Hep are more sensitive to the VPA-induced mitochondrial-dependent apoptotic pathway, and this effect is mediated by mPTP opening. Toxicity models in genetic diseases using iPSCs enable the evaluation of drugs for therapeutic targets.
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Affiliation(s)
- Shengbiao Li
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China; University of Science and Technology of China, Hefei, Anhui, China
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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: 104] [Impact Index Per Article: 11.6] [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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Agarwal B, Stowe DF, Dash RK, Bosnjak ZJ, Camara AKS. Mitochondrial targets for volatile anesthetics against cardiac ischemia-reperfusion injury. Front Physiol 2014; 5:341. [PMID: 25278902 PMCID: PMC4165278 DOI: 10.3389/fphys.2014.00341] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 08/20/2014] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are critical modulators of cell function and are increasingly recognized as proximal sensors and effectors that ultimately determine the balance between cell survival and cell death. Volatile anesthetics (VA) are long known for their cardioprotective effects, as demonstrated by improved mitochondrial and cellular functions, and by reduced necrotic and apoptotic cell death during cardiac ischemia and reperfusion (IR) injury. The molecular mechanisms by which VA impart cardioprotection are still poorly understood. Because of the emerging role of mitochondria as therapeutic targets in diseases, including ischemic heart disease, it is important to know if VA-induced cytoprotective mechanisms are mediated at the mitochondrial level. In recent years, considerable evidence points to direct effects of VA on mitochondrial channel/transporter protein functions and electron transport chain (ETC) complexes as potential targets in mediating cardioprotection. This review furnishes an integrated overview of targets that VA impart on mitochondrial channels/transporters and ETC proteins that could provide a basis for cation regulation and homeostasis, mitochondrial bioenergetics, and reactive oxygen species (ROS) emission in redox signaling for cardiac cell protection during IR injury.
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Affiliation(s)
- Bhawana Agarwal
- Department of Anesthesiology, Medical College of WisconsinMilwaukee, WI, USA
| | - David F. Stowe
- Department of Anesthesiology, Medical College of WisconsinMilwaukee, WI, USA
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA
- Cardiovascular Research Center, Medical College of WisconsinMilwaukee, WI, USA
- Zablocki VA Medical CenterMilwaukee, WI, USA
- Department of Biomedical Engineering, Marquette UniversityMilwaukee, WI, USA
| | - Ranjan K. Dash
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA
- Department of Biomedical Engineering, Marquette UniversityMilwaukee, WI, USA
- Biotechnology and Bioengineering Center, Medical College of WisconsinMilwaukee, WI, USA
| | - Zeljko J. Bosnjak
- Department of Anesthesiology, Medical College of WisconsinMilwaukee, WI, USA
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA
- Cardiovascular Research Center, Medical College of WisconsinMilwaukee, WI, USA
| | - Amadou K. S. Camara
- Department of Anesthesiology, Medical College of WisconsinMilwaukee, WI, USA
- Cardiovascular Research Center, Medical College of WisconsinMilwaukee, WI, USA
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Augustynek B, Kudin AP, Bednarczyk P, Szewczyk A, Kunz WS. Hemin inhibits the large conductance potassium channel in brain mitochondria: A putative novel mechanism of neurodegeneration. Exp Neurol 2014; 257:70-5. [DOI: 10.1016/j.expneurol.2014.04.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 04/14/2014] [Accepted: 04/23/2014] [Indexed: 02/05/2023]
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Abstract
The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information.
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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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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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Pereira SP, Pereira GC, Pereira CV, Carvalho FS, Cordeiro MH, Mota PC, Ramalho-Santos J, Moreno AJ, Oliveira PJ. Dioxin-induced acute cardiac mitochondrial oxidative damage and increased activity of ATP-sensitive potassium channels in Wistar rats. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 180:281-290. [PMID: 23796802 DOI: 10.1016/j.envpol.2013.05.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 05/25/2013] [Accepted: 05/29/2013] [Indexed: 06/02/2023]
Abstract
The environmental dioxin 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is classified as a Group 1 human carcinogen and teratogenic agent. We hypothesize that TCDD-induced oxidative stress may also interfere with mitochondrial ATP-sensitive potassium channels (mitoKATP), which are known to regulate and to be regulated by mitochondrial redox state. We investigated the effects of an acute treatment of male Wistar rats with TCDD (50 μg/kg i.p.) and measured the regulation of cardiac mitoKATP. While the function of cardiac mitochondria was slightly depressed, mitoKATP activity was 52% higher in animals treated with TCDD. The same effects were not observed in liver mitochondria isolated from the same animals. Our data also shows that regulation of mitochondrial ROS production by mitoKATP activity is different in both groups. To our knowledge, this is the first report to show that TCDD increases mitoKATP activity in the heart, which may counteract the increased oxidative stress caused by the dioxin during acute exposure.
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Affiliation(s)
- Susana P Pereira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês de Pombal, 3004-517 Coimbra, Portugal.
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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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Alberici LC, Paim BA, Zecchin KG, Mirandola SR, Pestana CR, Castilho RF, Vercesi AE, Oliveira HCF. Activation of the mitochondrial ATP-sensitive K+ channel reduces apoptosis of spleen mononuclear cells induced by hyperlipidemia. Lipids Health Dis 2013; 12:87. [PMID: 23764148 PMCID: PMC3693968 DOI: 10.1186/1476-511x-12-87] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 06/10/2013] [Indexed: 01/09/2023] Open
Abstract
Background We have previously demonstrated that increased rates of superoxide generation by extra-mitochondrial enzymes induce the activation of the mitochondrial ATP-sensitive potassium channel (mitoKATP) in the livers of hypertriglyceridemic (HTG) mice. The resulting mild uncoupling mediated by mitoKATP protects mitochondria against oxidative damage. In this study, we investigate whether immune cells from HTG mice also present increased mitoKATP activity and evaluate the influence of this trait on cell redox state and viability. Methods Oxygen consumption (Clark-type electrode), reactive oxygen species production (dihydroethidium and H2-DCF-DA probes) and cell death (annexin V, cytocrome c release and Trypan blue exclusion) were determined in spleen mononuclear cells. Results HTG mice mononuclear cells displayed increased mitoKATP activity, as evidenced by higher resting respiration rates that were sensitive to mitoKATP antagonists. Whole cell superoxide production and apoptosis rates were increased in HTG cells. Inhibition of mitoKATP further increased the production of reactive oxygen species and apoptosis in these cells. Incubation with HTG serum induced apoptosis more strongly in WT cells than in HTG mononuclear cells. Cytochrome c release into the cytosol and caspase 8 activity were both increased in HTG cells, indicating that cell death signaling starts upstream of the mitochondria but does involve this organelle. Accordingly, a reduced number of blood circulating lymphocytes was found in HTG mice. Conclusions These results demonstrate that spleen mononuclear cells from hyperlipidemic mice have more active mitoKATP channels, which downregulate mitochondrial superoxide generation. The increased apoptosis rate observed in these cells is exacerbated by closing the mitoKATP channels. Thus, mitoKATP opening acts as a protective mechanism that reduces cell death induced by hyperlipidemia.
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Affiliation(s)
- Luciane C Alberici
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
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Figueira TR, Barros MH, Camargo AA, Castilho RF, Ferreira JCB, Kowaltowski AJ, Sluse FE, Souza-Pinto NC, Vercesi AE. Mitochondria as a source of reactive oxygen and nitrogen species: from molecular mechanisms to human health. Antioxid Redox Signal 2013; 18:2029-74. [PMID: 23244576 DOI: 10.1089/ars.2012.4729] [Citation(s) in RCA: 304] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mitochondrially generated reactive oxygen species are involved in a myriad of signaling and damaging pathways in different tissues. In addition, mitochondria are an important target of reactive oxygen and nitrogen species. Here, we discuss basic mechanisms of mitochondrial oxidant generation and removal and the main factors affecting mitochondrial redox balance. We also discuss the interaction between mitochondrial reactive oxygen and nitrogen species, and the involvement of these oxidants in mitochondrial diseases, cancer, neurological, and cardiovascular disorders.
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Affiliation(s)
- Tiago R Figueira
- Department of Clinical Pathology, Faculty of Medical Sciences, State University of Campinas, Campinas, Brazil
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Grattagliano I, Diogo CV, Mastrodonato M, de Bari O, Persichella M, Wang DQH, Liquori A, Ferri D, Carratù MR, Oliveira PJ, Portincasa P. A silybin-phospholipids complex counteracts rat fatty liver degeneration and mitochondrial oxidative changes. World J Gastroenterol 2013; 19:3007-3017. [PMID: 23716980 PMCID: PMC3662940 DOI: 10.3748/wjg.v19.i20.3007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 10/22/2012] [Accepted: 11/13/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effectiveness of antioxidant compounds in modulating mitochondrial oxidative alterations and lipids accumulation in fatty hepatocytes.
METHODS: Silybin-phospholipid complex containing vitamin E (Realsil®) was daily administered by gavage (one pouch diluted in 3 mL of water and containing 15 mg vitamin E and 47 mg silybin complexed with phospholipids) to rats fed a choline-deprived (CD) or a high fat diet [20% fat, containing 71% total calories as fat, 11% as carbohydrate, and 18% as protein, high fat diet (HFD)] for 30 d and 60 d, respectively. The control group was fed a normal semi-purified diet containing adequate levels of choline (35% total calories as fat, 47% as carbohydrate, and 18% as protein). Circulating and hepatic redox active and nitrogen regulating molecules (thioredoxin, glutathione, glutathione peroxidase), NO metabolites (nitrosothiols, nitrotyrosine), lipid peroxides [malondialdehyde-thiobarbituric (MDA-TBA)], and pro-inflammatory keratins (K-18) were measured on days 0, 7, 14, 30, and 60. Mitochondrial respiratory chain proteins and the extent of hepatic fatty infiltration were evaluated.
RESULTS: Both diet regimens produced liver steatosis (50% and 25% of liver slices with CD and HFD, respectively) with no signs of necro-inflammation: fat infiltration ranged from large droplets at day 14 to disseminated and confluent vacuoles resulting in microvesicular steatosis at day 30 (CD) and day 60 (HFD). In plasma, thioredoxin and nitrosothiols were not significantly changed, while MDA-TBA, nitrotyrosine (from 6 ± 1 nmol/L to 14 ± 3 nmol/L day 30 CD, P < 0.001, and 12 ± 2 nmol/L day 60 HFD, P < 0.001), and K-18 (from 198 ± 20 to 289 ± 21 U/L day 30 CD, P < 0.001, and 242 ± 23 U/L day 60 HFD, P < 0.001) levels increased significantly with ongoing steatosis. In the liver, glutathione was decreased (from 34.0 ± 1.3 to 25.3 ± 1.2 nmol/mg prot day 30 CD, P < 0.001, and 22.4 ± 2.4 nmol/mg prot day 60 HFD, P < 0.001), while thioredoxin and glutathione peroxidase were initially increased and then decreased. Nitrosothiols were constantly increased. MDA-TBA levels were five-fold increased from 9.1 ± 1.2 nmol/g to 75.6 ± 5.4 nmol/g on day 30, P < 0.001 (CD) and doubled with HFD on day 60. Realsil administration significantly lowered the extent of fat infiltration, maintained liver glutathione levels during the first half period, and halved its decrease during the second half. Also, Realsil modulated thioredoxin changes and the production of NO derivatives and significantly lowered MDA-TBA levels both in liver (from 73.6 ± 5.4 to 57.2 ± 6.3 nmol/g day 30 CD, P < 0.01 and from 27.3 ± 2.1 nmol/g to 20.5 ± 2.2 nmol/g day 60 HFD, P < 0.01) and in plasma. Changes in mitochondrial respiratory complexes were also attenuated by Realsil in HFD rats with a major protective effect on Complex II subunit CII-30.
CONCLUSION: Realsil administration effectively contrasts hepatocyte fat deposition, NO derivatives formation, and mitochondrial alterations, allowing the liver to maintain a better glutathione and thioredoxin antioxidant activity.
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Pathak A, Lebrin M, Vaccaro A, Senard JM, Despas F. Pharmacology of levosimendan: inotropic, vasodilatory and cardioprotective effects. J Clin Pharm Ther 2013; 38:341-9. [PMID: 23594161 DOI: 10.1111/jcpt.12067] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 03/20/2013] [Indexed: 01/15/2023]
Abstract
WHAT IS KNOWN AND OBJECTIVE Positive inotropic agents are frequently used in acute decompensated heart failure (ADHF) due to left ventricular systolic dysfunction. These agents are known to improve cardiac performance and peripheral perfusion in the short-term treatment. However, several preclinical and clinical studies emphasized detrimental effects of these drugs on myocardial oxygen demand and on sympathetic tone entailing arrhythmogenesis. Levosimendan is an inotropic agent with an original mechanism of action. This review focuses on major data available for levosimendan. METHODS A literature search was conducted in the PubMed database by including studies published in English using combinations of the following key words, levosimendan, inotropic drugs and acute heart failure. Furthermore, bibliographies of selected references were also evaluated for relevant articles. The collection for this review was limited to the most recently available human and animal data. RESULTS AND DISCUSSION Levosimendan's vasodilatory and cardioprotective effects are mediated by calcium sensitization of contractile proteins and opening of adenosine triphosphate (ATP)-dependent K+ channels in vascular smooth muscle cells and on mitochondrial ATP-sensitive potassium [mito.K(ATP)] channels. This inotropic agent has mild PDE inhibitory action. Unlike other inotropic agents, levosimendan improves cardiac performance without activating the sympathetic nervous system. Moreover, there are evidences that levosimendan has additional anti-inflammatory and anti-apoptotic properties that prevent cardiac toxicity and contributes to positive hemodynamic response of the drug. Four randomized trials evaluated the effects of levosimendan on mortality in patients with acute decompensated chronic heart failure; nevertheless, a clear benefit has not been demonstrated so far. Although levosimendan is indicated for the treatment of ADHF (class of recommendation IIa, level of evidence B), it is has not been approved in all countries. WHAT IS NEW AND CONCLUSION This review summarizes the characteristics and the current knowledge of the literature on levosimendan and its active metabolite OR-1896.
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Affiliation(s)
- A Pathak
- Institut National de Sante et de Recherche Médicale (INSERM), UMR-1048, Institut des maladies métaboliques et cardiovasculaires I2MC, Toulouse, France
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Wojtovich AP, Urciuoli WR, Chatterjee S, Fisher AB, Nehrke K, Brookes PS. Kir6.2 is not the mitochondrial KATP channel but is required for cardioprotection by ischemic preconditioning. Am J Physiol Heart Circ Physiol 2013; 304:H1439-45. [PMID: 23585131 DOI: 10.1152/ajpheart.00972.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
ATP-sensitive K(+) (KATP) channels that contain K(+) inward rectifier subunits of the 6.2 isotype (Kir6.2) are important regulators of the cardiac response to ischemia-reperfusion (I/R) injury. Opening of these channels is implicated in the cardioprotective mechanism of ischemic preconditioning (IPC), but debate surrounds the contribution of surface KATP (sKATP) versus mitochondrial KATP (mKATP) channels. While responses to I/R injury and IPC have been examined in Kir6.2(-/-) mice before, breeding methods and other technical obstacles may have confounded interpretations. The aim of this study was to elucidate the role of Kir6.2 in cardioprotection and mKATP activity, using conventionally bred Kir6.2(-/-) mice with wild-type littermates as controls. We found that perfused hearts from Kir6.2(-/-) mice exhibited a normal baseline response to I/R injury, were not protected by IPC, and showed a blunted response to the IPC mimetic drug diazoxide. These data suggest that the loss of IPC in Kir6.2(-/-) hearts is not due to an underlying difference in I/R sensitivity. Furthermore, mKATP channel activity was identical in cardiac mitochondria isolated from wild-type versus Kir6.2(-/-) mice, suggesting no role for Kir6.2 in the mKATP. Collectively, these data indicate that Kir6.2 is required for the full response to IPC or diazoxide but is not involved in mKATP formation.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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Bednarczyk P, Koziel A, Jarmuszkiewicz W, Szewczyk A. Large-conductance Ca²⁺-activated potassium channel in mitochondria of endothelial EA.hy926 cells. Am J Physiol Heart Circ Physiol 2013; 304:H1415-27. [PMID: 23542921 DOI: 10.1152/ajpheart.00976.2012] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the present study, we describe the existence of a large-conductance Ca²⁺-activated potassium (BKCa) channel in the mitochondria of the human endothelial cell line EA.hy926. A single-channel current was recorded from endothelial mitoplasts (i.e., inner mitochondrial membrane) using the patch-clamp technique in the mitoplast-attached mode. A potassium-selective current was recorded with a mean conductance equal to 270 ± 10 pS in a symmetrical 150/150 mM KCl isotonic solution. The channel activity, which was determined as the open probability, increased with the addition of calcium ions and the potassium channel opener NS1619. Conversely, the activity of the channel was irreversibly blocked by paxilline and iberiotoxin, BKCa channel inhibitors. The open-state probability was found to be voltage dependent. The substances known to modulate BKCa channel activity influenced the bioenergetics of mitochondria isolated from human endothelial EA.hy926 cells. In isolated mitochondria, 100 μM Ca²⁺, 10 μM NS1619, and 0.5 μM NS11021 depolarized the mitochondrial membrane potential and stimulated nonphosphorylating respiration. These effects were blocked by iberiotoxin and paxilline in a potassium-dependent manner. Under phosphorylating conditions, NS1619-induced, iberiotoxin-sensitive uncoupling diverted energy from ATP synthesis during the phosphorylating respiration of the endothelial mitochondria. Immunological analysis with antibodies raised against proteins of the plasma membrane BKCa channel identified a pore-forming α-subunit and an auxiliary β₂-subunit of the channel in the endothelial mitochondrial inner membrane. In conclusion, we show for the first time that the inner mitochondrial membrane in human endothelial EA.hy926 cells contains a large-conductance calcium-dependent potassium channel with properties similar to those of the surface membrane BKCa channel.
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Affiliation(s)
- Piotr Bednarczyk
- Department of Biophysics, Warsaw University of Life Sciences, Warsaw, Poland
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Wojtovich AP, Nadtochiy SM, Urciuoli WR, Smith CO, Grunnet M, Nehrke K, Brookes PS. A non-cardiomyocyte autonomous mechanism of cardioprotection involving the SLO1 BK channel. PeerJ 2013; 1:e48. [PMID: 23638385 PMCID: PMC3628382 DOI: 10.7717/peerj.48] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 02/19/2013] [Indexed: 12/30/2022] Open
Abstract
Opening of BK-type Ca2+ activated K+ channels protects the heart against ischemia-reperfusion (IR) injury. However, the location of BK channels responsible for cardioprotection is debated. Herein we confirmed that openers of the SLO1 BK channel, NS1619 and NS11021, were protective in a mouse perfused heart model of IR injury. As anticipated, deletion of the Slo1 gene blocked this protection. However, in an isolated cardiomyocyte model of IR injury, protection by NS1619 and NS11021 was insensitive to Slo1 deletion. These data suggest that protection in intact hearts occurs by a non-cardiomyocyte autonomous, SLO1-dependent, mechanism. In this regard, an in-situ assay of intrinsic cardiac neuronal function (tachycardic response to nicotine) revealed that NS1619 preserved cardiac neurons following IR injury. Furthermore, blockade of synaptic transmission by hexamethonium suppressed cardioprotection by NS1619 in intact hearts. These results suggest that opening SLO1 protects the heart during IR injury, via a mechanism that involves intrinsic cardiac neurons. Cardiac neuronal ion channels may be useful therapeutic targets for eliciting cardioprotection.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Medicine, University of Rochester Medical Center , Rochester, NY , USA
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39
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Akopova OV. The effect of potential-dependent potassium uptake on membrane potential in rat brain mitochondria. UKRAINIAN BIOCHEMICAL JOURNAL 2013. [DOI: 10.15407/ubj85.01.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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40
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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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Wojtovich AP, Smith CO, Haynes CM, Nehrke KW, Brookes PS. Physiological consequences of complex II inhibition for aging, disease, and the mKATP channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:598-611. [PMID: 23291191 DOI: 10.1016/j.bbabio.2012.12.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 12/14/2012] [Accepted: 12/17/2012] [Indexed: 12/21/2022]
Abstract
In recent years, it has become apparent that there exist several roles for respiratory complex II beyond metabolism. These include: (i) succinate signaling, (ii) reactive oxygen species (ROS) generation, (iii) ischemic preconditioning, (iv) various disease states and aging, and (v) a role in the function of the mitochondrial ATP-sensitive K(+) (mKATP) channel. This review will address the involvement of complex II in each of these areas, with a focus on how complex II regulates or may be involved in the assembly of the mKATP. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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Papp Z, Édes I, Fruhwald S, De Hert SG, Salmenperä M, Leppikangas H, Mebazaa A, Landoni G, Grossini E, Caimmi P, Morelli A, Guarracino F, Schwinger RH, Meyer S, Algotsson L, Wikström BG, Jörgensen K, Filippatos G, Parissis JT, González MJG, Parkhomenko A, Yilmaz MB, Kivikko M, Pollesello P, Follath F. Levosimendan: Molecular mechanisms and clinical implications. Int J Cardiol 2012; 159:82-7. [DOI: 10.1016/j.ijcard.2011.07.022] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 07/01/2011] [Accepted: 07/03/2011] [Indexed: 11/28/2022]
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Wojtovich AP, DiStefano P, Sherman T, Brookes PS, Nehrke K. Mitochondrial ATP-sensitive potassium channel activity and hypoxic preconditioning are independent of an inwardly rectifying potassium channel subunit in Caenorhabditis elegans. FEBS Lett 2012; 586:428-34. [PMID: 22281198 DOI: 10.1016/j.febslet.2012.01.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 01/12/2012] [Accepted: 01/13/2012] [Indexed: 12/22/2022]
Abstract
Hypoxic preconditioning (HP) is an evolutionarily-conserved mechanism that protects an organism against stress. The mitochondrial ATP-sensitive K(+) channel (mK(ATP)) plays an essential role in the protective signaling, but remains molecularly undefined. Several lines of evidence suggest that mK(ATP) may arise from an inward rectifying K(+) channel (Kir). The genetic model organism Caenorhabditis elegans exhibits HP and displays mK(ATP) activity. Here, we investigate the tissue expression profile of the three C. elegans Kir genes and demonstrate that mutant strains where the irk genes have been deleted either individually or in combination can be protected by HP and exhibit robust mK(ATP) channel activity in purified mitochondria. These data suggest that the mK(ATP) in C. elegans does not arise from a Kir derived channel.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA
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Wojtovich AP, Sherman TA, Nadtochiy SM, Urciuoli WR, Brookes PS, Nehrke K. SLO-2 is cytoprotective and contributes to mitochondrial potassium transport. PLoS One 2011; 6:e28287. [PMID: 22145034 PMCID: PMC3228735 DOI: 10.1371/journal.pone.0028287] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/04/2011] [Indexed: 11/19/2022] Open
Abstract
Mitochondrial potassium channels are important mediators of cell protection against stress. The mitochondrial large-conductance "big" K(+) channel (mBK) mediates the evolutionarily-conserved process of anesthetic preconditioning (APC), wherein exposure to volatile anesthetics initiates protection against ischemic injury. Despite the role of the mBK in cardioprotection, the molecular identity of the channel remains unknown. We investigated the attributes of the mBK using C. elegans and mouse genetic models coupled with measurements of mitochondrial K(+) transport and APC. The canonical Ca(2+)-activated BK (or "maxi-K") channel SLO1 was dispensable for both mitochondrial K(+) transport and APC in both organisms. Instead, we found that the related but physiologically-distinct K(+) channel SLO2 was required, and that SLO2-dependent mitochondrial K(+) transport was triggered directly by volatile anesthetics. In addition, a SLO2 channel activator mimicked the protective effects of volatile anesthetics. These findings suggest that SLO2 contributes to protection from hypoxic injury by increasing the permeability of the mitochondrial inner membrane to K(+).
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Affiliation(s)
- Andrew P. Wojtovich
- Department of Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Teresa A. Sherman
- Department of Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Sergiy M. Nadtochiy
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - William R. Urciuoli
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Paul S. Brookes
- Department of Anesthesiology, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Keith Nehrke
- Department of Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
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Szabò I, Leanza L, Gulbins E, Zoratti M. Physiology of potassium channels in the inner membrane of mitochondria. Pflugers Arch 2011; 463:231-46. [PMID: 22089812 DOI: 10.1007/s00424-011-1058-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 10/30/2011] [Indexed: 02/06/2023]
Abstract
The inner membrane of the ATP-producing organelles of endosymbiotic origin, mitochondria, has long been considered to be poorly permeable to cations and anions, since the strict control of inner mitochondrial membrane permeability is crucial for efficient ATP synthesis. Over the past 30 years, however, it has become clear that various ion channels--along with antiporters and uniporters--are present in the mitochondrial inner membrane, although at rather low abundance. These channels are important for energy supply, and some are a decisive factor in determining whether a cell lives or dies. Their electrophysiological and pharmacological characterisations have contributed importantly to the ongoing elucidation of their pathophysiological roles. This review gives an overview of recent advances in our understanding of the functions of the mitochondrial potassium channels identified so far. Open issues concerning the possible molecular entities giving rise to the observed activities and channel protein targeting to mitochondria are also discussed.
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Affiliation(s)
- Ildikò Szabò
- Department of Biology, University of Padova, Padova, Italy.
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Ischemic preconditioning: the role of mitochondria and aging. Exp Gerontol 2011; 47:1-7. [PMID: 22100642 DOI: 10.1016/j.exger.2011.11.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/24/2011] [Accepted: 11/02/2011] [Indexed: 11/22/2022]
Abstract
Aging represents a triple threat for myocardial infarction (MI). Not only does the incidence of MI increase with age, but the heart becomes more susceptible to MI induced damage and protective interventions such as ischemic preconditioning (IPC) become less effective. Therefore, any rational therapeutic strategy must be built around the ability to combat the detrimental effects of ischemia in aged individuals. To accomplish this, we need to develop a better understanding of how ischemic damage, protection, and aging are linked. In this regard, mitochondria have emerged as a common theme. First, mitochondria contribute to cell damage during ischemia-reperfusion (IR) and are central to cell death. Second, the protective signaling pathways activated by IPC converge on mitochondria, and the opening of mitochondrial ion channels alone is sufficient to elicit protection. Finally, mitochondria clearly influence the aging process, and specific defects in mitochondrial activity are associated with age-related functional decline. This review will summarize the effects of aging on myocardial IR injury and discuss relevant and emerging strategies to protect against MI with an emphasis on mitochondrial function.
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Akopova OV, Nosar VI, Bouryi VA, Mankovskaya IN, Sagach VF. Influence of ATP-dependent K(+)-channel opener on K(+)-cycle and oxygen consumption in rat liver mitochondria. BIOCHEMISTRY (MOSCOW) 2011; 75:1139-47. [PMID: 21077833 DOI: 10.1134/s0006297910090075] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The influence of the K+(ATP)-channel opener diazoxide on the K+ cycle and oxygen consumption has been studied in rat liver mitochondria. It was found that diazoxide activates the K+(ATP)-channel in the range of nanomolar concentrations (50-300 nM, K(1/2) ~ 140 nM), which results in activation of K+/H+ exchange in mitochondria. The latter, in turn, accelerates mitochondrial respiration in respiratory state 2. The contribution of K+(ATP)-channel to the mitochondrial potassium cycle was estimated using the selective K+(ATP)-channel blocker glibenclamide. The data show that the relative contribution of K+(ATP)-channel in the potassium cycle of mitochondria is variable and increases only with the decrease in the ATP-independent component of K+ uptake. Possible mechanisms underlying the observed phenomena are discussed. The experimental results more fully elucidate the role of K+(ATP)-channel in the regulation of mitochondrial functions, especially under pathological conditions accompanied by impairment of the mitochondrial energy state.
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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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Rapposelli S. Novel adenosine 5'-triphosphate-sensitive potassium channel ligands: a patent overview (2005-2010). Expert Opin Ther Pat 2011; 21:355-79. [PMID: 21269236 DOI: 10.1517/13543776.2011.553601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION ATP-sensitive potassium channels are important metabolic regulators that link cellular metabolism to excitability. Their wide distribution in various tissues and organs makes them significant and topical targets in a large number of diseases. AREAS COVERED This review summarizes the current understanding of the molecular biology and pharmacology of K(ATP) channels, and the pathological states that result from aberrant expression or function of these proteins. In particular, relevant research, patents and patent applications of the past 5 years are discussed. EXPERT OPINION The tissue-specific K(ATP) channel modulation reflects an early discovery stage in drug design. The wide distribution of K(ATP) channels lets us consider them as valid targets for several pathologies, but on other hand the ubiquitous nature is a relevant drawback in developing an effective therapy because of the onset of side effects related to the lack of selectivity. On this basis, further investigations on both the structures and the localization of each receptor subtype should be carried out either exploring the structure-activity relationship of the already existing K(ATP) ligands or developing new selective fluorescent probes. To date, this research area still strives to design new tissue-targeted ligands that could pave the way to the development of innovative and effective drugs for clinical use.
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Affiliation(s)
- Simona Rapposelli
- Dipartimento di Scienze Farmaceutiche - Università di Pisa, Via Bonanno, 6, 56126 Pisa, Italy.
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Queliconi BB, Wojtovich AP, Nadtochiy SM, Kowaltowski AJ, Brookes PS. Redox regulation of the mitochondrial K(ATP) channel in cardioprotection. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1309-15. [PMID: 21094666 DOI: 10.1016/j.bbamcr.2010.11.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 10/05/2010] [Accepted: 11/11/2010] [Indexed: 12/12/2022]
Abstract
The mitochondrial ATP-sensitive potassium channel (mK(ATP)) is important in the protective mechanism of ischemic preconditioning (IPC). The channel is reportedly sensitive to reactive oxygen and nitrogen species, and the aim of this study was to compare such species in parallel, to build a more comprehensive picture of mK(ATP) regulation. mK(ATP) activity was measured by both osmotic swelling and Tl(+) flux assays, in isolated rat heart mitochondria. An isolated adult rat cardiomyocyte model of ischemia-reperfusion (IR) injury was also used to determine the role of mK(ATP) in cardioprotection by nitroxyl. Key findings were as follows: (i) mK(ATP) was activated by O(2)(-) and H(2)O(2) but not other peroxides. (ii) mK(ATP) was inhibited by NADPH. (iii) mK(ATP) was activated by S-nitrosothiols, nitroxyl, and nitrolinoleate. The latter two species also inhibited mitochondrial complex II. (iv) Nitroxyl protected cardiomyocytes against IR injury in an mK(ATP)-dependent manner. Overall, these results suggest that the mK(ATP) channel is activated by specific reactive oxygen and nitrogen species, and inhibited by NADPH. The redox modulation of mK(ATP) may be an underlying mechanism for its regulation in the context of IPC. This article is part of a Special Issue entitled: Mitochondria and Cardioprotection.
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Affiliation(s)
- Bruno B Queliconi
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
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Cavalheiro RA, Marin RM, Rocco SA, Cerqueira FM, Caldeira da Silva CC, Rittner R, Kowaltowski AJ, Vercesi AE, Franchini KG, Castilho RF. Potent cardioprotective effect of the 4-anilinoquinazoline derivative PD153035: involvement of mitochondrial K(ATP) channel activation. PLoS One 2010; 5:e10666. [PMID: 20498724 PMCID: PMC2871796 DOI: 10.1371/journal.pone.0010666] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Accepted: 04/27/2010] [Indexed: 11/21/2022] Open
Abstract
Background The aim of the present study was to evaluate the protective effects of the 4-anilinoquinazoline derivative PD153035 on cardiac ischemia/reperfusion and mitochondrial function. Methodology/Principal Findings Perfused rat hearts and cardiac HL-1 cells were used to determine cardioprotective effects of PD153035. Isolated rat heart mitochondria were studied to uncover mechanisms of cardioprotection. Nanomolar doses of PD153035 strongly protect against heart and cardiomyocyte damage induced by ischemia/reperfusion and cyanide/aglycemia. PD153035 did not alter oxidative phosphorylation, nor directly prevent Ca2+ induced mitochondrial membrane permeability transition. The protective effect of PD153035 on HL-1 cells was also independent of AKT phosphorylation state. Interestingly, PD153035 activated K+ transport in isolated mitochondria, in a manner prevented by ATP and 5-hydroxydecanoate, inhibitors of mitochondrial ATP-sensitive K+ channels (mitoKATP). 5-Hydroxydecanoate also inhibited the cardioprotective effect of PD153035 in cardiac HL-1 cells, demonstrating that this protection is dependent on mitoKATP activation. Conclusions/Significance We conclude that PD153035 is a potent cardioprotective compound and acts in a mechanism involving mitoKATP activation.
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Affiliation(s)
- Renata A. Cavalheiro
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Rodrigo M. Marin
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Silvana A. Rocco
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Fernanda M. Cerqueira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | | | - Roberto Rittner
- Departamento de Química Orgânica, Instituto de Química, Universidade Estadual de Campinas, Campinas, Brazil
| | - Alicia J. Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Anibal E. Vercesi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
| | - Kleber G. Franchini
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
- * E-mail: (RFC); (KGF)
| | - Roger F. Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
- * E-mail: (RFC); (KGF)
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