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Wang J, Papanicolaou K, Tryon R, Sangalang J, Salazar B, Suarez-Pierre A, Dong J, Lee A, Larson E, Holmes S, O’Rourke B, Nichols C, Lawton J. Kir1.1 and SUR1 are not implicated as subunits of an adenosine triphosphate-sensitive potassium channel involved in diazoxide cardioprotection. JTCVS OPEN 2023; 15:231-241. [PMID: 37808059 PMCID: PMC10556815 DOI: 10.1016/j.xjon.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/29/2023] [Accepted: 06/06/2023] [Indexed: 10/10/2023]
Abstract
Objective The adenosine triphosphate-sensitive potassium channel opener diazoxide mimics ischemic preconditioning and is cardioprotective. Clarification of diazoxide's site and mechanism of action could lead to targeted pharmacologic therapies for patients undergoing cardiac surgery. Several mitochondrial candidate proteins have been investigated as potential adenosine triphosphate-sensitive potassium channel components. Renal outer medullary potassium (Kir1.1) and sulfonylurea sensitive regulatory subunit 1 have been suggested as subunits of a mitochondrial adenosine triphosphate-sensitive potassium channel. We hypothesized that pharmacologic blockade or genetic deletion (knockout) of renal outer medullary potassium and sensitive regulatory subunit 1 would result in loss of diazoxide cardioprotection in models of global ischemia with cardioplegia. Methods Myocyte volume and contractility were compared after Tyrode's physiologic solution (20 minutes), stress (hyperkalemic cardioplegia ± diazoxide, ± VU591 (Kir1.1 inhibitor), N = 9 to 23 each, 20 min), and Tyrode's (20 minutes). Isolated mouse (wild-type, sensitive regulatory subunit 1 [-/-], and cardiac knockout renal outer medullary potassium) hearts were given cardioplegia ± diazoxide (N = 9-16 each) before global ischemia (90 minutes) and 30 minutes reperfusion. Left ventricular pressures were compared before and after ischemia. Results Stress (cardioplegia) was associated with reduced myocyte contractility that was prevented by diazoxide. Isolated myocytes were not responsive to diazoxide in the presence of VU591. In isolated hearts, diazoxide improved left ventricular function after prolonged ischemia compared with cardioplegia alone in wild-type and knockout (sensitive regulatory subunit 1 [-/-] and cardiac knockout renal outer medullary potassium) mice. Conclusions Isolated myocyte and heart models may measure independent and separate actions of diazoxide. By definitive genetic deletion, these data indicate that sensitive regulatory subunit 1 and renal outer medullary potassium are not implicated in cardioprotection by diazoxide.
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Affiliation(s)
- Jie Wang
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
| | - Kyriakos Papanicolaou
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Md
| | - Robert Tryon
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Mo
| | - Janelle Sangalang
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
| | - Ben Salazar
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Md
| | | | - Jie Dong
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
| | - Anson Lee
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
| | - Emily Larson
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
| | - Sari Holmes
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
| | - Brian O’Rourke
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Md
| | - Colin Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Mo
| | - Jennifer Lawton
- Division of Cardiac Surgery, Department of Surgery, Johns Hopkins University, Baltimore, Md
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Juhaszova M, Kobrinsky E, Zorov DB, Nuss HB, Yaniv Y, Fishbein KW, de Cabo R, Montoliu L, Gabelli SB, Aon MA, Cortassa S, Sollott SJ. ATP Synthase K +- and H +-fluxes Drive ATP Synthesis and Enable Mitochondrial K +-"Uniporter" Function: II. Ion and ATP Synthase Flux Regulation. FUNCTION (OXFORD, ENGLAND) 2022; 3:zqac001. [PMID: 35187492 PMCID: PMC8850977 DOI: 10.1093/function/zqac001] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/12/2022] [Accepted: 01/18/2022] [Indexed: 01/07/2023]
Abstract
We demonstrated that ATP synthase serves the functions of a primary mitochondrial K+ "uniporter," i.e., the primary way for K+ to enter mitochondria. This K+ entry is proportional to ATP synthesis, regulating matrix volume and energy supply-vs-demand matching. We show that ATP synthase can be upregulated by endogenous survival-related proteins via IF1. We identified a conserved BH3-like domain of IF1 which overlaps its "minimal inhibitory domain" that binds to the β-subunit of F1. Bcl-xL and Mcl-1 possess a BH3-binding-groove that can engage IF1 and exert effects, requiring this interaction, comparable to diazoxide to augment ATP synthase's H+ and K+ flux and ATP synthesis. Bcl-xL and Mcl-1, but not Bcl-2, serve as endogenous regulatory ligands of ATP synthase via interaction with IF1 at this BH3-like domain, to increase its chemo-mechanical efficiency, enabling its function as the recruitable mitochondrial KATP-channel that can limit ischemia-reperfusion injury. Using Bayesian phylogenetic analysis to examine potential bacterial IF1-progenitors, we found that IF1 is likely an ancient (∼2 Gya) Bcl-family member that evolved from primordial bacteria resident in eukaryotes, corresponding to their putative emergence as symbiotic mitochondria, and functioning to prevent their parasitic ATP consumption inside the host cell.
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Affiliation(s)
| | | | | | | | | | - Kenneth W Fishbein
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Lluis Montoliu
- National Centre for Biotechnology (CNB-CSIC), Biomedical Research Networking Center on Rare Diseases (CIBERER-ISCIII), 28049 Madrid, Spain
| | - Sandra B Gabelli
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Sonia Cortassa
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD 21224, USA
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Mitochondrial proteomics alterations in rat hearts following ischemia/reperfusion and diazoxide post‑conditioning. Mol Med Rep 2020; 23:161. [PMID: 33355377 PMCID: PMC7789131 DOI: 10.3892/mmr.2020.11800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023] Open
Abstract
Diazoxide post-conditioning (D-Post) has been shown to be effective in alleviating myocardial ischemia/reperfusion (I/R) injury; however, the specific mechanisms are not fully understood. In the present study, isolated rat hearts were subjected to I/R injury and D-Post. The mitochondria were extracted, and mitochondrial protein expression was detected in normal, I/R and D-Post hearts using two-dimensional electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Differentially expressed proteins were then identified using comparative proteomics. In total, five differentially expressed proteins were identified between the I/R and D-Post hearts. Compared with the I/R hearts, the expression of NADH dehydrogenase (ubiquinone) flavoprotein 1 (NDUFV1), NADH-ubiquinone oxidoreductase 75 kDa subunit (NDUFS1), 2-oxoglutarate dehydrogenase (OGDH) and ATP synthase α subunit (isoform CRA_b, gi|149029482) was increased in D-Post hearts. In addition, the expression of another isoform of ATP synthase α subunit (isoform CRA_c, gi|149029480) was decreased in the D-Post group compared with the I/R group. The expression profiles of NDUFV1, NDUFS1 and OGDH in the two groups were further validated via western blotting. The five differentially expressed proteins may be protective effectors in D-Post, as well as potential targets for the treatment of cardiac I/R injury.
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ATP-sensitive potassium transport in rat brain mitochondria is highly sensitive to mK(ATP) channels openers: a light scattering study. UKRAINIAN BIOCHEMICAL JOURNAL 2020. [DOI: 10.15407/ubj92.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Fryer ML, Balsam LB. Commentary: Single-dose cardioplegia: Adjusting the brew. J Thorac Cardiovasc Surg 2020; 163:e403-e404. [PMID: 33008577 DOI: 10.1016/j.jtcvs.2020.09.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 11/27/2022]
Affiliation(s)
| | - Leora B Balsam
- Division of Cardiac Surgery, UMass Memorial Medical Center, Worcester, Mass.
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Akopova O, Kolchinskaya L, Nosar V, Mankovska I, Sagach V. Diazoxide affects mitochondrial bioenergetics by the opening of mKATP channel on submicromolar scale. BMC Mol Cell Biol 2020; 21:31. [PMID: 32306897 PMCID: PMC7168813 DOI: 10.1186/s12860-020-00275-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 04/07/2020] [Indexed: 12/21/2022] Open
Abstract
Background Cytoprotection afforded by mitochondrial ATP-sensitive K+-channel (mKATP-channel) opener diazoxide (DZ) largely depends on the activation of potassium cycle with eventual modulation of mitochondrial functions and ROS production. However, generally these effects were studied in the presence of Mg∙ATP known to block K+ transport. Thus, the purpose of our work was the estimation of DZ effects on K+ transport, K+ cycle and ROS production in rat liver mitochondria in the absence of Mg∙ATP. Results Without Mg·ATP, full activation of native mKATP-channel, accompanied by the increase in ATP-insensitive K+ uptake, activation of K+-cycle and respiratory uncoupling, was reached at ≤0.5 μM of DZ,. Higher diazoxide concentrations augmented ATP-insensitive K+ uptake, but not mKATP-channel activity. mKATP-channel was blocked by Mg·ATP, reactivated by DZ, and repeatedly blocked by mKATP-channel blockers glibenclamide and 5-hydroxydecanoate, whereas ATP-insensitive potassium transport was blocked by Mg2+ and was not restored by DZ. High sensitivity of potassium transport to DZ in native mitochondria resulted in suppression of mitochondrial ROS production caused by the activation of K+-cycle on sub-micromolar scale. Based on the oxygen consumption study, the share of mKATP-channel in respiratory uncoupling by DZ was found. Conclusions The study of mKATP-channel activation by diazoxide in the absence of MgATP discloses novel, not described earlier, aspects of mKATP-channel interaction with this drug. High sensitivity of mKATP-channel to DZ results in the modulation of mitochondrial functions and ROS production by DZ on sub-micromolar concentration scale. Our experiments led us to the hypothesis that under the conditions marked by ATP deficiency affinity of mKATP-channel to DZ can increase, which might contribute to the high effectiveness of this drug in cardio- and neuroprotection.
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Affiliation(s)
- Olga Akopova
- Circulation department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, Kiev, 01601, Ukraine.
| | - Liudmila Kolchinskaya
- Circulation department, Bogomoletz Institute of Physiology, NAS of Ukraine, Bogomoletz str. 4, Kiev, 01601, Ukraine
| | - Valentina Nosar
- Hypoxic States Research Department, Bogomoletz Institute of Physiology, NAS of Ukraine, 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, Kiev, 01601, Ukraine
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Papanicolaou KN, Ashok D, Liu T, Bauer TM, Sun J, Li Z, da Costa E, D'Orleans CC, Nathan S, Lefer DJ, Murphy E, Paolocci N, Foster DB, O'Rourke B. Global knockout of ROMK potassium channel worsens cardiac ischemia-reperfusion injury but cardiomyocyte-specific knockout does not: Implications for the identity of mitoKATP. J Mol Cell Cardiol 2020; 139:176-189. [PMID: 32004507 PMCID: PMC7849919 DOI: 10.1016/j.yjmcc.2020.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/16/2020] [Accepted: 01/23/2020] [Indexed: 01/29/2023]
Abstract
The renal-outer-medullary‑potassium (ROMK) channel, mutated in Bartter's syndrome, regulates ion exchange in kidney, but its extra-renal functions remain unknown. Additionally, ROMK was postulated to be the pore-forming subunit of the mitochondrial ATP-sensitive K+ channel (mitoKATP), a mediator of cardioprotection. Using global and cardiomyocyte-specific knockout mice (ROMK-GKO and ROMK-CKO respectively), we characterize the effects of ROMK knockout on mitochondrial ion handling, the response to pharmacological KATP channel modulators, and ischemia/reperfusion (I/R) injury. Mitochondria from ROMK-GKO hearts exhibited a lower threshold for Ca2+-triggered permeability transition pore (mPTP) opening but normal matrix volume changes during oxidative phosphorylation. Isolated perfused ROMK-GKO hearts exhibited impaired functional recovery and increased infarct size when I/R was preceded by an ischemic preconditioning (IPC) protocol. Because ROMK-GKO mice exhibited severe renal defects and cardiac remodeling, we further characterized ROMK-CKO hearts to avoid confounding systemic effects. Mitochondria from ROMK-CKO hearts had unchanged matrix volume responses during oxidative phosphorylation and still swelled upon addition of a mitoKATP opener, but exhibited a lower threshold for mPTP opening, similar to GKO mitochondria. Nevertheless, I/R induced damage was not exacerbated in ROMK-CKO hearts, either ex vivo or in vivo. Lastly, we examined the response of ROMK-CKO hearts to ex vivo I/R injury with or without IPC and found that IPC still protected these hearts, suggesting that cardiomyocyte ROMK does not participate significantly in the cardioprotective pathway elicited by IPC. Collectively, our findings from these novel strains of mice suggest that cardiomyocyte ROMK is not a central mediator of mitoKATP function, although it can affect mPTP activation threshold.
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Affiliation(s)
- Kyriakos N Papanicolaou
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Deepthi Ashok
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ting Liu
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tyler M Bauer
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Junhui Sun
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Zhen Li
- Cardiovascular Center of Excellence, Louisiana State University (LSU) Health Sciences Center, New Orleans, LA, USA; Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA, USA
| | - Eduardo da Costa
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Charles Crepy D'Orleans
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sara Nathan
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David J Lefer
- Cardiovascular Center of Excellence, Louisiana State University (LSU) Health Sciences Center, New Orleans, LA, USA; Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA, USA
| | - Elizabeth Murphy
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Shemarova IV, Nesterov VP, Korotkov SM, Sobol’ KV. Involvement of Ca2+ in the development of ischemic disorders of myocardial contractile function. J EVOL BIOCHEM PHYS+ 2017. [DOI: 10.1134/s0022093017050027] [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]
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9
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The therapeutic potential of targeting the K ir1.1 (renal outer medullary K +) channel. Future Med Chem 2017; 9:1963-1977. [PMID: 29076349 DOI: 10.4155/fmc-2017-0083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Kir1.1 (renal outer medullary K+) channels are potassium channels expressed almost exclusively in the kidney and play a role in the body's electrolyte and water balance. Potassium efflux through Kir1.1 compliments the role of transporters and sodium channels that are the targets of known diuretics. Consequently, loss-of-function mutations in men and rodents are associated with salt wasting and low blood pressure. On this basis, Kir1.1 inhibitors may have value in the treatment of hypertension and heart failure. Efforts to develop small molecule Kir1.1 inhibitors produced MK-7145, which entered into clinical trials. The present manuscript describes the structure-activity relationships associated with this scaffold alongside other preclinical Kir1.1 blockers.
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10
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Effects of remote ischemic preconditioning on acute myocardial injury in patients undergoing valve replacement. Ir J Med Sci 2016; 186:889-893. [DOI: 10.1007/s11845-016-1521-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 10/21/2016] [Indexed: 12/15/2022]
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Henn MC, Janjua MB, Zhang H, Kanter EM, Makepeace CM, Schuessler RB, Nichols CG, Lawton JS. Increased tolerance to stress in cardiac expressed gain-of-function of adenosine triphosphate-sensitive potassium channel subunit Kir6.1. J Surg Res 2016; 206:460-465. [PMID: 27884343 DOI: 10.1016/j.jss.2016.08.043] [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] [Received: 04/30/2016] [Revised: 06/22/2016] [Accepted: 08/05/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND The adenosine triphosphate-sensitive potassium (KATP) channel opener diazoxide (DZX) prevents myocyte volume derangement and reduced contractility secondary to stress. KATP channels are composed of pore-forming (Kir6.1 or Kir6.2) and regulatory (sulfonylurea receptor, SUR1 or SUR2) subunits. Gain of function (GOF) of Kir6.1 subunits has been implicated in cardiac pathology in Cantu syndrome in humans (cardiomegaly, lymphedema, and pericardial effusions). We hypothesized that GOF of Kir6.1 subunits would result in altered myocyte response to stress. MATERIALS AND METHODS Isolated cardiac myocytes from wild type (WT) and transgenic Kir6.1GOF mice were exposed to Tyrode's physiologic solution for 20 min, test solution (Tyrode's or stress [hyperkalemic cardioplegia {CPG, known myocyte stress}] +/- KATP channel opener DZX), followed by Tyrode's for 20 min. Myocyte volume and contractility were measured and compared. RESULTS WT myocytes demonstrated significant swelling in response to stress, but significantly less swelling was seen in Kir6.1GOF myocytes. DZX prevented swelling secondary to CPG in WT but resulted in a nonsignificant reduction in swelling in Kir6.1GOF myocytes. Both WT and Kir6.1GOF myocytes demonstrated a reduction in contractility during stress, although this was only significant in Kir6.1GOF myocytes. DZX was not associated with an improvement in contractility in Kir6.1GOF myocytes following stress. CONCLUSIONS Similar to previous results in Kir6.1(-/-) myocytes, Kir6.1GOF myocytes demonstrate resistance (less volume derangement) to stress of cardioplegia. Understanding the role of Kir6.1 in myocyte response to stress may aid in the treatment of patients with Cantu syndrome and warrants further investigation.
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Affiliation(s)
- Matthew C Henn
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - M Burhan Janjua
- Department of Neurological Surgery, Weill Cornell Medical College, New York, New York
| | - Haixia Zhang
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | - Evelyn M Kanter
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Carol M Makepeace
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Richard B Schuessler
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | - Jennifer S Lawton
- Division of Cardiothoracic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri.
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Martínez-Moreno M, Batlle M, Ortega FJ, Gimeno-Bayón J, Andrade C, Mahy N, Rodríguez MJ. Diazoxide enhances excitotoxicity-induced neurogenesis and attenuates neurodegeneration in the rat non-neurogenic hippocampus. Neuroscience 2016; 333:229-43. [PMID: 27471195 DOI: 10.1016/j.neuroscience.2016.07.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 12/13/2022]
Abstract
Diazoxide, a well-known mitochondrial KATP channel opener with neuroprotective effects, has been proposed for the effective and safe treatment of neuroinflammation. To test whether diazoxide affects the neurogenesis associated with excitotoxicity in brain injury, we induced lesions by injecting excitotoxic N-methyl-d-aspartate (NMDA) into the rat hippocampus and analyzed the effects of a daily oral administration of diazoxide on the induced lesion. Specific glial and neuronal staining showed that NMDA elicited a strong glial reaction associated with progressive neuronal loss in the whole hippocampal formation. Doublecortin immunohistochemistry and bromo-deoxyuridine (BrdU)-NeuN double immunohistochemistry revealed that NMDA also induced cell proliferation and neurogenesis in the lesioned non-neurogenic hippocampus. Furthermore, glial fibrillary acidic protein (GFAP)-positive cells in the injured hippocampus expressed transcription factor Sp8 indicating that the excitotoxic lesion elicited the migration of progenitors from the subventricular zone and/or the reprograming of reactive astrocytes. Diazoxide treatment attenuated the NMDA-induced hippocampal injury in rats, as demonstrated by decreases in the size of the lesion, neuronal loss and microglial reaction. Diazoxide also increased the number of BrdU/NeuN double-stained cells and elevated the number of Sp8-positive cells in the lesioned hippocampus. These results indicate a role for KATP channel activation in regulating excitotoxicity-induced neurogenesis in brain injury.
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Affiliation(s)
- M Martínez-Moreno
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - M Batlle
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - F J Ortega
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - J Gimeno-Bayón
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - C Andrade
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - N Mahy
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - M J Rodríguez
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain.
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Laskowski M, Augustynek B, Kulawiak B, Koprowski P, Bednarczyk P, Jarmuszkiewicz W, Szewczyk A. What do we not know about mitochondrial potassium channels? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1247-1257. [PMID: 26951942 DOI: 10.1016/j.bbabio.2016.03.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 01/14/2023]
Abstract
In this review, we summarize our knowledge about mitochondrial potassium channels, with a special focus on unanswered questions in this field. The following potassium channels have been well described in the inner mitochondrial membrane: ATP-regulated potassium channel, Ca(2+)-activated potassium channel, the voltage-gated Kv1.3 potassium channel, and the two-pore domain TASK-3 potassium channel. The primary functional roles of these channels include regulation of mitochondrial respiration and the alteration of membrane potential. Additionally, they modulate the mitochondrial matrix volume and the synthesis of reactive oxygen species by mitochondria. Mitochondrial potassium channels are believed to contribute to cytoprotection and cell death. In this paper, we discuss fundamental issues concerning mitochondrial potassium channels: their molecular identity, channel pharmacology and functional properties. Attention will be given to the current problems present in our understanding of the nature of mitochondrial potassium channels. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Michał Laskowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Bartłomiej Augustynek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Biophysics, Warsaw University of Life Sciences - SGGW, 159 Nowoursynowska St., 02-776 Warsaw, Poland
| | - Wieslawa Jarmuszkiewicz
- Laboratory of Bioenergetics, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Adam Szewczyk
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
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Ruel M. Cardiovascular Surgery Supplement. Circulation 2015; 132:719. [PMID: 26304662 DOI: 10.1161/circulationaha.115.018604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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