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Hoogstraten CA, Schirris TJJ, Russel FGM. Unlocking mitochondrial drug targets: The importance of mitochondrial transport proteins. Acta Physiol (Oxf) 2024; 240:e14150. [PMID: 38666512 DOI: 10.1111/apha.14150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/02/2024] [Accepted: 04/12/2024] [Indexed: 05/12/2024]
Abstract
A disturbed mitochondrial function contributes to the pathology of many common diseases. These organelles are therefore important therapeutic targets. On the contrary, many adverse effects of drugs can be explained by a mitochondrial off-target effect, in particular, due to an interaction with carrier proteins in the inner membrane. Yet this class of transport proteins remains underappreciated and understudied. The aim of this review is to provide a deeper understanding of the role of mitochondrial carriers in health and disease and their significance as drug targets. We present literature-based evidence that mitochondrial carrier proteins are associated with prevalent diseases and emphasize their potential as drug (off-)target sites by summarizing known mitochondrial drug-transporter interactions. Studying these carriers will enhance our knowledge of mitochondrial drug on- and off-targets and provide opportunities to further improve the efficacy and safety of drugs.
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Affiliation(s)
- Charlotte A Hoogstraten
- Department of Pharmacy, Division of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Tom J J Schirris
- Department of Pharmacy, Division of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans G M Russel
- Department of Pharmacy, Division of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
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2
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Escudero DS, Pérez NG, Díaz RG. Myocardial Impact of NHE1 Regulation by Sildenafil. Front Cardiovasc Med 2021; 8:617519. [PMID: 33693035 PMCID: PMC7937606 DOI: 10.3389/fcvm.2021.617519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/04/2021] [Indexed: 11/13/2022] Open
Abstract
The cardiac Na+/H+ exchanger (NHE1) is a membrane glycoprotein fundamental for proper cell functioning due its multiple housekeeping tasks, including regulation of intracellular pH, Na+ concentration, and cell volume. In the heart, hyperactivation of NHE1 has been linked to the development of different pathologies. Several studies in animal models that reproduce the deleterious effects of ischemia/reperfusion injury or cardiac hypertrophy have conclusively demonstrated that NHE1 inhibition provides cardioprotection. Unfortunately, NHE1 inhibitors failed to reproduce these effects in the clinical arena. The reasons for those discrepancies are not apparent yet. However, a reasonable clue to consider would be that drugs that completely abolish the exchanger activity, including that its essential housekeeping function may not be the best therapeutic approach. Therefore, interventions tending to specifically reduce its hyperactive state without affecting its basal activity emerge as a novel potential gold standard. In this regard, a promising goal seems to be the modulation of the phosphorylation state of the cytosolic tail of the exchanger. Recent own experiments demonstrated that Sildenafil, a phosphodiesterase 5A inhibitor drug that has been widely used for the treatment of erectile dysfunction is able to decrease NHE1 phosphorylation, and hence reduce its hyperactivity. In connection, growing evidence demonstrates cardioprotective properties of Sildenafil against different cardiac pathologies, with the distinctive characteristic of directly affecting cardiac tissue without altering blood pressure. This mini-review was aimed to focus on the regulation of NHE1 activity by Sildenafil. For this purpose, experimental data reporting Sildenafil effects in different animal models of heart disease will be discussed.
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Affiliation(s)
- Daiana S Escudero
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Néstor G Pérez
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Romina G Díaz
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
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Escudero DS, Brea MS, Caldiz CI, Amarillo ME, Aranda JO, Portiansky EL, Pérez NG, Díaz RG. PDE5 inhibition improves cardiac morphology and function in SHR by reducing NHE1 activity: Repurposing Sildenafil for the treatment of hypertensive cardiac hypertrophy. Eur J Pharmacol 2021; 891:173724. [PMID: 33152335 DOI: 10.1016/j.ejphar.2020.173724] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 01/16/2023]
Abstract
Previously, we have shown that an increased cGMP-activated protein Kinase (PKG) activity after phosphodiesterase 5 (PDE5) inhibition by Sildenafil (SIL), leads to myocardial Na+/H+ exchanger (NHE1) inhibition preserving its basal homeostatic function. Since NHE1 is hyperactive in the hypertrophied myocardium of spontaneous hypertensive rats (SHR), while its inhibition was shown to prevent and revert this pathology, the current study was aimed to evaluate the potential antihypertrophic effect of SIL on adult SHR myocardium. We initially tested the inhibitory capability of SIL on NHE1 in isolated cardiomyocytes of SHR by comparing H+ efflux during the recovery from an acid load. After confirmed that effect, eight-month-old SHR were chronically treated for one month with SIL through drinking water. Compared to their littermate controls, SIL-treated rats presented a decreased NHE1 activity, which correlated with a reduction in its phosphorylation level assigned to activation of a PKG-p38 MAP kinase-PP2A signaling pathway. Moreover, treated animals showed a decreased oxidative stress that appears to be a consequence of a decreased mitochondrial NHE1 phosphorylation. Treated SHR showed a significant reduction in the pro-hypertrophic phosphatase calcineurin, despite slight tendency to decrease hypertrophy was detected. When SIL treatment was prolonged to three months, a significant decrease in myocardial hypertrophy and interstitial fibrosis that correlated with a lower myocardial stiffness was observed. In conclusion, the current study provides evidence concerning the ability of SIL to revert established cardiac hypertrophy in SHR, a clinically relevant animal model that resembles human essential hypertension.
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Affiliation(s)
- Daiana S Escudero
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - María S Brea
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - Claudia I Caldiz
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - María E Amarillo
- Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina
| | - Jorge O Aranda
- Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina
| | - Enrique L Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Argentina
| | - Néstor G Pérez
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina
| | - Romina G Díaz
- Centro de Investigaciones Cardiovasculares "Dr. Horacio E. Cingolani", Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900 La Plata, Argentina.
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Ghaleh B, Barthélemy I, Wojcik J, Sambin L, Bizé A, Hittinger L, Tran TD, Thomé FP, Blot S, Su JB. Protective effects of rimeporide on left ventricular function in golden retriever muscular dystrophy dogs. Int J Cardiol 2020; 312:89-95. [PMID: 32199683 DOI: 10.1016/j.ijcard.2020.03.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/24/2020] [Accepted: 03/11/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Alterations in intracellular Na+ and Ca2+ have been observed in patients with Duchenne muscular dystrophy (DMD) and in animal models of DMD, and inhibition of Na+-H+ exchanger 1 (NHE1) by rimeporide has previously demonstrated cardioprotective effects in animal models of myocardial ischemia and heart failure. Since heart failure is becoming a predominant cause of death in DMD patients, this study aimed to demonstrate a cardioprotective effect of chronic administration of rimeporide in a canine model of DMD. METHODS Golden retriever muscular dystrophy (GRMD) dogs were randomized to orally receive rimeporide (10 mg/kg, twice a day) or placebo from 2 months to 1 year of age. Left ventricular (LV) function was assessed by conventional and advanced echocardiography. RESULTS Compared with placebo-treated GRMD, LV function deterioration with age was limited in rimeporide-treated GRMD dogs as indicated by the preservation of LV ejection fraction as well as overall cardiac parameters different from placebo-treated dogs, as revealed by composite cardiac scores and principal component analysis. In addition, principal component analysis clustered rimeporide-treated GRMD dogs close to healthy control dogs. CONCLUSIONS Chronic administration of the NHE1 inhibitor rimeporide exerted a protective effect against LV function decline in GRMD dogs. This study provides proof of concept to explore the cardiac effects of rimeporide in DMD patients.
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Affiliation(s)
- Bijan Ghaleh
- U955-IMRB, Equipe 03, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Inès Barthélemy
- U955-IMRB, Equipe 10, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Jérôme Wojcik
- Translational Informatics & Biometrics Europe, Precision for Medicine, CH-1202 Geneva, Switzerland
| | - Lucien Sambin
- U955-IMRB, Equipe 03, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Alain Bizé
- U955-IMRB, Equipe 03, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Luc Hittinger
- U955-IMRB, Equipe 10, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France; AP-HP, Hôpitaux Universitaires Henri Mondor, Fédération de Cardiologie, F-94000 Créteil, France
| | - Thien Duc Tran
- EspeRare, Campus Biotech Innovation Park, Avenue de Secheron 15, 1202 Geneva, Switzerland
| | - Florence Porte Thomé
- EspeRare, Campus Biotech Innovation Park, Avenue de Secheron 15, 1202 Geneva, Switzerland
| | - Stéphane Blot
- U955-IMRB, Equipe 10, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Jin Bo Su
- U955-IMRB, Equipe 03, Inserm, UPEC, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France.
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Lagadic-Gossmann D, Hardonnière K, Mograbi B, Sergent O, Huc L. Disturbances in H + dynamics during environmental carcinogenesis. Biochimie 2019; 163:171-183. [PMID: 31228544 DOI: 10.1016/j.biochi.2019.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 06/16/2019] [Indexed: 12/24/2022]
Abstract
Despite the improvement of diagnostic methods and anticancer therapeutics, the human population is still facing an increasing incidence of several types of cancers. According to the World Health Organization, this growing trend would be partly linked to our environment, with around 20% of cancers stemming from exposure to environmental contaminants, notably chemicals like polycyclic aromatic hydrocarbons (PAHs). PAHs are widespread pollutants in our environment resulting from incomplete combustion or pyrolysis of organic material, and thus produced by both natural and anthropic sources; notably benzo[a]pyrene (B[a]P), i.e. the prototypical molecule of this family, that can be detected in cigarette smoke, diesel exhaust particles, occupational-related fumes, and grilled food. This molecule is a well-recognized carcinogen belonging to group 1 carcinogens. Indeed, it can target the different steps of the carcinogenic process and all cancer hallmarks. Interestingly, H+ dynamics have been described as key parameters for the occurrence of several, if not all, of these hallmarks. However, information regarding the role of such parameters during environmental carcinogenesis is still very scarce. The present review will thus mainly give an overview of the impact of B[a]P on H+ dynamics in liver cells, and will show how such alterations might impact different aspects related to the finely-tuned balance between cell death and survival processes, thereby likely favoring environmental carcinogenesis. In total, the main objective of this review is to encourage further research in this poorly explored field of environmental molecular toxicology.
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Affiliation(s)
- Dominique Lagadic-Gossmann
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France.
| | - Kévin Hardonnière
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France
| | - Baharia Mograbi
- Institute of Research on Cancer and Ageing of Nice (IRCAN), INSERM U1081, CNRS UMR7284, 2. Université de Nice-Sophia Antipolis, Faculté de Médecine, Centre Antoine Lacassagne, Nice, F-06107, France
| | - Odile Sergent
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail), UMR_S 1085, F-35000, Rennes, France
| | - Laurence Huc
- INRA, ToxAlim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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Zhao RZ, Jiang S, Ru NY, Jiao B, Yu ZB. Comparison of hypoxic effects induced by chemical and physical hypoxia on cardiomyocytes. Can J Physiol Pharmacol 2019; 97:980-988. [PMID: 31136722 DOI: 10.1139/cjpp-2019-0092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The degree and duration of chemical hypoxia induced by sodium dithionite (Na2S2O4) have not been reported. It is not yet clear how much reduction in the O2 concentration (physical hypoxia) can lead to hypoxia in cultured cardiomyocytes. In this study, oxygen microelectrodes were used to measure changes in the O2 concentration in media containing different concentrations of Na2S2O4. Then, hypoxic effects of 0.8, 1.0, and 2.0 mM Na2S2O4 or 1%, 3%, and 5% O2 in cultured cardiomyocytes from neonatal rats were observed and compared. The results showed that the O2 concentration failed to remain constant by Na2S2O4 treatment during the 180-minute observation period. Only the 2.0 mM Na2S2O4 group significantly increased the expression of hypoxia-inducible factor 1α (HIF-1α) and hypoxic responses. Notably, 3% O2 only significantly increased the expression of HIF-1α in cardiomyocytes, while 1% O2 not only increased the expression of HIF-1α but also increased the apoptotic rate in cardiomyocytes. These results suggest that Na2S2O4 is not suitable for establishing a hypoxic model in cultured neonatal rat cardiomyocytes, and neonatal rat cardiomyocytes cultured at or below 1% O2 induced significant hypoxic effects, which can be used as a starting O2 concentration for establishing a hypoxic cell model.
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Affiliation(s)
- Ru-Zhou Zhao
- Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China
| | - Shuai Jiang
- Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China
| | - Ning-Yu Ru
- Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China.,Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China
| | - Bo Jiao
- Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China.,Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China
| | - Zhi-Bin Yu
- Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China.,Department of Aerospace Physiology, Fourth Military Medical University, Key Laboratory of Aerospace Medicine, Ministry of China, Xi'an 710032, China
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7
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Silencing of the Na+/H+ exchanger 1(NHE-1) prevents cardiac structural and functional remodeling induced by angiotensin II. Exp Mol Pathol 2019; 107:1-9. [DOI: 10.1016/j.yexmp.2019.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/08/2019] [Accepted: 01/16/2019] [Indexed: 12/30/2022]
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Wei L, Zhao W, Hu Y, Wang X, Liu X, Zhang P, Han F. Exploration of the optimal dose of HOE-642 for the protection of neuronal mitochondrial function after cardiac arrest in rats. Biomed Pharmacother 2018; 110:818-824. [PMID: 30554120 DOI: 10.1016/j.biopha.2018.12.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/03/2018] [Accepted: 12/07/2018] [Indexed: 11/28/2022] Open
Abstract
INTRODUCTION It has been demonstrated HOE-642 ameliorates ischemic contracture, prevents post-resuscitation diastolic dysfunction, and favors the earlier return of contractile function. This study is the first report to explore the optimal dose of HOE-642 in protecting the neuronal mitochondrial function after cardiac arrest. METHODS Cardiac arrest was induced by 8 min asphyxia in rats. There were Sham (S), Normothermic (NORM), and Hypothermic (HYPO) groups. The NORM or HYPO groups consist of four subgroups: NORM/HYPO + HOE-642 0, 1, 3, and 5 mg/kg. Survival and NDS were evaluated after 24 h of resuscitation. ΔΨm, mitochondrial swelling, ROS production, and mitochondrial complex IIV activity of the hippocampus were detected. RESULTS Survival in the HYPO + 1 mg group was the best and significantly higher than in the NORM + 0 mg and NORM + 1 mg groups. NDS in the HYPO + 0 mg, HYPO + 1 mg, and HYPO + 3 mg groups was significantly lower than in the NORM + 0 mg group. ΔΨm in the NORM + 1 mg (n = 5) group was significantly higher than in the NORM + 0 mg (n = 8), NORM + 3 mg (n = 5), and NORM + 5 mg (n = 5) groups. The ROS production in the NORM + 1 mg and NORM + 3 mg groups were significantly lower than in the NORM + 0 mg and NORM + 5 mg groups. Complex I and III activities in the HYPO + 1 mg (n = 5) group were significantly higher than in the HYPO + 3 mg (n = 5), and HYPO + 5 mg (n = 5) groups. Complex II and IV activities in the NORM + 3 mg and HYPO + 3 mg groups were significantly higher than in the NORM + 0 mg, NORM + 1 mg, and HYPO + 0 mg (n = 4)groups. CONCLUSIONS HOE-642 1 or 3 mg/kg showed benefits compared to HOE-642 5 mg/kg used when initiating resuscitation. When combined with hypothermia after cardiac arrest, HOE-642 1 or 3 mg/kg improved survival and neurological function compared with hypothermia or HOE-642 alone, however, HOE-642 5 mg/kg plus hypothermia did not.
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Affiliation(s)
- Lanying Wei
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Wenshuai Zhao
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Yanan Hu
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Xifan Wang
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Xintong Liu
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Pengjiao Zhang
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China
| | - Fei Han
- Department of Anesthesiology, The Third Affiliated Hospital, Harbin Medical University, Harbin, 150081, Heilongjiang, China.
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Ciocci Pardo A, Díaz RG, González Arbeláez LF, Pérez NG, Swenson ER, Mosca SM, Alvarez BV. Benzolamide perpetuates acidic conditions during reperfusion and reduces myocardial ischemia-reperfusion injury. J Appl Physiol (1985) 2017; 125:340-352. [PMID: 29357509 DOI: 10.1152/japplphysiol.00957.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
During ischemia, increased anaerobic glycolysis results in intracellular acidosis. Activation of alkalinizing transport mechanisms associated with carbonic anhydrases (CAs) leads to myocardial intracellular Ca2+ increase. We characterize the effects of inhibition of CA with benzolamide (BZ) during cardiac ischemia-reperfusion (I/R). Langendorff-perfused isolated rat hearts were subjected to 30 min of global ischemia and 60 min of reperfusion. Other hearts were treated with BZ (5 μM) during the initial 10 min of reperfusion or perfused with acid solution (AR, pH 6.4) during the first 3 min of reperfusion. p38MAPK, a kinase linked to membrane transporters and involved in cardioprotection, was examined in hearts treated with BZ in presence of the p38MAPK inhibitor SB202190 (10 μM). Infarct size (IZ) and myocardial function were assessed, and phosphorylated forms of p38MAPK, Akt, and PKCε were evaluated by immunoblotting. We determined the rate of intracellular pH (pHi) normalization after transient acid loading in the absence and presence of BZ or BZ + SB202190 in heart papillary muscles (HPMs). Mitochondrial membrane potential (ΔΨm), Ca2+ retention capacity and Ca2+-mediated swelling after I/R were also measured. BZ, similarly to AR, reduced IZ, improved postischemic recovery of myocardial contractility, increased phosphorylation of Akt, PKCε, and p38MAPK, and normalized ΔΨm and Ca2+ homeostasis, effects abolished after p38MAPK inhibition. In HPMs, BZ slowed pHi recovery, an effect that was restored after p38MAPK inhibition. We conclude that prolongation of acidic conditions during reperfusion by BZ could be responsible for the cardioprotective benefits of reduced infarction and better myocontractile function, through p38MAPK-dependent pathways. NEW & NOTEWORTHY Carbonic anhydrase inhibition by benzolamide (BZ) maintains acidity, decreases infarct size, and improves postischemic myocardial dysfunction in ischemia-reperfusion (I/R) hearts. Protection afforded by BZ mimicked the beneficial effects elicited by an acidic solution (AR). Increased phosphorylation of p38MAPK occurs in I/R hearts reperfused with BZ or with AR. Mitochondria from I/R hearts possess abnormal Ca2+ handling and a more depolarized membrane potential compared with control hearts, and these changes were restored by treatment with BZ or AR.
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Affiliation(s)
- Alejandro Ciocci Pardo
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Romina G Díaz
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Luisa F González Arbeláez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Néstor G Pérez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Erik R Swenson
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington, Department of Veterans Affairs Puget Sound Health Care System , Seattle, Washington
| | - Susana M Mosca
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Bernardo V Alvarez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
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10
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Javadov S, Chapa-Dubocq X, Makarov V. Different approaches to modeling analysis of mitochondrial swelling. Mitochondrion 2017; 38:58-70. [PMID: 28802667 DOI: 10.1016/j.mito.2017.08.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/21/2017] [Accepted: 08/08/2017] [Indexed: 12/11/2022]
Abstract
Mitochondria are critical players involved in both cell life and death through multiple pathways. Structural integrity, metabolism and function of mitochondria are regulated by matrix volume due to physiological changes of ion homeostasis in cellular cytoplasm and mitochondria. Ca2+ and K+ presumably play a critical role in physiological and pathological swelling of mitochondria when increased uptake (influx)/decreased release (efflux) of these ions enhances osmotic pressure accompanied by high water accumulation in the matrix. Changes in the matrix volume in the physiological range have a stimulatory effect on electron transfer chain and oxidative phosphorylation to satisfy metabolic requirements of the cell. However, excessive matrix swelling associated with the sustained opening of mitochondrial permeability transition pores (PTP) and other PTP-independent mechanisms compromises mitochondrial function and integrity leading to cell death. The mechanisms of transition from reversible (physiological) to irreversible (pathological) swelling of mitochondria remain unknown. Mitochondrial swelling is involved in the pathogenesis of many human diseases such as neurodegenerative and cardiovascular diseases. Therefore, modeling analysis of the swelling process is important for understanding the mechanisms of cell dysfunction. This review attempts to describe the role of mitochondrial swelling in cell life and death and the main mechanisms involved in the maintenance of ion homeostasis and swelling. The review also summarizes and discusses different kinetic models and approaches that can be useful for the development of new models for better simulation and prediction of in vivo mitochondrial swelling.
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Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA.
| | - Xavier Chapa-Dubocq
- Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA
| | - Vladimir Makarov
- Department of Physics, Rio Piedras Campus, University of Puerto Rico, San Juan, PR, USA
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11
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Vargas LA, Velasquez FC, Alvarez BV. RETRACTED ARTICLE: Compensatory role of the NBCn1 sodium/bicarbonate cotransporter on Ca2+-induced mitochondrial swelling in hypertrophic hearts. Basic Res Cardiol 2017; 112:14. [DOI: 10.1007/s00395-017-0604-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/20/2017] [Indexed: 11/28/2022]
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12
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Hardonnière K, Huc L, Sergent O, Holme JA, Lagadic-Gossmann D. Environmental carcinogenesis and pH homeostasis: Not only a matter of dysregulated metabolism. Semin Cancer Biol 2017; 43:49-65. [PMID: 28088583 DOI: 10.1016/j.semcancer.2017.01.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 12/18/2022]
Abstract
According to the World Health Organization, around 20% of all cancers would be due to environmental factors. Among these factors, several chemicals are indeed well recognized carcinogens. The widespread contaminant benzo[a]pyrene (B[a]P), an often used model carcinogen of the polycyclic aromatic hydrocarbons' family, has been suggested to target most, if not all, cancer hallmarks described by Hanahan and Weinberg. It is classified as a group I carcinogen by the International Agency for Research on Cancer; however, the precise intracellular mechanisms underlying its carcinogenic properties remain yet to be thoroughly defined. Recently, the pH homeostasis, a well known regulator of carcinogenic processes, was suggested to be a key actor in both cell death and Warburg-like metabolic reprogramming induced upon B[a]P exposure. The present review will highlight those data with the aim of favoring research on the role of H+ dynamics in environmental carcinogenesis.
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Affiliation(s)
- Kévin Hardonnière
- Institut national de la santé et de la recherche médicale (Inserm), Institut de recherche en santé, environnement et travail (Irset - Inserm UMR 1085), F-35043 Rennes, France; Université de Rennes 1, Structure fédérative de recherche Biosit, UMS CNRS 3480/US Inserm 018, F 35043 Rennes, France
| | - Laurence Huc
- INRA UMR 1331 ToxAlim (Research Center in Food Toxicology), University of Toulouse ENVT, INP, UPS, 180 Chemin de Tournefeuille, F-31027, France
| | - Odile Sergent
- Institut national de la santé et de la recherche médicale (Inserm), Institut de recherche en santé, environnement et travail (Irset - Inserm UMR 1085), F-35043 Rennes, France; Université de Rennes 1, Structure fédérative de recherche Biosit, UMS CNRS 3480/US Inserm 018, F 35043 Rennes, France
| | - Jørn A Holme
- Domain of Infection Control, Environment and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Dominique Lagadic-Gossmann
- Institut national de la santé et de la recherche médicale (Inserm), Institut de recherche en santé, environnement et travail (Irset - Inserm UMR 1085), F-35043 Rennes, France; Université de Rennes 1, Structure fédérative de recherche Biosit, UMS CNRS 3480/US Inserm 018, F 35043 Rennes, France.
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13
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Popov LD. Mitochondrial networking in diabetic left ventricle cardiomyocytes. Mitochondrion 2016; 34:24-31. [PMID: 28007605 DOI: 10.1016/j.mito.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 10/07/2016] [Accepted: 12/16/2016] [Indexed: 12/17/2022]
Abstract
Cardiomyocyte mitochondria preserve "the quorum sensing" attribute of their aerobic bacterial ancestors, as shown by the transient physical connectivity and communication not only with each other, but also with other intracellular organelles and with cytosol, ensuing cellular homeostasis. In this review, we present original electron microscopy evidence on mitochondrial networking within diabetic left ventricular cardiomyocytes, focusing on: (i) the inter-mitochondrial communication, allowing electrochemical signals transfer and outer membrane components or matrix proteins exchange, (ii) the interplay between mitochondria and the cardiomyocyte nucleus, nucleolus, sarcoplasmic reticulum, lysosomes, and lipid droplets viewed as attributes of mitochondrial "quality control" and "retrograde signaling function", and (iii) the crosstalk between mitochondria and cardiomyocyte cytosol, as part of the adaptive responses that allow cells survival. Confirmation of such interactions in diabetic myocardium and identification of molecules involved are ongoing, foreseeing the alleviation of heart contractile dysfunction in cardiomyopathy.
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Affiliation(s)
- Lucia-Doina Popov
- "Nicolae Simionescu" Institute of Cellular Biology and Pathology of the Romanian Academy, 8, B.P. Hasdeu Street, Bucharest 050568, Romania.
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14
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Abstract
Heart failure (HF) is a multifactorial disease brought about by numerous, and oftentimes complex, etiological mechanisms. Although well studied, HF continues to affect millions of people worldwide and current treatments can only prevent further progression of HF. Mitochondria undoubtedly play an important role in the progression of HF, and numerous studies have highlighted mitochondrial components that contribute to HF. This review presents an overview of the role of mitochondrial biogenesis, mitochondrial oxidative stress, and mitochondrial permeability transition pore in HF, discusses ongoing studies that attempt to address the disease through mitochondrial targeting, and provides an insight on how these studies can affect future research on HF treatment.
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15
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Cao J, Xie H, Sun Y, Zhu J, Ying M, Qiao S, Shao Q, Wu H, Wang C. Sevoflurane post-conditioning reduces rat myocardial ischemia reperfusion injury through an increase in NOS and a decrease in phopshorylated NHE1 levels. Int J Mol Med 2015; 36:1529-37. [PMID: 26459736 PMCID: PMC4678156 DOI: 10.3892/ijmm.2015.2366] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 09/24/2015] [Indexed: 12/22/2022] Open
Abstract
The protective effects of sevoflurane post-conditioning against myocardial ischemia/reperfusion (I/R) injury (MIRI) have been previously reported. However, the mechanisms responsible for these protective effects remain elusive. In this study, in order to investigate the molecular mechanisms responsible for the protective effects of sevoflurane post-conditioning on isolated rat hearts subjected to MIRI, Sprague-Dawley rat hearts were randomly divided into the following 6 groups: i) the sham-operated control; ii) 2.5% sevoflurane; iii) ischemia/reperfusion (I/R); iv) 2.5% sevoflurane post-conditioning plus I/R; v) 2.5% sevoflurane post-conditioning + NG-nitro-L-arginine methyl ester (L-NAME) plus I/R; and vi) L-NAME plus I/R. The infarct size was measured using 2,3,5-triphenyl tetrazolium chloride (TTC) staining. Additionally, the myocardial nitric oxide (NO), NO synthase (NOS) and nicotinamide adenine dinucleotide (NAD+) levels were determined. Autophagosomes and apoptosomes in the myocardium were detected by transmission electron microscopy. The levels of Bcl-2, cleaved caspase-3, Beclin-1, microtubule-associated protein light chain 3 (LC3)-I/II, Na+/H+ exchanger 1 (NHE1) and phosphorylated NHE1 protein were measured by western blot analysis. NHE1 mRNA levels were measured by reverse transcription-quantitative polymerase chain reaction. Compared with the I/R group, 15 min of exposure to 2.5% sevoflurane during early reperfusion significantly decreased the myocardial infarct size, the autophagic vacuole numbers, the NHE1 mRNA and protein expression of cleaved caspase-3, Beclin-1 and LC3-I/II. Post-conditioning with 2.5% sevoflurane also increased the NO and NOS levels and Bcl-2 protein expression (P<0.05 or P<0.01). Notably, the cardioprotective effects of sevoflurane were partly abolished by the NOS inhibitor, L-NAME. The findings of the present study suggest that sevoflurane post-conditioning protects the myocardium against I/R injury and reduces the myocardial infarct size. The underlying protective mechanisms are associated with the inhibition of mitochondrial permeability transition pore opening, and with the attenuation of cardiomyoctye apoptosis and excessive autophagy. These effects are mediated through an increase in NOS and a decrease in phopshorylated NHE1 levels.
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Affiliation(s)
- Jianfang Cao
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Hong Xie
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Ying Sun
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Jiang Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Ming Ying
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Shigang Qiao
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Qin Shao
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Haorong Wu
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - Chen Wang
- Department of Anesthesiology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
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16
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Shi X, O'Neill MM, MacDonnell S, Brookes PS, Yan C, Berk BC. The RSK Inhibitor BIX02565 Limits Cardiac Ischemia/Reperfusion Injury. J Cardiovasc Pharmacol Ther 2015; 21:177-86. [PMID: 26130615 DOI: 10.1177/1074248415591700] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/06/2015] [Indexed: 02/01/2023]
Abstract
AIMS During ischemia/reperfusion (I/R), ribosomal S6 kinase (RSK) activates Na(+)/H(+) exchanger 1 (NHE1) by phosphorylating NHE1 at serine 703 (pS703-NHE1), which promotes cardiomyocyte death and injury. Pharmacologic inhibition of NHE1 effectively protects animal hearts from I/R. However, clinical trials using NHE1 inhibitors failed to show benefit in patients with acute myocardial infarction (MI). One possible explanation is those inhibitors block both agonist-stimulated activity (increasing I/R injury) and basal NHE1 activity (necessary for cell survival). We previously showed that dominant-negative RSK (DN-RSK) selectively blocked agonist-stimulated NHE1 activity. Therefore, we hypothesized that a novel RSK inhibitor (BIX02565) would blunt agonist-stimulated NHE1 and protect hearts from I/R. METHODS AND RESULTS Serum/angiotensin II-stimulated pS703-NHE1 was significantly decreased by BIX02565 in cultured cells. Intracellular pH recovery assay showed that BIX02565 selectively inhibited serum-stimulated NHE1 activity. Ischemia/reperfusion decreased left ventricular-developed pressure (LVDP; inhibited) to 8.7% of the basal level in non-transgenic littermate control (NLC) mouse hearts, which was significantly improved (44.6%) by BIX02565. Similar protection was observed in vehicle-treated, cardiac-specific DN-RSK-Tg mice (43%). No additional protective effect was seen in BIX02565-treated DN-RSK-Tg hearts. BIX02565 also improved LVDP in cardiac-specific wild-type (WT)-RSK-Tg mouse hearts (7.4%-40.9%, P < .01). Finally, Western Blotting results confirmed DN-RSK and BIX02565 significantly decreased I/R-induced pS703-NHE1. CONCLUSION The RSK plays a crucial role in I/R-induced activation of NHE1 and cardiac injury. The RSK inhibition may provide an alternative target for patients with MI.
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Affiliation(s)
- Xi Shi
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Margaret M O'Neill
- Department of CardioMetabolic Diseases Research, Boehringer-Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, USA
| | - Scott MacDonnell
- Department of CardioMetabolic Diseases Research, Boehringer-Ingelheim Pharmaceuticals, Inc, Ridgefield, CT, USA
| | - Paul S Brookes
- Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Chen Yan
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Bradford C Berk
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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17
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Seidlmayer LK, Juettner VV, Kettlewell S, Pavlov EV, Blatter LA, Dedkova EN. Distinct mPTP activation mechanisms in ischaemia-reperfusion: contributions of Ca2+, ROS, pH, and inorganic polyphosphate. Cardiovasc Res 2015; 106:237-48. [PMID: 25742913 DOI: 10.1093/cvr/cvv097] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 01/30/2015] [Indexed: 12/16/2022] Open
Abstract
AIMS The mitochondrial permeability transition pore (mPTP) plays a central role for tissue damage and cell death during ischaemia-reperfusion (I/R). We investigated the contribution of mitochondrial inorganic polyphosphate (polyP), a potent activator of Ca(2+)-induced mPTP opening, towards mPTP activation and cardiac cell death in I/R. METHODS AND RESULTS A significant increase in mitochondrial free calcium concentration ([Ca(2+)]m), reactive oxygen species (ROS) generation, mitochondrial membrane potential depolarization (ΔΨm), and mPTP activity, but no cell death, was observed after 20 min of ischaemia. The [Ca(2+)]m increase during ischaemia was partially prevented by the mitochondrial Ca(2+) uniporter (MCU) inhibitor Ru360 and completely abolished by the combination of Ru360 and the ryanodine receptor type 1 blocker dantrolene, suggesting two complimentary Ca(2+) uptake mechanisms. In the absence of Ru360 and dantrolene, mPTP closing by polyP depletion or CSA decreased mitochondrial Ca(2+) uptake, suggesting that during ischaemia Ca(2+) can enter mitochondria through mPTP. During reperfusion, a burst of endogenous polyP production coincided with a decrease in [Ca(2+)]m, a decline in superoxide generation, and an acceleration of hydrogen peroxide (H2O2) production. An increase in H2O2 correlated with restoration of mitochondrial pHm and an increase in cell death. mPTP opening and cell death on reperfusion were prevented by antioxidants Trolox and MnTBAP [Mn (III) tetrakis (4-benzoic acid) porphyrin chloride]. Enzymatic polyP depletion did not affect mPTP opening during reperfusion, but increased ROS generation and cell death, suggesting that polyP plays a protective role in cellular stress response. CONCLUSIONS Transient Ca(2+)/polyP-mediated mPTP opening during ischaemia may serve to protect cells against cytosolic Ca(2+) overload, whereas ROS/pH-mediated sustained mPTP opening on reperfusion induces cell death.
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Affiliation(s)
- Lea K Seidlmayer
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1750 W. Harrison St, Chicago, IL 60612, USA
| | - Vanessa V Juettner
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1750 W. Harrison St, Chicago, IL 60612, USA
| | - Sarah Kettlewell
- Institute of Cardiovascular and Medical Sciences, College of Veterinary Medical and Life Sciences, University of Glasgow, Glasgow, UK
| | - Evgeny V Pavlov
- Dalhousie University, Halifax, NS, Canada New York University, NY, USA
| | - Lothar A Blatter
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1750 W. Harrison St, Chicago, IL 60612, USA
| | - Elena N Dedkova
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1750 W. Harrison St, Chicago, IL 60612, USA
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18
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Sheng JJ, Chen Y, Chang H, Wang YY, Jiao B, Yu ZB. Multisite phosphorylation of Bcl-2 via protein kinase Cδfacilitates apoptosis of hypertrophic cardiomyocytes. Clin Exp Pharmacol Physiol 2014; 41:891-901. [DOI: 10.1111/1440-1681.12295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Juan-Juan Sheng
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Yan Chen
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Hui Chang
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Yun-Ying Wang
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Bo Jiao
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
| | - Zhi-Bin Yu
- Department of Aerospace Physiology; Fourth Military Medical University; Xi'an China
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19
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Odunewu-Aderibigbe A, Fliegel L. The Na+/H+exchanger and pH regulation in the heart. IUBMB Life 2014; 66:679-85. [DOI: 10.1002/iub.1323] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 10/15/2014] [Indexed: 11/11/2022]
Affiliation(s)
| | - Larry Fliegel
- Department of Biochemistry; University of Alberta; Edmonton AB Canada
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20
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KCNE2 modulates cardiac L-type Ca2+ channel. J Mol Cell Cardiol 2014; 72:208-18. [DOI: 10.1016/j.yjmcc.2014.03.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 03/05/2014] [Accepted: 03/18/2014] [Indexed: 11/19/2022]
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21
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Dollé JP, Morrison B, Schloss RS, Yarmush ML. Brain-on-a-chip microsystem for investigating traumatic brain injury: Axon diameter and mitochondrial membrane changes play a significant role in axonal response to strain injuries. TECHNOLOGY 2014; 2:106. [PMID: 25101309 PMCID: PMC4120884 DOI: 10.1142/s2339547814500095] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Diffuse axonal injury (DAI) is a devastating consequence of traumatic brain injury, resulting in significant axon and neuronal degeneration. Currently, therapeutic options are limited. Using our brain-on-a-chip device, we evaluated axonal responses to DAI. We observed that axonal diameter plays a significant role in response to strain injury, which correlated to delayed elasticity and inversely correlated to axonal beading and axonal degeneration. When changes in mitochondrial membrane potential (MMP) were monitored an applied strain injury threshold was noted, below which delayed hyperpolarization was observed and above which immediate depolarization occurred. When the NHE-1 inhibitor EIPA was administered before injury, inhibition in both hyperpolarization and depolarization occurred along with axonal degeneration. Therefore, axonal diameter plays a significant role in strain injury and our brain-on-a-chip technology can be used both to understand the biochemical consequences of DAI and screen for potential therapeutic agents.
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22
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Fuster DG, Alexander RT. Traditional and emerging roles for the SLC9 Na+/H+ exchangers. Pflugers Arch 2013; 466:61-76. [PMID: 24337822 DOI: 10.1007/s00424-013-1408-8] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/14/2013] [Accepted: 11/20/2013] [Indexed: 10/25/2022]
Abstract
The SLC9 gene family encodes Na(+)/H(+) exchangers (NHEs). These transmembrane proteins transport ions across lipid bilayers in a diverse array of species from prokaryotes to eukaryotes, including plants, fungi, and animals. They utilize the electrochemical gradient of one ion to transport another ion against its electrochemical gradient. Currently, 13 evolutionarily conserved NHE isoforms are known in mammals [22, 46, 128]. The SLC9 gene family (solute carrier classification of transporters: www.bioparadigms.org) is divided into three subgroups [46]. The SLC9A subgroup encompasses plasmalemmal isoforms NHE1-5 (SLC9A1-5) and the predominantly intracellular isoforms NHE6-9 (SLC9A6-9). The SLC9B subgroup consists of two recently cloned isoforms, NHA1 and NHA2 (SLC9B1 and SLC9B2, respectively). The SLC9C subgroup consist of a sperm specific plasmalemmal NHE (SLC9C1) and a putative NHE, SLC9C2, for which there is currently no functional data [46]. NHEs participate in the regulation of cytosolic and organellar pH as well as cell volume. In the intestine and kidney, NHEs are critical for transepithelial movement of Na(+) and HCO3(-) and thus for whole body volume and acid-base homeostasis [46]. Mutations in the NHE6 or NHE9 genes cause neurological disease in humans and are currently the only NHEs directly linked to human disease. However, it is becoming increasingly apparent that members of this gene family contribute to the pathophysiology of multiple human diseases.
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Affiliation(s)
- Daniel G Fuster
- Division of Nephrology, Hypertension and Clinical Pharmacology and Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland,
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23
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Prasad V, Lorenz JN, Miller ML, Vairamani K, Nieman ML, Wang Y, Shull GE. Loss of NHE1 activity leads to reduced oxidative stress in heart and mitigates high-fat diet-induced myocardial stress. J Mol Cell Cardiol 2013; 65:33-42. [PMID: 24080184 PMCID: PMC3883452 DOI: 10.1016/j.yjmcc.2013.09.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 09/16/2013] [Accepted: 09/21/2013] [Indexed: 12/23/2022]
Abstract
Acute inhibition of the NHE1 Na(+)/H(+) exchanger protects against ischemia-reperfusion injury and chronic inhibition attenuates development of cardiac hypertrophy and failure. To determine the cardiac effects of chronic inhibition of NHE1 under non-pathological conditions we used NHE1-null mice as a model of long-term NHE1 inhibition. Cardiovascular performance was relatively normal in Nhe1(-/-) mice although cardiac contractility and relaxation were slightly improved in mutant mice of the FVB/N background. GSH levels and GSH:GSSG ratios were elevated in Nhe1(-/-) hearts indicating an enhanced redox potential. Consistent with a reduced need for antioxidant protection, expression of heat shock proteins Hsp60 and Hsp25 was lower in Nhe1(-/-) hearts. Similarly, expression of mitochondrial superoxide dismutase 2 was reduced, with no increase in expression of other ROS scavenging enzymes. GLUT1 levels were increased in Nhe1(-/-) hearts, the number of lipid droplets in myocytes was reduced, and PDK4 expression was refractory to high-fat diet-induced upregulation observed in wild-type hearts. High-fat diet-induced stress was attenuated in Nhe1(-/-) hearts, as indicated by smaller increases in phosphorylation of Hsp25 and α-B crystallin, and there was better preservation of insulin sensitivity, as evidenced by PKB/Akt phosphorylation. Plasma glucose and insulin levels were lower and high-fat diet-induced hepatic lipid accumulation was reduced in Nhe1(-/-) mice, demonstrating extracardiac effects of NHE1 ablation. These data indicate that long-term ablation of NHE1 activity increases the redox potential, mitigates high-fat diet-induced myocardial stress and fatty liver disease, leads to better preservation of insulin sensitivity, and may alter both cardiac and systemic metabolic substrate handling in mice.
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Affiliation(s)
- Vikram Prasad
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - John N. Lorenz
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Marian L. Miller
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Kanimozhi Vairamani
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Michelle L. Nieman
- Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Yigang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
| | - Gary E. Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524
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Díaz RG, Pérez NG, Morgan PE, Villa-Abrille MC, Caldiz CI, Nolly MB, Portiansky EL, Ennis IL, Cingolani HE. Myocardial mineralocorticoid receptor activation by stretching and its functional consequences. Hypertension 2013; 63:112-8. [PMID: 24126173 DOI: 10.1161/hypertensionaha.113.01726] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Myocardial stretch triggers an angiotensin II-dependent autocrine/paracrine loop of intracellular signals, leading to reactive oxygen species-mediated activation of redox-sensitive kinases. Based on pharmacological strategies, we previously proposed that mineralocorticoid receptor (MR) is necessary for this stretch-triggered mechanism. Now, we aimed to test the role of MR after stretch by using a molecular approach to avoid secondary effects of pharmacological MR blockers. Small hairpin interference RNA capable of specifically knocking down the MR was incorporated into a lentiviral vector (l-shMR) and injected into the left ventricular wall of Wistar rats. The same vector but expressing a nonsilencing sequence (scramble) was used as control. Lentivirus propagation through the left ventricle was evidenced by confocal microscopy. Myocardial MR expression, stretch-triggered activation of redox-sensitive kinases (ERK1/2-p90(RSK)), the consequent Na(+)/H(+) exchanger-mediated changes in pHi (HEPES-buffer), and its mechanical counterpart, the slow force response, were evaluated. Furthermore, reactive oxygen species production in response to a low concentration of angiotensin II (1.0 nmol/L) or an equipotent concentration of epidermal growth factor (0.1 μg/mL) was compared in myocardial tissue slices from both groups. Compared with scramble, animals transduced with l-shMR showed (1) reduced cardiac MR expression, (2) cancellation of angiotensin II-induced reactive oxygen species production but preservation of epidermal growth factor-induced reactive oxygen species production, (3) cancellation of stretch-triggered increase in ERK1/2-p90(RSK) phosphorylation, (4) lack of stretch-induced Na(+)/H(+) exchanger activation, and (5) abolishment of the slow force response. Our results provide strong evidence that MR activation occurs after myocardial stretch and is a key factor to promote redox-sensitive kinase activation and their downstream consequences.
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Affiliation(s)
- Romina G Díaz
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, UNLP, 60 y 120, 1900 La Plata, Argentina.
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25
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Orlowski A, Vargas LA, Aiello EA, Álvarez BV. Elevated carbon dioxide upregulates NBCn1 Na+/HCO3(-) cotransporter in human embryonic kidney cells. Am J Physiol Renal Physiol 2013; 305:F1765-74. [PMID: 24005470 DOI: 10.1152/ajprenal.00096.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The NBCn1 Na(+)/HCO3(-) cotransporter catalyzes the electroneutral movement of 1 Na(+):1 HCO3(-) into kidney cells. We characterized the intracellular pH (pHi) regulation in human embryonic kidney cells (HEK) subjected to NH4Cl prepulse acid loading, and we examined the NBCn1 expression and function in HEK cells subjected to 24-h elevated Pco2 (10-15%). After acid loading, in the presence of HCO3(-), ∼50% of the pHi recovery phase was blocked by the Na(+)/H(+) exchanger inhibitors EIPA (10-50 μM) and amiloride (1 mM) and was fully cancelled by 30 μM EIPA under nominally HCO3(-)-free conditions. In addition, in the presence of HCO3(-), pHi recovery after acid loading was completely blocked when Na(+) was omitted in the buffer. pHi recovery after acidification in HEK cells was repeated in the presence of the NBC inhibitor S0859, and the pHi recovery was inhibited by S0859 in a dose-dependent manner (Ki = 30 μM, full inhibition at 60 μM), which confirmed NBC Na(+)/HCO3(-) cotransporter activation. NBCn1 expression increased threefold after 24-h exposure of cultured HEK cells to 10% CO2 and sevenfold after exposure to 15% CO2, examined by immunoblots. Finally, exposure of HEK cells to high CO2 significantly increased the HCO3(-)-dependent recovery of pHi after acid loading. We conclude that HEK cells expressed the NBCn1 Na(+)/HCO3(-) cotransporter as the only HCO3(-)-dependent mechanism responsible for cellular alkaline loading. NBCn1, which expresses in different kidney cell types, was upregulated by 24-h high-Pco2 exposure of HEK cells, and this upregulation was accompanied by increased NBCn1-mediated HCO3(-) transport.
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Affiliation(s)
- Alejandro Orlowski
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, UNLP, Calle 60 y 120, 1900, La Plata, Argentina.
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Javadov S, Kuznetsov AV. Mitochondria: the cell powerhouse and nexus of stress. Front Physiol 2013; 4:207. [PMID: 23966947 PMCID: PMC3735979 DOI: 10.3389/fphys.2013.00207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 07/21/2013] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sabzali Javadov
- Department of Physiology, School of Medicine, University of Puerto Rico San Juan, Puerto Rico
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Alvarez BV, Villa-Abrille MC. Mitochondrial NHE1: a newly identified target to prevent heart disease. Front Physiol 2013; 4:152. [PMID: 23825461 PMCID: PMC3695379 DOI: 10.3389/fphys.2013.00152] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 06/09/2013] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial damage has been associated with early steps of cardiac dysfunction in heart subjected to ischemic stress, oxidative stress and hypertrophy. A common feature for the mitochondrial deterioration is the loss of the mitochondrial membrane potential (ΔΨ m) with the concomitant irreversible opening of the mitochondrial permeability transition pore (MPTP) which follows the mitochondrial Ca2+ overload, and the subsequent mitochondrial swelling. We have recently characterized the expression of the Na+/H+ exchanger 1 (mNHE1) in mitochondrial membranes. This surprising observation provided a unique target for the prevention of the Ca2+-induced MPTP opening, based on the inhibition of the NHE1 m. In this line, inhibition of NHE1 m activity and/or reduction of NHE1 m expression decreased the Ca2+-induced mitochondrial swelling and the release of reactive oxygen species (ROS) in isolated cardiac mitochondria and preserved the ΔΨ m in isolated cardiomyocytes. Mitochondrial NHE1 thus represents a novel target to prevent cardiac disease, opening new avenues for future research.
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Affiliation(s)
- Bernardo V Alvarez
- Centro de Investigaciones Cardiovasculares, Consejo Nacional de Investigaciones Científicas y Técnicas Facultad de Ciencias Médicas, Universidad Nacional de La Plata La Plata, Argentina
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DeSantiago J, Bare DJ, Banach K. Ischemia/Reperfusion injury protection by mesenchymal stem cell derived antioxidant capacity. Stem Cells Dev 2013; 22:2497-507. [PMID: 23614555 DOI: 10.1089/scd.2013.0136] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mesenchymal stem cell (MSC) transplantation after ischemia/reperfusion (I/R) injury reduces infarct size and improves cardiac function. We used mouse ventricular myocytes (VMs) in an in vitro model of I/R to determine the mechanism by which MSCs prevent reperfusion injury by paracrine signaling. Exposure of mouse VMs to an ischemic challenge depolarized their mitochondrial membrane potential (Ψmito), increased their diastolic Ca(2+), and significantly attenuated cell shortening. Reperfusion of VMs with Ctrl tyrode or MSC-conditioned tyrode (ConT) resulted in a transient increase of the Ca(2+) transient amplitudes in all cells. ConT-reperfused cells exhibited a decreased number early after depolarization (EADs) (ConT: 6.3% vs. Ctrl: 28.4%) and prolonged survival (ConT: 58% vs. Ctrl: 33%). Ψmito rapidly recovered in Ctrl as well as ConT-treated VMs on reperfusion; however, in Ctrl solution, an exaggerated hyperpolarization of Ψmito was determined that preceded the collapse of Ψmito. The ability of ConT to attenuate the hyperpolarization of Ψmito was suppressed on inhibition of the PI3K/Akt signaling pathway or IK,ATP. However, protection of Ψmito was best mimicked by the reactive oxygen species (ROS) scavenger mitoTEMPO. Analysis of ConT revealed a significant antioxidant capacity that was linked to the presence of extracellular superoxide dismutase (SOD3) in ConT. In conclusion, MSC ConT protects VMs from simulated I/R injury by its SOD3-mediated antioxidant capacity and by delaying the recovery of Ψmito through Akt-mediated opening of IK,ATP. These changes attenuate reperfusion-induced ROS production and prevent the opening of the permeability transition pore and arrhythmic Ca(2+) release.
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Affiliation(s)
- Jaime DeSantiago
- Section of Cardiology, Department of Medicine, Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Illinois 60612-7323, USA
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29
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Abstract
Myocardial stretch elicits a rapid increase in developed force, which is mainly caused by an increase in myofilament calcium sensitivity (Frank-Starling mechanism). Over the ensuing 10-15 min, a second gradual increase in force takes place. This slow force response to stretch is known to be the result of an increase in the calcium transient amplitude and constitutes the in vitro equivalent of the Anrep effect described 100 years ago in the intact heart. In the present review, we will update and discuss what is known about the Anrep effect as the mechanical counterpart of autocrine/paracrine mechanisms involved in its genesis. The chain of events triggered by myocardial stretch comprises 1) release of angiotensin II, 2) release of endothelin, 3) activation of the mineralocorticoid receptor, 4) transactivation of the epidermal growth factor receptor, 5) increased formation of mitochondria reactive oxygen species, 6) activation of redox-sensitive kinases upstream myocardial Na(+)/H(+) exchanger (NHE1), 7) NHE1 activation, 8) increase in intracellular Na(+) concentration, and 9) increase in Ca(2+) transient amplitude through the Na(+)/Ca(2+) exchanger. We will present the experimental evidence supporting each of the signaling steps leading to the Anrep effect and its blunting by silencing NHE1 expression with a specific small hairpin interference RNA injected into the ventricular wall.
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Affiliation(s)
- Horacio E Cingolani
- Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata, La Plata, Argentina.
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Kurian GA, Berenshtein E, Kakhlon O, Chevion M. Energy status determines the distinct biochemical and physiological behavior of interfibrillar and sub-sarcolemmal mitochondria. Biochem Biophys Res Commun 2012; 428:376-82. [DOI: 10.1016/j.bbrc.2012.10.062] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 10/16/2012] [Indexed: 12/30/2022]
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Orlowski A, De Giusti VC, Morgan PE, Aiello EA, Álvarez BV. Binding of carbonic anhydrase IX to extracellular loop 4 of the NBCe1 Na+/HCO3− cotransporter enhances NBCe1-mediated HCO3− influx in the rat heart. Am J Physiol Cell Physiol 2012; 303:C69-80. [DOI: 10.1152/ajpcell.00431.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Na+/HCO3− cotransporter (NBC)e1 catalyze the electrogenic movement of 1 Na+:2 HCO3− into cardiomyocytes cytosol. NBC proteins associate with carbonic anhydrases (CA), CAII, and CAIV, forming a HCO3− transport metabolon. Herein, we examined the physical/functional interaction of NBCe1 and transmembrane CAIX in cardiac muscle. NBCe1 and CAIX physical association was examined by coimmunoprecipitation, using rat ventricular lysates. NBCe1 coimmunoprecipitated with anti-CAIX antibody, indicating NBCe1 and CAIX interaction in the myocardium. Glutathione- S-transferase (GST) pull-down assays with predicted extracellular loops (EC) of NBCe1 revealed that NBCe1-EC4 mediated interaction with CAIX. Functional NBCe1/CAIX interaction was examined using fluorescence measurements of BCECF in rat cardiomyocytes to monitor cytosolic pH. NBCe1 transport activity was evaluated after membrane depolarization with high extracellular K+ in the presence or absence of the CA inhibitors, benzolamide (BZ; 100 μM) or 6-ethoxyzolamide (ETZ; 100 μM) (* P < 0.05). This depolarization protocol produced an intracellular pH (pHi) increase of 0.17 ± 0.01 ( n = 11), which was inhibited by BZ (0.11 ± 0.02; n = 7) or ETZ (0.06 ± 0.01; n = 6). NBCe1 activity was also measured by changes of pHi in NBCe1-transfected human embryonic kidney 293 cells subjected to acid loads. Cotransfection of CAIX with NBCe1 increased the rate of pHi recovery (in mM/min) by about fourfold (12.1 ± 0.8; n = 9) compared with cells expressing NBCe1 alone (3.1 ± 0.5; n = 7), which was inhibited by BZ (7.5 ± 0.3; n = 9). We demonstrated that CAIX forms a complex with EC4 of NBCe1, which activates NBCe1-mediated HCO3− influx in the myocardium. CAIX and NBCe1 have been linked to tumorigenesis and cardiac cell growth, respectively. Thus inhibition of CA activity might be useful to prevent activation of NBCe1 under these pathological conditions.
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Affiliation(s)
- Alejandro Orlowski
- Centro de Investigaciones Cardiovasculares, CONICET-Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Verónica C. De Giusti
- Centro de Investigaciones Cardiovasculares, CONICET-Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Patricio E. Morgan
- Centro de Investigaciones Cardiovasculares, CONICET-Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Ernesto A. Aiello
- Centro de Investigaciones Cardiovasculares, CONICET-Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Bernardo V. Álvarez
- Centro de Investigaciones Cardiovasculares, CONICET-Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
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Vargas LA, Alvarez BV. Carbonic anhydrase XIV in the normal and hypertrophic myocardium. J Mol Cell Cardiol 2011; 52:741-52. [PMID: 22227327 DOI: 10.1016/j.yjmcc.2011.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 11/21/2011] [Accepted: 12/14/2011] [Indexed: 01/20/2023]
Abstract
Two AE3 transcripts, full-length (AE3fl) and cardiac (AE3c) are expressed in the heart. AE3 catalyzes electroneutral Cl(-)/HCO(3)(-) exchange across cardiomyocyte sarcolemma. AE proteins associate with carbonic anhydrases (CA), including CAII and CAIV, forming a HCO(3)(-) transport metabolon (BTM), increasing HCO(3)(-) fluxes and regulating cardiomyocytes pH. CAXIV, which is also expressed in the heart's sarcolemma, is a transmembrane enzyme with an extracellular catalytic domain. Herein, AE3/CAXIV physical association was examined by coimmunoprecipitation using rodent heart lysates. CAXIV immunoprecipitated with anti-AE3 antibody and both AE3fl and AE3c were reciprocally immunoprecipitated using anti-CAXIV antibody, indicating AE3fl-AE3c/CAXIV interaction in the myocardium. Coimmunoprecipitation experiments on heart lysates from a mouse with targeted disruption of the ae3 gene, failed to pull down AE3 with the CAXIV antibody. Confocal images demonstrated colocalization of CAXIV and AE3 in mouse ventricular myocytes. Functional association of AE3fl and CAXIV was examined in isolated hypertrophic rat cardiomyocytes, using fluorescence measurements of BCECF to monitor cytosolic pH. Hypertrophic cardiomyocytes of spontaneously hypertensive rats (SHR) presented elevated myocardial AE-mediated Cl(-)/HCO(3)(-) exchange activity (J(HCO3-) mM.min(-1)) compared to normal (Wistar) rats (7.5±1.3, n=4 versus 2.9±0.1, n=6, respectively). AE3fl, AE3c, CAII, CAIV, and CAIX protein expressions were similar in SHR and Wistar rat hearts. However, immunoblots revealed a twofold increase of CAXIV protein expression in the SHR myocardium compared to normal hearts (n=11). Furthermore, the CA-inhibitor, benzolamide, neutralized the stimulatory effect of extracellular CA on AE3 transport activity (3.7±1.5, n=3), normalizing AE3-dependent HCO(3)(-) fluxes in SHR. CAXIV/AE3 interaction constitutes an extracellular component of a BTM which potentiates AE3-mediated HCO(3)(-) transport in the heart. Increased CAXIV expression and consequent AE3/CAXIV complex formation would render AE3 hyperactive in the SHR heart.
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Affiliation(s)
- Lorena A Vargas
- Centro de Investigaciones Cardiovasculares, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina
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Ong SB, Gustafsson AB. New roles for mitochondria in cell death in the reperfused myocardium. Cardiovasc Res 2011; 94:190-6. [PMID: 22108916 DOI: 10.1093/cvr/cvr312] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mitochondria play an important role in regulating the life and death of cells. They provide the cell with energy via oxidative phosphorylation but can quickly turn into death-promoting organelles in response to stress by disrupting adenosine triphosphate synthesis, releasing pro-death proteins, and producing reactive oxygen species. Due to their high-energy requirement, cardiac myocytes are abundant in mitochondria and as a result, particularly vulnerable to mitochondrial defects. Myocardial ischaemia and reperfusion are associated with mitochondrial dysfunction and cell death. Therefore, future therapies will focus on preserving mitochondrial integrity and function in hopes of minimizing the impact of ischaemia/reperfusion (I/R) injury. It is well established that myocardial I/R activates both necrosis and apoptosis, and that blocking either process reduces the levels of injury. However, recent studies have demonstrated that alterations in mitochondrial dynamics or clearance of mitochondria via autophagy also can contribute to cell death in the myocardium. In this review, we will discuss these new developments and their impact on the role of cardiac mitochondria in cell death following reperfusion in the heart.
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Affiliation(s)
- Sang-Bing Ong
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA 92093-0758, USA
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