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Udjus C, Sjaastad I, Hjørnholm U, Tunestveit TK, Hoffmann P, Hinojosa A, Espe EKS, Christensen G, Skjønsberg OH, Larsen KO, Rostrup M. Extreme altitude induces divergent mass reduction of right and left ventricle in mountain climbers. Physiol Rep 2022; 10:e15184. [PMID: 35146955 PMCID: PMC8831961 DOI: 10.14814/phy2.15184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/31/2021] [Accepted: 01/13/2022] [Indexed: 12/01/2022] Open
Abstract
Mountain climbing at high altitude implies exposure to low levels of oxygen, low temperature, wind, physical and psychological stress, and nutritional insufficiencies. We examined whether right ventricular (RV) and left ventricular (LV) myocardial masses were reversibly altered by exposure to extreme altitude. Magnetic resonance imaging and echocardiography of the heart, dual x‐ray absorptiometry scan of body composition, and blood samples were obtained from ten mountain climbers before departure to Mount Everest or Dhaulagiri (baseline), 13.5 ± 1.5 days after peaking the mountain (post‐hypoxia), and six weeks and six months after expeditions exceeding 8000 meters above sea level. RV mass was unaltered after extreme altitude, in contrast to a reduction in LV mass by 11.8 ± 3.4 g post‐hypoxia (p = 0.001). The reduction in LV mass correlated with a reduction in skeletal muscle mass. After six weeks, LV myocardial mass was restored to baseline values. Extreme altitude induced a reduction in LV end‐diastolic volume (20.8 ± 7.7 ml, p = 0.011) and reduced E’, indicating diastolic dysfunction, which were restored after six weeks follow‐up. Elevated circulating interleukin‐18 after extreme altitude compared to follow‐up levels, might have contributed to reduced muscle mass and diastolic dysfunction. In conclusion, the mass of the RV, possibly exposed to elevated afterload, was not changed after extreme altitude, whereas LV mass was reduced. The reduction in LV mass correlated with reduced skeletal muscle mass, indicating a common denominator, and elevated circulating interleukin‐18 might be a mechanism for reduced muscle mass after extreme altitude.
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Affiliation(s)
- Camilla Udjus
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål, Oslo, Norway.,Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway.,Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway
| | - Ulla Hjørnholm
- Section of Cardiovascular and Renal Research, Medical Division, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway
| | - Torbjørn K Tunestveit
- Section of Cardiovascular and Renal Research, Medical Division, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.,University of Oslo, Oslo, Norway
| | - Pavel Hoffmann
- Section for Interventional Cardiology, Division of Cardiovascular and Pulmonary Diseases, Department of Cardiology, Oslo University Hospital, Oslo, Norway
| | - Alexis Hinojosa
- Department of Radiology and Nuclear Medicine, Oslo University Hospital Ullevål, Oslo, Norway.,Interventional Centre (IVS), Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Emil K S Espe
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Ole H Skjønsberg
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål, Oslo, Norway.,Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Karl-Otto Larsen
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål, Oslo, Norway
| | - Morten Rostrup
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Section of Cardiovascular and Renal Research, Medical Division, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.,Department of Acute Medicine, Oslo University Hospital, Oslo, Norway
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2
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Naryzhnaya NV, Ma HJ, Maslov LN. The involvement of protein kinases in the cardioprotective effect of chronic hypoxia. Physiol Res 2020; 69:933-945. [PMID: 33129243 DOI: 10.33549/physiolres.934439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The purpose of this review is to analyze the involvement of protein kinases in the cardioprotective mechanism induced by chronic hypoxia. It has been reported that chronic intermittent hypoxia contributes to increased expression of the following kinases in the myocardium: PKCdelta, PKCalpha, p-PKCepsilon, p-PKCalpha, AMPK, p-AMPK, CaMKII, p-ERK1/2, p-Akt, PI3-kinase, p-p38, HK-1, and HK-2; whereas, chronic normobaric hypoxia promotes increased expression of the following kinases in the myocardium: PKCepsilon, PKCbetaII, PKCeta, CaMKII, p-ERK1/2, p-Akt, p-p38, HK-1, and HK-2. However, CNH does not promote enhanced expression of the AMPK and JNK kinases. Adaptation to hypoxia enhances HK-2 association with mitochondria and causes translocation of PKCdelta, PKCbetaII, and PKCeta to the mitochondria. It has been shown that PKCdelta, PKCepsilon, ERK1/2, and MEK1/2 are involved in the cardioprotective effect of chronic hypoxia. The role of other kinases in the cardioprotective effect of adaptation to hypoxia requires further research.
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Affiliation(s)
- N V Naryzhnaya
- Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia.
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3
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Vitali SH, Fernandez-Gonzalez A, Nadkarni J, Kwong A, Rose C, Mitsialis SA, Kourembanas S. Heme oxygenase-1 dampens the macrophage sterile inflammasome response and regulates its components in the hypoxic lung. Am J Physiol Lung Cell Mol Physiol 2019; 318:L125-L134. [PMID: 31664855 DOI: 10.1152/ajplung.00074.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Exposure to hypoxia causes an inflammatory reaction in the mouse lung, and this response can be modulated by overexpressing the hypoxia-inducible stress-response enzyme, heme oxygenase-1 (HO-1). We hypothesized that the inflammasome activity may be a central pathway by which HO-1 controls pulmonary inflammation following alveolar hypoxia. Therefore, we investigated whether HO-1 controls inflammasome activation by altering its expression in macrophages primed with classic NOD-like receptor containing a pyrin domain 3 (NLRP3) inducers, and in murine lungs lacking HO-1 and exposed to acute hypoxia. We found that lack of HO-1 activated lipopolysaccharide (LPS) and ATP-treated bone marrow-derived macrophages, causing an increase in secreted levels of cleaved interleukin (IL)-1B, IL-18, and caspase-1, markers of increased inflammasome activity, whereas HO-1 overexpression suppressed IL-1B, NLRP3, and IL-18. The production of cleaved IL-1B and the activation of caspase-1 in LPS- and ATP-primed macrophages were inhibited by hemin, an HO-1 inducer, and two HO-1 enzymatic products [bilirubin and carbon monoxide (CO)]. Exposure of mice to hypoxia induced the expression of several inflammasome mRNA components (IL-1B, Nlrp3, and caspase-1), and this was further augmented by HO-1 deficiency. This pronounced inflammasome activation was detected as increased protein levels of apoptosis-associated speck-like protein containing a COOH-terminal caspase recruitment domain, IL-18, procaspase-1, and cleaved caspase-1 in the lungs of hypoxic mice. Systemically, Hmox1-deficient mice showed increased basal levels of IL-18 that were further increased after 48 h of hypoxic exposure. Taken together, these finding point to a pivotal role for HO-1 in the control of baseline and hypoxic inflammasome signaling, perhaps through the antioxidant properties of bilirubin and CO's pleiotropic effects.
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Affiliation(s)
- Sally H Vitali
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Division of Critical Care Medicine, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts.,Department of Anesthesia, Harvard Medical School, Boston, Massachusetts
| | - Angeles Fernandez-Gonzalez
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Janhavi Nadkarni
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Division of Critical Care Medicine, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts
| | - April Kwong
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Division of Critical Care Medicine, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts
| | - Chase Rose
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Division of Critical Care Medicine, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, Massachusetts
| | - S Alex Mitsialis
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Stella Kourembanas
- Division of Newborn Medicine & Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
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4
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Elgenaidi IS, Spiers JP. Hypoxia modulates protein phosphatase 2A through HIF-1α dependent and independent mechanisms in human aortic smooth muscle cells and ventricular cardiomyocytes. Br J Pharmacol 2019; 176:1745-1763. [PMID: 30825189 DOI: 10.1111/bph.14648] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 02/05/2019] [Accepted: 02/13/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Although protein phosphatases regulate multiple cellular functions, their modulation under hypoxia remains unclear. We investigated expression of the protein phosphatase system under normoxic/hypoxic conditions and the mechanism by which hypoxia alters protein phosphatase 2A (PP2A) activity. EXPERIMENTAL APPROACH Human cardiovascular cells were cultured in cell type specific media under normoxic or hypoxic conditions (1% O2 ). Effects on mRNA expression, phosphatase activity, post-translational modification, and involvement of hypoxia inducible factor 1α (HIF-1α) were assessed using RT-PCR, immunoblotting, an activity assay, and siRNA silencing. KEY RESULTS All components of the protein phosphatase system studied were expressed in each cell line. Hypoxia attenuated mRNA expression of the transcripts in a cell line- and time-dependent manner. In human aortic smooth muscle cells (HASMC) and AC16 cells, hypoxia decreased PP2Ac activity and mRNA expression without altering PP2Ac abundance. Hypoxia increased demethylated PP2Ac (DPP2Ac) and phosphatase methylesterase 1 (PME-1) abundance but decreased leucine carboxyl methyltransferase 1 (LCMT-1) abundance. HIF-1α siRNA prevented the hypoxia-mediated decrease in phosphatase activity and expression of the catalytic subunit of protein phosphatase 2A (PPP2CA), independently of altering pPP2Ac, DPP2Ac, LCMT-1, or PME-1 abundance. CONCLUSION AND IMPLICATIONS Cardiovascular cells express multiple components of the PP2A system. In HASMC and AC16 cells, hypoxia inhibits PP2A activity through HIF-1α-dependent and -independent mechanisms, with the latter being consistent with altered PP2A holoenzyme assembly. This indicates a complex inhibitory effect of hypoxia on the PP2A system, and highlights PP2A as a therapeutic target for diseases associated with dysregulated protein phosphorylation.
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Affiliation(s)
| | - James Paul Spiers
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Dublin, Ireland
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5
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Udjus C, Cero FT, Halvorsen B, Behmen D, Carlson CR, Bendiksen BA, Espe EKS, Sjaastad I, Løberg EM, Yndestad A, Aukrust P, Christensen G, Skjønsberg OH, Larsen KO. Caspase-1 induces smooth muscle cell growth in hypoxia-induced pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2019; 316:L999-L1012. [PMID: 30908936 DOI: 10.1152/ajplung.00322.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Lung diseases with hypoxia are complicated by pulmonary hypertension, leading to heart failure and death. No pharmacological treatment exists. Increased proinflammatory cytokines are found in hypoxic patients, suggesting an inflammatory pathogenesis. Caspase-1, the effector of the inflammasome, mediates inflammation through activation of the proinflammatory cytokines interleukin (IL)-18 and IL-1β. Here, we investigate inflammasome-related mechanisms that can trigger hypoxia-induced pulmonary hypertension. Our aim was to examine whether caspase-1 induces development of hypoxia-related pulmonary hypertension and is a suitable target for therapy. Wild-type (WT) and caspase-1-/- mice were exposed to 10% oxygen for 14 days. Hypoxic caspase-1-/- mice showed lower pressure and reduced muscularization in pulmonary arteries, as well as reduced right ventricular remodeling compared with WT. Smooth muscle cell (SMC) proliferation was reduced in caspase-1-deficient pulmonary arteries and in WT arteries treated with a caspase-1 inhibitor. Impaired inflammation was shown in hypoxic caspase-1-/- mice by abolished pulmonary influx of immune cells and lower levels of IL-18, IL-1β, and IL-6, which were also reduced in the medium surrounding caspase-1 abrogated pulmonary arteries. By adding IL-18 or IL-1β to caspase-1-deficient pulmonary arteries, SMC proliferation was retained. Furthermore, inhibition of both IL-6 and phosphorylated STAT3 reduced proliferation of SMC in vitro, indicating IL-18, IL-6, and STAT3 as downstream mediators of caspase-1-induced SMC proliferation in pulmonary arteries. Caspase-1 induces SMC proliferation in pulmonary arteries through the caspase-1/IL-18/IL-6/STAT3 pathway, leading to pulmonary hypertension in mice exposed to hypoxia. We propose that caspase-1 inhibition is a potential target for treatment of pulmonary hypertension.
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Affiliation(s)
- Camilla Udjus
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Fadila T Cero
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Bente Halvorsen
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo , Oslo , Norway
| | - Dina Behmen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Cathrine R Carlson
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Bård A Bendiksen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Emil K S Espe
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Else M Løberg
- Department of Pathology, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway
| | - Arne Yndestad
- K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway.,Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo , Oslo , Norway
| | - Pål Aukrust
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo , Oslo , Norway.,Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet and University of Oslo , Oslo , Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
| | - Ole H Skjønsberg
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway
| | - Karl-Otto Larsen
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo , Oslo , Norway.,K. G. Jebsen Center for Cardiac Research and Center for Heart Failure Research, University of Oslo , Oslo , Norway
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6
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Elgenaidi IS, Spiers JP. Regulation of the phosphoprotein phosphatase 2A system and its modulation during oxidative stress: A potential therapeutic target? Pharmacol Ther 2019; 198:68-89. [PMID: 30797822 DOI: 10.1016/j.pharmthera.2019.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 02/15/2019] [Indexed: 02/06/2023]
Abstract
Phosphoprotein phosphatases are of growing interest in the pathophysiology of many diseases and are often the neglected partner of protein kinases. One family member, PP2A, accounts for dephosphorylation of ~55-70% of all serine/threonine phosphosites. Interestingly, dysregulation of kinase signalling is a hallmark of many diseases in which an increase in oxidative stress is also noted. With this in mind, we assess the evidence to support oxidative stress-mediated regulation of the PP2A system In this article, we first present an overview of the PP2A system before providing an analysis of the regulation of PP2A by endogenous inhibitors, post translational modification, and miRNA. Next, a detailed critique of data implicating reactive oxygen species, ischaemia, ischaemia-reperfusion, and hypoxia in regulating the PP2A holoenzyme and associated regulators is presented. Finally, the pharmacological targeting of PP2A, its endogenous inhibitors, and enzymes responsible for its post-translational modification are covered. There is extensive evidence that oxidative stress modulates multiple components of the PP2A system, however, most of the data pertains to the catalytic subunit of PP2A. Irrespective of the underlying aetiology, free radical-mediated attenuation of PP2A activity is an emerging theme. However, in many instances, a dichotomy exists, which requires clarification and mechanistic insight. Nevertheless, this raises the possibility that pharmacological activation of PP2A, either through small molecule activators of PP2A or CIP2A/SET antagonists may be beneficial in modulating the cellular response to oxidative stress. A better understanding of which, will have wide ranging implications for cancer, heart disease and inflammatory conditions.
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Affiliation(s)
- I S Elgenaidi
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Ireland
| | - J P Spiers
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Ireland.
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7
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Luks AM, Levett D, Martin DS, Goss CH, Mitchell K, Fernandez BO, Feelisch M, Grocott MP, Swenson ER. Changes in acute pulmonary vascular responsiveness to hypoxia during a progressive ascent to high altitude (5300 m). Exp Physiol 2017; 102:711-724. [PMID: 28390080 DOI: 10.1113/ep086083] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 04/03/2017] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do the pulmonary vascular responses to hypoxia change during progressive exposure to high altitude and can alterations in these responses be related to changes in concentrations of circulating biomarkers that affect the pulmonary circulation? What is the main finding and its importance? In our field study with healthy volunteers, we demonstrate changes in pulmonary artery pressure suggestive of remodelling in the pulmonary circulation, but find no changes in the acute responsiveness of the pulmonary circulation to changes in oxygenation during 2 weeks of exposure to progressive hypoxia. Pulmonary artery pressure changes were associated with changes in erythropoietin, 8-isoprostane, nitrite and guanosine 3',5'-cyclic monophosphate. We sought to determine whether changes in pulmonary artery pressure responses to hypoxia suggestive of vascular remodelling occur during progressive exposure to high altitude and whether such alterations are related to changes in concentrations of circulating biomarkers with known or suspected actions on the pulmonary vasculature during ascent. We measured tricuspid valve transvalvular pressure gradients (TVPG) in healthy volunteers breathing air at sea level (London, UK) and in hypoxic conditions simulating the inspired O2 partial pressures at two locations in Nepal, Namche Bazaar (NB, elevation 3500 m) and Everest Base Camp (EBC, elevation 5300 m). During a subsequent 13 day trek, TVPG was measured at NB and EBC while volunteers breathed air and hyperoxic or hypoxic mixtures simulating the inspired O2 partial pressures at the other locations. For each location, we determined the slope of the relationship between TVPG and arterial oxygen saturation (SaO2) to estimate the pulmonary vascular response to hypoxia. Mean TVPG breathing air was higher at any SaO2 at EBC than at sea level or NB, but there was no change in the slope of the relationship between SaO2 and TVPG between locations. Nitric oxide availability remained unchanged despite increases in oxidative stress (elevated 8-isoprostane). Erythropoietin, pro-atrial natriuretic peptide and interleukin-18 levels progressively increased on ascent. Associations with TVPG were observed only with erythropoietin, 8-isoprostane, nitrite and guanosine 3',5'-cyclic monophosphate. Although the increased TVPG for any given SaO2 at EBC suggests that pulmonary vascular remodelling might occur during 2 weeks of progressive hypoxia, the lack of change in the slope of the relationship between TVPG and SaO2 indicates that the acute pulmonary vascular responsiveness to changes in oxygenation does not vary within this time frame.
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Affiliation(s)
- Andrew M Luks
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Denny Levett
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK.,Anaesthesia and Critical Care Research Unit, University Hospital Southampton National Health Service Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Daniel S Martin
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK
| | | | - Kay Mitchell
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK.,Anaesthesia and Critical Care Research Unit, University Hospital Southampton National Health Service Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Bernadette O Fernandez
- Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK.,Warwick Medical School, University of Warwick, Coventry, UK
| | - Martin Feelisch
- Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK.,Warwick Medical School, University of Warwick, Coventry, UK
| | - Michael P Grocott
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK.,Anaesthesia and Critical Care Research Unit, University Hospital Southampton National Health Service Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Erik R Swenson
- Department of Medicine, University of Washington, Seattle, WA, USA.,Medical Service, Veterans Affairs (VA) Puget Sound Health Care System, Seattle, WA, USA
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8
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Okuhara Y, Yokoe S, Iwasaku T, Eguchi A, Nishimura K, Li W, Oboshi M, Naito Y, Mano T, Asahi M, Okamura H, Masuyama T, Hirotani S. Interleukin-18 gene deletion protects against sepsis-induced cardiac dysfunction by inhibiting PP2A activity. Int J Cardiol 2017; 243:396-403. [PMID: 28526544 DOI: 10.1016/j.ijcard.2017.04.082] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/20/2017] [Accepted: 04/24/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND Interleukin-18 (IL-18) neutralization protects against lipopolysaccharide (LPS)-induced injuries, including myocardial dysfunction. However, the mechanism is yet to be fully elucidated. The aim of the present study was to determine whether IL-18 gene deletion prevents sepsis-induced cardiac dysfunction and to elucidate the potential mechanisms underlying IL-18-mediated cardiotoxicity by LPS. METHODS AND RESULTS Ten-week-old male wild-type (WT) and IL-18 knockout (IL-18 KO) mice were intraperitoneally administered LPS. Serial echocardiography showed better systolic pump function and less left ventricular (LV) dilatation in LPS-treated IL-18 KO mice compared with those in LPS-treated WT mice. LPS treatment significantly decreased the levels of phospholamban (PLN) and Akt phosphorylation in WT mice compared with those in saline-treated WT mice, while the LPS-induced decrease in the phosphorylation levels was attenuated in IL-18 KO mice compared with that in WT mice. IL-18 gene deletion also attenuated an LPS-induced increase of type 2 protein phosphatase 2A (PP2A) activity, a molecule that dephosphorylates PLN and Akt. There was no difference in type 1 protein phosphatase (PP1) activity. To address whether IL-18 affects PLN and Akt phosphorylation via PP2A activation in cardiomyocytes, rat neonatal cardiac myocytes were cultured and stimulated using 100ng/ml of recombinant rat IL-18. Exogenous IL-18 decreased the level of PLN and Akt phosphorylation in cardiomyocytes. PP2A activity but not PP1 activity was increased by IL-18 stimulation in cardiomyocytes. CONCLUSIONS IL-18 plays a pivotal role in advancing sepsis-induced cardiac dysfunction, and the mechanisms underlying IL-18-mediated cardiotoxicity potentially involve the regulation of PLN and Akt phosphorylation through PP2A activity.
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Affiliation(s)
- Yoshitaka Okuhara
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Shunichi Yokoe
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Osaka, Japan
| | - Toshihiro Iwasaku
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Akiyo Eguchi
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Koichi Nishimura
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Wen Li
- Laboratory of Tumor Immunology and Cell Therapy, Hyogo College of Medicine, Nishinomiya, Japan
| | - Makiko Oboshi
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Yoshiro Naito
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Toshiaki Mano
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Michio Asahi
- Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Osaka, Japan
| | - Haruki Okamura
- Laboratory of Tumor Immunology and Cell Therapy, Hyogo College of Medicine, Nishinomiya, Japan
| | - Tohru Masuyama
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Shinichi Hirotani
- Cardiovascular Division, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
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9
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Lorenzen-Schmidt I, Clarke SB, Pyle WG. The neglected messengers: Control of cardiac myofilaments by protein phosphatases. J Mol Cell Cardiol 2016; 101:81-89. [PMID: 27721025 DOI: 10.1016/j.yjmcc.2016.10.002] [Citation(s) in RCA: 10] [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: 08/05/2016] [Revised: 10/03/2016] [Accepted: 10/05/2016] [Indexed: 01/21/2023]
Abstract
Cardiac myofilaments act as the central contractile apparatus of heart muscle cells. Covalent modification of constituent proteins through phosphorylation is a rapid and powerful mechanism to control myofilament function, and is increasingly seen as a mechanism of disease. While the relationship between protein kinases and cardiac myofilaments has been widely examined, the impact of protein dephosphorylation by protein phosphatases is poorly understood. This review outlines the mechanisms by which the mostly widely expressed protein phosphatases in cardiac myocytes regulate myofilament function, and the emerging role of myofilament-associated protein phosphatases in heart failure. The importance of regulatory subunits and subcellular compartmentalization in determining the functional impact of protein phosphatases on myofilament and myocardial function is also discussed, as are discrepancies about the roles of protein phosphatases in regulating myofilament function. The potential for targeting these molecular messengers in the treatment of heart failure is discussed as a key future direction.
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Affiliation(s)
- Ilka Lorenzen-Schmidt
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Samantha B Clarke
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - W Glen Pyle
- Centre for Cardiovascular Investigations, Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
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10
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Cero FT, Hillestad V, Sjaastad I, Yndestad A, Aukrust P, Ranheim T, Lunde IG, Olsen MB, Lien E, Zhang L, Haugstad SB, Løberg EM, Christensen G, Larsen KO, Skjønsberg OH. Absence of the inflammasome adaptor ASC reduces hypoxia-induced pulmonary hypertension in mice. Am J Physiol Lung Cell Mol Physiol 2015; 309:L378-87. [PMID: 26071556 DOI: 10.1152/ajplung.00342.2014] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 06/08/2015] [Indexed: 12/16/2022] Open
Abstract
Pulmonary hypertension is a serious condition that can lead to premature death. The mechanisms involved are incompletely understood although a role for the immune system has been suggested. Inflammasomes are part of the innate immune system and consist of the effector caspase-1 and a receptor, where nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) is the best characterized and interacts with the adaptor protein apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC). To investigate whether ASC and NLRP3 inflammasome components are involved in hypoxia-induced pulmonary hypertension, we utilized mice deficient in ASC and NLRP3. Active caspase-1, IL-18, and IL-1β, which are regulated by inflammasomes, were measured in lung homogenates in wild-type (WT), ASC(-/-), and NLRP3(-/-) mice, and phenotypical changes related to pulmonary hypertension and right ventricular remodeling were characterized after hypoxic exposure. Right ventricular systolic pressure (RVSP) of ASC(-/-) mice was significantly lower than in WT exposed to hypoxia (40.8 ± 1.5 mmHg vs. 55.8 ± 2.4 mmHg, P < 0.001), indicating a substantially reduced pulmonary hypertension in mice lacking ASC. Magnetic resonance imaging further supported these findings by demonstrating reduced right ventricular remodeling. RVSP of NLRP3(-/-) mice exposed to hypoxia was not significantly altered compared with WT hypoxia. Whereas hypoxia increased protein levels of caspase-1, IL-18, and IL-1β in WT and NLRP3(-/-) mice, this response was absent in ASC(-/-) mice. Moreover, ASC(-/-) mice displayed reduced muscularization and collagen deposition around arteries. In conclusion, hypoxia-induced elevated right ventricular pressure and remodeling were attenuated in mice lacking the inflammasome adaptor protein ASC, suggesting that inflammasomes play an important role in the pathogenesis of pulmonary hypertension.
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Affiliation(s)
- Fadila Telarevic Cero
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway;
| | - Vigdis Hillestad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; K.G. Jebsen Inflammation Research Center, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Arne Yndestad
- Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway; K.G. Jebsen Inflammation Research Center, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Pål Aukrust
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway; K.G. Jebsen Inflammation Research Center, Faculty of Medicine, University of Oslo, Oslo, Norway; Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Trine Ranheim
- Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway; K.G. Jebsen Inflammation Research Center, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ida Gjervold Lunde
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Maria Belland Olsen
- Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet and University of Oslo, Oslo, Norway
| | - Egil Lien
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts; Centre of Inflammation Research, Department of Cancer Research and Molecular Medicine, NTNU, Trondheim, Norway
| | - Lili Zhang
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
| | - Solveig Bjærum Haugstad
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
| | - Else Marit Løberg
- Department of Pathology, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
| | - Karl-Otto Larsen
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway; Center for Heart Failure Research, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
| | - Ole Henning Skjønsberg
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål and University of Oslo, Oslo, Norway
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11
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Toldo S, Abbate A. Diastolic dysfunction in chronic hypoxia: IL-18 provides the elusive link. Acta Physiol (Oxf) 2015; 213:298-300. [PMID: 25293945 DOI: 10.1111/apha.12403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- S. Toldo
- VCU Pauley Heart Center; Virginia Commonwealth University; Richmond VA USA
- Victoria Johnson Research Laboratory; Virginia Commonwealth University; Richmond VA USA
| | - A. Abbate
- VCU Pauley Heart Center; Virginia Commonwealth University; Richmond VA USA
- Victoria Johnson Research Laboratory; Virginia Commonwealth University; Richmond VA USA
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12
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Hillestad V, Espe EKS, Cero F, Larsen KO, Sjaastad I, Nygård S, Skjønsberg OH, Christensen G. IL-18 neutralization during alveolar hypoxia improves left ventricular diastolic function in mice. Acta Physiol (Oxf) 2015; 213:492-504. [PMID: 25182570 DOI: 10.1111/apha.12376] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 06/30/2014] [Accepted: 08/27/2014] [Indexed: 12/18/2022]
Abstract
AIM In patients, an association exists between pulmonary diseases and diastolic dysfunction of the left ventricle (LV). We have previously shown that alveolar hypoxia in mice induces LV diastolic dysfunction and that mice exposed to hypoxia have increased levels of circulating interleukin-18 (IL-18), suggesting involvement of IL-18 in development of diastolic dysfunction. IL-18 binding protein (IL-18BP) is a natural inhibitor of IL-18. In this study, we hypothesized that neutralization of IL-18 during alveolar hypoxia would improve LV diastolic function. METHODS Mice were exposed to 10% oxygen for 2 weeks while treated with IL-18BP or vehicle. Cardiac function and morphology were measured using echocardiography, intraventricular pressure measurements and magnetic resonance imaging (MRI). For characterization of molecular changes in the heart, both real-time PCR and Western blotting were performed. ELISA technique was used to measure levels of circulating cytokines. RESULTS As expected, exposure to hypoxia-induced LV diastolic dysfunction, as shown by prolonged time constant of isovolumic relaxation (τ). Improved relaxation with IL-18BP treatment was demonstrated by a significant reduction towards control τ values. Decreased levels of phosphorylated phospholamban (P-PLB) in hypoxia, but normalization by IL-18BP treatment suggest a role for IL-18 in regulation of calcium-handling proteins in hypoxia-induced diastolic dysfunction. In addition, MRI showed less increase in right ventricular (RV) wall thickness in IL-18BP-treated animals exposed to hypoxia, indicating an effect on RV hypertrophy. CONCLUSION Neutralization of IL-18 during alveolar hypoxia improves LV diastolic function and partly prevents RV hypertrophy.
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Affiliation(s)
- V. Hillestad
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
| | - E. K. S. Espe
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
| | - F. Cero
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
- Departement of Pulmonary Medicine; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
| | - K. O. Larsen
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
- Departement of Pulmonary Medicine; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
| | - I. Sjaastad
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
| | - S. Nygård
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
- Bioinformatics Core Facility; Institute for Medical Informatics; Oslo University Hospital and University of Oslo; Oslo Norway
| | - O. H. Skjønsberg
- Departement of Pulmonary Medicine; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
| | - G. Christensen
- Institute for Experimental Medical Research; Oslo University Hospital Ullevål and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center; University of Oslo; Oslo Norway
- Center for Heart Failure Research; University of Oslo; Oslo Norway
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13
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Kirchhefer U, Brekle C, Eskandar J, Isensee G, Kučerová D, Müller FU, Pinet F, Schulte JS, Seidl MD, Boknik P. Cardiac function is regulated by B56α-mediated targeting of protein phosphatase 2A (PP2A) to contractile relevant substrates. J Biol Chem 2014; 289:33862-73. [PMID: 25320082 DOI: 10.1074/jbc.m114.598938] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dephosphorylation of important myocardial proteins is regulated by protein phosphatase 2A (PP2A), representing a heterotrimer that is comprised of catalytic, scaffolding, and regulatory (B) subunits. There is a multitude of B subunit family members directing the PP2A holoenzyme to different myocellular compartments. To gain a better understanding of how these B subunits contribute to the regulation of cardiac performance, we generated transgenic (TG) mice with cardiomyocyte-directed overexpression of B56α, a phosphoprotein of the PP2A-B56 family. The 2-fold overexpression of B56α was associated with an enhanced PP2A activity that was localized mainly in the cytoplasm and myofilament fraction. Contractility was enhanced both at the whole heart level and in isolated cardiomyocytes of TG compared with WT mice. However, peak amplitude of [Ca]i did not differ between TG and WT cardiomyocytes. The basal phosphorylation of cardiac troponin inhibitor (cTnI) and the myosin-binding protein C was reduced by 26 and 35%, respectively, in TG compared with WT hearts. The stimulation of β-adrenergic receptors by isoproterenol (ISO) resulted in an impaired contractile response of TG hearts. At a depolarizing potential of -5 mV, the ICa,L current density was decreased by 28% after administration of ISO in TG cardiomyocytes. In addition, the ISO-stimulated phosphorylation of phospholamban at Ser(16) was reduced by 27% in TG hearts. Thus, the increased PP2A-B56α activity in TG hearts is localized to specific subcellular sites leading to the dephosphorylation of important contractile proteins. This may result in higher myofilament Ca(2+) sensitivity and increased basal contractility in TG hearts. These effects were reversed by β-adrenergic stimulation.
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Affiliation(s)
- Uwe Kirchhefer
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Christiane Brekle
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - John Eskandar
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Gunnar Isensee
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Dana Kučerová
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Frank U Müller
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Florence Pinet
- INSERM, U744, Institut Pasteur de Lille, 59019 Lille, France
| | - Jan S Schulte
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Matthias D Seidl
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
| | - Peter Boknik
- From the Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, D-48149 Münster, Germany and
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14
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O'Donnell DE, Laveneziana P, Webb K, Neder JA. Chronic obstructive pulmonary disease: clinical integrative physiology. Clin Chest Med 2013; 35:51-69. [PMID: 24507837 DOI: 10.1016/j.ccm.2013.09.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peripheral airway dysfunction, inhomogeneous ventilation distribution, gas trapping, and impaired pulmonary gas exchange are variably present in all stages of chronic obstructive pulmonary disease (COPD). This article provides a cogent physiologic explanation for the relentless progression of activity-related dyspnea and exercise intolerance that all too commonly characterizes COPD. The spectrum of physiologic derangements that exist in smokers with mild airway obstruction and a history compatible with COPD is examined. Also explored are the perceptual and physiologic consequences of progressive erosion of the resting inspiratory capacity. Finally, emerging information on the role of cardiocirculatory impairment in contributing to exercise intolerance in patients with varying degrees of airway obstruction is reviewed.
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Affiliation(s)
- Denis E O'Donnell
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, Ontario K7L 2V6, Canada.
| | - Pierantonio Laveneziana
- Service d'Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée Hôpital Universitaire Pitié-Salpêtrière (AP-HP), Laboratoire de Physio-Pathologie Respiratoire, Faculty of Medicine, Pierre et Marie Curie University (Paris VI), 47-83 Boulevard de l'Hôpital,75013 Paris, France
| | - Katherine Webb
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, Ontario K7L 2V6, Canada
| | - J Alberto Neder
- Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, 102 Stuart Street, Kingston, Ontario K7L 2V6, Canada
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15
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Anthrax lethal toxin induces acute diastolic dysfunction in rats through disruption of the phospholamban signaling network. Int J Cardiol 2013; 168:3884-95. [PMID: 23907041 DOI: 10.1016/j.ijcard.2013.06.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 05/09/2013] [Accepted: 06/28/2013] [Indexed: 01/08/2023]
Abstract
BACKGROUND Anthrax lethal toxin (LT), secreted by Bacillus anthracis, causes severe cardiac dysfunction by unknown mechanisms. LT specifically cleaves the docking domains of MAPKK (MEKs); thus, we hypothesized that LT directly impairs cardiac function through dysregulation of MAPK signaling mechanisms. METHODS AND RESULTS In a time-course study of LT toxicity, echocardiography revealed acute diastolic heart failure accompanied by pulmonary regurgitation and left atrial dilation in adult Sprague-Dawley rats at time points corresponding to dysregulated JNK, phospholamban (PLB) and protein phosphatase 2A (PP2A) myocardial signaling. Using isolated rat ventricular myocytes, we identified the MEK7-JNK1-PP2A-PLB signaling axis to be important for regulation of intracellular calcium (Ca(2+)(i)) handling, PP2A activation and targeting of PP2A-B56α to Ca(2+)(i) handling proteins, such as PLB. Through a combination of gain-of-function and loss-of-function studies, we demonstrated that over-expression of MEK7 protects against LT-induced PP2A activation and Ca(2+)(i) dysregulation through activation of JNK1. Moreover, targeted phosphorylation of PLB-Thr(17) by Akt improved sarcoplasmic reticulum Ca(2+)(i) release and reuptake during LT toxicity. Co-immunoprecipitation experiments further revealed the pivotal role of MEK7-JNK-Akt complex formation for phosphorylation of PLB-Thr(17) during acute LT toxicity. CONCLUSIONS Our findings support a cardiogenic mechanism of LT-induced diastolic dysfunction, by which LT disrupts JNK1 signaling and results in Ca(2+)(i) dysregulation through diminished phosphorylation of PLB by Akt and increased dephosphorylation of PLB by PP2A. Integration of the MEK7-JNK1 signaling module with Akt represents an important stress-activated signalosome that may confer protection to sustain cardiac contractility and maintain normal levels of Ca(2+)(i) through PLB-T(17) phosphorylation.
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16
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Safronova OS. Post-translational modifications of proteins in gene regulation under hypoxic conditions. Inflamm Regen 2013. [DOI: 10.2492/inflammregen.33.203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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17
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The cardiac ventricular 5-HT4 receptor is functional in late foetal development and is reactivated in heart failure. PLoS One 2012; 7:e45489. [PMID: 23029047 PMCID: PMC3447799 DOI: 10.1371/journal.pone.0045489] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 08/23/2012] [Indexed: 11/20/2022] Open
Abstract
A positive inotropic responsiveness to serotonin, mediated by 5-HT4 and 5-HT2A receptors, appears in the ventricle of rats with post-infarction congestive heart failure (HF) and pressure overload-induced hypertrophy. A hallmark of HF is a transition towards a foetal genotype which correlates with loss of cardiac functions. Thus, we wanted to investigate whether the foetal and neonatal cardiac ventricle displays serotonin responsiveness. Wistar rat hearts were collected day 3 and 1 before expected birth (days -3 and -1), as well as day 1, 3, 5 and 113 (age matched with Sham and HF) after birth. Hearts from post-infarction HF and sham-operated animals (Sham) were also collected. Heart tissue was examined for mRNA expression of 5-HT4, 5-HT2A and 5-HT2B serotonin receptors, 5-HT transporter, atrial natriuretic peptide (ANP) and myosin heavy chain (MHC)-α and MHC-β (real-time quantitative RT-PCR) as well as 5-HT-receptor-mediated increase in contractile function exvivo (electrical field stimulation of ventricular strips from foetal and neonatal rats and left ventricular papillary muscle from adult rats in organ bath). Both 5-HT4 mRNA expression and functional responses were highest at day -3 and decreased gradually to day 5, with a further decrease to adult levels. In HF, receptor mRNA levels and functional responses reappeared, but to lower levels than in the foetal ventricle. The 5-HT2A and 5-HT2B receptor mRNA levels increased to a maximum immediately after birth, but of these, only the 5-HT2A receptor mediated a positive inotropic response. We suggest that the 5-HT4 receptor is a representative of a foetal cardiac gene program, functional in late foetal development and reactivated in heart failure.
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18
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Cero FT, Hillestad V, Løberg EM, Christensen G, Larsen KO, Skjønsberg OH. IL-18 and IL-12 synergy induces matrix degrading enzymes in the lung. Exp Lung Res 2012; 38:406-19. [DOI: 10.3109/01902148.2012.716903] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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19
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Oh JG, Jeong D, Cha H, Kim JM, Lifirsu E, Kim J, Yang DK, Park CS, Kho C, Park S, Yoo YJ, Kim DH, Kim J, Hajjar RJ, Park WJ. PICOT increases cardiac contractility by inhibiting PKCζ activity. J Mol Cell Cardiol 2012; 53:53-63. [DOI: 10.1016/j.yjmcc.2012.03.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 03/06/2012] [Accepted: 03/09/2012] [Indexed: 11/28/2022]
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20
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Kotlo K, Johnson KR, Grillon JM, Geenen DL, deTombe P, Danziger RS. Phosphoprotein abundance changes in hypertensive cardiac remodeling. J Proteomics 2012; 77:1-13. [PMID: 22659219 DOI: 10.1016/j.jprot.2012.05.041] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/02/2012] [Accepted: 05/24/2012] [Indexed: 01/21/2023]
Abstract
There is over-whelming evidence that protein phosphorylations regulate cardiac function and remodeling. A wide variety of protein kinases, e.g., phosphoinositide 3-kinase (PI3K), Akt, GSK-3, TGFβ, and PKA, MAPKs, PKC, Erks, and Jaks, as well as phosphatases, e.g., phosphatase I (PP1) and calcineurin, control cardiomyocyte growth and contractility. In the present work, we used global phosphoprotein profiling to identify phosphorylated proteins associated with pressure overload (PO) cardiac hypertrophy and heart failure. Phosphoproteins from hypertrophic and systolic failing hearts from male hypertensive Dahl salt-sensitive rats, trans-aortic banded (TAC), and spontaneously hypertensive heart failure (SHHF) rats were analyzed. Profiling was performed by 2-dimensional difference in gel electrophoresis (2D-DIGE) on phospho-enriched proteins. A total of 25 common phosphoproteins with differences in abundance in (1) the 3 hypertrophic and/or (2) the 2 systolic failure heart models were identified (CI>99%) by matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) and Mascot analysis. Among these were (1) myofilament proteins, including alpha-tropomyosin and myosin regulatory light chain 2, cap Z interacting protein (cap ZIP), and tubulin β5; (2) mitochondrial proteins, including pyruvate dehydrogenase α, branch chain ketoacid dehydrogenase E1, and mitochondrial creatine kinase; (3) phosphatases, including protein phosphatase 2A and protein phosphatase 1 regulatory subunit; and (4) other proteins including proteosome subunits α type 3 and β type 7, and eukaryotic translation initiation factor 1A (eIF1A). The results include previously described and novel phosphoproteins in cardiac hypertrophy and systolic failure.
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Affiliation(s)
- Kumar Kotlo
- Department of Medicine, University of Illinois at Chicago, 840 South Wood Street, Chicago, IL 60612, USA
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21
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Protein phosphatase 2A affects myofilament contractility in non-failing but not in failing human myocardium. J Muscle Res Cell Motil 2011; 32:221-33. [PMID: 21959857 PMCID: PMC3205269 DOI: 10.1007/s10974-011-9261-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 09/09/2011] [Indexed: 02/04/2023]
Abstract
Protein phosphatase (PP) type 2A is a multifunctional serine/threonine phosphatase that is involved in cardiac excitation-contraction coupling. The PP2A core enzyme is a dimer, consisting of a catalytic C and a scaffolding A subunit, which is targeted to several cardiac proteins by a regulatory B subunit. At present, it is controversial whether PP2A and its subunits play a critical role in end-stage human heart failure. Here we report that the application of purified PP2AC significantly increased the Ca2+-sensitivity (ΔpCa50=0.05±0.01) of the contractile apparatus in isolated skinned myocytes of non-failing (NF) hearts. A higher phosphorylation of troponin I (cTnI) was found at protein kinase A sites (Ser23/24) in NF compared to failing myocardium. The basal Ca2+-responsiveness of myofilaments was enhanced in myocytes of ischemic (ICM, ΔpCa50=0.10±0.03) and dilated (DCM, ΔpCa50=0.06±0.04) cardiomyopathy compared to NF. However, in contrast to NF myocytes the treatment with PP2AC did not shift force-pCa relationships in failing myocytes. The higher basal Ca2+-sensitivity in failing myocytes coincided with a reduced protein expression of PP2AC in left ventricular tissue from patients suffering from ICM and DCM (by 50 and 56% compared to NF, respectively). However, PP2A activity was unchanged in failing hearts despite an increase of both total PP and PP1 activity. The expression of PP2AB56α was also decreased by 51 and 62% in ICM and DCM compared to NF, respectively. The phosphorylation of cTnI at Ser23/24 was reduced by 66 and 49% in ICM and DCM compared to NF hearts, respectively. Our results demonstrate that PP2A increases myofilament Ca2+-sensitivity in NF human hearts, most likely via cTnI dephosphorylation. This effect is not present in failing hearts, probably due to the lower baseline cTnI phosphorylation in failing compared to non-failing hearts.
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22
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Larsen KO, Yndestad A, Sjaastad I, Løberg EM, Goverud IL, Halvorsen B, Jia J, Andreassen AK, Husberg C, Jonasson S, Lipp M, Christensen G, Aukrust P, Skjønsberg OH. Lack of CCR7 induces pulmonary hypertension involving perivascular leukocyte infiltration and inflammation. Am J Physiol Lung Cell Mol Physiol 2011; 301:L50-9. [PMID: 21498626 DOI: 10.1152/ajplung.00048.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The chemokine receptor CCR7 regulates lymphocyte trafficking, and CCR7 deficiency induces infiltration of T and B cells adjacent to vessels in mouse lungs. Perivascular infiltration of T and B cells has also been found in human pulmonary arterial hypertension, and downregulation of the CCR7 receptor in circulating leukocytes of such patients has been observed. To investigate whether changes in the CCR7 system contribute to the pathogenesis of pulmonary hypertension, we utilized mice deficient of the CCR7 receptor. The cardiopulmonary and inflammatory responses of CCR7 depletion were evaluated in CCR7-deficient and wild-type mice. Measurements of cytokines upregulated in the animal model were also performed in patients with pulmonary hypertension and controls and in vascular smooth muscle cells. We found that mice lacking CCR7 had increased right ventricular systolic pressure, reduced pulmonary artery acceleration time, increased right ventricular/tibial length ratio, Rho kinase-mediated pulmonary vasoconstriction, and increased muscularization of distal arteries, indicating pulmonary hypertension. These mice also showed increased perivascular infiltration of leukocytes, consisting mainly of T and B cells, and increased mRNA levels of the inflammatory cytokines interleukin-12 and CX3CL1 within pulmonary tissue. Increased serum levels of interleukin-12 and CX3CL1 were also observed in patients with pulmonary hypertension, particularly in those with pulmonary hypertension associated with connective tissue disorder. In smooth muscle cells, interleukin-12 induced secretion of the angiogenic cytokine interleukin-8. We conclude that these results suggest a role for CCR7 in the development of pulmonary arterial hypertension, at least in some subgroups, possibly via pulmonary infiltration of lymphocytes and secretion of interleukin-12 and CX3CL1.
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Affiliation(s)
- Karl-Otto Larsen
- Department of Pulmonary Medicine, Oslo University Hospital Ullevål, Oslo, Norway.
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Lunde IG, Kvaløy H, Austbø B, Christensen G, Carlson CR. Angiotensin II and norepinephrine activate specific calcineurin-dependent NFAT transcription factor isoforms in cardiomyocytes. J Appl Physiol (1985) 2011; 111:1278-89. [PMID: 21474694 DOI: 10.1152/japplphysiol.01383.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Norepinephrine (NE) and angiotensin II (ANG II) are primary effectors of the sympathetic adrenergic and the renin-angiotensin-aldosterone systems, mediating hypertrophic, apoptotic, and fibrotic events in the myocardium. As NE and ANG II have been shown to affect intracellular calcium in cardiomyocytes, we hypothesized that they activate the calcium-sensitive, prohypertrophic calcineurin-nuclear factor of activated T-cell (NFATc) signaling pathway. More specifically, we have investigated isoform-specific activation of NFAT in NE- and ANG II-stimulated cardiomyocytes, as it is likely that each of the four calcineurin-dependent isoforms, c1-c4, play specific roles. We have stimulated neonatal ventriculocytes from C57/B6 and NFAT-luciferase reporter mice with ANG II or NE and quantified NFAT activity by luciferase activity and phospho-immunoblotting. ANG II and NE increased calcineurin-dependent NFAT activity 2.4- and 1.9-fold, measured as luciferase activity after 24 h of stimulation, and induced protein synthesis, measured by radioactive leucine incorporation after 24 and 72 h. To optimize measurements of NFAT isoforms, we examined the specificity of NFAT antibodies on peptide arrays and by immunoblotting with designed blocking peptides. Western analyses showed that both effectors activate NFATc1 and c4, while NFATc2 activity was regulated by NE only, as measured by phospho-NFAT levels. Neither ANG II nor NE activated NFATc3. As today's main therapies for heart failure aim at antagonizing the adrenergic and renin-angiotensin-aldosterone systems, understanding their intracellular actions is of importance, and our data, through validating a method for measuring myocardial NFATs, indicate that ANG II and NE activate specific NFATc isoforms in cardiomyocytes.
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Affiliation(s)
- Ida G Lunde
- Institute for Experimental Medical Research, Oslo Univ. Hospital-Ullevaal, Bldg. 7, 4 floor, Kirkeveien 166, 0407 Oslo, Norway.
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Caraballo JC, Yshii C, Butti ML, Westphal W, Borcherding JA, Allamargot C, Comellas AP. Hypoxia increases transepithelial electrical conductance and reduces occludin at the plasma membrane in alveolar epithelial cells via PKC-ζ and PP2A pathway. Am J Physiol Lung Cell Mol Physiol 2011; 300:L569-78. [PMID: 21257729 DOI: 10.1152/ajplung.00109.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
During pulmonary edema, the alveolar space is exposed to a hypoxic environment. The integrity of the alveolar epithelial barrier is required for the reabsorption of alveolar fluid. Tight junctions (TJ) maintain the integrity of this barrier. We set out to determine whether hypoxia creates a dysfunctional alveolar epithelial barrier, evidenced by an increase in transepithelial electrical conductance (G(t)), due to a decrease in the abundance of TJ proteins at the plasma membrane. Alveolar epithelial cells (AEC) exposed to mild hypoxia (Po(2) = 50 mmHg) for 30 and 60 min decreased occludin abundance at the plasma membrane and significantly increased G(t). Other cell adhesion molecules such as E-cadherin and claudins were not affected by hypoxia. AEC exposed to hypoxia increased superoxide, but not hydrogen peroxide (H(2)O(2)). Overexpression of superoxide dismutase 1 (SOD1) but not SOD2 prevented the hypoxia-induced G(t) increase and occludin reduction in AEC. Also, overexpression of catalase had a similar effect as SOD1, despite not detecting any increase in H(2)O(2) during hypoxia. Blocking PKC-ζ and protein phosphatase 2A (PP2A) prevented the hypoxia-induced occludin reduction at the plasma membrane and increase in G(t). In summary, we show that superoxide, PKC-ζ, and PP2A are involved in the hypoxia-induced increase in G(t) and occludin reduction at the plasma membrane in AEC.
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Affiliation(s)
- Juan Carlos Caraballo
- University of Iowa, Internal Medicine Department, Division of Pulmonary, Critical Care and Occupation Medicine, Iowa City, Iowa 52242, USA
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Cetinkaya M, Bostan O, Köksal N, Semizel E, Ozkan H, Cakır S. Early left ventricular diastolic dysfunction in premature infants born to preeclamptic mothers. J Perinat Med 2011; 39:89-95. [PMID: 21142411 DOI: 10.1515/jpm.2010.126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AIM To evaluate the cardiac function in premature infants born to preeclamptic mothers and its clinical consequences. METHODS This was a prospective observational cohort study performed in a tertiary neonatal intensive care unit. Fifty-three premature infants born to preeclamptic mothers comprising the study group were evaluated and compared with 42 premature infants born to normotensive mothers (control group). Relationship between echocardiographic measures and neonatal morbidity were assessed as the main outcome measures. RESULTS Left ventricle end-diastolic dimension (LVEDD), peak flow velocities during early diastole (peak E wave), peak flow velocities during atrial contraction (peak A wave), and peak E/A ratio were significantly lower in the study group. Within the study group, these parameters were also significantly lower in infants with respiratory problems. LVEDD was significantly smaller in preeclamptic infants with intrauterine growth retardation (IUGR). CONCLUSION Left ventricle diastolic dysfunction (LVDD) was detected in premature infants born to preeclamptic mothers in the first week after delivery. LVDD was associated with higher incidence of respiratory problems, transient tachypnea of the newborn, longer duration of oxygen requirement, and IUGR.
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Affiliation(s)
- Merih Cetinkaya
- Faculty of Medicine, Division of Neonatology, Department of Pediatrics, Uludag University, Bursa, Turkey.
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