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Shaydakov ME, Diaz JA, Eklöf B, Lurie F. Venous valve hypoxia as a possible mechanism of deep vein thrombosis: a scoping review. INT ANGIOL 2024; 43:309-322. [PMID: 38864688 DOI: 10.23736/s0392-9590.24.05170-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
INTRODUCTION The pathogenesis of deep vein thrombosis (DVT) has been explained by an interplay between a changed blood composition, vein wall alteration, and blood flow abnormalities. A comprehensive investigation of these components of DVT pathogenesis has substantially promoted our understanding of thrombogenesis in the venous system. Meanwhile, the process of DVT initiation remains obscure. This systematic review aims to collect, analyze, and synthesize the published evidence to propose hypoxia as a possible trigger of DVT. EVIDENCE ACQUISITION An exhaustive literature search was conducted across multiple electronic databased including PubMed, EMBASE, Scopus, and Web of Science to identify studies pertinent to the research hypothesis. The search was aimed at exploring the connection between hypoxia, reoxygenation, and the initiation of deep vein thrombosis (DVT). The following key words were used: "deep vein thrombosis," "venous thrombosis," "venous thromboembolism," "hypoxia," "reoxygenation," "venous valve," and "venous endothelium." Reviews, case reports, editorials, and letters were excluded. EVIDENCE SYNTHESIS Based on the systematic search outcome, 156 original papers relevant to the issue were selected for detailed review. These studies encompassed a range of experimental and observational clinical research, focusing on various aspects of DVT, including the anatomical, physiological, and cellular bases of the disease. A number of studies suggested limitations in the traditional understanding of Virchow's triad as an acceptable explanation for DVT initiation. Emerging evidence points to more complex interactions and additional factors that may be critical in the early stages of thrombogenesis. The role of venous valves has been recognized but remains underappreciated, with several studies indicating that these sites may act as primary loci for thrombus formation. A collection of studies describes the effects of hypoxia on venous endothelial cells at the cellular and molecular levels. Hypoxia influences several pathways that regulate endothelial cell permeability, inflammatory response, and procoagulation activity, underpinning the endothelial dysfunction noted in DVT. CONCLUSIONS Hypoxia of the venous valve may serve as an independent hypothesis to outline the DVT triggering process. Further research projects in this field may discover new molecular pathways responsible for the disease and suggest new therapeutic targets.
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Affiliation(s)
- Maxim E Shaydakov
- Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburg, PA, USA -
| | - Jose A Diaz
- Division of Surgical Research, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Fedor Lurie
- Jobst Vascular Institute, ProMedica Health System, Toledo, OH, USA
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Oliveira RHDM, Annex BH, Popel AS. Endothelial cells signaling and patterning under hypoxia: a mechanistic integrative computational model including the Notch-Dll4 pathway. Front Physiol 2024; 15:1351753. [PMID: 38455844 PMCID: PMC10917925 DOI: 10.3389/fphys.2024.1351753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/12/2024] [Indexed: 03/09/2024] Open
Abstract
Introduction: Several signaling pathways are activated during hypoxia to promote angiogenesis, leading to endothelial cell patterning, interaction, and downstream signaling. Understanding the mechanistic signaling differences between endothelial cells under normoxia and hypoxia and their response to different stimuli can guide therapies to modulate angiogenesis. We present a novel mechanistic model of interacting endothelial cells, including the main pathways involved in angiogenesis. Methods: We calibrate and fit the model parameters based on well-established modeling techniques that include structural and practical parameter identifiability, uncertainty quantification, and global sensitivity. Results: Our results indicate that the main pathways involved in patterning tip and stalk endothelial cells under hypoxia differ, and the time under hypoxia interferes with how different stimuli affect patterning. Additionally, our simulations indicate that Notch signaling might regulate vascular permeability and establish different Nitric Oxide release patterns for tip/stalk cells. Following simulations with various stimuli, our model suggests that factors such as time under hypoxia and oxygen availability must be considered for EC pattern control. Discussion: This project provides insights into the signaling and patterning of endothelial cells under various oxygen levels and stimulation by VEGFA and is our first integrative approach toward achieving EC control as a method for improving angiogenesis. Overall, our model provides a computational framework that can be built on to test angiogenesis-related therapies by modulation of different pathways, such as the Notch pathway.
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Affiliation(s)
| | - Brian H. Annex
- Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Aleksander S. Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
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Jung U, Kim M, Dowker-Key P, Noë S, Bettaieb A, Shepherd E, Voy B. Hypoxia promotes proliferation and inhibits myogenesis in broiler satellite cells. Poult Sci 2024; 103:103203. [PMID: 37980759 PMCID: PMC10685027 DOI: 10.1016/j.psj.2023.103203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/07/2023] [Accepted: 10/12/2023] [Indexed: 11/21/2023] Open
Abstract
Breast muscle myopathies in broilers compromise meat quality and continue to plague the poultry industry. Broiler breast muscle myopathies are characterized by impaired satellite cell (SC)-mediated repair, and localized tissue hypoxia and dysregulation of oxygen homeostasis have been implicated as contributing factors. The present study was designed to test the hypothesis that hypoxia disrupts the ability of SC to differentiate and form myotubes, both of which are key components of myofiber repair, and to determine the extent to which effects are reversed by restoration of oxygen tension. Primary SC were isolated from pectoralis major of young (5 d) Cobb 700 chicks and maintained in growth conditions or induced to differentiate under normoxic (20% O2) or hypoxic (1% O2) conditions for up to 48 h. Hypoxia enhanced SC proliferation while inhibiting myogenic potential, with decreased fusion index and suppressed myotube formation. Reoxygenation after hypoxia partially reversed effects on both proliferation and myogenesis. Western blotting showed that hypoxia diminished myogenin expression, activated AMPK, upregulated proliferation markers, and increased molecular signaling of cellular stress. Hypoxia also promoted accumulation of lipid droplets in myotubes. Targeted RNAseq identified numerous differentially expressed genes across differentiation under hypoxia, including several genes that have been associated with myopathies in vivo. Altogether, these data demonstrate localized hypoxia may influence SC behavior in ways that disrupt muscle repair and promote the formation of myopathies in broilers.
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Affiliation(s)
- Usuk Jung
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA
| | - Minjeong Kim
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA
| | - Presley Dowker-Key
- Department of Nutrition, The University of Tennessee, Knoxville, TN 37996, USA
| | - Simon Noë
- Research Group for Neurorehabilitation (eNRGy), Department of Rehabilitation Sciences, KU Leuven, 3001 Leuven, Belgium
| | - Ahmed Bettaieb
- Department of Nutrition, The University of Tennessee, Knoxville, TN 37996, USA
| | - Elizabeth Shepherd
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA
| | - Brynn Voy
- Department of Animal Science, The University of Tennessee, Knoxville, TN 37996, USA.
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Felipe Souza E Silva L, Siena Dos Santos A, Mayumi Yuzawa J, Luiz de Barros Torresi J, Ziroldo A, Rosado Rosenstock T. SIRTUINS MODULATORS COUNTERACT MITOCHONDRIAL DYSFUNCTION IN CELLULAR MODELS OF HYPOXIA: RELEVANCE TO SCHIZOPHRENIA. Neuroscience 2023:S0306-4522(23)00200-2. [PMID: 37169164 DOI: 10.1016/j.neuroscience.2023.04.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 04/16/2023] [Accepted: 04/27/2023] [Indexed: 05/13/2023]
Abstract
Schizophrenia (SZ) is a neurodevelopmental-associated disorder strongly related to environmental factors, such as hypoxia. Because there is no cure for SZ or any pharmacological approach that could revert hypoxia-induced cellular damages, we evaluated whether modulators of sirtuins could abrogate hypoxia-induced mitochondrial deregulation as a neuroprotective strategy. Firstly, astrocytes from control (Wistar) and Spontaneously Hypertensive Rats (SHR), a model of both SZ and neonatal hypoxia, were submitted to chemical hypoxia. Then, cells were exposed to different concentrations of Nicotinamide (NAM), Resveratrol (Resv), and Sirtinol (Sir) for 48hrs. Our data indicate that sirtuins modulation reduces cell death increasing the acetylation of histone 3. This outcome is related to the rescue of loss of mitochondrial membrane potential, changes in mitochondrial calcium buffering capacity, decreased O2-• levels and increased expression of metabolic regulators (Nrf-1 and Nfe2l2) and mitochondrial content. Such findings are relevant not only for hypoxia-associated conditions, named pre-eclampsia but also for SZ since prenatal hypoxia is a relevant environmental factor related to this burdensome neuropsychiatric disorder.
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Affiliation(s)
- Luiz Felipe Souza E Silva
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Amanda Siena Dos Santos
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Jessica Mayumi Yuzawa
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Science, São Paulo, Brazil
| | | | - Alan Ziroldo
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Science, São Paulo, Brazil
| | - Tatiana Rosado Rosenstock
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil; Dept. of Bioscience, In-vitro Neuroscience, Sygnature Discovery, Nottingham, United Kingdom.
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Oliveira RHM, Annex BH, Popel AS. Endothelial cells signaling and patterning under hypoxia: a mechanistic integrative computational model including the Notch-Dll4 pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.03.539270. [PMID: 37205581 PMCID: PMC10187169 DOI: 10.1101/2023.05.03.539270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Several signaling pathways are activated during hypoxia to promote angiogenesis, leading to endothelial cell patterning, interaction, and downstream signaling. Understanding the mechanistic signaling differences between normoxia and hypoxia can guide therapies to modulate angiogenesis. We present a novel mechanistic model of interacting endothelial cells, including the main pathways involved in angiogenesis. We calibrate and fit the model parameters based on well-established modeling techniques. Our results indicate that the main pathways involved in the patterning of tip and stalk endothelial cells under hypoxia differ, and the time under hypoxia affects how a reaction affects patterning. Interestingly, the interaction of receptors with Neuropilin1 is also relevant for cell patterning. Our simulations under different oxygen concentrations indicate time- and oxygen-availability-dependent responses for the two cells. Following simulations with various stimuli, our model suggests that factors such as period under hypoxia and oxygen availability must be considered for pattern control. This project provides insights into the signaling and patterning of endothelial cells under hypoxia, contributing to studies in the field.
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Affiliation(s)
- Rebeca Hannah M Oliveira
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205, USA
| | - Brian H Annex
- Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, Maryland, 21205, USA
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Osuru HP, Lavallee M, Thiele RH. Molecular and Cellular Response of the Myocardium (H9C2 Cells) Towards Hypoxia and HIF-1α Inhibition. Front Cardiovasc Med 2022; 9:711421. [PMID: 35928940 PMCID: PMC9343679 DOI: 10.3389/fcvm.2022.711421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/21/2022] [Indexed: 11/30/2022] Open
Abstract
Introduction Oxidative phosphorylation is an essential feature of Animalian life. Multiple adaptations have developed to protect against hypoxia, including hypoxia-inducible-factors (HIFs). The major role of HIFs may be in protecting against oxidative stress, not the preservation of high-energy phosphates. The precise mechanism(s) of HIF protection is not completely understood. Materials and Methods To better understand the role of hypoxia-inducible-factor-1, we exposed heart/myocardium cells (H9c2) to both normoxia and hypoxia, as well as cobalt chloride (prolyl hydroxylase inhibitor), echniomycin (HIF inhibitor), A2P (anti-oxidant), and small interfering RNA to beclin-1. We measured cell viability, intracellular calcium and adenosine triphosphate, NADP/NADPH ratios, total intracellular reactive oxidative species levels, and markers of oxidative and antioxidant levels measured. Results Hypoxia (1%) leads to increased intracellular Ca2+ levels, and this response was inhibited by A2P and echinomycin (ECM). Exposure of H9c2 cells to hypoxia also led to an increase in both mRNA and protein expression for Cav 1.2 and Cav 1.3. Exposure of H9c2 cells to hypoxia led to a decrease in intracellular ATP levels and a sharp reduction in total ROS, SOD, and CAT levels. The impact of hypoxia on ROS was reversed with HIF-1 inhibition through ECM. Exposure of H9c2 cells to hypoxia led to an increase in Hif1a, VEGF and EPO protein expression, as well as a decrease in mitochondrial DNA. Both A2P and ECM attenuated this response to varying degrees. Conclusion Hypoxia leads to increased intracellular Ca2+, and inhibition of HIF-1 attenuates the increase in intracellular Ca2+ that occurs with hypoxia. HIF-1 expression leads to decreased adenosine triphosphate levels, but the role of HIF-1 on the production of reactive oxidative species remains uncertain. Anti-oxidants decrease HIF-1 expression in the setting of hypoxia and attenuate the increase in Ca2+ that occurs during hypoxia (with no effect during normoxia). Beclin-1 appears to drive autophagy in the setting of hypoxia (through ATG5) but not in normoxia. Additionally, Beclin-1 is a powerful driver of reactive oxidative species production and plays a role in ATP production. HIF-1 inhibition does not affect autophagy in the setting of hypoxia, suggesting that there are other drivers of autophagy that impact beclin-1.
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Subasinghe SAAS, Pautler RG, Samee MAH, Yustein JT, Allen MJ. Dual-Mode Tumor Imaging Using Probes That Are Responsive to Hypoxia-Induced Pathological Conditions. BIOSENSORS 2022; 12:478. [PMID: 35884281 PMCID: PMC9313010 DOI: 10.3390/bios12070478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/22/2022] [Accepted: 06/26/2022] [Indexed: 05/02/2023]
Abstract
Hypoxia in solid tumors is associated with poor prognosis, increased aggressiveness, and strong resistance to therapeutics, making accurate monitoring of hypoxia important. Several imaging modalities have been used to study hypoxia, but each modality has inherent limitations. The use of a second modality can compensate for the limitations and validate the results of any single imaging modality. In this review, we describe dual-mode imaging systems for the detection of hypoxia that have been reported since the start of the 21st century. First, we provide a brief overview of the hallmarks of hypoxia used for imaging and the imaging modalities used to detect hypoxia, including optical imaging, ultrasound imaging, photoacoustic imaging, single-photon emission tomography, X-ray computed tomography, positron emission tomography, Cerenkov radiation energy transfer imaging, magnetic resonance imaging, electron paramagnetic resonance imaging, magnetic particle imaging, and surface-enhanced Raman spectroscopy, and mass spectrometric imaging. These overviews are followed by examples of hypoxia-relevant imaging using a mixture of probes for complementary single-mode imaging techniques. Then, we describe dual-mode molecular switches that are responsive in multiple imaging modalities to at least one hypoxia-induced pathological change. Finally, we offer future perspectives toward dual-mode imaging of hypoxia and hypoxia-induced pathophysiological changes in tumor microenvironments.
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Affiliation(s)
| | - Robia G. Pautler
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA; (R.G.P.); (M.A.H.S.)
| | - Md. Abul Hassan Samee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA; (R.G.P.); (M.A.H.S.)
| | - Jason T. Yustein
- Integrative Molecular and Biomedical Sciences and the Department of Pediatrics in the Texas Children’s Cancer and Hematology Centers and The Faris D. Virani Ewing Sarcoma Center, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Matthew J. Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA;
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Leyden C, Brüggemann T, Debinski F, Simacek CA, Dehmelt FA, Arrenberg AB. Efficacy of Tricaine (MS-222) and Hypothermia as Anesthetic Agents for Blocking Sensorimotor Responses in Larval Zebrafish. Front Vet Sci 2022; 9:864573. [PMID: 35419446 PMCID: PMC8996001 DOI: 10.3389/fvets.2022.864573] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 02/28/2022] [Indexed: 12/12/2022] Open
Abstract
Tricaine, or MS-222, is the most commonly used chemical anesthetic in zebrafish research. It is thought to act via blocking voltage-gated sodium channels, though its mechanism of action, particularly at the neuronal level, is not yet fully understood. Here, we first characterized the effects of tricaine on both body balance and touch responses in freely swimming animals, before determining its effect on the neural activity underlying the optokinetic response at the level of motion perception, sensorimotor signaling and the generation of behavior in immobilized animals. We found that the standard dose for larvae (168 mg/L) induced loss of righting reflex within 30 seconds, which then recovered within 3 minutes. Optokinetic behavior recovered within 15 minutes. Calcium imaging showed that tricaine interferes with optokinetic behavior by interruption of the signals between the pretectum and hindbrain. The motion sensitivity indices of identified sensory neurons were unchanged in larvae exposed to tricaine, though fewer such neurons were detected, leaving a small population of active sensory neurons. We then compared tricaine with gradual cooling, a potential non-chemical alternative method of anesthesia. While neuronal tuning appeared to be affected in a similar manner during gradual cooling, gradual cooling induced a surge in calcium levels in both the pretectum and hindbrain. This calcium surge, alongside a drop in heartrate, is potentially associated with harmful changes in physiology and suggests that tricaine is a better anesthetic agent than gradual cooling for zebrafish laboratory research.
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Affiliation(s)
- Claire Leyden
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany.,Graduate Training Centre of Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Timo Brüggemann
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Florentyna Debinski
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Clara A Simacek
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Florian A Dehmelt
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
| | - Aristides B Arrenberg
- Werner Reichardt Centre for Integrative Neuroscience and Institute for Neurobiology, University of Tuebingen, Tuebingen, Germany
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Chrysant SG, Chrysant GS. Beneficial cardiovascular and remodeling effects of SGLT2 inhibitors: pathophysiologic mechanisms. Expert Rev Cardiovasc Ther 2022; 20:223-232. [PMID: 35320057 DOI: 10.1080/14779072.2022.2057949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION The intent of this paper is to review the data regarding the multipotential effects of the sodium-glucose cotransporter 2 (SGLT 2) inhibitors, their cardiovascular protective effects, and their mechanism of action. AREAS COVERED The SGLT2 inhibitors exert their beneficial antidiabetic and cardioprotective effects through increased glucose excretion from the kidneys, blood pressure and weight lowering, vasodilation and other potential beneficial effects. They have been used for the treatment of patients with type 2 diabetes mellitus (T2DM) as well as in patients with cardiovascular disease (CVD), coronary artery disease (CAD),and heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). In order to get a better understanding of their mechanism of action for their multiple cardiovascular protective effects, a Medline search of the English language literature was conducted between 2015 and February 2022 and 46 pertinent papers were selected. EXPERT OPINION The analysis of data clearly demonstrated that the use of the SGLT2 inhibitors besides their antidiabetic effects, provide additional protection against CVD, CAD, and HFrEF and HFpEF, and death, but not stroke, in both diabetic and non-diabetic patients. Therefore, they should be preferably used for the treatment of patients with T2DM with preexisting CVD, CAD, and HFrEF and HFpEF.
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Affiliation(s)
- Steven G Chrysant
- Department of Cardiology, University of Oklahoma Health Sciences Center, Oklahoma City, USA
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Pecher SJ, Potthast AB, von Versen-Höynck F, Das AM. Impact of Short-Term Hypoxia on Sirtuins as Regulatory Elements in HUVECs. J Clin Med 2020; 9:jcm9082604. [PMID: 32796661 PMCID: PMC7464651 DOI: 10.3390/jcm9082604] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 12/11/2022] Open
Abstract
Background: Sirtuins (SIRT) are NAD+-dependent deacetylases that are involved in stress response, antioxidative defense, and longevity via posttranslational modifications. SIRT1 directly activates nitric oxide synthase (NOS). Aging is associated with a reduced sirtuin function and reduction of the cofactor NAD+. Age-related atherosclerosis and vascular diseases are linked to a compromised sirtuin function. Vascular events like stroke and cardiac infarction result in acute hypoxia, which can additionally impact sirtuins and thus the vascular function. This prompted us to study sirtuins in intact HUVECs, under acute, short-term hypoxic conditions. Methods: We measured intracellular sirtuin and NAD+ levels in HUVECs exposed to hypoxia (2% O₂) for 10–120 min, compared to normoxic controls. SIRT1, SIRT3, and SIRT4 were measured at the protein (Western Blot) and the transcript level (qRT-PCR), SIRT1 and SIRT3 at the enzyme level (fluorometrically), and NAD+ levels were measured spectrophotometrically. Results: We observed a reduction of SIRT1 and SIRT4 at the protein level, a downregulation of SIRT1 at the transcript level and increased NAD+ levels under hypoxia. SIRT3 was not affected by hypoxia. Conclusions: Downregulation of SIRT1 under hypoxia might reduce production of the reactive oxygen species (ROS) via the respiratory chain and inhibit the mitochondrial ATP-synthase, resulting in energy conservation. NOS might be impaired if SIRT1 is decreased. Increased NAD+ levels might compensate these effects. Hypoxic downregulation of SIRT4 might lead to mitochondrial uncoupling, hence endothelial dysfunction, and ADP/ATP-translocase 2 (ANT2)-inhibition. NAD+ upregulation might partly compensate this effect.
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Affiliation(s)
- Simone Johanna Pecher
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (S.J.P.); (A.B.P.)
| | - Arne Björn Potthast
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (S.J.P.); (A.B.P.)
| | - Frauke von Versen-Höynck
- Department of Obstetrics and Gynecology, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany;
| | - Anibh Martin Das
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School (MHH), Carl-Neuberg-Straße 1, 30625 Hannover, Germany; (S.J.P.); (A.B.P.)
- Correspondence: ; Tel.: +49-511-532-3220
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Allen KN, Vázquez-Medina JP. Natural Tolerance to Ischemia and Hypoxemia in Diving Mammals: A Review. Front Physiol 2019; 10:1199. [PMID: 31620019 PMCID: PMC6763568 DOI: 10.3389/fphys.2019.01199] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 09/03/2019] [Indexed: 12/15/2022] Open
Abstract
Reperfusion injury follows ischemia/reperfusion events occurring during myocardial infarction, stroke, embolism, and other peripheral vascular diseases. Decreased blood flow and reduced oxygen tension during ischemic episodes activate cellular pathways that upregulate pro-inflammatory signaling and promote oxidant generation. Reperfusion after ischemia recruits inflammatory cells to the vascular wall, further exacerbating oxidant production and ultimately resulting in cell death, tissue injury, and organ dysfunction. Diving mammals tolerate repetitive episodes of peripheral ischemia/reperfusion as part of the cardiovascular adjustments supporting long duration dives. These adjustments allow marine mammals to optimize the use of their body oxygen stores while diving but can result in selectively reduced perfusion to peripheral tissues. Remarkably, diving mammals show no apparent detrimental effects associated with these ischemia/reperfusion events. Here, we review the current knowledge regarding the strategies marine mammals use to suppress inflammation and cope with oxidant generation potentially derived from diving-induced ischemia/reperfusion.
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Aiku AO, Marshall JM. Contribution of prostaglandins to exercise hyperaemia: workload, ethnicity and sex matter! J Physiol 2019; 597:4887-4900. [PMID: 31399992 DOI: 10.1113/jp278033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/06/2019] [Indexed: 01/03/2023] Open
Abstract
The contribution of prostaglandins (PGs) to exercise hyperaemia is controversial. In this review, we argue this is partly explained by differences in exercise intensity between studies. The effects of cyclooxygenase (COX) inhibition and PG assays indicate that PGs contribute more at moderate to heavy than at light workloads and are mainly released by low tissue O2 . But, the release and actions of PGs also depend on other O2 -dependent dilators including ATP, adenosine and NO. K+ may inhibit the action of PGs and other mediators by causing hyperpolarization, but contributes to the hyperaemia. Thus, at lighter loads, the influence of PGs may be blunted by K+ , while COX inhibition leads to compensatory increases in other O2 -dependent dilators. In addition, we show that other sources of variability are sex and ethnicity. Our findings indicate that exercise hyperaemia following rhythmic contractions at 60% maximum voluntary contraction, is smaller in young black African (BA) men and women than in their white European (WE) counterparts, but larger in men than in women of both ethnicities. We propose the larger absolute force in men causes greater vascular occlusion and accumulation of dilators, while blunted hyperaemia in BAs may reflect lower oxidative capacity and O2 requirement. Nevertheless, COX inhibition attenuated peak hyperaemia by ∼30% in WE, BA men and WE women, indicating PGs make a substantial contribution in all three groups. There was no effect in BA women. Lack of PG involvement may provide early evidence of endothelial dysfunction, consistent in BA women with their greater risk of cardiovascular disease.
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Affiliation(s)
- Abimbola O Aiku
- Institute of Clinical Sciences, College of Medical & Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Janice M Marshall
- Institute of Clinical Sciences, College of Medical & Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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Abstract
Diabetes is a global epidemic and a leading cause of death with more than 422 million patients worldwide out of whom around 392 million alone suffer from type 2 diabetes (T2D). Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are novel and effective drugs in managing glycemia of T2D patients. These inhibitors gained recent clinical and basic research attention due to their clinically observed cardiovascular protective effects. Although interest in the study of various SGLT isoforms and the effect of their inhibition on cardiovascular function extends over the past 20 years, an explanation of the effects observed clinically based on available experimental data is not forthcoming. The remarkable reduction in cardiovascular (CV) mortality (38%), major CV events (14%), hospitalization for heart failure (35%), and death from any cause (32%) observed over a period of 2.6 years in patients with T2D and high CV risk in the EMPA-REG OUTCOME trial involving the SGLT2 inhibitor empagliflozin (Empa) have raised the possibility that potential novel, more specific mechanisms of SGLT2 inhibition synergize with the known modest systemic improvements, such as glycemic, body weight, diuresis, and blood pressure control. Multiple studies investigated the direct impact of SGLT2i on the cardiovascular system with limited findings and the pathophysiological role of SGLTs in the heart. The direct impact of SGLT2i on cardiac homeostasis remains controversial, especially that SGLT1 isoform is the only form expressed in the capillaries and myocardium of human and rodent hearts. The direct impact of SGLT2i on the cardiovascular system along with potential lines of future research is summarized in this review.
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Zhang B, Paffett ML, Naik JS, Jernigan NL, Walker BR, Resta TC. Cholesterol Regulation of Pulmonary Endothelial Calcium Homeostasis. CURRENT TOPICS IN MEMBRANES 2018; 82:53-91. [PMID: 30360783 DOI: 10.1016/bs.ctm.2018.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cholesterol is a key structural component and regulator of lipid raft signaling platforms critical for cell function. Such regulation may involve changes in the biophysical properties of lipid microdomains or direct protein-sterol interactions that alter the function of ion channels, receptors, enzymes, and membrane structural proteins. Recent studies have implicated abnormal membrane cholesterol levels in mediating endothelial dysfunction that is characteristic of pulmonary hypertensive disorders, including that resulting from long-term exposure to hypoxia. Endothelial dysfunction in this setting is characterized by impaired pulmonary endothelial calcium entry and an associated imbalance that favors production vasoconstrictor and mitogenic factors that contribute to pulmonary hypertension. Here we review current knowledge of cholesterol regulation of pulmonary endothelial Ca2+ homeostasis, focusing on the role of membrane cholesterol in mediating agonist-induced Ca2+ entry and its components in the normal and hypertensive pulmonary circulation.
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Affiliation(s)
- Bojun Zhang
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Michael L Paffett
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Jay S Naik
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Benjimen R Walker
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States.
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15
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Song X, Yue Z, Zhang J, Jiang Y, Wang Z, Zhang S. Multicolor Upconversion Nanoprobes Based on a Dual Luminescence Resonance Energy Transfer Assay for Simultaneous Detection and Bioimaging of [Ca2+
]i
and pHi
in Living Cells. Chemistry 2018; 24:6458-6463. [DOI: 10.1002/chem.201800154] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Indexed: 12/24/2022]
Affiliation(s)
- Xinyue Song
- Shandong Provincial Key Laboratory of Detection Technology, for Tumour Markers; College of Chemistry and Chemical Engineering; Linyi University; Linyi 276005 P. R. China
| | - Zihong Yue
- Shandong Provincial Key Laboratory of Detection Technology, for Tumour Markers; College of Chemistry and Chemical Engineering; Linyi University; Linyi 276005 P. R. China
- Shandong Sino-Japanese Center for Collaborative Research, of Carbon Nanomaterials; College of Chemistry and Chemical Engineering; Qingdao University; Shandong 266071 P. R. China
| | - Jiayu Zhang
- Shandong Provincial Key Laboratory of Detection Technology, for Tumour Markers; College of Chemistry and Chemical Engineering; Linyi University; Linyi 276005 P. R. China
| | - Yanxialei Jiang
- Shandong Provincial Key Laboratory of Detection Technology, for Tumour Markers; College of Chemistry and Chemical Engineering; Linyi University; Linyi 276005 P. R. China
| | - Zonghua Wang
- Shandong Sino-Japanese Center for Collaborative Research, of Carbon Nanomaterials; College of Chemistry and Chemical Engineering; Qingdao University; Shandong 266071 P. R. China
| | - Shusheng Zhang
- Shandong Provincial Key Laboratory of Detection Technology, for Tumour Markers; College of Chemistry and Chemical Engineering; Linyi University; Linyi 276005 P. R. China
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16
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Pahima H, Reina S, Tadmor N, Dadon-Klein D, Shteinfer-Kuzmine A, Mazure NM, De Pinto V, Shoshan-Barmatz V. Hypoxic-induced truncation of voltage-dependent anion channel 1 is mediated by both asparagine endopeptidase and calpain 1 activities. Oncotarget 2018; 9:12825-12841. [PMID: 29560113 PMCID: PMC5849177 DOI: 10.18632/oncotarget.24377] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/25/2018] [Indexed: 01/04/2023] Open
Abstract
The voltage-dependent anion channel 1 (VDAC1), an outer mitochondria membrane (OMM)
protein, serves as a mitochondrial gatekeeper, mediating the transport of
nucleotides, Ca2+ and other metabolites across the OMM. VDAC1 also
plays a central role in mitochondria-mediated apoptosis by facilitating the release
of apoptotic proteins and by association with both pro- and anti-apoptotic proteins.
Tumor cells, which are constantly exposed to hypoxic conditions, affect the cell via
the transcription factor hypoxia-inducible factor (HIF) that induces transcriptional
activity. In cultured cells and in lung cancer patients, hypoxia induces VDAC1
truncation at the C-terminus (VDAC1-ΔC). However, the molecular mechanisms
involved in VDAC1-ΔC formation are unknown. Here, we show that hypoxia-induced
VDAC1-ΔC formation is inhibited by the Ca2+ chelator
BAPTA-AM, by calpain inhibitor-1, by inhibitor of the asparagine endopeptidase (AEP)
and by si-RNA targeting HIF1-α or Ca2+-activated protease
calpain-1 expression but not that of calpain-2. Finally, VDAC1-ΔC expressed in
bacteria and reconstituted into a planar lipid bilayer exhibited decreased channel
conductance relative to the full-length protein, yet retained voltage-dependent
conductance. These findings suggest that hypoxia, acting via HIF-1α
expression, leads to VDAC1 cleavage involving the activation of calpain 1 and
AEP.
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Affiliation(s)
- Hadas Pahima
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Simona Reina
- Department of Biomedicine and Biotechnology, University of Catania and National Institute for Biomembranes and Biosystems, Section of Catania, Catania 95125, Italy.,Department of Biological, Geological and Environmental Sciences, University of Catania, Catania 95125, Italy
| | - Noa Tadmor
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Daniella Dadon-Klein
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Anna Shteinfer-Kuzmine
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Nathalie M Mazure
- Institute for Research on Cancer and Aging of Nice, University of Nice Sophia-Antipolis, Centre Antoine Lacassagne, Nice 06189, France.,Present address: INSERM U1065, C3M, Nice 06204, France
| | - Vito De Pinto
- Department of Biomedicine and Biotechnology, University of Catania and National Institute for Biomembranes and Biosystems, Section of Catania, Catania 95125, Italy
| | - Varda Shoshan-Barmatz
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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17
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Keeley TP, Siow RCM, Jacob R, Mann GE. Reduced SERCA activity underlies dysregulation of Ca 2+ homeostasis under atmospheric O 2 levels. FASEB J 2017; 32:2531-2538. [PMID: 29273673 PMCID: PMC5901376 DOI: 10.1096/fj.201700685rrr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Unregulated increases in cellular Ca2+ homeostasis are a hallmark of pathophysiological conditions and a key trigger of cell death. Endothelial cells cultured under physiologic O2 conditions (5% O2) exhibit a reduced cytosolic Ca2+ response to stimulation. The mechanism for reduced plateau [Ca2+]i upon stimulation was due to increased sarco/endoplasmic reticulum Ca2+ ATPase (SERCA)-mediated reuptake rather than changes in Ca2+ influx capacity. Agonist-stimulated phosphorylation of the SERCA regulatory protein phospholamban was increased in cells cultured under 5% O2. Elevation of cytosolic and mitochondrial [Ca2+] and cell death after prolonged ionomycin treatment, as a model of Ca2+ overload, were lower when cells were cultured long-term under 5% compared with 18% O2. This protection was abolished by cotreatment with the SERCA inhibitor cyclopiazonic acid. Taken together, these results demonstrate that culturing cells under hyperoxic conditions reduces their ability to efficiently regulate [Ca2+]i, resulting in greater sensitivity to cytotoxic stimuli.-Keeley, T. P., Siow, R. C. M., Jacob, R., Mann, G. E. Reduced SERCA activity underlies dysregulation of Ca2+ homeostasis under atmospheric O2 levels.
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Affiliation(s)
- Thomas P Keeley
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Richard C M Siow
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Ron Jacob
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Giovanni E Mann
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
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18
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SethuNarayanan S. Role of the DBP Gene in the Regulation of Circadian and Cyclic Hematopoiesis: A Case for Potential Linkages. INT J HUM GENET 2017. [DOI: 10.1080/09723757.2011.11886136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- S.R. SethuNarayanan
- Inter-disciplinary Centre for Clinical Research (IZKF), University of Leipzig, Germany
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19
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Xin L, Zhang H, Du X, Li Y, Li M, Wang L, Wang H, Qiu L, Song L. The systematic regulation of oyster CgIL17-1 and CgIL17-5 in response to air exposure. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 63:144-155. [PMID: 27268575 DOI: 10.1016/j.dci.2016.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/31/2016] [Accepted: 06/02/2016] [Indexed: 06/06/2023]
Abstract
As a proinflammatory cytokine, vertebrate interleukin 17 (IL17) plays a vital role in the balance of inflammation and homeostasis, and is involved in a systemic regulation of glucose homeostasis. In the present study, a remarkable increase of glucose concentration was observed in oyster serum after 2 d air exposure, which was followed by a rapid up-regulation of CgIL17-1 and CgIL17-5. After oysters was received an injection of extra glucose, the mRNA expressions of CgIL17-1 and CgIL17-5 were also significantly up-regulated. The histopathological changes of hepatopancreas were observed after the oysters were treated by the recombinant proteins of CgIL17-1 and CgIL17-5 in vivo or subjected to air exposure. A significant decrease of GSK3β (Glycogen synthase kinase-3β) protein was also observed after the injection of CgIL17-1 and CgIL17-5 recombinant proteins in vivo. When the oysters with CgIL17-1 and CgIL17-5 genes knocked down were subjected to air exposure, the decline of GSK3β concentration was slowed down and it could still be obviously detected after 7 d compared with that in the control. Meanwhile, the expression of CgDefensin and CgDFFA was inhibited, while CgIAP was up-regulated when CgIL17-1 and CgIL17-5 genes were knocked down, and the oysters exhibited higher mortality (p < 0.05) at 3 d, whereas lower at the late stage of air exposure compared with that in the controls. The results collectively suggested that once oysters were exposed to air, the synthesis of proinflammatory cytokines CgIL17-1 and CgIL17-5 was induced by the up-regulated glucose concentration in oyster serum, which would be not only a negative feedback to the high glucose concentration through mediating the regulation of GSK3β, but also an inducer on tissue damage and immunocompetence as well as the adaptability to stresses.
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Affiliation(s)
- Lusheng Xin
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huan Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Xinyu Du
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yiqun Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meijia Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingling Wang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China
| | - Hao Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Limei Qiu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Linsheng Song
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian 116023, China.
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20
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The Ca2+/Mn2+-transporting SPCA2 pump is regulated by oxygen and cell density in colon cancer cells. Biochem J 2016; 473:2507-18. [PMID: 27316461 DOI: 10.1042/bcj20160477] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 06/17/2016] [Indexed: 12/18/2022]
Abstract
The mammalian SPCA1 and SPCA2 ATPases localize in membranes of the secretory pathway and transport ions of Ca(2+) and Mn(2+) The role of tissue-specific SPCA2 isoform, highly expressed in lungs, mammary gland and gastrointestinal tract, is poorly understood. To elucidate the function of SPCA2, we studied human colon cancer HCT116 cells, grown under ambient and decreased O2 levels. We found that in contrast with other Ca(2+)-ATPase isoforms the expression of SPCA2 was up-regulated under hypoxia (3% O2), in both adherent (2D) and spheroid (3D) cultures. In spheroids, experiencing lowest O2 levels (30-50 μM, measured by phosphorescence lifetime imaging microscopy), we observed lower staining with reactive oxygen species (ROS)-specific fluorescent probe, which correlated with increased SPCA2. However, SPCA2 expression was up-regulated in cells exposed to reactive oxygen and nitrogen species donors, and when grown at higher density. We noticed that the culture exposed to hypoxia showed overall increase in S phase-positive cells and hypothesized that SPCA2 up-regulation under hypoxia can be linked to Mn(2+)-dependent cell cycle arrest. Consequently, we found that SPCA2-transfected cells display a higher number of cells entering S phase. Altogether, our results point at the important role of SPCA2 in regulation of cell cycle in cancer cells.
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21
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Bijli KM, Kang BY, Sutliff RL, Hart CM. Proline-rich tyrosine kinase 2 downregulates peroxisome proliferator-activated receptor gamma to promote hypoxia-induced pulmonary artery smooth muscle cell proliferation. Pulm Circ 2016; 6:202-10. [PMID: 27252847 DOI: 10.1086/686012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Hypoxia stimulates pulmonary hypertension (PH), in part by increasing the proliferation of human pulmonary artery smooth muscle cells (HPASMCs) via sustained activation of mitogen-activated protein kinase, extracellular signal-regulated kinases 1 and 2 (ERK 1/2), and nuclear factor-kappa B (NF-κB); elevated expression of NADPH oxidase 4 (Nox4); and downregulation of peroxisome proliferator-activated receptor gamma (PPARγ) levels. However, the upstream mediators that control these responses remain largely unknown. We hypothesized that proline-rich tyrosine kinase 2 (Pyk2) plays a critical role in the mechanism of hypoxia-induced HPASMC proliferation. To test this hypothesis, HPASMCs were exposed to normoxia or hypoxia (1% O2) for 72 hours. Hypoxia activated Pyk2 (detected as Tyr402 phosphorylation), and inhibition of Pyk2 with small interfering RNA (siRNA) or tyrphostin A9 attenuated hypoxia-induced HPASMC proliferation. Pyk2 inhibition attenuated ERK 1/2 activation as early as 24 hours after the onset of hypoxia, suggesting a proximal role for Pyk2 in this response. Pyk2 inhibition also attenuated hypoxia-induced NF-κB activation, reduced HPASMC PPARγ messenger RNA levels and activity, and increased NF-κB-mediated Nox4 levels. The siRNA-mediated PPARγ knockdown enhanced Pyk2 activation, whereas PPARγ overexpression reduced Pyk2 activation in HPASMCs, confirming a reciprocal relationship between Pyk2 and PPARγ. Pyk2 depletion also attenuated hypoxia-induced NF-κB p65 activation and reduced PPARγ protein levels in human pulmonary artery endothelial cells. These in vitro findings suggest that Pyk2 plays a central role in the proliferative phenotype of pulmonary vascular wall cells under hypoxic conditions. Coupled with recent reports that hypoxia-induced PH is attenuated in Pyk2 knockout mice, these findings suggest that Pyk2 may represent a novel therapeutic target in PH.
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Affiliation(s)
- Kaiser M Bijli
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia, USA
| | - Bum-Yong Kang
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia, USA
| | - Roy L Sutliff
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia, USA
| | - C Michael Hart
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Atlanta Veterans Affairs and Emory University Medical Centers, Atlanta, Georgia, USA
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22
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Malone PC, Agutter PS. Deep venous thrombosis: The valve cusp hypoxia thesis and its incompatibility with modern orthodoxy. Med Hypotheses 2016; 86:60-6. [DOI: 10.1016/j.mehy.2015.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 10/29/2015] [Accepted: 12/03/2015] [Indexed: 11/25/2022]
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23
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Laganà AS, Sofo V, Salmeri FM, Palmara VI, Triolo O, Terzić MM, Patrelli TS, Lukanovic A, Bokal EV, Santoro G. Oxidative Stress during Ovarian Torsion in Pediatric and Adolescent Patients: Changing The Perspective of The Disease. INTERNATIONAL JOURNAL OF FERTILITY & STERILITY 2015; 9:416-23. [PMID: 26985329 PMCID: PMC4793162 DOI: 10.22074/ijfs.2015.4598] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 09/01/2015] [Indexed: 12/20/2022]
Abstract
Among the different causes of gynecological acute pelvic pain, ovarian torsion represents a surgical emergency. It is a rare case in the pediatric/adolescent aged group
that must be included in the differential diagnosis of any girl with abdominal pain or
pelvic/abdominal mass. Current recommendations suggest that laparoscopic detorsion should be performed in order to preserve the integrity of the ovaries and fertility,
although oophoropexy may be considered in case of severe necrosis. Nevertheless,
maintaining the circulation of the ovary after detorsion deteriorates the tissue injury
and leads to a pathologic process called ischaemia/reperfusion (I/R) injury, which is
characterized by oxidative stress. During the detorsion process, an excess amount of
molecular oxygen is supplied to the tissues, and reactive species of oxygen (ROS)
such as superoxide radical (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH•),
as well as reactive nitrogen species (RNS) are produced in excess. ROS, RNS and
their toxic products cause DNA damage and lipid peroxidation in the cellular and
mitochondrial membranes, leading to cell death. In spite of attention on this topic,
currently there is no shared and clear evidence about the use of anti-inflammatory
and antioxidant agents to prevent I/R damage after laparoscopic ovarian detorsion.
Considering this element, future research should aim to develop shared protocols for
the clinical use (route of application, dosage and time of application) of antioxidants
after laparoscopic management of this condition.
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Affiliation(s)
- Antonio Simone Laganà
- Unit of Gynecology and Obstetrics, Department of Human Pathology in Adulthood and Childhood, G. Barresi, University of Messina, Messina, Italy
| | - Vincenza Sofo
- Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging, University of Messina, Messina, Italy
| | - Francesca Maria Salmeri
- Department of Biomedical Sciences, Dentistry and Morphological and Functional Imaging, University of Messina, Messina, Italy
| | - Vittorio Italo Palmara
- Unit of Gynecology and Obstetrics, Department of Human Pathology in Adulthood and Childhood, G. Barresi, University of Messina, Messina, Italy
| | - Onofrio Triolo
- Unit of Gynecology and Obstetrics, Department of Human Pathology in Adulthood and Childhood, G. Barresi, University of Messina, Messina, Italy
| | - Milan Milosav Terzić
- University of Belgrade, School of Medicine, Belgrade, Serbia; Clinic for Gynecology and Obstetrics, Clinical Center of Serbia, Belgrade, Serbia
| | | | - Adolf Lukanovic
- Department of Gynecology and Obstetrics, University Clinical Center, Ljubljana, Slovenia
| | - Eda Vrtcnik Bokal
- Department of Gynecology and Obstetrics, University Clinical Center, Ljubljana, Slovenia
| | - Giuseppe Santoro
- Department of Biomedical Sciences and Morpho-Functional Images, University of Messina, Messina, Italy
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Fukai K, Nakamura A, Hoshino A, Nakanishi N, Okawa Y, Ariyoshi M, Kaimoto S, Uchihashi M, Ono K, Tateishi S, Ikeda K, Ogata T, Ueyama T, Matoba S. Pyk2 aggravates hypoxia-induced pulmonary hypertension by activating HIF-1α. Am J Physiol Heart Circ Physiol 2015; 308:H951-9. [PMID: 25659487 DOI: 10.1152/ajpheart.00770.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/01/2015] [Indexed: 01/27/2023]
Abstract
Pulmonary arterial hypertension (PAH) is a refractory disease characterized by uncontrolled vascular remodeling and elevated pulmonary arterial pressure. Although synthetic inhibitors of some tyrosine kinases have been used to treat PAH, their therapeutic efficacies and safeties remain controversial. Thus, the establishment of novel therapeutic targets based on the molecular pathogenesis underlying PAH is a clinically urgent issue. In the present study, we demonstrated that proline-rich tyrosine kinase 2 (Pyk2), a nonreceptor type protein tyrosine kinase, plays a crucial role in the pathogenesis of pulmonary hypertension (PH) using an animal model of hypoxia-induced PH. Resistance to hypoxia-induced PH was markedly higher in Pyk2-deficient mice than in wild-type mice. Pathological investigations revealed that medial thickening of the pulmonary arterioles, which is a characteristic of hypoxia-induced PH, was absent in Pyk2-deficient mice, suggesting that Pyk2 is involved in the hypoxia-induced aberrant proliferation of vascular smooth muscle cells in hypoxia-induced PH. In vitro experiments using human pulmonary smooth muscle cells showed that hypoxic stress increased the proliferation and migration of cells in a Pyk2-dependent manner. We also demonstrated that Pyk2 plays a crucial role in ROS generation during hypoxic stress and that this Pyk2-dependent generation of ROS is necessary for the activation of hypoxia-inducible factor-1α, a key molecule in the pathogenesis of hypoxia-induced PH. In summary, the results of the present study reveal that Pyk2 plays an important role in the pathogenesis of hypoxia-induced PH. Therefore, Pyk2 may represent a promising therapeutic target for PAH in a clinical setting.
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Affiliation(s)
- Kuniyoshi Fukai
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Akihiro Nakamura
- Department of Pediatric Cardiology and Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; and
| | - Atsushi Hoshino
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Naohiko Nakanishi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshifumi Okawa
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Makoto Ariyoshi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoshi Kaimoto
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Motoki Uchihashi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazunori Ono
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shuhei Tateishi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Koji Ikeda
- Clinical Pharmacy, Kobe Pharmaceutical University, Hyogo, Japan
| | - Takehiro Ogata
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomomi Ueyama
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan;
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25
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The use of a prostacyclin analog, iloprost, as an adjunct to uterus preservation with histidine-tryptophan-ketoglutarate solution. Transplant Proc 2011; 43:1998-2003. [PMID: 21693315 DOI: 10.1016/j.transproceed.2011.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 03/21/2011] [Accepted: 04/07/2011] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Although assisted reproductive techniques have made most causes of both male and female infertility treatable, uterine factor infertility is not able to therapy. Therefore, transplantation of the uterus has been suggested as a future possible cure. Organ preservation solutions seek to reduce reperfusion injury. Since iloprost is an antioxidant with cytoprotective properties, we investigated its potential positive effects in histidine-tryptophan-ketoglutarate (HTK) solution after 4 or 24 h cold storage period of the rat uterus. METHODS We divided 24 female Wistar-albino rats into four groups: Group 1 had the uterus tissue stored in HTK solution at 4 °C for 4h. Group 2, the tissue was stored in HTK solution combined with iloprost (10(-8) M) for 4h at 4 °C. The same procedures were repeated for 24 h for Groups 3 and 4 respectively. Tissue levels of malondialdehyde (MDA) and nitric oxide (NO), as indicators of oxidative stress were determined with histopathological evaluations. RESULTS MDA and NO levels were compared between the group 1 vs 3; and 2 vs 4. No significant difference was observed between the groups. Cold storage for 24 h produced alterations in histological appearances that were mitigated by the addition of iloprost to HTK solution. CONCLUSION In conclusion, addition of iloprost to HTK solution reversed the histological alterations after 24h-cold storage of the rat uterus.
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26
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Jiang F, Zhang Y, Dusting GJ. NADPH oxidase-mediated redox signaling: roles in cellular stress response, stress tolerance, and tissue repair. Pharmacol Rev 2011; 63:218-42. [PMID: 21228261 DOI: 10.1124/pr.110.002980] [Citation(s) in RCA: 430] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
NADPH oxidase (Nox) has a dedicated function of generating reactive oxygen species (ROS). Accumulating evidence suggests that Nox has an important role in signal transduction in cellular stress responses. We have reviewed the current evidence showing that the Nox system can be activated by a collection of chemical, physical, and biological cellular stresses. In many circumstances, Nox activation fits to the cellular stress response paradigm, in that (1) the response can be initiated by various forms of cellular stresses; (2) Nox-derived ROS may activate mitogen-activated protein kinases (extracellular signal-regulated kinase, p38) and c-Jun NH(2)-terminal kinase, which are the core of the cell stress-response signaling network; and (3) Nox is involved in the development of stress cross-tolerance. Activation of the cell survival pathway by Nox may promote cell adaptation to stresses, whereas Nox may also convey signals toward apoptosis in irreversibly injured cells. At later stage after injury, Nox is involved in tissue repair by modulating cell proliferation, angiogenesis, and fibrosis. We suggest that Nox may have an integral role in cell stress responses and the subsequent tissue repair process. Understanding Nox-mediated redox signaling mechanisms may be of prominent significance at the crossroads of directing cellular responses to stress, aiming at either enhancing the stress resistance (in such situations as preventing ischemia-reperfusion injuries and accelerating wound healing) or sensitizing the stress-induced cytotoxicity for proliferative diseases such as cancer. Therefore, an optimal outcome of interventions on Nox will only be achieved when this is dealt with in a timely and disease-and stage-specific manner.
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Affiliation(s)
- Fan Jiang
- Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Qilu Hospital, Shandong University, 107 Wen Hua Xi Road, Jinan, Shandong 250012, China.
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The effects of iloprost, a prostacyclin analogue, in experimental ischaemia/reperfusion injury in rat ovaries. ACTA ACUST UNITED AC 2009; 61:519-27. [DOI: 10.1016/j.etp.2009.06.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 05/08/2009] [Accepted: 06/22/2009] [Indexed: 11/18/2022]
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Paffett ML, Naik JS, Resta TC, Walker BR. Reduced store-operated Ca2+ entry in pulmonary endothelial cells from chronically hypoxic rats. Am J Physiol Lung Cell Mol Physiol 2007; 293:L1135-42. [PMID: 17693482 DOI: 10.1152/ajplung.00432.2006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic hypoxia (CH)-induced pulmonary hypertension may influence basal endothelial cell (EC) intracellular Ca(2+) concentration ([Ca(2+)](i)). We hypothesized that CH decreases EC [Ca(2+)](i) associated with membrane depolarization and reduced Ca(2+) entry. To test this hypothesis, we assessed 1) basal endothelial Ca(2+) in pressurized pulmonary arteries and freshly isolated ECs, 2) EC membrane potential (E(m)), 3) store-operated Ca(2+) current (I(SOC)), and 4) store-operated Ca(2+) (SOC) entry in arteries from control and CH rats. We found that basal EC Ca(2+) was significantly lower in pressurized pulmonary arteries and freshly isolated ECs from CH rats compared with controls. Similarly, ECs in intact arteries from CH rats were depolarized compared with controls, although no differences were observed between groups in isolated cells. I(SOC) activation by 1 muM thapsigargin displayed diminished inward current and a reversal potential closer to 0 mV in cells from CH rats compared with controls. In addition, SOC entry determined by fura 2 fluorescence and Mn(2+) quenching revealed a parallel reduction in Ca(2+) entry following CH. We conclude that differences in the magnitude of SOC entry exist between freshly dispersed ECs from CH and control rats and correlates with the decrease in basal EC [Ca(2+)](i). In contrast, basal EC Ca(2+) influx is unaffected and membrane depolarization is limited to intact arteries, suggesting that E(m) may not play a major role in determining basal EC [Ca(2+)](i) following CH.
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Affiliation(s)
- Michael L Paffett
- Vascular Physiology Group, Dept. of Cell Biology and Physiology, Univ. of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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Gloria MA, Cenedeze MA, Pacheco-Silva A, Câmara NOS. The blockade of cyclooxygenases-1 and -2 reduces the effects of hypoxia on endothelial cells. Braz J Med Biol Res 2007; 39:1189-96. [PMID: 16981046 DOI: 10.1590/s0100-879x2006000900006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 05/31/2006] [Indexed: 11/21/2022] Open
Abstract
Hypoxia activates endothelial cells by the action of reactive oxygen species generated in part by cyclooxygenases (COX) production enhancing leukocyte transmigration. We investigated the effect of specific COX inhibition on the function of endothelial cells exposed to hypoxia. Mouse immortalized endothelial cells were subjected to 30 min of oxygen deprivation by gas exchange. Acridine orange/ethidium bromide dyes and lactate dehydrogenase activity were used to monitor cell viability. The mRNA of COX-1 and -2 was amplified and semi-quantified before and after hypoxia in cells treated or not with indomethacin, a non-selective COX inhibitor. Expression of RANTES (regulated upon activation, normal T cell expressed and secreted) protein and the protective role of heme oxygenase-1 (HO-1) were also investigated by PCR. Gas exchange decreased partial oxygen pressure (PaO2) by 45.12 +/- 5.85% (from 162 +/- 10 to 73 +/- 7.4 mmHg). Thirty minutes of hypoxia decreased cell viability and enhanced lactate dehydrogenase levels compared to control (73.1 +/- 2.7 vs 91.2 +/- 0.9%, P < 0.02; 35.96 +/- 11.64 vs 22.19 +/- 9.65%, P = 0.002, respectively). COX-2 and HO-1 mRNA were up-regulated after hypoxia. Indomethacin (300 microM) decreased COX-2, HO-1, hypoxia-inducible factor-1alpha and RANTES mRNA and increased cell viability after hypoxia. We conclude that blockade of COX up-regulation can ameliorate endothelial injury, resulting in reduced production of chemokines.
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Affiliation(s)
- M A Gloria
- Laboratório de Imunologia Clínica e Experimental, Divisão de Nefrologia, Universidade Federal de São Paulo, Hospital do Rim e Hipertensão, Fundação Oswaldo Ramos, São Paulo, SP, Brasil
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López-Neblina F, Toledo-Pereyra LH, Toledo AH, Walsh J. Ryanodine receptor antagonism protects the ischemic liver and modulates TNF-alpha and IL-10. J Surg Res 2007; 140:121-8. [PMID: 17359999 DOI: 10.1016/j.jss.2006.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 11/30/2006] [Accepted: 12/02/2006] [Indexed: 11/25/2022]
Abstract
BACKGROUND Dantrolene is a ryanodine receptor and intracellular calcium antagonist. The ryanodine receptor (RyR) Ca(2+) release channel mobilizes Ca(2+) from internal stores to support a variety of cellular functions, including the inflammatory response after ischemia and reperfusion. The pharmacological mechanism of dantrolene is associated with the inhibition of the release of Ca(2+) from the skeletal muscle sarcoplasmic reticulum (SR). We hypothesized that dantrolene could exert a protective effect in our model of liver ischemia and reperfusion by modulating TNF-alpha and IL-10. MATERIAL AND METHODS Mice subjected to 90 min of partial (70 to 80%) hepatic ischemia and 3 h of reperfusion were divided into five groups (n = 6/group): sham, ischemic control, and the dantrolene 1 mg/kg group studied at three times of administration: 15 min before reperfusion (DAN-PRE), at the time of reperfusion (DAN-RP), and 15 min after reperfusion (DAN-POS). The parameters measured at 3 h of reperfusion included serum liver function tests alanine aminotransferase (ALT) and aspartate aminotransferase (AST), TNF-alpha, and IL-10 in serum and liver histology. RESULTS It was demonstrated that the RyR intracellular calcium antagonist dantrolene offered the most significant protection for the ischemic liver when given before reperfusion and at the time of reperfusion. AST significantly differed between the control group and the DAN-PRE and DAN-RP groups (P < 0.05). ALT showed a statistically significant decrease in the DAN-PRE treated group and a decrease, although not significant, in the DAN-RP. Histological examination demonstrated a significant decrease in vacuolization in the same both groups (P < 0.05). Necrosis was significantly diminished when dantrolene was used at the time of reperfusion; congestion decreased in the same groups but without statistical significant difference. The levels of TNF-alpha were significantly decreased in the DAN-RP group. There was a decrease in TNF-alpha in the DAN-PRE group but not statistically significant. IL-10 reflected the protection observed in necrosis and vacuolization in the histopathology with an increment at the time of reperfusion (P < 0.05). DAN-POS did not exert a protective effect in ALT, AST, liver histology, or cytokine response. CONCLUSION For the first time the ryanodine receptor antagonist dantrolene offered significant functional and structural protection of the ischemic liver when given at the time for reperfusion and partial protection when given prereperfusion. RyR inhibition approach down-regulated the expression of TNF-alpha and induced an increment of the protective cytokine IL-10 when administered at the time of reperfusion. There was no protective effect of dantrolene after reperfusion.
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Affiliation(s)
- Fernando López-Neblina
- Trauma, Surgery Research, and Molecular Biology, Borgess Research Institute, Kalamazoo, Michigan 49048, USA
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Matsui Y, Kita S, Katsuragi T, Komuro I, Iwamoto T, Ohjimi H. Involvement of Na+/Ca2+ Exchanger Type-1 in Ischemia-Induced Neovascularization in the Mouse Hindlimb. Ann N Y Acad Sci 2007; 1099:478-80. [PMID: 17303837 DOI: 10.1196/annals.1387.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The Na+/Ca2+ exchanger (NCX) is considered to be involved in endothelial nitric oxide (NO) production and endothelium-dependent vasorelaxation, but little is known about the physiological and pathological roles of endothelial NCX in these processes. We examined the role of NCX1 in neovascularization in mice with hindlimb ischemia. Unilateral hindlimb ischemia was induced surgically in wild-type and heterozygous NCX1 knockout mice (NCX1+/-) mice. We found that in NCX1+/- mice, blood flow recovery was significantly augmented compared with that in wild-type mice. N(G)-nitro-L-arginine methyl ester treatment eliminated enhanced angiogenesis observed in NCX1+/- mice. These results suggest that NCX1 is involved in eNOS-dependent angiogenesis.
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Affiliation(s)
- Yukiko Matsui
- Department of Plastic and Reconstructive Surgery, Fukuoka University, Fukuoka 814-0180, Japan
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Kobayashi S, Crooks S, Eckmann DM. Dose- and time-dependent liquid sclerosant effects on endothelial cell death. Dermatol Surg 2007; 32:1444-52. [PMID: 17199651 DOI: 10.1111/j.1524-4725.2006.32350.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Intravenous sclerotherapy solutions can induce endothelial cell death. OBJECTIVE The objective was to determine the relationship between sclerosant concentration and minimum contact time required for in endothelial cell death. METHODS Cultured bovine aortic endothelial cells were exposed to a broad range of concentrations of two liquid sclerosants, polidocanol and sodium tetradecyl sulfate. Fluorescence microscopy was used to study cells using dyes specifically indicating changes in intracellular calcium levels, nitric oxide production, and loss of cell membrane integrity after sclerosant exposure. Fluorescence intensity measurements were used to identify the timing of cell death. RESULTS Calcium signaling and nitric oxide pathways were activated by the administration of the sclerosants and were followed by cell death. The time to the activation and the cell death was dependent on the concentration of sclerosants. At 0.3% polidocanol or 0.1% sodium tetradecyl sulfate, cell death occurred within 15 minutes. At less than 0.003% polidocanol and at 0.005% sodium tetradecyl sulfate, cells remained alive after 60 minutes. CONCLUSION Both sclerosants rapidly led to cell death at sufficiently high concentrations. At low sclerosant concentrations, cell viability was maintained beyond the recording time of the experiment. The timing of endothelial cell death is predictable based on sclerosant concentration during exposure.
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Affiliation(s)
- Shunji Kobayashi
- Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
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33
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Dose- and Time-Dependent Liquid Sclerosant Effects on Endothelial Cell Death. Dermatol Surg 2006. [DOI: 10.1097/00042728-200612000-00003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Transcription from the human cytosolic phospholipase A2 gene has been observed to be hypoxia sensitive in endothelial cells cultured from the human cerebral microvasculature. DNA sequence analysis of the cytosolic phospholipase A2 promoter revealed the presence of a distal cluster of potential hypoxia-inducible factor-1-DNA binding sites homologous to 5'-NCGTG-3', located between -1087 and -996 bp of the major start of transcription at +1 bp (Genbank U08374). Gel shift assay showed strong hypoxia-inducible factor-1-DNA binding to only a single site within this cluster, and promoter deletion analysis indicated the functional importance of this chromatin domain in conveying oxygen sensitivity to cytosolic phospholipase A2 gene transcription. Non-functional hypoxia inducible factor-1-DNA binding sites flanking a single functional hypoxia-inducible factor-1-DNA binding site in this hypoxia-sensitive domain may promote oxygen sensitivity via transcription factor clustering or Circe effects.
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Véga C, R Sachleben L, Gozal D, Gozal E. Differential metabolic adaptation to acute and long-term hypoxia in rat primary cortical astrocytes. J Neurochem 2006; 97:872-83. [PMID: 16573648 DOI: 10.1111/j.1471-4159.2006.03790.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Brain astrocytes provide structural and metabolic support to surrounding cells during ischemia. Glucose and oxygen are critical to brain function, and glucose uptake and metabolism by astrocytes are essential to their metabolic coupling to neurons. To examine astrocyte metabolic response to hypoxia, cell survival and metabolic parameters were assessed in rat primary cortical astrocytes cultured for 3 weeks in either normoxia or in either 1 day or 3 weeks sustained hypoxia (5% O2). Although cell survival and proliferation were not affected by the mildly hypoxic environment, substantial differences in glucose consumption and lactate release after either acute or prolonged hypoxia suggest that astrocyte metabolism may contribute to their adaptation. Hypoxia over a period of 1 day increased glucose uptake, lactate release, and glucose transporter 1 (GLUT1) and monocarboxylate transporter 1 (MCT1) expression, whereas hypoxia over a period of 3 weeks resulted in a decrease of all parameters. Furthermore, increased glucose uptake at 1 day of hypoxia was not inhibited by cytochalasin B suggesting the involvement of additional glucose transporters. We uncovered hypoxia-regulated expression of sodium-dependent glucose transporters (SGLT1) in astrocytes indicating a novel adaptive strategy involving both SGLT1 and GLUT1 to regulate glucose intake in response to hypoxia. Overall, these findings suggest that although increased metabolic response is required for the onset of astrocyte adaptation to hypoxia, prolonged hypoxia requires a shift to an energy conservation mode. These findings may contribute to the understanding of the relative tolerance of astrocytes to hypoxia compared with neurons and provide novel therapeutic strategies aimed at maintaining brain function in cerebral pathologies involving hypoxia.
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Affiliation(s)
- Céline Véga
- Department of Pediatrics, Kosair Children's Hospital Research Institute, University of Louisville, Louisville, Kentucky 40202, USA
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36
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Feitoza CQ, Câmara NOS, Pinheiro HS, Gonçalves GM, Cenedeze MA, Pacheco-Silva A, Santos OFP. Cyclooxygenase 1 and/or 2 blockade ameliorates the renal tissue damage triggered by ischemia and reperfusion injury. Int Immunopharmacol 2005; 5:79-84. [PMID: 15589463 DOI: 10.1016/j.intimp.2004.09.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ischemia-reperfusion injury (IRI) is a common event in organ transplantation, being implicated as a potential contributor for the development of chronic allograft nephropathy. There are new evidences showing a tissue inflammatory response following renal IRI. Cyclooxygenases (COX) 1 and 2 can be detected in tissue submitted to IRI and may have impact on organ function outcome. We evaluated the role of COX inhibition on the renal tissue damage that follows IRI. Mice were submitted to 45 min of renal pedicle ligature and allowed to reperfuse for 24, 48, 72 and 120 h. Blood and kidney samples were collected at reperfusion times. mRNA was extracted from the kidney samples to amplify COX-1, COX-2 and beta-actin genes. Animals were pretreated with indomethacin or rofecoxib before the surgery. Indomethacin treatment induced a better renal function (serum urea) when compared to control animals at 24, 48 and 72 h (219+/-54.5 vs. 338+/-51 mg/dl; 106+/-51 vs. 326+/-86 mg/dl; 94+/-14 vs. 138+/-38 mg/dl, respectively). Surprisingly, rofecoxib use was associated with even better renal improvement following IR. Animals treated with the later drug showed lower urea values at 24 h post reperfusion compared to indomethacin-treated animals (128+/-33 vs. 219+/-54.5 mg/dl, P<0.05). Blockade of COX-1 and -2 resulted in a decrease of tubular necrosis. mRNA COX-2 was up-regulated post IRI and considerable inhibited after indomethacin or rofecoxib treatment. Our data show COX-1/-2 participates in the inflammatory tissue response to IR injury and its inhibition is associated with an improvement in renal function.
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Affiliation(s)
- Carla Q Feitoza
- Laboratory of Clinical and Experimental Immunology, Departamento de Medicina, Disciplina de Nefrologia, Hospital do Rim e Hipertensão, Universidade Federal de São Paulo, Rua Botucatu 740, Vila Clementino, 04023-900, São Paulo, Brazil
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Rose K, Ouellette Y, Bolon M, Tyml K. Hypoxia/reoxygenation reduces microvascular endothelial cell coupling by a tyrosine and MAP kinase dependent pathway. J Cell Physiol 2005; 204:131-8. [PMID: 15672421 DOI: 10.1002/jcp.20283] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Communication of electrical signals along the microvascular endothelium plays a key role in integrating microvascular function required for local regulation of blood flow. The aim of the present study was to examine the effect of a short-term hypoxia (0.1% O(2), 1 h) plus reoxygenation (H/R) on electrical coupling in cultured monolayers of microvascular endothelial cells (rat skeletal muscle origin). To assess coupling, we used a current injection technique and a Bessel function model to compute the intercellular resistance (an inverse measure of coupling) and cell membrane resistivity (a measure of resistance to current leakage across the cell membrane). H/R resulted in rapid (within 4 min after reoxygenation) and sustained (up to 100 min) reduction in intercellular coupling, but it did not alter membrane resistivity. H/R did not alter gap junction protein connexin 43 expression nor its tyrosine phosphorylation as determined by immunoblot and immunoprecipitation analyses. Inhibition of mitochondrial respiration (1 mM NaCN) did not mimic the effect of H/R. However, pre-treatment of monolayers with tyrphostin A48 (1.5 microM), PP2 (10 nM) (tyrosine kinase inhibitors), U 0126 (20 microM), and PD 98059 (5 microM) (MEK1/2 inhibitors) inhibited the H/R-induced reduction in coupling. These results indicate that endothelial cell coupling was reduced quickly after reoxygenation, via activation of a tyrosine and MAP kinase dependent pathway. We predict that a short-term H/R can rapidly compromise microvascular function in terms of reduced cellular communication along the vascular wall.
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Affiliation(s)
- Keeley Rose
- Lawson Health Research Institute, London, Ontario, Canada
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Zani BG, Bohlen HG. Transport of extracellular l-arginine via cationic amino acid transporter is required during in vivo endothelial nitric oxide production. Am J Physiol Heart Circ Physiol 2005; 289:H1381-90. [PMID: 15849232 DOI: 10.1152/ajpheart.01231.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In cultured endothelial cells, 70-95% of extracellular l-arginine uptake has been attributed to the cationic amino acid transporter-1 protein (CAT-1). We tested the hypothesis that extracellular l-arginine entry into endothelial cells via CAT-1 plays a crucial role in endothelial nitric oxide (NO) production during in vivo conditions. Using l-lysine, the preferred amino acid transported by CAT-1, we competitively inhibited extracellular l-arginine transport into endothelial cells during conditions of NaCl hyperosmolarity, low oxygen, and flow increase. Our prior studies indicate that each of these perturbations causes NO-dependent vasodilation. The perivascular NO concentration ([NO]) and blood flow were determined in the in vivo rat intestinal microvasculature. Suppression of extracellular l-arginine transport significantly and strongly inhibited increases in vascular [NO] and intestinal blood flow during NaCl hyperosmolarity, lowered oxygen tension, and increased flow. These results suggest that l-arginine from the extracellular space is accumulated by CAT-1. When CAT-1-mediated transport of extracellular l-arginine into endothelial cells was suppressed, the endothelial cell NO response to a wide range of physiological stimuli was strongly depressed.
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Affiliation(s)
- Brett G Zani
- Department of Cellular and Integrative Physiology, Indiana University Medical School, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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Fan Y, Wu DZ, Gong YQ, Zhou JY, Hu ZB. Effects of calycosin on the impairment of barrier function induced by hypoxia in human umbilical vein endothelial cells. Eur J Pharmacol 2004; 481:33-40. [PMID: 14637172 DOI: 10.1016/j.ejphar.2003.09.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The purpose of the present study was to examine the effects of calycosin, an isoflavonoid isolated from Astragali Radix, on the impairment of barrier function induced by hypoxia in cultured human umbilical vein endothelial cells. Hypoxia induced an increase in endothelial cell monolayer permeability, indicating endothelial cell barrier impairment. Endothelial barrier dysfunction induced by hypoxia was accompanied by decreases in cytosolic ATP concentration and cAMP level, the development of actin stress fibers and intercellular gap formation, suggesting that the decreases in cytosolic ATP and cAMP levels and rearrangements of F-actin could be associated with an increase in permeability of endothelial monolayers. Application of calycosin inhibited the hypoxia-induced increase in endothelial permeability in a dose-dependent fashion, which is compatible with inhibition of lactate dehydrogenase release, decrease of the fall in ATP and cAMP contents, and improvement of F-actin rearrangements. These findings indicate that calycosin protected endothelial cells from hypoxia-induced barrier impairment by increasing intracellular energetic sources and promoting regeneration of the cAMP level, as well as improving cytoskeleton remodeling.
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Affiliation(s)
- Yi Fan
- Institute of Chinese Materia Medica, WHO Collaborating Center for Traditional Medicine, Shanghai University of Traditional Chinese Medicine, 530 LingLing Road, Shanghai 200032, People's Republic of China
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Elfeber K, Köhler A, Lutzenburg M, Osswald C, Galla HJ, Witte OW, Koepsell H. Localization of the Na+-D-glucose cotransporter SGLT1 in the blood-brain barrier. Histochem Cell Biol 2004; 121:201-7. [PMID: 14986005 DOI: 10.1007/s00418-004-0633-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2004] [Indexed: 10/26/2022]
Abstract
Immunoreactivity of the Na+-D-glucose cotransporter SGLT1 was demonstrated in intracerebral capillaries of rat and pig. Immunostaining suggested that SGLT1 is located in the luminal membrane of the endothelial cells and in intracellular vesicles. Using in situ hybridization, SGLT1 mRNA was not detectable in intracerebral capillaries of non-treated or sham-operated Wistar rats. However, 1 day after a transient occlusion of the right middle cerebral artery, SGLT1 mRNA was detected in capillaries of both brain hemispheres. Expression of SGLT1 was also demonstrated in primary cultures of capillary endothelial cells from pig using polymerase chain reaction after reverse transcription and western blotting. The data suggest that SGLT1 participates in transport of D-glucose across the blood-brain barrier and is upregulated after brain ischemia and reperfusion.
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Affiliation(s)
- Katrin Elfeber
- Institute of Anatomy and Cell Biology, University Würzburg, Koellikerstrasse 6, 97070 Würzburg, Germany
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Ogura J, Mitamura M, Someya A, Shimamura K, Takayama H, Aimi N, Horie S, Murayama T. Mesaconitine-induced relaxation in rat aorta: role of Na+/Ca2+ exchangers in endothelial cells. Eur J Pharmacol 2004; 483:139-46. [PMID: 14729101 DOI: 10.1016/j.ejphar.2003.10.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Previously, we reported that mesaconitine, an aconite alkaloid, increased intracellular Ca(2+) concentration ([Ca(2+)](i)) level in endothelium and caused relaxation in rat aorta via nitric oxide production. In the present study, we investigated the mechanisms of increase in the [Ca(2+)](i) level induced by mesaconitine in rat aorta and in human umbilical vein endothelial cells (HUVECs). Treatment with the low Na(+) buffer delayed the 30 microM mesaconitine-, but not 10 microM acetylcholine-, induced relaxation in rat aorta. Treatments with an inhibitor of Na(+)/Ca(2+) exchangers (20 microM 3',4'-dichlorobenzamil) and a reversed mode (Ca(2+) influx) inhibitor of the exchangers (30 microM 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate, KBR7943) showed similar effects. In HUVECs, 30 microM mesaconitine increased the [Ca(2+)](i) level in the presence of extracellular CaCl(2) and NaCl, and the response was inhibited by KBR7943. Mesaconitine increased intracellular Na(+) concentration level in HUVECs. The [Ca(2+)](i) response by mesaconitine was inhibited by 100 microM D-tubocurarine (an inhibitor of nicotinic acetylcholine receptors), but was not inhibited in the glucose-free buffer and by inhibitors of Na(+)/H(+) exchangers. These findings suggest that mesaconitine stimulated Ca(2+) influx via the Na(+)/Ca(2+) exchangers in endothelial cells and caused relaxation in the aorta. The possibility of D-tubocurarine-sensitive Na(+) channels as target(s) of mesaconitine is discussed.
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Affiliation(s)
- Junko Ogura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 263-8522, Japan
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Fradette C, Souich PD. Hypoxia-inducible factor-1 and activator protein-1 modulate the upregulation of CYP3A6 induced by hypoxia. Br J Pharmacol 2003; 140:1146-54. [PMID: 14559859 PMCID: PMC1574128 DOI: 10.1038/sj.bjp.0705543] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
1. Moderate hypoxia in vivo and serum from rabbits subjected to moderate hypoxia (SHYPO) in vitro reduce CYP1A1 and 1A2 p450 isoforms and upregulate CYP3A6. The aim of this project was to investigate the signal transduction pathways implicated in the upregulation of CYP3A6 expression by hypoxia. 2. Hypoxia in vivo and SHYPO in vitro increased the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) and c-jun, as well as CYP3A6. By electrophoresis mobility shift assay, it was shown that HIF-1 and activator protein-1 (AP-1) bind to CYP3A6 oligonucleotide probe after exposure to hypoxia in vivo and SHYPO in vitro. The effects of hypoxia in vivo or SHYPO in vitro were reproduced by CoCl2 and lead acetate, activators of HIF-1 and AP-1, respectively. 2. PD98059, a p42/44 MAPK inhibitor, prevented the increase of CYP3A6 and c-jun, but did not impede the increase of HIF-1alpha and binding to CYP3A6 oligonucleotide probe. Genistein, an inhibitor of protein tyrosine kinases (PTKs), prevented the increase in HIF-1alpha, c-jun and CYP3A6, as well as HIF-1 and AP-1 binding to CYP3A6 oligonucleotide probe. Moreover, hypoxia in vivo induced constitutive androstane receptor (CAR) as well as CAR binding to the CYP3A6 oligonucleotide probe, but not the pregnane X receptor. 4. In conclusion, hypoxia in vivo and SHYPO induce the expression of CYP3A6. The in vitro induction of CYP3A6 by SHYPO is PTK- and p42/44 MAPK-dependent. The present data support the hypothesis that HIF-1 and AP-1 are part of the signalling pathway leading to CYP3A6 induction by hypoxia.
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Affiliation(s)
- Caroline Fradette
- Department of Pharmacology, Faculty of Medicine, University of Montréal, PO Box 6128, Stat. Centre-Ville, Montréal, Québec, Canada H3C 3J7
| | - Patrick du Souich
- Department of Pharmacology, Faculty of Medicine, University of Montréal, PO Box 6128, Stat. Centre-Ville, Montréal, Québec, Canada H3C 3J7
- Author for correspondence:
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Maczewski M, Beresewicz A. Role of nitric oxide and free radicals in cardioprotection by blocking Na+/H+ and Na+/Ca2+ exchange in rat heart. Eur J Pharmacol 2003; 461:139-47. [PMID: 12586209 DOI: 10.1016/s0014-2999(03)01302-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Inhibition of Na(+)/H(+) (NHE) and Na(+)/Ca(2+) (NCE) exchangers prevents myocardial ischemia/reperfusion injury by preventing cardiomyocyte Ca(2+) overload. We hypothesized that it may influence ischemic/reperfused myocardium also indirectly by preventing endothelial Ca(2+) accumulation, and thereby by attenuating reperfusion-induced formation of nitric oxide (NO) and/or oxygen free radicals. Langendorff-perfused rat hearts were subjected to 30-min ischemia and 30-min reperfusion. Myocardial outflow of NO (nitrite+nitrate) and hydroxyl radical (*OH, salicylate method), and functional recoveries were followed during reperfusion. In all groups, there was a transient rise in NO and *OH outflow upon reperfusion. An inhibitor of NHE, cariporide (10 microM) [(4-Isopropyl-3-methylsulfonyl-benzoyl)-quanidine methanesulfonate], and an inhibitor of the reverse mode of NCE, KB-R7943 (5 microM) (2-[4-(4-Nitrobenzyloxy)phenyl]ethyl]isothiourea mesylate), decreased NO and *OH formation, reduced contracture, and improved the recovery of mechanical function during reperfusion, compared to the untreated hearts. The formation of NO was reduced by 40% by 100 microM N(G)-methyl-L-arginine acetate salt (L-NMMA, NO synthase inhibitor), and not affected by 50 microM L-NMMA. *OH formation, contracture, and the functional recoveries were affected neither by 50 nor by 100 microM L-NMMA. Also, the effects of cariporide and KB-R7943 were unaffected by 100 microM L-NMMA. This study shows for the first time that the inhibition of NHE and NCE attenuates post-ischemic myocardial formation of NO and *OH, suggesting that prevention of Ca(2+) overload is cardioprotective via these mechanisms. The results indicate, however, that NO synthase pathway did not interfere with the protection afforded by NHE or NCE in our model.
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Affiliation(s)
- Michał Maczewski
- Department of Clinical Physiology, Medical Center of Postgraduate Education, Marymoncka 99, 01-813 Warsaw, Poland
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Abstract
Amphetamine stimulates particulate protein kinase C (PKC) activity that is associated with the outward-transport of dopamine (DA) (Giambalvo [2003] Synapse 49:125-133). This stimulatory effect requires intracellular calcium ([Ca](i)) and endogenous DA and when DA release is diminished, the inward-transport of amphetamine inhibits PKC activity. This study examines the mechanisms involved. It was found that synaptoneurosomes incubated with amphetamine showed a dose-dependent increase in phospholipase C and A(2) activities. Furthermore, pretreatments with the phospholipase C inhibitor D609 or the phospholipase A(2) inhibitors quinacrine or p-bromophenacylbromide attenuated the amphetamine-induced increase in PKC activity. This suggests that both phospholipases were essential for the amphetamine-induced increase in PKC activity. The Na/Ca antiporter was also involved, since pretreatment with amiloride or benzamil attenuated the amphetamine-induced increase in PKC activity. Since these drugs by themselves increased PKC activity, the return to basal activity after addition of amphetamine suggests that, in the absence of Na/Ca exchange, amphetamine had an inhibitory effect on PKC activity. This inhibitory effect might be due to the activation of phospholipase A(2) through an increase in intracellular pH induced by amphetamine. This was supported by the finding that pretreatment with dimethylamiloride, an inhibitor of the Na/H antiporter that increases intracellular [H(+)], attenuated the effects of amphetamine on PKC activity. Other drugs that decrease intracellular [H(+)] (ammonia, monensin) also inhibited PKC activity without Ca. In contrast to amphetamine, monensin had no effect on PKC activity with Ca. This could be related to its large differential effects on phospholipase A(2) vs. phospholipase C activity. Thus, the monensin-mediated decrease in PKC activity seen without Ca was partially attenuated by pretreatment with quinacrine. Furthermore, when Na/Ca antiporter was inhibited with benzamil, monensin inhibited PKC activity. These results suggest that amphetamine, as well as monensin, may have dual effects on PKC activity, a Ca-dependent stimulatory effect via phospholipase C, and an inhibitory effect via phospholipase A(2).
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Affiliation(s)
- Cecilia T Giambalvo
- Rhode Island Psychiatric Research Center, Eleanor Slater Hospital, Cranston, Rhode Island 02920, USA
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