1
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Steinhorn B, Eroglu E, Michel T. Chemogenetic Approaches to Probe Redox Pathways: Implications for Cardiovascular Pharmacology and Toxicology. Annu Rev Pharmacol Toxicol 2022; 62:551-571. [PMID: 34530645 PMCID: PMC10507364 DOI: 10.1146/annurev-pharmtox-012221-082339] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chemogenetics refers to experimental systems that dynamically regulate the activity of a recombinant protein by providing or withholding the protein's specific biochemical stimulus. Chemogenetic tools permit precise dynamic control of specific signaling molecules to delineate the roles of those molecules in physiology and disease. Yeast d-amino acid oxidase (DAAO) enables chemogenetic manipulation of intracellular redox balance by generating hydrogen peroxide only in the presence of d-amino acids. Advances in biosensors have allowed the precise quantitation of these signaling molecules. The combination of chemogenetic approaches with biosensor methodologies has opened up new lines of investigation, allowing the analysis of intracellular redox pathways that modulate physiological and pathological cell responses. We anticipate that newly developed transgenic chemogenetic models will permit dynamic modulation of cellularredox balance in diverse cells and tissues and will facilitate the identification and validation of novel therapeutic targets involved in both physiological redox pathways and pathological oxidative stress.
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Affiliation(s)
- Benjamin Steinhorn
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| | - Emrah Eroglu
- Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul 34956, Turkey
- Department of Molecular Biology and Biochemistry, Medical University of Graz, 8036 Graz, Austria
| | - Thomas Michel
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
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2
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Tran N, Garcia T, Aniqa M, Ali S, Ally A, Nauli SM. Endothelial Nitric Oxide Synthase (eNOS) and the Cardiovascular System: in Physiology and in Disease States. AMERICAN JOURNAL OF BIOMEDICAL SCIENCE & RESEARCH 2022; 15:153-177. [PMID: 35072089 PMCID: PMC8774925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Endothelial nitric oxide synthase (eNOS) plays a critical role in regulating and maintaining a healthy cardiovascular system. The importance of eNOS can be emphasized from the genetic polymorphisms of the eNOS gene, uncoupling of eNOS dimerization, and its numerous signaling regulations. The activity of eNOS on the cardiac myocytes, vasculature, and the central nervous system are discussed. The effects of eNOS on the sympathetic autonomic nervous system (SANS) and the parasympathetic autonomic nervous system (PANS), both of which profoundly influence the cardiovascular system, will be elaborated. The relationship between the eNOS protein with cardiovascular autonomic reflexes such as the baroreflex and the Exercise Pressor Reflex will be discussed. For example, the effects of endogenous nitric oxide (NO) are shown to be mediated by the eNOS protein and that eNOS-derived endothelial NO is most effective in regulating blood pressure oscillations via modulating the baroreflex mechanisms. The protective action of eNOS on the CVS is emphasized here because dysfunction of the eNOS enzyme is intricately correlated with the pathogenesis of several cardiovascular diseases such as hypertension, arteriosclerosis, myocardial infarction, and stroke. Overall, our current understanding of the eNOS protein with a focus on its role in the modulation, regulation, and control of the cardiovascular system in a normal physiological state and in cardiovascular diseases are discussed.
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Affiliation(s)
- N Tran
- Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA
| | - T Garcia
- Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA
| | - M Aniqa
- Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA
| | - S Ali
- Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA
| | - A Ally
- Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA,Corresponding author: Surya M Nauli, Chapman University and University of California, Irvine, CA, USA
| | - SM Nauli
- Chapman University and University of California, Irvine, CA, USA,Corresponding author: Surya M Nauli, Chapman University and University of California, Irvine, CA, USA
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3
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Mosqueira M, Konietzny R, Andresen C, Wang C, H A Fink R. Cardiomyocyte depolarization triggers NOS-dependent NO transient after calcium release, reducing the subsequent calcium transient. Basic Res Cardiol 2021; 116:18. [PMID: 33728868 PMCID: PMC7966140 DOI: 10.1007/s00395-021-00860-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 03/09/2021] [Indexed: 12/18/2022]
Abstract
Cardiac excitation-contraction coupling and metabolic and signaling activities are centrally modulated by nitric oxide (NO), which is produced by one of three NO synthases (NOSs). Despite the significant role of NO in cardiac Ca2+ homeostasis regulation under different pathophysiological conditions, such as Duchenne muscular dystrophy (DMD), no precise method describes the production, source or effect of NO through two NO signaling pathways: soluble guanylate cyclase-protein kinase G (NO-sGC-PKG) and S-nitrosylation (SNO). Using a novel strategy involving isolated murine cardiomyocytes loaded with a copper-based dye highly specific for NO, we observed a single transient NO production signal after each electrical stimulation event. The NO transient signal started 67.5 ms after the beginning of Rhod-2 Ca2+ transient signal and lasted for approximately 430 ms. Specific NOS isoform blockers or NO scavengers significantly inhibited the NO transient, suggesting that wild-type (WT) cardiomyocytes produce nNOS-dependent NO transients. Conversely, NO transient in mdx cardiomyocyte, a mouse model of DMD, was dependent on inducible NOS (iNOS) and endothelial (eNOS). In a consecutive stimulation protocol, the nNOS-dependent NO transient in WT cardiomyocytes significantly reduced the next Ca2+ transient via NO-sGC-PKG. In mdx cardiomyocytes, this inhibitory effect was iNOS- and eNOS-dependent and occurred through the SNO pathway. Basal NO production was nNOS- and iNOS-dependent in WT cardiomyocytes and eNOS- and iNOS-dependent in mdx cardiomyocytes. These results showed cardiomyocyte produces NO isoform-dependent transients upon membrane depolarization at the millisecond time scale activating a specific signaling pathway to negatively modulate the subsequent Ca2+ transient.
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Affiliation(s)
- Matias Mosqueira
- Cardio-Ventilatory Muscle Physiology Laboratory, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, Im Neuenheimer Feld 326, R. 305, 69120, Heidelberg, Germany.
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, 69120, Heidelberg, Germany.
| | - Roland Konietzny
- Cardio-Ventilatory Muscle Physiology Laboratory, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, Im Neuenheimer Feld 326, R. 305, 69120, Heidelberg, Germany
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Carolin Andresen
- Cardio-Ventilatory Muscle Physiology Laboratory, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, Im Neuenheimer Feld 326, R. 305, 69120, Heidelberg, Germany
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- Heidelberg Institute for Stem Cell Technology and Experimental Medicine (HI-STEM gGmbH), Heidelberg, Germany
- Division of Stem Cells and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Chao Wang
- Cardio-Ventilatory Muscle Physiology Laboratory, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, Im Neuenheimer Feld 326, R. 305, 69120, Heidelberg, Germany
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- Cardiovascular Department, Wuhan No. 1 Hospital, Hubei, China
| | - Rainer H A Fink
- Medical Biophysics Unit, Institute of Physiology and Pathophysiology, University Hospital Heidelberg, 69120, Heidelberg, Germany
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4
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Vidanapathirana AK, Psaltis PJ, Bursill CA, Abell AD, Nicholls SJ. Cardiovascular bioimaging of nitric oxide: Achievements, challenges, and the future. Med Res Rev 2020; 41:435-463. [PMID: 33075148 DOI: 10.1002/med.21736] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 08/03/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022]
Abstract
Nitric oxide (NO) is a ubiquitous, volatile, cellular signaling molecule that operates across a wide physiological concentration range (pM-µM) in different tissues. It is a highly diffusible messenger and intermediate in various metabolic pathways. NO plays a pivotal role in maintaining optimum cardiovascular function, particularly by regulating vascular tone and blood flow. This review highlights the need for accurate, real-time bioimaging of NO in clinical diagnostic, therapeutic, monitoring, and theranostic applications within the cardiovascular system. We summarize electrochemical, optical, and nanoscale sensors that allow measurement and imaging of NO, both directly and indirectly via surrogate measurements. The physical properties of NO render it difficult to accurately measure in tissues using direct methods. There are also significant limitations associated with the NO metabolites used as surrogates to indirectly estimate NO levels. All these factors added to significant variability in the measurement of NO using available methodology have led to a lack of sensors and imaging techniques of clinical applicability in relevant vascular pathologies such as atherosclerosis and ischemic heart disease. Challenges in applying current methods to biomedical and clinical translational research, including the wide physiological range of NO and limitations due to the characteristics and toxicity of the sensors are discussed, as are potential targets and modifications for future studies. The development of biocompatible nanoscale sensors for use in combination with existing clinical imaging modalities provides a feasible opportunity for bioimaging NO within the cardiovascular system.
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Affiliation(s)
- Achini K Vidanapathirana
- Vascular Research Centre, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia.,Australian Research Council (ARC), Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, Australia.,Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, South Australia, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Peter J Psaltis
- Vascular Research Centre, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia.,Australian Research Council (ARC), Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Christina A Bursill
- Vascular Research Centre, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia.,Australian Research Council (ARC), Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, Australia.,Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Andrew D Abell
- Australian Research Council (ARC), Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, Australia.,Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, South Australia, Australia.,Department of Chemistry, University of Adelaide, Adelaide, South Australia, Australia
| | - Stephen J Nicholls
- Australian Research Council (ARC), Centre of Excellence for Nanoscale BioPhotonics (CNBP), Adelaide, Australia.,Monash Cardiovascular Research Centre, Monash University, Clayton, Victoria, Australia
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5
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Steinhorn B, Sorrentino A, Badole S, Bogdanova Y, Belousov V, Michel T. Chemogenetic generation of hydrogen peroxide in the heart induces severe cardiac dysfunction. Nat Commun 2018; 9:4044. [PMID: 30279532 PMCID: PMC6168530 DOI: 10.1038/s41467-018-06533-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 09/12/2018] [Indexed: 12/16/2022] Open
Abstract
Oxidative stress plays an important role in the pathogenesis of many disease states. In the heart, reactive oxygen species are linked with cardiac ischemia/reperfusion injury, hypertrophy, and heart failure. While this correlation between ROS and cardiac pathology has been observed in multiple models of heart failure, the independent role of hydrogen peroxide (H2O2) in vitro and in vivo is unclear, owing to a lack of tools for precise manipulation of intracellular redox state. Here we apply a chemogenetic system based on a yeast D-amino acid oxidase to show that chronic generation of H2O2 in the heart induces a dilated cardiomyopathy with significant systolic dysfunction. We anticipate that chemogenetic approaches will enable future studies of in vivo H2O2 signaling not only in the heart, but also in the many other organ systems where the relationship between redox events and physiology remains unclear. Excessive production of reactive oxygen species (ROS) is associated with cardiac dysfunction, but the causal role of ROS remains poorly understood. Here the authors use an in vivo chemogenetic approach to develop a heart failure model in which generation of hydrogen peroxide in the heart leads to systolic heart failure without fibrotic remodeling.
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Affiliation(s)
- Benjamin Steinhorn
- Department of Medicine, Division of Cardiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Andrea Sorrentino
- Department of Medicine, Division of Cardiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Sachin Badole
- Department of Medicine, Division of Cardiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Yulia Bogdanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, GSP-7, Ulitsa Miklukho-Maklaya, 16/10, Moscow, Russia, 117997
| | - Vsevolod Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, GSP-7, Ulitsa Miklukho-Maklaya, 16/10, Moscow, Russia, 117997.,Pirogov Russian National Research Medical University, Moscow, Russia, 117997.,Institute for Cardiovascular Physiology, Georg August University Göttingen, D-37075, Göttingen, Germany
| | - Thomas Michel
- Department of Medicine, Division of Cardiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
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6
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Bibli SI, Zhou Z, Zukunft S, Fisslthaler B, Andreadou I, Szabo C, Brouckaert P, Fleming I, Papapetropoulos A. Tyrosine phosphorylation of eNOS regulates myocardial survival after an ischaemic insult: role of PYK2. Cardiovasc Res 2018; 113:926-937. [PMID: 28444132 DOI: 10.1093/cvr/cvx058] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 03/20/2017] [Indexed: 02/06/2023] Open
Abstract
Aims Endothelial nitric oxide (NO) synthase (eNOS) is known to play a cardioprotective protective. However, the molecular mechanisms regulating eNOS activity during ischaemia/reperfusion (I/R) injury are incompletely understood. eNOS is a substrate for several kinases that positively or negatively affect its enzymatic activity. Herein, we sought to correlate eNOS phosphorylation status with cardiomyocyte survival and we investigated the contribution of the proline-rich tyrosine kinase 2 (PYK2)/eNOS axis to the regulation of myocardial infarct size in vivo. Methods and results Exposure of H9c2 cardiomyocytes to H2O2 lead to PYK2 phosphorylation on its activator site (Y402) and eNOS phosphorylation on the inhibitor site Y656 and the activator site S1176. Both H2O2-induced eNOS phosphorylation events were abolished by PYK2 pharmacological inhibition or gene knockdown. Activity assays demonstrated that phosphorylation of the tyrosine inhibitory site exerts a dominant effect over S1176. In cardiomyocytes subjected to oxidative stress or oxygen-glucose deprivation, inhibition of PYK2 limited cell injury; this effect was prevented by inhibition of NO production. In vivo, ischaemia-reperfusion induced an early activation of PYK2, leading to eNOS phosphorylation on Y656, which, in turn, reduced NO output, as judged by the low tissue levels of its downstream effector cGMP. Moreover, pharmacological blockade of PYK2 alleviated eNOS inhibition and prevented cardiac damage following I/R injury in wild-type, but not in eNOS KO mice. Conclusion The current studies demonstrate that PYK2 is a pivotal regulator of eNOS function in myocardial infarction and identify PYK2 as a novel therapeutic target for cardioprotection.
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Affiliation(s)
- Sofia-Iris Bibli
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis, Zografou 15771, Greece.,"George P. Livanos and Marianthi Simou" Laboratories, First Department of Pulmonary and Critical Care Medicine, Evangelismos Hospital, Faculty of Medicine, National and Kapodistrian University of Athens, Ipsilantou 45-47, Athens, 10675 Greece.,Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt am Main, D-60590, Germany
| | - Zongmin Zhou
- "George P. Livanos and Marianthi Simou" Laboratories, First Department of Pulmonary and Critical Care Medicine, Evangelismos Hospital, Faculty of Medicine, National and Kapodistrian University of Athens, Ipsilantou 45-47, Athens, 10675 Greece
| | - Sven Zukunft
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt am Main, D-60590, Germany
| | - Beate Fisslthaler
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt am Main, D-60590, Germany
| | - Ioanna Andreadou
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis, Zografou 15771, Greece
| | - Csaba Szabo
- Department of Anesthesiology, University of Texas Medical Branch, 601 Harborside Drive, Galveston, 77555 TX, USA
| | - Peter Brouckaert
- Department of Biomedical Molecular Biology, Ghent University, Ghent B-9052, Belgium.,Laboratory for Molecular Pathology and Experimental Therapy, Inflammation Research Center, VIB, Ghent B-9052, Belgium
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, Frankfurt am Main, D-60590, Germany
| | - Andreas Papapetropoulos
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis, Zografou 15771, Greece.,"George P. Livanos and Marianthi Simou" Laboratories, First Department of Pulmonary and Critical Care Medicine, Evangelismos Hospital, Faculty of Medicine, National and Kapodistrian University of Athens, Ipsilantou 45-47, Athens, 10675 Greece.,Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Soranou Ephessiou 4, Athens 11527, Greece
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7
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Steinhorn B, Sartoretto JL, Sorrentino A, Romero N, Kalwa H, Abel ED, Michel T. Insulin-dependent metabolic and inotropic responses in the heart are modulated by hydrogen peroxide from NADPH-oxidase isoforms NOX2 and NOX4. Free Radic Biol Med 2017; 113:16-25. [PMID: 28917508 PMCID: PMC5699944 DOI: 10.1016/j.freeradbiomed.2017.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/22/2017] [Accepted: 09/09/2017] [Indexed: 01/08/2023]
Abstract
RATIONALE Hydrogen peroxide (H2O2) is a stable reactive oxygen species (ROS) that has long been implicated in insulin signal transduction in adipocytes. However, H2O2's role in mediating insulin's effects on the heart are unknown. OBJECTIVE We investigated the role of H2O2 in activating insulin-dependent changes in cardiac myocyte metabolic and inotropic pathways. The sources of insulin-dependent H2O2 generation were also studied. METHODS AND RESULTS In addition to the canonical role of insulin in modulating cardiac metabolic pathways, we found that insulin also inhibited beta adrenergic-induced increases in cardiac contractility. Catalase and NADPH oxidase (NOX) inhibitors blunted activation of insulin-responsive kinases Akt and mTOR and attenuated beta adrenergic receptor-mediated responses. These insulin responses were lost in a mouse model of type 2 diabetes, suggesting a role for these H2O2-dependent pathways in the diabetic heart. The H2O2-sensitive fluorescent biosensor HyPer revealed rapid increases in cytosolic and caveolar H2O2 concentrations in response to insulin treatment, which were blocked by NOX inhibitors and attenuated in NOX2 KO and NOX4 KO mice. In NOX2 KO cardiac myocytes, insulin-mediated phosphorylation of Akt and mTOR was blocked, while these responses were unaffected in cardiac myocytes from NOX4 KO mice. In contrast, insulin's effects on contractility were lost in cardiac myocytes from NOX4 KO animals but were retained in NOX2 KO mice. CONCLUSIONS These studies identify a proximal point of bifurcation in cardiac insulin signaling through the simultaneous activation of both NOX2 and NOX4. Each NOX isoform generates H2O2 in cardiac myocytes with distinct time courses, with H2O2 derived from NOX2 augmenting Akt-dependent metabolic effects of insulin, while H2O2 from NOX4 blocks beta adrenergic increases in inotropy. These findings suggest that insulin resistance in the diabetic heart may lead to potentially deleterious potentiation of beta adrenergic responses.
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Affiliation(s)
- Benjamin Steinhorn
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, United States
| | - Juliano L Sartoretto
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, United States
| | - Andrea Sorrentino
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, United States
| | - Natalia Romero
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, United States
| | - Hermann Kalwa
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, United States
| | - E Dale Abel
- University of Iowa School of Medicine, United States
| | - Thomas Michel
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, United States.
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8
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Afolayan AJ, Alexander M, Holme RL, Michalkiewicz T, Rana U, Teng RJ, Zemanovic S, Sahoo D, Pritchard KA, Konduri GG. Domain Mapping of Heat Shock Protein 70 Reveals That Glutamic Acid 446 and Arginine 447 Are Critical for Regulating Superoxide Dismutase 2 Function. J Biol Chem 2016; 292:2369-2378. [PMID: 28028182 DOI: 10.1074/jbc.m116.756122] [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: 08/29/2016] [Revised: 12/19/2016] [Indexed: 12/15/2022] Open
Abstract
Stress-inducible heat shock protein 70 (hsp70) interacts with superoxide dismutase 2 (SOD2) in the cytosol after synthesis to transfer the enzyme to the mitochondria for subsequent activation. However, the structural basis for this interaction remains to be defined. To map the SOD2-binding site in hsp70, mutants of hsp70 were made and tested for their ability to bind SOD2. These studies showed that SOD2 binds in the amino acid 393-537 region of the chaperone. To map the hsp70-binding site in SOD2, we used a series of pulldown assays and showed that hsp70 binds to the amino-terminal domain of SOD2. To better define the binding site, we used a series of decoy peptides derived from the primary amino acid sequence in the SOD2-binding site in hsp70. This study shows that SOD2 specifically binds to hsp70 at 445GERAMT450 Small peptides containing GERAMT inhibited the transfer of SOD2 to the mitochondria and decreased SOD2 activity in vitro and in vivo To determine the amino acid residues in hsp70 that are critical for SOD2 interactions, we substituted each amino acid residue for alanine or more conservative residues, glutamine or asparagine, in the GERAMT-binding site. Substitutions of E446A/Q and R447A/Q inhibited the ability of the GERAMT peptide to bind SOD2 and preserved SOD2 function more than other substitutions. Together, these findings indicate that the GERAMT sequence is critical for hsp70-mediated regulation of SOD2 and that Glu446 and Arg447 cooperate with other amino acid residues in the GERAMT-binding site for proper chaperone-dependent regulation of SOD2 antioxidant function.
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Affiliation(s)
- Adeleye J Afolayan
- From the Department of Pediatrics, Cardiovascular Research Center, .,Children's Research Institute
| | - Maxwell Alexander
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Rebecca L Holme
- Children's Research Institute.,Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Teresa Michalkiewicz
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Ujala Rana
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Ru-Jeng Teng
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Sara Zemanovic
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
| | - Daisy Sahoo
- Children's Research Institute.,Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Kirkwood A Pritchard
- Children's Research Institute.,Department of Surgery, Division of Pediatric Surgery, and
| | - Girija G Konduri
- From the Department of Pediatrics, Cardiovascular Research Center.,Children's Research Institute
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9
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Yang PM, Huang YT, Zhang YQ, Hsieh CW, Wung BS. Carbon monoxide releasing molecule induces endothelial nitric oxide synthase activation through a calcium and phosphatidylinositol 3-kinase/Akt mechanism. Vascul Pharmacol 2016; 87:209-218. [PMID: 27720892 DOI: 10.1016/j.vph.2016.09.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 09/21/2016] [Accepted: 09/30/2016] [Indexed: 11/18/2022]
Abstract
The production of nitric oxide (NO) by endothelial NO synthase (eNOS) plays a major role in maintaining vascular homeostasis. This study elucidated the potential role of carbon monoxide (CO)-releasing molecules (CORMs) in NO production and explored the underlying mechanisms in endothelial cells. We observed that 25μM CORM-2 could increase NO production and stimulate an increase in the intracellular Ca2+ level. Furthermore, ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetra acetic acid caused CORM-2-induced NO production, which was abolished by 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetraacetoxy-methyl ester (BAPTA-AM), indicating that intracellular Ca2+ release plays a major role in eNOS activation. The inhibition of the IP3 receptor diminished the CORM-2-induced intracellular Ca2+ increase and NO production. Furthermore, CORM-2 induced eNOS Ser1179 phosphorylation and eNOS dimerization, but it did not alter eNOS expression. CORM-2 (25μM) also prolonged Akt phosphorylation, lasting for at least 12h. Pretreatment with phosphatidylinositol 3-kinase inhibitors (wortmannin or LY294002) inhibited the increases in NO production and phosphorylation but did not affect eNOS dimerization. CORM-2-induced eNOS Ser1179 phosphorylation was intracellularly calcium-dependent, because pretreatment with an intracellular Ca2+ chelator (BAPTA-AM) inhibited this process. Although CORM-2 increases intracellular reactive oxygen species (ROS), pretreatment with antioxidant enzyme catalase and N-acetyl-cysteine did not abolish the CORM-2-induced eNOS activity or phosphorylation, signifying that ROS is not involved in this activity. Hence, CORM-2 enhances eNOS activation through intracellular calcium release, Akt phosphorylation, and eNOS dimerization.
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Affiliation(s)
- Po-Min Yang
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi 600, Taiwan; Department of Ophthalmology, Chiayi Christian Hospital, Chiayi, Taiwan
| | - Yu-Ting Huang
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi 600, Taiwan
| | - Yu-Qi Zhang
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi 600, Taiwan
| | - Chia-Wen Hsieh
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi 600, Taiwan
| | - Being-Sun Wung
- Department of Microbiology, Immunology and Biopharmaceuticals, National Chiayi University, Chiayi 600, Taiwan.
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10
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Li C, Shi L, Chen D, Ren A, Gao T, Zhao M. Functional analysis of the role of glutathione peroxidase (GPx) in the ROS signaling pathway, hyphal branching and the regulation of ganoderic acid biosynthesis in Ganoderma lucidum. Fungal Genet Biol 2015. [PMID: 26216672 DOI: 10.1016/j.fgb.2015.07.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ganoderma lucidum, a hallmark of traditional Chinese medicine, has been widely used as a pharmacologically active compound. Although numerous research studies have focused on the pharmacological mechanism, fewer studies have explored the basic biological features of this species, restricting the further development and application of this important mushroom. Because of the ability of this mushroom to reduce and detoxify the compounds produced by various metabolic pathways, glutathione peroxidase (GPx) is one of the most important antioxidant enzymes with respect to ROS. Although studies in both animals and plants have suggested many important physiological functions of GPx, there are few systematic research studies concerning the role of this enzyme in fungi, particularly in large basidiomycetes. In the present study, we cloned the GPx gene and created GPx-silenced strains by the down-regulation of GPx gene expression using RNA interference. The results indicated an essential role for GPx in controlling the intracellular H2O2 content, hyphal branching, antioxidant stress tolerance, cytosolic Ca(2+) content and ganoderic acid biosynthesis. Further mechanistic investigation revealed that GPx is regulated by intracellular H2O2 levels and suggested that crosstalk occurs between GPx and intracellular H2O2. Moreover, evidence was obtained indicating that GPx regulation of hyphal branching via ROS might occur independently of the cytosolic Ca(2+) content. Further mechanistic investigation also revealed that the effects of GPx on ganoderic acid synthesis via ROS are regulated by the cytosolic Ca(2+) content. Taken together, these findings indicate that ROS have a complex influence on growth, development and secondary metabolism in fungi and that GPx serves an important function. The present study provides an excellent framework to identify GPx functions and highlights a role for this enzyme in ROS regulation.
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Affiliation(s)
- Chenyang Li
- College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China
| | - Liang Shi
- College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China
| | - Dongdong Chen
- College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China
| | - Ang Ren
- College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China
| | - Tan Gao
- College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China
| | - Mingwen Zhao
- College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Nanjing 210095, Jiangsu, People's Republic of China.
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11
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Rusetskaya NY, Borodulin VB. Biological activity of organoselenium compounds in heavy metal intoxication. BIOCHEMISTRY MOSCOW-SUPPLEMENT SERIES B-BIOMEDICAL CHEMISTRY 2015. [DOI: 10.1134/s1990750815010072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Rusetskaya N, Borodulin V. Biological activity of selenorganic compounds at heavy metal salts intoxication. ACTA ACUST UNITED AC 2015; 61:449-61. [DOI: 10.18097/pbmc20156104449] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Possible mechanisms of the antitoxic action of organoselenium compounds in heavy metal poisoning have been considered. Heavy metal toxicity associated with intensification of free radical oxidation, suppression of the antioxidant system, damage to macromolecules, mitochondria and the genetic material can cause apoptotic cell death or the development of carcinogenesis. Organic selenium compounds are effective antioxidants during heavy metal poisoning; they exhibit higher bioavailability in mammals than inorganic ones and they are able to activate antioxidant defense, bind heavy metal ions and reactive oxygen species formed during metal-induced oxidative stress. One of promising organoselenium compounds is diacetophenonyl selenide (DAPS-25), which is characterized by antioxidant and antitoxic activity, under conditions including heavy metal intoxication
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Affiliation(s)
- N.Y. Rusetskaya
- Razumovskiy Saratov State Medical University, Saratov, Russia
| | - V.B. Borodulin
- Razumovskiy Saratov State Medical University, Saratov, Russia
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13
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Watanabe S, Horie T, Nagao K, Kuwabara Y, Baba O, Nishi H, Sowa N, Narazaki M, Matsuda T, Takemura G, Wada H, Hasegawa K, Kimura T, Ono K. Cardiac-specific inhibition of kinase activity in calcium/calmodulin-dependent protein kinase kinase-β leads to accelerated left ventricular remodeling and heart failure after transverse aortic constriction in mice. PLoS One 2014; 9:e108201. [PMID: 25255457 PMCID: PMC4177887 DOI: 10.1371/journal.pone.0108201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/19/2014] [Indexed: 12/26/2022] Open
Abstract
Background The mechanism of cardiac energy production against sustained pressure overload remains to be elucidated. Methods and Results We generated cardiac-specific kinase-dead (kd) calcium/calmodulin-dependent protein kinase kinase-β (CaMKKβ) transgenic (α-MHC CaMKKβkd TG) mice using α-myosin heavy chain (α-MHC) promoter. Although CaMKKβ activity was significantly reduced, these mice had normal cardiac function and morphology at baseline. Here, we show that transverse aortic binding (TAC) in α-MHC CaMKKβkd TG mice led to accelerated death and left ventricular (LV) dilatation and dysfunction, which was accompanied by significant clinical signs of heart failure. CaMKKβ downstream signaling molecules, including adenosine monophosphate-activated protein kinase (AMPK), were also suppressed in α-MHC CaMKKβkd TG mice compared with wild-type (WT) mice. The expression levels of peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α, which is a downstream target of both of CaMKKβ and calcium/calmodulin kinases, were also significantly reduced in α-MHC CaMKKβkd TG mice compared with WT mice after TAC. In accordance with these findings, mitochondrial morphogenesis was damaged and creatine phosphate/β-ATP ratios assessed by magnetic resonance spectroscopy were suppressed in α-MHC CaMKKβkd TG mice compared with WT mice after TAC. Conclusions These data indicate that CaMKKβ exerts protective effects on cardiac adaptive energy pooling against pressure-overload possibly through phosphorylation of AMPK and by upregulation of PGC-1α. Thus, CaMKKβ may be a therapeutic target for the treatment of heart failure.
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Affiliation(s)
- Shin Watanabe
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahiro Horie
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kazuya Nagao
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuhide Kuwabara
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Osamu Baba
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hitoo Nishi
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Naoya Sowa
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Michiko Narazaki
- Department of Systems Science, Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Tetsuya Matsuda
- Department of Systems Science, Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Genzou Takemura
- Department of Internal Medicine, Asahi University, Gifu, Japan
| | - Hiromichi Wada
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan
| | - Koji Hasegawa
- Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koh Ono
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- * E-mail:
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Yang L, Jia Z, Yang L, Zhu M, Zhang J, Liu J, Wu P, Tian W, Li J, Qi Z, Tang X. Exercise protects against chronic β-adrenergic remodeling of the heart by activation of endothelial nitric oxide synthase. PLoS One 2014; 9:e96892. [PMID: 24809512 PMCID: PMC4014558 DOI: 10.1371/journal.pone.0096892] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 04/13/2014] [Indexed: 01/10/2023] Open
Abstract
Extensive data have shown that exercise training can provide cardio-protection against pathological cardiac hypertrophy. However, how long the heart can retain cardio-protective phenotype after the cessation of exercise is currently unknown. In this study, we investigated the time course of the loss of cardio-protection after cessation of exercise and the signaling molecules that are responsible for the possible sustained protection. Mice were made to run on a treadmill six times a week for 4 weeks and then rested for a period of 0, 1, 2 and 4 weeks followed by isoproterenol injection for 8 days. Morphological, echocardiographic and hemodynamic changes were measured, gene reactivation was determined by real-time PCR, and the expression and phosphorylation status of several cardio-protective signaling molecules were analyzed by Western-blot. HW/BW, HW/TL and LW/BW decreased significantly in exercise training (ER) mice. The less necrosis and lower fetal gene reactivation induced by isoproterenol injection were also found in ER mice. The echocardiographic and hemodynamic changes induced by β-adrenergic overload were also attenuated in ER mice. The protective effects can be sustained for at least 2 weeks after the cessation of the training. Western-blot analysis showed that the alterations in the phosphorylation status of endothelial nitric oxide synthase (eNOS) (increase in serine 1177 and decrease in threonine 495) continued for 2 weeks after the cessation of the training whereas increases of the phosphorylation of Akt and mTOR disappeared. Further study showed that L-NG-Nitroarginine methyl ester (L-NAME) treatment abolished the cardio-protective effects of ER. Our findings demonstrate that stimulation of eNOS in mice through exercise training provides acute and sustained cardioprotection against cardiac hypertrophy.
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Affiliation(s)
- Liang Yang
- Department of Pharmacology, Nankai University School of Medicine, Tianjin, China
| | - Zhe Jia
- Departments of Histology and Embryology, Nankai University School of Medicine, Tianjin, China
| | - Lei Yang
- Departments of Histology and Embryology, Nankai University School of Medicine, Tianjin, China
| | - Mengmeng Zhu
- Departments of Histology and Embryology, Nankai University School of Medicine, Tianjin, China
| | - Jincai Zhang
- Department of Pharmacology, Nankai University School of Medicine, Tianjin, China
| | - Jie Liu
- Department of Pharmacology, Nankai University School of Medicine, Tianjin, China
| | - Ping Wu
- Departments of Histology and Embryology, Nankai University School of Medicine, Tianjin, China
| | - Wencong Tian
- Department of Pharmacology, Nankai University School of Medicine, Tianjin, China
| | - Jing Li
- Department of Pharmacology, Nankai University School of Medicine, Tianjin, China
- * E-mail: (JL); (ZQ)
| | - Zhi Qi
- Departments of Histology and Embryology, Nankai University School of Medicine, Tianjin, China
- * E-mail: (JL); (ZQ)
| | - Xiangdong Tang
- Department of Pharmacology, Nankai University School of Medicine, Tianjin, China
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15
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Hu Z, Xiong Y, Han X, Geng C, Jiang B, Huo Y, Luo J. Acute mechanical stretch promotes eNOS activation in venous endothelial cells mainly via PKA and Akt pathways. PLoS One 2013; 8:e71359. [PMID: 23977025 PMCID: PMC3743752 DOI: 10.1371/journal.pone.0071359] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 06/28/2013] [Indexed: 11/19/2022] Open
Abstract
In the vasculature, physiological levels of nitric oxide (NO) protect against various stressors, including mechanical stretch. While endothelial NO production in response to various stimuli has been studied extensively, the precise mechanism underlying stretch-induced NO production in venous endothelial cells remains incompletely understood. Using a model of continuous cellular stretch, we found that stretch promoted phosphorylation of endothelial NO synthase (eNOS) at Ser1177, Ser633 and Ser615 and NO production in human umbilical vein endothelial cells. Although stretch activated the kinases AMPKα, PKA, Akt, and ERK1/2, stretch-induced eNOS activation was only inhibited by kinase-specific inhibitors of PKA and PI3K/Akt, but not of AMPKα and Erk1/2. Similar results were obtained with knockdown by shRNAs targeting the PKA and Akt genes. Furthermore, inhibition of PKA preferentially attenuated eNOS activation in the early phase, while inhibition of the PI3K/Akt pathway reduced eNOS activation in the late phase, suggesting that the PKA and PI3K/Akt pathways play distinct roles in a time-dependent manner. Finally, we investigated the role of these pathways in stretch-induced endothelial exocytosis and leukocyte adhesion. Interestingly, we found that inhibition of the PI3K/Akt pathway increased stretch-induced Weibel-Palade body exocytosis and leukocyte adhesion, while inhibition of the PKA pathway had the opposite effects, suggesting that the exocytosis-promoting effect of PKA overwhelms the inhibitory effect of PKA-mediated NO production. Taken together, the results suggest that PKA and Akt are important regulators of eNOS activation in venous endothelial cells under mechanical stretch, while playing different roles in the regulation of stretch-induced endothelial exocytosis and leukocyte adhesion.
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Affiliation(s)
- Zhenqian Hu
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Yan Xiong
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Xiaofan Han
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Chenyang Geng
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Beibei Jiang
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Yingqing Huo
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
| | - Jincai Luo
- Laboratory of Vascular Biology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
- * E-mail:
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Piao L, Fang YH, Parikh K, Ryan JJ, Toth PT, Archer SL. Cardiac glutaminolysis: a maladaptive cancer metabolism pathway in the right ventricle in pulmonary hypertension. J Mol Med (Berl) 2013; 91:1185-97. [PMID: 23794090 DOI: 10.1007/s00109-013-1064-7] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 05/09/2013] [Accepted: 06/06/2013] [Indexed: 11/24/2022]
Abstract
UNLABELLED The rapid growth of cancer cells is permitted by metabolic changes, notably increased aerobic glycolysis and increased glutaminolysis. Aerobic glycolysis is also evident in the hypertrophying myocytes in right ventricular hypertrophy (RVH), particularly in association with pulmonary arterial hypertension (PAH). It is unknown whether glutaminolysis occurs in the heart. We hypothesized that glutaminolysis occurs in RVH and assessed the precipitating factors, transcriptional mechanisms, and physiological consequences of this metabolic pathway. RVH was induced in two models, one with PAH (Monocrotaline-RVH) and the other without PAH (pulmonary artery banding, PAB-RVH). Despite similar RVH, ischemia as determined by reductions in RV VEGFα, coronary blood flow, and microvascular density was greater in Monocrotaline-RVH versus PAB-RVH. A sixfold increase in (14)C-glutamine metabolism occurred in Monocrotaline-RVH but not in PAB-RVH. In the RV working heart model, the glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON) decreased glutaminolysis, caused a reciprocal increase in glucose oxidation, and elevated cardiac output. Consistent with the increased glutaminolysis in RVH, RV expressions of glutamine transporters (SLC1A5 and SLC7A5) and mitochondrial malic enzyme were elevated (Monocrotaline-RVH > PAB-RVH > control). Capillary rarefaction and glutamine transporter upregulation also occurred in RVH in patients with PAH. cMyc and Max, known to mediate transcriptional upregulation of glutaminolysis, were increased in Monocrotaline-RVH. In vivo, DON (0.5 mg/kg/day × 3 weeks) restored pyruvate dehydrogenase activity, reduced RVH, and increased cardiac output (89 ± 8, vs. 55 ± 13 ml/min, p < 0.05) and treadmill distance (194 ± 71, vs. 36 ±7 m, p < 0.05) in Monocrotaline-RVH. Glutaminolysis is induced in the RV in PAH by cMyc-Max, likely as a consequence of RV ischemia. Inhibition of glutaminolysis restores glucose oxidation and has a therapeutic benefit in vivo. KEY MESSAGE Patients with pulmonary artery hypertension (PAH) have evidence of cardiac glutaminolysis. Cardiac glutaminolysis is associated with microvascular rarefaction/ischemia. As in cancer, cardiac glutaminolysis results from activation of cMyc-Max. The specific glutaminolysis inhibitor DON regresses right ventricular hypertrophy. DON improves cardiac function and exercise capacity in an animal model of PAH.
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Affiliation(s)
- Lin Piao
- Section of Cardiology, Department of Medicine, University of Chicago, Chicago, IL, USA
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