1
|
Szewczyk A. Understanding mitochondrial potassium channels: 33 years after discovery. Acta Biochim Pol 2024; 71:13126. [PMID: 38863652 PMCID: PMC11165062 DOI: 10.3389/abp.2024.13126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Accepted: 05/20/2024] [Indexed: 06/13/2024]
Abstract
Mitochondrial investigations have extended beyond their traditional functions, covering areas such as ATP synthesis and metabolism. Mitochondria are now implicated in new functional areas such as cytoprotection, cellular senescence, tumor function and inflammation. The basis of these new areas still relies on fundamental biochemical/biophysical mitochondrial functions such as synthesis of reactive oxygen species, mitochondrial membrane potential, and the integrity of the inner mitochondrial membrane i.e., the passage of various molecules through the mitochondrial membranes. In this view transport of potassium cations, known as the potassium cycle, plays an important role. It is believed that K+ influx is mediated by various potassium channels present in the inner mitochondrial membrane. In this article, we present an overview of the key findings and characteristics of mitochondrial potassium channels derived from research of many groups conducted over the past 33 years. We propose a list of six fundamental observations and most important ideas dealing with mitochondrial potassium channels. We also discuss the contemporary challenges and future prospects associated with research on mitochondrial potassium channels.
Collapse
Affiliation(s)
- Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| |
Collapse
|
2
|
Flori L, Spezzini J, Calderone V, Testai L. Role of mitochondrial potassium channels in ageing. Mitochondrion 2024; 76:101857. [PMID: 38403095 DOI: 10.1016/j.mito.2024.101857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Ageing is described as an inevitable decline in body functions over time and an increase in susceptibility to age-related diseases. Therefore, the increase of life expectancy is also viewed as a condition in which many elderly will develop age-related diseases and disabilities, such as cardiovascular, metabolic, neurological and oncological ones. Currently, several recognized cellular hallmarks of senescence are taken in consideration to evaluate the level of biological ageing and are the topic to plan preventive/curative anti-ageing interventions, including genomic instability, epigenetic alterations, and mitochondrial dysfunction. In this scenario, alterations in the function/expression of mitochondrial ion channels have been found in ageing and associated to an impairment of calcium cycling and a reduced mitochondrial membrane potential. Although several ion channels have been described at mitochondrial level, undoubtedly the mitochondrial potassium (mitoK) channels are the most investigated. Therefore, this review summarized the evidence that sheds to light a correlation between age-related diseases and alteration of mitoK channels, focusing the attention of the main age-related diseases, i.e. cardiovascular, neurological and oncological ones.
Collapse
Affiliation(s)
- Lorenzo Flori
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Vincenzo Calderone
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Research Centre of Ageing Biology and Pathology, University of Pisa, Pisa, Italy
| | - Lara Testai
- Department of Pharmacy, University of Pisa, Pisa, Italy; Interdepartmental Research Centre of Ageing Biology and Pathology, University of Pisa, Pisa, Italy.
| |
Collapse
|
3
|
Lewandowska J, Kalenik B, Wrzosek A, Szewczyk A. Redox Regulation of Mitochondrial Potassium Channels Activity. Antioxidants (Basel) 2024; 13:434. [PMID: 38671882 PMCID: PMC11047711 DOI: 10.3390/antiox13040434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/28/2024] Open
Abstract
Redox reactions exert a profound influence on numerous cellular functions with mitochondria playing a central role in orchestrating these processes. This pivotal involvement arises from three primary factors: (1) the synthesis of reactive oxygen species (ROS) by mitochondria, (2) the presence of a substantial array of redox enzymes such as respiratory chain, and (3) the responsiveness of mitochondria to the cellular redox state. Within the inner mitochondrial membrane, a group of potassium channels, including ATP-regulated, large conductance calcium-activated, and voltage-regulated channels, is present. These channels play a crucial role in conditions such as cytoprotection, ischemia/reperfusion injury, and inflammation. Notably, the activity of mitochondrial potassium channels is intricately governed by redox reactions. Furthermore, the regulatory influence extends to other proteins, such as kinases, which undergo redox modifications. This review aims to offer a comprehensive exploration of the modulation of mitochondrial potassium channels through diverse redox reactions with a specific focus on the involvement of ROS.
Collapse
Affiliation(s)
| | | | | | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (J.L.); (B.K.); (A.W.)
| |
Collapse
|
4
|
Kampa RP, Flori L, Sęk A, Spezzini J, Brogi S, Szewczyk A, Calderone V, Bednarczyk P, Testai L. Luteolin-Induced Activation of Mitochondrial BK Ca Channels: Undisclosed Mechanism of Cytoprotection. Antioxidants (Basel) 2022; 11:1892. [PMID: 36290615 PMCID: PMC9598376 DOI: 10.3390/antiox11101892] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 09/29/2023] Open
Abstract
Luteolin (LUT) is a well-known flavonoid that exhibits a number of beneficial properties. Among these, it shows cardioprotective effects, as confirmed by numerous studies. However, its effect on mitochondrial potassium channels, the activation of which is related to cytoprotection, as well as on heart ischemia/reperfusion (I/R) damage prevention, has not yet been investigated. The large conductance calcium-regulated potassium channel (mitoBKCa) has been identified in both the mitochondria of the vascular endothelial cells, which plays a significant role in the functioning of the cardiovascular system under oxidative stress-related conditions, and in the mitochondria of cardiomyocytes, where it is deeply involved in cardiac protection against I/R injury. Therefore, the aim of this study was to explore the role of the mitoBKCa channel in luteolin-induced cytoprotection. A number of in vitro, in vivo, ex vivo and in silico studies have confirmed that luteolin activates this channel in the mitochondria of cardiomyocytes and endothelial cells, which in turn leads to the protection of the endothelium and a significant reduction in the extent of damage resulting from myocardial infarction, where this effect was partially abolished by the mitoBKCa channel blocker paxilline. In conclusion, these results suggest that luteolin has cardioprotective effects, at least in part, through the activation of the mitoBKCa channel, shedding light on a new putative mechanism of action.
Collapse
Affiliation(s)
- Rafał P. Kampa
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
- Department of Pharmacology, Faculty of Pharmacy, University of Pisa, 6 via Bonanno Pisano, 56120 Pisa, Italy
| | - Lorenzo Flori
- Department of Pharmacology, Faculty of Pharmacy, University of Pisa, 6 via Bonanno Pisano, 56120 Pisa, Italy
| | - Aleksandra Sęk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Jacopo Spezzini
- Department of Pharmacology, Faculty of Pharmacy, University of Pisa, 6 via Bonanno Pisano, 56120 Pisa, Italy
| | - Simone Brogi
- Department of Pharmacology, Faculty of Pharmacy, University of Pisa, 6 via Bonanno Pisano, 56120 Pisa, Italy
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Vincenzo Calderone
- Department of Pharmacology, Faculty of Pharmacy, University of Pisa, 6 via Bonanno Pisano, 56120 Pisa, Italy
| | - Piotr Bednarczyk
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences–SGGW (WULS-SGGW), 159 Nowoursynowska St., 02-776 Warsaw, Poland
| | - Lara Testai
- Department of Pharmacology, Faculty of Pharmacy, University of Pisa, 6 via Bonanno Pisano, 56120 Pisa, Italy
| |
Collapse
|
5
|
To what extent naringenin binding and membrane depolarization shape mitoBK channel gating—A machine learning approach. PLoS Comput Biol 2022; 18:e1010315. [PMID: 35857767 PMCID: PMC9342765 DOI: 10.1371/journal.pcbi.1010315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 08/01/2022] [Accepted: 06/16/2022] [Indexed: 11/19/2022] Open
Abstract
The large conductance voltage- and Ca2+-activated K+ channels from the inner mitochondrial membrane (mitoBK) are modulated by a number of factors. Among them flavanones, including naringenin (Nar), arise as a promising group of mitoBK channel regulators from a pharmacological point of view. It is well known that in the presence of Nar the open state probability (pop) of mitoBK channels significantly increases. Nevertheless, the molecular mechanism of the mitoBK-Nar interactions remains still unrevealed. It is also not known whether the effects of naringenin administration on conformational dynamics can resemble those which are exerted by the other channel-activating stimuli. In aim to answer this question, we examine whether the dwell-time series of mitoBK channels which were obtained at different voltages and Nar concentrations (yet allowing to reach comparable pops) are discernible by means of artificial intelligence methods, including k-NN and shapelet learning. The obtained results suggest that the structural complexity of the gating dynamics is shaped both by the interaction of channel gate with the voltage sensor (VSD) and the Nar-binding site. For a majority of data one can observe stimulus-specific patterns of channel gating. Shapelet algorithm allows to obtain better prediction accuracy in most cases. Probably, because it takes into account the complexity of local features of a given signal. About 30% of the analyzed time series do not sufficiently differ to unambiguously distinguish them from each other, which can be interpreted in terms of the existence of the common features of mitoBK channel gating regardless of the type of activating stimulus. There exist long-range mutual interactions between VSD and the Nar-coordination site that are responsible for higher levels of Nar-activation (Δpop) at deeply depolarized membranes. These intra-sensor interactions are anticipated to have an allosteric nature.
Collapse
|
6
|
Nazari M, Vajed-Samiei T, Torabi N, Fahanik-Babaei J, Saghiri R, Khodagholi F, Eliassi A. The 40-Hz White Light-Emitting Diode (LED) Improves the Structure-Function of the Brain Mitochondrial KATP Channel and Respiratory Chain Activities in Amyloid Beta Toxicity. Mol Neurobiol 2022; 59:2424-2440. [PMID: 35083663 DOI: 10.1007/s12035-021-02681-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/04/2021] [Indexed: 11/29/2022]
Abstract
It has been described that using noninvasive exposure to 40-Hz white light LED reduces amyloid-beta, a peptide thought to initiate neurotoxic events in Alzheimer's disease (AD). However, the mechanisms remain to be identified. Since AD impairs mitochondrial potassium channels and respiratory chain activity, the objectives of the current study were to determine the effect of 40-Hz white light LED on structure-function of mitoKATP channel and brain mitochondrial respiratory chain activity, production of reactive oxygen species (ROS), and ΔΨm in AD. Single mitoKATP channel was considered using a channel incorporated into the bilayer lipid membrane and expression of mitoKATP-Kir6.1 subunit as a pore-forming subunit of the channel was determined using a western blot analysis in Aβ1-42 toxicity and light-treated rats. Our results indicated a severe decrease in mito-KATP channel permeation and Kir6.1 subunit expression coming from the Aβ1-42-induced neurotoxicity. Furthermore, we found that Aβ1-42-induced neurotoxicity decreased activities of complexes I and IV and increased ROS production and ΔΨm. Surprisingly, light therapy increased channel permeation and mitoKATP-Kir6.1 subunit expression. Noninvasive 40-Hz white light LED treatment also increased activities of complexes I and IV and decreased ROS production and ΔΨm up to ~ 70%. Here, we report that brain mito-KATP channel and respiratory chain are, at least in part, novel targets of 40-Hz white light LED therapy in AD.
Collapse
Affiliation(s)
- Maryam Nazari
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, 1985717443, Evin, Tehran, Iran
| | - Taha Vajed-Samiei
- School of Electrical and Computer Engineering, Tehran University, Tehran, Iran
| | - Nihad Torabi
- Department of Physiology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Javad Fahanik-Babaei
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Saghiri
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Fariba Khodagholi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Evin, Tehran, Iran
| | - Afsaneh Eliassi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. .,Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, 1985717443, Evin, Tehran, Iran.
| |
Collapse
|
7
|
Methods of Measuring Mitochondrial Potassium Channels: A Critical Assessment. Int J Mol Sci 2022; 23:ijms23031210. [PMID: 35163132 PMCID: PMC8835872 DOI: 10.3390/ijms23031210] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/22/2022] Open
Abstract
In this paper, the techniques used to study the function of mitochondrial potassium channels are critically reviewed. The majority of these techniques have been known for many years as a result of research on plasma membrane ion channels. Hence, in this review, we focus on the critical evaluation of techniques used in the studies of mitochondrial potassium channels, describing their advantages and limitations. Functional analysis of mitochondrial potassium channels in comparison to that of plasmalemmal channels presents additional experimental challenges. The reliability of functional studies of mitochondrial potassium channels is often affected by the need to isolate mitochondria and by functional properties of mitochondria such as respiration, metabolic activity, swelling capacity, or high electrical potential. Three types of techniques are critically evaluated: electrophysiological techniques, potassium flux measurements, and biochemical techniques related to potassium flux measurements. Finally, new possible approaches to the study of the function of mitochondrial potassium channels are presented. We hope that this review will assist researchers in selecting reliable methods for studying, e.g., the effects of drugs on mitochondrial potassium channel function. Additionally, this review should aid in the critical evaluation of the results reported in various articles on mitochondrial potassium channels.
Collapse
|
8
|
Wrzosek A, Gałecka S, Żochowska M, Olszewska A, Kulawiak B. Alternative Targets for Modulators of Mitochondrial Potassium Channels. Molecules 2022; 27:299. [PMID: 35011530 PMCID: PMC8746388 DOI: 10.3390/molecules27010299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial potassium channels control potassium influx into the mitochondrial matrix and thus regulate mitochondrial membrane potential, volume, respiration, and synthesis of reactive oxygen species (ROS). It has been found that pharmacological activation of mitochondrial potassium channels during ischemia/reperfusion (I/R) injury activates cytoprotective mechanisms resulting in increased cell survival. In cancer cells, the inhibition of these channels leads to increased cell death. Therefore, mitochondrial potassium channels are intriguing targets for the development of new pharmacological strategies. In most cases, however, the substances that modulate the mitochondrial potassium channels have a few alternative targets in the cell. This may result in unexpected or unwanted effects induced by these compounds. In our review, we briefly present the various classes of mitochondrial potassium (mitoK) channels and describe the chemical compounds that modulate their activity. We also describe examples of the multidirectional activity of the activators and inhibitors of mitochondrial potassium channels.
Collapse
Affiliation(s)
- Antoni Wrzosek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Shur Gałecka
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Monika Żochowska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Anna Olszewska
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211 Gdansk, Poland;
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Kulawiak B, Bednarczyk P, Szewczyk A. Multidimensional Regulation of Cardiac Mitochondrial Potassium Channels. Cells 2021; 10:1554. [PMID: 34205420 PMCID: PMC8235349 DOI: 10.3390/cells10061554] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondria play a fundamental role in the energetics of cardiac cells. Moreover, mitochondria are involved in cardiac ischemia/reperfusion injury by opening the mitochondrial permeability transition pore which is the major cause of cell death. The preservation of mitochondrial function is an essential component of the cardioprotective mechanism. The involvement of mitochondrial K+ transport in this complex phenomenon seems to be well established. Several mitochondrial K+ channels in the inner mitochondrial membrane, such as ATP-sensitive, voltage-regulated, calcium-activated and Na+-activated channels, have been discovered. This obliges us to ask the following question: why is the simple potassium ion influx process carried out by several different mitochondrial potassium channels? In this review, we summarize the current knowledge of both the properties of mitochondrial potassium channels in cardiac mitochondria and the current understanding of their multidimensional functional role. We also critically summarize the pharmacological modulation of these proteins within the context of cardiac ischemia/reperfusion injury and cardioprotection.
Collapse
Affiliation(s)
- Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland;
| | - Piotr Bednarczyk
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland;
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland;
| |
Collapse
|
11
|
Torabi N, Noursadeghi E, Shayanfar F, Nazari M, Fahanik-Babaei J, Saghiri R, Khodagholi F, Eliassi A. Intranasal insulin improves the structure-function of the brain mitochondrial ATP-sensitive Ca 2+ activated potassium channel and respiratory chain activities under diabetic conditions. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166075. [PMID: 33444710 DOI: 10.1016/j.bbadis.2021.166075] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/06/2020] [Accepted: 12/30/2020] [Indexed: 11/21/2022]
Abstract
Although it is well established that diabetes impairs mitochondrial respiratory chain activity, little is known of the effects of intranasal insulin (INI) on the mitochondrial respiratory chain and structure-function of mitoBKCa channel in diabetes. We have investigated this mechanism in an STZ-induced early type 2 diabetic model. Single ATP-sensitive mitoBKCa channel activity was considered in diabetic and INI-treated rats using a channel incorporated into the bilayer lipid membrane. Because mitoBKCa channels have been involved in mitochondrial respiratory chain activity, a study was undertaken to investigate whether the NADH, complexes I and IV, mitochondrial ROS production, and ΔΨm are altered in an early diabetic model. In this work, we provide evidence for a significant decrease in channel open probability and conductance in diabetic rats. Evidence has been shown that BKCa channel β2 subunits induce a left shift in the BKCa channel voltage dependent curve in low Ca2+ conditions,; our results indicated a significant decrease in mitoBKCa β2 subunits using Western blot analysis. Importantly, INI treatment improved mitoBKCa channel behaviors and β2 subunits expression up to ~70%. We found that early diabetes decreased activities of complex I and IV and increased NADH, ROS production, and ΔΨm. Surprisingly, INI modified the mitochondrial respiratory chain, ROS production, and ΔΨm up to ~70%. Our results thus demonstrate an INI improvement in respiratory chain activity and ROS production in brain mitochondrial preparations coming from the STZ early diabetic rat model, an effect potentially linked to INI improvement in mitoBKCa channel activity and channel β2 subunit expression.
Collapse
Affiliation(s)
- Nihad Torabi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elham Noursadeghi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farzad Shayanfar
- Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Nazari
- Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Javad Fahanik-Babaei
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Saghiri
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Fariba Khodagholi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Evin, Tehran, Iran
| | - Afsaneh Eliassi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
12
|
Application of Machine-Learning Methods to Recognize mitoBK Channels from Different Cell Types Based on the Experimental Patch-Clamp Results. Int J Mol Sci 2021; 22:ijms22020840. [PMID: 33467711 PMCID: PMC7831025 DOI: 10.3390/ijms22020840] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/03/2021] [Accepted: 01/11/2021] [Indexed: 12/03/2022] Open
Abstract
(1) Background: In this work, we focus on the activity of large-conductance voltage- and Ca2+-activated potassium channels (BK) from the inner mitochondrial membrane (mitoBK). The characteristic electrophysiological features of the mitoBK channels are relatively high single-channel conductance (ca. 300 pS) and types of activating and deactivating stimuli. Nevertheless, depending on the isoformal composition of mitoBK channels in a given membrane patch and the type of auxiliary regulatory subunits (which can be co-assembled to the mitoBK channel protein) the characteristics of conformational dynamics of the channel protein can be altered. Consequently, the individual features of experimental series describing single-channel activity obtained by patch-clamp method can also vary. (2) Methods: Artificial intelligence approaches (deep learning) were used to classify the patch-clamp outputs of mitoBK activity from different cell types. (3) Results: Application of the K-nearest neighbors algorithm (KNN) and the autoencoder neural network allowed to perform the classification of the electrophysiological signals with a very good accuracy, which indicates that the conformational dynamics of the analyzed mitoBK channels from different cell types significantly differs. (4) Conclusion: We displayed the utility of machine-learning methodology in the research of ion channel gating, even in cases when the behavior of very similar microbiosystems is analyzed. A short excerpt from the patch-clamp recording can serve as a “fingerprint” used to recognize the mitoBK gating dynamics in the patches of membrane from different cell types.
Collapse
|
13
|
Wawrzkiewicz-Jałowiecka A, Trybek P, Borys P, Dworakowska B, Machura Ł, Bednarczyk P. Differences in Gating Dynamics of BK Channels in Cellular and Mitochondrial Membranes from Human Glioblastoma Cells Unraveled by Short- and Long-Range Correlations Analysis. Cells 2020; 9:E2305. [PMID: 33076484 PMCID: PMC7602617 DOI: 10.3390/cells9102305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 02/04/2023] Open
Abstract
The large-conductance voltage- and Ca2+-activated K+ channels (BK) are encoded in humans by the Kcnma1 gene. Nevertheless, BK channel isoforms in different locations can exhibit functional heterogeneity mainly due to the alternative splicing during the Kcnma1 gene transcription. Here, we would like to examine the existence of dynamic diversity of BK channels from the inner mitochondrial and cellular membrane from human glioblastoma (U-87 MG). Not only the standard characteristics of the spontaneous switching between the functional states of the channel is discussed, but we put a special emphasis on the presence and strength of correlations within the signal describing the single-channel activity. The considered short- and long-range memory effects are here analyzed as they can be interpreted in terms of the complexity of the switching mechanism between stable conformational states of the channel. We calculate the dependencies of mean dwell-times of (conducting/non-conducting) states on the duration of the previous state, Hurst exponents by the rescaled range R/S method and detrended fluctuation analysis (DFA), and use the multifractal extension of the DFA (MFDFA) for the series describing single-channel activity. The obtained results unraveled statistically significant diversity in gating machinery between the mitochondrial and cellular BK channels.
Collapse
Affiliation(s)
- Agata Wawrzkiewicz-Jałowiecka
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, 44-100 Gliwice, Poland;
| | - Paulina Trybek
- Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzow, Poland;
| | - Przemysław Borys
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, 44-100 Gliwice, Poland;
| | - Beata Dworakowska
- Institute of Biology, Department of Physics and Biophysics, Warsaw University of Life Sciences—SGGW, 02-787 Warszawa, Poland; (B.D.); (P.B.)
| | - Łukasz Machura
- Institute of Physics, Faculty of Science and Technology, University of Silesia in Katowice, 41-500 Chorzow, Poland;
| | - Piotr Bednarczyk
- Institute of Biology, Department of Physics and Biophysics, Warsaw University of Life Sciences—SGGW, 02-787 Warszawa, Poland; (B.D.); (P.B.)
| |
Collapse
|
14
|
Wrzosek A, Augustynek B, Żochowska M, Szewczyk A. Mitochondrial Potassium Channels as Druggable Targets. Biomolecules 2020; 10:E1200. [PMID: 32824877 PMCID: PMC7466137 DOI: 10.3390/biom10081200] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/03/2020] [Accepted: 08/13/2020] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial potassium channels have been described as important factors in cell pro-life and death phenomena. The activation of mitochondrial potassium channels, such as ATP-regulated or calcium-activated large conductance potassium channels, may have cytoprotective effects in cardiac or neuronal tissue. It has also been shown that inhibition of the mitochondrial Kv1.3 channel may lead to cancer cell death. Hence, in this paper, we examine the concept of the druggability of mitochondrial potassium channels. To what extent are mitochondrial potassium channels an important, novel, and promising drug target in various organs and tissues? The druggability of mitochondrial potassium channels will be discussed within the context of channel molecular identity, the specificity of potassium channel openers and inhibitors, and the unique regulatory properties of mitochondrial potassium channels. Future prospects of the druggability concept of mitochondrial potassium channels will be evaluated in this paper.
Collapse
Affiliation(s)
| | | | | | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (B.A.); (M.Ż.)
| |
Collapse
|
15
|
Sánchez-Duarte E, Cortés-Rojo C, Sánchez-Briones LA, Campos-García J, Saavedra-Molina A, Delgado-Enciso I, López-Lemus UA, Montoya-Pérez R. Nicorandil Affects Mitochondrial Respiratory Chain Function by Increasing Complex III Activity and ROS Production in Skeletal Muscle Mitochondria. J Membr Biol 2020; 253:309-318. [PMID: 32620983 DOI: 10.1007/s00232-020-00129-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 06/23/2020] [Indexed: 12/15/2022]
Abstract
Adenosine triphosphate (ATP)-dependent potassium channels openers (KATP) protect skeletal muscle against function impairment through the activation of the mitochondrial KATP channels (mitoKATP). Previous reports suggest that modulators of the mitochondrial KATP channels have additional effects on isolated mitochondria. To determine whether the KATP channel opener nicorandil has non-specific effects that explain its protective effect through the mitochondrial function, chicken muscle mitochondria were isolated, and respiration rate was determined pollarographically. The activity of the electron transport chain (ETC) complexes (I-IV) was measured using a spectrophotometric method. Reactive oxygen species (ROS) levels and lipid peroxidation were assessed using flow cytometry and thiobarbituric acid assay, respectively. Both KATP channel opener nicorandil and KATP channel blocker 5-hydroxydecanoate (5-HD) decreased mitochondrial respiration; nicorandil increased complex III activity and decreased complex IV activity. The effects of nicorandil on complex III were antagonized by 5-HD. Nicorandil increased ROS levels, effect reverted by either 5-HD or the antioxidant N-2-mercaptopropionyl glycine (MPG). None of these drugs affected lipid peroxidation levels. These findings suggest that KATP channel opener nicorandil increases mitochondrial ROS production from complex III. This results by partially blocking electron flow in the complex IV, setting electron carriers in a more reduced state, which is favored by the increase in complex III activity by nicorandil. Overall, our study showed that nicorandil like other mitochondrial KATP channel openers might not act through mitoKATP channel activation.
Collapse
Affiliation(s)
- E Sánchez-Duarte
- Departamento de Ciencias Aplicadas al Trabajo, Universidad de Guanajuato Campus León, Eugenio Garza Sada 572, Lomas del Campestre Sección 2, 37150, León, Guanajuato, Mexico
| | - C Cortés-Rojo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, Mexico
| | - L A Sánchez-Briones
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, Mexico
| | - J Campos-García
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, Mexico
| | - A Saavedra-Molina
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, Mexico
| | - I Delgado-Enciso
- Facultad de Medicina, Universidad de Colima, Av. Universidad 333. Las Víboras, 28040, Colima, Colima, Mexico
| | - U A López-Lemus
- Center for Biodefense and Global Infectious Diseases, 28078, Colima, Colima, Mexico
| | - R Montoya-Pérez
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Múgica S/N, Col. Felicitas del Río, 58030, Morelia, Michoacán, Mexico.
| |
Collapse
|
16
|
Regulation of the Mitochondrial BK Ca Channel by the Citrus Flavonoid Naringenin as a Potential Means of Preventing Cell Damage. Molecules 2020; 25:molecules25133010. [PMID: 32630135 PMCID: PMC7412269 DOI: 10.3390/molecules25133010] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 12/27/2022] Open
Abstract
Naringenin, a flavanone obtained from citrus fruits and present in many traditional Chinese herbal medicines, has been shown to have various beneficial effects on cells both in vitro and in vivo. Although the antioxidant activity of naringenin has long been believed to be crucial for its effects on cells, mitochondrial pathways (including mitochondrial ion channels) are emerging as potential targets for the specific pharmacological action of naringenin in cardioprotective strategies. In the present study, we describe interactions between the mitochondrial large-conductance calcium-regulated potassium channel (mitoBKCa channel) and naringenin. Using the patch-clamp method, we showed that 10 µM naringenin activated the mitoBKCa channel present in endothelial cells. In the presence of 30 µM Ca2+, the increase in the mitoBKCa channel probability of opening from approximately 0.25 to 0.50 at −40 mV was observed. In addition, regulation of the mitoBKCa channel by naringenin was dependent on the concentration of calcium ions. To confirm our data, physiological studies on the mitochondria were performed. An increase in oxygen consumption and a decrease in membrane potential was observed after naringenin treatment. In addition, contributions of the mitoBKCa channel to apoptosis and necrosis were investigated. Naringenin protected cells against damage induced by tumor necrosis factor α (TNF-α) in combination with cycloheximide. In this study, we demonstrated that the flavonoid naringenin can activate the mitoBKCa channel present in the inner mitochondrial membrane of endothelial cells. Our studies describing the regulation of the mitoBKCa channel by this natural, plant-derived substance may help to elucidate flavonoid-induced cytoprotective mechanisms.
Collapse
|
17
|
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.
Collapse
|
18
|
Mitigating effect of paxilline against injury produced by Cd 2+ in rat pheochromocytoma PC12 and ascites hepatoma AS-30D cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 196:110519. [PMID: 32244116 DOI: 10.1016/j.ecoenv.2020.110519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/15/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023]
Abstract
On two rat cell lines, pheochromocytoma PC12 and ascites hepatoma AS-30D, and on rat liver mitochondria we studied action of paxilline (lipophilic mycotoxin from fungus Penicillium paxilli which is blocker of large-conductance potassium channels) against harmful effects of Cd(II) - one of the most dangerous toxic metals and environmental pollutants. We investigated an influence of paxilline on cell viability and mitochondrial function in the presence and in the absence of Cd2+. As found, paxilline protected partially from the Cd2+-induced cytotoxicity, namely taken in concentration of 1 μM it decreased the Cd2+-induced cell necrosis in average by 10-14 or 13-23% for AS-30D and PC12 cells, respectively. Nevertheless, paxilline did not affect the Cd2+-induced apoptosis of AS-30D cells. The alleviating concentration of paxilline reduced an intracellular production of reactive oxygen species (ROS) in PC12 cells intoxicated by Cd2+ and enhanced the ROS production in control AS-30D cells; however, it weakly affected mitochondrial membrane potential of the cells in the absence and in the presence of Cd2+. The ameliorative concentration of paxilline decreased the maximal respiration rates of control cells of both types after short-term (3-5 h) treatment with it while the rates reached their control levels after long-term (24-48 h) incubation with the drug. Paxilline was not protective against the Cd2+-induced membrane permeability and respiration rate changes in isolated rat liver mitochondria. As result, the mitochondrial electron transport chain was concluded to contribute in the mitigating effect of paxilline against the Cd2+-produced cell injury.
Collapse
|
19
|
Fahanik-Babaei J, Rezaee B, Nazari M, Torabi N, Saghiri R, Sauve R, Eliassi A. A new brain mitochondrial sodium-sensitive potassium channel: effect of sodium ions on respiratory chain activity. J Cell Sci 2020; 133:jcs242446. [PMID: 32327555 DOI: 10.1242/jcs.242446] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 03/30/2020] [Indexed: 12/17/2022] Open
Abstract
We have determined the electropharmacological properties of a new potassium channel from brain mitochondrial membrane using a planar lipid bilayer method. Our results show the presence of a channel with a conductance of 150 pS at potentials between 0 and -60 mV in 200 mM cis/50 mM trans KCl solutions. The channel was voltage independent, with an open probability value of approximately 0.6 at different voltages. ATP did not affect current amplitude or open probability at positive and negative voltages. Notably, adding iberiotoxin, charybdotoxin, lidocaine or margatoxin had no effect on the channel behavior. Similarly, no changes were observed by decreasing the cis pH to 6. Interestingly, the channel was inhibited by adding sodium in a dose-dependent manner. Our results also indicated a significant increase in mitochondrial complex IV activity and membrane potential and a decrease in complex I activity and mitochondrial ROS production in the presence of sodium ions. We propose that inhibition of mitochondrial potassium transport by sodium ions on potassium channel opening could be important for cell protection and ATP synthesis.
Collapse
Affiliation(s)
- Javad Fahanik-Babaei
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran 1419733141, Iran
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran 1985717443, Iran
| | - Bahareh Rezaee
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran 1985717443, Iran
| | - Maryam Nazari
- Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran 1985717443, Iran
| | - Nihad Torabi
- Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran 1985717443, Iran
| | - Reza Saghiri
- Department of Biochemistry, Pasteur Institute of Iran, Tehran 1985717443, Iran
| | - Remy Sauve
- Department of Pharmacology and Physiology and Membrane Protein Research Group, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Afsaneh Eliassi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran 1985717443, Iran
- Department of Physiology, Shahid Beheshti University of Medical Sciences, Tehran 1985717443, Iran
| |
Collapse
|
20
|
The Effect of Ginsenoside RB1, Diazoxide, and 5-Hydroxydecanoate on Hypoxia-Reoxygenation Injury of H9C2 Cardiomyocytes. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:6046405. [PMID: 31915449 PMCID: PMC6930760 DOI: 10.1155/2019/6046405] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/21/2019] [Accepted: 11/28/2019] [Indexed: 01/08/2023]
Abstract
This study was aimed to investigate whether ginsenoside Rb1 (GS-Rb1) from the cardioprotective Chinese medicine ginseng can reduce hypoxia-reoxygenation (HR)-induced damage to cardiomyocytes by protecting the mitochondria. Mitochondria-mediated apoptosis plays a key role during myocardial ischemia-reperfusion injury (MIRI). When MIRI occurs, the continuous opening of the mitochondrial permeability transition pore (mPTP) causes mitochondrial damage and ultimately leads to apoptosis. We treated H9c2 cells, derived from rat embryonic cardiomyoblasts, with GS-Rb1, diazoxide, and 5-hydroxydecanoate (5-HD), using HR to simulate MIRI. We found that GS-Rb1 can reduce mPTP by stabilizing the mitochondrial membrane potential (MMP) and by reducing reactive oxygen species (ROS) during HR. This protects the mitochondria by reducing the release of cytochrome c and the expression of cleaved-caspase-3 in the cytoplasm, ultimately reducing apoptosis. During this process, GS-Rb1 and diazoxide showed similar effects. These findings provide some evidence for a protective effect of GS-Rb1 treatment on MIRI.
Collapse
|
21
|
Jarmuszkiewicz W, Szewczyk A. Energy-dissipating hub in muscle mitochondria: Potassium channels and uncoupling proteins. Arch Biochem Biophys 2019; 664:102-109. [DOI: 10.1016/j.abb.2019.01.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 01/15/2023]
|
22
|
Leanza L, Checchetto V, Biasutto L, Rossa A, Costa R, Bachmann M, Zoratti M, Szabo I. Pharmacological modulation of mitochondrial ion channels. Br J Pharmacol 2019; 176:4258-4283. [PMID: 30440086 DOI: 10.1111/bph.14544] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/15/2018] [Accepted: 10/22/2018] [Indexed: 12/17/2022] Open
Abstract
The field of mitochondrial ion channels has undergone a rapid development during the last three decades, due to the molecular identification of some of the channels residing in the outer and inner membranes. Relevant information about the function of these channels in physiological and pathological settings was gained thanks to genetic models for a few, mitochondria-specific channels. However, many ion channels have multiple localizations within the cell, hampering a clear-cut determination of their function by pharmacological means. The present review summarizes our current knowledge about the ins and outs of mitochondrial ion channels, with special focus on the channels that have received much attention in recent years, namely, the voltage-dependent anion channels, the permeability transition pore (also called mitochondrial megachannel), the mitochondrial calcium uniporter and some of the inner membrane-located potassium channels. In addition, possible strategies to overcome the difficulties of specifically targeting mitochondrial channels versus their counterparts active in other membranes are discussed, as well as the possibilities of modulating channel function by small peptides that compete for binding with protein interacting partners. Altogether, these promising tools along with large-scale chemical screenings set up to identify new, specific channel modulators will hopefully allow us to pinpoint the actual function of most mitochondrial ion channels in the near future and to pharmacologically affect important pathologies in which they are involved, such as neurodegeneration, ischaemic damage and cancer. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.
Collapse
Affiliation(s)
- Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy
| | | | - Lucia Biasutto
- CNR Institute of Neurosciences, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Andrea Rossa
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Roberto Costa
- Department of Biology, University of Padova, Padova, Italy
| | | | - Mario Zoratti
- CNR Institute of Neurosciences, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.,CNR Institute of Neurosciences, Department of Biomedical Sciences, University of Padova, Padova, Italy
| |
Collapse
|
23
|
Dolowy K. Calcium phosphate buffer formed in the mitochondrial matrix during preconditioning supports ΔpH formation and ischemic ATP production and prolongs cell survival -A hypothesis. Mitochondrion 2018; 47:210-217. [PMID: 30448366 DOI: 10.1016/j.mito.2018.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 05/06/2018] [Accepted: 11/14/2018] [Indexed: 10/27/2022]
Abstract
Ischemic preconditioning makes cells less sensitive to oxygen deprivation. A similar effect can be achieved by increasing the calcium concentration and applying potassium channel openers. A hypothetical mechanism of preconditioning is presented. In the mitochondrial matrix, there is a calcium hydroxide buffer consisting of a few insoluble calcium phosphate minerals. During ischemia, calcium ions stored in the matrix buffer start to leak out, forming an electric potential difference, while hydroxyl ions remain in the matrix, maintaining its pH and the matrix volume. Preconditioning factors increase the matrix buffer capacity. Production of ATP during ischemia might be the relic of a pre-endosymbiotic past.
Collapse
Affiliation(s)
- Krzysztof Dolowy
- Department of Biophysics, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, Warszawa 02-776, Poland.
| |
Collapse
|
24
|
Kshatri AS, Gonzalez-Hernandez A, Giraldez T. Physiological Roles and Therapeutic Potential of Ca 2+ Activated Potassium Channels in the Nervous System. Front Mol Neurosci 2018; 11:258. [PMID: 30104956 PMCID: PMC6077210 DOI: 10.3389/fnmol.2018.00258] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/06/2018] [Indexed: 12/21/2022] Open
Abstract
Within the potassium ion channel family, calcium activated potassium (KCa) channels are unique in their ability to couple intracellular Ca2+ signals to membrane potential variations. KCa channels are diversely distributed throughout the central nervous system and play fundamental roles ranging from regulating neuronal excitability to controlling neurotransmitter release. The physiological versatility of KCa channels is enhanced by alternative splicing and co-assembly with auxiliary subunits, leading to fundamental differences in distribution, subunit composition and pharmacological profiles. Thus, understanding specific KCa channels’ mechanisms in neuronal function is challenging. Based on their single channel conductance, KCa channels are divided into three subtypes: small (SK, 4–14 pS), intermediate (IK, 32–39 pS) and big potassium (BK, 200–300 pS) channels. This review describes the biophysical characteristics of these KCa channels, as well as their physiological roles and pathological implications. In addition, we also discuss the current pharmacological strategies and challenges to target KCa channels for the treatment of various neurological and psychiatric disorders.
Collapse
Affiliation(s)
- Aravind S Kshatri
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| | - Alberto Gonzalez-Hernandez
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| | - Teresa Giraldez
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| |
Collapse
|
25
|
|
26
|
Bednarczyk P, Kicinska A, Laskowski M, Kulawiak B, Kampa R, Walewska A, Krajewska M, Jarmuszkiewicz W, Szewczyk A. Evidence for a mitochondrial ATP-regulated potassium channel in human dermal fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:309-318. [PMID: 29458000 DOI: 10.1016/j.bbabio.2018.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 01/04/2018] [Accepted: 02/14/2018] [Indexed: 02/07/2023]
Abstract
Mitochondrial ATP-regulated potassium channels are present in the inner membrane of the mitochondria of various cells. In the present study, we show for the first time mitochondrial ATP-regulated potassium channels in human dermal fibroblast cells. Using the patch-clamp technique on the inner mitochondrial membrane of fibroblasts, we detected a potassium channel with a mean conductance equal to 100 pS in symmetric 150 mM KCl. The activity of this channel was inhibited by a complex of ATP/Mg2+ and activated by potassium channel openers such as diazoxide or BMS 191095. Channel activity was inhibited by antidiabetic sulfonylurea glibenclamide and 5-hydroxydecanoic acid. The influence of substances modulating ATP-regulated potassium channel activity on oxygen consumption and membrane potential of isolated fibroblast mitochondria was also studied. Additionally, the potassium channel opener diazoxide lowered the amount of superoxide formed in isolated fibroblast mitochondria. Using reverse transcriptase-PCR, we found an mRNA transcript for the KCNJ1(ROMK) channel. The presence of ROMK protein was observed in the inner mitochondrial membrane fraction. Moreover, colocalization of the ROMK protein and a mitochondrial marker in the mitochondria of fibroblast cells was shown by immunofluorescence. In summary, the ATP-regulated mitochondrial potassium channel in a dermal fibroblast cell line have been identified.
Collapse
Affiliation(s)
- Piotr Bednarczyk
- Department of Biophysics, Warsaw University of Life Sciences (SGGW), Warsaw, Poland.
| | - Anna Kicinska
- Department of Bioenergetics, Adam Mickiewicz University, Poznan, Poland
| | - Michal Laskowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Rafal Kampa
- Department of Biophysics, Warsaw University of Life Sciences (SGGW), Warsaw, Poland; Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Agnieszka Walewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Milena Krajewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland
| | | | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland
| |
Collapse
|
27
|
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.
Collapse
|
28
|
Dubinin MV, Vedernikov AA, Khoroshavina EI, Smirnova AE, Samartsev VN. A comparative study of potassium ion transport in liver mitochondria of laboratory rats, pigeons (Columba livia) and guineafowl (Numida meleagris). J EVOL BIOCHEM PHYS+ 2017. [DOI: 10.1134/s0022093017040123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
29
|
Measurement of ion fluxes across epithelia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 127:1-11. [DOI: 10.1016/j.pbiomolbio.2017.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/13/2017] [Accepted: 03/18/2017] [Indexed: 12/23/2022]
|
30
|
Krabbendam IE, Honrath B, Culmsee C, Dolga AM. Mitochondrial Ca 2+-activated K + channels and their role in cell life and death pathways. Cell Calcium 2017; 69:101-111. [PMID: 28818302 DOI: 10.1016/j.ceca.2017.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022]
Abstract
Ca2+-activated K+ channels (KCa) are expressed at the plasma membrane and in cellular organelles. Expression of all KCa channel subtypes (BK, IK and SK) has been detected at the inner mitochondrial membrane of several cell types. Primary functions of these mitochondrial KCa channels include the regulation of mitochondrial ROS production, maintenance of the mitochondrial membrane potential and preservation of mitochondrial calcium homeostasis. These channels are therefore thought to contribute to cellular protection against oxidative stress through mitochondrial mechanisms of preconditioning. In this review, we summarize the current knowledge on mitochondrial KCa channels, and their role in mitochondrial function in relation to cell death and survival pathways. More specifically, we systematically discuss studies on the role of these mitochondrial KCa channels in pharmacological preconditioning, and according protective effects on ischemic insults to the brain and the heart.
Collapse
Affiliation(s)
- Inge E Krabbendam
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
| | - Birgit Honrath
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands; Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany.
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35043 Marburg, Germany.
| | - Amalia M Dolga
- Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Department of Molecular Pharmacology, University of Groningen, 9713 AV Groningen, The Netherlands.
| |
Collapse
|
31
|
Leanza L, Romio M, Becker KA, Azzolini M, Trentin L, Managò A, Venturini E, Zaccagnino A, Mattarei A, Carraretto L, Urbani A, Kadow S, Biasutto L, Martini V, Severin F, Peruzzo R, Trimarco V, Egberts JH, Hauser C, Visentin A, Semenzato G, Kalthoff H, Zoratti M, Gulbins E, Paradisi C, Szabo I. Direct Pharmacological Targeting of a Mitochondrial Ion Channel Selectively Kills Tumor Cells In Vivo. Cancer Cell 2017; 31:516-531.e10. [PMID: 28399409 DOI: 10.1016/j.ccell.2017.03.003] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 02/03/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
The potassium channel Kv1.3 is highly expressed in the mitochondria of various cancerous cells. Here we show that direct inhibition of Kv1.3 using two mitochondria-targeted inhibitors alters mitochondrial function and leads to reactive oxygen species (ROS)-mediated death of even chemoresistant cells independently of p53 status. These inhibitors killed 98% of ex vivo primary chronic B-lymphocytic leukemia tumor cells while sparing healthy B cells. In orthotopic mouse models of melanoma and pancreatic ductal adenocarcinoma, the compounds reduced tumor size by more than 90% and 60%, respectively, while sparing immune and cardiac functions. Our work provides direct evidence that specific pharmacological targeting of a mitochondrial potassium channel can lead to ROS-mediated selective apoptosis of cancer cells in vivo, without causing significant side effects.
Collapse
Affiliation(s)
- Luigi Leanza
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Matteo Romio
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy
| | - Katrin Anne Becker
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Michele Azzolini
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Livio Trentin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Antonella Managò
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Elisa Venturini
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Angela Zaccagnino
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Andrea Mattarei
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Andrea Urbani
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Stephanie Kadow
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Lucia Biasutto
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Veronica Martini
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Filippo Severin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Roberta Peruzzo
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy
| | - Valentina Trimarco
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Jan-Hendrik Egberts
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Charlotte Hauser
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Andrea Visentin
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Gianpietro Semenzato
- Department of Medicine, Hematology and Immunological Branch, University of Padova, and Venetian Institute for Molecular Medicine (VIMM), via G. Orus 2, 35129 Padova, Italy
| | - Holger Kalthoff
- Institute for Experimental Cancer Research, Medical Faculty, CAU, Kiel, and Department of Surgery, UKSH, Campus Kiel, Arnold-Heller-Strasse 3 (Haus 17), 24105 Kiel, Germany
| | - Mario Zoratti
- Department of Biomedical Sciences, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany; Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0558, USA.
| | - Cristina Paradisi
- Department of Chemical Sciences, University of Padova, via F. Marzolo 1, 35121 Padova, Italy.
| | - Ildiko Szabo
- Department of Biology, University of Padova, viale G. Colombo 3, 35121 Padova, Italy; CNR Institute of Neuroscience, viale G. Colombo 3, 35121 Padova, Italy.
| |
Collapse
|
32
|
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.
Collapse
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.
| |
Collapse
|
33
|
Peruzzo R, Biasutto L, Szabò I, Leanza L. Impact of intracellular ion channels on cancer development and progression. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2016; 45:685-707. [PMID: 27289382 PMCID: PMC5045486 DOI: 10.1007/s00249-016-1143-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 05/13/2016] [Accepted: 05/17/2016] [Indexed: 12/13/2022]
Abstract
Cancer research is nowadays focused on the identification of possible new targets in order to try to develop new drugs for curing untreatable tumors. Ion channels have emerged as "oncogenic" proteins, since they have an aberrant expression in cancers compared to normal tissues and contribute to several hallmarks of cancer, such as metabolic re-programming, limitless proliferative potential, apoptosis-resistance, stimulation of neo-angiogenesis as well as cell migration and invasiveness. In recent years, not only the plasma membrane but also intracellular channels and transporters have arisen as oncological targets and were proposed to be associated with tumorigenesis. Therefore, the research is currently focusing on understanding the possible role of intracellular ion channels in cancer development and progression on one hand and, on the other, on developing new possible drugs able to modulate the expression and/or activity of these channels. In a few cases, the efficacy of channel-targeting drugs in reducing tumors has already been demonstrated in vivo in preclinical mouse models.
Collapse
Affiliation(s)
| | - Lucia Biasutto
- CNR Institute of Neuroscience, Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Ildikò Szabò
- Department of Biology, University of Padua, Padua, Italy
- CNR Institute of Neuroscience, Padua, Italy
| | - Luigi Leanza
- Department of Biology, University of Padua, Padua, Italy.
| |
Collapse
|
34
|
Checchetto V, Teardo E, Carraretto L, Leanza L, Szabo I. Physiology of intracellular potassium channels: A unifying role as mediators of counterion fluxes? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1258-1266. [PMID: 26970213 DOI: 10.1016/j.bbabio.2016.03.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 12/28/2022]
Abstract
Plasma membrane potassium channels importantly contribute to maintain ion homeostasis across the cell membrane. The view is emerging that also those residing in intracellular membranes play pivotal roles for the coordination of correct cell function. In this review we critically discuss our current understanding of the nature and physiological tasks of potassium channels in organelle membranes in both animal and plant cells, with a special emphasis on their function in the regulation of photosynthesis and mitochondrial respiration. In addition, the emerging role of potassium channels in the nuclear membranes in regulating transcription will be discussed. The possible functions of endoplasmic reticulum-, lysosome- and plant vacuolar membrane-located channels are also referred to. Altogether, experimental evidence obtained with distinct channels in different membrane systems points to a possible unifying function of most intracellular potassium channels in counterbalancing the movement of other ions including protons and calcium and modulating membrane potential, thereby fine-tuning crucial cellular processes. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-7, 2016', edited by Prof. Paolo Bernardi.
Collapse
Affiliation(s)
- Vanessa Checchetto
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy; Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, Padova 35131 Italy
| | - Enrico Teardo
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Luigi Leanza
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy; CNR Institute of Neuroscience, University of Padova, Viale G. Colombo 3, Padova 35131, Italy.
| |
Collapse
|
35
|
Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
Collapse
Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| |
Collapse
|
36
|
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.
Collapse
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
| |
Collapse
|
37
|
The Roles of Mitochondrial Cation Channels Under Physiological Conditions and in Cancer. Handb Exp Pharmacol 2016; 240:47-69. [PMID: 27995386 DOI: 10.1007/164_2016_92] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bioenergetics has become central to our understanding of pathological mechanisms as well as the development of new therapeutic strategies and as a tool for gauging disease progression in neurodegeneration, diabetes, cancer, and cardiovascular disease. The view is emerging that inner mitochondrial membrane (IMM) cation channels have a profound effect on mitochondrial function and, consequently, on the metabolic state and survival of the whole cell. Since disruption of the sustained integrity of mitochondria is strongly linked to human disease, pharmacological intervention offers a new perspective concerning neurodegenerative and cardiovascular diseases as well as cancer. This review summarizes our current knowledge regarding IMM cation channels and their roles under physiological conditions as well as in cancer, with special emphasis on potassium channels and the mammalian mitochondrial calcium uniporter.
Collapse
|
38
|
Belyaeva EA. The effect of modulators of large-conductance Ca2+-modulated K+ channels on rat AS-30D ascites hepatoma cells and isolated liver mitochondria treated with Cd2+. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093015040018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
39
|
Balderas E, Zhang J, Stefani E, Toro L. Mitochondrial BKCa channel. Front Physiol 2015; 6:104. [PMID: 25873902 PMCID: PMC4379900 DOI: 10.3389/fphys.2015.00104] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/13/2015] [Indexed: 12/19/2022] Open
Abstract
Since its discovery in a glioma cell line 15 years ago, mitochondrial BKCa channel (mitoBKCa) has been studied in brain cells and cardiomyocytes sharing general biophysical properties such as high K+ conductance (~300 pS), voltage-dependency and Ca2+-sensitivity. Main advances in deciphering the molecular composition of mitoBKCa have included establishing that it is encoded by the Kcnma1 gene, that a C-terminal splice insert confers mitoBKCa ability to be targeted to cardiac mitochondria, and evidence for its potential coassembly with β subunits. Notoriously, β1 subunit directly interacts with cytochrome c oxidase and mitoBKCa can be modulated by substrates of the respiratory chain. mitoBKCa channel has a central role in protecting the heart from ischemia, where pharmacological activation of the channel impacts the generation of reactive oxygen species and mitochondrial Ca2+ preventing cell death likely by impeding uncontrolled opening of the mitochondrial transition pore. Supporting this view, inhibition of mitoBKCa with Iberiotoxin, enhances cytochrome c release from glioma mitochondria. Many tantalizing questions remain open. Some of them are: how is mitoBKCa coupled to the respiratory chain? Does mitoBKCa play non-conduction roles in mitochondria physiology? Which are the functional partners of mitoBKCa? What are the roles of mitoBKCa in other cell types? Answers to these questions are essential to define the impact of mitoBKCa channel in mitochondria biology and disease.
Collapse
Affiliation(s)
- Enrique Balderas
- Department of Anesthesiology, University of California, Los Angeles Los Angeles, CA, USA
| | - Jin Zhang
- Deparment of Molecular and Medical Pharmacology, University of California, Los Angeles Los Angeles, CA, USA
| | - Enrico Stefani
- Department of Anesthesiology, University of California, Los Angeles Los Angeles, CA, USA ; Department of Physiology, University of California, Los Angeles Los Angeles, CA, USA ; Brain Research Institute, University of California, Los Angeles Los Angeles, CA, USA ; Cardiovascular Research Laboratory, University of California, Los Angeles Los Angeles, CA, USA
| | - Ligia Toro
- Department of Anesthesiology, University of California, Los Angeles Los Angeles, CA, USA ; Deparment of Molecular and Medical Pharmacology, University of California, Los Angeles Los Angeles, CA, USA ; Brain Research Institute, University of California, Los Angeles Los Angeles, CA, USA ; Cardiovascular Research Laboratory, University of California, Los Angeles Los Angeles, CA, USA
| |
Collapse
|
40
|
Xu H, Martinoia E, Szabo I. Organellar channels and transporters. Cell Calcium 2015; 58:1-10. [PMID: 25795199 DOI: 10.1016/j.ceca.2015.02.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 02/20/2015] [Indexed: 12/22/2022]
Abstract
Decades of intensive research have led to the discovery of most plasma membrane ion channels and transporters and the characterization of their physiological functions. In contrast, although over 80% of transport processes occur inside the cells, the ion flux mechanisms across intracellular membranes (the endoplasmic reticulum, Golgi apparatus, endosomes, lysosomes, mitochondria, chloroplasts, and vacuoles) are difficult to investigate and remain poorly understood. Recent technical advances in super-resolution microscopy, organellar electrophysiology, organelle-targeted fluorescence imaging, and organelle proteomics have pushed a large step forward in the research of intracellular ion transport. Many new organellar channels are molecularly identified and electrophysiologically characterized. Additionally, molecular identification of many of these ion channels/transporters has made it possible to study their physiological functions by genetic and pharmacological means. For example, organellar channels have been shown to regulate important cellular processes such as programmed cell death and photosynthesis, and are involved in many different pathologies. This special issue (SI) on organellar channels and transporters aims to provide a forum to discuss the recent advances and to define the standard and open questions in this exciting and rapidly developing field. Along this line, a new Gordon Research Conference dedicated to the multidisciplinary study of intracellular membrane transport proteins will be launched this coming summer.
Collapse
Affiliation(s)
- Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University Avenue, Ann Arbor, MI 48109-1048, USA.
| | - Enrico Martinoia
- Institute of Plant Biology, University of Zürich, Zollikerstr. 107, CH-8008 Zürich, Switzerland.
| | - Ildiko Szabo
- Department of Biology, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy; CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy.
| |
Collapse
|
41
|
Tao X, Lin MT, Thorington GU, Wilson SM, Longo LD, Hessinger DA. Long-term hypoxia increases calcium affinity of BK channels in ovine fetal and adult cerebral artery smooth muscle. Am J Physiol Heart Circ Physiol 2015; 308:H707-22. [PMID: 25599571 DOI: 10.1152/ajpheart.00564.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 01/14/2015] [Indexed: 01/31/2023]
Abstract
Acclimatization to high-altitude, long-term hypoxia (LTH) reportedly alters cerebral artery contraction-relaxation responses associated with changes in K(+) channel activity. We hypothesized that to maintain oxygenation during LTH, basilar arteries (BA) in the ovine adult and near-term fetus would show increased large-conductance Ca(2+) activated potassium (BK) channel activity. We measured BK channel activity, expression, and cell surface distribution by use of patch-clamp electrophysiology, flow cytometry, and confocal microscopy, respectively, in myocytes from normoxic control and LTH adult and near-term fetus BA. Electrophysiological data showed that BK channels in LTH myocytes exhibited 1) lowered Ca(2+) set points, 2) left-shifted activation voltages, and 3) longer dwell times. BK channels in LTH myocytes also appeared to be more dephosphorylated. These differences collectively make LTH BK channels more sensitive to activation. Studies using flow cytometry showed that the LTH fetus exhibited increased BK β1 subunit surface expression. In addition, in both fetal groups confocal microscopy revealed increased BK channel clustering and colocalization to myocyte lipid rafts. We conclude that increased BK channel activity in LTH BA occurred in association with increased channel affinity for Ca(2+) and left-shifted voltage activation. Increased cerebrovascular BK channel activity may be a mechanism by which LTH adult and near-term fetal sheep can acclimatize to long-term high altitude hypoxia. Our findings suggest that increasing BK channel activity in cerebral myocytes may be a therapeutic target to ameliorate the adverse effects of high altitude in adults or of intrauterine hypoxia in the fetus.
Collapse
Affiliation(s)
- Xiaoxiao Tao
- Division of Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Mike T Lin
- Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California; Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama
| | - Glyne U Thorington
- Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California
| | - Sean M Wilson
- Division of Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California; Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, California; and
| | - Lawrence D Longo
- Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California; Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, California; and
| | - David A Hessinger
- Division of Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California; Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, California;
| |
Collapse
|
42
|
Clements RT, Terentyev D, Sellke FW. Ca 2+-Activated K + Channels as Therapeutic Targets for Myocardial and Vascular Protection. Circ J 2015; 79:455-62. [DOI: 10.1253/circj.cj-15-0015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Richard T. Clements
- Department of Surgery, Cardiovascular Research Center, Cardiovascular Institute, Rhode Island Hospital and Alpert Medical School of Brown University
| | - Dmitry Terentyev
- Department of Medicine, Cardiovascular Research Center, Cardiovascular Institute, Rhode Island Hospital and Alpert Medical School of Brown University
| | - Frank W. Sellke
- Department of Surgery, Cardiovascular Research Center, Cardiovascular Institute, Rhode Island Hospital and Alpert Medical School of Brown University
| |
Collapse
|
43
|
Testai L, Rapposelli S, Martelli A, Breschi M, Calderone V. Mitochondrial Potassium Channels as Pharmacological Target for Cardioprotective Drugs. Med Res Rev 2014; 35:520-53. [DOI: 10.1002/med.21332] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- L. Testai
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - S. Rapposelli
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - A. Martelli
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - M.C. Breschi
- Department of Pharmacy; University of Pisa; Pisa Italy
| | - V. Calderone
- Department of Pharmacy; University of Pisa; Pisa Italy
| |
Collapse
|
44
|
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.
Collapse
|
45
|
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.
Collapse
|
46
|
Zhang L, Wang S, Dong H, Li Y, Wang P, Li S, Guo Y, Yao R. Spermine attenuates the preconditioning of diazoxide against transient focal cerebral ischemia in rats. Neurol Res 2013; 36:666-72. [PMID: 24620960 DOI: 10.1179/1743132813y.0000000299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
It is known that mitochondrial ATP-sensitive potassium channels (mitoKATP) play a significant role in protecting cerebral function from ischemia-reperfusion injury, which is related with a decrease in the mitochondrial matrix calcium. However, the effect of mitochondrial calcium uniporter (MCU) on diazoxide-induced cerebral protection is still indistinct. The purpose of the present paper is to further observe the relationship between mitoKATP and MCU, and to probe the mechanism. Adult male Wistar rats were randomly divided into five groups: the Sham group, the I-R group, the Dzx+I-R group, the Dzx+Sper+I-R group, and the Sper+I-R group. Rats not in the Sham group were exposed to 2-hour ischemia followed by 24-hour reperfusion. Diazoxide and spermine were administrated 30 minutes before ischemia or 10 minutes before reperfusion, respectively. After 24-hour reperfusion, animals were given neurological performance tests, overdosed with general anesthesia, and then their brains were excised for infarct volume, pathological changes, and apoptosis analysis. The beneficial effects of diazoxide (improved neurological deficits, decreased infarct volume, and apoptosis, evidenced by the decreased expression of cytochrome c and Bax) were significantly neutralized by spermine. The results of the present work suggest that diazoxide-induced cerebral protection against ischemia-reperfusion injury is mediated by spermine through apoptotic pathway.
Collapse
|
47
|
Belyaeva EA. Effect of diazoxide on AS-30D rat ascites hepatoma cells treated by Cd2+. J EVOL BIOCHEM PHYS+ 2013. [DOI: 10.1134/s0022093013050046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
48
|
Pasello G, Urso L, Conte P, Favaretto A. Effects of sulfonylureas on tumor growth: a review of the literature. Oncologist 2013; 18:1118-25. [PMID: 24043597 DOI: 10.1634/theoncologist.2013-0177] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Type 2 diabetes mellitus patients are at higher cancer risk, probably because of hyperinsulinemia and insulin growth factor 1 pathway activation. The effects of antidiabetic drugs on cancer risk have been described and discussed in several studies suggesting opposite effects of the biguanide metformin and sulfonylureas on cancer incidence and mortality. The anticancer mechanisms of metformin have been clarified, and some clinical studies, particularly in breast cancer patients, have been published or are currently ongoing; however, data about the effects of sulfonylureas on cancer growth are less consistent. The aims of this work are to review preclinical evidence of second-generation sulfonylureas effects on tumor growth, to clarify the potential mechanisms of action, and to identify possible metabolic targets for patient selection. Most evidence is on the adenosine triphosphate-sensitive potassium channels inhibitor glibenclamide, which interacts with reactive oxygen species production thus inducing cancer cell death. Among diarylsulfonylureas, next-generation DW2282 derivatives are particularly promising because of the proapoptotic activity in multidrug-resistant cells.
Collapse
Affiliation(s)
- Giulia Pasello
- Second Medical Oncology Unit, Istituto Oncologico Veneto, Padua, Italy
| | | | | | | |
Collapse
|
49
|
Kane DA, Pavlov EV. Calculation of ion currents across the inner membrane of functionally intact mitochondria. Channels (Austin) 2013; 7:426-31. [PMID: 24037064 DOI: 10.4161/chan.26290] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Mitochondrial ion transport systems play a central role in cell physiology. Rates of Ca (2+) and K(+) transport across the inner mitochondrial membrane have been derived from the measurement of ion accumulation over time within functional isolated mitochondria or mitochondria of cultured cells. Alternatively, the electrical currents generated by ionic flux have been directly measured in purified and swollen mitochondrial samples (mitoplasts) or reconstituted channels, and typically range from 1 pA to several 100s pA. However, the direct electrophysiological approach necessarily requires extensive processing of the mitochondria prior to measurement, which can only be performed on isolated mitoplasts. To compare rates of mitochondrial ion transport measured in electrophysiological experiments to those measured in intact mitochondria and cells, we converted published rates of mitochondrial ion uptake into units of ionic current. We estimate that for monovalent ions, uptake by intact mitochondria at the rate of 1 nmol ∙ mg(-1) protein ∙ min(-1) is equivalent to 0.2 fA of current per whole single mitochondrion (0.4 fA for divalent ions). In intact mitochondria, estimated rates of electrogenic cation uptake are limited to 1-100 fA of integral current per single mitochondrion. These estimates are orders of magnitude lower than the currents through mitochondrial channels directly measured via patch-clamp or artificial lipid bilayer approaches.
Collapse
Affiliation(s)
- Daniel A Kane
- Department of Human Kinetics; St. Francis Xavier University; Antigonish, Nova Scotia, Canada
| | - Evgeny V Pavlov
- Department of Physiology and Biophysics; Dalhousie University; Halifax, Nova Scotia, Canada
| |
Collapse
|
50
|
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.
Collapse
Affiliation(s)
- Anna Olszewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Warsaw, Poland.
| | | |
Collapse
|